diff --git a/.eslintignore b/.eslintignore
index 3a749f2574..ab54c23dc6 100644
--- a/.eslintignore
+++ b/.eslintignore
@@ -3,25 +3,24 @@
 
 # Always ignore crashtests - specially crafted files that originally caused a
 # crash.
-**/crashtests/**
+**/crashtests/
 # Also ignore reftest - specially crafted to produce expected output.
-**/reftest/**
-**/reftests/**
+**/reftest/
+**/reftests/
 
 # Exclude expected objdirs.
-obj*/**
+obj*/
 
 # dom/ exclusions which should be removed (aka ESLint enabled)
-dom/base/*.*
-dom/media/test/**
+dom/media/test/
 !dom/media/test/marionette/yttest/*.js
-dom/xhr/**
+dom/xhr/
 
 # build/ third-party code
-build/pgo/js-input/**
+build/pgo/js-input/
 
 # browser/ exclusions
-browser/app/**
+browser/app/
 browser/branding/**/firefox-branding.js
 # Gzipped test file.
 browser/base/content/test/general/gZipOfflineChild.html
@@ -34,27 +33,26 @@ browser/components/sessionstore/test/unit/data/sessionstore_invalid.js
 # code as a .jsm (schema.jsm)
 browser/components/enterprisepolicies/schemas/schema.jsm
 # generated & special files in cld2
-browser/components/translation/cld2/**
+browser/components/translation/cld2/
 # Screenshots is imported as a system add-on and has
 # their own lint rules currently.
-browser/extensions/screenshots/**
-browser/extensions/pdfjs/content/build**
-browser/extensions/pdfjs/content/web**
+browser/extensions/screenshots/
+browser/extensions/pdfjs/content/build
+browser/extensions/pdfjs/content/web
 # generated or library files in pocket
 browser/components/pocket/content/panels/js/tmpl.js
-browser/components/pocket/content/panels/js/vendor/**
+browser/components/pocket/content/panels/js/vendor/
 
 # Ignore newtab files
 # Kept in sync with browser/components/newtab/.eslintignore
 browser/components/newtab/data/
 browser/components/newtab/logs/
-browser/components/newtab/prerendered/
 browser/components/newtab/vendor/
 
 # The only file in browser/locales/ is pre-processed.
-browser/locales/**
+browser/locales/
 # imported from chromium
-browser/extensions/mortar/**
+browser/extensions/mortar/
 # Generated data files
 browser/extensions/formautofill/phonenumberutils/PhoneNumberMetaData.jsm
 
@@ -80,63 +78,61 @@ devtools/client/shared/webpack/shims/test/test_clipboard.html
 devtools/shared/qrcode/tests/mochitest/test_decode.html
 devtools/shared/tests/mochitest/*.html
 devtools/shared/webconsole/test/test_*.html
+devtools/server/tests/mochitest/test_inspector-inactive-property-helper.html
 
 # Ignore devtools debugger files
 # Keep in sync with devtools/client/debugger/.eslintignore
 devtools/client/debugger/assets/*
-devtools/client/debugger/src/test/examples/**
-devtools/client/debugger/src/test/integration/**
-devtools/client/debugger/src/test/unit-sources/**
-devtools/client/debugger/src/**/fixtures/**
-devtools/client/debugger/src/test/mochitest/**
+devtools/client/debugger/src/test/examples/
+devtools/client/debugger/src/test/integration/
+devtools/client/debugger/src/test/unit-sources/
+devtools/client/debugger/src/**/fixtures/
+devtools/client/debugger/src/test/mochitest/
 devtools/client/debugger/bin/
-devtools/client/debugger/packages/**/fixtures/**
+devtools/client/debugger/packages/**/fixtures/
 devtools/client/debugger/node_modules
 devtools/client/debugger/out
 
 # Ignore devtools debugger files which aren't intended for linting, and also
 # aren't included in any .eslintignore or .prettierignore file.
 # See https://github.com/firefox-devtools/debugger/blob/master/package.json#L24
-devtools/client/debugger/configs/**
-devtools/client/debugger/dist/**
-devtools/client/debugger/flow-typed/**
-devtools/client/debugger/images/**
-devtools/client/debugger/test/**
+devtools/client/debugger/configs/
+devtools/client/debugger/dist/
+devtools/client/debugger/flow-typed/
+devtools/client/debugger/images/
+devtools/client/debugger/test/
 devtools/client/debugger/index.html
 
 # Ignore devtools imported repositories
-devtools/client/shared/components/reps/**
+devtools/client/shared/components/reps/
 
 # Ignore devtools preferences files
-devtools/client/preferences/**
-devtools/client/webide/preferences/**
-devtools/shared/preferences/**
-devtools/startup/preferences/devtools-startup.js
+devtools/client/preferences/
 
 # Ignore devtools generated code
 devtools/shared/css/generated/properties-db.js
-devtools/client/webconsole/test/fixtures/stubs/*.js
-!devtools/client/webconsole/test/fixtures/stubs/index.js
+devtools/client/webconsole/test/node/fixtures/stubs/*.js
+!devtools/client/webconsole/test/node/fixtures/stubs/index.js
 
 # Ignore devtools third-party libs
-devtools/shared/jsbeautify/*
-devtools/shared/acorn/*
-devtools/shared/node-properties/*
-devtools/shared/pretty-fast/*
-devtools/shared/sourcemap/*
-devtools/shared/sprintfjs/*
-devtools/shared/qrcode/decoder/*
-devtools/shared/qrcode/encoder/*
+devtools/shared/jsbeautify/
+devtools/shared/acorn/
+devtools/shared/node-properties/
+devtools/shared/pretty-fast/
+devtools/shared/sourcemap/
+devtools/shared/sprintfjs/
+devtools/shared/qrcode/decoder/
+devtools/shared/qrcode/encoder/
 devtools/client/inspector/markup/test/lib_*
 devtools/client/jsonview/lib/require.js
 devtools/client/shared/demangle.js
-devtools/client/shared/source-map/*
-devtools/client/shared/vendor/*
+devtools/client/shared/source-map/
+devtools/client/shared/vendor/
 devtools/client/shared/sourceeditor/codemirror/*.js
 devtools/client/shared/sourceeditor/codemirror/**/*.js
-devtools/client/shared/sourceeditor/tern/*
+devtools/client/shared/sourceeditor/tern/
 devtools/client/shared/sourceeditor/test/cm_mode_ruby.js
-devtools/client/shared/sourceeditor/test/codemirror/*
+devtools/client/shared/sourceeditor/test/codemirror/
 devtools/server/actors/utils/automation-timeline.js
 
 # Ignore devtools files testing sourcemaps / code style
@@ -144,20 +140,23 @@ devtools/client/debugger/test/mochitest/code_*.js
 devtools/client/framework/test/code_*
 devtools/client/inspector/markup/test/events_bundle.js
 devtools/client/netmonitor/test/xhr_bundle.js
-devtools/client/webconsole/test/mochitest/code_bundle_nosource.js
-devtools/client/webconsole/test/mochitest/code_bundle_invalidmap.js
+devtools/client/webconsole/test/browser/code_bundle_nosource.js
+devtools/client/webconsole/test/browser/code_bundle_invalidmap.js
 devtools/server/tests/unit/babel_and_browserify_script_with_source_map.js
 devtools/server/tests/unit/setBreakpoint*
 devtools/server/tests/unit/sourcemapped.js
 
+# Testing syntax error
+devtools/client/webconsole/test/browser/test-syntaxerror-worklet.js
+
 # devtools specific format test file
 devtools/server/tests/unit/xpcshell_debugging_script.js
 
 # Third-party
-dom/canvas/test/webgl-conf/**
-dom/imptests/**
-dom/media/webaudio/test/blink/**
-dom/media/webvtt/**
+dom/canvas/test/webgl-conf/
+dom/imptests/
+dom/media/webaudio/test/blink/
+dom/media/webvtt/
 dom/svg/test/test_nonAnimStrings.xhtml
 dom/svg/test/test_SVG_namespace_ids.html
 
@@ -193,39 +192,39 @@ dom/workers/test/invalid.js
 dom/workers/test/threadErrors_worker1.js
 
 # Third-party
-editor/libeditor/tests/browserscope/**
+editor/libeditor/tests/browserscope/
 
 # Third-party
-gfx/ots/**
-gfx/skia/**
-gfx/wr/**
+gfx/ots/
+gfx/skia/
+gfx/wr/
 
 # intl/ exclusions
-intl/icu/**
+intl/icu/
 # Bug 1527075: This directory is linted in github repository
-intl/l10n/**
+intl/l10n/
 
 # Third-party
-layout/mathml/imptests/**
+layout/mathml/imptests/
 
 # Exclude everything but self-hosted JS
-js/ductwork/**
-js/examples/**
-js/ipc/**
-js/public/**
-js/xpconnect/**
-js/src/devtools/**
-js/src/octane/**
-js/src/jit-test/**
-js/src/jsapi-tests/binast/**
-js/src/tests/**
+js/ductwork/
+js/examples/
+js/ipc/
+js/public/
+js/xpconnect/
+js/src/devtools/
+js/src/octane/
+js/src/jit-test/
+js/src/jsapi-tests/binast/
+js/src/tests/
 js/src/Y.js
 
 # Third-party
-media/webrtc/trunk/**
+media/webrtc/trunk/
 
 # mobile/android/ exclusions
-mobile/android/tests/browser/chrome/tp5/**
+mobile/android/tests/browser/chrome/tp5/
 
 # Uses `#filter substitution`
 mobile/android/app/mobile.js
@@ -241,10 +240,10 @@ mobile/android/locales/
 # Pre-processed/pref files
 modules/libpref/greprefs.js
 modules/libpref/init/all.js
-modules/libpref/test/unit/*data/**
+modules/libpref/test/unit/*data/
 
 # Only contains non-standard test files.
-python/**
+python/
 
 # Remote agent
 remote/Protocol.jsm
@@ -256,7 +255,7 @@ remote/test/browser/chrome-remote-interface.js
 remote/test/demo.js
 
 # NSS / taskcluster only.
-security/nss/**
+security/nss/
 
 # services/ exclusions
 
@@ -271,7 +270,7 @@ services/fxaccounts/FxAccountsPairingChannel.js
 services/sync/modules/constants.js
 
 # Servo is imported.
-servo/**
+servo/
 
 # Remote protocol exclusions
 testing/marionette/atom.js
@@ -282,35 +281,37 @@ testing/marionette/harness
 
 # other testing/ exclusions
 # third party modules
-testing/mochitest/tests/Harness_sanity/**
-testing/mochitest/MochiKit/**
-testing/mochitest/tests/MochiKit-1.4.2/**
-testing/mochitest/tests/SimpleTest/**
+testing/mochitest/tests/Harness_sanity/
+testing/mochitest/MochiKit/
+testing/mochitest/tests/MochiKit-1.4.2/
+testing/mochitest/tests/SimpleTest/
 testing/modules/ajv-4.1.1.js
 testing/modules/sinon-7.2.7.js
 # octothorpe used for pref file comment causes parsing error
 testing/mozbase/mozprofile/tests/files/prefs_with_comments.js
+
+# Mozproxy third party
+testing/mozbase/mozproxy/mozproxy/backends/mitm/scripts/catapult/
+
 testing/talos/talos/scripts/jszip.min.js
 testing/talos/talos/startup_test/sessionrestore/profile/sessionstore.js
 testing/talos/talos/startup_test/sessionrestore/profile-manywindows/sessionstore.js
-testing/talos/talos/tests/devtools/addon/content/pages/**
-testing/talos/talos/tests/dromaeo/**
-testing/talos/talos/tests/v8_7/**
-testing/talos/talos/tests/kraken/**
+testing/talos/talos/tests/devtools/addon/content/pages/
+testing/talos/talos/tests/dromaeo/
+testing/talos/talos/tests/v8_7/
+testing/talos/talos/tests/kraken/
 # Runing Talos may extract data here, see bug 1435677.
-testing/talos/talos/tests/tp5n/**
-# Raptor third party
-testing/raptor/raptor/playback/scripts/catapult/**
+testing/talos/talos/tests/tp5n/
 
-testing/web-platform/**
-testing/xpcshell/moz-http2/**
-testing/xpcshell/node-http2/**
-testing/xpcshell/dns-packet/**
-testing/xpcshell/node-ip/**
+testing/web-platform/
+testing/xpcshell/moz-http2/
+testing/xpcshell/node-http2/
+testing/xpcshell/dns-packet/
+testing/xpcshell/node-ip/
 
 
 # Third party.
-third_party/**
+third_party/
 
 # toolkit/ exclusions
 
@@ -338,7 +339,7 @@ toolkit/modules/AppConstants.jsm
 toolkit/modules/tests/xpcshell/test_task.js
 
 # Third party
-toolkit/modules/third_party/**
+toolkit/modules/third_party/
 
 tools/tryselect/selectors/chooser/templates/chooser.html
 
diff --git a/.eslintrc.js b/.eslintrc.js
index 205c3837d6..fcb8b911c2 100644
--- a/.eslintrc.js
+++ b/.eslintrc.js
@@ -194,23 +194,18 @@ module.exports = {
       "mozilla/reject-importGlobalProperties": "off",
       "mozilla/no-arbitrary-setTimeout": "off",
       "mozilla/no-define-cc-etc": "off",
-      "mozilla/no-useless-parameters": "off",
-      "mozilla/no-useless-run-test": "off",
       "mozilla/use-chromeutils-generateqi": "off",
-      "mozilla/use-chromeutils-import": "off",
       "mozilla/use-default-preference-values": "off",
       "mozilla/use-includes-instead-of-indexOf": "off",
       "mozilla/use-services": "off",
       "mozilla/use-ownerGlobal": "off",
       "complexity": "off",
       "consistent-return": "off",
-      "dot-notation": "off",
       "no-array-constructor": "off",
       "no-caller": "off",
       "no-cond-assign": "off",
       "no-extra-boolean-cast": "off",
       "no-eval": "off",
-      "no-else-return": "off",
       "no-func-assign": "off",
       "no-global-assign": "off",
       "no-implied-eval": "off",
@@ -326,5 +321,49 @@ module.exports = {
       "no-useless-return": "off",
       "no-with": "off",
     }
+  }, {
+    "files": [
+      "browser/components/extensions/ExtensionControlledPopup.jsm",
+      "browser/components/extensions/test/browser/browser_ext_devtools_network.js",
+      "browser/components/extensions/test/browser/browser_ext_tabs_zoom.js",
+      "browser/components/places/tests/browser/browser_bookmarksProperties.js",
+      "browser/components/preferences/in-content/tests/browser_extension_controlled.js",
+      "browser/extensions/formautofill/FormAutofillParent.jsm",
+      "browser/tools/mozscreenshots/head.js",
+      "devtools/client/aboutdebugging/test/browser/helper-addons.js",
+      "devtools/client/inspector/animation/animation.js",
+      "devtools/client/inspector/changes/ChangesView.js",
+      "devtools/client/inspector/markup/test/helper_screenshot_node.js",
+      "devtools/client/performance/modules/widgets/graphs.js",
+      "devtools/client/scratchpad/scratchpad.js",
+      "devtools/client/webconsole/webconsole-wrapper.js",
+      "devtools/server/tests/unit/test_breakpoint-17.js",
+      "devtools/shared/adb/adb-process.js",
+      "devtools/shared/fronts/webconsole.js",
+      "dom/l10n/tests/mochitest/document_l10n/non-system-principal/test.html",
+      "dom/payments/test/test_basiccard.html",
+      "dom/payments/test/test_bug1478740.html",
+      "dom/payments/test/test_canMakePayment.html",
+      "dom/payments/test/test_closePayment.html",
+      "dom/payments/test/test_showPayment.html",
+      "dom/tests/browser/browser_persist_cookies.js",
+      "dom/tests/browser/browser_persist_mixed_content_image.js",
+      "netwerk/test/unit/test_http2-proxy.js",
+      "toolkit/components/contentprefs/ContentPrefService2.jsm",
+      "toolkit/components/extensions/ExtensionShortcuts.jsm",
+      "toolkit/components/extensions/ExtensionTestCommon.jsm",
+      "toolkit/components/extensions/test/browser/browser_ext_themes_dynamic_getCurrent.js",
+      "toolkit/components/extensions/test/browser/browser_ext_themes_warnings.js",
+      "toolkit/components/passwordmgr/test/browser/browser_autocomplete_footer.js",
+      "toolkit/components/remotebrowserutils/tests/browser/browser_httpResponseProcessSelection.js",
+      "toolkit/components/satchel/FormHistory.jsm",
+      "toolkit/content/tests/browser/browser_findbar.js",
+      "toolkit/modules/NewTabUtils.jsm",
+      "toolkit/mozapps/extensions/test/browser/browser_CTP_plugins.js",
+      "toolkit/mozapps/extensions/test/browser/head.js",
+    ],
+    "rules": {
+      "no-async-promise-executor": "off",
+    }
   }]
 };
diff --git a/.gitignore b/.gitignore
index 305459caa0..96ec746368 100644
--- a/.gitignore
+++ b/.gitignore
@@ -44,8 +44,6 @@ security/manager/.nss.checkout
 /gecko.log
 
 # Ignore newtab component build assets
-browser/components/newtab/bin/prerender.js
-browser/components/newtab/bin/prerender.js.map
 browser/components/newtab/data/locales.json
 browser/components/newtab/logs/
 
diff --git a/.prettierignore b/.prettierignore
index cf1d22586e..57a9b5d24c 100644
--- a/.prettierignore
+++ b/.prettierignore
@@ -15,10 +15,6 @@ browser/branding/nightly/pref/firefox-branding.js
 browser/branding/official/pref/firefox-branding.js
 browser/branding/unofficial/pref/firefox-branding.js
 devtools/client/preferences/debugger.js
-devtools/client/preferences/devtools-client.js
-devtools/client/webide/preferences/webide.js
-devtools/shared/preferences/devtools-shared.js
-devtools/startup/preferences/devtools-startup.js
 extensions/pref/autoconfig/test/unit/autoconfig.js
 mobile/android/app/geckoview-prefs.js
 mobile/android/app/mobile.js
diff --git a/Cargo.lock b/Cargo.lock
index ea51ecc9b4..efe5d73b74 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1,15 +1,5 @@
 # This file is automatically @generated by Cargo.
 # It is not intended for manual editing.
-[[package]]
-name = "Inflector"
-version = "0.11.4"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "fe438c63458706e03479442743baae6c88256498e6431708f6dfc520a26515d3"
-dependencies = [
- "lazy_static",
- "regex",
-]
-
 [[package]]
 name = "adler32"
 version = "1.0.3"
@@ -25,15 +15,6 @@ dependencies = [
  "memchr",
 ]
 
-[[package]]
-name = "ansi_term"
-version = "0.11.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ee49baf6cb617b853aa8d93bf420db2383fab46d314482ca2803b40d5fde979b"
-dependencies = [
- "winapi 0.3.7",
-]
-
 [[package]]
 name = "app_units"
 version = "0.7.0"
@@ -212,19 +193,6 @@ version = "0.1.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "88ceb0d16c4fd0e42876e298d7d3ce3780dd9ebdcbe4199816a32c77e08597ff"
 
-[[package]]
-name = "binast"
-version = "0.2.0"
-dependencies = [
- "Inflector",
- "binjs_meta",
- "clap",
- "env_logger",
- "itertools",
- "log",
- "yaml-rust",
-]
-
 [[package]]
 name = "bincode"
 version = "1.2.1"
@@ -255,18 +223,6 @@ dependencies = [
  "shlex",
 ]
 
-[[package]]
-name = "binjs_meta"
-version = "0.5.4"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d535cc5246fd9035268770420afd76c05f87e68b83ebed0ac94e8258e88fc353"
-dependencies = [
- "Inflector",
- "itertools",
- "log",
- "weedle",
-]
-
 [[package]]
 name = "bit-vec"
 version = "0.5.1"
@@ -516,14 +472,11 @@ version = "2.31.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f0f16b89cbb9ee36d87483dc939fe9f1e13c05898d56d7b230a0d4dff033a536"
 dependencies = [
- "ansi_term",
- "atty",
  "bitflags",
  "strsim",
  "term_size",
  "textwrap",
  "unicode-width",
- "vec_map",
 ]
 
 [[package]]
@@ -750,9 +703,9 @@ dependencies = [
 
 [[package]]
 name = "cssparser"
-version = "0.27.2"
+version = "0.28.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "754b69d351cdc2d8ee09ae203db831e005560fc6030da058f86ad60c92a9cb0a"
+checksum = "809d22aba9ffd53e9028f2d37261f1826ef613d0e96b1a5ddeefa97cde82bcca"
 dependencies = [
  "cssparser-macros",
  "dtoa-short",
@@ -1726,12 +1679,6 @@ dependencies = [
  "safemem",
 ]
 
-[[package]]
-name = "linked-hash-map"
-version = "0.5.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "70fb39025bc7cdd76305867c4eccf2f2dcf6e9a57f5b21a93e1c2d86cd03ec9e"
-
 [[package]]
 name = "lmdb-rkv"
 version = "0.14.0"
@@ -2476,6 +2423,7 @@ dependencies = [
  "goblin",
  "memmap",
  "object",
+ "rustc-demangle",
  "thin-vec",
  "uuid",
 ]
@@ -3733,12 +3681,6 @@ version = "0.2.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9e0a7d8bed3178a8fb112199d466eeca9ed09a14ba8ad67718179b4fd5487d0b"
 
-[[package]]
-name = "vec_map"
-version = "0.8.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "887b5b631c2ad01628bbbaa7dd4c869f80d3186688f8d0b6f58774fbe324988c"
-
 [[package]]
 name = "version_check"
 version = "0.9.1"
@@ -3922,15 +3864,6 @@ dependencies = [
  "url",
 ]
 
-[[package]]
-name = "weedle"
-version = "0.11.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8a7d4f9feb723a800d8f7b74edc9fa44ff35cb0b2ec64886714362f423427f37"
-dependencies = [
- "nom",
-]
-
 [[package]]
 name = "winapi"
 version = "0.2.8"
@@ -4086,15 +4019,6 @@ dependencies = [
  "xpcom",
 ]
 
-[[package]]
-name = "yaml-rust"
-version = "0.4.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "95acf0db5515d07da9965ec0e0ba6cc2d825e2caeb7303b66ca441729801254e"
-dependencies = [
- "linked-hash-map",
-]
-
 [[package]]
 name = "zip"
 version = "0.4.2"
diff --git a/Cargo.toml b/Cargo.toml
index a21e00fda0..062b1f1259 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -9,7 +9,6 @@ members = [
   "js/src/rust",
   "js/src/wasm/cranelift",
   "js/rust",
-  "js/src/frontend/binast", # Code generator.
   "testing/geckodriver",
   "toolkit/crashreporter/rust",
   "toolkit/library/gtest/rust",
diff --git a/README.md b/README.md
index 02a8c8bbee..29601686a9 100644
--- a/README.md
+++ b/README.md
@@ -35,3 +35,10 @@ Then report like for site 'x' is missing feature 'y'
 **YOU MAY DONATE**
 
 But only by crypto [Look here](https://github.com/Feodor2/Mypal68/issues/84)
+
+
+**MY MIRROR PAGES**
+
+https://codeberg.org/Theodor2/Mypal68
+https://notabug.org/Theodor/Mypal68
+
diff --git a/accessible/base/EventQueue.cpp b/accessible/base/EventQueue.cpp
index a169686d49..26486e1aa8 100644
--- a/accessible/base/EventQueue.cpp
+++ b/accessible/base/EventQueue.cpp
@@ -267,8 +267,7 @@ void EventQueue::CoalesceSelChangeEvents(AccSelChangeEvent* aTailEvent,
 
 void EventQueue::ProcessEventQueue() {
   // Process only currently queued events.
-  nsTArray<RefPtr<AccEvent> > events;
-  events.SwapElements(mEvents);
+  const nsTArray<RefPtr<AccEvent> > events = std::move(mEvents);
 
   uint32_t eventCount = events.Length();
 #ifdef A11Y_LOG
diff --git a/accessible/generic/Accessible.cpp b/accessible/generic/Accessible.cpp
index 1ff146a7bb..632a4bc2c2 100644
--- a/accessible/generic/Accessible.cpp
+++ b/accessible/generic/Accessible.cpp
@@ -830,7 +830,7 @@ nsresult Accessible::HandleAccEvent(AccEvent* aEvent) {
     nsAutoCString strMarker;
     strMarker.AppendLiteral("A11y Event - ");
     strMarker.Append(strEventType);
-    profiler_add_marker(strMarker.get(), JS::ProfilingCategoryPair::OTHER);
+    PROFILER_ADD_MARKER(strMarker.get(), OTHER);
   }
 #endif
 
diff --git a/accessible/ipc/other/DocAccessibleChild.cpp b/accessible/ipc/other/DocAccessibleChild.cpp
index a430c5dac8..fe8f1a859c 100644
--- a/accessible/ipc/other/DocAccessibleChild.cpp
+++ b/accessible/ipc/other/DocAccessibleChild.cpp
@@ -173,7 +173,7 @@ static void AddRelation(Accessible* aAcc, RelationType aType,
   if (!targets.IsEmpty()) {
     RelationTargets* newRelation = aTargets->AppendElement(
         RelationTargets(static_cast<uint32_t>(aType), nsTArray<uint64_t>()));
-    newRelation->Targets().SwapElements(targets);
+    newRelation->Targets() = std::move(targets);
   }
 }
 
diff --git a/browser/actors/ContextMenuChild.jsm b/browser/actors/ContextMenuChild.jsm
index 999dfe968f..ffb43e5e4e 100644
--- a/browser/actors/ContextMenuChild.jsm
+++ b/browser/actors/ContextMenuChild.jsm
@@ -586,9 +586,17 @@ class ContextMenuChild extends ActorChild {
     let referrerInfo = Cc["@mozilla.org/referrer-info;1"].createInstance(
       Ci.nsIReferrerInfo
     );
-    referrerInfo.initWithElement(
-      context.onLink ? context.link : aEvent.composedTarget
-    );
+    referrerInfo.initWithElement(aEvent.composedTarget);
+
+    // In the case "onLink" we may have to send link referrerInfo to use in
+    // _openLinkInParameters
+    let linkReferrerInfo = null;
+    if (context.onLink) {
+      linkReferrerInfo = Cc["@mozilla.org/referrer-info;1"].createInstance(
+        Ci.nsIReferrerInfo
+      );
+      linkReferrerInfo.initWithElement(context.link);
+    }
 
     let targetAsCPOW = context.target;
     if (targetAsCPOW) {
@@ -652,17 +660,12 @@ class ContextMenuChild extends ActorChild {
       );
     }
 
-    // In the case "onLink" we may have to send target referrerInfo. This object
-    // may be used to in saveMedia function.
-    if (context.onLink) {
-      let targetReferrerInfo = Cc[
-        "@mozilla.org/referrer-info;1"
-      ].createInstance(Ci.nsIReferrerInfo);
-
-      targetReferrerInfo.initWithElement(aEvent.composedTarget);
-      data.targetReferrerInfo = E10SUtils.serializeReferrerInfo(
-        targetReferrerInfo
-      );
+    if (linkReferrerInfo) {
+      if (isRemote) {
+        data.linkReferrerInfo = E10SUtils.serializeReferrerInfo(linkReferrerInfo);
+      } else {
+        data.linkReferrerInfo = linkReferrerInfo;
+      }
     }
 
     Services.obs.notifyObservers(
diff --git a/browser/app/profile/mypal.js b/browser/app/profile/mypal.js
index 275b4a4f05..5827c0bc07 100644
--- a/browser/app/profile/mypal.js
+++ b/browser/app/profile/mypal.js
@@ -1715,3 +1715,413 @@ pref("identity.fxaccounts.toolbar.accessed", false);
 #else
   pref("corroborator.enabled", true);
 #endif
+
+// Disable WebIDE and ConnectPage by default (Bug 1539451)
+pref("devtools.webide.enabled", false);
+pref("devtools.connectpage.enabled", false);
+
+// Toolbox preferences
+pref("devtools.toolbox.footer.height", 250);
+pref("devtools.toolbox.sidebar.width", 500);
+pref("devtools.toolbox.host", "bottom");
+pref("devtools.toolbox.previousHost", "right");
+pref("devtools.toolbox.selectedTool", "inspector");
+pref("devtools.toolbox.sideEnabled", true);
+pref("devtools.toolbox.zoomValue", "1");
+pref("devtools.toolbox.splitconsoleEnabled", false);
+pref("devtools.toolbox.splitconsoleHeight", 100);
+pref("devtools.toolbox.tabsOrder", "");
+
+// Toolbox Button preferences
+pref("devtools.command-button-pick.enabled", true);
+pref("devtools.command-button-frames.enabled", true);
+pref("devtools.command-button-splitconsole.enabled", true);
+pref("devtools.command-button-paintflashing.enabled", false);
+pref("devtools.command-button-scratchpad.enabled", false);
+pref("devtools.command-button-responsive.enabled", true);
+pref("devtools.command-button-screenshot.enabled", false);
+pref("devtools.command-button-rulers.enabled", false);
+pref("devtools.command-button-measure.enabled", false);
+pref("devtools.command-button-noautohide.enabled", false);
+
+// Inspector preferences
+// Enable the Inspector
+pref("devtools.inspector.enabled", true);
+// What was the last active sidebar in the inspector
+pref("devtools.inspector.activeSidebar", "layoutview");
+pref("devtools.inspector.remote", false);
+
+// Enable the 3 pane mode in the inspector
+pref("devtools.inspector.three-pane-enabled", true);
+// Enable the 3 pane mode in the chrome inspector
+pref("devtools.inspector.chrome.three-pane-enabled", false);
+// Collapse pseudo-elements by default in the rule-view
+pref("devtools.inspector.show_pseudo_elements", false);
+// The default size for image preview tooltips in the rule-view/computed-view/markup-view
+pref("devtools.inspector.imagePreviewTooltipSize", 300);
+// Enable user agent style inspection in rule-view
+pref("devtools.inspector.showUserAgentStyles", false);
+// Show all native anonymous content
+pref("devtools.inspector.showAllAnonymousContent", false);
+// Show user agent shadow roots
+pref("devtools.inspector.showUserAgentShadowRoots", false);
+// Enable the new Rules View
+pref("devtools.inspector.new-rulesview.enabled", false);
+
+// Grid highlighter preferences
+pref("devtools.gridinspector.gridOutlineMaxColumns", 50);
+pref("devtools.gridinspector.gridOutlineMaxRows", 50);
+pref("devtools.gridinspector.showGridAreas", false);
+pref("devtools.gridinspector.showGridLineNumbers", false);
+pref("devtools.gridinspector.showInfiniteLines", false);
+// Max number of grid highlighters that can be displayed
+pref("devtools.gridinspector.maxHighlighters", 3);
+
+// Whether or not the box model panel is opened in the layout view
+pref("devtools.layout.boxmodel.opened", true);
+// Whether or not the flexbox panel is opened in the layout view
+pref("devtools.layout.flexbox.opened", true);
+// Whether or not the grid inspector panel is opened in the layout view
+pref("devtools.layout.grid.opened", true);
+
+// Enable hovering Box Model values and jumping to their source CSS rule in the
+// rule-view.
+#if defined(NIGHTLY_BUILD)
+  pref("devtools.layout.boxmodel.highlightProperty", true);
+#else
+  pref("devtools.layout.boxmodel.highlightProperty", false);
+#endif
+
+// By how many times eyedropper will magnify pixels
+pref("devtools.eyedropper.zoom", 6);
+
+// Enable to collapse attributes that are too long.
+pref("devtools.markup.collapseAttributes", true);
+// Length to collapse attributes
+pref("devtools.markup.collapseAttributeLength", 120);
+// Whether to auto-beautify the HTML on copy.
+pref("devtools.markup.beautifyOnCopy", false);
+// Whether or not the DOM mutation breakpoints context menu are enabled in the
+// markup view.
+pref("devtools.markup.mutationBreakpoints.enabled", true);
+
+// DevTools default color unit
+pref("devtools.defaultColorUnit", "authored");
+
+// Enable the Memory tools
+pref("devtools.memory.enabled", true);
+
+pref("devtools.memory.custom-census-displays", "{}");
+pref("devtools.memory.custom-label-displays", "{}");
+pref("devtools.memory.custom-tree-map-displays", "{}");
+
+pref("devtools.memory.max-individuals", 1000);
+pref("devtools.memory.max-retaining-paths", 10);
+
+// Enable the Performance tools
+pref("devtools.performance.enabled", true);
+
+// The default Performance UI settings
+pref("devtools.performance.memory.sample-probability", "0.05");
+// Can't go higher than this without causing internal allocation overflows while
+// serializing the allocations data over the RDP.
+pref("devtools.performance.memory.max-log-length", 125000);
+pref("devtools.performance.timeline.hidden-markers",
+  "[\"Composite\",\"CompositeForwardTransaction\"]");
+pref("devtools.performance.profiler.buffer-size", 10000000);
+pref("devtools.performance.profiler.sample-frequency-hz", 1000);
+pref("devtools.performance.ui.invert-call-tree", true);
+pref("devtools.performance.ui.invert-flame-graph", false);
+pref("devtools.performance.ui.flatten-tree-recursion", true);
+pref("devtools.performance.ui.show-platform-data", false);
+pref("devtools.performance.ui.show-idle-blocks", true);
+pref("devtools.performance.ui.enable-memory", false);
+pref("devtools.performance.ui.enable-allocations", false);
+pref("devtools.performance.ui.enable-framerate", true);
+pref("devtools.performance.ui.show-jit-optimizations", false);
+pref("devtools.performance.ui.show-triggers-for-gc-types",
+  "TOO_MUCH_MALLOC ALLOC_TRIGGER LAST_DITCH EAGER_ALLOC_TRIGGER");
+
+// Temporary pref disabling memory flame views
+// TODO remove once we have flame charts via bug 1148663
+pref("devtools.performance.ui.enable-memory-flame", false);
+
+// Enable experimental options in the UI only in Nightly
+#if defined(NIGHTLY_BUILD)
+  pref("devtools.performance.ui.experimental", true);
+#else
+  pref("devtools.performance.ui.experimental", false);
+#endif
+
+// Preferences for the new performance panel. This pref configures the base URL
+// for the profiler.firefox.com instance to use. This is useful so that a
+// developer can change it while working on profiler.firefox.com, or in tests.
+// This isn't exposed directly to the user.
+pref("devtools.performance.recording.ui-base-url", "https://profiler.firefox.com");
+
+// A JSON array of strings, where each string is a file path to an objdir on
+// the host machine. This is used in order to look up symbol information from
+// build artifacts of local builds.
+pref("devtools.performance.recording.objdirs", "[]");
+
+// The default cache UI setting
+pref("devtools.cache.disabled", false);
+
+// The default service workers UI setting
+pref("devtools.serviceWorkers.testing.enabled", false);
+
+// Enable the Network Monitor
+pref("devtools.netmonitor.enabled", true);
+
+// Enable the Application panel
+pref("devtools.application.enabled", false);
+
+// The default Network Monitor UI settings
+pref("devtools.netmonitor.panes-network-details-width", 550);
+pref("devtools.netmonitor.panes-network-details-height", 450);
+pref("devtools.netmonitor.filters", "[\"all\"]");
+pref("devtools.netmonitor.visibleColumns",
+  "[\"status\",\"method\",\"domain\",\"file\",\"cause\",\"type\",\"transferred\",\"contentSize\",\"waterfall\"]"
+);
+pref("devtools.netmonitor.columnsData",
+  '[{"name":"status","minWidth":30,"width":5}, {"name":"method","minWidth":30,"width":5}, {"name":"domain","minWidth":30,"width":10}, {"name":"file","minWidth":30,"width":25}, {"name":"url","minWidth":30,"width":25}, {"name":"cause","minWidth":30,"width":10},{"name":"type","minWidth":30,"width":5},{"name":"transferred","minWidth":30,"width":10},{"name":"contentSize","minWidth":30,"width":5},{"name":"waterfall","minWidth":150,"width":25}]');
+pref("devtools.netmonitor.ws.payload-preview-height", 128);
+pref("devtools.netmonitor.ws.visibleColumns",
+  '["data", "time"]'
+);
+pref("devtools.netmonitor.ws.displayed-frames.limit", 500);
+
+pref("devtools.netmonitor.response.ui.limit", 10240);
+
+// Save request/response bodies yes/no.
+pref("devtools.netmonitor.saveRequestAndResponseBodies", true);
+
+// The default Network monitor HAR export setting
+pref("devtools.netmonitor.har.defaultLogDir", "");
+pref("devtools.netmonitor.har.defaultFileName", "%hostname_Archive [%date]");
+pref("devtools.netmonitor.har.jsonp", false);
+pref("devtools.netmonitor.har.jsonpCallback", "");
+pref("devtools.netmonitor.har.includeResponseBodies", true);
+pref("devtools.netmonitor.har.compress", false);
+pref("devtools.netmonitor.har.forceExport", false);
+pref("devtools.netmonitor.har.pageLoadedTimeout", 1500);
+pref("devtools.netmonitor.har.enableAutoExportToFile", false);
+
+// Enable WebSocket monitoring in Nightly builds.
+#if defined(NIGHTLY_BUILD)
+  pref("devtools.netmonitor.features.webSockets", true);
+#else
+  pref("devtools.netmonitor.features.webSockets", false);
+#endif
+
+// Scratchpad settings
+// - recentFileMax: The maximum number of recently-opened files
+//                  stored. Setting this preference to 0 will not
+//                  clear any recent files, but rather hide the
+//                  'Open Recent'-menu.
+// - lineNumbers: Whether to show line numbers or not.
+// - wrapText: Whether to wrap text or not.
+// - showTrailingSpace: Whether to highlight trailing space or not.
+// - editorFontSize: Editor font size configuration.
+// - enableAutocompletion: Whether to enable JavaScript autocompletion.
+pref("devtools.scratchpad.recentFilesMax", 10);
+pref("devtools.scratchpad.lineNumbers", true);
+pref("devtools.scratchpad.wrapText", false);
+pref("devtools.scratchpad.showTrailingSpace", false);
+pref("devtools.scratchpad.editorFontSize", 12);
+pref("devtools.scratchpad.enableAutocompletion", true);
+
+// Enable the Storage Inspector
+pref("devtools.storage.enabled", true);
+
+// Enable the Style Editor.
+pref("devtools.styleeditor.enabled", true);
+pref("devtools.styleeditor.autocompletion-enabled", true);
+pref("devtools.styleeditor.showMediaSidebar", true);
+pref("devtools.styleeditor.mediaSidebarWidth", 238);
+pref("devtools.styleeditor.navSidebarWidth", 245);
+pref("devtools.styleeditor.transitions", true);
+
+// Screenshot Option Settings.
+pref("devtools.screenshot.clipboard.enabled", false);
+pref("devtools.screenshot.audio.enabled", true);
+
+// Enable Scratchpad
+pref("devtools.scratchpad.enabled", false);
+
+// Make sure the DOM panel is hidden by default
+pref("devtools.dom.enabled", false);
+
+// Enable the Accessibility panel.
+pref("devtools.accessibility.enabled", true);
+
+// Web console filters
+pref("devtools.webconsole.filter.error", true);
+pref("devtools.webconsole.filter.warn", true);
+pref("devtools.webconsole.filter.info", true);
+pref("devtools.webconsole.filter.log", true);
+pref("devtools.webconsole.filter.debug", true);
+pref("devtools.webconsole.filter.css", false);
+pref("devtools.webconsole.filter.net", false);
+pref("devtools.webconsole.filter.netxhr", false);
+
+// Webconsole autocomplete preference
+pref("devtools.webconsole.input.autocomplete",true);
+
+// Browser console filters
+pref("devtools.browserconsole.filter.error", true);
+pref("devtools.browserconsole.filter.warn", true);
+pref("devtools.browserconsole.filter.info", true);
+pref("devtools.browserconsole.filter.log", true);
+pref("devtools.browserconsole.filter.debug", true);
+pref("devtools.browserconsole.filter.css", false);
+pref("devtools.browserconsole.filter.net", false);
+pref("devtools.browserconsole.filter.netxhr", false);
+
+// Max number of inputs to store in web console history.
+pref("devtools.webconsole.inputHistoryCount", 300);
+
+// Persistent logging: |true| if you want the relevant tool to keep all of the
+// logged messages after reloading the page, |false| if you want the output to
+// be cleared each time page navigation happens.
+pref("devtools.webconsole.persistlog", false);
+pref("devtools.netmonitor.persistlog", false);
+
+// Web Console timestamp: |true| if you want the logs and instructions
+// in the Web Console to display a timestamp, or |false| to not display
+// any timestamps.
+pref("devtools.webconsole.timestampMessages", false);
+
+// Enable the webconsole sidebar toggle in Nightly builds.
+#if defined(NIGHTLY_BUILD)
+  pref("devtools.webconsole.sidebarToggle", true);
+#else
+  pref("devtools.webconsole.sidebarToggle", false);
+#endif
+
+// Enable editor mode in the console in Nightly builds.
+#if defined(NIGHTLY_BUILD)
+  pref("devtools.webconsole.features.editor", true);
+#else
+  pref("devtools.webconsole.features.editor", false);
+#endif
+
+// Saved editor mode state in the console.
+pref("devtools.webconsole.input.editor", false);
+
+// Editor width for webconsole and browserconsole
+pref("devtools.webconsole.input.editorWidth", 0);
+pref("devtools.browserconsole.input.editorWidth", 0);
+
+// Disable the new performance recording panel by default
+pref("devtools.performance.new-panel-enabled", false);
+
+// Enable message grouping in the console, true by default
+pref("devtools.webconsole.groupWarningMessages", true);
+
+// Saved state of the Display content messages checkbox in the browser console.
+pref("devtools.browserconsole.contentMessages", false);
+
+// Enable client-side mapping service for source maps
+pref("devtools.source-map.client-service.enabled", true);
+
+// The number of lines that are displayed in the web console.
+pref("devtools.hud.loglimit", 10000);
+
+// The developer tools editor configuration:
+// - tabsize: how many spaces to use when a Tab character is displayed.
+// - expandtab: expand Tab characters to spaces.
+// - keymap: which keymap to use (can be 'default', 'emacs' or 'vim')
+// - autoclosebrackets: whether to permit automatic bracket/quote closing.
+// - detectindentation: whether to detect the indentation from the file
+// - enableCodeFolding: Whether to enable code folding or not.
+pref("devtools.editor.tabsize", 2);
+pref("devtools.editor.expandtab", true);
+pref("devtools.editor.keymap", "default");
+pref("devtools.editor.autoclosebrackets", true);
+pref("devtools.editor.detectindentation", true);
+pref("devtools.editor.enableCodeFolding", true);
+pref("devtools.editor.autocomplete", true);
+
+// The angle of the viewport.
+pref("devtools.responsive.viewport.angle", 0);
+// The width of the viewport.
+pref("devtools.responsive.viewport.width", 320);
+// The height of the viewport.
+pref("devtools.responsive.viewport.height", 480);
+// The pixel ratio of the viewport.
+pref("devtools.responsive.viewport.pixelRatio", 0);
+// Whether or not the viewports are left aligned.
+pref("devtools.responsive.leftAlignViewport.enabled", false);
+// Whether to reload when touch simulation is toggled
+pref("devtools.responsive.reloadConditions.touchSimulation", false);
+// Whether to reload when user agent is changed
+pref("devtools.responsive.reloadConditions.userAgent", false);
+// Whether to show the notification about reloading to apply emulation
+pref("devtools.responsive.reloadNotification.enabled", true);
+// Whether or not touch simulation is enabled.
+pref("devtools.responsive.touchSimulation.enabled", false);
+// Whether or not meta viewport is enabled, if and only if touchSimulation
+// is also enabled.
+pref("devtools.responsive.metaViewport.enabled", false);
+// The user agent of the viewport.
+pref("devtools.responsive.userAgent", "");
+
+// Whether to show the settings onboarding tooltip only in release or beta
+// builds.
+#if defined(RELEASE_OR_BETA)
+  pref("devtools.responsive.show-setting-tooltip", true);
+#else
+  pref("devtools.responsive.show-setting-tooltip", false);
+#endif
+// Show the custom user agent input in Nightly builds.
+#if defined(NIGHTLY_BUILD)
+  pref("devtools.responsive.showUserAgentInput", true);
+#else
+  pref("devtools.responsive.showUserAgentInput", false);
+#endif
+
+// Show tab debug targets for This Firefox (on by default for local builds).
+#ifdef MOZILLA_OFFICIAL
+  pref("devtools.aboutdebugging.local-tab-debugging", false);
+#else
+  pref("devtools.aboutdebugging.local-tab-debugging", true);
+#endif
+
+// Show process debug targets.
+pref("devtools.aboutdebugging.process-debugging", true);
+// Stringified array of network locations that users can connect to.
+pref("devtools.aboutdebugging.network-locations", "[]");
+// Debug target pane collapse/expand settings.
+pref("devtools.aboutdebugging.collapsibilities.installedExtension", false);
+pref("devtools.aboutdebugging.collapsibilities.otherWorker", false);
+pref("devtools.aboutdebugging.collapsibilities.serviceWorker", false);
+pref("devtools.aboutdebugging.collapsibilities.sharedWorker", false);
+pref("devtools.aboutdebugging.collapsibilities.tab", false);
+pref("devtools.aboutdebugging.collapsibilities.temporaryExtension", false);
+
+// about:debugging: only show system and hidden extensions in local builds by
+// default.
+#ifdef MOZILLA_OFFICIAL
+  pref("devtools.aboutdebugging.showHiddenAddons", false);
+#else
+  pref("devtools.aboutdebugging.showHiddenAddons", true);
+#endif
+
+// Map top-level await expressions in the console
+pref("devtools.debugger.features.map-await-expression", true);
+
+// Disable autohide for DevTools popups and tooltips.
+// This is currently not exposed by any UI to avoid making
+// about:devtools-toolbox tabs unusable by mistake.
+pref("devtools.popup.disable_autohide", false);
+
+pref("devtools.webide.templatesURL", "https://code.cdn.mozilla.net/templates/list.json");
+pref("devtools.webide.autoinstallADBExtension", true);
+pref("devtools.webide.autoConnectRuntime", true);
+pref("devtools.webide.restoreLastProject", true);
+pref("devtools.webide.enableLocalRuntime", false);
+pref("devtools.webide.lastConnectedRuntime", "");
+pref("devtools.webide.lastSelectedProject", "");
+pref("devtools.webide.zoom", "1");
+pref("devtools.webide.busyTimeout", 10000);
diff --git a/browser/app/winlauncher/test/moz.build b/browser/app/winlauncher/test/moz.build
index abd93ad82b..a2fc1706cd 100644
--- a/browser/app/winlauncher/test/moz.build
+++ b/browser/app/winlauncher/test/moz.build
@@ -25,6 +25,3 @@ if CONFIG['CC_TYPE'] in ('gcc', 'clang'):
     LDFLAGS += [
         '-municode',
     ]
-
-if CONFIG['CC_TYPE'] == 'clang-cl':
-    AllowCompilerWarnings()  # workaround for bug 1090497
diff --git a/browser/base/content/aboutRestartRequired.js b/browser/base/content/aboutRestartRequired.js
index 753664f427..d9ad24f6dd 100644
--- a/browser/base/content/aboutRestartRequired.js
+++ b/browser/base/content/aboutRestartRequired.js
@@ -32,3 +32,8 @@ var AboutRestartRequired = {
 };
 
 AboutRestartRequired.init();
+
+let restartButton = document.getElementById("restart");
+restartButton.onclick = function() {
+  AboutRestartRequired.restart();
+};
diff --git a/browser/base/content/aboutRestartRequired.xhtml b/browser/base/content/aboutRestartRequired.xhtml
index 02e2296d75..6db21758a1 100644
--- a/browser/base/content/aboutRestartRequired.xhtml
+++ b/browser/base/content/aboutRestartRequired.xhtml
@@ -6,6 +6,7 @@
 
 <html xmlns="http://www.w3.org/1999/xhtml">
   <head>
+    <meta http-equiv="Content-Security-Policy" content="default-src chrome:" />
     <title data-l10n-id="restart-required-title"></title>
     <link rel="stylesheet" type="text/css" media="all"
           href="chrome://browser/skin/aboutRestartRequired.css"/>
@@ -33,8 +34,7 @@
       </div>
       <!-- Restart Button -->
       <div id="restartButtonContainer" class="button-container">
-        <button id="restart" data-l10n-id="restart-button-label" class="primary" autocomplete="off"
-                onclick="AboutRestartRequired.restart();"></button>
+        <button id="restart" data-l10n-id="restart-button-label" class="primary" autocomplete="off"></button>
       </div>
     </div>
   </body>
diff --git a/browser/base/content/browser.js b/browser/base/content/browser.js
index a3d95d2704..b03d2f10b1 100644
--- a/browser/base/content/browser.js
+++ b/browser/base/content/browser.js
@@ -3381,6 +3381,7 @@ function losslessDecodeURI(aURI) {
   // This includes all bidirectional formatting characters.
   // (RFC 3987 sections 3.2 and 4.1 paragraph 6)
   value = value.replace(
+    // eslint-disable-next-line no-misleading-character-class
     /[\u00ad\u034f\u061c\u115f-\u1160\u17b4-\u17b5\u180b-\u180d\u200b\u200e-\u200f\u202a-\u202e\u2060-\u206f\u3164\ufe00-\ufe0f\ufeff\uffa0\ufff0-\ufff8]|\ud834[\udd73-\udd7a]|[\udb40-\udb43][\udc00-\udfff]/g,
     encodeURIComponent
   );
@@ -9276,7 +9277,7 @@ var RestoreLastSessionObserver = {
     ) {
       Services.obs.addObserver(this, "sessionstore-last-session-cleared", true);
       goSetCommandEnabled("Browser:RestoreLastSession", true);
-    } else if (SessionStartup.isAutomaticRestoreEnabled()) {
+    } else if (SessionStore.willAutoRestore) {
       document
         .getElementById("Browser:RestoreLastSession")
         .setAttribute("hidden", true);
diff --git a/browser/base/content/nsContextMenu.js b/browser/base/content/nsContextMenu.js
index 292c489b1c..42f28da13e 100644
--- a/browser/base/content/nsContextMenu.js
+++ b/browser/base/content/nsContextMenu.js
@@ -44,7 +44,7 @@ function openContextMenu(aMessage) {
   let browser = aMessage.target;
   let spellInfo = data.spellInfo;
   let frameReferrerInfo = data.frameReferrerInfo;
-  let targetReferrerInfo = data.targetReferrerInfo;
+  let linkReferrerInfo = data.linkReferrerInfo;
 
   // ContextMenu.jsm sends us the target as a CPOW only so that
   // we can send that CPOW back down to the content process and
@@ -68,8 +68,8 @@ function openContextMenu(aMessage) {
       E10SUtils.deserializeReferrerInfo(frameReferrerInfo);
   }
 
-  if (targetReferrerInfo) {
-    targetReferrerInfo = E10SUtils.deserializeReferrerInfo(targetReferrerInfo);
+  if (linkReferrerInfo && data.isRemote) {
+    linkReferrerInfo = E10SUtils.deserializeReferrerInfo(linkReferrerInfo);
   }
 
   gContextMenuContentData = {
@@ -86,7 +86,7 @@ function openContextMenu(aMessage) {
     charSet: data.charSet,
     referrerInfo: E10SUtils.deserializeReferrerInfo(data.referrerInfo),
     frameReferrerInfo,
-    targetReferrerInfo,
+    linkReferrerInfo,
     contentType: data.contentType,
     contentDisposition: data.contentDisposition,
     frameOuterWindowID: data.frameOuterWindowID,
@@ -1094,7 +1094,9 @@ nsContextMenu.prototype = {
       params.frameOuterWindowID = this.frameOuterWindowID;
     }
 
-    let referrerInfo = gContextMenuContentData.referrerInfo;
+    let referrerInfo = this.onLink
+      ? gContextMenuContentData.linkReferrerInfo
+      : gContextMenuContentData.referrerInfo;
     // If we want to change userContextId, we must be sure that we don't
     // propagate the referrer.
     if (
@@ -1371,7 +1373,7 @@ nsContextMenu.prototype = {
     );
 
     // Cache this because we fetch the data async
-    let { targetReferrerInfo } = gContextMenuContentData;
+    let referrerInfo = gContextMenuContentData.referrerInfo;
 
     let onMessage = message => {
       mm.removeMessageListener(
@@ -1386,7 +1388,7 @@ nsContextMenu.prototype = {
         "SaveImageTitle",
         true, // bypass cache
         false, // don't skip prompt for where to save
-        targetReferrerInfo, // referrer info
+        referrerInfo, // referrer info
         null, // document
         null, // content type
         null, // content disposition
@@ -1672,6 +1674,10 @@ nsContextMenu.prototype = {
 
   // Save URL of clicked-on link.
   saveLink() {
+    let referrerInfo = this.onLink
+      ? gContextMenuContentData.linkReferrerInfo
+      : gContextMenuContentData.referrerInfo;
+
     let isContentWindowPrivate = this.isRemote
       ? this.ownerDoc.isPrivate
       : undefined;
@@ -1681,7 +1687,7 @@ nsContextMenu.prototype = {
       null,
       true,
       this.ownerDoc,
-      gContextMenuContentData.referrerInfo,
+      referrerInfo,
       this.frameOuterWindowID,
       this.linkDownload,
       isContentWindowPrivate
@@ -1701,7 +1707,7 @@ nsContextMenu.prototype = {
     let isContentWindowPrivate = this.isRemote
       ? this.ownerDoc.isPrivate
       : undefined;
-    let referrerInfo = gContextMenuContentData.targetReferrerInfo;
+    let referrerInfo = gContextMenuContentData.referrerInfo;
     let isPrivate = PrivateBrowsingUtils.isBrowserPrivate(this.browser);
     if (this.onCanvas) {
       // Bypass cache, since it's a data: URL.
diff --git a/browser/base/content/test/plugins/head.js b/browser/base/content/test/plugins/head.js
index b8de7f2d0b..ba667d350d 100644
--- a/browser/base/content/test/plugins/head.js
+++ b/browser/base/content/test/plugins/head.js
@@ -19,7 +19,7 @@ XPCOMUtils.defineLazyServiceGetters(this, {
 
 // Various tests in this directory may define gTestBrowser, to use as the
 // default browser under test in some of the functions below.
-/* global gTestBrowser */
+/* global gTestBrowser:true */
 
 /**
  * Waits a specified number of miliseconds.
diff --git a/browser/base/content/test/static/browser_all_files_referenced.js b/browser/base/content/test/static/browser_all_files_referenced.js
index b021c2c78f..0eaa393c36 100644
--- a/browser/base/content/test/static/browser_all_files_referenced.js
+++ b/browser/base/content/test/static/browser_all_files_referenced.js
@@ -32,8 +32,6 @@ var gExceptionPaths = [
 
   // https://github.com/mozilla/activity-stream/issues/3053
   "resource://activity-stream/data/content/tippytop/images/",
-  // https://github.com/mozilla/activity-stream/issues/3758
-  "resource://activity-stream/prerendered/",
 
   // browser/extensions/pdfjs/content/build/pdf.js#1999
   "resource://pdf.js/web/images/",
@@ -266,6 +264,11 @@ if (!isDevtools) {
   ]) {
     whitelist.add("resource://services-sync/engines/" + module);
   }
+  // resource://devtools/shared/worker/loader.js,
+  // resource://devtools/shared/builtin-modules.js
+  if (!AppConstants.ENABLE_REMOTE_AGENT) {
+    whitelist.add("resource://gre/modules/jsdebugger.jsm");
+  }
 }
 
 if (AppConstants.MOZ_CODE_COVERAGE) {
diff --git a/browser/base/content/test/static/browser_misused_characters_in_strings.js b/browser/base/content/test/static/browser_misused_characters_in_strings.js
index a9667b4feb..6bbefe0c74 100644
--- a/browser/base/content/test/static/browser_misused_characters_in_strings.js
+++ b/browser/base/content/test/static/browser_misused_characters_in_strings.js
@@ -281,13 +281,13 @@ add_task(async function checkAllTheFluents() {
   domParser.forceEnableDTD();
   for (let uri of uris) {
     let rawContents = await fetchFile(uri.spec);
-    let resource = FluentResource.fromString(rawContents);
+    let resource = new FluentResource(rawContents);
     if (!resource) {
       return;
     }
 
-    for (let [key, val] of resource) {
-      CheckError(domParser, uri, key, val);
+    for (let message of resource.body) {
+      CheckError(domParser, uri, message.id, message);
     }
   }
 });
diff --git a/browser/components/BrowserGlue.jsm b/browser/components/BrowserGlue.jsm
index 002ed6ab03..1834d11b1f 100644
--- a/browser/components/BrowserGlue.jsm
+++ b/browser/components/BrowserGlue.jsm
@@ -482,9 +482,6 @@ XPCOMUtils.defineLazyModuleGetters(this, {
   RemotePrompt: "resource:///modules/RemotePrompt.jsm",
 });
 
-/* global ContentPrefServiceParent:false, ContentSearch:false,
-          UpdateListener:false, webrtcUI:false */
-
 /**
  * IF YOU ADD OR REMOVE FROM THIS LIST, PLEASE UPDATE THE LIST ABOVE AS WELL.
  * XXX Bug 1325373 is for making eslint detect these automatically.
diff --git a/browser/components/downloads/DownloadsViewUI.jsm b/browser/components/downloads/DownloadsViewUI.jsm
index 24da156a4d..10d7f2fb28 100644
--- a/browser/components/downloads/DownloadsViewUI.jsm
+++ b/browser/components/downloads/DownloadsViewUI.jsm
@@ -327,8 +327,14 @@ this.DownloadsViewUI.DownloadElementShell.prototype = {
    *        Downloads View.
    */
   showStatusWithDetails(stateLabel, hoverStatus) {
+    let referrer =
+      this.download.source.referrerInfo &&
+      this.download.source.referrerInfo.originalReferrer
+        ? this.download.source.referrerInfo.originalReferrer.spec
+        : null;
+
     let [displayHost] = DownloadUtils.getURIHost(
-      this.download.source.referrer || this.download.source.url
+      referrer || this.download.source.url
     );
     let [displayDate] = DownloadUtils.getReadableDates(
       new Date(this.download.endTime)
diff --git a/browser/components/downloads/test/browser/browser.ini b/browser/components/downloads/test/browser/browser.ini
index 13a1ff88cd..98497a2943 100644
--- a/browser/components/downloads/test/browser/browser.ini
+++ b/browser/components/downloads/test/browser/browser.ini
@@ -16,3 +16,4 @@ skip-if = (os == 'win' && os_version == '10.0' && ccov) # Bug 1306510
 skip-if = true # Bug 1352792
 [browser_downloads_panel_height.js]
 [browser_downloads_autohide.js]
+[browser_go_to_download_page.js]
diff --git a/browser/components/downloads/test/browser/browser_go_to_download_page.js b/browser/components/downloads/test/browser/browser_go_to_download_page.js
new file mode 100644
index 0000000000..6a42a885a0
--- /dev/null
+++ b/browser/components/downloads/test/browser/browser_go_to_download_page.js
@@ -0,0 +1,93 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+const ReferrerInfo = Components.Constructor(
+  "@mozilla.org/referrer-info;1",
+  "nsIReferrerInfo",
+  "init"
+);
+
+const TEST_REFERRER = "https://example.com/";
+
+registerCleanupFunction(async function() {
+  await task_resetState();
+  await PlacesUtils.history.clear();
+});
+
+async function addDownload(referrerInfo) {
+  let startTimeMs = Date.now();
+
+  let publicList = await Downloads.getList(Downloads.PUBLIC);
+  let downloadData = {
+    source: {
+      url: "http://www.example.com/test-download.txt",
+      referrerInfo,
+    },
+    target: {
+      path: gTestTargetFile.path,
+    },
+    startTime: new Date(startTimeMs++),
+  };
+  let download = await Downloads.createDownload(downloadData);
+  await publicList.add(download);
+  await download.start();
+}
+
+/**
+ * Make sure "Go To Download Page" is enabled and works as expected.
+ */
+add_task(async function test_go_to_download_page() {
+  let referrerInfo = new ReferrerInfo(
+    Ci.nsIReferrerInfo.NO_REFERRER,
+    true,
+    NetUtil.newURI(TEST_REFERRER)
+  );
+
+  let tabPromise = BrowserTestUtils.waitForNewTab(gBrowser, TEST_REFERRER);
+
+  // Wait for focus first
+  await promiseFocus();
+
+  // Ensure that state is reset in case previous tests didn't finish.
+  await task_resetState();
+
+  // Populate the downloads database with the data required by this test.
+  await addDownload(referrerInfo);
+
+  // Open the user interface and wait for data to be fully loaded.
+  await task_openPanel();
+
+  let win = await openLibrary("Downloads");
+  registerCleanupFunction(function() {
+    win.close();
+  });
+
+  let listbox = win.document.getElementById("downloadsRichListBox");
+  ok(listbox, "download list box present");
+
+  // Select one of the downloads.
+  listbox.itemChildren[0].click();
+
+  let contextMenu = win.document.getElementById("downloadsContextMenu");
+
+  let popupShownPromise = BrowserTestUtils.waitForEvent(
+    contextMenu,
+    "popupshown"
+  );
+  EventUtils.synthesizeMouseAtCenter(
+    listbox.itemChildren[0],
+    { type: "contextmenu", button: 2 },
+    win
+  );
+  await popupShownPromise;
+
+  // Find and click "Go To Download Page"
+  let goToDownloadButton = [...contextMenu.children].find(
+    child => child.command == "downloadsCmd_openReferrer"
+  );
+  goToDownloadButton.click();
+
+  let newTab = await tabPromise;
+  ok(newTab, "Go To Download Page opened a new tab");
+  gBrowser.removeTab(newTab);
+});
diff --git a/browser/components/enterprisepolicies/content/aboutPolicies.js b/browser/components/enterprisepolicies/content/aboutPolicies.js
index 9ae8620447..87648c6f25 100644
--- a/browser/components/enterprisepolicies/content/aboutPolicies.js
+++ b/browser/components/enterprisepolicies/content/aboutPolicies.js
@@ -337,7 +337,7 @@ function generateDocumentation() {
 }
 
 let gInited = false;
-function init() {
+window.onload = function() {
   if (gInited) {
     return;
   }
@@ -371,7 +371,7 @@ function init() {
       sectionButton.click();
     }
   });
-}
+};
 
 function show(button) {
   let current_tab = document.querySelector(".active");
diff --git a/browser/components/enterprisepolicies/content/aboutPolicies.xhtml b/browser/components/enterprisepolicies/content/aboutPolicies.xhtml
index 4d69c44fce..ea3599d9b1 100644
--- a/browser/components/enterprisepolicies/content/aboutPolicies.xhtml
+++ b/browser/components/enterprisepolicies/content/aboutPolicies.xhtml
@@ -8,6 +8,7 @@
 
 <html xmlns="http://www.w3.org/1999/xhtml">
     <head>
+        <meta http-equiv="Content-Security-Policy" content="default-src chrome:" />
         <title data-l10n-id="about-policies-title"/>
         <link rel="stylesheet" href="chrome://browser/content/policies/aboutPolicies.css" type="text/css" />
         <link rel="localization" href="branding/brand.ftl"/>
@@ -16,7 +17,7 @@
         <link rel="localization" href="browser/policies/policies-descriptions.ftl"/>
         <script src="chrome://browser/content/policies/aboutPolicies.js" />
     </head>
-    <body id="body" onload="init()">
+    <body id="body">
         <div id="categories">
             <div class="category" selected="true" id="category-active">
                 <img class="category-icon" src="chrome://browser/content/policies/policies-active.svg"></img>
diff --git a/browser/components/extensions/parent/ext-browsingData.js b/browser/components/extensions/parent/ext-browsingData.js
index 4018ed55fa..439b6eee85 100644
--- a/browser/components/extensions/parent/ext-browsingData.js
+++ b/browser/components/extensions/parent/ext-browsingData.js
@@ -166,7 +166,7 @@ const clearLocalStorage = async function(options) {
     Services.obs.notifyObservers(null, "extension:purge-localStorage");
   }
 
-  if (Services.lsm.nextGenLocalStorageEnabled) {
+  if (Services.domStorageManager.nextGenLocalStorageEnabled) {
     // Ideally we could reuse the logic in Sanitizer.jsm or nsIClearDataService,
     // but this API exposes an ability to wipe data at a much finger granularity
     // than those APIs.  So custom logic is used here to wipe only the QM
diff --git a/browser/components/extensions/test/browser/browser_ext_addon_debugging_netmonitor.js b/browser/components/extensions/test/browser/browser_ext_addon_debugging_netmonitor.js
index 9d4d889d30..2c8459987b 100644
--- a/browser/components/extensions/test/browser/browser_ext_addon_debugging_netmonitor.js
+++ b/browser/components/extensions/test/browser/browser_ext_addon_debugging_netmonitor.js
@@ -3,7 +3,7 @@
 const { require } = ChromeUtils.import("resource://devtools/shared/Loader.jsm");
 
 const { DebuggerClient } = require("devtools/shared/client/debugger-client");
-const { DebuggerServer } = require("devtools/server/main");
+const { DebuggerServer } = require("devtools/server/debugger-server");
 const { gDevTools } = require("devtools/client/framework/devtools");
 const { Toolbox } = require("devtools/client/framework/toolbox");
 
@@ -28,9 +28,7 @@ async function setupToolboxTest(extensionId) {
     }
   }
 
-  const console = await toolbox.selectTool("webconsole");
-  const { hud } = console;
-  const { jsterm } = hud;
+  const consoleFront = await toolbox.target.getFront("console");
 
   const netmonitor = await toolbox.selectTool("netmonitor");
 
@@ -38,7 +36,7 @@ async function setupToolboxTest(extensionId) {
 
   // Call a function defined in the target extension to make it
   // fetch from an expected http url.
-  await jsterm.execute(`doFetchHTTPRequest("${expectedURL}");`);
+  await consoleFront.evaluateJSAsync(`doFetchHTTPRequest("${expectedURL}");`);
 
   await waitFor(() => {
     return !netmonitor.panelWin.document.querySelector(
@@ -68,7 +66,7 @@ async function setupToolboxTest(extensionId) {
 
   // Call a function defined in the target extension to make assertions
   // on the network requests collected by the netmonitor panel.
-  await jsterm.execute(
+  await consoleFront.evaluateJSAsync(
     `testNetworkRequestReceived(${JSON.stringify(requests)});`
   );
 
diff --git a/browser/components/extensions/test/browser/browser_ext_contextMenus.js b/browser/components/extensions/test/browser/browser_ext_contextMenus.js
index 25e62e1ef9..c1b40e37d7 100644
--- a/browser/components/extensions/test/browser/browser_ext_contextMenus.js
+++ b/browser/components/extensions/test/browser/browser_ext_contextMenus.js
@@ -4,8 +4,7 @@ Services.scriptloader.loadSubScript(
   "chrome://mochitests/content/browser/browser/components/places/tests/browser/head.js",
   this
 );
-/* globals withSidebarTree, synthesizeClickOnSelectedTreeCell,
- * promiseLibrary, promiseLibraryClosed
+/* globals withSidebarTree, synthesizeClickOnSelectedTreeCell, promiseLibrary, promiseLibraryClosed
  */
 
 const PAGE =
diff --git a/browser/components/extensions/test/browser/browser_ext_pageAction_popup_resize.js b/browser/components/extensions/test/browser/browser_ext_pageAction_popup_resize.js
index 1178bc0d0e..06a4623083 100644
--- a/browser/components/extensions/test/browser/browser_ext_pageAction_popup_resize.js
+++ b/browser/components/extensions/test/browser/browser_ext_pageAction_popup_resize.js
@@ -11,7 +11,6 @@ add_task(async function testPageActionPopupResize() {
       },
     },
     background: function() {
-      /* global browser */
       browser.tabs.query({ active: true, currentWindow: true }, tabs => {
         const tabId = tabs[0].id;
 
diff --git a/browser/components/extensions/test/browser/browser_ext_tabs_discard.js b/browser/components/extensions/test/browser/browser_ext_tabs_discard.js
index 7bcf2e6fe3..4f4f6d15c4 100644
--- a/browser/components/extensions/test/browser/browser_ext_tabs_discard.js
+++ b/browser/components/extensions/test/browser/browser_ext_tabs_discard.js
@@ -1,4 +1,4 @@
-/* global gBrowser SessionStore */
+/* global gBrowser */
 "use strict";
 
 add_task(async function test_discarded() {
diff --git a/browser/components/extensions/test/browser/browser_ext_tabs_highlight.js b/browser/components/extensions/test/browser/browser_ext_tabs_highlight.js
index 298a006480..d40c6833c1 100644
--- a/browser/components/extensions/test/browser/browser_ext_tabs_highlight.js
+++ b/browser/components/extensions/test/browser/browser_ext_tabs_highlight.js
@@ -1,4 +1,4 @@
-/* global gBrowser SessionStore */
+/* global gBrowser */
 "use strict";
 
 add_task(async function test_highlighted() {
diff --git a/browser/components/newtab/.eslintignore b/browser/components/newtab/.eslintignore
index f7f27c26af..1620218633 100644
--- a/browser/components/newtab/.eslintignore
+++ b/browser/components/newtab/.eslintignore
@@ -1,4 +1,3 @@
 data/
 logs/
-prerendered/
 vendor/
diff --git a/browser/components/newtab/.eslintrc.js b/browser/components/newtab/.eslintrc.js
index dbaea8769a..0d6baa5f3a 100644
--- a/browser/components/newtab/.eslintrc.js
+++ b/browser/components/newtab/.eslintrc.js
@@ -19,7 +19,7 @@ module.exports = {
 
     // Temporarily disabled since they aren't vendored into in mozilla central yet
     // "react-hooks", // require("react-hooks")
-    // "fetch-options", // require("eslint-plugin-fetch-options")
+    "fetch-options", // require("eslint-plugin-fetch-options")
   ],
   "settings": {
     "react": {
@@ -76,7 +76,7 @@ module.exports = {
   "rules": {
     // "react-hooks/rules-of-hooks": 2,
 
-    // "fetch-options/no-fetch-credentials": 2,
+    "fetch-options/no-fetch-credentials": 2,
 
     "react/jsx-boolean-value": [2, "always"],
     "react/jsx-closing-bracket-location": [2, "after-props"],
diff --git a/browser/components/newtab/AboutNewTabService.jsm b/browser/components/newtab/AboutNewTabService.jsm
index 29d7822ec0..682dd596fd 100644
--- a/browser/components/newtab/AboutNewTabService.jsm
+++ b/browser/components/newtab/AboutNewTabService.jsm
@@ -14,13 +14,8 @@ ChromeUtils.defineModuleGetter(this, "AboutNewTab",
                                "resource:///modules/AboutNewTab.jsm");
 
 const TOPIC_APP_QUIT = "quit-application-granted";
-const TOPIC_LOCALES_CHANGE = "intl:app-locales-changed";
 const TOPIC_CONTENT_DOCUMENT_INTERACTIVE = "content-document-interactive";
 
-// Automated tests ensure packaged locales are in this list. Copied output of:
-// https://github.com/mozilla/activity-stream/blob/master/bin/render-activity-stream-html.js
-const ACTIVITY_STREAM_BCP47 = "en-US".split(" ");
-
 const ABOUT_URL = "about:newtab";
 const BASE_URL = "resource://activity-stream/";
 const ACTIVITY_STREAM_PAGES = new Set(["home", "newtab", "welcome"]);
@@ -35,7 +30,6 @@ const PREF_ACTIVITY_STREAM_DEBUG = "browser.newtabpage.activity-stream.debug";
 
 function AboutNewTabService() {
   Services.obs.addObserver(this, TOPIC_APP_QUIT);
-  Services.obs.addObserver(this, TOPIC_LOCALES_CHANGE);
   Services.prefs.addObserver(PREF_SEPARATE_PRIVILEGED_CONTENT_PROCESS, this);
   if (!IS_RELEASE_OR_BETA) {
     Services.prefs.addObserver(PREF_ACTIVITY_STREAM_DEBUG, this);
@@ -71,7 +65,7 @@ function AboutNewTabService() {
  *
  * When the URL loaded is about:newtab, the default behavior, or when entered in the
  * URL bar, the redirector is hit. The service is then called to return the
- * appropriate activity stream url based on prefs and locales.
+ * appropriate activity stream url based on prefs.
  *
  * NOTE: "about:newtab" will always result in a default newtab page, and never an overridden URL.
  *
@@ -88,7 +82,6 @@ AboutNewTabService.prototype = {
 
   _newTabURL: ABOUT_URL,
   _activityStreamEnabled: false,
-  _activityStreamPath: "",
   _activityStreamDebug: false,
   _privilegedContentProcess: false,
   _overridden: false,
@@ -105,11 +98,9 @@ AboutNewTabService.prototype = {
       case "nsPref:changed":
         if (data === PREF_SEPARATE_PRIVILEGED_CONTENT_PROCESS) {
           this._privilegedContentProcess = Services.prefs.getBoolPref(PREF_SEPARATE_PRIVILEGED_CONTENT_PROCESS);
-          this.updatePrerenderedPath();
           this.notifyChange();
         } else if (!IS_RELEASE_OR_BETA && data === PREF_ACTIVITY_STREAM_DEBUG) {
           this._activityStreamDebug = Services.prefs.getBoolPref(PREF_ACTIVITY_STREAM_DEBUG, false);
-          this.updatePrerenderedPath();
           this.notifyChange();
         }
         break;
@@ -145,10 +136,8 @@ AboutNewTabService.prototype = {
             `${BASE_URL}vendor/react${debugString}.js`,
             `${BASE_URL}vendor/react-dom${debugString}.js`,
             `${BASE_URL}vendor/prop-types.js`,
-            `${BASE_URL}vendor/react-intl.js`,
             `${BASE_URL}vendor/redux.js`,
             `${BASE_URL}vendor/react-redux.js`,
-            `${BASE_URL}prerendered/${this.activityStreamLocale}/activity-stream-strings.js`,
             `${BASE_URL}data/content/activity-stream.bundle.js`,
           ];
 
@@ -175,10 +164,6 @@ AboutNewTabService.prototype = {
           Services.obs.removeObserver(this, TOPIC_CONTENT_DOCUMENT_INTERACTIVE);
         }
         break;
-      case TOPIC_LOCALES_CHANGE:
-        this.updatePrerenderedPath();
-        this.notifyChange();
-        break;
     }
   },
 
@@ -210,34 +195,23 @@ AboutNewTabService.prototype = {
     if (!IS_RELEASE_OR_BETA) {
       this._activityStreamDebug = Services.prefs.getBoolPref(PREF_ACTIVITY_STREAM_DEBUG, false);
     }
-    this.updatePrerenderedPath();
     this._newtabURL = ABOUT_URL;
     return true;
   },
 
-  /**
-   * Figure out what path under prerendered to use based on current state.
-   */
-  updatePrerenderedPath() {
-    // Debug files are specially packaged in a non-localized directory, but with
-    // dynamic script loading, localized debug is supported.
-    this._activityStreamPath = `${this._activityStreamDebug &&
-      !this._privilegedContentProcess ? "static" : this.activityStreamLocale}/`;
-  },
-
   /*
    * Returns the default URL.
    *
-   * This URL depends on various activity stream prefs and locales. Overriding
+   * This URL depends on various activity stream prefs. Overriding
    * the newtab page has no effect on the result of this function.
    */
   get defaultURL() {
     // Generate the desired activity stream resource depending on state, e.g.,
-    // resource://activity-stream/prerendered/ar/activity-stream.html
-    // resource://activity-stream/prerendered/static/activity-stream-debug.html
+    // "resource://activity-stream/prerendered/activity-stream.html"
+    // "resource://activity-stream/prerendered/activity-stream-debug.html"
+    // "resource://activity-stream/prerendered/activity-stream-noscripts.html"
     return [
       "resource://activity-stream/prerendered/",
-      this._activityStreamPath,
       "activity-stream",
       // Debug version loads dev scripts but noscripts separately loads scripts
       this._activityStreamDebug && !this._privilegedContentProcess ? "-debug" : "",
@@ -287,21 +261,6 @@ AboutNewTabService.prototype = {
     return this._activityStreamDebug;
   },
 
-  get activityStreamLocale() {
-    // Pick the best available locale to match the app locales
-    return Services.locale.negotiateLanguages(
-      // Fix up incorrect BCP47 that are actually lang tags as a workaround for
-      // bug 1479606 returning the wrong values in the content process
-      Services.locale.appLocalesAsBCP47.map(l => l.replace(/^(ja-JP-mac)$/, "$1os")),
-      ACTIVITY_STREAM_BCP47,
-      // defaultLocale's strings aren't necessarily packaged, but en-US' are
-      "en-US",
-      Services.locale.langNegStrategyLookup
-    // Convert the BCP47 to lang tag, which is what is used in our paths, as a
-    // workaround for bug 1478930 negotiating incorrectly with lang tags
-    )[0].replace(/^(ja-JP-mac)os$/, "$1");
-  },
-
   resetNewTabURL() {
     this._overridden = false;
     this._newTabURL = ABOUT_URL;
@@ -328,7 +287,6 @@ AboutNewTabService.prototype = {
       return;
     }
     Services.obs.removeObserver(this, TOPIC_APP_QUIT);
-    Services.obs.removeObserver(this, TOPIC_LOCALES_CHANGE);
     Services.prefs.removeObserver(PREF_SEPARATE_PRIVILEGED_CONTENT_PROCESS, this);
     if (!IS_RELEASE_OR_BETA) {
       Services.prefs.removeObserver(PREF_ACTIVITY_STREAM_DEBUG, this);
diff --git a/browser/components/newtab/bin/render-activity-stream-html.js b/browser/components/newtab/bin/render-activity-stream-html.js
index f67d62ea59..b96c67176d 100644
--- a/browser/components/newtab/bin/render-activity-stream-html.js
+++ b/browser/components/newtab/bin/render-activity-stream-html.js
@@ -3,8 +3,6 @@ const fs = require("fs");
 const {mkdir} = require("shelljs");
 const path = require("path");
 
-const {CENTRAL_LOCALES, DEFAULT_LOCALE} = require("./locales");
-
 // Note: DEFAULT_OPTIONS.baseUrl should match BASE_URL in aboutNewTabService.js
 //       in mozilla-central.
 const DEFAULT_OPTIONS = {
@@ -12,52 +10,11 @@ const DEFAULT_OPTIONS = {
   baseUrl: "resource://activity-stream/",
 };
 
-// Locales that should be displayed RTL
-const RTL_LIST = ["ar", "he", "fa", "ur"];
-
-/**
- * Get the language part of the locale.
- */
-function getLanguage(locale) {
-  return locale.split("-")[0];
-}
-
-/**
- * Get the best strings for a single provided locale using similar locales and
- * DEFAULT_LOCALE as fallbacks.
- */
-function getStrings(locale, allStrings) {
-  const availableLocales = Object.keys(allStrings);
-
-  const language = getLanguage(locale);
-  const similarLocales = availableLocales.filter(other =>
-    other !== locale && getLanguage(other) === language);
-
-  // Rank locales from least desired to most desired
-  const localeFallbacks = [DEFAULT_LOCALE, ...similarLocales, locale];
-
-  // Get strings from each locale replacing with those from more desired ones
-  const desired = Object.assign({}, ...localeFallbacks.map(l => allStrings[l]));
-
-  // Only include strings that are currently used (defined by default locale)
-  return Object.assign({}, ...Object.keys(allStrings[DEFAULT_LOCALE]).map(
-    key => ({[key]: desired[key]})));
-}
-
-/**
- * Get the text direction of the locale.
- */
-function getTextDirection(locale) {
-  return RTL_LIST.includes(locale.split("-")[0]) ? "rtl" : "ltr";
-}
-
 /**
  * templateHTML - Generates HTML for activity stream, given some options and
  * prerendered HTML if necessary.
  *
  * @param  {obj} options
- *         {str} options.locale         The locale to render in lang="" attribute
- *         {str} options.direction      The language direction to render in dir="" attribute
  *         {str} options.baseUrl        The base URL for all local assets
  *         {bool} options.debug         Should we use dev versions of JS libraries?
  *         {bool} options.noscripts     Should we include scripts in the prerendered files?
@@ -71,10 +28,8 @@ function templateHTML(options) {
     `${options.baseUrl}vendor/react${debugString}.js`,
     `${options.baseUrl}vendor/react-dom${debugString}.js`,
     `${options.baseUrl}vendor/prop-types.js`,
-    `${options.baseUrl}vendor/react-intl.js`,
     `${options.baseUrl}vendor/redux.js`,
     `${options.baseUrl}vendor/react-redux.js`,
-    `${options.baseUrl}prerendered/${options.locale}/activity-stream-strings.js`,
     `${options.baseUrl}data/content/activity-stream.bundle.js`,
   ];
 
@@ -82,7 +37,7 @@ function templateHTML(options) {
   const scriptRender = `\n${scripts.map(script => `    <script src="${script}"></script>`).join("\n")}`;
 
   return `<!doctype html>
-<html lang="${options.locale}" dir="${options.direction}">
+<html>
   <head>
     <meta charset="utf-8">
     <meta http-equiv="Content-Security-Policy" content="default-src 'none'; object-src 'none'; script-src resource: chrome:; connect-src https:; img-src https: data: blob:; style-src 'unsafe-inline';">
@@ -102,49 +57,24 @@ function templateHTML(options) {
 `;
 }
 
-/**
- * templateJs - Generates a js file that passes the initial state of the prerendered
- * DOM to the React version. This is necessary to ensure the checksum matches when
- * React mounts so that it can attach to the prerendered elements instead of blowing
- * them away.
- *
- * Note that this may no longer be necessary in React 16 and we should review whether
- * it is still necessary.
- *
- * @param  {string} name The name of the global to expose
- * @param  {string} desc Extra description to include in a js comment
- * @param  {obj}   state The data to expose as a window global
- * @return {str}         The js file as a string
- */
-function templateJs(name, desc, state) {
-  return `// Note - this is a generated ${desc} file.
-window.${name} = ${JSON.stringify(state, null, 2)};
-`;
-}
-
 /**
  * writeFiles - Writes to the desired files the result of a template given
  * various prerendered data and options.
  *
- * @param {string} name          Something to identify in the console
  * @param {string} destPath      Path to write the files to
  * @param {Map}    filesMap      Mapping of a string file name to templater
  * @param {Object} options       Various options for the templater
  */
-function writeFiles(name, destPath, filesMap, options) {
+function writeFiles(destPath, filesMap, options) {
   for (const [file, templater] of filesMap) {
+    console.log("\x1b[32m", `✓ ${file}`, "\x1b[0m");
     fs.writeFileSync(path.join(destPath, file), templater({options}));
   }
-  console.log("\x1b[32m", `✓ ${name}`, "\x1b[0m");
 }
 
 const STATIC_FILES = new Map([
-  ["activity-stream-debug.html", ({options}) => templateHTML(options)],
-]);
-
-const LOCALIZED_FILES = new Map([
-  ["activity-stream-strings.js", ({options: {locale, strings}}) => templateJs("gActivityStreamStrings", locale, strings)],
   ["activity-stream.html", ({options}) => templateHTML(options)],
+  ["activity-stream-debug.html", ({options}) => templateHTML(Object.assign({}, options, {debug: true}))],
   ["activity-stream-noscripts.html", ({options}) => templateHTML(Object.assign({}, options, {noscripts: true}))],
 ]);
 
@@ -163,74 +93,13 @@ function main() { // eslint-disable-line max-statements
     },
   });
 
-  const baseOptions = Object.assign({debug: false}, DEFAULT_OPTIONS, args || {});
-  const addonPath = path.resolve(__dirname, baseOptions.addonPath);
-  const allStrings = require(`${baseOptions.addonPath}/data/locales.json`);
-  const extraLocales = Object.keys(allStrings).filter(locale =>
-    locale !== DEFAULT_LOCALE && !CENTRAL_LOCALES.includes(locale));
-
+  const options = Object.assign({debug: false}, DEFAULT_OPTIONS, args || {});
+  const addonPath = path.resolve(__dirname, options.addonPath);
   const prerenderedPath = path.join(addonPath, "prerendered");
-  console.log(`Writing prerendered files to individual directories under ${prerenderedPath}:`);
+  console.log(`Writing prerendered files to ${prerenderedPath}:`);
 
-  // Save default locale's strings to compare against other locales' strings
-  let defaultStrings;
-  let langStrings;
-  const isSubset = (strings, existing) => existing &&
-    Object.keys(strings).every(key => strings[key] === existing[key]);
-
-  // Process the default locale first then all the ones from mozilla-central
-  const localizedLocales = [];
-  const skippedLocales = [];
-  for (const locale of [DEFAULT_LOCALE, ...CENTRAL_LOCALES]) {
-    // Skip the locale if it would have resulted in duplicate packaged files
-    const strings = getStrings(locale, allStrings);
-    if (isSubset(strings, defaultStrings) || isSubset(strings, langStrings)) {
-      skippedLocales.push(locale);
-      continue;
-    }
-
-    const options = Object.assign({}, baseOptions, {
-      direction: getTextDirection(locale),
-      locale,
-      strings,
-    });
-
-    // Put locale-specific files in their own directory
-    const localePath = path.join(prerenderedPath, "locales", locale);
-    mkdir("-p", localePath);
-    writeFiles(locale, localePath, LOCALIZED_FILES, options);
-
-    // Only write static files once for the default locale
-    if (locale === DEFAULT_LOCALE) {
-      const staticPath = path.join(prerenderedPath, "static");
-      mkdir("-p", staticPath);
-      writeFiles(`${locale} (static)`, staticPath, STATIC_FILES,
-        Object.assign({}, options, {debug: true}));
-
-      // Save the default strings to compare against other locales' strings
-      defaultStrings = strings;
-    }
-
-    // Save the language's strings to maybe reuse for the next similar locales
-    if (getLanguage(locale) === locale) {
-      langStrings = strings;
-    }
-
-    localizedLocales.push(locale);
-  }
-
-  if (skippedLocales.length) {
-    console.log("\x1b[33m", `Skipped the following locales because they use the same strings as ${DEFAULT_LOCALE} or its language locale: ${skippedLocales.join(", ")}`, "\x1b[0m");
-  }
-  if (extraLocales.length) {
-    console.log("\x1b[33m", `Skipped the following locales because they are not in CENTRAL_LOCALES: ${extraLocales.join(", ")}`, "\x1b[0m");
-  }
-
-  // Convert ja-JP-mac lang tag to ja-JP-macos bcp47 to work around bug 1478930
-  const bcp47String = localizedLocales.join(" ").replace(/(ja-JP-mac)/, "$1os");
-
-  // Provide some help to copy/paste locales if tests are failing
-  console.log(`\nIf aboutNewTabService tests are failing for unexpected locales, make sure its list is updated:\nconst ACTIVITY_STREAM_BCP47 = "${bcp47String}".split(" ");`);
+  mkdir("-p", prerenderedPath);
+  writeFiles(prerenderedPath, STATIC_FILES, options);
 }
 
 main();
diff --git a/browser/components/newtab/bin/vendor.js b/browser/components/newtab/bin/vendor.js
index 4f6b543ce8..5bb994de20 100644
--- a/browser/components/newtab/bin/vendor.js
+++ b/browser/components/newtab/bin/vendor.js
@@ -13,8 +13,6 @@ const filesToVendor = {
   "react/umd/react.development.js": "react-dev.js",
   "react-dom/umd/react-dom.production.min.js": "react-dom.js",
   "react-dom/umd/react-dom.development.js": "react-dom-dev.js",
-  "react-intl/LICENSE.md": "REACT_INTL_LICENSE",
-  "react-intl/dist/react-intl.min.js": "react-intl.js",
   "react-redux/LICENSE.md": "REACT_REDUX_LICENSE",
   "react-redux/dist/react-redux.min.js": "react-redux.js",
 };
diff --git a/browser/components/newtab/jar.mn b/browser/components/newtab/jar.mn
index e93f7d3604..edc64f186a 100644
--- a/browser/components/newtab/jar.mn
+++ b/browser/components/newtab/jar.mn
@@ -14,7 +14,6 @@ browser.jar:
   res/activity-stream/vendor/react-dom-dev.js (./vendor/react-dom-dev.js)
 #endif
   res/activity-stream/vendor/prop-types.js (./vendor/prop-types.js)
-  res/activity-stream/vendor/react-intl.js (./vendor/react-intl.js)
   res/activity-stream/vendor/redux.js (./vendor/redux.js)
   res/activity-stream/vendor/react-redux.js (./vendor/react-redux.js)
   res/activity-stream/data/content/assets/ (./data/content/assets/*)
@@ -27,7 +26,8 @@ browser.jar:
 #else
   res/activity-stream/css/activity-stream.css (./css/activity-stream-linux.css)
 #endif
+  res/activity-stream/prerendered/activity-stream.html (./prerendered/activity-stream.html)
 #ifndef RELEASE_OR_BETA
-  res/activity-stream/prerendered/static/activity-stream-debug.html (./prerendered/static/activity-stream-debug.html)
+  res/activity-stream/prerendered/activity-stream-debug.html (./prerendered/activity-stream-debug.html)
 #endif
-  res/activity-stream/prerendered/ (./prerendered/locales/*)
+  res/activity-stream/prerendered/activity-stream-noscripts.html (./prerendered/activity-stream-noscripts.html)
diff --git a/browser/components/newtab/lib/ActivityStreamMessageChannel.jsm b/browser/components/newtab/lib/ActivityStreamMessageChannel.jsm
index b21d5e1c3e..53aca154d9 100644
--- a/browser/components/newtab/lib/ActivityStreamMessageChannel.jsm
+++ b/browser/components/newtab/lib/ActivityStreamMessageChannel.jsm
@@ -6,8 +6,8 @@
 
 const { AboutNewTab } = ChromeUtils.import(
   "resource:///modules/AboutNewTab.jsm"
-); // Remove when updating eslint-plugin-mozilla 0.14.0+
-/* globals RemotePages */ const { RemotePages } = ChromeUtils.import(
+);
+const { RemotePages } = ChromeUtils.import(
   "resource://gre/modules/remotepagemanager/RemotePageManagerParent.jsm"
 );
 
diff --git a/browser/components/newtab/nsIAboutNewTabService.idl b/browser/components/newtab/nsIAboutNewTabService.idl
index a157bfdf82..e8b0593711 100644
--- a/browser/components/newtab/nsIAboutNewTabService.idl
+++ b/browser/components/newtab/nsIAboutNewTabService.idl
@@ -49,11 +49,6 @@ interface nsIAboutNewTabService : nsISupports
    */
   readonly attribute bool activityStreamDebug;
 
-  /**
-   * Returns the locale of the activity stream interface
-   */
-  readonly attribute ACString activityStreamLocale;
-
   /**
    * Resets to the default resource and also resets the
    * overridden attribute to false.
diff --git a/browser/components/newtab/package-lock.json b/browser/components/newtab/package-lock.json
index fac2f6a6f1..45816d73f9 100644
--- a/browser/components/newtab/package-lock.json
+++ b/browser/components/newtab/package-lock.json
@@ -5361,32 +5361,6 @@
       "integrity": "sha512-mT34yGKMNceBQUoVn7iCDKDntA7SC6gycMAWzGx1z/CMCTV7b2AAtXlo3nRyHZ1FelRkQbQjprHSYGwzLtkVbw==",
       "dev": true
     },
-    "intl-format-cache": {
-      "version": "2.2.2",
-      "resolved": "https://registry.npmjs.org/intl-format-cache/-/intl-format-cache-2.2.2.tgz",
-      "integrity": "sha512-B5XmTTcF7Yz5VACwVLmAUkqK27RnOCvgi0kwA6Al/vzVPHy+h+G8J7SCyzZDMjb/UB8fqBEyrzecyn1ksRIi9A=="
-    },
-    "intl-messageformat": {
-      "version": "2.2.0",
-      "resolved": "https://registry.npmjs.org/intl-messageformat/-/intl-messageformat-2.2.0.tgz",
-      "integrity": "sha1-NFvNRt5jC3aDMwwuUhd/9eq0hPw=",
-      "requires": {
-        "intl-messageformat-parser": "1.4.0"
-      }
-    },
-    "intl-messageformat-parser": {
-      "version": "1.4.0",
-      "resolved": "https://registry.npmjs.org/intl-messageformat-parser/-/intl-messageformat-parser-1.4.0.tgz",
-      "integrity": "sha1-tD1FqXRoytvkQzHXS7Ho3qRPwHU="
-    },
-    "intl-relativeformat": {
-      "version": "2.1.1",
-      "resolved": "https://registry.npmjs.org/intl-relativeformat/-/intl-relativeformat-2.1.1.tgz",
-      "integrity": "sha512-bAhhgiCiN+MVjQeK2v9YqCRJQ8FfV0tk9WVh1RYkRJerpYhmpBe2I4XxpneY232Cp9ujHVl3Q465UJkHQEQdmQ==",
-      "requires": {
-        "intl-messageformat": "^2.0.0"
-      }
-    },
     "invariant": {
       "version": "2.2.4",
       "resolved": "https://registry.npmjs.org/invariant/-/invariant-2.2.4.tgz",
@@ -8718,18 +8692,6 @@
         }
       }
     },
-    "react-intl": {
-      "version": "2.9.0",
-      "resolved": "https://registry.npmjs.org/react-intl/-/react-intl-2.9.0.tgz",
-      "integrity": "sha512-27jnDlb/d2A7mSJwrbOBnUgD+rPep+abmoJE511Tf8BnoONIAUehy/U1zZCHGO17mnOwMWxqN4qC0nW11cD6rA==",
-      "requires": {
-        "hoist-non-react-statics": "^3.3.0",
-        "intl-format-cache": "^2.0.5",
-        "intl-messageformat": "^2.1.0",
-        "intl-relativeformat": "^2.1.0",
-        "invariant": "^2.1.1"
-      }
-    },
     "react-is": {
       "version": "16.8.4",
       "resolved": "https://registry.npmjs.org/react-is/-/react-is-16.8.4.tgz",
diff --git a/browser/components/newtab/package.json b/browser/components/newtab/package.json
index 04acdd6a64..71eb915bc2 100644
--- a/browser/components/newtab/package.json
+++ b/browser/components/newtab/package.json
@@ -11,7 +11,6 @@
     "fluent-react": "0.8.4",
     "react": "16.8.6",
     "react-dom": "16.8.6",
-    "react-intl": "2.9.0",
     "react-redux": "7.0.3",
     "redux": "4.0.1",
     "reselect": "4.0.0"
diff --git a/browser/components/newtab/prerendered/static/activity-stream-debug.html b/browser/components/newtab/prerendered/activity-stream-debug.html
similarity index 88%
rename from browser/components/newtab/prerendered/static/activity-stream-debug.html
rename to browser/components/newtab/prerendered/activity-stream-debug.html
index f313e1d78f..961f06cadf 100644
--- a/browser/components/newtab/prerendered/static/activity-stream-debug.html
+++ b/browser/components/newtab/prerendered/activity-stream-debug.html
@@ -1,5 +1,5 @@
 <!doctype html>
-<html lang="en-US" dir="ltr">
+<html>
   <head>
     <meta charset="utf-8">
     <meta http-equiv="Content-Security-Policy" content="default-src 'none'; object-src 'none'; script-src resource: chrome:; connect-src https:; img-src https: data: blob:; style-src 'unsafe-inline';">
@@ -19,10 +19,8 @@
     <script src="resource://activity-stream/vendor/react-dev.js"></script>
     <script src="resource://activity-stream/vendor/react-dom-dev.js"></script>
     <script src="resource://activity-stream/vendor/prop-types.js"></script>
-    <script src="resource://activity-stream/vendor/react-intl.js"></script>
     <script src="resource://activity-stream/vendor/redux.js"></script>
     <script src="resource://activity-stream/vendor/react-redux.js"></script>
-    <script src="resource://activity-stream/prerendered/en-US/activity-stream-strings.js"></script>
     <script src="resource://activity-stream/data/content/activity-stream.bundle.js"></script>
   </body>
 </html>
diff --git a/browser/components/newtab/prerendered/locales/en-US/activity-stream-noscripts.html b/browser/components/newtab/prerendered/activity-stream-noscripts.html
similarity index 96%
rename from browser/components/newtab/prerendered/locales/en-US/activity-stream-noscripts.html
rename to browser/components/newtab/prerendered/activity-stream-noscripts.html
index aebe8bd066..bbe8f75807 100644
--- a/browser/components/newtab/prerendered/locales/en-US/activity-stream-noscripts.html
+++ b/browser/components/newtab/prerendered/activity-stream-noscripts.html
@@ -1,5 +1,5 @@
 <!doctype html>
-<html lang="en-US" dir="ltr">
+<html>
   <head>
     <meta charset="utf-8">
     <meta http-equiv="Content-Security-Policy" content="default-src 'none'; object-src 'none'; script-src resource: chrome:; connect-src https:; img-src https: data: blob:; style-src 'unsafe-inline';">
diff --git a/browser/components/newtab/prerendered/locales/en-US/activity-stream.html b/browser/components/newtab/prerendered/activity-stream.html
similarity index 88%
rename from browser/components/newtab/prerendered/locales/en-US/activity-stream.html
rename to browser/components/newtab/prerendered/activity-stream.html
index a6a5b2bc1f..2c248121ed 100644
--- a/browser/components/newtab/prerendered/locales/en-US/activity-stream.html
+++ b/browser/components/newtab/prerendered/activity-stream.html
@@ -1,5 +1,5 @@
 <!doctype html>
-<html lang="en-US" dir="ltr">
+<html>
   <head>
     <meta charset="utf-8">
     <meta http-equiv="Content-Security-Policy" content="default-src 'none'; object-src 'none'; script-src resource: chrome:; connect-src https:; img-src https: data: blob:; style-src 'unsafe-inline';">
@@ -19,10 +19,8 @@
     <script src="resource://activity-stream/vendor/react.js"></script>
     <script src="resource://activity-stream/vendor/react-dom.js"></script>
     <script src="resource://activity-stream/vendor/prop-types.js"></script>
-    <script src="resource://activity-stream/vendor/react-intl.js"></script>
     <script src="resource://activity-stream/vendor/redux.js"></script>
     <script src="resource://activity-stream/vendor/react-redux.js"></script>
-    <script src="resource://activity-stream/prerendered/en-US/activity-stream-strings.js"></script>
     <script src="resource://activity-stream/data/content/activity-stream.bundle.js"></script>
   </body>
 </html>
diff --git a/browser/components/newtab/prerendered/locales/en-US/activity-stream-strings.js b/browser/components/newtab/prerendered/locales/en-US/activity-stream-strings.js
deleted file mode 100644
index 67578c835f..0000000000
--- a/browser/components/newtab/prerendered/locales/en-US/activity-stream-strings.js
+++ /dev/null
@@ -1,2 +0,0 @@
-// Note - this is a generated en-US file.
-window.gActivityStreamStrings = {};
diff --git a/browser/components/newtab/vendor/REACT_INTL_LICENSE b/browser/components/newtab/vendor/REACT_INTL_LICENSE
deleted file mode 100644
index 0da75135fb..0000000000
--- a/browser/components/newtab/vendor/REACT_INTL_LICENSE
+++ /dev/null
@@ -1,27 +0,0 @@
-Copyright 2014 Yahoo Inc.
-All rights reserved.
-
-Redistribution and use in source and binary forms, with or without
-modification, are permitted provided that the following conditions are met:
-
-    * Redistributions of source code must retain the above copyright
-      notice, this list of conditions and the following disclaimer.
-
-    * Redistributions in binary form must reproduce the above copyright
-      notice, this list of conditions and the following disclaimer in the
-      documentation and/or other materials provided with the distribution.
-
-    * Neither the name of the Yahoo Inc. nor the
-      names of its contributors may be used to endorse or promote products
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-
-THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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diff --git a/browser/components/newtab/vendor/react-intl.js b/browser/components/newtab/vendor/react-intl.js
deleted file mode 100644
index 6b57fbcf30..0000000000
--- a/browser/components/newtab/vendor/react-intl.js
+++ /dev/null
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fit","lookup"]),_e=me(["narrow","short","long"]),be=me(["numeric","2-digit"]),we=pe.isRequired,Fe={locale:fe,timeZone:fe,formats:he,messages:he,textComponent:ye,defaultLocale:fe,defaultFormats:he,onError:pe},Oe={formatDate:we,formatTime:we,formatRelative:we,formatNumber:we,formatPlural:we,formatMessage:we,formatHTMLMessage:we},xe=de(oe({},Fe,Oe,{formatters:he,now:we})),Te=(fe.isRequired,ve([fe,he]),{localeMatcher:ge,formatMatcher:me(["basic","best fit"]),timeZone:fe,hour12:ue,weekday:_e,era:_e,year:be,month:me(["numeric","2-digit","narrow","short","long"]),day:be,hour:be,minute:be,second:be,timeZoneName:me(["short","long"])}),Pe={localeMatcher:ge,style:me(["decimal","currency","percent"]),currency:fe,currencyDisplay:me(["symbol","code","name"]),useGrouping:ue,minimumIntegerDigits:ce,minimumFractionDigits:ce,maximumFractionDigits:ce,minimumSignificantDigits:ce,maximumSignificantDigits:ce},je={style:me(["best fit","numeric"]),units:me(["second","minute","hour","day","month","year","second-short","minute-short","hour-short","day-short","month-short","year-short"])},Ne={style:me(["cardinal","ordinal"])},Ce={childContextTypes:!0,contextTypes:!0,defaultProps:!0,displayName:!0,getDefaultProps:!0,getDerivedStateFromProps:!0,mixins:!0,propTypes:!0,type:!0},ke={name:!0,length:!0,prototype:!0,caller:!0,callee:!0,arguments:!0,arity:!0},Ee=Object.defineProperty,Ae=Object.getOwnPropertyNames,Me=Object.getOwnPropertySymbols,Re=Object.getOwnPropertyDescriptor,De=Object.getPrototypeOf,Ie=De&&De(Object),Le=d,Se=function(e,t,r,n,o,a,i,s){if(!e){var l;if(void 0===t)l=new Error("Minified exception occurred; use the non-minified dev environment for the full error message and additional helpful warnings.");else{var u=[r,n,o,a,i,s],c=0;(l=new Error(t.replace(/%s/g,function(){return u[c++]}))).name="Invariant Violation"}throw l.framesToPop=1,l}},Ue=Object.keys(Fe),Ze={"&":"&amp;",">":"&gt;","<":"&lt;",'"':"&quot;","'":"&#x27;"},qe=/[&><"']/g,Ge=function e(t){var r=arguments.length>1&&void 0!==arguments[1]?arguments[1]:{};te(this,e);var n="ordinal"===r.style,o=T(x(t));this.format=function(e){return o(e,n)}},He=Function.prototype.bind||function(e){if("function"!=typeof this)throw new TypeError("Function.prototype.bind - what is trying to be bound is not callable");var t=Array.prototype.slice.call(arguments,1),r=this,n=function(){},o=function(){return r.apply(this instanceof n?this:e,t.concat(Array.prototype.slice.call(arguments)))};return this.prototype&&(n.prototype=this.prototype),o.prototype=new n,o},We=Object.prototype.hasOwnProperty,Ve=function(){try{return!!Object.defineProperty({},"a",{})}catch(e){return!1}}()?Object.defineProperty:function(e,t,r){"get"in r&&e.__defineGetter__?e.__defineGetter__(t,r.get):(!We.call(e,t)||"value"in r)&&(e[t]=r.value)},Be=Object.create||function(e,t){function r(){}var n,o;r.prototype=e,n=new r;for(o in t)We.call(t,o)&&Ve(n,o,t[o]);return n},Je=Object.keys(Te),$e=Object.keys(Pe),ze=Object.keys(je),Ke=Object.keys(Ne),Qe={second:60,minute:60,hour:24,day:30,month:12},Xe=Object.freeze({formatDate:function(e,t,r){var n=arguments.length>3&&void 0!==arguments[3]?arguments[3]:{},o=e.locale,a=e.formats,i=e.timeZone,s=n.format,l=e.onError||F,u=new Date(r),c=oe({},i&&{timeZone:i},s&&k(a,"date",s,l)),f=v(n,Je,c);try{return t.getDateTimeFormat(o,f).format(u)}catch(e){l(w("Error formatting date.",e))}return String(u)},formatTime:function(e,t,r){var n=arguments.length>3&&void 0!==arguments[3]?arguments[3]:{},o=e.locale,a=e.formats,i=e.timeZone,s=n.format,l=e.onError||F,u=new Date(r),c=oe({},i&&{timeZone:i},s&&k(a,"time",s,l)),f=v(n,Je,c);f.hour||f.minute||f.second||(f=oe({},f,{hour:"numeric",minute:"numeric"}));try{return t.getDateTimeFormat(o,f).format(u)}catch(e){l(w("Error formatting time.",e))}return String(u)},formatRelative:function(e,t,r){var n=arguments.length>3&&void 0!==arguments[3]?arguments[3]:{},o=e.locale,a=e.formats,i=n.format,s=e.onError||F,l=new Date(r),u=new Date(n.now),c=i&&k(a,"relative",i,s),p=v(n,ze,c),h=oe({},f.thresholds);C(Qe);try{return t.getRelativeFormat(o,p).format(l,{now:isFinite(u)?u:t.now()})}catch(e){s(w("Error formatting relative time.",e))}finally{C(h)}return String(l)},formatNumber:function(e,t,r){var n=arguments.length>3&&void 0!==arguments[3]?arguments[3]:{},o=e.locale,a=e.formats,i=n.format,s=e.onError||F,l=i&&k(a,"number",i,s),u=v(n,$e,l);try{return t.getNumberFormat(o,u).format(r)}catch(e){s(w("Error formatting number.",e))}return String(r)},formatPlural:function(e,t,r){var n=arguments.length>3&&void 0!==arguments[3]?arguments[3]:{},o=e.locale,a=v(n,Ke),i=e.onError||F;try{return t.getPluralFormat(o,a).format(r)}catch(e){i(w("Error formatting plural.",e))}return"other"},formatMessage:E,formatHTMLMessage:function(e,t,r){var n=arguments.length>3&&void 0!==arguments[3]?arguments[3]:{};return E(e,t,r,Object.keys(n).reduce(function(e,t){var r=n[t];return e[t]="string"==typeof r?y(r):r,e},{}))}}),Ye=Object.keys(Fe),et=Object.keys(Oe),tt={formats:{},messages:{},timeZone:null,textComponent:"span",defaultLocale:"en",defaultFormats:{},onError:F},rt=function(e){function t(e){var r=arguments.length>1&&void 0!==arguments[1]?arguments[1]:{};te(this,t);var n=se(this,(t.__proto__||Object.getPrototypeOf(t)).call(this,e,r));Se("undefined"!=typeof Intl,"[React Intl] The `Intl` APIs must be available in the runtime, and do not appear to be built-in. An `Intl` polyfill should be loaded.\nSee: http://formatjs.io/guides/runtime-environments/");var o=r.intl,a=void 0;a=isFinite(e.initialNow)?Number(e.initialNow):o?o.now():Date.now();var i=(o||{}).formatters,s=void 0===i?{getDateTimeFormat:P(Intl.DateTimeFormat),getNumberFormat:P(Intl.NumberFormat),getMessageFormat:P(u),getRelativeFormat:P(f),getPluralFormat:P(Ge)}:i;return n.state=oe({},s,{now:function(){return n._didDisplay?Date.now():a}}),n}return ae(t,e),re(t,[{key:"getConfig",value:function(){var e=this.context.intl,t=v(this.props,Ye,e);for(var r in tt)void 0===t[r]&&(t[r]=tt[r]);if(!h(t.locale)){var n=t,o=n.locale,a=n.defaultLocale,i=n.defaultFormats;(0,n.onError)(w('Missing locale data for locale: "'+o+'". Using default locale: "'+a+'" as fallback.')),t=oe({},t,{locale:a,formats:i,messages:tt.messages})}return t}},{key:"getBoundFormatFns",value:function(e,t){return et.reduce(function(r,n){return r[n]=Xe[n].bind(null,e,t),r},{})}},{key:"getChildContext",value:function(){var e=this.getConfig(),t=this.getBoundFormatFns(e,this.state),r=this.state,n=r.now,o=ie(r,["now"]);return{intl:oe({},e,t,{formatters:o,now:n})}}},{key:"shouldComponentUpdate",value:function(){for(var e=arguments.length,t=Array(e),r=0;r<e;r++)t[r]=arguments[r];return b.apply(void 0,[this].concat(t))}},{key:"componentDidMount",value:function(){this._didDisplay=!0}},{key:"render",value:function(){return r.Children.only(this.props.children)}}]),t}(r.Component);rt.displayName="IntlProvider",rt.contextTypes={intl:xe},rt.childContextTypes={intl:xe.isRequired};var nt=function(e){function t(e,r){te(this,t);var n=se(this,(t.__proto__||Object.getPrototypeOf(t)).call(this,e,r));return g(r),n}return ae(t,e),re(t,[{key:"shouldComponentUpdate",value:function(){for(var e=arguments.length,t=Array(e),r=0;r<e;r++)t[r]=arguments[r];return b.apply(void 0,[this].concat(t))}},{key:"render",value:function(){var e=this.context.intl,t=e.formatDate,r=e.textComponent,n=this.props,o=n.value,a=n.children,i=t(o,this.props);return"function"==typeof a?a(i):D.createElement(r,null,i)}}]),t}(r.Component);nt.displayName="FormattedDate",nt.contextTypes={intl:xe};var ot=function(e){function t(e,r){te(this,t);var n=se(this,(t.__proto__||Object.getPrototypeOf(t)).call(this,e,r));return g(r),n}return ae(t,e),re(t,[{key:"shouldComponentUpdate",value:function(){for(var e=arguments.length,t=Array(e),r=0;r<e;r++)t[r]=arguments[r];return b.apply(void 0,[this].concat(t))}},{key:"render",value:function(){var e=this.context.intl,t=e.formatTime,r=e.textComponent,n=this.props,o=n.value,a=n.children,i=t(o,this.props);return"function"==typeof a?a(i):D.createElement(r,null,i)}}]),t}(r.Component);ot.displayName="FormattedTime",ot.contextTypes={intl:xe};var at=1e3,it=6e4,st=36e5,lt=864e5,ut=2147483647,ct=function(e){function t(e,r){te(this,t);var n=se(this,(t.__proto__||Object.getPrototypeOf(t)).call(this,e,r));g(r);var o=isFinite(e.initialNow)?Number(e.initialNow):r.intl.now();return n.state={now:o},n}return ae(t,e),re(t,[{key:"scheduleNextUpdate",value:function(e,t){var r=this;clearTimeout(this._timer);var n=e.value,o=e.units,a=e.updateInterval,i=new Date(n).getTime();if(a&&isFinite(i)){var s=i-t.now,l=M(o||A(s)),u=Math.abs(s%l),c=s<0?Math.max(a,l-u):Math.max(a,u);this._timer=setTimeout(function(){r.setState({now:r.context.intl.now()})},c)}}},{key:"componentDidMount",value:function(){this.scheduleNextUpdate(this.props,this.state)}},{key:"componentWillReceiveProps",value:function(e){R(e.value,this.props.value)||this.setState({now:this.context.intl.now()})}},{key:"shouldComponentUpdate",value:function(){for(var e=arguments.length,t=Array(e),r=0;r<e;r++)t[r]=arguments[r];return b.apply(void 0,[this].concat(t))}},{key:"componentWillUpdate",value:function(e,t){this.scheduleNextUpdate(e,t)}},{key:"componentWillUnmount",value:function(){clearTimeout(this._timer)}},{key:"render",value:function(){var e=this.context.intl,t=e.formatRelative,r=e.textComponent,n=this.props,o=n.value,a=n.children,i=t(o,oe({},this.props,this.state));return"function"==typeof a?a(i):D.createElement(r,null,i)}}]),t}(r.Component);ct.displayName="FormattedRelative",ct.contextTypes={intl:xe},ct.defaultProps={updateInterval:1e4};var ft=function(e){function t(e,r){te(this,t);var n=se(this,(t.__proto__||Object.getPrototypeOf(t)).call(this,e,r));return g(r),n}return ae(t,e),re(t,[{key:"shouldComponentUpdate",value:function(){for(var e=arguments.length,t=Array(e),r=0;r<e;r++)t[r]=arguments[r];return b.apply(void 0,[this].concat(t))}},{key:"render",value:function(){var e=this.context.intl,t=e.formatNumber,r=e.textComponent,n=this.props,o=n.value,a=n.children,i=t(o,this.props);return"function"==typeof a?a(i):D.createElement(r,null,i)}}]),t}(r.Component);ft.displayName="FormattedNumber",ft.contextTypes={intl:xe};var pt=function(e){function t(e,r){te(this,t);var n=se(this,(t.__proto__||Object.getPrototypeOf(t)).call(this,e,r));return g(r),n}return ae(t,e),re(t,[{key:"shouldComponentUpdate",value:function(){for(var e=arguments.length,t=Array(e),r=0;r<e;r++)t[r]=arguments[r];return b.apply(void 0,[this].concat(t))}},{key:"render",value:function(){var e=this.context.intl,t=e.formatPlural,r=e.textComponent,n=this.props,o=n.value,a=n.other,i=n.children,s=t(o,this.props),l=this.props[s]||a;return"function"==typeof i?i(l):D.createElement(r,null,l)}}]),t}(r.Component);pt.displayName="FormattedPlural",pt.contextTypes={intl:xe},pt.defaultProps={style:"cardinal"};var ht=function(e,t){return E({},{getMessageFormat:P(u)},e,t)},mt=function(e){function t(e,r){te(this,t);var n=se(this,(t.__proto__||Object.getPrototypeOf(t)).call(this,e,r));return e.defaultMessage||g(r),n}return ae(t,e),re(t,[{key:"shouldComponentUpdate",value:function(e){var t=this.props.values;if(!_(e.values,t))return!0;for(var r=oe({},e,{values:t}),n=arguments.length,o=Array(n>1?n-1:0),a=1;a<n;a++)o[a-1]=arguments[a];return b.apply(void 0,[this,r].concat(o))}},{key:"render",value:function(){var e=this.context.intl||{},t=e.formatMessage,n=void 0===t?ht:t,o=e.textComponent,a=void 0===o?"span":o,i=this.props,s=i.id,l=i.description,u=i.defaultMessage,c=i.values,f=i.tagName,p=void 0===f?a:f,h=i.children,m=void 0,d=void 0,y=void 0;if(c&&Object.keys(c).length>0){var v=Math.floor(1099511627776*Math.random()).toString(16),g=function(){var e=0;return function(){return"ELEMENT-"+v+"-"+(e+=1)}}();m="@__"+v+"__@",d={},y={},Object.keys(c).forEach(function(e){var t=c[e];if(r.isValidElement(t)){var n=g();d[e]=m+n+m,y[n]=t}else d[e]=t})}var _=n({id:s,description:l,defaultMessage:u},d||c),b=void 0;return b=y&&Object.keys(y).length>0?_.split(m).filter(function(e){return!!e}).map(function(e){return y[e]||e}):[_],"function"==typeof h?h.apply(void 0,le(b)):r.createElement.apply(void 0,[p,null].concat(le(b)))}}]),t}(r.Component);mt.displayName="FormattedMessage",mt.contextTypes={intl:xe},mt.defaultProps={values:{}};var dt=function(e){function t(e,r){te(this,t);var n=se(this,(t.__proto__||Object.getPrototypeOf(t)).call(this,e,r));return g(r),n}return ae(t,e),re(t,[{key:"shouldComponentUpdate",value:function(e){var t=this.props.values;if(!_(e.values,t))return!0;for(var r=oe({},e,{values:t}),n=arguments.length,o=Array(n>1?n-1:0),a=1;a<n;a++)o[a-1]=arguments[a];return b.apply(void 0,[this,r].concat(o))}},{key:"render",value:function(){var e=this.context.intl,t=e.formatHTMLMessage,r=e.textComponent,n=this.props,o=n.id,a=n.description,i=n.defaultMessage,s=n.values,l=n.tagName,u=void 0===l?r:l,c=n.children,f=t({id:o,description:a,defaultMessage:i},s);if("function"==typeof c)return c(f);var p={__html:f};return D.createElement(u,{dangerouslySetInnerHTML:p})}}]),t}(r.Component);dt.displayName="FormattedHTMLMessage",dt.contextTypes={intl:xe},dt.defaultProps={values:{}},p(I),e.addLocaleData=p,e.intlShape=xe,e.injectIntl=function(e){var t=arguments.length>1&&void 0!==arguments[1]?arguments[1]:{},n=t.intlPropName,o=void 0===n?"intl":n,a=t.withRef,i=void 0!==a&&a,s=function(t){function r(e,t){te(this,r);var n=se(this,(r.__proto__||Object.getPrototypeOf(r)).call(this,e,t));return g(t),n}return ae(r,t),re(r,[{key:"getWrappedInstance",value:function(){return Se(i,"[React Intl] To access the wrapped instance, the `{withRef: true}` option must be set when calling: `injectIntl()`"),this._wrappedInstance}},{key:"render",value:function(){var t=this;return D.createElement(e,oe({},this.props,ne({},o,this.context.intl),{ref:i?function(e){return t._wrappedInstance=e}:null}))}}]),r}(r.Component);return s.displayName="InjectIntl("+O(e)+")",s.contextTypes={intl:xe},s.WrappedComponent=e,Le(s,e)},e.defineMessages=function(e){return e},e.IntlProvider=rt,e.FormattedDate=nt,e.FormattedTime=ot,e.FormattedRelative=ct,e.FormattedNumber=ft,e.FormattedPlural=pt,e.FormattedMessage=mt,e.FormattedHTMLMessage=dt,Object.defineProperty(e,"__esModule",{value:!0})});
-//# sourceMappingURL=react-intl.min.js.map
diff --git a/browser/components/newtab/webpack.system-addon.config.js b/browser/components/newtab/webpack.system-addon.config.js
index 4b7cb08c70..eea3415f03 100644
--- a/browser/components/newtab/webpack.system-addon.config.js
+++ b/browser/components/newtab/webpack.system-addon.config.js
@@ -49,7 +49,6 @@ module.exports = (env = {}) => ({
     "prop-types": "PropTypes",
     "react": "React",
     "react-dom": "ReactDOM",
-    "react-intl": "ReactIntl",
     "redux": "Redux",
     "react-redux": "ReactRedux",
   },
diff --git a/browser/components/protocolhandler/test/mochitest.ini b/browser/components/protocolhandler/test/mochitest.ini
index 27e6cae556..4ada8373cc 100644
--- a/browser/components/protocolhandler/test/mochitest.ini
+++ b/browser/components/protocolhandler/test/mochitest.ini
@@ -1,2 +1 @@
 [test_registerHandler.html]
-[test_registerHandler_disabled.html]
diff --git a/browser/components/protocolhandler/test/test_registerHandler_disabled.html b/browser/components/protocolhandler/test/test_registerHandler_disabled.html
deleted file mode 100644
index 58e3b8aab0..0000000000
--- a/browser/components/protocolhandler/test/test_registerHandler_disabled.html
+++ /dev/null
@@ -1,38 +0,0 @@
-<!DOCTYPE HTML>
-<html>
-<!--
-https://bugzilla.mozilla.org/show_bug.cgi?id=402788
--->
-<head>
-  <title>Test for Bug 1398169</title>
-  <script src="/tests/SimpleTest/SimpleTest.js"></script>
-  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
-</head>
-<body>
-<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1398169">Mozilla Bug 1398169</a>
-<p id="display"></p>
-<div id="content" style="display: none">
-  
-</div>
-<pre id="test">
-<script class="testbody" type="text/javascript">
-  SimpleTest.waitForExplicitFinish();
-
-  async function tests() {
-    await SpecialPowers.pushPrefEnv({
-      set: [
-        ["dom.registerContentHandler.enabled", false],
-        ["dom.registerProtocolHandler.insecure.enabled", false],
-      ],
-    });
-    ok(!navigator.registerContentHandler, "navigator.registerContentHandler should be undefined");
-    ok(!navigator.registerProtocolHandler, "navigator.registerProtocolHandler should be undefined");
-    SimpleTest.finish();
-  }
-
-  tests();
-
-</script>
-</pre>
-</body>
-</html>
diff --git a/browser/components/sessionstore/SessionFile.jsm b/browser/components/sessionstore/SessionFile.jsm
index f4a9c22e51..2d1a77bb63 100644
--- a/browser/components/sessionstore/SessionFile.jsm
+++ b/browser/components/sessionstore/SessionFile.jsm
@@ -43,7 +43,6 @@ XPCOMUtils.defineLazyServiceGetter(
 
 XPCOMUtils.defineLazyModuleGetters(this, {
   RunState: "resource:///modules/sessionstore/RunState.jsm",
-  SessionStartup: "resource:///modules/sessionstore/SessionStartup.jsm",
   SessionStore: "resource:///modules/sessionstore/SessionStore.jsm",
   SessionWorker: "resource:///modules/sessionstore/SessionWorker.jsm",
 });
@@ -442,8 +441,7 @@ var SessionFileInternal = {
       RunState.setClosed();
     }
 
-    let performShutdownCleanup =
-      isFinalWrite && !SessionStartup.isAutomaticRestoreEnabled();
+    let performShutdownCleanup = isFinalWrite && !SessionStore.willAutoRestore;
 
     this._attempts++;
     let options = { isFinalWrite, performShutdownCleanup };
diff --git a/browser/components/sessionstore/SessionStartup.jsm b/browser/components/sessionstore/SessionStartup.jsm
index 479ff8a83e..206702c4ff 100644
--- a/browser/components/sessionstore/SessionStartup.jsm
+++ b/browser/components/sessionstore/SessionStartup.jsm
@@ -66,15 +66,15 @@ const TYPE_DEFER_SESSION = 3;
 // 'browser.startup.page' preference value to resume the previous session.
 const BROWSER_STARTUP_RESUME_SESSION = 3;
 
-function warning(aMsg, aException) {
+function warning(msg, exception) {
   let consoleMsg = Cc["@mozilla.org/scripterror;1"].createInstance(
     Ci.nsIScriptError
   );
   consoleMsg.init(
-    aMsg,
-    aException.fileName,
+    msg,
+    exception.fileName,
     null,
-    aException.lineNumber,
+    exception.lineNumber,
     0,
     Ci.nsIScriptError.warningFlag,
     "component javascript"
@@ -101,9 +101,9 @@ var SessionStartup = {
   RESUME_SESSION: TYPE_RESUME_SESSION,
   DEFER_SESSION: TYPE_DEFER_SESSION,
 
-  // the state to restore at startup
+  // The state to restore at startup.
   _initialState: null,
-  _sessionType: TYPE_NO_SESSION,
+  _sessionType: null,
   _initialized: false,
 
   // Stores whether the previous session crashed.
@@ -116,7 +116,7 @@ var SessionStartup = {
   /**
    * Initialize the component
    */
-  init: function sss_init() {
+  init() {
     Services.obs.notifyObservers(null, "sessionstore-init-started");
     StartupPerformance.init();
 
@@ -148,25 +148,20 @@ var SessionStartup = {
       );
     }
 
-    this._resumeSessionEnabled =
-      Services.prefs.getBoolPref("browser.sessionstore.resume_session_once") ||
-      Services.prefs.getIntPref("browser.startup.page") ==
-        BROWSER_STARTUP_RESUME_SESSION;
-
     SessionFile.read().then(this._onSessionFileRead.bind(this), console.error);
   },
 
-  // Wrap a string as a nsISupports
-  _createSupportsString: function ssfi_createSupportsString(aData) {
+  // Wrap a string as a nsISupports.
+  _createSupportsString(data) {
     let string = Cc["@mozilla.org/supports-string;1"].createInstance(
       Ci.nsISupportsString
     );
-    string.data = aData;
+    string.data = data;
     return string;
   },
 
   /**
-   * Complete initialization once the Session File has been read
+   * Complete initialization once the Session File has been read.
    *
    * @param source The Session State string read from disk.
    * @param parsed The object obtained by parsing |source| as JSON.
@@ -220,15 +215,11 @@ var SessionStartup = {
       );
     }, 60000);
 
-    // If this is a normal restore then throw away any previous session
-    if (!this._resumeSessionEnabled && this._initialState) {
+    // If this is a normal restore then throw away any previous session.
+    if (!this.isAutomaticRestoreEnabled() && this._initialState) {
       delete this._initialState.lastSessionState;
     }
 
-    let resumeFromCrash = Services.prefs.getBoolPref(
-      "browser.sessionstore.resume_from_crash"
-    );
-
     CrashMonitor.previousCheckpoints.then(checkpoints => {
       if (checkpoints) {
         // If the previous session finished writing the final state, we'll
@@ -242,7 +233,7 @@ var SessionStartup = {
         // a version including the Crash Monitor, or if the checkpoints file
         // was removed, or on first startup with this profile, or after Firefox Reset.
 
-        // There was no checkpoints file and no sessionstore.js or its backups
+        // There was no checkpoints file and no sessionstore.js or its backups,
         // so we will assume that this was a fresh profile.
         this._previousSessionCrashed = false;
       } else {
@@ -270,19 +261,11 @@ var SessionStartup = {
         .getHistogramById("SHUTDOWN_OK")
         .add(!this._previousSessionCrashed);
 
-      // set the startup type
-      if (this._previousSessionCrashed && resumeFromCrash) {
-        this._sessionType = this.RECOVER_SESSION;
-      } else if (!this._previousSessionCrashed && this._resumeSessionEnabled) {
-        this._sessionType = this.RESUME_SESSION;
-      } else if (this._initialState) {
-        this._sessionType = this.DEFER_SESSION;
-      } else {
-        this._initialState = null;
-      } // reset the state
       Services.obs.addObserver(this, "sessionstore-windows-restored", true);
 
-      if (this._sessionType != this.NO_SESSION) {
+      if (this.sessionType == this.NO_SESSION) {
+        this._initialState = null; // Reset the state.
+      } else {
         Services.obs.addObserver(this, "browser:purge-session-history", true);
       }
 
@@ -296,17 +279,17 @@ var SessionStartup = {
   /**
    * Handle notifications
    */
-  observe: function sss_observe(aSubject, aTopic, aData) {
-    switch (aTopic) {
+  observe(subject, topic, data) {
+    switch (topic) {
       case "sessionstore-windows-restored":
         Services.obs.removeObserver(this, "sessionstore-windows-restored");
-        // free _initialState after nsSessionStore is done with it
+        // Free _initialState after nsSessionStore is done with it.
         this._initialState = null;
         this._didRestore = true;
         break;
       case "browser:purge-session-history":
         Services.obs.removeObserver(this, "browser:purge-session-history");
-        // reset all state on sanitization
+        // Reset all state on sanitization.
         this._sessionType = this.NO_SESSION;
         break;
     }
@@ -325,15 +308,6 @@ var SessionStartup = {
     return this._initialState;
   },
 
-  /**
-   * Determines whether there is a pending session restore. Should only be
-   * called after initialization has completed.
-   * @returns bool
-   */
-  doRestore: function sss_doRestore() {
-    return this._willRestore();
-  },
-
   /**
    * Determines whether automatic session restoration is enabled for this
    * launch of the browser. This does not include crash restoration. In
@@ -342,28 +316,39 @@ var SessionStartup = {
    * @returns bool
    */
   isAutomaticRestoreEnabled() {
-    if (PrivateBrowsingUtils.permanentPrivateBrowsing) {
-      return false;
+    if (this._resumeSessionEnabled === null) {
+      this._resumeSessionEnabled =
+        !PrivateBrowsingUtils.permanentPrivateBrowsing &&
+        (Services.prefs.getBoolPref(
+          "browser.sessionstore.resume_session_once"
+        ) ||
+          Services.prefs.getIntPref("browser.startup.page") ==
+            BROWSER_STARTUP_RESUME_SESSION);
     }
 
-    return (
-      Services.prefs.getBoolPref("browser.sessionstore.resume_session_once") ||
-      Services.prefs.getIntPref("browser.startup.page") ==
-        BROWSER_STARTUP_RESUME_SESSION
-    );
+    return this._resumeSessionEnabled;
   },
 
   /**
    * Determines whether there is a pending session restore.
    * @returns bool
    */
-  _willRestore() {
+  willRestore() {
     return (
-      this._sessionType == this.RECOVER_SESSION ||
-      this._sessionType == this.RESUME_SESSION
+      this.sessionType == this.RECOVER_SESSION ||
+      this.sessionType == this.RESUME_SESSION
     );
   },
 
+  /**
+   * Determines whether there is a pending session restore and if that will refer
+   * back to a crash.
+   * @returns bool
+   */
+  willRestoreAsCrashed() {
+    return this.sessionType == this.RECOVER_SESSION;
+  },
+
   /**
    * Returns a boolean or a promise that resolves to a boolean, indicating
    * whether we will restore a session that ends up replacing the homepage.
@@ -378,7 +363,7 @@ var SessionStartup = {
     // it when recovering from a crash, which we'll only know after reading the
     // session file, but waiting for that would delay loading the homepage in
     // the non-crash case.
-    if (!this._initialState && !this._resumeSessionEnabled) {
+    if (!this._initialState && !this.isAutomaticRestoreEnabled()) {
       return false;
     }
     // If we've already restored the session, we won't override again.
@@ -391,7 +376,7 @@ var SessionStartup = {
         // If there are valid windows with not only pinned tabs, signal that we
         // will override the default homepage by restoring a session.
         resolve(
-          this._willRestore() &&
+          this.willRestore() &&
             this._initialState &&
             this._initialState.windows &&
             this._initialState.windows.some(w => w.tabs.some(t => !t.pinned))
@@ -404,6 +389,22 @@ var SessionStartup = {
    * Get the type of pending session store, if any.
    */
   get sessionType() {
+    if (this._sessionType === null) {
+      let resumeFromCrash = Services.prefs.getBoolPref(
+        "browser.sessionstore.resume_from_crash"
+      );
+      // Set the startup type.
+      if (this.isAutomaticRestoreEnabled()) {
+        this._sessionType = this.RESUME_SESSION;
+      } else if (this._previousSessionCrashed && resumeFromCrash) {
+        this._sessionType = this.RECOVER_SESSION;
+      } else if (this._initialState) {
+        this._sessionType = this.DEFER_SESSION;
+      } else {
+        this._sessionType = this.NO_SESSION;
+      }
+    }
+
     return this._sessionType;
   },
 
@@ -414,6 +415,11 @@ var SessionStartup = {
     return this._previousSessionCrashed;
   },
 
+  resetForTest() {
+    this._resumeSessionEnabled = null;
+    this._sessionType = null;
+  },
+
   QueryInterface: ChromeUtils.generateQI([
     Ci.nsIObserver,
     Ci.nsISupportsWeakReference,
diff --git a/browser/components/sessionstore/SessionStore.jsm b/browser/components/sessionstore/SessionStore.jsm
index 30dbd8f12f..2ba91e981e 100644
--- a/browser/components/sessionstore/SessionStore.jsm
+++ b/browser/components/sessionstore/SessionStore.jsm
@@ -172,6 +172,9 @@ const RESTORE_TAB_CONTENT_REASON = {
   NAVIGATE_AND_RESTORE: 1,
 };
 
+// 'browser.startup.page' preference value to resume the previous session.
+const BROWSER_STARTUP_RESUME_SESSION = 3;
+
 ChromeUtils.import("resource://gre/modules/PrivateBrowsingUtils.jsm", this);
 ChromeUtils.import("resource://gre/modules/Services.jsm", this);
 ChromeUtils.import("resource://gre/modules/TelemetryTimestamps.jsm", this);
@@ -250,6 +253,10 @@ var SessionStore = {
     return SessionStoreInternal.lastClosedObjectType;
   },
 
+  get willAutoRestore() {
+    return SessionStoreInternal.willAutoRestore;
+  },
+
   init: function ss_init() {
     SessionStoreInternal.init();
   },
@@ -655,6 +662,19 @@ var SessionStoreInternal = {
     return "tab";
   },
 
+  /**
+   * Returns a boolean that determines whether the session will be automatically
+   * restored upon the _next_ startup or a restart.
+   */
+  get willAutoRestore() {
+    return (
+      !PrivateBrowsingUtils.permanentPrivateBrowsing &&
+      (Services.prefs.getBoolPref("browser.sessionstore.resume_session_once") ||
+        Services.prefs.getIntPref("browser.startup.page") ==
+          BROWSER_STARTUP_RESUME_SESSION)
+    );
+  },
+
   /**
    * Initialize the sessionstore service.
    */
@@ -684,7 +704,7 @@ var SessionStoreInternal = {
     let state;
     let ss = SessionStartup;
 
-    if (ss.doRestore() || ss.sessionType == ss.DEFER_SESSION) {
+    if (ss.willRestore() || ss.sessionType == ss.DEFER_SESSION) {
       state = ss.state;
     }
 
@@ -716,7 +736,7 @@ var SessionStoreInternal = {
           // restore it
           LastSession.setState(state.lastSessionState);
 
-          if (ss.previousSessionCrashed) {
+          if (ss.willRestoreAsCrashed()) {
             this._recentCrashes =
               ((state.session && state.session.recentCrashes) || 0) + 1;
 
@@ -1372,7 +1392,10 @@ var SessionStoreInternal = {
 
       if (closedWindowState) {
         let newWindowState;
-        if (AppConstants.platform == "macosx" || !this._doResumeSession()) {
+        if (
+          AppConstants.platform == "macosx" ||
+          !SessionStartup.willRestore()
+        ) {
           // We want to split the window up into pinned tabs and unpinned tabs.
           // Pinned tabs should be restored. If there are any remaining tabs,
           // they should be added back to _closedWindows.
@@ -5164,17 +5187,6 @@ var SessionStoreInternal = {
     return window;
   },
 
-  /**
-   * Whether or not to resume session, if not recovering from a crash.
-   * @returns bool
-   */
-  _doResumeSession: function ssi_doResumeSession() {
-    return (
-      this._prefBranch.getIntPref("startup.page") == 3 ||
-      this._prefBranch.getBoolPref("sessionstore.resume_session_once")
-    );
-  },
-
   /**
    * whether the user wants to load any other page at startup
    * (except the homepage) - needed for determining whether to overwrite the current tabs
diff --git a/browser/components/sessionstore/test/browser_354894_perwindowpb.js b/browser/components/sessionstore/test/browser_354894_perwindowpb.js
index 97391eea18..b13c08ced3 100644
--- a/browser/components/sessionstore/test/browser_354894_perwindowpb.js
+++ b/browser/components/sessionstore/test/browser_354894_perwindowpb.js
@@ -24,6 +24,7 @@
  * notifications. The latter won't.
  */
 
+ChromeUtils.import("resource:///modules/sessionstore/SessionStartup.jsm", this);
 // The rejection "BrowserWindowTracker.getTopWindow(...) is null" is left
 // unhandled in some cases. This bug should be fixed, but for the moment this
 // file is whitelisted.
@@ -115,6 +116,9 @@ let setupTest = async function(options, testFunction) {
     ["browser.startup.page", 3],
     ["browser.tabs.warnOnClose", false]
   );
+  // SessionStartup caches pref values, but as this test tries to simulate a
+  // startup scenario, we'll reset them here.
+  SessionStartup.resetForTest();
 
   // Observe these, and also use to count the number of hits
   let observing = {
@@ -156,6 +160,8 @@ let setupTest = async function(options, testFunction) {
   }
 
   await popPrefs();
+  // Act like nothing ever happened.
+  SessionStartup.resetForTest();
 };
 
 /**
diff --git a/browser/components/sessionstore/test/browser_background_tab_crash.js b/browser/components/sessionstore/test/browser_background_tab_crash.js
index 2cff8dfbc1..c42718054f 100644
--- a/browser/components/sessionstore/test/browser_background_tab_crash.js
+++ b/browser/components/sessionstore/test/browser_background_tab_crash.js
@@ -244,7 +244,7 @@ add_task(async function test_preload_crash() {
   NewTabPagePreloading.removePreloadedBrowser(window);
 
   // Create a fresh preloaded browser
-  NewTabPagePreloading.maybeCreatePreloadedBrowser(window);
+  await BrowserTestUtils.maybeCreatePreloadedBrowser(gBrowser);
 
   await BrowserTestUtils.crashBrowser(gBrowser.preloadedBrowser, false);
 
diff --git a/browser/config/version.txt b/browser/config/version.txt
index cf1f85ecfa..7489cae399 100644
--- a/browser/config/version.txt
+++ b/browser/config/version.txt
@@ -1 +1 @@
-68.13.9
+68.14.0
diff --git a/browser/config/version_display.txt b/browser/config/version_display.txt
index e3c65f1127..10247aeb1e 100644
--- a/browser/config/version_display.txt
+++ b/browser/config/version_display.txt
@@ -1 +1 @@
-68.13.9b
+68.14.0b
diff --git a/browser/installer/package-manifest.in b/browser/installer/package-manifest.in
index a26a220795..06f2aabebc 100644
--- a/browser/installer/package-manifest.in
+++ b/browser/installer/package-manifest.in
@@ -167,9 +167,6 @@
 
 ; JavaScript components
 @RESPATH@/browser/components/BrowserComponents.manifest
-@RESPATH@/components/EnterprisePolicies.js
-@RESPATH@/components/EnterprisePoliciesContent.js
-@RESPATH@/components/EnterprisePolicies.manifest
 @RESPATH@/components/extensions.manifest
 #ifdef MOZ_UPDATER
 @RESPATH@/components/nsUpdateService.manifest
@@ -263,17 +260,14 @@
 ; [Webide Files]
 @RESPATH@/browser/chrome/webide@JAREXT@
 @RESPATH@/browser/chrome/webide.manifest
-@RESPATH@/browser/@PREF_DIR@/webide.js
 
 ; [DevTools Startup Files]
 @RESPATH@/browser/chrome/devtools-startup@JAREXT@
 @RESPATH@/browser/chrome/devtools-startup.manifest
-@RESPATH@/browser/@PREF_DIR@/devtools-startup.js
 
 ; DevTools
 @RESPATH@/browser/chrome/devtools@JAREXT@
 @RESPATH@/browser/chrome/devtools.manifest
-@RESPATH@/browser/@PREF_DIR@/devtools-client.js
 @RESPATH@/browser/@PREF_DIR@/debugger.js
 
 ; shell icons
diff --git a/caps/BasePrincipal.cpp b/caps/BasePrincipal.cpp
index b0704a9544..53d6d9dfcb 100644
--- a/caps/BasePrincipal.cpp
+++ b/caps/BasePrincipal.cpp
@@ -915,6 +915,21 @@ BasePrincipal::GetLocalStorageQuotaKey(nsACString& aKey) {
   return NS_OK;
 }
 
+NS_IMETHODIMP
+BasePrincipal::GetIsScriptAllowedByPolicy(bool* aIsScriptAllowedByPolicy) {
+  *aIsScriptAllowedByPolicy = false;
+  nsCOMPtr<nsIURI> prinURI;
+  nsresult rv = GetURI(getter_AddRefs(prinURI));
+  if (NS_FAILED(rv) || !prinURI) {
+    return NS_OK;
+  }
+  nsIScriptSecurityManager* ssm = nsContentUtils::GetSecurityManager();
+  if (!ssm) {
+    return NS_ERROR_UNEXPECTED;
+  }
+  return ssm->PolicyAllowsScript(prinURI, aIsScriptAllowedByPolicy);
+}
+
 bool SiteIdentifier::Equals(const SiteIdentifier& aOther) const {
   MOZ_ASSERT(IsInitialized());
   MOZ_ASSERT(aOther.IsInitialized());
diff --git a/caps/BasePrincipal.h b/caps/BasePrincipal.h
index fde5359273..cb638642f1 100644
--- a/caps/BasePrincipal.h
+++ b/caps/BasePrincipal.h
@@ -146,7 +146,9 @@ class BasePrincipal : public nsJSPrincipals {
   NS_IMETHOD AllowsRelaxStrictFileOriginPolicy(nsIURI* aURI,
                                                bool* aRes) override;
   NS_IMETHOD CreateReferrerInfo(mozilla::dom::ReferrerPolicy aReferrerPolicy,
-                                  nsIReferrerInfo** _retval) override;
+                                nsIReferrerInfo** _retval) override;
+  NS_IMETHOD GetIsScriptAllowedByPolicy(
+      bool* aIsScriptAllowedByPolicy) override;
   nsresult ToJSON(nsACString& aJSON);
   static already_AddRefed<BasePrincipal> FromJSON(const nsACString& aJSON);
   // Method populates a passed Json::Value with serializable fields
diff --git a/caps/ContentPrincipal.cpp b/caps/ContentPrincipal.cpp
index 63f2c94518..c23d9467a6 100644
--- a/caps/ContentPrincipal.cpp
+++ b/caps/ContentPrincipal.cpp
@@ -353,14 +353,17 @@ ContentPrincipal::SetDomain(nsIURI* aDomain) {
 
   // Set the changed-document-domain flag on compartments containing realms
   // using this principal.
-  auto cb = [](JSContext*, void*, JS::Handle<JS::Realm*> aRealm) {
+  auto cb = [](JSContext*, void*, JS::Realm* aRealm,
+               const JS::AutoRequireNoGC& nogc) {
     JS::Compartment* comp = JS::GetCompartmentForRealm(aRealm);
     xpc::SetCompartmentChangedDocumentDomain(comp);
   };
   JSPrincipals* principals =
       nsJSPrincipals::get(static_cast<nsIPrincipal*>(this));
-  AutoSafeJSContext cx;
-  JS::IterateRealmsWithPrincipals(cx, principals, nullptr, cb);
+
+  dom::AutoJSAPI jsapi;
+  jsapi.Init();
+  JS::IterateRealmsWithPrincipals(jsapi.cx(), principals, nullptr, cb);
 
   return NS_OK;
 }
diff --git a/caps/nsIPrincipal.idl b/caps/nsIPrincipal.idl
index 626c9d830c..5d82ddf27f 100644
--- a/caps/nsIPrincipal.idl
+++ b/caps/nsIPrincipal.idl
@@ -430,6 +430,12 @@ interface nsIPrincipal : nsISerializable
     * Returns true if the URI is an Onion URI
     */
     [infallible] readonly attribute boolean isOnion;
+
+    /*
+     * Returns true if the Domain Policy allows js execution
+     * for the Principals URI
+     */
+    readonly attribute boolean isScriptAllowedByPolicy;
 };
 
 /**
diff --git a/config/check_spidermonkey_style.py b/config/check_spidermonkey_style.py
index 3e51350c35..a609677dcd 100644
--- a/config/check_spidermonkey_style.py
+++ b/config/check_spidermonkey_style.py
@@ -60,6 +60,7 @@ included_inclnames_to_ignore = set([
     'double-conversion/double-conversion.h',  # strange MFBT case
     'javascript-trace.h',       # generated in $OBJDIR if HAVE_DTRACE is defined
     'frontend/ReservedWordsGenerated.h',  # generated in $OBJDIR
+    'frontend/smoosh_generated.h',        # generated in $OBJDIR
     'gc/StatsPhasesGenerated.h',         # generated in $OBJDIR
     'gc/StatsPhasesGenerated.inc',       # generated in $OBJDIR
     'jit/CacheIROpsGenerated.h',         # generated in $OBJDIR
@@ -96,6 +97,7 @@ included_inclnames_to_ignore = set([
     'unicode/ucurr.h',          # ICU
     'unicode/udat.h',           # ICU
     'unicode/udata.h',          # ICU
+    'unicode/udateintervalformat.h',  # ICU
     'unicode/udatpg.h',         # ICU
     'unicode/udisplaycontext.h',  # ICU
     'unicode/uenum.h',          # ICU
@@ -301,7 +303,7 @@ def check_style(enable_fixup):
     js_public_root = os.path.join('js', 'public')
     for dirpath, dirnames, filenames in os.walk(js_public_root):
         for filename in filenames:
-            if filename.endswith('.h'):
+            if filename.endswith(('.h', '.msg')):
                 filepath = os.path.join(dirpath, filename).replace('\\', '/')
                 inclname = 'js/' + filepath[len('js/public/'):]
                 js_names[filepath] = inclname
@@ -362,12 +364,21 @@ def is_module_header(enclosing_inclname, header_inclname):
 
     module = module_name(enclosing_inclname)
 
-    # Normal case, e.g. module == "foo/Bar", header_inclname == "foo/Bar.h".
+    # Normal case, for example:
+    #   module == "vm/Runtime", header_inclname == "vm/Runtime.h".
     if module == module_name(header_inclname):
         return True
 
-    # A public header, e.g. module == "foo/Bar", header_inclname == "js/Bar.h".
-    m = re.match(r'js\/(.*)\.h', header_inclname)
+    # A public header, for example:
+    #
+    #   module == "vm/CharacterEncoding",
+    #   header_inclname == "js/CharacterEncoding.h"
+    #
+    # or (for implementation files for js/public/*/*.h headers)
+    #
+    #   module == "vm/SourceHook",
+    #   header_inclname == "js/experimental/SourceHook.h"
+    m = re.match(r'js\/.*?([^\/]+)\.h', header_inclname)
     if m is not None and module.endswith('/' + m.group(1)):
         return True
 
@@ -400,7 +411,7 @@ class Include(object):
           4. foo/Bar.h
           5. jsfooinlines.h
           6. foo/Bar-inl.h
-          7. non-.h, e.g. *.tbl, *.msg
+          7. non-.h, e.g. *.tbl, *.msg (these can be scattered throughout files)
         '''
 
         if self.is_system:
diff --git a/config/external/icu/i18n/sources.mozbuild b/config/external/icu/i18n/sources.mozbuild
index be7f29f629..3cef96e2e4 100644
--- a/config/external/icu/i18n/sources.mozbuild
+++ b/config/external/icu/i18n/sources.mozbuild
@@ -157,6 +157,7 @@ SOURCES += [
    '/intl/icu/source/i18n/ucol_sit.cpp',
    '/intl/icu/source/i18n/ucoleitr.cpp',
    '/intl/icu/source/i18n/udat.cpp',
+   '/intl/icu/source/i18n/udateintervalformat.cpp',
    '/intl/icu/source/i18n/udatpg.cpp',
    '/intl/icu/source/i18n/ufieldpositer.cpp',
    '/intl/icu/source/i18n/uitercollationiterator.cpp',
diff --git a/config/makefiles/xpidl/Makefile.in b/config/makefiles/xpidl/Makefile.in
index 33e450c8a7..17a79fde76 100644
--- a/config/makefiles/xpidl/Makefile.in
+++ b/config/makefiles/xpidl/Makefile.in
@@ -29,8 +29,11 @@ idl_deps_dir := .deps
 dist_idl_dir := $(DIST)/idl
 dist_include_dir := $(DIST)/include
 dist_xpcrs_dir := $(DIST)/xpcrs
+stub_file := xptdata.stub
 process_py := $(topsrcdir)/python/mozbuild/mozbuild/action/xpidl-process.py
-generated_file := $(topobjdir)/xpcom/reflect/xptinfo/xptdata.cpp
+target_file := $(topobjdir)/xpcom/reflect/xptinfo/xptdata.cpp
+xptdata_h := $(dist_include_dir)/xptdata.h
+generated_files := $(target_file) $(xptdata_h)
 code_gen_py := $(topsrcdir)/xpcom/reflect/xptinfo/xptcodegen.py
 code_gen_deps := $(topsrcdir)/xpcom/ds/tools/perfecthash.py
 
@@ -60,17 +63,21 @@ xpt_files := $(addsuffix .xpt,$(xpidl_modules))
 
 depends_files := $(foreach root,$(xpidl_modules),$(idl_deps_dir)/$(root).pp)
 
-GARBAGE += $(xpt_files) $(depends_files) $(generated_file)
+GARBAGE += $(stub_file) $(xpt_files) $(depends_files) $(target_file)
 
 ifdef COMPILE_ENVIRONMENT
-xpidl:: $(generated_file)
+xpidl:: $(generated_files)
 endif
 
+# See bug 1420119 for why we need the semicolon.
+$(target_file) $(xptdata_h) : $(stub_file) ;
+
 $(xpt_files): $(process_py) $(call mkdir_deps,$(idl_deps_dir) $(dist_include_dir) $(dist_xpcrs_dir))
 
-$(generated_file): $(xpt_files) $(code_gen_py) $(code_gen_deps)
+$(stub_file) : $(xpt_files) $(code_gen_py) $(code_gen_deps)
 	$(REPORT_BUILD)
-	$(PYTHON_PATH) $(PLY_INCLUDE) $(code_gen_py) $(generated_file) $(xpt_files)
+	$(PYTHON_PATH) $(PLY_INCLUDE) $(code_gen_py) $(generated_files) $(xpt_files)
+	@touch $@
 
 -include $(depends_files)
 
diff --git a/config/recurse.mk b/config/recurse.mk
index 3ad1d68759..d45af11a48 100644
--- a/config/recurse.mk
+++ b/config/recurse.mk
@@ -182,12 +182,17 @@ xpcom/xpidl/export: xpcom/idl-parser/xpidl/export
 dom/bindings/export: layout/style/export
 
 ifdef ENABLE_CLANG_PLUGIN
-$(filter-out config/host build/unix/stdc++compat/% build/clang-plugin/%,$(compile_targets)): build/clang-plugin/host build/clang-plugin/tests/target-objects
+# Only target rules use the clang plugin.
+$(filter %/target %/target-objects,$(filter-out config/export config/host build/unix/stdc++compat/% build/clang-plugin/%,$(compile_targets))): build/clang-plugin/host build/clang-plugin/tests/target-objects
 build/clang-plugin/tests/target-objects: build/clang-plugin/host
 # clang-plugin tests require js-confdefs.h on js standalone builds and mozilla-config.h on
 # other builds, because they are -include'd.
 ifdef JS_STANDALONE
+# The js/src/export target only exists when CURRENT_TIER is export. If we're in a later tier,
+# we can assume js/src/export has happened anyways.
+ifeq ($(CURRENT_TIER),export)
 build/clang-plugin/tests/target-objects: js/src/export
+endif
 else
 build/clang-plugin/tests/target-objects: mozilla-config.h
 endif
diff --git a/config/system-headers.mozbuild b/config/system-headers.mozbuild
index ce57d0abbe..9a00f9cde5 100644
--- a/config/system-headers.mozbuild
+++ b/config/system-headers.mozbuild
@@ -1327,6 +1327,7 @@ if CONFIG['MOZ_SYSTEM_ICU']:
         'unicode/ucurr.h',
         'unicode/udat.h',
         'unicode/udata.h',
+        'unicode/udateintervalformat.h',
         'unicode/udatpg.h',
         'unicode/udisplaycontext.h',
         'unicode/uldnames.h',
diff --git a/docshell/base/BrowsingContext.cpp b/docshell/base/BrowsingContext.cpp
index 14afa14f82..608d7e52b4 100644
--- a/docshell/base/BrowsingContext.cpp
+++ b/docshell/base/BrowsingContext.cpp
@@ -599,7 +599,7 @@ class RemoteLocationProxy
     auto location =
         static_cast<BrowsingContext::LocationProxy*>(GetNative(aProxy));
     CycleCollectionNoteChild(aCb, location->GetBrowsingContext(),
-                             "js::GetObjectPrivate(obj)->GetBrowsingContext()");
+                             "JS::GetPrivate(obj)->GetBrowsingContext()");
   }
 };
 
diff --git a/docshell/base/nsDefaultURIFixup.cpp b/docshell/base/nsDefaultURIFixup.cpp
index 17b7eac5e2..346080adcf 100644
--- a/docshell/base/nsDefaultURIFixup.cpp
+++ b/docshell/base/nsDefaultURIFixup.cpp
@@ -711,13 +711,13 @@ bool nsDefaultURIFixup::PossiblyHostPortUrl(const nsACString& aUrl) {
   ++iter;
 
   // Count the number of digits after the colon and before the
-  // next forward slash (or end of string)
+  // next forward slash, question mark, hash sign, or end of string.
 
   uint32_t digitCount = 0;
   while (iter != iterEnd && digitCount <= 5) {
     if (IsAsciiDigit(*iter)) {
       digitCount++;
-    } else if (*iter == '/') {
+    } else if (*iter == '/' || *iter == '?' || *iter == '#') {
       break;
     } else {
       // Whatever it is, it ain't a port!
diff --git a/docshell/base/timeline/AutoGlobalTimelineMarker.cpp b/docshell/base/timeline/AutoGlobalTimelineMarker.cpp
index aff730f782..cfe3ce8f1c 100644
--- a/docshell/base/timeline/AutoGlobalTimelineMarker.cpp
+++ b/docshell/base/timeline/AutoGlobalTimelineMarker.cpp
@@ -11,9 +11,8 @@ namespace mozilla {
 
 AutoGlobalTimelineMarker::AutoGlobalTimelineMarker(
     const char* aName, MarkerStackRequest aStackRequest /* = STACK */
-                           MOZ_GUARD_OBJECT_NOTIFIER_PARAM_IN_IMPL)
+    )
     : mName(aName), mStackRequest(aStackRequest) {
-  MOZ_GUARD_OBJECT_NOTIFIER_INIT;
   MOZ_ASSERT(NS_IsMainThread());
 
   RefPtr<TimelineConsumers> timelines = TimelineConsumers::Get();
diff --git a/docshell/base/timeline/AutoGlobalTimelineMarker.h b/docshell/base/timeline/AutoGlobalTimelineMarker.h
index 21465e7e5b..4ec7c4e391 100644
--- a/docshell/base/timeline/AutoGlobalTimelineMarker.h
+++ b/docshell/base/timeline/AutoGlobalTimelineMarker.h
@@ -5,7 +5,6 @@
 #ifndef mozilla_AutoGlobalTimelineMarker_h_
 #define mozilla_AutoGlobalTimelineMarker_h_
 
-#include "mozilla/GuardObjects.h"
 #include "TimelineMarkerEnums.h"
 
 namespace mozilla {
@@ -26,7 +25,6 @@ namespace mozilla {
 //       ...
 //     }
 class MOZ_RAII AutoGlobalTimelineMarker {
-  MOZ_DECL_USE_GUARD_OBJECT_NOTIFIER;
 
   // The name of the marker we are adding.
   const char* mName;
@@ -36,8 +34,7 @@ class MOZ_RAII AutoGlobalTimelineMarker {
  public:
   explicit AutoGlobalTimelineMarker(
       const char* aName,
-      MarkerStackRequest aStackRequest =
-          MarkerStackRequest::STACK MOZ_GUARD_OBJECT_NOTIFIER_PARAM);
+      MarkerStackRequest aStackRequest = MarkerStackRequest::STACK);
   ~AutoGlobalTimelineMarker();
 
   AutoGlobalTimelineMarker(const AutoGlobalTimelineMarker& aOther) = delete;
diff --git a/docshell/base/timeline/ObservedDocShell.cpp b/docshell/base/timeline/ObservedDocShell.cpp
index 8be6caaf46..884fdef59a 100644
--- a/docshell/base/timeline/ObservedDocShell.cpp
+++ b/docshell/base/timeline/ObservedDocShell.cpp
@@ -159,7 +159,7 @@ void ObservedDocShell::PopMarkers(
     }
   }
 
-  mTimelineMarkers.SwapElements(keptStartMarkers);
+  mTimelineMarkers = std::move(keptStartMarkers);
 }
 
 }  // namespace mozilla
diff --git a/docshell/build/components.conf b/docshell/build/components.conf
index 63aeb0eb82..36889cf230 100644
--- a/docshell/build/components.conf
+++ b/docshell/build/components.conf
@@ -58,8 +58,10 @@ Classes = [
     },
     {
         'name': 'URIFixup',
+        'js_name': 'uriFixup',
         'cid': '{214c48a0-b57f-11d4-959c-0020183bf181}',
         'contract_ids': ['@mozilla.org/docshell/urifixup;1'],
+        'interfaces': ['nsIURIFixup'],
         'type': 'nsDefaultURIFixup',
         'headers': ['/docshell/base/nsDefaultURIFixup.h'],
     },
diff --git a/docshell/test/browser/browser_timelineMarkers-frame-04.js b/docshell/test/browser/browser_timelineMarkers-frame-04.js
index 29972be84b..a05804c5b3 100644
--- a/docshell/test/browser/browser_timelineMarkers-frame-04.js
+++ b/docshell/test/browser/browser_timelineMarkers-frame-04.js
@@ -41,7 +41,11 @@ var TESTS = [
   },
 ];
 
-if (Services.prefs.getBoolPref("javascript.options.asyncstack")) {
+if (
+  !Services.prefs.getBoolPref(
+    "javascript.options.asyncstack_capture_debuggee_only"
+  )
+) {
   TESTS.push(
     {
       desc: "Async stack trace on Javascript marker",
diff --git a/docshell/test/browser/browser_timelineMarkers-frame-05.js b/docshell/test/browser/browser_timelineMarkers-frame-05.js
index 266b2b5dd3..b5c245e451 100644
--- a/docshell/test/browser/browser_timelineMarkers-frame-05.js
+++ b/docshell/test/browser/browser_timelineMarkers-frame-05.js
@@ -97,7 +97,11 @@ var TESTS = [
   },
 ];
 
-if (Services.prefs.getBoolPref("javascript.options.asyncstack")) {
+if (
+  !Services.prefs.getBoolPref(
+    "javascript.options.asyncstack_capture_debuggee_only"
+  )
+) {
   TESTS.push({
     desc: "Async stack trace on Promise",
     searchFor: "ConsoleTime",
diff --git a/docshell/test/unit/test_nsDefaultURIFixup_search.js b/docshell/test/unit/test_nsDefaultURIFixup_search.js
index 20187ec4c2..0be452ddd7 100644
--- a/docshell/test/unit/test_nsDefaultURIFixup_search.js
+++ b/docshell/test/unit/test_nsDefaultURIFixup_search.js
@@ -71,6 +71,18 @@ var data = [
     wrong: "://user:pass@example.com:8080/this/is/a/test.html",
     fixed: "http://user:pass@example.com:8080/this/is/a/test.html",
   },
+  {
+    wrong: "localhost:8080/?param=1",
+    fixed: "http://localhost:8080/?param=1",
+  },
+  {
+    wrong: "localhost:8080?param=1",
+    fixed: "http://localhost:8080/?param=1",
+  },
+  {
+    wrong: "localhost:8080#somewhere",
+    fixed: "http://localhost:8080/#somewhere",
+  },
   {
     wrong: "whatever://this/is/a@b/test.html",
     fixed: kSearchEngineURL.replace(
diff --git a/editor/libeditor/EditorBase.cpp b/editor/libeditor/EditorBase.cpp
index c39e9b5348..7711c00534 100644
--- a/editor/libeditor/EditorBase.cpp
+++ b/editor/libeditor/EditorBase.cpp
@@ -29,7 +29,6 @@
 #include "mozilla/BasePrincipal.h"            // for BasePrincipal
 #include "mozilla/CheckedInt.h"               // for CheckedInt
 #include "mozilla/ComposerCommandsUpdater.h"  // for ComposerCommandsUpdater
-#include "mozilla/ComputedStyle.h"            // for ComputedStyle
 #include "mozilla/CSSEditUtils.h"             // for CSSEditUtils
 #include "mozilla/EditAction.h"               // for EditSubAction
 #include "mozilla/EditorDOMPoint.h"           // for EditorDOMPoint
@@ -78,7 +77,6 @@
 #include "nsCaseTreatment.h"
 #include "nsCharTraits.h"              // for NS_IS_HIGH_SURROGATE, etc.
 #include "nsComponentManagerUtils.h"   // for do_CreateInstance
-#include "nsComputedDOMStyle.h"        // for nsComputedDOMStyle
 #include "nsContentUtils.h"            // for nsContentUtils
 #include "nsDOMString.h"               // for DOMStringIsNull
 #include "nsDebug.h"                   // for NS_WARNING, etc.
@@ -126,6 +124,8 @@ namespace mozilla {
 using namespace dom;
 using namespace widget;
 
+using ChildBlockBoundary = HTMLEditUtils::ChildBlockBoundary;
+
 /*****************************************************************************
  * mozilla::EditorBase
  *****************************************************************************/
@@ -2585,7 +2585,8 @@ nsINode* EditorBase::GetFirstEditableNode(nsINode* aRoot) {
   MOZ_ASSERT(aRoot);
 
   EditorType editorType = GetEditorType();
-  nsIContent* content = GetLeftmostChild(aRoot);
+  nsIContent* content =
+      HTMLEditUtils::GetFirstLeafChild(*aRoot, ChildBlockBoundary::TreatAsLeaf);
   if (content && !EditorUtils::IsEditableContent(*content, editorType)) {
     content = GetNextEditableNode(*content);
   }
@@ -2815,7 +2816,7 @@ nsresult EditorBase::DeleteTextWithTransaction(Text& aTextNode,
   return rv;
 }
 
-nsIContent* EditorBase::GetPreviousNodeInternal(nsINode& aNode,
+nsIContent* EditorBase::GetPreviousNodeInternal(const nsINode& aNode,
                                                 bool aFindEditableNode,
                                                 bool aFindAnyDataNode,
                                                 bool aNoBlockCrossing) const {
@@ -2856,24 +2857,25 @@ nsIContent* EditorBase::GetPreviousNodeInternal(const EditorRawDOMPoint& aPoint,
 
   // unless there isn't one, in which case we are at the end of the node
   // and want the deep-right child.
-  nsIContent* rightMostContent =
-      GetRightmostChild(aPoint.GetContainer(), aNoBlockCrossing);
-  if (!rightMostContent) {
+  nsIContent* lastLeafContent = HTMLEditUtils::GetLastLeafChild(
+      *aPoint.GetContainer(), aNoBlockCrossing ? ChildBlockBoundary::TreatAsLeaf
+                                               : ChildBlockBoundary::Ignore);
+  if (!lastLeafContent) {
     return nullptr;
   }
 
   if ((!aFindEditableNode ||
-       EditorUtils::IsEditableContent(*rightMostContent, GetEditorType())) &&
-      (aFindAnyDataNode || EditorUtils::IsElementOrText(*rightMostContent))) {
-    return rightMostContent;
+       EditorUtils::IsEditableContent(*lastLeafContent, GetEditorType())) &&
+      (aFindAnyDataNode || EditorUtils::IsElementOrText(*lastLeafContent))) {
+    return lastLeafContent;
   }
 
   // restart the search from the non-editable node we just found
-  return GetPreviousNodeInternal(*rightMostContent, aFindEditableNode,
+  return GetPreviousNodeInternal(*lastLeafContent, aFindEditableNode,
                                  aFindAnyDataNode, aNoBlockCrossing);
 }
 
-nsIContent* EditorBase::GetNextNodeInternal(nsINode& aNode,
+nsIContent* EditorBase::GetNextNodeInternal(const nsINode& aNode,
                                             bool aFindEditableNode,
                                             bool aFindAnyDataNode,
                                             bool aNoBlockCrossing) const {
@@ -2909,24 +2911,25 @@ nsIContent* EditorBase::GetNextNodeInternal(const EditorRawDOMPoint& aPoint,
       return point.GetChild();
     }
 
-    nsIContent* leftMostContent =
-        GetLeftmostChild(point.GetChild(), aNoBlockCrossing);
-    if (!leftMostContent) {
+    nsIContent* firstLeafContent = HTMLEditUtils::GetFirstLeafChild(
+        *point.GetChild(), aNoBlockCrossing ? ChildBlockBoundary::TreatAsLeaf
+                                            : ChildBlockBoundary::Ignore);
+    if (!firstLeafContent) {
       return point.GetChild();
     }
 
-    if (!IsDescendantOfEditorRoot(leftMostContent)) {
+    if (!IsDescendantOfEditorRoot(firstLeafContent)) {
       return nullptr;
     }
 
     if ((!aFindEditableNode ||
-         EditorUtils::IsEditableContent(*leftMostContent, GetEditorType())) &&
-        (aFindAnyDataNode || EditorUtils::IsElementOrText(*leftMostContent))) {
-      return leftMostContent;
+         EditorUtils::IsEditableContent(*firstLeafContent, GetEditorType())) &&
+        (aFindAnyDataNode || EditorUtils::IsElementOrText(*firstLeafContent))) {
+      return firstLeafContent;
     }
 
     // restart the search from the non-editable node we just found
-    return GetNextNodeInternal(*leftMostContent, aFindEditableNode,
+    return GetNextNodeInternal(*firstLeafContent, aFindEditableNode,
                                aFindAnyDataNode, aNoBlockCrossing);
   }
 
@@ -2942,14 +2945,15 @@ nsIContent* EditorBase::GetNextNodeInternal(const EditorRawDOMPoint& aPoint,
                              aFindAnyDataNode, aNoBlockCrossing);
 }
 
-nsIContent* EditorBase::FindNextLeafNode(nsINode* aCurrentNode, bool aGoForward,
+nsIContent* EditorBase::FindNextLeafNode(const nsINode* aCurrentNode,
+                                         bool aGoForward,
                                          bool bNoBlockCrossing) const {
   // called only by GetPriorNode so we don't need to check params.
   MOZ_ASSERT(
       IsDescendantOfEditorRoot(aCurrentNode) && !IsEditorRoot(aCurrentNode),
       "Bogus arguments");
 
-  nsINode* cur = aCurrentNode;
+  const nsINode* cur = aCurrentNode;
   for (;;) {
     // if aCurrentNode has a sibling in the right direction, return
     // that sibling's closest child (or itself if it has no children)
@@ -2960,14 +2964,14 @@ nsIContent* EditorBase::FindNextLeafNode(nsINode* aCurrentNode, bool aGoForward,
         // don't look inside prevsib, since it is a block
         return sibling;
       }
-      nsIContent* leaf = aGoForward
-                             ? GetLeftmostChild(sibling, bNoBlockCrossing)
-                             : GetRightmostChild(sibling, bNoBlockCrossing);
-      if (!leaf) {
-        return sibling;
-      }
-
-      return leaf;
+      ChildBlockBoundary childBlockBoundary =
+          bNoBlockCrossing ? ChildBlockBoundary::TreatAsLeaf
+                           : ChildBlockBoundary::Ignore;
+      nsIContent* leafContent =
+          aGoForward
+              ? HTMLEditUtils::GetFirstLeafChild(*sibling, childBlockBoundary)
+              : HTMLEditUtils::GetLastLeafChild(*sibling, childBlockBoundary);
+      return leafContent ? leafContent : sibling;
     }
 
     nsINode* parent = cur->GetParentNode();
@@ -2992,7 +2996,7 @@ nsIContent* EditorBase::FindNextLeafNode(nsINode* aCurrentNode, bool aGoForward,
   return nullptr;
 }
 
-nsIContent* EditorBase::FindNode(nsINode* aCurrentNode, bool aGoForward,
+nsIContent* EditorBase::FindNode(const nsINode* aCurrentNode, bool aGoForward,
                                  bool aEditableNode, bool aFindAnyDataNode,
                                  bool bNoBlockCrossing) const {
   if (IsEditorRoot(aCurrentNode)) {
@@ -3020,55 +3024,7 @@ nsIContent* EditorBase::FindNode(nsINode* aCurrentNode, bool aGoForward,
                   bNoBlockCrossing);
 }
 
-nsIContent* EditorBase::GetRightmostChild(nsINode* aCurrentNode,
-                                          bool bNoBlockCrossing) const {
-  if (NS_WARN_IF(!aCurrentNode)) {
-    return nullptr;
-  }
-  nsIContent* content = aCurrentNode->GetLastChild();
-  if (!content) {
-    return nullptr;
-  }
-  for (;;) {
-    if (bNoBlockCrossing && HTMLEditUtils::IsBlockElement(*content)) {
-      return content;
-    }
-    nsIContent* nextContent = content->GetLastChild();
-    if (!nextContent) {
-      return content;
-    }
-    content = nextContent;
-  }
-
-  MOZ_ASSERT_UNREACHABLE("What part of for(;;) do you not understand?");
-  return nullptr;
-}
-
-nsIContent* EditorBase::GetLeftmostChild(nsINode* aCurrentNode,
-                                         bool bNoBlockCrossing) const {
-  if (NS_WARN_IF(!aCurrentNode)) {
-    return nullptr;
-  }
-  nsIContent* content = aCurrentNode->GetFirstChild();
-  if (!content) {
-    return nullptr;
-  }
-  for (;;) {
-    if (bNoBlockCrossing && HTMLEditUtils::IsBlockElement(*content)) {
-      return content;
-    }
-    nsIContent* next = content->GetFirstChild();
-    if (!next) {
-      return content;
-    }
-    content = next;
-  }
-
-  MOZ_ASSERT_UNREACHABLE("What part of for(;;) do you not understand?");
-  return nullptr;
-}
-
-bool EditorBase::IsRoot(nsINode* inNode) const {
+bool EditorBase::IsRoot(const nsINode* inNode) const {
   if (NS_WARN_IF(!inNode)) {
     return false;
   }
@@ -3076,7 +3032,7 @@ bool EditorBase::IsRoot(nsINode* inNode) const {
   return inNode == rootNode;
 }
 
-bool EditorBase::IsEditorRoot(nsINode* aNode) const {
+bool EditorBase::IsEditorRoot(const nsINode* aNode) const {
   if (NS_WARN_IF(!aNode)) {
     return false;
   }
@@ -3084,7 +3040,7 @@ bool EditorBase::IsEditorRoot(nsINode* aNode) const {
   return aNode == rootNode;
 }
 
-bool EditorBase::IsDescendantOfRoot(nsINode* inNode) const {
+bool EditorBase::IsDescendantOfRoot(const nsINode* inNode) const {
   if (NS_WARN_IF(!inNode)) {
     return false;
   }
@@ -3096,7 +3052,7 @@ bool EditorBase::IsDescendantOfRoot(nsINode* inNode) const {
   return inNode->IsInclusiveDescendantOf(root);
 }
 
-bool EditorBase::IsDescendantOfEditorRoot(nsINode* aNode) const {
+bool EditorBase::IsDescendantOfEditorRoot(const nsINode* aNode) const {
   if (NS_WARN_IF(!aNode)) {
     return false;
   }
@@ -3225,36 +3181,6 @@ nsresult EditorBase::GetEndChildNode(const Selection& aSelection,
   return NS_OK;
 }
 
-/**
- * IsPreformatted() checks the style info for the node for the preformatted
- * text style.
- */
-// static
-bool EditorBase::IsPreformatted(nsINode* aNode) {
-  if (NS_WARN_IF(!aNode)) {
-    return false;
-  }
-  // Look at the node (and its parent if it's not an element), and grab its
-  // ComputedStyle.
-  Element* element = aNode->GetAsElementOrParentElement();
-  if (!element) {
-    return false;
-  }
-
-  RefPtr<ComputedStyle> elementStyle =
-      nsComputedDOMStyle::GetComputedStyleNoFlush(element, nullptr);
-  if (!elementStyle) {
-    // Consider nodes without a ComputedStyle to be NOT preformatted:
-    // For instance, this is true of JS tags inside the body (which show
-    // up as #text nodes but have no ComputedStyle).
-    return false;
-  }
-
-  const nsStyleText* styleText = elementStyle->StyleText();
-
-  return styleText->WhiteSpaceIsSignificant();
-}
-
 nsresult EditorBase::EnsureNoPaddingBRElementForEmptyEditor() {
   MOZ_ASSERT(IsEditActionDataAvailable());
 
@@ -4260,23 +4186,10 @@ nsresult EditorBase::DeleteSelectionWithTransaction(
   return rv;
 }
 
-nsresult EditorBase::CreateRange(nsINode* aStartContainer, int32_t aStartOffset,
-                                 nsINode* aEndContainer, int32_t aEndOffset,
-                                 nsRange** aRange) {
-  RefPtr<nsRange> range = nsRange::Create(
-      aStartContainer, aStartOffset, aEndContainer, aEndOffset, IgnoreErrors());
-  if (!range) {
-    NS_WARNING("nsRange::Create() failed");
-    return NS_ERROR_FAILURE;
-  }
-  range.forget(aRange);
-  return NS_OK;
-}
-
 nsresult EditorBase::AppendNodeToSelectionAsRange(nsINode* aNode) {
   MOZ_ASSERT(IsEditActionDataAvailable());
 
-  if (NS_WARN_IF(!aNode) && NS_WARN_IF(!aNode->IsContent())) {
+  if (NS_WARN_IF(!aNode) || NS_WARN_IF(!aNode->IsContent())) {
     return NS_ERROR_INVALID_ARG;
   }
 
@@ -4285,15 +4198,11 @@ nsresult EditorBase::AppendNodeToSelectionAsRange(nsINode* aNode) {
     return NS_ERROR_FAILURE;
   }
 
-  RefPtr<nsRange> range;
-  nsresult rv = CreateRange(atContent.GetContainer(), atContent.Offset(),
-                            atContent.GetContainer(), atContent.Offset() + 1,
-                            getter_AddRefs(range));
-  if (NS_FAILED(rv)) {
-    NS_WARNING("EditorBase::CreateRange() failed");
-    return rv;
-  }
+  RefPtr<nsRange> range = nsRange::Create(
+      atContent.ToRawRangeBoundary(),
+      atContent.NextPoint().ToRawRangeBoundary(), IgnoreErrors());
   if (NS_WARN_IF(!range)) {
+    NS_WARNING("nsRange::Create() failed");
     return NS_ERROR_FAILURE;
   }
 
diff --git a/editor/libeditor/EditorBase.h b/editor/libeditor/EditorBase.h
index 44af69ac65..8c8caab29e 100644
--- a/editor/libeditor/EditorBase.h
+++ b/editor/libeditor/EditorBase.h
@@ -1601,22 +1601,22 @@ class EditorBase : public nsIEditor,
       const EditorRawDOMPoint& aPoint) const {
     return GetPreviousNodeInternal(aPoint, true, true, true);
   }
-  nsIContent* GetPreviousNode(nsINode& aNode) const {
+  nsIContent* GetPreviousNode(const nsINode& aNode) const {
     return GetPreviousNodeInternal(aNode, false, true, false);
   }
-  nsIContent* GetPreviousElementOrText(nsINode& aNode) const {
+  nsIContent* GetPreviousElementOrText(const nsINode& aNode) const {
     return GetPreviousNodeInternal(aNode, false, false, false);
   }
-  nsIContent* GetPreviousEditableNode(nsINode& aNode) const {
+  nsIContent* GetPreviousEditableNode(const nsINode& aNode) const {
     return GetPreviousNodeInternal(aNode, true, true, false);
   }
-  nsIContent* GetPreviousNodeInBlock(nsINode& aNode) const {
+  nsIContent* GetPreviousNodeInBlock(const nsINode& aNode) const {
     return GetPreviousNodeInternal(aNode, false, true, true);
   }
-  nsIContent* GetPreviousElementOrTextInBlock(nsINode& aNode) const {
+  nsIContent* GetPreviousElementOrTextInBlock(const nsINode& aNode) const {
     return GetPreviousNodeInternal(aNode, false, false, true);
   }
-  nsIContent* GetPreviousEditableNodeInBlock(nsINode& aNode) const {
+  nsIContent* GetPreviousEditableNodeInBlock(const nsINode& aNode) const {
     return GetPreviousNodeInternal(aNode, true, true, true);
   }
 
@@ -1675,50 +1675,36 @@ class EditorBase : public nsIEditor,
       const EditorDOMPointBase<PT, CT>& aPoint) const {
     return GetNextNodeInternal(aPoint, true, true, true);
   }
-  nsIContent* GetNextNode(nsINode& aNode) const {
+  nsIContent* GetNextNode(const nsINode& aNode) const {
     return GetNextNodeInternal(aNode, false, true, false);
   }
-  nsIContent* GetNextElementOrText(nsINode& aNode) const {
+  nsIContent* GetNextElementOrText(const nsINode& aNode) const {
     return GetNextNodeInternal(aNode, false, false, false);
   }
-  nsIContent* GetNextEditableNode(nsINode& aNode) const {
+  nsIContent* GetNextEditableNode(const nsINode& aNode) const {
     return GetNextNodeInternal(aNode, true, true, false);
   }
-  nsIContent* GetNextNodeInBlock(nsINode& aNode) const {
+  nsIContent* GetNextNodeInBlock(const nsINode& aNode) const {
     return GetNextNodeInternal(aNode, false, true, true);
   }
-  nsIContent* GetNextElementOrTextInBlock(nsINode& aNode) const {
+  nsIContent* GetNextElementOrTextInBlock(const nsINode& aNode) const {
     return GetNextNodeInternal(aNode, false, false, true);
   }
-  nsIContent* GetNextEditableNodeInBlock(nsINode& aNode) const {
+  nsIContent* GetNextEditableNodeInBlock(const nsINode& aNode) const {
     return GetNextNodeInternal(aNode, true, true, true);
   }
 
-  /**
-   * Get the rightmost child of aCurrentNode;
-   * return nullptr if aCurrentNode has no children.
-   */
-  nsIContent* GetRightmostChild(nsINode* aCurrentNode,
-                                bool bNoBlockCrossing = false) const;
-
-  /**
-   * Get the leftmost child of aCurrentNode;
-   * return nullptr if aCurrentNode has no children.
-   */
-  nsIContent* GetLeftmostChild(nsINode* aCurrentNode,
-                               bool bNoBlockCrossing = false) const;
-
   /**
    * Returns true if aNode is our root node.
    */
-  bool IsRoot(nsINode* inNode) const;
-  bool IsEditorRoot(nsINode* aNode) const;
+  bool IsRoot(const nsINode* inNode) const;
+  bool IsEditorRoot(const nsINode* aNode) const;
 
   /**
    * Returns true if aNode is a descendant of our root node.
    */
-  bool IsDescendantOfRoot(nsINode* inNode) const;
-  bool IsDescendantOfEditorRoot(nsINode* aNode) const;
+  bool IsDescendantOfRoot(const nsINode* inNode) const;
+  bool IsDescendantOfEditorRoot(const nsINode* aNode) const;
 
   /**
    * Counts number of editable child nodes.
@@ -1757,16 +1743,6 @@ class EditorBase : public nsIEditor,
    */
   nsresult CollapseSelectionToEnd();
 
-  /**
-   * Helpers to add a node to the selection.
-   * Used by table cell selection methods.
-   */
-  nsresult CreateRange(nsINode* aStartContainer, int32_t aStartOffset,
-                       nsINode* aEndContainer, int32_t aEndOffset,
-                       nsRange** aRange);
-
-  static bool IsPreformatted(nsINode* aNode);
-
   /**
    * AllowsTransactionsToChangeSelection() returns true if editor allows any
    * transactions to change Selection.  Otherwise, transactions shouldn't
@@ -2050,9 +2026,9 @@ class EditorBase : public nsIEditor,
   /**
    * Helper for GetPreviousNodeInternal() and GetNextNodeInternal().
    */
-  nsIContent* FindNextLeafNode(nsINode* aCurrentNode, bool aGoForward,
+  nsIContent* FindNextLeafNode(const nsINode* aCurrentNode, bool aGoForward,
                                bool bNoBlockCrossing) const;
-  nsIContent* FindNode(nsINode* aCurrentNode, bool aGoForward,
+  nsIContent* FindNode(const nsINode* aCurrentNode, bool aGoForward,
                        bool aEditableNode, bool aFindAnyDataNode,
                        bool bNoBlockCrossing) const;
 
@@ -2069,7 +2045,8 @@ class EditorBase : public nsIEditor,
    *                             aFindEditableNode is true.  If there is no
    *                             previous node, returns nullptr.
    */
-  nsIContent* GetPreviousNodeInternal(nsINode& aNode, bool aFindEditableNode,
+  nsIContent* GetPreviousNodeInternal(const nsINode& aNode,
+                                      bool aFindEditableNode,
                                       bool aFindAnyDataNode,
                                       bool aNoBlockCrossing) const;
 
@@ -2094,9 +2071,9 @@ class EditorBase : public nsIEditor,
    *                             aFindEditableNode is true.  If there is no
    *                             next node, returns nullptr.
    */
-  nsIContent* GetNextNodeInternal(nsINode& aNode, bool aFindEditableNode,
+  nsIContent* GetNextNodeInternal(const nsINode& aNode, bool aFindEditableNode,
                                   bool aFindAnyDataNode,
-                                  bool bNoBlockCrossing) const;
+                                  bool aNoBlockCrossing) const;
 
   /**
    * And another version that takes a point in DOM tree rather than a node.
diff --git a/editor/libeditor/EditorUtils.cpp b/editor/libeditor/EditorUtils.cpp
index 278e4da50f..509658c7dd 100644
--- a/editor/libeditor/EditorUtils.cpp
+++ b/editor/libeditor/EditorUtils.cpp
@@ -2,22 +2,25 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-#include "mozilla/EditorUtils.h"
+#include "EditorUtils.h"
 
+#include "mozilla/ComputedStyle.h"
 #include "mozilla/ContentIterator.h"
 #include "mozilla/EditorDOMPoint.h"
 #include "mozilla/OwningNonNull.h"
 #include "mozilla/TextEditor.h"
+#include "mozilla/dom/Document.h"
 #include "mozilla/dom/HTMLBRElement.h"
 #include "mozilla/dom/Selection.h"
 #include "mozilla/dom/Text.h"
 #include "nsContentUtils.h"
 #include "nsComponentManagerUtils.h"
+#include "nsComputedDOMStyle.h"
 #include "nsError.h"
 #include "nsIContent.h"
-#include "mozilla/dom/Document.h"
 #include "nsIInterfaceRequestorUtils.h"
 #include "nsINode.h"
+#include "nsStyleStruct.h"
 
 class nsISupports;
 class nsRange;
@@ -229,4 +232,25 @@ void EditorUtils::MaskString(nsString& aString, Text* aText,
   }
 }
 
+// static
+bool EditorUtils::IsContentPreformatted(nsIContent& aContent) {
+  // Look at the node (and its parent if it's not an element), and grab its
+  // ComputedStyle.
+  Element* element = aContent.GetAsElementOrParentElement();
+  if (!element) {
+    return false;
+  }
+
+  RefPtr<ComputedStyle> elementStyle =
+      nsComputedDOMStyle::GetComputedStyleNoFlush(element, nullptr);
+  if (!elementStyle) {
+    // Consider nodes without a ComputedStyle to be NOT preformatted:
+    // For instance, this is true of JS tags inside the body (which show
+    // up as #text nodes but have no ComputedStyle).
+    return false;
+  }
+
+  return elementStyle->StyleText()->WhiteSpaceIsSignificant();
+}
+
 }  // namespace mozilla
diff --git a/editor/libeditor/EditorUtils.h b/editor/libeditor/EditorUtils.h
index c4eadc4710..a23d34f416 100644
--- a/editor/libeditor/EditorUtils.h
+++ b/editor/libeditor/EditorUtils.h
@@ -854,6 +854,12 @@ class EditorUtils final {
            !EditorUtils::IsPaddingBRElementForEmptyEditor(aContent);
   }
 
+  /**
+   * IsContentPreformatted() checks the style info for the node for the
+   * preformatted text style.  This does NOT flush layout.
+   */
+  static bool IsContentPreformatted(nsIContent& aContent);
+
   /**
    * Helper method for `AppendString()` and `AppendSubString()`.  This should
    * be called only when `aText` is in a password field.  This method masks
diff --git a/editor/libeditor/HTMLAbsPositionEditor.cpp b/editor/libeditor/HTMLAbsPositionEditor.cpp
index e407d9abdc..99df8d7a41 100644
--- a/editor/libeditor/HTMLAbsPositionEditor.cpp
+++ b/editor/libeditor/HTMLAbsPositionEditor.cpp
@@ -80,7 +80,7 @@ HTMLEditor::GetAbsolutelyPositionedSelectionContainer() const {
 
   AutoTArray<RefPtr<Element>, 24> arrayOfParentElements;
   for (Element* element :
-       InclusiveAncestorsOfType<Element>(*selectionContainerElement)) {
+       selectionContainerElement->InclusiveAncestorsOfType<Element>()) {
     arrayOfParentElements.AppendElement(element);
   }
 
diff --git a/editor/libeditor/HTMLEditSubActionHandler.cpp b/editor/libeditor/HTMLEditSubActionHandler.cpp
index 81b3b3dea6..37f18f2353 100644
--- a/editor/libeditor/HTMLEditSubActionHandler.cpp
+++ b/editor/libeditor/HTMLEditSubActionHandler.cpp
@@ -67,6 +67,7 @@ namespace mozilla {
 
 using namespace dom;
 using StyleDifference = HTMLEditUtils::StyleDifference;
+using ChildBlockBoundary = HTMLEditUtils::ChildBlockBoundary;
 
 enum { kLonely = 0, kPrevSib = 1, kNextSib = 2, kBothSibs = 3 };
 
@@ -97,14 +98,11 @@ static bool IsStyleCachePreservingSubAction(EditSubAction aEditSubAction) {
 }
 
 class MOZ_RAII AutoSetTemporaryAncestorLimiter final {
-  MOZ_DECL_USE_GUARD_OBJECT_NOTIFIER;
 
  public:
-  explicit AutoSetTemporaryAncestorLimiter(
-      HTMLEditor& aHTMLEditor, Selection& aSelection,
-      nsINode& aStartPointNode MOZ_GUARD_OBJECT_NOTIFIER_PARAM) {
-    MOZ_GUARD_OBJECT_NOTIFIER_INIT;
-
+  explicit AutoSetTemporaryAncestorLimiter(HTMLEditor& aHTMLEditor,
+                                           Selection& aSelection,
+                                           nsINode& aStartPointNode) {
     MOZ_ASSERT(aSelection.GetType() == SelectionType::eNormal);
 
     if (aSelection.GetAncestorLimiter()) {
@@ -1009,7 +1007,7 @@ AlignStateAtSelection::AlignStateAtSelection(HTMLEditor& aHTMLEditor,
   }
 
   for (nsIContent* containerContent :
-       InclusiveAncestorsOfType<nsIContent>(*editTargetContent)) {
+       editTargetContent->InclusiveAncestorsOfType<nsIContent>()) {
     // If the node is a parent `<table>` element of edit target, let's break
     // here to materialize the 'inline-block' behaviour of html tables
     // regarding to text alignment.
@@ -1453,7 +1451,8 @@ EditActionResult HTMLEditor::HandleInsertText(
   }
 
   EditorDOMPoint pointToInsert(firstRange->StartRef());
-  if (NS_WARN_IF(!pointToInsert.IsSet())) {
+  if (NS_WARN_IF(!pointToInsert.IsSet()) ||
+      NS_WARN_IF(!pointToInsert.IsInContentNode())) {
     return EditActionHandled(NS_ERROR_FAILURE);
   }
   MOZ_ASSERT(pointToInsert.IsSetAndValid());
@@ -1521,7 +1520,8 @@ EditActionResult HTMLEditor::HandleInsertText(
 
   // is our text going to be PREformatted?
   // We remember this so that we know how to handle tabs.
-  bool isPRE = EditorBase::IsPreformatted(pointToInsert.GetContainer());
+  bool isPRE =
+      EditorUtils::IsContentPreformatted(*pointToInsert.ContainerAsContent());
 
   // turn off the edit listener: we know how to
   // build the "doc changed range" ourselves, and it's
@@ -7825,8 +7825,9 @@ nsresult HTMLEditor::MaybeExtendSelectionToHardLineEdgesForBlockEditAction() {
     // of going "down" into a block and "up" out of a block.
     if (wsScannerAtEnd.StartsFromOtherBlockElement()) {
       // endpoint is just after the close of a block.
-      nsINode* child = GetRightmostChild(
-          wsScannerAtEnd.StartReasonOtherBlockElementPtr(), true);
+      nsIContent* child = HTMLEditUtils::GetLastLeafChild(
+          *wsScannerAtEnd.StartReasonOtherBlockElementPtr(),
+          ChildBlockBoundary::TreatAsLeaf);
       if (child) {
         newEndPoint.SetAfter(child);
       }
@@ -7853,8 +7854,9 @@ nsresult HTMLEditor::MaybeExtendSelectionToHardLineEdgesForBlockEditAction() {
     // of going "down" into a block and "up" out of a block.
     if (wsScannerAtStart.EndsByOtherBlockElement()) {
       // startpoint is just before the start of a block.
-      nsINode* child = GetLeftmostChild(
-          wsScannerAtStart.EndReasonOtherBlockElementPtr(), true);
+      nsINode* child = HTMLEditUtils::GetFirstLeafChild(
+          *wsScannerAtStart.EndReasonOtherBlockElementPtr(),
+          ChildBlockBoundary::TreatAsLeaf);
       if (child) {
         newStartPoint.Set(child);
       }
@@ -8072,8 +8074,8 @@ EditorDOMPoint HTMLEditor::GetCurrentHardLineEndPoint(
     }
 
     // Check for newlines in pre-formatted text nodes.
-    if (EditorBase::IsPreformatted(nextEditableContent) &&
-        nextEditableContent->IsText()) {
+    if (nextEditableContent->IsText() &&
+        EditorUtils::IsContentPreformatted(*nextEditableContent)) {
       nsAutoString textContent;
       nextEditableContent->GetAsText()->GetData(textContent);
       int32_t newlinePos = textContent.FindChar(nsCRT::LF);
@@ -8793,8 +8795,7 @@ nsIContent* HTMLEditor::GetMostAncestorInlineElement(nsINode& aNode) const {
 
   // Looks for the highest inline parent in the editing host.
   nsIContent* topMostInlineContent = aNode.AsContent();
-  for (nsIContent* content :
-       InclusiveAncestorsOfType<nsIContent>(*aNode.GetParent())) {
+  for (nsIContent* content : aNode.AncestorsOfType<nsIContent>()) {
     if (content == host || !HTMLEditUtils::IsInlineElement(*content)) {
       break;
     }
@@ -9237,7 +9238,8 @@ nsresult HTMLEditor::SplitParagraph(
 
   // selection to beginning of right hand para;
   // look inside any containers that are up front.
-  nsCOMPtr<nsIContent> child = GetLeftmostChild(&aParentDivOrP, true);
+  nsCOMPtr<nsIContent> child = HTMLEditUtils::GetFirstLeafChild(
+      aParentDivOrP, ChildBlockBoundary::TreatAsLeaf);
   if (child && (child->IsText() || HTMLEditUtils::IsContainerNode(*child))) {
     nsresult rv = CollapseSelectionToStartOf(*child);
     if (NS_WARN_IF(rv == NS_ERROR_EDITOR_DESTROYED)) {
diff --git a/editor/libeditor/HTMLEditUtils.h b/editor/libeditor/HTMLEditUtils.h
index b6ae52cafa..fd19902adf 100644
--- a/editor/libeditor/HTMLEditUtils.h
+++ b/editor/libeditor/HTMLEditUtils.h
@@ -193,6 +193,280 @@ class HTMLEditUtils final {
   static bool IsNonListSingleLineContainer(nsINode& aNode);
   static bool IsSingleLineContainer(nsINode& aNode);
 
+  /**
+   * GetLastLeafChild() returns rightmost leaf content in aNode.  It depends on
+   * aChildBlockBoundary whether this scans into a block child or treat
+   * block as a leaf.
+   */
+  enum class ChildBlockBoundary {
+    // Even if there is a child block, keep scanning a leaf content in it.
+    Ignore,
+    // If there is a child block, return it.
+    TreatAsLeaf,
+  };
+  static nsIContent* GetLastLeafChild(nsINode& aNode,
+                                      ChildBlockBoundary aChildBlockBoundary) {
+    for (nsIContent* content = aNode.GetLastChild(); content;
+         content = content->GetLastChild()) {
+      if (aChildBlockBoundary == ChildBlockBoundary::TreatAsLeaf &&
+          HTMLEditUtils::IsBlockElement(*content)) {
+        return content;
+      }
+      if (!content->HasChildren()) {
+        return content;
+      }
+    }
+    return nullptr;
+  }
+
+  /**
+   * GetFirstLeafChild() returns leftmost leaf content in aNode.  It depends on
+   * aChildBlockBoundary whether this scans into a block child or treat
+   * block as a leaf.
+   */
+  static nsIContent* GetFirstLeafChild(nsINode& aNode,
+                                       ChildBlockBoundary aChildBlockBoundary) {
+    for (nsIContent* content = aNode.GetFirstChild(); content;
+         content = content->GetFirstChild()) {
+      if (aChildBlockBoundary == ChildBlockBoundary::TreatAsLeaf &&
+          HTMLEditUtils::IsBlockElement(*content)) {
+        return content;
+      }
+      if (!content->HasChildren()) {
+        return content;
+      }
+    }
+    return nullptr;
+  }
+
+  /**
+   * GetNextLeafContentOrNextBlockElement() returns next leaf content or
+   * next block element of aStartContent inside aAncestorLimiter.
+   * Note that the result may be a contet outside aCurrentBlock if
+   * aStartContent equals aCurrentBlock.
+   *
+   * @param aStartContent       The start content to scan next content.
+   * @param aCurrentBlock       Must be ancestor of aStartContent.  Dispite
+   *                            the name, inline content is allowed if
+   *                            aStartContent is in an inline editing host.
+   * @param aAncestorLimiter    Optional, setting this guarantees the
+   *                            result is in aAncestorLimiter unless
+   *                            aStartContent is not a descendant of this.
+   */
+  static nsIContent* GetNextLeafContentOrNextBlockElement(
+      nsIContent& aStartContent, nsIContent& aCurrentBlock,
+      Element* aAncestorLimiter = nullptr) {
+    if (&aStartContent == aAncestorLimiter) {
+      return nullptr;
+    }
+
+    nsIContent* nextContent = aStartContent.GetNextSibling();
+    if (!nextContent) {
+      if (!aStartContent.GetParentElement()) {
+        NS_WARNING("Reached orphan node while climbing up the DOM tree");
+        return nullptr;
+      }
+      for (Element* parentElement : aStartContent.AncestorsOfType<Element>()) {
+        if (parentElement == &aCurrentBlock) {
+          return nullptr;
+        }
+        if (parentElement == aAncestorLimiter) {
+          NS_WARNING("Reached editing host while climbing up the DOM tree");
+          return nullptr;
+        }
+        nextContent = parentElement->GetNextSibling();
+        if (nextContent) {
+          break;
+        }
+        if (!parentElement->GetParentElement()) {
+          NS_WARNING("Reached orphan node while climbing up the DOM tree");
+          return nullptr;
+        }
+      }
+      MOZ_ASSERT(nextContent);
+    }
+
+    // We have a next content.  If it's a block, return it.
+    if (HTMLEditUtils::IsBlockElement(*nextContent)) {
+      return nextContent;
+    }
+    if (HTMLEditUtils::IsContainerNode(*nextContent)) {
+      // Else if it's a container, get deep leftmost child
+      if (nsIContent* child = HTMLEditUtils::GetFirstLeafChild(
+              *nextContent, ChildBlockBoundary::Ignore)) {
+        return child;
+      }
+    }
+    // Else return the next content itself.
+    return nextContent;
+  }
+
+  /**
+   * Similar to the above method, but take a DOM point to specify scan start
+   * point.
+   */
+  template <typename PT, typename CT>
+  static nsIContent* GetNextLeafContentOrNextBlockElement(
+      const EditorDOMPointBase<PT, CT>& aStartPoint, nsIContent& aCurrentBlock,
+      Element* aAncestorLimiter = nullptr) {
+    MOZ_ASSERT(aStartPoint.IsSet());
+
+    if (!aStartPoint.IsInContentNode()) {
+      return nullptr;
+    }
+    if (aStartPoint.IsInTextNode()) {
+      return HTMLEditUtils::GetNextLeafContentOrNextBlockElement(
+          *aStartPoint.ContainerAsText(), aCurrentBlock, aAncestorLimiter);
+    }
+    if (!HTMLEditUtils::IsContainerNode(*aStartPoint.ContainerAsContent())) {
+      return HTMLEditUtils::GetNextLeafContentOrNextBlockElement(
+          *aStartPoint.ContainerAsContent(), aCurrentBlock, aAncestorLimiter);
+    }
+
+    nsCOMPtr<nsIContent> nextContent = aStartPoint.GetChild();
+    if (!nextContent) {
+      if (aStartPoint.GetContainer() == &aCurrentBlock) {
+        // We are at end of the block.
+        return nullptr;
+      }
+
+      // We are at end of non-block container
+      return HTMLEditUtils::GetNextLeafContentOrNextBlockElement(
+          *aStartPoint.ContainerAsContent(), aCurrentBlock, aAncestorLimiter);
+    }
+
+    // We have a next node.  If it's a block, return it.
+    if (HTMLEditUtils::IsBlockElement(*nextContent)) {
+      return nextContent;
+    }
+    if (HTMLEditUtils::IsContainerNode(*nextContent)) {
+      // else if it's a container, get deep leftmost child
+      if (nsIContent* child = HTMLEditUtils::GetFirstLeafChild(
+              *nextContent, ChildBlockBoundary::Ignore)) {
+        return child;
+      }
+    }
+    // Else return the node itself
+    return nextContent;
+  }
+
+  /**
+   * GetPreviousLeafContentOrPreviousBlockElement() returns previous leaf
+   * content or previous block element of aStartContent inside
+   * aAncestorLimiter.
+   * Note that the result may be a contet outside aCurrentBlock if
+   * aStartContent equals aCurrentBlock.
+   *
+   * @param aStartContent       The start content to scan previous content.
+   * @param aCurrentBlock       Must be ancestor of aStartContent.  Dispite
+   *                            the name, inline content is allowed if
+   *                            aStartContent is in an inline editing host.
+   * @param aAncestorLimiter    Optional, setting this guarantees the
+   *                            result is in aAncestorLimiter unless
+   *                            aStartContent is not a descendant of this.
+   */
+  static nsIContent* GetPreviousLeafContentOrPreviousBlockElement(
+      nsIContent& aStartContent, nsIContent& aCurrentBlock,
+      Element* aAncestorLimiter = nullptr) {
+    if (&aStartContent == aAncestorLimiter) {
+      return nullptr;
+    }
+
+    nsIContent* previousContent = aStartContent.GetPreviousSibling();
+    if (!previousContent) {
+      if (!aStartContent.GetParentElement()) {
+        NS_WARNING("Reached orphan node while climbing up the DOM tree");
+        return nullptr;
+      }
+      for (Element* parentElement : aStartContent.AncestorsOfType<Element>()) {
+        if (parentElement == &aCurrentBlock) {
+          return nullptr;
+        }
+        if (parentElement == aAncestorLimiter) {
+          NS_WARNING("Reached editing host while climbing up the DOM tree");
+          return nullptr;
+        }
+        previousContent = parentElement->GetPreviousSibling();
+        if (previousContent) {
+          break;
+        }
+        if (!parentElement->GetParentElement()) {
+          NS_WARNING("Reached orphan node while climbing up the DOM tree");
+          return nullptr;
+        }
+      }
+      MOZ_ASSERT(previousContent);
+    }
+
+    // We have a next content.  If it's a block, return it.
+    if (HTMLEditUtils::IsBlockElement(*previousContent)) {
+      return previousContent;
+    }
+    if (HTMLEditUtils::IsContainerNode(*previousContent)) {
+      // Else if it's a container, get deep rightmost child
+      if (nsIContent* child = HTMLEditUtils::GetLastLeafChild(
+              *previousContent, ChildBlockBoundary::Ignore)) {
+        return child;
+      }
+    }
+    // Else return the next content itself.
+    return previousContent;
+  }
+
+  /**
+   * Similar to the above method, but take a DOM point to specify scan start
+   * point.
+   */
+  template <typename PT, typename CT>
+  static nsIContent* GetPreviousLeafContentOrPreviousBlockElement(
+      const EditorDOMPointBase<PT, CT>& aStartPoint, nsIContent& aCurrentBlock,
+      Element* aAncestorLimiter = nullptr) {
+    MOZ_ASSERT(aStartPoint.IsSet());
+
+    if (!aStartPoint.IsInContentNode()) {
+      return nullptr;
+    }
+    if (aStartPoint.IsInTextNode()) {
+      return HTMLEditUtils::GetPreviousLeafContentOrPreviousBlockElement(
+          *aStartPoint.ContainerAsText(), aCurrentBlock, aAncestorLimiter);
+    }
+    if (!HTMLEditUtils::IsContainerNode(*aStartPoint.ContainerAsContent())) {
+      return HTMLEditUtils::GetPreviousLeafContentOrPreviousBlockElement(
+          *aStartPoint.ContainerAsContent(), aCurrentBlock, aAncestorLimiter);
+    }
+
+    if (aStartPoint.IsStartOfContainer()) {
+      if (aStartPoint.GetContainer() == &aCurrentBlock) {
+        // We are at start of the block.
+        return nullptr;
+      }
+
+      // We are at start of non-block container
+      return HTMLEditUtils::GetPreviousLeafContentOrPreviousBlockElement(
+          *aStartPoint.ContainerAsContent(), aCurrentBlock, aAncestorLimiter);
+    }
+
+    nsCOMPtr<nsIContent> previousContent =
+        aStartPoint.GetPreviousSiblingOfChild();
+    if (NS_WARN_IF(!previousContent)) {
+      return nullptr;
+    }
+
+    // We have a prior node.  If it's a block, return it.
+    if (HTMLEditUtils::IsBlockElement(*previousContent)) {
+      return previousContent;
+    }
+    if (HTMLEditUtils::IsContainerNode(*previousContent)) {
+      // Else if it's a container, get deep rightmost child
+      if (nsIContent* child = HTMLEditUtils::GetLastLeafChild(
+              *previousContent, ChildBlockBoundary::Ignore)) {
+        return child;
+      }
+    }
+    // Else return the node itself
+    return previousContent;
+  }
+
   /**
    * GetAncestorBlockElement() returns parent or nearest ancestor of aContent
    * which is a block element.  If aAncestorLimiter is not nullptr,
@@ -209,12 +483,7 @@ class HTMLEditUtils final {
       return nullptr;
     }
 
-    if (!aContent.GetParent()) {
-      return nullptr;
-    }
-
-    for (Element* element : dom::InclusiveAncestorsOfType<Element>(
-             const_cast<nsIContent&>(*aContent.GetParent()))) {
+    for (Element* element : aContent.AncestorsOfType<Element>()) {
       if (HTMLEditUtils::IsBlockElement(*element)) {
         return element;
       }
@@ -257,8 +526,7 @@ class HTMLEditUtils final {
     if (!aContent.GetParent()) {
       return nullptr;
     }
-    for (Element* element : dom::InclusiveAncestorsOfType<Element>(
-             const_cast<nsIContent&>(aContent))) {
+    for (Element* element : aContent.InclusiveAncestorsOfType<Element>()) {
       if (HTMLEditUtils::IsTable(element)) {
         return element;
       }
diff --git a/editor/libeditor/HTMLEditor.cpp b/editor/libeditor/HTMLEditor.cpp
index 932e70311f..e96a02097b 100644
--- a/editor/libeditor/HTMLEditor.cpp
+++ b/editor/libeditor/HTMLEditor.cpp
@@ -63,6 +63,8 @@ namespace mozilla {
 using namespace dom;
 using namespace widget;
 
+using ChildBlockBoundary = HTMLEditUtils::ChildBlockBoundary;
+
 const char16_t kNBSP = 160;
 
 // Some utilities to handle overloading of "A" tag for link and named anchor.
@@ -855,7 +857,7 @@ void HTMLEditor::IsPrevCharInNodeWhitespace(nsIContent* aContent,
   }
 }
 
-bool HTMLEditor::IsVisibleBRElement(nsINode* aNode) {
+bool HTMLEditor::IsVisibleBRElement(const nsINode* aNode) {
   MOZ_ASSERT(aNode);
   if (!aNode->IsHTMLElement(nsGkAtoms::br)) {
     return false;
@@ -2519,7 +2521,7 @@ Element* HTMLEditor::GetInclusiveAncestorByTagNameInternal(
 
   bool lookForLink = IsLinkTag(aTagName);
   bool lookForNamedAnchor = IsNamedAnchorTag(aTagName);
-  for (Element* element : InclusiveAncestorsOfType<Element>(*currentElement)) {
+  for (Element* element : currentElement->InclusiveAncestorsOfType<Element>()) {
     // Stop searching if parent is a body element.  Note: Originally used
     // IsRoot() to/ stop at table cells, but that's too messy when you are
     // trying to find the parent table.
@@ -2739,9 +2741,21 @@ already_AddRefed<Element> HTMLEditor::GetSelectedElement(const nsAtom* aTagName,
     // - <p><b>[def</b>}<br></p>
     // Note that we don't need special handling for <a href> because double
     // clicking it selects the element and we use the first path to handle it.
-    if (lastElementInRange->GetNextSibling() &&
-        lastElementInRange->GetNextSibling()->IsHTMLElement(nsGkAtoms::br)) {
-      return nullptr;
+    // Additionally, we have this case too:
+    // - <p><b>[def</b><b>}<br></b></p>
+    // In these cases, the <br> element is not listed up by PostContentIterator.
+    // So, we should return nullptr if next sibling is a `<br>` element or
+    // next sibling starts with `<br>` element.
+    if (nsIContent* nextSibling = lastElementInRange->GetNextSibling()) {
+      if (nextSibling->IsHTMLElement(nsGkAtoms::br)) {
+        return nullptr;
+      }
+      nsIContent* firstEditableLeaf = HTMLEditUtils::GetFirstLeafChild(
+          *nextSibling, ChildBlockBoundary::Ignore);
+      if (firstEditableLeaf &&
+          firstEditableLeaf->IsHTMLElement(nsGkAtoms::br)) {
+        return nullptr;
+      }
     }
 
     if (!aTagName) {
@@ -3057,8 +3071,7 @@ nsresult HTMLEditor::RemoveEmptyInclusiveAncestorInlineElements(
   }
 
   OwningNonNull<nsIContent> content = aContent;
-  for (nsIContent* parentContent :
-       InclusiveAncestorsOfType<nsIContent>(*aContent.GetParent())) {
+  for (nsIContent* parentContent : aContent.AncestorsOfType<nsIContent>()) {
     if (HTMLEditUtils::IsBlockElement(*parentContent) ||
         parentContent->Length() != 1 ||
         !HTMLEditUtils::IsSimplyEditableNode(*parentContent) ||
@@ -4836,7 +4849,7 @@ nsIContent* HTMLEditor::GetNextHTMLSibling(nsINode* aNode,
 }
 
 nsIContent* HTMLEditor::GetPreviousHTMLElementOrTextInternal(
-    nsINode& aNode, bool aNoBlockCrossing) const {
+    const nsINode& aNode, bool aNoBlockCrossing) const {
   if (NS_WARN_IF(!GetActiveEditingHost())) {
     return nullptr;
   }
@@ -4874,7 +4887,7 @@ nsIContent* HTMLEditor::GetPreviousEditableHTMLNodeInternal(
 }
 
 nsIContent* HTMLEditor::GetNextHTMLElementOrTextInternal(
-    nsINode& aNode, bool aNoBlockCrossing) const {
+    const nsINode& aNode, bool aNoBlockCrossing) const {
   if (NS_WARN_IF(!GetActiveEditingHost())) {
     return nullptr;
   }
@@ -4948,7 +4961,8 @@ nsIContent* HTMLEditor::GetLastEditableChild(nsINode& aNode) const {
 }
 
 nsIContent* HTMLEditor::GetFirstEditableLeaf(nsINode& aNode) const {
-  nsIContent* child = GetLeftmostChild(&aNode);
+  nsIContent* child =
+      HTMLEditUtils::GetFirstLeafChild(aNode, ChildBlockBoundary::Ignore);
   while (child && (!EditorUtils::IsEditableContent(*child, EditorType::HTML) ||
                    child->HasChildren())) {
     child = GetNextEditableHTMLNode(*child);
@@ -4963,7 +4977,8 @@ nsIContent* HTMLEditor::GetFirstEditableLeaf(nsINode& aNode) const {
 }
 
 nsIContent* HTMLEditor::GetLastEditableLeaf(nsINode& aNode) const {
-  nsCOMPtr<nsIContent> child = GetRightmostChild(&aNode, false);
+  nsIContent* child =
+      HTMLEditUtils::GetLastLeafChild(aNode, ChildBlockBoundary::Ignore);
   while (child && (!EditorUtils::IsEditableContent(*child, EditorType::HTML) ||
                    child->HasChildren())) {
     child = GetPreviousEditableHTMLNode(*child);
diff --git a/editor/libeditor/HTMLEditor.h b/editor/libeditor/HTMLEditor.h
index a2655ef5b7..1774ab6e8a 100644
--- a/editor/libeditor/HTMLEditor.h
+++ b/editor/libeditor/HTMLEditor.h
@@ -919,7 +919,7 @@ class HTMLEditor final : public TextEditor,
   /**
    * Small utility routine to test if a break node is visible to user.
    */
-  bool IsVisibleBRElement(nsINode* aNode);
+  bool IsVisibleBRElement(const nsINode* aNode);
 
   /**
    * Helper routines for font size changing.
@@ -999,10 +999,10 @@ class HTMLEditor final : public TextEditor,
    * EditorBase::GetPreviousElementOrText*() but this won't return nodes
    * outside active editing host.
    */
-  nsIContent* GetPreviousHTMLElementOrText(nsINode& aNode) const {
+  nsIContent* GetPreviousHTMLElementOrText(const nsINode& aNode) const {
     return GetPreviousHTMLElementOrTextInternal(aNode, false);
   }
-  nsIContent* GetPreviousHTMLElementOrTextInBlock(nsINode& aNode) const {
+  nsIContent* GetPreviousHTMLElementOrTextInBlock(const nsINode& aNode) const {
     return GetPreviousHTMLElementOrTextInternal(aNode, true);
   }
   template <typename PT, typename CT>
@@ -1020,7 +1020,7 @@ class HTMLEditor final : public TextEditor,
    * GetPreviousHTMLElementOrTextInternal() methods are common implementation
    * of above methods.  Please don't use this method directly.
    */
-  nsIContent* GetPreviousHTMLElementOrTextInternal(nsINode& aNode,
+  nsIContent* GetPreviousHTMLElementOrTextInternal(const nsINode& aNode,
                                                    bool aNoBlockCrossing) const;
   template <typename PT, typename CT>
   nsIContent* GetPreviousHTMLElementOrTextInternal(
@@ -1068,10 +1068,10 @@ class HTMLEditor final : public TextEditor,
    * On the other hand, methods which take |nsINode&| start to search from
    * next node of aNode.
    */
-  nsIContent* GetNextHTMLElementOrText(nsINode& aNode) const {
+  nsIContent* GetNextHTMLElementOrText(const nsINode& aNode) const {
     return GetNextHTMLElementOrTextInternal(aNode, false);
   }
-  nsIContent* GetNextHTMLElementOrTextInBlock(nsINode& aNode) const {
+  nsIContent* GetNextHTMLElementOrTextInBlock(const nsINode& aNode) const {
     return GetNextHTMLElementOrTextInternal(aNode, true);
   }
   template <typename PT, typename CT>
@@ -1089,7 +1089,7 @@ class HTMLEditor final : public TextEditor,
    * GetNextHTMLNodeInternal() methods are common implementation
    * of above methods.  Please don't use this method directly.
    */
-  nsIContent* GetNextHTMLElementOrTextInternal(nsINode& aNode,
+  nsIContent* GetNextHTMLElementOrTextInternal(const nsINode& aNode,
                                                bool aNoBlockCrossing) const;
   template <typename PT, typename CT>
   nsIContent* GetNextHTMLElementOrTextInternal(
diff --git a/editor/libeditor/HTMLStyleEditor.cpp b/editor/libeditor/HTMLStyleEditor.cpp
index 6900ea9fdc..02087e22ec 100644
--- a/editor/libeditor/HTMLStyleEditor.cpp
+++ b/editor/libeditor/HTMLStyleEditor.cpp
@@ -45,6 +45,8 @@ namespace mozilla {
 
 using namespace dom;
 
+using ChildBlockBoundary = HTMLEditUtils::ChildBlockBoundary;
+
 nsresult HTMLEditor::SetInlinePropertyAsAction(nsAtom& aProperty,
                                                nsAtom* aAttribute,
                                                const nsAString& aValue,
@@ -757,7 +759,7 @@ SplitNodeResult HTMLEditor::SplitAncestorStyledInlineElementsAt(
 
   AutoTArray<OwningNonNull<nsIContent>, 24> arrayOfParents;
   for (nsIContent* content :
-       InclusiveAncestorsOfType<nsIContent>(*aPointToSplit.GetContainer())) {
+       aPointToSplit.GetContainer()->InclusiveAncestorsOfType<nsIContent>()) {
     if (HTMLEditUtils::IsBlockElement(*content) || !content->GetParent() ||
         !EditorUtils::IsEditableContent(*content->GetParent(),
                                         EditorType::HTML)) {
@@ -882,10 +884,10 @@ EditResult HTMLEditor::ClearStyleAt(const EditorDOMPoint& aPoint,
   // the next node.  The first example should become
   // `<p><b><i>a</i></b><b><i></i></b><b><i>bc</i></b></p>`.
   //                    ^^^^^^^^^^^^^^
-  nsIContent* leftmostChildOfNextNode =
-      GetLeftmostChild(splitResult.GetNextNode());
-  EditorDOMPoint atStartOfNextNode(leftmostChildOfNextNode
-                                       ? leftmostChildOfNextNode
+  nsIContent* firstLeafChildOfNextNode = HTMLEditUtils::GetFirstLeafChild(
+      *splitResult.GetNextNode(), ChildBlockBoundary::Ignore);
+  EditorDOMPoint atStartOfNextNode(firstLeafChildOfNextNode
+                                       ? firstLeafChildOfNextNode
                                        : splitResult.GetNextNode(),
                                    0);
   RefPtr<HTMLBRElement> brElement;
@@ -940,11 +942,13 @@ EditResult HTMLEditor::ClearStyleAt(const EditorDOMPoint& aPoint,
   // Now, we want to put `<br>` element into the empty split node if
   // it was in next node of the first split.
   // E.g., `<p><b><i>a</i></b><b><i><br></i></b><b><i>bc</i></b></p>`
-  nsIContent* leftmostChild =
-      GetLeftmostChild(splitResultAtStartOfNextNode.GetPreviousNode());
+  nsIContent* firstLeafChildOfPreviousNode = HTMLEditUtils::GetFirstLeafChild(
+      *splitResultAtStartOfNextNode.GetPreviousNode(),
+      ChildBlockBoundary::Ignore);
   EditorDOMPoint pointToPutCaret(
-      leftmostChild ? leftmostChild
-                    : splitResultAtStartOfNextNode.GetPreviousNode(),
+      firstLeafChildOfPreviousNode
+          ? firstLeafChildOfPreviousNode
+          : splitResultAtStartOfNextNode.GetPreviousNode(),
       0);
   // If the right node starts with a `<br>`, suck it out of right node and into
   // the left node left node.  This is so we you don't revert back to the
@@ -1184,7 +1188,7 @@ nsresult HTMLEditor::PromoteRangeIfStartsOrEndsInNamedAnchor(nsRange& aRange) {
   }
   EditorRawDOMPoint newRangeStart(aRange.StartRef());
   for (Element* element :
-       InclusiveAncestorsOfType<Element>(*aRange.GetStartContainer())) {
+       aRange.GetStartContainer()->InclusiveAncestorsOfType<Element>()) {
     if (element->IsHTMLElement(nsGkAtoms::body)) {
       break;
     }
@@ -1204,7 +1208,7 @@ nsresult HTMLEditor::PromoteRangeIfStartsOrEndsInNamedAnchor(nsRange& aRange) {
 
   EditorRawDOMPoint newRangeEnd(aRange.EndRef());
   for (Element* element :
-       InclusiveAncestorsOfType<Element>(*aRange.GetEndContainer())) {
+       aRange.GetEndContainer()->InclusiveAncestorsOfType<Element>()) {
     if (element->IsHTMLElement(nsGkAtoms::body)) {
       break;
     }
@@ -1239,7 +1243,7 @@ nsresult HTMLEditor::PromoteInlineRange(nsRange& aRange) {
   }
   EditorRawDOMPoint newRangeStart(aRange.StartRef());
   for (nsIContent* content :
-       InclusiveAncestorsOfType<nsIContent>(*aRange.GetStartContainer())) {
+       aRange.GetStartContainer()->InclusiveAncestorsOfType<nsIContent>()) {
     MOZ_ASSERT(newRangeStart.GetContainer() == content);
     if (content->IsHTMLElement(nsGkAtoms::body) ||
         !EditorUtils::IsEditableContent(*content, EditorType::HTML) ||
@@ -1257,7 +1261,7 @@ nsresult HTMLEditor::PromoteInlineRange(nsRange& aRange) {
 
   EditorRawDOMPoint newRangeEnd(aRange.EndRef());
   for (nsIContent* content :
-       InclusiveAncestorsOfType<nsIContent>(*aRange.GetEndContainer())) {
+       aRange.GetEndContainer()->InclusiveAncestorsOfType<nsIContent>()) {
     MOZ_ASSERT(newRangeEnd.GetContainer() == content);
     if (content->IsHTMLElement(nsGkAtoms::body) ||
         !EditorUtils::IsEditableContent(*content, EditorType::HTML) ||
diff --git a/editor/libeditor/TextEditor.cpp b/editor/libeditor/TextEditor.cpp
index b6e4945069..59dd254a04 100644
--- a/editor/libeditor/TextEditor.cpp
+++ b/editor/libeditor/TextEditor.cpp
@@ -7,6 +7,7 @@
 #include <algorithm>
 
 #include "EditAggregateTransaction.h"
+#include "HTMLEditUtils.h"
 #include "InternetCiter.h"
 #include "PlaceholderTransaction.h"
 #include "gfxFontUtils.h"
@@ -68,6 +69,8 @@ namespace mozilla {
 
 using namespace dom;
 
+using ChildBlockBoundary = HTMLEditUtils::ChildBlockBoundary;
+
 TextEditor::TextEditor()
     : mMaxTextLength(-1),
       mUnmaskedStart(UINT32_MAX),
@@ -1004,11 +1007,12 @@ nsresult TextEditor::UndoAsAction(uint32_t aCount, nsIPrincipal* aPrincipal) {
       // at redo, or doing it everywhere else that might care.  Since undo
       // and redo are relatively rare, it makes sense to take the (small)
       // performance hit here.
-      nsIContent* leftMostChild = GetLeftmostChild(mRootElement);
-      if (leftMostChild &&
-          EditorUtils::IsPaddingBRElementForEmptyEditor(*leftMostChild)) {
+      nsIContent* firstLeafChild = HTMLEditUtils::GetFirstLeafChild(
+          *mRootElement, ChildBlockBoundary::Ignore);
+      if (firstLeafChild &&
+          EditorUtils::IsPaddingBRElementForEmptyEditor(*firstLeafChild)) {
         mPaddingBRElementForEmptyEditor =
-            static_cast<HTMLBRElement*>(leftMostChild);
+            static_cast<HTMLBRElement*>(firstLeafChild);
       } else {
         mPaddingBRElementForEmptyEditor = nullptr;
       }
diff --git a/editor/libeditor/TypeInState.cpp b/editor/libeditor/TypeInState.cpp
index c51eff0673..8e4a170849 100644
--- a/editor/libeditor/TypeInState.cpp
+++ b/editor/libeditor/TypeInState.cpp
@@ -206,15 +206,9 @@ void TypeInState::ClearProp(nsAtom* aProp, nsAtom* aAttr) {
  * Caller assumes ownership of PropItem and must delete it.
  */
 UniquePtr<PropItem> TypeInState::TakeClearProperty() {
-  size_t count = mClearedArray.Length();
-  if (!count) {
-    return nullptr;
-  }
-
-  --count;  // indices are zero based
-  PropItem* propItem = mClearedArray[count];
-  mClearedArray.RemoveElementAt(count);
-  return UniquePtr<PropItem>(propItem);
+  return mClearedArray.Length()
+             ? UniquePtr<PropItem>{mClearedArray.PopLastElement()}
+             : nullptr;
 }
 
 /**
@@ -222,14 +216,8 @@ UniquePtr<PropItem> TypeInState::TakeClearProperty() {
  * Caller assumes ownership of PropItem and must delete it.
  */
 UniquePtr<PropItem> TypeInState::TakeSetProperty() {
-  size_t count = mSetArray.Length();
-  if (!count) {
-    return nullptr;
-  }
-  count--;  // indices are zero based
-  PropItem* propItem = mSetArray[count];
-  mSetArray.RemoveElementAt(count);
-  return UniquePtr<PropItem>(propItem);
+  return mSetArray.Length() ? UniquePtr<PropItem>{mSetArray.PopLastElement()}
+                            : nullptr;
 }
 
 /**
diff --git a/editor/libeditor/WSRunObject.cpp b/editor/libeditor/WSRunObject.cpp
index 16011dbd23..389fd42371 100644
--- a/editor/libeditor/WSRunObject.cpp
+++ b/editor/libeditor/WSRunObject.cpp
@@ -32,6 +32,8 @@ namespace mozilla {
 
 using namespace dom;
 
+using ChildBlockBoundary = HTMLEditUtils::ChildBlockBoundary;
+
 const char16_t kNBSP = 160;
 
 template WSRunScanner::WSRunScanner(const HTMLEditor* aHTMLEditor,
@@ -674,7 +676,7 @@ nsIContent* WSRunScanner::GetEditableBlockParentOrTopmotEditableInlineContent(
   //     it's not collapsed only when inserting composition string so that
   //     it's possible but shouldn't occur actually.
   nsIContent* editableBlockParentOrTopmotEditableInlineContent = nullptr;
-  for (nsIContent* content : InclusiveAncestorsOfType<nsIContent>(*aContent)) {
+  for (nsIContent* content : aContent->InclusiveAncestorsOfType<nsIContent>()) {
     if (!EditorUtils::IsEditableContent(*content, EditorType::HTML)) {
       break;
     }
@@ -743,16 +745,19 @@ nsresult WSRunScanner::GetWSNodes() {
 
   while (!mStartNode) {
     // we haven't found the start of ws yet.  Keep looking
-    nsCOMPtr<nsIContent> priorNode = GetPreviousWSNode(
-        start, editableBlockParentOrTopmotEditableInlineContent);
-    if (priorNode) {
-      if (HTMLEditUtils::IsBlockElement(*priorNode)) {
+    nsIContent* previousLeafContentOrBlock =
+        HTMLEditUtils::GetPreviousLeafContentOrPreviousBlockElement(
+            start, *editableBlockParentOrTopmotEditableInlineContent,
+            mEditingHost);
+    if (previousLeafContentOrBlock) {
+      if (HTMLEditUtils::IsBlockElement(*previousLeafContentOrBlock)) {
         mStartNode = start.GetContainer();
         mStartOffset = start.Offset();
         mStartReason = WSType::OtherBlockBoundary;
-        mStartReasonContent = priorNode;
-      } else if (priorNode->IsText() && priorNode->IsEditable()) {
-        RefPtr<Text> textNode = priorNode->AsText();
+        mStartReasonContent = previousLeafContentOrBlock;
+      } else if (previousLeafContentOrBlock->IsText() &&
+                 previousLeafContentOrBlock->IsEditable()) {
+        RefPtr<Text> textNode = previousLeafContentOrBlock->AsText();
         mNodeArray.InsertElementAt(0, textNode);
         const nsTextFragment* textFrag = &textNode->TextFragment();
         uint32_t len = textNode->TextLength();
@@ -760,7 +765,7 @@ nsresult WSRunScanner::GetWSNodes() {
         if (len < 1) {
           // Zero length text node. Set start point to it
           // so we can get past it!
-          start.Set(priorNode, 0);
+          start.Set(previousLeafContentOrBlock, 0);
         } else {
           for (int32_t pos = len - 1; pos >= 0; pos--) {
             // sanity bounds check the char position.  bug 136165
@@ -794,12 +799,12 @@ nsresult WSRunScanner::GetWSNodes() {
         // not a break but still serves as a terminator to ws runs.
         mStartNode = start.GetContainer();
         mStartOffset = start.Offset();
-        if (priorNode->IsHTMLElement(nsGkAtoms::br)) {
+        if (previousLeafContentOrBlock->IsHTMLElement(nsGkAtoms::br)) {
           mStartReason = WSType::BRElement;
         } else {
           mStartReason = WSType::SpecialContent;
         }
-        mStartReasonContent = priorNode;
+        mStartReasonContent = previousLeafContentOrBlock;
       }
     } else {
       // no prior node means we exhausted
@@ -849,17 +854,20 @@ nsresult WSRunScanner::GetWSNodes() {
 
   while (!mEndNode) {
     // we haven't found the end of ws yet.  Keep looking
-    nsCOMPtr<nsIContent> nextNode =
-        GetNextWSNode(end, editableBlockParentOrTopmotEditableInlineContent);
-    if (nextNode) {
-      if (HTMLEditUtils::IsBlockElement(*nextNode)) {
+    nsIContent* nextLeafContentOrBlock =
+        HTMLEditUtils::GetNextLeafContentOrNextBlockElement(
+            end, *editableBlockParentOrTopmotEditableInlineContent,
+            mEditingHost);
+    if (nextLeafContentOrBlock) {
+      if (HTMLEditUtils::IsBlockElement(*nextLeafContentOrBlock)) {
         // we encountered a new block.  therefore no more ws.
         mEndNode = end.GetContainer();
         mEndOffset = end.Offset();
         mEndReason = WSType::OtherBlockBoundary;
-        mEndReasonContent = nextNode;
-      } else if (nextNode->IsText() && nextNode->IsEditable()) {
-        RefPtr<Text> textNode = nextNode->AsText();
+        mEndReasonContent = nextLeafContentOrBlock;
+      } else if (nextLeafContentOrBlock->IsText() &&
+                 nextLeafContentOrBlock->IsEditable()) {
+        RefPtr<Text> textNode = nextLeafContentOrBlock->AsText();
         mNodeArray.AppendElement(textNode);
         const nsTextFragment* textFrag = &textNode->TextFragment();
         uint32_t len = textNode->TextLength();
@@ -902,12 +910,12 @@ nsresult WSRunScanner::GetWSNodes() {
         // serves as a terminator to ws runs.
         mEndNode = end.GetContainer();
         mEndOffset = end.Offset();
-        if (nextNode->IsHTMLElement(nsGkAtoms::br)) {
+        if (nextLeafContentOrBlock->IsHTMLElement(nsGkAtoms::br)) {
           mEndReason = WSType::BRElement;
         } else {
           mEndReason = WSType::SpecialContent;
         }
-        mEndReasonContent = nextNode;
+        mEndReasonContent = nextLeafContentOrBlock;
       }
     } else {
       // no next node means we exhausted
@@ -931,7 +939,9 @@ void WSRunScanner::GetRuns() {
   // the scan range isn't in preformatted element, we need to check only the
   // style at mScanStartPoint since the range would be replaced and the start
   // style will be applied to all new string.
-  mPRE = EditorBase::IsPreformatted(mScanStartPoint.GetContainer());
+  mPRE =
+      mScanStartPoint.IsInContentNode() &&
+      EditorUtils::IsContentPreformatted(*mScanStartPoint.ContainerAsContent());
   // if it's preformatedd, or if we are surrounded by text or special, it's all
   // one big normal ws run
   if (mPRE ||
@@ -1085,212 +1095,6 @@ void WSRunScanner::InitializeWithSingleFragment(
   mEndRun = mStartRun;
 }
 
-nsIContent* WSRunScanner::GetPreviousWSNodeInner(nsINode* aStartNode,
-                                                 nsINode* aBlockParent) const {
-  // Can't really recycle various getnext/prior routines because we have
-  // special needs here.  Need to step into inline containers but not block
-  // containers.
-  MOZ_ASSERT(aStartNode && aBlockParent);
-
-  if (aStartNode == mEditingHost) {
-    NS_WARNING(
-        "WSRunScanner::GetPreviousWSNodeInner() was called with editing host");
-    return nullptr;
-  }
-
-  nsCOMPtr<nsIContent> previousContent = aStartNode->GetPreviousSibling();
-  OwningNonNull<nsINode> curNode = *aStartNode;
-  while (!previousContent) {
-    // We have exhausted nodes in parent of aStartNode.
-    nsCOMPtr<nsINode> curParent = curNode->GetParentNode();
-    if (!curParent) {
-      NS_WARNING("Reached orphan node while climbing up the DOM tree");
-      return nullptr;
-    }
-    if (curParent == aBlockParent) {
-      // We have exhausted nodes in the block parent.  The convention here is
-      // to return null.
-      return nullptr;
-    }
-    if (curParent == mEditingHost) {
-      NS_WARNING("Reached editing host while climbing up the DOM tree");
-      return nullptr;
-    }
-    // We have a parent: look for previous sibling
-    previousContent = curParent->GetPreviousSibling();
-    curNode = curParent;
-  }
-
-  if (!previousContent) {
-    return nullptr;
-  }
-
-  // We have a prior node.  If it's a block, return it.
-  if (HTMLEditUtils::IsBlockElement(*previousContent)) {
-    return previousContent;
-  }
-  if (HTMLEditUtils::IsContainerNode(*previousContent)) {
-    // Else if it's a container, get deep rightmost child
-    nsCOMPtr<nsIContent> child =
-        mHTMLEditor->GetRightmostChild(previousContent);
-    if (child) {
-      return child;
-    }
-  }
-  // Else return the node itself
-  return previousContent;
-}
-
-nsIContent* WSRunScanner::GetPreviousWSNode(const EditorDOMPoint& aPoint,
-                                            nsINode* aBlockParent) const {
-  // Can't really recycle various getnext/prior routines because we
-  // have special needs here.  Need to step into inline containers but
-  // not block containers.
-  MOZ_ASSERT(aPoint.IsSet() && aBlockParent);
-
-  if (aPoint.IsInTextNode()) {
-    return GetPreviousWSNodeInner(aPoint.GetContainer(), aBlockParent);
-  }
-  if (!aPoint.IsInContentNode() ||
-      !HTMLEditUtils::IsContainerNode(*aPoint.ContainerAsContent())) {
-    return GetPreviousWSNodeInner(aPoint.GetContainer(), aBlockParent);
-  }
-
-  if (!aPoint.Offset()) {
-    if (aPoint.GetContainer() == aBlockParent) {
-      // We are at start of the block.
-      return nullptr;
-    }
-
-    // We are at start of non-block container
-    return GetPreviousWSNodeInner(aPoint.GetContainer(), aBlockParent);
-  }
-
-  if (NS_WARN_IF(!aPoint.IsInContentNode())) {
-    return nullptr;
-  }
-
-  nsCOMPtr<nsIContent> previousContent = aPoint.GetPreviousSiblingOfChild();
-  if (NS_WARN_IF(!previousContent)) {
-    return nullptr;
-  }
-
-  // We have a prior node.  If it's a block, return it.
-  if (HTMLEditUtils::IsBlockElement(*previousContent)) {
-    return previousContent;
-  }
-  if (HTMLEditUtils::IsContainerNode(*previousContent)) {
-    // Else if it's a container, get deep rightmost child
-    nsCOMPtr<nsIContent> child =
-        mHTMLEditor->GetRightmostChild(previousContent);
-    if (child) {
-      return child;
-    }
-  }
-  // Else return the node itself
-  return previousContent;
-}
-
-nsIContent* WSRunScanner::GetNextWSNodeInner(nsINode* aStartNode,
-                                             nsINode* aBlockParent) const {
-  // Can't really recycle various getnext/prior routines because we have
-  // special needs here.  Need to step into inline containers but not block
-  // containers.
-  MOZ_ASSERT(aStartNode && aBlockParent);
-
-  if (aStartNode == mEditingHost) {
-    NS_WARNING(
-        "WSRunScanner::GetNextWSNodeInner() was called with editing host");
-    return nullptr;
-  }
-
-  nsCOMPtr<nsIContent> nextContent = aStartNode->GetNextSibling();
-  nsCOMPtr<nsINode> curNode = aStartNode;
-  while (!nextContent) {
-    // We have exhausted nodes in parent of aStartNode.
-    nsCOMPtr<nsINode> curParent = curNode->GetParentNode();
-    if (!curParent) {
-      NS_WARNING("Reached orphan node while climbing up the DOM tree");
-      return nullptr;
-    }
-    if (curParent == aBlockParent) {
-      // We have exhausted nodes in the block parent.  The convention here is
-      // to return null.
-      return nullptr;
-    }
-    if (curParent == mEditingHost) {
-      NS_WARNING("Reached editing host while climbing up the DOM tree");
-      return nullptr;
-    }
-    // We have a parent: look for next sibling
-    nextContent = curParent->GetNextSibling();
-    curNode = curParent;
-  }
-
-  if (!nextContent) {
-    return nullptr;
-  }
-
-  // We have a next node.  If it's a block, return it.
-  if (HTMLEditUtils::IsBlockElement(*nextContent)) {
-    return nextContent;
-  }
-  if (HTMLEditUtils::IsContainerNode(*nextContent)) {
-    // Else if it's a container, get deep leftmost child
-    nsCOMPtr<nsIContent> child = mHTMLEditor->GetLeftmostChild(nextContent);
-    if (child) {
-      return child;
-    }
-  }
-  // Else return the node itself
-  return nextContent;
-}
-
-nsIContent* WSRunScanner::GetNextWSNode(const EditorDOMPoint& aPoint,
-                                        nsINode* aBlockParent) const {
-  // Can't really recycle various getnext/prior routines because we have
-  // special needs here.  Need to step into inline containers but not block
-  // containers.
-  MOZ_ASSERT(aPoint.IsSet() && aBlockParent);
-
-  if (aPoint.IsInTextNode()) {
-    return GetNextWSNodeInner(aPoint.GetContainer(), aBlockParent);
-  }
-  if (!aPoint.IsInContentNode() ||
-      !HTMLEditUtils::IsContainerNode(*aPoint.ContainerAsContent())) {
-    return GetNextWSNodeInner(aPoint.GetContainer(), aBlockParent);
-  }
-
-  if (NS_WARN_IF(!aPoint.IsInContentNode())) {
-    return nullptr;
-  }
-
-  nsCOMPtr<nsIContent> nextContent = aPoint.GetChild();
-  if (!nextContent) {
-    if (aPoint.GetContainer() == aBlockParent) {
-      // We are at end of the block.
-      return nullptr;
-    }
-
-    // We are at end of non-block container
-    return GetNextWSNodeInner(aPoint.GetContainer(), aBlockParent);
-  }
-
-  // We have a next node.  If it's a block, return it.
-  if (HTMLEditUtils::IsBlockElement(*nextContent)) {
-    return nextContent;
-  }
-  if (HTMLEditUtils::IsContainerNode(*nextContent)) {
-    // else if it's a container, get deep leftmost child
-    nsCOMPtr<nsIContent> child = mHTMLEditor->GetLeftmostChild(nextContent);
-    if (child) {
-      return child;
-    }
-  }
-  // Else return the node itself
-  return nextContent;
-}
-
 nsresult WSRunObject::PrepareToDeleteRangePriv(WSRunObject* aEndObject) {
   // this routine adjust whitespace before *this* and after aEndObject
   // in preperation for the two areas to become adjacent after the
diff --git a/editor/libeditor/WSRunObject.h b/editor/libeditor/WSRunObject.h
index 847d654fa7..e4821bf5a7 100644
--- a/editor/libeditor/WSRunObject.h
+++ b/editor/libeditor/WSRunObject.h
@@ -574,15 +574,6 @@ class MOZ_STACK_CLASS WSRunScanner {
   nsIContent* GetEditableBlockParentOrTopmotEditableInlineContent(
       nsIContent* aContent) const;
 
-  nsIContent* GetPreviousWSNodeInner(nsINode* aStartNode,
-                                     nsINode* aBlockParent) const;
-  nsIContent* GetPreviousWSNode(const EditorDOMPoint& aPoint,
-                                nsINode* aBlockParent) const;
-  nsIContent* GetNextWSNodeInner(nsINode* aStartNode,
-                                 nsINode* aBlockParent) const;
-  nsIContent* GetNextWSNode(const EditorDOMPoint& aPoint,
-                            nsINode* aBlockParent) const;
-
   /**
    * GetPreviousCharPoint() and GetPreviousCharPointFromPointInText() return
    * previous character's point of of aPoint. If there is no character before
diff --git a/editor/libeditor/tests/test_cut_copy_password.html b/editor/libeditor/tests/test_cut_copy_password.html
index a1998d459e..e15682cf97 100644
--- a/editor/libeditor/tests/test_cut_copy_password.html
+++ b/editor/libeditor/tests/test_cut_copy_password.html
@@ -13,29 +13,23 @@ SimpleTest.waitForFocus(async () => {
   let input = document.getElementsByTagName("input")[0];
   let editor = SpecialPowers.wrap(input).editor;
   const kMask = editor.passwordMask;
-  function copyToClipboard(aExpectedValue) {
-    return new Promise(async resolve => {
-      try {
-        await SimpleTest.promiseClipboardChange(
-            aExpectedValue, () => { SpecialPowers.doCommand(window, "cmd_copy"); },
-            undefined, undefined, aExpectedValue === null);
-      } catch (e) {
-        console.error(e);
-      }
-      resolve();
-    });
+  async function copyToClipboard(aExpectedValue) {
+    try {
+      await SimpleTest.promiseClipboardChange(
+          aExpectedValue, () => { SpecialPowers.doCommand(window, "cmd_copy"); },
+          undefined, undefined, aExpectedValue === null);
+    } catch (e) {
+      console.error(e);
+    }
   }
-  function cutToClipboard(aExpectedValue) {
-    return new Promise(async resolve => {
-      try {
-        await SimpleTest.promiseClipboardChange(
-            aExpectedValue, () => { SpecialPowers.doCommand(window, "cmd_cut"); },
-            undefined, undefined, aExpectedValue === null);
-      } catch (e) {
-        console.error(e);
-      }
-      resolve();
-    });
+  async function cutToClipboard(aExpectedValue) {
+    try {
+      await SimpleTest.promiseClipboardChange(
+          aExpectedValue, () => { SpecialPowers.doCommand(window, "cmd_cut"); },
+          undefined, undefined, aExpectedValue === null);
+    } catch (e) {
+      console.error(e);
+    }
   }
   input.value = "abcdef";
   input.focus();
diff --git a/editor/libeditor/tests/test_nsIHTMLEditor_getSelectedElement.html b/editor/libeditor/tests/test_nsIHTMLEditor_getSelectedElement.html
index 99dd9ca9f2..255f5b7a7c 100644
--- a/editor/libeditor/tests/test_nsIHTMLEditor_getSelectedElement.html
+++ b/editor/libeditor/tests/test_nsIHTMLEditor_getSelectedElement.html
@@ -779,6 +779,27 @@ SimpleTest.waitForFocus(async function() {
      null,
      "#9-1 nsIHTMLEditor::getSelectedElement(\"anchor\") should return null when Selection starts from a text node in <b> element and ends before the following <br> element");
 
+  editor.innerHTML = "<p><b>b1</b><b><br></b><b>b2</b></p>";
+  editor.focus();
+
+  // <p><b>[b1</b><b>}<br></b><b>b2</b></p>
+  // This is usual case of double-clicking in the first <b> element.
+  range = document.createRange();
+  range.setStart(editor.firstChild.firstChild.firstChild, 0);
+  range.setEnd(editor.firstChild.firstChild.nextSibling, 0);
+  selection.removeAllRanges();
+  selection.addRange(range);
+
+  is(SpecialPowers.unwrap(getHTMLEditor().getSelectedElement("")),
+     null,
+     "#10-1 nsIHTMLEditor::getSelectedElement(\"\") should return null when Selection starts from a text node in <b> element and ends before the following <br> element in another <b> element");
+  is(SpecialPowers.unwrap(getHTMLEditor().getSelectedElement("href")),
+     null,
+     "#10-1 nsIHTMLEditor::getSelectedElement(\"href\") should return null when Selection starts from a text node in <b> element and ends before the following <br> element in another <b> element");
+  is(SpecialPowers.unwrap(getHTMLEditor().getSelectedElement("anchor")),
+     null,
+     "#10-1 nsIHTMLEditor::getSelectedElement(\"anchor\") should return null when Selection starts from a text node in <b> element and ends before the following <br> element in another <b> element");
+
   SimpleTest.finish();
 });
 
diff --git a/extensions/permissions/components.conf b/extensions/permissions/components.conf
index 07c5ff7ffa..d7d65bb1ba 100644
--- a/extensions/permissions/components.conf
+++ b/extensions/permissions/components.conf
@@ -12,8 +12,10 @@ Classes = [
         'categories': {'content-policy': '@mozilla.org/permissions/contentblocker;1'},
     },
     {
+        'js_name': 'perms',
         'cid': '{4f6b5e00-0c36-11d5-a535-0010a401eb10}',
         'contract_ids': ['@mozilla.org/permissionmanager;1'],
+        'interfaces': ['nsIPermissionManager'],
         'singleton': True,
         'type': 'nsIPermissionManager',
         'constructor': 'nsPermissionManager::GetXPCOMSingleton',
diff --git a/extensions/permissions/nsPermissionManager.cpp b/extensions/permissions/nsPermissionManager.cpp
index 39868e0eac..b37fb29497 100644
--- a/extensions/permissions/nsPermissionManager.cpp
+++ b/extensions/permissions/nsPermissionManager.cpp
@@ -8,7 +8,6 @@
 #include "mozilla/BasePrincipal.h"
 #include "mozilla/ContentPrincipal.h"
 #include "mozilla/DebugOnly.h"
-#include "mozilla/Pair.h"
 #include "mozilla/Services.h"
 #include "mozilla/SystemGroup.h"
 #include "nsPermissionManager.h"
@@ -2130,7 +2129,7 @@ nsPermissionManager::RemoveAllSince(int64_t aSince) {
 
 template <class T>
 nsresult nsPermissionManager::RemovePermissionEntries(T aCondition) {
-  Vector<Pair<nsCOMPtr<nsIPrincipal>, nsCString>, 10> array;
+  Vector<std::pair<nsCOMPtr<nsIPrincipal>, nsCString>, 10> array;
   for (auto iter = mPermissionTable.Iter(); !iter.Done(); iter.Next()) {
     PermissionHashKey* entry = iter.Get();
     for (const auto& permEntry : entry->GetPermissions()) {
@@ -2153,7 +2152,7 @@ nsresult nsPermissionManager::RemovePermissionEntries(T aCondition) {
 
   for (auto& i : array) {
     // AddInternal handles removal, so let it do the work...
-    AddInternal(i.first(), i.second(), nsIPermissionManager::UNKNOWN_ACTION, 0,
+    AddInternal(i.first, i.second, nsIPermissionManager::UNKNOWN_ACTION, 0,
                 nsIPermissionManager::EXPIRE_NEVER, 0, 0,
                 nsPermissionManager::eNotify, nsPermissionManager::eWriteToDB);
   }
@@ -2679,7 +2678,7 @@ nsresult nsPermissionManager::RemovePermissionsWithAttributes(
 
 nsresult nsPermissionManager::RemovePermissionsWithAttributes(
     mozilla::OriginAttributesPattern& aPattern) {
-  Vector<Pair<nsCOMPtr<nsIPrincipal>, nsCString>, 10> permissions;
+  Vector<std::pair<nsCOMPtr<nsIPrincipal>, nsCString>, 10> permissions;
   for (auto iter = mPermissionTable.Iter(); !iter.Done(); iter.Next()) {
     PermissionHashKey* entry = iter.Get();
 
@@ -2702,7 +2701,7 @@ nsresult nsPermissionManager::RemovePermissionsWithAttributes(
   }
 
   for (auto& i : permissions) {
-    AddInternal(i.first(), i.second(), nsIPermissionManager::UNKNOWN_ACTION, 0,
+    AddInternal(i.first, i.second, nsIPermissionManager::UNKNOWN_ACTION, 0,
                 nsIPermissionManager::EXPIRE_NEVER, 0, 0,
                 nsPermissionManager::eNotify, nsPermissionManager::eWriteToDB);
   }
diff --git a/gfx/2d/BasePoint.h b/gfx/2d/BasePoint.h
index e4ac67b61a..7e2a5ebc7c 100644
--- a/gfx/2d/BasePoint.h
+++ b/gfx/2d/BasePoint.h
@@ -7,6 +7,7 @@
 
 #include <cmath>
 #include <ostream>
+#include <type_traits>
 #include "mozilla/Attributes.h"
 #include "mozilla/FloatingPoint.h"
 #include "mozilla/TypeTraits.h"
@@ -93,8 +94,8 @@ struct BasePoint {
 
   // "Finite" means not inf and not NaN
   bool IsFinite() const {
-    typedef typename mozilla::Conditional<mozilla::IsSame<T, float>::value,
-                                          float, double>::Type FloatType;
+    using FloatType =
+        std::conditional_t<mozilla::IsSame<T, float>::value, float, double>;
     return (mozilla::IsFinite(FloatType(x)) && mozilla::IsFinite(FloatType(y)));
     return true;
   }
diff --git a/gfx/2d/BaseRect.h b/gfx/2d/BaseRect.h
index debbd83f1e..7de91e1ef6 100644
--- a/gfx/2d/BaseRect.h
+++ b/gfx/2d/BaseRect.h
@@ -8,6 +8,7 @@
 #include <algorithm>
 #include <cmath>
 #include <ostream>
+#include <type_traits>
 
 #include "mozilla/Assertions.h"
 #include "mozilla/FloatingPoint.h"
@@ -62,8 +63,8 @@ struct BaseRect {
 
   // "Finite" means not inf and not NaN
   bool IsFinite() const {
-    typedef typename mozilla::Conditional<mozilla::IsSame<T, float>::value,
-                                          float, double>::Type FloatType;
+    using FloatType =
+        std::conditional_t<mozilla::IsSame<T, float>::value, float, double>;
     return (mozilla::IsFinite(FloatType(x)) &&
             mozilla::IsFinite(FloatType(y)) &&
             mozilla::IsFinite(FloatType(width)) &&
diff --git a/gfx/2d/GenericRefCounted.h b/gfx/2d/GenericRefCounted.h
index 7a552a28c7..dbc0a04483 100644
--- a/gfx/2d/GenericRefCounted.h
+++ b/gfx/2d/GenericRefCounted.h
@@ -9,6 +9,8 @@
 #ifndef MOZILLA_GENERICREFCOUNTED_H_
 #define MOZILLA_GENERICREFCOUNTED_H_
 
+#include <type_traits>
+
 #include "mozilla/RefPtr.h"
 #include "mozilla/RefCounted.h"
 
@@ -99,8 +101,9 @@ class GenericRefCounted : public GenericRefCountedBase {
   }
 
  private:
-  typename Conditional<Atomicity == AtomicRefCount, Atomic<MozRefCountType>,
-                       MozRefCountType>::Type refCnt;
+  std::conditional_t<Atomicity == AtomicRefCount, Atomic<MozRefCountType>,
+                     MozRefCountType>
+      refCnt;
 };
 
 }  // namespace detail
diff --git a/gfx/ipc/GPUProcessManager.h b/gfx/ipc/GPUProcessManager.h
index 5322ea4831..643d715d7e 100644
--- a/gfx/ipc/GPUProcessManager.h
+++ b/gfx/ipc/GPUProcessManager.h
@@ -181,6 +181,9 @@ class GPUProcessManager final : public GPUProcessHost::Listener {
   // Returns whether or not a GPU process was ever launched.
   bool AttemptedGPUProcess() const { return mNumProcessAttempts > 0; }
 
+  // Returns the process host
+  GPUProcessHost* Process() { return mProcess; }
+
  private:
   // Called from our xpcom-shutdown observer.
   void OnXPCOMShutdown();
diff --git a/gfx/layers/AnimationInfo.cpp b/gfx/layers/AnimationInfo.cpp
index 3694a378b8..bb661f9c94 100644
--- a/gfx/layers/AnimationInfo.cpp
+++ b/gfx/layers/AnimationInfo.cpp
@@ -131,7 +131,7 @@ void AnimationInfo::TransferMutatedFlagToLayer(Layer* aLayer) {
 
 bool AnimationInfo::ApplyPendingUpdatesForThisTransaction() {
   if (mPendingAnimations) {
-    mPendingAnimations->SwapElements(mAnimations);
+    mAnimations = std::move(*mPendingAnimations);
     mPendingAnimations = nullptr;
     return true;
   }
diff --git a/gfx/layers/ImageContainer.cpp b/gfx/layers/ImageContainer.cpp
index 86596c63a1..460fc8322d 100644
--- a/gfx/layers/ImageContainer.cpp
+++ b/gfx/layers/ImageContainer.cpp
@@ -85,10 +85,7 @@ UniquePtr<uint8_t[]> BufferRecycleBin::GetBuffer(uint32_t aSize) {
     return UniquePtr<uint8_t[]>(new (fallible) uint8_t[aSize]);
   }
 
-  uint32_t last = mRecycledBuffers.Length() - 1;
-  UniquePtr<uint8_t[]> result = std::move(mRecycledBuffers[last]);
-  mRecycledBuffers.RemoveElementAt(last);
-  return result;
+  return mRecycledBuffers.PopLastElement();
 }
 
 void BufferRecycleBin::ClearRecycledBuffers() {
@@ -289,7 +286,7 @@ void ImageContainer::SetCurrentImageInternal(
     }
   }
 
-  mCurrentImages.SwapElements(newImages);
+  mCurrentImages = std::move(newImages);
 }
 
 void ImageContainer::ClearImagesFromImageBridge() {
diff --git a/gfx/layers/LayerSorter.cpp b/gfx/layers/LayerSorter.cpp
index d829ee3d3d..6a831be9bf 100644
--- a/gfx/layers/LayerSorter.cpp
+++ b/gfx/layers/LayerSorter.cpp
@@ -299,12 +299,9 @@ void SortLayersBy3DZOrder(nsTArray<Layer*>& aLayers) {
   // and remove edges from it.
   do {
     if (!noIncoming.IsEmpty()) {
-      uint32_t last = noIncoming.Length() - 1;
-
-      Layer* layer = noIncoming.ElementAt(last);
+      Layer* layer = noIncoming.PopLastElement();
       MOZ_ASSERT(layer);  // don't let null layer pointers sneak into sortedList
 
-      noIncoming.RemoveElementAt(last);
       sortedList.AppendElement(layer);
 
       nsTArray<DirectedGraph<Layer*>::Edge> outgoing;
diff --git a/gfx/layers/Layers.cpp b/gfx/layers/Layers.cpp
index b873818e80..fd11bdbc9c 100644
--- a/gfx/layers/Layers.cpp
+++ b/gfx/layers/Layers.cpp
@@ -2321,12 +2321,12 @@ void RecordCompositionPayloadsPresented(
     TimeStamp presented = TimeStamp::Now();
     for (const CompositionPayload& payload : aPayloads) {
 #if MOZ_GECKO_PROFILER
-      if (profiler_is_active()) {
+      if (profiler_can_accept_markers()) {
         nsPrintfCString marker(
             "Payload Presented, type: %d latency: %dms\n",
             int32_t(payload.mType),
             int32_t((presented - payload.mTimeStamp).ToMilliseconds()));
-        profiler_add_marker(marker.get(), JS::ProfilingCategoryPair::GRAPHICS);
+        PROFILER_ADD_MARKER(marker.get(), GRAPHICS);
       }
 #endif
 
diff --git a/gfx/layers/ProfilerScreenshots.cpp b/gfx/layers/ProfilerScreenshots.cpp
index 2c906dcb61..2ad0973408 100644
--- a/gfx/layers/ProfilerScreenshots.cpp
+++ b/gfx/layers/ProfilerScreenshots.cpp
@@ -66,7 +66,7 @@ void ProfilerScreenshots::SubmitScreenshot(
        originalSize, scaledSize, timeStamp]() {
         // Create a new surface that wraps backingSurface's data but has the
         // correct size.
-        {
+        if (profiler_can_accept_markers()) {
           DataSourceSurface::ScopedMap scopedMap(backingSurface,
                                                  DataSourceSurface::READ);
           RefPtr<DataSourceSurface> surf =
@@ -81,6 +81,7 @@ void ProfilerScreenshots::SubmitScreenshot(
               gfxUtils::eDataURIEncode, nullptr, &dataURL);
           if (NS_SUCCEEDED(rv)) {
             // Add a marker with the data URL.
+            AUTO_PROFILER_STATS(add_marker_with_ScreenshotPayload);
             profiler_add_marker_for_thread(
                 sourceThread, JS::ProfilingCategoryPair::GRAPHICS,
                 "CompositorScreenshot",
diff --git a/gfx/layers/TreeTraversal.h b/gfx/layers/TreeTraversal.h
index 6b358e8829..8f6c2e3547 100644
--- a/gfx/layers/TreeTraversal.h
+++ b/gfx/layers/TreeTraversal.h
@@ -6,6 +6,7 @@
 #define mozilla_layers_TreeTraversal_h
 
 #include <queue>
+#include <type_traits>
 
 namespace mozilla {
 namespace layers {
@@ -84,11 +85,11 @@ class ReverseIterator {
 template <typename Iterator, typename Node, typename PreAction,
           typename PostAction>
 static auto ForEachNode(Node aRoot, const PreAction& aPreAction,
-                        const PostAction& aPostAction) ->
-    typename EnableIf<
+                        const PostAction& aPostAction)
+    -> std::enable_if_t<
         IsSame<decltype(aPreAction(aRoot)), TraversalFlag>::value &&
             IsSame<decltype(aPostAction(aRoot)), TraversalFlag>::value,
-        bool>::Type {
+        bool> {
   if (!aRoot) {
     return false;
   }
@@ -125,10 +126,10 @@ static auto ForEachNode(Node aRoot, const PreAction& aPreAction,
 template <typename Iterator, typename Node, typename PreAction,
           typename PostAction>
 static auto ForEachNode(Node aRoot, const PreAction& aPreAction,
-                        const PostAction& aPostAction) ->
-    typename EnableIf<IsSame<decltype(aPreAction(aRoot)), void>::value &&
-                          IsSame<decltype(aPostAction(aRoot)), void>::value,
-                      void>::Type {
+                        const PostAction& aPostAction)
+    -> std::enable_if_t<IsSame<decltype(aPreAction(aRoot)), void>::value &&
+                            IsSame<decltype(aPostAction(aRoot)), void>::value,
+                        void> {
   if (!aRoot) {
     return;
   }
@@ -147,9 +148,8 @@ static auto ForEachNode(Node aRoot, const PreAction& aPreAction,
  * ForEachNode pre-order traversal, using TraversalFlag.
  */
 template <typename Iterator, typename Node, typename PreAction>
-auto ForEachNode(Node aRoot, const PreAction& aPreAction) ->
-    typename EnableIf<IsSame<decltype(aPreAction(aRoot)), TraversalFlag>::value,
-                      bool>::Type {
+auto ForEachNode(Node aRoot, const PreAction& aPreAction) -> std::enable_if_t<
+    IsSame<decltype(aPreAction(aRoot)), TraversalFlag>::value, bool> {
   return ForEachNode<Iterator>(
       aRoot, aPreAction, [](Node aNode) { return TraversalFlag::Continue; });
 }
@@ -158,9 +158,9 @@ auto ForEachNode(Node aRoot, const PreAction& aPreAction) ->
  * ForEachNode pre-order, not using TraversalFlag.
  */
 template <typename Iterator, typename Node, typename PreAction>
-auto ForEachNode(Node aRoot, const PreAction& aPreAction) ->
-    typename EnableIf<IsSame<decltype(aPreAction(aRoot)), void>::value,
-                      void>::Type {
+auto ForEachNode(Node aRoot, const PreAction& aPreAction)
+    -> std::enable_if_t<IsSame<decltype(aPreAction(aRoot)), void>::value,
+                        void> {
   ForEachNode<Iterator>(aRoot, aPreAction, [](Node aNode) {});
 }
 
@@ -168,10 +168,9 @@ auto ForEachNode(Node aRoot, const PreAction& aPreAction) ->
  * ForEachNode post-order traversal, using TraversalFlag.
  */
 template <typename Iterator, typename Node, typename PostAction>
-auto ForEachNodePostOrder(Node aRoot, const PostAction& aPostAction) ->
-    typename EnableIf<
-        IsSame<decltype(aPostAction(aRoot)), TraversalFlag>::value,
-        bool>::Type {
+auto ForEachNodePostOrder(Node aRoot, const PostAction& aPostAction)
+    -> std::enable_if_t<
+        IsSame<decltype(aPostAction(aRoot)), TraversalFlag>::value, bool> {
   return ForEachNode<Iterator>(
       aRoot, [](Node aNode) { return TraversalFlag::Continue; }, aPostAction);
 }
@@ -180,9 +179,9 @@ auto ForEachNodePostOrder(Node aRoot, const PostAction& aPostAction) ->
  * ForEachNode post-order, not using TraversalFlag.
  */
 template <typename Iterator, typename Node, typename PostAction>
-auto ForEachNodePostOrder(Node aRoot, const PostAction& aPostAction) ->
-    typename EnableIf<IsSame<decltype(aPostAction(aRoot)), void>::value,
-                      void>::Type {
+auto ForEachNodePostOrder(Node aRoot, const PostAction& aPostAction)
+    -> std::enable_if_t<IsSame<decltype(aPostAction(aRoot)), void>::value,
+                        void> {
   ForEachNode<Iterator>(
       aRoot, [](Node aNode) {}, aPostAction);
 }
diff --git a/gfx/layers/apz/test/gtest/APZTestCommon.h b/gfx/layers/apz/test/gtest/APZTestCommon.h
index 9c26e414be..4cde2d644d 100644
--- a/gfx/layers/apz/test/gtest/APZTestCommon.h
+++ b/gfx/layers/apz/test/gtest/APZTestCommon.h
@@ -191,8 +191,8 @@ class MockContentControllerDelayed : public MockContentController {
   // in the queue after this function is called. Only when the return
   // value is 0 is the queue guaranteed to be empty.
   int RunThroughDelayedTasks() {
-    nsTArray<std::pair<RefPtr<Runnable>, TimeStamp>> runQueue;
-    runQueue.SwapElements(mTaskQueue);
+    nsTArray<std::pair<RefPtr<Runnable>, TimeStamp>> runQueue =
+        std::move(mTaskQueue);
     int numTasks = runQueue.Length();
     for (int i = 0; i < numTasks; i++) {
       mTime = runQueue[i].second;
diff --git a/gfx/layers/client/MultiTiledContentClient.cpp b/gfx/layers/client/MultiTiledContentClient.cpp
index 28bd927edb..c87484d971 100644
--- a/gfx/layers/client/MultiTiledContentClient.cpp
+++ b/gfx/layers/client/MultiTiledContentClient.cpp
@@ -186,8 +186,7 @@ void ClientMultiTiledLayerBuffer::Update(const nsIntRegion& newValidRegion,
   const size_t oldTileCount = mRetainedTiles.Length();
   const size_t newTileCount = newTiles.mSize.width * newTiles.mSize.height;
 
-  nsTArray<TileClient> oldRetainedTiles;
-  mRetainedTiles.SwapElements(oldRetainedTiles);
+  nsTArray<TileClient> oldRetainedTiles = std::move(mRetainedTiles);
   mRetainedTiles.SetLength(newTileCount);
 
   for (size_t oldIndex = 0; oldIndex < oldTileCount; oldIndex++) {
diff --git a/gfx/layers/client/TextureClient.h b/gfx/layers/client/TextureClient.h
index 238bcb72af..337ca03857 100644
--- a/gfx/layers/client/TextureClient.h
+++ b/gfx/layers/client/TextureClient.h
@@ -771,14 +771,10 @@ class TextureClientReleaseTask : public Runnable {
 // Automatically lock and unlock a texture. Since texture locking is fallible,
 // Succeeded() must be checked on the guard object before proceeding.
 class MOZ_RAII TextureClientAutoLock {
-  MOZ_DECL_USE_GUARD_OBJECT_NOTIFIER;
 
  public:
-  TextureClientAutoLock(TextureClient* aTexture,
-                        OpenMode aMode MOZ_GUARD_OBJECT_NOTIFIER_PARAM)
+  TextureClientAutoLock(TextureClient* aTexture, OpenMode aMode)
       : mTexture(aTexture), mSucceeded(false) {
-    MOZ_GUARD_OBJECT_NOTIFIER_INIT;
-
     mSucceeded = mTexture->Lock(aMode);
 #ifdef DEBUG
     mChecked = false;
diff --git a/gfx/layers/composite/CompositorScreenshotGrabber.cpp b/gfx/layers/composite/CompositorScreenshotGrabber.cpp
index aa54021aa6..ee861a17f3 100644
--- a/gfx/layers/composite/CompositorScreenshotGrabber.cpp
+++ b/gfx/layers/composite/CompositorScreenshotGrabber.cpp
@@ -85,8 +85,8 @@ void CompositorScreenshotGrabber::MaybeProcessQueue() {
 
 void CompositorScreenshotGrabber::NotifyEmptyFrame() {
 #ifdef MOZ_GECKO_PROFILER
-  profiler_add_marker("NoCompositorScreenshot because nothing changed",
-                      JS::ProfilingCategoryPair::GRAPHICS);
+  PROFILER_ADD_MARKER("NoCompositorScreenshot because nothing changed",
+                      GRAPHICS);
 #endif
 }
 
diff --git a/gfx/layers/composite/ContainerLayerComposite.cpp b/gfx/layers/composite/ContainerLayerComposite.cpp
index f0d6e775ff..5ac3f2323b 100644
--- a/gfx/layers/composite/ContainerLayerComposite.cpp
+++ b/gfx/layers/composite/ContainerLayerComposite.cpp
@@ -100,9 +100,9 @@ static void PrintUniformityInfo(Layer* aLayer) {
   }
 
   Point translation = transform.As2D().GetTranslation();
-  profiler_add_marker("LayerTranslation", JS::ProfilingCategoryPair::GRAPHICS,
-                      MakeUnique<LayerTranslationMarkerPayload>(
-                          aLayer, translation, TimeStamp::Now()));
+  PROFILER_ADD_MARKER_WITH_PAYLOAD("LayerTranslation", GRAPHICS,
+                                   LayerTranslationMarkerPayload,
+                                   (aLayer, translation, TimeStamp::Now()));
 #endif
 }
 
diff --git a/gfx/layers/ipc/CompositorBridgeChild.cpp b/gfx/layers/ipc/CompositorBridgeChild.cpp
index 4640b70a04..d5b7a96110 100644
--- a/gfx/layers/ipc/CompositorBridgeChild.cpp
+++ b/gfx/layers/ipc/CompositorBridgeChild.cpp
@@ -51,7 +51,6 @@
 #include "VsyncSource.h"
 
 using mozilla::Unused;
-using mozilla::dom::BrowserChildBase;
 using mozilla::gfx::GPUProcessManager;
 using mozilla::layers::LayerTransactionChild;
 
@@ -645,17 +644,15 @@ mozilla::ipc::IPCResult CompositorBridgeChild::RecvRemotePaintIsReady() {
   // do_QueryReference so I'm using static_cast<>
   MOZ_LAYERS_LOG(
       ("[RemoteGfx] CompositorBridgeChild received RemotePaintIsReady"));
-  RefPtr<nsISupports> iBrowserChildBase(do_QueryReferent(mWeakBrowserChild));
-  if (!iBrowserChildBase) {
+  RefPtr<nsIBrowserChild> iBrowserChild(do_QueryReferent(mWeakBrowserChild));
+  if (!iBrowserChild) {
     MOZ_LAYERS_LOG(
         ("[RemoteGfx] Note: BrowserChild was released before "
          "RemotePaintIsReady. "
          "MozAfterRemotePaint will not be sent to listener."));
     return IPC_OK();
   }
-  BrowserChildBase* browserChildBase =
-      static_cast<BrowserChildBase*>(iBrowserChildBase.get());
-  BrowserChild* browserChild = static_cast<BrowserChild*>(browserChildBase);
+  BrowserChild* browserChild = static_cast<BrowserChild*>(iBrowserChild.get());
   MOZ_ASSERT(browserChild);
   Unused << browserChild->SendRemotePaintIsReady();
   mWeakBrowserChild = nullptr;
@@ -668,7 +665,7 @@ void CompositorBridgeChild::RequestNotifyAfterRemotePaint(
              "NULL BrowserChild not allowed in "
              "CompositorBridgeChild::RequestNotifyAfterRemotePaint");
   mWeakBrowserChild =
-      do_GetWeakReference(static_cast<dom::BrowserChildBase*>(aBrowserChild));
+      do_GetWeakReference(static_cast<dom::BrowserChild*>(aBrowserChild));
   if (!mCanSend) {
     return;
   }
@@ -677,13 +674,11 @@ void CompositorBridgeChild::RequestNotifyAfterRemotePaint(
 
 void CompositorBridgeChild::CancelNotifyAfterRemotePaint(
     BrowserChild* aBrowserChild) {
-  RefPtr<nsISupports> iBrowserChildBase(do_QueryReferent(mWeakBrowserChild));
-  if (!iBrowserChildBase) {
+  RefPtr<nsIBrowserChild> iBrowserChild(do_QueryReferent(mWeakBrowserChild));
+  if (!iBrowserChild) {
     return;
   }
-  BrowserChildBase* browserChildBase =
-      static_cast<BrowserChildBase*>(iBrowserChildBase.get());
-  BrowserChild* browserChild = static_cast<BrowserChild*>(browserChildBase);
+  BrowserChild* browserChild = static_cast<BrowserChild*>(iBrowserChild.get());
   if (browserChild == aBrowserChild) {
     mWeakBrowserChild = nullptr;
   }
diff --git a/gfx/layers/ipc/CompositorBridgeParent.cpp b/gfx/layers/ipc/CompositorBridgeParent.cpp
index f8f1ec41a7..e9ee5c1ce1 100644
--- a/gfx/layers/ipc/CompositorBridgeParent.cpp
+++ b/gfx/layers/ipc/CompositorBridgeParent.cpp
@@ -2131,8 +2131,8 @@ already_AddRefed<IAPZCTreeManager> CompositorBridgeParent::GetAPZCTreeManager(
 static void InsertVsyncProfilerMarker(TimeStamp aVsyncTimestamp) {
   MOZ_ASSERT(CompositorThreadHolder::IsInCompositorThread());
   if (profiler_thread_is_being_profiled()) {
-    profiler_add_marker("VsyncTimestamp", JS::ProfilingCategoryPair::GRAPHICS,
-                        MakeUnique<VsyncMarkerPayload>(aVsyncTimestamp));
+    PROFILER_ADD_MARKER_WITH_PAYLOAD("VsyncTimestamp", GRAPHICS,
+                                     VsyncMarkerPayload, (aVsyncTimestamp));
   }
 }
 #endif
@@ -2685,19 +2685,40 @@ int32_t RecordContentFrameTime(const VsyncId& aTxnId,
   int32_t fracLatencyNorm = lround(latencyNorm * 100.0);
 
 #ifdef MOZ_GECKO_PROFILER
-  if (profiler_is_active()) {
+  if (profiler_can_accept_markers()) {
     class ContentFramePayload : public ProfilerMarkerPayload {
      public:
       ContentFramePayload(const mozilla::TimeStamp& aStartTime,
                           const mozilla::TimeStamp& aEndTime)
           : ProfilerMarkerPayload(aStartTime, aEndTime) {}
-      virtual void StreamPayload(SpliceableJSONWriter& aWriter,
-                                 const TimeStamp& aProcessStartTime,
-                                 UniqueStacks& aUniqueStacks) override {
+      mozilla::BlocksRingBuffer::Length TagAndSerializationBytes()
+          const override {
+        return CommonPropsTagAndSerializationBytes();
+      }
+      void SerializeTagAndPayload(
+          mozilla::BlocksRingBuffer::EntryWriter& aEntryWriter) const override {
+        static const DeserializerTag tag = TagForDeserializer(Deserialize);
+        SerializeTagAndCommonProps(tag, aEntryWriter);
+      }
+      void StreamPayload(SpliceableJSONWriter& aWriter,
+                         const TimeStamp& aProcessStartTime,
+                         UniqueStacks& aUniqueStacks) const override {
         StreamCommonProps("CONTENT_FRAME_TIME", aWriter, aProcessStartTime,
                           aUniqueStacks);
       }
+
+     private:
+      explicit ContentFramePayload(CommonProps&& aCommonProps)
+          : ProfilerMarkerPayload(std::move(aCommonProps)) {}
+      static mozilla::UniquePtr<ProfilerMarkerPayload> Deserialize(
+          mozilla::BlocksRingBuffer::EntryReader& aEntryReader) {
+        ProfilerMarkerPayload::CommonProps props =
+            DeserializeCommonProps(aEntryReader);
+        return UniquePtr<ProfilerMarkerPayload>(
+            new ContentFramePayload(std::move(props)));
+      }
     };
+    AUTO_PROFILER_STATS(add_marker_with_ContentFramePayload);
     profiler_add_marker_for_thread(
         profiler_current_thread_id(), JS::ProfilingCategoryPair::GRAPHICS,
         "CONTENT_FRAME_TIME",
diff --git a/gfx/layers/ipc/ContentCompositorBridgeParent.cpp b/gfx/layers/ipc/ContentCompositorBridgeParent.cpp
index e63dc7b5db..c09c85f653 100644
--- a/gfx/layers/ipc/ContentCompositorBridgeParent.cpp
+++ b/gfx/layers/ipc/ContentCompositorBridgeParent.cpp
@@ -378,19 +378,40 @@ void ContentCompositorBridgeParent::ShadowLayersUpdated(
 
   auto endTime = TimeStamp::Now();
 #ifdef MOZ_GECKO_PROFILER
-  if (profiler_is_active()) {
+  if (profiler_can_accept_markers()) {
     class ContentBuildPayload : public ProfilerMarkerPayload {
      public:
       ContentBuildPayload(const mozilla::TimeStamp& aStartTime,
                           const mozilla::TimeStamp& aEndTime)
           : ProfilerMarkerPayload(aStartTime, aEndTime) {}
-      virtual void StreamPayload(SpliceableJSONWriter& aWriter,
-                                 const TimeStamp& aProcessStartTime,
-                                 UniqueStacks& aUniqueStacks) override {
+      mozilla::BlocksRingBuffer::Length TagAndSerializationBytes()
+          const override {
+        return CommonPropsTagAndSerializationBytes();
+      }
+      void SerializeTagAndPayload(
+          mozilla::BlocksRingBuffer::EntryWriter& aEntryWriter) const override {
+        static const DeserializerTag tag = TagForDeserializer(Deserialize);
+        SerializeTagAndCommonProps(tag, aEntryWriter);
+      }
+      void StreamPayload(SpliceableJSONWriter& aWriter,
+                         const TimeStamp& aProcessStartTime,
+                         UniqueStacks& aUniqueStacks) const override {
         StreamCommonProps("CONTENT_FULL_PAINT_TIME", aWriter, aProcessStartTime,
                           aUniqueStacks);
       }
+
+     private:
+      explicit ContentBuildPayload(CommonProps&& aCommonProps)
+          : ProfilerMarkerPayload(std::move(aCommonProps)) {}
+      static mozilla::UniquePtr<ProfilerMarkerPayload> Deserialize(
+          mozilla::BlocksRingBuffer::EntryReader& aEntryReader) {
+        ProfilerMarkerPayload::CommonProps props =
+            DeserializeCommonProps(aEntryReader);
+        return UniquePtr<ProfilerMarkerPayload>(
+            new ContentBuildPayload(std::move(props)));
+      }
     };
+    AUTO_PROFILER_STATS(add_marker_with_ContentBuildPayload);
     profiler_add_marker_for_thread(
         profiler_current_thread_id(), JS::ProfilingCategoryPair::GRAPHICS,
         "CONTENT_FULL_PAINT_TIME",
diff --git a/gfx/layers/mlgpu/MLGPUScreenshotGrabber.cpp b/gfx/layers/mlgpu/MLGPUScreenshotGrabber.cpp
index 18fe1074bb..1841cdd3bd 100644
--- a/gfx/layers/mlgpu/MLGPUScreenshotGrabber.cpp
+++ b/gfx/layers/mlgpu/MLGPUScreenshotGrabber.cpp
@@ -99,8 +99,8 @@ void MLGPUScreenshotGrabber::MaybeProcessQueue() {
 
 void MLGPUScreenshotGrabber::NotifyEmptyFrame() {
 #ifdef MOZ_GECKO_PROFILER
-  profiler_add_marker("NoCompositorScreenshot because nothing changed",
-                      JS::ProfilingCategoryPair::GRAPHICS);
+  PROFILER_ADD_MARKER("NoCompositorScreenshot because nothing changed",
+                      GRAPHICS);
 #endif
 }
 
diff --git a/gfx/layers/opengl/OGLShaderConfig.h b/gfx/layers/opengl/OGLShaderConfig.h
index 412d2c7b2a..7051d5421a 100644
--- a/gfx/layers/opengl/OGLShaderConfig.h
+++ b/gfx/layers/opengl/OGLShaderConfig.h
@@ -8,7 +8,6 @@
 #include "gfxTypes.h"
 #include "ImageTypes.h"
 #include "mozilla/Assertions.h"  // for MOZ_ASSERT, etc
-#include "mozilla/Pair.h"        // for Pair
 #include "mozilla/RefPtr.h"      // for RefPtr
 #include "mozilla/gfx/Matrix.h"  // for Matrix4x4
 #include "mozilla/gfx/Rect.h"    // for Rect
diff --git a/gfx/layers/opengl/OGLShaderProgram.cpp b/gfx/layers/opengl/OGLShaderProgram.cpp
index 04d6505c84..ed85e906ec 100644
--- a/gfx/layers/opengl/OGLShaderProgram.cpp
+++ b/gfx/layers/opengl/OGLShaderProgram.cpp
@@ -183,7 +183,7 @@ ProgramProfileOGL ProgramProfileOGL::GetProfileFor(ShaderConfigOGL aConfig) {
     vs << "attribute vec2 aCoord;" << endl;
   }
 
-  result.mAttributes.AppendElement(Pair<nsCString, GLuint>{"aCoord", 0});
+  result.mAttributes.AppendElement(std::pair<nsCString, GLuint>{"aCoord", 0});
 
   if (!(aConfig.mFeatures & ENABLE_RENDER_COLOR)) {
     vs << "uniform mat4 uTextureTransform;" << endl;
@@ -192,7 +192,8 @@ ProgramProfileOGL ProgramProfileOGL::GetProfileFor(ShaderConfigOGL aConfig) {
 
     if (aConfig.mFeatures & ENABLE_DYNAMIC_GEOMETRY) {
       vs << "attribute vec2 aTexCoord;" << endl;
-      result.mAttributes.AppendElement(Pair<nsCString, GLuint>{"aTexCoord", 1});
+      result.mAttributes.AppendElement(
+          std::pair<nsCString, GLuint>{"aTexCoord", 1});
     }
   }
 
@@ -930,9 +931,8 @@ bool ShaderProgramOGL::CreateProgram(const char* aVertexShaderString,
   mGL->fAttachShader(result, vertexShader);
   mGL->fAttachShader(result, fragmentShader);
 
-  for (Pair<nsCString, GLuint>& attribute : mProfile.mAttributes) {
-    mGL->fBindAttribLocation(result, attribute.second(),
-                             attribute.first().get());
+  for (std::pair<nsCString, GLuint>& attribute : mProfile.mAttributes) {
+    mGL->fBindAttribLocation(result, attribute.second, attribute.first.get());
   }
 
   mGL->fLinkProgram(result);
diff --git a/gfx/layers/opengl/OGLShaderProgram.h b/gfx/layers/opengl/OGLShaderProgram.h
index ec2c6fe1c6..23de656180 100644
--- a/gfx/layers/opengl/OGLShaderProgram.h
+++ b/gfx/layers/opengl/OGLShaderProgram.h
@@ -9,6 +9,7 @@
 #include "OGLShaderConfig.h"
 
 #include <string>
+#include <utility>
 
 namespace mozilla {
 namespace layers {
@@ -46,7 +47,7 @@ struct ProgramProfileOGL {
   std::string mFragmentShaderString;
 
   // the vertex attributes
-  nsTArray<Pair<nsCString, GLuint>> mAttributes;
+  nsTArray<std::pair<nsCString, GLuint>> mAttributes;
 
   KnownUniform mUniforms[KnownUniform::KnownUniformCount];
   nsTArray<const char*> mDefines;
diff --git a/gfx/layers/wr/IpcResourceUpdateQueue.cpp b/gfx/layers/wr/IpcResourceUpdateQueue.cpp
index 4186c8f271..a09804fc39 100644
--- a/gfx/layers/wr/IpcResourceUpdateQueue.cpp
+++ b/gfx/layers/wr/IpcResourceUpdateQueue.cpp
@@ -70,11 +70,9 @@ layers::OffsetRange ShmSegmentsWriter::Write(Range<uint8_t> aBytes) {
       if (!AllocChunk()) {
         // Allocation failed, so roll back to the state at the start of this
         // Write() call and abort.
-        for (size_t i = mSmallAllocs.Length(); currAllocLen < i; i--) {
-          MOZ_ASSERT(i > 0);
-          RefCountedShmem& shm = mSmallAllocs.ElementAt(i - 1);
+        while (mSmallAllocs.Length() > currAllocLen) {
+          RefCountedShmem shm = mSmallAllocs.PopLastElement();
           RefCountedShm::Dealloc(mShmAllocator, shm);
-          mSmallAllocs.RemoveElementAt(i - 1);
         }
         MOZ_ASSERT(mSmallAllocs.Length() == currAllocLen);
         return layers::OffsetRange(0, start, 0);
@@ -143,8 +141,8 @@ void ShmSegmentsWriter::Flush(nsTArray<RefCountedShmem>& aSmallAllocs,
                               nsTArray<ipc::Shmem>& aLargeAllocs) {
   MOZ_ASSERT(aSmallAllocs.IsEmpty());
   MOZ_ASSERT(aLargeAllocs.IsEmpty());
-  mSmallAllocs.SwapElements(aSmallAllocs);
-  mLargeAllocs.SwapElements(aLargeAllocs);
+  aSmallAllocs = std::move(mSmallAllocs);
+  aLargeAllocs = std::move(mLargeAllocs);
   mCursor = 0;
 }
 
@@ -414,8 +412,7 @@ void IpcResourceUpdateQueue::Flush(
     nsTArray<layers::OpUpdateResource>& aUpdates,
     nsTArray<layers::RefCountedShmem>& aSmallAllocs,
     nsTArray<ipc::Shmem>& aLargeAllocs) {
-  aUpdates.Clear();
-  mUpdates.SwapElements(aUpdates);
+  aUpdates = std::move(mUpdates);
   mWriter.Flush(aSmallAllocs, aLargeAllocs);
 }
 
diff --git a/gfx/layers/wr/WebRenderBridgeParent.cpp b/gfx/layers/wr/WebRenderBridgeParent.cpp
index 18f72e826d..808919da6f 100644
--- a/gfx/layers/wr/WebRenderBridgeParent.cpp
+++ b/gfx/layers/wr/WebRenderBridgeParent.cpp
@@ -67,7 +67,7 @@ void gecko_profiler_add_text_marker(const char* name, const char* text_bytes,
                                     size_t text_len, uint64_t microseconds) {
 #ifdef MOZ_GECKO_PROFILER
   if (profiler_thread_is_being_profiled()) {
-    auto now = mozilla::TimeStamp::Now();
+    auto now = mozilla::TimeStamp::NowUnfuzzed();
     auto start = now - mozilla::TimeDuration::FromMicroseconds(microseconds);
     profiler_add_text_marker(name, nsDependentCSubstring(text_bytes, text_len),
                              JS::ProfilingCategoryPair::GRAPHICS, start, now);
@@ -203,20 +203,43 @@ class SceneBuiltNotification : public wr::NotificationHandler {
         "SceneBuiltNotificationRunnable", [parent, epoch, startTime]() {
           auto endTime = TimeStamp::Now();
 #ifdef MOZ_GECKO_PROFILER
-          if (profiler_is_active()) {
+          if (profiler_can_accept_markers()) {
             class ContentFullPaintPayload : public ProfilerMarkerPayload {
              public:
               ContentFullPaintPayload(const mozilla::TimeStamp& aStartTime,
                                       const mozilla::TimeStamp& aEndTime)
                   : ProfilerMarkerPayload(aStartTime, aEndTime) {}
+              mozilla::BlocksRingBuffer::Length TagAndSerializationBytes()
+                  const override {
+                return CommonPropsTagAndSerializationBytes();
+              }
+              void SerializeTagAndPayload(
+                  mozilla::BlocksRingBuffer::EntryWriter& aEntryWriter)
+                  const override {
+                static const DeserializerTag tag =
+                    TagForDeserializer(Deserialize);
+                SerializeTagAndCommonProps(tag, aEntryWriter);
+              }
               void StreamPayload(SpliceableJSONWriter& aWriter,
                                  const TimeStamp& aProcessStartTime,
-                                 UniqueStacks& aUniqueStacks) override {
+                                 UniqueStacks& aUniqueStacks) const override {
                 StreamCommonProps("CONTENT_FULL_PAINT_TIME", aWriter,
                                   aProcessStartTime, aUniqueStacks);
               }
+
+             private:
+              explicit ContentFullPaintPayload(CommonProps&& aCommonProps)
+                  : ProfilerMarkerPayload(std::move(aCommonProps)) {}
+              static mozilla::UniquePtr<ProfilerMarkerPayload> Deserialize(
+                  mozilla::BlocksRingBuffer::EntryReader& aEntryReader) {
+                ProfilerMarkerPayload::CommonProps props =
+                    DeserializeCommonProps(aEntryReader);
+                return UniquePtr<ProfilerMarkerPayload>(
+                    new ContentFullPaintPayload(std::move(props)));
+              }
             };
 
+            AUTO_PROFILER_STATS(add_marker_with_ContentFullPaintPayload);
             profiler_add_marker_for_thread(
                 profiler_current_thread_id(),
                 JS::ProfilingCategoryPair::GRAPHICS, "CONTENT_FULL_PAINT_TIME",
diff --git a/gfx/layers/wr/WebRenderCommandBuilder.cpp b/gfx/layers/wr/WebRenderCommandBuilder.cpp
index d3514b4d34..7b39a67e40 100644
--- a/gfx/layers/wr/WebRenderCommandBuilder.cpp
+++ b/gfx/layers/wr/WebRenderCommandBuilder.cpp
@@ -304,7 +304,7 @@ struct DIGroup {
   // current item being processed.
   IntRect mClippedImageBounds;  // mLayerBounds with the clipping of any
                                 // containers applied
-  Maybe<mozilla::Pair<wr::RenderRoot, wr::BlobImageKey>> mKey;
+  Maybe<std::pair<wr::RenderRoot, wr::BlobImageKey>> mKey;
   std::vector<RefPtr<ScaledFont>> mFonts;
 
   DIGroup()
@@ -337,7 +337,7 @@ struct DIGroup {
   void ClearImageKey(RenderRootStateManager* aManager, bool aForce = false) {
     if (mKey) {
       MOZ_RELEASE_ASSERT(aForce || mInvalidRect.IsEmpty());
-      aManager->AddBlobImageKeyForDiscard(mKey.value().second());
+      aManager->AddBlobImageKeyForDiscard(mKey.value().second);
       mKey = Nothing();
     }
     mFonts.clear();
@@ -610,7 +610,7 @@ struct DIGroup {
         // so request it be updated unconditionally (wr should be able to easily
         // detect if this is a no-op on its side, if that matters)
         aResources.SetBlobImageVisibleArea(
-            mKey.value().second(),
+            mKey.value().second,
             ViewAs<ImagePixel>(mVisibleRect,
                                PixelCastJustification::LayerIsImage));
         mLastVisibleRect = mVisibleRect;
@@ -698,7 +698,7 @@ struct DIGroup {
                                  PixelCastJustification::LayerIsImage))) {
         return;
       }
-      mKey = Some(MakePair(aBuilder.GetRenderRoot(), key));
+      mKey = Some(std::make_pair(aBuilder.GetRenderRoot(), key));
     } else {
       wr::ImageDescriptor descriptor(dtSize, 0, dt->GetFormat(), opacity);
 
@@ -712,7 +712,7 @@ struct DIGroup {
       GP("Update Blob %d %d %d %d\n", mInvalidRect.x, mInvalidRect.y,
          mInvalidRect.width, mInvalidRect.height);
       if (!aResources.UpdateBlobImage(
-              mKey.value().second(), descriptor, bytes,
+              mKey.value().second, descriptor, bytes,
               ViewAs<ImagePixel>(mVisibleRect,
                                  PixelCastJustification::LayerIsImage),
               dirtyRect)) {
@@ -721,7 +721,7 @@ struct DIGroup {
     }
     mFonts = std::move(fonts);
     aResources.SetBlobImageVisibleArea(
-        mKey.value().second(),
+        mKey.value().second,
         ViewAs<ImagePixel>(mVisibleRect, PixelCastJustification::LayerIsImage));
     mLastVisibleRect = mVisibleRect;
     PushImage(aBuilder, itemBounds);
@@ -749,7 +749,7 @@ struct DIGroup {
     aBuilder.SetHitTestInfo(mScrollId, hitInfo, SideBits::eNone);
     aBuilder.PushImage(dest, dest, !backfaceHidden,
                        wr::ToImageRendering(sampleFilter),
-                       wr::AsImageKey(mKey.value().second()));
+                       wr::AsImageKey(mKey.value().second));
     aBuilder.ClearHitTestInfo();
   }
 
diff --git a/gfx/src/nsRegion.h b/gfx/src/nsRegion.h
index 61cfc07ac1..9bfdcd8c04 100644
--- a/gfx/src/nsRegion.h
+++ b/gfx/src/nsRegion.h
@@ -497,13 +497,12 @@ class nsRegion {
   }
 
   nsRegion(const nsRegion& aRegion) { Copy(aRegion); }
-  nsRegion(nsRegion&& aRegion) {
-    mBands.SwapElements(aRegion.mBands);
-    mBounds = aRegion.mBounds;
+  nsRegion(nsRegion&& aRegion)
+      : mBands(std::move(aRegion.mBands)), mBounds(aRegion.mBounds) {
     aRegion.SetEmpty();
   }
   nsRegion& operator=(nsRegion&& aRegion) {
-    mBands.SwapElements(aRegion.mBands);
+    mBands = std::move(aRegion.mBands);
     mBounds = aRegion.mBounds;
     aRegion.SetEmpty();
     return *this;
diff --git a/gfx/thebes/gfxFontEntry.cpp b/gfx/thebes/gfxFontEntry.cpp
index 1378181493..59493c9348 100644
--- a/gfx/thebes/gfxFontEntry.cpp
+++ b/gfx/thebes/gfxFontEntry.cpp
@@ -1471,10 +1471,9 @@ void gfxFontFamily::FindFontForChar(GlobalFontMatch* aMatchData) {
 
 #ifdef MOZ_GECKO_PROFILER
   nsCString charAndName;
-  if (profiler_is_active()) {
+  if (profiler_can_accept_markers()) {
     charAndName = nsPrintfCString("\\u%x %s", aMatchData->mCh, mName.get());
   }
-
   AUTO_PROFILER_LABEL_DYNAMIC_NSCSTRING("gfxFontFamily::FindFontForChar",
                                         LAYOUT, charAndName);
 #endif
diff --git a/gfx/thebes/gfxSkipChars.h b/gfx/thebes/gfxSkipChars.h
index fc90022885..16ccecbdce 100644
--- a/gfx/thebes/gfxSkipChars.h
+++ b/gfx/thebes/gfxSkipChars.h
@@ -82,7 +82,7 @@ class gfxSkipChars {
   void KeepChar() { KeepChars(1); }
 
   void TakeFrom(gfxSkipChars* aSkipChars) {
-    mRanges.SwapElements(aSkipChars->mRanges);
+    mRanges = std::move(aSkipChars->mRanges);
     mCharCount = aSkipChars->mCharCount;
     aSkipChars->mCharCount = 0;
   }
diff --git a/gfx/thebes/gfxUserFontSet.cpp b/gfx/thebes/gfxUserFontSet.cpp
index 63d222302c..ad0be42ef4 100644
--- a/gfx/thebes/gfxUserFontSet.cpp
+++ b/gfx/thebes/gfxUserFontSet.cpp
@@ -322,7 +322,7 @@ void gfxUserFontEntry::StoreUserFontData(gfxFontEntry* aFontEntry,
   userFontData->mFormat = src.mFormatFlags;
   userFontData->mRealName = aOriginalName;
   if (aMetadata) {
-    userFontData->mMetadata.SwapElements(*aMetadata);
+    userFontData->mMetadata = std::move(*aMetadata);
     userFontData->mMetaOrigLen = aMetaOrigLen;
     userFontData->mCompression = aCompression;
   }
diff --git a/gfx/webrender_bindings/WebRenderAPI.h b/gfx/webrender_bindings/WebRenderAPI.h
index bc9befaaa2..bdcdbe6581 100644
--- a/gfx/webrender_bindings/WebRenderAPI.h
+++ b/gfx/webrender_bindings/WebRenderAPI.h
@@ -665,28 +665,22 @@ class DisplayListBuilder final {
 class MOZ_RAII SpaceAndClipChainHelper final {
  public:
   SpaceAndClipChainHelper(DisplayListBuilder& aBuilder,
-                          wr::WrSpaceAndClipChain aSpaceAndClipChain
-                              MOZ_GUARD_OBJECT_NOTIFIER_PARAM)
+                          wr::WrSpaceAndClipChain aSpaceAndClipChain)
       : mBuilder(aBuilder),
         mOldSpaceAndClipChain(aBuilder.mCurrentSpaceAndClipChain) {
     aBuilder.mCurrentSpaceAndClipChain = aSpaceAndClipChain;
-    MOZ_GUARD_OBJECT_NOTIFIER_INIT;
   }
   SpaceAndClipChainHelper(DisplayListBuilder& aBuilder,
-                          wr::WrSpatialId aSpatialId
-                              MOZ_GUARD_OBJECT_NOTIFIER_PARAM)
+                          wr::WrSpatialId aSpatialId)
       : mBuilder(aBuilder),
         mOldSpaceAndClipChain(aBuilder.mCurrentSpaceAndClipChain) {
     aBuilder.mCurrentSpaceAndClipChain.space = aSpatialId;
-    MOZ_GUARD_OBJECT_NOTIFIER_INIT;
   }
   SpaceAndClipChainHelper(DisplayListBuilder& aBuilder,
-                          wr::WrClipChainId aClipChainId
-                              MOZ_GUARD_OBJECT_NOTIFIER_PARAM)
+                          wr::WrClipChainId aClipChainId)
       : mBuilder(aBuilder),
         mOldSpaceAndClipChain(aBuilder.mCurrentSpaceAndClipChain) {
     aBuilder.mCurrentSpaceAndClipChain.clip_chain = aClipChainId.id;
-    MOZ_GUARD_OBJECT_NOTIFIER_INIT;
   }
 
   ~SpaceAndClipChainHelper() {
@@ -698,7 +692,6 @@ class MOZ_RAII SpaceAndClipChainHelper final {
 
   DisplayListBuilder& mBuilder;
   wr::WrSpaceAndClipChain mOldSpaceAndClipChain;
-  MOZ_DECL_USE_GUARD_OBJECT_NOTIFIER
 };
 
 Maybe<wr::ImageFormat> SurfaceFormatToImageFormat(gfx::SurfaceFormat aFormat);
diff --git a/image/ClippedImage.cpp b/image/ClippedImage.cpp
index 15eea9f3ef..9a11bbac4c 100644
--- a/image/ClippedImage.cpp
+++ b/image/ClippedImage.cpp
@@ -15,7 +15,6 @@
 #include "mozilla/gfx/2D.h"
 #include "mozilla/Move.h"
 #include "mozilla/RefPtr.h"
-#include "mozilla/Pair.h"
 #include "mozilla/Tuple.h"
 
 #include "ImageRegion.h"
@@ -238,13 +237,14 @@ ClippedImage::GetFrameAtSize(const IntSize& aSize, uint32_t aWhichFrame,
   return GetFrame(aWhichFrame, aFlags);
 }
 
-Pair<ImgDrawResult, RefPtr<SourceSurface>> ClippedImage::GetFrameInternal(
+std::pair<ImgDrawResult, RefPtr<SourceSurface>> ClippedImage::GetFrameInternal(
     const nsIntSize& aSize, const Maybe<SVGImageContext>& aSVGContext,
     uint32_t aWhichFrame, uint32_t aFlags, float aOpacity) {
   if (!ShouldClip()) {
     RefPtr<SourceSurface> surface = InnerImage()->GetFrame(aWhichFrame, aFlags);
-    return MakePair(surface ? ImgDrawResult::SUCCESS : ImgDrawResult::NOT_READY,
-                    std::move(surface));
+    return std::make_pair(
+        surface ? ImgDrawResult::SUCCESS : ImgDrawResult::NOT_READY,
+        std::move(surface));
   }
 
   float frameToDraw = InnerImage()->GetFrameIndex(aWhichFrame);
@@ -257,7 +257,8 @@ Pair<ImgDrawResult, RefPtr<SourceSurface>> ClippedImage::GetFrameInternal(
             IntSize(aSize.width, aSize.height), SurfaceFormat::B8G8R8A8);
     if (!target || !target->IsValid()) {
       NS_ERROR("Could not create a DrawTarget");
-      return MakePair(ImgDrawResult::TEMPORARY_ERROR, RefPtr<SourceSurface>());
+      return std::make_pair(ImgDrawResult::TEMPORARY_ERROR,
+                            RefPtr<SourceSurface>());
     }
 
     RefPtr<gfxContext> ctx = gfxContext::CreateOrNull(target);
@@ -284,7 +285,7 @@ Pair<ImgDrawResult, RefPtr<SourceSurface>> ClippedImage::GetFrameInternal(
 
   MOZ_ASSERT(mCachedSurface, "Should have a cached surface now");
   RefPtr<SourceSurface> surface = mCachedSurface->Surface();
-  return MakePair(mCachedSurface->GetDrawResult(), std::move(surface));
+  return std::make_pair(mCachedSurface->GetDrawResult(), std::move(surface));
 }
 
 NS_IMETHODIMP_(bool)
diff --git a/image/ClippedImage.h b/image/ClippedImage.h
index f415d23ee8..52417b04c9 100644
--- a/image/ClippedImage.h
+++ b/image/ClippedImage.h
@@ -11,6 +11,8 @@
 #include "mozilla/RefPtr.h"
 #include "mozilla/UniquePtr.h"
 
+#include <utility>
+
 namespace mozilla {
 namespace image {
 
@@ -74,7 +76,7 @@ class ClippedImage : public ImageWrapper {
   virtual ~ClippedImage();
 
  private:
-  Pair<ImgDrawResult, RefPtr<SourceSurface>> GetFrameInternal(
+  std::pair<ImgDrawResult, RefPtr<SourceSurface>> GetFrameInternal(
       const nsIntSize& aSize, const Maybe<SVGImageContext>& aSVGContext,
       uint32_t aWhichFrame, uint32_t aFlags, float aOpacity);
   bool ShouldClip();
diff --git a/image/SurfaceCache.cpp b/image/SurfaceCache.cpp
index e6c300615a..b29903cac6 100644
--- a/image/SurfaceCache.cpp
+++ b/image/SurfaceCache.cpp
@@ -15,7 +15,6 @@
 #include "mozilla/DebugOnly.h"
 #include "mozilla/Likely.h"
 #include "mozilla/Move.h"
-#include "mozilla/Pair.h"
 #include "mozilla/RefPtr.h"
 #include "mozilla/StaticMutex.h"
 #include "mozilla/StaticPrefs_image.h"
diff --git a/image/test/crashtests/crashtests.list b/image/test/crashtests/crashtests.list
index 2a0b55aa9e..cb693fca63 100644
--- a/image/test/crashtests/crashtests.list
+++ b/image/test/crashtests/crashtests.list
@@ -9,7 +9,7 @@ load 570451.png
 # Bug 1390704 - Skip on debug because it triggers a quadratic behavior that makes it take
 # so much time that it can trip on the reftest timeout of 5 minutes.
 skip-if(Android||isDebugBuild) load 694165-1.xhtml
-load 681190.html
+pref(canvas.mozgetasfile.enabled,true) load 681190.html
 load 732319-1.html
 load 844403-1.html
 load 856616.gif
diff --git a/intl/build/components.conf b/intl/build/components.conf
index f343378662..6afdea6608 100644
--- a/intl/build/components.conf
+++ b/intl/build/components.conf
@@ -4,8 +4,10 @@
 
 Classes = [
     {
+        'js_name': 'strings',
         'cid': '{d85a17c1-aa7c-11d2-9b8c-00805f8a16d9}',
         'contract_ids': ['@mozilla.org/intl/stringbundle;1'],
+        'interfaces': ['nsIStringBundleService'],
         'type': 'nsStringBundleService',
         'headers': ['/intl/strres/nsStringBundleService.h'],
         'init_method': 'Init',
diff --git a/intl/icu/README.md b/intl/icu/README.md
new file mode 100644
index 0000000000..7caf30ceea
--- /dev/null
+++ b/intl/icu/README.md
@@ -0,0 +1,238 @@
+# Introduction
+
+Internationalization (i18n, "i" then 18 letters then "n") is the process of handling data with respect to a particular locale:
+
+* The number 5 representing five US dollars might be formatted as
+  * "$5.00" in American English,
+  * "US$5.00" in Canadian English, or
+  * "5,00 $US" in French.
+* A list of people's names in a phone book would sort
+  * in English alphabetically; but
+  * in German, where "ä"/"ö"/"ü" are often interchangeable with "ae"/"oe"/"ue", alphabetically but with vowels with umlauts treated as their two-vowel counterparts.
+* The currency whose code is "CHF" might be formatted as
+  * "Swiss Franc" in English, but
+  * "franc suisse" in French.
+* The Unix time 1590803313070 might format as the time string
+  * "9:48:33 PM Eastern Daylight Time" in American English, but
+  * "21:48:33 Nordamerikanische Ostküsten-Sommerzeit" in German.
+
+i18n encompasses far more than this, but you get the basic idea.
+
+# Internationalization in SpiderMonkey and Gecko
+
+SpiderMonkey implements extensive i18n capabilities through the [ECMAScript Internationalization API](https://tc39.es/ecma402/) and the global `Intl` object.  Gecko requires i18n capabilities to implement text shaping, sort operations in some contexts, and various other features.
+
+SpiderMonkey and Gecko use [ICU](http://site.icu-project.org/), Internationalization Components for Unicode, to implement many low-level i18n operations.  (Line breaking, implemented instead in `intl/lwbrk`, is a notable exception.)  Gecko and SpiderMonkey also use ICU's implementations of certain i18n-_adjacent_ operations (for example, Unicode normalization).
+
+ICU date/time formatting functionality requires extensive knowledge of time zone names and when zone transitions occur.  The IANA `tzdata` database supplies this information.
+
+A final note of caution: ICU carefully depends upon an exact Unicode version.  Other parts of SpiderMonkey and Gecko have separate dependencies on an exact Unicode version.  Updates to ICU and related components _must_ be synchronized with those updates so that the entirety of SpiderMonkey, and the entirety of Gecko including SpiderMonkey within it, advance to new Unicode versions in lockstep.[^lockstep]
+
+[^lockstep]: The steps involved in updating Gecko-in-general's Unicode version, and updating SpiderMonkey's code dependent on Unicode version, are [documented on WikiMO](https://wiki.mozilla.org/I18n:Updating_Unicode_version).
+
+# Building SpiderMonkey or Gecko with ICU
+
+SpiderMonkey and Gecko can be built using either a periodically-updated copy of ICU in `intl/icu/source` (using time zone data in `intl/tzdata/source`), or using a system-provided ICU library (dependent on its own `tzdata` information).  Pass `--with-system-icu` when configuring to use system ICU.  (Using system ICU will disable some `Intl` functionality, such as historically accurate time zone calculations, that can't be readily supported without a precisely-controlled ICU.)  ICU version requirements advance fairly quickly as Gecko depends on features and bug fixes in newer ICU releases.  You'll get a build error if you try to use an unsupported ICU.
+
+SpiderMonkey's `Intl` API may be built or disabled by configuring `--with-intl-api` (the default) or `--without-intl-api`.  SpiderMonkey built without the `Intl` API doesn't require ICU.  However, if you build without the `Intl` API, some non-`Intl` JavaScript functionality will not exist (`String.prototype.normalize`) or won't fully work (for example, `String.prototype.toLocale{Lower,Upper}Case` will not respect a provided locale, and the various `toLocaleString` functions have best-effort behavior).
+
+# Using ICU functionality in SpiderMonkey and Gecko
+
+ICU headers are considered system headers by the Gecko build system, so they must be listed in `config/system-headers.mozbuild`.  Code that wishes to use ICU functionality may use `#include "unicode/unorm.h"` or similar to do so.
+
+Gecko and SpiderMonkey code may use ICU's stable C API (ICU4C).  These functions are stable and shouldn't change as ICU updates occur.  (ICU4C's `enum` initializers are not always stable: while initializer values are stable, new initializers are sometimes added, perhaps behind `#ifdef U_HIDE_DRAFT_API`.  This may be necessary for exhaustive `switch`es to add `#ifdef`s around some `case`s.)
+
+Gecko and SpiderMonkey are strongly discouraged from using ICU's C++ API (unfortunately including all smart pointer classes), because the C++ API doesn't provide ICU4C's compatibility guarantees.  Rarely, we tolerate C++ API use when no stable option exists.  But the API has to "look" reasonably stable, and we usually want to start a discussion with upstream about adding a stable API to eventually use.  Use symbols from `namespace icu` to access ICU C++ functionality.  _Talk to the current imported-ICU owner (presently Jeff Walden) before you start doing any of this!_
+
+# SpiderMonkey and Gecko's imported ICU
+
+## Build system
+
+The system for building ICU lives in `config/external/icu` and `intl/icu/icu_sources_data.py`.  We generate a Mozilla-compatible build system rather than using ICU's build system.  The build system is shared by SpiderMonkey and Gecko both.
+
+ICU includes functionality we never use, so we don't naively compile all of it.  We extract the list of files to compile from `intl/icu/source/{common,i18n}/Makefile.in` and then apply a manually-maintained blacklist (stored in `intl/icu_sources_data.py`) when we update ICU.
+
+## Locale and time zone data
+
+ICU contains a considerable amount of raw locale data: formatting characteristics for each locale, strings for things like currencies and languages for each locale, localized time zone specifiers, and so on.  This data lives in human-readable files in `intl/icu/source/data`.  Time zone data in `intl/tzdata/source` is stored in partially-compiled formats (some of them only partly human-readable).
+
+However, a normal Gecko build never uses these files!  Instead, both ICU and `tzdata` data are precompiled into a large, endian-specific `icudtNNE.dat` (`NN` = ICU version, `E` = endianness) file.[^why-icudt-not-rebuilt-every-time] That file is added to `config/external/icu/data/` and is checked into the Mozilla tree, to be directly incorporated into Gecko/SpiderMonkey builds.  For size reasons, only the little-endian version is checked into the tree.
+
+ICU's locale data covers _all_ ICU internationalization features, including ones we never need.  We trim locale data to size with a `intl/icu/data_filter.json` [data filter](https://github.com/unicode-org/icu/blob/master/docs/userguide/icu_data/buildtool.md) when compiling `icudtNNE.dat`.  Removing _too much_ data won't _necessarily_ break the build, so it's important that we have automated tests for the locale data we actually use in order to detect mistakes.
+
+[^why-icudt-not-rebuilt-every-time]: `icudtNNE.dat` isn't compiled during a SpiderMonkey/Gecko build because it would require ICU command-line tools.  And it's a pain to either compile and run them during the build, or to require them as build dependencies.
+
+## Local patching of ICU
+
+We generally don't patch our copy of ICU except for compelling need.  When we do patch, we usually only apply reasonably small patches that have been reviewed and landed upstream (so that our patch will be obsolete when we next update ICU).
+
+Local patches are stored in the `intl/icu-patches` directory.  They're applied when ICU is updated, so merely updating ICU files in place won't persist changes across an ICU update.
+
+## Updating imported code
+
+The process of updating imported i18n-relevant code is _semi_-automated.  We use a series of shell and Python scripts to do the job.
+
+### Updating ICU
+
+New ICU versions are announced on the [icu-announce](https://lists.sourceforge.net/lists/listinfo/icu-announce) mailing list.  Both release candidates and actual releases are announced here.  It's a good idea to attempt to update ICU when a release candidate is announced, just in case some serious problem is present (especially one that would be painful to fix through local patching).
+
+`intl/update-icu.sh` updates our ICU to a given ICU release:[^icu-git-argument]
+
+```bash
+$ cd "$topsrcdir/intl"
+$ # Ensure certain Python modules in the tree are accessible when updating.
+$ export PYTHONPATH="$topsrcdir/build/pymake/:$topsrcdir/python/mozbuild/"
+$ #               <URL to ICU Git>                       <release tag name>
+$ ./update-icu.sh https://github.com/unicode-org/icu.git release-67-1
+```
+
+[^icu-git-argument]: The ICU Git URL argument lets you update from a local ICU clone.  This can speed up work when you're updating to a new ICU release and need to adjust or add new local patches.
+
+But usually you'll want to update to the latest commit from the corresponding ICU maintenance branch so that you pick up fixes landed post-release:
+
+```bash
+$ cd "$topsrcdir/intl"
+$ # Ensure certain Python modules in the tree are accessible when updating.
+$ export PYTHONPATH="$topsrcdir/build/pymake/:$topsrcdir/python/mozbuild/"
+$ #               <URL to ICU Git>                       <maintenance name>
+$ ./update-icu.sh https://github.com/unicode-org/icu.git maint/maint-67
+```
+
+Updating ICU will also update the language tag registry (which records language tag semantics needed to correctly implement `Intl` functionality).  Therefore it's likely necessary to update SpiderMonkey's language tag handling after running this[^update-icu-warning-langtags].  See below where the `langtags` mode of `make_intl_data.py` is discussed.
+
+[^update-icu-warning-langtags]: `update-icu.sh` will print a notice as a reminder of this:
+
+    ```bash
+    INFO: Please run 'js/src/builtin/intl/make_intl_data.py langtags' to update additional language tag files for SpiderMonkey.
+    ```
+
+`update-icu.sh` is intended for _replayability_, not for hands-off runnability.  It downloads ICU source, prunes various irrelevant files, replaces `intl/icu/source` with the new files -- and then blindly applies local patches in fixed order.
+
+Often a local patch won't apply, or new patches must be applied to successfully build.  In this case you'll have to manually edit `update-icu.sh` to abort after only _some_ patches have been applied, make whatever changes are necessary by hand, generate a new/updated patch file by hand, then carefully reattempt updating.  (The people who have updated ICU in the past, usually jwalden and anba, follow this awkward process and don't have good ideas on how to improve it.)
+
+Any time ICU is updated, you'll need to fully rebuild whichever of SpiderMonkey or Gecko you're building.  For SpiderMonkey, delete your object directory and reconfigure from scratch.  For Gecko, change the message in the top-level [`CLOBBER`](https://searchfox.org/mozilla-central/source/CLOBBER) file.
+
+### Updating tzdata
+
+ICU contains a copy of `tzdata`, but that copy is whatever `tzdata` release was current at the time the ICU release was finalized.  Time zone data changes much more often than that: every time some national legislature or tinpot dictator decides to alter time zones.[^tzdata-release-frequency]  The [`tz-announce`](https://mm.icann.org/pipermail/tz-announce/) mailing list announces changes as they occur.  (Note that we can't _immediately_ update when a release occurs: ICU's [`icu-data`](https://github.com/unicode-org/icu-data) repository must be updated before we can update our `tzdata`.)
+
+[^tzdata-release-frequency]: To give a sense of how frequently `tzdata` is updated, and the irregularity of releases over time:
+
+    * 2019 had three `tzdata` releases, 2019a through 2019c.
+    * 2018 had nine `tzdata` releases, 2018a through 2018i.
+    * 2017 had three `tzdata` releases, 2017a through 2017c.
+
+Therefore, either (usually) after you update ICU _or_ when a new `tzdata` release occurs, you'll need to update our imported `tzdata` files.  (If you do need to update time zone data, note that you'll also need to additionally update SpiderMonkey's time zone handling, described further below.)  This also suitably updates `config/external/icu/data/icudtNNE.data`.  (If you've just run `update-icu.sh`, it will warn you that you need to do this.[^update-icu-warning-old-tzdata])
+
+[^update-icu-warning-old-tzdata]: For example:
+
+    ```
+    WARN: Local tzdata (2020a) is newer than ICU tzdata (2019c), please run './update-tzdata.sh 2020a'
+    ```
+
+First, make sure you have a usable `icupkg` on your system.[^icupkg-on-system]  Then run the `update-tzdata.sh` script to update `intl/tzdata` and `icudtNNE.data`:
+
+```bash
+$ cd "$topsrcdir/intl"
+$ ./update-tzdata.sh 2020a # or whatever the latest release is
+```
+
+[^icupkg-on-system]: To install `icupkg` on your system:
+
+    * On Fedora, use `sudo dnf install icu`.
+    * On Ubuntu, use `sudo apt-get install icu-devtools`.
+    * On Mac OS X, use `brew install icu4c`.
+    * On Windows, you'll need to [download a binary build of ICU for Windows](https://github.com/unicode-org/icu/releases/tag/release-67-1) and use the `bin/icupkg.exe` or `bin64/icupkg.exe` utility inside it.
+
+    If you're on Windows, or for some reason you don't want to use the `icupkg` now in your `$PATH`, you can manually specify it on the command line using the `-e /path/to/icupkg` flag:
+
+    ```bash
+    $ cd "$topsrcdir/intl"
+    $ ./update-tzdata.sh -e /path/to/icupkg 2020a # or whatever the latest release is
+    ```
+
+    _In principle_, the `icupkg` you use _should_ be the one from the ICU release/maintenance branch being built: if there's a mismatch, you might encounter an ICU "format version not supported" error.  If you're on Windows, make sure to download a binary build for that release/branch.  On other platforms, you might have to build your own ICU from source.  The steps required to do this are left as an exercise for the reader.  (In the somewhat longer term, the update commands might be changed to do this themselves.)
+
+If `tzdata` must be updated on trunk, you'll almost certainly have to backport the update to Beta and ESR.  Don't attempt to backport the literal patch; just run the appropriate commands documented here to do so.
+
+### Updating SpiderMonkey `Intl` data
+
+SpiderMonkey itself can't blindly invoke ICU to perform every i18n operation, because sometimes ICU behavior deviates from what web specifications require.  Therefore, when ICU is updated, we also must update SpiderMonkey itself as well (including various generated tests).  Such updating is performed using the various modes of `js/src/builtin/make_intl_data.py`.
+
+#### Updating SpiderMonkey time zone handling
+
+The ECMAScript Internationalization API requires that time zone identifiers (`America/New_York`, `Antarctica/McMurdo`, etc.) be interpreted according to [`IANA`](https://www.iana.org/time-zones) semantics.  Unfortunately, ICU doesn't precisely implement those semantics.  (See comments in `js/src/builtin/intl/SharedIntlData.h` for details.)  Therefore SpiderMonkey has to do certain pre- and post-processing based on what's in IANA but not in ICU, and what's in ICU that isn't in IANA.
+
+Use `make_intl_data.py`'s `tzdata` mode to update time zone information:
+
+```bash
+$ cd "$topsrcdir/js/src/builtin/intl"
+$ # make_intl_data.py requires yaml.
+$ export PYTHONPATH="$topsrcdir/third_party/python/pyyaml/lib3/"
+$ python3 ./make_intl_data.py tzdata
+```
+
+The `tzdata` mode accepts two optional arguments that generally will not be needed:
+
+* **`--tz`** will act using data from a local `tzdata/` directory containing raw `tzdata` source (note that this is _not_ the same as what is in `intl/tzdata/source`).  It may be useful to help debug problems that arise during an update.
+* **`--ignore-backzone`** will omit time zone information before 1970.  SpiderMonkey and Gecko include this information by default.  However, because (by deliberate policy) `tzdata` information before 1970 is not reliable to the same degree as data since 1970, and backzone data has a size cost, a SpiderMonkey embedding or custom Gecko build might decide to omit it.
+
+#### Updating SpiderMonkey language tag handling
+
+Language tags (`en`, `de-CH`, `ar-u-ca-islamicc`, and so on) are the primary means of specifying localization characteristics.  The ECMAScript Internationalization API supports certain operations that depend upon the current state of the language tag registry (stored in the Unicode Common Locale Data Repository, CLDR, a repository of all locale-specific characteristics) that specifies subtag semantics:
+
+* `Intl.getCanonicalLocales` and `Intl.Locale` must replace alias subtags with their preferred forms.  For example, `ar-u-ca-islamic-civil` uses the preferred Islamic calendar subtag, while `ar-u-ca-islamicc` uses an alias.
+* `Intl.Locale.prototype.maximize` and `Intl.Locale.prototype.minimize` accept a language tag and add or remove "likely" subtags from it.  For example, `de` most likely refers to German using Latin script in Germany, so it maximizes to `de-Latn-DE` -- and in reverse, `de-Latn-DE` minimizes to simply `de`.
+
+These decisions vary over time: as countries change[^soviet-union], as customs change, as language prevalence in regions varies, etc.
+
+[^soviet-union]: For just one relevant example, the breakup of the Soviet Union is the cause of numerous entries in the language tag registry.  `ru-SU`, Russian as used in the Soviet Union, is now expressed as `ru-RU`, Russian as used in Russia; `ab-SU`, Abkhazian as used in the Soviet Union, is now expressed as `ab-GE`, Abkhazian as used in Georgia; and so on for all the other satellite states.
+
+Use `make_intl_data.py`'s `langtags` mode to update language tag information to the same CLDR version used by ICU:
+
+```bash
+$ cd "$topsrcdir/js/src/builtin/intl"
+$ # make_intl_data.py requires yaml.
+$ export PYTHONPATH="$topsrcdir/third_party/python/pyyaml/lib3/"
+$ python3 ./make_intl_data.py langtags
+```
+
+The CLDR version used will be printed in the header of CLDR-sensitive generated files.  For example, `js/src/builtin/intl/LanguageTagGenerated.cpp` currently begins with:
+
+```c++
+// Generated by make_intl_data.py. DO NOT EDIT.
+// Version: CLDR-37
+// URL: https://unicode.org/Public/cldr/37/core.zip
+```
+
+#### Updating SpiderMonkey currency support
+
+Currencies use different numbers of fractional digits in their preferred formatting.  Most currencies use two decimal digits; a handful use no fractional digits or some other number.  Currency fractional digit is maintained by ISO and must be updated as currencies change their preferred fractional digits or new currencies arise that don't use two decimal digits.
+
+Currency updates are fairly uncommon, so it'll be rare to need to update currency info.  A [newsletter](https://www.currency-iso.org/en/home/amendments/newsletter.html) periodically sends updates about changes.
+
+Use `make_intl_data.py`'s `currency` mode to update currency fractional digit information:
+
+```bash
+$ cd "$topsrcdir/js/src/builtin/intl"
+$ # make_intl_data.py requires yaml.
+$ export PYTHONPATH="$topsrcdir/third_party/python/pyyaml/lib3/"
+$ python3 ./make_intl_data.py currency
+```
+
+#### Updating SpiderMonkey measurement formatting support
+
+The `Intl` API supports formatting numbers as measurement units (for example, "17 meters" or "42 meters per second"). It specifies a list of units that must be supported, that we centrally record in `js/src/builtin/intl/SanctionedSimpleUnitIdentifiers.yaml`, that we verify are supported by ICU and generate supporting files from.
+
+If `Intl`'s list of supported units is ever updated, two separate changes will be required.
+
+First, `intl/icu/data_filter.json` must be updated to incorporate localized strings for the new unit.  These strings are stored in `icudtNNE.dat`, so you'll have to re-update ICU (and likely reimport `tzdata` as well, if it's been updated since the last ICU update) to rewrite that file.
+
+Second, use `make_intl_data.py`'s `units` mode to update unit handling and associated tests in SpiderMonkey:
+
+```bash
+$ cd "$topsrcdir/js/src/builtin/intl"
+$ # make_intl_data.py requires yaml.
+$ export PYTHONPATH="$topsrcdir/third_party/python/pyyaml/lib3/"
+$ python3 ./make_intl_data.py units
+```
diff --git a/intl/icu_sources_data.py b/intl/icu_sources_data.py
index 17bf8a19df..ee63cd7f67 100644
--- a/intl/icu_sources_data.py
+++ b/intl/icu_sources_data.py
@@ -83,7 +83,6 @@ UNUSED_SOURCES = sets.Set([
     'intl/icu/source/i18n/translit.cpp',
     'intl/icu/source/i18n/transreg.cpp',
     'intl/icu/source/i18n/tridpars.cpp',
-    'intl/icu/source/i18n/udateintervalformat.cpp',
     'intl/icu/source/i18n/unesctrn.cpp',
     'intl/icu/source/i18n/uni2name.cpp',
     'intl/icu/source/i18n/uregexc.cpp',
diff --git a/intl/l10n/Fluent.jsm b/intl/l10n/Fluent.jsm
index e984b5bfcf..efbf28cd23 100644
--- a/intl/l10n/Fluent.jsm
+++ b/intl/l10n/Fluent.jsm
@@ -14,7 +14,7 @@
  */
 
 
-/* fluent@0.12.0 */
+/* fluent-bundle@0.14.1 */
 
 /* global Intl */
 
@@ -27,15 +27,14 @@
  */
 class FluentType {
   /**
-   * Create an `FluentType` instance.
+   * Create a `FluentType` instance.
    *
-   * @param   {Any}    value - JavaScript value to wrap.
-   * @param   {Object} opts  - Configuration.
+   * @param   {Any} value - JavaScript value to wrap.
    * @returns {FluentType}
    */
-  constructor(value, opts) {
+  constructor(value) {
+    /** The wrapped native value. */
     this.value = value;
-    this.opts = opts;
   }
 
   /**
@@ -51,55 +50,102 @@ class FluentType {
    * Format this instance of `FluentType` to a string.
    *
    * Formatted values are suitable for use outside of the `FluentBundle`.
-   * This method can use `Intl` formatters memoized by the `FluentBundle`
-   * instance passed as an argument.
+   * This method can use `Intl` formatters available through the `scope`
+   * argument.
    *
-   * @param   {FluentBundle} [bundle]
+   * @abstract
+   * @param   {Scope} scope
    * @returns {string}
    */
-  toString() {
+  toString(scope) { // eslint-disable-line no-unused-vars
     throw new Error("Subclasses of FluentType must implement toString.");
   }
 }
 
+/**
+ * A `FluentType` representing no correct value.
+ */
 class FluentNone extends FluentType {
+  /**
+   * Create an instance of `FluentNone` with an optional fallback value.
+   * @param   {string} value - The fallback value of this `FluentNone`.
+   * @returns {FluentType}
+   */
+  constructor(value = "???") {
+    super(value);
+  }
+
+  /**
+   * Format this `FluentNone` to the fallback string.
+   * @returns {string}
+   */
   toString() {
-    return this.value || "???";
+    return `{${this.value}}`;
   }
 }
 
+/**
+ * A `FluentType` representing a number.
+ */
 class FluentNumber extends FluentType {
+  /**
+   * Create an instance of `FluentNumber` with options to the
+   * `Intl.NumberFormat` constructor.
+   * @param   {number} value
+   * @param   {Intl.NumberFormatOptions} opts
+   * @returns {FluentType}
+   */
   constructor(value, opts) {
-    super(parseFloat(value), opts);
+    super(value);
+    /** Options passed to Intl.NumberFormat. */
+    this.opts = opts;
   }
 
-  toString(bundle) {
+  /**
+   * Format this `FluentNumber` to a string.
+   * @param   {Scope} scope
+   * @returns {string}
+   */
+  toString(scope) {
     try {
-      const nf = bundle._memoizeIntlObject(
-        Intl.NumberFormat, this.opts
-      );
+      const nf = scope.memoizeIntlObject(Intl.NumberFormat, this.opts);
       return nf.format(this.value);
-    } catch (e) {
-      // XXX Report the error.
-      return this.value;
+    } catch (err) {
+      scope.reportError(err);
+      return this.value.toString(10);
     }
   }
 }
 
+/**
+ * A `FluentType` representing a date and time.
+ */
 class FluentDateTime extends FluentType {
+  /**
+   * Create an instance of `FluentDateTime` with options to the
+   * `Intl.DateTimeFormat` constructor.
+   * @param   {number} value - timestamp in milliseconds
+   * @param   {Intl.DateTimeFormatOptions} opts
+   * @returns {FluentType}
+   */
   constructor(value, opts) {
-    super(new Date(value), opts);
+    super(value);
+    /** Options passed to Intl.DateTimeFormat. */
+    this.opts = opts;
   }
 
-  toString(bundle) {
+  /**
+   * Format this `FluentDateTime` to a string.
+   * @param   {Scope} scope
+   * @returns {string}
+   */
+  toString(scope) {
     try {
-      const dtf = bundle._memoizeIntlObject(
-        Intl.DateTimeFormat, this.opts
-      );
+      const dtf = scope.memoizeIntlObject(Intl.DateTimeFormat, this.opts);
       return dtf.format(this.value);
-    } catch (e) {
-      // XXX Report the error.
-      return this.value;
+    } catch (err) {
+      scope.reportError(err);
+      return (new Date(this.value)).toISOString();
     }
   }
 }
@@ -117,13 +163,6 @@ class FluentDateTime extends FluentType {
  * `FluentType`.  Functions must return `FluentType` objects as well.
  */
 
-const builtins = {
-  "NUMBER": ([arg], opts) =>
-    new FluentNumber(arg.valueOf(), merge(arg.opts, opts)),
-  "DATETIME": ([arg], opts) =>
-    new FluentDateTime(arg.valueOf(), merge(arg.opts, opts)),
-};
-
 function merge(argopts, opts) {
   return Object.assign({}, argopts, values(opts));
 }
@@ -136,10 +175,44 @@ function values(opts) {
   return unwrapped;
 }
 
+function NUMBER([arg], opts) {
+  if (arg instanceof FluentNone) {
+    return new FluentNone(`NUMBER(${arg.valueOf()})`);
+  }
+
+  let value = Number(arg.valueOf());
+  if (Number.isNaN(value)) {
+    throw new TypeError("Invalid argument to NUMBER");
+  }
+
+  return new FluentNumber(value, merge(arg.opts, opts));
+}
+
+function DATETIME([arg], opts) {
+  if (arg instanceof FluentNone) {
+    return new FluentNone(`DATETIME(${arg.valueOf()})`);
+  }
+
+  let value = Number(arg.valueOf());
+  if (Number.isNaN(value)) {
+    throw new TypeError("Invalid argument to DATETIME");
+  }
+
+  return new FluentDateTime(value, merge(arg.opts, opts));
+}
+
+const builtins = /*#__PURE__*/Object.freeze({
+  __proto__: null,
+  NUMBER: NUMBER,
+  DATETIME: DATETIME
+});
+
 /* global Intl */
 
-// Prevent expansion of too long placeables.
-const MAX_PLACEABLE_LENGTH = 2500;
+// The maximum number of placeables which can be expanded in a single call to
+// `formatPattern`. The limit protects against the Billion Laughs and Quadratic
+// Blowup attacks. See https://msdn.microsoft.com/en-us/magazine/ee335713.aspx.
+const MAX_PLACEABLES = 100;
 
 // Unicode bidi isolation characters.
 const FSI = "\u2068";
@@ -147,7 +220,7 @@ const PDI = "\u2069";
 
 
 // Helper: match a variant key to the given selector.
-function match(bundle, selector, key) {
+function match(scope, selector, key) {
   if (key === selector) {
     // Both are strings.
     return true;
@@ -161,8 +234,8 @@ function match(bundle, selector, key) {
   }
 
   if (selector instanceof FluentNumber && typeof key === "string") {
-    let category = bundle
-      ._memoizeIntlObject(Intl.PluralRules, selector.opts)
+    let category = scope
+      .memoizeIntlObject(Intl.PluralRules, selector.opts)
       .select(selector.value);
     if (key === category) {
       return true;
@@ -175,49 +248,31 @@ function match(bundle, selector, key) {
 // Helper: resolve the default variant from a list of variants.
 function getDefault(scope, variants, star) {
   if (variants[star]) {
-    return Type(scope, variants[star]);
+    return resolvePattern(scope, variants[star].value);
   }
 
-  scope.errors.push(new RangeError("No default"));
+  scope.reportError(new RangeError("No default"));
   return new FluentNone();
 }
 
 // Helper: resolve arguments to a call expression.
 function getArguments(scope, args) {
   const positional = [];
-  const named = {};
+  const named = Object.create(null);
 
   for (const arg of args) {
     if (arg.type === "narg") {
-      named[arg.name] = Type(scope, arg.value);
+      named[arg.name] = resolveExpression(scope, arg.value);
     } else {
-      positional.push(Type(scope, arg));
+      positional.push(resolveExpression(scope, arg));
     }
   }
 
-  return [positional, named];
+  return {positional, named};
 }
 
 // Resolve an expression to a Fluent type.
-function Type(scope, expr) {
-  // A fast-path for strings which are the most common case. Since they
-  // natively have the `toString` method they can be used as if they were
-  // a FluentType instance without incurring the cost of creating one.
-  if (typeof expr === "string") {
-    return scope.bundle._transform(expr);
-  }
-
-  // A fast-path for `FluentNone` which doesn't require any additional logic.
-  if (expr instanceof FluentNone) {
-    return expr;
-  }
-
-  // The Runtime AST (Entries) encodes patterns (complex strings with
-  // placeables) as Arrays.
-  if (Array.isArray(expr)) {
-    return Pattern(scope, expr);
-  }
-
+function resolveExpression(scope, expr) {
   switch (expr.type) {
     case "str":
       return expr.value;
@@ -235,15 +290,6 @@ function Type(scope, expr) {
       return FunctionReference(scope, expr);
     case "select":
       return SelectExpression(scope, expr);
-    case undefined: {
-      // If it's a node with a value, resolve the value.
-      if (expr.value !== null && expr.value !== undefined) {
-        return Type(scope, expr.value);
-      }
-
-      scope.errors.push(new RangeError("No value"));
-      return new FluentNone();
-    }
     default:
       return new FluentNone();
   }
@@ -251,15 +297,26 @@ function Type(scope, expr) {
 
 // Resolve a reference to a variable.
 function VariableReference(scope, {name}) {
-  if (!scope.args || !scope.args.hasOwnProperty(name)) {
-    if (scope.insideTermReference === false) {
-      scope.errors.push(new ReferenceError(`Unknown variable: ${name}`));
+  let arg;
+  if (scope.params) {
+    // We're inside a TermReference. It's OK to reference undefined parameters.
+    if (Object.prototype.hasOwnProperty.call(scope.params, name)) {
+      arg = scope.params[name];
+    } else {
+      return new FluentNone(`$${name}`);
     }
+  } else if (
+    scope.args
+    && Object.prototype.hasOwnProperty.call(scope.args, name)
+  ) {
+    // We're in the top-level Pattern or inside a MessageReference. Missing
+    // variables references produce ReferenceErrors.
+    arg = scope.args[name];
+  } else {
+    scope.reportError(new ReferenceError(`Unknown variable: $${name}`));
     return new FluentNone(`$${name}`);
   }
 
-  const arg = scope.args[name];
-
   // Return early if the argument already is an instance of FluentType.
   if (arg instanceof FluentType) {
     return arg;
@@ -273,11 +330,11 @@ function VariableReference(scope, {name}) {
       return new FluentNumber(arg);
     case "object":
       if (arg instanceof Date) {
-        return new FluentDateTime(arg);
+        return new FluentDateTime(arg.getTime());
       }
     default:
-      scope.errors.push(
-        new TypeError(`Unsupported variable type: ${name}, ${typeof arg}`)
+      scope.reportError(
+        new TypeError(`Variable type not supported: $${name}, ${typeof arg}`)
       );
       return new FluentNone(`$${name}`);
   }
@@ -287,21 +344,25 @@ function VariableReference(scope, {name}) {
 function MessageReference(scope, {name, attr}) {
   const message = scope.bundle._messages.get(name);
   if (!message) {
-    const err = new ReferenceError(`Unknown message: ${name}`);
-    scope.errors.push(err);
+    scope.reportError(new ReferenceError(`Unknown message: ${name}`));
     return new FluentNone(name);
   }
 
   if (attr) {
-    const attribute = message.attrs && message.attrs[attr];
+    const attribute = message.attributes[attr];
     if (attribute) {
-      return Type(scope, attribute);
+      return resolvePattern(scope, attribute);
     }
-    scope.errors.push(new ReferenceError(`Unknown attribute: ${attr}`));
-    return Type(scope, message);
+    scope.reportError(new ReferenceError(`Unknown attribute: ${attr}`));
+    return new FluentNone(`${name}.${attr}`);
   }
 
-  return Type(scope, message);
+  if (message.value) {
+    return resolvePattern(scope, message.value);
+  }
+
+  scope.reportError(new ReferenceError(`No value: ${name}`));
+  return new FluentNone(name);
 }
 
 // Resolve a call to a Term with key-value arguments.
@@ -309,25 +370,27 @@ function TermReference(scope, {name, attr, args}) {
   const id = `-${name}`;
   const term = scope.bundle._terms.get(id);
   if (!term) {
-    const err = new ReferenceError(`Unknown term: ${id}`);
-    scope.errors.push(err);
+    scope.reportError(new ReferenceError(`Unknown term: ${id}`));
     return new FluentNone(id);
   }
 
-  // Every TermReference has its own args.
-  const [, keyargs] = getArguments(scope, args);
-  const local = {...scope, args: keyargs, insideTermReference: true};
-
   if (attr) {
-    const attribute = term.attrs && term.attrs[attr];
+    const attribute = term.attributes[attr];
     if (attribute) {
-      return Type(local, attribute);
+      // Every TermReference has its own variables.
+      scope.params = getArguments(scope, args).named;
+      const resolved = resolvePattern(scope, attribute);
+      scope.params = null;
+      return resolved;
     }
-    scope.errors.push(new ReferenceError(`Unknown attribute: ${attr}`));
-    return Type(local, term);
+    scope.reportError(new ReferenceError(`Unknown attribute: ${attr}`));
+    return new FluentNone(`${id}.${attr}`);
   }
 
-  return Type(local, term);
+  scope.params = getArguments(scope, args).named;
+  const resolved = resolvePattern(scope, term.value);
+  scope.params = null;
+  return resolved;
 }
 
 // Resolve a call to a Function with positional and key-value arguments.
@@ -336,47 +399,46 @@ function FunctionReference(scope, {name, args}) {
   // the `FluentBundle` constructor.
   const func = scope.bundle._functions[name] || builtins[name];
   if (!func) {
-    scope.errors.push(new ReferenceError(`Unknown function: ${name}()`));
+    scope.reportError(new ReferenceError(`Unknown function: ${name}()`));
     return new FluentNone(`${name}()`);
   }
 
   if (typeof func !== "function") {
-    scope.errors.push(new TypeError(`Function ${name}() is not callable`));
+    scope.reportError(new TypeError(`Function ${name}() is not callable`));
     return new FluentNone(`${name}()`);
   }
 
   try {
-    return func(...getArguments(scope, args));
-  } catch (e) {
-    // XXX Report errors.
-    return new FluentNone();
+    let resolved = getArguments(scope, args);
+    return func(resolved.positional, resolved.named);
+  } catch (err) {
+    scope.reportError(err);
+    return new FluentNone(`${name}()`);
   }
 }
 
 // Resolve a select expression to the member object.
 function SelectExpression(scope, {selector, variants, star}) {
-  let sel = Type(scope, selector);
+  let sel = resolveExpression(scope, selector);
   if (sel instanceof FluentNone) {
-    const variant = getDefault(scope, variants, star);
-    return Type(scope, variant);
+    return getDefault(scope, variants, star);
   }
 
   // Match the selector against keys of each variant, in order.
   for (const variant of variants) {
-    const key = Type(scope, variant.key);
-    if (match(scope.bundle, sel, key)) {
-      return Type(scope, variant);
+    const key = resolveExpression(scope, variant.key);
+    if (match(scope, sel, key)) {
+      return resolvePattern(scope, variant.value);
     }
   }
 
-  const variant = getDefault(scope, variants, star);
-  return Type(scope, variant);
+  return getDefault(scope, variants, star);
 }
 
 // Resolve a pattern (a complex string with placeables).
-function Pattern(scope, ptn) {
+function resolveComplexPattern(scope, ptn) {
   if (scope.dirty.has(ptn)) {
-    scope.errors.push(new RangeError("Cyclic reference"));
+    scope.reportError(new RangeError("Cyclic reference"));
     return new FluentNone();
   }
 
@@ -394,23 +456,24 @@ function Pattern(scope, ptn) {
       continue;
     }
 
-    const part = Type(scope, elem).toString(scope.bundle);
+    scope.placeables++;
+    if (scope.placeables > MAX_PLACEABLES) {
+      scope.dirty.delete(ptn);
+      // This is a fatal error which causes the resolver to instantly bail out
+      // on this pattern. The length check protects against excessive memory
+      // usage, and throwing protects against eating up the CPU when long
+      // placeables are deeply nested.
+      throw new RangeError(
+        `Too many placeables expanded: ${scope.placeables}, ` +
+        `max allowed is ${MAX_PLACEABLES}`
+      );
+    }
 
     if (useIsolating) {
       result.push(FSI);
     }
 
-    if (part.length > MAX_PLACEABLE_LENGTH) {
-      scope.errors.push(
-        new RangeError(
-          "Too many characters in placeable " +
-          `(${part.length}, max allowed is ${MAX_PLACEABLE_LENGTH})`
-        )
-      );
-      result.push(part.slice(MAX_PLACEABLE_LENGTH));
-    } else {
-      result.push(part);
-    }
+    result.push(resolveExpression(scope, elem).toString(scope));
 
     if (useIsolating) {
       result.push(PDI);
@@ -421,28 +484,237 @@ function Pattern(scope, ptn) {
   return result.join("");
 }
 
+// Resolve a simple or a complex Pattern to a FluentString (which is really the
+// string primitive).
+function resolvePattern(scope, node) {
+  // Resolve a simple pattern.
+  if (typeof node === "string") {
+    return scope.bundle._transform(node);
+  }
+
+  return resolveComplexPattern(scope, node);
+}
+
+class Scope {
+  constructor(bundle, errors, args) {
+    /** The bundle for which the given resolution is happening. */
+    this.bundle = bundle;
+    /** The list of errors collected while resolving. */
+    this.errors = errors;
+    /** A dict of developer-provided variables. */
+    this.args = args;
+
+    /** The Set of patterns already encountered during this resolution.
+      * Used to detect and prevent cyclic resolutions. */
+    this.dirty = new WeakSet();
+    /** A dict of parameters passed to a TermReference. */
+    this.params = null;
+    /** The running count of placeables resolved so far. Used to detect the
+      * Billion Laughs and Quadratic Blowup attacks. */
+    this.placeables = 0;
+  }
+
+  reportError(error) {
+    if (!this.errors) {
+      throw error;
+    }
+    this.errors.push(error);
+  }
+
+  memoizeIntlObject(ctor, opts) {
+    let cache = this.bundle._intls.get(ctor);
+    if (!cache) {
+      cache = {};
+      this.bundle._intls.set(ctor, cache);
+    }
+    let id = JSON.stringify(opts);
+    if (!cache[id]) {
+      cache[id] = new ctor(this.bundle.locales, opts);
+    }
+    return cache[id];
+  }
+}
+
 /**
- * Format a translation into a string.
- *
- * @param   {FluentBundle} bundle
- *    A FluentBundle instance which will be used to resolve the
- *    contextual information of the message.
- * @param   {Object}         args
- *    List of arguments provided by the developer which can be accessed
- *    from the message.
- * @param   {Object}         message
- *    An object with the Message to be resolved.
- * @param   {Array}          errors
- *    An error array that any encountered errors will be appended to.
- * @returns {FluentType}
+ * Message bundles are single-language stores of translation resources. They are
+ * responsible for formatting message values and attributes to strings.
  */
-function resolve(bundle, args, message, errors = []) {
-  const scope = {
-    bundle, args, errors, dirty: new WeakSet(),
-    // TermReferences are resolved in a new scope.
-    insideTermReference: false,
-  };
-  return Type(scope, message).toString(bundle);
+class FluentBundle {
+  /**
+   * Create an instance of `FluentBundle`.
+   *
+   * The `locales` argument is used to instantiate `Intl` formatters used by
+   * translations. The `options` object can be used to configure the bundle.
+   *
+   * Examples:
+   *
+   *     let bundle = new FluentBundle(["en-US", "en"]);
+   *
+   *     let bundle = new FluentBundle(locales, {useIsolating: false});
+   *
+   *     let bundle = new FluentBundle(locales, {
+   *       useIsolating: true,
+   *       functions: {
+   *         NODE_ENV: () => process.env.NODE_ENV
+   *       }
+   *     });
+   *
+   * Available options:
+   *
+   *   - `functions` - an object of additional functions available to
+   *     translations as builtins.
+   *
+   *   - `useIsolating` - boolean specifying whether to use Unicode isolation
+   *     marks (FSI, PDI) for bidi interpolations. Default: `true`.
+   *
+   *   - `transform` - a function used to transform string parts of patterns.
+   *
+   * @param   {(string|Array.<string>)} locales - The locales of the bundle
+   * @param   {Object} [options]
+   * @returns {FluentBundle}
+   */
+  constructor(locales, {
+    functions = {},
+    useIsolating = true,
+    transform = v => v,
+  } = {}) {
+    this.locales = Array.isArray(locales) ? locales : [locales];
+
+    this._terms = new Map();
+    this._messages = new Map();
+    this._functions = functions;
+    this._useIsolating = useIsolating;
+    this._transform = transform;
+    this._intls = new WeakMap();
+  }
+
+  /**
+   * Check if a message is present in the bundle.
+   *
+   * @param {string} id - The identifier of the message to check.
+   * @returns {bool}
+   */
+  hasMessage(id) {
+    return this._messages.has(id);
+  }
+
+  /**
+   * Return a raw unformatted message object from the bundle.
+   *
+   * Raw messages are `{value, attributes}` shapes containing translation units
+   * called `Patterns`. `Patterns` are implementation-specific; they should be
+   * treated as black boxes and formatted with `FluentBundle.formatPattern`.
+   *
+   *     interface RawMessage {
+   *         value: Pattern | null;
+   *         attributes: Record<string, Pattern>;
+   *     }
+   *
+   * @param {string} id - The identifier of the message to check.
+   * @returns {{value: ?Pattern, attributes: Object.<string, Pattern>}}
+   */
+  getMessage(id) {
+    return this._messages.get(id);
+  }
+
+  /**
+   * Add a translation resource to the bundle.
+   *
+   * The translation resource must be an instance of `FluentResource`.
+   *
+   *     let res = new FluentResource("foo = Foo");
+   *     bundle.addResource(res);
+   *     bundle.getMessage("foo");
+   *     // → {value: .., attributes: {..}}
+   *
+   * Available options:
+   *
+   *   - `allowOverrides` - boolean specifying whether it's allowed to override
+   *     an existing message or term with a new value. Default: `false`.
+   *
+   * @param   {FluentResource} res - FluentResource object.
+   * @param   {Object} [options]
+   * @returns {Array.<FluentError>}
+   */
+  addResource(res, {
+    allowOverrides = false,
+  } = {}) {
+    const errors = [];
+
+    for (let i = 0; i < res.body.length; i++) {
+      let entry = res.body[i];
+      if (entry.id.startsWith("-")) {
+        // Identifiers starting with a dash (-) define terms. Terms are private
+        // and cannot be retrieved from FluentBundle.
+        if (allowOverrides === false && this._terms.has(entry.id)) {
+          errors.push(`Attempt to override an existing term: "${entry.id}"`);
+          continue;
+        }
+        this._terms.set(entry.id, entry);
+      } else {
+        if (allowOverrides === false && this._messages.has(entry.id)) {
+          errors.push(`Attempt to override an existing message: "${entry.id}"`);
+          continue;
+        }
+        this._messages.set(entry.id, entry);
+      }
+    }
+
+    return errors;
+  }
+
+  /**
+   * Format a `Pattern` to a string.
+   *
+   * Format a raw `Pattern` into a string. `args` will be used to resolve
+   * references to variables passed as arguments to the translation.
+   *
+   * In case of errors `formatPattern` will try to salvage as much of the
+   * translation as possible and will still return a string. For performance
+   * reasons, the encountered errors are not returned but instead are appended
+   * to the `errors` array passed as the third argument.
+   *
+   *     let errors = [];
+   *     bundle.addResource(
+   *         new FluentResource("hello = Hello, {$name}!"));
+   *
+   *     let hello = bundle.getMessage("hello");
+   *     if (hello.value) {
+   *         bundle.formatPattern(hello.value, {name: "Jane"}, errors);
+   *         // Returns "Hello, Jane!" and `errors` is empty.
+   *
+   *         bundle.formatPattern(hello.value, undefined, errors);
+   *         // Returns "Hello, {$name}!" and `errors` is now:
+   *         // [<ReferenceError: Unknown variable: name>]
+   *     }
+   *
+   * If `errors` is omitted, the first encountered error will be thrown.
+   *
+   * @param   {Pattern} pattern
+   * @param   {?Object} args
+   * @param   {?Array.<Error>} errors
+   * @returns {string}
+   */
+  formatPattern(pattern, args, errors) {
+    // Resolve a simple pattern without creating a scope. No error handling is
+    // required; by definition simple patterns don't have placeables.
+    if (typeof pattern === "string") {
+      return this._transform(pattern);
+    }
+
+    // Resolve a complex pattern.
+    let scope = new Scope(this, errors, args);
+    try {
+      let value = resolveComplexPattern(scope, pattern);
+      return value.toString(scope);
+    } catch (err) {
+      if (scope.errors) {
+        scope.errors.push(err);
+        return new FluentNone().toString(scope);
+      }
+      throw err;
+    }
+  }
 }
 
 class FluentError extends Error {}
@@ -495,21 +767,18 @@ const TOKEN_COLON = /\s*:\s*/y;
 const TOKEN_COMMA = /\s*,?\s*/y;
 const TOKEN_BLANK = /\s+/y;
 
-// Maximum number of placeables in a single Pattern to protect against Quadratic
-// Blowup attacks. See https://msdn.microsoft.com/en-us/magazine/ee335713.aspx.
-const MAX_PLACEABLES = 100;
-
 /**
- * Fluent Resource is a structure storing a map of parsed localization entries.
+ * Fluent Resource is a structure storing parsed localization entries.
  */
-class FluentResource extends Map {
-  /**
-   * Create a new FluentResource from Fluent code.
-   */
-  static fromString(source) {
+class FluentResource {
+  constructor(source) {
+    this.body = this._parse(source);
+  }
+
+  _parse(source) {
     RE_MESSAGE_START.lastIndex = 0;
 
-    let resource = new this();
+    let resource = [];
     let cursor = 0;
 
     // Iterate over the beginnings of messages and terms to efficiently skip
@@ -522,7 +791,7 @@ class FluentResource extends Map {
 
       cursor = RE_MESSAGE_START.lastIndex;
       try {
-        resource.set(next[1], parseMessage());
+        resource.push(parseMessage(next[1]));
       } catch (err) {
         if (err instanceof FluentError) {
           // Don't report any Fluent syntax errors. Skip directly to the
@@ -535,7 +804,8 @@ class FluentResource extends Map {
 
     return resource;
 
-    // The parser implementation is inlined below for performance reasons.
+    // The parser implementation is inlined below for performance reasons,
+    // as well as for convenience of accessing `source` and `cursor`.
 
     // The parser focuses on minimizing the number of false negatives at the
     // expense of increasing the risk of false positives. In other words, it
@@ -597,22 +867,19 @@ class FluentResource extends Map {
       return match(re)[1];
     }
 
-    function parseMessage() {
+    function parseMessage(id) {
       let value = parsePattern();
-      let attrs = parseAttributes();
+      let attributes = parseAttributes();
 
-      if (attrs === null) {
-        if (value === null) {
-          throw new FluentError("Expected message value or attributes");
-        }
-        return value;
+      if (value === null && Object.keys(attributes).length === 0) {
+        throw new FluentError("Expected message value or attributes");
       }
 
-      return {value, attrs};
+      return {id, value, attributes};
     }
 
     function parseAttributes() {
-      let attrs = {};
+      let attrs = Object.create(null);
 
       while (test(RE_ATTRIBUTE_START)) {
         let name = match1(RE_ATTRIBUTE_START);
@@ -623,7 +890,7 @@ class FluentResource extends Map {
         attrs[name] = value;
       }
 
-      return Object.keys(attrs).length > 0 ? attrs : null;
+      return attrs;
     }
 
     function parsePattern() {
@@ -664,8 +931,6 @@ class FluentResource extends Map {
 
     // Parse a complex pattern as an array of elements.
     function parsePatternElements(elements = [], commonIndent) {
-      let placeableCount = 0;
-
       while (true) {
         if (test(RE_TEXT_RUN)) {
           elements.push(match1(RE_TEXT_RUN));
@@ -673,9 +938,6 @@ class FluentResource extends Map {
         }
 
         if (source[cursor] === "{") {
-          if (++placeableCount > MAX_PLACEABLES) {
-            throw new FluentError("Too many placeables");
-          }
           elements.push(parsePlaceable());
           continue;
         }
@@ -705,9 +967,6 @@ class FluentResource extends Map {
         if (element.type === "indent") {
           // Dedent indented lines by the maximum common indent.
           element = element.value.slice(0, element.value.length - commonIndent);
-        } else if (element.type === "str") {
-          // Optimize StringLiterals into their value.
-          element = element.value;
         }
         if (element) {
           baked.push(element);
@@ -837,7 +1096,7 @@ class FluentResource extends Map {
       consumeToken(TOKEN_BRACKET_OPEN, FluentError);
       let key = test(RE_NUMBER_LITERAL)
         ? parseNumberLiteral()
-        : match1(RE_IDENTIFIER);
+        : {type: "str", value: match1(RE_IDENTIFIER)};
       consumeToken(TOKEN_BRACKET_CLOSE, FluentError);
       return key;
     }
@@ -949,267 +1208,6 @@ class FluentResource extends Map {
   }
 }
 
-/**
- * Message bundles are single-language stores of translations.  They are
- * responsible for parsing translation resources in the Fluent syntax and can
- * format translation units (entities) to strings.
- *
- * Always use `FluentBundle.format` to retrieve translation units from a
- * bundle. Translations can contain references to other entities or variables,
- * conditional logic in form of select expressions, traits which describe their
- * grammatical features, and can use Fluent builtins which make use of the
- * `Intl` formatters to format numbers, dates, lists and more into the
- * bundle's language. See the documentation of the Fluent syntax for more
- * information.
- */
-class FluentBundle {
-  /**
-   * Create an instance of `FluentBundle`.
-   *
-   * The `locales` argument is used to instantiate `Intl` formatters used by
-   * translations.  The `options` object can be used to configure the bundle.
-   *
-   * Examples:
-   *
-   *     const bundle = new FluentBundle(locales);
-   *
-   *     const bundle = new FluentBundle(locales, { useIsolating: false });
-   *
-   *     const bundle = new FluentBundle(locales, {
-   *       useIsolating: true,
-   *       functions: {
-   *         NODE_ENV: () => process.env.NODE_ENV
-   *       }
-   *     });
-   *
-   * Available options:
-   *
-   *   - `functions` - an object of additional functions available to
-   *                   translations as builtins.
-   *
-   *   - `useIsolating` - boolean specifying whether to use Unicode isolation
-   *                    marks (FSI, PDI) for bidi interpolations.
-   *                    Default: true
-   *
-   *   - `transform` - a function used to transform string parts of patterns.
-   *
-   * @param   {string|Array<string>} locales - Locale or locales of the bundle
-   * @param   {Object} [options]
-   * @returns {FluentBundle}
-   */
-  constructor(locales, {
-    functions = {},
-    useIsolating = true,
-    transform = v => v,
-  } = {}) {
-    this.locales = Array.isArray(locales) ? locales : [locales];
-
-    this._terms = new Map();
-    this._messages = new Map();
-    this._functions = functions;
-    this._useIsolating = useIsolating;
-    this._transform = transform;
-    this._intls = new WeakMap();
-  }
-
-  /*
-   * Return an iterator over public `[id, message]` pairs.
-   *
-   * @returns {Iterator}
-   */
-  get messages() {
-    return this._messages[Symbol.iterator]();
-  }
-
-  /*
-   * Check if a message is present in the bundle.
-   *
-   * @param {string} id - The identifier of the message to check.
-   * @returns {bool}
-   */
-  hasMessage(id) {
-    return this._messages.has(id);
-  }
-
-  /*
-   * Return the internal representation of a message.
-   *
-   * The internal representation should only be used as an argument to
-   * `FluentBundle.format`.
-   *
-   * @param {string} id - The identifier of the message to check.
-   * @returns {Any}
-   */
-  getMessage(id) {
-    return this._messages.get(id);
-  }
-
-  /**
-   * Add a translation resource to the bundle.
-   *
-   * The translation resource must use the Fluent syntax.  It will be parsed by
-   * the bundle and each translation unit (message) will be available in the
-   * bundle by its identifier.
-   *
-   *     bundle.addMessages('foo = Foo');
-   *     bundle.getMessage('foo');
-   *
-   *     // Returns a raw representation of the 'foo' message.
-   *
-   *     bundle.addMessages('bar = Bar');
-   *     bundle.addMessages('bar = Newbar', { allowOverrides: true });
-   *     bundle.getMessage('bar');
-   *
-   *     // Returns a raw representation of the 'bar' message: Newbar.
-   *
-   * Parsed entities should be formatted with the `format` method in case they
-   * contain logic (references, select expressions etc.).
-   *
-   * Available options:
-   *
-   *   - `allowOverrides` - boolean specifying whether it's allowed to override
-   *                      an existing message or term with a new value.
-   *                      Default: false
-   *
-   * @param   {string} source - Text resource with translations.
-   * @param   {Object} [options]
-   * @returns {Array<Error>}
-   */
-  addMessages(source, options) {
-    const res = FluentResource.fromString(source);
-    return this.addResource(res, options);
-  }
-
-  /**
-   * Add a translation resource to the bundle.
-   *
-   * The translation resource must be an instance of FluentResource,
-   * e.g. parsed by `FluentResource.fromString`.
-   *
-   *     let res = FluentResource.fromString("foo = Foo");
-   *     bundle.addResource(res);
-   *     bundle.getMessage('foo');
-   *
-   *     // Returns a raw representation of the 'foo' message.
-   *
-   *     let res = FluentResource.fromString("bar = Bar");
-   *     bundle.addResource(res);
-   *     res = FluentResource.fromString("bar = Newbar");
-   *     bundle.addResource(res, { allowOverrides: true });
-   *     bundle.getMessage('bar');
-   *
-   *     // Returns a raw representation of the 'bar' message: Newbar.
-   *
-   * Parsed entities should be formatted with the `format` method in case they
-   * contain logic (references, select expressions etc.).
-   *
-   * Available options:
-   *
-   *   - `allowOverrides` - boolean specifying whether it's allowed to override
-   *                      an existing message or term with a new value.
-   *                      Default: false
-   *
-   * @param   {FluentResource} res - FluentResource object.
-   * @param   {Object} [options]
-   * @returns {Array<Error>}
-   */
-  addResource(res, {
-    allowOverrides = false,
-  } = {}) {
-    const errors = [];
-
-    for (const [id, value] of res) {
-      if (id.startsWith("-")) {
-        // Identifiers starting with a dash (-) define terms. Terms are private
-        // and cannot be retrieved from FluentBundle.
-        if (allowOverrides === false && this._terms.has(id)) {
-          errors.push(`Attempt to override an existing term: "${id}"`);
-          continue;
-        }
-        this._terms.set(id, value);
-      } else {
-        if (allowOverrides === false && this._messages.has(id)) {
-          errors.push(`Attempt to override an existing message: "${id}"`);
-          continue;
-        }
-        this._messages.set(id, value);
-      }
-    }
-
-    return errors;
-  }
-
-  /**
-   * Format a message to a string or null.
-   *
-   * Format a raw `message` from the bundle into a string (or a null if it has
-   * a null value).  `args` will be used to resolve references to variables
-   * passed as arguments to the translation.
-   *
-   * In case of errors `format` will try to salvage as much of the translation
-   * as possible and will still return a string.  For performance reasons, the
-   * encountered errors are not returned but instead are appended to the
-   * `errors` array passed as the third argument.
-   *
-   *     const errors = [];
-   *     bundle.addMessages('hello = Hello, { $name }!');
-   *     const hello = bundle.getMessage('hello');
-   *     bundle.format(hello, { name: 'Jane' }, errors);
-   *
-   *     // Returns 'Hello, Jane!' and `errors` is empty.
-   *
-   *     bundle.format(hello, undefined, errors);
-   *
-   *     // Returns 'Hello, name!' and `errors` is now:
-   *
-   *     [<ReferenceError: Unknown variable: name>]
-   *
-   * @param   {Object | string}    message
-   * @param   {Object | undefined} args
-   * @param   {Array}              errors
-   * @returns {?string}
-   */
-  format(message, args, errors) {
-    // optimize entities which are simple strings with no attributes
-    if (typeof message === "string") {
-      return this._transform(message);
-    }
-
-    // optimize entities with null values
-    if (message === null || message.value === null) {
-      return null;
-    }
-
-    // optimize simple-string entities with attributes
-    if (typeof message.value === "string") {
-      return this._transform(message.value);
-    }
-
-    return resolve(this, args, message, errors);
-  }
-
-  _memoizeIntlObject(ctor, opts) {
-    const cache = this._intls.get(ctor) || {};
-    const id = JSON.stringify(opts);
-
-    if (!cache[id]) {
-      cache[id] = new ctor(this.locales, opts);
-      this._intls.set(ctor, cache);
-    }
-
-    return cache[id];
-  }
-}
-
-/*
- * @module fluent
- * @overview
- *
- * `fluent` is a JavaScript implementation of Project Fluent, a localization
- * framework designed to unleash the expressive power of the natural language.
- *
- */
-
 this.EXPORTED_SYMBOLS = [
   ...Object.keys({
     FluentBundle,
diff --git a/intl/l10n/L10nRegistry.jsm b/intl/l10n/L10nRegistry.jsm
index 9d469072a7..e77f4c86f8 100644
--- a/intl/l10n/L10nRegistry.jsm
+++ b/intl/l10n/L10nRegistry.jsm
@@ -654,7 +654,7 @@ class FileSource {
       if (data === false) {
         this.cache[fullPath] = false;
       } else {
-        this.cache[fullPath] = FluentResource.fromString(data);
+        this.cache[fullPath] = new FluentResource(data);
       }
 
       return this.cache[fullPath];
@@ -663,7 +663,7 @@ class FileSource {
     // async
     return this.cache[fullPath] = L10nRegistry.load(fullPath).then(
       data => {
-        return this.cache[fullPath] = FluentResource.fromString(data);
+        return this.cache[fullPath] = new FluentResource(data);
       },
       err => {
         this.cache[fullPath] = false;
diff --git a/intl/l10n/Localization.jsm b/intl/l10n/Localization.jsm
index 2000f8a61f..bf4de032e3 100644
--- a/intl/l10n/Localization.jsm
+++ b/intl/l10n/Localization.jsm
@@ -329,9 +329,9 @@ class Localization {
   /**
    * Format translations into {value, attributes} objects.
    *
-   * The fallback logic is the same as in `formatValues` but the argument type
-   * is stricter (an array of arrays) and it returns {value, attributes}
-   * objects which are suitable for the translation of DOM elements.
+   * The fallback logic is the same as in `formatValues` but it returns {value,
+   * attributes} objects which are suitable for the translation of DOM
+   * elements.
    *
    *     docL10n.formatMessages([
    *       {id: 'hello', args: { who: 'Mary' }},
@@ -372,8 +372,8 @@ class Localization {
   /**
    * Retrieve translations corresponding to the passed keys.
    *
-   * A generalized version of `Localization.formatValue`. Keys can
-   * either be simple string identifiers or `[id, args]` arrays.
+   * A generalized version of `Localization.formatValue`. Keys must
+   * be `{id, args}` objects.
    *
    *     docL10n.formatValues([
    *       {id: 'hello', args: { who: 'Mary' }},
@@ -510,26 +510,26 @@ Localization.prototype.QueryInterface = ChromeUtils.generateQI([
 ]);
 
 /**
- * Format the value of a message into a string.
+ * Format the value of a message into a string or `null`.
  *
  * This function is passed as a method to `keysFromBundle` and resolve
  * a value of a single L10n Entity using provided `FluentBundle`.
- *
- * If the function fails to retrieve the entity, it will return an ID of it.
- * If formatting fails, it will return a partially resolved entity.
- *
- * In both cases, an error is being added to the errors array.
+
+ * If the message doesn't have a value, return `null`.
  *
  * @param   {FluentBundle} bundle
- * @param   {Array<Error>}   errors
- * @param   {string}         id
- * @param   {Object}         args
- * @returns {string}
+ * @param   {Array<Error>} errors
+ * @param   {Object} message
+ * @param   {Object} args
+ * @returns {string|null}
  * @private
  */
-function valueFromBundle(bundle, errors, id, args) {
-  const msg = bundle.getMessage(id);
-  return bundle.format(msg, args, errors);
+function valueFromBundle(bundle, errors, message, args) {
+  if (message.value) {
+    return bundle.formatPattern(message.value, args, errors);
+  }
+
+  return null;
 }
 
 /**
@@ -541,34 +541,29 @@ function valueFromBundle(bundle, errors, id, args) {
  * The function will return an object with a value and attributes of the
  * entity.
  *
- * If the function fails to retrieve the entity, the value is set to the ID of
- * an entity, and attributes to `null`. If formatting fails, it will return
- * a partially resolved value and attributes.
- *
- * In both cases, an error is being added to the errors array.
- *
  * @param   {FluentBundle} bundle
  * @param   {Array<Error>}   errors
- * @param   {String}         id
- * @param   {Object}         args
+ * @param   {Object} message
+ * @param   {Object} args
  * @returns {Object}
  * @private
  */
-function messageFromBundle(bundle, errors, id, args) {
-  const msg = bundle.getMessage(id);
-
+function messageFromBundle(bundle, errors, message, args) {
   const formatted = {
-    value: bundle.format(msg, args, errors),
+    value: null,
     attributes: null,
   };
 
-  if (msg.attrs) {
-    formatted.attributes = [];
-    for (const [name, attr] of Object.entries(msg.attrs)) {
-      const value = bundle.format(attr, args, errors);
-      if (value !== null) {
-        formatted.attributes.push({name, value});
-      }
+  if (message.value) {
+    formatted.value = bundle.formatPattern(message.value, args, errors);
+  }
+
+  let attrNames = Object.keys(message.attributes);
+  if (attrNames.length > 0) {
+    formatted.attributes = new Array(attrNames.length);
+    for (let [i, name] of attrNames.entries()) {
+      let value = bundle.formatPattern(message.attributes[name], args, errors);
+      formatted.attributes[i] = {name, value};
     }
   }
 
@@ -616,9 +611,10 @@ function keysFromBundle(method, bundle, keys, translations) {
       return;
     }
 
-    if (bundle.hasMessage(id)) {
+    let message = bundle.getMessage(id);
+    if (message) {
       messageErrors.length = 0;
-      translations[i] = method(bundle, messageErrors, id, args);
+      translations[i] = method(bundle, messageErrors, message, args);
       if (messageErrors.length > 0) {
         const locale = bundle.locales[0];
         const errors = messageErrors.join(", ");
diff --git a/intl/l10n/test/mochitest/localization/test_formatMessages.html b/intl/l10n/test/mochitest/localization/test_formatMessages.html
index c069c32b2b..b6a368ad79 100644
--- a/intl/l10n/test/mochitest/localization/test_formatMessages.html
+++ b/intl/l10n/test/mochitest/localization/test_formatMessages.html
@@ -7,20 +7,20 @@
   <link rel="stylesheet" type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css">
   <script type="application/javascript">
   "use strict";
-  const { FluentBundle } =
+  const { FluentBundle, FluentResource } =
     ChromeUtils.import("resource://gre/modules/Fluent.jsm");
 
-  async function* mockGenerateMessages(locales, resourceIds) {
-    const bundle = new FluentBundle(locales, {
+  async function* mockGenerateMessages(resourceIds) {
+    const bundle = new FluentBundle("en-US", {
       useIsolating: false,
     });
-    bundle.addMessages(`
+    bundle.addResource(new FluentResource(`
 key1 = Value
   .title = Title 1
   .accesskey = K
 key2 =
   .label = This is a label for { $user }
-    `);
+    `));
     yield bundle;
   }
 
@@ -59,7 +59,7 @@ key2 =
         ok(false, "Missing argument didn't cause an exception.");
       } catch (e) {
         is(e,
-          "[fluent][resolver] errors in mock.ftl/key2: ReferenceError: Unknown variable: user.",
+          "[fluent][resolver] errors in en-US/key2: ReferenceError: Unknown variable: $user.",
           "Missing key causes an exception.");
       }
     }
@@ -74,7 +74,7 @@ key2 =
         ok(false, "Missing key didn't cause an exception.");
       } catch (e) {
         is(e,
-           "[fluent] Missing translations in mock.ftl: key4.",
+           "[fluent] Missing translations in en-US: key4.",
            "Missing key causes an exception.");
       }
     }
@@ -84,4 +84,4 @@ key2 =
 </head>
 <body>
 </body>
-</html>
\ No newline at end of file
+</html>
diff --git a/intl/l10n/test/mochitest/localization/test_formatValue.html b/intl/l10n/test/mochitest/localization/test_formatValue.html
index 3828307ba2..302694b669 100644
--- a/intl/l10n/test/mochitest/localization/test_formatValue.html
+++ b/intl/l10n/test/mochitest/localization/test_formatValue.html
@@ -7,18 +7,18 @@
   <link rel="stylesheet" type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css">
   <script type="application/javascript">
   "use strict";
-  const { FluentBundle } =
+  const { FluentBundle, FluentResource } =
     ChromeUtils.import("resource://gre/modules/Fluent.jsm");
 
-  async function* mockGenerateMessages(locales, resourceIds) {
-    const bundle = new FluentBundle(locales, {
+  async function* mockGenerateMessages(resourceIds) {
+    const bundle = new FluentBundle("en-US", {
       useIsolating: false,
     });
-    bundle.addMessages(`
+    bundle.addResource(new FluentResource(`
 key1 = Value
 key2 = Value { $user }
 key3 = Value { $count }
-    `);
+    `));
     yield bundle;
   }
 
@@ -56,7 +56,7 @@ key3 = Value { $count }
         ok(false, "Missing argument didn't cause an exception.");
       } catch (e) {
         is(e,
-          "[fluent][resolver] errors in mock.ftl/key3: ReferenceError: Unknown variable: count.",
+          "[fluent][resolver] errors in en-US/key3: ReferenceError: Unknown variable: $count.",
           "Missing key causes an exception.");
       }
     }
@@ -75,4 +75,4 @@ key3 = Value { $count }
 </head>
 <body>
 </body>
-</html>
\ No newline at end of file
+</html>
diff --git a/intl/l10n/test/mochitest/localization/test_formatValues.html b/intl/l10n/test/mochitest/localization/test_formatValues.html
index 635edb573d..a71d380126 100644
--- a/intl/l10n/test/mochitest/localization/test_formatValues.html
+++ b/intl/l10n/test/mochitest/localization/test_formatValues.html
@@ -7,19 +7,19 @@
   <link rel="stylesheet" type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css">
   <script type="application/javascript">
   "use strict";
-  const { FluentBundle } =
+  const { FluentBundle, FluentResource } =
     ChromeUtils.import("resource://gre/modules/Fluent.jsm");
 
-  async function* mockGenerateMessages(locales, resourceIds) {
-    const bundle = new FluentBundle(locales,
+  async function* mockGenerateMessages(resourceIds) {
+    const bundle = new FluentBundle("en-US",
     {
       useIsolating: false,
     });
-    bundle.addMessages(`
+    bundle.addResource(new FluentResource(`
 key1 = Value
 key2 = Value { $user }
 key3 = Value { $count }
-    `);
+    `));
     yield bundle;
   }
 
@@ -54,7 +54,7 @@ key3 = Value { $count }
         ok(false, "Missing argument didn't cause an exception.");
       } catch (e) {
         is(e,
-          "[fluent][resolver] errors in mock.ftl/key2: ReferenceError: Unknown variable: user.",
+          "[fluent][resolver] errors in en-US/key2: ReferenceError: Unknown variable: $user.",
           "Missing key causes an exception.");
       }
     }
@@ -69,7 +69,7 @@ key3 = Value { $count }
         ok(false, "Missing key didn't cause an exception.");
       } catch (e) {
         is(e,
-           "[fluent] Missing translations in mock.ftl: key4.",
+           "[fluent] Missing translations in en-US: key4.",
            "Missing key causes an exception.");
       }
     }
@@ -80,4 +80,4 @@ key3 = Value { $count }
 </head>
 <body>
 </body>
-</html>
\ No newline at end of file
+</html>
diff --git a/intl/l10n/test/test_l10nregistry.js b/intl/l10n/test/test_l10nregistry.js
index 7286c73243..c219019f4f 100644
--- a/intl/l10n/test/test_l10nregistry.js
+++ b/intl/l10n/test/test_l10nregistry.js
@@ -147,7 +147,7 @@ add_task(async function test_has_two_sources() {
 
   equal(bundle0.hasMessage("key"), true);
   let msg = bundle0.getMessage("key");
-  equal(bundle0.format(msg), "platform value");
+  equal(bundle0.formatPattern(msg.value), "platform value");
 
   equal((await bundles.next()).done, true);
 
@@ -159,13 +159,13 @@ add_task(async function test_has_two_sources() {
   equal(bundle0.locales[0], "pl");
   equal(bundle0.hasMessage("key"), true);
   let msg0 = bundle0.getMessage("key");
-  equal(bundle0.format(msg0), "app value");
+  equal(bundle0.formatPattern(msg0.value), "app value");
 
   let bundle1 = (await bundles.next()).value;
   equal(bundle1.locales[0], "en-US");
   equal(bundle1.hasMessage("key"), true);
   let msg1 = bundle1.getMessage("key");
-  equal(bundle1.format(msg1), "platform value");
+  equal(bundle1.formatPattern(msg1.value), "platform value");
 
   equal((await bundles.next()).done, true);
 
@@ -226,13 +226,13 @@ add_task(async function test_override() {
   equal(bundle0.locales[0], "pl");
   equal(bundle0.hasMessage("key"), true);
   let msg0 = bundle0.getMessage("key");
-  equal(bundle0.format(msg0), "addon value");
+  equal(bundle0.formatPattern(msg0.value), "addon value");
 
   let bundle1 = (await bundles.next()).value;
   equal(bundle1.locales[0], "pl");
   equal(bundle1.hasMessage("key"), true);
   let msg1 = bundle1.getMessage("key");
-  equal(bundle1.format(msg1), "value");
+  equal(bundle1.formatPattern(msg1.value), "value");
 
   equal((await bundles.next()).done, true);
 
@@ -258,7 +258,7 @@ add_task(async function test_updating() {
   equal(bundle0.locales[0], "pl");
   equal(bundle0.hasMessage("key"), true);
   let msg0 = bundle0.getMessage("key");
-  equal(bundle0.format(msg0), "value");
+  equal(bundle0.formatPattern(msg0.value), "value");
 
 
   const newSource = new IndexedFileSource("langpack-pl", ["pl"], "/data/locales/{locale}/", [
@@ -271,7 +271,7 @@ add_task(async function test_updating() {
   bundles = L10nRegistry.generateBundles(["pl"], ["test.ftl"]);
   bundle0 = (await bundles.next()).value;
   msg0 = bundle0.getMessage("key");
-  equal(bundle0.format(msg0), "new value");
+  equal(bundle0.formatPattern(msg0.value), "new value");
 
   // cleanup
   L10nRegistry.sources.clear();
@@ -303,13 +303,13 @@ add_task(async function test_removing() {
   equal(bundle0.locales[0], "pl");
   equal(bundle0.hasMessage("key"), true);
   let msg0 = bundle0.getMessage("key");
-  equal(bundle0.format(msg0), "addon value");
+  equal(bundle0.formatPattern(msg0.value), "addon value");
 
   let bundle1 = (await bundles.next()).value;
   equal(bundle1.locales[0], "pl");
   equal(bundle1.hasMessage("key"), true);
   let msg1 = bundle1.getMessage("key");
-  equal(bundle1.format(msg1), "value");
+  equal(bundle1.formatPattern(msg1.value), "value");
 
   equal((await bundles.next()).done, true);
 
@@ -325,7 +325,7 @@ add_task(async function test_removing() {
   equal(bundle0.locales[0], "pl");
   equal(bundle0.hasMessage("key"), true);
   msg0 = bundle0.getMessage("key");
-  equal(bundle0.format(msg0), "value");
+  equal(bundle0.formatPattern(msg0.value), "value");
 
   equal((await bundles.next()).done, true);
 
diff --git a/intl/l10n/test/test_l10nregistry_sync.js b/intl/l10n/test/test_l10nregistry_sync.js
index 5e398e7d2c..e3146eae35 100644
--- a/intl/l10n/test/test_l10nregistry_sync.js
+++ b/intl/l10n/test/test_l10nregistry_sync.js
@@ -148,7 +148,7 @@ add_task(function test_has_two_sources() {
 
   equal(bundle0.hasMessage("key"), true);
   let msg = bundle0.getMessage("key");
-  equal(bundle0.format(msg), "platform value");
+  equal(bundle0.formatPattern(msg.value), "platform value");
 
   equal((bundles.next()).done, true);
 
@@ -160,13 +160,13 @@ add_task(function test_has_two_sources() {
   equal(bundle0.locales[0], "pl");
   equal(bundle0.hasMessage("key"), true);
   let msg0 = bundle0.getMessage("key");
-  equal(bundle0.format(msg0), "app value");
+  equal(bundle0.formatPattern(msg0.value), "app value");
 
   let bundle1 = (bundles.next()).value;
   equal(bundle1.locales[0], "en-US");
   equal(bundle1.hasMessage("key"), true);
   let msg1 = bundle1.getMessage("key");
-  equal(bundle1.format(msg1), "platform value");
+  equal(bundle1.formatPattern(msg1.value), "platform value");
 
   equal((bundles.next()).done, true);
 
@@ -227,13 +227,13 @@ add_task(function test_override() {
   equal(bundle0.locales[0], "pl");
   equal(bundle0.hasMessage("key"), true);
   let msg0 = bundle0.getMessage("key");
-  equal(bundle0.format(msg0), "addon value");
+  equal(bundle0.formatPattern(msg0.value), "addon value");
 
   let bundle1 = (bundles.next()).value;
   equal(bundle1.locales[0], "pl");
   equal(bundle1.hasMessage("key"), true);
   let msg1 = bundle1.getMessage("key");
-  equal(bundle1.format(msg1), "value");
+  equal(bundle1.formatPattern(msg1.value), "value");
 
   equal((bundles.next()).done, true);
 
@@ -259,7 +259,7 @@ add_task(function test_updating() {
   equal(bundle0.locales[0], "pl");
   equal(bundle0.hasMessage("key"), true);
   let msg0 = bundle0.getMessage("key");
-  equal(bundle0.format(msg0), "value");
+  equal(bundle0.formatPattern(msg0.value), "value");
 
 
   const newSource = new IndexedFileSource("langpack-pl", ["pl"], "/data/locales/{locale}/", [
@@ -272,7 +272,7 @@ add_task(function test_updating() {
   bundles = L10nRegistry.generateBundlesSync(["pl"], ["test.ftl"]);
   bundle0 = (bundles.next()).value;
   msg0 = bundle0.getMessage("key");
-  equal(bundle0.format(msg0), "new value");
+  equal(bundle0.formatPattern(msg0.value), "new value");
 
   // cleanup
   L10nRegistry.sources.clear();
@@ -304,13 +304,13 @@ add_task(function test_removing() {
   equal(bundle0.locales[0], "pl");
   equal(bundle0.hasMessage("key"), true);
   let msg0 = bundle0.getMessage("key");
-  equal(bundle0.format(msg0), "addon value");
+  equal(bundle0.formatPattern(msg0.value), "addon value");
 
   let bundle1 = (bundles.next()).value;
   equal(bundle1.locales[0], "pl");
   equal(bundle1.hasMessage("key"), true);
   let msg1 = bundle1.getMessage("key");
-  equal(bundle1.format(msg1), "value");
+  equal(bundle1.formatPattern(msg1.value), "value");
 
   equal((bundles.next()).done, true);
 
@@ -326,7 +326,7 @@ add_task(function test_removing() {
   equal(bundle0.locales[0], "pl");
   equal(bundle0.hasMessage("key"), true);
   msg0 = bundle0.getMessage("key");
-  equal(bundle0.format(msg0), "value");
+  equal(bundle0.formatPattern(msg0.value), "value");
 
   equal((bundles.next()).done, true);
 
diff --git a/intl/l10n/test/test_messagecontext.js b/intl/l10n/test/test_messagecontext.js
index 4e72775c1e..9d58bdea5a 100644
--- a/intl/l10n/test/test_messagecontext.js
+++ b/intl/l10n/test/test_messagecontext.js
@@ -2,32 +2,33 @@
    http://creativecommons.org/publicdomain/zero/1.0/ */
 
 function run_test() {
-  const { FluentBundle } = ChromeUtils.import("resource://gre/modules/Fluent.jsm");
+  const { FluentBundle, FluentResource } =
+    ChromeUtils.import("resource://gre/modules/Fluent.jsm");
 
   test_methods_presence(FluentBundle);
-  test_methods_calling(FluentBundle);
+  test_methods_calling(FluentBundle, FluentResource);
 
   ok(true);
 }
 
 function test_methods_presence(FluentBundle) {
   const bundle = new FluentBundle(["en-US", "pl"]);
-  equal(typeof bundle.addMessages, "function");
-  equal(typeof bundle.format, "function");
+  equal(typeof bundle.addResource, "function");
+  equal(typeof bundle.formatPattern, "function");
 }
 
-function test_methods_calling(FluentBundle) {
+function test_methods_calling(FluentBundle, FluentResource) {
   const bundle = new FluentBundle(["en-US", "pl"], {
     useIsolating: false,
   });
-  bundle.addMessages("key = Value");
+  bundle.addResource(new FluentResource("key = Value"));
 
   const msg = bundle.getMessage("key");
-  equal(bundle.format(msg), "Value");
+  equal(bundle.formatPattern(msg.value), "Value");
 
-  bundle.addMessages("key2 = Hello { $name }");
+  bundle.addResource(new FluentResource("key2 = Hello { $name }"));
 
   const msg2 = bundle.getMessage("key2");
-  equal(bundle.format(msg2, { name: "Amy" }), "Hello Amy");
+  equal(bundle.formatPattern(msg2.value, { name: "Amy" }), "Hello Amy");
   ok(true);
 }
diff --git a/intl/locale/components.conf b/intl/locale/components.conf
index 90b80d75de..db1fa832cc 100644
--- a/intl/locale/components.conf
+++ b/intl/locale/components.conf
@@ -4,8 +4,10 @@
 
 Classes = [
     {
+        'js_name': 'locale',
         'cid': '{92735ff4-6384-4ad6-8508-757010e149ee}',
         'contract_ids': ['@mozilla.org/intl/localeservice;1'],
+        'interfaces': ['mozILocaleService'],
         'singleton': True,
         'type': 'mozilla::intl::LocaleService',
         'headers': ['mozilla/intl/LocaleService.h'],
diff --git a/intl/uconv/components.conf b/intl/uconv/components.conf
index 5a7a49a6d4..dd9a9cef96 100644
--- a/intl/uconv/components.conf
+++ b/intl/uconv/components.conf
@@ -22,8 +22,10 @@ Classes = [
         'headers': ['/intl/uconv/nsScriptableUConv.h'],
     },
     {
+        'js_name': 'textToSubURI',
         'cid': '{8b042e22-6f87-11d3-b3c8-00805f8a6670}',
         'contract_ids': ['@mozilla.org/intl/texttosuburi;1'],
+        'interfaces': ['nsITextToSubURI'],
         'type': 'nsTextToSubURI',
         'headers': ['/intl/uconv/nsTextToSubURI.h'],
     },
diff --git a/ipc/chromium/src/base/thread.cc b/ipc/chromium/src/base/thread.cc
index d14a7108ab..d17b883e74 100644
--- a/ipc/chromium/src/base/thread.cc
+++ b/ipc/chromium/src/base/thread.cc
@@ -9,7 +9,7 @@
 #include "base/waitable_event.h"
 #include "GeckoProfiler.h"
 #include "mozilla/EventQueue.h"
-//#include "mozilla/IOInterposer.h"
+#include "mozilla/IOInterposer.h"
 #include "mozilla/ThreadEventQueue.h"
 #include "nsThreadUtils.h"
 #include "nsThreadManager.h"
@@ -162,7 +162,7 @@ void Thread::ThreadMain() {
   }
 
   AUTO_PROFILER_REGISTER_THREAD(name_.c_str());
-  //mozilla::IOInterposer::RegisterCurrentThread();
+  mozilla::IOInterposer::RegisterCurrentThread();
 
   // The message loop for this thread.
   MessageLoop message_loop(startup_data_->options.message_loop_type,
@@ -195,7 +195,7 @@ void Thread::ThreadMain() {
   // Assert that MessageLoop::Quit was called by ThreadQuitTask.
   DCHECK(GetThreadWasQuitProperly());
 
-  //mozilla::IOInterposer::UnregisterCurrentThread();
+  mozilla::IOInterposer::UnregisterCurrentThread();
 
 #ifdef MOZ_TASK_TRACER
   mozilla::tasktracer::FreeTraceInfo();
diff --git a/ipc/glue/BackgroundImpl.cpp b/ipc/glue/BackgroundImpl.cpp
index a03dec9573..595faa33a4 100644
--- a/ipc/glue/BackgroundImpl.cpp
+++ b/ipc/glue/BackgroundImpl.cpp
@@ -1487,7 +1487,7 @@ PBackgroundChild* ChildImpl::GetOrCreateForCurrentThread(
           MOZ_ASSERT(content);
 
           if (!content->SendInitBackground(std::move(aParent))) {
-            MOZ_CRASH("Failed to create top level actor!");
+            NS_WARNING("Failed to create top level actor!");
           }
         });
     if (!runnable) {
@@ -1593,7 +1593,7 @@ PBackgroundChild* ChildImpl::GetOrCreateSocketActorForCurrentThread(
               SocketProcessBridgeChild::GetSingleton();
 
           if (!bridgeChild->SendInitBackground(std::move(aParent))) {
-            MOZ_CRASH("Failed to create top level actor!");
+            NS_WARNING("Failed to create top level actor!");
           }
         });
     if (!runnable) {
diff --git a/ipc/glue/FileDescriptorSetChild.cpp b/ipc/glue/FileDescriptorSetChild.cpp
index 6239baa9b6..5153df9819 100644
--- a/ipc/glue/FileDescriptorSetChild.cpp
+++ b/ipc/glue/FileDescriptorSetChild.cpp
@@ -18,8 +18,7 @@ FileDescriptorSetChild::~FileDescriptorSetChild() {
 
 void FileDescriptorSetChild::ForgetFileDescriptors(
     nsTArray<FileDescriptor>& aFileDescriptors) {
-  aFileDescriptors.Clear();
-  mFileDescriptors.SwapElements(aFileDescriptors);
+  aFileDescriptors = std::move(mFileDescriptors);
 }
 
 mozilla::ipc::IPCResult FileDescriptorSetChild::RecvAddFileDescriptor(
diff --git a/ipc/glue/FileDescriptorSetParent.cpp b/ipc/glue/FileDescriptorSetParent.cpp
index 6519d5ae13..ae81312588 100644
--- a/ipc/glue/FileDescriptorSetParent.cpp
+++ b/ipc/glue/FileDescriptorSetParent.cpp
@@ -16,8 +16,7 @@ FileDescriptorSetParent::~FileDescriptorSetParent() = default;
 
 void FileDescriptorSetParent::ForgetFileDescriptors(
     nsTArray<FileDescriptor>& aFileDescriptors) {
-  aFileDescriptors.Clear();
-  mFileDescriptors.SwapElements(aFileDescriptors);
+  aFileDescriptors = std::move(mFileDescriptors);
 }
 
 void FileDescriptorSetParent::ActorDestroy(ActorDestroyReason aWhy) {
diff --git a/ipc/glue/GeckoChildProcessHost.cpp b/ipc/glue/GeckoChildProcessHost.cpp
index 65a17ab581..114f5e67df 100644
--- a/ipc/glue/GeckoChildProcessHost.cpp
+++ b/ipc/glue/GeckoChildProcessHost.cpp
@@ -35,12 +35,15 @@
 
 #include "mozilla/ipc/BrowserProcessSubThread.h"
 #include "mozilla/ipc/EnvironmentMap.h"
+#include "mozilla/LinkedList.h"
+#include "mozilla/Maybe.h"
 #include "mozilla/Omnijar.h"
 #include "mozilla/RDDProcessHost.h"
 #include "mozilla/Scoped.h"
 #include "mozilla/Services.h"
 #include "mozilla/SharedThreadPool.h"
 #include "mozilla/StaticMutex.h"
+#include "mozilla/TaskQueue.h"
 #include "mozilla/Telemetry.h"
 #include "ProtocolUtils.h"
 #include <sys/stat.h>
@@ -78,7 +81,6 @@
 using mozilla::Monitor2AutoLock;
 using mozilla::Preferences;
 using mozilla::StaticMutexAutoLock;
-using mozilla::ipc::GeckoChildProcessHost;
 
 namespace mozilla {
 MOZ_TYPE_SPECIFIC_SCOPED_POINTER_TEMPLATE(ScopedPRFileDesc, PRFileDesc,
@@ -98,6 +100,196 @@ static bool ShouldHaveDirectoryService() {
   return GeckoProcessType_Default == XRE_GetProcessType();
 }
 
+namespace mozilla {
+namespace ipc {
+
+static Atomic<int32_t> gChildCounter;
+
+static inline nsISerialEventTarget* IOThread() {
+  return XRE_GetIOMessageLoop()->SerialEventTarget();
+}
+
+class BaseProcessLauncher {
+ public:
+  BaseProcessLauncher(GeckoChildProcessHost* aHost,
+                      std::vector<std::string>&& aExtraOpts)
+      : mProcessType(aHost->mProcessType),
+        mLaunchOptions(std::move(aHost->mLaunchOptions)),
+        mExtraOpts(std::move(aExtraOpts)),
+#ifdef XP_WIN
+        mGroupId(aHost->mGroupId),
+#endif
+#if defined(XP_WIN) && defined(MOZ_SANDBOX)
+        mAllowedFilesRead(aHost->mAllowedFilesRead),
+        mSandboxLevel(aHost->mSandboxLevel),
+        mIsFileContent(aHost->mIsFileContent),
+        mEnableSandboxLogging(aHost->mEnableSandboxLogging),
+#endif
+        mTmpDirName(aHost->mTmpDirName),
+        mChildId(++gChildCounter) {
+    SprintfLiteral(mPidString, "%d", base::GetCurrentProcId());
+
+    // Compute the serial event target we'll use for launching.
+    nsCOMPtr<nsIEventTarget> threadOrPool = GetIPCLauncher();
+    mLaunchThread = new TaskQueue(threadOrPool.forget());
+  }
+
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(BaseProcessLauncher);
+
+  RefPtr<ProcessLaunchPromise> Launch(GeckoChildProcessHost*);
+
+ protected:
+  virtual ~BaseProcessLauncher() = default;
+
+  RefPtr<ProcessLaunchPromise> PerformAsyncLaunch();
+  RefPtr<ProcessLaunchPromise> FinishLaunch();
+
+  // Overrideable hooks. If superclass behavior is invoked, it's always at the
+  // top of the override.
+  virtual bool DoSetup();
+  virtual RefPtr<ProcessHandlePromise> DoLaunch() = 0;
+  virtual bool DoFinishLaunch() { return true; };
+
+  void MapChildLogging();
+
+  static BinPathType GetPathToBinary(FilePath&, GeckoProcessType);
+
+  void GetChildLogName(const char* origLogName, nsACString& buffer);
+
+  const char* ChildProcessType() {
+    return XRE_ChildProcessTypeToString(mProcessType);
+  }
+
+  nsCOMPtr<nsIEventTarget> GetIPCLauncher();
+
+  nsCOMPtr<nsISerialEventTarget> mLaunchThread;
+  GeckoProcessType mProcessType;
+  UniquePtr<base::LaunchOptions> mLaunchOptions;
+  std::vector<std::string> mExtraOpts;
+#ifdef XP_WIN
+  nsString mGroupId;
+#endif
+#if defined(XP_WIN) && defined(MOZ_SANDBOX)
+  std::vector<std::wstring> mAllowedFilesRead;
+  int32_t mSandboxLevel;
+  bool mIsFileContent;
+  bool mEnableSandboxLogging;
+#endif
+  nsCString mTmpDirName;
+  LaunchResults mResults = LaunchResults();
+  int32_t mChildId;
+  TimeStamp mStartTimeStamp = TimeStamp::Now();
+  char mPidString[32];
+
+  // Set during launch.
+  IPC::Channel* mChannel = nullptr;
+  std::wstring mChannelId;
+  ScopedPRFileDesc mCrashAnnotationReadPipe;
+  ScopedPRFileDesc mCrashAnnotationWritePipe;
+};
+
+#ifdef XP_WIN
+class WindowsProcessLauncher : public BaseProcessLauncher {
+ public:
+  WindowsProcessLauncher(GeckoChildProcessHost* aHost,
+                         std::vector<std::string>&& aExtraOpts)
+      : BaseProcessLauncher(aHost, std::move(aExtraOpts)) {}
+
+ protected:
+  virtual bool DoSetup() override;
+  virtual RefPtr<ProcessHandlePromise> DoLaunch() override;
+  virtual bool DoFinishLaunch() override;
+
+  mozilla::Maybe<CommandLine> mCmdLine;
+  bool mUseSandbox = false;
+};
+typedef WindowsProcessLauncher ProcessLauncher;
+#endif  // XP_WIN
+
+#ifdef OS_POSIX
+class PosixProcessLauncher : public BaseProcessLauncher {
+ public:
+  PosixProcessLauncher(GeckoChildProcessHost* aHost,
+                       std::vector<std::string>&& aExtraOpts)
+      : BaseProcessLauncher(aHost, std::move(aExtraOpts)) {}
+
+ protected:
+  virtual bool DoSetup() override;
+  virtual RefPtr<ProcessHandlePromise> DoLaunch() override;
+  virtual bool DoFinishLaunch() override;
+
+  std::vector<std::string> mChildArgv;
+};
+
+#  if defined(XP_MACOSX)
+class MacProcessLauncher : public PosixProcessLauncher {
+ public:
+  MacProcessLauncher(GeckoChildProcessHost* aHost,
+                     std::vector<std::string>&& aExtraOpts)
+      : PosixProcessLauncher(aHost, std::move(aExtraOpts)),
+        // Put a random number into the channel name, so that
+        // a compromised renderer can't pretend being the child
+        // that's forked off.
+        mMachConnectionName(
+            StringPrintf("org.mozilla.machname.%d",
+                         base::RandInt(0, std::numeric_limits<int>::max()))),
+        mParentRecvPort(mMachConnectionName.c_str()) {}
+
+ protected:
+  virtual bool DoFinishLaunch() override;
+
+  std::string mMachConnectionName;
+  // We add a mach port to the command line so the child can communicate its
+  // 'task_t' back to the parent.
+  ReceivePort mParentRecvPort;
+
+  friend class PosixProcessLauncher;
+};
+typedef MacProcessLauncher ProcessLauncher;
+#  elif defined(MOZ_WIDGET_ANDROID)
+class AndroidProcessLauncher : public PosixProcessLauncher {
+ public:
+  AndroidProcessLauncher(GeckoChildProcessHost* aHost,
+                         std::vector<std::string>&& aExtraOpts)
+      : PosixProcessLauncher(aHost, std::move(aExtraOpts)) {}
+
+ protected:
+  virtual RefPtr<ProcessHandlePromise> DoLaunch() override;
+  void LaunchAndroidService(
+      const char* type, const std::vector<std::string>& argv,
+      const base::file_handle_mapping_vector& fds_to_remap,
+      base::ProcessHandle* process_handle);
+};
+typedef AndroidProcessLauncher ProcessLauncher;
+// NB: Technically Android is linux (i.e. XP_LINUX is defined), but we want
+// orthogonal IPC machinery there. Conversely, there are tier-3 non-Linux
+// platforms (BSD and Solaris) where we want the "linux" IPC machinery. So
+// we use MOZ_WIDGET_* to choose the platform backend.
+#  elif defined(MOZ_WIDGET_GTK)
+class LinuxProcessLauncher : public PosixProcessLauncher {
+ public:
+  LinuxProcessLauncher(GeckoChildProcessHost* aHost,
+                       std::vector<std::string>&& aExtraOpts)
+      : PosixProcessLauncher(aHost, std::move(aExtraOpts)) {}
+
+ protected:
+  virtual bool DoSetup() override;
+};
+typedef LinuxProcessLauncher ProcessLauncher;
+#  elif
+#    error "Unknown platform"
+#  endif
+#endif  // OS_POSIX
+
+using base::ProcessHandle;
+using mozilla::ipc::BaseProcessLauncher;
+using mozilla::ipc::ProcessLauncher;
+
+mozilla::StaticAutoPtr<mozilla::LinkedList<GeckoChildProcessHost>>
+    GeckoChildProcessHost::sGeckoChildProcessHosts;
+
+mozilla::StaticMutex GeckoChildProcessHost::sMutex;
+
 GeckoChildProcessHost::GeckoChildProcessHost(GeckoProcessType aProcessType,
                                              bool aIsFileContent)
     : mProcessType(aProcessType),
@@ -118,6 +310,11 @@ GeckoChildProcessHost::GeckoChildProcessHost(GeckoProcessType aProcessType,
 #endif
       mDestroying(false) {
   MOZ_COUNT_CTOR(GeckoChildProcessHost);
+  StaticMutexAutoLock lock(sMutex);
+  if (!sGeckoChildProcessHosts) {
+    sGeckoChildProcessHosts = new mozilla::LinkedList<GeckoChildProcessHost>();
+  }
+  sGeckoChildProcessHosts->insertBack(this);
 }
 
 GeckoChildProcessHost::~GeckoChildProcessHost()
@@ -164,23 +361,34 @@ GeckoChildProcessHost::~GeckoChildProcessHost()
 #endif
 }
 
+void GeckoChildProcessHost::RemoveFromProcessList() {
+  StaticMutexAutoLock lock(sMutex);
+  if (!sGeckoChildProcessHosts) {
+    return;
+  }
+  LinkedListElement<GeckoChildProcessHost>::removeFrom(
+      *sGeckoChildProcessHosts);
+}
+
 void GeckoChildProcessHost::Destroy() {
   MOZ_RELEASE_ASSERT(!mDestroying);
-  RefPtr<HandlePromise> whenReady = mHandlePromise;
+  // We can remove from the list before it's really destroyed
+  RemoveFromProcessList();
+  RefPtr<ProcessHandlePromise> whenReady = mHandlePromise;
 
   if (!whenReady) {
     // AsyncLaunch not called yet, so dispatch immediately.
-    whenReady = HandlePromise::CreateAndReject(LaunchError{}, __func__);
+    whenReady = ProcessHandlePromise::CreateAndReject(LaunchError{}, __func__);
   }
 
-  using Value = HandlePromise::ResolveOrRejectValue;
+  using Value = ProcessHandlePromise::ResolveOrRejectValue;
   mDestroying = true;
   whenReady->Then(XRE_GetIOMessageLoop()->SerialEventTarget(), __func__,
                   [this](const Value&) { delete this; });
 }
 
 // static
-mozilla::BinPathType GeckoChildProcessHost::GetPathToBinary(
+mozilla::BinPathType BaseProcessLauncher::GetPathToBinary(
     FilePath& exePath, GeckoProcessType processType) {
   BinPathType pathType = XRE_GetChildProcBinPathType(processType);
 
@@ -372,18 +580,72 @@ bool GeckoChildProcessHost::AsyncLaunch(std::vector<std::string> aExtraOpts) {
   }
 #endif
 
-  MessageLoop* ioLoop = XRE_GetIOMessageLoop();
+  RefPtr<BaseProcessLauncher> launcher =
+      new ProcessLauncher(this, std::move(aExtraOpts));
 
+  // Note: Destroy() waits on mHandlePromise to delete |this|. As such, we want
+  // to be sure that all of our post-launch processing on |this| happens before
+  // mHandlePromise notifies.
   MOZ_ASSERT(mHandlePromise == nullptr);
-  mHandlePromise = new HandlePromise::Private(__func__);
+  RefPtr<ProcessHandlePromise::Private> p =
+      new ProcessHandlePromise::Private(__func__);
+  mHandlePromise = p;
 
-  // Currently this can't fail (see the MOZ_ALWAYS_SUCCEEDS in
-  // MessageLoop::PostTask_Helper), but in the future it possibly
-  // could, in which case this method could return false.
-  ioLoop->PostTask(NewNonOwningRunnableMethod<std::vector<std::string>>(
-      "ipc::GeckoChildProcessHost::RunPerformAsyncLaunch", this,
-      &GeckoChildProcessHost::RunPerformAsyncLaunch, aExtraOpts));
+  mozilla::InvokeAsync<GeckoChildProcessHost*>(
+      IOThread(), launcher.get(), __func__, &BaseProcessLauncher::Launch, this)
+      ->Then(
+          IOThread(), __func__,
+          [this, p](const LaunchResults aResults) {
+            {
+              if (!OpenPrivilegedHandle(base::GetProcId(aResults.mHandle))
+#ifdef XP_WIN
+                  // If we failed in opening the process handle, try harder by
+                  // duplicating one.
+                  && !::DuplicateHandle(::GetCurrentProcess(), aResults.mHandle,
+                                        ::GetCurrentProcess(),
+                                        &mChildProcessHandle,
+                                        PROCESS_DUP_HANDLE | PROCESS_TERMINATE |
+                                            PROCESS_QUERY_INFORMATION |
+                                            PROCESS_VM_READ | SYNCHRONIZE,
+                                        FALSE, 0)
+#endif  // XP_WIN
+              ) {
+                MOZ_CRASH("cannot open handle to child process");
+              }
 
+#ifdef XP_MACOSX
+              this->mChildTask = aResults.mChildTask;
+#endif
+#if defined(XP_WIN) && defined(MOZ_SANDBOX)
+              this->mSandboxBroker = aResults.mSandboxBroker;
+#endif
+
+              Monitor2AutoLock lock(mMonitor);
+              // The OnChannel{Connected,Error} may have already advanced the
+              // state.
+              if (mProcessState < PROCESS_CREATED) {
+                mProcessState = PROCESS_CREATED;
+              }
+              lock.Signal();
+            }
+            p->Resolve(aResults.mHandle, __func__);
+          },
+          [this, p](const LaunchError aError) {
+            // WaitUntilConnected might be waiting for us to signal.
+            // If something failed let's set the error state and notify.
+            CHROMIUM_LOG(ERROR)
+                << "Failed to launch "
+                << XRE_ChildProcessTypeToString(mProcessType) << " subprocess";
+            Telemetry::Accumulate(
+                Telemetry::SUBPROCESS_LAUNCH_FAILURE,
+                nsDependentCString(XRE_ChildProcessTypeToString(mProcessType)));
+            {
+              Monitor2AutoLock lock(mMonitor);
+              mProcessState = PROCESS_ERROR;
+              lock.Signal();
+            }
+            p->Reject(aError, __func__);
+          });
   return true;
 }
 
@@ -466,10 +728,8 @@ void GeckoChildProcessHost::SetAlreadyDead() {
   mChildProcessHandle = 0;
 }
 
-int32_t GeckoChildProcessHost::mChildCounter = 0;
-
-void GeckoChildProcessHost::GetChildLogName(const char* origLogName,
-                                            nsACString& buffer) {
+void BaseProcessLauncher::GetChildLogName(const char* origLogName,
+                                          nsACString& buffer) {
 #ifdef XP_WIN
   // On Windows we must expand relative paths because sandboxing rules
   // bound only to full paths.  fopen fowards to NtCreateFile which checks
@@ -498,10 +758,9 @@ void GeckoChildProcessHost::GetChildLogName(const char* origLogName,
 
   // Append child-specific postfix to name
   buffer.AppendLiteral(".child-");
-  buffer.AppendInt(mChildCounter);
+  buffer.AppendInt(gChildCounter);
 }
 
-namespace {
 // Windows needs a single dedicated thread for process launching,
 // because of thread-safety restrictions/assertions in the sandbox
 // code.  (This implementation isn't itself Windows-specific, so
@@ -536,7 +795,7 @@ IPCLaunchThreadObserver::Observe(nsISupports* aSubject, const char* aTopic,
   return rv;
 }
 
-static nsCOMPtr<nsIEventTarget> GetIPCLauncher() {
+nsCOMPtr<nsIEventTarget> BaseProcessLauncher::GetIPCLauncher() {
   StaticMutexAutoLock lock(gIPCLaunchThreadMutex);
   if (!gIPCLaunchThread) {
     nsCOMPtr<nsIThread> thread;
@@ -555,6 +814,7 @@ static nsCOMPtr<nsIEventTarget> GetIPCLauncher() {
   }
 
   nsCOMPtr<nsIEventTarget> thread = gIPCLaunchThread.get();
+  MOZ_DIAGNOSTIC_ASSERT(thread);
   return thread;
 }
 
@@ -562,57 +822,14 @@ static nsCOMPtr<nsIEventTarget> GetIPCLauncher() {
 
 // Non-Windows platforms can use an on-demand thread pool.
 
-static nsCOMPtr<nsIEventTarget> GetIPCLauncher() {
+nsCOMPtr<nsIEventTarget> BaseProcessLauncher::GetIPCLauncher() {
   nsCOMPtr<nsIEventTarget> pool =
       mozilla::SharedThreadPool::Get(NS_LITERAL_CSTRING("IPC Launch"));
+  MOZ_DIAGNOSTIC_ASSERT(pool);
   return pool;
 }
 
 #endif  // XP_WIN
-}  // anonymous namespace
-
-void GeckoChildProcessHost::RunPerformAsyncLaunch(
-    std::vector<std::string> aExtraOpts) {
-  // Warning: rejecting the promise allows `this` to be deleted.  Do
-  // not use `this` after calling the `fail` function (including
-  // destructors of AutoLock objects).
-  //
-  // (Deletion happens on the I/O thread, so it's safe to access
-  // `this` afterwards from RunPerformAsyncLaunch itself, but not from
-  // the launchWrapper closure.  For simplicity, it's just treated
-  // like `delete this` everywhere.)
-  auto fail = [this] {
-    {
-      Monitor2AutoLock lock(mMonitor);
-      mProcessState = PROCESS_ERROR;
-      lock.Signal();
-    }
-    mHandlePromise->Reject(LaunchError{}, __func__);
-  };
-
-  // This (probably?) needs to happen on the I/O thread.
-  InitializeChannel();
-
-  // But the rest of this doesn't, and shouldn't block IPC messages:
-  auto launchWrapper = [this, fail, aExtraOpts = std::move(aExtraOpts)]() {
-    bool ok = PerformAsyncLaunch(aExtraOpts);
-
-    if (!ok) {
-      // WaitUntilConnected might be waiting for us to signal.
-      // If something failed let's set the error state and notify.
-      CHROMIUM_LOG(ERROR) << "Failed to launch "
-                          << XRE_ChildProcessTypeToString(mProcessType)
-                          << " subprocess";
-      Telemetry::Accumulate(
-          Telemetry::SUBPROCESS_LAUNCH_FAILURE,
-          nsDependentCString(XRE_ChildProcessTypeToString(mProcessType)));
-      fail();
-    }
-  };
-
-  // Fall back to launching on the I/O thread.
-  launchWrapper();
-}
 
 void
 #if defined(XP_WIN)
@@ -682,21 +899,38 @@ static bool Contains(const std::vector<std::string>& aExtraOpts,
 }
 #endif  // defined(XP_WIN) && (defined(MOZ_SANDBOX) || defined(_ARM64_))
 
-bool GeckoChildProcessHost::PerformAsyncLaunch(
-    std::vector<std::string> aExtraOpts) {
+RefPtr<ProcessLaunchPromise> BaseProcessLauncher::PerformAsyncLaunch() {
+  if (!DoSetup()) {
+    return ProcessLaunchPromise::CreateAndReject(LaunchError{}, __func__);
+  }
+  RefPtr<BaseProcessLauncher> self = this;
+  return DoLaunch()->Then(
+      mLaunchThread, __func__,
+      [self](base::ProcessHandle aHandle) {
+        self->mResults.mHandle = aHandle;
+        return self->FinishLaunch();
+      },
+      [](LaunchError aError) {
+        return ProcessLaunchPromise::CreateAndReject(aError, __func__);
+      });
+}
+
+bool BaseProcessLauncher::DoSetup() {
 #ifdef MOZ_GECKO_PROFILER
-  GetProfilerEnvVarsForChildProcess([this](const char* key, const char* value) {
-    mLaunchOptions->env_map[ENVIRONMENT_STRING(key)] =
+  RefPtr<BaseProcessLauncher> self = this;
+  GetProfilerEnvVarsForChildProcess([self](const char* key, const char* value) {
+    self->mLaunchOptions->env_map[ENVIRONMENT_STRING(key)] =
         ENVIRONMENT_STRING(value);
   });
 #endif
 
-  const auto startTS = TimeStamp::Now();
+  MapChildLogging();
 
-  // - Note: this code is not called re-entrantly, nor are restoreOrig*LogName
-  //   or mChildCounter touched by any other thread, so this is safe.
-  ++mChildCounter;
+  return PR_CreatePipe(&mCrashAnnotationReadPipe.rwget(),
+                       &mCrashAnnotationWritePipe.rwget()) == PR_SUCCESS;
+}
 
+void BaseProcessLauncher::MapChildLogging() {
   const char* origNSPRLogName = PR_GetEnv("NSPR_LOG_FILE");
   const char* origMozLogName = PR_GetEnv("MOZ_LOG_FILE");
 
@@ -719,52 +953,14 @@ bool GeckoChildProcessHost::PerformAsyncLaunch(
     mLaunchOptions->env_map[ENVIRONMENT_LITERAL("RUST_LOG")] =
         ENVIRONMENT_STRING(childRustLog.get());
   }
+}
 
-#if defined(XP_LINUX) && defined(MOZ_SANDBOX)
-  if (!mTmpDirName.IsEmpty()) {
-    // Point a bunch of things that might want to write from content to our
-    // shiny new content-process specific tmpdir
-    mLaunchOptions->env_map[ENVIRONMENT_LITERAL("TMPDIR")] =
-        ENVIRONMENT_STRING(mTmpDirName.get());
-    // Partial fix for bug 1380051 (not persistent - should be)
-    mLaunchOptions->env_map[ENVIRONMENT_LITERAL("MESA_GLSL_CACHE_DIR")] =
-        ENVIRONMENT_STRING(mTmpDirName.get());
-  }
-#endif
-
-  // We rely on the fact that InitializeChannel() has already been processed
-  // on the IO thread before this point is reached.
-  if (!GetChannel()) {
+#if defined(MOZ_WIDGET_GTK)
+bool LinuxProcessLauncher::DoSetup() {
+  if (!PosixProcessLauncher::DoSetup()) {
     return false;
   }
 
-  base::ProcessHandle process = 0;
-
-  // send the child the PID so that it can open a ProcessHandle back to us.
-  // probably don't want to do this in the long run
-  char pidstring[32];
-  SprintfLiteral(pidstring, "%d", base::GetCurrentProcId());
-
-  const char* const childProcessType =
-      XRE_ChildProcessTypeToString(mProcessType);
-
-  ScopedPRFileDesc crashAnnotationReadPipe;
-  ScopedPRFileDesc crashAnnotationWritePipe;
-  if (PR_CreatePipe(&crashAnnotationReadPipe.rwget(),
-                    &crashAnnotationWritePipe.rwget()) != PR_SUCCESS) {
-    return false;
-  }
-
-//--------------------------------------------------
-#if defined(OS_POSIX)
-  // For POSIX, we have to be extremely anal about *not* using
-  // std::wstring in code compiled with Mozilla's -fshort-wchar
-  // configuration, because chromium is compiled with -fno-short-wchar
-  // and passing wstrings from one config to the other is unsafe.  So
-  // we split the logic here.
-
-#  if defined(OS_POSIX)
-#    if defined(MOZ_WIDGET_GTK)
   if (mProcessType == GeckoProcessType_Content) {
     // disable IM module to avoid sandbox violation
     mLaunchOptions->env_map["GTK_IM_MODULE"] = "gtk-im-context-simple";
@@ -774,7 +970,28 @@ bool GeckoChildProcessHost::PerformAsyncLaunch(
     // anyway.
     mLaunchOptions->env_map["NO_AT_BRIDGE"] = "1";
   }
-#    endif  // defined(MOZ_WIDGET_GTK)
+
+#  ifdef MOZ_SANDBOX
+  if (!mTmpDirName.IsEmpty()) {
+    // Point a bunch of things that might want to write from content to our
+    // shiny new content-process specific tmpdir
+    mLaunchOptions->env_map[ENVIRONMENT_LITERAL("TMPDIR")] =
+        ENVIRONMENT_STRING(mTmpDirName.get());
+    // Partial fix for bug 1380051 (not persistent - should be)
+    mLaunchOptions->env_map[ENVIRONMENT_LITERAL("MESA_GLSL_CACHE_DIR")] =
+        ENVIRONMENT_STRING(mTmpDirName.get());
+  }
+#  endif  // MOZ_SANDBOX
+
+  return true;
+}
+#endif  // MOZ_WIDGET_GTK
+
+#ifdef OS_POSIX
+bool PosixProcessLauncher::DoSetup() {
+  if (!BaseProcessLauncher::DoSetup()) {
+    return false;
+  }
 
   // XPCOM may not be initialized in some subprocesses.  We don't want
   // to initialize XPCOM just for the directory service, especially
@@ -784,23 +1001,23 @@ bool GeckoChildProcessHost::PerformAsyncLaunch(
     MOZ_ASSERT(gGREBinPath);
     nsCString path;
     NS_CopyUnicodeToNative(nsDependentString(gGREBinPath), path);
-#    if defined(OS_LINUX) || defined(OS_BSD)
+#  if defined(OS_LINUX) || defined(OS_BSD)
     const char* ld_library_path = PR_GetEnv("LD_LIBRARY_PATH");
     nsCString new_ld_lib_path(path.get());
 
-#      ifdef MOZ_WIDGET_GTK
+#    ifdef MOZ_WIDGET_GTK
     if (mProcessType == GeckoProcessType_Plugin) {
       new_ld_lib_path.AppendLiteral("/gtk2:");
       new_ld_lib_path.Append(path.get());
     }
-#      endif  // MOZ_WIDGET_GTK
+#    endif  // MOZ_WIDGET_GTK
     if (ld_library_path && *ld_library_path) {
       new_ld_lib_path.Append(':');
       new_ld_lib_path.Append(ld_library_path);
     }
     mLaunchOptions->env_map["LD_LIBRARY_PATH"] = new_ld_lib_path.get();
 
-#    elif OS_MACOSX  // defined(OS_LINUX) || defined(OS_BSD)
+#  elif OS_MACOSX  // defined(OS_LINUX) || defined(OS_BSD)
     mLaunchOptions->env_map["DYLD_LIBRARY_PATH"] = path.get();
     // XXX DYLD_INSERT_LIBRARIES should only be set when launching a plugin
     //     process, and has no effect on other subprocesses (the hooks in
@@ -821,9 +1038,8 @@ bool GeckoChildProcessHost::PerformAsyncLaunch(
     interpose.Append(path.get());
     interpose.AppendLiteral("/libplugin_child_interpose.dylib");
     mLaunchOptions->env_map["DYLD_INSERT_LIBRARIES"] = interpose.get();
-#    endif           // defined(OS_LINUX) || defined(OS_BSD)
+#  endif           // defined(OS_LINUX) || defined(OS_BSD)
   }
-#  endif  // defined(OS_POSIX)
 
   FilePath exePath;
   BinPathType pathType = GetPathToBinary(exePath, mProcessType);
@@ -831,22 +1047,20 @@ bool GeckoChildProcessHost::PerformAsyncLaunch(
   // remap the IPC socket fd to a well-known int, as the OS does for
   // STDOUT_FILENO, for example
   int srcChannelFd, dstChannelFd;
-  channel().GetClientFileDescriptorMapping(&srcChannelFd, &dstChannelFd);
+  mChannel->GetClientFileDescriptorMapping(&srcChannelFd, &dstChannelFd);
   mLaunchOptions->fds_to_remap.push_back(
       std::pair<int, int>(srcChannelFd, dstChannelFd));
 
   // no need for kProcessChannelID, the child process inherits the
   // other end of the socketpair() from us
 
-  std::vector<std::string> childArgv;
-
-  childArgv.push_back(exePath.value());
+  mChildArgv.push_back(exePath.value());
 
   if (pathType == BinPathType::Self) {
-    childArgv.push_back("-contentproc");
+    mChildArgv.push_back("-contentproc");
   }
 
-  childArgv.insert(childArgv.end(), aExtraOpts.begin(), aExtraOpts.end());
+  mChildArgv.insert(mChildArgv.end(), mExtraOpts.begin(), mExtraOpts.end());
 
   if (mProcessType != GeckoProcessType_GMPlugin) {
     if (Omnijar::IsInitialized()) {
@@ -855,20 +1069,20 @@ bool GeckoChildProcessHost::PerformAsyncLaunch(
       nsAutoCString path;
       nsCOMPtr<nsIFile> file = Omnijar::GetPath(Omnijar::GRE);
       if (file && NS_SUCCEEDED(file->GetNativePath(path))) {
-        childArgv.push_back("-greomni");
-        childArgv.push_back(path.get());
+        mChildArgv.push_back("-greomni");
+        mChildArgv.push_back(path.get());
       }
       file = Omnijar::GetPath(Omnijar::APP);
       if (file && NS_SUCCEEDED(file->GetNativePath(path))) {
-        childArgv.push_back("-appomni");
-        childArgv.push_back(path.get());
+        mChildArgv.push_back("-appomni");
+        mChildArgv.push_back(path.get());
       }
     }
     // Add the application directory path (-appdir path)
-    AddAppDirToCommandLine(childArgv);
+    AddAppDirToCommandLine(mChildArgv);
   }
 
-  childArgv.push_back(pidstring);
+  mChildArgv.push_back(mPidString);
 
   if (!CrashReporter::IsDummy()) {
 #  if defined(OS_LINUX) || defined(OS_BSD) || defined(OS_SOLARIS)
@@ -882,62 +1096,78 @@ bool GeckoChildProcessHost::PerformAsyncLaunch(
       mLaunchOptions->fds_to_remap.push_back(
           std::pair<int, int>(childCrashFd, childCrashRemapFd));
       // "true" == crash reporting enabled
-      childArgv.push_back("true");
+      mChildArgv.push_back("true");
     } else {
       // "false" == crash reporting disabled
-      childArgv.push_back("false");
+      mChildArgv.push_back("false");
     }
 #  elif defined(MOZ_WIDGET_COCOA) /* defined(OS_LINUX) || defined(OS_BSD) || \
                                      defined(OS_SOLARIS) */
-    childArgv.push_back(CrashReporter::GetChildNotificationPipe());
+    mChildArgv.push_back(CrashReporter::GetChildNotificationPipe());
 #  endif  // defined(OS_LINUX) || defined(OS_BSD) || defined(OS_SOLARIS)
   }
 
-  int fd = PR_FileDesc2NativeHandle(crashAnnotationWritePipe);
+  int fd = PR_FileDesc2NativeHandle(mCrashAnnotationWritePipe);
   mLaunchOptions->fds_to_remap.push_back(
       std::make_pair(fd, CrashReporter::GetAnnotationTimeCrashFd()));
 
 #  ifdef MOZ_WIDGET_COCOA
-  // Add a mach port to the command line so the child can communicate its
-  // 'task_t' back to the parent.
-  //
-  // Put a random number into the channel name, so that a compromised renderer
-  // can't pretend being the child that's forked off.
-  std::string mach_connection_name =
-      StringPrintf("org.mozilla.machname.%d",
-                   base::RandInt(0, std::numeric_limits<int>::max()));
-  childArgv.push_back(mach_connection_name.c_str());
+  mChildArgv.push_back(
+      static_cast<MacProcessLauncher*>(this)->mMachConnectionName.c_str());
 #  endif  // MOZ_WIDGET_COCOA
 
-  childArgv.push_back(childProcessType);
+  mChildArgv.push_back(ChildProcessType());
 
-#  ifdef MOZ_WIDGET_COCOA
-  // Register the listening port before launching the child, to ensure
-  // that it's there when the child tries to look it up.
-  ReceivePort parent_recv_port(mach_connection_name.c_str());
-#  endif  // MOZ_WIDGET_COCOA
+  return true;
+}
+#endif  // OS_POSIX
 
-#  if defined(MOZ_WIDGET_ANDROID)
-  LaunchAndroidService(childProcessType, childArgv,
-                       mLaunchOptions->fds_to_remap, &process);
-#  else   // goes with defined(MOZ_WIDGET_ANDROID)
-  if (!base::LaunchApp(childArgv, *mLaunchOptions, &process)) {
+#if defined(MOZ_WIDGET_ANDROID)
+RefPtr<ProcessHandlePromise> AndroidProcessLauncher::DoLaunch() {
+  ProcessHandle handle = 0;
+  LaunchAndroidService(ChildProcessType(), mChildArgv,
+                       mLaunchOptions->fds_to_remap, &handle);
+  return handle != 0
+             ? ProcessHandlePromise::CreateAndResolve(handle, __func__)
+             : ProcessHandlePromise::CreateAndReject(LaunchError{}, __func__);
+}
+#endif  // MOZ_WIDGET_ANDROID
+
+#ifdef OS_POSIX
+RefPtr<ProcessHandlePromise> PosixProcessLauncher::DoLaunch() {
+  ProcessHandle handle = 0;
+  if (!base::LaunchApp(mChildArgv, *mLaunchOptions, &handle)) {
+    return ProcessHandlePromise::CreateAndReject(LaunchError{}, __func__);
+  }
+  return ProcessHandlePromise::CreateAndResolve(handle, __func__);
+}
+
+bool PosixProcessLauncher::DoFinishLaunch() {
+  if (!BaseProcessLauncher::DoFinishLaunch()) {
     return false;
   }
-#  endif  // defined(MOZ_WIDGET_ANDROID)
 
   // We're in the parent and the child was launched. Close the child FD in the
   // parent as soon as possible, which will allow the parent to detect when the
   // child closes its FD (either due to normal exit or due to crash).
-  GetChannel()->CloseClientFileDescriptor();
+  mChannel->CloseClientFileDescriptor();
+
+  return true;
+}
+#endif  // OS_POSIX
+
+#ifdef XP_MACOSX
+bool MacProcessLauncher::DoFinishLaunch() {
+  if (!PosixProcessLauncher::DoFinishLaunch()) {
+    return false;
+  }
 
-#  ifdef MOZ_WIDGET_COCOA
   // Wait for the child process to send us its 'task_t' data.
   const int kTimeoutMs = 10000;
 
   MachReceiveMessage child_message;
   kern_return_t err =
-      parent_recv_port.WaitForMessage(&child_message, kTimeoutMs);
+      mParentRecvPort.WaitForMessage(&child_message, kTimeoutMs);
   if (err != KERN_SUCCESS) {
     std::string errString =
         StringPrintf("0x%x %s", err, mach_error_string(err));
@@ -1002,22 +1232,32 @@ bool GeckoChildProcessHost::PerformAsyncLaunch(
   }
 
   SharedMemoryBasic::SetupMachMemory(
-      process, parent_recv_port_memory, parent_recv_port_memory_ack,
+      mResults.mHandle, parent_recv_port_memory, parent_recv_port_memory_ack,
       parent_send_port_memory, parent_send_port_memory_ack, false);
 
-#  endif  // MOZ_WIDGET_COCOA
+  // NB: on OS X, we block much longer than we need to in order to
+  // reach this call, waiting for the child process's task_t.  The
+  // best way to fix that is to refactor this file, hard.
+  mResults.mChildTask = child_task;
 
-//--------------------------------------------------
-#elif defined(OS_WIN)  // defined(OS_POSIX)
+  return true;
+}
+#endif  // XP_MACOSX
+
+#ifdef XP_WIN
+bool WindowsProcessLauncher::DoSetup() {
+  if (!BaseProcessLauncher::DoSetup()) {
+    return false;
+  }
 
   FilePath exePath;
   BinPathType pathType = GetPathToBinary(exePath, mProcessType);
 
 #  if defined(MOZ_SANDBOX) || defined(_ARM64_)
   const bool isGMP = mProcessType == GeckoProcessType_GMPlugin;
-  const bool isWidevine = isGMP && Contains(aExtraOpts, "gmp-widevinecdm");
+  const bool isWidevine = isGMP && Contains(mExtraOpts, "gmp-widevinecdm");
 #    if defined(_ARM64_)
-  const bool isClearKey = isGMP && Contains(aExtraOpts, "gmp-clearkey");
+  const bool isClearKey = isGMP && Contains(mExtraOpts, "gmp-clearkey");
   const bool isSandboxBroker =
       mProcessType == GeckoProcessType_RemoteSandboxBroker;
   if (isClearKey || isWidevine || isSandboxBroker) {
@@ -1030,17 +1270,17 @@ bool GeckoChildProcessHost::PerformAsyncLaunch(
 #    endif  // if defined(_ARM64_)
 #  endif    // defined(MOZ_SANDBOX) || defined(_ARM64_)
 
-  CommandLine cmdLine(exePath.ToWStringHack());
+  mCmdLine.emplace(exePath.ToWStringHack());
 
   if (pathType == BinPathType::Self) {
-    cmdLine.AppendLooseValue(UTF8ToWide("-contentproc"));
+    mCmdLine->AppendLooseValue(UTF8ToWide("-contentproc"));
   }
 
-  cmdLine.AppendSwitchWithValue(switches::kProcessChannelID, channel_id());
+  mCmdLine->AppendSwitchWithValue(switches::kProcessChannelID, mChannelId);
 
-  for (std::vector<std::string>::iterator it = aExtraOpts.begin();
-       it != aExtraOpts.end(); ++it) {
-    cmdLine.AppendLooseValue(UTF8ToWide(*it));
+  for (std::vector<std::string>::iterator it = mExtraOpts.begin();
+       it != mExtraOpts.end(); ++it) {
+    mCmdLine->AppendLooseValue(UTF8ToWide(*it));
   }
 
   if (Omnijar::IsInitialized()) {
@@ -1049,25 +1289,23 @@ bool GeckoChildProcessHost::PerformAsyncLaunch(
     nsAutoString path;
     nsCOMPtr<nsIFile> file = Omnijar::GetPath(Omnijar::GRE);
     if (file && NS_SUCCEEDED(file->GetPath(path))) {
-      cmdLine.AppendLooseValue(UTF8ToWide("-greomni"));
-      cmdLine.AppendLooseValue(path.get());
+      mCmdLine->AppendLooseValue(UTF8ToWide("-greomni"));
+      mCmdLine->AppendLooseValue(path.get());
     }
     file = Omnijar::GetPath(Omnijar::APP);
     if (file && NS_SUCCEEDED(file->GetPath(path))) {
-      cmdLine.AppendLooseValue(UTF8ToWide("-appomni"));
-      cmdLine.AppendLooseValue(path.get());
+      mCmdLine->AppendLooseValue(UTF8ToWide("-appomni"));
+      mCmdLine->AppendLooseValue(path.get());
     }
   }
 
 #  if defined(MOZ_SANDBOX)
 #    if defined(_ARM64_)
   if (isClearKey || isWidevine)
-    mSandboxBroker = new RemoteSandboxBroker();
+    mResults.mSandboxBroker = new RemoteSandboxBroker();
   else
 #    endif  // if defined(_ARM64_)
-    mSandboxBroker = new SandboxBroker();
-
-  bool shouldSandboxCurrentProcess = false;
+    mResults.mSandboxBroker = new SandboxBroker();
 
   // XXX: Bug 1124167: We should get rid of the process specific logic for
   // sandboxing in this class at some point. Unfortunately it will take a bit
@@ -1079,19 +1317,18 @@ bool GeckoChildProcessHost::PerformAsyncLaunch(
         // SetSecurityLevelForContentProcess and just crash there right away.
         // Should this change in the future then we should also handle the error
         // here.
-        mSandboxBroker->SetSecurityLevelForContentProcess(mSandboxLevel,
-                                                          mIsFileContent);
-        shouldSandboxCurrentProcess = true;
+        mResults.mSandboxBroker->SetSecurityLevelForContentProcess(
+            mSandboxLevel, mIsFileContent);
+        mUseSandbox = true;
       }
       break;
     case GeckoProcessType_Plugin:
       if (mSandboxLevel > 0 && !PR_GetEnv("MOZ_DISABLE_NPAPI_SANDBOX")) {
-        bool ok =
-            mSandboxBroker->SetSecurityLevelForPluginProcess(mSandboxLevel);
-        if (!ok) {
+        if (!mResults.mSandboxBroker->SetSecurityLevelForPluginProcess(
+                mSandboxLevel)) {
           return false;
         }
-        shouldSandboxCurrentProcess = true;
+        mUseSandbox = true;
       }
       break;
     case GeckoProcessType_IPDLUnitTest:
@@ -1105,11 +1342,10 @@ bool GeckoChildProcessHost::PerformAsyncLaunch(
         // so use sandbox level USER_RESTRICTED instead of USER_LOCKDOWN.
         auto level =
             isWidevine ? SandboxBroker::Restricted : SandboxBroker::LockDown;
-        bool ok = mSandboxBroker->SetSecurityLevelForGMPlugin(level);
-        if (!ok) {
+        if (!mResults.mSandboxBroker->SetSecurityLevelForGMPlugin(level)) {
           return false;
         }
-        shouldSandboxCurrentProcess = true;
+        mUseSandbox = true;
       }
       break;
     case GeckoProcessType_GPU:
@@ -1117,8 +1353,8 @@ bool GeckoChildProcessHost::PerformAsyncLaunch(
         // For now we treat every failure as fatal in
         // SetSecurityLevelForGPUProcess and just crash there right away. Should
         // this change in the future then we should also handle the error here.
-        mSandboxBroker->SetSecurityLevelForGPUProcess(mSandboxLevel);
-        shouldSandboxCurrentProcess = true;
+        mResults.mSandboxBroker->SetSecurityLevelForGPUProcess(mSandboxLevel);
+        mUseSandbox = true;
       }
       break;
     case GeckoProcessType_VR:
@@ -1128,10 +1364,10 @@ bool GeckoChildProcessHost::PerformAsyncLaunch(
       break;
     case GeckoProcessType_RDD:
       if (!PR_GetEnv("MOZ_DISABLE_RDD_SANDBOX")) {
-        if (!mSandboxBroker->SetSecurityLevelForRDDProcess()) {
+        if (!mResults.mSandboxBroker->SetSecurityLevelForRDDProcess()) {
           return false;
         }
-        shouldSandboxCurrentProcess = true;
+        mUseSandbox = true;
       }
       break;
     case GeckoProcessType_Socket:
@@ -1146,132 +1382,117 @@ bool GeckoChildProcessHost::PerformAsyncLaunch(
       break;
   };
 
-  if (shouldSandboxCurrentProcess) {
+  if (mUseSandbox) {
     for (auto it = mAllowedFilesRead.begin(); it != mAllowedFilesRead.end();
          ++it) {
-      mSandboxBroker->AllowReadFile(it->c_str());
+      mResults.mSandboxBroker->AllowReadFile(it->c_str());
     }
   }
-#  endif    // defined(MOZ_SANDBOX)
+#  endif  // defined(MOZ_SANDBOX)
 
   // Add the application directory path (-appdir path)
-  AddAppDirToCommandLine(cmdLine);
+  AddAppDirToCommandLine(mCmdLine.ref());
 
   // XXX Command line params past this point are expected to be at
   // the end of the command line string, and in a specific order.
   // See XRE_InitChildProcess in nsEmbedFunction.
 
   // Win app model id
-  cmdLine.AppendLooseValue(mGroupId.get());
+  mCmdLine->AppendLooseValue(mGroupId.get());
 
   // Process id
-  cmdLine.AppendLooseValue(UTF8ToWide(pidstring));
+  mCmdLine->AppendLooseValue(UTF8ToWide(mPidString));
 
-  cmdLine.AppendLooseValue(
+  mCmdLine->AppendLooseValue(
       UTF8ToWide(CrashReporter::GetChildNotificationPipe()));
 
   if (!CrashReporter::IsDummy()) {
-    PROsfd h = PR_FileDesc2NativeHandle(crashAnnotationWritePipe);
+    PROsfd h = PR_FileDesc2NativeHandle(mCrashAnnotationWritePipe);
     mLaunchOptions->handles_to_inherit.push_back(reinterpret_cast<HANDLE>(h));
     std::string hStr = std::to_string(h);
-    cmdLine.AppendLooseValue(UTF8ToWide(hStr));
+    mCmdLine->AppendLooseValue(UTF8ToWide(hStr));
   }
 
   // Process type
-  cmdLine.AppendLooseValue(UTF8ToWide(childProcessType));
-
-#  if defined(MOZ_SANDBOX)
-  if (shouldSandboxCurrentProcess) {
-    // Mark the handles to inherit as inheritable.
-    for (HANDLE h : mLaunchOptions->handles_to_inherit) {
-      mSandboxBroker->AddHandleToShare(h);
-    }
-
-    if (mSandboxBroker->LaunchApp(cmdLine.program().c_str(),
-                                  cmdLine.command_line_string().c_str(),
-                                  mLaunchOptions->env_map, mProcessType,
-                                  mEnableSandboxLogging, &process)) {
-      EnvironmentLog("MOZ_PROCESS_LOG")
-          .print("==> process %d launched child process %d (%S)\n",
-                 base::GetCurrentProcId(), base::GetProcId(process),
-                 cmdLine.command_line_string().c_str());
-    } else {
-      return false;
-    }
-  } else
-#  endif  // defined(MOZ_SANDBOX)
-  {
-    if (!base::LaunchApp(cmdLine, *mLaunchOptions, &process)) {
-      return false;
-    }
+  mCmdLine->AppendLooseValue(UTF8ToWide(ChildProcessType()));
 
 #  ifdef MOZ_SANDBOX
-    // We need to be able to duplicate handles to some types of non-sandboxed
-    // child processes.
-    switch (mProcessType) {
-      case GeckoProcessType_Default:
-        MOZ_CRASH("shouldn't be launching a parent process");
-      case GeckoProcessType_Plugin:
-      case GeckoProcessType_IPDLUnitTest:
-        // No handle duplication necessary.
-        break;
-      default:
-        if (!SandboxBroker::AddTargetPeer(process)) {
-          NS_WARNING("Failed to add child process as target peer.");
-        }
-        break;
+  if (mUseSandbox) {
+    // Mark the handles to inherit as inheritable.
+    for (HANDLE h : mLaunchOptions->handles_to_inherit) {
+      mResults.mSandboxBroker->AddHandleToShare(h);
     }
+  }
 #  endif  // MOZ_SANDBOX
+
+  return true;
+}
+
+RefPtr<ProcessHandlePromise> WindowsProcessLauncher::DoLaunch() {
+  ProcessHandle handle = 0;
+#  ifdef MOZ_SANDBOX
+  if (mUseSandbox) {
+    if (mResults.mSandboxBroker->LaunchApp(
+            mCmdLine->program().c_str(),
+            mCmdLine->command_line_string().c_str(), mLaunchOptions->env_map,
+            mProcessType, mEnableSandboxLogging, &handle)) {
+      EnvironmentLog("MOZ_PROCESS_LOG")
+          .print("==> process %d launched child process %d (%S)\n",
+                 base::GetCurrentProcId(), base::GetProcId(handle),
+                 mCmdLine->command_line_string().c_str());
+      return ProcessHandlePromise::CreateAndResolve(handle, __func__);
+    }
+    return ProcessHandlePromise::CreateAndReject(LaunchError{}, __func__);
+  }
+#  endif  // defined(MOZ_SANDBOX)
+
+  if (!base::LaunchApp(mCmdLine.ref(), *mLaunchOptions, &handle)) {
+    return ProcessHandlePromise::CreateAndReject(LaunchError{}, __func__);
+  }
+  return ProcessHandlePromise::CreateAndResolve(handle, __func__);
+}
+
+bool WindowsProcessLauncher::DoFinishLaunch() {
+  if (!BaseProcessLauncher::DoFinishLaunch()) {
+    return false;
   }
 
-#else  // goes with defined(OS_POSIX)
-#  error Sorry
-#endif  // defined(OS_POSIX)
+#  ifdef MOZ_SANDBOX
+  // We need to be able to duplicate handles to some types of non-sandboxed
+  // child processes.
+  switch (mProcessType) {
+    case GeckoProcessType_Default:
+      MOZ_CRASH("shouldn't be launching a parent process");
+    case GeckoProcessType_Plugin:
+    case GeckoProcessType_IPDLUnitTest:
+      // No handle duplication necessary.
+      break;
+    default:
+      if (!SandboxBroker::AddTargetPeer(mResults.mHandle)) {
+        NS_WARNING("Failed to add child process as target peer.");
+      }
+      break;
+  }
+#  endif  // MOZ_SANDBOX
 
-  MOZ_ASSERT(process);
-  // NB: on OS X, we block much longer than we need to in order to
-  // reach this call, waiting for the child process's task_t.  The
-  // best way to fix that is to refactor this file, hard.
-#if defined(MOZ_WIDGET_COCOA)
-  mChildTask = child_task;
-#endif  // defined(MOZ_WIDGET_COCOA)
-
-  if (!OpenPrivilegedHandle(base::GetProcId(process))
-#ifdef XP_WIN
-      // If we failed in opening the process handle, try harder by duplicating
-      // one.
-      && !::DuplicateHandle(::GetCurrentProcess(), process,
-                            ::GetCurrentProcess(), &mChildProcessHandle,
-                            PROCESS_DUP_HANDLE | PROCESS_TERMINATE |
-                                PROCESS_QUERY_INFORMATION | PROCESS_VM_READ |
-                                SYNCHRONIZE,
-                            FALSE, 0)
+  return true;
+}
 #endif  // XP_WIN
-  ) {
-    MOZ_CRASH("cannot open handle to child process");
+
+RefPtr<ProcessLaunchPromise> BaseProcessLauncher::FinishLaunch() {
+  if (!DoFinishLaunch()) {
+    return ProcessLaunchPromise::CreateAndReject(LaunchError{}, __func__);
   }
 
+  MOZ_DIAGNOSTIC_ASSERT(mResults.mHandle);
+
   CrashReporter::RegisterChildCrashAnnotationFileDescriptor(
-      base::GetProcId(process), crashAnnotationReadPipe.forget());
+      base::GetProcId(mResults.mHandle), mCrashAnnotationReadPipe.forget());
 
-  {
-    Monitor2AutoLock lock(mMonitor);
-    // This runs on a launch thread, but the OnChannel{Connected,Error}
-    // callbacks run on the I/O thread, so it's possible that the state already
-    // advanced beyond PROCESS_CREATED.
-    if (mProcessState < PROCESS_CREATED) {
-      mProcessState = PROCESS_CREATED;
-    }
-    lock.Signal();
-  }
+  Telemetry::AccumulateTimeDelta(Telemetry::CHILD_PROCESS_LAUNCH_MS,
+                                 mStartTimeStamp);
 
-  mLaunchOptions = nullptr;
-
-  Telemetry::AccumulateTimeDelta(Telemetry::CHILD_PROCESS_LAUNCH_MS, startTS);
-
-  // Warning: resolving the promise allows `this` to be deleted.
-  mHandlePromise->Resolve(process, __func__);
-  return true;
+  return ProcessLaunchPromise::CreateAndResolve(mResults, __func__);
 }
 
 bool GeckoChildProcessHost::OpenPrivilegedHandle(base::ProcessId aPid) {
@@ -1311,8 +1532,7 @@ void GeckoChildProcessHost::OnChannelError() {
   // FIXME/bug 773925: save up this error for the next listener.
 }
 
-RefPtr<GeckoChildProcessHost::HandlePromise>
-GeckoChildProcessHost::WhenProcessHandleReady() {
+RefPtr<ProcessHandlePromise> GeckoChildProcessHost::WhenProcessHandleReady() {
   MOZ_ASSERT(mHandlePromise != nullptr);
   return mHandlePromise;
 }
@@ -1325,10 +1545,10 @@ void GeckoChildProcessHost::GetQueuedMessages(std::queue<IPC::Message>& queue) {
 }
 
 #ifdef MOZ_WIDGET_ANDROID
-void GeckoChildProcessHost::LaunchAndroidService(
+void AndroidProcessLauncher::LaunchAndroidService(
     const char* type, const std::vector<std::string>& argv,
     const base::file_handle_mapping_vector& fds_to_remap,
-    ProcessHandle* process_handle) {
+    base::ProcessHandle* process_handle) {
   MOZ_RELEASE_ASSERT((2 <= fds_to_remap.size()) && (fds_to_remap.size() <= 5));
   JNIEnv* const env = mozilla::jni::GetEnvForThread();
   MOZ_ASSERT(env);
@@ -1422,3 +1642,44 @@ bool GeckoChildProcessHost::StartMacSandbox(int aArgc, char** aArgv,
 }
 
 #endif /* XP_MACOSX && MOZ_SANDBOX */
+
+/* static */
+void GeckoChildProcessHost::GetAll(const GeckoProcessCallback& aCallback) {
+  StaticMutexAutoLock lock(sMutex);
+  for (GeckoChildProcessHost* gp = sGeckoChildProcessHosts->getFirst(); gp;
+       gp = static_cast<mozilla::LinkedListElement<GeckoChildProcessHost>*>(gp)
+                ->getNext()) {
+    aCallback(gp);
+  }
+}
+
+RefPtr<ProcessLaunchPromise> BaseProcessLauncher::Launch(
+    GeckoChildProcessHost* aHost) {
+  AssertIOThread();
+
+  // Initializing the channel needs to happen on the I/O thread, but everything
+  // else can run on the launcher thread (or pool), to avoid blocking IPC
+  // messages.
+  //
+  // We avoid passing the host to the launcher thread to reduce the chances of
+  // data races with the IO thread (where e.g. OnChannelConnected may run
+  // concurrently). The pool currently needs access to the channel, which is not
+  // great.
+  //
+  // It's also unfortunate that we need to work with raw pointers to both the
+  // host and the channel. The assumption here is that the host (and therefore
+  // the channel) are never torn down until the return promise is resolved or
+  // rejected.
+  aHost->InitializeChannel();
+  mChannel = aHost->GetChannel();
+  if (!mChannel) {
+    return ProcessLaunchPromise::CreateAndReject(LaunchError{}, __func__);
+  }
+  mChannelId = aHost->GetChannelId();
+
+  return InvokeAsync(mLaunchThread, this, __func__,
+                     &BaseProcessLauncher::PerformAsyncLaunch);
+}
+
+}  // namespace ipc
+}  // namespace mozilla
diff --git a/ipc/glue/GeckoChildProcessHost.h b/ipc/glue/GeckoChildProcessHost.h
index 8553dd16b9..1098405979 100644
--- a/ipc/glue/GeckoChildProcessHost.h
+++ b/ipc/glue/GeckoChildProcessHost.h
@@ -12,6 +12,7 @@
 
 #include "mozilla/ipc/FileDescriptor.h"
 #include "mozilla/Atomics.h"
+#include "mozilla/LinkedList.h"
 #include "mozilla/Monitor2.h"
 #include "mozilla/MozPromise.h"
 #include "mozilla/StaticPtr.h"
@@ -35,7 +36,24 @@ typedef _MacSandboxInfo MacSandboxInfo;
 namespace mozilla {
 namespace ipc {
 
-class GeckoChildProcessHost : public ChildProcessHost {
+struct LaunchError {};
+typedef mozilla::MozPromise<base::ProcessHandle, LaunchError, false>
+    ProcessHandlePromise;
+
+struct LaunchResults {
+  base::ProcessHandle mHandle = 0;
+#ifdef XP_MACOSX
+  task_t mChildTask = MACH_PORT_NULL;
+#endif
+#if defined(XP_WIN) && defined(MOZ_SANDBOX)
+  RefPtr<AbstractSandboxBroker> mSandboxBroker;
+#endif
+};
+typedef mozilla::MozPromise<LaunchResults, LaunchError, false>
+    ProcessLaunchPromise;
+
+class GeckoChildProcessHost : public ChildProcessHost,
+                              public LinkedListElement<GeckoChildProcessHost> {
  protected:
   typedef mozilla::Monitor2 Monitor2;
   typedef std::vector<std::string> StringVector;
@@ -90,14 +108,9 @@ class GeckoChildProcessHost : public ChildProcessHost {
   virtual void OnChannelError() override;
   virtual void GetQueuedMessages(std::queue<IPC::Message>& queue) override;
 
-  struct LaunchError {};
-  template <typename T>
-  using LaunchPromise = mozilla::MozPromise<T, LaunchError, /* excl: */ false>;
-  using HandlePromise = LaunchPromise<base::ProcessHandle>;
-
   // Resolves to the process handle when it's available (see
   // LaunchAndWaitForProcessHandle); use with AsyncLaunch.
-  RefPtr<HandlePromise> WhenProcessHandleReady();
+  RefPtr<ProcessHandlePromise> WhenProcessHandleReady();
 
   virtual void InitializeChannel();
 
@@ -105,6 +118,7 @@ class GeckoChildProcessHost : public ChildProcessHost {
 
   using ChildProcessHost::TakeChannel;
   IPC::Channel* GetChannel() { return channelp(); }
+  std::wstring GetChannelId() { return channel_id(); }
 
   // Returns a "borrowed" handle to the child process - the handle returned
   // by this function must not be closed by the caller.
@@ -152,10 +166,17 @@ class GeckoChildProcessHost : public ChildProcessHost {
     return MacSandboxType_Utility;
   };
 #endif
+  typedef std::function<void(GeckoChildProcessHost*)> GeckoProcessCallback;
+
+  // Iterates over all instances and calls aCallback with each one of them.
+  // This method will lock any addition/removal of new processes
+  // so you need to make sure the callback is as fast as possible.
+  static void GetAll(const GeckoProcessCallback& aCallback);
+
+  friend class BaseProcessLauncher;
 
  protected:
   ~GeckoChildProcessHost();
-
   GeckoProcessType mProcessType;
   bool mIsFileContent;
   Monitor2 mMonitor;
@@ -183,8 +204,6 @@ class GeckoChildProcessHost : public ChildProcessHost {
     PROCESS_ERROR
   } mProcessState;
 
-  static int32_t mChildCounter;
-
   void PrepareLaunch();
 
 #ifdef XP_WIN
@@ -203,7 +222,7 @@ class GeckoChildProcessHost : public ChildProcessHost {
 #if defined(OS_MACOSX)
   task_t mChildTask;
 #endif
-  RefPtr<HandlePromise::Private> mHandlePromise;
+  RefPtr<ProcessHandlePromise> mHandlePromise;
 
   bool OpenPrivilegedHandle(base::ProcessId aPid);
 
@@ -225,20 +244,8 @@ class GeckoChildProcessHost : public ChildProcessHost {
  private:
   DISALLOW_EVIL_CONSTRUCTORS(GeckoChildProcessHost);
 
-  // Does the actual work for AsyncLaunch; run in a thread pool
-  // (or, on Windows, a dedicated thread).
-  bool PerformAsyncLaunch(StringVector aExtraOpts);
-
-  // Called on the I/O thread; creates channel, dispatches
-  // PerformAsyncLaunch, and consolidates error handling.
-  void RunPerformAsyncLaunch(StringVector aExtraOpts);
-
-  static BinPathType GetPathToBinary(FilePath& exePath,
-                                     GeckoProcessType processType);
-
-  // The buffer is passed to preserve its lifetime until we are done
-  // with launching the sub-process.
-  void GetChildLogName(const char* origLogName, nsACString& buffer);
+  // Removes the instance from sGeckoChildProcessHosts
+  void RemoveFromProcessList();
 
   // In between launching the subprocess and handing off its IPC
   // channel, there's a small window of time in which *we* might still
@@ -249,21 +256,15 @@ class GeckoChildProcessHost : public ChildProcessHost {
   // FIXME/cjones: this strongly indicates bad design.  Shame on us.
   std::queue<IPC::Message> mQueue;
 
-  // Set this up before we're called from a different thread.
-#if defined(OS_LINUX)
+  // Linux-Only. Set this up before we're called from a different thread.
   nsCString mTmpDirName;
-#endif
 
   mozilla::Atomic<bool> mDestroying;
 
   static uint32_t sNextUniqueID;
-
-#if defined(MOZ_WIDGET_ANDROID)
-  void LaunchAndroidService(
-      const char* type, const std::vector<std::string>& argv,
-      const base::file_handle_mapping_vector& fds_to_remap,
-      ProcessHandle* process_handle);
-#endif  // defined(MOZ_WIDGET_ANDROID)
+  static StaticAutoPtr<LinkedList<GeckoChildProcessHost>>
+      sGeckoChildProcessHosts;
+  static StaticMutex sMutex;
 };
 
 } /* namespace ipc */
diff --git a/ipc/glue/IPCMessageUtils.h b/ipc/glue/IPCMessageUtils.h
index 806455b273..3d573a714d 100644
--- a/ipc/glue/IPCMessageUtils.h
+++ b/ipc/glue/IPCMessageUtils.h
@@ -628,7 +628,7 @@ struct ParamTraits<FallibleTArray<E>> {
     nsTArray<E> temp;
     if (!ReadParam(aMsg, aIter, &temp)) return false;
 
-    aResult->SwapElements(temp);
+    *aResult = std::move(temp);
     return true;
   }
 
diff --git a/ipc/glue/Neutering.h b/ipc/glue/Neutering.h
index c44c6f5c58..3ebff1bda0 100644
--- a/ipc/glue/Neutering.h
+++ b/ipc/glue/Neutering.h
@@ -5,7 +5,6 @@
 #ifndef mozilla_ipc_Neutering_h
 #define mozilla_ipc_Neutering_h
 
-#include "mozilla/GuardObjects.h"
 
 /**
  * This header declares RAII wrappers for Window neutering. See
@@ -23,7 +22,7 @@ namespace ipc {
  */
 class MOZ_RAII NeuteredWindowRegion {
  public:
-  explicit NeuteredWindowRegion(bool aDoNeuter MOZ_GUARD_OBJECT_NOTIFIER_PARAM);
+  explicit NeuteredWindowRegion(bool aDoNeuter);
   ~NeuteredWindowRegion();
 
   /**
@@ -33,7 +32,6 @@ class MOZ_RAII NeuteredWindowRegion {
   void PumpOnce();
 
  private:
-  MOZ_DECL_USE_GUARD_OBJECT_NOTIFIER
   bool mNeuteredByThis;
 };
 
@@ -45,23 +43,21 @@ class MOZ_RAII NeuteredWindowRegion {
  */
 class MOZ_RAII DeneuteredWindowRegion {
  public:
-  explicit DeneuteredWindowRegion(MOZ_GUARD_OBJECT_NOTIFIER_ONLY_PARAM);
+  explicit DeneuteredWindowRegion();
   ~DeneuteredWindowRegion();
 
  private:
-  MOZ_DECL_USE_GUARD_OBJECT_NOTIFIER
   bool mReneuter;
 };
 
 class MOZ_RAII SuppressedNeuteringRegion {
  public:
-  explicit SuppressedNeuteringRegion(MOZ_GUARD_OBJECT_NOTIFIER_ONLY_PARAM);
+  explicit SuppressedNeuteringRegion();
   ~SuppressedNeuteringRegion();
 
   static inline bool IsNeuteringSuppressed() { return sSuppressNeutering; }
 
  private:
-  MOZ_DECL_USE_GUARD_OBJECT_NOTIFIER
   bool mReenable;
 
   static bool sSuppressNeutering;
diff --git a/ipc/glue/ProtocolUtils.cpp b/ipc/glue/ProtocolUtils.cpp
index 03e4e01bcd..378ec357c9 100644
--- a/ipc/glue/ProtocolUtils.cpp
+++ b/ipc/glue/ProtocolUtils.cpp
@@ -8,6 +8,7 @@
 #ifdef OS_POSIX
 #  include <errno.h>
 #endif
+#include <type_traits>
 
 #include "mozilla/IntegerPrintfMacros.h"
 
@@ -42,10 +43,10 @@ namespace mozilla {
 #if defined(XP_WIN)
 // Generate RAII classes for LPTSTR and PSECURITY_DESCRIPTOR.
 MOZ_TYPE_SPECIFIC_SCOPED_POINTER_TEMPLATE(ScopedLPTStr,
-                                          RemovePointer<LPTSTR>::Type,
+                                          std::remove_pointer_t<LPTSTR>,
                                           ::LocalFree)
 MOZ_TYPE_SPECIFIC_SCOPED_POINTER_TEMPLATE(
-    ScopedPSecurityDescriptor, RemovePointer<PSECURITY_DESCRIPTOR>::Type,
+    ScopedPSecurityDescriptor, std::remove_pointer_t<PSECURITY_DESCRIPTOR>,
     ::LocalFree)
 #endif
 
diff --git a/ipc/glue/WindowsMessageLoop.cpp b/ipc/glue/WindowsMessageLoop.cpp
index a4825702fd..06ae484d43 100644
--- a/ipc/glue/WindowsMessageLoop.cpp
+++ b/ipc/glue/WindowsMessageLoop.cpp
@@ -13,6 +13,7 @@
 #include "WinUtils.h"
 
 #include "mozilla/ArrayUtils.h"
+#include "mozilla/dom/JSExecutionManager.h"
 #include "mozilla/ipc/ProtocolUtils.h"
 #include "mozilla/PaintTracker.h"
 #include "mozilla/UniquePtr.h"
@@ -793,11 +794,9 @@ static void StopNeutering() {
   MessageChannel::SetIsPumpingMessages(false);
 }
 
-NeuteredWindowRegion::NeuteredWindowRegion(
-    bool aDoNeuter MOZ_GUARD_OBJECT_NOTIFIER_PARAM_IN_IMPL)
+NeuteredWindowRegion::NeuteredWindowRegion(bool aDoNeuter)
     : mNeuteredByThis(!gWindowHook && aDoNeuter &&
                       XRE_UseNativeEventProcessing()) {
-  MOZ_GUARD_OBJECT_NOTIFIER_INIT;
   if (mNeuteredByThis) {
     StartNeutering();
   }
@@ -825,10 +824,8 @@ void NeuteredWindowRegion::PumpOnce() {
   ::PeekMessageW(&msg, nullptr, 0, 0, PM_NOREMOVE);
 }
 
-DeneuteredWindowRegion::DeneuteredWindowRegion(
-    MOZ_GUARD_OBJECT_NOTIFIER_ONLY_PARAM_IN_IMPL)
+DeneuteredWindowRegion::DeneuteredWindowRegion()
     : mReneuter(gWindowHook != NULL) {
-  MOZ_GUARD_OBJECT_NOTIFIER_INIT;
   if (mReneuter) {
     StopNeutering();
   }
@@ -840,10 +837,8 @@ DeneuteredWindowRegion::~DeneuteredWindowRegion() {
   }
 }
 
-SuppressedNeuteringRegion::SuppressedNeuteringRegion(
-    MOZ_GUARD_OBJECT_NOTIFIER_ONLY_PARAM_IN_IMPL)
+SuppressedNeuteringRegion::SuppressedNeuteringRegion()
     : mReenable(::gUIThreadId == ::GetCurrentThreadId() && ::gWindowHook) {
-  MOZ_GUARD_OBJECT_NOTIFIER_INIT;
   if (mReenable) {
     MOZ_ASSERT(!sSuppressNeutering);
     sSuppressNeutering = true;
@@ -1065,6 +1060,10 @@ bool MessageChannel::WaitForSyncNotify(bool aHandleWindowsMessages) {
 bool MessageChannel::WaitForInterruptNotify() {
   mMonitor->AssertCurrentThreadOwns();
 
+  // Receiving the interrupt notification may require JS to execute on a
+  // worker.
+  dom::AutoYieldJSThreadExecution yield;
+
   if (!gUIThreadId) {
     mozilla::ipc::windows::InitUIThread();
   }
diff --git a/ipc/mscom/InterceptorLog.cpp b/ipc/mscom/InterceptorLog.cpp
index 3dca190232..d1c888f7c7 100644
--- a/ipc/mscom/InterceptorLog.cpp
+++ b/ipc/mscom/InterceptorLog.cpp
@@ -427,7 +427,7 @@ void Logger::Flush() {
   nsTArray<nsCString> linesToWrite;
   {  // Scope for lock
     MutexAutoLock lock(mMutex);
-    linesToWrite.SwapElements(mEntries);
+    linesToWrite = std::move(mEntries);
   }
 
   for (uint32_t i = 0, len = linesToWrite.Length(); i < len; ++i) {
diff --git a/ipc/mscom/ProxyStream.cpp b/ipc/mscom/ProxyStream.cpp
index 72f69ec650..90a827c306 100644
--- a/ipc/mscom/ProxyStream.cpp
+++ b/ipc/mscom/ProxyStream.cpp
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-#include "mozilla/Move.h"
+#include <utility>
 #if defined(ACCESSIBILITY)
 #  include "HandlerData.h"
 #  include "mozilla/a11y/Platform.h"
diff --git a/ipc/mscom/Registration.cpp b/ipc/mscom/Registration.cpp
index 38aa50ab87..8382f5d44e 100644
--- a/ipc/mscom/Registration.cpp
+++ b/ipc/mscom/Registration.cpp
@@ -14,7 +14,6 @@
 #include "mozilla/ArrayUtils.h"
 #include "mozilla/Assertions.h"
 #include "mozilla/Move.h"
-#include "mozilla/Pair.h"
 #include "mozilla/RefPtr.h"
 #include "mozilla/StaticPtr.h"
 #include "mozilla/Vector.h"
@@ -460,17 +459,17 @@ void RegisteredProxy::DeleteFromRegistry(RegisteredProxy* aProxy) {
 
 #if defined(MOZILLA_INTERNAL_API)
 
-static StaticAutoPtr<Vector<Pair<const ArrayData*, size_t>>> sArrayData;
+static StaticAutoPtr<Vector<std::pair<const ArrayData*, size_t>>> sArrayData;
 
 void RegisterArrayData(const ArrayData* aArrayData, size_t aLength) {
   AutoCriticalSection lock(GetMutex());
 
   if (!sArrayData) {
-    sArrayData = new Vector<Pair<const ArrayData*, size_t>>();
+    sArrayData = new Vector<std::pair<const ArrayData*, size_t>>();
     ClearOnShutdown(&sArrayData, ShutdownPhase::ShutdownThreads);
   }
 
-  MOZ_ALWAYS_TRUE(sArrayData->emplaceBack(MakePair(aArrayData, aLength)));
+  MOZ_ALWAYS_TRUE(sArrayData->emplaceBack(std::make_pair(aArrayData, aLength)));
 }
 
 const ArrayData* FindArrayData(REFIID aIid, ULONG aMethodIndex) {
@@ -481,9 +480,9 @@ const ArrayData* FindArrayData(REFIID aIid, ULONG aMethodIndex) {
   }
 
   for (auto&& data : *sArrayData) {
-    for (size_t innerIdx = 0, innerLen = data.second(); innerIdx < innerLen;
+    for (size_t innerIdx = 0, innerLen = data.second; innerIdx < innerLen;
          ++innerIdx) {
-      const ArrayData* array = data.first();
+      const ArrayData* array = data.first;
       if (aMethodIndex == array[innerIdx].mMethodIndex &&
           IsInterfaceEqualToOrInheritedFrom(aIid, array[innerIdx].mIid,
                                             aMethodIndex)) {
diff --git a/layout/base/AutoProfilerStyleMarker.h b/layout/base/AutoProfilerStyleMarker.h
index 1559acc8cc..1de7422e5e 100644
--- a/layout/base/AutoProfilerStyleMarker.h
+++ b/layout/base/AutoProfilerStyleMarker.h
@@ -18,7 +18,7 @@ class MOZ_RAII AutoProfilerStyleMarker {
   explicit AutoProfilerStyleMarker(UniqueProfilerBacktrace aCause,
                                    const Maybe<nsID>& aDocShellId,
                                    const Maybe<uint32_t>& aDocShellHistoryId)
-      : mActive(profiler_is_active()),
+      : mActive(profiler_can_accept_markers()),
         mStartTime(TimeStamp::Now()),
         mCause(std::move(aCause)),
         mDocShellId(aDocShellId),
@@ -37,11 +37,11 @@ class MOZ_RAII AutoProfilerStyleMarker {
       return;
     }
     ServoTraversalStatistics::sActive = false;
-    profiler_add_marker("Styles", JS::ProfilingCategoryPair::LAYOUT,
-                        MakeUnique<StyleMarkerPayload>(
-                            mStartTime, TimeStamp::Now(), std::move(mCause),
-                            ServoTraversalStatistics::sSingleton, mDocShellId,
-                            mDocShellHistoryId));
+    PROFILER_ADD_MARKER_WITH_PAYLOAD(
+        "Styles", LAYOUT, StyleMarkerPayload,
+        (mStartTime, TimeStamp::Now(), std::move(mCause),
+         ServoTraversalStatistics::sSingleton, mDocShellId,
+         mDocShellHistoryId));
   }
 
  private:
diff --git a/layout/base/FrameProperties.h b/layout/base/FrameProperties.h
index 0bbad446aa..7f255c8c33 100644
--- a/layout/base/FrameProperties.h
+++ b/layout/base/FrameProperties.h
@@ -261,8 +261,7 @@ class FrameProperties {
    * Remove and destroy all property values for the frame.
    */
   void RemoveAll(const nsIFrame* aFrame) {
-    nsTArray<PropertyValue> toDelete;
-    toDelete.SwapElements(mProperties);
+    nsTArray<PropertyValue> toDelete = std::move(mProperties);
     for (auto& prop : toDelete) {
       prop.DestroyValueFor(aFrame);
     }
diff --git a/layout/base/PresShell.cpp b/layout/base/PresShell.cpp
index e174a7407c..bbd44fbae2 100644
--- a/layout/base/PresShell.cpp
+++ b/layout/base/PresShell.cpp
@@ -600,11 +600,10 @@ void PresShell::DirtyRootsList::Remove(nsIFrame* aFrame) {
 nsIFrame* PresShell::DirtyRootsList::PopShallowestRoot() {
   // List is sorted in order of decreasing depth, so there are no deeper
   // frames than the last one.
-  const FrameAndDepth& lastFAD = mList.LastElement();
+  const FrameAndDepth& lastFAD = mList.PopLastElement();
   nsIFrame* frame = lastFAD.mFrame;
   // We don't expect frame to change depths.
   MOZ_ASSERT(frame->GetDepthInFrameTree() == lastFAD.mDepth);
-  mList.RemoveLastElement();
   return frame;
 }
 
@@ -5552,8 +5551,8 @@ void PresShell::RebuildApproximateFrameVisibilityDisplayList(
 
   // Remove the entries of the mApproximatelyVisibleFrames hashtable and put
   // them in oldApproxVisibleFrames.
-  VisibleFrames oldApproximatelyVisibleFrames;
-  mApproximatelyVisibleFrames.SwapElements(oldApproximatelyVisibleFrames);
+  VisibleFrames oldApproximatelyVisibleFrames =
+      std::move(mApproximatelyVisibleFrames);
 
   MarkFramesInListApproximatelyVisible(aList);
 
@@ -5704,8 +5703,8 @@ void PresShell::RebuildApproximateFrameVisibility(
 
   // Remove the entries of the mApproximatelyVisibleFrames hashtable and put
   // them in oldApproximatelyVisibleFrames.
-  VisibleFrames oldApproximatelyVisibleFrames;
-  mApproximatelyVisibleFrames.SwapElements(oldApproximatelyVisibleFrames);
+  VisibleFrames oldApproximatelyVisibleFrames =
+      std::move(mApproximatelyVisibleFrames);
 
   nsRect vis(nsPoint(0, 0), rootFrame->GetSize());
   if (aRect) {
diff --git a/layout/base/nsBidiPresUtils.cpp b/layout/base/nsBidiPresUtils.cpp
index a58591c211..27430b0a95 100644
--- a/layout/base/nsBidiPresUtils.cpp
+++ b/layout/base/nsBidiPresUtils.cpp
@@ -451,7 +451,7 @@ struct MOZ_STACK_CLASS BidiParagraphData {
     MOZ_ASSERT(mEmbeddingStack.Length(), "embedding/override underflow");
     MOZ_ASSERT(aCh == mEmbeddingStack.LastElement());
     AppendPopChar(aCh);
-    mEmbeddingStack.TruncateLength(mEmbeddingStack.Length() - 1);
+    mEmbeddingStack.RemoveLastElement();
   }
 
   void ClearBidiControls() {
diff --git a/layout/base/nsPresArena.cpp b/layout/base/nsPresArena.cpp
index ae23a38199..f757e895d3 100644
--- a/layout/base/nsPresArena.cpp
+++ b/layout/base/nsPresArena.cpp
@@ -25,12 +25,10 @@ template <size_t ArenaSize, typename ObjectId, size_t ObjectIdCount>
 nsPresArena<ArenaSize, ObjectId, ObjectIdCount>::~nsPresArena() {
 #if defined(MOZ_HAVE_MEM_CHECKS)
   for (FreeList* entry = mFreeLists; entry != ArrayEnd(mFreeLists); ++entry) {
-    nsTArray<void*>::index_type len;
-    while ((len = entry->mEntries.Length())) {
-      void* result = entry->mEntries.ElementAt(len - 1);
-      entry->mEntries.RemoveElementAt(len - 1);
+    for (void* result : entry->mEntries) {
       MOZ_MAKE_MEM_UNDEFINED(result, entry->mEntrySize);
     }
+    entry->mEntries.Clear();
   }
 #endif
 }
diff --git a/layout/base/nsRefreshDriver.cpp b/layout/base/nsRefreshDriver.cpp
index 2b83074bf9..9603b087a7 100644
--- a/layout/base/nsRefreshDriver.cpp
+++ b/layout/base/nsRefreshDriver.cpp
@@ -1213,8 +1213,8 @@ void nsRefreshDriver::DispatchVisualViewportResizeEvents() {
   // We're taking a hint from scroll events and only dispatch the current set
   // of queued resize events. If additional events are posted in response to
   // the current events being dispatched, we'll dispatch them on the next tick.
-  VisualViewportResizeEventArray events;
-  events.SwapElements(mVisualViewportResizeEvents);
+  VisualViewportResizeEventArray events =
+      std::move(mVisualViewportResizeEvents);
   for (auto& event : events) {
     event->Run();
   }
@@ -1235,8 +1235,7 @@ void nsRefreshDriver::DispatchScrollEvents() {
   // However, dispatching a scroll event can potentially cause more scroll
   // events to be posted, so we move the initial set into a temporary array
   // first. (Newly posted scroll events will be dispatched on the next tick.)
-  ScrollEventArray events;
-  events.SwapElements(mScrollEvents);
+  ScrollEventArray events = std::move(mScrollEvents);
   for (auto& event : events) {
     event->Run();
   }
@@ -1253,8 +1252,8 @@ void nsRefreshDriver::DispatchVisualViewportScrollEvents() {
   // However, dispatching a scroll event can potentially cause more scroll
   // events to be posted, so we move the initial set into a temporary array
   // first. (Newly posted scroll events will be dispatched on the next tick.)
-  VisualViewportScrollEventArray events;
-  events.SwapElements(mVisualViewportScrollEvents);
+  VisualViewportScrollEventArray events =
+      std::move(mVisualViewportScrollEvents);
   for (auto& event : events) {
     event->Run();
   }
@@ -1679,6 +1678,14 @@ void nsRefreshDriver::RunFrameRequestCallbacks(TimeStamp aNowTime) {
         mozilla::dom::Performance* perf = innerWindow->GetPerformance();
         if (perf) {
           timeStamp = perf->GetDOMTiming()->TimeStampToDOMHighRes(aNowTime);
+          // 0 is an inappropriate mixin for this this area; however CSS
+          // Animations needs to have it's Time Reduction Logic refactored, so
+          // it's currently only clamping for RFP mode. RFP mode gives a much
+          // lower time precision, so we accept the security leak here for now
+          if (!perf->IsSystemPrincipal()) {
+            timeStamp = nsRFPService::ReduceTimePrecisionAsMSecs(
+                timeStamp, 0, TimerPrecisionType::RFPOnly);
+          }
         }
         // else window is partially torn down already
       }
@@ -1863,8 +1870,7 @@ void nsRefreshDriver::Tick(VsyncId aId, TimeStamp aNowTime) {
     nsLayoutUtils::UpdateDisplayPortMarginsFromPendingMessages();
   }
 
-  AutoTArray<nsCOMPtr<nsIRunnable>, 16> earlyRunners;
-  earlyRunners.SwapElements(mEarlyRunners);
+  AutoTArray<nsCOMPtr<nsIRunnable>, 16> earlyRunners = std::move(mEarlyRunners);
   for (auto& runner : earlyRunners) {
     runner->Run();
   }
diff --git a/layout/base/tests/bug613807-1.html b/layout/base/tests/bug613807-1.html
index 404fa212cf..79592fed7a 100644
--- a/layout/base/tests/bug613807-1.html
+++ b/layout/base/tests/bug613807-1.html
@@ -25,7 +25,7 @@
       return rval;
     };
     function addLoadEvent(func) {
-      var existing = window["onload"];
+      var existing = window.onload;
       var regfunc = existing;
       if (!(typeof(existing) == 'function'
             && typeof(existing.callStack) == "object"
@@ -34,7 +34,7 @@
         if (typeof(existing) == 'function') {
           regfunc.callStack.push(existing);
         }
-        window["onload"] = regfunc;
+        window.onload = regfunc;
       }
       regfunc.callStack.push(func);
     };
diff --git a/layout/base/tests/selection-utils.js b/layout/base/tests/selection-utils.js
index c97f533755..e3a3ddb87d 100644
--- a/layout/base/tests/selection-utils.js
+++ b/layout/base/tests/selection-utils.js
@@ -24,15 +24,15 @@ function dragSelectPointsWithData() {
   var x2 = arguments[4];
   var y2 = arguments[5];
   dir = x2 > x1 ? 1 : -1;
-  event["type"] = "mousedown";
+  event.type = "mousedown";
   synthesizeMouse(e, x1, y1, event);
-  event["type"] = "mousemove";
+  event.type = "mousemove";
   synthesizeMouse(e, x1 + dir, y1, event);
   for (var i = 6; i < arguments.length; ++i) {
     synthesizeMouse(e, arguments[i], y1, event);
   }
   synthesizeMouse(e, x2 - dir, y2, event);
-  event["type"] = "mouseup";
+  event.type = "mouseup";
   synthesizeMouse(e, x2, y2, event);
 }
 
diff --git a/layout/base/tests/test_bug399284.html b/layout/base/tests/test_bug399284.html
index dcfd6e9bdb..452ab7c77d 100644
--- a/layout/base/tests/test_bug399284.html
+++ b/layout/base/tests/test_bug399284.html
@@ -104,8 +104,7 @@ function testFontSize(frame)
 {
     var iframeDoc = SpecialPowers.wrap($(frame)).contentDocument;
     var size = parseInt(iframeDoc.defaultView.
-                getComputedStyle(iframeDoc.getElementById("testPara"), 
-                                 null).
+                getComputedStyle(iframeDoc.getElementById("testPara")).
                 getPropertyValue("font-size"));
     ok(size > 0, "font size assigned for " + frame);
 }
diff --git a/layout/build/components.conf b/layout/build/components.conf
index 3b88b9994d..e017f8ba61 100644
--- a/layout/build/components.conf
+++ b/layout/build/components.conf
@@ -87,6 +87,7 @@ Classes = [
         'headers': ['mozilla/dom/BlobURL.h'],
     },
     {
+        'js_name': 'cpmm',
         'cid': '{fe0ff7c3-8e97-448b-9a8a-86afdb9fbbb6}',
         'contract_ids': ['@mozilla.org/childprocessmessagemanager;1'],
         'legacy_constructor': 'CreateChildMessageManager',
@@ -148,16 +149,20 @@ Classes = [
         'headers': ['nsStructuredCloneContainer.h'],
     },
     {
+        'js_name': 'DOMRequest',
         'cid': '{3160e271-138d-4cc7-9d63-6429f16957c7}',
         'contract_ids': ['@mozilla.org/dom/dom-request-service;1'],
+        'interfaces': ['nsIDOMRequestService'],
         'singleton': True,
         'type': 'mozilla::dom::DOMRequestService',
         'headers': ['mozilla/dom/DOMRequest.h'],
         'constructor': 'mozilla::dom::DOMRequestService::FactoryCreate',
     },
     {
+        'js_name': 'domStorageManager',
         'cid': '{656db07c-aa80-49e4-bce8-e431baae697d}',
         'contract_ids': ['@mozilla.org/dom/localStorage-manager;1'],
+        'interfaces': ['nsIDOMStorageManager', 'nsILocalStorageManager'],
         'legacy_constructor': 'LocalStorageManagerConstructor',
     },
     {
@@ -166,8 +171,10 @@ Classes = [
         'legacy_constructor': 'SessionStorageManagerConstructor',
     },
     {
+        'js_name': 'qms',
         'cid': '{5a75c25a-5e7e-4d90-8f7c-07eb15cc0aa8}',
         'contract_ids': ['@mozilla.org/dom/quota-manager-service;1'],
+        'interfaces': ['nsIQuotaManagerService'],
         'singleton': True,
         'type': 'mozilla::dom::quota::QuotaManagerService',
         'headers': ['mozilla/dom/quota/QuotaManagerService.h'],
@@ -189,8 +196,10 @@ Classes = [
         'constructor': 'mozilla::dom::WorkerDebuggerManager::GetInstance',
     },
     {
+        'js_name': 'els',
         'cid': '{baa34652-f1f1-4185-b224-244ee82a413a}',
         'contract_ids': ['@mozilla.org/eventlistenerservice;1'],
+        'interfaces': ['nsIEventListenerService'],
         'type': 'nsIEventListenerService',
     },
     {
@@ -200,8 +209,10 @@ Classes = [
         'headers': ['/caps/ExpandedPrincipal.h'],
     },
     {
+        'js_name': 'focus',
         'cid': '{cf7fd51f-aba2-44c1-9ff0-11f7508efcd4}',
         'contract_ids': ['@mozilla.org/focus-manager;1'],
+        'interfaces': ['nsIFocusManager'],
         'type': 'nsIFocusManager',
     },
     {
@@ -221,6 +232,7 @@ Classes = [
         'constructor': 'mozilla::dom::Geolocation::NonWindowSingleton',
     },
     {
+        'js_name': 'mm',
         'cid': '{130b016f-fad7-4526-bc7f-827dabf79265}',
         'contract_ids': ['@mozilla.org/globalmessagemanager;1'],
         'legacy_constructor': 'CreateGlobalMessageManager',
@@ -316,6 +328,7 @@ Classes = [
         'init_method': 'Init',
     },
     {
+        'js_name': 'ppmm',
         'cid': '{2a058404-fb85-44ec-8cfd-e8cbdc988dc1}',
         'contract_ids': ['@mozilla.org/parentprocessmessagemanager;1'],
         'legacy_constructor': 'CreateParentMessageManager',
@@ -373,8 +386,10 @@ Classes = [
         'headers': ['/dom/bindings/nsScriptError.h'],
     },
     {
+        'js_name': 'scriptSecurityManager',
         'cid': '{7ee2a4c0-4b93-17d3-ba18-0060b0f199a2}',
         'contract_ids': ['@mozilla.org/scriptsecuritymanager;1'],
+        'interfaces': ['nsIScriptSecurityManager'],
         'legacy_constructor': 'Construct_nsIScriptSecurityManager',
     },
     {
diff --git a/layout/generic/nsFrameList.h b/layout/generic/nsFrameList.h
index 0efd13fbd4..eb99bad582 100644
--- a/layout/generic/nsFrameList.h
+++ b/layout/generic/nsFrameList.h
@@ -488,6 +488,18 @@ class nsFrameList {
 
   class Iterator {
    public:
+    // It is disputable whether these type definitions are correct, since
+    // operator* doesn't return a reference at all. Also, the iterator_category
+    // can be at most std::input_iterator_tag (rather than
+    // std::bidrectional_iterator_tag, as it might seem), because it is a
+    // stashing iterator. See also, e.g.,
+    // https://stackoverflow.com/questions/50909701/what-should-be-iterator-category-for-a-stashing-iterator
+    using value_type = nsIFrame* const;
+    using pointer = value_type*;
+    using reference = value_type&;
+    using difference_type = ptrdiff_t;
+    using iterator_category = std::input_iterator_tag;
+
     Iterator(const nsFrameList& aList, nsIFrame* aCurrent)
         : mList(aList), mCurrent(aCurrent) {}
 
diff --git a/layout/generic/test/test_bug344830.html b/layout/generic/test/test_bug344830.html
index e97a71ae6e..f071ba85b6 100644
--- a/layout/generic/test/test_bug344830.html
+++ b/layout/generic/test/test_bug344830.html
@@ -22,7 +22,7 @@ https://bugzilla.mozilla.org/show_bug.cgi?id=344830
 
 /** Test for Bug 344830 **/
 function getSVG() {
- var embed = document.embeds["svg1"];
+ var embed = document.embeds.svg1;
  var svgDocument = embed.getSVGDocument();
  var element = svgDocument.getElementById("g1");
  ok(embed, "document.embeds[] works with SVG");
diff --git a/layout/generic/test/test_dynamic_reflow_root_disallowal.html b/layout/generic/test/test_dynamic_reflow_root_disallowal.html
index 7c06bf0d07..722ab714c0 100644
--- a/layout/generic/test/test_dynamic_reflow_root_disallowal.html
+++ b/layout/generic/test/test_dynamic_reflow_root_disallowal.html
@@ -626,7 +626,7 @@ https://bugzilla.mozilla.org/show_bug.cgi?id=1508420
     // and we'll probably want to remove this test function, along with the
     // IsXULBoxFrame() check that this test function is targeting in
     // ReflowInput::InitDynamicReflowRoot.
-    is(gFWindow.getComputedStyle(mozBox, "").display, "-moz-box",
+    is(gFWindow.getComputedStyle(mozBox).display, "-moz-box",
        "'display:-moz-box' should be honored and show up in computed style");
 
     let tweakFunc = function() {
diff --git a/layout/inspector/tests/test_getRelativeRuleLine.html b/layout/inspector/tests/test_getRelativeRuleLine.html
index 219b29fb83..0759aec56d 100644
--- a/layout/inspector/tests/test_getRelativeRuleLine.html
+++ b/layout/inspector/tests/test_getRelativeRuleLine.html
@@ -30,7 +30,7 @@
 
   let tests = [
     { sheetNo: 0, ruleNo: 0, lineNo: 1, columnNo: 1 },
-    { sheetNo: 1, ruleNo: 0, lineNo: 2, columnNo: 14 },
+    { sheetNo: 1, ruleNo: 0, lineNo: 2, columnNo: 5 },
     { sheetNo: 1, ruleNo: 1, lineNo: 8, columnNo: 5 },
     { sheetNo: 2, ruleNo: 0, lineNo: 1, columnNo: 1 },
     { sheetNo: 2, ruleNo: 1, lineNo: 0, columnNo: 1 },
diff --git a/layout/mathml/tests/test_bug553917.html b/layout/mathml/tests/test_bug553917.html
index 491865329c..09c4ab839b 100644
--- a/layout/mathml/tests/test_bug553917.html
+++ b/layout/mathml/tests/test_bug553917.html
@@ -78,13 +78,11 @@ https://bugzilla.mozilla.org/show_bug.cgi?id=553917
         if (name != "MMultiscriptsErrors") {
           var formatParams = g_errorInfo[name].args[idx];
           if (formatParams.length > 0) {
-            return g_bundl.formatStringFromName(name,formatParams);
-          } else {
-            return g_bundl.GetStringFromName(name);
+              return g_bundl.formatStringFromName(name,formatParams);
           }
-        } else {
-          return g_bundl.GetStringFromName(g_errorInfo[name].args[idx]);
+          return g_bundl.GetStringFromName(name);
         }
+        return g_bundl.GetStringFromName(g_errorInfo[name].args[idx]);
       }
     
     /** Checks the roll call to see if all expected error messages were present. */
diff --git a/layout/mathml/tests/test_bug827713-2.html b/layout/mathml/tests/test_bug827713-2.html
index 726f8b9370..52666379dd 100644
--- a/layout/mathml/tests/test_bug827713-2.html
+++ b/layout/mathml/tests/test_bug827713-2.html
@@ -37,9 +37,7 @@ https://bugzilla.mozilla.org/show_bug.cgi?id=553917
         if (name != "MMultiscriptsErrors") {
           return g_bundl.formatStringFromName(name,g_errorInfo[name].args[idx]);
         }
-        else {
-          return g_bundl.GetStringFromName(g_errorInfo[name].args[idx]);
-        }
+        return g_bundl.GetStringFromName(g_errorInfo[name].args[idx]);
       }
     
     /** Checks the roll call to see if all expected error messages were present. */
diff --git a/layout/painting/FrameLayerBuilder.cpp b/layout/painting/FrameLayerBuilder.cpp
index 2a3e665f86..26604c7328 100644
--- a/layout/painting/FrameLayerBuilder.cpp
+++ b/layout/painting/FrameLayerBuilder.cpp
@@ -1876,7 +1876,7 @@ struct MaskLayerUserData : public LayerUserData {
     mScaleY = aOther.mScaleY;
     mOffset = aOther.mOffset;
     mAppUnitsPerDevPixel = aOther.mAppUnitsPerDevPixel;
-    mRoundedClipRects.SwapElements(aOther.mRoundedClipRects);
+    mRoundedClipRects = std::move(aOther.mRoundedClipRects);
   }
 
   bool operator==(const MaskLayerUserData& aOther) const {
diff --git a/layout/style/Loader.cpp b/layout/style/Loader.cpp
index 9728a0377d..d4a8bb24cc 100644
--- a/layout/style/Loader.cpp
+++ b/layout/style/Loader.cpp
@@ -128,6 +128,8 @@ static const char* const gStateStrings[] = {"Unknown", "NeedsParser", "Pending",
 namespace mozilla {
 
 class SheetLoadDataHashKey : public nsURIHashKey {
+  using IsPreload = css::Loader::IsPreload;
+
  public:
   typedef SheetLoadDataHashKey* KeyType;
   typedef const SheetLoadDataHashKey* KeyTypePointer;
@@ -137,18 +139,23 @@ class SheetLoadDataHashKey : public nsURIHashKey {
         mPrincipal(aKey->mPrincipal),
         mReferrerInfo(aKey->mReferrerInfo),
         mCORSMode(aKey->mCORSMode),
-        mParsingMode(aKey->mParsingMode) {
+        mParsingMode(aKey->mParsingMode),
+        mSRIMetadata(aKey->mSRIMetadata),
+        mIsLinkPreload(aKey->mIsLinkPreload) {
     MOZ_COUNT_CTOR(SheetLoadDataHashKey);
   }
 
   SheetLoadDataHashKey(nsIURI* aURI, nsIPrincipal* aPrincipal,
                        nsIReferrerInfo* aReferrerInfo, CORSMode aCORSMode,
-                       css::SheetParsingMode aParsingMode)
+                       css::SheetParsingMode aParsingMode,
+                       const SRIMetadata& aSRIMetadata, IsPreload aIsPreload)
       : nsURIHashKey(aURI),
         mPrincipal(aPrincipal),
         mReferrerInfo(aReferrerInfo),
         mCORSMode(aCORSMode),
-        mParsingMode(aParsingMode) {
+        mParsingMode(aParsingMode),
+        mSRIMetadata(aSRIMetadata),
+        mIsLinkPreload(aIsPreload == IsPreload::Yes) {
     MOZ_COUNT_CTOR(SheetLoadDataHashKey);
   }
 
@@ -157,7 +164,9 @@ class SheetLoadDataHashKey : public nsURIHashKey {
         mPrincipal(std::move(toMove.mPrincipal)),
         mReferrerInfo(std::move(toMove.mReferrerInfo)),
         mCORSMode(std::move(toMove.mCORSMode)),
-        mParsingMode(std::move(toMove.mParsingMode)) {
+        mParsingMode(std::move(toMove.mParsingMode)),
+        mSRIMetadata(std::move(toMove.mSRIMetadata)),
+        mIsLinkPreload(std::move(toMove.mIsLinkPreload)) {
     MOZ_COUNT_CTOR(SheetLoadDataHashKey);
   }
 
@@ -194,8 +203,27 @@ class SheetLoadDataHashKey : public nsURIHashKey {
       return false;
     }
 
-    return !mPrincipal ||
-           (NS_SUCCEEDED(mPrincipal->Equals(aKey->mPrincipal, &eq)) && eq);
+    if (mPrincipal && !mPrincipal->Equals(aKey->mPrincipal)) {
+      return false;
+    }
+
+    // Consuming stylesheet tags must never coalesce to <link preload> initiated
+    // speculative loads with a weaker SRI hash or its different value.  This
+    // check makes sure that regular loads will never find such a weaker preload
+    // and rather start a new, independent load with new, stronger SRI checker
+    // set up, so that integrity is ensured.
+    if (mIsLinkPreload != aKey->mIsLinkPreload) {
+      const SRIMetadata& linkPreloadMetadata =
+          mIsLinkPreload ? mSRIMetadata : aKey->mSRIMetadata;
+      const SRIMetadata& consumerPreloadMetadata =
+          mIsLinkPreload ? aKey->mSRIMetadata : mSRIMetadata;
+
+      if (!consumerPreloadMetadata.CanTrustBeDelegatedTo(linkPreloadMetadata)) {
+        return false;
+      }
+    }
+
+    return true;
   }
 
   static const SheetLoadDataHashKey* KeyToPointer(SheetLoadDataHashKey* aKey) {
@@ -218,6 +246,8 @@ class SheetLoadDataHashKey : public nsURIHashKey {
   nsCOMPtr<nsIReferrerInfo> mReferrerInfo;
   CORSMode mCORSMode;
   css::SheetParsingMode mParsingMode;
+  SRIMetadata mSRIMetadata;
+  bool mIsLinkPreload;
 };
 
 SheetLoadDataHashKey::SheetLoadDataHashKey(css::SheetLoadData& aLoadData)
@@ -225,9 +255,12 @@ SheetLoadDataHashKey::SheetLoadDataHashKey(css::SheetLoadData& aLoadData)
       mPrincipal(aLoadData.mLoaderPrincipal),
       mReferrerInfo(aLoadData.ReferrerInfo()),
       mCORSMode(aLoadData.mSheet->GetCORSMode()),
-      mParsingMode(aLoadData.mSheet->ParsingMode()) {
+      mParsingMode(aLoadData.mSheet->ParsingMode()),
+      mIsLinkPreload(aLoadData.IsLinkPreload()) {
   MOZ_COUNT_CTOR(SheetLoadDataHashKey);
+  aLoadData.mSheet->GetIntegrity(mSRIMetadata);
 }
+
 }  // namespace mozilla
 
 namespace mozilla {
@@ -241,7 +274,7 @@ NS_IMPL_ISUPPORTS(SheetLoadData, nsIRunnable, nsIThreadObserver)
 SheetLoadData::SheetLoadData(
     Loader* aLoader, const nsAString& aTitle, nsIURI* aURI, StyleSheet* aSheet,
     bool aSyncLoad, nsIStyleSheetLinkingElement* aOwningElement,
-    IsAlternate aIsAlternate, MediaMatched aMediaMatches,
+    IsAlternate aIsAlternate, MediaMatched aMediaMatches, IsPreload aIsPreload,
     nsICSSLoaderObserver* aObserver, nsIPrincipal* aLoaderPrincipal,
     nsIReferrerInfo* aReferrerInfo, nsINode* aRequestingNode)
     : mLoader(aLoader),
@@ -265,6 +298,7 @@ SheetLoadData::SheetLoadData(
       mIsCrossOriginNoCORS(false),
       mBlockResourceTiming(false),
       mLoadFailed(false),
+      mIsPreload(aIsPreload),
       mOwningElement(aOwningElement),
       mObserver(aObserver),
       mLoaderPrincipal(aLoaderPrincipal),
@@ -288,19 +322,20 @@ SheetLoadData::SheetLoadData(Loader* aLoader, nsIURI* aURI, StyleSheet* aSheet,
       mNext(nullptr),
       mParentData(aParentData),
       mPendingChildren(0),
-      mSyncLoad(false),
-      mIsNonDocumentSheet(false),
+      mSyncLoad(aParentData && aParentData->mSyncLoad),
+      mIsNonDocumentSheet(aParentData && aParentData->mIsNonDocumentSheet),
       mIsLoading(false),
       mIsBeingParsed(false),
       mIsCancelled(false),
       mMustNotify(false),
       mWasAlternate(false),
       mMediaMatched(true),
-      mUseSystemPrincipal(false),
+      mUseSystemPrincipal(aParentData && aParentData->mUseSystemPrincipal),
       mSheetAlreadyComplete(false),
       mIsCrossOriginNoCORS(false),
       mBlockResourceTiming(false),
       mLoadFailed(false),
+      mIsPreload(IsPreload::No),
       mOwningElement(nullptr),
       mObserver(aObserver),
       mLoaderPrincipal(aLoaderPrincipal),
@@ -309,23 +344,19 @@ SheetLoadData::SheetLoadData(Loader* aLoader, nsIURI* aURI, StyleSheet* aSheet,
       mPreloadEncoding(nullptr) {
   MOZ_ASSERT(mLoader, "Must have a loader!");
   if (mParentData) {
-    mSyncLoad = mParentData->mSyncLoad;
-    mIsNonDocumentSheet = mParentData->mIsNonDocumentSheet;
-    mUseSystemPrincipal = mParentData->mUseSystemPrincipal;
-    ++(mParentData->mPendingChildren);
+    ++mParentData->mPendingChildren;
   }
 
   MOZ_ASSERT(!mUseSystemPrincipal || mSyncLoad,
              "Shouldn't use system principal for async loads");
 }
 
-SheetLoadData::SheetLoadData(Loader* aLoader, nsIURI* aURI, StyleSheet* aSheet,
-                             bool aSyncLoad, bool aUseSystemPrincipal,
-                             const Encoding* aPreloadEncoding,
-                             nsICSSLoaderObserver* aObserver,
-                             nsIPrincipal* aLoaderPrincipal,
-                             nsIReferrerInfo* aReferrerInfo,
-                             nsINode* aRequestingNode)
+SheetLoadData::SheetLoadData(
+    Loader* aLoader, nsIURI* aURI, StyleSheet* aSheet, bool aSyncLoad,
+    UseSystemPrincipal aUseSystemPrincipal, IsPreload aIsPreload,
+    const Encoding* aPreloadEncoding, nsICSSLoaderObserver* aObserver,
+    nsIPrincipal* aLoaderPrincipal, nsIReferrerInfo* aReferrerInfo,
+    nsINode* aRequestingNode)
     : mLoader(aLoader),
       mEncoding(nullptr),
       mURI(aURI),
@@ -341,11 +372,12 @@ SheetLoadData::SheetLoadData(Loader* aLoader, nsIURI* aURI, StyleSheet* aSheet,
       mMustNotify(false),
       mWasAlternate(false),
       mMediaMatched(true),
-      mUseSystemPrincipal(aUseSystemPrincipal),
+      mUseSystemPrincipal(aUseSystemPrincipal == UseSystemPrincipal::Yes),
       mSheetAlreadyComplete(false),
       mIsCrossOriginNoCORS(false),
       mBlockResourceTiming(false),
       mLoadFailed(false),
+      mIsPreload(aIsPreload),
       mOwningElement(nullptr),
       mObserver(aObserver),
       mLoaderPrincipal(aLoaderPrincipal),
@@ -358,8 +390,9 @@ SheetLoadData::SheetLoadData(Loader* aLoader, nsIURI* aURI, StyleSheet* aSheet,
 }
 
 SheetLoadData::~SheetLoadData() {
-  MOZ_DIAGNOSTIC_ASSERT(mSheetCompleteCalled,
-                        "Should always call SheetComplete");
+  MOZ_DIAGNOSTIC_ASSERT(mSheetCompleteCalled || mIntentionallyDropped,
+                        "Should always call SheetComplete, except when "
+                        "dropping the load");
 
   // Do this iteratively to avoid blowing up the stack.
   RefPtr<SheetLoadData> next = std::move(mNext);
@@ -469,7 +502,7 @@ struct Loader::Sheets {
   RefPtr<StyleSheet> LookupInline(const nsAString&);
 
   // A cache hit or miss. It is a miss if the `StyleSheet` is null.
-  using CacheResult = Tuple<RefPtr<StyleSheet>, SheetState>;
+  using CacheResult = std::tuple<RefPtr<StyleSheet>, SheetState>;
   CacheResult Lookup(SheetLoadDataHashKey&, bool aSyncLoad);
 
   size_t SizeOfIncludingThis(MallocSizeOf) const;
@@ -526,7 +559,7 @@ auto Loader::Sheets::Lookup(SheetLoadDataHashKey& aKey, bool aSyncLoad)
         // keys off the URI. See below for the unique inner check.
         if (!sheet->HasForcedUniqueInner() &&
             sheet->ParsingMode() == aKey.ParsingMode()) {
-          return MakeTuple(CloneSheet(*sheet), SheetState::Complete);
+          return {CloneSheet(*sheet), SheetState::Complete};
         }
         LOG(
             ("    Not cloning due to forced unique inner or mismatched "
@@ -552,7 +585,7 @@ auto Loader::Sheets::Lookup(SheetLoadDataHashKey& aKey, bool aSyncLoad)
         // up with two copies of our inner hanging around.
         lookup.Data() = clone;
       }
-      return MakeTuple(std::move(clone), SheetState::Complete);
+      return {std::move(clone), SheetState::Complete};
     }
     LOG(("    Not cloning due to forced unique inner"));
     // Remove it now that we know that we're never going to use this stylesheet
@@ -567,13 +600,13 @@ auto Loader::Sheets::Lookup(SheetLoadDataHashKey& aKey, bool aSyncLoad)
   if (SheetLoadData* data = mLoadingDatas.Get(&aKey)) {
     LOG(("  From loading: %p", data->mSheet.get()));
     AssertIncompleteSheetMatches(*data, aKey);
-    return MakeTuple(CloneSheet(*data->mSheet), SheetState::Loading);
+    return {CloneSheet(*data->mSheet), SheetState::Loading};
   }
 
   if (SheetLoadData* data = mPendingDatas.GetWeak(&aKey)) {
     LOG(("  From pending: %p", data->mSheet.get()));
     AssertIncompleteSheetMatches(*data, aKey);
-    return MakeTuple(CloneSheet(*data->mSheet), SheetState::Pending);
+    return {CloneSheet(*data->mSheet), SheetState::Pending};
   }
 
   return {};
@@ -677,7 +710,7 @@ void Loader::DocumentStyleSheetSetChanged() {
   mDatasToNotifyOn += arr.Length();
   for (RefPtr<SheetLoadData>& data : arr) {
     --mDatasToNotifyOn;
-    LoadSheet(*data, SheetState::NeedsParser, IsPreload::No);
+    LoadSheet(*data, SheetState::NeedsParser);
   }
 }
 
@@ -1090,11 +1123,11 @@ nsresult Loader::CheckContentPolicy(nsIPrincipal* aLoadingPrincipal,
  * state of the sheet they are clones off; make sure to call PrepareSheet() on
  * the result of CreateSheet().
  */
-Tuple<RefPtr<StyleSheet>, Loader::SheetState> Loader::CreateSheet(
+std::tuple<RefPtr<StyleSheet>, Loader::SheetState> Loader::CreateSheet(
     nsIURI* aURI, nsIContent* aLinkingContent, nsIPrincipal* aLoaderPrincipal,
     css::SheetParsingMode aParsingMode, CORSMode aCORSMode,
     nsIReferrerInfo* aLoadingReferrerInfo, const nsAString& aIntegrity,
-    bool aSyncLoad) {
+    bool aSyncLoad, IsPreload aIsPreload) {
   MOZ_ASSERT(aURI, "This path is not taken for inline stylesheets");
   LOG(("css::Loader::CreateSheet(%s)", aURI->GetSpecOrDefault().get()));
 
@@ -1102,19 +1135,6 @@ Tuple<RefPtr<StyleSheet>, Loader::SheetState> Loader::CreateSheet(
     mSheets = MakeUnique<Sheets>();
   }
 
-  SheetLoadDataHashKey key(aURI, aLoaderPrincipal, aLoadingReferrerInfo,
-                           aCORSMode, aParsingMode);
-  auto cacheResult = mSheets->Lookup(key, aSyncLoad);
-  if (Get<0>(cacheResult)) {
-    LOG(("  Hit cache with state: %s",
-         gStateStrings[size_t(Get<1>(cacheResult))]));
-    return cacheResult;
-  }
-
-  nsIURI* sheetURI = aURI;
-  nsIURI* baseURI = aURI;
-  nsIURI* originalURI = aURI;
-
   SRIMetadata sriMetadata;
   if (!aIntegrity.IsEmpty()) {
     MOZ_LOG(gSriPRLog, LogLevel::Debug,
@@ -1127,13 +1147,25 @@ Tuple<RefPtr<StyleSheet>, Loader::SheetState> Loader::CreateSheet(
     SRICheck::IntegrityMetadata(aIntegrity, sourceUri, mReporter, &sriMetadata);
   }
 
+  SheetLoadDataHashKey key(aURI, aLoaderPrincipal, aLoadingReferrerInfo,
+                           aCORSMode, aParsingMode, sriMetadata, aIsPreload);
+  auto cacheResult = mSheets->Lookup(key, aSyncLoad);
+  if (const auto& [styleSheet, sheetState] = cacheResult; styleSheet) {
+    LOG(("  Hit cache with state: %s", gStateStrings[size_t(sheetState)]));
+    return cacheResult;
+  }
+
+  nsIURI* sheetURI = aURI;
+  nsIURI* baseURI = aURI;
+  nsIURI* originalURI = aURI;
+
   auto sheet = MakeRefPtr<StyleSheet>(aParsingMode, aCORSMode, sriMetadata);
   sheet->SetURIs(sheetURI, originalURI, baseURI);
   nsCOMPtr<nsIReferrerInfo> referrerInfo =
       ReferrerInfo::CreateForExternalCSSResources(sheet);
   sheet->SetReferrerInfo(referrerInfo);
   LOG(("  Needs parser"));
-  return MakeTuple(std::move(sheet), SheetState::NeedsParser);
+  return {std::move(sheet), SheetState::NeedsParser};
 }
 
 static Loader::MediaMatched MediaListMatches(const MediaList* aMediaList,
@@ -1291,8 +1323,7 @@ void Loader::InsertChildSheet(StyleSheet& aSheet, StyleSheet& aParentSheet) {
  * existing load for this URI and piggyback on it.  Failing all that,
  * a new load is kicked off asynchronously.
  */
-nsresult Loader::LoadSheet(SheetLoadData& aLoadData, SheetState aSheetState,
-                           IsPreload aIsPreload) {
+nsresult Loader::LoadSheet(SheetLoadData& aLoadData, SheetState aSheetState) {
   LOG(("css::Loader::LoadSheet"));
   MOZ_ASSERT(aLoadData.mURI, "Need a URI to load");
   MOZ_ASSERT(aLoadData.mSheet, "Need a sheet to load into");
@@ -1337,7 +1368,7 @@ nsresult Loader::LoadSheet(SheetLoadData& aLoadData, SheetState aSheetState,
         nsILoadInfo::SEC_ALLOW_CHROME;
 
     nsContentPolicyType contentPolicyType =
-        aIsPreload == IsPreload::Yes
+        aLoadData.mIsPreload == IsPreload::Yes
             ? nsIContentPolicy::TYPE_INTERNAL_STYLESHEET_PRELOAD
             : nsIContentPolicy::TYPE_INTERNAL_STYLESHEET;
 
@@ -1442,7 +1473,7 @@ nsresult Loader::LoadSheet(SheetLoadData& aLoadData, SheetState aSheetState,
       MOZ_ASSERT(removedData == existingData, "Bad loading table");
 
       LOG(("  Forcing load of pending data"));
-      return LoadSheet(*removedData, SheetState::NeedsParser, aIsPreload);
+      return LoadSheet(*removedData, SheetState::NeedsParser);
     }
     // All done here; once the load completes we'll be marked complete
     // automatically
@@ -1482,7 +1513,7 @@ nsresult Loader::LoadSheet(SheetLoadData& aLoadData, SheetState aSheetState,
   securityFlags |= nsILoadInfo::SEC_ALLOW_CHROME;
 
   nsContentPolicyType contentPolicyType =
-      aIsPreload == IsPreload::Yes
+      aLoadData.mIsPreload == IsPreload::Yes
           ? nsIContentPolicy::TYPE_INTERNAL_STYLESHEET_PRELOAD
           : nsIContentPolicy::TYPE_INTERNAL_STYLESHEET;
 
@@ -1831,8 +1862,16 @@ void Loader::DoSheetComplete(SheetLoadData& aLoadData,
     } else {
 #endif
       SheetLoadDataHashKey key(aLoadData);
-      NS_ASSERTION(sheet->IsComplete(),
-                   "Should only be caching complete sheets");
+      MOZ_ASSERT(sheet->IsComplete(), "Should only be caching complete sheets");
+
+#ifdef MOZ_DIAGNOSTIC_ASSERT_ENABLED
+      for (const auto& entry : mSheets->mCompleteSheets) {
+        MOZ_DIAGNOSTIC_ASSERT(
+            entry.GetData() != sheet || key.KeyEquals(entry.GetKey()),
+            "Same sheet, different keys?");
+      }
+#endif
+
       mSheets->mCompleteSheets.Put(&key, RefPtr{sheet});
 #ifdef MOZ_XUL
     }
@@ -1936,7 +1975,8 @@ Result<Loader::LoadSheetResult, nsresult> Loader::LoadInlineStyle(
   } else {
     auto data = MakeRefPtr<SheetLoadData>(
         this, aInfo.mTitle, nullptr, sheet, false, owningElement, isAlternate,
-        matched, aObserver, nullptr, aInfo.mReferrerInfo, aInfo.mContent);
+        matched, IsPreload::No, aObserver, nullptr, aInfo.mReferrerInfo,
+        aInfo.mContent);
     data->mLineNumber = aLineNumber;
     // Parse completion releases the load data.
     //
@@ -2016,11 +2056,8 @@ Result<Loader::LoadSheetResult, nsresult> Loader::LoadStyleLink(
   // Check IsAlternateSheet now, since it can mutate our document and make
   // pending sheets go to the non-pending state.
   auto isAlternate = IsAlternateSheet(aInfo.mTitle, aInfo.mHasAlternateRel);
-
-  SheetState state;
-  RefPtr<StyleSheet> sheet;
-  Tie(sheet, state) =
-      CreateSheet(aInfo, principal, eAuthorSheetFeatures, syncLoad);
+  auto [sheet, state] = CreateSheet(aInfo, principal, eAuthorSheetFeatures,
+                                    syncLoad, IsPreload::No);
 
   LOG(("  Sheet is alternate: %d", static_cast<int>(isAlternate)));
 
@@ -2031,15 +2068,28 @@ Result<Loader::LoadSheetResult, nsresult> Loader::LoadStyleLink(
 
   nsCOMPtr<nsIStyleSheetLinkingElement> owningElement(
       do_QueryInterface(aInfo.mContent));
+  // We may get here with no content for Link: headers for example.
+  MOZ_ASSERT(!!owningElement == !!aInfo.mContent,
+             "If there is any node, it should be an "
+             "nsIStyleSheetLinkingElement");
 
+  auto data = MakeRefPtr<SheetLoadData>(
+      this, aInfo.mTitle, aInfo.mURI, sheet, syncLoad, owningElement,
+      isAlternate, matched, IsPreload::No, aObserver, principal,
+      aInfo.mReferrerInfo, context);
   if (state == SheetState::Complete) {
     LOG(("  Sheet already complete: 0x%p", sheet.get()));
     if (aObserver || !mObservers.IsEmpty() || owningElement) {
-      rv = PostLoadEvent(aInfo.mURI, sheet, aObserver, isAlternate, matched,
-                         aInfo.mReferrerInfo, owningElement);
+      rv = PostLoadEvent(std::move(data));
       if (NS_FAILED(rv)) {
         return Err(rv);
       }
+    } else {
+#ifdef MOZ_DIAGNOSTIC_ASSERT_ENABLED
+      // We don't have to notify anyone of this load, as it was complete, so
+      // drop it intentionally.
+      data->mIntentionallyDropped = true;
+#endif
     }
 
     // The load hasn't been completed yet, will be done in PostLoadEvent.
@@ -2047,9 +2097,6 @@ Result<Loader::LoadSheetResult, nsresult> Loader::LoadStyleLink(
   }
 
   // Now we need to actually load it.
-  auto data = MakeRefPtr<SheetLoadData>(
-      this, aInfo.mTitle, aInfo.mURI, sheet, syncLoad, owningElement,
-      isAlternate, matched, aObserver, principal, aInfo.mReferrerInfo, context);
 
   auto result = LoadSheetResult{Completed::No, isAlternate, matched};
 
@@ -2067,7 +2114,7 @@ Result<Loader::LoadSheetResult, nsresult> Loader::LoadStyleLink(
   }
 
   // Load completion will free the data
-  rv = LoadSheet(*data, state, IsPreload::No);
+  rv = LoadSheet(*data, state);
   if (NS_FAILED(rv)) {
     return Err(rv);
   }
@@ -2181,11 +2228,11 @@ nsresult Loader::LoadChildSheet(StyleSheet& aParentSheet,
     state = SheetState::Complete;
   } else {
     // For now, use CORS_NONE for child sheets
-    Tie(sheet, state) =
+    std::tie(sheet, state) =
         CreateSheet(aURL, nullptr, principal, aParentSheet.ParsingMode(),
                     CORS_NONE, aParentSheet.GetReferrerInfo(),
                     EmptyString(),  // integrity is only checked on main sheet
-                    aParentData ? aParentData->mSyncLoad : false);
+                    aParentData && aParentData->mSyncLoad, IsPreload::No);
     PrepareSheet(*sheet, EmptyString(), EmptyString(), aMedia, IsAlternate::No,
                  IsExplicitlyEnabled::No);
   }
@@ -2208,7 +2255,7 @@ nsresult Loader::LoadChildSheet(StyleSheet& aParentSheet,
   bool syncLoad = data->mSyncLoad;
 
   // Load completion will release the data
-  rv = LoadSheet(*data, state, IsPreload::No);
+  rv = LoadSheet(*data, state);
   NS_ENSURE_SUCCESS(rv, rv);
 
   if (!syncLoad) {
@@ -2275,33 +2322,34 @@ Result<RefPtr<StyleSheet>, nsresult> Loader::InternalLoadNonDocumentSheet(
   }
 
   bool syncLoad = !aObserver;
-
-  SheetState state;
-  RefPtr<StyleSheet> sheet;
-  Tie(sheet, state) =
+  auto [sheet, state] =
       CreateSheet(aURL, nullptr, aOriginPrincipal, aParsingMode, aCORSMode,
-                  aReferrerInfo, aIntegrity, syncLoad);
+                  aReferrerInfo, aIntegrity, syncLoad, aIsPreload);
 
   PrepareSheet(*sheet, EmptyString(), EmptyString(), nullptr, IsAlternate::No,
                IsExplicitlyEnabled::No);
 
+  auto data = MakeRefPtr<SheetLoadData>(
+      this, aURL, sheet, syncLoad, aUseSystemPrincipal, aIsPreload,
+      aPreloadEncoding, aObserver, aOriginPrincipal, aReferrerInfo, mDocument);
   if (state == SheetState::Complete) {
     LOG(("  Sheet already complete"));
     if (aObserver || !mObservers.IsEmpty()) {
-      rv = PostLoadEvent(aURL, sheet, aObserver, IsAlternate::No,
-                         MediaMatched::Yes, aReferrerInfo, nullptr);
+      rv = PostLoadEvent(std::move(data));
       if (NS_FAILED(rv)) {
         return Err(rv);
       }
+    } else {
+      // We don't have to notify anyone of this load, as it was complete, so
+      // drop it intentionally.
+#ifdef MOZ_DIAGNOSTIC_ASSERT_ENABLED
+      data->mIntentionallyDropped = true;
+#endif
     }
     return sheet;
   }
 
-  auto data = MakeRefPtr<SheetLoadData>(
-      this, aURL, sheet, syncLoad,
-      aUseSystemPrincipal == UseSystemPrincipal::Yes, aPreloadEncoding,
-      aObserver, aOriginPrincipal, aReferrerInfo, mDocument);
-  rv = LoadSheet(*data, state, aIsPreload);
+  rv = LoadSheet(*data, state);
   if (NS_FAILED(rv)) {
     return Err(rv);
   }
@@ -2311,27 +2359,12 @@ Result<RefPtr<StyleSheet>, nsresult> Loader::InternalLoadNonDocumentSheet(
   return sheet;
 }
 
-nsresult Loader::PostLoadEvent(nsIURI* aURI, StyleSheet* aSheet,
-                               nsICSSLoaderObserver* aObserver,
-                               IsAlternate aWasAlternate,
-                               MediaMatched aMediaMatched,
-                               nsIReferrerInfo* aReferrerInfo,
-                               nsIStyleSheetLinkingElement* aElement) {
+nsresult Loader::PostLoadEvent(RefPtr<SheetLoadData> aLoadData) {
   LOG(("css::Loader::PostLoadEvent"));
-  MOZ_ASSERT(aSheet, "Must have sheet");
-  MOZ_ASSERT(aObserver || !mObservers.IsEmpty() || aElement,
-             "Must have observer or element");
-
-  RefPtr<SheetLoadData> evt = new SheetLoadData(
-      this,
-      EmptyString(),  // title doesn't matter here
-      aURI, aSheet, false, aElement, aWasAlternate, aMediaMatched, aObserver,
-      nullptr, aReferrerInfo, mDocument);
-
-  mPostedEvents.AppendElement(evt);
+  mPostedEvents.AppendElement(aLoadData);
 
   nsresult rv;
-  RefPtr<SheetLoadData> runnable(evt);
+  RefPtr<SheetLoadData> runnable(aLoadData);
   if (mDocument) {
     rv = mDocument->Dispatch(TaskCategory::Other, runnable.forget());
   } else if (mDocGroup) {
@@ -2342,22 +2375,22 @@ nsresult Loader::PostLoadEvent(nsIURI* aURI, StyleSheet* aSheet,
 
   if (NS_FAILED(rv)) {
     NS_WARNING("failed to dispatch stylesheet load event");
-    mPostedEvents.RemoveElement(evt);
+    mPostedEvents.RemoveElement(aLoadData);
   } else {
     // We'll unblock onload when we handle the event.
     BlockOnload();
 
     // We want to notify the observer for this data.
-    evt->mMustNotify = true;
-    evt->mSheetAlreadyComplete = true;
+    aLoadData->mMustNotify = true;
+    aLoadData->mSheetAlreadyComplete = true;
 
     // If we get to this code, aSheet loaded correctly at some point, so
     // we can just schedule a load event and don't need to touch the
     // data's mLoadFailed.  Note that we do this here and not from
     // inside our SheetComplete so that we don't end up running the load
     // event async.
-    MOZ_ASSERT(!evt->mLoadFailed, "Why are we marked as failed?");
-    evt->ScheduleLoadEventIfNeeded();
+    MOZ_ASSERT(!aLoadData->mLoadFailed, "Why are we marked as failed?");
+    aLoadData->ScheduleLoadEventIfNeeded();
   }
 
   return rv;
@@ -2445,7 +2478,7 @@ void Loader::StartDeferredLoads() {
   mDatasToNotifyOn += arr.Length();
   for (RefPtr<SheetLoadData>& data : arr) {
     --mDatasToNotifyOn;
-    LoadSheet(*data, SheetState::NeedsParser, IsPreload::No);
+    LoadSheet(*data, SheetState::NeedsParser);
   }
 }
 
diff --git a/layout/style/Loader.h b/layout/style/Loader.h
index 7da343682a..3258b550c9 100644
--- a/layout/style/Loader.h
+++ b/layout/style/Loader.h
@@ -7,24 +7,26 @@
 #ifndef mozilla_css_Loader_h
 #define mozilla_css_Loader_h
 
-#include "nsIPrincipal.h"
+#include <tuple>
+#include <utility>
+
+#include "mozilla/Attributes.h"
+#include "mozilla/CORSMode.h"
+#include "mozilla/Maybe.h"
+#include "mozilla/MemoryReporting.h"
+#include "mozilla/StyleSheet.h"
+#include "mozilla/StyleSheetInlines.h"
+#include "mozilla/UniquePtr.h"
 #include "nsCompatibility.h"
 #include "nsCycleCollectionParticipant.h"
 #include "nsDataHashtable.h"
+#include "nsIPrincipal.h"
+#include "nsIStyleSheetLinkingElement.h"
 #include "nsRefPtrHashtable.h"
 #include "nsStringFwd.h"
 #include "nsTArray.h"
 #include "nsTObserverArray.h"
 #include "nsURIHashKey.h"
-#include "nsIStyleSheetLinkingElement.h"
-#include "mozilla/Attributes.h"
-#include "mozilla/CORSMode.h"
-#include "mozilla/StyleSheetInlines.h"
-#include "mozilla/Maybe.h"
-#include "mozilla/MemoryReporting.h"
-#include "mozilla/Move.h"
-#include "mozilla/StyleSheet.h"
-#include "mozilla/UniquePtr.h"
 
 class nsICSSLoaderObserver;
 class nsIConsoleReportCollector;
@@ -203,7 +205,7 @@ class Loader final {
       nsIURI*, SheetParsingMode = eAuthorSheetFeatures,
       UseSystemPrincipal = UseSystemPrincipal::No);
 
-  enum class IsPreload { No, Yes };
+  enum class IsPreload : uint8_t { No, Yes };
 
   /**
    * Asynchronously load the stylesheet at aURL.  If a successful result is
@@ -331,21 +333,22 @@ class Loader final {
     Complete
   };
 
-  Tuple<RefPtr<StyleSheet>, SheetState> CreateSheet(
+  std::tuple<RefPtr<StyleSheet>, SheetState> CreateSheet(
       const SheetInfo& aInfo, nsIPrincipal* aLoaderPrincipal,
-      css::SheetParsingMode aParsingMode, bool aSyncLoad) {
+      css::SheetParsingMode aParsingMode, bool aSyncLoad,
+      IsPreload aIsPreload) {
     return CreateSheet(aInfo.mURI, aInfo.mContent, aLoaderPrincipal,
                        aParsingMode, aInfo.mCORSMode, aInfo.mReferrerInfo,
-                       aInfo.mIntegrity, aSyncLoad);
+                       aInfo.mIntegrity, aSyncLoad, aIsPreload);
   }
 
   // For inline style, the aURI param is null, but the aLinkingContent
   // must be non-null then.  The loader principal must never be null
   // if aURI is not null.
-  Tuple<RefPtr<StyleSheet>, SheetState> CreateSheet(
+  std::tuple<RefPtr<StyleSheet>, SheetState> CreateSheet(
       nsIURI* aURI, nsIContent* aLinkingContent, nsIPrincipal* aLoaderPrincipal,
       css::SheetParsingMode, CORSMode, nsIReferrerInfo* aLoadingReferrerInfo,
-      const nsAString& aIntegrity, bool aSyncLoad);
+      const nsAString& aIntegrity, bool aSyncLoad, IsPreload aIsPreload);
 
   // Pass in either a media string or the MediaList from the CSSParser.  Don't
   // pass both.
@@ -370,15 +373,8 @@ class Loader final {
   // Post a load event for aObserver to be notified about aSheet.  The
   // notification will be sent with status NS_OK unless the load event is
   // canceled at some point (in which case it will be sent with
-  // NS_BINDING_ABORTED).  aWasAlternate indicates the state when the load was
-  // initiated, not the state at some later time.  aURI should be the URI the
-  // sheet was loaded from (may be null for inline sheets).  aElement is the
-  // owning element for this sheet.
-  nsresult PostLoadEvent(nsIURI* aURI, StyleSheet* aSheet,
-                         nsICSSLoaderObserver* aObserver,
-                         IsAlternate aWasAlternate, MediaMatched aMediaMatched,
-                         nsIReferrerInfo* aReferrerInfo,
-                         nsIStyleSheetLinkingElement* aElement);
+  // NS_BINDING_ABORTED).
+  nsresult PostLoadEvent(RefPtr<SheetLoadData>);
 
   // Start the loads of all the sheets in mPendingDatas
   void StartDeferredLoads();
@@ -387,7 +383,7 @@ class Loader final {
 
   // Note: LoadSheet is responsible for setting the sheet to complete on
   // failure.
-  nsresult LoadSheet(SheetLoadData&, SheetState, IsPreload);
+  nsresult LoadSheet(SheetLoadData&, SheetState);
 
   enum class AllowAsyncParse {
     Yes,
diff --git a/layout/style/PaintWorkletGlobalScope.cpp b/layout/style/PaintWorkletGlobalScope.cpp
index 6ec6068b29..572e35f293 100644
--- a/layout/style/PaintWorkletGlobalScope.cpp
+++ b/layout/style/PaintWorkletGlobalScope.cpp
@@ -18,6 +18,17 @@ PaintWorkletGlobalScope::PaintWorkletGlobalScope(PaintWorkletImpl* aImpl)
 bool PaintWorkletGlobalScope::WrapGlobalObject(
     JSContext* aCx, JS::MutableHandle<JSObject*> aReflector) {
   JS::RealmOptions options;
+
+  // The SharedArrayBuffer global constructor property should not be present in
+  // a fresh global object when shared memory objects aren't allowed (because
+  // COOP/COEP support isn't enabled, or because COOP/COEP don't act to isolate
+  // this worker to a separate process).  However, it's not presently clear how
+  // to do this, so for now assign a backwards-compatible value.  Bug 1630876
+  // will fix this.
+  bool defineSharedArrayBufferConstructor = true;
+  options.creationOptions().setDefineSharedArrayBufferConstructor(
+      defineSharedArrayBufferConstructor);
+
   JS::AutoHoldPrincipals principals(aCx, new WorkletPrincipals(mImpl));
   return PaintWorkletGlobalScope_Binding::Wrap(
       aCx, this, this, options, principals.get(), true, aReflector);
diff --git a/layout/style/PaintWorkletImpl.cpp b/layout/style/PaintWorkletImpl.cpp
index e48748c900..e085ca027a 100644
--- a/layout/style/PaintWorkletImpl.cpp
+++ b/layout/style/PaintWorkletImpl.cpp
@@ -20,7 +20,11 @@ namespace mozilla {
 
 PaintWorkletImpl::PaintWorkletImpl(nsPIDOMWindowInner* aWindow,
                                    nsIPrincipal* aPrincipal)
-    : WorkletImpl(aWindow, aPrincipal) {}
+    : WorkletImpl(aWindow, aPrincipal) {
+#ifdef RELEASE_OR_BETA
+  MOZ_CRASH("This code should not go to release/beta yet!");
+#endif
+}
 
 PaintWorkletImpl::~PaintWorkletImpl() = default;
 
diff --git a/layout/style/ServoStyleSet.cpp b/layout/style/ServoStyleSet.cpp
index 69ed3c5145..58d13fb315 100644
--- a/layout/style/ServoStyleSet.cpp
+++ b/layout/style/ServoStyleSet.cpp
@@ -976,10 +976,7 @@ bool ServoStyleSet::EnsureUniqueInnerOnCSSSheets() {
   });
 
   while (!queue.IsEmpty()) {
-    uint32_t idx = queue.Length() - 1;
-    auto* sheet = queue[idx].first;
-    SheetOwner owner = queue[idx].second;
-    queue.RemoveElementAt(idx);
+    auto [sheet, owner] = queue.PopLastElement();
 
     // Only call EnsureUniqueInner for complete sheets. If we do call it on
     // incomplete sheets, we'll cause problems when the sheet is actually
@@ -1185,8 +1182,7 @@ void ServoStyleSet::RunPostTraversalTasks() {
     return;
   }
 
-  nsTArray<PostTraversalTask> tasks;
-  tasks.SwapElements(mPostTraversalTasks);
+  nsTArray<PostTraversalTask> tasks = std::move(mPostTraversalTasks);
 
   for (auto& task : tasks) {
     task.Run();
diff --git a/layout/style/SheetLoadData.h b/layout/style/SheetLoadData.h
index 49849474c3..ee9e0da85d 100644
--- a/layout/style/SheetLoadData.h
+++ b/layout/style/SheetLoadData.h
@@ -34,8 +34,10 @@ static_assert(eAuthorSheetFeatures == 0 && eUserSheetFeatures == 1 &&
               "in SheetLoadData::mParsingMode");
 
 class SheetLoadData final : public nsIRunnable, public nsIThreadObserver {
-  typedef nsIStyleSheetLinkingElement::MediaMatched MediaMatched;
-  typedef nsIStyleSheetLinkingElement::IsAlternate IsAlternate;
+  using MediaMatched = nsIStyleSheetLinkingElement::MediaMatched;
+  using IsAlternate = nsIStyleSheetLinkingElement::IsAlternate;
+  using IsPreload = Loader::IsPreload;
+  using UseSystemPrincipal = Loader::UseSystemPrincipal;
 
  protected:
   virtual ~SheetLoadData();
@@ -46,8 +48,9 @@ class SheetLoadData final : public nsIRunnable, public nsIThreadObserver {
                 StyleSheet* aSheet, bool aSyncLoad,
                 nsIStyleSheetLinkingElement* aOwningElement,
                 IsAlternate aIsAlternate, MediaMatched aMediaMatched,
-                nsICSSLoaderObserver* aObserver, nsIPrincipal* aLoaderPrincipal,
-                nsIReferrerInfo* aReferrerInfo, nsINode* aRequestingNode);
+                IsPreload aIsPreload, nsICSSLoaderObserver* aObserver,
+                nsIPrincipal* aLoaderPrincipal, nsIReferrerInfo* aReferrerInfo,
+                nsINode* aRequestingNode);
 
   // Data for loading a sheet linked from an @import rule
   SheetLoadData(Loader* aLoader, nsIURI* aURI, StyleSheet* aSheet,
@@ -57,7 +60,7 @@ class SheetLoadData final : public nsIRunnable, public nsIThreadObserver {
 
   // Data for loading a non-document sheet
   SheetLoadData(Loader* aLoader, nsIURI* aURI, StyleSheet* aSheet,
-                bool aSyncLoad, bool aUseSystemPrincipal,
+                bool aSyncLoad, UseSystemPrincipal, IsPreload,
                 const Encoding* aPreloadEncoding,
                 nsICSSLoaderObserver* aObserver, nsIPrincipal* aLoaderPrincipal,
                 nsIReferrerInfo* aReferrerInfo, nsINode* aRequestingNode);
@@ -81,11 +84,11 @@ class SheetLoadData final : public nsIRunnable, public nsIThreadObserver {
 
   // Hold a ref to the CSSLoader so we can call back to it to let it
   // know the load finished
-  RefPtr<Loader> mLoader;
+  const RefPtr<Loader> mLoader;
 
   // Title needed to pull datas out of the pending datas table when
   // the preferred title is changed
-  nsString mTitle;
+  const nsString mTitle;
 
   // The encoding we decided to use for the sheet
   const Encoding* mEncoding;
@@ -97,14 +100,14 @@ class SheetLoadData final : public nsIRunnable, public nsIThreadObserver {
   uint32_t mLineNumber;
 
   // The sheet we're loading data for
-  RefPtr<StyleSheet> mSheet;
+  const RefPtr<StyleSheet> mSheet;
 
   // Linked list of datas for the same URI as us.
   RefPtr<SheetLoadData> mNext;
 
   // Load data for the sheet that @import-ed us if we were @import-ed
   // during the parse
-  RefPtr<SheetLoadData> mParentData;
+  const RefPtr<SheetLoadData> mParentData;
 
   // Number of sheets we @import-ed that are still loading
   uint32_t mPendingChildren;
@@ -112,12 +115,12 @@ class SheetLoadData final : public nsIRunnable, public nsIThreadObserver {
   // mSyncLoad is true when the load needs to be synchronous.
   // For LoadSheetSync, <link> to chrome stylesheets in UA Widgets,
   // and children of sync loads.
-  bool mSyncLoad : 1;
+  const bool mSyncLoad : 1;
 
   // mIsNonDocumentSheet is true if the load was triggered by LoadSheetSync or
   // LoadSheet or an @import from such a sheet.  Non-document sheet loads can
   // proceed even if we have no document.
-  bool mIsNonDocumentSheet : 1;
+  const bool mIsNonDocumentSheet : 1;
 
   // mIsLoading is true from the moment we are placed in the loader's
   // "loading datas" table (right after the async channel is opened)
@@ -143,16 +146,16 @@ class SheetLoadData final : public nsIRunnable, public nsIThreadObserver {
 
   // mWasAlternate is true if the sheet was an alternate when the load data was
   // created.
-  bool mWasAlternate : 1;
+  const bool mWasAlternate : 1;
 
   // mMediaMatched is true if the sheet matched its medialist when the load data
   // was created.
-  bool mMediaMatched : 1;
+  const bool mMediaMatched : 1;
 
   // mUseSystemPrincipal is true if the system principal should be used for
   // this sheet, no matter what the channel principal is.  Only true for sync
   // loads.
-  bool mUseSystemPrincipal : 1;
+  const bool mUseSystemPrincipal : 1;
 
   // If true, this SheetLoadData is being used as a way to handle
   // async observer notification for an already-complete sheet.
@@ -174,29 +177,39 @@ class SheetLoadData final : public nsIRunnable, public nsIThreadObserver {
   // to true if this load, or the load of any descendant import, fails.
   bool mLoadFailed : 1;
 
+  // Whether this is a preload, and which kind of preload it is.
+  //
+  // TODO(emilio): This can become a bitfield once we build with a GCC version
+  // that has the fix for https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61414,
+  // which causes a false positive warning here.
+  const IsPreload mIsPreload;
+
   // This is the element that imported the sheet.  Needed to get the
   // charset set on it and to fire load/error events.
-  nsCOMPtr<nsIStyleSheetLinkingElement> mOwningElement;
+  const nsCOMPtr<nsIStyleSheetLinkingElement> mOwningElement;
 
   // The observer that wishes to be notified of load completion
-  nsCOMPtr<nsICSSLoaderObserver> mObserver;
+  const nsCOMPtr<nsICSSLoaderObserver> mObserver;
 
   // The principal that identifies who started loading us.
-  nsCOMPtr<nsIPrincipal> mLoaderPrincipal;
+  const nsCOMPtr<nsIPrincipal> mLoaderPrincipal;
 
   // Referrer info of the load.
-  nsCOMPtr<nsIReferrerInfo> mReferrerInfo;
+  const nsCOMPtr<nsIReferrerInfo> mReferrerInfo;
 
   // The node that identifies who started loading us.
-  nsCOMPtr<nsINode> mRequestingNode;
+  const nsCOMPtr<nsINode> mRequestingNode;
 
   // The encoding to use for preloading Must be empty if mOwningElement
   // is non-null.
-  const Encoding* mPreloadEncoding;
+  const Encoding* const mPreloadEncoding;
 
 #ifdef MOZ_DIAGNOSTIC_ASSERT_ENABLED
   // Whether SheetComplete was called.
   bool mSheetCompleteCalled = false;
+  // Whether we intentionally are not calling SheetComplete because nobody is
+  // listening for the load.
+  bool mIntentionallyDropped = false;
 #endif
 
   bool ShouldDefer() const { return mWasAlternate || !mMediaMatched; }
@@ -212,11 +225,13 @@ class SheetLoadData final : public nsIRunnable, public nsIThreadObserver {
     }
   }
 
+  bool IsLinkPreload() const { return mIsPreload == IsPreload::Yes; }
+
  private:
   void FireLoadEvent(nsIThreadInternal* aThread);
 };
 
-typedef nsMainThreadPtrHolder<SheetLoadData> SheetLoadDataHolder;
+using SheetLoadDataHolder = nsMainThreadPtrHolder<SheetLoadData>;
 
 }  // namespace css
 }  // namespace mozilla
diff --git a/layout/style/StyleSheet.cpp b/layout/style/StyleSheet.cpp
index fda7a3f8d9..0686ced4a7 100644
--- a/layout/style/StyleSheet.cpp
+++ b/layout/style/StyleSheet.cpp
@@ -696,7 +696,8 @@ already_AddRefed<dom::Promise> StyleSheet::Replace(const nsACString& aText,
   auto* loader = mConstructorDocument->CSSLoader();
   auto loadData = MakeRefPtr<css::SheetLoadData>(
       loader, GetBaseURI(), this, /* aSyncLoad */ false,
-      /* aUseSystemPrincipal */ false, /* aPreloadEncoding */ nullptr,
+      css::Loader::UseSystemPrincipal::No, css::Loader::IsPreload::No,
+      /* aPreloadEncoding */ nullptr,
       /* aObserver */ nullptr, /* aLoaderPrincipal */ nullptr,
       GetReferrerInfo(),
       /* aRequestingNode */ nullptr);
diff --git a/layout/style/nsStyleStruct.cpp b/layout/style/nsStyleStruct.cpp
index ff1f1b5631..01b58faaf0 100644
--- a/layout/style/nsStyleStruct.cpp
+++ b/layout/style/nsStyleStruct.cpp
@@ -1845,6 +1845,11 @@ nsStyleImageLayers& nsStyleImageLayers::operator=(nsStyleImageLayers&& aOther) {
   mCompositeCount = aOther.mCompositeCount;
   mLayers = std::move(aOther.mLayers);
 
+  // XXX(Bug 1657087) The OOM check doesn't make sense, probably it was just
+  // copied over from the copy constructor. First, moving cannot fail due to
+  // OOM, second the condition is incorrect. Just because the implementation of
+  // nsStyleAutoArray's move constructor uses swapping, we do not seem to happen
+  // to run into the branch erroneously.
   uint32_t count = mLayers.Length();
   if (count != aOther.mLayers.Length()) {
     NS_WARNING("truncating counts due to out-of-memory");
diff --git a/layout/style/res/html.css b/layout/style/res/html.css
index 3fc451c036..c79b6534f1 100644
--- a/layout/style/res/html.css
+++ b/layout/style/res/html.css
@@ -828,6 +828,7 @@ dialog {
   padding: 1em;
   background: white;
   width: -moz-fit-content;
+  height: -moz-fit-content;
 }
 
 dialog:not([open]) {
@@ -836,6 +837,15 @@ dialog:not([open]) {
 
 dialog:-moz-modal-dialog {
   -moz-top-layer: top !important;
+  /* This is a temporary solution until the relevant CSSWG issues
+   * (https://github.com/w3c/csswg-drafts/issues/4645)
+   * are resolved. */
+  position: fixed;
+  max-height: 100vh;
+  max-width: 100vw;
+  top: 50%;
+  transform: translateY(-50%);
+  overflow: auto;
 }
 
 /* https://html.spec.whatwg.org/#flow-content-3 */
diff --git a/layout/style/res/ua.css b/layout/style/res/ua.css
index d1d3eab2cb..990c11e17d 100644
--- a/layout/style/res/ua.css
+++ b/layout/style/res/ua.css
@@ -354,6 +354,8 @@
   position: fixed;
   top: 0; left: 0;
   right: 0; bottom: 0;
+  /* This prevents undesired interactions with the selection code. */
+  user-select: none;
 }
 
 *|*:-moz-full-screen:not(:root)::backdrop {
diff --git a/layout/style/test/animation_utils.js b/layout/style/test/animation_utils.js
index 93e2979d42..33529f2743 100644
--- a/layout/style/test/animation_utils.js
+++ b/layout/style/test/animation_utils.js
@@ -395,11 +395,10 @@ function runOMTATest(aTestFunction, aOnSkip, specialPowersForPrefs) {
       }
       if (next.done) {
         return Promise.resolve(next.value);
-      } else {
-        return Promise.resolve(next.value).then(step, function(err) {
-          throw err;
-        });
       }
+      return Promise.resolve(next.value).then(step, function(err) {
+        throw err;
+      });
     }
 
     // Put refresh driver under test control
@@ -719,9 +718,8 @@ const ExpectComparisonTo = {
       return convertArrayTo3dMatrix(matrixLike);
     } else if (typeof matrixLike == "object") {
       return convertObjectTo3dMatrix(matrixLike);
-    } else {
-      return null;
     }
+    return null;
   };
 
   // In future most of these methods should be able to be replaced
@@ -771,9 +769,8 @@ const ExpectComparisonTo = {
         array.slice(8, 12),
         array.slice(12, 16),
       ];
-    } else {
-      return null;
     }
+    return null;
   }
 
   // Return the first defined value in args.
@@ -821,17 +818,16 @@ const ExpectComparisonTo = {
         ].join(", ") +
         ")"
       );
-    } else {
-      return (
-        "matrix3d(" +
-        matrix
-          .reduce(function(outer, inner) {
-            return outer.concat(inner);
-          })
-          .join(", ") +
-        ")"
-      );
     }
+    return (
+      "matrix3d(" +
+      matrix
+        .reduce(function(outer, inner) {
+          return outer.concat(inner);
+        })
+        .join(", ") +
+      ")"
+    );
   }
 
   function is2d(matrix) {
diff --git a/layout/style/test/bug1382568-iframe.html b/layout/style/test/bug1382568-iframe.html
index 63cbe3400e..b1448703e5 100644
--- a/layout/style/test/bug1382568-iframe.html
+++ b/layout/style/test/bug1382568-iframe.html
@@ -4,5 +4,5 @@
 window.addEventListener('load', function(){
   window[0].document.body.innerText;
   window.parent.postMessage({ result: "ok" }, "*");
-}, false);
+});
 </script>
diff --git a/layout/style/test/property_database.js b/layout/style/test/property_database.js
index b1363f1a60..4960c86d65 100644
--- a/layout/style/test/property_database.js
+++ b/layout/style/test/property_database.js
@@ -1,3 +1,4 @@
+/* eslint-disable dot-notation */
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
diff --git a/layout/style/test/test_flexbox_order.html b/layout/style/test/test_flexbox_order.html
index 368803657c..64b5431da8 100644
--- a/layout/style/test/test_flexbox_order.html
+++ b/layout/style/test/test_flexbox_order.html
@@ -175,7 +175,7 @@ function main() {
 
   // Initial sanity-check: should be in expected document order
   let initialSnapshot = snapshotWindow(window, false);
-  complainIfSnapshotsDiffer(initialSnapshot, gRefSnapshots["abc"],
+  complainIfSnapshotsDiffer(initialSnapshot, gRefSnapshots.abc,
                             "initial flex container rendering, " +
                             "no 'order' value yet");
 
diff --git a/layout/style/test/test_flexbox_order_abspos.html b/layout/style/test/test_flexbox_order_abspos.html
index 67d8bbbbf2..bf4c99aa76 100644
--- a/layout/style/test/test_flexbox_order_abspos.html
+++ b/layout/style/test/test_flexbox_order_abspos.html
@@ -198,7 +198,7 @@ function main() {
 
   // Initial sanity-check: should be in expected document order
   let initialSnapshot = snapshotWindow(window, false);
-  complainIfSnapshotsDiffer(initialSnapshot, gRefSnapshots["abc"],
+  complainIfSnapshotsDiffer(initialSnapshot, gRefSnapshots.abc,
                             "initial flex container rendering, " +
                             "no 'order' value yet");
 
diff --git a/layout/style/test/test_flexbox_order_table.html b/layout/style/test/test_flexbox_order_table.html
index 9cc1cb6cf8..2423d5d6d6 100644
--- a/layout/style/test/test_flexbox_order_table.html
+++ b/layout/style/test/test_flexbox_order_table.html
@@ -179,7 +179,7 @@ function main() {
 
   // Initial sanity-check: should be in expected document order
   let initialSnapshot = snapshotWindow(window, false);
-  complainIfSnapshotsDiffer(initialSnapshot, gRefSnapshots["abc"],
+  complainIfSnapshotsDiffer(initialSnapshot, gRefSnapshots.abc,
                             "initial flex container rendering, " +
                             "no 'order' value yet");
 
diff --git a/layout/style/test/test_garbage_at_end_of_declarations.html b/layout/style/test/test_garbage_at_end_of_declarations.html
index 15c464a36d..0e59867693 100644
--- a/layout/style/test/test_garbage_at_end_of_declarations.html
+++ b/layout/style/test/test_garbage_at_end_of_declarations.html
@@ -18,8 +18,10 @@
 <pre id="test">
 <script class="testbody" type="text/javascript">
 
+/* eslint-disable dot-notation */
 /** Test for correct ExpectEndProperty calls in CSS parser **/
 
+
 /*
  * Inspired by review comments on bug 378217.
  *
diff --git a/layout/style/test/test_position_float_display.html b/layout/style/test/test_position_float_display.html
index aa9d946abe..ee75144dcb 100644
--- a/layout/style/test/test_position_float_display.html
+++ b/layout/style/test/test_position_float_display.html
@@ -101,7 +101,7 @@ function test_display_value(val)
   }
 }
 
-var displayInfo = gCSSProperties["display"];
+var displayInfo = gCSSProperties.display;
 displayInfo.initial_values.forEach(test_display_value);
 displayInfo.other_values.forEach(test_display_value);
 
diff --git a/layout/style/test/test_root_node_display.html b/layout/style/test/test_root_node_display.html
index 3ae1ab6cf9..54dd9c222c 100644
--- a/layout/style/test/test_root_node_display.html
+++ b/layout/style/test/test_root_node_display.html
@@ -64,7 +64,7 @@ function test_display_value(val)
   }
 }
 
-var displayInfo = gCSSProperties["display"];
+var displayInfo = gCSSProperties.display;
 displayInfo.initial_values.forEach(test_display_value);
 displayInfo.other_values.forEach(test_display_value);
 
diff --git a/layout/style/test/test_transitions.html b/layout/style/test/test_transitions.html
index a25195f379..c26ba9be8f 100644
--- a/layout/style/test/test_transitions.html
+++ b/layout/style/test/test_transitions.html
@@ -642,7 +642,7 @@ function check_descendant_tests() {
     var values = {};
     values["text-indent"] = [ 50, 150 ];
     values["letter-spacing"] = [ 10, 5 ];
-    let tf = timingFunctions["ease"];
+    let tf = timingFunctions.ease;
 
     var time = px_to_num(earlyrefcs.textIndent) / REF_PX_PER_SEC;
 
@@ -721,7 +721,7 @@ function check_descendant_tests() {
 
 function check_number_tests()
 {
-    let tf = timingFunctions["ease"];
+    let tf = timingFunctions.ease;
     for (let d in number_tests) {
         let test = number_tests[d];
         let p = test.node;
diff --git a/layout/style/test/test_transitions_events.html b/layout/style/test/test_transitions_events.html
index 8e9564080e..b5838a6d2d 100644
--- a/layout/style/test/test_transitions_events.html
+++ b/layout/style/test/test_transitions_events.html
@@ -242,7 +242,7 @@ $("five").addEventListener("transitionstart", function() {
     did_finish_five = true;
   }
   $("five").style.transitionProperty = "margin-left";
-}, false);
+});
 
 $("six").addEventListener("transitionstart", function() {
   if (cs("six").color == "rgb(0, 255, 0)") {
@@ -252,7 +252,7 @@ $("six").addEventListener("transitionstart", function() {
   $("six").style.transitionDuration = "0s";
   $("six").style.transitionDelay = "0s";
   $("six").style.color = "blue";
-}, false);
+});
 
 function poll_start_reversal() {
   if (cs("four").color != "rgb(0, 0, 255)") {
diff --git a/layout/style/test/test_transitions_per_property.html b/layout/style/test/test_transitions_per_property.html
index 6d9ffb637a..199a9841af 100644
--- a/layout/style/test/test_transitions_per_property.html
+++ b/layout/style/test/test_transitions_per_property.html
@@ -42,6 +42,8 @@ https://bugzilla.mozilla.org/show_bug.cgi?id=435441
 <script type="application/javascript">
 
 /* eslint no-shadow: ["error", {"allow": ["prop", "div"]}] */
+/* eslint-disable dot-notation */
+
 
 /** Test for Bug 435441 **/
 
@@ -1834,10 +1836,9 @@ function test_shape_or_url_equals(computedValStr, expected)
   if (expectedList.length == 0) {
     if (computedValStr == "") {
       return true;
-    } else {
-      ok(false, "expected basic shape");
-      return false;
     }
+    ok(false, "expected basic shape");
+    return false;
   }
 
   // The regular expression does not filter out the last parenthesis.
diff --git a/layout/svg/SVGTextFrame.cpp b/layout/svg/SVGTextFrame.cpp
index b350898267..9b8918e0c7 100644
--- a/layout/svg/SVGTextFrame.cpp
+++ b/layout/svg/SVGTextFrame.cpp
@@ -1645,7 +1645,7 @@ nsTextFrame* TextFrameIterator::Next() {
           mCurrentPosition -= mCurrentFrame->GetPosition();
           if (mCurrentFrame->GetContent()->IsSVGElement(nsGkAtoms::textPath)) {
             // Pop off the <textPath> frame if this is a <textPath>.
-            mTextPathFrames.TruncateLength(mTextPathFrames.Length() - 1);
+            mTextPathFrames.RemoveLastElement();
           }
           // Pop off the current baseline.
           PopBaseline();
@@ -1692,7 +1692,7 @@ void TextFrameIterator::PushBaseline(nsIFrame* aNextFrame) {
 
 void TextFrameIterator::PopBaseline() {
   NS_ASSERTION(!mBaselines.IsEmpty(), "popped too many baselines");
-  mBaselines.TruncateLength(mBaselines.Length() - 1);
+  mBaselines.RemoveLastElement();
 }
 
 // -----------------------------------------------------------------------------
diff --git a/layout/tables/nsCellMap.cpp b/layout/tables/nsCellMap.cpp
index fe19344a8f..70d0b5bf7e 100644
--- a/layout/tables/nsCellMap.cpp
+++ b/layout/tables/nsCellMap.cpp
@@ -1949,8 +1949,7 @@ void nsCellMap::RebuildConsideringRows(
   NS_ASSERTION(!!aMap.mBCInfo == mIsBC, "BC state mismatch");
   // copy the old cell map into a new array
   uint32_t numOrigRows = mRows.Length();
-  nsTArray<CellDataArray> origRows;
-  mRows.SwapElements(origRows);
+  nsTArray<CellDataArray> origRows = std::move(mRows);
 
   int32_t rowNumberChange;
   if (aRowsToInsert) {
@@ -2049,8 +2048,7 @@ void nsCellMap::RebuildConsideringCells(
   NS_ASSERTION(!!aMap.mBCInfo == mIsBC, "BC state mismatch");
   // copy the old cell map into a new array
   int32_t numOrigRows = mRows.Length();
-  nsTArray<CellDataArray> origRows;
-  mRows.SwapElements(origRows);
+  nsTArray<CellDataArray> origRows = std::move(mRows);
 
   int32_t numNewCells = (aCellFrames) ? aCellFrames->Length() : 0;
 
diff --git a/layout/tables/nsTableFrame.cpp b/layout/tables/nsTableFrame.cpp
index cce2652436..1cd55e8b2b 100644
--- a/layout/tables/nsTableFrame.cpp
+++ b/layout/tables/nsTableFrame.cpp
@@ -570,7 +570,7 @@ void nsTableFrame::InsertCol(nsTableColFrame& aColFrame, int32_t aColIndex) {
           nsTableColType lastColType = lastCol->GetColType();
           if (eColAnonymousCell == lastColType) {
             // remove the col from the cache
-            mColFrames.RemoveElementAt(numCacheCols - 1);
+            mColFrames.RemoveLastElement();
             // remove the col from the synthetic col group
             nsTableColGroupFrame* lastColGroup =
                 (nsTableColGroupFrame*)mColGroups.LastChild();
diff --git a/layout/tools/reftest/runreftest.py b/layout/tools/reftest/runreftest.py
index 9d81be520a..e8c20f45cf 100644
--- a/layout/tools/reftest/runreftest.py
+++ b/layout/tools/reftest/runreftest.py
@@ -764,7 +764,7 @@ class RefTest(object):
             'processOutputLine': [self.outputHandler],
         }
 
-        if mozinfo.isWin:
+        if mozinfo.isWin or mozinfo.isMac:
             # Prevents log interleaving on Windows at the expense of losing
             # true log order. See bug 798300 and bug 1324961 for more details.
             kp_kwargs['processStderrLine'] = [self.outputHandler]
diff --git a/layout/xul/test/test_bug381167.xhtml b/layout/xul/test/test_bug381167.xhtml
index dca731e74b..1bf55f6fdb 100644
--- a/layout/xul/test/test_bug381167.xhtml
+++ b/layout/xul/test/test_bug381167.xhtml
@@ -36,7 +36,7 @@ function closeit() {
 
   setTimeout(finish, 200);
 }
-window.addEventListener('load', closeit, false);
+window.addEventListener('load', closeit);
 
 function finish()
 {
diff --git a/media/gmp-clearkey/0.1/ClearKeyDecryptionManager.cpp b/media/gmp-clearkey/0.1/ClearKeyDecryptionManager.cpp
index 888c567dc6..d8203b7bb6 100644
--- a/media/gmp-clearkey/0.1/ClearKeyDecryptionManager.cpp
+++ b/media/gmp-clearkey/0.1/ClearKeyDecryptionManager.cpp
@@ -212,7 +212,9 @@ Status ClearKeyDecryptor::Decrypt(uint8_t* aBuffer, uint32_t aBufferSize,
   std::vector<uint8_t> iv(aMetadata.mIV);
   iv.insert(iv.end(), CENC_KEY_LEN - aMetadata.mIV.size(), 0);
 
-  ClearKeyUtils::DecryptAES(mKey, tmp, iv);
+  if (!ClearKeyUtils::DecryptAES(mKey, tmp, iv)) {
+    return Status::kDecryptError;
+  }
 
   if (aMetadata.NumSubsamples()) {
     // Take the decrypted buffer, split up into subsamples, and insert those
diff --git a/media/gmp-clearkey/0.1/ClearKeyUtils.cpp b/media/gmp-clearkey/0.1/ClearKeyUtils.cpp
index aecfd82a9f..0f20e934c6 100644
--- a/media/gmp-clearkey/0.1/ClearKeyUtils.cpp
+++ b/media/gmp-clearkey/0.1/ClearKeyUtils.cpp
@@ -35,8 +35,10 @@
 // on Unix systems.
 #include "stddef.h"
 #include "content_decryption_module.h"
-#include "openaes/oaes_lib.h"
+#include "pk11pub.h"
+#include "prerror.h"
 #include "psshparser/PsshParser.h"
+#include "secmodt.h"
 
 using namespace cdm;
 
@@ -82,39 +84,46 @@ void CK_LogArray(const char* prepend, const uint8_t* aData,
   CK_LOGD("%s%s", prepend, data.c_str());
 }
 
-static void IncrementIV(vector<uint8_t>& aIV) {
-  using mozilla::BigEndian;
-
-  assert(aIV.size() == 16);
-  BigEndian::writeUint64(&aIV[8], BigEndian::readUint64(&aIV[8]) + 1);
-}
-
 /* static */
-void ClearKeyUtils::DecryptAES(const vector<uint8_t>& aKey,
+bool ClearKeyUtils::DecryptAES(const vector<uint8_t>& aKey,
                                vector<uint8_t>& aData, vector<uint8_t>& aIV) {
   assert(aIV.size() == CENC_KEY_LEN);
   assert(aKey.size() == CENC_KEY_LEN);
 
-  OAES_CTX* aes = oaes_alloc();
-  oaes_key_import_data(aes, &aKey[0], aKey.size());
-  oaes_set_option(aes, OAES_OPTION_ECB, nullptr);
-
-  for (size_t i = 0; i < aData.size(); i += CENC_KEY_LEN) {
-    size_t encLen;
-    oaes_encrypt(aes, &aIV[0], CENC_KEY_LEN, nullptr, &encLen);
-
-    vector<uint8_t> enc(encLen);
-    oaes_encrypt(aes, &aIV[0], CENC_KEY_LEN, &enc[0], &encLen);
-
-    assert(encLen >= 2 * OAES_BLOCK_SIZE + CENC_KEY_LEN);
-    size_t blockLen = std::min(aData.size() - i, CENC_KEY_LEN);
-    for (size_t j = 0; j < blockLen; j++) {
-      aData[i + j] ^= enc[2 * OAES_BLOCK_SIZE + j];
-    }
-    IncrementIV(aIV);
+  PK11SlotInfo* slot = PK11_GetInternalKeySlot();
+  if (!slot) {
+    CK_LOGE("Failed to get internal PK11 slot");
+    return false;
   }
 
-  oaes_free(&aes);
+  SECItem keyItem = {siBuffer, (unsigned char*)&aKey[0], CENC_KEY_LEN};
+  PK11SymKey* key = PK11_ImportSymKey(slot, CKM_AES_CTR, PK11_OriginUnwrap,
+                                      CKA_ENCRYPT, &keyItem, nullptr);
+  PK11_FreeSlot(slot);
+  if (!key) {
+    CK_LOGE("Failed to import sym key");
+    return false;
+  }
+
+  CK_AES_CTR_PARAMS params;
+  params.ulCounterBits = 32;
+  memcpy(&params.cb, &aIV[0], CENC_KEY_LEN);
+  SECItem paramItem = {siBuffer, (unsigned char*)&params,
+                       sizeof(CK_AES_CTR_PARAMS)};
+
+  unsigned int outLen = 0;
+  auto rv = PK11_Decrypt(key, CKM_AES_CTR, &paramItem, &aData[0], &outLen,
+                         aData.size(), &aData[0], aData.size());
+
+  aData.resize(outLen);
+  PK11_FreeSymKey(key);
+
+  if (rv != SECSuccess) {
+    CK_LOGE("PK11_Decrypt() failed");
+    return false;
+  }
+
+  return true;
 }
 
 /**
diff --git a/media/gmp-clearkey/0.1/ClearKeyUtils.h b/media/gmp-clearkey/0.1/ClearKeyUtils.h
index 3e8e22fa6c..32dbbc52cb 100644
--- a/media/gmp-clearkey/0.1/ClearKeyUtils.h
+++ b/media/gmp-clearkey/0.1/ClearKeyUtils.h
@@ -64,7 +64,7 @@ struct KeyIdPair {
 
 class ClearKeyUtils {
  public:
-  static void DecryptAES(const std::vector<uint8_t>& aKey,
+  static bool DecryptAES(const std::vector<uint8_t>& aKey,
                          std::vector<uint8_t>& aData,
                          std::vector<uint8_t>& aIV);
 
diff --git a/media/gmp-clearkey/0.1/gmp-clearkey.cpp b/media/gmp-clearkey/0.1/gmp-clearkey.cpp
index 0bf3509472..df0df97408 100644
--- a/media/gmp-clearkey/0.1/gmp-clearkey.cpp
+++ b/media/gmp-clearkey/0.1/gmp-clearkey.cpp
@@ -27,6 +27,7 @@
 #include "stddef.h"
 #include "content_decryption_module.h"
 #include "content_decryption_module_ext.h"
+#include "nss.h"
 
 #ifndef XP_WIN
 #  include <sys/types.h>
@@ -65,6 +66,11 @@ void* CreateCdmInstance(int cdm_interface_version, const char* key_system,
   }
 #endif
 
+  if (NSS_NoDB_Init(nullptr) == SECFailure) {
+    CK_LOGE("Unable to initialize NSS");
+    return nullptr;
+  }
+
 #ifdef MOZILLA_OFFICIAL
   // Test that we're able to read the host files.
   if (!sCanReadHostVerificationFiles) {
diff --git a/media/gmp-clearkey/0.1/moz.build b/media/gmp-clearkey/0.1/moz.build
index e162f6a273..427c7e60a8 100644
--- a/media/gmp-clearkey/0.1/moz.build
+++ b/media/gmp-clearkey/0.1/moz.build
@@ -53,7 +53,10 @@ TEST_DIRS += [
 DisableStlWrapping()
 DEFINES['MOZ_NO_MOZALLOC'] = True
 
-USE_LIBS += ['psshparser']
+USE_LIBS += [
+    'nss',
+    'psshparser',
+]
 
 # Suppress warnings in third-party code.
 CFLAGS += [
diff --git a/media/libsoundtouch/LICENSE b/media/libsoundtouch/LICENSE
index 5b2161be20..bbd24e6430 100644
--- a/media/libsoundtouch/LICENSE
+++ b/media/libsoundtouch/LICENSE
@@ -455,4 +455,4 @@ FAILURE OF THE LIBRARY TO OPERATE WITH ANY OTHER SOFTWARE), EVEN IF
 SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
 DAMAGES.
 
-		     END OF TERMS AND CONDITIONS
+		     END OF TERMS AND CONDITIONS
\ No newline at end of file
diff --git a/media/libsoundtouch/moz-libsoundtouch.patch b/media/libsoundtouch/moz-libsoundtouch.patch
index 87629373e8..dc2ea63804 100644
--- a/media/libsoundtouch/moz-libsoundtouch.patch
+++ b/media/libsoundtouch/moz-libsoundtouch.patch
@@ -56,7 +56,7 @@ diff -u /src/cpu_detect_x86.cpp /src/cpu_detect_x86.cpp
 diff -u /src/STTypes.h /src/STTypes.h
 --- /src/STTypes.h
 +++ /src/STTypes.h
-@@ -54,12 +54,13 @@
+@@ -54,12 +54,17 @@
  #define SOUNDTOUCH_ALIGN_POINTER_16(x)      ( ( (ulongptr)(x) + 15 ) & ~(ulongptr)15 )
  
  
@@ -68,9 +68,13 @@ diff -u /src/STTypes.h /src/STTypes.h
 +#include "soundtouch_config.h"
  
 +#if defined(WIN32)
-+#define EXPORT __declspec(dllexport)
++#if defined(BUILDING_SOUNDTOUCH)
++#define SOUNDTOUCH_API __declspec(dllexport)
 +#else
-+#define EXPORT
++#define SOUNDTOUCH_API __declspec(dllimport)
++#endif
++#else
++#define SOUNDTOUCH_API
 +#endif
  
  namespace soundtouch
@@ -83,7 +87,7 @@ diff -u /src/SoundTouch.h /src/SoundTouch.h
  #define SETTING_NOMINAL_OUTPUT_SEQUENCE		7
  
 -class SoundTouch : public FIFOProcessor
-+class EXPORT SoundTouch : public FIFOProcessor
++class SOUNDTOUCH_API SoundTouch : public FIFOProcessor
  {
  private:
      /// Rate transposer class instance
@@ -116,26 +120,17 @@ diff -u /src/TDStretch.cpp /src/TDStretch.cpp
 +#endif
  
      // Check if MMX/SSE instruction set extensions supported by CPU
- 
-diff --git a/media/libsoundtouch/src/AAFilter.cpp b/media/libsoundtouch/src/AAFilter.cpp
---- a/media/libsoundtouch/src/AAFilter.cpp
-+++ b/media/libsoundtouch/src/AAFilter.cpp
-@@ -44,17 +44,17 @@
- #include <assert.h>
- #include <math.h>
- #include <stdlib.h>
- #include "AAFilter.h"
- #include "FIRFilter.h"
+
+diff -u /src/AAFilter.cpp /src/AAFilter.cpp
+--- /src/AAFilter.cpp
++++ /src/AAFilter.cpp
+@@ -42,7 +42,7 @@
  
  using namespace soundtouch;
  
--#define PI        3.141592655357989
+-#define PI       3.14159265358979323846
 +#define PI       M_PI
  #define TWOPI    (2 * PI)
  
  // define this to save AA filter coefficients to a file
- // #define _DEBUG_SAVE_AAFILTER_COEFFICIENTS   1
- 
- #ifdef _DEBUG_SAVE_AAFILTER_COEFFICIENTS
-     #include <stdio.h>
  
diff --git a/media/libsoundtouch/moz.yaml b/media/libsoundtouch/moz.yaml
index 60ae124227..5bfce56d07 100644
--- a/media/libsoundtouch/moz.yaml
+++ b/media/libsoundtouch/moz.yaml
@@ -16,5 +16,5 @@ origin:
   url: "http://www.surina.net/soundtouch"
   license: "LGPL-2.1"
 
-  # from https://soundtouch.svn.sourceforge.net/svnroot/soundtouch/trunk
-  release: "r222"
+  # From https://gitlab.com/soundtouch/soundtouch
+  release: "17a63e99d58053b0fbde8b69d7cc76a38119ce70 (2021-03-03 18:11:45 +0200)"
diff --git a/media/libsoundtouch/src/AAFilter.cpp b/media/libsoundtouch/src/AAFilter.cpp
index b98a6d63ee..3fd4e9fe6d 100644
--- a/media/libsoundtouch/src/AAFilter.cpp
+++ b/media/libsoundtouch/src/AAFilter.cpp
@@ -12,13 +12,6 @@
 ///
 ////////////////////////////////////////////////////////////////////////////////
 //
-// Last changed  : $Date: 2014-01-05 21:40:22 +0000 (Sun, 05 Jan 2014) $
-// File revision : $Revision: 4 $
-//
-// $Id: AAFilter.cpp 177 2014-01-05 21:40:22Z oparviai $
-//
-////////////////////////////////////////////////////////////////////////////////
-//
 // License :
 //
 //  SoundTouch audio processing library
@@ -75,7 +68,6 @@ using namespace soundtouch;
     #define _DEBUG_SAVE_AAFIR_COEFFS(x, y)
 #endif
 
-
 /*****************************************************************************
  *
  * Implementation of the class 'AAFilter'
@@ -90,14 +82,12 @@ AAFilter::AAFilter(uint len)
 }
 
 
-
 AAFilter::~AAFilter()
 {
     delete pFIR;
 }
 
 
-
 // Sets new anti-alias filter cut-off edge frequency, scaled to
 // sampling frequency (nyquist frequency = 0.5).
 // The filter will cut frequencies higher than the given frequency.
@@ -108,7 +98,6 @@ void AAFilter::setCutoffFreq(double newCutoffFreq)
 }
 
 
-
 // Sets number of FIR filter taps
 void AAFilter::setLength(uint newLength)
 {
@@ -117,7 +106,6 @@ void AAFilter::setLength(uint newLength)
 }
 
 
-
 // Calculates coefficients for a low-pass FIR filter using Hamming window
 void AAFilter::calculateCoeffs()
 {
@@ -177,12 +165,10 @@ void AAFilter::calculateCoeffs()
     for (i = 0; i < length; i ++) 
     {
         temp = work[i] * scaleCoeff;
-//#if SOUNDTOUCH_INTEGER_SAMPLES
         // scale & round to nearest integer
         temp += (temp >= 0) ? 0.5 : -0.5;
         // ensure no overfloods
         assert(temp >= -32768 && temp <= 32767);
-//#endif
         coeffs[i] = (SAMPLETYPE)temp;
     }
 
diff --git a/media/libsoundtouch/src/AAFilter.h b/media/libsoundtouch/src/AAFilter.h
index f1b5f2a554..81d836b750 100644
--- a/media/libsoundtouch/src/AAFilter.h
+++ b/media/libsoundtouch/src/AAFilter.h
@@ -13,13 +13,6 @@
 ///
 ////////////////////////////////////////////////////////////////////////////////
 //
-// Last changed  : $Date: 2014-01-07 19:41:23 +0000 (Tue, 07 Jan 2014) $
-// File revision : $Revision: 4 $
-//
-// $Id: AAFilter.h 187 2014-01-07 19:41:23Z oparviai $
-//
-////////////////////////////////////////////////////////////////////////////////
-//
 // License :
 //
 //  SoundTouch audio processing library
diff --git a/media/libsoundtouch/src/FIFOSampleBuffer.cpp b/media/libsoundtouch/src/FIFOSampleBuffer.cpp
index 4e75c8a433..f15d65e124 100644
--- a/media/libsoundtouch/src/FIFOSampleBuffer.cpp
+++ b/media/libsoundtouch/src/FIFOSampleBuffer.cpp
@@ -15,13 +15,6 @@
 ///
 ////////////////////////////////////////////////////////////////////////////////
 //
-// Last changed  : $Date: 2012-11-08 18:53:01 +0000 (Thu, 08 Nov 2012) $
-// File revision : $Revision: 4 $
-//
-// $Id: FIFOSampleBuffer.cpp 160 2012-11-08 18:53:01Z oparviai $
-//
-////////////////////////////////////////////////////////////////////////////////
-//
 // License :
 //
 //  SoundTouch audio processing library
@@ -80,7 +73,8 @@ void FIFOSampleBuffer::setChannels(int numChannels)
 {
     uint usedBytes;
 
-    assert(numChannels > 0);
+    if (!verifyNumberOfChannels(numChannels)) return;
+
     usedBytes = channels * samplesInBuffer;
     channels = (uint)numChannels;
     samplesInBuffer = usedBytes / channels;
@@ -131,7 +125,7 @@ void FIFOSampleBuffer::putSamples(uint nSamples)
 //
 // Parameter 'slackCapacity' tells the function how much free capacity (in
 // terms of samples) there _at least_ should be, in order to the caller to
-// succesfully insert all the required samples to the buffer. When necessary, 
+// successfully insert all the required samples to the buffer. When necessary,
 // the function grows the buffer size to comply with this requirement.
 //
 // When using this function as means for inserting new samples, also remember 
@@ -158,7 +152,7 @@ SAMPLETYPE *FIFOSampleBuffer::ptrBegin()
 }
 
 
-// Ensures that the buffer has enought capacity, i.e. space for _at least_
+// Ensures that the buffer has enough capacity, i.e. space for _at least_
 // 'capacityRequirement' number of samples. The buffer is grown in steps of
 // 4 kilobytes to eliminate the need for frequently growing up the buffer,
 // as well as to round the buffer size up to the virtual memory page size.
@@ -272,3 +266,10 @@ uint FIFOSampleBuffer::adjustAmountOfSamples(uint numSamples)
     return samplesInBuffer;
 }
 
+
+/// Add silence to end of buffer
+void FIFOSampleBuffer::addSilent(uint nSamples)
+{
+    memset(ptrEnd(nSamples), 0, sizeof(SAMPLETYPE) * nSamples * channels);
+    samplesInBuffer += nSamples;
+}
diff --git a/media/libsoundtouch/src/FIFOSampleBuffer.h b/media/libsoundtouch/src/FIFOSampleBuffer.h
index 6d2fd59f65..e0b4f68c67 100644
--- a/media/libsoundtouch/src/FIFOSampleBuffer.h
+++ b/media/libsoundtouch/src/FIFOSampleBuffer.h
@@ -15,13 +15,6 @@
 ///
 ////////////////////////////////////////////////////////////////////////////////
 //
-// Last changed  : $Date: 2014-01-05 21:40:22 +0000 (Sun, 05 Jan 2014) $
-// File revision : $Revision: 4 $
-//
-// $Id: FIFOSampleBuffer.h 177 2014-01-05 21:40:22Z oparviai $
-//
-////////////////////////////////////////////////////////////////////////////////
-//
 // License :
 //
 //  SoundTouch audio processing library
@@ -119,7 +112,7 @@ public:
     /// 'putSamples(numSamples)' function.
     SAMPLETYPE *ptrEnd(
                 uint slackCapacity   ///< How much free capacity (in samples) there _at least_ 
-                                     ///< should be so that the caller can succesfully insert the 
+                                     ///< should be so that the caller can successfully insert the
                                      ///< desired samples to the buffer. If necessary, the function 
                                      ///< grows the buffer size to comply with this requirement.
                 );
@@ -177,6 +170,9 @@ public:
     /// allow trimming (downwards) amount of samples in pipeline.
     /// Returns adjusted amount of samples
     uint adjustAmountOfSamples(uint numSamples);
+
+    /// Add silence to end of buffer
+    void addSilent(uint nSamples);
 };
 
 }
diff --git a/media/libsoundtouch/src/FIFOSamplePipe.h b/media/libsoundtouch/src/FIFOSamplePipe.h
index cd3191c1af..3def42d1ab 100644
--- a/media/libsoundtouch/src/FIFOSamplePipe.h
+++ b/media/libsoundtouch/src/FIFOSamplePipe.h
@@ -17,13 +17,6 @@
 ///
 ////////////////////////////////////////////////////////////////////////////////
 //
-// Last changed  : $Date: 2012-06-13 19:29:53 +0000 (Wed, 13 Jun 2012) $
-// File revision : $Revision: 4 $
-//
-// $Id: FIFOSamplePipe.h 143 2012-06-13 19:29:53Z oparviai $
-//
-////////////////////////////////////////////////////////////////////////////////
-//
 // License :
 //
 //  SoundTouch audio processing library
@@ -58,6 +51,18 @@ namespace soundtouch
 /// Abstract base class for FIFO (first-in-first-out) sample processing classes.
 class FIFOSamplePipe
 {
+protected:
+
+    bool verifyNumberOfChannels(int nChannels) const
+    {
+        if ((nChannels > 0) && (nChannels <= SOUNDTOUCH_MAX_CHANNELS))
+        {
+            return true;
+        }
+        ST_THROW_RT_ERROR("Error: Illegal number of channels");
+        return false;
+    }
+
 public:
     // virtual default destructor
     virtual ~FIFOSamplePipe() {}
@@ -122,7 +127,6 @@ public:
 };
 
 
-
 /// Base-class for sound processing routines working in FIFO principle. With this base 
 /// class it's easy to implement sound processing stages that can be chained together,
 /// so that samples that are fed into beginning of the pipe automatically go through 
@@ -145,7 +149,6 @@ protected:
         output = pOutput;
     }
 
-
     /// Constructor. Doesn't define output pipe; it has to be set be 
     /// 'setOutPipe' function.
     FIFOProcessor()
@@ -153,7 +156,6 @@ protected:
         output = NULL;
     }
 
-
     /// Constructor. Configures output pipe.
     FIFOProcessor(FIFOSamplePipe *pOutput   ///< Output pipe.
                  )
@@ -161,13 +163,11 @@ protected:
         output = pOutput;
     }
 
-
     /// Destructor.
     virtual ~FIFOProcessor()
     {
     }
 
-
     /// Returns a pointer to the beginning of the output samples. 
     /// This function is provided for accessing the output samples directly. 
     /// Please be careful for not to corrupt the book-keeping!
@@ -194,7 +194,6 @@ public:
         return output->receiveSamples(outBuffer, maxSamples);
     }
 
-
     /// Adjusts book-keeping so that given number of samples are removed from beginning of the 
     /// sample buffer without copying them anywhere. 
     ///
@@ -206,14 +205,12 @@ public:
         return output->receiveSamples(maxSamples);
     }
 
-
     /// Returns number of samples currently available.
     virtual uint numSamples() const
     {
         return output->numSamples();
     }
 
-
     /// Returns nonzero if there aren't any samples available for outputting.
     virtual int isEmpty() const
     {
@@ -226,7 +223,6 @@ public:
     {
         return output->adjustAmountOfSamples(numSamples);
     }
-
 };
 
 }
diff --git a/media/libsoundtouch/src/FIRFilter.cpp b/media/libsoundtouch/src/FIRFilter.cpp
index dc7c4aa0ba..eec61a62bc 100644
--- a/media/libsoundtouch/src/FIRFilter.cpp
+++ b/media/libsoundtouch/src/FIRFilter.cpp
@@ -2,22 +2,21 @@
 ///
 /// General FIR digital filter routines with MMX optimization. 
 ///
-/// Note : MMX optimized functions reside in a separate, platform-specific file, 
+/// Notes : MMX optimized functions reside in a separate, platform-specific file,
 /// e.g. 'mmx_win.cpp' or 'mmx_gcc.cpp'
 ///
+/// This source file contains OpenMP optimizations that allow speeding up the
+/// corss-correlation algorithm by executing it in several threads / CPU cores
+/// in parallel. See the following article link for more detailed discussion
+/// about SoundTouch OpenMP optimizations:
+/// http://www.softwarecoven.com/parallel-computing-in-embedded-mobile-devices
+///
 /// Author        : Copyright (c) Olli Parviainen
 /// Author e-mail : oparviai 'at' iki.fi
 /// SoundTouch WWW: http://www.surina.net/soundtouch
 ///
 ////////////////////////////////////////////////////////////////////////////////
 //
-// Last changed  : $Date: 2015-02-21 21:24:29 +0000 (Sat, 21 Feb 2015) $
-// File revision : $Revision: 4 $
-//
-// $Id: FIRFilter.cpp 202 2015-02-21 21:24:29Z oparviai $
-//
-////////////////////////////////////////////////////////////////////////////////
-//
 // License :
 //
 //  SoundTouch audio processing library
@@ -61,14 +60,17 @@ FIRFilter::FIRFilter()
     length = 0;
     lengthDiv8 = 0;
     filterCoeffs = NULL;
+    filterCoeffsStereo = NULL;
 }
 
 
 FIRFilter::~FIRFilter()
 {
     delete[] filterCoeffs;
+    delete[] filterCoeffsStereo;
 }
 
+
 // Usual C-version of the filter routine for stereo sound
 uint FIRFilter::evaluateFilterStereo(SAMPLETYPE *dest, const SAMPLETYPE *src, uint numSamples) const
 {
@@ -78,35 +80,26 @@ uint FIRFilter::evaluateFilterStereo(SAMPLETYPE *dest, const SAMPLETYPE *src, ui
     // because division is much slower operation than multiplying.
     double dScaler = 1.0 / (double)resultDivider;
 #endif
+    // hint compiler autovectorization that loop length is divisible by 8
+    int ilength = length & -8;
 
-    assert(length != 0);
-    assert(src != NULL);
-    assert(dest != NULL);
-    assert(filterCoeffs != NULL);
+    assert((length != 0) && (length == ilength) && (src != NULL) && (dest != NULL) && (filterCoeffs != NULL));
 
-    end = 2 * (numSamples - length);
+    end = 2 * (numSamples - ilength);
 
     #pragma omp parallel for
-    for (j = 0; j < end; j += 2) 
+    for (j = 0; j < end; j += 2)
     {
         const SAMPLETYPE *ptr;
         LONG_SAMPLETYPE suml, sumr;
-        uint i;
 
         suml = sumr = 0;
         ptr = src + j;
 
-        for (i = 0; i < length; i += 4) 
+        for (int i = 0; i < ilength; i ++)
         {
-            // loop is unrolled by factor of 4 here for efficiency
-            suml += ptr[2 * i + 0] * filterCoeffs[i + 0] +
-                    ptr[2 * i + 2] * filterCoeffs[i + 1] +
-                    ptr[2 * i + 4] * filterCoeffs[i + 2] +
-                    ptr[2 * i + 6] * filterCoeffs[i + 3];
-            sumr += ptr[2 * i + 1] * filterCoeffs[i + 0] +
-                    ptr[2 * i + 3] * filterCoeffs[i + 1] +
-                    ptr[2 * i + 5] * filterCoeffs[i + 2] +
-                    ptr[2 * i + 7] * filterCoeffs[i + 3];
+            suml += ptr[2 * i] * filterCoeffsStereo[2 * i];
+            sumr += ptr[2 * i + 1] * filterCoeffsStereo[2 * i + 1];
         }
 
 #ifdef SOUNDTOUCH_INTEGER_SAMPLES
@@ -116,19 +109,14 @@ uint FIRFilter::evaluateFilterStereo(SAMPLETYPE *dest, const SAMPLETYPE *src, ui
         suml = (suml < -32768) ? -32768 : (suml > 32767) ? 32767 : suml;
         // saturate to 16 bit integer limits
         sumr = (sumr < -32768) ? -32768 : (sumr > 32767) ? 32767 : sumr;
-#else
-        suml *= dScaler;
-        sumr *= dScaler;
 #endif // SOUNDTOUCH_INTEGER_SAMPLES
         dest[j] = (SAMPLETYPE)suml;
         dest[j + 1] = (SAMPLETYPE)sumr;
     }
-    return numSamples - length;
+    return numSamples - ilength;
 }
 
 
-
-
 // Usual C-version of the filter routine for mono sound
 uint FIRFilter::evaluateFilterMono(SAMPLETYPE *dest, const SAMPLETYPE *src, uint numSamples) const
 {
@@ -139,31 +127,28 @@ uint FIRFilter::evaluateFilterMono(SAMPLETYPE *dest, const SAMPLETYPE *src, uint
     double dScaler = 1.0 / (double)resultDivider;
 #endif
 
-    assert(length != 0);
+    // hint compiler autovectorization that loop length is divisible by 8
+    int ilength = length & -8;
 
-    end = numSamples - length;
+    assert(ilength != 0);
+
+    end = numSamples - ilength;
     #pragma omp parallel for
-    for (j = 0; j < end; j ++) 
+    for (j = 0; j < end; j ++)
     {
         const SAMPLETYPE *pSrc = src + j;
         LONG_SAMPLETYPE sum;
-        uint i;
+        int i;
 
         sum = 0;
-        for (i = 0; i < length; i += 4) 
+        for (i = 0; i < ilength; i ++)
         {
-            // loop is unrolled by factor of 4 here for efficiency
-            sum += pSrc[i + 0] * filterCoeffs[i + 0] + 
-                   pSrc[i + 1] * filterCoeffs[i + 1] + 
-                   pSrc[i + 2] * filterCoeffs[i + 2] + 
-                   pSrc[i + 3] * filterCoeffs[i + 3];
+            sum += pSrc[i] * filterCoeffs[i];
         }
 #ifdef SOUNDTOUCH_INTEGER_SAMPLES
         sum >>= resultDivFactor;
         // saturate to 16 bit integer limits
         sum = (sum < -32768) ? -32768 : (sum > 32767) ? 32767 : sum;
-#else
-        sum *= dScaler;
 #endif // SOUNDTOUCH_INTEGER_SAMPLES
         dest[j] = (SAMPLETYPE)sum;
     }
@@ -187,14 +172,18 @@ uint FIRFilter::evaluateFilterMulti(SAMPLETYPE *dest, const SAMPLETYPE *src, uin
     assert(filterCoeffs != NULL);
     assert(numChannels < 16);
 
-    end = numChannels * (numSamples - length);
+    // hint compiler autovectorization that loop length is divisible by 8
+    int ilength = length & -8;
+
+    end = numChannels * (numSamples - ilength);
 
     #pragma omp parallel for
     for (j = 0; j < end; j += numChannels)
     {
         const SAMPLETYPE *ptr;
         LONG_SAMPLETYPE sums[16];
-        uint c, i;
+        uint c;
+        int i;
 
         for (c = 0; c < numChannels; c ++)
         {
@@ -203,7 +192,7 @@ uint FIRFilter::evaluateFilterMulti(SAMPLETYPE *dest, const SAMPLETYPE *src, uin
 
         ptr = src + j;
 
-        for (i = 0; i < length; i ++)
+        for (i = 0; i < ilength; i ++)
         {
             SAMPLETYPE coef=filterCoeffs[i];
             for (c = 0; c < numChannels; c ++)
@@ -217,13 +206,11 @@ uint FIRFilter::evaluateFilterMulti(SAMPLETYPE *dest, const SAMPLETYPE *src, uin
         {
 #ifdef SOUNDTOUCH_INTEGER_SAMPLES
             sums[c] >>= resultDivFactor;
-#else
-            sums[c] *= dScaler;
 #endif // SOUNDTOUCH_INTEGER_SAMPLES
             dest[j+c] = (SAMPLETYPE)sums[c];
         }
     }
-    return numSamples - length;
+    return numSamples - ilength;
 }
 
 
@@ -235,6 +222,13 @@ void FIRFilter::setCoefficients(const SAMPLETYPE *coeffs, uint newLength, uint u
     assert(newLength > 0);
     if (newLength % 8) ST_THROW_RT_ERROR("FIR filter length not divisible by 8");
 
+    #ifdef SOUNDTOUCH_FLOAT_SAMPLES
+        // scale coefficients already here if using floating samples
+        double scale = 1.0 / resultDivider;
+    #else
+        short scale = 1;
+    #endif
+
     lengthDiv8 = newLength / 8;
     length = lengthDiv8 * 8;
     assert(length == newLength);
@@ -244,7 +238,16 @@ void FIRFilter::setCoefficients(const SAMPLETYPE *coeffs, uint newLength, uint u
 
     delete[] filterCoeffs;
     filterCoeffs = new SAMPLETYPE[length];
-    memcpy(filterCoeffs, coeffs, length * sizeof(SAMPLETYPE));
+    delete[] filterCoeffsStereo;
+    filterCoeffsStereo = new SAMPLETYPE[length*2];
+    for (uint i = 0; i < length; i ++)
+    {
+        filterCoeffs[i] = (SAMPLETYPE)(coeffs[i] * scale);
+        // create also stereo set of filter coefficients: this allows compiler
+        // to autovectorize filter evaluation much more efficiently
+        filterCoeffsStereo[2 * i] = (SAMPLETYPE)(coeffs[i] * scale);
+        filterCoeffsStereo[2 * i + 1] = (SAMPLETYPE)(coeffs[i] * scale);
+    }
 }
 
 
@@ -254,7 +257,6 @@ uint FIRFilter::getLength() const
 }
 
 
-
 // Applies the filter to the given sequence of samples. 
 //
 // Note : The amount of outputted samples is by value of 'filter_length' 
@@ -284,7 +286,6 @@ uint FIRFilter::evaluate(SAMPLETYPE *dest, const SAMPLETYPE *src, uint numSample
 }
 
 
-
 // Operator 'new' is overloaded so that it automatically creates a suitable instance 
 // depending on if we've a MMX-capable CPU available or not.
 void * FIRFilter::operator new(size_t s)
diff --git a/media/libsoundtouch/src/FIRFilter.h b/media/libsoundtouch/src/FIRFilter.h
index 70ba97cfe5..39c2cc7542 100644
--- a/media/libsoundtouch/src/FIRFilter.h
+++ b/media/libsoundtouch/src/FIRFilter.h
@@ -11,13 +11,6 @@
 ///
 ////////////////////////////////////////////////////////////////////////////////
 //
-// Last changed  : $Date: 2015-02-21 21:24:29 +0000 (Sat, 21 Feb 2015) $
-// File revision : $Revision: 4 $
-//
-// $Id: FIRFilter.h 202 2015-02-21 21:24:29Z oparviai $
-//
-////////////////////////////////////////////////////////////////////////////////
-//
 // License :
 //
 //  SoundTouch audio processing library
@@ -64,6 +57,7 @@ protected:
 
     // Memory for filter coefficients
     SAMPLETYPE *filterCoeffs;
+    SAMPLETYPE *filterCoeffsStereo;
 
     virtual uint evaluateFilterStereo(SAMPLETYPE *dest, 
                                       const SAMPLETYPE *src, 
diff --git a/media/libsoundtouch/src/InterpolateCubic.cpp b/media/libsoundtouch/src/InterpolateCubic.cpp
index 8aa7374c74..b37b0fa801 100644
--- a/media/libsoundtouch/src/InterpolateCubic.cpp
+++ b/media/libsoundtouch/src/InterpolateCubic.cpp
@@ -8,10 +8,6 @@
 ///
 ////////////////////////////////////////////////////////////////////////////////
 //
-// $Id: InterpolateCubic.cpp 179 2014-01-06 18:41:42Z oparviai $
-//
-////////////////////////////////////////////////////////////////////////////////
-//
 // License :
 //
 //  SoundTouch audio processing library
diff --git a/media/libsoundtouch/src/InterpolateCubic.h b/media/libsoundtouch/src/InterpolateCubic.h
index e0e302b233..481abd64bc 100644
--- a/media/libsoundtouch/src/InterpolateCubic.h
+++ b/media/libsoundtouch/src/InterpolateCubic.h
@@ -8,10 +8,6 @@
 ///
 ////////////////////////////////////////////////////////////////////////////////
 //
-// $Id: InterpolateCubic.h 179 2014-01-06 18:41:42Z oparviai $
-//
-////////////////////////////////////////////////////////////////////////////////
-//
 // License :
 //
 //  SoundTouch audio processing library
@@ -45,7 +41,6 @@ namespace soundtouch
 class InterpolateCubic : public TransposerBase
 {
 protected:
-    virtual void resetRegisters();
     virtual int transposeMono(SAMPLETYPE *dest, 
                         const SAMPLETYPE *src, 
                         int &srcSamples);
@@ -56,10 +51,17 @@ protected:
                         const SAMPLETYPE *src, 
                         int &srcSamples);
 
-    float fract;
+    double fract;
 
 public:
     InterpolateCubic();
+
+    virtual void resetRegisters();
+
+    int getLatency() const
+    {
+        return 1;
+    }
 };
 
 }
diff --git a/media/libsoundtouch/src/InterpolateLinear.cpp b/media/libsoundtouch/src/InterpolateLinear.cpp
index ae26e69a1e..9533e79b79 100644
--- a/media/libsoundtouch/src/InterpolateLinear.cpp
+++ b/media/libsoundtouch/src/InterpolateLinear.cpp
@@ -8,10 +8,6 @@
 ///
 ////////////////////////////////////////////////////////////////////////////////
 //
-// $Id: InterpolateLinear.cpp 180 2014-01-06 19:16:02Z oparviai $
-//
-////////////////////////////////////////////////////////////////////////////////
-//
 // License :
 //
 //  SoundTouch audio processing library
@@ -146,7 +142,7 @@ int InterpolateLinearInteger::transposeMulti(SAMPLETYPE *dest, const SAMPLETYPE
         LONG_SAMPLETYPE temp, vol1;
     
         assert(iFract < SCALE);
-        vol1 = (SCALE - iFract);
+        vol1 = (LONG_SAMPLETYPE)(SCALE - iFract);
         for (int c = 0; c < numChannels; c ++)
         {
             temp = vol1 * src[c] + iFract * src[c + numChannels];
@@ -170,9 +166,9 @@ int InterpolateLinearInteger::transposeMulti(SAMPLETYPE *dest, const SAMPLETYPE
 
 // Sets new target iRate. Normal iRate = 1.0, smaller values represent slower 
 // iRate, larger faster iRates.
-void InterpolateLinearInteger::setRate(float newRate)
+void InterpolateLinearInteger::setRate(double newRate)
 {
-    iRate = (int)(newRate * SCALE + 0.5f);
+    iRate = (int)(newRate * SCALE + 0.5);
     TransposerBase::setRate(newRate);
 }
 
@@ -190,7 +186,7 @@ InterpolateLinearFloat::InterpolateLinearFloat() : TransposerBase()
     // Notice: use local function calling syntax for sake of clarity, 
     // to indicate the fact that C++ constructor can't call virtual functions.
     resetRegisters();
-    setRate(1.0f);
+    setRate(1.0);
 }
 
 
@@ -275,12 +271,13 @@ int InterpolateLinearFloat::transposeMulti(SAMPLETYPE *dest, const SAMPLETYPE *s
     i = 0;
     while (srcCount < srcSampleEnd)
     {
-        float temp, vol1;
+        float temp, vol1, fract_float;
     
-        vol1 = (1.0f- fract);
+        vol1 = (float)(1.0 - fract);
+		fract_float = (float)fract;
         for (int c = 0; c < numChannels; c ++)
         {
-            temp = vol1 * src[c] + fract * src[c + numChannels];
+			temp = vol1 * src[c] + fract_float * src[c + numChannels];
             *dest = (SAMPLETYPE)temp;
             dest ++;
         }
diff --git a/media/libsoundtouch/src/InterpolateLinear.h b/media/libsoundtouch/src/InterpolateLinear.h
index b76299f889..ff362e84b1 100644
--- a/media/libsoundtouch/src/InterpolateLinear.h
+++ b/media/libsoundtouch/src/InterpolateLinear.h
@@ -8,10 +8,6 @@
 ///
 ////////////////////////////////////////////////////////////////////////////////
 //
-// $Id: InterpolateLinear.h 179 2014-01-06 18:41:42Z oparviai $
-//
-////////////////////////////////////////////////////////////////////////////////
-//
 // License :
 //
 //  SoundTouch audio processing library
@@ -42,15 +38,13 @@
 namespace soundtouch
 {
 
-/// Linear transposer class that uses integer arithmetics
+/// Linear transposer class that uses integer arithmetic
 class InterpolateLinearInteger : public TransposerBase
 {
 protected:
     int iFract;
     int iRate;
 
-    virtual void resetRegisters();
-
     virtual int transposeMono(SAMPLETYPE *dest, 
                        const SAMPLETYPE *src, 
                        int &srcSamples);
@@ -63,17 +57,22 @@ public:
 
     /// Sets new target rate. Normal rate = 1.0, smaller values represent slower 
     /// rate, larger faster rates.
-    virtual void setRate(float newRate);
+    virtual void setRate(double newRate);
+
+    virtual void resetRegisters();
+
+    int getLatency() const
+    {
+        return 0;
+    }
 };
 
 
-/// Linear transposer class that uses floating point arithmetics
+/// Linear transposer class that uses floating point arithmetic
 class InterpolateLinearFloat : public TransposerBase
 {
 protected:
-    float fract;
-
-    virtual void resetRegisters();
+    double fract;
 
     virtual int transposeMono(SAMPLETYPE *dest, 
                        const SAMPLETYPE *src, 
@@ -85,6 +84,13 @@ protected:
 
 public:
     InterpolateLinearFloat();
+
+    virtual void resetRegisters();
+
+    int getLatency() const
+    {
+        return 0;
+    }
 };
 
 }
diff --git a/media/libsoundtouch/src/InterpolateShannon.cpp b/media/libsoundtouch/src/InterpolateShannon.cpp
index 1085fd14cb..975d872ad6 100644
--- a/media/libsoundtouch/src/InterpolateShannon.cpp
+++ b/media/libsoundtouch/src/InterpolateShannon.cpp
@@ -13,10 +13,6 @@
 ///
 ////////////////////////////////////////////////////////////////////////////////
 //
-// $Id: InterpolateShannon.cpp 195 2014-04-06 15:57:21Z oparviai $
-//
-////////////////////////////////////////////////////////////////////////////////
-//
 // License :
 //
 //  SoundTouch audio processing library
diff --git a/media/libsoundtouch/src/InterpolateShannon.h b/media/libsoundtouch/src/InterpolateShannon.h
index 701640f7db..72ab0b526d 100644
--- a/media/libsoundtouch/src/InterpolateShannon.h
+++ b/media/libsoundtouch/src/InterpolateShannon.h
@@ -13,10 +13,6 @@
 ///
 ////////////////////////////////////////////////////////////////////////////////
 //
-// $Id: InterpolateShannon.h 179 2014-01-06 18:41:42Z oparviai $
-//
-////////////////////////////////////////////////////////////////////////////////
-//
 // License :
 //
 //  SoundTouch audio processing library
@@ -50,7 +46,6 @@ namespace soundtouch
 class InterpolateShannon : public TransposerBase
 {
 protected:
-    void resetRegisters();
     int transposeMono(SAMPLETYPE *dest, 
                         const SAMPLETYPE *src, 
                         int &srcSamples);
@@ -61,10 +56,17 @@ protected:
                         const SAMPLETYPE *src, 
                         int &srcSamples);
 
-    float fract;
+    double fract;
 
 public:
     InterpolateShannon();
+
+    void resetRegisters();
+
+    int getLatency() const
+    {
+        return 3;
+    }
 };
 
 }
diff --git a/media/libsoundtouch/src/RateTransposer.cpp b/media/libsoundtouch/src/RateTransposer.cpp
index f1e3fd043b..561ae43c52 100644
--- a/media/libsoundtouch/src/RateTransposer.cpp
+++ b/media/libsoundtouch/src/RateTransposer.cpp
@@ -10,13 +10,6 @@
 ///
 ////////////////////////////////////////////////////////////////////////////////
 //
-// Last changed  : $Date: 2014-04-06 15:57:21 +0000 (Sun, 06 Apr 2014) $
-// File revision : $Revision: 4 $
-//
-// $Id: RateTransposer.cpp 195 2014-04-06 15:57:21Z oparviai $
-//
-////////////////////////////////////////////////////////////////////////////////
-//
 // License :
 //
 //  SoundTouch audio processing library
@@ -57,15 +50,21 @@ TransposerBase::ALGORITHM TransposerBase::algorithm = TransposerBase::CUBIC;
 // Constructor
 RateTransposer::RateTransposer() : FIFOProcessor(&outputBuffer)
 {
-    bUseAAFilter = true;
+    bUseAAFilter =
+#ifndef SOUNDTOUCH_PREVENT_CLICK_AT_RATE_CROSSOVER
+        true;
+#else
+        // Disable Anti-alias filter if desirable to avoid click at rate change zero value crossover
+        false;
+#endif
 
     // Instantiates the anti-alias filter
     pAAFilter = new AAFilter(64);
     pTransposer = TransposerBase::newInstance();
+    clear();
 }
 
 
-
 RateTransposer::~RateTransposer()
 {
     delete pAAFilter;
@@ -73,11 +72,14 @@ RateTransposer::~RateTransposer()
 }
 
 
-
 /// Enables/disables the anti-alias filter. Zero to disable, nonzero to enable
 void RateTransposer::enableAAFilter(bool newMode)
 {
+#ifndef SOUNDTOUCH_PREVENT_CLICK_AT_RATE_CROSSOVER
+    // Disable Anti-alias filter if desirable to avoid click at rate change zero value crossover
     bUseAAFilter = newMode;
+    clear();
+#endif
 }
 
 
@@ -94,23 +96,22 @@ AAFilter *RateTransposer::getAAFilter()
 }
 
 
-
 // Sets new target iRate. Normal iRate = 1.0, smaller values represent slower 
 // iRate, larger faster iRates.
-void RateTransposer::setRate(float newRate)
+void RateTransposer::setRate(double newRate)
 {
     double fCutoff;
 
     pTransposer->setRate(newRate);
 
     // design a new anti-alias filter
-    if (newRate > 1.0f) 
+    if (newRate > 1.0)
     {
-        fCutoff = 0.5f / newRate;
+        fCutoff = 0.5 / newRate;
     } 
     else 
     {
-        fCutoff = 0.5f * newRate;
+        fCutoff = 0.5 * newRate;
     }
     pAAFilter->setCutoffFreq(fCutoff);
 }
@@ -177,11 +178,10 @@ void RateTransposer::processSamples(const SAMPLETYPE *src, uint nSamples)
 // Sets the number of channels, 1 = mono, 2 = stereo
 void RateTransposer::setChannels(int nChannels)
 {
-    assert(nChannels > 0);
+    if (!verifyNumberOfChannels(nChannels) ||
+        (pTransposer->numChannels == nChannels)) return;
 
-    if (pTransposer->numChannels == nChannels) return;
     pTransposer->setChannels(nChannels);
-
     inputBuffer.setChannels(nChannels);
     midBuffer.setChannels(nChannels);
     outputBuffer.setChannels(nChannels);
@@ -194,6 +194,11 @@ void RateTransposer::clear()
     outputBuffer.clear();
     midBuffer.clear();
     inputBuffer.clear();
+    pTransposer->resetRegisters();
+
+    // prefill buffer to avoid losing first samples at beginning of stream
+    int prefill = getLatency();
+    inputBuffer.addSilent(prefill);
 }
 
 
@@ -208,6 +213,14 @@ int RateTransposer::isEmpty() const
 }
 
 
+/// Return approximate initial input-output latency
+int RateTransposer::getLatency() const
+{
+    return pTransposer->getLatency() +
+        ((bUseAAFilter) ? (pAAFilter->getLength() / 2) : 0);
+}
+
+
 //////////////////////////////////////////////////////////////////////////////
 //
 // TransposerBase - Base class for interpolation
@@ -225,7 +238,7 @@ void TransposerBase::setAlgorithm(TransposerBase::ALGORITHM a)
 int TransposerBase::transpose(FIFOSampleBuffer &dest, FIFOSampleBuffer &src)
 {
     int numSrcSamples = src.numSamples();
-    int sizeDemand = (int)((float)numSrcSamples / rate) + 8;
+    int sizeDemand = (int)((double)numSrcSamples / rate) + 8;
     int numOutput;
     SAMPLETYPE *psrc = src.ptrBegin();
     SAMPLETYPE *pdest = dest.ptrEnd(sizeDemand);
@@ -270,7 +283,7 @@ void TransposerBase::setChannels(int channels)
 }
 
 
-void TransposerBase::setRate(float newRate)
+void TransposerBase::setRate(double newRate)
 {
     rate = newRate;
 }
@@ -280,7 +293,7 @@ void TransposerBase::setRate(float newRate)
 TransposerBase *TransposerBase::newInstance()
 {
 #ifdef SOUNDTOUCH_INTEGER_SAMPLES
-    // Notice: For integer arithmetics support only linear algorithm (due to simplest calculus)
+    // Notice: For integer arithmetic support only linear algorithm (due to simplest calculus)
     return ::new InterpolateLinearInteger;
 #else
     switch (algorithm)
diff --git a/media/libsoundtouch/src/RateTransposer.h b/media/libsoundtouch/src/RateTransposer.h
index fad6d65718..59381fab5f 100644
--- a/media/libsoundtouch/src/RateTransposer.h
+++ b/media/libsoundtouch/src/RateTransposer.h
@@ -14,13 +14,6 @@
 ///
 ////////////////////////////////////////////////////////////////////////////////
 //
-// Last changed  : $Date: 2014-04-06 15:57:21 +0000 (Sun, 06 Apr 2014) $
-// File revision : $Revision: 4 $
-//
-// $Id: RateTransposer.h 195 2014-04-06 15:57:21Z oparviai $
-//
-////////////////////////////////////////////////////////////////////////////////
-//
 // License :
 //
 //  SoundTouch audio processing library
@@ -66,8 +59,6 @@ public:
     };
 
 protected:
-    virtual void resetRegisters() = 0;
-
     virtual int transposeMono(SAMPLETYPE *dest, 
                         const SAMPLETYPE *src, 
                         int &srcSamples)  = 0;
@@ -81,15 +72,18 @@ protected:
     static ALGORITHM algorithm;
 
 public:
-    float rate;
+    double rate;
     int numChannels;
 
     TransposerBase();
     virtual ~TransposerBase();
 
     virtual int transpose(FIFOSampleBuffer &dest, FIFOSampleBuffer &src);
-    virtual void setRate(float newRate);
+    virtual void setRate(double newRate);
     virtual void setChannels(int channels);
+    virtual int getLatency() const = 0;
+
+    virtual void resetRegisters() = 0;
 
     // static factory function
     static TransposerBase *newInstance();
@@ -132,21 +126,9 @@ public:
     RateTransposer();
     virtual ~RateTransposer();
 
-    /// Operator 'new' is overloaded so that it automatically creates a suitable instance 
-    /// depending on if we're to use integer or floating point arithmetics.
-//    static void *operator new(size_t s);
-
-    /// Use this function instead of "new" operator to create a new instance of this class. 
-    /// This function automatically chooses a correct implementation, depending on if 
-    /// integer ot floating point arithmetics are to be used.
-//    static RateTransposer *newInstance();
-
     /// Returns the output buffer object
     FIFOSamplePipe *getOutput() { return &outputBuffer; };
 
-    /// Returns the store buffer object
-//    FIFOSamplePipe *getStore() { return &storeBuffer; };
-
     /// Return anti-alias filter object
     AAFilter *getAAFilter();
 
@@ -158,7 +140,7 @@ public:
 
     /// Sets new target rate. Normal rate = 1.0, smaller values represent slower 
     /// rate, larger faster rates.
-    virtual void setRate(float newRate);
+    virtual void setRate(double newRate);
 
     /// Sets the number of channels, 1 = mono, 2 = stereo
     void setChannels(int channels);
@@ -172,6 +154,9 @@ public:
 
     /// Returns nonzero if there aren't any samples available for outputting.
     int isEmpty() const;
+
+    /// Return approximate initial input-output latency
+    int getLatency() const;
 };
 
 }
diff --git a/media/libsoundtouch/src/STTypes.h b/media/libsoundtouch/src/STTypes.h
index b120f63a77..1dcfa736c4 100644
--- a/media/libsoundtouch/src/STTypes.h
+++ b/media/libsoundtouch/src/STTypes.h
@@ -8,13 +8,6 @@
 ///
 ////////////////////////////////////////////////////////////////////////////////
 //
-// Last changed  : $Date: 2015-05-18 15:25:07 +0000 (Mon, 18 May 2015) $
-// File revision : $Revision: 3 $
-//
-// $Id: STTypes.h 215 2015-05-18 15:25:07Z oparviai $
-//
-////////////////////////////////////////////////////////////////////////////////
-//
 // License :
 //
 //  SoundTouch audio processing library
@@ -57,13 +50,20 @@ typedef unsigned long   ulong;
 #include "soundtouch_config.h"
 
 #if defined(WIN32)
-#define EXPORT __declspec(dllexport)
+#if defined(BUILDING_SOUNDTOUCH)
+#define SOUNDTOUCH_API __declspec(dllexport)
 #else
-#define EXPORT
+#define SOUNDTOUCH_API __declspec(dllimport)
+#endif
+#else
+#define SOUNDTOUCH_API
 #endif
 
 namespace soundtouch
 {
+    /// Max allowed number of channels
+    #define SOUNDTOUCH_MAX_CHANNELS     16
+
     /// Activate these undef's to overrule the possible sampletype 
     /// setting inherited from some other header file:
     //#undef SOUNDTOUCH_INTEGER_SAMPLES
@@ -126,10 +126,10 @@ namespace soundtouch
 
     #endif
 
-    // If defined, allows the SIMD-optimized routines to take minor shortcuts 
-    // for improved performance. Undefine to require faithfully similar SIMD 
-    // calculations as in normal C implementation.
-    #define SOUNDTOUCH_ALLOW_NONEXACT_SIMD_OPTIMIZATION    1
+    // If defined, allows the SIMD-optimized routines to skip unevenly aligned
+    // memory offsets that can cause performance penalty in some SIMD implementations.
+    // Causes slight compromise in sound quality.
+    // #define SOUNDTOUCH_ALLOW_NONEXACT_SIMD_OPTIMIZATION    1
 
 
     #ifdef SOUNDTOUCH_INTEGER_SAMPLES
@@ -144,16 +144,19 @@ namespace soundtouch
         #endif // SOUNDTOUCH_FLOAT_SAMPLES
 
         #ifdef SOUNDTOUCH_ALLOW_X86_OPTIMIZATIONS
-            // Allow MMX optimizations
-            #define SOUNDTOUCH_ALLOW_MMX   1
+            // Allow MMX optimizations (not available in X64 mode)
+            #if (!_M_X64)
+                #define SOUNDTOUCH_ALLOW_MMX   1
+            #endif
         #endif
 
     #else
 
         // floating point samples
         typedef float  SAMPLETYPE;
-        // data type for sample accumulation: Use double to utilize full precision.
-        typedef double LONG_SAMPLETYPE;
+        // data type for sample accumulation: Use float also here to enable
+        // efficient autovectorization
+        typedef float LONG_SAMPLETYPE;
 
         #if defined(SOUNDTOUCH_ALLOW_X86_OPTIMIZATIONS) && !defined(THE_SSE1)
             // Allow SSE optimizations
@@ -162,6 +165,12 @@ namespace soundtouch
 
     #endif  // SOUNDTOUCH_INTEGER_SAMPLES
 
+    #if ((SOUNDTOUCH_ALLOW_SSE) || (__SSE__) || (SOUNDTOUCH_USE_NEON))
+        #if SOUNDTOUCH_ALLOW_NONEXACT_SIMD_OPTIMIZATION
+            #define ST_SIMD_AVOID_UNALIGNED
+        #endif
+    #endif
+
 };
 
 // define ST_NO_EXCEPTION_HANDLING switch to disable throwing std exceptions:
diff --git a/media/libsoundtouch/src/SoundTouch.cpp b/media/libsoundtouch/src/SoundTouch.cpp
index a9d23fc3c3..bf024e8086 100644
--- a/media/libsoundtouch/src/SoundTouch.cpp
+++ b/media/libsoundtouch/src/SoundTouch.cpp
@@ -41,13 +41,6 @@
 ///
 ////////////////////////////////////////////////////////////////////////////////
 //
-// Last changed  : $Date: 2014-10-08 15:26:57 +0000 (Wed, 08 Oct 2014) $
-// File revision : $Revision: 4 $
-//
-// $Id: SoundTouch.cpp 201 2014-10-08 15:26:57Z oparviai $
-//
-////////////////////////////////////////////////////////////////////////////////
-//
 // License :
 //
 //  SoundTouch audio processing library
@@ -110,12 +103,14 @@ SoundTouch::SoundTouch()
 
     calcEffectiveRateAndTempo();
 
+    samplesExpectedOut = 0;
+    samplesOutput = 0;
+
     channels = 0;
     bSrateSet = false;
 }
 
 
-
 SoundTouch::~SoundTouch()
 {
     delete pRateTransposer;
@@ -123,7 +118,6 @@ SoundTouch::~SoundTouch()
 }
 
 
-
 /// Get SoundTouch library version string
 const char *SoundTouch::getVersionString()
 {
@@ -143,90 +137,79 @@ uint SoundTouch::getVersionId()
 // Sets the number of channels, 1 = mono, 2 = stereo
 void SoundTouch::setChannels(uint numChannels)
 {
-    /*if (numChannels != 1 && numChannels != 2) 
-    {
-        //ST_THROW_RT_ERROR("Illegal number of channels");
-		return;
-    }*/
+    if (!verifyNumberOfChannels(numChannels)) return;
+
     channels = numChannels;
     pRateTransposer->setChannels((int)numChannels);
     pTDStretch->setChannels((int)numChannels);
 }
 
 
-
 // Sets new rate control value. Normal rate = 1.0, smaller values
 // represent slower rate, larger faster rates.
-void SoundTouch::setRate(float newRate)
+void SoundTouch::setRate(double newRate)
 {
     virtualRate = newRate;
     calcEffectiveRateAndTempo();
 }
 
 
-
 // Sets new rate control value as a difference in percents compared
 // to the original rate (-50 .. +100 %)
-void SoundTouch::setRateChange(float newRate)
+void SoundTouch::setRateChange(double newRate)
 {
-    virtualRate = 1.0f + 0.01f * newRate;
+    virtualRate = 1.0 + 0.01 * newRate;
     calcEffectiveRateAndTempo();
 }
 
 
-
 // Sets new tempo control value. Normal tempo = 1.0, smaller values
 // represent slower tempo, larger faster tempo.
-void SoundTouch::setTempo(float newTempo)
+void SoundTouch::setTempo(double newTempo)
 {
     virtualTempo = newTempo;
     calcEffectiveRateAndTempo();
 }
 
 
-
 // Sets new tempo control value as a difference in percents compared
 // to the original tempo (-50 .. +100 %)
-void SoundTouch::setTempoChange(float newTempo)
+void SoundTouch::setTempoChange(double newTempo)
 {
-    virtualTempo = 1.0f + 0.01f * newTempo;
+    virtualTempo = 1.0 + 0.01 * newTempo;
     calcEffectiveRateAndTempo();
 }
 
 
-
 // Sets new pitch control value. Original pitch = 1.0, smaller values
 // represent lower pitches, larger values higher pitch.
-void SoundTouch::setPitch(float newPitch)
+void SoundTouch::setPitch(double newPitch)
 {
     virtualPitch = newPitch;
     calcEffectiveRateAndTempo();
 }
 
 
-
 // Sets pitch change in octaves compared to the original pitch
 // (-1.00 .. +1.00)
-void SoundTouch::setPitchOctaves(float newPitch)
+void SoundTouch::setPitchOctaves(double newPitch)
 {
-    virtualPitch = (float)exp(0.69314718056f * newPitch);
+    virtualPitch = exp(0.69314718056 * newPitch);
     calcEffectiveRateAndTempo();
 }
 
 
-
 // Sets pitch change in semi-tones compared to the original pitch
 // (-12 .. +12)
 void SoundTouch::setPitchSemiTones(int newPitch)
 {
-    setPitchOctaves((float)newPitch / 12.0f);
+    setPitchOctaves((double)newPitch / 12.0);
 }
 
 
-
-void SoundTouch::setPitchSemiTones(float newPitch)
+void SoundTouch::setPitchSemiTones(double newPitch)
 {
-    setPitchOctaves(newPitch / 12.0f);
+    setPitchOctaves(newPitch / 12.0);
 }
 
 
@@ -234,8 +217,8 @@ void SoundTouch::setPitchSemiTones(float newPitch)
 // nominal control values.
 void SoundTouch::calcEffectiveRateAndTempo()
 {
-    float oldTempo = tempo;
-    float oldRate = rate;
+    double oldTempo = tempo;
+    double oldRate = rate;
 
     tempo = virtualTempo / virtualPitch;
     rate = virtualPitch * virtualRate;
@@ -283,9 +266,9 @@ void SoundTouch::calcEffectiveRateAndTempo()
 // Sets sample rate.
 void SoundTouch::setSampleRate(uint srate)
 {
-    bSrateSet = true;
     // set sample rate, leave other tempo changer parameters as they are.
     pTDStretch->setParameters((int)srate);
+    bSrateSet = true;
 }
 
 
@@ -302,23 +285,12 @@ void SoundTouch::putSamples(const SAMPLETYPE *samples, uint nSamples)
         ST_THROW_RT_ERROR("SoundTouch : Number of channels not defined");
     }
 
-    // Transpose the rate of the new samples if necessary
-    /* Bypass the nominal setting - can introduce a click in sound when tempo/pitch control crosses the nominal value...
-    if (rate == 1.0f) 
-    {
-        // The rate value is same as the original, simply evaluate the tempo changer. 
-        assert(output == pTDStretch);
-        if (pRateTransposer->isEmpty() == 0) 
-        {
-            // yet flush the last samples in the pitch transposer buffer
-            // (may happen if 'rate' changes from a non-zero value to zero)
-            pTDStretch->moveSamples(*pRateTransposer);
-        }
-        pTDStretch->putSamples(samples, nSamples);
-    } 
-    */
+    // accumulate how many samples are expected out from processing, given the current
+    // processing setting
+    samplesExpectedOut += (double)nSamples / ((double)rate * (double)tempo);
+
 #ifndef SOUNDTOUCH_PREVENT_CLICK_AT_RATE_CROSSOVER
-    else if (rate <= 1.0f) 
+    if (rate <= 1.0f)
     {
         // transpose the rate down, output the transposed sound to tempo changer buffer
         assert(output == pTDStretch);
@@ -346,44 +318,30 @@ void SoundTouch::putSamples(const SAMPLETYPE *samples, uint nSamples)
 void SoundTouch::flush()
 {
     int i;
-    int nUnprocessed;
-    int nOut;
-    SAMPLETYPE *buff = new SAMPLETYPE[64 * channels];
-    
-    // check how many samples still await processing, and scale
-    // that by tempo & rate to get expected output sample count
-    nUnprocessed = numUnprocessedSamples();
-    nUnprocessed = (int)((double)nUnprocessed / (tempo * rate) + 0.5);
+    int numStillExpected;
+    SAMPLETYPE *buff = new SAMPLETYPE[128 * channels];
 
-    nOut = numSamples();        // ready samples currently in buffer ...
-    nOut += nUnprocessed;       // ... and how many we expect there to be in the end
-    
-    memset(buff, 0, 64 * channels * sizeof(SAMPLETYPE));
+    // how many samples are still expected to output
+    numStillExpected = (int)((long)(samplesExpectedOut + 0.5) - samplesOutput);
+    if (numStillExpected < 0) numStillExpected = 0;
+
+    memset(buff, 0, 128 * channels * sizeof(SAMPLETYPE));
     // "Push" the last active samples out from the processing pipeline by
     // feeding blank samples into the processing pipeline until new, 
     // processed samples appear in the output (not however, more than 
-    // 8ksamples in any case)
-    for (i = 0; i < 128; i ++) 
+    // 24ksamples in any case)
+    for (i = 0; (numStillExpected > (int)numSamples()) && (i < 200); i ++)
     {
-        putSamples(buff, 64);
-        if ((int)numSamples() >= nOut) 
-        {
-            // Enough new samples have appeared into the output!
-            // As samples come from processing with bigger chunks, now truncate it
-            // back to maximum "nOut" samples to improve duration accuracy 
-            adjustAmountOfSamples(nOut);
-
-            // finish
-            break;  
-        }
+        putSamples(buff, 128);
     }
 
+    adjustAmountOfSamples(numStillExpected);
+
     delete[] buff;
 
-    // Clear working buffers
-    pRateTransposer->clear();
+    // Clear input buffers
     pTDStretch->clearInput();
-    // yet leave the 'tempoChanger' output intouched as that's where the
+    // yet leave the output intouched as that's where the
     // flushed samples are!
 }
 
@@ -452,7 +410,7 @@ int SoundTouch::getSetting(int settingId) const
             return pRateTransposer->getAAFilter()->getLength();
 
         case SETTING_USE_QUICKSEEK :
-            return (uint)   pTDStretch->isQuickSeekEnabled();
+            return (uint)pTDStretch->isQuickSeekEnabled();
 
         case SETTING_SEQUENCE_MS:
             pTDStretch->getParameters(NULL, &temp, NULL, NULL);
@@ -466,13 +424,53 @@ int SoundTouch::getSetting(int settingId) const
             pTDStretch->getParameters(NULL, NULL, NULL, &temp);
             return temp;
 
-		case SETTING_NOMINAL_INPUT_SEQUENCE :
-			return pTDStretch->getInputSampleReq();
+        case SETTING_NOMINAL_INPUT_SEQUENCE :
+        {
+            int size = pTDStretch->getInputSampleReq();
 
-		case SETTING_NOMINAL_OUTPUT_SEQUENCE :
-			return pTDStretch->getOutputBatchSize();
+#ifndef SOUNDTOUCH_PREVENT_CLICK_AT_RATE_CROSSOVER
+            if (rate <= 1.0)
+            {
+                // transposing done before timestretch, which impacts latency
+                return (int)(size * rate + 0.5);
+            }
+#endif
+            return size;
+        }
 
-		default :
+        case SETTING_NOMINAL_OUTPUT_SEQUENCE :
+        {
+            int size = pTDStretch->getOutputBatchSize();
+
+            if (rate > 1.0)
+            {
+                // transposing done after timestretch, which impacts latency
+                return (int)(size / rate + 0.5);
+            }
+            return size;
+        }
+
+        case SETTING_INITIAL_LATENCY:
+        {
+            double latency = pTDStretch->getLatency();
+            int latency_tr = pRateTransposer->getLatency();
+
+#ifndef SOUNDTOUCH_PREVENT_CLICK_AT_RATE_CROSSOVER
+            if (rate <= 1.0)
+            {
+                // transposing done before timestretch, which impacts latency
+                latency = (latency + latency_tr) * rate;
+            }
+            else
+#endif
+            {
+                latency += (double)latency_tr / rate;
+            }
+
+            return (int)(latency + 0.5);
+        }
+
+        default :
             return 0;
     }
 }
@@ -482,12 +480,13 @@ int SoundTouch::getSetting(int settingId) const
 // buffers.
 void SoundTouch::clear()
 {
+    samplesExpectedOut = 0;
+    samplesOutput = 0;
     pRateTransposer->clear();
     pTDStretch->clear();
 }
 
 
-
 /// Returns number of samples currently unprocessed.
 uint SoundTouch::numUnprocessedSamples() const
 {
@@ -502,3 +501,38 @@ uint SoundTouch::numUnprocessedSamples() const
     }
     return 0;
 }
+
+
+/// Output samples from beginning of the sample buffer. Copies requested samples to
+/// output buffer and removes them from the sample buffer. If there are less than
+/// 'numsample' samples in the buffer, returns all that available.
+///
+/// \return Number of samples returned.
+uint SoundTouch::receiveSamples(SAMPLETYPE *output, uint maxSamples)
+{
+    uint ret = FIFOProcessor::receiveSamples(output, maxSamples);
+    samplesOutput += (long)ret;
+    return ret;
+}
+
+
+/// Adjusts book-keeping so that given number of samples are removed from beginning of the
+/// sample buffer without copying them anywhere.
+///
+/// Used to reduce the number of samples in the buffer when accessing the sample buffer directly
+/// with 'ptrBegin' function.
+uint SoundTouch::receiveSamples(uint maxSamples)
+{
+    uint ret = FIFOProcessor::receiveSamples(maxSamples);
+    samplesOutput += (long)ret;
+    return ret;
+}
+
+
+/// Get ratio between input and output audio durations, useful for calculating
+/// processed output duration: if you'll process a stream of N samples, then
+/// you can expect to get out N * getInputOutputSampleRatio() samples.
+double SoundTouch::getInputOutputSampleRatio()
+{
+    return 1.0 / (tempo * rate);
+}
diff --git a/media/libsoundtouch/src/SoundTouch.h b/media/libsoundtouch/src/SoundTouch.h
index 0581926b49..c9dd3c752a 100644
--- a/media/libsoundtouch/src/SoundTouch.h
+++ b/media/libsoundtouch/src/SoundTouch.h
@@ -41,13 +41,6 @@
 ///
 ////////////////////////////////////////////////////////////////////////////////
 //
-// Last changed  : $Date: 2015-05-18 15:28:41 +0000 (Mon, 18 May 2015) $
-// File revision : $Revision: 4 $
-//
-// $Id: SoundTouch.h 216 2015-05-18 15:28:41Z oparviai $
-//
-////////////////////////////////////////////////////////////////////////////////
-//
 // License :
 //
 //  SoundTouch audio processing library
@@ -79,10 +72,10 @@ namespace soundtouch
 {
 
 /// Soundtouch library version string
-#define SOUNDTOUCH_VERSION          "1.9.0"
+#define SOUNDTOUCH_VERSION          "2.2"
 
 /// SoundTouch library version id
-#define SOUNDTOUCH_VERSION_ID       (10900)
+#define SOUNDTOUCH_VERSION_ID       (20200)
 
 //
 // Available setting IDs for the 'setSetting' & 'get_setting' functions:
@@ -116,32 +109,63 @@ namespace soundtouch
 #define SETTING_OVERLAP_MS          5
 
 
-/// Call "getSetting" with this ID to query nominal average processing sequence
-/// size in samples. This value tells approcimate value how many input samples 
-/// SoundTouch needs to gather before it does DSP processing run for the sample batch.
+/// Call "getSetting" with this ID to query processing sequence size in samples.
+/// This value gives approximate value of how many input samples you'll need to
+/// feed into SoundTouch after initial buffering to get out a new batch of
+/// output samples.
+///
+/// This value does not include initial buffering at beginning of a new processing
+/// stream, use SETTING_INITIAL_LATENCY to get the initial buffering size.
 ///
 /// Notices: 
 /// - This is read-only parameter, i.e. setSetting ignores this parameter
-/// - Returned value is approximate average value, exact processing batch
-///   size may wary from time to time
-/// - This parameter value is not constant but may change depending on 
+/// - This parameter value is not constant but change depending on
 ///   tempo/pitch/rate/samplerate settings.
-#define SETTING_NOMINAL_INPUT_SEQUENCE		6
+#define SETTING_NOMINAL_INPUT_SEQUENCE      6
 
 
 /// Call "getSetting" with this ID to query nominal average processing output 
 /// size in samples. This value tells approcimate value how many output samples 
 /// SoundTouch outputs once it does DSP processing run for a batch of input samples.
-///	
+///
 /// Notices: 
 /// - This is read-only parameter, i.e. setSetting ignores this parameter
-/// - Returned value is approximate average value, exact processing batch
-///   size may wary from time to time
-/// - This parameter value is not constant but may change depending on 
+/// - This parameter value is not constant but change depending on
 ///   tempo/pitch/rate/samplerate settings.
-#define SETTING_NOMINAL_OUTPUT_SEQUENCE		7
+#define SETTING_NOMINAL_OUTPUT_SEQUENCE     7
 
-class EXPORT SoundTouch : public FIFOProcessor
+
+/// Call "getSetting" with this ID to query initial processing latency, i.e.
+/// approx. how many samples you'll need to enter to SoundTouch pipeline before
+/// you can expect to get first batch of ready output samples out.
+///
+/// After the first output batch, you can then expect to get approx.
+/// SETTING_NOMINAL_OUTPUT_SEQUENCE ready samples out for every
+/// SETTING_NOMINAL_INPUT_SEQUENCE samples that you enter into SoundTouch.
+///
+/// Example:
+///     processing with parameter -tempo=5
+///     => initial latency = 5509 samples
+///        input sequence  = 4167 samples
+///        output sequence = 3969 samples
+///
+/// Accordingly, you can expect to feed in approx. 5509 samples at beginning of
+/// the stream, and then you'll get out the first 3969 samples. After that, for
+/// every approx. 4167 samples that you'll put in, you'll receive again approx.
+/// 3969 samples out.
+///
+/// This also means that average latency during stream processing is
+/// INITIAL_LATENCY-OUTPUT_SEQUENCE/2, in the above example case 5509-3969/2
+/// = 3524 samples
+///
+/// Notices:
+/// - This is read-only parameter, i.e. setSetting ignores this parameter
+/// - This parameter value is not constant but change depending on
+///   tempo/pitch/rate/samplerate settings.
+#define SETTING_INITIAL_LATENCY             8
+
+
+class SOUNDTOUCH_API SoundTouch : public FIFOProcessor
 {
 private:
     /// Rate transposer class instance
@@ -151,17 +175,24 @@ private:
     class TDStretch *pTDStretch;
 
     /// Virtual pitch parameter. Effective rate & tempo are calculated from these parameters.
-    float virtualRate;
+    double virtualRate;
 
     /// Virtual pitch parameter. Effective rate & tempo are calculated from these parameters.
-    float virtualTempo;
+    double virtualTempo;
 
     /// Virtual pitch parameter. Effective rate & tempo are calculated from these parameters.
-    float virtualPitch;
+    double virtualPitch;
 
     /// Flag: Has sample rate been set?
     bool  bSrateSet;
 
+    /// Accumulator for how many samples in total will be expected as output vs. samples put in,
+    /// considering current processing settings.
+    double samplesExpectedOut;
+
+    /// Accumulator for how many samples in total have been read out from the processing so far
+    long   samplesOutput;
+
     /// Calculates effective rate & tempo valuescfrom 'virtualRate', 'virtualTempo' and 
     /// 'virtualPitch' parameters.
     void calcEffectiveRateAndTempo();
@@ -171,10 +202,10 @@ protected :
     uint  channels;
 
     /// Effective 'rate' value calculated from 'virtualRate', 'virtualTempo' and 'virtualPitch'
-    float rate;
+    double rate;
 
     /// Effective 'tempo' value calculated from 'virtualRate', 'virtualTempo' and 'virtualPitch'
-    float tempo;
+    double tempo;
 
 public:
     SoundTouch();
@@ -188,32 +219,32 @@ public:
 
     /// Sets new rate control value. Normal rate = 1.0, smaller values
     /// represent slower rate, larger faster rates.
-    void setRate(float newRate);
+    void setRate(double newRate);
 
     /// Sets new tempo control value. Normal tempo = 1.0, smaller values
     /// represent slower tempo, larger faster tempo.
-    void setTempo(float newTempo);
+    void setTempo(double newTempo);
 
     /// Sets new rate control value as a difference in percents compared
     /// to the original rate (-50 .. +100 %)
-    void setRateChange(float newRate);
+    void setRateChange(double newRate);
 
     /// Sets new tempo control value as a difference in percents compared
     /// to the original tempo (-50 .. +100 %)
-    void setTempoChange(float newTempo);
+    void setTempoChange(double newTempo);
 
     /// Sets new pitch control value. Original pitch = 1.0, smaller values
     /// represent lower pitches, larger values higher pitch.
-    void setPitch(float newPitch);
+    void setPitch(double newPitch);
 
     /// Sets pitch change in octaves compared to the original pitch  
     /// (-1.00 .. +1.00)
-    void setPitchOctaves(float newPitch);
+    void setPitchOctaves(double newPitch);
 
     /// Sets pitch change in semi-tones compared to the original pitch
     /// (-12 .. +12)
     void setPitchSemiTones(int newPitch);
-    void setPitchSemiTones(float newPitch);
+    void setPitchSemiTones(double newPitch);
 
     /// Sets the number of channels, 1 = mono, 2 = stereo
     void setChannels(uint numChannels);
@@ -221,6 +252,24 @@ public:
     /// Sets sample rate.
     void setSampleRate(uint srate);
 
+    /// Get ratio between input and output audio durations, useful for calculating
+    /// processed output duration: if you'll process a stream of N samples, then
+    /// you can expect to get out N * getInputOutputSampleRatio() samples.
+    ///
+    /// This ratio will give accurate target duration ratio for a full audio track,
+    /// given that the the whole track is processed with same processing parameters.
+    ///
+    /// If this ratio is applied to calculate intermediate offsets inside a processing
+    /// stream, then this ratio is approximate and can deviate +- some tens of milliseconds
+    /// from ideal offset, yet by end of the audio stream the duration ratio will become
+    /// exact.
+    ///
+    /// Example: if processing with parameters "-tempo=15 -pitch=-3", the function
+    /// will return value 0.8695652... Now, if processing an audio stream whose duration
+    /// is exactly one million audio samples, then you can expect the processed
+    /// output duration  be 0.869565 * 1000000 = 869565 samples.
+    double getInputOutputSampleRatio();
+
     /// Flushes the last samples from the processing pipeline to the output.
     /// Clears also the internal processing buffers.
     //
@@ -240,6 +289,23 @@ public:
                                                     ///< contains data for both channels.
             );
 
+    /// Output samples from beginning of the sample buffer. Copies requested samples to
+    /// output buffer and removes them from the sample buffer. If there are less than
+    /// 'numsample' samples in the buffer, returns all that available.
+    ///
+    /// \return Number of samples returned.
+    virtual uint receiveSamples(SAMPLETYPE *output, ///< Buffer where to copy output samples.
+        uint maxSamples                 ///< How many samples to receive at max.
+        );
+
+    /// Adjusts book-keeping so that given number of samples are removed from beginning of the
+    /// sample buffer without copying them anywhere.
+    ///
+    /// Used to reduce the number of samples in the buffer when accessing the sample buffer directly
+    /// with 'ptrBegin' function.
+    virtual uint receiveSamples(uint maxSamples   ///< Remove this many samples from the beginning of pipe.
+        );
+
     /// Clears all the samples in the object's output and internal processing
     /// buffers.
     virtual void clear();
@@ -247,7 +313,7 @@ public:
     /// Changes a setting controlling the processing system behaviour. See the
     /// 'SETTING_...' defines for available setting ID's.
     /// 
-    /// \return 'true' if the setting was succesfully changed
+    /// \return 'true' if the setting was successfully changed
     bool setSetting(int settingId,   ///< Setting ID number. see SETTING_... defines.
                     int value        ///< New setting value.
                     );
@@ -262,6 +328,11 @@ public:
     /// Returns number of samples currently unprocessed.
     virtual uint numUnprocessedSamples() const;
 
+    /// Return number of channels
+    uint numChannels() const
+    {
+        return channels;
+    }
 
     /// Other handy functions that are implemented in the ancestor classes (see
     /// classes 'FIFOProcessor' and 'FIFOSamplePipe')
diff --git a/media/libsoundtouch/src/SoundTouchFactory.cpp b/media/libsoundtouch/src/SoundTouchFactory.cpp
index 8cfc8ba252..b4b1308a13 100644
--- a/media/libsoundtouch/src/SoundTouchFactory.cpp
+++ b/media/libsoundtouch/src/SoundTouchFactory.cpp
@@ -7,14 +7,14 @@
 namespace soundtouch
 {
 
-EXPORT
+SOUNDTOUCH_API
 soundtouch::SoundTouch*
 createSoundTouchObj()
 {
   return new soundtouch::SoundTouch();
 }
 
-EXPORT
+SOUNDTOUCH_API
 void
 destroySoundTouchObj(soundtouch::SoundTouch* aObj)
 {
diff --git a/media/libsoundtouch/src/SoundTouchFactory.h b/media/libsoundtouch/src/SoundTouchFactory.h
index 693c012f4d..65787fba06 100644
--- a/media/libsoundtouch/src/SoundTouchFactory.h
+++ b/media/libsoundtouch/src/SoundTouchFactory.h
@@ -10,11 +10,11 @@
 
 namespace soundtouch
 {
-EXPORT
+SOUNDTOUCH_API
 soundtouch::SoundTouch*
 createSoundTouchObj();
 
-EXPORT
+SOUNDTOUCH_API
 void
 destroySoundTouchObj(soundtouch::SoundTouch* aObj);
 }
diff --git a/media/libsoundtouch/src/TDStretch.cpp b/media/libsoundtouch/src/TDStretch.cpp
index 81bde22f01..ab0e82df8f 100644
--- a/media/libsoundtouch/src/TDStretch.cpp
+++ b/media/libsoundtouch/src/TDStretch.cpp
@@ -1,11 +1,17 @@
-////////////////////////////////////////////////////////////////////////////////
-/// 
-/// Sampled sound tempo changer/time stretch algorithm. Changes the sound tempo 
-/// while maintaining the original pitch by using a time domain WSOLA-like 
+///////////////////////////////////////////////////////////////////////////////
+///
+/// Sampled sound tempo changer/time stretch algorithm. Changes the sound tempo
+/// while maintaining the original pitch by using a time domain WSOLA-like
 /// method with several performance-increasing tweaks.
 ///
-/// Note : MMX optimized functions reside in a separate, platform-specific 
-/// file, e.g. 'mmx_win.cpp' or 'mmx_gcc.cpp'
+/// Notes : MMX optimized functions reside in a separate, platform-specific
+/// file, e.g. 'mmx_win.cpp' or 'mmx_gcc.cpp'.
+///
+/// This source file contains OpenMP optimizations that allow speeding up the
+/// corss-correlation algorithm by executing it in several threads / CPU cores
+/// in parallel. See the following article link for more detailed discussion
+/// about SoundTouch OpenMP optimizations:
+/// http://www.softwarecoven.com/parallel-computing-in-embedded-mobile-devices
 ///
 /// Author        : Copyright (c) Olli Parviainen
 /// Author e-mail : oparviai 'at' iki.fi
@@ -13,13 +19,6 @@
 ///
 ////////////////////////////////////////////////////////////////////////////////
 //
-// Last changed  : $Date: 2015-02-22 15:07:12 +0000 (Sun, 22 Feb 2015) $
-// File revision : $Revision: 1.12 $
-//
-// $Id: TDStretch.cpp 205 2015-02-22 15:07:12Z oparviai $
-//
-////////////////////////////////////////////////////////////////////////////////
-//
 // License :
 //
 //  SoundTouch audio processing library
@@ -55,7 +54,6 @@ using namespace soundtouch;
 
 #define max(x, y) (((x) > (y)) ? (x) : (y))
 
-
 /*****************************************************************************
  *
  * Constant definitions
@@ -63,7 +61,7 @@ using namespace soundtouch;
  *****************************************************************************/
 
 // Table for the hierarchical mixing position seeking algorithm
-static const short _scanOffsets[5][24]={
+const short _scanOffsets[5][24]={
     { 124,  186,  248,  310,  372,  434,  496,  558,  620,  682,  744, 806,
       868,  930,  992, 1054, 1116, 1178, 1240, 1302, 1364, 1426, 1488,   0},
     {-100,  -75,  -50,  -25,   25,   50,   75,  100,    0,    0,    0,   0,
@@ -94,9 +92,6 @@ TDStretch::TDStretch() : FIFOProcessor(&outputBuffer)
     bAutoSeqSetting = true;
     bAutoSeekSetting = true;
 
-//    outDebt = 0;
-    skipFract = 0;
-
     tempo = 1.0f;
     setParameters(44100, DEFAULT_SEQUENCE_MS, DEFAULT_SEEKWINDOW_MS, DEFAULT_OVERLAP_MS);
     setTempo(1.0f);
@@ -126,8 +121,13 @@ void TDStretch::setParameters(int aSampleRate, int aSequenceMS,
                               int aSeekWindowMS, int aOverlapMS)
 {
     // accept only positive parameter values - if zero or negative, use old values instead
-    if (aSampleRate > 0)   this->sampleRate = aSampleRate;
-    if (aOverlapMS > 0)    this->overlapMs = aOverlapMS;
+    if (aSampleRate > 0)
+    {
+        if (aSampleRate > 192000) ST_THROW_RT_ERROR("Error: Excessive samplerate");
+        this->sampleRate = aSampleRate;
+    }
+
+    if (aOverlapMS > 0) this->overlapMs = aOverlapMS;
 
     if (aSequenceMS > 0)
     {
@@ -197,7 +197,7 @@ void TDStretch::overlapMono(SAMPLETYPE *pOutput, const SAMPLETYPE *pInput) const
     m1 = (SAMPLETYPE)0;
     m2 = (SAMPLETYPE)overlapLength;
 
-    for (i = 0; i < overlapLength ; i ++) 
+    for (i = 0; i < overlapLength ; i ++)
     {
         pOutput[i] = (pInput[i] * m1 + pMidBuffer[i] * m2 ) / overlapLength;
         m1 += 1;
@@ -217,6 +217,10 @@ void TDStretch::clearInput()
 {
     inputBuffer.clear();
     clearMidBuffer();
+    isBeginning = true;
+    maxnorm = 0;
+    maxnormf = 1e8;
+    skipFract = 0;
 }
 
 
@@ -250,7 +254,7 @@ int TDStretch::seekBestOverlapPosition(const SAMPLETYPE *refPos)
     if (bQuickSeek) 
     {
         return seekBestOverlapPositionQuick(refPos);
-    } 
+    }
     else 
     {
         return seekBestOverlapPositionFull(refPos);
@@ -282,7 +286,6 @@ inline void TDStretch::overlap(SAMPLETYPE *pOutput, const SAMPLETYPE *pInput, ui
 }
 
 
-
 // Seeks for the optimal overlap-mixing position. The 'stereo' version of the
 // routine
 //
@@ -296,21 +299,23 @@ int TDStretch::seekBestOverlapPositionFull(const SAMPLETYPE *refPos)
     int i;
     double norm;
 
-    bestCorr = FLT_MIN;
+    bestCorr = -FLT_MAX;
     bestOffs = 0;
 
     // Scans for the best correlation value by testing each possible position
     // over the permitted range.
     bestCorr = calcCrossCorr(refPos, pMidBuffer, norm);
+    bestCorr = (bestCorr + 0.1) * 0.75;
 
     #pragma omp parallel for
-    for (i = 1; i < seekLength; i ++) 
+    for (i = 1; i < seekLength; i ++)
     {
         double corr;
         // Calculates correlation value for the mixing position corresponding to 'i'
-#ifdef _OPENMP
+#if defined(_OPENMP) || defined(ST_SIMD_AVOID_UNALIGNED)
         // in parallel OpenMP mode, can't use norm accumulator version as parallel executor won't
         // iterate the loop in sequential order
+        // in SIMD mode, avoid accumulator version to allow avoiding unaligned positions
         corr = calcCrossCorr(refPos + channels * i, pMidBuffer, norm);
 #else
         // In non-parallel version call "calcCrossCorrAccumulate" that is otherwise same
@@ -336,6 +341,11 @@ int TDStretch::seekBestOverlapPositionFull(const SAMPLETYPE *refPos)
             }
         }
     }
+
+#ifdef SOUNDTOUCH_INTEGER_SAMPLES
+    adaptNormalizer();
+#endif
+
     // clear cross correlation routine state if necessary (is so e.g. in MMX routines).
     clearCrossCorrState();
 
@@ -343,64 +353,157 @@ int TDStretch::seekBestOverlapPositionFull(const SAMPLETYPE *refPos)
 }
 
 
-// Seeks for the optimal overlap-mixing position. The 'stereo' version of the
-// routine
+// Quick seek algorithm for improved runtime-performance: First roughly scans through the
+// correlation area, and then scan surroundings of two best preliminary correlation candidates
+// with improved precision
 //
-// The best position is determined as the position where the two overlapped
-// sample sequences are 'most alike', in terms of the highest cross-correlation
-// value over the overlapping period
-int TDStretch::seekBestOverlapPositionQuick(const SAMPLETYPE *refPos) 
+// Based on testing:
+// - This algorithm gives on average 99% as good match as the full algorithm
+// - this quick seek algorithm finds the best match on ~90% of cases
+// - on those 10% of cases when this algorithm doesn't find best match,
+//   it still finds on average ~90% match vs. the best possible match
+int TDStretch::seekBestOverlapPositionQuick(const SAMPLETYPE *refPos)
 {
-    int j;
+#define _MIN(a, b)   (((a) < (b)) ? (a) : (b))
+#define SCANSTEP    16
+#define SCANWIND    8
+
     int bestOffs;
-    double bestCorr, corr;
-    int scanCount, corrOffset, tempOffset;
+    int i;
+    int bestOffs2;
+    float bestCorr, corr;
+    float bestCorr2;
+    double norm;
 
-    bestCorr = FLT_MIN;
-    bestOffs = _scanOffsets[0][0];
-    corrOffset = 0;
-    tempOffset = 0;
+    // note: 'float' types used in this function in case that the platform would need to use software-fp
 
-    // Scans for the best correlation value using four-pass hierarchical search.
+    bestCorr =
+    bestCorr2 = -FLT_MAX;
+    bestOffs =
+    bestOffs2 = SCANWIND;
+
+    // Scans for the best correlation value by testing each possible position
+    // over the permitted range. Look for two best matches on the first pass to
+    // increase possibility of ideal match.
     //
-    // The look-up table 'scans' has hierarchical position adjusting steps.
-    // In first pass the routine searhes for the highest correlation with 
-    // relatively coarse steps, then rescans the neighbourhood of the highest
-    // correlation with better resolution and so on.
-    for (scanCount = 0;scanCount < 4; scanCount ++) 
+    // Begin from "SCANSTEP" instead of SCANWIND to make the calculation
+    // catch the 'middlepoint' of seekLength vector as that's the a-priori
+    // expected best match position
+    //
+    // Roughly:
+    // - 15% of cases find best result directly on the first round,
+    // - 75% cases find better match on 2nd round around the best match from 1st round
+    // - 10% cases find better match on 2nd round around the 2nd-best-match from 1st round
+    for (i = SCANSTEP; i < seekLength - SCANWIND - 1; i += SCANSTEP)
     {
-        j = 0;
-        while (_scanOffsets[scanCount][j]) 
+        // Calculates correlation value for the mixing position corresponding
+        // to 'i'
+        corr = (float)calcCrossCorr(refPos + channels*i, pMidBuffer, norm);
+        // heuristic rule to slightly favour values close to mid of the seek range
+        float tmp = (float)(2 * i - seekLength - 1) / (float)seekLength;
+        corr = ((corr + 0.1f) * (1.0f - 0.25f * tmp * tmp));
+
+        // Checks for the highest correlation value
+        if (corr > bestCorr)
         {
-            double norm;
-            tempOffset = corrOffset + _scanOffsets[scanCount][j];
-            if (tempOffset >= seekLength) break;
-
-            // Calculates correlation value for the mixing position corresponding
-            // to 'tempOffset'
-            corr = (double)calcCrossCorr(refPos + channels * tempOffset, pMidBuffer, norm);
-            // heuristic rule to slightly favour values close to mid of the range
-            double tmp = (double)(2 * tempOffset - seekLength) / seekLength;
-            corr = ((corr + 0.1) * (1.0 - 0.25 * tmp * tmp));
-
-            // Checks for the highest correlation value
-            if (corr > bestCorr) 
-            {
-                bestCorr = corr;
-                bestOffs = tempOffset;
-            }
-            j ++;
+            // found new best match. keep the previous best as 2nd best match
+            bestCorr2 = bestCorr;
+            bestOffs2 = bestOffs;
+            bestCorr = corr;
+            bestOffs = i;
+        }
+        else if (corr > bestCorr2)
+        {
+            // not new best, but still new 2nd best match
+            bestCorr2 = corr;
+            bestOffs2 = i;
         }
-        corrOffset = bestOffs;
     }
+
+    // Scans surroundings of the found best match with small stepping
+    int end = _MIN(bestOffs + SCANWIND + 1, seekLength);
+    for (i = bestOffs - SCANWIND; i < end; i++)
+    {
+        if (i == bestOffs) continue;    // this offset already calculated, thus skip
+
+        // Calculates correlation value for the mixing position corresponding
+        // to 'i'
+        corr = (float)calcCrossCorr(refPos + channels*i, pMidBuffer, norm);
+        // heuristic rule to slightly favour values close to mid of the range
+        float tmp = (float)(2 * i - seekLength - 1) / (float)seekLength;
+        corr = ((corr + 0.1f) * (1.0f - 0.25f * tmp * tmp));
+
+        // Checks for the highest correlation value
+        if (corr > bestCorr)
+        {
+            bestCorr = corr;
+            bestOffs = i;
+        }
+    }
+
+    // Scans surroundings of the 2nd best match with small stepping
+    end = _MIN(bestOffs2 + SCANWIND + 1, seekLength);
+    for (i = bestOffs2 - SCANWIND; i < end; i++)
+    {
+        if (i == bestOffs2) continue;    // this offset already calculated, thus skip
+
+        // Calculates correlation value for the mixing position corresponding
+        // to 'i'
+        corr = (float)calcCrossCorr(refPos + channels*i, pMidBuffer, norm);
+        // heuristic rule to slightly favour values close to mid of the range
+        float tmp = (float)(2 * i - seekLength - 1) / (float)seekLength;
+        corr = ((corr + 0.1f) * (1.0f - 0.25f * tmp * tmp));
+
+        // Checks for the highest correlation value
+        if (corr > bestCorr)
+        {
+            bestCorr = corr;
+            bestOffs = i;
+        }
+    }
+
     // clear cross correlation routine state if necessary (is so e.g. in MMX routines).
     clearCrossCorrState();
 
+#ifdef SOUNDTOUCH_INTEGER_SAMPLES
+    adaptNormalizer();
+#endif
+
     return bestOffs;
 }
 
 
 
+
+/// For integer algorithm: adapt normalization factor divider with music so that
+/// it'll not be pessimistically restrictive that can degrade quality on quieter sections
+/// yet won't cause integer overflows either
+void TDStretch::adaptNormalizer()
+{
+    // Do not adapt normalizer over too silent sequences to avoid averaging filter depleting to
+    // too low values during pauses in music
+    if ((maxnorm > 1000) || (maxnormf > 40000000))
+    {
+        //norm averaging filter
+        maxnormf = 0.9f * maxnormf + 0.1f * (float)maxnorm;
+
+        if ((maxnorm > 800000000) && (overlapDividerBitsNorm < 16))
+        {
+            // large values, so increase divider
+            overlapDividerBitsNorm++;
+            if (maxnorm > 1600000000) overlapDividerBitsNorm++; // extra large value => extra increase
+        }
+        else if ((maxnormf < 1000000) && (overlapDividerBitsNorm > 0))
+        {
+            // extra small values, decrease divider
+            overlapDividerBitsNorm--;
+        }
+    }
+
+    maxnorm = 0;
+}
+
+
 /// clear cross correlation routine state if necessary 
 void TDStretch::clearCrossCorrState()
 {
@@ -412,18 +515,18 @@ void TDStretch::clearCrossCorrState()
 void TDStretch::calcSeqParameters()
 {
     // Adjust tempo param according to tempo, so that variating processing sequence length is used
-    // at varius tempo settings, between the given low...top limits
+    // at various tempo settings, between the given low...top limits
     #define AUTOSEQ_TEMPO_LOW   0.5     // auto setting low tempo range (-50%)
     #define AUTOSEQ_TEMPO_TOP   2.0     // auto setting top tempo range (+100%)
 
     // sequence-ms setting values at above low & top tempo
-    #define AUTOSEQ_AT_MIN      125.0
-    #define AUTOSEQ_AT_MAX      50.0
+    #define AUTOSEQ_AT_MIN      90.0
+    #define AUTOSEQ_AT_MAX      40.0
     #define AUTOSEQ_K           ((AUTOSEQ_AT_MAX - AUTOSEQ_AT_MIN) / (AUTOSEQ_TEMPO_TOP - AUTOSEQ_TEMPO_LOW))
     #define AUTOSEQ_C           (AUTOSEQ_AT_MIN - (AUTOSEQ_K) * (AUTOSEQ_TEMPO_LOW))
 
-    // seek-window-ms setting values at above low & top tempo
-    #define AUTOSEEK_AT_MIN     25.0
+    // seek-window-ms setting values at above low & top tempoq
+    #define AUTOSEEK_AT_MIN     20.0
     #define AUTOSEEK_AT_MAX     15.0
     #define AUTOSEEK_K          ((AUTOSEEK_AT_MAX - AUTOSEEK_AT_MIN) / (AUTOSEQ_TEMPO_TOP - AUTOSEQ_TEMPO_LOW))
     #define AUTOSEEK_C          (AUTOSEEK_AT_MIN - (AUTOSEEK_K) * (AUTOSEQ_TEMPO_LOW))
@@ -459,7 +562,7 @@ void TDStretch::calcSeqParameters()
 
 // Sets new target tempo. Normal tempo = 'SCALE', smaller values represent slower 
 // tempo, larger faster tempo.
-void TDStretch::setTempo(float newTempo)
+void TDStretch::setTempo(double newTempo)
 {
     int intskip;
 
@@ -470,7 +573,7 @@ void TDStretch::setTempo(float newTempo)
 
     // Calculate ideal skip length (according to tempo value) 
     nominalSkip = tempo * (seekWindowLength - overlapLength);
-    intskip = (int)(nominalSkip + 0.5f);
+    intskip = (int)(nominalSkip + 0.5);
 
     // Calculate how many samples are needed in the 'inputBuffer' to 
     // process another batch of samples
@@ -483,9 +586,8 @@ void TDStretch::setTempo(float newTempo)
 // Sets the number of channels, 1 = mono, 2 = stereo
 void TDStretch::setChannels(int numChannels)
 {
-    assert(numChannels > 0);
-    if (channels == numChannels) return;
-//    assert(numChannels == 1 || numChannels == 2);
+    if (!verifyNumberOfChannels(numChannels) ||
+        (channels == numChannels)) return;
 
     channels = numChannels;
     inputBuffer.setChannels(channels);
@@ -534,7 +636,8 @@ void TDStretch::processNominalTempo()
 // the result into 'outputBuffer'
 void TDStretch::processSamples()
 {
-    int ovlSkip, offset;
+    int ovlSkip;
+    int offset = 0;
     int temp;
 
     /* Removed this small optimization - can introduce a click to sound when tempo setting
@@ -551,35 +654,62 @@ void TDStretch::processSamples()
     // to form a processing frame.
     while ((int)inputBuffer.numSamples() >= sampleReq) 
     {
-        // If tempo differs from the normal ('SCALE'), scan for the best overlapping
-        // position
-        offset = seekBestOverlapPosition(inputBuffer.ptrBegin());
+        if (isBeginning == false)
+        {
+            // apart from the very beginning of the track,
+            // scan for the best overlapping position & do overlap-add
+            offset = seekBestOverlapPosition(inputBuffer.ptrBegin());
 
-        // Mix the samples in the 'inputBuffer' at position of 'offset' with the 
-        // samples in 'midBuffer' using sliding overlapping
-        // ... first partially overlap with the end of the previous sequence
-        // (that's in 'midBuffer')
-        overlap(outputBuffer.ptrEnd((uint)overlapLength), inputBuffer.ptrBegin(), (uint)offset);
-        outputBuffer.putSamples((uint)overlapLength);
+            // Mix the samples in the 'inputBuffer' at position of 'offset' with the
+            // samples in 'midBuffer' using sliding overlapping
+            // ... first partially overlap with the end of the previous sequence
+            // (that's in 'midBuffer')
+            overlap(outputBuffer.ptrEnd((uint)overlapLength), inputBuffer.ptrBegin(), (uint)offset);
+            outputBuffer.putSamples((uint)overlapLength);
+            offset += overlapLength;
+        }
+        else
+        {
+            // Adjust processing offset at beginning of track by not perform initial overlapping
+            // and compensating that in the 'input buffer skip' calculation
+            isBeginning = false;
+            int skip = (int)(tempo * overlapLength + 0.5 * seekLength + 0.5);
+
+            #ifdef ST_SIMD_AVOID_UNALIGNED
+            // in SIMD mode, round the skip amount to value corresponding to aligned memory address
+            if (channels == 1)
+            {
+                skip &= -4;
+            }
+            else if (channels == 2)
+            {
+                skip &= -2;
+            }
+            #endif
+            skipFract -= skip;
+            if (skipFract <= -nominalSkip)
+            {
+                skipFract = -nominalSkip;
+            }
+        }
 
         // ... then copy sequence samples from 'inputBuffer' to output:
 
-        // length of sequence
-        temp = (seekWindowLength - 2 * overlapLength);
-
         // crosscheck that we don't have buffer overflow...
-        if ((int)inputBuffer.numSamples() < (offset + temp + overlapLength * 2))
+        if ((int)inputBuffer.numSamples() < (offset + seekWindowLength - overlapLength))
         {
             continue;    // just in case, shouldn't really happen
         }
 
-        outputBuffer.putSamples(inputBuffer.ptrBegin() + channels * (offset + overlapLength), (uint)temp);
+        // length of sequence
+        temp = (seekWindowLength - 2 * overlapLength);
+        outputBuffer.putSamples(inputBuffer.ptrBegin() + channels * offset, (uint)temp);
 
         // Copies the end of the current sequence from 'inputBuffer' to 
         // 'midBuffer' for being mixed with the beginning of the next 
         // processing sequence and so on
-        assert((offset + temp + overlapLength * 2) <= (int)inputBuffer.numSamples());
-        memcpy(pMidBuffer, inputBuffer.ptrBegin() + channels * (offset + temp + overlapLength), 
+        assert((offset + temp + overlapLength) <= (int)inputBuffer.numSamples());
+        memcpy(pMidBuffer, inputBuffer.ptrBegin() + channels * (offset + temp),
             channels * sizeof(SAMPLETYPE) * overlapLength);
 
         // Remove the processed samples from the input buffer. Update
@@ -675,7 +805,7 @@ TDStretch * TDStretch::newInstance()
 
 //////////////////////////////////////////////////////////////////////////////
 //
-// Integer arithmetics specific algorithm implementations.
+// Integer arithmetic specific algorithm implementations.
 //
 //////////////////////////////////////////////////////////////////////////////
 
@@ -689,7 +819,7 @@ void TDStretch::overlapStereo(short *poutput, const short *input) const
     short temp;
     int cnt2;
 
-    for (i = 0; i < overlapLength ; i ++) 
+    for (i = 0; i < overlapLength ; i ++)
     {
         temp = (short)(overlapLength - i);
         cnt2 = 2 * i;
@@ -701,21 +831,19 @@ void TDStretch::overlapStereo(short *poutput, const short *input) const
 
 // Overlaps samples in 'midBuffer' with the samples in 'input'. The 'Multi'
 // version of the routine.
-void TDStretch::overlapMulti(SAMPLETYPE *poutput, const SAMPLETYPE *input) const
+void TDStretch::overlapMulti(short *poutput, const short *input) const
 {
-    SAMPLETYPE m1=(SAMPLETYPE)0;
-    SAMPLETYPE m2;
-    int i=0;
+    short m1;
+    int i = 0;
 
-    for (m2 = (SAMPLETYPE)overlapLength; m2; m2 --)
+    for (m1 = 0; m1 < overlapLength; m1 ++)
     {
+        short m2 = (short)(overlapLength - m1);
         for (int c = 0; c < channels; c ++)
         {
             poutput[i] = (input[i] * m1 + pMidBuffer[i] * m2)  / overlapLength;
             i++;
         }
-
-        m1++;
     }
 }
 
@@ -738,13 +866,15 @@ void TDStretch::calculateOverlapLength(int aoverlapMs)
     // calculate overlap length so that it's power of 2 - thus it's easy to do
     // integer division by right-shifting. Term "-1" at end is to account for 
     // the extra most significatnt bit left unused in result by signed multiplication 
-    overlapDividerBits = _getClosest2Power((sampleRate * aoverlapMs) / 1000.0) - 1;
-    if (overlapDividerBits > 9) overlapDividerBits = 9;
-    if (overlapDividerBits < 3) overlapDividerBits = 3;
-    newOvl = (int)pow(2.0, (int)overlapDividerBits + 1);    // +1 => account for -1 above
+    overlapDividerBitsPure = _getClosest2Power((sampleRate * aoverlapMs) / 1000.0) - 1;
+    if (overlapDividerBitsPure > 9) overlapDividerBitsPure = 9;
+    if (overlapDividerBitsPure < 3) overlapDividerBitsPure = 3;
+    newOvl = (int)pow(2.0, (int)overlapDividerBitsPure + 1);    // +1 => account for -1 above
 
     acceptNewOverlapLength(newOvl);
 
+    overlapDividerBitsNorm = overlapDividerBitsPure;
+
     // calculate sloping divider so that crosscorrelation operation won't 
     // overflow 32-bit register. Max. sum of the crosscorrelation sum without 
     // divider would be 2^30*(N^3-N)/3, where N = overlap length
@@ -752,28 +882,40 @@ void TDStretch::calculateOverlapLength(int aoverlapMs)
 }
 
 
-double TDStretch::calcCrossCorr(const short *mixingPos, const short *compare, double &norm) const
+double TDStretch::calcCrossCorr(const short *mixingPos, const short *compare, double &norm)
 {
     long corr;
-    long lnorm;
+    unsigned long lnorm;
     int i;
 
+    #ifdef ST_SIMD_AVOID_UNALIGNED
+        // in SIMD mode skip 'mixingPos' positions that aren't aligned to 16-byte boundary
+        if (((ulongptr)mixingPos) & 15) return -1e50;
+    #endif
+
+    // hint compiler autovectorization that loop length is divisible by 8
+    int ilength = (channels * overlapLength) & -8;
+
     corr = lnorm = 0;
-    // Same routine for stereo and mono. For stereo, unroll loop for better
-    // efficiency and gives slightly better resolution against rounding. 
-    // For mono it same routine, just  unrolls loop by factor of 4
-    for (i = 0; i < channels * overlapLength; i += 4) 
+    // Same routine for stereo and mono
+    for (i = 0; i < ilength; i += 2)
     {
         corr += (mixingPos[i] * compare[i] + 
-                 mixingPos[i + 1] * compare[i + 1]) >> overlapDividerBits;  // notice: do intermediate division here to avoid integer overflow
-        corr += (mixingPos[i + 2] * compare[i + 2] + 
-                 mixingPos[i + 3] * compare[i + 3]) >> overlapDividerBits;
+                 mixingPos[i + 1] * compare[i + 1]) >> overlapDividerBitsNorm;
         lnorm += (mixingPos[i] * mixingPos[i] + 
-                  mixingPos[i + 1] * mixingPos[i + 1]) >> overlapDividerBits; // notice: do intermediate division here to avoid integer overflow
-        lnorm += (mixingPos[i + 2] * mixingPos[i + 2] + 
-                  mixingPos[i + 3] * mixingPos[i + 3]) >> overlapDividerBits;
+                  mixingPos[i + 1] * mixingPos[i + 1]) >> overlapDividerBitsNorm;
+        // do intermediate scalings to avoid integer overflow
     }
 
+    if (lnorm > maxnorm)
+    {
+        // modify 'maxnorm' inside critical section to avoid multi-access conflict if in OpenMP mode
+        #pragma omp critical
+        if (lnorm > maxnorm)
+        {
+            maxnorm = lnorm;
+        }
+    }
     // Normalize result by dividing by sqrt(norm) - this step is easiest 
     // done using floating point operation
     norm = (double)lnorm;
@@ -782,40 +924,44 @@ double TDStretch::calcCrossCorr(const short *mixingPos, const short *compare, do
 
 
 /// Update cross-correlation by accumulating "norm" coefficient by previously calculated value
-double TDStretch::calcCrossCorrAccumulate(const short *mixingPos, const short *compare, double &norm) const
+double TDStretch::calcCrossCorrAccumulate(const short *mixingPos, const short *compare, double &norm)
 {
     long corr;
     long lnorm;
     int i;
 
+    // hint compiler autovectorization that loop length is divisible by 8
+    int ilength = (channels * overlapLength) & -8;
+
     // cancel first normalizer tap from previous round
     lnorm = 0;
     for (i = 1; i <= channels; i ++)
     {
-        lnorm -= (mixingPos[-i] * mixingPos[-i]) >> overlapDividerBits;
+        lnorm -= (mixingPos[-i] * mixingPos[-i]) >> overlapDividerBitsNorm;
     }
 
     corr = 0;
-    // Same routine for stereo and mono. For stereo, unroll loop for better
-    // efficiency and gives slightly better resolution against rounding. 
-    // For mono it same routine, just  unrolls loop by factor of 4
-    for (i = 0; i < channels * overlapLength; i += 4) 
+    // Same routine for stereo and mono.
+    for (i = 0; i < ilength; i += 2)
     {
-        corr += (mixingPos[i] * compare[i] + 
-                 mixingPos[i + 1] * compare[i + 1]) >> overlapDividerBits;  // notice: do intermediate division here to avoid integer overflow
-        corr += (mixingPos[i + 2] * compare[i + 2] + 
-                 mixingPos[i + 3] * compare[i + 3]) >> overlapDividerBits;
+        corr += (mixingPos[i] * compare[i] +
+                 mixingPos[i + 1] * compare[i + 1]) >> overlapDividerBitsNorm;
     }
 
     // update normalizer with last samples of this round
     for (int j = 0; j < channels; j ++)
     {
         i --;
-        lnorm += (mixingPos[i] * mixingPos[i]) >> overlapDividerBits;
+        lnorm += (mixingPos[i] * mixingPos[i]) >> overlapDividerBitsNorm;
     }
-    norm += (double)lnorm;
 
-    // Normalize result by dividing by sqrt(norm) - this step is easiest 
+    norm += (double)lnorm;
+    if (norm > maxnorm)
+    {
+        maxnorm = (unsigned long)norm;
+    }
+
+    // Normalize result by dividing by sqrt(norm) - this step is easiest
     // done using floating point operation
     return (double)corr / sqrt((norm < 1e-9) ? 1.0 : norm);
 }
@@ -824,7 +970,7 @@ double TDStretch::calcCrossCorrAccumulate(const short *mixingPos, const short *c
 
 //////////////////////////////////////////////////////////////////////////////
 //
-// Floating point arithmetics specific algorithm implementations.
+// Floating point arithmetic specific algorithm implementations.
 //
 
 #ifdef SOUNDTOUCH_FLOAT_SAMPLES
@@ -898,29 +1044,26 @@ void TDStretch::calculateOverlapLength(int overlapInMsec)
 
 
 /// Calculate cross-correlation
-double TDStretch::calcCrossCorr(const float *mixingPos, const float *compare, double &anorm) const
+double TDStretch::calcCrossCorr(const float *mixingPos, const float *compare, double &anorm)
 {
-    double corr;
-    double norm;
+    float corr;
+    float norm;
     int i;
 
+    #ifdef ST_SIMD_AVOID_UNALIGNED
+        // in SIMD mode skip 'mixingPos' positions that aren't aligned to 16-byte boundary
+        if (((ulongptr)mixingPos) & 15) return -1e50;
+    #endif
+
+    // hint compiler autovectorization that loop length is divisible by 8
+    int ilength = (channels * overlapLength) & -8;
+
     corr = norm = 0;
-    // Same routine for stereo and mono. For Stereo, unroll by factor of 2.
-    // For mono it's same routine yet unrollsd by factor of 4.
-    for (i = 0; i < channels * overlapLength; i += 4) 
+    // Same routine for stereo and mono
+    for (i = 0; i < ilength; i ++)
     {
-        corr += mixingPos[i] * compare[i] +
-                mixingPos[i + 1] * compare[i + 1];
-
-        norm += mixingPos[i] * mixingPos[i] + 
-                mixingPos[i + 1] * mixingPos[i + 1];
-
-        // unroll the loop for better CPU efficiency:
-        corr += mixingPos[i + 2] * compare[i + 2] +
-                mixingPos[i + 3] * compare[i + 3];
-
-        norm += mixingPos[i + 2] * mixingPos[i + 2] +
-                mixingPos[i + 3] * mixingPos[i + 3];
+        corr += mixingPos[i] * compare[i];
+        norm += mixingPos[i] * mixingPos[i];
     }
 
     anorm = norm;
@@ -929,9 +1072,9 @@ double TDStretch::calcCrossCorr(const float *mixingPos, const float *compare, do
 
 
 /// Update cross-correlation by accumulating "norm" coefficient by previously calculated value
-double TDStretch::calcCrossCorrAccumulate(const float *mixingPos, const float *compare, double &norm) const
+double TDStretch::calcCrossCorrAccumulate(const float *mixingPos, const float *compare, double &norm)
 {
-    double corr;
+    float corr;
     int i;
 
     corr = 0;
@@ -942,14 +1085,13 @@ double TDStretch::calcCrossCorrAccumulate(const float *mixingPos, const float *c
         norm -= mixingPos[-i] * mixingPos[-i];
     }
 
-    // Same routine for stereo and mono. For Stereo, unroll by factor of 2.
-    // For mono it's same routine yet unrollsd by factor of 4.
-    for (i = 0; i < channels * overlapLength; i += 4) 
+    // hint compiler autovectorization that loop length is divisible by 8
+    int ilength = (channels * overlapLength) & -8;
+
+    // Same routine for stereo and mono
+    for (i = 0; i < ilength; i ++)
     {
-        corr += mixingPos[i] * compare[i] +
-                mixingPos[i + 1] * compare[i + 1] +
-                mixingPos[i + 2] * compare[i + 2] +
-                mixingPos[i + 3] * compare[i + 3];
+        corr += mixingPos[i] * compare[i];
     }
 
     // update normalizer with last samples of this round
diff --git a/media/libsoundtouch/src/TDStretch.h b/media/libsoundtouch/src/TDStretch.h
index b390736913..3ef79c7cdf 100644
--- a/media/libsoundtouch/src/TDStretch.h
+++ b/media/libsoundtouch/src/TDStretch.h
@@ -13,13 +13,6 @@
 ///
 ////////////////////////////////////////////////////////////////////////////////
 //
-// Last changed  : $Date: 2014-04-06 15:57:21 +0000 (Sun, 06 Apr 2014) $
-// File revision : $Revision: 4 $
-//
-// $Id: TDStretch.h 195 2014-04-06 15:57:21Z oparviai $
-//
-////////////////////////////////////////////////////////////////////////////////
-//
 // License :
 //
 //  SoundTouch audio processing library
@@ -112,39 +105,47 @@ class TDStretch : public FIFOProcessor
 protected:
     int channels;
     int sampleReq;
-    float tempo;
 
-    SAMPLETYPE *pMidBuffer;
-    SAMPLETYPE *pMidBufferUnaligned;
     int overlapLength;
     int seekLength;
     int seekWindowLength;
-    int overlapDividerBits;
+    int overlapDividerBitsNorm;
+    int overlapDividerBitsPure;
     int slopingDivider;
-    float nominalSkip;
-    float skipFract;
-    FIFOSampleBuffer outputBuffer;
-    FIFOSampleBuffer inputBuffer;
-    bool bQuickSeek;
-
     int sampleRate;
     int sequenceMs;
     int seekWindowMs;
     int overlapMs;
+
+    unsigned long maxnorm;
+    float maxnormf;
+
+    double tempo;
+    double nominalSkip;
+    double skipFract;
+
+    bool bQuickSeek;
     bool bAutoSeqSetting;
     bool bAutoSeekSetting;
+    bool isBeginning;
+
+    SAMPLETYPE *pMidBuffer;
+    SAMPLETYPE *pMidBufferUnaligned;
+
+    FIFOSampleBuffer outputBuffer;
+    FIFOSampleBuffer inputBuffer;
 
     void acceptNewOverlapLength(int newOverlapLength);
 
     virtual void clearCrossCorrState();
     void calculateOverlapLength(int overlapMs);
 
-    virtual double calcCrossCorr(const SAMPLETYPE *mixingPos, const SAMPLETYPE *compare, double &norm) const;
-    virtual double calcCrossCorrAccumulate(const SAMPLETYPE *mixingPos, const SAMPLETYPE *compare, double &norm) const;
+    virtual double calcCrossCorr(const SAMPLETYPE *mixingPos, const SAMPLETYPE *compare, double &norm);
+    virtual double calcCrossCorrAccumulate(const SAMPLETYPE *mixingPos, const SAMPLETYPE *compare, double &norm);
 
     virtual int seekBestOverlapPositionFull(const SAMPLETYPE *refPos);
     virtual int seekBestOverlapPositionQuick(const SAMPLETYPE *refPos);
-    int seekBestOverlapPosition(const SAMPLETYPE *refPos);
+    virtual int seekBestOverlapPosition(const SAMPLETYPE *refPos);
 
     virtual void overlapStereo(SAMPLETYPE *output, const SAMPLETYPE *input) const;
     virtual void overlapMono(SAMPLETYPE *output, const SAMPLETYPE *input) const;
@@ -154,6 +155,7 @@ protected:
     void overlap(SAMPLETYPE *output, const SAMPLETYPE *input, uint ovlPos) const;
 
     void calcSeqParameters();
+    void adaptNormalizer();
 
     /// Changes the tempo of the given sound samples.
     /// Returns amount of samples returned in the "output" buffer.
@@ -182,7 +184,7 @@ public:
 
     /// Sets new target tempo. Normal tempo = 'SCALE', smaller values represent slower 
     /// tempo, larger faster tempo.
-    void setTempo(float newTempo);
+    void setTempo(double newTempo);
 
     /// Returns nonzero if there aren't any samples available for outputting.
     virtual void clear();
@@ -238,8 +240,13 @@ public:
     {
         return seekWindowLength - overlapLength;
     }
-};
 
+	/// return approximate initial input-output latency
+	int getLatency() const
+	{
+		return sampleReq;
+	}
+};
 
 
 // Implementation-specific class declarations:
@@ -249,8 +256,8 @@ public:
     class TDStretchMMX : public TDStretch
     {
     protected:
-        double calcCrossCorr(const short *mixingPos, const short *compare, double &norm) const;
-        double calcCrossCorrAccumulate(const short *mixingPos, const short *compare, double &norm) const;
+        double calcCrossCorr(const short *mixingPos, const short *compare, double &norm);
+        double calcCrossCorrAccumulate(const short *mixingPos, const short *compare, double &norm);
         virtual void overlapStereo(short *output, const short *input) const;
         virtual void clearCrossCorrState();
     };
@@ -262,8 +269,8 @@ public:
     class TDStretchSSE : public TDStretch
     {
     protected:
-        double calcCrossCorr(const float *mixingPos, const float *compare, double &norm) const;
-        double calcCrossCorrAccumulate(const float *mixingPos, const float *compare, double &norm) const;
+        double calcCrossCorr(const float *mixingPos, const float *compare, double &norm);
+        double calcCrossCorrAccumulate(const float *mixingPos, const float *compare, double &norm);
     };
 
 #endif /// SOUNDTOUCH_ALLOW_SSE
diff --git a/media/libsoundtouch/src/cpu_detect.h b/media/libsoundtouch/src/cpu_detect.h
index e7582e8da3..093b6097aa 100644
--- a/media/libsoundtouch/src/cpu_detect.h
+++ b/media/libsoundtouch/src/cpu_detect.h
@@ -12,13 +12,6 @@
 ///
 ////////////////////////////////////////////////////////////////////////////////
 //
-// Last changed  : $Date: 2008-02-10 16:26:55 +0000 (Sun, 10 Feb 2008) $
-// File revision : $Revision: 4 $
-//
-// $Id: cpu_detect.h 11 2008-02-10 16:26:55Z oparviai $
-//
-////////////////////////////////////////////////////////////////////////////////
-//
 // License :
 //
 //  SoundTouch audio processing library
diff --git a/media/libsoundtouch/src/cpu_detect_x86.cpp b/media/libsoundtouch/src/cpu_detect_x86.cpp
index 63f860664a..f0f026b20d 100644
--- a/media/libsoundtouch/src/cpu_detect_x86.cpp
+++ b/media/libsoundtouch/src/cpu_detect_x86.cpp
@@ -11,13 +11,6 @@
 ///
 ////////////////////////////////////////////////////////////////////////////////
 //
-// Last changed  : $Date: 2014-01-07 18:24:28 +0000 (Tue, 07 Jan 2014) $
-// File revision : $Revision: 4 $
-//
-// $Id: cpu_detect_x86.cpp 183 2014-01-07 18:24:28Z oparviai $
-//
-////////////////////////////////////////////////////////////////////////////////
-//
 // License :
 //
 //  SoundTouch audio processing library
@@ -74,7 +67,6 @@ void disableExtensions(uint dwDisableMask)
 }
 
 
-
 /// Checks which instruction set extensions are supported by the CPU.
 uint detectCPUextensions(void)
 {
diff --git a/media/libsoundtouch/src/mmx_optimized.cpp b/media/libsoundtouch/src/mmx_optimized.cpp
index 9062026399..0bc7fe86f7 100644
--- a/media/libsoundtouch/src/mmx_optimized.cpp
+++ b/media/libsoundtouch/src/mmx_optimized.cpp
@@ -20,13 +20,6 @@
 ///
 ////////////////////////////////////////////////////////////////////////////////
 //
-// Last changed  : $Date: 2015-02-22 15:10:38 +0000 (Sun, 22 Feb 2015) $
-// File revision : $Revision: 4 $
-//
-// $Id: mmx_optimized.cpp 206 2015-02-22 15:10:38Z oparviai $
-//
-////////////////////////////////////////////////////////////////////////////////
-//
 // License :
 //
 //  SoundTouch audio processing library
@@ -68,7 +61,7 @@ using namespace soundtouch;
 
 
 // Calculates cross correlation of two buffers
-double TDStretchMMX::calcCrossCorr(const short *pV1, const short *pV2, double &dnorm) const
+double TDStretchMMX::calcCrossCorr(const short *pV1, const short *pV2, double &dnorm)
 {
     const __m64 *pVec1, *pVec2;
     __m64 shifter;
@@ -79,7 +72,7 @@ double TDStretchMMX::calcCrossCorr(const short *pV1, const short *pV2, double &d
     pVec1 = (__m64*)pV1;
     pVec2 = (__m64*)pV2;
 
-    shifter = _m_from_int(overlapDividerBits);
+    shifter = _m_from_int(overlapDividerBitsNorm);
     normaccu = accu = _mm_setzero_si64();
 
     // Process 4 parallel sets of 2 * stereo samples or 4 * mono samples 
@@ -123,6 +116,16 @@ double TDStretchMMX::calcCrossCorr(const short *pV1, const short *pV2, double &d
     // Clear MMS state
     _m_empty();
 
+    if (norm > (long)maxnorm)
+    {
+        // modify 'maxnorm' inside critical section to avoid multi-access conflict if in OpenMP mode
+        #pragma omp critical
+        if (norm > (long)maxnorm)
+        {
+            maxnorm = norm;
+        }
+    }
+
     // Normalize result by dividing by sqrt(norm) - this step is easiest 
     // done using floating point operation
     dnorm = (double)norm;
@@ -134,7 +137,7 @@ double TDStretchMMX::calcCrossCorr(const short *pV1, const short *pV2, double &d
 
 
 /// Update cross-correlation by accumulating "norm" coefficient by previously calculated value
-double TDStretchMMX::calcCrossCorrAccumulate(const short *pV1, const short *pV2, double &dnorm) const
+double TDStretchMMX::calcCrossCorrAccumulate(const short *pV1, const short *pV2, double &dnorm)
 {
     const __m64 *pVec1, *pVec2;
     __m64 shifter;
@@ -146,13 +149,13 @@ double TDStretchMMX::calcCrossCorrAccumulate(const short *pV1, const short *pV2,
     lnorm = 0;
     for (i = 1; i <= channels; i ++)
     {
-        lnorm -= (pV1[-i] * pV1[-i]) >> overlapDividerBits;
+        lnorm -= (pV1[-i] * pV1[-i]) >> overlapDividerBitsNorm;
     }
 
     pVec1 = (__m64*)pV1;
     pVec2 = (__m64*)pV2;
 
-    shifter = _m_from_int(overlapDividerBits);
+    shifter = _m_from_int(overlapDividerBitsNorm);
     accu = _mm_setzero_si64();
 
     // Process 4 parallel sets of 2 * stereo samples or 4 * mono samples 
@@ -191,10 +194,15 @@ double TDStretchMMX::calcCrossCorrAccumulate(const short *pV1, const short *pV2,
     pV1 = (short *)pVec1;
     for (int j = 1; j <= channels; j ++)
     {
-        lnorm += (pV1[-j] * pV1[-j]) >> overlapDividerBits;
+        lnorm += (pV1[-j] * pV1[-j]) >> overlapDividerBitsNorm;
     }
     dnorm += (double)lnorm;
 
+    if (lnorm > (long)maxnorm)
+    {
+        maxnorm = lnorm;
+    }
+
     // Normalize result by dividing by sqrt(norm) - this step is easiest 
     // done using floating point operation
     return (double)corr / sqrt((dnorm < 1e-9) ? 1.0 : dnorm);
@@ -209,7 +217,6 @@ void TDStretchMMX::clearCrossCorrState()
 }
 
 
-
 // MMX-optimized version of the function overlapStereo
 void TDStretchMMX::overlapStereo(short *output, const short *input) const
 {
@@ -233,7 +240,7 @@ void TDStretchMMX::overlapStereo(short *output, const short *input) const
 
     // Overlaplength-division by shifter. "+1" is to account for "-1" deduced in
     // overlapDividerBits calculation earlier.
-    shifter = _m_from_int(overlapDividerBits + 1);
+    shifter = _m_from_int(overlapDividerBitsPure + 1);
 
     for (i = 0; i < overlapLength / 4; i ++)
     {
@@ -325,7 +332,6 @@ void FIRFilterMMX::setCoefficients(const short *coeffs, uint newLength, uint uRe
 }
 
 
-
 // mmx-optimized version of the filter routine for stereo sound
 uint FIRFilterMMX::evaluateFilterStereo(short *dest, const short *src, uint numSamples) const
 {
@@ -382,4 +388,9 @@ uint FIRFilterMMX::evaluateFilterStereo(short *dest, const short *src, uint numS
     return (numSamples & 0xfffffffe) - length;
 }
 
+#else
+
+// workaround to not complain about empty module
+bool _dontcomplain_mmx_empty;
+
 #endif  // SOUNDTOUCH_ALLOW_MMX
diff --git a/media/libsoundtouch/src/moz.build b/media/libsoundtouch/src/moz.build
index 28476773bf..ea3f6c93fa 100644
--- a/media/libsoundtouch/src/moz.build
+++ b/media/libsoundtouch/src/moz.build
@@ -40,6 +40,8 @@ else:
     # Windows need alloca renamed to _alloca
     DEFINES['alloca'] = '_alloca'
 
+DEFINES['BUILDING_SOUNDTOUCH'] = 1
+
 # We allow warnings for third-party code that can be updated from upstream.
 AllowCompilerWarnings()
 
diff --git a/media/libsoundtouch/src/sse_optimized.cpp b/media/libsoundtouch/src/sse_optimized.cpp
index fa622efa55..9c16ea8f89 100644
--- a/media/libsoundtouch/src/sse_optimized.cpp
+++ b/media/libsoundtouch/src/sse_optimized.cpp
@@ -23,13 +23,6 @@
 ///
 ////////////////////////////////////////////////////////////////////////////////
 //
-// Last changed  : $Date: 2015-02-21 21:24:29 +0000 (Sat, 21 Feb 2015) $
-// File revision : $Revision: 4 $
-//
-// $Id: sse_optimized.cpp 202 2015-02-21 21:24:29Z oparviai $
-//
-////////////////////////////////////////////////////////////////////////////////
-//
 // License :
 //
 //  SoundTouch audio processing library
@@ -71,7 +64,7 @@ using namespace soundtouch;
 #include <math.h>
 
 // Calculates cross correlation of two buffers
-double TDStretchSSE::calcCrossCorr(const float *pV1, const float *pV2, double &anorm) const
+double TDStretchSSE::calcCrossCorr(const float *pV1, const float *pV2, double &anorm)
 {
     int i;
     const float *pVec1;
@@ -87,7 +80,7 @@ double TDStretchSSE::calcCrossCorr(const float *pV1, const float *pV2, double &a
     // Compile-time define SOUNDTOUCH_ALLOW_NONEXACT_SIMD_OPTIMIZATION is provided
     // for choosing if this little cheating is allowed.
 
-#ifdef SOUNDTOUCH_ALLOW_NONEXACT_SIMD_OPTIMIZATION
+#ifdef ST_SIMD_AVOID_UNALIGNED
     // Little cheating allowed, return valid correlation only for 
     // aligned locations, meaning every second round for stereo sound.
 
@@ -183,7 +176,7 @@ double TDStretchSSE::calcCrossCorr(const float *pV1, const float *pV2, double &a
 
 
 
-double TDStretchSSE::calcCrossCorrAccumulate(const float *pV1, const float *pV2, double &norm) const
+double TDStretchSSE::calcCrossCorrAccumulate(const float *pV1, const float *pV2, double &norm)
 {
     // call usual calcCrossCorr function because SSE does not show big benefit of 
     // accumulating "norm" value, and also the "norm" rolling algorithm would get 
diff --git a/media/libsoundtouch/update.sh b/media/libsoundtouch/update.sh
index 821e135f15..3894ee69f0 100644
--- a/media/libsoundtouch/update.sh
+++ b/media/libsoundtouch/update.sh
@@ -1,3 +1,4 @@
+#!/bin/bash
 # This Source Code Form is subject to the terms of the Mozilla Public
 # License, v. 2.0. If a copy of the MPL was not distributed with this
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
@@ -44,3 +45,29 @@ done
 # Patch the imported files.
 patch -p1 < moz-libsoundtouch.patch
 
+if [ -d $1/.git ]; then
+  rev=$(cd $1 && git rev-parse --verify HEAD)
+  date=$(cd $1 && git show -s --format=%ci HEAD)
+  dirty=$(cd $1 && git diff-index --name-only HEAD)
+  set +e
+  pre_rev=$(grep -o '[[:xdigit:]]\{40\}' moz.yaml)
+  commits=$(cd $1 && git log --pretty=format:'%h - %s' $pre_rev..$rev)
+  set -e
+fi
+
+if [ -n "$rev" ]; then
+  version=$rev
+  if [ -n "$dirty" ]; then
+    version=$version-dirty
+    echo "WARNING: updating from a dirty git repository."
+  fi
+  sed -i.bak -e "s/^ *release:.*/  release: \"$version ($date)\"/" moz.yaml
+  if [[ ! "$( grep "$version" moz.yaml )" ]]; then
+    echo "Updating moz.yaml failed."
+    exit 1
+  fi
+  rm moz.yaml.bak
+  [[ -n "$commits" ]] && echo -e "Pick commits:\n$commits"
+else
+  echo "Remember to update moz.yaml with the version details."
+fi
diff --git a/media/mp4parse-rust/mp4parse-cargo.patch b/media/mp4parse-rust/mp4parse-cargo.patch
index ce843ce135..e9e0942c56 100644
--- a/media/mp4parse-rust/mp4parse-cargo.patch
+++ b/media/mp4parse-rust/mp4parse-cargo.patch
@@ -5,7 +5,7 @@ index 2c606b4..895739f 100644
 @@ -18,8 +18,7 @@ exclude = [
    "*.mp4",
  ]
- 
+
 -[lib]
 -crate-type = ["lib", "cdylib"]
 +build = false # See bug 1611431 - Generate mp4parse-rust bindings as part of mach build
@@ -15,7 +15,7 @@ index 2c606b4..895739f 100644
 @@ -33,9 +32,6 @@ num-traits = "0.2.0"
  [dev-dependencies]
  env_logger = "0.7.1"
- 
+
 -[build-dependencies]
 -cbindgen = "0.5.2"
 -
diff --git a/media/mp4parse-rust/mp4parse_capi/Cargo.toml b/media/mp4parse-rust/mp4parse_capi/Cargo.toml
index 895739f441..708a16360c 100644
--- a/media/mp4parse-rust/mp4parse_capi/Cargo.toml
+++ b/media/mp4parse-rust/mp4parse_capi/Cargo.toml
@@ -37,4 +37,3 @@ env_logger = "0.7.1"
 # panicking on OOM.  Note that this is only safe within Gecko where the system
 # allocator has been globally overridden (see BMO 1457359).
 mp4parse_fallible = ["mp4parse/mp4parse_fallible"]
-
diff --git a/media/mtransport/nr_timer.cpp b/media/mtransport/nr_timer.cpp
index 466e64cc82..04f431c699 100644
--- a/media/mtransport/nr_timer.cpp
+++ b/media/mtransport/nr_timer.cpp
@@ -49,6 +49,7 @@
 
 #include <string>
 
+#include "nsAutoPtr.h"
 #include "nsCOMPtr.h"
 #include "nsComponentManagerUtils.h"
 #include "nsServiceManagerUtils.h"
diff --git a/media/mtransport/test/ice_unittest.cpp b/media/mtransport/test/ice_unittest.cpp
index 343d9a23df..35e4b93088 100644
--- a/media/mtransport/test/ice_unittest.cpp
+++ b/media/mtransport/test/ice_unittest.cpp
@@ -541,6 +541,18 @@ class IceTestPeer : public sigslot::has_slots<> {
     ASSERT_TRUE(NS_SUCCEEDED(res));
   }
 
+  void SetCtxFlags(bool default_route_only) {
+    test_utils_->sts_target()->Dispatch(
+        WrapRunnable(ice_ctx_, &NrIceCtx::SetCtxFlags, default_route_only),
+        NS_DISPATCH_SYNC);
+  }
+
+  nsTArray<NrIceStunAddr> GetStunAddrs() { return ice_ctx_->GetStunAddrs(); }
+
+  void SetStunAddrs(const nsTArray<NrIceStunAddr>& addrs) {
+    ice_ctx_->SetStunAddrs(addrs);
+  }
+
   void UseNat() { nat_->enabled_ = true; }
 
   void SetTimerDivider(int div) { ice_ctx_->internal_SetTimerAccelarator(div); }
@@ -2558,6 +2570,51 @@ TEST_F(WebRtcIceConnectTest, TestConnectIceRestartRoleConflict) {
   p3_ = nullptr;
 }
 
+TEST_F(WebRtcIceConnectTest,
+       TestIceRestartWithMultipleInterfacesAndUserStartingScreenSharing) {
+  const char* FAKE_WIFI_ADDR = "10.0.0.1";
+  const char* FAKE_WIFI_IF_NAME = "wlan9";
+
+  // prepare a fake wifi interface
+  nr_local_addr wifi_addr;
+  wifi_addr.interface.type = NR_INTERFACE_TYPE_WIFI;
+  wifi_addr.interface.estimated_speed = 1000;
+
+  int r = nr_str_port_to_transport_addr(FAKE_WIFI_ADDR, 0, IPPROTO_UDP,
+                                        &(wifi_addr.addr));
+  ASSERT_EQ(0, r);
+  strncpy(wifi_addr.addr.ifname, FAKE_WIFI_IF_NAME, MAXIFNAME);
+
+  // setup initial ICE connection between p1_ and p2_
+  UseNat();
+  AddStream(1);
+  SetExpectedTypes(NrIceCandidate::Type::ICE_SERVER_REFLEXIVE,
+                   NrIceCandidate::Type::ICE_SERVER_REFLEXIVE);
+  ASSERT_TRUE(Gather(kDefaultTimeout, true));
+  Connect();
+
+  // verify the connection is working
+  SendReceive(p1_.get(), p2_.get());
+
+  // simulate user accepting permissions for screen sharing
+  p2_->SetCtxFlags(false);
+
+  // and having an additional non-default interface
+  nsTArray<NrIceStunAddr> stunAddr = p2_->GetStunAddrs();
+  stunAddr.InsertElementAt(0, NrIceStunAddr(&wifi_addr));
+  p2_->SetStunAddrs(stunAddr);
+
+  std::cout << "-------------------------------------------------" << std::endl;
+
+  // now restart ICE
+  p2_->RestartIce();
+  ASSERT_FALSE(p2_->gathering_complete());
+
+  // verify that we can successfully gather candidates
+  p2_->Gather();
+  EXPECT_TRUE_WAIT(p2_->gathering_complete(), kDefaultTimeout);
+}
+
 TEST_F(WebRtcIceConnectTest, TestConnectTcp) {
   Init(false, true);
   AddStream(1);
diff --git a/media/mtransport/third_party/nICEr/src/ice/ice_ctx.c b/media/mtransport/third_party/nICEr/src/ice/ice_ctx.c
index ce35141562..104fb774d8 100644
--- a/media/mtransport/third_party/nICEr/src/ice/ice_ctx.c
+++ b/media/mtransport/third_party/nICEr/src/ice/ice_ctx.c
@@ -693,10 +693,6 @@ int nr_ice_set_local_addresses(nr_ice_ctx *ctx,
     nr_local_addr default_addrs[2];
     int default_addr_ct = 0;
 
-    if (ctx->local_addrs) {
-      r_log(LOG_ICE,LOG_WARNING,"ICE(%s): local addresses already set, no work to do",ctx->label);
-      ABORT(R_ALREADY);
-    }
     if (!stun_addrs || !stun_addr_ct) {
       r_log(LOG_ICE,LOG_ERR,"ICE(%s): no stun addrs provided",ctx->label);
       ABORT(R_BAD_ARGS);
@@ -769,7 +765,7 @@ int nr_ice_set_local_addresses(nr_ice_ctx *ctx,
     /* Sort interfaces by preference */
     if(ctx->interface_prioritizer) {
       for(i=0;i<addr_ct;i++){
-        if(r=nr_interface_prioritizer_add_interface(ctx->interface_prioritizer,addrs+i)) {
+        if((r=nr_interface_prioritizer_add_interface(ctx->interface_prioritizer,addrs+i)) && (r!=R_ALREADY)) {
           r_log(LOG_ICE,LOG_ERR,"ICE(%s): unable to add interface ",ctx->label);
           ABORT(r);
         }
diff --git a/media/mtransport/transportlayerdtls.cpp b/media/mtransport/transportlayerdtls.cpp
index 49459e2be4..d84d354e92 100644
--- a/media/mtransport/transportlayerdtls.cpp
+++ b/media/mtransport/transportlayerdtls.cpp
@@ -435,6 +435,17 @@ nsresult TransportLayerDtls::SetVerificationDigest(const DtlsDigest& digest) {
   return NS_OK;
 }
 
+void TransportLayerDtls::SetMinMaxVersion(Version min_version,
+                                          Version max_version) {
+  if (min_version < Version::DTLS_1_0 || min_version > Version::DTLS_1_3 ||
+      max_version < Version::DTLS_1_0 || max_version > Version::DTLS_1_3 ||
+      min_version > max_version || max_version < min_version) {
+    return;
+  }
+  minVersion_ = min_version;
+  maxVersion_ = max_version;
+}
+
 // These are the named groups that we will allow.
 static const SSLNamedGroup NamedGroupPreferences[] = {
     ssl_grp_ec_curve25519, ssl_grp_ec_secp256r1, ssl_grp_ec_secp384r1,
@@ -520,10 +531,8 @@ bool TransportLayerDtls::Setup() {
     }
   }
 
-  // Require TLS 1.1 or 1.2. Perhaps some day in the future we will allow TLS
-  // 1.0 for stream modes.
-  SSLVersionRange version_range = {SSL_LIBRARY_VERSION_TLS_1_1,
-                                   SSL_LIBRARY_VERSION_TLS_1_2};
+  SSLVersionRange version_range = {static_cast<PRUint16>(minVersion_),
+                                   static_cast<PRUint16>(maxVersion_)};
 
   rv = SSL_VersionRangeSet(ssl_fd.get(), &version_range);
   if (rv != SECSuccess) {
diff --git a/media/mtransport/transportlayerdtls.h b/media/mtransport/transportlayerdtls.h
index 7740e55941..141a420768 100644
--- a/media/mtransport/transportlayerdtls.h
+++ b/media/mtransport/transportlayerdtls.h
@@ -22,6 +22,7 @@
 #include "dtlsidentity.h"
 #include "transportlayer.h"
 #include "ssl.h"
+#include "sslproto.h"
 
 namespace mozilla {
 
@@ -65,6 +66,13 @@ class TransportLayerDtls final : public TransportLayer {
   void SetRole(Role role) { role_ = role; }
   Role role() { return role_; }
 
+  enum class Version : uint16_t {
+    DTLS_1_0 = SSL_LIBRARY_VERSION_DTLS_1_0,
+    DTLS_1_2 = SSL_LIBRARY_VERSION_DTLS_1_2,
+    DTLS_1_3 = SSL_LIBRARY_VERSION_DTLS_1_3
+  };
+  void SetMinMaxVersion(Version min_version, Version max_version);
+
   void SetIdentity(const RefPtr<DtlsIdentity>& identity) {
     identity_ = identity;
   }
@@ -157,6 +165,9 @@ class TransportLayerDtls final : public TransportLayer {
   Verification verification_mode_ = VERIFY_UNSET;
   std::vector<DtlsDigest> digests_;
 
+  Version minVersion_ = Version::DTLS_1_0;
+  Version maxVersion_ = Version::DTLS_1_2;
+
   // Must delete nspr_io_adapter after ssl_fd_ b/c ssl_fd_ causes an alert
   // (ssl_fd_ contains an un-owning pointer to nspr_io_adapter_)
   UniquePtr<TransportLayerNSPRAdapter> nspr_io_adapter_ = nullptr;
diff --git a/media/webrtc/signaling/gtest/mediapipeline_unittest.cpp b/media/webrtc/signaling/gtest/mediapipeline_unittest.cpp
index cd68bac61c..1f75727352 100644
--- a/media/webrtc/signaling/gtest/mediapipeline_unittest.cpp
+++ b/media/webrtc/signaling/gtest/mediapipeline_unittest.cpp
@@ -37,61 +37,74 @@ static MtransportTestUtils* test_utils;
 
 namespace {
 
-class FakeMediaStreamTrackSource : public mozilla::dom::MediaStreamTrackSource {
+class FakeAudioTrack : public mozilla::ProcessedMediaTrack {
  public:
-  FakeMediaStreamTrackSource() : MediaStreamTrackSource(nullptr, nsString()) {}
-
-  virtual mozilla::dom::MediaSourceEnum GetMediaSource() const override {
-    return mozilla::dom::MediaSourceEnum::Microphone;
+  FakeAudioTrack()
+      : ProcessedMediaTrack(44100, MediaSegment::AUDIO, nullptr),
+        mMutex("Fake AudioTrack") {
+    Resume();
   }
 
-  virtual void Disable() override {}
-
-  virtual void Enable() override {}
-
-  virtual void Stop() override {}
-};
-
-class FakeAudioStreamTrack : public mozilla::dom::AudioStreamTrack {
- public:
-  FakeAudioStreamTrack()
-      : AudioStreamTrack(nullptr, nullptr, new FakeMediaStreamTrackSource(),
-                         mozilla::dom::MediaStreamTrackState::Ended),
-        mMutex("Fake AudioStreamTrack"),
-        mStop(false),
-        mCount(0) {
-    NS_NewTimerWithFuncCallback(
-        getter_AddRefs(mTimer), FakeAudioStreamTrackGenerateData, this, 20,
-        nsITimer::TYPE_REPEATING_SLACK,
-        "FakeAudioStreamTrack::FakeAudioStreamTrackGenerateData",
-        test_utils->sts_target());
+  void Destroy() override {
+    MOZ_ASSERT(!mMainThreadDestroyed);
+    mMainThreadDestroyed = true;
+    Suspend();
   }
 
-  void Stop() {
+  void QueueSetAutoend(bool) override {}
+
+  void Suspend() override {
     mozilla::MutexAutoLock lock(mMutex);
-    mStop = true;
+    if (mSuspended) {
+      return;
+    }
+    mSuspended = true;
     mTimer->Cancel();
+    mTimer = nullptr;
   }
 
-  virtual void AddListener(MediaTrackListener* aListener) override {
+  void Resume() override {
     mozilla::MutexAutoLock lock(mMutex);
-    mListeners.push_back(aListener);
+    if (!mSuspended) {
+      return;
+    }
+    mSuspended = false;
+    NS_NewTimerWithFuncCallback(
+        getter_AddRefs(mTimer), FakeAudioTrackGenerateData, this, 20,
+        nsITimer::TYPE_REPEATING_SLACK,
+        "FakeAudioTrack::FakeAudioTrackGenerateData", test_utils->sts_target());
   }
 
+  void AddListener(MediaTrackListener* aListener) override {
+    mozilla::MutexAutoLock lock(mMutex);
+    MOZ_ASSERT(!mListener);
+    mListener = aListener;
+  }
+
+  RefPtr<GenericPromise> RemoveListener(
+      MediaTrackListener* aListener) override {
+    mozilla::MutexAutoLock lock(mMutex);
+    MOZ_ASSERT(mListener == aListener);
+    mListener = nullptr;
+    return GenericPromise::CreateAndResolve(true, __func__);
+  }
+
+  void ProcessInput(GraphTime aFrom, GraphTime aTo, uint32_t aFlags) override {}
+
  private:
-  std::vector<MediaTrackListener*> mListeners;
   mozilla::Mutex mMutex;
-  bool mStop;
+  MediaTrackListener* mListener = nullptr;
+  bool mSuspended = true;
   nsCOMPtr<nsITimer> mTimer;
-  int mCount;
+  int mCount = 0;
 
-  static void FakeAudioStreamTrackGenerateData(nsITimer* timer, void* closure) {
-    auto mst = static_cast<FakeAudioStreamTrack*>(closure);
+  static void FakeAudioTrackGenerateData(nsITimer* timer, void* closure) {
+    auto t = static_cast<FakeAudioTrack*>(closure);
     const int AUDIO_BUFFER_SIZE = 1600;
     const int NUM_CHANNELS = 2;
 
-    mozilla::MutexAutoLock lock(mst->mMutex);
-    if (mst->mStop) {
+    mozilla::MutexAutoLock lock(t->mMutex);
+    if (t->mSuspended) {
       return;
     }
 
@@ -100,8 +113,8 @@ class FakeAudioStreamTrack : public mozilla::dom::AudioStreamTrack {
     int16_t* data = reinterpret_cast<int16_t*>(samples->Data());
     for (int i = 0; i < (AUDIO_BUFFER_SIZE * NUM_CHANNELS); i++) {
       // saw tooth audio sample
-      data[i] = ((mst->mCount % 8) * 4000) - (7 * 4000) / 2;
-      mst->mCount++;
+      data[i] = ((t->mCount % 8) * 4000) - (7 * 4000) / 2;
+      t->mCount++;
     }
 
     mozilla::AudioSegment segment;
@@ -110,8 +123,8 @@ class FakeAudioStreamTrack : public mozilla::dom::AudioStreamTrack {
     segment.AppendFrames(samples.forget(), channels, AUDIO_BUFFER_SIZE,
                          PRINCIPAL_HANDLE_NONE);
 
-    for (auto& listener : mst->mListeners) {
-      listener->NotifyQueuedChanges(nullptr, 0, segment);
+    if (t->mListener) {
+      t->mListener->NotifyQueuedChanges(nullptr, 0, segment);
     }
   }
 };
@@ -192,9 +205,8 @@ class LoopbackTransport : public MediaTransportHandler {
 
   void UpdateNetworkState(bool aOnline) override {}
 
-  RefPtr<StatsPromise> GetIceStats(
-      const std::string& aTransportId, DOMHighResTimeStamp aNow,
-      std::unique_ptr<dom::RTCStatsReportInternal>&& aReport) override {
+  RefPtr<dom::RTCStatsPromise> GetIceStats(const std::string& aTransportId,
+                                           DOMHighResTimeStamp aNow) override {
     return nullptr;
   }
 
@@ -221,7 +233,8 @@ class TestAgent {
   TestAgent()
       : audio_config_(109, "opus", 48000, 2, false),
         audio_conduit_(mozilla::AudioSessionConduit::Create(
-            WebRtcCallWrapper::Create(), test_utils->sts_target())),
+            WebRtcCallWrapper::Create(dom::RTCStatsTimestampMaker()),
+            test_utils->sts_target())),
         audio_pipeline_(),
         transport_(new LoopbackTransport) {}
 
@@ -233,20 +246,22 @@ class TestAgent {
 
   void SetState(const std::string& aTransportId, TransportLayer::State aState,
                 bool aRtcp) {
-    mozilla::SyncRunnable::DispatchToThread(
-        test_utils->sts_target(),
+    test_utils->sts_target()->Dispatch(
         WrapRunnable(transport_, &LoopbackTransport::SetState, aTransportId,
-                     aState, aRtcp));
+                     aState, aRtcp),
+        nsISerialEventTarget::DISPATCH_SYNC);
   }
 
   void UpdateTransport(const std::string& aTransportId,
                        UniquePtr<MediaPipelineFilter>&& aFilter) {
-    auto sync = MakeRefPtr<mozilla::SyncRunnable>(NS_NewRunnableFunction(
-        __func__, [pipeline = audio_pipeline_, aTransportId,
-                   filter = std::move(aFilter)]() mutable {
-          pipeline->UpdateTransport_s(aTransportId, std::move(filter));
-        }));
-    sync->DispatchToThread(test_utils->sts_target());
+    test_utils->sts_target()->Dispatch(
+        NS_NewRunnableFunction(__func__,
+                               [pipeline = audio_pipeline_, aTransportId,
+                                filter = std::move(aFilter)]() mutable {
+                                 pipeline->UpdateTransport_s(aTransportId,
+                                                             std::move(filter));
+                               }),
+        nsISerialEventTarget::DISPATCH_SYNC);
   }
 
   void Stop() {
@@ -259,10 +274,10 @@ class TestAgent {
 
   void Shutdown() {
     if (audio_pipeline_) audio_pipeline_->Shutdown_m();
-    if (audio_stream_track_) audio_stream_track_->Stop();
 
-    mozilla::SyncRunnable::DispatchToThread(
-        test_utils->sts_target(), WrapRunnable(this, &TestAgent::Shutdown_s));
+    test_utils->sts_target()->Dispatch(
+        WrapRunnable(this, &TestAgent::Shutdown_s),
+        nsISerialEventTarget::DISPATCH_SYNC);
   }
 
   uint32_t GetRemoteSSRC() {
@@ -292,7 +307,7 @@ class TestAgent {
  protected:
   mozilla::AudioCodecConfig audio_config_;
   RefPtr<mozilla::MediaSessionConduit> audio_conduit_;
-  RefPtr<FakeAudioStreamTrack> audio_stream_track_;
+  RefPtr<FakeAudioTrack> audio_track_;
   // TODO(bcampen@mozilla.com): Right now this does not let us test RTCP in
   // both directions; only the sender's RTCP is sent, but the receiver should
   // be sending it too.
@@ -308,7 +323,7 @@ class TestAgentSend : public TestAgent {
             ->ConfigureSendMediaCodec(&audio_config_);
     EXPECT_EQ(mozilla::kMediaConduitNoError, err);
 
-    audio_stream_track_ = new FakeAudioStreamTrack();
+    audio_track_ = new FakeAudioTrack();
   }
 
   virtual void CreatePipeline(const std::string& aTransportId) {
@@ -319,7 +334,7 @@ class TestAgentSend : public TestAgent {
                                            test_utils->sts_target(), false,
                                            audio_conduit_);
 
-    audio_pipeline->SetTrack(audio_stream_track_.get());
+    audio_pipeline->SetSendTrack(audio_track_);
     audio_pipeline->Start();
 
     audio_pipeline_ = audio_pipeline;
@@ -366,6 +381,15 @@ class TestAgentReceive : public TestAgent {
   UniquePtr<MediaPipelineFilter> bundle_filter_;
 };
 
+void WaitFor(TimeDuration aDuration) {
+  bool done = false;
+  NS_DelayedDispatchToCurrentThread(
+      NS_NewRunnableFunction(__func__, [&] { done = true; }),
+      aDuration.ToMilliseconds());
+  SpinEventLoopUntil<ProcessFailureBehavior::IgnoreAndContinue>(
+      [&] { return done; });
+}
+
 class MediaPipelineTest : public ::testing::Test {
  public:
   ~MediaPipelineTest() {
@@ -381,9 +405,9 @@ class MediaPipelineTest : public ::testing::Test {
 
   // Setup transport.
   void InitTransports() {
-    mozilla::SyncRunnable::DispatchToThread(
-        test_utils->sts_target(),
-        WrapRunnableNM(&TestAgent::Connect, &p2_, &p1_));
+    test_utils->sts_target()->Dispatch(
+        WrapRunnableNM(&TestAgent::Connect, &p2_, &p1_),
+        nsISerialEventTarget::DISPATCH_SYNC);
   }
 
   // Verify RTP and RTCP
@@ -414,7 +438,7 @@ class MediaPipelineTest : public ::testing::Test {
     p2_.SetState(transportId, TransportLayer::TS_CONNECTING, false);
     p2_.SetState(transportId, TransportLayer::TS_CONNECTING, true);
 
-    PR_Sleep(10);
+    WaitFor(TimeDuration::FromMilliseconds(10));
 
     // Set state of transports to OPEN (ie; connected). This should result in
     // media flowing.
@@ -424,7 +448,7 @@ class MediaPipelineTest : public ::testing::Test {
     p2_.SetState(transportId, TransportLayer::TS_OPEN, true);
 
     if (bundle) {
-      PR_Sleep(ms_until_filter_update);
+      WaitFor(TimeDuration::FromMilliseconds(ms_until_filter_update));
 
       // Leaving refinedFilter not set implies we want to just update with
       // the other side's SSRC
@@ -438,13 +462,13 @@ class MediaPipelineTest : public ::testing::Test {
     }
 
     // wait for some RTP/RTCP tx and rx to happen
-    PR_Sleep(ms_of_traffic_after_answer);
+    WaitFor(TimeDuration::FromMilliseconds(ms_of_traffic_after_answer));
 
     p1_.Stop();
     p2_.Stop();
 
     // wait for any packets in flight to arrive
-    PR_Sleep(100);
+    WaitFor(TimeDuration::FromMilliseconds(200));
 
     p1_.Shutdown();
     p2_.Shutdown();
diff --git a/media/webrtc/signaling/gtest/rtpsources_unittests.cpp b/media/webrtc/signaling/gtest/rtpsources_unittests.cpp
index 5be6b4b4ef..8d0231196c 100644
--- a/media/webrtc/signaling/gtest/rtpsources_unittests.cpp
+++ b/media/webrtc/signaling/gtest/rtpsources_unittests.cpp
@@ -33,7 +33,7 @@ class RtpSourcesTest : public ::testing::Test {
     const int64_t times[] = {100, 120, 140, 160, 180, 200, 220};
     const size_t numEntries = sizeof(times) / sizeof(times[0]);
     for (auto i : times) {
-      history.Insert(i, i + jitter, hasAudioLevel, audioLevel);
+      history.Insert(i, i + jitter, i, hasAudioLevel, audioLevel);
     }
     ASSERT_EQ(history.mDetailedHistory.size(), numEntries);
     for (auto i : times) {
@@ -66,25 +66,25 @@ class RtpSourcesTest : public ::testing::Test {
     constexpr int64_t pruneTime1 = time2 + (10 * 1000) + 1;
 
     // time0
-    history.Insert(timeNow, time0, true, 0);
+    history.Insert(timeNow, time0, 0, true, 0);
     EXPECT_TRUE(history.Empty());
     EXPECT_FALSE(history.mHasEvictedEntry);
 
     // time1
-    history.Insert(timeNow, time1, true, 0);
+    history.Insert(timeNow, time1, 1, true, 0);
     // Check that the jitter window buffer hasn't been used
     EXPECT_TRUE(history.Empty());
     ASSERT_EQ(history.mLatestEviction.jitterAdjustedTimestamp, time1);
     EXPECT_TRUE(history.mHasEvictedEntry);
 
     // time2
-    history.Insert(timeNow, time2, true, 0);
+    history.Insert(timeNow, time2, 2, true, 0);
     EXPECT_TRUE(history.Empty());
     ASSERT_EQ(history.mLatestEviction.jitterAdjustedTimestamp, time2);
     EXPECT_TRUE(history.mHasEvictedEntry);
 
     // time3
-    history.Insert(timeNow, time3, true, 0);
+    history.Insert(timeNow, time3, 3, true, 0);
     EXPECT_TRUE(history.Empty());
     ASSERT_EQ(history.mLatestEviction.jitterAdjustedTimestamp, time2);
     EXPECT_TRUE(history.mHasEvictedEntry);
@@ -116,7 +116,7 @@ class RtpSourcesTest : public ::testing::Test {
     constexpr int64_t timeNow2 = time1 + jitterWindow + 1;
 
     // time0
-    history.Insert(timeNow0, time0, false, 1);
+    history.Insert(timeNow0, time0, 0, false, 1);
     EXPECT_FALSE(history.Empty());
     // Jitter window should not have grown
     ASSERT_EQ(history.mMaxJitterWindow, jitterWindow);
@@ -124,7 +124,7 @@ class RtpSourcesTest : public ::testing::Test {
     EXPECT_FALSE(history.mHasEvictedEntry);
 
     // time1
-    history.Insert(timeNow0, time1, true, 2);
+    history.Insert(timeNow0, time1, 1, true, 2);
     ASSERT_EQ(history.mMaxJitterWindow, jitterWindow);
     EXPECT_EQ(history.mDetailedHistory.size(), static_cast<size_t>(2));
     EXPECT_FALSE(history.mHasEvictedEntry);
@@ -153,6 +153,7 @@ class RtpSourcesTest : public ::testing::Test {
     RtpSourceHistory history;
     constexpr int64_t timeNow = 0;
     const int64_t jitterAdjusted = timeNow + 10;
+    const uint32_t ntpTimestamp = 0;
     const bool hasAudioLevel = true;
     const uint8_t audioLevel0 = 127;
     // should result in in hasAudioLevel = false
@@ -161,7 +162,8 @@ class RtpSourcesTest : public ::testing::Test {
     const uint8_t audioLevel2 = 128;
 
     // audio level 0
-    history.Insert(timeNow, jitterAdjusted, hasAudioLevel, audioLevel0);
+    history.Insert(timeNow, jitterAdjusted, ntpTimestamp, hasAudioLevel,
+                   audioLevel0);
     ASSERT_FALSE(history.mHasEvictedEntry);
     EXPECT_EQ(history.mDetailedHistory.size(), static_cast<size_t>(1));
     {
@@ -171,7 +173,8 @@ class RtpSourcesTest : public ::testing::Test {
       EXPECT_EQ(entry->audioLevel, audioLevel0);
     }
     // audio level 1
-    history.Insert(timeNow, jitterAdjusted, hasAudioLevel, audioLevel1);
+    history.Insert(timeNow, jitterAdjusted, ntpTimestamp, hasAudioLevel,
+                   audioLevel1);
     ASSERT_FALSE(history.mHasEvictedEntry);
     EXPECT_EQ(history.mDetailedHistory.size(), static_cast<size_t>(1));
     {
@@ -181,7 +184,8 @@ class RtpSourcesTest : public ::testing::Test {
       EXPECT_EQ(entry->audioLevel, audioLevel1);
     }
     // audio level 2
-    history.Insert(timeNow, jitterAdjusted, hasAudioLevel, audioLevel2);
+    history.Insert(timeNow, jitterAdjusted, ntpTimestamp, hasAudioLevel,
+                   audioLevel2);
     ASSERT_FALSE(history.mHasEvictedEntry);
     EXPECT_EQ(history.mDetailedHistory.size(), static_cast<size_t>(1));
     {
@@ -207,8 +211,9 @@ class RtpSourcesTest : public ::testing::Test {
     constexpr int64_t timeNow = 10000;
     constexpr int64_t jitter = RtpSourceHistory::kMinJitterWindow / 2;
     const int64_t jitterAdjusted = timeNow + jitter;
+    const uint32_t ntpTimestamp = 0;
 
-    history.Insert(timeNow, jitterAdjusted, 0, false);
+    history.Insert(timeNow, jitterAdjusted, ntpTimestamp, false, 0);
     history.Prune(timeNow + (jitter * 3) + 1);
     EXPECT_EQ(history.mDetailedHistory.size(), static_cast<size_t>(0));
     EXPECT_TRUE(history.mHasEvictedEntry);
diff --git a/media/webrtc/signaling/src/media-conduit/AudioConduit.cpp b/media/webrtc/signaling/src/media-conduit/AudioConduit.cpp
index dcfdd4b5dc..00386cf73c 100644
--- a/media/webrtc/signaling/src/media-conduit/AudioConduit.cpp
+++ b/media/webrtc/signaling/src/media-conduit/AudioConduit.cpp
@@ -291,22 +291,26 @@ void WebrtcAudioConduit::GetRtpSources(
 // test-only: inserts a CSRC entry in a RtpSourceObserver's history for
 // getContributingSources mochitests
 void InsertAudioLevelForContributingSource(RtpSourceObserver& observer,
-                                           uint32_t aCsrcSource,
-                                           int64_t aTimestamp,
-                                           bool aHasAudioLevel,
-                                           uint8_t aAudioLevel) {
+                                           const uint32_t aCsrcSource,
+                                           const int64_t aTimestamp,
+                                           const uint32_t aRtpTimestamp,
+                                           const bool aHasAudioLevel,
+                                           const uint8_t aAudioLevel) {
   using EntryType = dom::RTCRtpSourceEntryType;
   auto key = RtpSourceObserver::GetKey(aCsrcSource, EntryType::Contributing);
   auto& hist = observer.mRtpSources[key];
-  hist.Insert(aTimestamp, aTimestamp, aHasAudioLevel, aAudioLevel);
+  hist.Insert(aTimestamp, aTimestamp, aRtpTimestamp, aHasAudioLevel,
+              aAudioLevel);
 }
 
 void WebrtcAudioConduit::InsertAudioLevelForContributingSource(
-    uint32_t aCsrcSource, int64_t aTimestamp, bool aHasAudioLevel,
-    uint8_t aAudioLevel) {
+    const uint32_t aCsrcSource, const int64_t aTimestamp,
+    const uint32_t aRtpTimestamp, const bool aHasAudioLevel,
+    const uint8_t aAudioLevel) {
   MOZ_ASSERT(NS_IsMainThread());
   mozilla::InsertAudioLevelForContributingSource(
-      mRtpSourceObserver, aCsrcSource, aTimestamp, aHasAudioLevel, aAudioLevel);
+      mRtpSourceObserver, aCsrcSource, aTimestamp, aRtpTimestamp,
+      aHasAudioLevel, aAudioLevel);
 }
 
 /*
@@ -716,9 +720,20 @@ MediaConduitErrorCode WebrtcAudioConduit::ReceivedRTCPPacket(const void* data,
     CSFLogError(LOGTAG, "%s RTCP Processing Failed", __FUNCTION__);
     return kMediaConduitRTPProcessingFailed;
   }
+
+  // TODO(bug 1496533): We will need to keep separate timestamps for each SSRC,
+  // and for each SSRC we will need to keep a timestamp for SR and RR.
+  mLastRtcpReceived = Some(GetNow());
   return kMediaConduitNoError;
 }
 
+// TODO(bug 1496533): We will need to add a type (ie; SR or RR) param here, or
+// perhaps break this function into two functions, one for each type.
+Maybe<DOMHighResTimeStamp> WebrtcAudioConduit::LastRtcpReceived() const {
+  ASSERT_ON_THREAD(mStsThread);
+  return mLastRtcpReceived;
+}
+
 MediaConduitErrorCode WebrtcAudioConduit::StopTransmitting() {
   MOZ_ASSERT(NS_IsMainThread());
   MutexAutoLock lock(mMutex);
diff --git a/media/webrtc/signaling/src/media-conduit/AudioConduit.h b/media/webrtc/signaling/src/media-conduit/AudioConduit.h
index f2553b9414..fece3d4db0 100644
--- a/media/webrtc/signaling/src/media-conduit/AudioConduit.h
+++ b/media/webrtc/signaling/src/media-conduit/AudioConduit.h
@@ -52,6 +52,8 @@ class WebrtcAudioConduit : public AudioSessionConduit,
    * feed in received RTCP Frames to the VoiceEngine for decoding
    */
   MediaConduitErrorCode ReceivedRTCPPacket(const void* data, int len) override;
+  Maybe<DOMHighResTimeStamp> LastRtcpReceived() const override;
+  DOMHighResTimeStamp GetNow() const override { return mCall->GetNow(); }
 
   MediaConduitErrorCode StopTransmitting() override;
   MediaConduitErrorCode StartTransmitting() override;
@@ -245,9 +247,11 @@ class WebrtcAudioConduit : public AudioSessionConduit,
                    const int64_t aTimestamp, const uint32_t aJitter) override;
 
   // test-only: inserts fake CSRCs and audio level data
-  void InsertAudioLevelForContributingSource(uint32_t aSource,
-                                             int64_t aTimestamp, bool aHasLevel,
-                                             uint8_t aLevel);
+  void InsertAudioLevelForContributingSource(const uint32_t aCsrcSource,
+                                             const int64_t aTimestamp,
+                                             const uint32_t aRtpTimestamp,
+                                             const bool aHasAudioLevel,
+                                             const uint8_t aAudioLevel);
 
   bool IsSamplingFreqSupported(int freq) const override;
 
@@ -355,6 +359,9 @@ class WebrtcAudioConduit : public AudioSessionConduit,
 
   // Accessed from mStsThread. Last successfully polled RTT
   Maybe<DOMHighResTimeStamp> mRttSec;
+
+  // Accessed only on mStsThread
+  Maybe<DOMHighResTimeStamp> mLastRtcpReceived;
 };
 
 }  // namespace mozilla
diff --git a/media/webrtc/signaling/src/media-conduit/MediaConduitInterface.h b/media/webrtc/signaling/src/media-conduit/MediaConduitInterface.h
index f6c33aa087..a5ab657b98 100644
--- a/media/webrtc/signaling/src/media-conduit/MediaConduitInterface.h
+++ b/media/webrtc/signaling/src/media-conduit/MediaConduitInterface.h
@@ -15,6 +15,7 @@
 #include "CodecConfig.h"
 #include "VideoTypes.h"
 #include "MediaConduitErrors.h"
+#include "RTCStatsReport.h"
 
 #include "ImageContainer.h"
 
@@ -160,6 +161,9 @@ class MediaSessionConduit {
   virtual MediaConduitErrorCode ReceivedRTCPPacket(const void* data,
                                                    int len) = 0;
 
+  virtual Maybe<DOMHighResTimeStamp> LastRtcpReceived() const = 0;
+  virtual DOMHighResTimeStamp GetNow() const = 0;
+
   virtual MediaConduitErrorCode StopTransmitting() = 0;
   virtual MediaConduitErrorCode StartTransmitting() = 0;
   virtual MediaConduitErrorCode StopReceiving() = 0;
@@ -258,7 +262,10 @@ class WebRtcCallWrapper : public RefCounted<WebRtcCallWrapper> {
  public:
   typedef webrtc::Call::Config Config;
 
-  static RefPtr<WebRtcCallWrapper> Create() { return new WebRtcCallWrapper(); }
+  static RefPtr<WebRtcCallWrapper> Create(
+      const dom::RTCStatsTimestampMaker& aTimestampMaker) {
+    return new WebRtcCallWrapper(aTimestampMaker);
+  }
 
   static RefPtr<WebRtcCallWrapper> Create(UniquePtr<webrtc::Call>&& aCall) {
     return new WebRtcCallWrapper(std::move(aCall));
@@ -300,12 +307,15 @@ class WebRtcCallWrapper : public RefCounted<WebRtcCallWrapper> {
     mConduits.erase(conduit);
   }
 
+  DOMHighResTimeStamp GetNow() const { return mTimestampMaker.GetNow(); }
+
   MOZ_DECLARE_REFCOUNTED_TYPENAME(WebRtcCallWrapper)
 
   rtc::scoped_refptr<webrtc::AudioDecoderFactory> mDecoderFactory;
 
  private:
-  WebRtcCallWrapper() {
+  explicit WebRtcCallWrapper(const dom::RTCStatsTimestampMaker& aTimestampMaker)
+      : mTimestampMaker(aTimestampMaker) {
     auto voice_engine = webrtc::VoiceEngine::Create();
     mDecoderFactory = webrtc::CreateBuiltinAudioDecoderFactory();
 
@@ -335,6 +345,7 @@ class WebRtcCallWrapper : public RefCounted<WebRtcCallWrapper> {
   // Allows conduits to know about one another, to avoid remote SSRC
   // collisions.
   std::set<MediaSessionConduit*> mConduits;
+  dom::RTCStatsTimestampMaker mTimestampMaker;
 };
 
 // Abstract base classes for external encoder/decoder.
diff --git a/media/webrtc/signaling/src/media-conduit/RtpSourceObserver.cpp b/media/webrtc/signaling/src/media-conduit/RtpSourceObserver.cpp
index c28b43a374..394e20392b 100644
--- a/media/webrtc/signaling/src/media-conduit/RtpSourceObserver.cpp
+++ b/media/webrtc/signaling/src/media-conduit/RtpSourceObserver.cpp
@@ -30,8 +30,8 @@ void RtpSourceObserver::OnRtpPacket(const webrtc::RTPHeader& aHeader,
     auto& hist = mRtpSources[GetKey(aHeader.ssrc, EntryType::Synchronization)];
     hist.Prune(aTimestamp);
     // ssrc-audio-level handling
-    hist.Insert(aTimestamp, jitterAdjusted, aHeader.extension.hasAudioLevel,
-                aHeader.extension.audioLevel);
+    hist.Insert(aTimestamp, jitterAdjusted, aHeader.timestamp,
+                aHeader.extension.hasAudioLevel, aHeader.extension.audioLevel);
 
     // csrc-audio-level handling
     const auto& list = aHeader.extension.csrcAudioLevels;
@@ -41,7 +41,8 @@ void RtpSourceObserver::OnRtpPacket(const webrtc::RTPHeader& aHeader,
       hist.Prune(aTimestamp);
       bool hasLevel = i < list.numAudioLevels;
       uint8_t level = hasLevel ? list.arrOfAudioLevels[i] : 0;
-      hist.Insert(aTimestamp, jitterAdjusted, hasLevel, level);
+      hist.Insert(aTimestamp, jitterAdjusted, aHeader.timestamp, hasLevel,
+                  level);
     }
   }
 }
@@ -58,6 +59,7 @@ void RtpSourceObserver::GetRtpSources(
       domEntry.mSource = GetSourceFromKey(it.first);
       domEntry.mSourceType = GetTypeFromKey(it.first);
       domEntry.mTimestamp = entry->jitterAdjustedTimestamp;
+      domEntry.mRtpTimestamp = entry->rtpTimestamp;
       if (entry->hasAudioLevel) {
         domEntry.mAudioLevel.Construct(entry->ToLinearAudioLevel());
       }
@@ -130,9 +132,11 @@ void RtpSourceObserver::RtpSourceHistory::Prune(const int64_t aTimeNow) {
 
 void RtpSourceObserver::RtpSourceHistory::Insert(const int64_t aTimeNow,
                                                  const int64_t aTimestamp,
+                                                 const uint32_t aRtpTimestamp,
                                                  const bool aHasAudioLevel,
                                                  const uint8_t aAudioLevel) {
-  Insert(aTimeNow, aTimestamp).Update(aTimestamp, aHasAudioLevel, aAudioLevel);
+  Insert(aTimeNow, aTimestamp)
+      .Update(aTimestamp, aRtpTimestamp, aHasAudioLevel, aAudioLevel);
 }
 
 RtpSourceObserver::RtpSourceEntry& RtpSourceObserver::RtpSourceHistory::Insert(
diff --git a/media/webrtc/signaling/src/media-conduit/RtpSourceObserver.h b/media/webrtc/signaling/src/media-conduit/RtpSourceObserver.h
index 9bcbd5f0aa..99a4ed50a1 100644
--- a/media/webrtc/signaling/src/media-conduit/RtpSourceObserver.h
+++ b/media/webrtc/signaling/src/media-conduit/RtpSourceObserver.h
@@ -51,9 +51,10 @@ class RtpSourceObserver : public webrtc::RtpPacketObserver {
   // Note: these are pool allocated
   struct RtpSourceEntry {
     RtpSourceEntry() = default;
-    void Update(const int64_t aTimestamp, const bool aHasAudioLevel,
-                const uint8_t aAudioLevel) {
+    void Update(const int64_t aTimestamp, const uint32_t aRtpTimestamp,
+                const bool aHasAudioLevel, const uint8_t aAudioLevel) {
       jitterAdjustedTimestamp = aTimestamp;
+      rtpTimestamp = aRtpTimestamp;
       // Audio level range is 0 - 127 inclusive
       hasAudioLevel = aHasAudioLevel && !(aAudioLevel & 0x80);
       audioLevel = aAudioLevel;
@@ -63,6 +64,8 @@ class RtpSourceObserver : public webrtc::RtpPacketObserver {
     double ToLinearAudioLevel() const;
     // Time this information was received + jitter
     int64_t jitterAdjustedTimestamp = 0;
+    // The original RTP timestamp in the received packet
+    uint32_t rtpTimestamp = 0;
     bool hasAudioLevel = false;
     uint8_t audioLevel = 0;
   };
@@ -97,7 +100,8 @@ class RtpSourceObserver : public webrtc::RtpPacketObserver {
     const RtpSourceEntry* FindClosestNotAfter(int64_t aTime) const;
     // Inserts data into the history, may silently drop data if it is too old
     void Insert(const int64_t aTimeNow, const int64_t aTimestamp,
-                const bool aHasAudioLevel, const uint8_t aAudioLevel);
+                const uint32_t aRtpTimestamp, const bool aHasAudioLevel,
+                const uint8_t aAudioLevel);
     // Removes aged out from the jitter window
     void Prune(const int64_t aTimeNow);
     // Set Source
@@ -162,12 +166,11 @@ class RtpSourceObserver : public webrtc::RtpPacketObserver {
 
   // Testing only
   // Inserts additional csrc audio levels for mochitests
-  friend void InsertAudioLevelForContributingSource(RtpSourceObserver& observer,
-                                                    uint32_t aCsrcSource,
-                                                    int64_t aTimestamp,
-                                                    bool aHasAudioLevel,
-                                                    uint8_t aAudioLevel);
+  friend void InsertAudioLevelForContributingSource(
+      RtpSourceObserver& observer, const uint32_t aCsrcSource,
+      const int64_t aTimestamp, const uint32_t aRtpTimestamp,
+      const bool aHasAudioLevel, const uint8_t aAudioLevel);
 };
 }  // namespace mozilla
 #undef NG
-#endif  // AUDIOLEVELOBSERVER_H
\ No newline at end of file
+#endif  // AUDIOLEVELOBSERVER_H
diff --git a/media/webrtc/signaling/src/media-conduit/VideoConduit.cpp b/media/webrtc/signaling/src/media-conduit/VideoConduit.cpp
index 10c9033dac..dfef0155a7 100644
--- a/media/webrtc/signaling/src/media-conduit/VideoConduit.cpp
+++ b/media/webrtc/signaling/src/media-conduit/VideoConduit.cpp
@@ -2045,9 +2045,19 @@ MediaConduitErrorCode WebrtcVideoConduit::ReceivedRTCPPacket(const void* data,
     return kMediaConduitRTPProcessingFailed;
   }
 
+  // TODO(bug 1496533): We will need to keep separate timestamps for each SSRC,
+  // and for each SSRC we will need to keep a timestamp for SR and RR.
+  mLastRtcpReceived = Some(GetNow());
   return kMediaConduitNoError;
 }
 
+// TODO(bug 1496533): We will need to add a type (ie; SR or RR) param here, or
+// perhaps break this function into two functions, one for each type.
+Maybe<DOMHighResTimeStamp> WebrtcVideoConduit::LastRtcpReceived() const {
+  ASSERT_ON_THREAD(mStsThread);
+  return mLastRtcpReceived;
+}
+
 MediaConduitErrorCode WebrtcVideoConduit::StopTransmitting() {
   MOZ_ASSERT(NS_IsMainThread());
   MutexAutoLock lock(mMutex);
diff --git a/media/webrtc/signaling/src/media-conduit/VideoConduit.h b/media/webrtc/signaling/src/media-conduit/VideoConduit.h
index 394b5559fa..cdca88636a 100644
--- a/media/webrtc/signaling/src/media-conduit/VideoConduit.h
+++ b/media/webrtc/signaling/src/media-conduit/VideoConduit.h
@@ -102,6 +102,8 @@ class WebrtcVideoConduit
    * feed in received RTCP Frames to the VideoEngine for decoding
    */
   MediaConduitErrorCode ReceivedRTCPPacket(const void* data, int len) override;
+  Maybe<DOMHighResTimeStamp> LastRtcpReceived() const override;
+  DOMHighResTimeStamp GetNow() const override { return mCall->GetNow(); }
 
   MediaConduitErrorCode StopTransmitting() override;
   MediaConduitErrorCode StartTransmitting() override;
@@ -625,6 +627,9 @@ class WebrtcVideoConduit
 
   // Main thread only
   std::string mPCHandle;
+
+  // Accessed only on mStsThread
+  Maybe<DOMHighResTimeStamp> mLastRtcpReceived;
 };
 }  // namespace mozilla
 
diff --git a/media/webrtc/signaling/src/media-conduit/WebrtcGmpVideoCodec.cpp b/media/webrtc/signaling/src/media-conduit/WebrtcGmpVideoCodec.cpp
index 11500164b8..5993d2f488 100644
--- a/media/webrtc/signaling/src/media-conduit/WebrtcGmpVideoCodec.cpp
+++ b/media/webrtc/signaling/src/media-conduit/WebrtcGmpVideoCodec.cpp
@@ -6,37 +6,23 @@
 
 #include <vector>
 
+#include "gmp-video-frame-i420.h"
+#include "gmp-video-frame-encoded.h"
+#include "GMPLog.h"
+#include "MainThreadUtils.h"
 #include "mozilla/CheckedInt.h"
 #include "mozilla/EndianUtils.h"
 #include "mozilla/IntegerPrintfMacros.h"
 #include "mozilla/Move.h"
 #include "mozilla/SyncRunnable.h"
-#include "VideoConduit.h"
-#include "AudioConduit.h"
-#include "runnable_utils.h"
-
 #include "nsServiceManagerUtils.h"
-#include "GMPVideoDecoderProxy.h"
-#include "GMPVideoEncoderProxy.h"
-#include "MainThreadUtils.h"
-
-#include "gmp-video-host.h"
-#include "gmp-video-frame-i420.h"
-#include "gmp-video-frame-encoded.h"
+#include "runnable_utils.h"
+#include "VideoConduit.h"
 #include "webrtc/common_video/include/video_frame_buffer.h"
 #include "webrtc/rtc_base/bind.h"
 
 namespace mozilla {
 
-#ifdef LOG
-#  undef LOG
-#endif
-
-extern mozilla::LogModule* GetGMPLog();
-
-#define LOGD(msg) MOZ_LOG(GetGMPLog(), mozilla::LogLevel::Debug, msg)
-#define LOG(level, msg) MOZ_LOG(GetGMPLog(), (level), msg)
-
 WebrtcGmpPCHandleSetter::WebrtcGmpPCHandleSetter(const std::string& aPCHandle) {
   if (!NS_IsMainThread()) {
     MOZ_ASSERT(false, "WebrtcGmpPCHandleSetter can only be used on main");
@@ -214,7 +200,7 @@ void WebrtcGmpVideoEncoder::InitEncode_g(
   nsresult rv = aThis->mMPS->GetGMPVideoEncoder(
       nullptr, &tags, NS_LITERAL_CSTRING(""), std::move(callback));
   if (NS_WARN_IF(NS_FAILED(rv))) {
-    LOGD(("GMP Encode: GetGMPVideoEncoder failed"));
+    GMP_LOG_DEBUG("GMP Encode: GetGMPVideoEncoder failed");
     aThis->Close_g();
     aInitDone->Dispatch(WEBRTC_VIDEO_CODEC_ERROR,
                         "GMP Encode: GetGMPVideoEncoder failed");
@@ -341,7 +327,7 @@ void WebrtcGmpVideoEncoder::Encode_g(
     std::vector<webrtc::FrameType> aFrameTypes) {
   if (!aEncoder->mGMP) {
     // destroyed via Terminate(), failed to init, or just not initted yet
-    LOGD(("GMP Encode: not initted yet"));
+    GMP_LOG_DEBUG("GMP Encode: not initted yet");
     return;
   }
   MOZ_ASSERT(aEncoder->mHost);
@@ -350,9 +336,9 @@ void WebrtcGmpVideoEncoder::Encode_g(
           aEncoder->mCodecParams.mWidth ||
       static_cast<uint32_t>(aInputImage.height()) !=
           aEncoder->mCodecParams.mHeight) {
-    LOGD(("GMP Encode: resolution change from %ux%u to %dx%d",
-          aEncoder->mCodecParams.mWidth, aEncoder->mCodecParams.mHeight,
-          aInputImage.width(), aInputImage.height()));
+    GMP_LOG_DEBUG("GMP Encode: resolution change from %ux%u to %dx%d",
+                  aEncoder->mCodecParams.mWidth, aEncoder->mCodecParams.mHeight,
+                  aInputImage.width(), aInputImage.height());
 
     RefPtr<GmpInitDoneRunnable> initDone(
         new GmpInitDoneRunnable(aEncoder->mPCHandle));
@@ -367,7 +353,7 @@ void WebrtcGmpVideoEncoder::Encode_g(
   GMPVideoFrame* ftmp = nullptr;
   GMPErr err = aEncoder->mHost->CreateFrame(kGMPI420VideoFrame, &ftmp);
   if (err != GMPNoErr) {
-    LOGD(("GMP Encode: failed to create frame on host"));
+    GMP_LOG_DEBUG("GMP Encode: failed to create frame on host");
     return;
   }
   GMPUniquePtr<GMPVideoi420Frame> frame(static_cast<GMPVideoi420Frame*>(ftmp));
@@ -387,7 +373,7 @@ void WebrtcGmpVideoEncoder::Encode_g(
       input_image->DataV(), input_image->width(), input_image->height(),
       input_image->StrideY(), input_image->StrideU(), input_image->StrideV());
   if (err != GMPNoErr) {
-    LOGD(("GMP Encode: failed to create frame"));
+    GMP_LOG_DEBUG("GMP Encode: failed to create frame");
     return;
   }
   frame->SetTimestamp((aInputImage.timestamp() * 1000ll) /
@@ -409,18 +395,19 @@ void WebrtcGmpVideoEncoder::Encode_g(
 
     int32_t ret = WebrtcFrameTypeToGmpFrameType(*it, &ft);
     if (ret != WEBRTC_VIDEO_CODEC_OK) {
-      LOGD(("GMP Encode: failed to map webrtc frame type to gmp frame type"));
+      GMP_LOG_DEBUG(
+          "GMP Encode: failed to map webrtc frame type to gmp frame type");
       return;
     }
 
     gmp_frame_types.AppendElement(ft);
   }
 
-  LOGD(("GMP Encode: %llu", (aInputImage.timestamp() * 1000ll) / 90));
+  GMP_LOG_DEBUG("GMP Encode: %llu", (aInputImage.timestamp() * 1000ll) / 90);
   err = aEncoder->mGMP->Encode(std::move(frame), codecSpecificInfo,
                                gmp_frame_types);
   if (err != GMPNoErr) {
-    LOGD(("GMP Encode: failed to encode frame"));
+    GMP_LOG_DEBUG("GMP Encode: failed to encode frame");
   }
 }
 
@@ -439,7 +426,7 @@ void WebrtcGmpVideoEncoder::ReleaseGmp_g(
 }
 
 int32_t WebrtcGmpVideoEncoder::Shutdown() {
-  LOGD(("GMP Released:"));
+  GMP_LOG_DEBUG("GMP Released:");
   if (mGMPThread) {
     mGMPThread->Dispatch(WrapRunnableNM(&WebrtcGmpVideoEncoder::ReleaseGmp_g,
                                         RefPtr<WebrtcGmpVideoEncoder>(this)),
@@ -486,7 +473,7 @@ int32_t WebrtcGmpVideoEncoder::SetRates_g(RefPtr<WebrtcGmpVideoEncoder> aThis,
 
 // GMPVideoEncoderCallback virtual functions.
 void WebrtcGmpVideoEncoder::Terminated() {
-  LOGD(("GMP Encoder Terminated: %p", (void*)this));
+  GMP_LOG_DEBUG("GMP Encoder Terminated: %p", (void*)this);
 
   mGMP->Close();
   mGMP = nullptr;
@@ -504,9 +491,9 @@ void WebrtcGmpVideoEncoder::Encoded(
     GmpFrameTypeToWebrtcFrameType(aEncodedFrame->FrameType(), &ft);
     uint32_t timestamp = (aEncodedFrame->TimeStamp() * 90ll + 999) / 1000;
 
-    LOGD(("GMP Encoded: %" PRIu64 ", type %d, len %d",
-          aEncodedFrame->TimeStamp(), aEncodedFrame->BufferType(),
-          aEncodedFrame->Size()));
+    GMP_LOG_DEBUG("GMP Encoded: %" PRIu64 ", type %d, len %d",
+                  aEncodedFrame->TimeStamp(), aEncodedFrame->BufferType(),
+                  aEncodedFrame->Size());
 
     // Right now makes one Encoded() callback per unit
     // XXX convert to FragmentationHeader format (array of offsets and sizes
@@ -515,7 +502,7 @@ void WebrtcGmpVideoEncoder::Encoded(
     uint8_t* buffer = aEncodedFrame->Buffer();
 
     if (!buffer) {
-      LOG(LogLevel::Error, ("GMP plugin returned null buffer"));
+      GMP_LOG_ERROR("GMP plugin returned null buffer");
       return;
     }
 
@@ -539,8 +526,8 @@ void WebrtcGmpVideoEncoder::Encoded(
         break;
       default:
         // Really that it's not in the enum
-        LOG(LogLevel::Error, ("GMP plugin returned incorrect type (%d)",
-                              aEncodedFrame->BufferType()));
+        GMP_LOG_ERROR("GMP plugin returned incorrect type (%d)",
+                      aEncodedFrame->BufferType());
         // XXX Bug 1041232 - need a better API for interfacing to the
         // plugin so we can kill it here
         return;
@@ -606,9 +593,10 @@ void WebrtcGmpVideoEncoder::Encoded(
       if (size == 0 || buffer + size > end) {
         // XXX see above - should we kill the plugin for returning extra bytes?
         // Probably
-        LOG(LogLevel::Error, ("GMP plugin returned badly formatted encoded "
-                              "data: buffer=%p, size=%d, end=%p",
-                              buffer, size, end));
+        GMP_LOG_ERROR(
+            "GMP plugin returned badly formatted encoded "
+            "data: buffer=%p, size=%d, end=%p",
+            buffer, size, end);
         return;
       }
       // XXX optimize by making buffer an offset
@@ -620,7 +608,7 @@ void WebrtcGmpVideoEncoder::Encoded(
     }
     if (buffer != end) {
       // At most 3 bytes can be left over, depending on buffertype
-      LOGD(("GMP plugin returned %td extra bytes", end - buffer));
+      GMP_LOG_DEBUG("GMP plugin returned %td extra bytes", end - buffer);
     }
 
     size_t num_nals = nals.Length();
@@ -703,7 +691,7 @@ void WebrtcGmpVideoDecoder::InitDecode_g(
   nsresult rv = aThis->mMPS->GetGMPVideoDecoder(
       nullptr, &tags, NS_LITERAL_CSTRING(""), std::move(callback));
   if (NS_WARN_IF(NS_FAILED(rv))) {
-    LOGD(("GMP Decode: GetGMPVideoDecoder failed"));
+    GMP_LOG_DEBUG("GMP Decode: GetGMPVideoDecoder failed");
     aThis->Close_g();
     aInitDone->Dispatch(WEBRTC_VIDEO_CODEC_ERROR,
                         "GMP Decode: GetGMPVideoDecoder failed.");
@@ -753,8 +741,7 @@ int32_t WebrtcGmpVideoDecoder::GmpInitDone(GMPVideoDecoderProxy* aGMP,
   // now release any frames that got queued waiting for InitDone
   if (!mQueuedFrames.IsEmpty()) {
     // So we're safe to call Decode_g(), which asserts it's empty
-    nsTArray<UniquePtr<GMPDecodeData>> temp;
-    temp.SwapElements(mQueuedFrames);
+    nsTArray<UniquePtr<GMPDecodeData>> temp = std::move(mQueuedFrames);
     for (auto& queued : temp) {
       Decode_g(RefPtr<WebrtcGmpVideoDecoder>(this), std::move(queued));
     }
@@ -767,9 +754,8 @@ int32_t WebrtcGmpVideoDecoder::GmpInitDone(GMPVideoDecoderProxy* aGMP,
   // happens to arrive for other reasons. Bug 1492852 tracks implementing a
   // proper solution.
   if (mDecoderStatus != GMPNoErr) {
-    LOG(LogLevel::Error,
-        ("%s: Decoder status is bad (%u)!", __PRETTY_FUNCTION__,
-         static_cast<unsigned>(mDecoderStatus)));
+    GMP_LOG_ERROR("%s: Decoder status is bad (%u)!", __PRETTY_FUNCTION__,
+                  static_cast<unsigned>(mDecoderStatus));
     return WEBRTC_VIDEO_CODEC_ERROR;
   }
 
@@ -814,9 +800,8 @@ int32_t WebrtcGmpVideoDecoder::Decode(
                        NS_DISPATCH_NORMAL);
 
   if (mDecoderStatus != GMPNoErr) {
-    LOG(LogLevel::Error,
-        ("%s: Decoder status is bad (%u)!", __PRETTY_FUNCTION__,
-         static_cast<unsigned>(mDecoderStatus)));
+    GMP_LOG_ERROR("%s: Decoder status is bad (%u)!", __PRETTY_FUNCTION__,
+                  static_cast<unsigned>(mDecoderStatus));
     return WEBRTC_VIDEO_CODEC_ERROR;
   }
 
@@ -833,7 +818,7 @@ void WebrtcGmpVideoDecoder::Decode_g(const RefPtr<WebrtcGmpVideoDecoder>& aThis,
       return;
     }
     // destroyed via Terminate(), failed to init, or just not initted yet
-    LOGD(("GMP Decode: not initted yet"));
+    GMP_LOG_DEBUG("GMP Decode: not initted yet");
 
     aThis->mDecoderStatus = GMPDecodeErr;
     return;
@@ -845,8 +830,8 @@ void WebrtcGmpVideoDecoder::Decode_g(const RefPtr<WebrtcGmpVideoDecoder>& aThis,
   GMPVideoFrame* ftmp = nullptr;
   GMPErr err = aThis->mHost->CreateFrame(kGMPEncodedVideoFrame, &ftmp);
   if (err != GMPNoErr) {
-    LOG(LogLevel::Error, ("%s: CreateFrame failed (%u)!", __PRETTY_FUNCTION__,
-                          static_cast<unsigned>(err)));
+    GMP_LOG_ERROR("%s: CreateFrame failed (%u)!", __PRETTY_FUNCTION__,
+                  static_cast<unsigned>(err));
     aThis->mDecoderStatus = err;
     return;
   }
@@ -855,8 +840,8 @@ void WebrtcGmpVideoDecoder::Decode_g(const RefPtr<WebrtcGmpVideoDecoder>& aThis,
       static_cast<GMPVideoEncodedFrame*>(ftmp));
   err = frame->CreateEmptyFrame(aDecodeData->mImage._length);
   if (err != GMPNoErr) {
-    LOG(LogLevel::Error, ("%s: CreateEmptyFrame failed (%u)!",
-                          __PRETTY_FUNCTION__, static_cast<unsigned>(err)));
+    GMP_LOG_ERROR("%s: CreateEmptyFrame failed (%u)!", __PRETTY_FUNCTION__,
+                  static_cast<unsigned>(err));
     aThis->mDecoderStatus = err;
     return;
   }
@@ -880,8 +865,8 @@ void WebrtcGmpVideoDecoder::Decode_g(const RefPtr<WebrtcGmpVideoDecoder>& aThis,
   int32_t ret =
       WebrtcFrameTypeToGmpFrameType(aDecodeData->mImage._frameType, &ft);
   if (ret != WEBRTC_VIDEO_CODEC_OK) {
-    LOG(LogLevel::Error, ("%s: WebrtcFrameTypeToGmpFrameType failed (%u)!",
-                          __PRETTY_FUNCTION__, static_cast<unsigned>(ret)));
+    GMP_LOG_ERROR("%s: WebrtcFrameTypeToGmpFrameType failed (%u)!",
+                  __PRETTY_FUNCTION__, static_cast<unsigned>(ret));
     aThis->mDecoderStatus = GMPDecodeErr;
     return;
   }
@@ -895,15 +880,16 @@ void WebrtcGmpVideoDecoder::Decode_g(const RefPtr<WebrtcGmpVideoDecoder>& aThis,
   codecSpecificInfo.AppendElements((uint8_t*)&info,
                                    sizeof(GMPCodecSpecificInfo));
 
-  LOGD(("GMP Decode: %" PRIu64 ", len %zu%s", frame->TimeStamp(),
-        aDecodeData->mImage._length, ft == kGMPKeyFrame ? ", KeyFrame" : ""));
+  GMP_LOG_DEBUG("GMP Decode: %" PRIu64 ", len %zu%s", frame->TimeStamp(),
+                aDecodeData->mImage._length,
+                ft == kGMPKeyFrame ? ", KeyFrame" : "");
 
   nsresult rv =
       aThis->mGMP->Decode(std::move(frame), aDecodeData->mMissingFrames,
                           codecSpecificInfo, aDecodeData->mRenderTimeMs);
   if (NS_FAILED(rv)) {
-    LOG(LogLevel::Error, ("%s: Decode failed (rv=%u)!", __PRETTY_FUNCTION__,
-                          static_cast<unsigned>(rv)));
+    GMP_LOG_ERROR("%s: Decode failed (rv=%u)!", __PRETTY_FUNCTION__,
+                  static_cast<unsigned>(rv));
     aThis->mDecoderStatus = GMPDecodeErr;
     return;
   }
@@ -926,7 +912,7 @@ void WebrtcGmpVideoDecoder::ReleaseGmp_g(
 }
 
 int32_t WebrtcGmpVideoDecoder::ReleaseGmp() {
-  LOGD(("GMP Released:"));
+  GMP_LOG_DEBUG("GMP Released:");
   RegisterDecodeCompleteCallback(nullptr);
 
   if (mGMPThread) {
@@ -938,7 +924,7 @@ int32_t WebrtcGmpVideoDecoder::ReleaseGmp() {
 }
 
 void WebrtcGmpVideoDecoder::Terminated() {
-  LOGD(("GMP Decoder Terminated: %p", (void*)this));
+  GMP_LOG_DEBUG("GMP Decoder Terminated: %p", (void*)this);
 
   mGMP->Close();
   mGMP = nullptr;
@@ -997,7 +983,7 @@ void WebrtcGmpVideoDecoder::Decoded(GMPVideoi420Frame* aDecodedFrame) {
       image.set_timestamp((aDecodedFrame->Timestamp() * 90ll + 999) /
                           1000);  // round up
 
-      LOGD(("GMP Decoded: %" PRIu64, aDecodedFrame->Timestamp()));
+      GMP_LOG_DEBUG("GMP Decoded: %" PRIu64, aDecodedFrame->Timestamp());
       mCallback->Decoded(image);
     }
   }
diff --git a/media/webrtc/signaling/src/media-conduit/moz.build b/media/webrtc/signaling/src/media-conduit/moz.build
index 0e9f0cbb00..94eb9e9fa0 100644
--- a/media/webrtc/signaling/src/media-conduit/moz.build
+++ b/media/webrtc/signaling/src/media-conduit/moz.build
@@ -5,6 +5,7 @@ include('../../../webrtc.mozbuild')
 
 LOCAL_INCLUDES += [
     '!/ipc/ipdl/_ipdlheaders',
+    '/dom/media/gmp', # for GMPLog.h
     '/ipc/chromium/src',
     '/media/libyuv/libyuv/include',
     '/media/mtransport',
diff --git a/media/webrtc/signaling/src/mediapipeline/MediaPipeline.cpp b/media/webrtc/signaling/src/mediapipeline/MediaPipeline.cpp
index 825dd6b100..78b6fa927f 100644
--- a/media/webrtc/signaling/src/mediapipeline/MediaPipeline.cpp
+++ b/media/webrtc/signaling/src/mediapipeline/MediaPipeline.cpp
@@ -712,11 +712,11 @@ class MediaPipelineTransmit::PipelineListener
         ->SendVideoFrame(aVideoFrame);
   }
 
+  void SetTrackEnabled(MediaStreamTrack* aTrack, bool aEnabled);
+
   // Implement MediaTrackListener
   void NotifyQueuedChanges(MediaTrackGraph* aGraph, TrackTime aOffset,
                            const MediaSegment& aQueuedMedia) override;
-  void NotifyEnabledStateChanged(MediaTrackGraph* aGraph,
-                                 bool aEnabled) override;
 
   // Implement DirectMediaTrackListener
   void NotifyRealtimeTrackData(MediaTrackGraph* aGraph, TrackTime aOffset,
@@ -741,6 +741,29 @@ class MediaPipelineTransmit::PipelineListener
   bool mDirectConnect;
 };
 
+// MediaStreamTrackConsumer inherits from SupportsWeakPtr, which is
+// main-thread-only.
+class MediaPipelineTransmit::PipelineListenerTrackConsumer
+    : public MediaStreamTrackConsumer {
+  virtual ~PipelineListenerTrackConsumer() { MOZ_ASSERT(NS_IsMainThread()); }
+
+  const RefPtr<PipelineListener> mListener;
+
+ public:
+  NS_INLINE_DECL_REFCOUNTING(PipelineListenerTrackConsumer)
+
+  explicit PipelineListenerTrackConsumer(RefPtr<PipelineListener> aListener)
+      : mListener(std::move(aListener)) {
+    MOZ_ASSERT(NS_IsMainThread());
+  }
+
+  // Implement MediaStreamTrackConsumer
+  void NotifyEnabledChanged(MediaStreamTrack* aTrack, bool aEnabled) override {
+    MOZ_ASSERT(NS_IsMainThread());
+    mListener->SetTrackEnabled(aTrack, aEnabled);
+  }
+};
+
 // Implements VideoConverterListener for MediaPipeline.
 //
 // We pass converted frames on to MediaPipelineTransmit::PipelineListener
@@ -787,6 +810,10 @@ MediaPipelineTransmit::MediaPipelineTransmit(
                     std::move(aConduit)),
       mIsVideo(aIsVideo),
       mListener(new PipelineListener(mConduit)),
+      mTrackConsumer(
+          MakeAndAddRef<nsMainThreadPtrHolder<PipelineListenerTrackConsumer>>(
+              "MediaPipelineTransmit::mTrackConsumer",
+              MakeAndAddRef<PipelineListenerTrackConsumer>(mListener))),
       mFeeder(aIsVideo ? MakeAndAddRef<VideoFrameFeeder>(mListener)
                        : nullptr),  // For video we send frames to an
                                     // async VideoFrameConverter that
@@ -841,26 +868,25 @@ void MediaPipelineTransmit::SetDescription() {
       NS_DISPATCH_NORMAL);
 }
 
-void MediaPipelineTransmit::Stop() {
+RefPtr<GenericPromise> MediaPipelineTransmit::Stop() {
   ASSERT_ON_THREAD(mMainThread);
 
-  if (!mDomTrack || !mTransmitting) {
-    return;
+  if (!mTransmitting) {
+    return GenericPromise::CreateAndResolve(true, __func__);
+  }
+
+  if (!mSendTrack) {
+    return GenericPromise::CreateAndResolve(true, __func__);
   }
 
   mTransmitting = false;
-
-  if (mDomTrack->AsAudioStreamTrack()) {
-    mDomTrack->RemoveDirectListener(mListener);
-    mDomTrack->RemoveListener(mListener);
-  } else if (mDomTrack->AsVideoStreamTrack()) {
-    mDomTrack->RemoveDirectListener(mListener);
-    mDomTrack->RemoveListener(mListener);
-  } else {
-    MOZ_ASSERT(false, "Unknown track type");
-  }
-
   mConduit->StopTransmitting();
+
+  mSendTrack->Suspend();
+  if (mSendTrack->mType == MediaSegment::VIDEO) {
+    mSendTrack->RemoveDirectListener(mListener);
+  }
+  return mSendTrack->RemoveListener(mListener);
 }
 
 bool MediaPipelineTransmit::Transmitting() const {
@@ -872,12 +898,15 @@ bool MediaPipelineTransmit::Transmitting() const {
 void MediaPipelineTransmit::Start() {
   ASSERT_ON_THREAD(mMainThread);
 
-  if (!mDomTrack || mTransmitting) {
+  if (mTransmitting) {
+    return;
+  }
+
+  if (!mSendTrack) {
     return;
   }
 
   mTransmitting = true;
-
   mConduit->StartTransmitting();
 
   // TODO(ekr@rtfm.com): Check for errors
@@ -886,30 +915,12 @@ void MediaPipelineTransmit::Start() {
       ("Attaching pipeline to track %p conduit type=%s", this,
        (mConduit->type() == MediaSessionConduit::AUDIO ? "audio" : "video")));
 
-#if !defined(MOZILLA_EXTERNAL_LINKAGE)
-  // With full duplex we don't risk having audio come in late to the MTG
-  // so we won't need a direct listener.
-  const bool enableDirectListener =
-      !Preferences::GetBool("media.navigator.audio.full_duplex", false);
-#else
-  const bool enableDirectListener = true;
-#endif
+  mSendTrack->Resume();
 
-  if (mDomTrack->AsAudioStreamTrack()) {
-    if (enableDirectListener) {
-      // Register the Listener directly with the source if we can.
-      // We also register it as a non-direct listener so we fall back to that
-      // if installing the direct listener fails. As a direct listener we get
-      // access to direct unqueued (and not resampled) data.
-      mDomTrack->AddDirectListener(mListener);
-    }
-    mDomTrack->AddListener(mListener);
-  } else if (mDomTrack->AsVideoStreamTrack()) {
-    mDomTrack->AddDirectListener(mListener);
-    mDomTrack->AddListener(mListener);
-  } else {
-    MOZ_ASSERT(false, "Unknown track type");
+  if (mSendTrack->mType == MediaSegment::VIDEO) {
+    mSendTrack->AddDirectListener(mListener);
   }
+  mSendTrack->AddListener(mListener);
 }
 
 bool MediaPipelineTransmit::IsVideo() const { return mIsVideo; }
@@ -948,7 +959,19 @@ void MediaPipelineTransmit::UpdateSinkIdentity_m(
 
 void MediaPipelineTransmit::DetachMedia() {
   ASSERT_ON_THREAD(mMainThread);
-  mDomTrack = nullptr;
+  MOZ_ASSERT(!mTransmitting);
+  if (mDomTrack) {
+    mDomTrack->RemoveConsumer(mTrackConsumer);
+    mDomTrack = nullptr;
+  }
+  if (mSendPort) {
+    mSendPort->Destroy();
+    mSendPort = nullptr;
+  }
+  if (mSendTrack) {
+    mSendTrack->Destroy();
+    mSendTrack = nullptr;
+  }
   // Let the listener be destroyed with the pipeline (or later).
 }
 
@@ -960,7 +983,8 @@ void MediaPipelineTransmit::TransportReady_s() {
 }
 
 nsresult MediaPipelineTransmit::SetTrack(RefPtr<MediaStreamTrack> aDomTrack) {
-  // MainThread, checked in calls we make
+  MOZ_ASSERT(NS_IsMainThread());
+
   if (aDomTrack) {
     nsString nsTrackId;
     aDomTrack->GetId(nsTrackId);
@@ -972,18 +996,71 @@ nsresult MediaPipelineTransmit::SetTrack(RefPtr<MediaStreamTrack> aDomTrack) {
          (mConduit->type() == MediaSessionConduit::AUDIO ? "audio" : "video")));
   }
 
-  RefPtr<dom::MediaStreamTrack> oldTrack = mDomTrack;
-  bool wasTransmitting = oldTrack && mTransmitting;
-  Stop();
+  if (mDomTrack) {
+    mDomTrack->RemoveConsumer(mTrackConsumer);
+  }
+  if (mSendPort) {
+    mSendPort->Destroy();
+    mSendPort = nullptr;
+  }
+
+  bool wasTransmitting = false;
+  if (aDomTrack && mDomTrack && !aDomTrack->Ended() && !mDomTrack->Ended() &&
+      aDomTrack->Graph() != mDomTrack->Graph() && mSendTrack) {
+    // Recreate the send track if the new stream resides in different MTG.
+    // Stopping and re-starting will result in removing and re-adding the
+    // listener BUT in different threads, since tracks belong to different MTGs.
+    // This can create tread races so we wait here for the stop to happen
+    // before re-starting. Please note that start should happen at the end of
+    // the method after the mSendTrack replace bellow. Since we dispatch the
+    // result of the promise to the next event of the same thread, it is
+    // guarantee the start will be executed after this method has finished.
+    wasTransmitting = mTransmitting;
+    RefPtr<MediaPipelineTransmit> self = this;
+    Stop()->Then(
+        GetMainThreadSerialEventTarget(), __func__,
+        [wasTransmitting, self](bool) {
+          if (wasTransmitting) {
+            self->Start();
+          }
+        },
+        [](nsresult aRv) { MOZ_CRASH("Never get here!"); });
+    mSendTrack->Destroy();
+    mSendTrack = nullptr;
+  }
+
   mDomTrack = std::move(aDomTrack);
   SetDescription();
 
-  if (wasTransmitting) {
-    Start();
+  if (mDomTrack) {
+    if (!mDomTrack->Ended()) {
+      if (!mSendTrack) {
+        // Create the send track when the first live track is set or when the
+        // new track resides in different MTG.
+        SetSendTrack(mDomTrack->Graph()->CreateForwardedInputTrack(
+            mDomTrack->GetTrack()->mType));
+      }
+      mSendPort = mSendTrack->AllocateInputPort(mDomTrack->GetTrack());
+    }
+    mDomTrack->AddConsumer(mTrackConsumer);
+    if (mConverter) {
+      mConverter->SetTrackEnabled(mDomTrack->Enabled());
+    }
   }
+
   return NS_OK;
 }
 
+void MediaPipelineTransmit::SetSendTrack(
+    RefPtr<ProcessedMediaTrack> aSendTrack) {
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(!mTransmitting);
+  MOZ_ASSERT(!mSendTrack);
+  mSendTrack = std::move(aSendTrack);
+  mSendTrack->QueueSetAutoend(false);
+  mSendTrack->Suspend();  // Suspended while not transmitting.
+}
+
 nsresult MediaPipeline::PipelineTransport::SendRtpPacket(const uint8_t* aData,
                                                          size_t aLen) {
   MediaPacket packet;
@@ -1099,11 +1176,13 @@ void MediaPipelineTransmit::PipelineListener::NotifyQueuedChanges(
   NewData(aQueuedMedia, rate);
 }
 
-void MediaPipelineTransmit::PipelineListener::NotifyEnabledStateChanged(
-    MediaTrackGraph* aGraph, bool aEnabled) {
+void MediaPipelineTransmit::PipelineListener::SetTrackEnabled(
+    MediaStreamTrack* aTrack, bool aEnabled) {
+  MOZ_ASSERT(NS_IsMainThread());
   if (mConduit->type() != MediaSessionConduit::VIDEO) {
     return;
   }
+
   MOZ_ASSERT(mConverter);
   mConverter->SetTrackEnabled(aEnabled);
 }
@@ -1477,11 +1556,12 @@ void MediaPipelineReceiveAudio::Start() {
   }
 }
 
-void MediaPipelineReceiveAudio::Stop() {
+RefPtr<GenericPromise> MediaPipelineReceiveAudio::Stop() {
   if (mListener) {
     mListener->RemoveSelf();
   }
   mConduit->StopReceiving();
+  return GenericPromise::CreateAndResolve(true, __func__);
 }
 
 void MediaPipelineReceiveAudio::OnRtpPacketReceived() {
@@ -1652,11 +1732,12 @@ void MediaPipelineReceiveVideo::Start() {
   }
 }
 
-void MediaPipelineReceiveVideo::Stop() {
+RefPtr<GenericPromise> MediaPipelineReceiveVideo::Stop() {
   if (mListener) {
     mListener->RemoveSelf();
   }
   mConduit->StopReceiving();
+  return GenericPromise::CreateAndResolve(true, __func__);
 }
 
 void MediaPipelineReceiveVideo::OnRtpPacketReceived() {
@@ -1665,14 +1746,14 @@ void MediaPipelineReceiveVideo::OnRtpPacketReceived() {
   }
 }
 
-DOMHighResTimeStamp MediaPipeline::GetNow() {
-  return webrtc::Clock::GetRealTimeClock()->TimeInMilliseconds();
+DOMHighResTimeStamp MediaPipeline::GetNow() const {
+  return Conduit()->GetNow();
 }
 
 DOMHighResTimeStamp MediaPipeline::RtpCSRCStats::GetExpiryFromTime(
     const DOMHighResTimeStamp aTime) {
   // DOMHighResTimeStamp is a unit measured in ms
-  return aTime - EXPIRY_TIME_MILLISECONDS;
+  return aTime + EXPIRY_TIME_MILLISECONDS;
 }
 
 MediaPipeline::RtpCSRCStats::RtpCSRCStats(const uint32_t aCsrc,
diff --git a/media/webrtc/signaling/src/mediapipeline/MediaPipeline.h b/media/webrtc/signaling/src/mediapipeline/MediaPipeline.h
index a01fed0e33..ee475c4535 100644
--- a/media/webrtc/signaling/src/mediapipeline/MediaPipeline.h
+++ b/media/webrtc/signaling/src/mediapipeline/MediaPipeline.h
@@ -31,10 +31,13 @@
 class nsIPrincipal;
 
 namespace mozilla {
+class AudioProxyThread;
+class MediaInputPort;
 class MediaPipelineFilter;
 class MediaTransportHandler;
 class PeerIdentity;
-class AudioProxyThread;
+class ProcessedMediaTrack;
+class SourceMediaTrack;
 class VideoFrameConverter;
 
 namespace dom {
@@ -42,8 +45,6 @@ class MediaStreamTrack;
 struct RTCRTPContributingSourceStats;
 }  // namespace dom
 
-class SourceMediaTrack;
-
 // A class that represents the pipeline of audio and video
 // The dataflow looks like:
 //
@@ -86,7 +87,7 @@ class MediaPipeline : public sigslot::has_slots<> {
                 RefPtr<MediaSessionConduit> aConduit);
 
   virtual void Start() = 0;
-  virtual void Stop() = 0;
+  virtual RefPtr<GenericPromise> Stop() = 0;
   virtual void DetachMedia() {}
 
   void SetLevel(size_t aLevel) { mLevel = aLevel; }
@@ -156,6 +157,8 @@ class MediaPipeline : public sigslot::has_slots<> {
   int32_t RtpPacketsReceived() const { return mRtpPacketsReceived; }
   int64_t RtpBytesReceived() const { return mRtpBytesReceived; }
   int32_t RtcpPacketsReceived() const { return mRtcpPacketsReceived; }
+  // Gets the current time as a DOMHighResTimeStamp
+  DOMHighResTimeStamp GetNow() const;
 
   MediaSessionConduit* Conduit() const { return mConduit; }
 
@@ -260,9 +263,6 @@ class MediaPipeline : public sigslot::has_slots<> {
   UniquePtr<PacketDumper> mPacketDumper;
 
  private:
-  // Gets the current time as a DOMHighResTimeStamp
-  static DOMHighResTimeStamp GetNow();
-
   bool IsRtp(const unsigned char* aData, size_t aLen) const;
   // Must be called on the STS thread.  Must be called after DetachMedia().
   void DetachTransport_s();
@@ -282,7 +282,7 @@ class MediaPipelineTransmit : public MediaPipeline {
   bool Transmitting() const;
 
   void Start() override;
-  void Stop() override;
+  RefPtr<GenericPromise> Stop() override;
 
   // written and used from MainThread
   bool IsVideo() const override;
@@ -300,14 +300,15 @@ class MediaPipelineTransmit : public MediaPipeline {
   // Override MediaPipeline::TransportReady_s.
   void TransportReady_s() override;
 
-  // Replace a track with a different one
-  // In non-compliance with the likely final spec, allow the new
-  // track to be part of a different stream (since we don't support
-  // multiple tracks of a type in a stream yet).  bug 1056650
-  virtual nsresult SetTrack(RefPtr<dom::MediaStreamTrack> aDomTrack);
+  // Replace a track with a different one.
+  nsresult SetTrack(RefPtr<dom::MediaStreamTrack> aDomTrack);
+
+  // Set the track whose data we will transmit. For internal and test use. */
+  void SetSendTrack(RefPtr<ProcessedMediaTrack> aSendTrack);
 
   // Separate classes to allow ref counting
   class PipelineListener;
+  class PipelineListenerTrackConsumer;
   class VideoFrameFeeder;
 
  protected:
@@ -318,10 +319,18 @@ class MediaPipelineTransmit : public MediaPipeline {
  private:
   const bool mIsVideo;
   const RefPtr<PipelineListener> mListener;
+  // Listens for changes in enabled state on the attached MediaStreamTrack, and
+  // notifies mListener.
+  const nsMainThreadPtrHandle<PipelineListenerTrackConsumer> mTrackConsumer;
   const RefPtr<VideoFrameFeeder> mFeeder;
   RefPtr<AudioProxyThread> mAudioProcessing;
   RefPtr<VideoFrameConverter> mConverter;
   RefPtr<dom::MediaStreamTrack> mDomTrack;
+  // Input port connecting mDomTrack's MediaTrack to mSendTrack.
+  RefPtr<MediaInputPort> mSendPort;
+  // MediaTrack that we send over the network. This allows changing mDomTrack.
+  RefPtr<ProcessedMediaTrack> mSendTrack;
+  // True if we're actively transmitting data to the network. Main thread only.
   bool mTransmitting;
 };
 
@@ -359,7 +368,7 @@ class MediaPipelineReceiveAudio : public MediaPipelineReceive {
   void MakePrincipalPrivate_s() override;
 
   void Start() override;
-  void Stop() override;
+  RefPtr<GenericPromise> Stop() override;
 
   void OnRtpPacketReceived() override;
 
@@ -390,7 +399,7 @@ class MediaPipelineReceiveVideo : public MediaPipelineReceive {
   void MakePrincipalPrivate_s() override;
 
   void Start() override;
-  void Stop() override;
+  RefPtr<GenericPromise> Stop() override;
 
   void OnRtpPacketReceived() override;
 
diff --git a/media/webrtc/signaling/src/peerconnection/MediaTransportHandler.cpp b/media/webrtc/signaling/src/peerconnection/MediaTransportHandler.cpp
index 33cd7a0167..0edd8424a7 100644
--- a/media/webrtc/signaling/src/peerconnection/MediaTransportHandler.cpp
+++ b/media/webrtc/signaling/src/peerconnection/MediaTransportHandler.cpp
@@ -111,9 +111,8 @@ class MediaTransportHandlerSTS : public MediaTransportHandler,
   void SendPacket(const std::string& aTransportId,
                   MediaPacket&& aPacket) override;
 
-  RefPtr<StatsPromise> GetIceStats(
-      const std::string& aTransportId, DOMHighResTimeStamp aNow,
-      std::unique_ptr<dom::RTCStatsReportInternal>&& aReport) override;
+  RefPtr<dom::RTCStatsPromise> GetIceStats(const std::string& aTransportId,
+                                           DOMHighResTimeStamp aNow) override;
 
  private:
   RefPtr<TransportFlow> CreateTransportFlow(const std::string& aTransportId,
@@ -152,7 +151,7 @@ class MediaTransportHandlerSTS : public MediaTransportHandler,
   RefPtr<TransportFlow> GetTransportFlow(const std::string& aTransportId,
                                          bool aIsRtcp) const;
   void GetIceStats(const NrIceMediaStream& aStream, DOMHighResTimeStamp aNow,
-                   dom::RTCStatsReportInternal* aReport) const;
+                   dom::RTCStatsCollection* aStats) const;
 
   virtual ~MediaTransportHandlerSTS() = default;
   nsCOMPtr<nsISerialEventTarget> mStsThread;
@@ -160,6 +159,8 @@ class MediaTransportHandlerSTS : public MediaTransportHandler,
   RefPtr<NrIceResolver> mDNSResolver;
   std::map<std::string, Transport> mTransports;
   bool mObfuscateHostAddresses = false;
+  uint32_t minDtlsVersion = 0;
+  uint32_t maxDtlsVersion = 0;
 
   std::set<std::string> mSignaledAddresses;
 
@@ -427,6 +428,13 @@ nsresult MediaTransportHandlerSTS::CreateIceCtx(
                                               __func__);
         }
 
+        // We are reading these here, because when we setup the DTLS transport
+        // we are on the wrong thread to read prefs
+        minDtlsVersion =
+            Preferences::GetUint("media.peerconnection.dtls.version.min");
+        maxDtlsVersion =
+            Preferences::GetUint("media.peerconnection.dtls.version.max");
+
         CSFLogDebug(LOGTAG, "%s done", __func__);
         return InitPromise::CreateAndResolve(true, __func__);
       });
@@ -927,22 +935,21 @@ void MediaTransportHandler::OnRtcpStateChange(const std::string& aTransportId,
   SignalRtcpStateChange(aTransportId, aState);
 }
 
-RefPtr<MediaTransportHandler::StatsPromise>
-MediaTransportHandlerSTS::GetIceStats(
-    const std::string& aTransportId, DOMHighResTimeStamp aNow,
-    std::unique_ptr<dom::RTCStatsReportInternal>&& aReport) {
+RefPtr<dom::RTCStatsPromise> MediaTransportHandlerSTS::GetIceStats(
+    const std::string& aTransportId, DOMHighResTimeStamp aNow) {
   return InvokeAsync(
       mStsThread, __func__,
-      [=, aReport = std::move(aReport),
-       self = RefPtr<MediaTransportHandlerSTS>(this)]() mutable {
+      [=, self = RefPtr<MediaTransportHandlerSTS>(this)]() {
+        UniquePtr<dom::RTCStatsCollection> stats(new dom::RTCStatsCollection);
         if (mIceCtx) {
           for (const auto& stream : mIceCtx->GetStreams()) {
             if (aTransportId.empty() || aTransportId == stream->GetId()) {
-              GetIceStats(*stream, aNow, aReport.get());
+              GetIceStats(*stream, aNow, stats.get());
             }
           }
         }
-        return StatsPromise::CreateAndResolve(std::move(aReport), __func__);
+        return dom::RTCStatsPromise::CreateAndResolve(std::move(stats),
+                                                      __func__);
       });
 }
 
@@ -1016,10 +1023,10 @@ void MediaTransportHandlerSTS::ExitPrivateMode() {
 static void ToRTCIceCandidateStats(
     const std::vector<NrIceCandidate>& candidates,
     dom::RTCStatsType candidateType, const nsString& transportId,
-    DOMHighResTimeStamp now, dom::RTCStatsReportInternal* report,
+    DOMHighResTimeStamp now, dom::RTCStatsCollection* stats,
     bool obfuscateHostAddresses,
     const std::set<std::string>& signaledAddresses) {
-  MOZ_ASSERT(report);
+  MOZ_ASSERT(stats);
   for (const auto& candidate : candidates) {
     dom::RTCIceCandidateStats cand;
     cand.mType.Construct(candidateType);
@@ -1054,15 +1061,14 @@ static void ToRTCIceCandidateStats(
     }
     cand.mProxied.Construct(NS_ConvertASCIItoUTF16(
         candidate.is_proxied ? "proxied" : "non-proxied"));
-    if (!report->mIceCandidateStats.Value().AppendElement(cand, fallible)) {
+    if (!stats->mIceCandidateStats.AppendElement(cand, fallible)) {
       // XXX(Bug 1632090) Instead of extending the array 1-by-1 (which might
       // involve multiple reallocations) and potentially crashing here,
       // SetCapacity could be called outside the loop once.
       mozalloc_handle_oom(0);
     }
     if (candidate.trickled) {
-      if (!report->mTrickledIceCandidateStats.Value().AppendElement(cand,
-                                                                    fallible)) {
+      if (!stats->mTrickledIceCandidateStats.AppendElement(cand, fallible)) {
         mozalloc_handle_oom(0);
       }
     }
@@ -1071,7 +1077,7 @@ static void ToRTCIceCandidateStats(
 
 void MediaTransportHandlerSTS::GetIceStats(
     const NrIceMediaStream& aStream, DOMHighResTimeStamp aNow,
-    dom::RTCStatsReportInternal* aReport) const {
+    dom::RTCStatsCollection* aStats) const {
   MOZ_ASSERT(mStsThread->IsOnCurrentThread());
 
   NS_ConvertASCIItoUTF16 transportId(aStream.GetId().c_str());
@@ -1110,7 +1116,7 @@ void MediaTransportHandlerSTS::GetIceStats(
     s.mLastPacketReceivedTimestamp.Construct(candPair.ms_since_last_recv);
     s.mState.Construct(dom::RTCStatsIceCandidatePairState(candPair.state));
     s.mComponentId.Construct(candPair.component_id);
-    if (!aReport->mIceCandidatePairStats.Value().AppendElement(s, fallible)) {
+    if (!aStats->mIceCandidatePairStats.AppendElement(s, fallible)) {
       // XXX(Bug 1632090) Instead of extending the array 1-by-1 (which might
       // involve multiple reallocations) and potentially crashing here,
       // SetCapacity could be called outside the loop once.
@@ -1121,11 +1127,11 @@ void MediaTransportHandlerSTS::GetIceStats(
   std::vector<NrIceCandidate> candidates;
   if (NS_SUCCEEDED(aStream.GetLocalCandidates(&candidates))) {
     ToRTCIceCandidateStats(candidates, dom::RTCStatsType::Local_candidate,
-                           transportId, aNow, aReport, mObfuscateHostAddresses,
+                           transportId, aNow, aStats, mObfuscateHostAddresses,
                            mSignaledAddresses);
     // add the local candidates unparsed string to a sequence
     for (const auto& candidate : candidates) {
-      if (!aReport->mRawLocalCandidates.Value().AppendElement(
+      if (!aStats->mRawLocalCandidates.AppendElement(
               NS_ConvertASCIItoUTF16(candidate.label.c_str()), fallible)) {
         // XXX(Bug 1632090) Instead of extending the array 1-by-1 (which might
         // involve multiple reallocations) and potentially crashing here,
@@ -1138,11 +1144,11 @@ void MediaTransportHandlerSTS::GetIceStats(
 
   if (NS_SUCCEEDED(aStream.GetRemoteCandidates(&candidates))) {
     ToRTCIceCandidateStats(candidates, dom::RTCStatsType::Remote_candidate,
-                           transportId, aNow, aReport, mObfuscateHostAddresses,
+                           transportId, aNow, aStats, mObfuscateHostAddresses,
                            mSignaledAddresses);
     // add the remote candidates unparsed string to a sequence
     for (const auto& candidate : candidates) {
-      if (!aReport->mRawRemoteCandidates.Value().AppendElement(
+      if (!aStats->mRawRemoteCandidates.AppendElement(
               NS_ConvertASCIItoUTF16(candidate.label.c_str()), fallible)) {
         // XXX(Bug 1632090) Instead of extending the array 1-by-1 (which might
         // involve multiple reallocations) and potentially crashing here,
@@ -1184,6 +1190,10 @@ RefPtr<TransportFlow> MediaTransportHandlerSTS::CreateTransportFlow(
 
   dtls->SetIdentity(aDtlsIdentity);
 
+  dtls->SetMinMaxVersion(
+      static_cast<TransportLayerDtls::Version>(minDtlsVersion),
+      static_cast<TransportLayerDtls::Version>(maxDtlsVersion));
+
   for (const auto& digest : aDigests) {
     rv = dtls->SetVerificationDigest(digest);
     if (NS_FAILED(rv)) {
diff --git a/media/webrtc/signaling/src/peerconnection/MediaTransportHandler.h b/media/webrtc/signaling/src/peerconnection/MediaTransportHandler.h
index 06df1e90fc..753cbbb24e 100644
--- a/media/webrtc/signaling/src/peerconnection/MediaTransportHandler.h
+++ b/media/webrtc/signaling/src/peerconnection/MediaTransportHandler.h
@@ -12,10 +12,10 @@
 #include "dtlsidentity.h"    // For DtlsDigest
 #include "mozilla/dom/RTCPeerConnectionBinding.h"
 #include "mozilla/dom/RTCConfigurationBinding.h"
-#include "nricectx.h"               // Need some enums
-#include "nsDOMNavigationTiming.h"  // DOMHighResTimeStamp
+#include "nricectx.h"  // Need some enums
 #include "signaling/src/common/CandidateInfo.h"
 #include "nr_socket_proxy_config.h"
+#include "RTCStatsReport.h"
 
 #include "nsString.h"
 
@@ -115,13 +115,8 @@ class MediaTransportHandler {
 
   virtual void UpdateNetworkState(bool aOnline) = 0;
 
-  // dom::RTCStatsReportInternal doesn't have move semantics.
-  typedef MozPromise<std::unique_ptr<dom::RTCStatsReportInternal>, nsresult,
-                     true>
-      StatsPromise;
-  virtual RefPtr<StatsPromise> GetIceStats(
-      const std::string& aTransportId, DOMHighResTimeStamp aNow,
-      std::unique_ptr<dom::RTCStatsReportInternal>&& aReport) = 0;
+  virtual RefPtr<dom::RTCStatsPromise> GetIceStats(
+      const std::string& aTransportId, DOMHighResTimeStamp aNow) = 0;
 
   sigslot::signal2<const std::string&, const CandidateInfo&> SignalCandidate;
   sigslot::signal2<const std::string&, bool> SignalAlpnNegotiated;
diff --git a/media/webrtc/signaling/src/peerconnection/MediaTransportHandlerIPC.cpp b/media/webrtc/signaling/src/peerconnection/MediaTransportHandlerIPC.cpp
index 9d020e1a9a..12d72de922 100644
--- a/media/webrtc/signaling/src/peerconnection/MediaTransportHandlerIPC.cpp
+++ b/media/webrtc/signaling/src/peerconnection/MediaTransportHandlerIPC.cpp
@@ -297,35 +297,35 @@ void MediaTransportHandlerIPC::UpdateNetworkState(bool aOnline) {
       [](const nsCString& aError) {});
 }
 
-RefPtr<MediaTransportHandler::StatsPromise>
-MediaTransportHandlerIPC::GetIceStats(
-    const std::string& aTransportId, DOMHighResTimeStamp aNow,
-    std::unique_ptr<dom::RTCStatsReportInternal>&& aReport) {
+RefPtr<dom::RTCStatsPromise> MediaTransportHandlerIPC::GetIceStats(
+    const std::string& aTransportId, DOMHighResTimeStamp aNow) {
   return mInitPromise->Then(
       mCallbackThread, __func__,
-      [aReport = std::move(aReport), aTransportId, aNow, this,
-       self = RefPtr<MediaTransportHandlerIPC>(this)](bool /*dummy*/) mutable {
+      [aTransportId, aNow, this,
+       self = RefPtr<MediaTransportHandlerIPC>(this)](bool /*dummy*/) {
         if (!mChild) {
-          return StatsPromise::CreateAndReject(NS_ERROR_FAILURE, __func__);
+          return dom::RTCStatsPromise::CreateAndReject(NS_ERROR_FAILURE,
+                                                       __func__);
         }
-        RefPtr<StatsPromise> promise =
-            mChild->SendGetIceStats(aTransportId, aNow, *aReport)
+        RefPtr<dom::RTCStatsPromise> promise =
+            mChild->SendGetIceStats(aTransportId, aNow)
                 ->Then(
                     mCallbackThread, __func__,
-                    [](const dom::MovableRTCStatsReportInternal& aReport) {
-                      std::unique_ptr<dom::RTCStatsReportInternal> report(
-                          new dom::RTCStatsReportInternal(aReport));
-                      return StatsPromise::CreateAndResolve(std::move(report),
-                                                            __func__);
+                    [](const dom::RTCStatsCollection& aStats) {
+                      UniquePtr<dom::RTCStatsCollection> stats(
+                          new dom::RTCStatsCollection(aStats));
+                      return dom::RTCStatsPromise::CreateAndResolve(
+                          std::move(stats), __func__);
                     },
                     [](ipc::ResponseRejectReason aReason) {
-                      return StatsPromise::CreateAndReject(NS_ERROR_FAILURE,
-                                                           __func__);
+                      return dom::RTCStatsPromise::CreateAndReject(
+                          NS_ERROR_FAILURE, __func__);
                     });
         return promise;
       },
       [](const nsCString& aError) {
-        return StatsPromise::CreateAndReject(NS_ERROR_FAILURE, __func__);
+        return dom::RTCStatsPromise::CreateAndReject(NS_ERROR_FAILURE,
+                                                     __func__);
       });
 }
 
diff --git a/media/webrtc/signaling/src/peerconnection/MediaTransportHandlerIPC.h b/media/webrtc/signaling/src/peerconnection/MediaTransportHandlerIPC.h
index f01b02f542..cc75eabf47 100644
--- a/media/webrtc/signaling/src/peerconnection/MediaTransportHandlerIPC.h
+++ b/media/webrtc/signaling/src/peerconnection/MediaTransportHandlerIPC.h
@@ -71,9 +71,8 @@ class MediaTransportHandlerIPC : public MediaTransportHandler {
 
   void UpdateNetworkState(bool aOnline) override;
 
-  RefPtr<StatsPromise> GetIceStats(
-      const std::string& aTransportId, DOMHighResTimeStamp aNow,
-      std::unique_ptr<dom::RTCStatsReportInternal>&& aReport) override;
+  RefPtr<dom::RTCStatsPromise> GetIceStats(const std::string& aTransportId,
+                                           DOMHighResTimeStamp aNow) override;
 
  private:
   friend class MediaTransportChild;
diff --git a/media/webrtc/signaling/src/peerconnection/MediaTransportParent.cpp b/media/webrtc/signaling/src/peerconnection/MediaTransportParent.cpp
index 9f70099642..6e222f3e5c 100644
--- a/media/webrtc/signaling/src/peerconnection/MediaTransportParent.cpp
+++ b/media/webrtc/signaling/src/peerconnection/MediaTransportParent.cpp
@@ -214,26 +214,21 @@ mozilla::ipc::IPCResult MediaTransportParent::RecvUpdateNetworkState(
 
 mozilla::ipc::IPCResult MediaTransportParent::RecvGetIceStats(
     const string& transportId, const double& now,
-    const RTCStatsReportInternal& reportIn, GetIceStatsResolver&& aResolve) {
-  // Copy, because we are handed a const reference (lame), and put in a
-  // unique_ptr because RTCStatsReportInternal doesn't have move semantics
-  // (also lame).
-  std::unique_ptr<dom::RTCStatsReportInternal> report(
-      new dom::RTCStatsReportInternal(reportIn));
-
-  mImpl->mHandler->GetIceStats(transportId, now, std::move(report))
+    GetIceStatsResolver&& aResolve) {
+  mImpl->mHandler->GetIceStats(transportId, now)
       ->Then(
           GetCurrentThreadSerialEventTarget(), __func__,
           // IPDL doesn't give us a reject function, so we cannot reject async,
           // so we are forced to resolve with an unmodified result. Laaaaaaame.
-          [aResolve = std::move(aResolve),
-           reportIn](MediaTransportHandler::StatsPromise::ResolveOrRejectValue&&
-                         aResult) {
+          [aResolve = std::move(aResolve)](
+              dom::RTCStatsPromise::ResolveOrRejectValue&& aResult) {
             if (aResult.IsResolve()) {
-              MovableRTCStatsReportInternal copy(*aResult.ResolveValue());
-              aResolve(copy);
+              aResolve(
+                  dom::NotReallyMovableButLetsPretendItIsRTCStatsCollection(
+                      *aResult.ResolveValue()));
             } else {
-              aResolve(MovableRTCStatsReportInternal(reportIn));
+              dom::NotReallyMovableButLetsPretendItIsRTCStatsCollection empty;
+              aResolve(empty);
             }
           });
 
diff --git a/media/webrtc/signaling/src/peerconnection/PeerConnectionCtx.cpp b/media/webrtc/signaling/src/peerconnection/PeerConnectionCtx.cpp
index 389d952c5a..dd8efc140a 100644
--- a/media/webrtc/signaling/src/peerconnection/PeerConnectionCtx.cpp
+++ b/media/webrtc/signaling/src/peerconnection/PeerConnectionCtx.cpp
@@ -177,10 +177,7 @@ template <typename T>
 static void RecordCommonRtpTelemetry(const T& list, const T& lastList,
                                      const bool isRemote) {
   using namespace Telemetry;
-  if (!list.WasPassed()) {
-    return;
-  }
-  for (const auto& s : list.Value()) {
+  for (const auto& s : list) {
     const bool isAudio = s.mKind.Value().Find("audio") != -1;
     if (s.mPacketsLost.WasPassed() && s.mPacketsReceived.WasPassed()) {
       if (const uint64_t total =
@@ -202,8 +199,8 @@ static void RecordCommonRtpTelemetry(const T& list, const T& lastList,
       Accumulate(id, s.mJitter.Value() * 1000);
     }
     // Record bandwidth telemetry
-    if (s.mBytesReceived.WasPassed() && lastList.WasPassed()) {
-      for (const auto& lastS : lastList.Value()) {
+    if (s.mBytesReceived.WasPassed()) {
+      for (const auto& lastS : lastList) {
         if (lastS.mId == s.mId) {
           int32_t deltaMs = s.mTimestamp.Value() - lastS.mTimestamp.Value();
           // In theory we're called every second, so delta *should* be in that
@@ -238,37 +235,35 @@ static void RecordCommonRtpTelemetry(const T& list, const T& lastList,
 //   STS,
 // - hence the there and back again approach.
 
-void PeerConnectionCtx::DeliverStats(RTCStatsQuery& aQuery) {
+void PeerConnectionCtx::DeliverStats(
+    UniquePtr<dom::RTCStatsReportInternal>&& aReport) {
   using namespace Telemetry;
 
-  std::unique_ptr<dom::RTCStatsReportInternal> report(std::move(aQuery.report));
   // First, get reports from a second ago, if any, for calculations below
-  std::unique_ptr<dom::RTCStatsReportInternal> lastReport;
+  UniquePtr<dom::RTCStatsReportInternal> lastReport;
   {
-    auto i = mLastReports.find(report->mPcid);
+    auto i = mLastReports.find(aReport->mPcid);
     if (i != mLastReports.end()) {
       lastReport = std::move(i->second);
     } else {
-      lastReport = std::make_unique<dom::RTCStatsReportInternal>();
+      lastReport = MakeUnique<dom::RTCStatsReportInternal>();
     }
   }
   // Record Telemetery
-  RecordCommonRtpTelemetry(report->mInboundRtpStreamStats,
+  RecordCommonRtpTelemetry(aReport->mInboundRtpStreamStats,
                            lastReport->mInboundRtpStreamStats, false);
-  RecordCommonRtpTelemetry(report->mRemoteInboundRtpStreamStats,
+  RecordCommonRtpTelemetry(aReport->mRemoteInboundRtpStreamStats,
                            lastReport->mRemoteInboundRtpStreamStats, true);
-  if (report->mRemoteInboundRtpStreamStats.WasPassed()) {
-    for (const auto& s : report->mRemoteInboundRtpStreamStats.Value()) {
-      if (s.mRoundTripTime.WasPassed()) {
-        const bool isAudio = s.mKind.Value().Find("audio") != -1;
-        HistogramID id = isAudio ? WEBRTC_AUDIO_QUALITY_OUTBOUND_RTT
-                                 : WEBRTC_VIDEO_QUALITY_OUTBOUND_RTT;
-        Accumulate(id, s.mRoundTripTime.Value() * 1000);
-      }
+  for (const auto& s : aReport->mRemoteInboundRtpStreamStats) {
+    if (s.mRoundTripTime.WasPassed()) {
+      const bool isAudio = s.mKind.Value().Find("audio") != -1;
+      HistogramID id = isAudio ? WEBRTC_AUDIO_QUALITY_OUTBOUND_RTT
+                               : WEBRTC_VIDEO_QUALITY_OUTBOUND_RTT;
+      Accumulate(id, s.mRoundTripTime.Value() * 1000);
     }
   }
 
-  mLastReports[report->mPcid] = std::move(report);
+  mLastReports[aReport->mPcid] = std::move(aReport);
 }
 
 void PeerConnectionCtx::EverySecondTelemetryCallback_m(nsITimer* timer,
@@ -278,12 +273,13 @@ void PeerConnectionCtx::EverySecondTelemetryCallback_m(nsITimer* timer,
 
   for (auto& idAndPc : GetInstance()->mPeerConnections) {
     if (idAndPc.second->HasMedia()) {
-      idAndPc.second->GetStats(nullptr, true, true)
+      idAndPc.second->GetStats(nullptr, true)
           ->Then(
               GetMainThreadSerialEventTarget(), __func__,
-              [=](UniquePtr<RTCStatsQuery>&& aQuery) {
+              [=](UniquePtr<dom::RTCStatsReportInternal>&& aReport) {
                 if (PeerConnectionCtx::isActive()) {
-                  PeerConnectionCtx::GetInstance()->DeliverStats(*aQuery);
+                  PeerConnectionCtx::GetInstance()->DeliverStats(
+                      std::move(aReport));
                 }
               },
               [=](nsresult aError) {});
diff --git a/media/webrtc/signaling/src/peerconnection/PeerConnectionCtx.h b/media/webrtc/signaling/src/peerconnection/PeerConnectionCtx.h
index b9e987c304..8d9aada000 100644
--- a/media/webrtc/signaling/src/peerconnection/PeerConnectionCtx.h
+++ b/media/webrtc/signaling/src/peerconnection/PeerConnectionCtx.h
@@ -90,10 +90,9 @@ class PeerConnectionCtx {
   nsCOMPtr<nsITimer> mTelemetryTimer;
 
  private:
-  void DeliverStats(RTCStatsQuery& aQuery);
+  void DeliverStats(UniquePtr<dom::RTCStatsReportInternal>&& aReport);
 
-  std::map<nsString, std::unique_ptr<mozilla::dom::RTCStatsReportInternal>>
-      mLastReports;
+  std::map<nsString, UniquePtr<dom::RTCStatsReportInternal>> mLastReports;
   // We cannot form offers/answers properly until the Gecko Media Plugin stuff
   // has been initted, which is a complicated mess of thread dispatches,
   // including sync dispatches to main. So, we need to be able to queue up
diff --git a/media/webrtc/signaling/src/peerconnection/PeerConnectionImpl.cpp b/media/webrtc/signaling/src/peerconnection/PeerConnectionImpl.cpp
index 1b0d4eb8c3..fddb44d6c5 100644
--- a/media/webrtc/signaling/src/peerconnection/PeerConnectionImpl.cpp
+++ b/media/webrtc/signaling/src/peerconnection/PeerConnectionImpl.cpp
@@ -60,7 +60,6 @@
 #include "nsGlobalWindow.h"
 #include "nsDOMDataChannel.h"
 #include "mozilla/dom/Location.h"
-#include "mozilla/dom/Performance.h"
 #include "mozilla/NullPrincipal.h"
 #include "mozilla/TimeStamp.h"
 #include "mozilla/Telemetry.h"
@@ -85,7 +84,6 @@
 #include "mozilla/dom/RTCPeerConnectionBinding.h"
 #include "mozilla/dom/PeerConnectionImplBinding.h"
 #include "mozilla/dom/RTCDataChannelBinding.h"
-#include "mozilla/dom/PerformanceTiming.h"
 #include "mozilla/dom/PluginCrashedEvent.h"
 #include "MediaStreamTrack.h"
 #include "AudioStreamTrack.h"
@@ -213,14 +211,6 @@ class DataChannel;
 
 namespace mozilla {
 
-RTCStatsQuery::RTCStatsQuery(bool aInternal, bool aRecordTelemetry)
-    : internalStats(aInternal),
-      recordTelemetry(aRecordTelemetry),
-      grabAllLevels(false),
-      now(0.0) {}
-
-RTCStatsQuery::~RTCStatsQuery() {}
-
 NS_IMPL_ISUPPORTS0(PeerConnectionImpl)
 
 already_AddRefed<PeerConnectionImpl> PeerConnectionImpl::Constructor(
@@ -307,6 +297,8 @@ PeerConnectionImpl::PeerConnectionImpl(const GlobalObject* aGlobal)
       mActiveOnWindow(false),
       mPacketDumpEnabled(false),
       mPacketDumpFlagsMutex("Packet dump flags mutex"),
+      mTimestampMaker(aGlobal),
+      mIdGenerator(new RTCStatsIdGenerator()),
       listenPort(0),
       connectPort(0),
       connectStr(nullptr) {
@@ -335,8 +327,9 @@ PeerConnectionImpl::~PeerConnectionImpl() {
     destroy_timecard(mTimeCard);
     mTimeCard = nullptr;
   }
-  // This aborts if not on main thread (in Debug builds)
-  PC_AUTO_ENTER_API_CALL_NO_CHECK();
+
+  MOZ_ASSERT(NS_IsMainThread());
+
   if (mWindow && mActiveOnWindow) {
     mWindow->RemovePeerConnection();
     // No code is supposed to observe the assignment below, but
@@ -1450,52 +1443,35 @@ PeerConnectionImpl::SetRemoteDescription(int32_t action, const char* aSDP) {
   return NS_OK;
 }
 
-// WebRTC uses highres time relative to the UNIX epoch (Jan 1, 1970, UTC).
-
-nsresult PeerConnectionImpl::GetTimeSinceEpoch(DOMHighResTimeStamp* result) {
-  MOZ_ASSERT(NS_IsMainThread());
-  Performance* perf = mWindow->GetPerformance();
-  NS_ENSURE_TRUE(perf && perf->Timing(), NS_ERROR_UNEXPECTED);
-  *result = perf->Now() + perf->Timing()->NavigationStart();
-  return NS_OK;
-}
-
-class RTCStatsReportInternalConstruct : public RTCStatsReportInternal {
- public:
-  RTCStatsReportInternalConstruct(const nsString& pcid,
-                                  DOMHighResTimeStamp now) {
-    mPcid = pcid;
-    mRtpContributingSourceStats.Construct();
-    mInboundRtpStreamStats.Construct();
-    mOutboundRtpStreamStats.Construct();
-    mRemoteInboundRtpStreamStats.Construct();
-    mRemoteOutboundRtpStreamStats.Construct();
-    mIceCandidatePairStats.Construct();
-    mIceCandidateStats.Construct();
-    mTimestamp.Construct(now);
-    mTrickledIceCandidateStats.Construct();
-    mRawLocalCandidates.Construct();
-    mRawRemoteCandidates.Construct();
+already_AddRefed<dom::Promise> PeerConnectionImpl::GetStats(
+    MediaStreamTrack* aSelector) {
+  if (NS_FAILED(CheckApiState(false))) {
+    return nullptr;
   }
-};
 
-NS_IMETHODIMP
-PeerConnectionImpl::GetStats(MediaStreamTrack* aSelector) {
-  PC_AUTO_ENTER_API_CALL(true);
+  nsCOMPtr<nsIGlobalObject> global = do_QueryInterface(mWindow);
+  ErrorResult rv;
+  RefPtr<Promise> promise = Promise::Create(global, rv);
+  if (NS_WARN_IF(rv.Failed())) {
+    rv.StealNSResult();
+    return nullptr;
+  }
 
-  GetStats(aSelector, false, false)
+  GetStats(aSelector, false)
       ->Then(
           GetMainThreadSerialEventTarget(), __func__,
-          [handle = mHandle](UniquePtr<RTCStatsQuery>&& aQuery) {
-            DeliverStatsReportToPCObserver_m(
-                handle, NS_OK, nsAutoPtr<RTCStatsQuery>(aQuery.release()));
+          [promise,
+           window = mWindow](UniquePtr<dom::RTCStatsReportInternal>&& aReport) {
+            RefPtr<RTCStatsReport> report(new RTCStatsReport(window));
+            report->Incorporate(*aReport);
+            promise->MaybeResolve(std::move(report));
           },
-          [handle = mHandle](nsresult aError) {
-            DeliverStatsReportToPCObserver_m(handle, aError,
-                                             nsAutoPtr<RTCStatsQuery>());
+          [promise, window = mWindow](nsresult aError) {
+            RefPtr<RTCStatsReport> report(new RTCStatsReport(window));
+            promise->MaybeResolve(std::move(report));
           });
 
-  return NS_OK;
+  return promise.forget();
 }
 
 NS_IMETHODIMP
@@ -1691,15 +1667,16 @@ DOMHighResTimeStamp PeerConnectionImpl::GetNowInRtpSourceReferenceTime() {
 
 // test-only: adds fake CSRCs and audio data
 nsresult PeerConnectionImpl::InsertAudioLevelForContributingSource(
-    dom::MediaStreamTrack& aRecvTrack, unsigned long aSource,
-    DOMHighResTimeStamp aTimestamp, bool aHasLevel, uint8_t aLevel) {
+    const dom::MediaStreamTrack& aRecvTrack, const unsigned long aSource,
+    const DOMHighResTimeStamp aTimestamp, const unsigned long aRtpTimestamp,
+    const bool aHasLevel, const uint8_t aLevel) {
   PC_AUTO_ENTER_API_CALL(true);
   std::vector<RefPtr<TransceiverImpl>>& transceivers =
       mMedia->GetTransceivers();
   for (RefPtr<TransceiverImpl>& transceiver : transceivers) {
     if (transceiver->HasReceiveTrack(&aRecvTrack)) {
-      transceiver->InsertAudioLevelForContributingSource(aSource, aTimestamp,
-                                                         aHasLevel, aLevel);
+      transceiver->InsertAudioLevelForContributingSource(
+          aSource, aTimestamp, aRtpTimestamp, aHasLevel, aLevel);
       break;
     }
   }
@@ -1904,13 +1881,21 @@ PeerConnectionImpl::ReplaceTrackNoRenegotiation(TransceiverImpl& aTransceiver,
     PrincipalChanged(aWithTrack);
   }
 
-  // We update the media pipelines here so we can apply different codec
-  // settings for different sources (e.g. screensharing as opposed to camera.)
-  // TODO: We should probably only do this if the source has in fact changed.
-
-  if (NS_FAILED((rv = mMedia->UpdateMediaPipelines()))) {
-    CSFLogError(LOGTAG, "Error Updating MediaPipelines");
-    return rv;
+  if (aTransceiver.IsVideo()) {
+    // We update the media pipelines here so we can apply different codec
+    // settings for different sources (e.g. screensharing as opposed to camera.)
+    MediaSourceEnum oldSource = oldSendTrack
+                                    ? oldSendTrack->GetSource().GetMediaSource()
+                                    : MediaSourceEnum::Camera;
+    MediaSourceEnum newSource = aWithTrack
+                                    ? aWithTrack->GetSource().GetMediaSource()
+                                    : MediaSourceEnum::Camera;
+    if (oldSource != newSource) {
+      if (NS_WARN_IF(NS_FAILED(rv = aTransceiver.UpdateConduit()))) {
+        CSFLogError(LOGTAG, "Error Updating VideoConduit");
+        return rv;
+      }
+    }
   }
 
   return NS_OK;
@@ -2160,7 +2145,7 @@ nsresult PeerConnectionImpl::CloseInt() {
 }
 
 void PeerConnectionImpl::ShutdownMedia() {
-  PC_AUTO_ENTER_API_CALL_NO_CHECK();
+  MOZ_ASSERT(NS_IsMainThread());
 
   if (!mMedia) return;
 
@@ -2191,6 +2176,17 @@ void PeerConnectionImpl::SetSignalingState_m(RTCSignalingState aSignalingState,
     return;
   }
 
+  // We'd like to handle this in PeerConnectionMedia::UpdateNetworkState.
+  // Unfortunately, if the WiFi switch happens quickly, we never see
+  // that state change.  We need to detect the ice restart here and
+  // reset the PeerConnectionMedia's stun addresses so they are
+  // regathered when PeerConnectionMedia::GatherIfReady is called.
+  if ((aSignalingState == RTCSignalingState::Have_local_offer ||
+       aSignalingState == RTCSignalingState::Have_remote_offer) &&
+      !rollback && mJsepSession->IsIceRestarting()) {
+    mMedia->ResetStunAddrsForIceRestart();
+  }
+
   if (aSignalingState == RTCSignalingState::Have_local_offer ||
       (aSignalingState == RTCSignalingState::Stable &&
        mSignalingState == RTCSignalingState::Have_remote_offer && !rollback)) {
@@ -2479,55 +2475,336 @@ void PeerConnectionImpl::UpdateDefaultCandidate(
       defaultAddr, defaultPort, defaultRtcpAddr, defaultRtcpPort, transportId);
 }
 
-RefPtr<RTCStatsQueryPromise> PeerConnectionImpl::GetStats(
-    dom::MediaStreamTrack* aSelector, bool aInternalStats,
-    bool aRecordTelemetry) {
-  UniquePtr<RTCStatsQuery> query(
-      new RTCStatsQuery(aInternalStats, aRecordTelemetry));
-  nsresult rv = BuildStatsQuery_m(aSelector, query.get());
-  if (NS_FAILED(rv)) {
-    return RTCStatsQueryPromise::CreateAndReject(rv, __func__);
+// TODO(bug 1586109): Move this to RTCRtpReceiver.
+static UniquePtr<dom::RTCStatsCollection> GetReceiverStats_s(
+    const RefPtr<MediaPipelineReceive>& aPipeline) {
+  UniquePtr<dom::RTCStatsCollection> report(new dom::RTCStatsCollection);
+  auto asVideo = aPipeline->Conduit()->AsVideoSessionConduit();
+
+  nsString kind = asVideo.isNothing() ? NS_LITERAL_STRING("audio")
+                                      : NS_LITERAL_STRING("video");
+  nsString idstr = kind + NS_LITERAL_STRING("_");
+  idstr.AppendInt(static_cast<uint32_t>(aPipeline->Level()));
+
+  // TODO(@@NG):ssrcs handle Conduits having multiple stats at the same level
+  // This is pending spec work
+  // Gather pipeline stats.
+  nsString localId = NS_LITERAL_STRING("inbound_rtp_") + idstr;
+  nsString remoteId;
+  Maybe<uint32_t> ssrc;
+  unsigned int ssrcval;
+  if (aPipeline->Conduit()->GetRemoteSSRC(&ssrcval)) {
+    ssrc = Some(ssrcval);
   }
 
-  nsTArray<RefPtr<MediaPipeline>> pipelines;
-  // Gather up pipelines from mMedia so they may be inspected on STS
-  mMedia->GetTransmitPipelinesMatching(aSelector, &pipelines);
-  mMedia->GetReceivePipelinesMatching(aSelector, &pipelines);
-  if (!pipelines.Length()) {
-    CSFLogError(LOGTAG, "%s: Found no pipelines matching selector.",
-                __FUNCTION__);
+  RTCInboundRtpStreamStats mInboundRtp;
+  nsTArray<RTCRTPContributingSourceStats> mCsrcs;
+  // First, fill in remote stat with rtcp sender data, if present.
+  uint32_t packetsSent;
+  uint64_t bytesSent;
+  Maybe<DOMHighResTimeStamp> timestamp =
+      aPipeline->Conduit()->LastRtcpReceived();
+  if (timestamp.isSome() &&
+      aPipeline->Conduit()->GetRTCPSenderReport(&packetsSent, &bytesSent)) {
+    RTCRemoteOutboundRtpStreamStats s;
+    remoteId = NS_LITERAL_STRING("inbound_rtcp_") + idstr;
+    s.mTimestamp.Construct(*timestamp);
+    s.mId.Construct(remoteId);
+    s.mType.Construct(RTCStatsType::Remote_outbound_rtp);
+    ssrc.apply([&s](uint32_t aSsrc) { s.mSsrc.Construct(aSsrc); });
+    s.mMediaType.Construct(kind);  // mediaType is the old name for kind.
+    s.mKind.Construct(kind);
+    s.mLocalId.Construct(localId);
+    s.mPacketsSent.Construct(packetsSent);
+    s.mBytesSent.Construct(bytesSent);
+    if (!report->mRemoteOutboundRtpStreamStats.AppendElement(s, fallible)) {
+      mozalloc_handle_oom(0);
+    }
   }
 
-  return InvokeAsync(mSTSThread, __func__,
-                     [transportHandler = mMedia->mTransportHandler, pipelines,
-                      aQuery = std::move(query)]() mutable {
-                       return PeerConnectionImpl::ExecuteStatsQuery_s(
-                           std::move(aQuery), pipelines, transportHandler);
-                     });
+  // Then, fill in local side (with cross-link to remote only if present)
+  RTCInboundRtpStreamStats s;
+  // TODO(bug 1496533): Should we use the time of the most-recently received RTP
+  // packet? If so, what do we use if we haven't received any RTP? Now?
+  s.mTimestamp.Construct(aPipeline->GetNow());
+  s.mId.Construct(localId);
+  s.mType.Construct(RTCStatsType::Inbound_rtp);
+  ssrc.apply([&s](uint32_t aSsrc) { s.mSsrc.Construct(aSsrc); });
+  s.mMediaType.Construct(kind);  // mediaType is the old name for kind.
+  s.mKind.Construct(kind);
+  unsigned int jitterMs, packetsLost;
+  if (aPipeline->Conduit()->GetRTPReceiverStats(&jitterMs, &packetsLost)) {
+    s.mJitter.Construct(double(jitterMs) / 1000);
+    s.mPacketsLost.Construct(packetsLost);
+  }
+  if (remoteId.Length()) {
+    s.mRemoteId.Construct(remoteId);
+  }
+  s.mPacketsReceived.Construct(aPipeline->RtpPacketsReceived());
+  s.mBytesReceived.Construct(aPipeline->RtpBytesReceived());
+
+  // Fill in packet type statistics
+  webrtc::RtcpPacketTypeCounter counters;
+  if (aPipeline->Conduit()->GetRecvPacketTypeStats(&counters)) {
+    s.mNackCount.Construct(counters.nack_packets);
+    // Fill in video only packet type stats
+    if (asVideo) {
+      s.mFirCount.Construct(counters.fir_packets);
+      s.mPliCount.Construct(counters.pli_packets);
+    }
+  }
+  // Lastly, fill in video decoder stats if this is video
+  asVideo.apply([&s](auto conduit) {
+    double framerateMean;
+    double framerateStdDev;
+    double bitrateMean;
+    double bitrateStdDev;
+    uint32_t discardedPackets;
+    uint32_t framesDecoded;
+    if (conduit->GetVideoDecoderStats(&framerateMean, &framerateStdDev,
+                                      &bitrateMean, &bitrateStdDev,
+                                      &discardedPackets, &framesDecoded)) {
+      s.mFramerateMean.Construct(framerateMean);
+      s.mFramerateStdDev.Construct(framerateStdDev);
+      s.mBitrateMean.Construct(bitrateMean);
+      s.mBitrateStdDev.Construct(bitrateStdDev);
+      s.mDiscardedPackets.Construct(discardedPackets);
+      s.mFramesDecoded.Construct(framesDecoded);
+    }
+  });
+  if (!report->mInboundRtpStreamStats.AppendElement(s, fallible)) {
+    mozalloc_handle_oom(0);
+  }
+
+  // Fill in Contributing Source statistics
+  aPipeline->GetContributingSourceStats(localId,
+                                        report->mRtpContributingSourceStats);
+  return report;
 }
 
-nsresult PeerConnectionImpl::BuildStatsQuery_m(
-    mozilla::dom::MediaStreamTrack* aSelector, RTCStatsQuery* query) {
-  if (!HasMedia()) {
-    return NS_ERROR_UNEXPECTED;
+// TODO(bug 1586109): Move this to RTCRtpSender.
+static UniquePtr<dom::RTCStatsCollection> GetSenderStats_s(
+    const RefPtr<MediaPipelineTransmit>& aPipeline) {
+  UniquePtr<dom::RTCStatsCollection> report(new dom::RTCStatsCollection);
+  auto asVideo = aPipeline->Conduit()->AsVideoSessionConduit();
+
+  nsString kind = asVideo.isNothing() ? NS_LITERAL_STRING("audio")
+                                      : NS_LITERAL_STRING("video");
+  nsString idstr = kind + NS_LITERAL_STRING("_");
+  idstr.AppendInt(static_cast<uint32_t>(aPipeline->Level()));
+
+  // TODO(@@NG):ssrcs handle Conduits having multiple stats at the same level
+  // This is pending spec work
+  // Gather pipeline stats.
+  nsString localId = NS_LITERAL_STRING("outbound_rtp_") + idstr;
+  nsString remoteId;
+  Maybe<uint32_t> ssrc;
+  std::vector<unsigned int> ssrcvals = aPipeline->Conduit()->GetLocalSSRCs();
+  if (!ssrcvals.empty()) {
+    ssrc = Some(ssrcvals[0]);
+  }
+  {
+    // First, fill in remote stat with rtcp receiver data, if present.
+    // ReceiverReports have less information than SenderReports,
+    // so fill in what we can.
+    uint32_t jitterMs;
+    uint32_t packetsReceived;
+    uint64_t bytesReceived;
+    uint32_t packetsLost;
+    Maybe<double> rtt;
+    Maybe<DOMHighResTimeStamp> timestamp =
+        aPipeline->Conduit()->LastRtcpReceived();
+    if (timestamp.isSome() &&
+        aPipeline->Conduit()->GetRTCPReceiverReport(
+            &jitterMs, &packetsReceived, &bytesReceived, &packetsLost, &rtt)) {
+      remoteId = NS_LITERAL_STRING("outbound_rtcp_") + idstr;
+      RTCRemoteInboundRtpStreamStats s;
+      s.mTimestamp.Construct(*timestamp);
+      s.mId.Construct(remoteId);
+      s.mType.Construct(RTCStatsType::Remote_inbound_rtp);
+      ssrc.apply([&s](uint32_t aSsrc) { s.mSsrc.Construct(aSsrc); });
+      s.mMediaType.Construct(kind);  // mediaType is the old name for kind.
+      s.mKind.Construct(kind);
+      s.mJitter.Construct(double(jitterMs) / 1000);
+      s.mLocalId.Construct(localId);
+      s.mPacketsReceived.Construct(packetsReceived);
+      s.mBytesReceived.Construct(bytesReceived);
+      s.mPacketsLost.Construct(packetsLost);
+      rtt.apply([&s](auto r) { s.mRoundTripTime.Construct(r); });
+      if (!report->mRemoteInboundRtpStreamStats.AppendElement(s, fallible)) {
+        mozalloc_handle_oom(0);
+      }
+    }
+  }
+  // Then, fill in local side (with cross-link to remote only if present)
+  RTCOutboundRtpStreamStats s;
+  s.mTimestamp.Construct(aPipeline->GetNow());
+  s.mId.Construct(localId);
+  s.mType.Construct(RTCStatsType::Outbound_rtp);
+  ssrc.apply([&s](uint32_t aSsrc) { s.mSsrc.Construct(aSsrc); });
+  s.mMediaType.Construct(kind);  // mediaType is the old name for kind.
+  s.mKind.Construct(kind);
+  if (remoteId.Length()) {
+    s.mRemoteId.Construct(remoteId);
+  }
+  s.mPacketsSent.Construct(aPipeline->RtpPacketsSent());
+  s.mBytesSent.Construct(aPipeline->RtpBytesSent());
+
+  // Fill in packet type statistics
+  webrtc::RtcpPacketTypeCounter counters;
+  if (aPipeline->Conduit()->GetSendPacketTypeStats(&counters)) {
+    s.mNackCount.Construct(counters.nack_packets);
+    // Fill in video only packet type stats
+    if (asVideo) {
+      s.mFirCount.Construct(counters.fir_packets);
+      s.mPliCount.Construct(counters.pli_packets);
+    }
   }
 
-  nsresult rv = GetTimeSinceEpoch(&(query->now));
-  if (NS_FAILED(rv)) {
-    CSFLogError(LOGTAG, "Could not build stats query, could not get timestamp");
-    return rv;
+  // Lastly, fill in video encoder stats if this is video
+  asVideo.apply([&s](auto conduit) {
+    double framerateMean;
+    double framerateStdDev;
+    double bitrateMean;
+    double bitrateStdDev;
+    uint32_t droppedFrames;
+    uint32_t framesEncoded;
+    Maybe<uint64_t> qpSum;
+    if (conduit->GetVideoEncoderStats(&framerateMean, &framerateStdDev,
+                                      &bitrateMean, &bitrateStdDev,
+                                      &droppedFrames, &framesEncoded, &qpSum)) {
+      s.mFramerateMean.Construct(framerateMean);
+      s.mFramerateStdDev.Construct(framerateStdDev);
+      s.mBitrateMean.Construct(bitrateMean);
+      s.mBitrateStdDev.Construct(bitrateStdDev);
+      s.mDroppedFrames.Construct(droppedFrames);
+      s.mFramesEncoded.Construct(framesEncoded);
+      qpSum.apply([&s](uint64_t aQp) { s.mQpSum.Construct(aQp); });
+    }
+  });
+  if (!report->mOutboundRtpStreamStats.AppendElement(s, fallible)) {
+    mozalloc_handle_oom(0);
+  }
+  return report;
+}
+
+RefPtr<dom::RTCStatsPromise> PeerConnectionImpl::GetReceiverStats(
+    const RefPtr<MediaPipelineReceive>& aPipeline) {
+  return InvokeAsync(mSTSThread, __func__, [aPipeline]() {
+    return dom::RTCStatsPromise::CreateAndResolve(GetReceiverStats_s(aPipeline),
+                                                  __func__);
+  });
+}
+
+RefPtr<dom::RTCStatsPromise> PeerConnectionImpl::GetSenderStats(
+    const RefPtr<MediaPipelineTransmit>& aPipeline) {
+  return InvokeAsync(mSTSThread, __func__, [aPipeline]() {
+    return dom::RTCStatsPromise::CreateAndResolve(GetSenderStats_s(aPipeline),
+                                                  __func__);
+  });
+}
+
+template <class T>
+void AssignWithOpaqueIds(dom::Sequence<T>& aSource, dom::Sequence<T>& aDest,
+                         RefPtr<RTCStatsIdGenerator>& aGenerator) {
+  for (auto& stat : aSource) {
+    stat.mId.Value() = aGenerator->Id(stat.mId.Value());
+  }
+  if (!aDest.AppendElements(aSource, fallible)) {
+    mozalloc_handle_oom(0);
+  }
+}
+
+template <class T>
+void RewriteRemoteIds(dom::Sequence<T>& aList,
+                      RefPtr<RTCStatsIdGenerator>& aGenerator) {
+  for (auto& stat : aList) {
+    if (stat.mRemoteId.WasPassed()) {
+      stat.mRemoteId.Value() = aGenerator->Id(stat.mRemoteId.Value());
+    }
+  }
+}
+
+template <class T>
+void RewriteLocalIds(dom::Sequence<T>& aList,
+                     RefPtr<RTCStatsIdGenerator>& aGenerator) {
+  for (auto& stat : aList) {
+    if (stat.mLocalId.WasPassed()) {
+      stat.mLocalId.Value() = aGenerator->Id(stat.mLocalId.Value());
+    }
+  }
+}
+
+RefPtr<dom::RTCStatsReportPromise> PeerConnectionImpl::GetStats(
+    dom::MediaStreamTrack* aSelector, bool aInternalStats) {
+  nsTArray<RefPtr<dom::RTCStatsPromise>> promises;
+  DOMHighResTimeStamp now = mTimestampMaker.GetNow();
+
+  if (mMedia) {
+    nsTArray<RefPtr<MediaPipelineTransmit>> sendPipelines;
+    // Gather up pipelines from mMedia so they may be inspected on STS
+    // TODO(bug 1586109): Use RTCRtpSender for these instead.
+    mMedia->GetTransmitPipelinesMatching(aSelector, &sendPipelines);
+    if (!sendPipelines.Length()) {
+      CSFLogError(LOGTAG, "%s: Found no pipelines matching selector.",
+                  __FUNCTION__);
+    }
+
+    for (const auto& pipeline : sendPipelines) {
+      promises.AppendElement(GetSenderStats(pipeline));
+    }
+
+    nsTArray<RefPtr<MediaPipelineReceive>> recvPipelines;
+    // Gather up pipelines from mMedia so they may be inspected on STS
+    // TODO(bug 1586109): Use RTCRtpReceiver for these instead.
+    mMedia->GetReceivePipelinesMatching(aSelector, &recvPipelines);
+    if (!recvPipelines.Length()) {
+      CSFLogError(LOGTAG, "%s: Found no pipelines matching selector.",
+                  __FUNCTION__);
+    }
+
+    for (const auto& pipeline : recvPipelines) {
+      promises.AppendElement(GetReceiverStats(pipeline));
+    }
+
+    // TODO(bug 1586109): We need to move this is RTCRtpSender/Receiver, to make
+    // getStats on those objects work properly. It might be worth optimizing the
+    // null selector case, so we don't end up with bunches of copies of the same
+    // transport information in the final report.
+    std::string transportId;
+    if (aSelector) {
+      transportId = mMedia->GetTransportIdMatching(*aSelector);
+    }
+
+    promises.AppendElement(mTransportHandler->GetIceStats(transportId, now));
   }
 
-  // We do not use the pcHandle here, since that's risky to expose to content.
-  query->report.reset(new RTCStatsReportInternalConstruct(
-      NS_ConvertASCIItoUTF16(mName.c_str()), query->now));
+  // This is what we're going to return; all the stuff in |promises| will be
+  // accumulated here.
+  UniquePtr<dom::RTCStatsReportInternal> report(
+      new dom::RTCStatsReportInternal);
+  report->mPcid = NS_ConvertASCIItoUTF16(mName.c_str());
+  // TODO(bug 1589416): We need to do better here.
+  if (!mIceStartTime.IsNull()) {
+    report->mCallDurationMs.Construct(
+        (TimeStamp::Now() - mIceStartTime).ToMilliseconds());
+  }
+  report->mIceRestarts = mIceRestartCount;
+  report->mIceRollbacks = mIceRollbackCount;
+  report->mClosed = false;
+  report->mTimestamp = now;
 
-  query->iceStartTime = mIceStartTime;
-  query->report->mIceRestarts.Construct(mIceRestartCount);
-  query->report->mIceRollbacks.Construct(mIceRollbackCount);
+  if (aInternalStats && mJsepSession) {
+    for (const auto& candidate : mRawTrickledCandidates) {
+      if (!report->mRawRemoteCandidates.AppendElement(
+              NS_ConvertASCIItoUTF16(candidate.c_str()), fallible)) {
+        // XXX(Bug 1632090) Instead of extending the array 1-by-1 (which might
+        // involve multiple reallocations) and potentially crashing here,
+        // SetCapacity could be called outside the loop once.
+        mozalloc_handle_oom(0);
+      }
+    }
 
-  // Populate SDP on main
-  if (query->internalStats) {
     if (mJsepSession) {
       // TODO we probably should report Current and Pending SDPs here
       // separately. Plus the raw SDP we got from JS (mLocalRequestedSDP).
@@ -2536,288 +2813,78 @@ nsresult PeerConnectionImpl::BuildStatsQuery_m(
           mJsepSession->GetLocalDescription(kJsepDescriptionPendingOrCurrent);
       std::string remoteDescription =
           mJsepSession->GetRemoteDescription(kJsepDescriptionPendingOrCurrent);
-      query->report->mLocalSdp.Construct(
+      report->mLocalSdp.Construct(
           NS_ConvertASCIItoUTF16(localDescription.c_str()));
-      query->report->mRemoteSdp.Construct(
+      report->mRemoteSdp.Construct(
           NS_ConvertASCIItoUTF16(remoteDescription.c_str()));
-      query->report->mOfferer.Construct(mJsepSession->IsOfferer());
-      for (const auto& candidate : mRawTrickledCandidates) {
-        if (!query->report->mRawRemoteCandidates.Value().AppendElement(
-                NS_ConvertASCIItoUTF16(candidate.c_str()), fallible)) {
-          mozalloc_handle_oom(0);
-        }
-      }
+      report->mOfferer.Construct(mJsepSession->IsOfferer());
     }
   }
 
-  if (aSelector) {
-    query->transportId = mMedia->GetTransportIdMatching(*aSelector);
-  }
-
-  if (!aSelector) {
-    query->grabAllLevels = true;
-  }
-
-  return NS_OK;
-}
-
-RefPtr<RTCStatsQueryPromise> PeerConnectionImpl::ExecuteStatsQuery_s(
-    UniquePtr<RTCStatsQuery>&& query,
-    const nsTArray<RefPtr<MediaPipeline>>& aPipelines,
-    const RefPtr<MediaTransportHandler>& aTransportHandler) {
-  // Gather stats from pipelines provided (can't touch mMedia + stream on STS)
-
-  for (size_t p = 0; p < aPipelines.Length(); ++p) {
-    MOZ_ASSERT(aPipelines[p]);
-    MOZ_ASSERT(aPipelines[p]->Conduit());
-    if (!aPipelines[p] || !aPipelines[p]->Conduit()) {
-      // continue if we don't have a valid conduit
-      continue;
-    }
-    const MediaPipeline& mp = *aPipelines[p];
-    auto asVideo = mp.Conduit()->AsVideoSessionConduit();
-
-    if (query->recordTelemetry && asVideo) {
-      asVideo.value()->RecordTelemetry();
-    }
-
-    nsString kind = asVideo.isNothing() ? NS_LITERAL_STRING("audio")
-                                        : NS_LITERAL_STRING("video");
-    nsString idstr = kind + NS_LITERAL_STRING("_");
-    idstr.AppendInt(static_cast<uint32_t>(p));
-
-    // TODO(@@NG):ssrcs handle Conduits having multiple stats at the same level
-    // This is pending spec work
-    // Gather pipeline stats.
-    switch (mp.Direction()) {
-      case MediaPipeline::DirectionType::TRANSMIT: {
-        nsString localId = NS_LITERAL_STRING("outbound_rtp_") + idstr;
-        nsString remoteId;
-        Maybe<uint32_t> ssrc;
-        std::vector<unsigned int> ssrcvals = mp.Conduit()->GetLocalSSRCs();
-        if (!ssrcvals.empty()) {
-          ssrc = Some(ssrcvals[0]);
-        }
-        {
-          // First, fill in remote stat with rtcp receiver data, if present.
-          // ReceiverReports have less information than SenderReports,
-          // so fill in what we can.
-          uint32_t jitterMs;
-          uint32_t packetsReceived;
-          uint64_t bytesReceived;
-          uint32_t packetsLost;
-          Maybe<double> rtt;
-          if (mp.Conduit()->GetRTCPReceiverReport(&jitterMs, &packetsReceived,
-                                                  &bytesReceived, &packetsLost,
-                                                  &rtt)) {
-            remoteId = NS_LITERAL_STRING("outbound_rtcp_") + idstr;
-            RTCRemoteInboundRtpStreamStats s;
-            // TODO Bug 1496533 - use reception time not query time
-            s.mTimestamp.Construct(query->now);
-            s.mId.Construct(remoteId);
-            s.mType.Construct(RTCStatsType::Remote_inbound_rtp);
-            ssrc.apply([&s](uint32_t aSsrc) { s.mSsrc.Construct(aSsrc); });
-            s.mMediaType.Construct(
-                kind);  // mediaType is the old name for kind.
-            s.mKind.Construct(kind);
-            s.mJitter.Construct(double(jitterMs) / 1000);
-            s.mLocalId.Construct(localId);
-            s.mPacketsReceived.Construct(packetsReceived);
-            s.mBytesReceived.Construct(bytesReceived);
-            s.mPacketsLost.Construct(packetsLost);
-            rtt.apply([&s](auto r) { s.mRoundTripTime.Construct(r); });
-            if (!query->report->mRemoteInboundRtpStreamStats.Value()
-                     .AppendElement(s, fallible)) {
-              mozalloc_handle_oom(0);
-            }
-          }
-        }
-        // Then, fill in local side (with cross-link to remote only if present)
-        {
-          RTCOutboundRtpStreamStats s;
-          // TODO Bug 1496533 - use reception time not query time
-          s.mTimestamp.Construct(query->now);
-          s.mId.Construct(localId);
-          s.mType.Construct(RTCStatsType::Outbound_rtp);
-          ssrc.apply([&s](uint32_t aSsrc) { s.mSsrc.Construct(aSsrc); });
-          s.mMediaType.Construct(kind);  // mediaType is the old name for kind.
-          s.mKind.Construct(kind);
-          s.mRemoteId.Construct(remoteId);
-          s.mPacketsSent.Construct(mp.RtpPacketsSent());
-          s.mBytesSent.Construct(mp.RtpBytesSent());
-
-          // Fill in packet type statistics
-          webrtc::RtcpPacketTypeCounter counters;
-          if (mp.Conduit()->GetSendPacketTypeStats(&counters)) {
-            s.mNackCount.Construct(counters.nack_packets);
-            // Fill in video only packet type stats
-            if (asVideo) {
-              s.mFirCount.Construct(counters.fir_packets);
-              s.mPliCount.Construct(counters.pli_packets);
-            }
-          }
-
-          // Lastly, fill in video encoder stats if this is video
-          asVideo.apply([&s](auto conduit) {
-            double framerateMean;
-            double framerateStdDev;
-            double bitrateMean;
-            double bitrateStdDev;
-            uint32_t droppedFrames;
-            uint32_t framesEncoded;
-            Maybe<uint64_t> qpSum;
-            if (conduit->GetVideoEncoderStats(
-                    &framerateMean, &framerateStdDev, &bitrateMean,
-                    &bitrateStdDev, &droppedFrames, &framesEncoded, &qpSum)) {
-              s.mFramerateMean.Construct(framerateMean);
-              s.mFramerateStdDev.Construct(framerateStdDev);
-              s.mBitrateMean.Construct(bitrateMean);
-              s.mBitrateStdDev.Construct(bitrateStdDev);
-              s.mDroppedFrames.Construct(droppedFrames);
-              s.mFramesEncoded.Construct(framesEncoded);
-              qpSum.apply([&s](uint64_t aQp) { s.mQpSum.Construct(aQp); });
-            }
-          });
-          if (!query->report->mOutboundRtpStreamStats.Value().AppendElement(
-                  s, fallible)) {
-            mozalloc_handle_oom(0);
-          }
-        }
-        break;
-      }
-      case MediaPipeline::DirectionType::RECEIVE: {
-        nsString localId = NS_LITERAL_STRING("inbound_rtp_") + idstr;
-        nsString remoteId;
-        Maybe<uint32_t> ssrc;
-        unsigned int ssrcval;
-        if (mp.Conduit()->GetRemoteSSRC(&ssrcval)) {
-          ssrc = Some(ssrcval);
-        }
-        {
-          // First, fill in remote stat with rtcp sender data, if present.
-          uint32_t packetsSent;
-          uint64_t bytesSent;
-          if (mp.Conduit()->GetRTCPSenderReport(&packetsSent, &bytesSent)) {
-            remoteId = NS_LITERAL_STRING("inbound_rtcp_") + idstr;
-            RTCRemoteOutboundRtpStreamStats s;
-            // TODO Bug 1496533 - use reception time not query time
-            s.mTimestamp.Construct(query->now);
-            s.mId.Construct(remoteId);
-            s.mType.Construct(RTCStatsType::Remote_outbound_rtp);
-            ssrc.apply([&s](uint32_t aSsrc) { s.mSsrc.Construct(aSsrc); });
-            s.mMediaType.Construct(
-                kind);  // mediaType is the old name for kind.
-            s.mKind.Construct(kind);
-            s.mLocalId.Construct(localId);
-            s.mPacketsSent.Construct(packetsSent);
-            s.mBytesSent.Construct(bytesSent);
-            if (!query->report->mRemoteOutboundRtpStreamStats.Value()
-                     .AppendElement(s, fallible)) {
-              mozalloc_handle_oom(0);
-            }
-          }
-        }
-        // Then, fill in local side (with cross-link to remote only if present)
-        RTCInboundRtpStreamStats s;
-        s.mTimestamp.Construct(query->now);
-        s.mId.Construct(localId);
-        s.mType.Construct(RTCStatsType::Inbound_rtp);
-        ssrc.apply([&s](uint32_t aSsrc) { s.mSsrc.Construct(aSsrc); });
-        s.mMediaType.Construct(kind);  // mediaType is the old name for kind.
-        s.mKind.Construct(kind);
-        unsigned int jitterMs, packetsLost;
-        if (mp.Conduit()->GetRTPReceiverStats(&jitterMs, &packetsLost)) {
-          s.mJitter.Construct(double(jitterMs) / 1000);
-          s.mPacketsLost.Construct(packetsLost);
-        }
-        if (remoteId.Length()) {
-          s.mRemoteId.Construct(remoteId);
-        }
-        s.mPacketsReceived.Construct(mp.RtpPacketsReceived());
-        s.mBytesReceived.Construct(mp.RtpBytesReceived());
-
-        // Fill in packet type statistics
-        webrtc::RtcpPacketTypeCounter counters;
-        if (mp.Conduit()->GetRecvPacketTypeStats(&counters)) {
-          s.mNackCount.Construct(counters.nack_packets);
-          // Fill in video only packet type stats
-          if (asVideo) {
-            s.mFirCount.Construct(counters.fir_packets);
-            s.mPliCount.Construct(counters.pli_packets);
-          }
-        }
-        // Lastly, fill in video decoder stats if this is video
-        asVideo.apply([&s](auto conduit) {
-          double framerateMean;
-          double framerateStdDev;
-          double bitrateMean;
-          double bitrateStdDev;
-          uint32_t discardedPackets;
-          uint32_t framesDecoded;
-          if (conduit->GetVideoDecoderStats(
-                  &framerateMean, &framerateStdDev, &bitrateMean,
-                  &bitrateStdDev, &discardedPackets, &framesDecoded)) {
-            s.mFramerateMean.Construct(framerateMean);
-            s.mFramerateStdDev.Construct(framerateStdDev);
-            s.mBitrateMean.Construct(bitrateMean);
-            s.mBitrateStdDev.Construct(bitrateStdDev);
-            s.mDiscardedPackets.Construct(discardedPackets);
-            s.mFramesDecoded.Construct(framesDecoded);
-          }
-        });
-        if (!query->report->mInboundRtpStreamStats.Value().AppendElement(
-                s, fallible)) {
-          mozalloc_handle_oom(0);
-        }
-        // Fill in Contributing Source statistics
-        mp.GetContributingSourceStats(
-            localId, query->report->mRtpContributingSourceStats.Value());
-        break;
-      }
-    }
-  }
-
-  std::string transportId;
-  if (!query->grabAllLevels) {
-    transportId = query->transportId;
-  }
-  auto report = std::move(query->report);
-  auto now = query->now;
-
-  return aTransportHandler->GetIceStats(transportId, now, std::move(report))
+  return dom::RTCStatsPromise::All(mThread, promises)
       ->Then(
-          GetMainThreadSerialEventTarget(), __func__,
-          [query = std::move(query)](
-              std::unique_ptr<dom::RTCStatsReportInternal>&& aReport) mutable {
-            query->report = std::move(aReport);
-            return RTCStatsQueryPromise::CreateAndResolve(std::move(query),
-                                                          __func__);
+          mThread, __func__,
+          [report = std::move(report), idGen = mIdGenerator](
+              const nsTArray<UniquePtr<dom::RTCStatsCollection>>&
+                  aStats) mutable {
+            // Rewrite an Optional id
+            auto rewriteId = [&idGen](Optional<nsString>& id) {
+              if (id.WasPassed()) {
+                id.Value() = idGen->Id(id.Value());
+              }
+            };
+
+            // Involves a lot of copying, since webidl dictionaries don't have
+            // move semantics. Oh well.
+            for (const auto& stats : aStats) {
+              for (auto& stat : stats->mIceCandidatePairStats) {
+                rewriteId(stat.mLocalCandidateId);
+                rewriteId(stat.mRemoteCandidateId);
+              };
+              AssignWithOpaqueIds(stats->mIceCandidatePairStats,
+                                  report->mIceCandidatePairStats, idGen);
+
+              AssignWithOpaqueIds(stats->mIceCandidateStats,
+                                  report->mIceCandidateStats, idGen);
+
+              RewriteRemoteIds(stats->mInboundRtpStreamStats, idGen);
+              AssignWithOpaqueIds(stats->mInboundRtpStreamStats,
+                                  report->mInboundRtpStreamStats, idGen);
+
+              RewriteRemoteIds(stats->mOutboundRtpStreamStats, idGen);
+              AssignWithOpaqueIds(stats->mOutboundRtpStreamStats,
+                                  report->mOutboundRtpStreamStats, idGen);
+
+              RewriteLocalIds(stats->mRemoteInboundRtpStreamStats, idGen);
+              AssignWithOpaqueIds(stats->mRemoteInboundRtpStreamStats,
+                                  report->mRemoteInboundRtpStreamStats, idGen);
+
+              RewriteLocalIds(stats->mRemoteOutboundRtpStreamStats, idGen);
+              AssignWithOpaqueIds(stats->mRemoteOutboundRtpStreamStats,
+                                  report->mRemoteOutboundRtpStreamStats, idGen);
+
+              AssignWithOpaqueIds(stats->mRtpContributingSourceStats,
+                                  report->mRtpContributingSourceStats, idGen);
+              AssignWithOpaqueIds(stats->mTrickledIceCandidateStats,
+                                  report->mTrickledIceCandidateStats, idGen);
+              if (!report->mRawLocalCandidates.AppendElements(
+                      stats->mRawLocalCandidates, fallible) ||
+                  !report->mRawRemoteCandidates.AppendElements(
+                      stats->mRawRemoteCandidates, fallible)) {
+                // XXX(Bug 1632090) Instead of extending the array 1-by-1 (which
+                // might involve multiple reallocations) and potentially
+                // crashing here, SetCapacity could be called outside the loop
+                // once.
+                mozalloc_handle_oom(0);
+              }            }
+            return dom::RTCStatsReportPromise::CreateAndResolve(
+                std::move(report), __func__);
           },
-          [](nsresult aError) {
-            return RTCStatsQueryPromise::CreateAndReject(aError, __func__);
+          [](nsresult rv) {
+            return dom::RTCStatsReportPromise::CreateAndReject(rv, __func__);
           });
 }
 
-void PeerConnectionImpl::DeliverStatsReportToPCObserver_m(
-    const std::string& pcHandle, nsresult result,
-    const nsAutoPtr<RTCStatsQuery>& query) {
-  // Is the PeerConnectionImpl still around?
-  PeerConnectionWrapper pcw(pcHandle);
-  if (pcw.impl()) {
-    JSErrorResult rv;
-    if (NS_SUCCEEDED(result)) {
-      pcw.impl()->mPCObserver->OnGetStatsSuccess(*query->report, rv);
-    } else {
-      pcw.impl()->mPCObserver->OnGetStatsError(
-          ObString("Failed to fetch statistics"), rv);
-    }
-
-    if (rv.Failed()) {
-      CSFLogError(LOGTAG, "Error firing stats observer callback");
-    }
-  }
-}
-
 void PeerConnectionImpl::RecordLongtermICEStatistics() {
   WebrtcGlobalInformation::StoreLongTermICEStatistics(*this);
 }
diff --git a/media/webrtc/signaling/src/peerconnection/PeerConnectionImpl.h b/media/webrtc/signaling/src/peerconnection/PeerConnectionImpl.h
index 1359d51903..f392fe1576 100644
--- a/media/webrtc/signaling/src/peerconnection/PeerConnectionImpl.h
+++ b/media/webrtc/signaling/src/peerconnection/PeerConnectionImpl.h
@@ -40,6 +40,8 @@
 #include "VideoSegment.h"
 #include "mozilla/dom/RTCStatsReportBinding.h"
 #include "mozilla/PeerIdentity.h"
+#include "RTCStatsIdGenerator.h"
+#include "RTCStatsReport.h"
 
 namespace test {
 #ifdef USE_FAKE_PCOBSERVER
@@ -54,6 +56,8 @@ struct CandidateInfo;
 class DataChannel;
 class DtlsIdentity;
 class MediaPipeline;
+class MediaPipelineReceive;
+class MediaPipelineTransmit;
 class TransceiverImpl;
 
 namespace dom {
@@ -118,27 +122,6 @@ class PCUuidGenerator : public mozilla::JsepUuidGenerator {
   nsCOMPtr<nsIUUIDGenerator> mGenerator;
 };
 
-// Not an inner class so we can forward declare.
-class RTCStatsQuery {
- public:
-  explicit RTCStatsQuery(bool aInternalStats, bool aRecordTelemetry);
-  RTCStatsQuery(RTCStatsQuery&& aOrig) = default;
-  ~RTCStatsQuery();
-
-  std::unique_ptr<mozilla::dom::RTCStatsReportInternal> report;
-  // A timestamp to help with telemetry.
-  mozilla::TimeStamp iceStartTime;
-
-  bool internalStats;
-  bool recordTelemetry;
-  std::string transportId;
-  bool grabAllLevels;
-  DOMHighResTimeStamp now;
-};
-
-typedef MozPromise<UniquePtr<RTCStatsQuery>, nsresult, true>
-    RTCStatsQueryPromise;
-
 // Enter an API call and check that the state is OK,
 // the PC isn't closed, etc.
 #define PC_AUTO_ENTER_API_CALL(assert_ice_ready)             \
@@ -265,10 +248,7 @@ class PeerConnectionImpl final
     rv = SetRemoteDescription(aAction, NS_ConvertUTF16toUTF8(aSDP).get());
   }
 
-  NS_IMETHODIMP_TO_ERRORRESULT(GetStats, ErrorResult& rv,
-                               mozilla::dom::MediaStreamTrack* aSelector) {
-    rv = GetStats(aSelector);
-  }
+  already_AddRefed<dom::Promise> GetStats(dom::MediaStreamTrack* aSelector);
 
   NS_IMETHODIMP AddIceCandidate(const char* aCandidate, const char* aMid,
                                 const char* aUfrag,
@@ -329,12 +309,13 @@ class PeerConnectionImpl final
   // test-only: called from contributing sources mochitests.
   NS_IMETHODIMP_TO_ERRORRESULT(InsertAudioLevelForContributingSource,
                                ErrorResult& rv,
-                               dom::MediaStreamTrack& aRecvTrack,
-                               unsigned long aSource,
-                               DOMHighResTimeStamp aTimestamp, bool aHasLevel,
-                               uint8_t aLevel) {
-    rv = InsertAudioLevelForContributingSource(aRecvTrack, aSource, aTimestamp,
-                                               aHasLevel, aLevel);
+                               const dom::MediaStreamTrack& aRecvTrack,
+                               const unsigned long aSource,
+                               const DOMHighResTimeStamp aTimestamp,
+                               const unsigned long aRtpTimestamp,
+                               const bool aHasLevel, const uint8_t aLevel) {
+    rv = InsertAudioLevelForContributingSource(
+        aRecvTrack, aSource, aTimestamp, aRtpTimestamp, aHasLevel, aLevel);
   }
 
   // test-only: called from simulcast mochitests.
@@ -474,9 +455,8 @@ class PeerConnectionImpl final
   // initialize telemetry for when calls start
   void startCallTelem();
 
-  RefPtr<RTCStatsQueryPromise> GetStats(dom::MediaStreamTrack* aSelector,
-                                        bool aInternalStats,
-                                        bool aRecordTelemetry);
+  RefPtr<dom::RTCStatsReportPromise> GetStats(dom::MediaStreamTrack* aSelector,
+                                              bool aInternalStats);
 
   // for monitoring changes in track ownership
   // PeerConnectionMedia can't do it because it doesn't know about principals
@@ -490,17 +470,19 @@ class PeerConnectionImpl final
   void DumpPacket_m(size_t level, dom::mozPacketDumpType type, bool sending,
                     UniquePtr<uint8_t[]>& packet, size_t size);
 
+  const dom::RTCStatsTimestampMaker& GetTimestampMaker() const {
+    return mTimestampMaker;
+  }
+
  private:
   virtual ~PeerConnectionImpl();
   PeerConnectionImpl(const PeerConnectionImpl& rhs);
   PeerConnectionImpl& operator=(PeerConnectionImpl);
-  nsresult BuildStatsQuery_m(mozilla::dom::MediaStreamTrack* aSelector,
-                             RTCStatsQuery* query);
-  static RefPtr<RTCStatsQueryPromise> ExecuteStatsQuery_s(
-      UniquePtr<RTCStatsQuery>&& query,
-      const nsTArray<RefPtr<MediaPipeline>>& aPipelines,
-      const RefPtr<MediaTransportHandler>& aTransportHandler);
 
+  RefPtr<dom::RTCStatsPromise> GetReceiverStats(
+      const RefPtr<MediaPipelineReceive>& aPipeline);
+  RefPtr<dom::RTCStatsPromise> GetSenderStats(
+      const RefPtr<MediaPipelineTransmit>& aPipeline);
   nsresult CalculateFingerprint(const std::string& algorithm,
                                 std::vector<uint8_t>* fingerprint) const;
   nsresult ConfigureJsepSessionCodecs();
@@ -523,8 +505,6 @@ class PeerConnectionImpl final
   RefPtr<MediaPipeline> GetMediaPipelineForTrack(
       dom::MediaStreamTrack& aRecvTrack);
 
-  nsresult GetTimeSinceEpoch(DOMHighResTimeStamp* result);
-
   // Shut down media - called on main thread only
   void ShutdownMedia();
 
@@ -545,11 +525,6 @@ class PeerConnectionImpl final
       JsepTransceiver* aJsepTransceiver, dom::MediaStreamTrack* aSendTrack,
       ErrorResult& aRv);
 
-  // Sends an RTCStatsReport to JS. Must run on main thread.
-  static void DeliverStatsReportToPCObserver_m(
-      const std::string& pcHandle, nsresult result,
-      const nsAutoPtr<RTCStatsQuery>& query);
-
   // When ICE completes, we record a bunch of statistics that outlive the
   // PeerConnection. This is just telemetry right now, but this can also
   // include things like dumping the RLogConnector somewhere, saving away
@@ -670,6 +645,10 @@ class PeerConnectionImpl final
   // on the about:webrtc raw candidates table.
   std::vector<std::string> mRawTrickledCandidates;
 
+  dom::RTCStatsTimestampMaker mTimestampMaker;
+
+  RefPtr<RTCStatsIdGenerator> mIdGenerator;
+
  public:
   // these are temporary until the DataChannel Listen/Connect API is removed
   unsigned short listenPort;
diff --git a/media/webrtc/signaling/src/peerconnection/PeerConnectionMedia.cpp b/media/webrtc/signaling/src/peerconnection/PeerConnectionMedia.cpp
index 3e034010c5..3d932f1595 100644
--- a/media/webrtc/signaling/src/peerconnection/PeerConnectionMedia.cpp
+++ b/media/webrtc/signaling/src/peerconnection/PeerConnectionMedia.cpp
@@ -71,7 +71,7 @@ void PeerConnectionMedia::StunAddrsHandler::OnStunAddrsAvailable(
              (int)addrs.Length());
   if (pcm_) {
     pcm_->mStunAddrs = addrs;
-    pcm_->mLocalAddrsCompleted = true;
+    pcm_->mLocalAddrsRequestState = STUN_ADDR_REQUEST_COMPLETE;
     pcm_->FlushIceCtxOperationQueueIfReady();
     // If parent process returns 0 STUN addresses, change ICE connection
     // state to failed.
@@ -90,7 +90,7 @@ PeerConnectionMedia::PeerConnectionMedia(PeerConnectionImpl* parent)
       mSTSThread(mParent->GetSTSThread()),
       mForceProxy(false),
       mStunAddrsRequest(nullptr),
-      mLocalAddrsCompleted(false),
+      mLocalAddrsRequestState(STUN_ADDR_REQUEST_NONE),
       mTargetForDefaultLocalAddressLookupIsSet(false),
       mDestroyed(false) {
   if (XRE_IsContentProcess()) {
@@ -109,10 +109,14 @@ PeerConnectionMedia::~PeerConnectionMedia() {
 }
 
 void PeerConnectionMedia::InitLocalAddrs() {
+  if (mLocalAddrsRequestState == STUN_ADDR_REQUEST_PENDING) {
+    return;
+  }
   if (mStunAddrsRequest) {
+    mLocalAddrsRequestState = STUN_ADDR_REQUEST_PENDING;
     mStunAddrsRequest->SendGetStunAddrs();
   } else {
-    mLocalAddrsCompleted = true;
+    mLocalAddrsRequestState = STUN_ADDR_REQUEST_COMPLETE;
   }
 }
 
@@ -393,8 +397,8 @@ void PeerConnectionMedia::FlushIceCtxOperationQueueIfReady() {
   ASSERT_ON_THREAD(mMainThread);
 
   if (IsIceCtxReady()) {
-    for (auto& mQueuedIceCtxOperation : mQueuedIceCtxOperations) {
-      mQueuedIceCtxOperation->Run();
+    for (auto& queuedIceCtxOperation : mQueuedIceCtxOperations) {
+      queuedIceCtxOperation->Run();
     }
     mQueuedIceCtxOperations.clear();
   }
@@ -414,6 +418,14 @@ void PeerConnectionMedia::PerformOrEnqueueIceCtxOperation(
 void PeerConnectionMedia::GatherIfReady() {
   ASSERT_ON_THREAD(mMainThread);
 
+  // Init local addrs here so that if we re-gather after an ICE restart
+  // resulting from changing WiFi networks, we get new local addrs.
+  // Otherwise, we would reuse the addrs from the original WiFi network
+  // and the ICE restart will fail.
+  if (!mStunAddrs.Length()) {
+    InitLocalAddrs();
+  }
+
   // If we had previously queued gathering or ICE start, unqueue them
   mQueuedIceCtxOperations.clear();
   nsCOMPtr<nsIRunnable> runnable(WrapRunnable(
@@ -583,7 +595,7 @@ nsresult PeerConnectionMedia::AddTransceiver(
     dom::MediaStreamTrack* aSendTrack, const PrincipalHandle& aPrincipalHandle,
     RefPtr<TransceiverImpl>* aTransceiverImpl) {
   if (!mCall) {
-    mCall = WebRtcCallWrapper::Create();
+    mCall = WebRtcCallWrapper::Create(mParent->GetTimestampMaker());
   }
 
   RefPtr<TransceiverImpl> transceiver = new TransceiverImpl(
@@ -615,7 +627,7 @@ nsresult PeerConnectionMedia::AddTransceiver(
 
 void PeerConnectionMedia::GetTransmitPipelinesMatching(
     const MediaStreamTrack* aTrack,
-    nsTArray<RefPtr<MediaPipeline>>* aPipelines) {
+    nsTArray<RefPtr<MediaPipelineTransmit>>* aPipelines) {
   for (RefPtr<TransceiverImpl>& transceiver : mTransceivers) {
     if (transceiver->HasSendTrack(aTrack)) {
       aPipelines->AppendElement(transceiver->GetSendPipeline());
@@ -625,7 +637,7 @@ void PeerConnectionMedia::GetTransmitPipelinesMatching(
 
 void PeerConnectionMedia::GetReceivePipelinesMatching(
     const MediaStreamTrack* aTrack,
-    nsTArray<RefPtr<MediaPipeline>>* aPipelines) {
+    nsTArray<RefPtr<MediaPipelineReceive>>* aPipelines) {
   for (RefPtr<TransceiverImpl>& transceiver : mTransceivers) {
     if (transceiver->HasReceiveTrack(aTrack)) {
       aPipelines->AppendElement(transceiver->GetReceivePipeline());
@@ -636,7 +648,8 @@ void PeerConnectionMedia::GetReceivePipelinesMatching(
 std::string PeerConnectionMedia::GetTransportIdMatching(
     const dom::MediaStreamTrack& aTrack) const {
   for (const RefPtr<TransceiverImpl>& transceiver : mTransceivers) {
-    if (transceiver->HasReceiveTrack(&aTrack)) {
+    if (transceiver->HasReceiveTrack(&aTrack) ||
+        transceiver->HasSendTrack(&aTrack)) {
       return transceiver->GetTransportId();
     }
   }
diff --git a/media/webrtc/signaling/src/peerconnection/PeerConnectionMedia.h b/media/webrtc/signaling/src/peerconnection/PeerConnectionMedia.h
index 6b939268dc..be2f4f1169 100644
--- a/media/webrtc/signaling/src/peerconnection/PeerConnectionMedia.h
+++ b/media/webrtc/signaling/src/peerconnection/PeerConnectionMedia.h
@@ -36,6 +36,8 @@ class PeerConnectionImpl;
 class PeerConnectionMedia;
 class PCUuidGenerator;
 class MediaPipeline;
+class MediaPipelineReceive;
+class MediaPipelineTransmit;
 class MediaPipelineFilter;
 class JsepSession;
 
@@ -60,6 +62,8 @@ class PeerConnectionMedia : public sigslot::has_slots<> {
   nsresult UpdateTransports(const JsepSession& aSession,
                             const bool forceIceTcp);
 
+  void ResetStunAddrsForIceRestart() { mStunAddrs.Clear(); }
+
   // Start ICE checks.
   void StartIceChecks(const JsepSession& session);
 
@@ -87,10 +91,11 @@ class PeerConnectionMedia : public sigslot::has_slots<> {
 
   void GetTransmitPipelinesMatching(
       const dom::MediaStreamTrack* aTrack,
-      nsTArray<RefPtr<MediaPipeline>>* aPipelines);
+      nsTArray<RefPtr<MediaPipelineTransmit>>* aPipelines);
 
-  void GetReceivePipelinesMatching(const dom::MediaStreamTrack* aTrack,
-                                   nsTArray<RefPtr<MediaPipeline>>* aPipelines);
+  void GetReceivePipelinesMatching(
+      const dom::MediaStreamTrack* aTrack,
+      nsTArray<RefPtr<MediaPipelineReceive>>* aPipelines);
 
   std::string GetTransportIdMatching(const dom::MediaStreamTrack& aTrack) const;
 
@@ -188,7 +193,9 @@ class PeerConnectionMedia : public sigslot::has_slots<> {
   void OnCandidateFound_m(const std::string& aTransportId,
                           const CandidateInfo& aCandidateInfo);
 
-  bool IsIceCtxReady() const { return mLocalAddrsCompleted; }
+  bool IsIceCtxReady() const {
+    return mLocalAddrsRequestState == STUN_ADDR_REQUEST_COMPLETE;
+  }
 
   // The parent PC
   PeerConnectionImpl* mParent;
@@ -216,8 +223,13 @@ class PeerConnectionMedia : public sigslot::has_slots<> {
   // Used to cancel incoming stun addrs response
   RefPtr<net::StunAddrsRequestChild> mStunAddrsRequest;
 
+  enum StunAddrRequestState {
+    STUN_ADDR_REQUEST_NONE,
+    STUN_ADDR_REQUEST_PENDING,
+    STUN_ADDR_REQUEST_COMPLETE
+  };
   // Used to track the state of the stun addr IPC request
-  bool mLocalAddrsCompleted;
+  StunAddrRequestState mLocalAddrsRequestState;
 
   // Used to store the result of the stun addr IPC request
   nsTArray<NrIceStunAddr> mStunAddrs;
diff --git a/media/webrtc/signaling/src/peerconnection/RTCStatsIdGenerator.cpp b/media/webrtc/signaling/src/peerconnection/RTCStatsIdGenerator.cpp
new file mode 100644
index 0000000000..4f4b50da1d
--- /dev/null
+++ b/media/webrtc/signaling/src/peerconnection/RTCStatsIdGenerator.cpp
@@ -0,0 +1,32 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "RTCStatsIdGenerator.h"
+#include "mozilla/RandomNum.h"
+#include <iostream>
+namespace mozilla {
+
+RTCStatsIdGenerator::RTCStatsIdGenerator()
+    : mSalt(RandomUint64().valueOr(0xa5a5a5a5)), mCounter(0) {}
+
+nsString RTCStatsIdGenerator::Id(const nsString& aKey) {
+  if (!aKey.Length()) {
+    MOZ_ASSERT(aKey.Length(), "Stats IDs should never be empty.");
+    return aKey;
+  }
+  if (mAllocated.find(aKey) == mAllocated.end()) {
+    mAllocated[aKey] = Generate();
+  }
+  return mAllocated[aKey];
+}
+
+nsString RTCStatsIdGenerator::Generate() {
+  auto random = RandomUint64().valueOr(0x1a22);
+  auto idNum = static_cast<uint32_t>(mSalt ^ ((mCounter++ << 16) | random));
+  nsString id;
+  id.AppendInt(idNum, 16);  // Append as hex
+  return id;
+}
+
+}  // namespace mozilla
diff --git a/media/webrtc/signaling/src/peerconnection/RTCStatsIdGenerator.h b/media/webrtc/signaling/src/peerconnection/RTCStatsIdGenerator.h
new file mode 100644
index 0000000000..84c8530dd8
--- /dev/null
+++ b/media/webrtc/signaling/src/peerconnection/RTCStatsIdGenerator.h
@@ -0,0 +1,27 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef _RTCSTATSIDGENERATOR_H_
+#define _RTCSTATSIDGENERATOR_H_
+
+#include "mozilla/Atomics.h"
+
+namespace mozilla {
+
+class RTCStatsIdGenerator {
+public:
+	RTCStatsIdGenerator();
+	nsString Id(const nsString& aKey);
+	NS_INLINE_DECL_THREADSAFE_REFCOUNTING(RTCStatsIdGenerator);
+private:
+	virtual ~RTCStatsIdGenerator() {};
+	nsString Generate();
+
+	const uint64_t mSalt;
+	uint64_t mCounter;
+	std::map<nsString, nsString> mAllocated;
+};
+
+}
+#endif
diff --git a/media/webrtc/signaling/src/peerconnection/RTCStatsReport.cpp b/media/webrtc/signaling/src/peerconnection/RTCStatsReport.cpp
new file mode 100644
index 0000000000..2a004f40c8
--- /dev/null
+++ b/media/webrtc/signaling/src/peerconnection/RTCStatsReport.cpp
@@ -0,0 +1,74 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+#include "RTCStatsReport.h"
+#include "mozilla/dom/Performance.h"
+#include "nsRFPService.h"
+
+namespace mozilla {
+namespace dom {
+
+RTCStatsTimestampMaker::RTCStatsTimestampMaker(const GlobalObject* aGlobal) {
+  nsCOMPtr<nsPIDOMWindowInner> window;
+  if (aGlobal && (window = do_QueryInterface(aGlobal->GetAsSupports())) &&
+      window->GetPerformance()) {
+    mRandomTimelineSeed = window->GetPerformance()->GetRandomTimelineSeed();
+    mStartWallClock = window->GetPerformance()->TimeOrigin();
+    mStartMonotonic = window->GetPerformance()->CreationTimeStamp();
+  }
+}
+
+DOMHighResTimeStamp RTCStatsTimestampMaker::GetNow() const {
+  // webrtc-pc says to use performance.timeOrigin + performance.now(), but
+  // keeping a Performance object around is difficult because it is
+  // main-thread-only. So, we perform the same calculation here. Note that this
+  // can be very different from the current wall-clock time because of changes
+  // to the wall clock, or monotonic clock drift over long periods of time.
+  TimeStamp nowMonotonic = TimeStamp::NowUnfuzzed();
+  DOMHighResTimeStamp msSinceStart =
+      (nowMonotonic - mStartMonotonic).ToMilliseconds();
+  DOMHighResTimeStamp rawTime = mStartWallClock + msSinceStart;
+  return nsRFPService::ReduceTimePrecisionAsMSecs(rawTime, mRandomTimelineSeed);
+}
+
+NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE(RTCStatsReport, mParent)
+
+NS_IMPL_CYCLE_COLLECTION_ROOT_NATIVE(RTCStatsReport, AddRef)
+NS_IMPL_CYCLE_COLLECTION_UNROOT_NATIVE(RTCStatsReport, Release)
+
+RTCStatsReport::RTCStatsReport(nsPIDOMWindowInner* aParent)
+    : mParent(aParent) {}
+
+/*static*/
+already_AddRefed<RTCStatsReport> RTCStatsReport::Constructor(
+    const GlobalObject& aGlobal) {
+  nsCOMPtr<nsPIDOMWindowInner> window(
+      do_QueryInterface(aGlobal.GetAsSupports()));
+  RefPtr<RTCStatsReport> report(new RTCStatsReport(window));
+  return report.forget();
+}
+
+JSObject* RTCStatsReport::WrapObject(JSContext* aCx,
+                                     JS::Handle<JSObject*> aGivenProto) {
+  return RTCStatsReport_Binding::Wrap(aCx, this, aGivenProto);
+}
+
+void RTCStatsReport::Incorporate(RTCStatsCollection& aStats) {
+  SetRTCStats(aStats.mIceCandidatePairStats);
+  SetRTCStats(aStats.mIceCandidateStats);
+  SetRTCStats(aStats.mInboundRtpStreamStats);
+  SetRTCStats(aStats.mOutboundRtpStreamStats);
+  SetRTCStats(aStats.mRemoteInboundRtpStreamStats);
+  SetRTCStats(aStats.mRemoteOutboundRtpStreamStats);
+  SetRTCStats(aStats.mRtpContributingSourceStats);
+  SetRTCStats(aStats.mTrickledIceCandidateStats);
+}
+
+void RTCStatsReport::Set(const nsAString& aKey, JS::Handle<JSObject*> aValue,
+                         ErrorResult& aRv) {
+  RTCStatsReport_Binding::MaplikeHelpers::Set(this, aKey, aValue, aRv);
+}
+
+}  // namespace dom
+}  // namespace mozilla
diff --git a/media/webrtc/signaling/src/peerconnection/RTCStatsReport.h b/media/webrtc/signaling/src/peerconnection/RTCStatsReport.h
new file mode 100644
index 0000000000..049c404dca
--- /dev/null
+++ b/media/webrtc/signaling/src/peerconnection/RTCStatsReport.h
@@ -0,0 +1,112 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+#ifndef RTCStatsReport_h_
+#define RTCStatsReport_h_
+
+#include "nsWrapperCache.h"
+#include "nsCOMPtr.h"
+
+#include "nsPIDOMWindow.h"               // nsPIDOMWindowInner
+#include "mozilla/dom/ScriptSettings.h"  // AutoEntryScript
+#include "nsIGlobalObject.h"
+#include "js/RootingAPI.h"  // JS::Rooted
+#include "js/Value.h"
+#include "mozilla/ErrorResult.h"
+#include "mozilla/UniquePtr.h"
+#include "prtime.h"  // PR_Now
+#include "mozilla/TimeStamp.h"
+#include "mozilla/dom/RTCStatsReportBinding.h"  // RTCStatsCollection
+
+namespace mozilla {
+namespace dom {
+
+class RTCStatsTimestampMaker {
+ public:
+  RTCStatsTimestampMaker() = default;
+  explicit RTCStatsTimestampMaker(const GlobalObject* aGlobal);
+  DOMHighResTimeStamp GetNow() const;
+
+ private:
+  uint64_t mRandomTimelineSeed = 0;
+  DOMHighResTimeStamp mStartWallClock = (double)PR_Now() / PR_USEC_PER_MSEC;
+  TimeStamp mStartMonotonic = TimeStamp::NowUnfuzzed();
+};
+
+typedef MozPromise<UniquePtr<RTCStatsCollection>, nsresult, true>
+    RTCStatsPromise;
+
+typedef MozPromise<UniquePtr<RTCStatsReportInternal>, nsresult, true>
+    RTCStatsReportPromise;
+
+class RTCStatsReport final : public nsWrapperCache {
+ public:
+  NS_INLINE_DECL_CYCLE_COLLECTING_NATIVE_REFCOUNTING(RTCStatsReport)
+  NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_NATIVE_CLASS(RTCStatsReport)
+
+  explicit RTCStatsReport(nsPIDOMWindowInner* aParent);
+
+  // TODO(bug 1586109): Remove this once we no longer have to create empty
+  // RTCStatsReports from JS.
+  static already_AddRefed<RTCStatsReport> Constructor(
+      const GlobalObject& aGlobal);
+
+  void Incorporate(RTCStatsCollection& aStats);
+
+  nsPIDOMWindowInner* GetParentObject() const { return mParent; }
+
+  JSObject* WrapObject(JSContext* aCx,
+                       JS::Handle<JSObject*> aGivenProto) override;
+
+ private:
+  ~RTCStatsReport() = default;
+  void Set(const nsAString& aKey, JS::Handle<JSObject*> aValue,
+           ErrorResult& aRv);
+
+  template <typename T>
+  nsresult SetRTCStats(Sequence<T>& aValues) {
+    for (T& value : aValues) {
+      nsresult rv = SetRTCStats(value);
+      if (NS_FAILED(rv)) {
+        return rv;
+      }
+    }
+    return NS_OK;
+  }
+
+  // We cannot just declare this as SetRTCStats(RTCStats&), because the
+  // conversion function that ToJSValue uses is non-virtual.
+  template <typename T>
+  nsresult SetRTCStats(T& aValue) {
+    static_assert(std::is_base_of<RTCStats, T>::value,
+                  "SetRTCStats is for setting RTCStats only");
+
+    if (!aValue.mId.WasPassed()) {
+      return NS_OK;
+    }
+
+    const nsString key(aValue.mId.Value());
+
+    // Cargo-culted from dom::Promise; converts aValue to a JSObject
+    AutoEntryScript aes(mParent->AsGlobal()->GetGlobalJSObject(),
+                        "RTCStatsReport::SetRTCStats");
+    JSContext* cx = aes.cx();
+    JS::Rooted<JS::Value> val(cx);
+    if (!ToJSValue(cx, std::forward<T>(aValue), &val)) {
+      return NS_ERROR_FAILURE;
+    }
+    JS::Rooted<JSObject*> jsObject(cx, &val.toObject());
+
+    ErrorResult rv;
+    Set(key, jsObject, rv);
+    return rv.StealNSResult();
+  }
+
+  nsCOMPtr<nsPIDOMWindowInner> mParent;
+};
+
+}  // namespace dom
+}  // namespace mozilla
+
+#endif  // RTCStatsReport_h_
diff --git a/media/webrtc/signaling/src/peerconnection/TransceiverImpl.cpp b/media/webrtc/signaling/src/peerconnection/TransceiverImpl.cpp
index 92160bc934..86cb2f72ad 100644
--- a/media/webrtc/signaling/src/peerconnection/TransceiverImpl.cpp
+++ b/media/webrtc/signaling/src/peerconnection/TransceiverImpl.cpp
@@ -558,11 +558,11 @@ already_AddRefed<dom::MediaStreamTrack> TransceiverImpl::GetReceiveTrack() {
   return do_AddRef(mReceiveTrack);
 }
 
-RefPtr<MediaPipeline> TransceiverImpl::GetSendPipeline() {
+RefPtr<MediaPipelineTransmit> TransceiverImpl::GetSendPipeline() {
   return mTransmitPipeline;
 }
 
-RefPtr<MediaPipeline> TransceiverImpl::GetReceivePipeline() {
+RefPtr<MediaPipelineReceive> TransceiverImpl::GetReceivePipeline() {
   return mReceivePipeline;
 }
 
@@ -982,17 +982,16 @@ void TransceiverImpl::GetRtpSources(
   audio_conduit->GetRtpSources(aTimeNow, outSources);
 }
 
-void TransceiverImpl::InsertAudioLevelForContributingSource(uint32_t aSource,
-                                                            int64_t aTimestamp,
-                                                            bool aHasLevel,
-                                                            uint8_t aLevel) {
+void TransceiverImpl::InsertAudioLevelForContributingSource(
+    const uint32_t aSource, const int64_t aTimestamp,
+    const uint32_t aRtpTimestamp, const bool aHasLevel, const uint8_t aLevel) {
   if (!IsValid() || IsVideo()) {
     return;
   }
   WebrtcAudioConduit* audio_conduit =
       static_cast<WebrtcAudioConduit*>(mConduit.get());
-  audio_conduit->InsertAudioLevelForContributingSource(aSource, aTimestamp,
-                                                       aHasLevel, aLevel);
+  audio_conduit->InsertAudioLevelForContributingSource(
+      aSource, aTimestamp, aRtpTimestamp, aHasLevel, aLevel);
 }
 
 }  // namespace mozilla
diff --git a/media/webrtc/signaling/src/peerconnection/TransceiverImpl.h b/media/webrtc/signaling/src/peerconnection/TransceiverImpl.h
index 236ddd364c..be9110877a 100644
--- a/media/webrtc/signaling/src/peerconnection/TransceiverImpl.h
+++ b/media/webrtc/signaling/src/peerconnection/TransceiverImpl.h
@@ -97,9 +97,9 @@ class TransceiverImpl : public nsISupports {
   bool HasReceiveTrack(const dom::MediaStreamTrack* aReceiveTrack) const;
 
   // TODO: These are for stats; try to find a cleaner way.
-  RefPtr<MediaPipeline> GetSendPipeline();
+  RefPtr<MediaPipelineTransmit> GetSendPipeline();
 
-  RefPtr<MediaPipeline> GetReceivePipeline();
+  RefPtr<MediaPipelineReceive> GetReceivePipeline();
 
   std::string GetTransportId() const {
     return mJsepTransceiver->mTransport.mTransportId;
@@ -120,9 +120,11 @@ class TransceiverImpl : public nsISupports {
                      nsTArray<dom::RTCRtpSourceEntry>& outSources) const;
 
   // test-only: insert fake CSRCs and audio levels for testing
-  void InsertAudioLevelForContributingSource(uint32_t aSource,
-                                             int64_t aTimestamp, bool aHasLevel,
-                                             uint8_t aLevel);
+  void InsertAudioLevelForContributingSource(const uint32_t aSource,
+                                             const int64_t aTimestamp,
+                                             const uint32_t aRtpTimestamp,
+                                             const bool aHasLevel,
+                                             const uint8_t aLevel);
 
   NS_DECL_THREADSAFE_ISUPPORTS
 
diff --git a/media/webrtc/signaling/src/peerconnection/WebrtcGlobalInformation.cpp b/media/webrtc/signaling/src/peerconnection/WebrtcGlobalInformation.cpp
index 4e98474eb0..a40b8dfcb4 100644
--- a/media/webrtc/signaling/src/peerconnection/WebrtcGlobalInformation.cpp
+++ b/media/webrtc/signaling/src/peerconnection/WebrtcGlobalInformation.cpp
@@ -13,6 +13,7 @@
 #include <vector>
 #include <map>
 #include <queue>
+#include <type_traits>
 
 #include "CSFLog.h"
 #include "WebRtcLog.h"
@@ -43,7 +44,6 @@ static const char* wgiLogTag = "WebrtcGlobalInformation";
 namespace mozilla {
 namespace dom {
 
-typedef Vector<nsAutoPtr<RTCStatsQuery>> RTCStatsQueries;
 typedef nsTArray<RTCStatsReportInternal> Stats;
 
 template <class Request, typename Callback, typename Result,
@@ -98,8 +98,7 @@ class RequestManager {
   MOZ_CAN_RUN_SCRIPT
   void Complete() {
     IgnoredErrorResult rv;
-    using RealCallbackType =
-        typename RemovePointer<decltype(mCallback.get())>::Type;
+    using RealCallbackType = std::remove_pointer_t<decltype(mCallback.get())>;
     RefPtr<RealCallbackType> callback(mCallback.get());
     callback->Call(mResult, rv);
 
@@ -150,9 +149,7 @@ class StatsRequest
   const nsString mPcIdFilter;
   explicit StatsRequest(int aId, StatsRequestCallback& aCallback,
                         nsAString& aFilter)
-      : RequestManager(aId, aCallback), mPcIdFilter(aFilter) {
-    mResult.mReports.Construct();
-  }
+      : RequestManager(aId, aCallback), mPcIdFilter(aFilter) {}
 
  private:
   StatsRequest() = delete;
@@ -218,17 +215,18 @@ static PeerConnectionCtx* GetPeerConnectionCtx() {
 }
 
 MOZ_CAN_RUN_SCRIPT
-static void OnStatsReport_m(WebrtcGlobalChild* aThisChild, const int aRequestId,
-                            nsTArray<UniquePtr<RTCStatsQuery>>&& aQueryList) {
+static void OnStatsReport_m(
+    WebrtcGlobalChild* aThisChild, const int aRequestId,
+    nsTArray<UniquePtr<dom::RTCStatsReportInternal>>&& aReports) {
   MOZ_ASSERT(NS_IsMainThread());
 
   if (aThisChild) {
     Stats stats;
 
     // Copy stats generated for the currently active PeerConnections
-    for (auto& query : aQueryList) {
-      if (query) {
-        stats.AppendElement(*query->report);
+    for (auto& report : aReports) {
+      if (report) {
+        stats.AppendElement(*report);
       }
     }
     // Reports saved for closed/destroyed PeerConnections
@@ -253,10 +251,9 @@ static void OnStatsReport_m(WebrtcGlobalChild* aThisChild, const int aRequestId,
     return;
   }
 
-  for (auto& query : aQueryList) {
-    if (query) {
-      if (!request->mResult.mReports.Value().AppendElement(*(query->report),
-                                                           fallible)) {
+  for (auto& report : aReports) {
+    if (report) {
+      if (!request->mResult.mReports.AppendElement(*report, fallible)) {
         mozalloc_handle_oom(0);
       }
     }
@@ -266,7 +263,7 @@ static void OnStatsReport_m(WebrtcGlobalChild* aThisChild, const int aRequestId,
   auto ctx = PeerConnectionCtx::GetInstance();
   if (ctx) {
     for (auto&& pc : ctx->mStatsForClosedPeerConnections) {
-      if (!request->mResult.mReports.Value().AppendElement(pc, fallible)) {
+      if (!request->mResult.mReports.AppendElement(pc, fallible)) {
         // XXX(Bug 1632090) Instead of extending the array 1-by-1 (which might
         // involve multiple reallocations) and potentially crashing here,
         // SetCapacity could be called outside the loop once.
@@ -319,7 +316,7 @@ static void RunStatsQuery(
     const std::map<const std::string, PeerConnectionImpl*>& aPeerConnections,
     const nsAString& aPcIdFilter, WebrtcGlobalChild* aThisChild,
     const int aRequestId) {
-  nsTArray<RefPtr<RTCStatsQueryPromise>> promises;
+  nsTArray<RefPtr<RTCStatsReportPromise>> promises;
 
   for (auto& idAndPc : aPeerConnections) {
     MOZ_ASSERT(idAndPc.second);
@@ -328,31 +325,31 @@ static void RunStatsQuery(
         aPcIdFilter.EqualsASCII(pc.GetIdAsAscii().c_str())) {
       if (pc.HasMedia()) {
         promises.AppendElement(
-            pc.GetStats(nullptr, true, false)
+            pc.GetStats(nullptr, true)
                 ->Then(
                     GetMainThreadSerialEventTarget(), __func__,
-                    [=](UniquePtr<RTCStatsQuery>&& aQuery) {
-                      return RTCStatsQueryPromise::CreateAndResolve(
-                          std::move(aQuery), __func__);
+                    [=](UniquePtr<dom::RTCStatsReportInternal>&& aReport) {
+                      return RTCStatsReportPromise::CreateAndResolve(
+                          std::move(aReport), __func__);
                     },
                     [=](nsresult aError) {
                       // Ignore errors! Just resolve with a nullptr.
-                      return RTCStatsQueryPromise::CreateAndResolve(
-                          UniquePtr<RTCStatsQuery>(), __func__);
+                      return RTCStatsReportPromise::CreateAndResolve(
+                          UniquePtr<dom::RTCStatsReportInternal>(), __func__);
                     }));
       }
     }
   }
 
-  RTCStatsQueryPromise::All(GetMainThreadSerialEventTarget(), promises)
+  RTCStatsReportPromise::All(GetMainThreadSerialEventTarget(), promises)
       ->Then(
           GetMainThreadSerialEventTarget(), __func__,
           // MOZ_CAN_RUN_SCRIPT_BOUNDARY because we're going to run that
           // function async anyway.
-          [aThisChild,
-           aRequestId](nsTArray<UniquePtr<RTCStatsQuery>>&& aQueries)
+          [aThisChild, aRequestId](
+              nsTArray<UniquePtr<dom::RTCStatsReportInternal>>&& aReports)
               MOZ_CAN_RUN_SCRIPT_BOUNDARY {
-                OnStatsReport_m(aThisChild, aRequestId, std::move(aQueries));
+                OnStatsReport_m(aThisChild, aRequestId, std::move(aReports));
               },
           [=](nsresult) { MOZ_CRASH(); });
 }
@@ -641,7 +638,7 @@ mozilla::ipc::IPCResult WebrtcGlobalParent::RecvGetStatsResult(
   }
 
   for (auto& s : Stats) {
-    if (!request->mResult.mReports.Value().AppendElement(s, fallible)) {
+    if (!request->mResult.mReports.AppendElement(s, fallible)) {
       CSFLogError(LOGTAG, "Out of memory");
       return IPC_FAIL_NO_REASON(this);
     }
@@ -827,222 +824,71 @@ MOZ_IMPLICIT WebrtcGlobalChild::~WebrtcGlobalChild() {
   MOZ_COUNT_DTOR(WebrtcGlobalChild);
 }
 
-struct StreamResult {
-  StreamResult() : candidateTypeBitpattern(0), streamSucceeded(false) {}
-  uint32_t candidateTypeBitpattern;
-  bool streamSucceeded;
-};
-
-static uint32_t GetCandidateIpAndTransportMask(
-    const RTCIceCandidateStats* cand) {
-  enum {
-    CANDIDATE_BITMASK_UDP = 1,
-    CANDIDATE_BITMASK_TCP = 1 << 1,
-    CANDIDATE_BITMASK_IPV6 = 1 << 2,
-  };
-
-  uint32_t res = 0;
-
-  nsAutoCString transport;
-  // prefer relay transport for local relay candidates
-  if (cand->mRelayProtocol.WasPassed()) {
-    transport.Assign(NS_ConvertUTF16toUTF8(cand->mRelayProtocol.Value()));
-  } else {
-    transport.Assign(NS_ConvertUTF16toUTF8(cand->mProtocol.Value()));
-  }
-  if (transport == kNrIceTransportUdp) {
-    res |= CANDIDATE_BITMASK_UDP;
-  } else if (transport == kNrIceTransportTcp) {
-    res |= CANDIDATE_BITMASK_TCP;
-  }
-
-  if (cand->mAddress.Value().FindChar(':') != -1) {
-    res |= CANDIDATE_BITMASK_IPV6;
-  }
-
-  return res;
-};
-
-static void StoreLongTermICEStatisticsImpl_m(nsresult result,
-                                             RTCStatsQuery* query) {
+static void StoreLongTermICEStatisticsImpl_m(RTCStatsReportInternal* report) {
   using namespace Telemetry;
 
-  if (NS_FAILED(result) || !query->report->mIceCandidateStats.WasPassed()) {
-    return;
-  }
+  report->mClosed = true;
 
-  query->report->mClosed.Construct(true);
-
-  // TODO(bcampen@mozilla.com): Do we need to watch out for cases where the
-  // components within a stream didn't have the same types of relayed
-  // candidates? I have a feeling that late trickle could cause this, but right
-  // now we don't have enough information to detect it (we would need to know
-  // the ICE component id for each candidate pair and candidate)
-
-  std::map<std::string, StreamResult> streamResults;
-
-  // Build list of streams, and whether or not they failed.
-  for (size_t i = 0; i < query->report->mIceCandidatePairStats.Value().Length();
-       ++i) {
-    const RTCIceCandidatePairStats& pair =
-        query->report->mIceCandidatePairStats.Value()[i];
-
-    if (!pair.mState.WasPassed() || !pair.mTransportId.WasPassed()) {
-      MOZ_CRASH();
+  for (const auto& outboundRtpStats : report->mOutboundRtpStreamStats) {
+    bool isVideo = (outboundRtpStats.mId.Value().Find("video") != -1);
+    if (!isVideo) {
       continue;
     }
-
-    // Note: we use NrIceMediaStream's name for the
-    // RTCIceCandidatePairStats tranportId
-    std::string streamId(
-        NS_ConvertUTF16toUTF8(pair.mTransportId.Value()).get());
-
-    streamResults[streamId].streamSucceeded |=
-        pair.mState.Value() == RTCStatsIceCandidatePairState::Succeeded;
+    if (outboundRtpStats.mBitrateMean.WasPassed()) {
+      Accumulate(WEBRTC_VIDEO_ENCODER_BITRATE_AVG_PER_CALL_KBPS,
+                 uint32_t(outboundRtpStats.mBitrateMean.Value() / 1000));
+    }
+    if (outboundRtpStats.mBitrateStdDev.WasPassed()) {
+      Accumulate(WEBRTC_VIDEO_ENCODER_BITRATE_STD_DEV_PER_CALL_KBPS,
+                 uint32_t(outboundRtpStats.mBitrateStdDev.Value() / 1000));
+    }
+    if (outboundRtpStats.mFramerateMean.WasPassed()) {
+      Accumulate(WEBRTC_VIDEO_ENCODER_FRAMERATE_AVG_PER_CALL,
+                 uint32_t(outboundRtpStats.mFramerateMean.Value()));
+    }
+    if (outboundRtpStats.mFramerateStdDev.WasPassed()) {
+      Accumulate(WEBRTC_VIDEO_ENCODER_FRAMERATE_10X_STD_DEV_PER_CALL,
+                 uint32_t(outboundRtpStats.mFramerateStdDev.Value() * 10));
+    }
+    if (outboundRtpStats.mDroppedFrames.WasPassed() &&
+        report->mCallDurationMs.WasPassed()) {
+      double mins = report->mCallDurationMs.Value() / (1000 * 60);
+      if (mins > 0) {
+        Accumulate(
+            WEBRTC_VIDEO_ENCODER_DROPPED_FRAMES_PER_CALL_FPM,
+            uint32_t(double(outboundRtpStats.mDroppedFrames.Value()) / mins));
+      }
+    }
   }
 
-  for (size_t i = 0; i < query->report->mIceCandidateStats.Value().Length();
-       ++i) {
-    const RTCIceCandidateStats& cand =
-        query->report->mIceCandidateStats.Value()[i];
-
-    if (!cand.mType.WasPassed() || !cand.mCandidateType.WasPassed() ||
-        !cand.mProtocol.WasPassed() || !cand.mAddress.WasPassed() ||
-        !cand.mTransportId.WasPassed()) {
-      // Crash on debug, ignore this candidate otherwise.
-      MOZ_CRASH();
+  for (const auto& inboundRtpStats : report->mInboundRtpStreamStats) {
+    bool isVideo = (inboundRtpStats.mId.Value().Find("video") != -1);
+    if (!isVideo) {
       continue;
     }
-
-    /* The bitmask after examaning a candidate should look like this:
-     * REMOTE_GATHERED_HOST_UDP = 1,
-     * REMOTE_GATHERED_HOST_TCP = 1 << 1,
-     * REMOTE_GATHERED_HOST_IPV6 = 1 << 2,
-     * REMOTE_GATHERED_SERVER_REFLEXIVE_UDP = 1 << 3,
-     * REMOTE_GATHERED_SERVER_REFLEXIVE_TCP = 1 << 4,
-     * REMOTE_GATHERED_SERVER_REFLEXIVE_IPV6 = 1 << 5,
-     * REMOTE_GATHERED_TURN_UDP = 1 << 6,
-     * REMOTE_GATHERED_TURN_TCP = 1 << 7, // dummy place holder
-     * REMOTE_GATHERED_TURN_IPV6 = 1 << 8,
-     * REMOTE_GATHERED_PEER_REFLEXIVE_UDP = 1 << 9,
-     * REMOTE_GATHERED_PEER_REFLEXIVE_TCP = 1 << 10,
-     * REMOTE_GATHERED_PEER_REFLEXIVE_IPV6 = 1 << 11,
-     * LOCAL_GATHERED_HOST_UDP = 1 << 16,
-     * LOCAL_GATHERED_HOST_TCP = 1 << 17,
-     * LOCAL_GATHERED_HOST_IPV6 = 1 << 18,
-     * LOCAL_GATHERED_SERVER_REFLEXIVE_UDP = 1 << 19,
-     * LOCAL_GATHERED_SERVER_REFLEXIVE_TCP = 1 << 20,
-     * LOCAL_GATHERED_SERVER_REFLEXIVE_IPV6 = 1 << 21,
-     * LOCAL_GATHERED_TURN_UDP = 1 << 22,
-     * LOCAL_GATHERED_TURN_TCP = 1 << 23,
-     * LOCAL_GATHERED_TURN_IPV6 = 1 << 24,
-     * LOCAL_GATHERED_PEERREFLEXIVE_UDP = 1 << 25,
-     * LOCAL_GATHERED_PEERREFLEXIVE_TCP = 1 << 26,
-     * LOCAL_GATHERED_PEERREFLEXIVE_IPV6 = 1 << 27,
-     *
-     * This results in following shift values
-     */
-    static const uint32_t kLocalShift = 16;
-    static const uint32_t kSrflxShift = 3;
-    static const uint32_t kRelayShift = 6;
-    static const uint32_t kPrflxShift = 9;
-
-    uint32_t candBitmask = GetCandidateIpAndTransportMask(&cand);
-
-    // Note: shift values need to result in the above enum table
-    if (cand.mType.Value() == RTCStatsType::Local_candidate) {
-      candBitmask <<= kLocalShift;
+    if (inboundRtpStats.mBitrateMean.WasPassed()) {
+      Accumulate(WEBRTC_VIDEO_DECODER_BITRATE_AVG_PER_CALL_KBPS,
+                 uint32_t(inboundRtpStats.mBitrateMean.Value() / 1000));
     }
-
-    if (cand.mCandidateType.Value() == RTCIceCandidateType::Srflx) {
-      candBitmask <<= kSrflxShift;
-    } else if (cand.mCandidateType.Value() == RTCIceCandidateType::Relay) {
-      candBitmask <<= kRelayShift;
-    } else if (cand.mCandidateType.Value() == RTCIceCandidateType::Prflx) {
-      candBitmask <<= kPrflxShift;
+    if (inboundRtpStats.mBitrateStdDev.WasPassed()) {
+      Accumulate(WEBRTC_VIDEO_DECODER_BITRATE_STD_DEV_PER_CALL_KBPS,
+                 uint32_t(inboundRtpStats.mBitrateStdDev.Value() / 1000));
     }
-
-    // Note: this is not a "transport", this is really a stream ID. This is just
-    // the way the stats API is standardized right now.
-    // Very confusing.
-    std::string streamId(
-        NS_ConvertUTF16toUTF8(cand.mTransportId.Value()).get());
-
-    streamResults[streamId].candidateTypeBitpattern |= candBitmask;
-  }
-
-  for (auto& streamResult : streamResults) {
-    Telemetry::RecordWebrtcIceCandidates(
-        streamResult.second.candidateTypeBitpattern,
-        streamResult.second.streamSucceeded);
-  }
-
-  // Beyond ICE, accumulate telemetry for various PER_CALL settings here.
-
-  if (query->report->mOutboundRtpStreamStats.WasPassed()) {
-    auto& array = query->report->mOutboundRtpStreamStats.Value();
-    for (decltype(array.Length()) i = 0; i < array.Length(); i++) {
-      auto& s = array[i];
-      bool isVideo = (s.mId.Value().Find("video") != -1);
-      if (!isVideo) {
-        continue;
-      }
-      if (s.mBitrateMean.WasPassed()) {
-        Accumulate(WEBRTC_VIDEO_ENCODER_BITRATE_AVG_PER_CALL_KBPS,
-                   uint32_t(s.mBitrateMean.Value() / 1000));
-      }
-      if (s.mBitrateStdDev.WasPassed()) {
-        Accumulate(WEBRTC_VIDEO_ENCODER_BITRATE_STD_DEV_PER_CALL_KBPS,
-                   uint32_t(s.mBitrateStdDev.Value() / 1000));
-      }
-      if (s.mFramerateMean.WasPassed()) {
-        Accumulate(WEBRTC_VIDEO_ENCODER_FRAMERATE_AVG_PER_CALL,
-                   uint32_t(s.mFramerateMean.Value()));
-      }
-      if (s.mFramerateStdDev.WasPassed()) {
-        Accumulate(WEBRTC_VIDEO_ENCODER_FRAMERATE_10X_STD_DEV_PER_CALL,
-                   uint32_t(s.mFramerateStdDev.Value() * 10));
-      }
-      if (s.mDroppedFrames.WasPassed() && !query->iceStartTime.IsNull()) {
-        double mins = (TimeStamp::Now() - query->iceStartTime).ToSeconds() / 60;
-        if (mins > 0) {
-          Accumulate(WEBRTC_VIDEO_ENCODER_DROPPED_FRAMES_PER_CALL_FPM,
-                     uint32_t(double(s.mDroppedFrames.Value()) / mins));
-        }
-      }
+    if (inboundRtpStats.mFramerateMean.WasPassed()) {
+      Accumulate(WEBRTC_VIDEO_DECODER_FRAMERATE_AVG_PER_CALL,
+                 uint32_t(inboundRtpStats.mFramerateMean.Value()));
     }
-  }
-
-  if (query->report->mInboundRtpStreamStats.WasPassed()) {
-    auto& array = query->report->mInboundRtpStreamStats.Value();
-    for (decltype(array.Length()) i = 0; i < array.Length(); i++) {
-      auto& s = array[i];
-      bool isVideo = (s.mId.Value().Find("video") != -1);
-      if (!isVideo) {
-        continue;
-      }
-      if (s.mBitrateMean.WasPassed()) {
-        Accumulate(WEBRTC_VIDEO_DECODER_BITRATE_AVG_PER_CALL_KBPS,
-                   uint32_t(s.mBitrateMean.Value() / 1000));
-      }
-      if (s.mBitrateStdDev.WasPassed()) {
-        Accumulate(WEBRTC_VIDEO_DECODER_BITRATE_STD_DEV_PER_CALL_KBPS,
-                   uint32_t(s.mBitrateStdDev.Value() / 1000));
-      }
-      if (s.mFramerateMean.WasPassed()) {
-        Accumulate(WEBRTC_VIDEO_DECODER_FRAMERATE_AVG_PER_CALL,
-                   uint32_t(s.mFramerateMean.Value()));
-      }
-      if (s.mFramerateStdDev.WasPassed()) {
-        Accumulate(WEBRTC_VIDEO_DECODER_FRAMERATE_10X_STD_DEV_PER_CALL,
-                   uint32_t(s.mFramerateStdDev.Value() * 10));
-      }
-      if (s.mDiscardedPackets.WasPassed() && !query->iceStartTime.IsNull()) {
-        double mins = (TimeStamp::Now() - query->iceStartTime).ToSeconds() / 60;
-        if (mins > 0) {
-          Accumulate(WEBRTC_VIDEO_DECODER_DISCARDED_PACKETS_PER_CALL_PPM,
-                     uint32_t(double(s.mDiscardedPackets.Value()) / mins));
-        }
+    if (inboundRtpStats.mFramerateStdDev.WasPassed()) {
+      Accumulate(WEBRTC_VIDEO_DECODER_FRAMERATE_10X_STD_DEV_PER_CALL,
+                 uint32_t(inboundRtpStats.mFramerateStdDev.Value() * 10));
+    }
+    if (inboundRtpStats.mDiscardedPackets.WasPassed() &&
+        report->mCallDurationMs.WasPassed()) {
+      double mins = report->mCallDurationMs.Value() / (1000 * 60);
+      if (mins > 0) {
+        Accumulate(
+            WEBRTC_VIDEO_DECODER_DISCARDED_PACKETS_PER_CALL_PPM,
+            uint32_t(double(inboundRtpStats.mDiscardedPackets.Value()) / mins));
       }
     }
   }
@@ -1051,8 +897,7 @@ static void StoreLongTermICEStatisticsImpl_m(nsresult result,
 
   PeerConnectionCtx* ctx = GetPeerConnectionCtx();
   if (ctx) {
-    if (!ctx->mStatsForClosedPeerConnections.AppendElement(*query->report,
-                                                           fallible)) {
+    if (!ctx->mStatsForClosedPeerConnections.AppendElement(*report, fallible)) {
       mozalloc_handle_oom(0);
     }
   }
@@ -1066,15 +911,13 @@ void WebrtcGlobalInformation::StoreLongTermICEStatistics(
     return;
   }
 
-  aPc.GetStats(nullptr, true, false)
+  aPc.GetStats(nullptr, true)
       ->Then(
           GetMainThreadSerialEventTarget(), __func__,
-          [=](UniquePtr<RTCStatsQuery>&& aQuery) {
-            StoreLongTermICEStatisticsImpl_m(NS_OK, aQuery.get());
+          [=](UniquePtr<dom::RTCStatsReportInternal>&& aReport) {
+            StoreLongTermICEStatisticsImpl_m(aReport.get());
           },
-          [=](nsresult aError) {
-            StoreLongTermICEStatisticsImpl_m(aError, nullptr);
-          });
+          [=](nsresult aError) {});
 }
 
 }  // namespace dom
diff --git a/media/webrtc/signaling/src/peerconnection/moz.build b/media/webrtc/signaling/src/peerconnection/moz.build
index 2da76116b3..378dec5124 100644
--- a/media/webrtc/signaling/src/peerconnection/moz.build
+++ b/media/webrtc/signaling/src/peerconnection/moz.build
@@ -28,6 +28,8 @@ UNIFIED_SOURCES += [
     'PeerConnectionCtx.cpp',
     'PeerConnectionImpl.cpp',
     'PeerConnectionMedia.cpp',
+    'RTCStatsIdGenerator.cpp',
+    'RTCStatsReport.cpp',
     'TransceiverImpl.cpp',
     'WebrtcGlobalInformation.cpp',
 ]
diff --git a/memory/replace/dmd/DMD.cpp b/memory/replace/dmd/DMD.cpp
index 365fe8e6c9..b601c5d794 100644
--- a/memory/replace/dmd/DMD.cpp
+++ b/memory/replace/dmd/DMD.cpp
@@ -516,64 +516,13 @@ class AutoBlockIntercepts {
 // Location service
 //---------------------------------------------------------------------------
 
-class StringTable {
- public:
-  StringTable() : mSet(64) {}
-
-  const char* Intern(const char* aString) {
-    StringHashSet::AddPtr p = mSet.lookupForAdd(aString);
-    if (p) {
-      return *p;
-    }
-
-    const char* newString = InfallibleAllocPolicy::strdup_(aString);
-    MOZ_ALWAYS_TRUE(mSet.add(p, newString));
-    return newString;
-  }
-
-  size_t SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const {
-    size_t n = 0;
-    n += mSet.shallowSizeOfExcludingThis(aMallocSizeOf);
-    for (auto iter = mSet.iter(); !iter.done(); iter.next()) {
-      n += aMallocSizeOf(iter.get());
-    }
-    return n;
-  }
-
- private:
-  struct StringHasher {
-    typedef const char* Lookup;
-
-    static mozilla::HashNumber hash(const char* const& aS) {
-      return HashString(aS);
-    }
-
-    static bool match(const char* const& aA, const char* const& aB) {
-      return strcmp(aA, aB) == 0;
-    }
-  };
-
-  typedef mozilla::HashSet<const char*, StringHasher, InfallibleAllocPolicy>
-      StringHashSet;
-
-  StringHashSet mSet;
-};
-
-class StringAlloc {
- public:
-  static char* copy(const char* aString) {
-    return InfallibleAllocPolicy::strdup_(aString);
-  }
-  static void free(char* aString) { InfallibleAllocPolicy::free_(aString); }
-};
-
 struct DescribeCodeAddressLock {
   static void Unlock() { gStateLock->Unlock(); }
   static void Lock() { gStateLock->Lock(); }
   static bool IsLocked() { return gStateLock->IsLocked(); }
 };
 
-typedef CodeAddressService<StringTable, StringAlloc, DescribeCodeAddressLock>
+typedef CodeAddressService<InfallibleAllocPolicy, DescribeCodeAddressLock>
     CodeAddressService;
 
 //---------------------------------------------------------------------------
diff --git a/mfbt/Algorithm.h b/mfbt/Algorithm.h
index 2fd483215e..bae9900350 100644
--- a/mfbt/Algorithm.h
+++ b/mfbt/Algorithm.h
@@ -7,6 +7,11 @@
 #ifndef mozilla_Algorithm_h
 #define mozilla_Algorithm_h
 
+#include "mozilla/Result.h"
+
+#include <iterator>
+#include <type_traits>
+
 namespace mozilla {
 
 // Returns true if all elements in the range [aFirst, aLast)
@@ -21,6 +26,89 @@ constexpr bool AllOf(Iter aFirst, Iter aLast, Pred aPred) {
   return true;
 }
 
+namespace detail {
+template <typename Transform, typename SrcIter>
+using ArrayElementTransformType = typename std::invoke_result_t<
+    Transform, typename std::iterator_traits<SrcIter>::reference>;
+
+template <typename Transform, typename SrcIter>
+struct TransformTraits {
+  using result_type = ArrayElementTransformType<Transform, SrcIter>;
+
+  using result_ok_type = typename result_type::ok_type;
+  using result_err_type = typename result_type::err_type;
+};
+}  // namespace detail
+
+// An algorithm similar to TransformAbortOnErr combined with a condition that
+// allows to skip elements. At most std::distance(aIter, aEnd) elements will be
+// inserted into aDst.
+//
+// Type requirements, in addition to those specified in TransformAbortOnErr:
+// - Cond must be compatible with signature
+//   bool (const SrcIter::value_type&)
+template <typename SrcIter, typename DstIter, typename Cond, typename Transform>
+Result<Ok,
+       typename detail::TransformTraits<Transform, SrcIter>::result_err_type>
+TransformIfAbortOnErr(SrcIter aIter, SrcIter aEnd, DstIter aDst, Cond aCond,
+                      Transform aTransform) {
+  for (; aIter != aEnd; ++aIter) {
+    if (!aCond(static_cast<std::add_const_t<
+                   typename std::iterator_traits<SrcIter>::value_type>&>(
+            *aIter))) {
+      continue;
+    }
+
+    auto res = aTransform(*aIter);
+    if (res.isErr()) {
+      return Err(res.unwrapErr());
+    }
+
+    *aDst++ = res.unwrap();
+  }
+  return Ok{};
+}
+
+template <typename SrcRange, typename DstIter, typename Cond,
+          typename Transform>
+auto TransformIfAbortOnErr(SrcRange& aRange, DstIter aDst, Cond aCond,
+                           Transform aTransform) {
+  using std::begin;
+  using std::end;
+  return TransformIfAbortOnErr(begin(aRange), end(aRange), aDst, aCond,
+                               aTransform);
+}
+
+// An algorithm similar to std::transform, adapted to error handling based on
+// mozilla::Result<V, E>. It iterates through the input range [aIter, aEnd) and
+// inserts the result of applying aTransform to each element into aDst, if
+// aTransform returns a success result. On the first error result, iterating is
+// aborted, and the error result is returned as an overall result. If all
+// transformations return a success result, Ok is returned as an overall result.
+//
+// Type requirements:
+// - SrcIter must be an InputIterator.
+// - DstIter must be an OutputIterator.
+// - Transform must be compatible with signature
+//   Result<DstIter::value_type, E> (SrcIter::reference)
+template <typename SrcIter, typename DstIter, typename Transform>
+Result<Ok,
+       typename detail::TransformTraits<Transform, SrcIter>::result_err_type>
+TransformAbortOnErr(SrcIter aIter, SrcIter aEnd, DstIter aDst,
+                    Transform aTransform) {
+  return TransformIfAbortOnErr(
+      aIter, aEnd, aDst, [](const auto&) { return true; }, aTransform);
+}
+
+template <typename SrcRange, typename DstIter, typename Transform>
+auto TransformAbortOnErr(SrcRange& aRange, DstIter aDst, Transform aTransform) {
+  using std::begin;
+  using std::end;
+  return TransformIfAbortOnErr(
+      begin(aRange), end(aRange), aDst, [](const auto&) { return true; },
+      aTransform);
+}
+
 }  // namespace mozilla
 
 #endif  // mozilla_Algorithm_h
diff --git a/mfbt/AlreadyAddRefed.h b/mfbt/AlreadyAddRefed.h
index 1f4f7e6e40..2719d243d7 100644
--- a/mfbt/AlreadyAddRefed.h
+++ b/mfbt/AlreadyAddRefed.h
@@ -7,9 +7,10 @@
 #ifndef AlreadyAddRefed_h
 #define AlreadyAddRefed_h
 
+#include <utility>
+
 #include "mozilla/Assertions.h"
 #include "mozilla/Attributes.h"
-#include "mozilla/Move.h"
 
 namespace mozilla {
 
diff --git a/mfbt/Array.h b/mfbt/Array.h
index f2f92404fb..2e75641425 100644
--- a/mfbt/Array.h
+++ b/mfbt/Array.h
@@ -7,21 +7,25 @@
 #ifndef mozilla_Array_h
 #define mozilla_Array_h
 
+#include <stddef.h>
+
+#include <iterator>
+#include <ostream>
+#include <utility>
+
 #include "mozilla/Assertions.h"
 #include "mozilla/Attributes.h"
-#include "mozilla/Move.h"
-#include "mozilla/ReverseIterator.h"
-
-#include <ostream>
-#include <stddef.h>
 
 namespace mozilla {
 
-template <typename T, size_t Length>
+template <typename T, size_t _Length>
 class Array {
-  T mArr[Length];
+  T mArr[_Length];
 
  public:
+  using ElementType = T;
+  static constexpr size_t Length = _Length;
+
   Array() {}
 
   template <typename... Args>
@@ -53,16 +57,16 @@ class Array {
 
   typedef T* iterator;
   typedef const T* const_iterator;
-  typedef ReverseIterator<T*> reverse_iterator;
-  typedef ReverseIterator<const T*> const_reverse_iterator;
+  typedef std::reverse_iterator<T*> reverse_iterator;
+  typedef std::reverse_iterator<const T*> const_reverse_iterator;
 
   // Methods for range-based for loops.
   iterator begin() { return mArr; }
-  const_iterator begin() const { return mArr; }
-  const_iterator cbegin() const { return begin(); }
+  constexpr const_iterator begin() const { return mArr; }
+  constexpr const_iterator cbegin() const { return begin(); }
   iterator end() { return mArr + Length; }
-  const_iterator end() const { return mArr + Length; }
-  const_iterator cend() const { return end(); }
+  constexpr const_iterator end() const { return mArr + Length; }
+  constexpr const_iterator cend() const { return end(); }
 
   // Methods for reverse iterating.
   reverse_iterator rbegin() { return reverse_iterator(end()); }
diff --git a/mfbt/ArrayUtils.h b/mfbt/ArrayUtils.h
index 24beba5c3a..c0b20b5a64 100644
--- a/mfbt/ArrayUtils.h
+++ b/mfbt/ArrayUtils.h
@@ -16,6 +16,7 @@
 #include <stddef.h>
 
 #ifdef __cplusplus
+#  include <type_traits>
 
 #  include "mozilla/Alignment.h"
 #  include "mozilla/Array.h"
@@ -99,8 +100,7 @@ bool ArrayEqual(const T* const a, const U* const b, const size_t n) {
 
 namespace detail {
 
-template <typename AlignType, typename Pointee,
-          typename = EnableIf<!IsVoid<AlignType>::value>>
+template <typename AlignType, typename Pointee, typename = void>
 struct AlignedChecker {
   static void test(const Pointee* aPtr) {
     MOZ_ASSERT((uintptr_t(aPtr) % MOZ_ALIGNOF(AlignType)) == 0,
@@ -109,7 +109,8 @@ struct AlignedChecker {
 };
 
 template <typename AlignType, typename Pointee>
-struct AlignedChecker<AlignType, Pointee> {
+struct AlignedChecker<AlignType, Pointee,
+                      std::enable_if_t<IsVoid<AlignType>::value>> {
   static void test(const Pointee* aPtr) {}
 };
 
@@ -129,9 +130,9 @@ struct AlignedChecker<AlignType, Pointee> {
  * particular alignment).
  */
 template <typename T, typename U>
-inline typename EnableIf<IsSame<T, U>::value || std::is_base_of<T, U>::value ||
-                             IsVoid<T>::value,
-                         bool>::Type
+inline std::enable_if_t<IsSame<T, U>::value || std::is_base_of<T, U>::value ||
+                            IsVoid<T>::value,
+                        bool>
 IsInRange(const T* aPtr, const U* aBegin, const U* aEnd) {
   MOZ_ASSERT(aBegin <= aEnd);
   detail::AlignedChecker<U, T>::test(aPtr);
diff --git a/mfbt/Assertions.h b/mfbt/Assertions.h
index c6fa3a7bb6..f8d275b727 100644
--- a/mfbt/Assertions.h
+++ b/mfbt/Assertions.h
@@ -413,15 +413,14 @@ MOZ_END_EXTERN_C
  */
 
 #ifdef __cplusplus
-#  include "mozilla/TypeTraits.h"
 #  include <type_traits>
 namespace mozilla {
 namespace detail {
 
 template <typename T>
 struct AssertionConditionType {
-  typedef typename RemoveReference<T>::Type ValueT;
-  static_assert(!IsArray<ValueT>::value,
+  using ValueT = std::remove_reference_t<T>;
+  static_assert(!std::is_array_v<ValueT>,
                 "Expected boolean assertion condition, got an array or a "
                 "string!");
   static_assert(!std::is_function_v<ValueT>,
diff --git a/mfbt/Atomics.h b/mfbt/Atomics.h
index 3617a31435..0771a82ff9 100644
--- a/mfbt/Atomics.h
+++ b/mfbt/Atomics.h
@@ -374,9 +374,8 @@ class Atomic;
  * swap method is provided.
  */
 template <typename T, MemoryOrdering Order>
-class Atomic<
-    T, Order,
-    typename EnableIf<std::is_integral_v<T> && !IsSame<T, bool>::value>::Type>
+class Atomic<T, Order,
+             std::enable_if_t<std::is_integral_v<T> && !IsSame<T, bool>::value>>
     : public detail::AtomicBaseIncDec<T, Order> {
   typedef typename detail::AtomicBaseIncDec<T, Order> Base;
 
@@ -446,7 +445,7 @@ class Atomic<T*, Order> : public detail::AtomicBaseIncDec<T*, Order> {
  * The atomic store and load operations and the atomic swap method is provided.
  */
 template <typename T, MemoryOrdering Order>
-class Atomic<T, Order, typename EnableIf<std::is_enum_v<T>>::Type>
+class Atomic<T, Order, std::enable_if_t<std::is_enum_v<T>>>
     : public detail::AtomicBase<T, Order> {
   typedef typename detail::AtomicBase<T, Order> Base;
 
@@ -503,10 +502,14 @@ class Atomic<bool, Order> : protected detail::AtomicBase<uint32_t, Order> {
   Atomic(Atomic& aOther) = delete;
 };
 
-// If you want to atomically swap two atomic values, use exchange().
-template <typename T, MemoryOrdering Order>
-void Swap(Atomic<T, Order>&, Atomic<T, Order>&) = delete;
-
 }  // namespace mozilla
 
+namespace std {
+
+// If you want to atomically swap two atomic values, use exchange().
+template <typename T, mozilla::MemoryOrdering Order>
+void swap(mozilla::Atomic<T, Order>&, mozilla::Atomic<T, Order>&) = delete;
+
+}  // namespace std
+
 #endif /* mozilla_Atomics_h */
diff --git a/mfbt/Buffer.h b/mfbt/Buffer.h
index 2f2f3bc263..5220fc5253 100644
--- a/mfbt/Buffer.h
+++ b/mfbt/Buffer.h
@@ -6,6 +6,8 @@
 #define mozilla_Buffer_h
 
 #include <algorithm>
+#include <iterator>
+
 #include "mozilla/Maybe.h"
 #include "mozilla/Span.h"
 #include "mozilla/UniquePtr.h"
@@ -138,8 +140,8 @@ class Buffer final {
 
   typedef T* iterator;
   typedef const T* const_iterator;
-  typedef ReverseIterator<T*> reverse_iterator;
-  typedef ReverseIterator<const T*> const_reverse_iterator;
+  typedef std::reverse_iterator<T*> reverse_iterator;
+  typedef std::reverse_iterator<const T*> const_reverse_iterator;
 
   // Methods for range-based for loops.
   iterator begin() { return mData.get(); }
diff --git a/mfbt/BufferList.h b/mfbt/BufferList.h
index 300fce694f..2b3aad5d1d 100644
--- a/mfbt/BufferList.h
+++ b/mfbt/BufferList.h
@@ -5,16 +5,18 @@
 #ifndef mozilla_BufferList_h
 #define mozilla_BufferList_h
 
+#include <string.h>
+
 #include <algorithm>
+#include <utility>
+
 #include "mozilla/AllocPolicy.h"
 #include "mozilla/Maybe.h"
 #include "mozilla/MemoryReporting.h"
-#include "mozilla/Move.h"
 #include "mozilla/ScopeExit.h"
-#include "mozilla/Types.h"
 #include "mozilla/TypeTraits.h"
+#include "mozilla/Types.h"
 #include "mozilla/Vector.h"
-#include <string.h>
 
 // BufferList represents a sequence of buffers of data. A BufferList can choose
 // to own its buffers or not. The class handles writing to the buffers,
diff --git a/mfbt/CompactPair.h b/mfbt/CompactPair.h
new file mode 100644
index 0000000000..668d9022a5
--- /dev/null
+++ b/mfbt/CompactPair.h
@@ -0,0 +1,234 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/* A class holding a pair of objects that tries to conserve storage space. */
+
+#ifndef mozilla_CompactPair_h
+#define mozilla_CompactPair_h
+
+#include <type_traits>
+#include <tuple>
+#include <utility>
+
+#include "mozilla/Attributes.h"
+
+namespace mozilla {
+
+namespace detail {
+
+enum StorageType { AsBase, AsMember };
+
+// Optimize storage using the Empty Base Optimization -- that empty base classes
+// don't take up space -- to optimize size when one or the other class is
+// stateless and can be used as a base class.
+//
+// The extra conditions on storage for B are necessary so that CompactPairHelper
+// won't ambiguously inherit from either A or B, such that one or the other base
+// class would be inaccessible.
+template <typename A, typename B,
+          detail::StorageType =
+              std::is_empty_v<A> ? detail::AsBase : detail::AsMember,
+          detail::StorageType = std::is_empty_v<B> &&
+                                        !std::is_base_of<A, B>::value &&
+                                        !std::is_base_of<B, A>::value
+                                    ? detail::AsBase
+                                    : detail::AsMember>
+struct CompactPairHelper;
+
+template <typename A, typename B>
+struct CompactPairHelper<A, B, AsMember, AsMember> {
+ protected:
+  template <typename... AArgs, std::size_t... AIndexes, typename... BArgs,
+            std::size_t... BIndexes>
+  CompactPairHelper(std::tuple<AArgs...>& aATuple,
+                    std::tuple<BArgs...>& aBTuple,
+                    std::index_sequence<AIndexes...>,
+                    std::index_sequence<BIndexes...>)
+      : mFirstA(std::forward<AArgs>(std::get<AIndexes>(aATuple))...),
+        mSecondB(std::forward<BArgs>(std::get<BIndexes>(aBTuple))...) {}
+
+ public:
+  template <typename AArg, typename BArg>
+  CompactPairHelper(AArg&& aA, BArg&& aB)
+      : mFirstA(std::forward<AArg>(aA)), mSecondB(std::forward<BArg>(aB)) {}
+
+  A& first() { return mFirstA; }
+  const A& first() const { return mFirstA; }
+  B& second() { return mSecondB; }
+  const B& second() const { return mSecondB; }
+
+  void swap(CompactPairHelper& aOther) {
+    std::swap(mFirstA, aOther.mFirstA);
+    std::swap(mSecondB, aOther.mSecondB);
+  }
+
+ private:
+  A mFirstA;
+  B mSecondB;
+};
+
+template <typename A, typename B>
+struct CompactPairHelper<A, B, AsMember, AsBase> : private B {
+ protected:
+  template <typename... AArgs, std::size_t... AIndexes, typename... BArgs,
+            std::size_t... BIndexes>
+  CompactPairHelper(std::tuple<AArgs...>& aATuple,
+                    std::tuple<BArgs...>& aBTuple,
+                    std::index_sequence<AIndexes...>,
+                    std::index_sequence<BIndexes...>)
+      : B(std::forward<BArgs>(std::get<BIndexes>(aBTuple))...),
+        mFirstA(std::forward<AArgs>(std::get<AIndexes>(aATuple))...) {}
+
+ public:
+  template <typename AArg, typename BArg>
+  CompactPairHelper(AArg&& aA, BArg&& aB)
+      : B(std::forward<BArg>(aB)), mFirstA(std::forward<AArg>(aA)) {}
+
+  A& first() { return mFirstA; }
+  const A& first() const { return mFirstA; }
+  B& second() { return *this; }
+  const B& second() const { return *this; }
+
+  void swap(CompactPairHelper& aOther) {
+    std::swap(mFirstA, aOther.mFirstA);
+    std::swap(static_cast<B&>(*this), static_cast<B&>(aOther));
+  }
+
+ private:
+  A mFirstA;
+};
+
+template <typename A, typename B>
+struct CompactPairHelper<A, B, AsBase, AsMember> : private A {
+ protected:
+  template <typename... AArgs, std::size_t... AIndexes, typename... BArgs,
+            std::size_t... BIndexes>
+  CompactPairHelper(std::tuple<AArgs...>& aATuple,
+                    std::tuple<BArgs...>& aBTuple,
+                    std::index_sequence<AIndexes...>,
+                    std::index_sequence<BIndexes...>)
+      : A(std::forward<AArgs>(std::get<AIndexes>(aATuple))...),
+        mSecondB(std::forward<BArgs>(std::get<BIndexes>(aBTuple))...) {}
+
+ public:
+  template <typename AArg, typename BArg>
+  CompactPairHelper(AArg&& aA, BArg&& aB)
+      : A(std::forward<AArg>(aA)), mSecondB(std::forward<BArg>(aB)) {}
+
+  A& first() { return *this; }
+  const A& first() const { return *this; }
+  B& second() { return mSecondB; }
+  const B& second() const { return mSecondB; }
+
+  void swap(CompactPairHelper& aOther) {
+    std::swap(static_cast<A&>(*this), static_cast<A&>(aOther));
+    std::swap(mSecondB, aOther.mSecondB);
+  }
+
+ private:
+  B mSecondB;
+};
+
+template <typename A, typename B>
+struct CompactPairHelper<A, B, AsBase, AsBase> : private A, private B {
+ protected:
+  template <typename... AArgs, std::size_t... AIndexes, typename... BArgs,
+            std::size_t... BIndexes>
+  CompactPairHelper(std::tuple<AArgs...>& aATuple,
+                    std::tuple<BArgs...>& aBTuple,
+                    std::index_sequence<AIndexes...>,
+                    std::index_sequence<BIndexes...>)
+      : A(std::forward<AArgs>(std::get<AIndexes>(aATuple))...),
+        B(std::forward<BArgs>(std::get<BIndexes>(aBTuple))...) {}
+
+ public:
+  template <typename AArg, typename BArg>
+  CompactPairHelper(AArg&& aA, BArg&& aB)
+      : A(std::forward<AArg>(aA)), B(std::forward<BArg>(aB)) {}
+
+  A& first() { return static_cast<A&>(*this); }
+  const A& first() const { return static_cast<A&>(*this); }
+  B& second() { return static_cast<B&>(*this); }
+  const B& second() const { return static_cast<B&>(*this); }
+
+  void swap(CompactPairHelper& aOther) {
+    std::swap(static_cast<A&>(*this), static_cast<A&>(aOther));
+    std::swap(static_cast<B&>(*this), static_cast<B&>(aOther));
+  }
+};
+
+}  // namespace detail
+
+/**
+ * CompactPair is the logical concatenation of an instance of A with an instance
+ * B. Space is conserved when possible.  Neither A nor B may be a final class.
+ *
+ * In general if space conservation is not critical is preferred to use
+ * std::pair.
+ *
+ * It's typically clearer to have individual A and B member fields.  Except if
+ * you want the space-conserving qualities of CompactPair, you're probably
+ * better off not using this!
+ *
+ * No guarantees are provided about the memory layout of A and B, the order of
+ * initialization or destruction of A and B, and so on.  (This is approximately
+ * required to optimize space usage.)  The first/second names are merely
+ * conceptual!
+ */
+template <typename A, typename B>
+struct CompactPair : private detail::CompactPairHelper<A, B> {
+  typedef typename detail::CompactPairHelper<A, B> Base;
+
+  using Base::Base;
+
+  template <typename... AArgs, typename... BArgs>
+  CompactPair(std::piecewise_construct_t, std::tuple<AArgs...> aFirst,
+              std::tuple<BArgs...> aSecond)
+      : Base(aFirst, aSecond, std::index_sequence_for<AArgs...>(),
+             std::index_sequence_for<BArgs...>()) {}
+
+  CompactPair(CompactPair&& aOther) = default;
+  CompactPair(const CompactPair& aOther) = default;
+
+  CompactPair& operator=(CompactPair&& aOther) = default;
+  CompactPair& operator=(const CompactPair& aOther) = default;
+
+  /** The A instance. */
+  using Base::first;
+  /** The B instance. */
+  using Base::second;
+
+  /** Swap this pair with another pair. */
+  void swap(CompactPair& aOther) { Base::swap(aOther); }
+};
+
+/**
+ * MakeCompactPair allows you to construct a CompactPair instance using type
+ * inference. A call like this:
+ *
+ *   MakeCompactPair(Foo(), Bar())
+ *
+ * will return a CompactPair<Foo, Bar>.
+ */
+template <typename A, typename B>
+CompactPair<std::remove_cv_t<std::remove_reference_t<A>>,
+            std::remove_cv_t<std::remove_reference_t<B>>>
+MakeCompactPair(A&& aA, B&& aB) {
+  return CompactPair<std::remove_cv_t<std::remove_reference_t<A>>,
+                     std::remove_cv_t<std::remove_reference_t<B>>>(
+      std::forward<A>(aA), std::forward<B>(aB));
+}
+
+}  // namespace mozilla
+
+namespace std {
+
+template <typename A, class B>
+void swap(mozilla::CompactPair<A, B>& aX, mozilla::CompactPair<A, B>& aY) {
+  aX.swap(aY);
+}
+
+}  // namespace std
+
+#endif /* mozilla_CompactPair_h */
diff --git a/mfbt/DebugOnly.h b/mfbt/DebugOnly.h
index cbab14bdcb..b0c3a93b40 100644
--- a/mfbt/DebugOnly.h
+++ b/mfbt/DebugOnly.h
@@ -12,6 +12,8 @@
 
 #include "mozilla/Attributes.h"
 
+#include <utility>
+
 namespace mozilla {
 
 /**
@@ -40,12 +42,17 @@ class MOZ_STACK_CLASS DebugOnly {
   T value;
 
   DebugOnly() = default;
+  MOZ_IMPLICIT DebugOnly(T&& aOther) : value(std::move(aOther)) {}
   MOZ_IMPLICIT DebugOnly(const T& aOther) : value(aOther) {}
   DebugOnly(const DebugOnly& aOther) : value(aOther.value) {}
   DebugOnly& operator=(const T& aRhs) {
     value = aRhs;
     return *this;
   }
+  DebugOnly& operator=(T&& aRhs) {
+    value = std::move(aRhs);
+    return *this;
+  }
 
   void operator++(int) { value++; }
   void operator--(int) { value--; }
@@ -67,6 +74,8 @@ class MOZ_STACK_CLASS DebugOnly {
   MOZ_IMPLICIT DebugOnly(const T&) {}
   DebugOnly(const DebugOnly&) {}
   DebugOnly& operator=(const T&) { return *this; }
+  MOZ_IMPLICIT DebugOnly(T&&) {}
+  DebugOnly& operator=(T&&) { return *this; }
   void operator++(int) {}
   void operator--(int) {}
   DebugOnly& operator+=(const T&) { return *this; }
diff --git a/mfbt/EnumeratedArray.h b/mfbt/EnumeratedArray.h
index 6c29987873..8ddce6994e 100644
--- a/mfbt/EnumeratedArray.h
+++ b/mfbt/EnumeratedArray.h
@@ -7,8 +7,9 @@
 #ifndef mozilla_EnumeratedArray_h
 #define mozilla_EnumeratedArray_h
 
+#include <utility>
+
 #include "mozilla/Array.h"
-#include "mozilla/Move.h"
 
 namespace mozilla {
 
diff --git a/mfbt/FunctionRef.h b/mfbt/FunctionRef.h
index db2169c09c..34e89dc7a8 100644
--- a/mfbt/FunctionRef.h
+++ b/mfbt/FunctionRef.h
@@ -15,6 +15,7 @@
 
 #include <cstddef>      // std::nullptr_t
 #include <type_traits>  // std::{declval,integral_constant}, std::is_{convertible,same,void}_v, std::{enable_if,remove_reference,remove_cv}_t
+#include <utility>      // std::forward
 
 // This concept and its implementation are substantially inspired by foonathan's
 // prior art:
@@ -133,7 +134,7 @@ class FunctionRef<Ret(Params...)> {
   static Ret CallFunctionPointer(const Payload& aPayload,
                                  Params... aParams) noexcept {
     auto func = reinterpret_cast<RealFuncPtr>(aPayload.mFuncPtr);
-    return static_cast<Ret>(func(static_cast<Params>(aParams)...));
+    return static_cast<Ret>(func(std::forward<Params>(aParams)...));
   }
 
   template <typename Ret2, typename... Params2>
@@ -176,6 +177,11 @@ class FunctionRef<Ret(Params...)> {
   MOZ_IMPLICIT FunctionRef(Callable& aCallable) noexcept
       : mAdaptor([](const Payload& aPayload, Params... aParams) {
           auto& func = *static_cast<Callable*>(aPayload.mObject);
+          // Unable to use std::forward here due to llvm windows bug
+          // https://bugs.llvm.org/show_bug.cgi?id=28299
+          //
+          // This prevents use of move-only arguments for functors and lambdas.
+          // Move only arguments can be used when using function pointers
           return static_cast<Ret>(func(static_cast<Params>(aParams)...));
         }) {
     ::new (KnownNotNull, &mPayload.mObject) void*(&aCallable);
@@ -206,7 +212,7 @@ class FunctionRef<Ret(Params...)> {
 
   /** Call the callable stored in this with the given arguments. */
   Ret operator()(Params... params) const {
-    return mAdaptor(mPayload, static_cast<Params>(params)...);
+    return mAdaptor(mPayload, std::forward<Params>(params)...);
   }
 
   /** Return true iff this wasn't created from |nullptr|. */
diff --git a/mfbt/GuardObjects.h b/mfbt/GuardObjects.h
index d0cae94730..2d12dfc5e3 100644
--- a/mfbt/GuardObjects.h
+++ b/mfbt/GuardObjects.h
@@ -8,9 +8,10 @@
 #define mozilla_GuardObjects_h
 
 #include "mozilla/Assertions.h"
-#include "mozilla/Move.h"
 #include "mozilla/Types.h"
 
+#include <utility>
+
 #ifdef __cplusplus
 
 #  ifdef DEBUG
diff --git a/mfbt/HashFunctions.h b/mfbt/HashFunctions.h
index 342437418d..c28e10deba 100644
--- a/mfbt/HashFunctions.h
+++ b/mfbt/HashFunctions.h
@@ -177,7 +177,7 @@ inline HashNumber AddUintptrToHash<8>(HashNumber aHash, uintptr_t aValue) {
  * convert to uint32_t, data pointers, and function pointers.
  */
 template <typename T, bool TypeIsNotIntegral = !std::is_integral_v<T>,
-          typename U = typename mozilla::EnableIf<TypeIsNotIntegral>::Type>
+          typename U = std::enable_if_t<TypeIsNotIntegral>>
 MOZ_MUST_USE inline HashNumber AddToHash(HashNumber aHash, T aA) {
   /*
    * Try to convert |A| to uint32_t implicitly.  If this works, great.  If not,
@@ -202,8 +202,7 @@ MOZ_MUST_USE inline HashNumber AddToHash(HashNumber aHash, A* aA) {
 // types are treated the same as 64-bit pointers, and smaller integral types are
 // first implicitly converted to 32 bits and then passed to AddUintptrToHash()
 // to be hashed.
-template <typename T,
-          typename U = typename mozilla::EnableIf<std::is_integral_v<T>>::Type>
+template <typename T, typename U = std::enable_if_t<std::is_integral_v<T>>>
 MOZ_MUST_USE constexpr HashNumber AddToHash(HashNumber aHash, T aA) {
   return detail::AddUintptrToHash<sizeof(T)>(aHash, aA);
 }
diff --git a/mfbt/HashTable.h b/mfbt/HashTable.h
index 94fd5ee520..33fb10af44 100644
--- a/mfbt/HashTable.h
+++ b/mfbt/HashTable.h
@@ -1038,11 +1038,15 @@ class HashTableEntry {
   void destroy() { destroyStoredT(); }
 
   void swap(HashTableEntry* aOther, bool aIsLive) {
+    // This allows types to use Argument-Dependent-Lookup, and thus use a custom
+    // std::swap, which is needed by types like JS::Heap and such.
+    using std::swap;
+
     if (this == aOther) {
       return;
     }
     if (aIsLive) {
-      Swap(*valuePtr(), *aOther->valuePtr());
+      swap(*valuePtr(), *aOther->valuePtr());
     } else {
       *aOther->valuePtr() = std::move(*valuePtr());
       destroy();
@@ -1094,7 +1098,7 @@ class EntrySlot {
 
   void swap(EntrySlot& aOther) {
     mEntry->swap(aOther.mEntry, aOther.isLive());
-    Swap(*mKeyHash, *aOther.mKeyHash);
+    std::swap(*mKeyHash, *aOther.mKeyHash);
   }
 
   T& get() const { return mEntry->get(); }
diff --git a/mfbt/IntegerRange.h b/mfbt/IntegerRange.h
index 7c898da990..eb0a0ca2e0 100644
--- a/mfbt/IntegerRange.h
+++ b/mfbt/IntegerRange.h
@@ -9,8 +9,8 @@
 
 #include "mozilla/Assertions.h"
 #include "mozilla/ReverseIterator.h"
-#include "mozilla/TypeTraits.h"
 
+#include <iterator>
 #include <type_traits>
 
 namespace mozilla {
@@ -20,6 +20,18 @@ namespace detail {
 template <typename IntTypeT>
 class IntegerIterator {
  public:
+  // It is disputable whether these type definitions are correct, since
+  // operator* doesn't return a reference at all. Also, the iterator_category
+  // can be at most std::input_iterator_tag (rather than
+  // std::bidrectional_iterator_tag, as it might seem), because it is a stashing
+  // iterator. See also, e.g.,
+  // https://stackoverflow.com/questions/50909701/what-should-be-iterator-category-for-a-stashing-iterator
+  using value_type = const IntTypeT;
+  using pointer = const value_type*;
+  using reference = const value_type&;
+  using difference_type = std::make_signed_t<IntTypeT>;
+  using iterator_category = std::input_iterator_tag;
+
   template <typename IntType>
   explicit IntegerIterator(IntType aCurrent) : mCurrent(aCurrent) {}
 
@@ -27,6 +39,10 @@ class IntegerIterator {
   explicit IntegerIterator(const IntegerIterator<IntType>& aOther)
       : mCurrent(aOther.mCurrent) {}
 
+  // This intentionally returns a value rather than a reference, to make
+  // mozilla::ReverseIterator work with it. Still, std::reverse_iterator cannot
+  // be used with IntegerIterator because it still is a "stashing iterator". See
+  // Bug 1175485.
   IntTypeT operator*() const { return mCurrent; }
 
   /* Increment and decrement operators */
@@ -129,9 +145,9 @@ class IntegerRange {
   const_iterator cbegin() const { return begin(); }
   iterator end() const { return iterator(mEnd); }
   const_iterator cend() const { return end(); }
-  reverse_iterator rbegin() const { return reverse_iterator(mEnd); }
+  reverse_iterator rbegin() const { return reverse_iterator(iterator(mEnd)); }
   const_reverse_iterator crbegin() const { return rbegin(); }
-  reverse_iterator rend() const { return reverse_iterator(mBegin); }
+  reverse_iterator rend() const { return reverse_iterator(iterator(mBegin)); }
   const_reverse_iterator crend() const { return rend(); }
 
  private:
diff --git a/mfbt/LinkedList.h b/mfbt/LinkedList.h
index 7d97a98eb3..cc8a325def 100644
--- a/mfbt/LinkedList.h
+++ b/mfbt/LinkedList.h
@@ -62,10 +62,11 @@
 #ifndef mozilla_LinkedList_h
 #define mozilla_LinkedList_h
 
+#include <utility>
+
 #include "mozilla/Assertions.h"
 #include "mozilla/Attributes.h"
 #include "mozilla/MemoryReporting.h"
-#include "mozilla/Move.h"
 #include "mozilla/RefPtr.h"
 
 #ifdef __cplusplus
@@ -399,6 +400,12 @@ class LinkedList {
     Type mCurrent;
 
    public:
+    using iterator_category = std::forward_iterator_tag;
+    using value_type = T;
+    using difference_type = std::ptrdiff_t;
+    using pointer = T*;
+    using reference = T&;
+
     explicit Iterator(Type aCurrent) : mCurrent(aCurrent) {}
 
     Type operator*() const { return mCurrent; }
@@ -425,10 +432,15 @@ class LinkedList {
   }
 
   ~LinkedList() {
-    MOZ_ASSERT(isEmpty(),
-               "failing this assertion means this LinkedList's creator is "
-               "buggy: it should have removed all this list's elements before "
-               "the list's destruction");
+#  ifdef DEBUG
+    if (!isEmpty()) {
+      MOZ_CRASH_UNSAFE_PRINTF(
+          "%s has a buggy user: "
+          "it should have removed all this list's elements before "
+          "the list's destruction",
+          __PRETTY_FUNCTION__);
+    }
+#  endif
   }
 
   /*
@@ -485,6 +497,13 @@ class LinkedList {
    */
   bool isEmpty() const { return !sentinel.isInList(); }
 
+  /**
+   * Returns whether the given element is in the list.
+   */
+  bool contains(ConstRawType aElm) const {
+    return std::find(begin(), end(), aElm) != end();
+  }
+
   /*
    * Remove all the elements from the list.
    *
@@ -496,6 +515,11 @@ class LinkedList {
     }
   }
 
+  /**
+   * Return the length of elements in the list.
+   */
+  size_t length() const { return std::distance(begin(), end()); }
+
   /*
    * Allow range-based iteration:
    *
diff --git a/mfbt/MathAlgorithms.h b/mfbt/MathAlgorithms.h
index 45f0fc1ba6..cb36a211e7 100644
--- a/mfbt/MathAlgorithms.h
+++ b/mfbt/MathAlgorithms.h
@@ -66,8 +66,8 @@ struct AllowDeprecatedAbs<long> : TrueType {};
 // DO NOT USE DeprecatedAbs.  It exists only until its callers can be converted
 // to Abs below, and it will be removed when all callers have been changed.
 template <typename T>
-inline typename mozilla::EnableIf<detail::AllowDeprecatedAbs<T>::value, T>::Type
-DeprecatedAbs(const T aValue) {
+inline std::enable_if_t<detail::AllowDeprecatedAbs<T>::value, T> DeprecatedAbs(
+    const T aValue) {
   // The absolute value of the smallest possible value of a signed-integer type
   // won't fit in that type (on twos-complement systems -- and we're blithely
   // assuming we're on such systems, for the non-<stdint.h> types listed above),
@@ -109,11 +109,13 @@ struct AbsReturnTypeFixed<int64_t> {
   typedef uint64_t Type;
 };
 
-template <typename T>
+template <typename T, typename = void>
 struct AbsReturnType : AbsReturnTypeFixed<T> {};
 
-template <>
-struct AbsReturnType<char> : EnableIf<char(-1) < char(0), unsigned char> {};
+template <typename T>
+struct AbsReturnType<T, std::enable_if_t<std::is_same_v<T, char> && char(-1) < char(0)>> {
+  using Type = unsigned char;
+};
 template <>
 struct AbsReturnType<signed char> {
   typedef unsigned char Type;
diff --git a/mfbt/Maybe.h b/mfbt/Maybe.h
index 2d8ba87eb3..0fcd0aa721 100644
--- a/mfbt/Maybe.h
+++ b/mfbt/Maybe.h
@@ -7,19 +7,19 @@
 #ifndef mozilla_Maybe_h
 #define mozilla_Maybe_h
 
+#include <new>  // for placement new
+#include <ostream>
+#include <type_traits>
+#include <utility>
+
 #include "mozilla/Alignment.h"
 #include "mozilla/Assertions.h"
 #include "mozilla/Attributes.h"
 #include "mozilla/MemoryChecking.h"
-#include "mozilla/Move.h"
 #include "mozilla/OperatorNewExtensions.h"
 #include "mozilla/Poison.h"
 #include "mozilla/TypeTraits.h"
 
-#include <new>  // for placement new
-#include <ostream>
-#include <type_traits>
-
 class nsCycleCollectionTraversalCallback;
 
 template <typename T>
@@ -83,9 +83,9 @@ struct OutOfLinePoisoner {
 template <typename T>
 inline void PoisonObject(T* p) {
   const uintptr_t POISON = mozPoisonValue();
-  Conditional<(sizeof(T) <= 8 * sizeof(POISON)),
-              InlinePoisoner<0, sizeof(T) / sizeof(POISON)>,
-              OutOfLinePoisoner<sizeof(T)>>::Type::poison(p, POISON);
+  std::conditional_t<(sizeof(T) <= 8 * sizeof(POISON)),
+                     InlinePoisoner<0, sizeof(T) / sizeof(POISON)>,
+                     OutOfLinePoisoner<sizeof(T)>>::poison(p, POISON);
 }
 
 template <typename T>
@@ -95,15 +95,22 @@ struct MaybePoisoner {
   static void poison(void* aPtr) {
 #ifdef MOZ_DIAGNOSTIC_ASSERT_ENABLED
     if (N >= sizeof(uintptr_t)) {
-      PoisonObject(static_cast<typename RemoveCV<T>::Type*>(aPtr));
+      PoisonObject(static_cast<std::remove_cv_t<T>*>(aPtr));
     }
 #endif
     MOZ_MAKE_MEM_UNDEFINED(aPtr, N);
   }
 };
 
+template <typename T>
+constexpr bool IsTriviallyDestructibleAndCopyable =
+    std::is_trivially_destructible_v<T> &&
+    (std::is_trivially_copy_constructible_v<T> ||
+     !std::is_copy_constructible_v<T>);
+
 template <typename T,
-          bool TriviallyCopyable = std::is_trivially_copy_constructible_v<T>,
+          bool TriviallyDestructibleAndCopyable =
+              IsTriviallyDestructibleAndCopyable<T>,
           bool Copyable = std::is_copy_constructible_v<T>,
           bool Movable = std::is_move_constructible_v<T>>
 class Maybe_CopyMove_Enabler;
@@ -119,16 +126,19 @@ class Maybe_CopyMove_Enabler;
     return downcast(*this).template operator=<T>(downcast(aOther));         \
   }
 
-#define MOZ_MAYBE_MOVE_OPS()                                                   \
-  Maybe_CopyMove_Enabler(Maybe_CopyMove_Enabler&& aOther) {                    \
-    if (downcast(aOther).isSome()) {                                           \
-      downcast(*this).emplace(std::move(*downcast(aOther)));                   \
-      downcast(aOther).reset();                                                \
-    }                                                                          \
-  }                                                                            \
-                                                                               \
-  Maybe_CopyMove_Enabler& operator=(Maybe_CopyMove_Enabler&& aOther) {         \
-    return downcast(*this).template operator=<T>(std::move(downcast(aOther))); \
+#define MOZ_MAYBE_MOVE_OPS()                                            \
+  constexpr Maybe_CopyMove_Enabler(Maybe_CopyMove_Enabler&& aOther) {   \
+    if (downcast(aOther).isSome()) {                                    \
+      downcast(*this).emplace(std::move(*downcast(aOther)));            \
+      downcast(aOther).reset();                                         \
+    }                                                                   \
+  }                                                                     \
+                                                                        \
+  constexpr Maybe_CopyMove_Enabler& operator=(                          \
+      Maybe_CopyMove_Enabler&& aOther) {                                \
+    downcast(*this).template operator=<T>(std::move(downcast(aOther))); \
+                                                                        \
+    return *this;                                                       \
   }
 
 #define MOZ_MAYBE_DOWNCAST()                                          \
@@ -159,6 +169,25 @@ class Maybe_CopyMove_Enabler<T, true, true, true> {
   MOZ_MAYBE_DOWNCAST()
 };
 
+template <typename T>
+class Maybe_CopyMove_Enabler<T, true, false, true> {
+ public:
+  Maybe_CopyMove_Enabler() = default;
+
+  Maybe_CopyMove_Enabler(const Maybe_CopyMove_Enabler&) = delete;
+  Maybe_CopyMove_Enabler& operator=(const Maybe_CopyMove_Enabler&) = delete;
+  constexpr Maybe_CopyMove_Enabler(Maybe_CopyMove_Enabler&& aOther) {
+    downcast(aOther).reset();
+  }
+  constexpr Maybe_CopyMove_Enabler& operator=(Maybe_CopyMove_Enabler&& aOther) {
+    downcast(aOther).reset();
+    return *this;
+  }
+
+ private:
+  MOZ_MAYBE_DOWNCAST()
+};
+
 template <typename T>
 class Maybe_CopyMove_Enabler<T, false, true, true> {
  public:
@@ -193,8 +222,9 @@ class Maybe_CopyMove_Enabler<T, false, true, false> {
   MOZ_MAYBE_DOWNCAST()
 };
 
-template <typename T>
-class Maybe_CopyMove_Enabler<T, false, false, false> {
+template <typename T, bool TriviallyDestructibleAndCopyable>
+class Maybe_CopyMove_Enabler<T, TriviallyDestructibleAndCopyable, false,
+                             false> {
  public:
   Maybe_CopyMove_Enabler() = default;
 
@@ -209,13 +239,12 @@ class Maybe_CopyMove_Enabler<T, false, false, false> {
 #undef MOZ_MAYBE_DOWNCAST
 
 template <typename T, bool TriviallyDestructibleAndCopyable =
-                          std::is_trivially_destructible_v<T>&&
-                              std::is_trivially_copy_constructible_v<T>>
+                          IsTriviallyDestructibleAndCopyable<T>>
 struct MaybeStorage;
 
 template <typename T>
 struct MaybeStorage<T, false> {
-  using NonConstT = typename RemoveConst<T>::Type;
+  using NonConstT = std::remove_const_t<T>;
 
   union Union {
     Union() {}
@@ -235,6 +264,11 @@ struct MaybeStorage<T, false> {
   explicit MaybeStorage(const T& aVal) : mStorage{aVal}, mIsSome{true} {}
   explicit MaybeStorage(T&& aVal) : mStorage{std::move(aVal)}, mIsSome{true} {}
 
+  template <typename... Args>
+  explicit MaybeStorage(std::in_place_t, Args&&... aArgs) : mIsSome{true} {
+    ::new (KnownNotNull, &mStorage.val) T(std::forward<Args>(aArgs)...);
+  }
+
   // Copy and move operations are no-ops, since copying is moving is implemented
   // by Maybe_CopyMove_Enabler.
 
@@ -252,23 +286,30 @@ struct MaybeStorage<T, false> {
 
 template <typename T>
 struct MaybeStorage<T, true> {
-  using NonConstT = typename RemoveConst<T>::Type;
+  using NonConstT = std::remove_const_t<T>;
 
   union Union {
     constexpr Union() : dummy() {}
     constexpr explicit Union(const T& aVal) : val{aVal} {}
     constexpr explicit Union(T&& aVal) : val{std::move(aVal)} {}
+    template <typename... Args>
+    constexpr explicit Union(std::in_place_t, Args&&... aArgs)
+        : val{std::forward<Args>(aArgs)...} {}
 
     NonConstT val;
     char dummy;
   } mStorage;
   char mIsSome = false;  // not bool -- guarantees minimal space consumption
 
-  MaybeStorage() = default;
+  constexpr MaybeStorage() = default;
   constexpr explicit MaybeStorage(const T& aVal)
       : mStorage{aVal}, mIsSome{true} {}
   constexpr explicit MaybeStorage(T&& aVal)
       : mStorage{std::move(aVal)}, mIsSome{true} {}
+
+  template <typename... Args>
+  constexpr explicit MaybeStorage(std::in_place_t, Args&&... aArgs)
+      : mStorage{std::in_place, std::forward<Args>(aArgs)...}, mIsSome{true} {}
 };
 
 }  // namespace detail
@@ -320,9 +361,6 @@ constexpr Maybe<U> Some(T&& aValue);
  * Boost. The most important differences between Maybe and std::optional are:
  *
  *   - std::optional<T> may be compared with T. We deliberately forbid that.
- *   - std::optional allows in-place construction without a separate call to
- *     |emplace()| by using a dummy |in_place_t| value to tag the appropriate
- *     constructor.
  *   - std::optional has |valueOr()|, equivalent to Maybe's |valueOr()|, but
  *     lacks corresponding methods for |refOr()| and |ptrOr()|.
  *   - std::optional lacks |map()| and |apply()|, making it less suitable for
@@ -359,6 +397,10 @@ class MOZ_INHERIT_TYPE_ANNOTATIONS_FROM_TEMPLATE_ARGS Maybe
 
   MOZ_ALLOW_TEMPORARY MOZ_IMPLICIT constexpr Maybe(Nothing) : Maybe{} {}
 
+  template <typename... Args>
+  constexpr explicit Maybe(std::in_place_t, Args&&... aArgs)
+      : detail::MaybeStorage<T>{std::in_place, std::forward<Args>(aArgs)...} {}
+
   /**
    * Maybe<T> can be copy-constructed from a Maybe<U> if T is constructible from
    * a const U&.
@@ -416,7 +458,7 @@ class MOZ_INHERIT_TYPE_ANNOTATIONS_FROM_TEMPLATE_ARGS Maybe
     return *this;
   }
 
-  Maybe& operator=(Nothing) {
+  constexpr Maybe& operator=(Nothing) {
     reset();
     return *this;
   }
@@ -430,6 +472,24 @@ class MOZ_INHERIT_TYPE_ANNOTATIONS_FROM_TEMPLATE_ARGS Maybe
    */
   constexpr T value() const;
 
+  /**
+   * Move the contents of this Maybe<T> out of internal storage and return it
+   * without calling the destructor. The internal storage is also reset to
+   * avoid multiple calls. Unsafe unless |isSome()|.
+   */
+  T extract() {
+    MOZ_DIAGNOSTIC_ASSERT(isSome());
+    auto v = std::move(mStorage.val);
+    reset();
+    return v;
+  }
+
+  /**
+   * Returns the value (possibly |Nothing()|) by moving it out of this Maybe<T>
+   * and leaving |Nothing()| in its place.
+   */
+  Maybe<T> take() { return std::exchange(*this, Nothing()); }
+
   /*
    * Returns the contents of this Maybe<T> by value. If |isNothing()|, returns
    * the default value provided.
@@ -457,7 +517,7 @@ class MOZ_INHERIT_TYPE_ANNOTATIONS_FROM_TEMPLATE_ARGS Maybe
   /* Returns the contents of this Maybe<T> by pointer. Unsafe unless |isSome()|.
    */
   T* ptr();
-  const T* ptr() const;
+  constexpr const T* ptr() const;
 
   /*
    * Returns the contents of this Maybe<T> by pointer. If |isNothing()|,
@@ -470,7 +530,7 @@ class MOZ_INHERIT_TYPE_ANNOTATIONS_FROM_TEMPLATE_ARGS Maybe
     return aDefault;
   }
 
-  const T* ptrOr(const T* aDefault) const {
+  constexpr const T* ptrOr(const T* aDefault) const {
     if (isSome()) {
       return ptr();
     }
@@ -683,6 +743,12 @@ class Maybe<T&> {
     return val;
   }
 
+  bool refEquals(const Maybe<T&>& aOther) const {
+    return mValue == aOther.mValue;
+  }
+
+  bool refEquals(const T& aOther) const { return mValue == &aOther; }
+
  private:
   T* mValue = nullptr;
 };
@@ -700,7 +766,7 @@ T* Maybe<T>::ptr() {
 }
 
 template <typename T>
-const T* Maybe<T>::ptr() const {
+constexpr const T* Maybe<T>::ptr() const {
   MOZ_DIAGNOSTIC_ASSERT(isSome());
   return &ref();
 }
@@ -772,8 +838,7 @@ constexpr Maybe<T&> SomeRef(T& aValue) {
 }
 
 template <typename T>
-Maybe<typename RemoveCV<typename RemoveReference<T>::Type>::Type> ToMaybe(
-    T* aPtr) {
+Maybe<std::remove_cv_t<std::remove_reference_t<T>>> ToMaybe(T* aPtr) {
   if (aPtr) {
     return Some(*aPtr);
   }
diff --git a/mfbt/MaybeOneOf.h b/mfbt/MaybeOneOf.h
index 299f94d805..cf812dfed4 100644
--- a/mfbt/MaybeOneOf.h
+++ b/mfbt/MaybeOneOf.h
@@ -10,14 +10,15 @@
 #ifndef mozilla_MaybeOneOf_h
 #define mozilla_MaybeOneOf_h
 
+#include <stddef.h>  // for size_t
+
+#include <new>  // for placement new
+#include <utility>
+
 #include "mozilla/Assertions.h"
-#include "mozilla/Move.h"
 #include "mozilla/OperatorNewExtensions.h"
 #include "mozilla/TemplateLib.h"
 
-#include <new>       // for placement new
-#include <stddef.h>  // for size_t
-
 namespace mozilla {
 
 /*
diff --git a/mfbt/Pair.h b/mfbt/Pair.h
deleted file mode 100644
index d0b9fe5f20..0000000000
--- a/mfbt/Pair.h
+++ /dev/null
@@ -1,188 +0,0 @@
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-/* A class holding a pair of objects that tries to conserve storage space. */
-
-#ifndef mozilla_Pair_h
-#define mozilla_Pair_h
-
-#include <type_traits>
-#include <utility>
-
-#include "mozilla/Attributes.h"
-#include "mozilla/TypeTraits.h"
-
-namespace mozilla {
-
-namespace detail {
-
-enum StorageType { AsBase, AsMember };
-
-// Optimize storage using the Empty Base Optimization -- that empty base classes
-// don't take up space -- to optimize size when one or the other class is
-// stateless and can be used as a base class.
-//
-// The extra conditions on storage for B are necessary so that PairHelper won't
-// ambiguously inherit from either A or B, such that one or the other base class
-// would be inaccessible.
-template <typename A, typename B,
-          detail::StorageType =
-              std::is_empty_v<A> ? detail::AsBase : detail::AsMember,
-          detail::StorageType = std::is_empty_v<B> &&
-                                        !std::is_base_of<A, B>::value &&
-                                        !std::is_base_of<B, A>::value
-                                    ? detail::AsBase
-                                    : detail::AsMember>
-struct PairHelper;
-
-template <typename A, typename B>
-struct PairHelper<A, B, AsMember, AsMember> {
- protected:
-  template <typename AArg, typename BArg>
-  PairHelper(AArg&& aA, BArg&& aB)
-      : mFirstA(std::forward<AArg>(aA)), mSecondB(std::forward<BArg>(aB)) {}
-
-  A& first() { return mFirstA; }
-  const A& first() const { return mFirstA; }
-  B& second() { return mSecondB; }
-  const B& second() const { return mSecondB; }
-
-  void swap(PairHelper& aOther) {
-    std::swap(mFirstA, aOther.mFirstA);
-    std::swap(mSecondB, aOther.mSecondB);
-  }
-
- private:
-  A mFirstA;
-  B mSecondB;
-};
-
-template <typename A, typename B>
-struct PairHelper<A, B, AsMember, AsBase> : private B {
- protected:
-  template <typename AArg, typename BArg>
-  PairHelper(AArg&& aA, BArg&& aB)
-      : B(std::forward<BArg>(aB)), mFirstA(std::forward<AArg>(aA)) {}
-
-  A& first() { return mFirstA; }
-  const A& first() const { return mFirstA; }
-  B& second() { return *this; }
-  const B& second() const { return *this; }
-
-  void swap(PairHelper& aOther) {
-    std::swap(mFirstA, aOther.mFirstA);
-    std::swap(static_cast<B&>(*this), static_cast<B&>(aOther));
-  }
-
- private:
-  A mFirstA;
-};
-
-template <typename A, typename B>
-struct PairHelper<A, B, AsBase, AsMember> : private A {
- protected:
-  template <typename AArg, typename BArg>
-  PairHelper(AArg&& aA, BArg&& aB)
-      : A(std::forward<AArg>(aA)), mSecondB(std::forward<BArg>(aB)) {}
-
-  A& first() { return *this; }
-  const A& first() const { return *this; }
-  B& second() { return mSecondB; }
-  const B& second() const { return mSecondB; }
-
-  void swap(PairHelper& aOther) {
-    std::swap(static_cast<A&>(*this), static_cast<A&>(aOther));
-    std::swap(mSecondB, aOther.mSecondB);
-  }
-
- private:
-  B mSecondB;
-};
-
-template <typename A, typename B>
-struct PairHelper<A, B, AsBase, AsBase> : private A, private B {
- protected:
-  template <typename AArg, typename BArg>
-  PairHelper(AArg&& aA, BArg&& aB)
-      : A(std::forward<AArg>(aA)), B(std::forward<BArg>(aB)) {}
-
-  A& first() { return static_cast<A&>(*this); }
-  const A& first() const { return static_cast<A&>(*this); }
-  B& second() { return static_cast<B&>(*this); }
-  const B& second() const { return static_cast<B&>(*this); }
-
-  void swap(PairHelper& aOther) {
-    std::swap(static_cast<A&>(*this), static_cast<A&>(aOther));
-    std::swap(static_cast<B&>(*this), static_cast<B&>(aOther));
-  }
-};
-
-}  // namespace detail
-
-/**
- * Pair is the logical concatenation of an instance of A with an instance B.
- * Space is conserved when possible.  Neither A nor B may be a final class.
- *
- * It's typically clearer to have individual A and B member fields.  Except if
- * you want the space-conserving qualities of Pair, you're probably better off
- * not using this!
- *
- * No guarantees are provided about the memory layout of A and B, the order of
- * initialization or destruction of A and B, and so on.  (This is approximately
- * required to optimize space usage.)  The first/second names are merely
- * conceptual!
- */
-template <typename A, typename B>
-struct Pair : private detail::PairHelper<A, B> {
-  typedef typename detail::PairHelper<A, B> Base;
-
- public:
-  template <typename AArg, typename BArg>
-  Pair(AArg&& aA, BArg&& aB)
-      : Base(std::forward<AArg>(aA), std::forward<BArg>(aB)) {}
-
-  Pair(Pair&& aOther) = default;
-  Pair(const Pair& aOther) = default;
-
-  Pair& operator=(Pair&& aOther) = default;
-  Pair& operator=(const Pair& aOther) = default;
-
-  /** The A instance. */
-  using Base::first;
-  /** The B instance. */
-  using Base::second;
-
-  /** Swap this pair with another pair. */
-  void swap(Pair& aOther) { Base::swap(aOther); }
-};
-
-/**
- * MakePair allows you to construct a Pair instance using type inference. A call
- * like this:
- *
- *   MakePair(Foo(), Bar())
- *
- * will return a Pair<Foo, Bar>.
- */
-template <typename A, typename B>
-Pair<typename RemoveCV<typename RemoveReference<A>::Type>::Type,
-     typename RemoveCV<typename RemoveReference<B>::Type>::Type>
-MakePair(A&& aA, B&& aB) {
-  return Pair<typename RemoveCV<typename RemoveReference<A>::Type>::Type,
-              typename RemoveCV<typename RemoveReference<B>::Type>::Type>(
-      std::forward<A>(aA), std::forward<B>(aB));
-}
-
-}  // namespace mozilla
-
-namespace std {
-
-template <typename A, class B>
-void swap(mozilla::Pair<A, B>& aX, mozilla::Pair<A, B>& aY) {
-  aX.swap(aY);
-}
-
-}  // namespace std
-
-#endif /* mozilla_Pair_h */
diff --git a/mfbt/RandomNum.cpp b/mfbt/RandomNum.cpp
index 61c0a14c64..862f8065c5 100644
--- a/mfbt/RandomNum.cpp
+++ b/mfbt/RandomNum.cpp
@@ -148,4 +148,12 @@ MFBT_API Maybe<uint64_t> RandomUint64() {
 #endif
 }
 
+MFBT_API uint64_t RandomUint64OrDie() {
+  Maybe<uint64_t> maybeRandomNum = RandomUint64();
+
+  MOZ_RELEASE_ASSERT(maybeRandomNum.isSome());
+
+  return maybeRandomNum.value();
+}
+
 }  // namespace mozilla
diff --git a/mfbt/RandomNum.h b/mfbt/RandomNum.h
index 94ed1b39a5..53a754aac0 100644
--- a/mfbt/RandomNum.h
+++ b/mfbt/RandomNum.h
@@ -28,6 +28,12 @@ namespace mozilla {
  */
 MFBT_API Maybe<uint64_t> RandomUint64();
 
+/**
+ *  Like RandomUint64, but always returns a uint64_t or crashes with an assert
+ *  if the underlying RandomUint64 call failed.
+ */
+MFBT_API uint64_t RandomUint64OrDie();
+
 }  // namespace mozilla
 
 #endif  // mozilla_RandomNum_h_
diff --git a/mfbt/Range.h b/mfbt/Range.h
index 3a51611411..c3877a74fd 100644
--- a/mfbt/Range.h
+++ b/mfbt/Range.h
@@ -10,6 +10,7 @@
 #include "mozilla/Span.h"
 
 #include <stddef.h>
+#include <type_traits>
 
 namespace mozilla {
 
@@ -32,15 +33,15 @@ class Range {
     MOZ_ASSERT(aStart <= aEnd);
   }
 
-  template <typename U, class = typename EnableIf<
-                            IsConvertible<U (*)[], T (*)[]>::value, int>::Type>
+  template <typename U, class = std::enable_if_t<
+                            std::is_convertible_v<U (*)[], T (*)[]>, int>>
   MOZ_IMPLICIT Range(const Range<U>& aOther)
       : mStart(aOther.mStart), mEnd(aOther.mEnd) {}
 
   MOZ_IMPLICIT Range(Span<T> aSpan) : Range(aSpan.Elements(), aSpan.Length()) {}
 
-  template <typename U, class = typename EnableIf<
-                            IsConvertible<U (*)[], T (*)[]>::value, int>::Type>
+  template <typename U, class = std::enable_if_t<
+                            std::is_convertible_v<U (*)[], T (*)[]>, int>>
   MOZ_IMPLICIT Range(const Span<U>& aSpan)
       : Range(aSpan.Elements(), aSpan.Length()) {}
 
diff --git a/mfbt/ReentrancyGuard.h b/mfbt/ReentrancyGuard.h
index 7305b9004b..7b5a17b888 100644
--- a/mfbt/ReentrancyGuard.h
+++ b/mfbt/ReentrancyGuard.h
@@ -9,13 +9,11 @@
 
 #include "mozilla/Assertions.h"
 #include "mozilla/Attributes.h"
-#include "mozilla/GuardObjects.h"
 
 namespace mozilla {
 
 /* Useful for implementing containers that assert non-reentrancy */
 class MOZ_RAII ReentrancyGuard {
-  MOZ_DECL_USE_GUARD_OBJECT_NOTIFIER
 #ifdef DEBUG
   bool& mEntered;
 #endif
@@ -23,13 +21,12 @@ class MOZ_RAII ReentrancyGuard {
  public:
   template <class T>
 #ifdef DEBUG
-  explicit ReentrancyGuard(T& aObj MOZ_GUARD_OBJECT_NOTIFIER_PARAM)
+  explicit ReentrancyGuard(T& aObj)
       : mEntered(aObj.mEntered)
 #else
-  explicit ReentrancyGuard(T& MOZ_GUARD_OBJECT_NOTIFIER_PARAM)
+  explicit ReentrancyGuard(T&)
 #endif
   {
-    MOZ_GUARD_OBJECT_NOTIFIER_INIT;
 #ifdef DEBUG
     MOZ_ASSERT(!mEntered);
     mEntered = true;
diff --git a/mfbt/RefCounted.h b/mfbt/RefCounted.h
index b1218efc16..2e35f0fd19 100644
--- a/mfbt/RefCounted.h
+++ b/mfbt/RefCounted.h
@@ -7,16 +7,16 @@
 #ifndef mozilla_RefCounted_h
 #define mozilla_RefCounted_h
 
+#include <atomic>
+#include <utility>
+
 #include "mozilla/AlreadyAddRefed.h"
 #include "mozilla/Assertions.h"
 #include "mozilla/Atomics.h"
 #include "mozilla/Attributes.h"
-#include "mozilla/Move.h"
 #include "mozilla/RefCountType.h"
 #include "mozilla/TypeTraits.h"
 
-#include <atomic>
-
 #if defined(MOZILLA_INTERNAL_API)
 #  include "nsXPCOM.h"
 #endif
diff --git a/mfbt/Result.h b/mfbt/Result.h
index 105785ddb1..9f881e2c64 100644
--- a/mfbt/Result.h
+++ b/mfbt/Result.h
@@ -11,8 +11,8 @@
 #include "mozilla/Alignment.h"
 #include "mozilla/Assertions.h"
 #include "mozilla/Attributes.h"
+#include "mozilla/CompactPair.h"
 #include "mozilla/Types.h"
-#include "mozilla/TypeTraits.h"
 #include "mozilla/Variant.h"
 
 namespace mozilla {
@@ -38,6 +38,9 @@ enum class PackingStrategy {
   PackedVariant,
 };
 
+template <typename T>
+struct UnusedZero;
+
 template <typename V, typename E, PackingStrategy Strategy>
 class ResultImplementation;
 
@@ -47,8 +50,8 @@ class ResultImplementation<V, E, PackingStrategy::Variant> {
 
  public:
   ResultImplementation(ResultImplementation&&) = default;
-  ResultImplementation(const ResultImplementation&) = default;
-  ResultImplementation& operator=(const ResultImplementation&) = default;
+  ResultImplementation(const ResultImplementation&) = delete;
+  ResultImplementation& operator=(const ResultImplementation&) = delete;
   ResultImplementation& operator=(ResultImplementation&&) = default;
 
   explicit ResultImplementation(V&& aValue)
@@ -70,82 +73,151 @@ class ResultImplementation<V, E, PackingStrategy::Variant> {
   const E& inspectErr() const { return mStorage.template as<E>(); }
 };
 
-/**
- * mozilla::Variant doesn't like storing a reference. This is a specialization
- * to store E as pointer if it's a reference.
- */
-template <typename V, typename E>
-class ResultImplementation<V, E&, PackingStrategy::Variant> {
-  mozilla::Variant<V, E*> mStorage;
-
- public:
-  explicit ResultImplementation(V&& aValue)
-      : mStorage(std::forward<V>(aValue)) {}
-  explicit ResultImplementation(const V& aValue) : mStorage(aValue) {}
-  explicit ResultImplementation(E& aErrorValue) : mStorage(&aErrorValue) {}
-
-  bool isOk() const { return mStorage.template is<V>(); }
-
-  const V& inspect() const { return mStorage.template as<V>(); }
-  V unwrap() { return std::move(mStorage.template as<V>()); }
-
-  E& unwrapErr() { return *mStorage.template as<E*>(); }
-  const E& inspectErr() const { return *mStorage.template as<E*>(); }
+// The purpose of EmptyWrapper is to make an empty class look like
+// AlignedStorage2 for the purposes of the PackingStrategy::NullIsOk
+// specializations of ResultImplementation below. We can't use AlignedStorage2
+// itself with an empty class, since it would no longer be empty, and we want to
+// avoid changing AlignedStorage2 just for this purpose.
+template <typename V>
+struct EmptyWrapper : V {
+  const V* addr() const { return this; }
+  V* addr() { return this; }
 };
 
-/**
- * Specialization for when the success type is Ok (or another empty class) and
- * the error type is a reference.
- */
+template <typename V>
+using AlignedStorageOrEmpty =
+    std::conditional_t<std::is_empty_v<V>, EmptyWrapper<V>, AlignedStorage2<V>>;
+
 template <typename V, typename E>
-class ResultImplementation<V, E&, PackingStrategy::NullIsOk> {
-  E* mErrorValue;
+class ResultImplementationNullIsOkBase {
+ protected:
+  using ErrorStorageType = typename UnusedZero<E>::StorageType;
 
- public:
-  explicit ResultImplementation(V) : mErrorValue(nullptr) {}
-  explicit ResultImplementation(E& aErrorValue) : mErrorValue(&aErrorValue) {}
+  static constexpr auto kNullValue = UnusedZero<E>::nullValue;
 
-  bool isOk() const { return mErrorValue == nullptr; }
-
-  const V& inspect() const = delete;
-  V unwrap() { return V(); }
-
-  const E& inspectErr() const { return *mErrorValue; }
-  E& unwrapErr() { return *mErrorValue; }
-};
-
-/**
- * Specialization for when the success type is Ok (or another empty class) and
- * the error type is a value type which can never have the value 0 (as
- * determined by UnusedZero<>).
- */
-template <typename V, typename E>
-class ResultImplementation<V, E, PackingStrategy::NullIsOk> {
-  static constexpr E NullValue = E(0);
-
-  E mErrorValue;
-
- public:
-  explicit ResultImplementation(V) : mErrorValue(NullValue) {}
-  explicit ResultImplementation(E aErrorValue) : mErrorValue(aErrorValue) {
-    MOZ_ASSERT(aErrorValue != NullValue);
+  // This is static function rather than a static data member in order to avoid
+  // that gcc emits lots of static constructors. It may be changed to a static
+  // constexpr data member with C++20.
+  static inline auto GetMovedFromMarker() {
+    return UnusedZero<E>::GetDefaultValue();
   }
 
-  bool isOk() const { return mErrorValue == NullValue; }
+  static_assert(std::is_trivially_copyable_v<ErrorStorageType>);
+  static_assert(kNullValue == decltype(kNullValue)(0));
 
-  const V& inspect() const = delete;
-  V unwrap() { return V(); }
+  CompactPair<AlignedStorageOrEmpty<V>, ErrorStorageType> mValue;
 
-  const E& inspectErr() const { return mErrorValue; }
-  E unwrapErr() { return std::move(mErrorValue); }
+ public:
+  explicit ResultImplementationNullIsOkBase(const V& aSuccessValue)
+      : mValue(std::piecewise_construct, std::tuple<>(),
+               std::tuple(kNullValue)) {
+    if constexpr (!std::is_empty_v<V>) {
+      new (mValue.first().addr()) V(aSuccessValue);
+    }
+  }
+  explicit ResultImplementationNullIsOkBase(V&& aSuccessValue)
+      : mValue(std::piecewise_construct, std::tuple<>(),
+               std::tuple(kNullValue)) {
+    if constexpr (!std::is_empty_v<V>) {
+      new (mValue.first().addr()) V(std::move(aSuccessValue));
+    }
+  }
+  explicit ResultImplementationNullIsOkBase(E aErrorValue)
+      : mValue(std::piecewise_construct, std::tuple<>(),
+               std::tuple(UnusedZero<E>::Store(std::move(aErrorValue)))) {
+    MOZ_ASSERT(mValue.second() != kNullValue);
+  }
+
+  ResultImplementationNullIsOkBase(ResultImplementationNullIsOkBase&& aOther)
+      : mValue(std::piecewise_construct, std::tuple<>(),
+               std::tuple(std::move(aOther.mValue.second()))) {
+    if constexpr (!std::is_empty_v<V>) {
+      if (isOk()) {
+        new (mValue.first().addr()) V(std::move(*aOther.mValue.first().addr()));
+        aOther.mValue.first().addr()->~V();
+        aOther.mValue.second() = GetMovedFromMarker();
+      }
+    }
+  }
+  ResultImplementationNullIsOkBase& operator=(
+      ResultImplementationNullIsOkBase&& aOther) {
+    if constexpr (!std::is_empty_v<V>) {
+      if (isOk()) {
+        mValue.first().addr()->~V();
+      }
+    }
+    mValue.second() = std::move(aOther.mValue.second());
+    if constexpr (!std::is_empty_v<V>) {
+      if (isOk()) {
+        new (mValue.first().addr()) V(std::move(*aOther.mValue.first().addr()));
+        aOther.mValue.first().addr()->~V();
+        aOther.mValue.second() = GetMovedFromMarker();
+      }
+    }
+    return *this;
+  }
+
+  bool isOk() const { return mValue.second() == kNullValue; }
+
+  const V& inspect() const { return *mValue.first().addr(); }
+  V unwrap() { return std::move(*mValue.first().addr()); }
+
+  const E& inspectErr() const {
+    return UnusedZero<E>::Inspect(mValue.second());
+  }
+  E unwrapErr() { return UnusedZero<E>::Unwrap(std::move(mValue.second())); }
+};
+
+template <typename V, typename E,
+          bool IsVTriviallyDestructible = std::is_trivially_destructible_v<V>>
+class ResultImplementationNullIsOk;
+
+template <typename V, typename E>
+class ResultImplementationNullIsOk<V, E, true>
+    : public ResultImplementationNullIsOkBase<V, E> {
+ public:
+  using ResultImplementationNullIsOkBase<V,
+                                         E>::ResultImplementationNullIsOkBase;
+};
+
+template <typename V, typename E>
+class ResultImplementationNullIsOk<V, E, false>
+    : public ResultImplementationNullIsOkBase<V, E> {
+ public:
+  using ResultImplementationNullIsOkBase<V,
+                                         E>::ResultImplementationNullIsOkBase;
+
+  ResultImplementationNullIsOk(ResultImplementationNullIsOk&&) = default;
+  ResultImplementationNullIsOk& operator=(ResultImplementationNullIsOk&&) =
+      default;
+
+  ~ResultImplementationNullIsOk() {
+    if (this->isOk()) {
+      this->mValue.first().addr()->~V();
+    }
+  }
 };
 
 /**
- * Specialization for when alignment permits using the least significant bit as
- * a tag bit.
+ * Specialization for when the success type is default-constructible and the
+ * error type is a value type which can never have the value 0 (as determined by
+ * UnusedZero<>).
  */
 template <typename V, typename E>
-class ResultImplementation<V*, E&, PackingStrategy::LowBitTagIsError> {
+class ResultImplementation<V, E, PackingStrategy::NullIsOk>
+    : public ResultImplementationNullIsOk<V, E> {
+ public:
+  using ResultImplementationNullIsOk<V, E>::ResultImplementationNullIsOk;
+};
+
+/**
+ * Specialization for when alignment permits using the least significant bit
+ * as a tag bit.
+ */
+template <typename V, typename E>
+class ResultImplementation<V*, E, PackingStrategy::LowBitTagIsError> {
+  static_assert(sizeof(E) <= sizeof(uintptr_t));
+
   uintptr_t mBits;
 
  public:
@@ -154,19 +226,16 @@ class ResultImplementation<V*, E&, PackingStrategy::LowBitTagIsError> {
     MOZ_ASSERT((uintptr_t(aValue) % MOZ_ALIGNOF(V)) == 0,
                "Result value pointers must not be misaligned");
   }
-  explicit ResultImplementation(E& aErrorValue)
-      : mBits(reinterpret_cast<uintptr_t>(&aErrorValue) | 1) {
-    MOZ_ASSERT((uintptr_t(&aErrorValue) % MOZ_ALIGNOF(E)) == 0,
-               "Result errors must not be misaligned");
-  }
+  explicit ResultImplementation(E aErrorValue)
+      : mBits(UnusedZero<E>::Store(aErrorValue) | 1) {}
 
   bool isOk() const { return (mBits & 1) == 0; }
 
   V* inspect() const { return reinterpret_cast<V*>(mBits); }
   V* unwrap() { return inspect(); }
 
-  E& inspectErr() const { return *reinterpret_cast<E*>(mBits ^ 1); }
-  E& unwrapErr() { return inspectErr(); }
+  auto inspectErr() const { return UnusedZero<E>::Inspect(mBits ^ 1); }
+  E unwrapErr() { return inspectErr(); }
 };
 
 // Return true if any of the struct can fit in a word.
@@ -183,8 +252,8 @@ struct IsPackableVariant {
     bool ok;
   };
 
-  using Impl = typename Conditional<sizeof(VEbool) <= sizeof(EVbool), VEbool,
-                                    EVbool>::Type;
+  using Impl =
+      std::conditional_t<sizeof(VEbool) <= sizeof(EVbool), VEbool, EVbool>;
 
   static const bool value = sizeof(Impl) <= sizeof(uintptr_t);
 };
@@ -226,12 +295,6 @@ struct UnusedZero {
   static const bool value = false;
 };
 
-// References can't be null.
-template <typename T>
-struct UnusedZero<T&> {
-  static const bool value = true;
-};
-
 // A bit of help figuring out which of the above specializations to use.
 //
 // We begin by safely assuming types don't have a spare bit.
@@ -254,36 +317,29 @@ struct HasFreeLSB<T*> {
   static const bool value = (alignof(T) & 1) == 0;
 };
 
-// We store references as pointers, so they have a free bit if a pointer would
-// have one.
-template <typename T>
-struct HasFreeLSB<T&> {
-  static const bool value = HasFreeLSB<T*>::value;
-};
-
 // Select one of the previous result implementation based on the properties of
 // the V and E types.
 template <typename V, typename E>
 struct SelectResultImpl {
   static const PackingStrategy value =
-      (std::is_empty_v<V> && UnusedZero<E>::value)
-          ? PackingStrategy::NullIsOk
-          : (detail::HasFreeLSB<V>::value && detail::HasFreeLSB<E>::value)
-                ? PackingStrategy::LowBitTagIsError
+      (HasFreeLSB<V>::value && HasFreeLSB<E>::value)
+          ? PackingStrategy::LowBitTagIsError
+          : (UnusedZero<E>::value && sizeof(E) <= sizeof(uintptr_t))
+                ? PackingStrategy::NullIsOk
                 : (std::is_default_constructible_v<V> &&
                    std::is_default_constructible_v<E> &&
                    IsPackableVariant<V, E>::value)
                       ? PackingStrategy::PackedVariant
                       : PackingStrategy::Variant;
 
-  using Type = detail::ResultImplementation<V, E, value>;
+  using Type = ResultImplementation<V, E, value>;
 };
 
 template <typename T>
-struct IsResult : FalseType {};
+struct IsResult : std::false_type {};
 
 template <typename V, typename E>
-struct IsResult<Result<V, E>> : TrueType {};
+struct IsResult<Result<V, E>> : std::true_type {};
 
 }  // namespace detail
 
@@ -302,30 +358,54 @@ auto ToResult(Result<V, E>&& aValue)
  * This is just like Variant<V, E> but with a slightly different API, and the
  * following cases are optimized so Result can be stored more efficiently:
  *
- * - If the success type is Ok (or another empty class) and the error type is a
- *   reference, Result<V, E&> is guaranteed to be pointer-sized and all zero
- *   bits on success. Do not change this representation! There is JIT code that
- *   depends on it.
+ * - If both the success and error types do not use their least significant bit,
+ * are trivially copyable and destructible, Result<V, E> is guaranteed to be as
+ * large as the larger type. This is determined via the HasFreeLSB trait. By
+ * default, empty classes (in particular Ok) and aligned pointer types are
+ * assumed to have a free LSB, but you can specialize this trait for other
+ * types. If the success type is empty, the representation is guaranteed to be
+ * all zero bits on success. Do not change this representation! There is JIT
+ * code that depends on it. (Implementation note: The lowest bit is used as a
+ * tag bit: 0 to indicate the Result's bits are a success value, 1 to indicate
+ * the Result's bits (with the 1 masked out) encode an error value)
  *
- * - If the success type is a pointer type and the error type is a reference
- *   type, and the least significant bit is unused for both types when stored
- *   as a pointer (due to alignment rules), Result<V*, E&> is guaranteed to be
- *   pointer-sized. In this case, we use the lowest bit as tag bit: 0 to
- *   indicate the Result's bits are a V, 1 to indicate the Result's bits (with
- *   the 1 masked out) encode an E*.
+ * - Else, if the error type can't have a all-zero bits representation and is
+ * not larger than a pointer, a CompactPair is used to represent this rather
+ * than a Variant. This has shown to be better optimizable, and the template
+ * code is much simpler than that of Variant, so it should also compile faster.
+ * Whether an error type can't be all-zero bits, is determined via the
+ * UnusedZero trait. MFBT doesn't declare any public type UnusedZero, but
+ * nsresult is declared UnusedZero in XPCOM.
  *
  * The purpose of Result is to reduce the screwups caused by using `false` or
  * `nullptr` to indicate errors.
  * What screwups? See <https://bugzilla.mozilla.org/show_bug.cgi?id=912928> for
  * a partial list.
+ *
+ * Result<const V, E> or Result<V, const E> are not meaningful. The success or
+ * error values in a Result instance are non-modifiable in-place anyway. This
+ * guarantee must also be maintained when evolving Result. They can be
+ * unwrap()ped, but this loses const qualification. However, Result<const V, E>
+ * or Result<V, const E> may be misleading and prevent movability. Just use
+ * Result<V, E>. (Result<const V*, E> may make sense though, just Result<const
+ * V* const, E> is not possible.)
  */
 template <typename V, typename E>
 class MOZ_MUST_USE_TYPE Result final {
+  // See class comment on Result<const V, E> and Result<V, const E>.
+  static_assert(!std::is_const_v<V>);
+  static_assert(!std::is_const_v<E>);
+  static_assert(!std::is_reference_v<V>);
+  static_assert(!std::is_reference_v<E>);
+
   using Impl = typename detail::SelectResultImpl<V, E>::Type;
 
   Impl mImpl;
 
  public:
+  using ok_type = V;
+  using err_type = E;
+
   /** Create a success result. */
   MOZ_IMPLICIT Result(V&& aValue) : mImpl(std::forward<V>(aValue)) {
     MOZ_ASSERT(isOk());
@@ -335,7 +415,7 @@ class MOZ_MUST_USE_TYPE Result final {
   MOZ_IMPLICIT Result(const V& aValue) : mImpl(aValue) { MOZ_ASSERT(isOk()); }
 
   /** Create an error result. */
-  explicit Result(E aErrorValue) : mImpl(std::forward<E>(aErrorValue)) {
+  explicit Result(E aErrorValue) : mImpl(std::move(aErrorValue)) {
     MOZ_ASSERT(isErr());
   }
 
@@ -345,9 +425,8 @@ class MOZ_MUST_USE_TYPE Result final {
    */
   template <typename E2>
   MOZ_IMPLICIT Result(GenericErrorResult<E2>&& aErrorResult)
-      : mImpl(std::forward<E2>(aErrorResult.mErrorValue)) {
-    static_assert(mozilla::IsConvertible<E2, E>::value,
-                  "E2 must be convertible to E");
+      : mImpl(std::move(aErrorResult.mErrorValue)) {
+    static_assert(std::is_convertible_v<E2, E>, "E2 must be convertible to E");
     MOZ_ASSERT(isErr());
   }
 
@@ -358,14 +437,13 @@ class MOZ_MUST_USE_TYPE Result final {
   template <typename E2>
   MOZ_IMPLICIT Result(const GenericErrorResult<E2>& aErrorResult)
       : mImpl(aErrorResult.mErrorValue) {
-    static_assert(mozilla::IsConvertible<E2, E>::value,
-                  "E2 must be convertible to E");
+    static_assert(std::is_convertible_v<E2, E>, "E2 must be convertible to E");
     MOZ_ASSERT(isErr());
   }
 
-  Result(const Result&) = default;
+  Result(const Result&) = delete;
   Result(Result&&) = default;
-  Result& operator=(const Result&) = default;
+  Result& operator=(const Result&) = delete;
   Result& operator=(Result&&) = default;
 
   /** True if this Result is a success result. */
@@ -404,9 +482,24 @@ class MOZ_MUST_USE_TYPE Result final {
     return mImpl.inspectErr();
   }
 
+  /** Propagate the error value from this Result, which must be an error result.
+   *
+   * This can be used to propagate an error from a function call to the caller
+   * with a different value type, but the same error type:
+   *
+   *    Result<T1, E> Func1() {
+   *       Result<T2, E> res = Func2();
+   *       if (res.isErr()) { return res.propagateErr(); }
+   *    }
+   */
+  GenericErrorResult<E> propagateErr() {
+    MOZ_ASSERT(isErr());
+    return GenericErrorResult<E>{mImpl.unwrapErr()};
+  }
+
   /**
-   * Map a function V -> W over this result's success variant. If this result is
-   * an error, do not invoke the function and return a copy of the error.
+   * Map a function V -> V2 over this result's success variant. If this result
+   * is an error, do not invoke the function and propagate the error.
    *
    * Mapping over success values invokes the function to produce a new success
    * value:
@@ -414,29 +507,32 @@ class MOZ_MUST_USE_TYPE Result final {
    *     // Map Result<int, E> to another Result<int, E>
    *     Result<int, E> res(5);
    *     Result<int, E> res2 = res.map([](int x) { return x * x; });
+   *     MOZ_ASSERT(res.isOk());
    *     MOZ_ASSERT(res2.unwrap() == 25);
    *
    *     // Map Result<const char*, E> to Result<size_t, E>
    *     Result<const char*, E> res("hello, map!");
    *     Result<size_t, E> res2 = res.map(strlen);
+   *     MOZ_ASSERT(res.isOk());
    *     MOZ_ASSERT(res2.unwrap() == 11);
    *
-   * Mapping over an error does not invoke the function and copies the error:
+   * Mapping over an error does not invoke the function and propagates the
+   * error:
    *
    *     Result<V, int> res(5);
    *     MOZ_ASSERT(res.isErr());
-   *     Result<W, int> res2 = res.map([](V v) { ... });
+   *     Result<V2, int> res2 = res.map([](V v) { ... });
    *     MOZ_ASSERT(res2.isErr());
    *     MOZ_ASSERT(res2.unwrapErr() == 5);
    */
   template <typename F>
-  auto map(F f) -> Result<decltype(f(*((V*)nullptr))), E> {
-    using RetResult = Result<decltype(f(*((V*)nullptr))), E>;
+  auto map(F f) -> Result<std::result_of_t<F(V)>, E> {
+    using RetResult = Result<std::result_of_t<F(V)>, E>;
     return MOZ_LIKELY(isOk()) ? RetResult(f(unwrap())) : RetResult(unwrapErr());
   }
 
   /**
-   * Map a function V -> W over this result's error variant. If this result is
+   * Map a function E -> E2 over this result's error variant. If this result is
    * a success, do not invoke the function and move the success over.
    *
    * Mapping over error values invokes the function to produce a new error
@@ -445,31 +541,94 @@ class MOZ_MUST_USE_TYPE Result final {
    *     // Map Result<V, int> to another Result<V, int>
    *     Result<V, int> res(5);
    *     Result<V, int> res2 = res.mapErr([](int x) { return x * x; });
+   *     MOZ_ASSERT(res2.isErr());
    *     MOZ_ASSERT(res2.unwrapErr() == 25);
    *
    *     // Map Result<V, const char*> to Result<V, size_t>
-   *     Result<V, const char*> res("hello, map!");
-   *     Result<size_t, E> res2 = res.mapErr(strlen);
-   *     MOZ_ASSERT(res2.unwrapErr() == 11);
+   *     Result<V, const char*> res("hello, mapErr!");
+   *     Result<V, size_t> res2 = res.mapErr(strlen);
+   *     MOZ_ASSERT(res2.isErr());
+   *     MOZ_ASSERT(res2.unwrapErr() == 14);
    *
-   * Mapping over a success does not invoke the function and copies the error:
+   * Mapping over a success does not invoke the function and moves the success:
    *
-   *     Result<int, V> res(5);
+   *     Result<int, E> res(5);
    *     MOZ_ASSERT(res.isOk());
-   *     Result<int, W> res2 = res.mapErr([](V v) { ... });
+   *     Result<int, E2> res2 = res.mapErr([](E e) { ... });
    *     MOZ_ASSERT(res2.isOk());
    *     MOZ_ASSERT(res2.unwrap() == 5);
    */
   template <typename F>
   auto mapErr(F f) -> Result<V, std::result_of_t<F(E)>> {
     using RetResult = Result<V, std::result_of_t<F(E)>>;
-    return isOk() ? RetResult(unwrap()) : RetResult(f(unwrapErr()));
+    return MOZ_UNLIKELY(isErr()) ? RetResult(f(unwrapErr()))
+                                 : RetResult(unwrap());
   }
 
   /**
-   * Given a function V -> Result<W, E>, apply it to this result's success value
-   * and return its result. If this result is an error value, then return a
-   * copy.
+   * Map a function E -> Result<V, E2> over this result's error variant. If
+   * this result is a success, do not invoke the function and move the success
+   * over.
+   *
+   * `orElse`ing over error values invokes the function to produce a new
+   * result:
+   *
+   *     // `orElse` Result<V, int> error variant to another Result<V, int>
+   *     // error variant or Result<V, int> success variant
+   *     auto orElse = [](int x) -> Result<V, int> {
+   *       if (x != 6) {
+   *         return Err(x * x);
+   *       }
+   *       return V(...);
+   *     };
+   *
+   *     Result<V, int> res(5);
+   *     auto res2 = res.orElse(orElse);
+   *     MOZ_ASSERT(res2.isErr());
+   *     MOZ_ASSERT(res2.unwrapErr() == 25);
+   *
+   *     Result<V, int> res3(6);
+   *     auto res4 = res3.orElse(orElse);
+   *     MOZ_ASSERT(res4.isOk());
+   *     MOZ_ASSERT(res4.unwrap() == ...);
+   *
+   *     // `orElse` Result<V, const char*> error variant to Result<V, size_t>
+   *     // error variant or Result<V, size_t> success variant
+   *     auto orElse = [](const char* s) -> Result<V, size_t> {
+   *       if (strcmp(s, "foo")) {
+   *         return Err(strlen(s));
+   *       }
+   *       return V(...);
+   *     };
+   *
+   *     Result<V, const char*> res("hello, orElse!");
+   *     auto res2 = res.orElse(orElse);
+   *     MOZ_ASSERT(res2.isErr());
+   *     MOZ_ASSERT(res2.unwrapErr() == 14);
+   *
+   *     Result<V, const char*> res3("foo");
+   *     auto res4 = ress.orElse(orElse);
+   *     MOZ_ASSERT(res4.isOk());
+   *     MOZ_ASSERT(res4.unwrap() == ...);
+   *
+   * `orElse`ing over a success does not invoke the function and moves the
+   * success:
+   *
+   *     Result<int, E> res(5);
+   *     MOZ_ASSERT(res.isOk());
+   *     Result<int, E2> res2 = res.orElse([](E e) { ... });
+   *     MOZ_ASSERT(res2.isOk());
+   *     MOZ_ASSERT(res2.unwrap() == 5);
+   */
+  template <typename F>
+  auto orElse(F f) -> Result<V, typename std::result_of_t<F(E)>::err_type> {
+    return MOZ_UNLIKELY(isErr()) ? f(unwrapErr()) : unwrap();
+  }
+
+  /**
+   * Given a function V -> Result<V2, E>, apply it to this result's success
+   * value and return its result. If this result is an error value, it is
+   * propagated.
    *
    * This is sometimes called "flatMap" or ">>=" in other contexts.
    *
@@ -487,18 +646,17 @@ class MOZ_MUST_USE_TYPE Result final {
    *     MOZ_ASSERT(res2.unwrap() == HtmlFreeString("hello, andThen!");
    *
    * `andThen`ing over error results does not invoke the function, and just
-   * produces a new copy of the error result:
+   * propagates the error result:
    *
    *     Result<int, const char*> res("some error");
    *     auto res2 = res.andThen([](int x) { ... });
    *     MOZ_ASSERT(res2.isErr());
    *     MOZ_ASSERT(res.unwrapErr() == res2.unwrapErr());
    */
-  template <typename F, typename = typename EnableIf<detail::IsResult<decltype(
-                            (*((F*)nullptr))(*((V*)nullptr)))>::value>::Type>
+  template <typename F, typename = std::enable_if_t<detail::IsResult<
+                            decltype((*((F*)nullptr))(*((V*)nullptr)))>::value>>
   auto andThen(F f) -> decltype(f(*((V*)nullptr))) {
-    return MOZ_LIKELY(isOk()) ? f(unwrap())
-                              : GenericErrorResult<E>(unwrapErr());
+    return MOZ_LIKELY(isOk()) ? f(unwrap()) : propagateErr();
   }
 };
 
@@ -516,13 +674,16 @@ class MOZ_MUST_USE_TYPE GenericErrorResult {
   friend class Result;
 
  public:
+  explicit GenericErrorResult(const E& aErrorValue)
+      : mErrorValue(aErrorValue) {}
+
   explicit GenericErrorResult(E&& aErrorValue)
-      : mErrorValue(std::forward<E>(aErrorValue)) {}
+      : mErrorValue(std::move(aErrorValue)) {}
 };
 
 template <typename E>
-inline GenericErrorResult<E> Err(E&& aErrorValue) {
-  return GenericErrorResult<E>(std::forward<E>(aErrorValue));
+inline auto Err(E&& aErrorValue) {
+  return GenericErrorResult<std::decay_t<E>>(std::forward<E>(aErrorValue));
 }
 
 }  // namespace mozilla
@@ -533,28 +694,27 @@ inline GenericErrorResult<E> Err(E&& aErrorValue) {
  * discards the result altogether. On error, it immediately returns an error
  * Result from the enclosing function.
  */
-#define MOZ_TRY(expr)                                       \
-  do {                                                      \
-    auto mozTryTempResult_ = ::mozilla::ToResult(expr);     \
-    if (MOZ_UNLIKELY(mozTryTempResult_.isErr())) {          \
-      return ::mozilla::Err(mozTryTempResult_.unwrapErr()); \
-    }                                                       \
+#define MOZ_TRY(expr)                                   \
+  do {                                                  \
+    auto mozTryTempResult_ = ::mozilla::ToResult(expr); \
+    if (MOZ_UNLIKELY(mozTryTempResult_.isErr())) {      \
+      return mozTryTempResult_.propagateErr();          \
+    }                                                   \
   } while (0)
 
 /**
  * MOZ_TRY_VAR(target, expr) is the C++ equivalent of Rust's `target =
  * try!(expr);`. First, it evaluates expr, which must produce a Result value. On
  * success, the result's success value is assigned to target. On error,
- * immediately returns the error result. |target| must evaluate to a reference
- * without any side effects.
+ * immediately returns the error result. |target| must be an lvalue.
  */
-#define MOZ_TRY_VAR(target, expr)                              \
-  do {                                                         \
-    auto mozTryVarTempResult_ = (expr);                        \
-    if (MOZ_UNLIKELY(mozTryVarTempResult_.isErr())) {          \
-      return ::mozilla::Err(mozTryVarTempResult_.unwrapErr()); \
-    }                                                          \
-    (target) = mozTryVarTempResult_.unwrap();                  \
+#define MOZ_TRY_VAR(target, expr)                     \
+  do {                                                \
+    auto mozTryVarTempResult_ = (expr);               \
+    if (MOZ_UNLIKELY(mozTryVarTempResult_.isErr())) { \
+      return mozTryVarTempResult_.propagateErr();     \
+    }                                                 \
+    (target) = mozTryVarTempResult_.unwrap();         \
   } while (0)
 
 #endif  // mozilla_Result_h
diff --git a/mfbt/ResultExtensions.h b/mfbt/ResultExtensions.h
index 352a342b6d..ae7b28bfa0 100644
--- a/mfbt/ResultExtensions.h
+++ b/mfbt/ResultExtensions.h
@@ -54,6 +54,279 @@ inline Result<Ok, nsresult> ToResult(PRStatus aValue) {
   return Err(NS_ERROR_FAILURE);
 }
 
+namespace detail {
+template <typename R>
+auto ResultRefAsParam(R& aResult) {
+  return &aResult;
+}
+
+template <typename R, typename RArgMapper, typename Func, typename... Args>
+Result<R, nsresult> ToResultInvokeInternal(const Func& aFunc,
+                                           const RArgMapper& aRArgMapper,
+                                           Args&&... aArgs) {
+  // XXX Thereotically, if R is a pointer to a non-refcounted type, this might
+  // be a non-owning pointer, but unless we find a case where this actually is
+  // relevant, it's safe to forbid any raw pointer result.
+  static_assert(
+      !std::is_pointer_v<R>,
+      "Raw pointer results are not supported, please specify a smart pointer "
+      "result type explicitly, so that getter_AddRefs is used");
+
+  R res;
+  nsresult rv = aFunc(std::forward<Args>(aArgs)..., aRArgMapper(res));
+  if (NS_FAILED(rv)) {
+    return Err(rv);
+  }
+  return res;
+}
+
+template <typename T>
+struct outparam_as_pointer;
+
+template <typename T>
+struct outparam_as_pointer<T*> {
+  using type = T*;
+};
+
+template <typename T>
+struct outparam_as_reference;
+
+template <typename T>
+struct outparam_as_reference<T*> {
+  using type = T&;
+};
+
+template <typename R, template <typename> typename RArg, typename Func,
+          typename... Args>
+using to_result_retval_t = decltype(
+    std::declval<Func&>()(std::declval<Args&&>()...,
+                          std::declval<typename RArg<decltype(
+                              ResultRefAsParam(std::declval<R&>()))>::type>()),
+    Result<R, nsresult>(Err(NS_ERROR_FAILURE)));
+
+// There are two ToResultInvokeSelector overloads, which cover the cases of a) a
+// pointer-typed output parameter, and b) a reference-typed output parameter,
+// using to_result_retval_t in connection with outparam_as_pointer and
+// outparam_as_reference type traits. These type traits may be specialized for
+// types other than raw pointers to allow calling functions with argument types
+// that implicitly convert/bind to a raw pointer/reference. The overload that is
+// used is selected by expression SFINAE: the decltype expression in
+// to_result_retval_t is only valid in either case.
+template <typename R, typename Func, typename... Args>
+auto ToResultInvokeSelector(const Func& aFunc, Args&&... aArgs)
+    -> to_result_retval_t<R, outparam_as_pointer, Func, Args...> {
+  return ToResultInvokeInternal<R>(
+      aFunc, [](R& res) -> decltype(auto) { return ResultRefAsParam(res); },
+      std::forward<Args>(aArgs)...);
+}
+
+template <typename R, typename Func, typename... Args>
+auto ToResultInvokeSelector(const Func& aFunc, Args&&... aArgs)
+    -> to_result_retval_t<R, outparam_as_reference, Func, Args...> {
+  return ToResultInvokeInternal<R>(
+      aFunc, [](R& res) -> decltype(auto) { return *ResultRefAsParam(res); },
+      std::forward<Args>(aArgs)...);
+}
+
+}  // namespace detail
+
+/**
+ * Adapts a function with a nsresult error type and an R* output parameter as
+ * the last parameter to a function returning a mozilla::Result<R, nsresult>
+ * object.
+ *
+ * This can also be used with member functions together with std::men_fn, e.g.
+ *
+ *    nsCOMPtr<nsIFile> file = ...;
+ *    auto existsOrErr = ToResultInvoke<bool>(std::mem_fn(&nsIFile::Exists),
+ *                                            *file);
+ *
+ * but it is more convenient to use the member function overload, which
+ * has the additional benefit of enabling the deduction of the success result
+ * type:
+ *
+ *    nsCOMPtr<nsIFile> file = ...;
+ *    auto existsOrErr = ToResultInvoke(*file, &nsIFile::Exists);
+ */
+template <typename R, typename Func, typename... Args>
+Result<R, nsresult> ToResultInvoke(const Func& aFunc, Args&&... aArgs) {
+  return detail::ToResultInvokeSelector<R, Func, Args&&...>(
+      aFunc, std::forward<Args>(aArgs)...);
+}
+
+namespace detail {
+template <typename T>
+struct tag {
+  using type = T;
+};
+
+template <typename... Ts>
+struct select_last {
+  using type = typename decltype((tag<Ts>{}, ...))::type;
+};
+
+template <typename... Ts>
+using select_last_t = typename select_last<Ts...>::type;
+
+template <>
+struct select_last<> {
+  using type = void;
+};
+
+template <typename RArg, typename T, typename Func, typename... Args>
+auto ToResultInvokeMemberFunction(T& aObj, const Func& aFunc, Args&&... aArgs) {
+  if constexpr (std::is_pointer_v<RArg> ||
+                (std::is_lvalue_reference_v<RArg> &&
+                 !std::is_const_v<std::remove_reference_t<RArg>>)) {
+    auto lambda = [&](RArg res) {
+      return (aObj.*aFunc)(std::forward<Args>(aArgs)..., res);
+    };
+    return detail::ToResultInvokeSelector<
+        std::remove_reference_t<std::remove_pointer_t<RArg>>, decltype(lambda)>(
+        lambda);
+  } else {
+    // No output parameter present, return a Result<Ok, nsresult>
+    return mozilla::ToResult((aObj.*aFunc)(std::forward<Args>(aArgs)...));
+  }
+}
+
+// For use in MOZ_TO_RESULT_INVOKE.
+template <typename T>
+auto DerefHelper(const T&) -> T&;
+
+template <typename T>
+auto DerefHelper(T*) -> T&;
+
+template <template <class> class SmartPtr, typename T,
+          typename = decltype(*std::declval<const SmartPtr<T>>())>
+auto DerefHelper(const SmartPtr<T>&) -> T&;
+
+template <typename T>
+using DerefedType =
+    std::remove_reference_t<decltype(DerefHelper(std::declval<const T&>()))>;
+}  // namespace detail
+
+template <typename T, typename U, typename... XArgs, typename... Args,
+          typename = std::enable_if_t<std::is_base_of_v<U, T>>>
+auto ToResultInvoke(T& aObj, nsresult (U::*aFunc)(XArgs...), Args&&... aArgs) {
+  return detail::ToResultInvokeMemberFunction<detail::select_last_t<XArgs...>>(
+      aObj, aFunc, std::forward<Args>(aArgs)...);
+}
+
+template <typename T, typename U, typename... XArgs, typename... Args,
+          typename = std::enable_if_t<std::is_base_of_v<U, T>>>
+auto ToResultInvoke(const T& aObj, nsresult (U::*aFunc)(XArgs...) const,
+                    Args&&... aArgs) {
+  return detail::ToResultInvokeMemberFunction<detail::select_last_t<XArgs...>>(
+      aObj, aFunc, std::forward<Args>(aArgs)...);
+}
+
+template <typename T, typename U, typename... XArgs, typename... Args>
+auto ToResultInvoke(T* const aObj, nsresult (U::*aFunc)(XArgs...),
+                    Args&&... aArgs) {
+  return ToResultInvoke(*aObj, aFunc, std::forward<Args>(aArgs)...);
+}
+
+template <typename T, typename U, typename... XArgs, typename... Args>
+auto ToResultInvoke(const T* const aObj, nsresult (U::*aFunc)(XArgs...) const,
+                    Args&&... aArgs) {
+  return ToResultInvoke(*aObj, aFunc, std::forward<Args>(aArgs)...);
+}
+
+template <template <class> class SmartPtr, typename T, typename U,
+          typename... XArgs, typename... Args,
+          typename = std::enable_if_t<std::is_base_of_v<U, T>>,
+          typename = decltype(*std::declval<const SmartPtr<T>>())>
+auto ToResultInvoke(const SmartPtr<T>& aObj, nsresult (U::*aFunc)(XArgs...),
+                    Args&&... aArgs) {
+  return ToResultInvoke(*aObj, aFunc, std::forward<Args>(aArgs)...);
+}
+
+template <template <class> class SmartPtr, typename T, typename U,
+          typename... XArgs, typename... Args,
+          typename = std::enable_if_t<std::is_base_of_v<U, T>>,
+          typename = decltype(*std::declval<const SmartPtr<T>>())>
+auto ToResultInvoke(const SmartPtr<const T>& aObj,
+                    nsresult (U::*aFunc)(XArgs...) const, Args&&... aArgs) {
+  return ToResultInvoke(*aObj, aFunc, std::forward<Args>(aArgs)...);
+}
+
+#if defined(XP_WIN) && !defined(_WIN64)
+template <typename T, typename U, typename... XArgs, typename... Args,
+          typename = std::enable_if_t<std::is_base_of_v<U, T>>>
+auto ToResultInvoke(T& aObj, nsresult (__stdcall U::*aFunc)(XArgs...),
+                    Args&&... aArgs) {
+  return detail::ToResultInvokeMemberFunction<detail::select_last_t<XArgs...>>(
+      aObj, aFunc, std::forward<Args>(aArgs)...);
+}
+
+template <typename T, typename U, typename... XArgs, typename... Args,
+          typename = std::enable_if_t<std::is_base_of_v<U, T>>>
+auto ToResultInvoke(const T& aObj,
+                    nsresult (__stdcall U::*aFunc)(XArgs...) const,
+                    Args&&... aArgs) {
+  return detail::ToResultInvokeMemberFunction<detail::select_last_t<XArgs...>>(
+      aObj, aFunc, std::forward<Args>(aArgs)...);
+}
+
+template <typename T, typename U, typename... XArgs, typename... Args>
+auto ToResultInvoke(T* const aObj, nsresult (__stdcall U::*aFunc)(XArgs...),
+                    Args&&... aArgs) {
+  return ToResultInvoke(*aObj, aFunc, std::forward<Args>(aArgs)...);
+}
+
+template <typename T, typename U, typename... XArgs, typename... Args>
+auto ToResultInvoke(const T* const aObj,
+                    nsresult (__stdcall U::*aFunc)(XArgs...) const,
+                    Args&&... aArgs) {
+  return ToResultInvoke(*aObj, aFunc, std::forward<Args>(aArgs)...);
+}
+
+template <template <class> class SmartPtr, typename T, typename U,
+          typename... XArgs, typename... Args,
+          typename = std::enable_if_t<std::is_base_of_v<U, T>>,
+          typename = decltype(*std::declval<const SmartPtr<T>>())>
+auto ToResultInvoke(const SmartPtr<T>& aObj,
+                    nsresult (__stdcall U::*aFunc)(XArgs...), Args&&... aArgs) {
+  return ToResultInvoke(*aObj, aFunc, std::forward<Args>(aArgs)...);
+}
+
+template <template <class> class SmartPtr, typename T, typename U,
+          typename... XArgs, typename... Args,
+          typename = std::enable_if_t<std::is_base_of_v<U, T>>,
+          typename = decltype(*std::declval<const SmartPtr<T>>())>
+auto ToResultInvoke(const SmartPtr<const T>& aObj,
+                    nsresult (__stdcall U::*aFunc)(XArgs...) const,
+                    Args&&... aArgs) {
+  return ToResultInvoke(*aObj, aFunc, std::forward<Args>(aArgs)...);
+}
+#endif
+
+// Macro version of ToResultInvoke for member functions. The macro has the
+// advantage of not requiring spelling out the member function's declarator type
+// name, at the expense of having a non-standard syntax. It can be used like
+// this:
+//
+//     nsCOMPtr<nsIFile> file;
+//     auto existsOrErr = MOZ_TO_RESULT_INVOKE(file, Exists);
+#define MOZ_TO_RESULT_INVOKE(obj, methodname, ...)                       \
+  ::mozilla::ToResultInvoke(                                             \
+      (obj), &::mozilla::detail::DerefedType<decltype(obj)>::methodname, \
+      ##__VA_ARGS__)
+
+// Macro version of ToResultInvoke for member functions, where the result type
+// does not match the output parameter type. The macro has the advantage of not
+// requiring spelling out the member function's declarator type name, at the
+// expense of having a non-standard syntax. It can be used like this:
+//
+//     nsCOMPtr<nsIFile> file;
+//     auto existsOrErr = MOZ_TO_RESULT_INVOKE(nsCOMPtr<nsIFile>, file, Clone);
+#define MOZ_TO_RESULT_INVOKE_TYPED(resultType, obj, methodname, ...)   \
+  ::mozilla::ToResultInvoke<resultType>(                               \
+      ::std::mem_fn(                                                   \
+          &::mozilla::detail::DerefedType<decltype(obj)>::methodname), \
+      (obj), ##__VA_ARGS__)
+
 }  // namespace mozilla
 
 #endif  // mozilla_ResultExtensions_h
diff --git a/mfbt/ReverseIterator.h b/mfbt/ReverseIterator.h
index c375b86393..207e18304f 100644
--- a/mfbt/ReverseIterator.h
+++ b/mfbt/ReverseIterator.h
@@ -12,25 +12,37 @@
 #include <utility>
 
 #include "mozilla/Attributes.h"
-#include "mozilla/TypeTraits.h"
 
 namespace mozilla {
 
+// This should only be used in cases where std::reverse_iterator cannot be used,
+// because the underlying iterator is not a proper bidirectional iterator, but
+// rather, e.g., a stashing iterator such as IntegerIterator. It is less
+// efficient than std::reverse_iterator for proper bidirectional iterators.
 template <typename IteratorT>
 class ReverseIterator {
  public:
-  template <typename Iterator>
-  explicit ReverseIterator(Iterator aIter) : mCurrent(aIter) {}
+  using value_type = typename IteratorT::value_type;
+  using pointer = typename IteratorT::pointer;
+  using reference = typename IteratorT::reference;
+  using difference_type = typename IteratorT::difference_type;
+  using iterator_category = typename IteratorT::iterator_category;
 
-  template <typename Iterator>
-  MOZ_IMPLICIT ReverseIterator(const ReverseIterator<Iterator>& aOther)
-      : mCurrent(aOther.mCurrent) {}
+  explicit ReverseIterator(IteratorT aIter) : mCurrent(std::move(aIter)) {}
 
+  // The return type is not reference, but rather the return type of
+  // Iterator::operator*(), which might be value_type, to allow this to work
+  // with stashing iterators such as IntegerIterator, see also Bug 1175485.
   decltype(*std::declval<IteratorT>()) operator*() const {
     IteratorT tmp = mCurrent;
     return *--tmp;
   }
 
+  /* Difference operator */
+  difference_type operator-(const ReverseIterator& aOther) const {
+    return aOther.mCurrent - mCurrent;
+  }
+
   /* Increments and decrements operators */
 
   ReverseIterator& operator++() {
@@ -115,21 +127,17 @@ bool operator>=(const ReverseIterator<Iterator1>& aIter1,
 
 namespace detail {
 
-template <typename IteratorT>
+template <typename IteratorT,
+          typename ReverseIteratorT = ReverseIterator<IteratorT>>
 class IteratorRange {
  public:
   typedef IteratorT iterator;
   typedef IteratorT const_iterator;
-  typedef ReverseIterator<IteratorT> reverse_iterator;
-  typedef ReverseIterator<IteratorT> const_reverse_iterator;
+  typedef ReverseIteratorT reverse_iterator;
+  typedef ReverseIteratorT const_reverse_iterator;
 
-  template <typename Iterator1, typename Iterator2>
-  MOZ_IMPLICIT IteratorRange(Iterator1 aIterBegin, Iterator2 aIterEnd)
-      : mIterBegin(aIterBegin), mIterEnd(aIterEnd) {}
-
-  template <typename Iterator>
-  MOZ_IMPLICIT IteratorRange(const IteratorRange<Iterator>& aOther)
-      : mIterBegin(aOther.mIterBegin), mIterEnd(aOther.mIterEnd) {}
+  IteratorRange(IteratorT aIterBegin, IteratorT aIterEnd)
+      : mIterBegin(std::move(aIterBegin)), mIterEnd(std::move(aIterEnd)) {}
 
   iterator begin() const { return mIterBegin; }
   const_iterator cbegin() const { return begin(); }
@@ -140,7 +148,6 @@ class IteratorRange {
   reverse_iterator rend() const { return reverse_iterator(mIterBegin); }
   const_reverse_iterator crend() const { return rend(); }
 
- private:
   IteratorT mIterBegin;
   IteratorT mIterEnd;
 };
diff --git a/mfbt/ScopeExit.h b/mfbt/ScopeExit.h
index 614ba3c59c..987b8ee31a 100644
--- a/mfbt/ScopeExit.h
+++ b/mfbt/ScopeExit.h
@@ -78,9 +78,9 @@
  *   scope.
  */
 
+#include <utility>
+
 #include "mozilla/Attributes.h"
-#include "mozilla/GuardObjects.h"
-#include "mozilla/Move.h"
 
 namespace mozilla {
 
@@ -88,13 +88,10 @@ template <typename ExitFunction>
 class MOZ_STACK_CLASS ScopeExit {
   ExitFunction mExitFunction;
   bool mExecuteOnDestruction;
-  MOZ_DECL_USE_GUARD_OBJECT_NOTIFIER
 
  public:
-  explicit ScopeExit(ExitFunction&& cleanup MOZ_GUARD_OBJECT_NOTIFIER_PARAM)
-      : mExitFunction(cleanup), mExecuteOnDestruction(true) {
-    MOZ_GUARD_OBJECT_NOTIFIER_INIT;
-  }
+  explicit ScopeExit(ExitFunction&& cleanup)
+      : mExitFunction(cleanup), mExecuteOnDestruction(true) {}
 
   ScopeExit(ScopeExit&& rhs)
       : mExitFunction(std::move(rhs.mExitFunction)),
diff --git a/mfbt/Scoped.h b/mfbt/Scoped.h
index 8c9827ca1c..20e5ae3eab 100644
--- a/mfbt/Scoped.h
+++ b/mfbt/Scoped.h
@@ -40,10 +40,10 @@
  *   and the resource is not deallocated by the class.
  */
 
+#include <utility>
+
 #include "mozilla/Assertions.h"
 #include "mozilla/Attributes.h"
-#include "mozilla/GuardObjects.h"
-#include "mozilla/Move.h"
 
 namespace mozilla {
 
@@ -67,20 +67,12 @@ class MOZ_NON_TEMPORARY_CLASS Scoped {
  public:
   typedef typename Traits::type Resource;
 
-  explicit Scoped(MOZ_GUARD_OBJECT_NOTIFIER_ONLY_PARAM)
-      : mValue(Traits::empty()) {
-    MOZ_GUARD_OBJECT_NOTIFIER_INIT;
-  }
+  explicit Scoped() : mValue(Traits::empty()) {}
 
-  explicit Scoped(const Resource& aValue MOZ_GUARD_OBJECT_NOTIFIER_PARAM)
-      : mValue(aValue) {
-    MOZ_GUARD_OBJECT_NOTIFIER_INIT;
-  }
+  explicit Scoped(const Resource& aValue) : mValue(aValue) {}
 
   /* Move constructor. */
-  Scoped(Scoped&& aOther MOZ_GUARD_OBJECT_NOTIFIER_PARAM)
-      : mValue(std::move(aOther.mValue)) {
-    MOZ_GUARD_OBJECT_NOTIFIER_INIT;
+  Scoped(Scoped&& aOther) : mValue(std::move(aOther.mValue)) {
     aOther.mValue = Traits::empty();
   }
 
@@ -150,7 +142,6 @@ class MOZ_NON_TEMPORARY_CLASS Scoped {
 
  private:
   Resource mValue;
-  MOZ_DECL_USE_GUARD_OBJECT_NOTIFIER
 };
 
 /*
@@ -161,28 +152,25 @@ class MOZ_NON_TEMPORARY_CLASS Scoped {
  * @param Traits A struct implementing clean-up. See the implementations
  * for more details.
  */
-#define SCOPED_TEMPLATE(name, Traits)                                         \
-  template <typename Type>                                                    \
-  struct MOZ_NON_TEMPORARY_CLASS name                                         \
-      : public mozilla::Scoped<Traits<Type> > {                               \
-    typedef mozilla::Scoped<Traits<Type> > Super;                             \
-    typedef typename Super::Resource Resource;                                \
-    name& operator=(Resource aRhs) {                                          \
-      Super::operator=(aRhs);                                                 \
-      return *this;                                                           \
-    }                                                                         \
-    name& operator=(name&& aRhs) = default;                                   \
-                                                                              \
-    explicit name(MOZ_GUARD_OBJECT_NOTIFIER_ONLY_PARAM)                       \
-        : Super(MOZ_GUARD_OBJECT_NOTIFIER_ONLY_PARAM_TO_PARENT) {}            \
-    explicit name(Resource aRhs MOZ_GUARD_OBJECT_NOTIFIER_PARAM)              \
-        : Super(aRhs MOZ_GUARD_OBJECT_NOTIFIER_PARAM_TO_PARENT) {}            \
-    name(name&& aRhs MOZ_GUARD_OBJECT_NOTIFIER_PARAM)                         \
-        : Super(std::move(aRhs) MOZ_GUARD_OBJECT_NOTIFIER_PARAM_TO_PARENT) {} \
-                                                                              \
-   private:                                                                   \
-    explicit name(const name&) = delete;                                      \
-    name& operator=(const name&) = delete;                                    \
+#define SCOPED_TEMPLATE(name, Traits)             \
+  template <typename Type>                        \
+  struct MOZ_NON_TEMPORARY_CLASS name             \
+      : public mozilla::Scoped<Traits<Type> > {   \
+    typedef mozilla::Scoped<Traits<Type> > Super; \
+    typedef typename Super::Resource Resource;    \
+    name& operator=(Resource aRhs) {              \
+      Super::operator=(aRhs);                     \
+      return *this;                               \
+    }                                             \
+    name& operator=(name&& aRhs) = default;       \
+                                                  \
+    explicit name() : Super() {}                  \
+    explicit name(Resource aRhs) : Super(aRhs) {} \
+    name(name&& aRhs) : Super(std::move(aRhs)) {} \
+                                                  \
+   private:                                       \
+    explicit name(const name&) = delete;          \
+    name& operator=(const name&) = delete;        \
   };
 
 /*
diff --git a/mfbt/SegmentedVector.h b/mfbt/SegmentedVector.h
index dbfff93371..606bd3bab9 100644
--- a/mfbt/SegmentedVector.h
+++ b/mfbt/SegmentedVector.h
@@ -18,17 +18,17 @@
 #ifndef mozilla_SegmentedVector_h
 #define mozilla_SegmentedVector_h
 
+#include <new>  // for placement new
+#include <utility>
+
 #include "mozilla/AllocPolicy.h"
 #include "mozilla/Array.h"
 #include "mozilla/Attributes.h"
 #include "mozilla/LinkedList.h"
 #include "mozilla/MemoryReporting.h"
-#include "mozilla/Move.h"
 #include "mozilla/OperatorNewExtensions.h"
 #include "mozilla/TypeTraits.h"
 
-#include <new>  // for placement new
-
 namespace mozilla {
 
 // |IdealSegmentSize| specifies how big each segment will be in bytes (or as
diff --git a/mfbt/Span.h b/mfbt/Span.h
index ff14b133c4..22efe7b38f 100644
--- a/mfbt/Span.h
+++ b/mfbt/Span.h
@@ -70,16 +70,6 @@ inline size_t strlen16(const char16_t* aZeroTerminated) {
   return len;
 }
 
-// C++14 types that we don't have because we build as C++11.
-template <class T>
-using remove_cv_t = typename mozilla::RemoveCV<T>::Type;
-template <class T>
-using remove_const_t = typename mozilla::RemoveConst<T>::Type;
-template <bool B, class T, class F>
-using conditional_t = typename mozilla::Conditional<B, T, F>::Type;
-template <bool B, class T = void>
-using enable_if_t = typename mozilla::EnableIf<B, T>::Type;
-
 template <class T>
 struct is_span_oracle : mozilla::FalseType {};
 
@@ -88,7 +78,7 @@ struct is_span_oracle<mozilla::Span<ElementType, Extent>> : mozilla::TrueType {
 };
 
 template <class T>
-struct is_span : public is_span_oracle<remove_cv_t<T>> {};
+struct is_span : public is_span_oracle<std::remove_cv_t<T>> {};
 
 template <class T>
 struct is_std_array_oracle : mozilla::FalseType {};
@@ -98,45 +88,63 @@ struct is_std_array_oracle<std::array<ElementType, Extent>>
     : mozilla::TrueType {};
 
 template <class T>
-struct is_std_array : public is_std_array_oracle<remove_cv_t<T>> {};
+struct is_std_array : public is_std_array_oracle<std::remove_cv_t<T>> {};
 
 template <size_t From, size_t To>
 struct is_allowed_extent_conversion
-    : public mozilla::IntegralConstant<
-          bool, From == To || From == mozilla::dynamic_extent ||
-                    To == mozilla::dynamic_extent> {};
+    : public std::integral_constant<bool, From == To ||
+                                              From == mozilla::dynamic_extent ||
+                                              To == mozilla::dynamic_extent> {};
 
 template <class From, class To>
 struct is_allowed_element_type_conversion
-    : public mozilla::IntegralConstant<
-          bool, mozilla::IsConvertible<From (*)[], To (*)[]>::value> {};
+    : public std::integral_constant<
+          bool, std::is_convertible_v<From (*)[], To (*)[]>> {};
 
-template <class Span, bool IsConst>
+struct SpanKnownBounds {};
+
+template <class SpanT, bool IsConst>
 class span_iterator {
-  using element_type_ = typename Span::element_type;
+  using element_type_ = typename SpanT::element_type;
+
+  template <class ElementType, size_t Extent> friend class ::mozilla::Span;
 
  public:
   using iterator_category = std::random_access_iterator_tag;
-  using value_type = remove_const_t<element_type_>;
-  using difference_type = typename Span::index_type;
+  using value_type = std::remove_const_t<element_type_>;
+  using difference_type = typename SpanT::index_type;
 
-  using reference = conditional_t<IsConst, const element_type_, element_type_>&;
+  using reference =
+      std::conditional_t<IsConst, const element_type_, element_type_>&;
   using pointer = std::add_pointer_t<reference>;
 
-  constexpr span_iterator() : span_iterator(nullptr, 0) {}
+  constexpr span_iterator() : span_iterator(nullptr, 0, SpanKnownBounds{}) {}
 
-  constexpr span_iterator(const Span* span, typename Span::index_type index)
+  constexpr span_iterator(const SpanT* span, typename SpanT::index_type index)
       : span_(span), index_(index) {
     MOZ_RELEASE_ASSERT(span == nullptr ||
                        (index_ >= 0 && index <= span_->Length()));
   }
 
-  friend class span_iterator<Span, true>;
-  constexpr MOZ_IMPLICIT span_iterator(const span_iterator<Span, false>& other)
-      : span_iterator(other.span_, other.index_) {}
+ private:
+  // For whatever reason, the compiler doesn't like optimizing away the above
+  // MOZ_RELEASE_ASSERT when `span_iterator` is constructed for obviously-correct
+  // cases like `span.begin()` or `span.end()`.  We provide this private
+  // constructor for such cases.
+  constexpr span_iterator(const SpanT* span, typename SpanT::index_type index,
+			  SpanKnownBounds)
+      : span_(span), index_(index) {}
 
-  constexpr span_iterator<Span, IsConst>& operator=(
-      const span_iterator<Span, IsConst>&) = default;
+ public:
+  // `other` is already correct by construction; we do not need to go through
+  // the release assert above.  Put differently, this constructor is effectively
+  // a copy constructor and therefore needs no assertions.
+  friend class span_iterator<SpanT, true>;
+  constexpr MOZ_IMPLICIT span_iterator(const span_iterator<SpanT, false>& other)
+      : span_(other.span_), index_(other.index_) {}
+
+  constexpr span_iterator<SpanT, IsConst>& operator=(
+      const span_iterator<SpanT, IsConst>&) = default;
 
   constexpr reference operator*() const {
     MOZ_RELEASE_ASSERT(span_);
@@ -149,7 +157,6 @@ class span_iterator {
   }
 
   constexpr span_iterator& operator++() {
-    MOZ_RELEASE_ASSERT(span_ && index_ >= 0 && index_ < span_->Length());
     ++index_;
     return *this;
   }
@@ -161,7 +168,6 @@ class span_iterator {
   }
 
   constexpr span_iterator& operator--() {
-    MOZ_RELEASE_ASSERT(span_ && index_ > 0 && index_ <= span_->Length());
     --index_;
     return *this;
   }
@@ -237,7 +243,7 @@ class span_iterator {
   }
 
  protected:
-  const Span* span_;
+  const SpanT* span_;
   size_t index_;
 };
 
@@ -373,17 +379,17 @@ class Span {
   constexpr static const index_type extent = Extent;
 
   // [Span.cons], Span constructors, copy, assignment, and destructor
-  // "Dependent" is needed to make "span_details::enable_if_t<(Dependent ||
+  // "Dependent" is needed to make "std::enable_if_t<(Dependent ||
   //   Extent == 0 || Extent == dynamic_extent)>" SFINAE,
   // since
-  // "span_details::enable_if_t<(Extent == 0 || Extent == dynamic_extent)>" is
+  // "std::enable_if_t<(Extent == 0 || Extent == dynamic_extent)>" is
   // ill-formed when Extent is neither of the extreme values.
   /**
    * Constructor with no args.
    */
   template <bool Dependent = false,
-            class = span_details::enable_if_t<(Dependent || Extent == 0 ||
-                                               Extent == dynamic_extent)>>
+            class = std::enable_if_t<(Dependent || Extent == 0 ||
+                                      Extent == dynamic_extent)>>
   constexpr Span() : storage_(nullptr, span_details::extent_type<0>()) {}
 
   /**
@@ -434,7 +440,7 @@ class Span {
    * Constructor for std::array.
    */
   template <size_t N,
-            class ArrayElementType = span_details::remove_const_t<element_type>>
+            class ArrayElementType = std::remove_const_t<element_type>>
   constexpr MOZ_IMPLICIT Span(std::array<ArrayElementType, N>& aArr)
       : storage_(&aArr[0], span_details::extent_type<N>()) {}
 
@@ -443,14 +449,14 @@ class Span {
    */
   template <size_t N>
   constexpr MOZ_IMPLICIT Span(
-      const std::array<span_details::remove_const_t<element_type>, N>& aArr)
+      const std::array<std::remove_const_t<element_type>, N>& aArr)
       : storage_(&aArr[0], span_details::extent_type<N>()) {}
 
   /**
    * Constructor for mozilla::Array.
    */
   template <size_t N,
-            class ArrayElementType = span_details::remove_const_t<element_type>>
+            class ArrayElementType = std::remove_const_t<element_type>>
   constexpr MOZ_IMPLICIT Span(mozilla::Array<ArrayElementType, N>& aArr)
       : storage_(&aArr[0], span_details::extent_type<N>()) {}
 
@@ -459,7 +465,7 @@ class Span {
    */
   template <size_t N>
   constexpr MOZ_IMPLICIT Span(
-      const mozilla::Array<span_details::remove_const_t<element_type>, N>& aArr)
+      const mozilla::Array<std::remove_const_t<element_type>, N>& aArr)
       : storage_(&aArr[0], span_details::extent_type<N>()) {}
 
   /**
@@ -477,13 +483,12 @@ class Span {
    */
   template <
       class Container,
-      class = span_details::enable_if_t<
+      class = std::enable_if_t<
           !span_details::is_span<Container>::value &&
           !span_details::is_std_array<Container>::value &&
-          mozilla::IsConvertible<typename Container::pointer, pointer>::value &&
-          mozilla::IsConvertible<
-              typename Container::pointer,
-              decltype(mozilla::DeclVal<Container>().data())>::value>>
+          std::is_convertible_v<typename Container::pointer, pointer> &&
+          std::is_convertible_v<typename Container::pointer,
+                                decltype(std::declval<Container>().data())>>>
   constexpr MOZ_IMPLICIT Span(Container& cont)
       : Span(cont.data(), ReleaseAssertedCast<index_type>(cont.size())) {}
 
@@ -492,13 +497,12 @@ class Span {
    */
   template <
       class Container,
-      class = span_details::enable_if_t<
+      class = std::enable_if_t<
           std::is_const_v<element_type> &&
           !span_details::is_span<Container>::value &&
-          mozilla::IsConvertible<typename Container::pointer, pointer>::value &&
-          mozilla::IsConvertible<
-              typename Container::pointer,
-              decltype(mozilla::DeclVal<Container>().data())>::value>>
+          std::is_convertible_v<typename Container::pointer, pointer> &&
+          std::is_convertible_v<typename Container::pointer,
+                                decltype(std::declval<Container>().data())>>>
   constexpr MOZ_IMPLICIT Span(const Container& cont)
       : Span(cont.data(), ReleaseAssertedCast<index_type>(cont.size())) {}
 
@@ -515,12 +519,12 @@ class Span {
   /**
    * Constructor from other Span with conversion of element type.
    */
-  template <class OtherElementType, size_t OtherExtent,
-            class = span_details::enable_if_t<
-                span_details::is_allowed_extent_conversion<OtherExtent,
-                                                           Extent>::value &&
-                span_details::is_allowed_element_type_conversion<
-                    OtherElementType, element_type>::value>>
+  template <
+      class OtherElementType, size_t OtherExtent,
+      class = std::enable_if_t<span_details::is_allowed_extent_conversion<
+                                   OtherExtent, Extent>::value &&
+                               span_details::is_allowed_element_type_conversion<
+                                   OtherElementType, element_type>::value>>
   constexpr MOZ_IMPLICIT Span(const Span<OtherElementType, OtherExtent>& other)
       : storage_(other.data(),
                  span_details::extent_type<OtherExtent>(other.size())) {}
@@ -528,12 +532,12 @@ class Span {
   /**
    * Constructor from other Span with conversion of element type.
    */
-  template <class OtherElementType, size_t OtherExtent,
-            class = span_details::enable_if_t<
-                span_details::is_allowed_extent_conversion<OtherExtent,
-                                                           Extent>::value &&
-                span_details::is_allowed_element_type_conversion<
-                    OtherElementType, element_type>::value>>
+  template <
+      class OtherElementType, size_t OtherExtent,
+      class = std::enable_if_t<span_details::is_allowed_extent_conversion<
+                                   OtherExtent, Extent>::value &&
+                               span_details::is_allowed_element_type_conversion<
+                                   OtherElementType, element_type>::value>>
   constexpr MOZ_IMPLICIT Span(Span<OtherElementType, OtherExtent>&& other)
       : storage_(other.data(),
                  span_details::extent_type<OtherExtent>(other.size())) {}
@@ -691,11 +695,11 @@ class Span {
   constexpr pointer data() const { return storage_.data(); }
 
   // [Span.iter], Span iterator support
-  iterator begin() const { return {this, 0}; }
-  iterator end() const { return {this, Length()}; }
+  iterator begin() const { return {this, 0, span_details::SpanKnownBounds{}}; }
+  iterator end() const { return {this, Length(), span_details::SpanKnownBounds{}}; }
 
-  const_iterator cbegin() const { return {this, 0}; }
-  const_iterator cend() const { return {this, Length()}; }
+  const_iterator cbegin() const { return {this, 0, span_details::SpanKnownBounds{}}; }
+  const_iterator cend() const { return {this, Length(), span_details::SpanKnownBounds{}}; }
 
   reverse_iterator rbegin() const { return reverse_iterator{end()}; }
   reverse_iterator rend() const { return reverse_iterator{begin()}; }
@@ -723,6 +727,10 @@ class Span {
     return {First(aSplitPoint), Last(Length() - aSplitPoint)};
   }
 
+  constexpr Span<std::add_const_t<ElementType>, Extent> AsConst() const {
+    return {Elements(), Length()};
+  }
+
  private:
   // this implementation detail class lets us take advantage of the
   // empty base class optimization to pay for only storage of a single
@@ -814,13 +822,14 @@ namespace span_details {
 // see it as constexpr and so will fail compilation of the template
 template <class ElementType, size_t Extent>
 struct calculate_byte_size
-    : mozilla::IntegralConstant<size_t, static_cast<size_t>(
-                                            sizeof(ElementType) *
-                                            static_cast<size_t>(Extent))> {};
+    : std::integral_constant<size_t,
+                             static_cast<size_t>(sizeof(ElementType) *
+                                                 static_cast<size_t>(Extent))> {
+};
 
 template <class ElementType>
 struct calculate_byte_size<ElementType, dynamic_extent>
-    : mozilla::IntegralConstant<size_t, dynamic_extent> {};
+    : std::integral_constant<size_t, dynamic_extent> {};
 }  // namespace span_details
 
 // [Span.objectrep], views of object representation
@@ -838,7 +847,7 @@ AsBytes(Span<ElementType, Extent> s) {
  * View span as Span<uint8_t>.
  */
 template <class ElementType, size_t Extent,
-          class = span_details::enable_if_t<!std::is_const_v<ElementType>>>
+          class = std::enable_if_t<!std::is_const_v<ElementType>>>
 Span<uint8_t, span_details::calculate_byte_size<ElementType, Extent>::value>
 AsWritableBytes(Span<ElementType, Extent> s) {
   return {reinterpret_cast<uint8_t*>(s.data()), s.size_bytes()};
@@ -888,9 +897,8 @@ Span<ElementType> MakeSpan(ElementType* aStartPtr, ElementType* aEndPtr) {
  * string literal's full length.
  */
 template <class ElementType, size_t N,
-          class = span_details::enable_if_t<
-              !IsSame<ElementType, const char>::value &&
-              !IsSame<ElementType, const char16_t>::value>>
+          class = std::enable_if_t<!IsSame<ElementType, const char>::value &&
+                                   !IsSame<ElementType, const char16_t>::value>>
 Span<ElementType> MakeSpan(ElementType (&aArr)[N]) {
   return Span<ElementType>(aArr, N);
 }
diff --git a/mfbt/TemplateLib.h b/mfbt/TemplateLib.h
index f9f31361f5..4fa869ac11 100644
--- a/mfbt/TemplateLib.h
+++ b/mfbt/TemplateLib.h
@@ -17,8 +17,7 @@
 
 #include <limits.h>
 #include <stddef.h>
-
-#include "mozilla/TypeTraits.h"
+#include <type_traits>
 
 namespace mozilla {
 
@@ -127,14 +126,8 @@ struct MulOverflowMask<1> {
  *   mozilla::t1::And<>::value is true.
  */
 
-template <bool...>
-struct And;
-
-template <>
-struct And<> : public TrueType {};
-
-template <bool C1, bool... Cn>
-struct And<C1, Cn...> : public Conditional<C1, And<Cn...>, FalseType>::Type {};
+template <bool... C>
+struct And : std::integral_constant<bool, (C && ...)> {};
 
 }  // namespace tl
 
diff --git a/mfbt/Tuple.h b/mfbt/Tuple.h
index 10e1781ee2..12fd43c912 100644
--- a/mfbt/Tuple.h
+++ b/mfbt/Tuple.h
@@ -12,9 +12,8 @@
 #include <type_traits>
 #include <utility>
 
-#include "mozilla/Pair.h"
+#include "mozilla/CompactPair.h"
 #include "mozilla/TemplateLib.h"
-#include "mozilla/TypeTraits.h"
 
 namespace mozilla {
 
@@ -47,14 +46,15 @@ template <typename Source, typename Target, bool SameSize>
 struct CheckConvertibilityImpl;
 
 template <typename Source, typename Target>
-struct CheckConvertibilityImpl<Source, Target, false> : FalseType {};
+struct CheckConvertibilityImpl<Source, Target, false> : std::false_type {};
 
 template <typename... SourceTypes, typename... TargetTypes>
 struct CheckConvertibilityImpl<Group<SourceTypes...>, Group<TargetTypes...>,
                                true>
-    : IntegralConstant<
+    : std::integral_constant<
           bool,
-          tl::And<IsConvertible<SourceTypes, TargetTypes>::value...>::value> {};
+          tl::And<std::is_convertible_v<SourceTypes, TargetTypes>...>::value> {
+};
 
 template <typename Source, typename Target>
 struct CheckConvertibility;
@@ -65,6 +65,19 @@ struct CheckConvertibility<Group<SourceTypes...>, Group<TargetTypes...>>
                               sizeof...(SourceTypes) ==
                                   sizeof...(TargetTypes)> {};
 
+/*
+ * Helper type for Tie(args...) to allow ignoring specific elements
+ * during Tie unpacking.  Supports assignment from any type.
+ *
+ * Not for direct usage; instead, use mozilla::Ignore in calls to Tie.
+ */
+struct IgnoreImpl {
+  template <typename T>
+  constexpr const IgnoreImpl& operator=(const T&) const {
+    return *this;
+  }
+};
+
 /*
  * TupleImpl is a helper class used to implement mozilla::Tuple.
  * It represents one node in a recursive inheritance hierarchy.
@@ -134,10 +147,10 @@ struct TupleImpl<Index, HeadT, TailT...>
   // This constructor is enabled only when the argument types are actually
   // convertible to the element types, otherwise it could become a better
   // match for certain invocations than the copy constructor.
-  template <typename OtherHeadT, typename... OtherTailT,
-            typename = typename EnableIf<
-                CheckConvertibility<Group<OtherHeadT, OtherTailT...>,
-                                    Group<HeadT, TailT...>>::value>::Type>
+  template <
+      typename OtherHeadT, typename... OtherTailT,
+      typename = std::enable_if_t<CheckConvertibility<
+          Group<OtherHeadT, OtherTailT...>, Group<HeadT, TailT...>>::value>>
   explicit TupleImpl(OtherHeadT&& aHead, OtherTailT&&... aTail)
       : Base(std::forward<OtherTailT>(aTail)...),
         mHead(std::forward<OtherHeadT>(aHead)) {}
@@ -154,8 +167,8 @@ struct TupleImpl<Index, HeadT, TailT...>
   // Assign from a tuple whose elements are convertible to the elements
   // of this tuple.
   template <typename... OtherElements,
-            typename = typename EnableIf<sizeof...(OtherElements) ==
-                                         sizeof...(TailT) + 1>::Type>
+            typename = std::enable_if_t<sizeof...(OtherElements) ==
+                                        sizeof...(TailT) + 1>>
   TupleImpl& operator=(const TupleImpl<Index, OtherElements...>& aOther) {
     typedef TupleImpl<Index, OtherElements...> OtherT;
     Head(*this) = OtherT::Head(aOther);
@@ -163,8 +176,8 @@ struct TupleImpl<Index, HeadT, TailT...>
     return *this;
   }
   template <typename... OtherElements,
-            typename = typename EnableIf<sizeof...(OtherElements) ==
-                                         sizeof...(TailT) + 1>::Type>
+            typename = std::enable_if_t<sizeof...(OtherElements) ==
+                                        sizeof...(TailT) + 1>>
   TupleImpl& operator=(TupleImpl<Index, OtherElements...>&& aOther) {
     typedef TupleImpl<Index, OtherElements...> OtherT;
     Head(*this) = std::move(OtherT::Head(aOther));
@@ -213,8 +226,8 @@ struct TupleImpl<Index, HeadT, TailT...>
 
 /**
  * Tuple is a class that stores zero or more objects, whose types are specified
- * as template parameters. It can be thought of as a generalization of Pair,
- * (which can be thought of as a 2-tuple).
+ * as template parameters. It can be thought of as a generalization of
+ * std::pair, (which can be thought of as a 2-tuple).
  *
  * Tuple allows index-based access to its elements (with the index having to be
  * known at compile time) via the non-member function 'Get<N>(tuple)'.
@@ -234,9 +247,9 @@ class Tuple : public detail::TupleImpl<0, Elements...> {
   // actually instantiates the constructor with an empty parameter pack -
   // that's probably a bug) and we compile with warnings-as-errors.
   template <typename OtherHead, typename... OtherTail,
-            typename = typename EnableIf<detail::CheckConvertibility<
+            typename = std::enable_if_t<detail::CheckConvertibility<
                 detail::Group<OtherHead, OtherTail...>,
-                detail::Group<Elements...>>::value>::Type>
+                detail::Group<Elements...>>::value>>
   explicit Tuple(OtherHead&& aHead, OtherTail&&... aTail)
       : Impl(std::forward<OtherHead>(aHead),
              std::forward<OtherTail>(aTail)...) {}
@@ -244,15 +257,15 @@ class Tuple : public detail::TupleImpl<0, Elements...> {
   Tuple(Tuple&& aOther) : Impl(std::move(aOther)) {}
 
   template <typename... OtherElements,
-            typename = typename EnableIf<sizeof...(OtherElements) ==
-                                         sizeof...(Elements)>::Type>
+            typename = std::enable_if_t<sizeof...(OtherElements) ==
+                                        sizeof...(Elements)>>
   Tuple& operator=(const Tuple<OtherElements...>& aOther) {
     static_cast<Impl&>(*this) = aOther;
     return *this;
   }
   template <typename... OtherElements,
-            typename = typename EnableIf<sizeof...(OtherElements) ==
-                                         sizeof...(Elements)>::Type>
+            typename = std::enable_if_t<sizeof...(OtherElements) ==
+                                        sizeof...(Elements)>>
   Tuple& operator=(Tuple<OtherElements...>&& aOther) {
     static_cast<Impl&>(*this) = std::move(aOther);
     return *this;
@@ -272,7 +285,7 @@ class Tuple : public detail::TupleImpl<0, Elements...> {
 
 /**
  * Specialization of Tuple for two elements.
- * This is created to support construction and assignment from a Pair or
+ * This is created to support construction and assignment from a CompactPair or
  * std::pair.
  */
 template <typename A, typename B>
@@ -286,15 +299,15 @@ class Tuple<A, B> : public detail::TupleImpl<0, A, B> {
   Tuple() : Impl() {}
   explicit Tuple(const A& aA, const B& aB) : Impl(aA, aB) {}
   template <typename AArg, typename BArg,
-            typename = typename EnableIf<detail::CheckConvertibility<
-                detail::Group<AArg, BArg>, detail::Group<A, B>>::value>::Type>
+            typename = std::enable_if_t<detail::CheckConvertibility<
+                detail::Group<AArg, BArg>, detail::Group<A, B>>::value>>
   explicit Tuple(AArg&& aA, BArg&& aB)
       : Impl(std::forward<AArg>(aA), std::forward<BArg>(aB)) {}
   Tuple(const Tuple& aOther) : Impl(aOther) {}
   Tuple(Tuple&& aOther) : Impl(std::move(aOther)) {}
-  explicit Tuple(const Pair<A, B>& aOther)
+  explicit Tuple(const CompactPair<A, B>& aOther)
       : Impl(aOther.first(), aOther.second()) {}
-  explicit Tuple(Pair<A, B>&& aOther)
+  explicit Tuple(CompactPair<A, B>&& aOther)
       : Impl(std::forward<A>(aOther.first()),
              std::forward<B>(aOther.second())) {}
   explicit Tuple(const std::pair<A, B>& aOther)
@@ -321,13 +334,13 @@ class Tuple<A, B> : public detail::TupleImpl<0, A, B> {
     return *this;
   }
   template <typename AArg, typename BArg>
-  Tuple& operator=(const Pair<AArg, BArg>& aOther) {
+  Tuple& operator=(const CompactPair<AArg, BArg>& aOther) {
     Impl::Head(*this) = aOther.first();
     Impl::Tail(*this).Head(*this) = aOther.second();
     return *this;
   }
   template <typename AArg, typename BArg>
-  Tuple& operator=(Pair<AArg, BArg>&& aOther) {
+  Tuple& operator=(CompactPair<AArg, BArg>&& aOther) {
     Impl::Head(*this) = std::forward<AArg>(aOther.first());
     Impl::Tail(*this).Head(*this) = std::forward<BArg>(aOther.second());
     return *this;
@@ -461,6 +474,22 @@ inline Tuple<std::decay_t<Elements>...> MakeTuple(Elements&&... aElements) {
   return Tuple<std::decay_t<Elements>...>(std::forward<Elements>(aElements)...);
 }
 
+/**
+ * A helper placholder to allow ignoring specific elements during Tie unpacking.
+ * Can be used with any type and any number of elements in a call to Tie.
+ *
+ * Usage of Ignore with Tie is equivalent to using std::ignore with
+ * std::tie.
+ *
+ * Example:
+ *
+ * int i;
+ * float f;
+ * char c;
+ * Tie(i, Ignore, f, c, Ignore) = FunctionThatReturnsATuple();
+ */
+constexpr detail::IgnoreImpl Ignore;
+
 /**
  * A convenience function for constructing a tuple of references to a
  * sequence of variables. Since assignments to the elements of the tuple
diff --git a/mfbt/TypeTraits.h b/mfbt/TypeTraits.h
index 7dc9af5fad..25245a558e 100644
--- a/mfbt/TypeTraits.h
+++ b/mfbt/TypeTraits.h
@@ -9,6 +9,8 @@
 
 #include "mozilla/Types.h"
 
+#include <utility>
+
 /*
  * These traits are approximate copies of the traits and semantics from C++11's
  * <type_traits> header.  Don't add traits not in that header!  When all
@@ -21,19 +23,6 @@ namespace mozilla {
 
 template <typename>
 struct RemoveCV;
-template <typename>
-struct AddRvalueReference;
-
-/* 20.2.4 Function template declval [declval] */
-
-/**
- * DeclVal simplifies the definition of expressions which occur as unevaluated
- * operands. It converts T to a reference type, making it possible to use in
- * decltype expressions even if T does not have a default constructor, e.g.:
- * decltype(DeclVal<TWithNoDefaultConstructor>().foo())
- */
-template <typename T>
-typename AddRvalueReference<T>::Type DeclVal();
 
 /* 20.9.3 Helper classes [meta.help] */
 
@@ -77,30 +66,6 @@ struct IsVoidHelper<void> : TrueType {};
 template <typename T>
 struct IsVoid : detail::IsVoidHelper<typename RemoveCV<T>::Type> {};
 
-namespace detail {
-
-template <typename T>
-struct IsArrayHelper : FalseType {};
-
-template <typename T, decltype(sizeof(1)) N>
-struct IsArrayHelper<T[N]> : TrueType {};
-
-template <typename T>
-struct IsArrayHelper<T[]> : TrueType {};
-
-}  // namespace detail
-
-/**
- * IsArray determines whether a type is an array type, of known or unknown
- * length.
- *
- * mozilla::IsArray<int>::value is false;
- * mozilla::IsArray<int[]>::value is true;
- * mozilla::IsArray<int[5]>::value is true.
- */
-template <typename T>
-struct IsArray : detail::IsArrayHelper<typename RemoveCV<T>::Type> {};
-
 /* 20.9.4.3 Type properties [meta.unary.prop] */
 
 /**
@@ -152,7 +117,7 @@ struct IsPod<T*> : TrueType {};
 namespace detail {
 
 struct DoIsDestructibleImpl {
-  template <typename T, typename = decltype(DeclVal<T&>().~T())>
+  template <typename T, typename = decltype(std::declval<T&>().~T())>
   static TrueType test(int);
   template <typename T>
   static FalseType test(...);
@@ -199,64 +164,6 @@ struct IsSame : FalseType {};
 template <typename T>
 struct IsSame<T, T> : TrueType {};
 
-namespace detail {
-
-template <typename From, typename To>
-struct ConvertibleTester {
- private:
-  template <typename To1>
-  static char test_helper(To1);
-
-  template <typename From1, typename To1>
-  static decltype(test_helper<To1>(DeclVal<From1>())) test(int);
-
-  template <typename From1, typename To1>
-  static int test(...);
-
- public:
-  static const bool value = sizeof(test<From, To>(0)) == sizeof(char);
-};
-
-}  // namespace detail
-
-/**
- * IsConvertible determines whether a value of type From will implicitly convert
- * to a value of type To.  For example:
- *
- *   struct A {};
- *   struct B : public A {};
- *   struct C {};
- *
- * mozilla::IsConvertible<A, A>::value is true;
- * mozilla::IsConvertible<A*, A*>::value is true;
- * mozilla::IsConvertible<B, A>::value is true;
- * mozilla::IsConvertible<B*, A*>::value is true;
- * mozilla::IsConvertible<C, A>::value is false;
- * mozilla::IsConvertible<A, C>::value is false;
- * mozilla::IsConvertible<A*, C*>::value is false;
- * mozilla::IsConvertible<C*, A*>::value is false.
- *
- * For obscure reasons, you can't use IsConvertible when the types being tested
- * are related through private inheritance, and you'll get a compile error if
- * you try.  Just don't do it!
- *
- * Note - we need special handling for void, which ConvertibleTester doesn't
- * handle. The void handling here doesn't handle const/volatile void correctly,
- * which could be easily fixed if the need arises.
- */
-template <typename From, typename To>
-struct IsConvertible
-    : IntegralConstant<bool, detail::ConvertibleTester<From, To>::value> {};
-
-template <typename B>
-struct IsConvertible<void, B> : IntegralConstant<bool, IsVoid<B>::value> {};
-
-template <typename A>
-struct IsConvertible<A, void> : IntegralConstant<bool, IsVoid<A>::value> {};
-
-template <>
-struct IsConvertible<void, void> : TrueType {};
-
 /* 20.9.7 Transformations between types [meta.trans] */
 
 /* 20.9.7.1 Const-volatile modifications [meta.trans.cv] */
@@ -312,29 +219,6 @@ struct RemoveCV {
 
 /* 20.9.7.2 Reference modifications [meta.trans.ref] */
 
-/**
- * Converts reference types to the underlying types.
- *
- * mozilla::RemoveReference<T>::Type is T;
- * mozilla::RemoveReference<T&>::Type is T;
- * mozilla::RemoveReference<T&&>::Type is T;
- */
-
-template <typename T>
-struct RemoveReference {
-  typedef T Type;
-};
-
-template <typename T>
-struct RemoveReference<T&> {
-  typedef T Type;
-};
-
-template <typename T>
-struct RemoveReference<T&&> {
-  typedef T Type;
-};
-
 namespace detail {
 
 enum Voidness { TIsVoid, TIsNotVoid };
@@ -372,85 +256,6 @@ struct AddRvalueReferenceHelper<T, TIsNotVoid> {
 template <typename T>
 struct AddRvalueReference : detail::AddRvalueReferenceHelper<T> {};
 
-/* 20.9.7.5 Pointer modifications [meta.trans.ptr] */
-
-namespace detail {
-
-template <typename T, typename CVRemoved>
-struct RemovePointerHelper {
-  typedef T Type;
-};
-
-template <typename T, typename Pointee>
-struct RemovePointerHelper<T, Pointee*> {
-  typedef Pointee Type;
-};
-
-}  // namespace detail
-
-/**
- * Produces the pointed-to type if a pointer is provided, else returns the input
- * type.  Note that this does not dereference pointer-to-member pointers.
- *
- * struct S { bool m; void f(); };
- * mozilla::RemovePointer<int>::Type is int;
- * mozilla::RemovePointer<int*>::Type is int;
- * mozilla::RemovePointer<int* const>::Type is int;
- * mozilla::RemovePointer<int* volatile>::Type is int;
- * mozilla::RemovePointer<const long*>::Type is const long;
- * mozilla::RemovePointer<void* const>::Type is void;
- * mozilla::RemovePointer<void (S::*)()>::Type is void (S::*)();
- * mozilla::RemovePointer<void (*)()>::Type is void();
- * mozilla::RemovePointer<bool S::*>::Type is bool S::*.
- */
-template <typename T>
-struct RemovePointer
-    : detail::RemovePointerHelper<T, typename RemoveCV<T>::Type> {};
-
-/* 20.9.7.6 Other transformations [meta.trans.other] */
-
-/**
- * EnableIf is a struct containing a typedef of T if and only if B is true.
- *
- * mozilla::EnableIf<true, int>::Type is int;
- * mozilla::EnableIf<false, int>::Type is a compile-time error.
- *
- * Use this template to implement SFINAE-style (Substitution Failure Is not An
- * Error) requirements.  For example, you might use it to impose a restriction
- * on a template parameter:
- *
- *   template<typename T>
- *   class PodVector // vector optimized to store POD (memcpy-able) types
- *   {
- *      EnableIf<IsPod<T>::value, T>::Type* vector;
- *      size_t length;
- *      ...
- *   };
- */
-template <bool B, typename T = void>
-struct EnableIf {};
-
-template <typename T>
-struct EnableIf<true, T> {
-  typedef T Type;
-};
-
-/**
- * Conditional selects a class between two, depending on a given boolean value.
- *
- * mozilla::Conditional<true, A, B>::Type is A;
- * mozilla::Conditional<false, A, B>::Type is B;
- */
-template <bool Condition, typename A, typename B>
-struct Conditional {
-  typedef A Type;
-};
-
-template <class A, class B>
-struct Conditional<false, A, B> {
-  typedef B Type;
-};
-
 } /* namespace mozilla */
 
 #endif /* mozilla_TypeTraits_h */
diff --git a/mfbt/UniquePtr.h b/mfbt/UniquePtr.h
index d3f6ff64cb..d1a03ec0a4 100644
--- a/mfbt/UniquePtr.h
+++ b/mfbt/UniquePtr.h
@@ -12,9 +12,8 @@
 
 #include "mozilla/Assertions.h"
 #include "mozilla/Attributes.h"
+#include "mozilla/CompactPair.h"
 #include "mozilla/Compiler.h"
-#include "mozilla/Pair.h"
-#include "mozilla/TypeTraits.h"
 
 namespace mozilla {
 
@@ -38,8 +37,8 @@ struct HasPointerTypeHelper {
 
 template <class T>
 class HasPointerType
-    : public IntegralConstant<bool,
-                              sizeof(HasPointerTypeHelper::Test<T>(0)) == 1> {};
+    : public std::integral_constant<bool, sizeof(HasPointerTypeHelper::Test<T>(
+                                              0)) == 1> {};
 
 template <class T, class D, bool = HasPointerType<D>::value>
 struct PointerTypeImpl {
@@ -53,8 +52,7 @@ struct PointerTypeImpl<T, D, false> {
 
 template <class T, class D>
 struct PointerType {
-  typedef
-      typename PointerTypeImpl<T, typename RemoveReference<D>::Type>::Type Type;
+  typedef typename PointerTypeImpl<T, std::remove_reference_t<D>>::Type Type;
 };
 
 }  // namespace detail
@@ -193,7 +191,7 @@ class UniquePtr {
   typedef typename detail::PointerType<T, DeleterType>::Type Pointer;
 
  private:
-  Pair<Pointer, DeleterType> mTuple;
+  mozilla::CompactPair<Pointer, DeleterType> mTuple;
 
   Pointer& ptr() { return mTuple.first(); }
   const Pointer& ptr() const { return mTuple.first(); }
@@ -219,32 +217,10 @@ class UniquePtr {
   }
 
   UniquePtr(Pointer aPtr,
-            typename Conditional<std::is_reference_v<D>, D, const D&>::Type aD1)
+            std::conditional_t<std::is_reference_v<D>, D, const D&> aD1)
       : mTuple(aPtr, aD1) {}
 
-  // If you encounter an error with MSVC10 about RemoveReference below, along
-  // the lines that "more than one partial specialization matches the template
-  // argument list": don't use UniquePtr<T, reference to function>!  Ideally
-  // you should make deletion use the same function every time, using a
-  // deleter policy:
-  //
-  //   // BAD, won't compile with MSVC10, deleter doesn't need to be a
-  //   // variable at all
-  //   typedef void (&FreeSignature)(void*);
-  //   UniquePtr<int, FreeSignature> ptr((int*) malloc(sizeof(int)), free);
-  //
-  //   // GOOD, compiles with MSVC10, deletion behavior statically known and
-  //   // optimizable
-  //   struct DeleteByFreeing
-  //   {
-  //     void operator()(void* aPtr) { free(aPtr); }
-  //   };
-  //
-  // If deletion really, truly, must be a variable: you might be able to work
-  // around this with a deleter class that contains the function reference.
-  // But this workaround is untried and untested, because variable deletion
-  // behavior really isn't something you should use.
-  UniquePtr(Pointer aPtr, typename RemoveReference<D>::Type&& aD2)
+  UniquePtr(Pointer aPtr, std::remove_reference_t<D>&& aD2)
       : mTuple(aPtr, std::move(aD2)) {
     static_assert(!std::is_reference_v<D>,
                   "rvalue deleter can't be stored by reference");
@@ -263,12 +239,13 @@ class UniquePtr {
   template <typename U, class E>
   MOZ_IMPLICIT UniquePtr(
       UniquePtr<U, E>&& aOther,
-      typename EnableIf<
-          IsConvertible<typename UniquePtr<U, E>::Pointer, Pointer>::value &&
-              !IsArray<U>::value &&
-              (std::is_reference_v<D> ? IsSame<D, E>::value
-                                      : IsConvertible<E, D>::value),
-          int>::Type aDummy = 0)
+      std::enable_if_t<
+          std::is_convertible_v<typename UniquePtr<U, E>::Pointer, Pointer> &&
+              !std::is_array_v<U> &&
+              (std::is_reference_v<D> ? std::is_same_v<D, E>
+                                      : std::is_convertible_v<E, D>),
+          int>
+          aDummy = 0)
       : mTuple(aOther.release(), std::forward<E>(aOther.get_deleter())) {}
 
   ~UniquePtr() { reset(nullptr); }
@@ -282,9 +259,9 @@ class UniquePtr {
   template <typename U, typename E>
   UniquePtr& operator=(UniquePtr<U, E>&& aOther) {
     static_assert(
-        IsConvertible<typename UniquePtr<U, E>::Pointer, Pointer>::value,
+        std::is_convertible_v<typename UniquePtr<U, E>::Pointer, Pointer>,
         "incompatible UniquePtr pointees");
-    static_assert(!IsArray<U>::value,
+    static_assert(!std::is_array_v<U>,
                   "can't assign from UniquePtr holding an array");
 
     reset(aOther.release());
@@ -343,7 +320,7 @@ class UniquePtr<T[], D> {
   typedef D DeleterType;
 
  private:
-  Pair<Pointer, DeleterType> mTuple;
+  mozilla::CompactPair<Pointer, DeleterType> mTuple;
 
  public:
   /**
@@ -368,19 +345,16 @@ class UniquePtr<T[], D> {
   // So forbid all overloads which would end up invoking delete[] on a pointer
   // of the wrong type.
   template <typename U>
-  UniquePtr(U&& aU, typename EnableIf<std::is_pointer_v<U> &&
-                                          IsConvertible<U, Pointer>::value,
-                                      int>::Type aDummy = 0) = delete;
+  UniquePtr(U&& aU,
+            std::enable_if_t<
+                std::is_pointer_v<U> && std::is_convertible_v<U, Pointer>, int>
+                aDummy = 0) = delete;
 
   UniquePtr(Pointer aPtr,
-            typename Conditional<std::is_reference_v<D>, D, const D&>::Type aD1)
+            std::conditional_t<std::is_reference_v<D>, D, const D&> aD1)
       : mTuple(aPtr, aD1) {}
 
-  // If you encounter an error with MSVC10 about RemoveReference below, along
-  // the lines that "more than one partial specialization matches the template
-  // argument list": don't use UniquePtr<T[], reference to function>!  See the
-  // comment by this constructor in the non-T[] specialization above.
-  UniquePtr(Pointer aPtr, typename RemoveReference<D>::Type&& aD2)
+  UniquePtr(Pointer aPtr, std::remove_reference_t<D>&& aD2)
       : mTuple(aPtr, std::move(aD2)) {
     static_assert(!std::is_reference_v<D>,
                   "rvalue deleter can't be stored by reference");
@@ -389,9 +363,9 @@ class UniquePtr<T[], D> {
   // Forbidden for the same reasons as stated above.
   template <typename U, typename V>
   UniquePtr(U&& aU, V&& aV,
-            typename EnableIf<std::is_pointer_v<U> &&
-                                  IsConvertible<U, Pointer>::value,
-                              int>::Type aDummy = 0) = delete;
+            std::enable_if_t<
+                std::is_pointer_v<U> && std::is_convertible_v<U, Pointer>, int>
+                aDummy = 0) = delete;
 
   UniquePtr(UniquePtr&& aOther)
       : mTuple(aOther.release(),
@@ -477,8 +451,7 @@ class DefaultDelete {
   template <typename U>
   MOZ_IMPLICIT DefaultDelete(
       const DefaultDelete<U>& aOther,
-      typename EnableIf<mozilla::IsConvertible<U*, T*>::value, int>::Type
-          aDummy = 0) {}
+      std::enable_if_t<std::is_convertible_v<U*, T*>, int> aDummy = 0) {}
 
   void operator()(T* aPtr) const {
     static_assert(sizeof(T) > 0, "T must be complete");
@@ -511,6 +484,26 @@ bool operator!=(const UniquePtr<T, D>& aX, const UniquePtr<U, E>& aY) {
   return aX.get() != aY.get();
 }
 
+template <typename T, class D>
+bool operator==(const UniquePtr<T, D>& aX, const T* aY) {
+  return aX.get() == aY;
+}
+
+template <typename T, class D>
+bool operator==(const T* aY, const UniquePtr<T, D>& aX) {
+  return aY == aX.get();
+}
+
+template <typename T, class D>
+bool operator!=(const UniquePtr<T, D>& aX, const T* aY) {
+  return aX.get() != aY;
+}
+
+template <typename T, class D>
+bool operator!=(const T* aY, const UniquePtr<T, D>& aX) {
+  return aY != aX.get();
+}
+
 template <typename T, class D>
 bool operator==(const UniquePtr<T, D>& aX, decltype(nullptr)) {
   return !aX;
diff --git a/mfbt/Variant.h b/mfbt/Variant.h
index a21198a2c5..0cb6456d84 100644
--- a/mfbt/Variant.h
+++ b/mfbt/Variant.h
@@ -108,11 +108,11 @@ struct VariantTag {
   static const size_t TypeCount = sizeof...(Ts);
 
  public:
-  using Type = typename Conditional < TypeCount < 3, bool,
-        typename Conditional<TypeCount<(1 << 8), uint_fast8_t,
-                                       size_t  // stop caring past a certain
-                                               // point :-)
-                                       >::Type>::Type;
+  using Type = std::conditional_t < TypeCount < 3, bool,
+        std::conditional_t<TypeCount<(1 << 8), uint_fast8_t,
+                                     size_t  // stop caring past a certain
+                                             // point :-)
+                                     >>;
 };
 
 // TagHelper gets the given sentinel tag value for the given type T. This has to
diff --git a/mfbt/Vector.h b/mfbt/Vector.h
index 72a28c7491..673fa9aac3 100644
--- a/mfbt/Vector.h
+++ b/mfbt/Vector.h
@@ -7,6 +7,9 @@
 #ifndef mozilla_Vector_h
 #define mozilla_Vector_h
 
+#include <new>  // for placement new
+#include <utility>
+
 #include "mozilla/Alignment.h"
 #include "mozilla/AllocPolicy.h"
 #include "mozilla/ArrayUtils.h"  // for PointerRangeSize
@@ -14,14 +17,11 @@
 #include "mozilla/Attributes.h"
 #include "mozilla/MathAlgorithms.h"
 #include "mozilla/MemoryReporting.h"
-#include "mozilla/Move.h"
 #include "mozilla/OperatorNewExtensions.h"
 #include "mozilla/ReentrancyGuard.h"
+#include "mozilla/Span.h"
 #include "mozilla/TemplateLib.h"
 #include "mozilla/TypeTraits.h"
-#include "mozilla/Span.h"
-
-#include <new>  // for placement new
 
 namespace mozilla {
 
@@ -897,7 +897,7 @@ MOZ_ALWAYS_INLINE void Vector<T, N, AP>::reverse() {
   size_t len = mLength;
   size_t mid = len / 2;
   for (size_t i = 0; i < mid; i++) {
-    Swap(elems[i], elems[len - i - 1]);
+    std::swap(elems[i], elems[len - i - 1]);
   }
 }
 
@@ -1528,15 +1528,15 @@ inline void Vector<T, N, AP>::swap(Vector& aOther) {
     mBegin = aOther.mBegin;
     aOther.mBegin = aOther.inlineStorage();
   } else if (!usingInlineStorage() && !aOther.usingInlineStorage()) {
-    Swap(mBegin, aOther.mBegin);
+    std::swap(mBegin, aOther.mBegin);
   } else {
     // This case is a no-op, since we'd set both to use their inline storage.
   }
 
-  Swap(mLength, aOther.mLength);
-  Swap(mTail.mCapacity, aOther.mTail.mCapacity);
+  std::swap(mLength, aOther.mLength);
+  std::swap(mTail.mCapacity, aOther.mTail.mCapacity);
 #ifdef DEBUG
-  Swap(mTail.mReserved, aOther.mTail.mReserved);
+  std::swap(mTail.mReserved, aOther.mTail.mReserved);
 #endif
 }
 
diff --git a/mfbt/moz.build b/mfbt/moz.build
index c3ffe9bfc9..4258762122 100644
--- a/mfbt/moz.build
+++ b/mfbt/moz.build
@@ -29,6 +29,7 @@ EXPORTS.mozilla = [
     'ChaosMode.h',
     'Char16.h',
     'CheckedInt.h',
+    'CompactPair.h',
     'Compiler.h',
     'Compression.h',
     'DbgMacro.h',
@@ -72,7 +73,6 @@ EXPORTS.mozilla = [
     'NullPtr.h',
     'Opaque.h',
     'OperatorNewExtensions.h',
-    'Pair.h',
     'Path.h',
     'PodOperations.h',
     'Poison.h',
diff --git a/mfbt/tests/TestCompactPair.cpp b/mfbt/tests/TestCompactPair.cpp
new file mode 100644
index 0000000000..a6737c109e
--- /dev/null
+++ b/mfbt/tests/TestCompactPair.cpp
@@ -0,0 +1,158 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <type_traits>
+
+#include "mozilla/Assertions.h"
+#include "mozilla/CompactPair.h"
+
+using mozilla::CompactPair;
+using mozilla::MakeCompactPair;
+
+// Sizes aren't part of the guaranteed CompactPair interface, but we want to
+// verify our attempts at compactness through EBO are moderately functional,
+// *somewhere*.
+#define INSTANTIATE(T1, T2, name, size)                                        \
+  CompactPair<T1, T2> name##_1(T1(0), T2(0));                                  \
+  static_assert(sizeof(name##_1.first()) > 0,                                  \
+                "first method should work on CompactPair<" #T1 ", " #T2 ">");  \
+                                                                               \
+  static_assert(sizeof(name##_1.second()) > 0,                                 \
+                "second method should work on CompactPair<" #T1 ", " #T2 ">"); \
+                                                                               \
+  static_assert(sizeof(name##_1) == (size),                                    \
+                "CompactPair<" #T1 ", " #T2 "> has an unexpected size");       \
+                                                                               \
+  CompactPair<T2, T1> name##_2(T2(0), T1(0));                                  \
+  static_assert(sizeof(name##_2.first()) > 0,                                  \
+                "first method should work on CompactPair<" #T2 ", " #T1 ">");  \
+                                                                               \
+  static_assert(sizeof(name##_2.second()) > 0,                                 \
+                "second method should work on CompactPair<" #T2 ", " #T1 ">"); \
+                                                                               \
+  static_assert(sizeof(name##_2) == (size),                                    \
+                "CompactPair<" #T2 ", " #T1 "> has an unexpected size");
+
+static constexpr std::size_t sizemax(std::size_t a, std::size_t b) {
+  return (a > b) ? a : b;
+}
+
+INSTANTIATE(int, int, prim1, 2 * sizeof(int));
+INSTANTIATE(int, long, prim2,
+            sizeof(long) + sizemax(sizeof(int), alignof(long)));
+
+struct EmptyClass {
+  explicit EmptyClass(int) {}
+};
+struct NonEmpty {
+  char mC;
+  explicit NonEmpty(int) : mC('\0') {}
+};
+
+INSTANTIATE(int, EmptyClass, both1, sizeof(int));
+INSTANTIATE(int, NonEmpty, both2, sizeof(int) + alignof(int));
+INSTANTIATE(EmptyClass, NonEmpty, both3, 1);
+
+struct A {
+  char dummy;
+  explicit A(int) : dummy('\0') {}
+};
+struct B : A {
+  explicit B(int aI) : A(aI) {}
+};
+
+INSTANTIATE(A, A, class1, 2);
+INSTANTIATE(A, B, class2, 2);
+INSTANTIATE(A, EmptyClass, class3, 1);
+
+struct EmptyNonMovableNonDefaultConstructible {
+  explicit EmptyNonMovableNonDefaultConstructible(int) {}
+
+  EmptyNonMovableNonDefaultConstructible(
+      const EmptyNonMovableNonDefaultConstructible&) = delete;
+  EmptyNonMovableNonDefaultConstructible(
+      EmptyNonMovableNonDefaultConstructible&&) = delete;
+  EmptyNonMovableNonDefaultConstructible& operator=(
+      const EmptyNonMovableNonDefaultConstructible&) = delete;
+  EmptyNonMovableNonDefaultConstructible& operator=(
+      EmptyNonMovableNonDefaultConstructible&&) = delete;
+};
+
+static void TestInPlaceConstruction() {
+  constexpr int firstValue = 42;
+  constexpr int secondValue = 43;
+
+  {
+    const CompactPair<EmptyNonMovableNonDefaultConstructible, int> pair{
+        std::piecewise_construct, std::tuple(firstValue),
+        std::tuple(secondValue)};
+    MOZ_RELEASE_ASSERT(pair.second() == secondValue);
+  }
+
+  {
+    const CompactPair<int, EmptyNonMovableNonDefaultConstructible> pair{
+        std::piecewise_construct, std::tuple(firstValue),
+        std::tuple(secondValue)};
+    MOZ_RELEASE_ASSERT(pair.first() == firstValue);
+  }
+
+  {
+    const CompactPair<int, int> pair{std::piecewise_construct,
+                                     std::tuple(firstValue),
+                                     std::tuple(secondValue)};
+    MOZ_RELEASE_ASSERT(pair.first() == firstValue);
+    MOZ_RELEASE_ASSERT(pair.second() == secondValue);
+  }
+
+  {
+    const CompactPair<EmptyNonMovableNonDefaultConstructible,
+                      EmptyNonMovableNonDefaultConstructible>
+        pair{std::piecewise_construct, std::tuple(firstValue),
+             std::tuple(secondValue)};
+
+    // nothing to assert here...
+  }
+}
+
+struct OtherEmpty : EmptyClass {
+  explicit OtherEmpty(int aI) : EmptyClass(aI) {}
+};
+
+// C++11 requires distinct objects of the same type, within the same "most
+// derived object", to have different addresses.  CompactPair allocates its
+// elements as two bases, a base and a member, or two members.  If the two
+// elements have non-zero size or are unrelated, no big deal.  But if they're
+// both empty and related, something -- possibly both -- must be inflated.
+// Exactly which are inflated depends which CompactPairHelper specialization is
+// used.  We could potentially assert something about size for this case, but
+// whatever we could assert would be very finicky.  Plus it's two empty classes
+// -- hardly likely. So don't bother trying to assert anything about this case.
+// INSTANTIATE(EmptyClass, OtherEmpty, class4, ...something finicky...);
+
+int main() {
+  A a(0);
+  B b(0);
+  const A constA(0);
+  const B constB(0);
+
+  // Check that MakeCompactPair generates CompactPair objects of the correct
+  // types.
+  static_assert(
+      std::is_same_v<decltype(MakeCompactPair(A(0), B(0))), CompactPair<A, B>>,
+      "MakeCompactPair should strip rvalue references");
+  static_assert(
+      std::is_same_v<decltype(MakeCompactPair(a, b)), CompactPair<A, B>>,
+      "MakeCompactPair should strip lvalue references");
+  static_assert(std::is_same_v<decltype(MakeCompactPair(constA, constB)),
+                               CompactPair<A, B>>,
+                "MakeCompactPair should strip CV-qualifiers");
+
+  // Check that copy assignment and move assignment work.
+  a = constA;
+  a = A(0);
+
+  TestInPlaceConstruction();
+
+  return 0;
+}
diff --git a/mfbt/tests/TestFunctionRef.cpp b/mfbt/tests/TestFunctionRef.cpp
index 75ea2de8f5..811d89f85d 100644
--- a/mfbt/tests/TestFunctionRef.cpp
+++ b/mfbt/tests/TestFunctionRef.cpp
@@ -4,6 +4,7 @@
 
 #include "mozilla/Assertions.h"
 #include "mozilla/FunctionRef.h"
+#include "mozilla/UniquePtr.h"
 
 #define CHECK(c)                                       \
   do {                                                 \
@@ -17,6 +18,8 @@ void incrementPointer(int* arg) { (*arg)++; }
 
 int increment(int arg) { return arg + 1; }
 
+int incrementUnique(mozilla::UniquePtr<int> ptr) { return *ptr + 1; }
+
 static bool helloWorldCalled = false;
 
 void helloWorld() { helloWorldCalled = true; }
@@ -112,6 +115,12 @@ static void TestImplicitFunctionPointerTypeConversion() {
   CHECK(f(x) == 2);
 }
 
+static void TestMoveOnlyArguments() {
+  mozilla::FunctionRef<int(mozilla::UniquePtr<int>)> f(&incrementUnique);
+
+  CHECK(f(mozilla::MakeUnique<int>(5)) == 6);
+}
+
 int main() {
   TestNonmemberFunction();
   TestStaticMemberFunction();
@@ -124,6 +133,7 @@ int main() {
   TestImplicitFunctorTypeConversion();
   TestImplicitLambdaTypeConversion();
   TestImplicitFunctionPointerTypeConversion();
+  TestMoveOnlyArguments();
 
   printf("TestFunctionRef OK!\n");
   return 0;
diff --git a/mfbt/tests/TestLinkedList.cpp b/mfbt/tests/TestLinkedList.cpp
index 9c99ecb1f2..42d0078276 100644
--- a/mfbt/tests/TestLinkedList.cpp
+++ b/mfbt/tests/TestLinkedList.cpp
@@ -31,6 +31,7 @@ static void TestList() {
   SomeClass one(1), two(2), three(3);
 
   MOZ_RELEASE_ASSERT(list.isEmpty());
+  MOZ_RELEASE_ASSERT(list.length() == 0);
   MOZ_RELEASE_ASSERT(!list.getFirst());
   MOZ_RELEASE_ASSERT(!list.getLast());
   MOZ_RELEASE_ASSERT(!list.popFirst());
@@ -51,7 +52,12 @@ static void TestList() {
   MOZ_RELEASE_ASSERT(!two.isInList());
   MOZ_RELEASE_ASSERT(!three.isInList());
 
+  MOZ_RELEASE_ASSERT(list.contains(&one));
+  MOZ_RELEASE_ASSERT(!list.contains(&two));
+  MOZ_RELEASE_ASSERT(!list.contains(&three));
+
   MOZ_RELEASE_ASSERT(!list.isEmpty());
+  MOZ_RELEASE_ASSERT(list.length() == 1);
   MOZ_RELEASE_ASSERT(list.getFirst()->mValue == 1);
   MOZ_RELEASE_ASSERT(list.getLast()->mValue == 1);
 
@@ -61,6 +67,7 @@ static void TestList() {
     CheckListValues(list, check);
   }
 
+  MOZ_RELEASE_ASSERT(list.length() == 2);
   MOZ_RELEASE_ASSERT(list.getFirst()->mValue == 2);
   MOZ_RELEASE_ASSERT(list.getLast()->mValue == 1);
 
@@ -70,6 +77,7 @@ static void TestList() {
     CheckListValues(list, check);
   }
 
+  MOZ_RELEASE_ASSERT(list.length() == 3);
   MOZ_RELEASE_ASSERT(list.getFirst()->mValue == 2);
   MOZ_RELEASE_ASSERT(list.getLast()->mValue == 3);
 
@@ -151,6 +159,7 @@ static void TestList() {
     x->incr();
   }
 
+  MOZ_RELEASE_ASSERT(list.length() == 2);
   MOZ_RELEASE_ASSERT(list.getFirst() == &two);
   MOZ_RELEASE_ASSERT(list.getLast() == &three);
   MOZ_RELEASE_ASSERT(list.getFirst()->mValue == 3);
diff --git a/mfbt/tests/TestMaybe.cpp b/mfbt/tests/TestMaybe.cpp
index 52446e23d6..ac81de95ba 100644
--- a/mfbt/tests/TestMaybe.cpp
+++ b/mfbt/tests/TestMaybe.cpp
@@ -2,26 +2,23 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
  * You can obtain one at http://mozilla.org/MPL/2.0/. */
 
+#include <type_traits>
 #include <utility>
 
 #include "mozilla/Assertions.h"
 #include "mozilla/Attributes.h"
 #include "mozilla/Compiler.h"
 #include "mozilla/Maybe.h"
-#include "mozilla/Move.h"
 #include "mozilla/TemplateLib.h"
-#include "mozilla/Types.h"
 #include "mozilla/TypeTraits.h"
+#include "mozilla/Types.h"
 #include "mozilla/UniquePtr.h"
 
-using mozilla::IsSame;
 using mozilla::Maybe;
 using mozilla::Nothing;
 using mozilla::Some;
 using mozilla::SomeRef;
-using mozilla::Swap;
 using mozilla::ToMaybe;
-using mozilla::UniquePtr;
 
 #define RUN_TEST(t)                                                     \
   do {                                                                  \
@@ -159,7 +156,7 @@ struct UncopyableUnmovableValue {
 
   ~UncopyableUnmovableValue() { --sUndestroyedObjects; }
 
-  Status GetStatus() { return mStatus; }
+  Status GetStatus() const { return mStatus; }
 
  private:
   UncopyableUnmovableValue(const UncopyableUnmovableValue& aOther) = delete;
@@ -172,7 +169,7 @@ struct UncopyableUnmovableValue {
   Status mStatus;
 };
 
-static_assert(std::is_literal_type_v<Maybe<int>>);
+static_assert(std::is_trivially_destructible_v<Maybe<int>>);
 static_assert(std::is_trivially_copy_constructible_v<Maybe<int>>);
 static_assert(std::is_trivially_copy_assignable_v<Maybe<int>>);
 
@@ -187,6 +184,10 @@ static_assert(Some(43) == [] {
   return val;
 }());
 static_assert(Some(43) == Some(42).map([](int val) { return val + 1; }));
+static_assert(Maybe<int>(std::in_place, 43) ==
+              Maybe<int>(std::in_place, 42).map([](int val) {
+                return val + 1;
+              }));
 
 struct TriviallyDestructible {
   TriviallyDestructible() {  // not trivially constructible
@@ -195,10 +196,39 @@ struct TriviallyDestructible {
 
 static_assert(std::is_trivially_destructible_v<Maybe<TriviallyDestructible>>);
 
+struct UncopyableValueLiteralType {
+  explicit constexpr UncopyableValueLiteralType(int aValue) : mValue{aValue} {}
+
+  UncopyableValueLiteralType(UncopyableValueLiteralType&&) = default;
+  UncopyableValueLiteralType& operator=(UncopyableValueLiteralType&&) = default;
+
+  int mValue;
+};
+
+static_assert(
+    std::is_trivially_destructible_v<Maybe<UncopyableValueLiteralType>>);
+static_assert(!std::is_copy_constructible_v<Maybe<UncopyableValueLiteralType>>);
+static_assert(!std::is_copy_assignable_v<Maybe<UncopyableValueLiteralType>>);
+static_assert(std::is_move_constructible_v<Maybe<UncopyableValueLiteralType>>);
+static_assert(std::is_move_assignable_v<Maybe<UncopyableValueLiteralType>>);
+
+constexpr Maybe<UncopyableValueLiteralType> someUncopyable =
+    Some(UncopyableValueLiteralType{42});
+static_assert(someUncopyable.isSome());
+static_assert(42 == someUncopyable->mValue);
+
+constexpr Maybe<UncopyableValueLiteralType> someUncopyableAssigned = [] {
+  auto res = Maybe<UncopyableValueLiteralType>{};
+  res = Some(UncopyableValueLiteralType{42});
+  return res;
+}();
+static_assert(someUncopyableAssigned.isSome());
+static_assert(42 == someUncopyableAssigned->mValue);
+
 static bool TestBasicFeatures() {
   // Check that a Maybe<T> is initialized to Nothing.
   Maybe<BasicValue> mayValue;
-  static_assert(IsSame<BasicValue, decltype(mayValue)::ValueType>::value,
+  static_assert(std::is_same_v<BasicValue, decltype(mayValue)::ValueType>,
                 "Should have BasicValue ValueType");
   MOZ_RELEASE_ASSERT(!mayValue);
   MOZ_RELEASE_ASSERT(!mayValue.isSome());
@@ -211,13 +241,13 @@ static bool TestBasicFeatures() {
   MOZ_RELEASE_ASSERT(!mayValue.isNothing());
   MOZ_RELEASE_ASSERT(*mayValue == BasicValue());
   MOZ_RELEASE_ASSERT(mayValue.value() == BasicValue());
-  static_assert(IsSame<BasicValue, decltype(mayValue.value())>::value,
+  static_assert(std::is_same_v<BasicValue, decltype(mayValue.value())>,
                 "value() should return a BasicValue");
   MOZ_RELEASE_ASSERT(mayValue.ref() == BasicValue());
-  static_assert(IsSame<BasicValue&, decltype(mayValue.ref())>::value,
+  static_assert(std::is_same_v<BasicValue&, decltype(mayValue.ref())>,
                 "ref() should return a BasicValue&");
   MOZ_RELEASE_ASSERT(mayValue.ptr() != nullptr);
-  static_assert(IsSame<BasicValue*, decltype(mayValue.ptr())>::value,
+  static_assert(std::is_same_v<BasicValue*, decltype(mayValue.ptr())>,
                 "ptr() should return a BasicValue*");
   MOZ_RELEASE_ASSERT(mayValue->GetStatus() == eWasDefaultConstructed);
 
@@ -235,6 +265,14 @@ static bool TestBasicFeatures() {
   mayValue.reset();
   MOZ_RELEASE_ASSERT(!mayValue);
 
+  {
+    // Check that Maybe(std::in_place, T1) calls the correct constructor.
+    const auto mayValueConstructed = Maybe<BasicValue>(std::in_place, 1);
+    MOZ_RELEASE_ASSERT(mayValueConstructed);
+    MOZ_RELEASE_ASSERT(mayValueConstructed->GetStatus() == eWasConstructed);
+    MOZ_RELEASE_ASSERT(mayValueConstructed->GetTag() == 1);
+  }
+
   // Check that Some() and Nothing() work.
   mayValue = Some(BasicValue(2));
   MOZ_RELEASE_ASSERT(mayValue);
@@ -251,13 +289,13 @@ static bool TestBasicFeatures() {
   MOZ_RELEASE_ASSERT(!mayValueCRef.isNothing());
   MOZ_RELEASE_ASSERT(*mayValueCRef == BasicValue());
   MOZ_RELEASE_ASSERT(mayValueCRef.value() == BasicValue());
-  static_assert(IsSame<BasicValue, decltype(mayValueCRef.value())>::value,
+  static_assert(std::is_same_v<BasicValue, decltype(mayValueCRef.value())>,
                 "value() should return a BasicValue");
   MOZ_RELEASE_ASSERT(mayValueCRef.ref() == BasicValue());
-  static_assert(IsSame<const BasicValue&, decltype(mayValueCRef.ref())>::value,
+  static_assert(std::is_same_v<const BasicValue&, decltype(mayValueCRef.ref())>,
                 "ref() should return a const BasicValue&");
   MOZ_RELEASE_ASSERT(mayValueCRef.ptr() != nullptr);
-  static_assert(IsSame<const BasicValue*, decltype(mayValueCRef.ptr())>::value,
+  static_assert(std::is_same_v<const BasicValue*, decltype(mayValueCRef.ptr())>,
                 "ptr() should return a const BasicValue*");
   MOZ_RELEASE_ASSERT(mayValueCRef->GetStatus() == eWasDefaultConstructed);
   mayValue.reset();
@@ -276,6 +314,21 @@ static bool TestBasicFeatures() {
   MOZ_RELEASE_ASSERT(mayCValue2.isSome());
   MOZ_RELEASE_ASSERT(*mayCValue2 == BasicValue(6));
 
+  // Check that take works
+  mayValue = Some(BasicValue(6));
+  Maybe taken = mayValue.take();
+  MOZ_RELEASE_ASSERT(taken->GetStatus() == eWasMoveConstructed);
+  MOZ_RELEASE_ASSERT(taken == Some(BasicValue(6)));
+  MOZ_RELEASE_ASSERT(!mayValue.isSome());
+  MOZ_RELEASE_ASSERT(mayValue.take() == Nothing());
+
+  // Check that extract works
+  mayValue = Some(BasicValue(7));
+  BasicValue extracted = mayValue.extract();
+  MOZ_RELEASE_ASSERT(extracted.GetStatus() == eWasMoveConstructed);
+  MOZ_RELEASE_ASSERT(extracted == BasicValue(7));
+  MOZ_RELEASE_ASSERT(!mayValue.isSome());
+
   return true;
 }
 
@@ -325,6 +378,26 @@ static void TestMoveMaybe() {
     MOZ_RELEASE_ASSERT(1 == sUndestroyedObjects);
     MOZ_RELEASE_ASSERT(dstMoveAssigned->GetStatus() == eWasMoveConstructed);
   }
+
+  {
+    MOZ_RELEASE_ASSERT(0 == sUndestroyedObjects);
+
+    Maybe<T> src = Some(T());
+    Maybe<T> dstMoveConstructed = src.take();
+
+    MOZ_RELEASE_ASSERT(1 == sUndestroyedObjects);
+    MOZ_RELEASE_ASSERT(dstMoveConstructed->GetStatus() == eWasMoveConstructed);
+  }
+
+  {
+    MOZ_RELEASE_ASSERT(0 == sUndestroyedObjects);
+
+    Maybe<T> src = Some(T());
+    T dstMoveConstructed = src.extract();
+
+    MOZ_RELEASE_ASSERT(1 == sUndestroyedObjects);
+    MOZ_RELEASE_ASSERT(dstMoveConstructed.GetStatus() == eWasMoveConstructed);
+  }
 }
 
 static bool TestCopyAndMove() {
@@ -436,6 +509,13 @@ static bool TestCopyAndMove() {
   MOZ_RELEASE_ASSERT(0 == sUndestroyedObjects);
 
   {  // Check that types that support neither moves or copies work.
+    {
+      const auto mayUncopyableUnmovableValueConstructed =
+          Maybe<UncopyableUnmovableValue>{std::in_place};
+      MOZ_RELEASE_ASSERT(mayUncopyableUnmovableValueConstructed->GetStatus() ==
+                         eWasDefaultConstructed);
+    }
+
     Maybe<UncopyableUnmovableValue> mayUncopyableUnmovableValue;
     mayUncopyableUnmovableValue.emplace();
     MOZ_RELEASE_ASSERT(mayUncopyableUnmovableValue->GetStatus() ==
@@ -517,119 +597,121 @@ static bool TestFunctionalAccessors() {
   // Check that the 'some' case of functional accessors works.
   Maybe<BasicValue> someValue = Some(BasicValue(3));
   MOZ_RELEASE_ASSERT(someValue.valueOr(value) == BasicValue(3));
-  static_assert(IsSame<BasicValue, decltype(someValue.valueOr(value))>::value,
+  static_assert(std::is_same_v<BasicValue, decltype(someValue.valueOr(value))>,
                 "valueOr should return a BasicValue");
   MOZ_RELEASE_ASSERT(someValue.valueOrFrom(&MakeBasicValue) == BasicValue(3));
-  static_assert(IsSame<BasicValue,
-                       decltype(someValue.valueOrFrom(&MakeBasicValue))>::value,
-                "valueOrFrom should return a BasicValue");
+  static_assert(
+      std::is_same_v<BasicValue,
+                     decltype(someValue.valueOrFrom(&MakeBasicValue))>,
+      "valueOrFrom should return a BasicValue");
   MOZ_RELEASE_ASSERT(someValue.ptrOr(&value) != &value);
-  static_assert(IsSame<BasicValue*, decltype(someValue.ptrOr(&value))>::value,
+  static_assert(std::is_same_v<BasicValue*, decltype(someValue.ptrOr(&value))>,
                 "ptrOr should return a BasicValue*");
   MOZ_RELEASE_ASSERT(*someValue.ptrOrFrom(&MakeBasicValuePtr) == BasicValue(3));
   static_assert(
-      IsSame<BasicValue*,
-             decltype(someValue.ptrOrFrom(&MakeBasicValuePtr))>::value,
+      std::is_same_v<BasicValue*,
+                     decltype(someValue.ptrOrFrom(&MakeBasicValuePtr))>,
       "ptrOrFrom should return a BasicValue*");
   MOZ_RELEASE_ASSERT(someValue.refOr(value) == BasicValue(3));
-  static_assert(IsSame<BasicValue&, decltype(someValue.refOr(value))>::value,
+  static_assert(std::is_same_v<BasicValue&, decltype(someValue.refOr(value))>,
                 "refOr should return a BasicValue&");
   MOZ_RELEASE_ASSERT(someValue.refOrFrom(&MakeBasicValueRef) == BasicValue(3));
   static_assert(
-      IsSame<BasicValue&,
-             decltype(someValue.refOrFrom(&MakeBasicValueRef))>::value,
+      std::is_same_v<BasicValue&,
+                     decltype(someValue.refOrFrom(&MakeBasicValueRef))>,
       "refOrFrom should return a BasicValue&");
 
   // Check that the 'some' case works through a const reference.
   const Maybe<BasicValue>& someValueCRef = someValue;
   MOZ_RELEASE_ASSERT(someValueCRef.valueOr(value) == BasicValue(3));
   static_assert(
-      IsSame<BasicValue, decltype(someValueCRef.valueOr(value))>::value,
+      std::is_same_v<BasicValue, decltype(someValueCRef.valueOr(value))>,
       "valueOr should return a BasicValue");
   MOZ_RELEASE_ASSERT(someValueCRef.valueOrFrom(&MakeBasicValue) ==
                      BasicValue(3));
   static_assert(
-      IsSame<BasicValue,
-             decltype(someValueCRef.valueOrFrom(&MakeBasicValue))>::value,
+      std::is_same_v<BasicValue,
+                     decltype(someValueCRef.valueOrFrom(&MakeBasicValue))>,
       "valueOrFrom should return a BasicValue");
   MOZ_RELEASE_ASSERT(someValueCRef.ptrOr(&value) != &value);
   static_assert(
-      IsSame<const BasicValue*, decltype(someValueCRef.ptrOr(&value))>::value,
+      std::is_same_v<const BasicValue*, decltype(someValueCRef.ptrOr(&value))>,
       "ptrOr should return a const BasicValue*");
   MOZ_RELEASE_ASSERT(*someValueCRef.ptrOrFrom(&MakeBasicValuePtr) ==
                      BasicValue(3));
   static_assert(
-      IsSame<const BasicValue*,
-             decltype(someValueCRef.ptrOrFrom(&MakeBasicValuePtr))>::value,
+      std::is_same_v<const BasicValue*,
+                     decltype(someValueCRef.ptrOrFrom(&MakeBasicValuePtr))>,
       "ptrOrFrom should return a const BasicValue*");
   MOZ_RELEASE_ASSERT(someValueCRef.refOr(value) == BasicValue(3));
   static_assert(
-      IsSame<const BasicValue&, decltype(someValueCRef.refOr(value))>::value,
+      std::is_same_v<const BasicValue&, decltype(someValueCRef.refOr(value))>,
       "refOr should return a const BasicValue&");
   MOZ_RELEASE_ASSERT(someValueCRef.refOrFrom(&MakeBasicValueRef) ==
                      BasicValue(3));
   static_assert(
-      IsSame<const BasicValue&,
-             decltype(someValueCRef.refOrFrom(&MakeBasicValueRef))>::value,
+      std::is_same_v<const BasicValue&,
+                     decltype(someValueCRef.refOrFrom(&MakeBasicValueRef))>,
       "refOrFrom should return a const BasicValue&");
 
   // Check that the 'none' case of functional accessors works.
   Maybe<BasicValue> noneValue;
   MOZ_RELEASE_ASSERT(noneValue.valueOr(value) == BasicValue(9));
-  static_assert(IsSame<BasicValue, decltype(noneValue.valueOr(value))>::value,
+  static_assert(std::is_same_v<BasicValue, decltype(noneValue.valueOr(value))>,
                 "valueOr should return a BasicValue");
   MOZ_RELEASE_ASSERT(noneValue.valueOrFrom(&MakeBasicValue) == BasicValue(9));
-  static_assert(IsSame<BasicValue,
-                       decltype(noneValue.valueOrFrom(&MakeBasicValue))>::value,
-                "valueOrFrom should return a BasicValue");
+  static_assert(
+      std::is_same_v<BasicValue,
+                     decltype(noneValue.valueOrFrom(&MakeBasicValue))>,
+      "valueOrFrom should return a BasicValue");
   MOZ_RELEASE_ASSERT(noneValue.ptrOr(&value) == &value);
-  static_assert(IsSame<BasicValue*, decltype(noneValue.ptrOr(&value))>::value,
+  static_assert(std::is_same_v<BasicValue*, decltype(noneValue.ptrOr(&value))>,
                 "ptrOr should return a BasicValue*");
   MOZ_RELEASE_ASSERT(*noneValue.ptrOrFrom(&MakeBasicValuePtr) == BasicValue(9));
   static_assert(
-      IsSame<BasicValue*,
-             decltype(noneValue.ptrOrFrom(&MakeBasicValuePtr))>::value,
+      std::is_same_v<BasicValue*,
+                     decltype(noneValue.ptrOrFrom(&MakeBasicValuePtr))>,
       "ptrOrFrom should return a BasicValue*");
   MOZ_RELEASE_ASSERT(noneValue.refOr(value) == BasicValue(9));
-  static_assert(IsSame<BasicValue&, decltype(noneValue.refOr(value))>::value,
+  static_assert(std::is_same_v<BasicValue&, decltype(noneValue.refOr(value))>,
                 "refOr should return a BasicValue&");
   MOZ_RELEASE_ASSERT(noneValue.refOrFrom(&MakeBasicValueRef) == BasicValue(9));
   static_assert(
-      IsSame<BasicValue&,
-             decltype(noneValue.refOrFrom(&MakeBasicValueRef))>::value,
+      std::is_same_v<BasicValue&,
+                     decltype(noneValue.refOrFrom(&MakeBasicValueRef))>,
       "refOrFrom should return a BasicValue&");
 
   // Check that the 'none' case works through a const reference.
   const Maybe<BasicValue>& noneValueCRef = noneValue;
   MOZ_RELEASE_ASSERT(noneValueCRef.valueOr(value) == BasicValue(9));
   static_assert(
-      IsSame<BasicValue, decltype(noneValueCRef.valueOr(value))>::value,
+      std::is_same_v<BasicValue, decltype(noneValueCRef.valueOr(value))>,
       "valueOr should return a BasicValue");
   MOZ_RELEASE_ASSERT(noneValueCRef.valueOrFrom(&MakeBasicValue) ==
                      BasicValue(9));
   static_assert(
-      IsSame<BasicValue,
-             decltype(noneValueCRef.valueOrFrom(&MakeBasicValue))>::value,
+      std::is_same_v<BasicValue,
+                     decltype(noneValueCRef.valueOrFrom(&MakeBasicValue))>,
       "valueOrFrom should return a BasicValue");
   MOZ_RELEASE_ASSERT(noneValueCRef.ptrOr(&value) == &value);
   static_assert(
-      IsSame<const BasicValue*, decltype(noneValueCRef.ptrOr(&value))>::value,
+      std::is_same_v<const BasicValue*, decltype(noneValueCRef.ptrOr(&value))>,
       "ptrOr should return a const BasicValue*");
   MOZ_RELEASE_ASSERT(*noneValueCRef.ptrOrFrom(&MakeBasicValuePtr) ==
                      BasicValue(9));
   static_assert(
-      IsSame<const BasicValue*,
-             decltype(noneValueCRef.ptrOrFrom(&MakeBasicValuePtr))>::value,
+      std::is_same_v<const BasicValue*,
+                     decltype(noneValueCRef.ptrOrFrom(&MakeBasicValuePtr))>,
       "ptrOrFrom should return a const BasicValue*");
   MOZ_RELEASE_ASSERT(noneValueCRef.refOr(value) == BasicValue(9));
   static_assert(
-      IsSame<const BasicValue&, decltype(noneValueCRef.refOr(value))>::value,
+      std::is_same_v<const BasicValue&, decltype(noneValueCRef.refOr(value))>,
       "refOr should return a const BasicValue&");
   MOZ_RELEASE_ASSERT(noneValueCRef.refOrFrom(&MakeBasicValueRef) ==
                      BasicValue(9));
   static_assert(
-      IsSame<const BasicValue&,
-             decltype(noneValueCRef.refOrFrom(&MakeBasicValueRef))>::value,
+      std::is_same_v<const BasicValue&,
+                     decltype(noneValueCRef.refOrFrom(&MakeBasicValueRef))>,
       "refOrFrom should return a const BasicValue&");
 
   // Clean up so the undestroyed objects count stays accurate.
@@ -724,7 +806,7 @@ static bool TestMap() {
   // Check that map handles the 'Nothing' case.
   Maybe<BasicValue> mayValue;
   MOZ_RELEASE_ASSERT(mayValue.map(&TimesTwo) == Nothing());
-  static_assert(IsSame<Maybe<int>, decltype(mayValue.map(&TimesTwo))>::value,
+  static_assert(std::is_same_v<Maybe<int>, decltype(mayValue.map(&TimesTwo))>,
                 "map(TimesTwo) should return a Maybe<int>");
   MOZ_RELEASE_ASSERT(mayValue.map(&TimesTwoAndResetOriginal) == Nothing());
 
@@ -740,7 +822,7 @@ static bool TestMap() {
   const Maybe<BasicValue>& mayValueCRef = mayValue;
   MOZ_RELEASE_ASSERT(mayValueCRef.map(&TimesTwo) == Some(4));
   static_assert(
-      IsSame<Maybe<int>, decltype(mayValueCRef.map(&TimesTwo))>::value,
+      std::is_same_v<Maybe<int>, decltype(mayValueCRef.map(&TimesTwo))>,
       "map(TimesTwo) should return a Maybe<int>");
 
   // Check that map works with functors.
@@ -816,7 +898,7 @@ static bool TestToMaybe() {
 
   // Check that a non-null pointer translates into a Some value.
   Maybe<BasicValue> mayValue = ToMaybe(&value);
-  static_assert(IsSame<Maybe<BasicValue>, decltype(ToMaybe(&value))>::value,
+  static_assert(std::is_same_v<Maybe<BasicValue>, decltype(ToMaybe(&value))>,
                 "ToMaybe should return a Maybe<BasicValue>");
   MOZ_RELEASE_ASSERT(mayValue.isSome());
   MOZ_RELEASE_ASSERT(mayValue->GetTag() == 1);
@@ -826,7 +908,7 @@ static bool TestToMaybe() {
   // Check that a null pointer translates into a Nothing value.
   mayValue = ToMaybe(nullPointer);
   static_assert(
-      IsSame<Maybe<BasicValue>, decltype(ToMaybe(nullPointer))>::value,
+      std::is_same_v<Maybe<BasicValue>, decltype(ToMaybe(nullPointer))>,
       "ToMaybe should return a Maybe<BasicValue>");
   MOZ_RELEASE_ASSERT(mayValue.isNothing());
 
@@ -1159,10 +1241,13 @@ static bool TestTypeConversion() {
 }
 
 static bool TestReference() {
-  static_assert(std::is_literal_type_v<Maybe<int&>>);
+  static_assert(std::is_trivially_destructible_v<Maybe<int&>>);
   static_assert(std::is_trivially_copy_constructible_v<Maybe<int&>>);
   static_assert(std::is_trivially_copy_assignable_v<Maybe<int&>>);
 
+  static_assert(Maybe<int&>{}.isNothing());
+  static_assert(Maybe<int&>{Nothing{}}.isNothing());
+
   {
     Maybe<int&> defaultConstructed;
 
@@ -1180,7 +1265,7 @@ static bool TestReference() {
   }
 
   {
-    int foo = 42;
+    int foo = 42, bar = 42;
     Maybe<int&> some = SomeRef(foo);
 
     MOZ_RELEASE_ASSERT(!some.isNothing());
@@ -1188,6 +1273,12 @@ static bool TestReference() {
     MOZ_RELEASE_ASSERT(some);
     MOZ_RELEASE_ASSERT(&some.ref() == &foo);
 
+    MOZ_RELEASE_ASSERT(some.refEquals(foo));
+    MOZ_RELEASE_ASSERT(some.refEquals(SomeRef(foo)));
+    MOZ_RELEASE_ASSERT(!some.refEquals(Nothing()));
+    MOZ_RELEASE_ASSERT(!some.refEquals(bar));
+    MOZ_RELEASE_ASSERT(!some.refEquals(SomeRef(bar)));
+
     some.ref()++;
     MOZ_RELEASE_ASSERT(43 == foo);
 
@@ -1196,7 +1287,7 @@ static bool TestReference() {
   }
 
   {
-    int foo = 42;
+    int foo = 42, bar = 42;
     Maybe<int&> some;
     some.emplace(foo);
 
@@ -1205,6 +1296,12 @@ static bool TestReference() {
     MOZ_RELEASE_ASSERT(some);
     MOZ_RELEASE_ASSERT(&some.ref() == &foo);
 
+    MOZ_RELEASE_ASSERT(some.refEquals(foo));
+    MOZ_RELEASE_ASSERT(some.refEquals(SomeRef(foo)));
+    MOZ_RELEASE_ASSERT(!some.refEquals(Nothing()));
+    MOZ_RELEASE_ASSERT(!some.refEquals(bar));
+    MOZ_RELEASE_ASSERT(!some.refEquals(SomeRef(bar)));
+
     some.ref()++;
     MOZ_RELEASE_ASSERT(43 == foo);
   }
diff --git a/mfbt/tests/TestNonDereferenceable.cpp b/mfbt/tests/TestNonDereferenceable.cpp
index 9cc4246c4b..3cff4231f2 100644
--- a/mfbt/tests/TestNonDereferenceable.cpp
+++ b/mfbt/tests/TestNonDereferenceable.cpp
@@ -2,10 +2,10 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
  * You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-#include "mozilla/NonDereferenceable.h"
+#include <utility>
 
 #include "mozilla/Assertions.h"
-#include "mozilla/Move.h"
+#include "mozilla/NonDereferenceable.h"
 
 using mozilla::NonDereferenceable;
 
diff --git a/mfbt/tests/TestPair.cpp b/mfbt/tests/TestPair.cpp
deleted file mode 100644
index 764c928c54..0000000000
--- a/mfbt/tests/TestPair.cpp
+++ /dev/null
@@ -1,91 +0,0 @@
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this file,
- * You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-#include "mozilla/Pair.h"
-#include "mozilla/TypeTraits.h"
-
-using mozilla::IsSame;
-using mozilla::MakePair;
-using mozilla::Pair;
-
-// Sizes aren't part of the guaranteed Pair interface, but we want to verify our
-// attempts at compactness through EBO are moderately functional, *somewhere*.
-#define INSTANTIATE(T1, T2, name, size)                                 \
-  Pair<T1, T2> name##_1(T1(0), T2(0));                                  \
-  static_assert(sizeof(name##_1.first()) > 0,                           \
-                "first method should work on Pair<" #T1 ", " #T2 ">");  \
-  static_assert(sizeof(name##_1.second()) > 0,                          \
-                "second method should work on Pair<" #T1 ", " #T2 ">"); \
-  static_assert(sizeof(name##_1) == (size),                             \
-                "Pair<" #T1 ", " #T2 "> has an unexpected size");       \
-  Pair<T2, T1> name##_2(T2(0), T1(0));                                  \
-  static_assert(sizeof(name##_2.first()) > 0,                           \
-                "first method should work on Pair<" #T2 ", " #T1 ">");  \
-  static_assert(sizeof(name##_2.second()) > 0,                          \
-                "second method should work on Pair<" #T2 ", " #T1 ">"); \
-  static_assert(sizeof(name##_2) == (size),                             \
-                "Pair<" #T2 ", " #T1 "> has an unexpected size");
-
-INSTANTIATE(int, int, prim1, 2 * sizeof(int));
-INSTANTIATE(int, long, prim2, 2 * sizeof(long));
-
-struct EmptyClass {
-  explicit EmptyClass(int) {}
-};
-struct NonEmpty {
-  char mC;
-  explicit NonEmpty(int) : mC('\0') {}
-};
-
-INSTANTIATE(int, EmptyClass, both1, sizeof(int));
-INSTANTIATE(int, NonEmpty, both2, 2 * sizeof(int));
-INSTANTIATE(EmptyClass, NonEmpty, both3, 1);
-
-struct A {
-  char dummy;
-  explicit A(int) : dummy('\0') {}
-};
-struct B : A {
-  explicit B(int aI) : A(aI) {}
-};
-
-INSTANTIATE(A, A, class1, 2);
-INSTANTIATE(A, B, class2, 2);
-INSTANTIATE(A, EmptyClass, class3, 1);
-
-struct OtherEmpty : EmptyClass {
-  explicit OtherEmpty(int aI) : EmptyClass(aI) {}
-};
-
-// C++11 requires distinct objects of the same type, within the same "most
-// derived object", to have different addresses.  Pair allocates its elements as
-// two bases, a base and a member, or two members.  If the two elements have
-// non-zero size or are unrelated, no big deal.  But if they're both empty and
-// related, something -- possibly both -- must be inflated.  Exactly which are
-// inflated depends which PairHelper specialization is used.  We could
-// potentially assert something about size for this case, but whatever we could
-// assert would be very finicky.  Plus it's two empty classes -- hardly likely.
-// So don't bother trying to assert anything about this case.
-// INSTANTIATE(EmptyClass, OtherEmpty, class4, ...something finicky...);
-
-int main() {
-  A a(0);
-  B b(0);
-  const A constA(0);
-  const B constB(0);
-
-  // Check that MakePair generates Pair objects of the correct types.
-  static_assert(IsSame<decltype(MakePair(A(0), B(0))), Pair<A, B>>::value,
-                "MakePair should strip rvalue references");
-  static_assert(IsSame<decltype(MakePair(a, b)), Pair<A, B>>::value,
-                "MakePair should strip lvalue references");
-  static_assert(IsSame<decltype(MakePair(constA, constB)), Pair<A, B>>::value,
-                "MakePair should strip CV-qualifiers");
-
-  // Check that copy assignment and move assignment work.
-  a = constA;
-  a = A(0);
-
-  return 0;
-}
diff --git a/mfbt/tests/TestRange.cpp b/mfbt/tests/TestRange.cpp
index 4ef86475bf..0bcbaf9466 100644
--- a/mfbt/tests/TestRange.cpp
+++ b/mfbt/tests/TestRange.cpp
@@ -3,14 +3,14 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #include "mozilla/Range.h"
-#include "mozilla/TypeTraits.h"
 
-using mozilla::IsConvertible;
+#include <type_traits>
+
 using mozilla::Range;
 
-static_assert(IsConvertible<Range<int>, Range<const int>>::value,
+static_assert(std::is_convertible_v<Range<int>, Range<const int>>,
               "Range should convert into const");
-static_assert(!IsConvertible<Range<const int>, Range<int>>::value,
+static_assert(!std::is_convertible_v<Range<const int>, Range<int>>,
               "Range should not drop const in conversion");
 
 void test_RangeToBoolConversionShouldCompile() {
diff --git a/mfbt/tests/TestResult.cpp b/mfbt/tests/TestResult.cpp
index 29caf6f299..2bae8dcf6b 100644
--- a/mfbt/tests/TestResult.cpp
+++ b/mfbt/tests/TestResult.cpp
@@ -12,13 +12,69 @@ using mozilla::Ok;
 using mozilla::Result;
 using mozilla::UniquePtr;
 
-struct Failed {
-  int x;
+enum struct UnusedZeroEnum : int32_t { Ok = 0, NotOk = 1 };
+
+namespace mozilla::detail {
+template <>
+struct UnusedZero<UnusedZeroEnum> {
+  using StorageType = UnusedZeroEnum;
+
+  static constexpr bool value = true;
+  static constexpr StorageType nullValue = UnusedZeroEnum::Ok;
+
+  static constexpr StorageType GetDefaultValue() {
+    return UnusedZeroEnum::NotOk;
+  }
+
+  static constexpr void AssertValid(StorageType aValue) {}
+  static constexpr const UnusedZeroEnum& Inspect(const StorageType& aValue) {
+    return aValue;
+  }
+  static constexpr UnusedZeroEnum Unwrap(StorageType aValue) { return aValue; }
+  static constexpr StorageType Store(UnusedZeroEnum aValue) { return aValue; }
+};
+}  // namespace mozilla::detail
+
+struct Failed {};
+
+namespace mozilla::detail {
+template <>
+struct UnusedZero<Failed> {
+  using StorageType = uintptr_t;
+
+  static constexpr bool value = true;
+  static constexpr StorageType nullValue = 0;
+  static constexpr StorageType GetDefaultValue() { return 2; }
+
+  static constexpr void AssertValid(StorageType aValue) {}
+  static constexpr Failed Inspect(const StorageType& aValue) {
+    return Failed{};
+  }
+  static constexpr Failed Unwrap(StorageType aValue) { return Failed{}; }
+  static constexpr StorageType Store(Failed aValue) {
+    return GetDefaultValue();
+  }
 };
 
-static_assert(sizeof(Result<Ok, Failed&>) == sizeof(uintptr_t),
+template <>
+struct HasFreeLSB<Failed> {
+  static const bool value = true;
+};
+}  // namespace mozilla::detail
+
+// V is trivially default-constructible, and E has UnusedZero<E>::value == true,
+// for a reference type and for a non-reference type
+static_assert(mozilla::detail::SelectResultImpl<uintptr_t, Failed>::value ==
+              mozilla::detail::PackingStrategy::NullIsOk);
+static_assert(mozilla::detail::SelectResultImpl<Ok, UnusedZeroEnum>::value ==
+              mozilla::detail::PackingStrategy::NullIsOk);
+
+static_assert(std::is_trivially_destructible_v<Result<uintptr_t, Failed>>);
+static_assert(std::is_trivially_destructible_v<Result<Ok, UnusedZeroEnum>>);
+
+static_assert(sizeof(Result<Ok, Failed>) == sizeof(uintptr_t),
               "Result with empty value type should be pointer-sized");
-static_assert(sizeof(Result<int*, Failed&>) == sizeof(uintptr_t),
+static_assert(sizeof(Result<int*, Failed>) == sizeof(uintptr_t),
               "Result with two aligned pointer types should be pointer-sized");
 static_assert(
     sizeof(Result<char*, Failed*>) > sizeof(char*),
@@ -49,25 +105,44 @@ static_assert(sizeof(Foo32) >= sizeof(uintptr_t) ||
                   sizeof(Result<Foo16, Foo32>) <= sizeof(uintptr_t),
               "Result with small types should be pointer-sized");
 
-static GenericErrorResult<Failed&> Fail() {
+static GenericErrorResult<Failed> Fail() {
   static Failed failed;
-  return Err<Failed&>(failed);
+  return Err(failed);
 }
 
-static Result<Ok, Failed&> Task1(bool pass) {
+static GenericErrorResult<UnusedZeroEnum> FailUnusedZeroEnum() {
+  return Err(UnusedZeroEnum::NotOk);
+}
+
+static Result<Ok, Failed> Task1(bool pass) {
   if (!pass) {
     return Fail();  // implicit conversion from GenericErrorResult to Result
   }
   return Ok();
 }
 
-static Result<int, Failed&> Task2(bool pass, int value) {
+static Result<Ok, UnusedZeroEnum> Task1UnusedZeroEnumErr(bool pass) {
+  if (!pass) {
+    return FailUnusedZeroEnum();  // implicit conversion from GenericErrorResult
+                                  // to Result
+  }
+  return Ok();
+}
+
+static Result<int, Failed> Task2(bool pass, int value) {
   MOZ_TRY(
       Task1(pass));  // converts one type of result to another in the error case
   return value;      // implicit conversion from T to Result<T, E>
 }
 
-static Result<int, Failed&> Task3(bool pass1, bool pass2, int value) {
+static Result<int, UnusedZeroEnum> Task2UnusedZeroEnumErr(bool pass,
+                                                          int value) {
+  MOZ_TRY(Task1UnusedZeroEnumErr(
+      pass));    // converts one type of result to another in the error case
+  return value;  // implicit conversion from T to Result<T, E>
+}
+
+static Result<int, Failed> Task3(bool pass1, bool pass2, int value) {
   int x, y;
   MOZ_TRY_VAR(x, Task2(pass1, value));
   MOZ_TRY_VAR(y, Task2(pass2, value));
@@ -80,6 +155,15 @@ static void BasicTests() {
   MOZ_RELEASE_ASSERT(!Task1(false).isOk());
   MOZ_RELEASE_ASSERT(Task1(false).isErr());
 
+  MOZ_RELEASE_ASSERT(Task1UnusedZeroEnumErr(true).isOk());
+  MOZ_RELEASE_ASSERT(!Task1UnusedZeroEnumErr(true).isErr());
+  MOZ_RELEASE_ASSERT(!Task1UnusedZeroEnumErr(false).isOk());
+  MOZ_RELEASE_ASSERT(Task1UnusedZeroEnumErr(false).isErr());
+  MOZ_RELEASE_ASSERT(UnusedZeroEnum::NotOk ==
+                     Task1UnusedZeroEnumErr(false).inspectErr());
+  MOZ_RELEASE_ASSERT(UnusedZeroEnum::NotOk ==
+                     Task1UnusedZeroEnumErr(false).unwrapErr());
+
   // MOZ_TRY works.
   MOZ_RELEASE_ASSERT(Task2(true, 3).isOk());
   MOZ_RELEASE_ASSERT(Task2(true, 3).unwrap() == 3);
@@ -87,6 +171,12 @@ static void BasicTests() {
   MOZ_RELEASE_ASSERT(Task2(false, 3).isErr());
   MOZ_RELEASE_ASSERT(Task2(false, 3).unwrapOr(6) == 6);
 
+  MOZ_RELEASE_ASSERT(Task2UnusedZeroEnumErr(true, 3).isOk());
+  MOZ_RELEASE_ASSERT(Task2UnusedZeroEnumErr(true, 3).unwrap() == 3);
+  MOZ_RELEASE_ASSERT(Task2UnusedZeroEnumErr(true, 3).unwrapOr(6) == 3);
+  MOZ_RELEASE_ASSERT(Task2UnusedZeroEnumErr(false, 3).isErr());
+  MOZ_RELEASE_ASSERT(Task2UnusedZeroEnumErr(false, 3).unwrapOr(6) == 6);
+
   // MOZ_TRY_VAR works.
   MOZ_RELEASE_ASSERT(Task3(true, true, 3).isOk());
   MOZ_RELEASE_ASSERT(Task3(true, true, 3).unwrap() == 6);
@@ -96,7 +186,7 @@ static void BasicTests() {
 
   // Lvalues should work too.
   {
-    Result<Ok, Failed&> res = Task1(true);
+    Result<Ok, Failed> res = Task1(true);
     MOZ_RELEASE_ASSERT(res.isOk());
     MOZ_RELEASE_ASSERT(!res.isErr());
 
@@ -106,7 +196,7 @@ static void BasicTests() {
   }
 
   {
-    Result<int, Failed&> res = Task2(true, 3);
+    Result<int, Failed> res = Task2(true, 3);
     MOZ_RELEASE_ASSERT(res.isOk());
     MOZ_RELEASE_ASSERT(res.unwrap() == 3);
 
@@ -117,19 +207,16 @@ static void BasicTests() {
   // Some tests for pointer tagging.
   {
     int i = 123;
-    double d = 3.14;
 
-    Result<int*, double&> res = &i;
+    Result<int*, Failed> res = &i;
     static_assert(sizeof(res) == sizeof(uintptr_t),
                   "should use pointer tagging to fit in a word");
 
     MOZ_RELEASE_ASSERT(res.isOk());
     MOZ_RELEASE_ASSERT(*res.unwrap() == 123);
 
-    res = Err(d);
+    res = Err(Failed());
     MOZ_RELEASE_ASSERT(res.isErr());
-    MOZ_RELEASE_ASSERT(&res.unwrapErr() == &d);
-    MOZ_RELEASE_ASSERT(res.unwrapErr() == 3.14);
   }
 }
 
@@ -153,22 +240,13 @@ static void TypeConversionTests() {
 
 static void EmptyValueTest() {
   struct Fine {};
-  mozilla::Result<Fine, int&> res((Fine()));
+  mozilla::Result<Fine, Failed> res((Fine()));
   res.unwrap();
   MOZ_RELEASE_ASSERT(res.isOk());
   static_assert(sizeof(res) == sizeof(uintptr_t),
                 "Result with empty value type should be pointer-sized");
 }
 
-static void ReferenceTest() {
-  struct MyError {
-    int x = 0;
-  };
-  MyError merror;
-  Result<int, MyError&> res(merror);
-  MOZ_RELEASE_ASSERT(&res.unwrapErr() == &merror);
-}
-
 static void MapTest() {
   struct MyError {
     int x;
@@ -176,34 +254,238 @@ static void MapTest() {
     explicit MyError(int y) : x(y) {}
   };
 
-  // Mapping over success values.
-  Result<int, MyError> res(5);
-  bool invoked = false;
-  auto res2 = res.map([&invoked](int x) {
-    MOZ_RELEASE_ASSERT(x == 5);
-    invoked = true;
-    return "hello";
-  });
-  MOZ_RELEASE_ASSERT(res2.isOk());
-  MOZ_RELEASE_ASSERT(invoked);
-  MOZ_RELEASE_ASSERT(strcmp(res2.unwrap(), "hello") == 0);
+  // Mapping over success values, to the same success type.
+  {
+    Result<int, MyError> res(5);
+    bool invoked = false;
+    auto res2 = res.map([&invoked](int x) {
+      MOZ_RELEASE_ASSERT(x == 5);
+      invoked = true;
+      return 6;
+    });
+    MOZ_RELEASE_ASSERT(res2.isOk());
+    MOZ_RELEASE_ASSERT(invoked);
+    MOZ_RELEASE_ASSERT(res2.unwrap() == 6);
+  }
+
+  // Mapping over success values, to a different success type.
+  {
+    Result<int, MyError> res(5);
+    bool invoked = false;
+    auto res2 = res.map([&invoked](int x) {
+      MOZ_RELEASE_ASSERT(x == 5);
+      invoked = true;
+      return "hello";
+    });
+    MOZ_RELEASE_ASSERT(res2.isOk());
+    MOZ_RELEASE_ASSERT(invoked);
+    MOZ_RELEASE_ASSERT(strcmp(res2.unwrap(), "hello") == 0);
+  }
 
   // Mapping over error values.
-  MyError err(1);
-  Result<char, MyError> res3(err);
-  MOZ_RELEASE_ASSERT(res3.isErr());
-  Result<char, MyError> res4 = res3.map([](int x) {
-    MOZ_RELEASE_ASSERT(false);
-    return 'a';
-  });
-  MOZ_RELEASE_ASSERT(res4.isErr());
-  MOZ_RELEASE_ASSERT(res4.unwrapErr().x == err.x);
+  {
+    MyError err(1);
+    Result<char, MyError> res(err);
+    MOZ_RELEASE_ASSERT(res.isErr());
+    Result<char, MyError> res2 = res.map([](int x) {
+      MOZ_RELEASE_ASSERT(false);
+      return 'a';
+    });
+    MOZ_RELEASE_ASSERT(res2.isErr());
+    MOZ_RELEASE_ASSERT(res2.unwrapErr().x == err.x);
+  }
 
-  // Function pointers instead of lamdbas as the mapping function.
-  Result<const char*, MyError> res5("hello");
-  auto res6 = res5.map(strlen);
-  MOZ_RELEASE_ASSERT(res6.isOk());
-  MOZ_RELEASE_ASSERT(res6.unwrap() == 5);
+  // Function pointers instead of lambdas as the mapping function.
+  {
+    Result<const char*, MyError> res("hello");
+    auto res2 = res.map(strlen);
+    MOZ_RELEASE_ASSERT(res2.isOk());
+    MOZ_RELEASE_ASSERT(res2.unwrap() == 5);
+  }
+}
+
+static void MapErrTest() {
+  struct MyError {
+    int x;
+
+    explicit MyError(int y) : x(y) {}
+  };
+
+  struct MyError2 {
+    int a;
+
+    explicit MyError2(int b) : a(b) {}
+  };
+
+  // Mapping over error values, to the same error type.
+  {
+    MyError err(1);
+    Result<char, MyError> res(err);
+    MOZ_RELEASE_ASSERT(res.isErr());
+    bool invoked = false;
+    auto res2 = res.mapErr([&invoked](const auto err) {
+      MOZ_RELEASE_ASSERT(err.x == 1);
+      invoked = true;
+      return MyError(2);
+    });
+    MOZ_RELEASE_ASSERT(res2.isErr());
+    MOZ_RELEASE_ASSERT(invoked);
+    MOZ_RELEASE_ASSERT(res2.unwrapErr().x == 2);
+  }
+
+  // Mapping over error values, to a different error type.
+  {
+    MyError err(1);
+    Result<char, MyError> res(err);
+    MOZ_RELEASE_ASSERT(res.isErr());
+    bool invoked = false;
+    auto res2 = res.mapErr([&invoked](const auto err) {
+      MOZ_RELEASE_ASSERT(err.x == 1);
+      invoked = true;
+      return MyError2(2);
+    });
+    MOZ_RELEASE_ASSERT(res2.isErr());
+    MOZ_RELEASE_ASSERT(invoked);
+    MOZ_RELEASE_ASSERT(res2.unwrapErr().a == 2);
+  }
+
+  // Mapping over success values.
+  {
+    Result<int, MyError> res(5);
+    auto res2 = res.mapErr([](const auto err) {
+      MOZ_RELEASE_ASSERT(false);
+      return MyError(1);
+    });
+    MOZ_RELEASE_ASSERT(res2.isOk());
+    MOZ_RELEASE_ASSERT(res2.unwrap() == 5);
+  }
+
+  // Function pointers instead of lambdas as the mapping function.
+  {
+    Result<Ok, const char*> res("hello");
+    auto res2 = res.mapErr(strlen);
+    MOZ_RELEASE_ASSERT(res2.isErr());
+    MOZ_RELEASE_ASSERT(res2.unwrapErr() == 5);
+  }
+}
+
+static Result<Ok, size_t> strlen_ResultWrapper(const char* aValue) {
+  return Err(strlen(aValue));
+}
+
+static void OrElseTest() {
+  struct MyError {
+    int x;
+
+    explicit MyError(int y) : x(y) {}
+  };
+
+  struct MyError2 {
+    int a;
+
+    explicit MyError2(int b) : a(b) {}
+  };
+
+  // `orElse`ing over error values, to Result<V, E> (the same error type) error
+  // variant.
+  {
+    MyError err(1);
+    Result<char, MyError> res(err);
+    MOZ_RELEASE_ASSERT(res.isErr());
+    bool invoked = false;
+    auto res2 = res.orElse([&invoked](const auto err) -> Result<char, MyError> {
+      MOZ_RELEASE_ASSERT(err.x == 1);
+      invoked = true;
+      if (err.x != 42) {
+        return Err(MyError(2));
+      }
+      return 'a';
+    });
+    MOZ_RELEASE_ASSERT(res2.isErr());
+    MOZ_RELEASE_ASSERT(invoked);
+    MOZ_RELEASE_ASSERT(res2.unwrapErr().x == 2);
+  }
+
+  // `orElse`ing over error values, to Result<V, E> (the same error type)
+  // success variant.
+  {
+    MyError err(42);
+    Result<char, MyError> res(err);
+    MOZ_RELEASE_ASSERT(res.isErr());
+    bool invoked = false;
+    auto res2 = res.orElse([&invoked](const auto err) -> Result<char, MyError> {
+      MOZ_RELEASE_ASSERT(err.x == 42);
+      invoked = true;
+      if (err.x != 42) {
+        return Err(MyError(2));
+      }
+      return 'a';
+    });
+    MOZ_RELEASE_ASSERT(res2.isOk());
+    MOZ_RELEASE_ASSERT(invoked);
+    MOZ_RELEASE_ASSERT(res2.unwrap() == 'a');
+  }
+
+  // `orElse`ing over error values, to Result<V, E2> (a different error type)
+  // error variant.
+  {
+    MyError err(1);
+    Result<char, MyError> res(err);
+    MOZ_RELEASE_ASSERT(res.isErr());
+    bool invoked = false;
+    auto res2 =
+        res.orElse([&invoked](const auto err) -> Result<char, MyError2> {
+          MOZ_RELEASE_ASSERT(err.x == 1);
+          invoked = true;
+          if (err.x != 42) {
+            return Err(MyError2(2));
+          }
+          return 'a';
+        });
+    MOZ_RELEASE_ASSERT(res2.isErr());
+    MOZ_RELEASE_ASSERT(invoked);
+    MOZ_RELEASE_ASSERT(res2.unwrapErr().a == 2);
+  }
+
+  // `orElse`ing over error values, to Result<V, E2> (a different error type)
+  // success variant.
+  {
+    MyError err(42);
+    Result<char, MyError> res(err);
+    MOZ_RELEASE_ASSERT(res.isErr());
+    bool invoked = false;
+    auto res2 =
+        res.orElse([&invoked](const auto err) -> Result<char, MyError2> {
+          MOZ_RELEASE_ASSERT(err.x == 42);
+          invoked = true;
+          if (err.x != 42) {
+            return Err(MyError2(2));
+          }
+          return 'a';
+        });
+    MOZ_RELEASE_ASSERT(res2.isOk());
+    MOZ_RELEASE_ASSERT(invoked);
+    MOZ_RELEASE_ASSERT(res2.unwrap() == 'a');
+  }
+
+  // `orElse`ing over success values.
+  {
+    Result<int, MyError> res(5);
+    auto res2 = res.orElse([](const auto err) -> Result<int, MyError> {
+      MOZ_RELEASE_ASSERT(false);
+      return Err(MyError(1));
+    });
+    MOZ_RELEASE_ASSERT(res2.isOk());
+    MOZ_RELEASE_ASSERT(res2.unwrap() == 5);
+  }
+
+  // Function pointers instead of lambdas as the `orElse`ing function.
+  {
+    Result<Ok, const char*> res("hello");
+    auto res2 = res.orElse(strlen_ResultWrapper);
+    MOZ_RELEASE_ASSERT(res2.isErr());
+    MOZ_RELEASE_ASSERT(res2.unwrapErr() == 5);
+  }
 }
 
 static void AndThenTest() {
@@ -294,8 +576,9 @@ int main() {
   BasicTests();
   TypeConversionTests();
   EmptyValueTest();
-  ReferenceTest();
   MapTest();
+  MapErrTest();
+  OrElseTest();
   AndThenTest();
   UniquePtrTest();
   return 0;
diff --git a/mfbt/tests/TestScopeExit.cpp b/mfbt/tests/TestScopeExit.cpp
index 383bc48bda..7b46dd9a58 100644
--- a/mfbt/tests/TestScopeExit.cpp
+++ b/mfbt/tests/TestScopeExit.cpp
@@ -19,6 +19,7 @@ using mozilla::MakeScopeExit;
 static bool Test() {
   int a = 1;
   int b = 1;
+  int c = 1;
 
   {
     a++;
@@ -28,10 +29,18 @@ static bool Test() {
     auto guardB = MakeScopeExit([&] { b--; });
 
     guardB.release();
+
+    c++;
+    auto guardC = MakeScopeExit([&] { c--; });
+
+    { auto guardC_ = std::move(guardC); }
+
+    CHECK(c == 1);
   }
 
   CHECK(a == 1);
   CHECK(b == 2);
+  CHECK(c == 1);
 
   return true;
 }
diff --git a/mfbt/tests/TestTuple.cpp b/mfbt/tests/TestTuple.cpp
index 6bd6090da9..5beece2378 100644
--- a/mfbt/tests/TestTuple.cpp
+++ b/mfbt/tests/TestTuple.cpp
@@ -2,22 +2,22 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
  * You can obtain one at http://mozilla.org/MPL/2.0/. */
 
+#include <stddef.h>
+
+#include <utility>
+
 #include "mozilla/Assertions.h"
-#include "mozilla/Move.h"
-#include "mozilla/Pair.h"
+#include "mozilla/CompactPair.h"
 #include "mozilla/Tuple.h"
 #include "mozilla/TypeTraits.h"
 #include "mozilla/UniquePtr.h"
 #include "mozilla/Unused.h"
 
-#include <stddef.h>
-#include <utility>
-
+using mozilla::CompactPair;
 using mozilla::Get;
 using mozilla::IsSame;
 using mozilla::MakeTuple;
 using mozilla::MakeUnique;
-using mozilla::Pair;
 using mozilla::Tie;
 using mozilla::Tuple;
 using mozilla::UniquePtr;
@@ -79,8 +79,8 @@ static void TestConstruction() {
 static void TestConstructionFromMozPair() {
   // Construction from elements
   int x = 1, y = 1;
-  Pair<int, int> a{x, y};
-  Pair<int&, const int&> b{x, y};
+  CompactPair<int, int> a{x, y};
+  CompactPair<int&, const int&> b{x, y};
   Tuple<int, int> c(a);
   Tuple<int&, const int&> d(b);
   x = 42;
@@ -132,7 +132,7 @@ static void TestAssignment() {
 static void TestAssignmentFromMozPair() {
   // Copy assignment
   Tuple<int, int> a{0, 0};
-  Pair<int, int> b{42, 42};
+  CompactPair<int, int> b{42, 42};
   a = b;
   CHECK(Get<0>(a) == 42);
   CHECK(Get<1>(a) == 42);
@@ -142,7 +142,7 @@ static void TestAssignmentFromMozPair() {
   int j = 0;
   int k = 42;
   Tuple<int&, int&> c{i, j};
-  Pair<int&, int&> d{k, k};
+  CompactPair<int&, int&> d{k, k};
   c = d;
   CHECK(i == 42);
   CHECK(j == 42);
@@ -150,8 +150,8 @@ static void TestAssignmentFromMozPair() {
   // Move assignment
   Tuple<UniquePtr<int>, UniquePtr<int>> e{MakeUnique<int>(0),
                                           MakeUnique<int>(0)};
-  Pair<UniquePtr<int>, UniquePtr<int>> f{MakeUnique<int>(42),
-                                         MakeUnique<int>(42)};
+  CompactPair<UniquePtr<int>, UniquePtr<int>> f{MakeUnique<int>(42),
+                                                MakeUnique<int>(42)};
   e = std::move(f);
   CHECK(*Get<0>(e) == 42);
   CHECK(*Get<1>(e) == 42);
@@ -228,6 +228,32 @@ static void TestMakeTuple() {
   CHECK(Get<0>(tuple2) == 1);
 }
 
+static bool TestTieMozPair() {
+  int i;
+  float f;
+  char c;
+  Tuple<int, float, char> rhs1(42, 0.5f, 'c');
+  Tie(i, f, c) = rhs1;
+  CHECK(i == Get<0>(rhs1));
+  CHECK(f == Get<1>(rhs1));
+  CHECK(c == Get<2>(rhs1));
+  // Test conversions
+  Tuple<ConvertibleToInt, double, unsigned char> rhs2(ConvertibleToInt(), 0.7f,
+                                                      'd');
+  Tie(i, f, c) = rhs2;
+  CHECK(i == Get<0>(rhs2));
+  CHECK(f == Get<1>(rhs2));
+  CHECK(c == Get<2>(rhs2));
+
+  // Test Pair
+  CompactPair<int, float> rhs3(42, 1.5f);
+  Tie(i, f) = rhs3;
+  CHECK(i == rhs3.first());
+  CHECK(f == rhs3.second());
+
+  return true;
+}
+
 static bool TestTie() {
   int i;
   float f;
@@ -246,15 +272,23 @@ static bool TestTie() {
   CHECK(c == Get<2>(rhs2));
 
   // Test Pair
-  Pair<int, float> rhs3(-1, 1.2f);
+  pair<int, float> rhs3(42, 1.5f);
   Tie(i, f) = rhs3;
-  CHECK(i == rhs3.first());
-  CHECK(f == rhs3.second());
+  CHECK(i == rhs3.first);
+  CHECK(f == rhs3.second);
 
-  pair<int, float> rhs4(42, 1.5f);
-  Tie(i, f) = rhs4;
-  CHECK(i == rhs4.first);
-  CHECK(f == rhs4.second);
+  return true;
+}
+
+static bool TestTieIgnore() {
+  int i;
+  char c;
+  Tuple<int, float, char> rhs1(42, 0.5f, 'c');
+
+  Tie(i, mozilla::Ignore, c) = rhs1;
+
+  CHECK(i == Get<0>(rhs1));
+  CHECK(c == Get<2>(rhs1));
 
   return true;
 }
@@ -269,5 +303,7 @@ int main() {
   TestGet();
   TestMakeTuple();
   TestTie();
+  TestTieIgnore();
+  TestTieMozPair();
   return 0;
 }
diff --git a/mfbt/tests/TestTypeTraits.cpp b/mfbt/tests/TestTypeTraits.cpp
index 4fae1e0b7c..cf2dc0fca5 100644
--- a/mfbt/tests/TestTypeTraits.cpp
+++ b/mfbt/tests/TestTypeTraits.cpp
@@ -6,16 +6,8 @@
 #include "mozilla/TypeTraits.h"
 
 using mozilla::AddRvalueReference;
-using mozilla::DeclVal;
-using mozilla::IsArray;
-using mozilla::IsConvertible;
 using mozilla::IsDestructible;
 using mozilla::IsSame;
-using mozilla::RemovePointer;
-
-static_assert(!IsArray<bool>::value, "bool not an array");
-static_assert(IsArray<bool[]>::value, "bool[] is an array");
-static_assert(IsArray<bool[5]>::value, "bool[5] is an array");
 
 class PublicDestructible {
  public:
@@ -34,50 +26,6 @@ static_assert(!IsDestructible<PrivateDestructible>::value,
 static_assert(IsDestructible<TrivialDestructible>::value,
               "trivial destructible class is destructible");
 
-class A {};
-class B : public A {};
-class C : private A {};
-class D {};
-class E : public A {};
-class F : public B, public E {};
-
-class ExplicitCopyConstructor {
-  explicit ExplicitCopyConstructor(const ExplicitCopyConstructor&) = default;
-};
-
-static void TestIsConvertible() {
-  // Pointer type convertibility
-  static_assert((IsConvertible<A*, A*>::value), "A* should convert to A*");
-  static_assert((IsConvertible<B*, A*>::value), "B* should convert to A*");
-  static_assert((!IsConvertible<A*, B*>::value), "A* shouldn't convert to B*");
-  static_assert((!IsConvertible<A*, C*>::value), "A* shouldn't convert to C*");
-  static_assert((!IsConvertible<A*, D*>::value),
-                "A* shouldn't convert to unrelated D*");
-  static_assert((!IsConvertible<D*, A*>::value),
-                "D* shouldn't convert to unrelated A*");
-
-  // Instance type convertibility
-  static_assert((IsConvertible<A, A>::value), "A is A");
-  static_assert((IsConvertible<B, A>::value), "B converts to A");
-  static_assert((!IsConvertible<D, A>::value), "D and A are unrelated");
-  static_assert((!IsConvertible<A, D>::value), "A and D are unrelated");
-
-  static_assert(IsConvertible<void, void>::value, "void is void");
-  static_assert(!IsConvertible<A, void>::value, "A shouldn't convert to void");
-  static_assert(!IsConvertible<void, B>::value, "void shouldn't convert to B");
-
-  static_assert(!IsConvertible<const ExplicitCopyConstructor&,
-                               ExplicitCopyConstructor>::value,
-                "IsConvertible should test for implicit convertibility");
-
-  // These cases seem to require C++11 support to properly implement them, so
-  // for now just disable them.
-  // static_assert((!IsConvertible<C*, A*>::value),
-  //           "C* shouldn't convert to A* (private inheritance)");
-  // static_assert((!IsConvertible<C, A>::value),
-  //           "C doesn't convert to A (private inheritance)");
-}
-
 static_assert(IsSame<AddRvalueReference<int>::Type, int&&>::value,
               "not adding && to int correctly");
 static_assert(
@@ -92,49 +40,6 @@ static_assert(IsSame<AddRvalueReference<void>::Type, void>::value,
 static_assert(IsSame<AddRvalueReference<struct S1&>::Type, struct S1&>::value,
               "not reference-collapsing struct S1& && to struct S1& correctly");
 
-struct TestWithDefaultConstructor {
-  int foo() const { return 0; }
-};
-struct TestWithNoDefaultConstructor {
-  explicit TestWithNoDefaultConstructor(int) {}
-  int foo() const { return 1; }
-};
-
-static_assert(IsSame<decltype(TestWithDefaultConstructor().foo()), int>::value,
-              "decltype should work using a struct with a default constructor");
-static_assert(
-    IsSame<decltype(DeclVal<TestWithDefaultConstructor>().foo()), int>::value,
-    "decltype should work using a DeclVal'd struct with a default constructor");
-static_assert(
-    IsSame<decltype(DeclVal<TestWithNoDefaultConstructor>().foo()), int>::value,
-    "decltype should work using a DeclVal'd struct without a default "
-    "constructor");
-
-struct TestRemovePointer {
-  bool m;
-  void f();
-};
-static_assert(IsSame<RemovePointer<int>::Type, int>::value,
-              "removing pointer from int must return int");
-static_assert(IsSame<RemovePointer<int*>::Type, int>::value,
-              "removing pointer from int* must return int");
-static_assert(IsSame<RemovePointer<int* const>::Type, int>::value,
-              "removing pointer from int* const must return int");
-static_assert(IsSame<RemovePointer<int* volatile>::Type, int>::value,
-              "removing pointer from int* volatile must return int");
-static_assert(IsSame<RemovePointer<const long*>::Type, const long>::value,
-              "removing pointer from const long* must return const long");
-static_assert(IsSame<RemovePointer<void* const>::Type, void>::value,
-              "removing pointer from void* const must return void");
-static_assert(IsSame<RemovePointer<void (TestRemovePointer::*)()>::Type,
-                     void (TestRemovePointer::*)()>::value,
-              "removing pointer from void (S::*)() must return void (S::*)()");
-static_assert(IsSame<RemovePointer<void (*)()>::Type, void()>::value,
-              "removing pointer from void (*)() must return void()");
-static_assert(IsSame<RemovePointer<bool TestRemovePointer::*>::Type,
-                     bool TestRemovePointer::*>::value,
-              "removing pointer from bool S::* must return bool S::*");
-
 /*
  * Android's broken [u]intptr_t inttype macros are broken because its PRI*PTR
  * macros are defined as "ld", but sizeof(long) is 8 and sizeof(intptr_t)
@@ -149,7 +54,4 @@ static_assert(mozilla::IsSame<unsigned int, uintptr_t>::value,
               "emulated PRI[ouxX]PTR definitions will be wrong");
 #endif
 
-int main() {
-  TestIsConvertible();
-  return 0;
-}
+int main() { return 0; }
diff --git a/mfbt/tests/TestTypedEnum.cpp b/mfbt/tests/TestTypedEnum.cpp
index 7a21514216..7669d7fd37 100644
--- a/mfbt/tests/TestTypedEnum.cpp
+++ b/mfbt/tests/TestTypedEnum.cpp
@@ -7,6 +7,7 @@
 #include "mozilla/TypedEnumBits.h"
 
 #include <stdint.h>
+#include <type_traits>
 
 // A rough feature check for is_literal_type. Not very carefully checked.
 // Feel free to amend as needed.
@@ -109,16 +110,14 @@ MAKE_STANDARD_BITFIELD_FOR_TYPE(unsigned_long_long)
 
 template <typename T>
 void TestNonConvertibilityForOneType() {
-  using mozilla::IsConvertible;
-
-  static_assert(!IsConvertible<T, bool>::value, "should not be convertible");
-  static_assert(!IsConvertible<T, int>::value, "should not be convertible");
-  static_assert(!IsConvertible<T, uint64_t>::value,
+  static_assert(!std::is_convertible_v<T, bool>, "should not be convertible");
+  static_assert(!std::is_convertible_v<T, int>, "should not be convertible");
+  static_assert(!std::is_convertible_v<T, uint64_t>,
                 "should not be convertible");
 
-  static_assert(!IsConvertible<bool, T>::value, "should not be convertible");
-  static_assert(!IsConvertible<int, T>::value, "should not be convertible");
-  static_assert(!IsConvertible<uint64_t, T>::value,
+  static_assert(!std::is_convertible_v<bool, T>, "should not be convertible");
+  static_assert(!std::is_convertible_v<int, T>, "should not be convertible");
+  static_assert(!std::is_convertible_v<uint64_t, T>,
                 "should not be convertible");
 }
 
@@ -369,32 +368,32 @@ void TestTypedEnumBitField() {
 // properties as c++11 enum classes do, i.e. not implicitly convertible to
 // anything (though *explicitly* convertible).
 void TestNoConversionsBetweenUnrelatedTypes() {
-  using mozilla::IsConvertible;
-
   // Two typed enum classes having the same underlying integer type, to ensure
   // that we would catch bugs accidentally allowing conversions in that case.
   typedef CharEnumBitField T1;
   typedef Nested::CharEnumBitField T2;
 
-  static_assert(!IsConvertible<T1, T2>::value, "should not be convertible");
-  static_assert(!IsConvertible<T1, decltype(T2::A)>::value,
+  static_assert(!std::is_convertible_v<T1, T2>, "should not be convertible");
+  static_assert(!std::is_convertible_v<T1, decltype(T2::A)>,
                 "should not be convertible");
-  static_assert(!IsConvertible<T1, decltype(T2::A | T2::B)>::value,
+  static_assert(!std::is_convertible_v<T1, decltype(T2::A | T2::B)>,
                 "should not be convertible");
 
-  static_assert(!IsConvertible<decltype(T1::A), T2>::value,
+  static_assert(!std::is_convertible_v<decltype(T1::A), T2>,
                 "should not be convertible");
-  static_assert(!IsConvertible<decltype(T1::A), decltype(T2::A)>::value,
-                "should not be convertible");
-  static_assert(!IsConvertible<decltype(T1::A), decltype(T2::A | T2::B)>::value,
-                "should not be convertible");
-
-  static_assert(!IsConvertible<decltype(T1::A | T1::B), T2>::value,
-                "should not be convertible");
-  static_assert(!IsConvertible<decltype(T1::A | T1::B), decltype(T2::A)>::value,
+  static_assert(!std::is_convertible_v<decltype(T1::A), decltype(T2::A)>,
                 "should not be convertible");
   static_assert(
-      !IsConvertible<decltype(T1::A | T1::B), decltype(T2::A | T2::B)>::value,
+      !std::is_convertible_v<decltype(T1::A), decltype(T2::A | T2::B)>,
+      "should not be convertible");
+
+  static_assert(!std::is_convertible_v<decltype(T1::A | T1::B), T2>,
+                "should not be convertible");
+  static_assert(
+      !std::is_convertible_v<decltype(T1::A | T1::B), decltype(T2::A)>,
+      "should not be convertible");
+  static_assert(
+      !std::is_convertible_v<decltype(T1::A | T1::B), decltype(T2::A | T2::B)>,
       "should not be convertible");
 }
 
diff --git a/mfbt/tests/TestUniquePtr.cpp b/mfbt/tests/TestUniquePtr.cpp
index 58e2c97b8c..4de73192be 100644
--- a/mfbt/tests/TestUniquePtr.cpp
+++ b/mfbt/tests/TestUniquePtr.cpp
@@ -2,20 +2,20 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
  * You can obtain one at http://mozilla.org/MPL/2.0/. */
 
+#include <stddef.h>
+
+#include <utility>
+
 #include "mozilla/Assertions.h"
 #include "mozilla/Compiler.h"
-#include "mozilla/Move.h"
 #include "mozilla/TypeTraits.h"
 #include "mozilla/UniquePtr.h"
 #include "mozilla/UniquePtrExtensions.h"
 #include "mozilla/Vector.h"
 
-#include <stddef.h>
-
 using mozilla::DefaultDelete;
 using mozilla::IsSame;
 using mozilla::MakeUnique;
-using mozilla::Swap;
 using mozilla::UniqueFreePtr;
 using mozilla::UniquePtr;
 using mozilla::Vector;
@@ -101,7 +101,7 @@ static bool TestDefaultFreeGuts() {
   CHECK(n1.get() == nullptr);
   CHECK(n2.get() == p1);
 
-  Swap(n1, n2);
+  std::swap(n1, n2);
   CHECK(n1.get() == p1);
   CHECK(n2.get() == nullptr);
 
@@ -436,7 +436,7 @@ static bool TestArray() {
   CHECK(n1.get() == nullptr);
   CHECK(n2.get() == p1);
 
-  Swap(n1, n2);
+  std::swap(n1, n2);
   CHECK(n1.get() == p1);
   CHECK(n2.get() == nullptr);
 
diff --git a/mfbt/tests/TestVector.cpp b/mfbt/tests/TestVector.cpp
index 653fd84c0a..b0fcbf2054 100644
--- a/mfbt/tests/TestVector.cpp
+++ b/mfbt/tests/TestVector.cpp
@@ -2,7 +2,8 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
  * You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-#include "mozilla/Move.h"
+#include <utility>
+
 #include "mozilla/UniquePtr.h"
 #include "mozilla/Vector.h"
 
diff --git a/mfbt/tests/gtest/TestAlgorithm.cpp b/mfbt/tests/gtest/TestAlgorithm.cpp
new file mode 100644
index 0000000000..b54e9ad8a0
--- /dev/null
+++ b/mfbt/tests/gtest/TestAlgorithm.cpp
@@ -0,0 +1,189 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "gtest/gtest.h"
+
+#include "mozilla/Algorithm.h"
+#include "mozilla/Maybe.h"
+#include "mozilla/Result.h"
+
+#include <iterator>
+#include <vector>
+
+using namespace mozilla;
+using std::begin;
+using std::end;
+
+namespace {
+struct MoveOnly {
+  explicit MoveOnly(int32_t aValue) : mValue{Some(aValue)} {}
+
+  MoveOnly(MoveOnly&&) = default;
+  MoveOnly& operator=(MoveOnly&&) = default;
+
+  Maybe<int32_t> mValue;
+};
+
+struct TestError {};
+
+constexpr static int32_t arr1[3] = {1, 2, 3};
+}  // namespace
+
+TEST(MFBT_Algorithm_TransformAbortOnErr, NoError)
+{
+  std::vector<int64_t> out;
+  auto res = TransformAbortOnErr(
+      begin(arr1), end(arr1), std::back_inserter(out),
+      [](const int32_t value) -> Result<int64_t, TestError> {
+        return value * 10;
+      });
+  ASSERT_TRUE(res.isOk());
+
+  const std::vector<int64_t> expected = {10, 20, 30};
+  ASSERT_EQ(expected, out);
+}
+
+TEST(MFBT_Algorithm_TransformAbortOnErr, NoError_Range)
+{
+  std::vector<int64_t> out;
+  auto res = TransformAbortOnErr(
+      arr1, std::back_inserter(out),
+      [](const int32_t value) -> Result<int64_t, TestError> {
+        return value * 10;
+      });
+  ASSERT_TRUE(res.isOk());
+
+  const std::vector<int64_t> expected = {10, 20, 30};
+  ASSERT_EQ(expected, out);
+}
+
+TEST(MFBT_Algorithm_TransformAbortOnErr, ErrorOnFirst)
+{
+  std::vector<int64_t> out;
+  auto res = TransformAbortOnErr(
+      begin(arr1), end(arr1), std::back_inserter(out),
+      [](const int32_t value) -> Result<int64_t, TestError> {
+        return Err(TestError{});
+      });
+  ASSERT_TRUE(res.isErr());
+  ASSERT_TRUE(out.empty());
+}
+
+TEST(MFBT_Algorithm_TransformAbortOnErr, ErrorOnOther)
+{
+  std::vector<int64_t> out;
+  auto res = TransformAbortOnErr(
+      begin(arr1), end(arr1), std::back_inserter(out),
+      [](const int32_t value) -> Result<int64_t, TestError> {
+        if (value > 2) {
+          return Err(TestError{});
+        }
+        return value * 10;
+      });
+  ASSERT_TRUE(res.isErr());
+
+  // XXX Should we assert on this, or is the content of out an implementation
+  // detail?
+  const std::vector<int64_t> expected = {10, 20};
+  ASSERT_EQ(expected, out);
+}
+
+TEST(MFBT_Algorithm_TransformAbortOnErr, ErrorOnOther_Move)
+{
+  MoveOnly in[3] = {MoveOnly{1}, MoveOnly{2}, MoveOnly{3}};
+  std::vector<int64_t> out;
+  auto res = TransformAbortOnErr(
+      std::make_move_iterator(begin(in)), std::make_move_iterator(end(in)),
+      std::back_inserter(out),
+      [](MoveOnly value) -> Result<int64_t, TestError> {
+        if (*value.mValue > 1) {
+          return Err(TestError{});
+        }
+        return *value.mValue * 10;
+      });
+  ASSERT_TRUE(res.isErr());
+
+  ASSERT_FALSE(in[0].mValue);
+  ASSERT_FALSE(in[1].mValue);
+  ASSERT_TRUE(in[2].mValue);
+
+  // XXX Should we assert on this, or is the content of out an implementation
+  // detail?
+  const std::vector<int64_t> expected = {10};
+  ASSERT_EQ(expected, out);
+}
+
+TEST(MFBT_Algorithm_TransformIfAbortOnErr, NoError)
+{
+  std::vector<int64_t> out;
+  auto res = TransformIfAbortOnErr(
+      begin(arr1), end(arr1), std::back_inserter(out),
+      [](const int32_t value) { return value % 2 == 1; },
+      [](const int32_t value) -> Result<int64_t, TestError> {
+        return value * 10;
+      });
+  ASSERT_TRUE(res.isOk());
+
+  const std::vector<int64_t> expected = {10, 30};
+  ASSERT_EQ(expected, out);
+}
+
+TEST(MFBT_Algorithm_TransformIfAbortOnErr, NoError_Range)
+{
+  std::vector<int64_t> out;
+  auto res = TransformIfAbortOnErr(
+      arr1, std::back_inserter(out),
+      [](const int32_t value) { return value % 2 == 1; },
+      [](const int32_t value) -> Result<int64_t, TestError> {
+        return value * 10;
+      });
+  ASSERT_TRUE(res.isOk());
+
+  const std::vector<int64_t> expected = {10, 30};
+  ASSERT_EQ(expected, out);
+}
+
+TEST(MFBT_Algorithm_TransformIfAbortOnErr, ErrorOnOther)
+{
+  std::vector<int64_t> out;
+  auto res = TransformIfAbortOnErr(
+      begin(arr1), end(arr1), std::back_inserter(out),
+      [](const int32_t value) { return value % 2 == 1; },
+      [](const int32_t value) -> Result<int64_t, TestError> {
+        if (value > 2) {
+          return Err(TestError{});
+        }
+        return value * 10;
+      });
+  ASSERT_TRUE(res.isErr());
+
+  const std::vector<int64_t> expected = {10};
+  ASSERT_EQ(expected, out);
+}
+
+TEST(MFBT_Algorithm_TransformIfAbortOnErr, ErrorOnOther_Move)
+{
+  MoveOnly in[3] = {MoveOnly{1}, MoveOnly{2}, MoveOnly{3}};
+  std::vector<int64_t> out;
+  auto res = TransformIfAbortOnErr(
+      std::make_move_iterator(begin(in)), std::make_move_iterator(end(in)),
+      std::back_inserter(out),
+      [](const MoveOnly& value) { return *value.mValue % 2 == 1; },
+      [](MoveOnly value) -> Result<int64_t, TestError> {
+        if (*value.mValue > 1) {
+          return Err(TestError{});
+        }
+        return *value.mValue * 10;
+      });
+  ASSERT_TRUE(res.isErr());
+
+  ASSERT_FALSE(in[0].mValue);
+  ASSERT_TRUE(in[1].mValue);
+  ASSERT_FALSE(in[2].mValue);
+
+  // XXX Should we assert on this, or is the content of out an implementation
+  // detail?
+  const std::vector<int64_t> expected = {10};
+  ASSERT_EQ(expected, out);
+}
diff --git a/mfbt/tests/gtest/TestResultExtensions.cpp b/mfbt/tests/gtest/TestResultExtensions.cpp
new file mode 100644
index 0000000000..00b753aaaf
--- /dev/null
+++ b/mfbt/tests/gtest/TestResultExtensions.cpp
@@ -0,0 +1,478 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "gtest/gtest.h"
+
+#include "mozilla/ResultExtensions.h"
+#include "nsLocalFile.h"
+
+#include <functional>
+
+using namespace mozilla;
+
+namespace {
+class TestClass {
+ public:
+  static constexpr int kTestValue = 42;
+
+  nsresult NonOverloadedNoInput(int* aOut) {
+    *aOut = kTestValue;
+    return NS_OK;
+  }
+  nsresult NonOverloadedNoInputFails(int* aOut) { return NS_ERROR_FAILURE; }
+
+  nsresult NonOverloadedNoInputConst(int* aOut) const {
+    *aOut = kTestValue;
+    return NS_OK;
+  }
+  nsresult NonOverloadedNoInputFailsConst(int* aOut) const {
+    return NS_ERROR_FAILURE;
+  }
+
+  nsresult NonOverloadedNoInputRef(int& aOut) {
+    aOut = kTestValue;
+    return NS_OK;
+  }
+  nsresult NonOverloadedNoInputFailsRef(int& aOut) { return NS_ERROR_FAILURE; }
+
+  nsresult NonOverloadedWithInput(int aIn, int* aOut) {
+    *aOut = aIn;
+    return NS_OK;
+  }
+  nsresult NonOverloadedWithInputFails(int aIn, int* aOut) {
+    return NS_ERROR_FAILURE;
+  }
+
+  nsresult NonOverloadedNoOutput(int aIn) { return NS_OK; }
+  nsresult NonOverloadedNoOutputFails(int aIn) { return NS_ERROR_FAILURE; }
+
+  nsresult PolymorphicNoInput(nsIFile** aOut) {
+    *aOut = MakeAndAddRef<nsLocalFile>().take();
+    return NS_OK;
+  }
+  nsresult PolymorphicNoInputFails(nsIFile** aOut) { return NS_ERROR_FAILURE; }
+};
+
+class RefCountedTestClass {
+ public:
+  NS_INLINE_DECL_REFCOUNTING(RefCountedTestClass);
+
+  static constexpr int kTestValue = 42;
+
+  nsresult NonOverloadedNoInput(int* aOut) {
+    *aOut = kTestValue;
+    return NS_OK;
+  }
+  nsresult NonOverloadedNoInputFails(int* aOut) { return NS_ERROR_FAILURE; }
+
+ private:
+  ~RefCountedTestClass() = default;
+};
+
+// Check that DerefedType deduces the types as expected
+static_assert(std::is_same_v<mozilla::detail::DerefedType<RefCountedTestClass&>,
+                             RefCountedTestClass>);
+static_assert(std::is_same_v<mozilla::detail::DerefedType<RefCountedTestClass*>,
+                             RefCountedTestClass>);
+static_assert(
+    std::is_same_v<mozilla::detail::DerefedType<RefPtr<RefCountedTestClass>>,
+                   RefCountedTestClass>);
+
+static_assert(std::is_same_v<mozilla::detail::DerefedType<nsIFile&>, nsIFile>);
+static_assert(std::is_same_v<mozilla::detail::DerefedType<nsIFile*>, nsIFile>);
+static_assert(
+    std::is_same_v<mozilla::detail::DerefedType<nsCOMPtr<nsIFile>>, nsIFile>);
+}  // namespace
+
+TEST(ResultExtensions_ToResultInvoke, Lambda)
+{
+  TestClass foo;
+
+  // success
+  {
+    auto valOrErr = ToResultInvoke<int>(
+        [&foo](int* out) { return foo.NonOverloadedNoInput(out); });
+    static_assert(std::is_same_v<decltype(valOrErr), Result<int, nsresult>>);
+    ASSERT_TRUE(valOrErr.isOk());
+    ASSERT_EQ(TestClass::kTestValue, valOrErr.unwrap());
+  }
+
+  // failure
+  {
+    auto valOrErr = ToResultInvoke<int>(
+        [&foo](int* out) { return foo.NonOverloadedNoInputFails(out); });
+    static_assert(std::is_same_v<decltype(valOrErr), Result<int, nsresult>>);
+    ASSERT_TRUE(valOrErr.isErr());
+    ASSERT_EQ(NS_ERROR_FAILURE, valOrErr.unwrapErr());
+  }
+}
+
+TEST(ResultExtensions_ToResultInvoke, MemFn)
+{
+  TestClass foo;
+
+  // success
+  {
+    auto valOrErr =
+        ToResultInvoke<int>(std::mem_fn(&TestClass::NonOverloadedNoInput), foo);
+    static_assert(std::is_same_v<decltype(valOrErr), Result<int, nsresult>>);
+    ASSERT_TRUE(valOrErr.isOk());
+    ASSERT_EQ(TestClass::kTestValue, valOrErr.unwrap());
+  }
+
+  // failure
+  {
+    auto valOrErr = ToResultInvoke<int>(
+        std::mem_fn(&TestClass::NonOverloadedNoInputFails), foo);
+    static_assert(std::is_same_v<decltype(valOrErr), Result<int, nsresult>>);
+    ASSERT_TRUE(valOrErr.isErr());
+    ASSERT_EQ(NS_ERROR_FAILURE, valOrErr.unwrapErr());
+  }
+}
+
+TEST(ResultExtensions_ToResultInvoke, MemberFunction_NoInput)
+{
+  TestClass foo;
+
+  // success
+  {
+    auto valOrErr = ToResultInvoke(foo, &TestClass::NonOverloadedNoInput);
+    static_assert(std::is_same_v<decltype(valOrErr), Result<int, nsresult>>);
+    ASSERT_TRUE(valOrErr.isOk());
+    ASSERT_EQ(TestClass::kTestValue, valOrErr.unwrap());
+  }
+
+  // failure
+  {
+    auto valOrErr = ToResultInvoke(foo, &TestClass::NonOverloadedNoInputFails);
+    static_assert(std::is_same_v<decltype(valOrErr), Result<int, nsresult>>);
+    ASSERT_TRUE(valOrErr.isErr());
+    ASSERT_EQ(NS_ERROR_FAILURE, valOrErr.unwrapErr());
+  }
+}
+
+TEST(ResultExtensions_ToResultInvoke, MemberFunction_NoInput_Const)
+{
+  const TestClass foo;
+
+  // success
+  {
+    auto valOrErr = ToResultInvoke(foo, &TestClass::NonOverloadedNoInputConst);
+    static_assert(std::is_same_v<decltype(valOrErr), Result<int, nsresult>>);
+    ASSERT_TRUE(valOrErr.isOk());
+    ASSERT_EQ(TestClass::kTestValue, valOrErr.unwrap());
+  }
+
+  // failure
+  {
+    auto valOrErr =
+        ToResultInvoke(foo, &TestClass::NonOverloadedNoInputFailsConst);
+    static_assert(std::is_same_v<decltype(valOrErr), Result<int, nsresult>>);
+    ASSERT_TRUE(valOrErr.isErr());
+    ASSERT_EQ(NS_ERROR_FAILURE, valOrErr.unwrapErr());
+  }
+}
+
+TEST(ResultExtensions_ToResultInvoke, MemberFunction_NoInput_Ref)
+{
+  TestClass foo;
+
+  // success
+  {
+    auto valOrErr = ToResultInvoke(foo, &TestClass::NonOverloadedNoInputRef);
+    static_assert(std::is_same_v<decltype(valOrErr), Result<int, nsresult>>);
+    ASSERT_TRUE(valOrErr.isOk());
+    ASSERT_EQ(TestClass::kTestValue, valOrErr.unwrap());
+  }
+
+  // failure
+  {
+    auto valOrErr =
+        ToResultInvoke(foo, &TestClass::NonOverloadedNoInputFailsRef);
+    static_assert(std::is_same_v<decltype(valOrErr), Result<int, nsresult>>);
+    ASSERT_TRUE(valOrErr.isErr());
+    ASSERT_EQ(NS_ERROR_FAILURE, valOrErr.unwrapErr());
+  }
+}
+
+TEST(ResultExtensions_ToResultInvoke, MemberFunction_WithInput)
+{
+  TestClass foo;
+
+  // success
+  {
+    auto valOrErr = ToResultInvoke(foo, &TestClass::NonOverloadedWithInput,
+                                   -TestClass::kTestValue);
+    static_assert(std::is_same_v<decltype(valOrErr), Result<int, nsresult>>);
+    ASSERT_TRUE(valOrErr.isOk());
+    ASSERT_EQ(-TestClass::kTestValue, valOrErr.unwrap());
+  }
+
+  // failure
+  {
+    auto valOrErr = ToResultInvoke(foo, &TestClass::NonOverloadedWithInputFails,
+                                   -TestClass::kTestValue);
+    static_assert(std::is_same_v<decltype(valOrErr), Result<int, nsresult>>);
+    ASSERT_TRUE(valOrErr.isErr());
+    ASSERT_EQ(NS_ERROR_FAILURE, valOrErr.unwrapErr());
+  }
+}
+
+TEST(ResultExtensions_ToResultInvoke, MemberFunction_NoOutput)
+{
+  TestClass foo;
+
+  // success
+  {
+    auto valOrErr = ToResultInvoke(foo, &TestClass::NonOverloadedNoOutput,
+                                   -TestClass::kTestValue);
+    static_assert(std::is_same_v<decltype(valOrErr), Result<Ok, nsresult>>);
+    ASSERT_TRUE(valOrErr.isOk());
+  }
+
+  // failure
+  {
+    auto valOrErr = ToResultInvoke(foo, &TestClass::NonOverloadedNoOutputFails,
+                                   -TestClass::kTestValue);
+    static_assert(std::is_same_v<decltype(valOrErr), Result<Ok, nsresult>>);
+    ASSERT_TRUE(valOrErr.isErr());
+    ASSERT_EQ(NS_ERROR_FAILURE, valOrErr.unwrapErr());
+  }
+}
+
+TEST(ResultExtensions_ToResultInvoke, MemberFunction_NoInput_Macro)
+{
+  TestClass foo;
+
+  // success
+  {
+    auto valOrErr = MOZ_TO_RESULT_INVOKE(foo, NonOverloadedNoInput);
+    static_assert(std::is_same_v<decltype(valOrErr), Result<int, nsresult>>);
+    ASSERT_TRUE(valOrErr.isOk());
+    ASSERT_EQ(TestClass::kTestValue, valOrErr.unwrap());
+  }
+
+  // failure
+  {
+    auto valOrErr = MOZ_TO_RESULT_INVOKE(foo, NonOverloadedNoInputFails);
+    static_assert(std::is_same_v<decltype(valOrErr), Result<int, nsresult>>);
+    ASSERT_TRUE(valOrErr.isErr());
+    ASSERT_EQ(NS_ERROR_FAILURE, valOrErr.unwrapErr());
+  }
+}
+
+TEST(ResultExtensions_ToResultInvoke, MemberFunction_NoInput_Const_Macro)
+{
+  const TestClass foo;
+
+  // success
+  {
+    auto valOrErr = MOZ_TO_RESULT_INVOKE(foo, NonOverloadedNoInputConst);
+    static_assert(std::is_same_v<decltype(valOrErr), Result<int, nsresult>>);
+    ASSERT_TRUE(valOrErr.isOk());
+    ASSERT_EQ(TestClass::kTestValue, valOrErr.unwrap());
+  }
+
+  // failure
+  {
+    auto valOrErr = MOZ_TO_RESULT_INVOKE(foo, NonOverloadedNoInputFailsConst);
+    static_assert(std::is_same_v<decltype(valOrErr), Result<int, nsresult>>);
+    ASSERT_TRUE(valOrErr.isErr());
+    ASSERT_EQ(NS_ERROR_FAILURE, valOrErr.unwrapErr());
+  }
+}
+
+TEST(ResultExtensions_ToResultInvoke, MemberFunction_NoInput_Ref_Macro)
+{
+  TestClass foo;
+
+  // success
+  {
+    auto valOrErr = MOZ_TO_RESULT_INVOKE(foo, NonOverloadedNoInputRef);
+    static_assert(std::is_same_v<decltype(valOrErr), Result<int, nsresult>>);
+    ASSERT_TRUE(valOrErr.isOk());
+    ASSERT_EQ(TestClass::kTestValue, valOrErr.unwrap());
+  }
+
+  // failure
+  {
+    auto valOrErr = MOZ_TO_RESULT_INVOKE(foo, NonOverloadedNoInputFailsRef);
+    static_assert(std::is_same_v<decltype(valOrErr), Result<int, nsresult>>);
+    ASSERT_TRUE(valOrErr.isErr());
+    ASSERT_EQ(NS_ERROR_FAILURE, valOrErr.unwrapErr());
+  }
+}
+
+TEST(ResultExtensions_ToResultInvoke, MemberFunction_WithInput_Macro)
+{
+  TestClass foo;
+
+  // success
+  {
+    auto valOrErr = MOZ_TO_RESULT_INVOKE(foo, NonOverloadedWithInput,
+                                         -TestClass::kTestValue);
+    static_assert(std::is_same_v<decltype(valOrErr), Result<int, nsresult>>);
+    ASSERT_TRUE(valOrErr.isOk());
+    ASSERT_EQ(-TestClass::kTestValue, valOrErr.unwrap());
+  }
+
+  // failure
+  {
+    auto valOrErr = MOZ_TO_RESULT_INVOKE(foo, NonOverloadedWithInputFails,
+                                         -TestClass::kTestValue);
+    static_assert(std::is_same_v<decltype(valOrErr), Result<int, nsresult>>);
+    ASSERT_TRUE(valOrErr.isErr());
+    ASSERT_EQ(NS_ERROR_FAILURE, valOrErr.unwrapErr());
+  }
+}
+
+TEST(ResultExtensions_ToResultInvoke, MemberFunction_NoOutput_Macro)
+{
+  TestClass foo;
+
+  // success
+  {
+    auto valOrErr = MOZ_TO_RESULT_INVOKE(foo, NonOverloadedNoOutput,
+                                         -TestClass::kTestValue);
+    static_assert(std::is_same_v<decltype(valOrErr), Result<Ok, nsresult>>);
+    ASSERT_TRUE(valOrErr.isOk());
+  }
+
+  // failure
+  {
+    auto valOrErr = MOZ_TO_RESULT_INVOKE(foo, NonOverloadedNoOutputFails,
+                                         -TestClass::kTestValue);
+    static_assert(std::is_same_v<decltype(valOrErr), Result<Ok, nsresult>>);
+    ASSERT_TRUE(valOrErr.isErr());
+    ASSERT_EQ(NS_ERROR_FAILURE, valOrErr.unwrapErr());
+  }
+}
+
+TEST(ResultExtensions_ToResultInvoke, PolymorphicPointerResult_nsCOMPtr_Result)
+{
+  TestClass foo;
+
+  // success
+  {
+    auto valOrErr = ToResultInvoke<nsCOMPtr<nsIFile>>(
+        std::mem_fn(&TestClass::PolymorphicNoInput), foo);
+    static_assert(std::is_same_v<decltype(valOrErr),
+                                 Result<nsCOMPtr<nsIFile>, nsresult>>);
+    ASSERT_TRUE(valOrErr.isOk());
+    ASSERT_NE(nullptr, valOrErr.inspect());
+
+    ASSERT_EQ(ToResultInvoke<nsString>(std::mem_fn(&nsIFile::GetPath),
+                                       *MakeRefPtr<nsLocalFile>())
+                  .inspect(),
+              ToResultInvoke<nsString>(std::mem_fn(&nsIFile::GetPath),
+                                       valOrErr.inspect())
+                  .inspect());
+  }
+
+  // failure
+  {
+    auto valOrErr = ToResultInvoke<nsCOMPtr<nsIFile>>(
+        std::mem_fn(&TestClass::PolymorphicNoInputFails), foo);
+    static_assert(std::is_same_v<decltype(valOrErr),
+                                 Result<nsCOMPtr<nsIFile>, nsresult>>);
+    ASSERT_TRUE(valOrErr.isErr());
+    ASSERT_EQ(NS_ERROR_FAILURE, valOrErr.unwrapErr());
+  }
+}
+
+TEST(ResultExtensions_ToResultInvoke, RefPtr_MemberFunction_NoInput)
+{
+  auto foo = MakeRefPtr<RefCountedTestClass>();
+
+  // success
+  {
+    auto valOrErr =
+        ToResultInvoke(foo, &RefCountedTestClass::NonOverloadedNoInput);
+    static_assert(std::is_same_v<decltype(valOrErr), Result<int, nsresult>>);
+    ASSERT_TRUE(valOrErr.isOk());
+    ASSERT_EQ(TestClass::kTestValue, valOrErr.unwrap());
+  }
+
+  // failure
+  {
+    auto valOrErr =
+        ToResultInvoke(foo, &RefCountedTestClass::NonOverloadedNoInputFails);
+    static_assert(std::is_same_v<decltype(valOrErr), Result<int, nsresult>>);
+    ASSERT_TRUE(valOrErr.isErr());
+    ASSERT_EQ(NS_ERROR_FAILURE, valOrErr.unwrapErr());
+  }
+}
+
+TEST(ResultExtensions_ToResultInvoke, RefPtr_MemberFunction_NoInput_Macro)
+{
+  auto foo = MakeRefPtr<RefCountedTestClass>();
+
+  // success
+  {
+    auto valOrErr = MOZ_TO_RESULT_INVOKE(foo, NonOverloadedNoInput);
+    static_assert(std::is_same_v<decltype(valOrErr), Result<int, nsresult>>);
+    ASSERT_TRUE(valOrErr.isOk());
+    ASSERT_EQ(TestClass::kTestValue, valOrErr.unwrap());
+  }
+
+  // failure
+  {
+    auto valOrErr = MOZ_TO_RESULT_INVOKE(foo, NonOverloadedNoInputFails);
+    static_assert(std::is_same_v<decltype(valOrErr), Result<int, nsresult>>);
+    ASSERT_TRUE(valOrErr.isErr());
+    ASSERT_EQ(NS_ERROR_FAILURE, valOrErr.unwrapErr());
+  }
+}
+
+TEST(ResultExtensions_ToResultInvoke, RawPtr_MemberFunction_NoInput_Macro)
+{
+  auto foo = MakeRefPtr<RefCountedTestClass>();
+  auto* fooPtr = foo.get();
+
+  // success
+  {
+    auto valOrErr = MOZ_TO_RESULT_INVOKE(fooPtr, NonOverloadedNoInput);
+    static_assert(std::is_same_v<decltype(valOrErr), Result<int, nsresult>>);
+    ASSERT_TRUE(valOrErr.isOk());
+    ASSERT_EQ(TestClass::kTestValue, valOrErr.unwrap());
+  }
+
+  // failure
+  {
+    auto valOrErr = MOZ_TO_RESULT_INVOKE(fooPtr, NonOverloadedNoInputFails);
+    static_assert(std::is_same_v<decltype(valOrErr), Result<int, nsresult>>);
+    ASSERT_TRUE(valOrErr.isErr());
+    ASSERT_EQ(NS_ERROR_FAILURE, valOrErr.unwrapErr());
+  }
+}
+
+TEST(ResultExtensions_ToResultInvoke, nsCOMPtr_NS_IMETHOD_bool_Result)
+{
+  nsCOMPtr<nsIFile> file = MakeAndAddRef<nsLocalFile>();
+  ASSERT_TRUE(ToResultInvoke(file, &nsIFile::Equals, file).isOk());
+}
+
+TEST(ResultExtensions_ToResultInvoke, RawPtr_AbstractClass_MemberFunction_Macro)
+{
+  nsCOMPtr<nsIFile> file = MakeAndAddRef<nsLocalFile>();
+  auto* filePtr = file.get();
+
+  auto valOrErr = MOZ_TO_RESULT_INVOKE(filePtr, Equals, file);
+  static_assert(std::is_same_v<decltype(valOrErr), Result<bool, nsresult>>);
+  ASSERT_TRUE(valOrErr.isOk());
+  ASSERT_EQ(true, valOrErr.unwrap());
+}
+
+TEST(ResultExtensions_ToResultInvoke,
+     RawPtr_AbstractClass_MemberFunction_NoInput_Macro_Typed)
+{
+  nsCOMPtr<nsIFile> file = MakeAndAddRef<nsLocalFile>();
+  auto* filePtr = file.get();
+
+  auto valOrErr = MOZ_TO_RESULT_INVOKE_TYPED(nsCOMPtr<nsIFile>, filePtr, Clone);
+  static_assert(
+      std::is_same_v<decltype(valOrErr), Result<nsCOMPtr<nsIFile>, nsresult>>);
+  ASSERT_TRUE(valOrErr.isOk());
+  ASSERT_NE(nullptr, valOrErr.unwrap());
+}
diff --git a/mfbt/tests/gtest/TestReverseIterator.cpp b/mfbt/tests/gtest/TestReverseIterator.cpp
new file mode 100644
index 0000000000..53a53439c8
--- /dev/null
+++ b/mfbt/tests/gtest/TestReverseIterator.cpp
@@ -0,0 +1,102 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "gtest/gtest.h"
+
+#include "mozilla/ReverseIterator.h"
+
+using namespace mozilla;
+
+TEST(ReverseIterator, Const_RangeBasedFor)
+{
+  const std::vector<int> in = {1, 2, 3, 4};
+  const auto reversedRange =
+      detail::IteratorRange<ReverseIterator<std::vector<int>::const_iterator>>{
+          ReverseIterator{in.end()}, ReverseIterator{in.begin()}};
+
+  const std::vector<int> expected = {4, 3, 2, 1};
+  std::vector<int> out;
+  for (auto i : reversedRange) {
+    out.emplace_back(i);
+  }
+
+  EXPECT_EQ(expected, out);
+}
+
+TEST(ReverseIterator, NonConst_RangeBasedFor)
+{
+  std::vector<int> in = {1, 2, 3, 4};
+  auto reversedRange =
+      detail::IteratorRange<ReverseIterator<std::vector<int>::iterator>>{
+          ReverseIterator{in.end()}, ReverseIterator{in.begin()}};
+
+  const std::vector<int> expected = {-1, -2, -3, -4};
+  for (auto& i : reversedRange) {
+    i = -i;
+  }
+
+  EXPECT_EQ(expected, in);
+}
+
+TEST(ReverseIterator, Difference)
+{
+  const std::vector<int> in = {1, 2, 3, 4};
+  using reverse_iterator = ReverseIterator<std::vector<int>::const_iterator>;
+
+  reverse_iterator rbegin = reverse_iterator{in.end()},
+                   rend = reverse_iterator{in.begin()};
+  EXPECT_EQ(4, rend - rbegin);
+  EXPECT_EQ(0, rend - rend);
+  EXPECT_EQ(0, rbegin - rbegin);
+
+  --rend;
+  EXPECT_EQ(3, rend - rbegin);
+
+  ++rbegin;
+  EXPECT_EQ(2, rend - rbegin);
+
+  rend--;
+  EXPECT_EQ(1, rend - rbegin);
+
+  rbegin++;
+  EXPECT_EQ(0, rend - rbegin);
+}
+
+TEST(ReverseIterator, Comparison)
+{
+  const std::vector<int> in = {1, 2, 3, 4};
+  using reverse_iterator = ReverseIterator<std::vector<int>::const_iterator>;
+
+  reverse_iterator rbegin = reverse_iterator{in.end()},
+                   rend = reverse_iterator{in.begin()};
+  EXPECT_TRUE(rbegin < rend);
+  EXPECT_FALSE(rend < rbegin);
+  EXPECT_FALSE(rend < rend);
+  EXPECT_FALSE(rbegin < rbegin);
+
+  EXPECT_TRUE(rend > rbegin);
+  EXPECT_FALSE(rbegin > rend);
+  EXPECT_FALSE(rend > rend);
+  EXPECT_FALSE(rbegin > rbegin);
+
+  EXPECT_TRUE(rbegin <= rend);
+  EXPECT_FALSE(rend <= rbegin);
+  EXPECT_TRUE(rend <= rend);
+  EXPECT_TRUE(rbegin <= rbegin);
+
+  EXPECT_TRUE(rend >= rbegin);
+  EXPECT_FALSE(rbegin >= rend);
+  EXPECT_TRUE(rend >= rend);
+  EXPECT_TRUE(rbegin >= rbegin);
+
+  EXPECT_FALSE(rend == rbegin);
+  EXPECT_FALSE(rbegin == rend);
+  EXPECT_TRUE(rend == rend);
+  EXPECT_TRUE(rbegin == rbegin);
+
+  EXPECT_TRUE(rend != rbegin);
+  EXPECT_TRUE(rbegin != rend);
+  EXPECT_FALSE(rend != rend);
+  EXPECT_FALSE(rbegin != rbegin);
+}
diff --git a/mfbt/tests/gtest/TestSpan.cpp b/mfbt/tests/gtest/TestSpan.cpp
index ba8d91ac4e..fce32d4c28 100644
--- a/mfbt/tests/gtest/TestSpan.cpp
+++ b/mfbt/tests/gtest/TestSpan.cpp
@@ -26,38 +26,40 @@
 #include "mozilla/Range.h"
 #include "mozilla/TypeTraits.h"
 
+#include <type_traits>
+
 #define SPAN_TEST(name) TEST(SpanTest, name)
 #define CHECK_THROW(a, b)
 
 using namespace mozilla;
 
-static_assert(IsConvertible<Range<int>, Span<const int>>::value,
+static_assert(std::is_convertible_v<Range<int>, Span<const int>>,
               "Range should convert into const");
-static_assert(IsConvertible<Range<const int>, Span<const int>>::value,
+static_assert(std::is_convertible_v<Range<const int>, Span<const int>>,
               "const Range should convert into const");
-static_assert(!IsConvertible<Range<const int>, Span<int>>::value,
+static_assert(!std::is_convertible_v<Range<const int>, Span<int>>,
               "Range should not drop const in conversion");
-static_assert(IsConvertible<Span<int>, Range<const int>>::value,
+static_assert(std::is_convertible_v<Span<int>, Range<const int>>,
               "Span should convert into const");
-static_assert(IsConvertible<Span<const int>, Range<const int>>::value,
+static_assert(std::is_convertible_v<Span<const int>, Range<const int>>,
               "const Span should convert into const");
-static_assert(!IsConvertible<Span<const int>, Range<int>>::value,
+static_assert(!std::is_convertible_v<Span<const int>, Range<int>>,
               "Span should not drop const in conversion");
-static_assert(IsConvertible<Span<const int>, Span<const int>>::value,
+static_assert(std::is_convertible_v<Span<const int>, Span<const int>>,
               "const Span should convert into const");
-static_assert(IsConvertible<Span<int>, Span<const int>>::value,
+static_assert(std::is_convertible_v<Span<int>, Span<const int>>,
               "Span should convert into const");
-static_assert(!IsConvertible<Span<const int>, Span<int>>::value,
+static_assert(!std::is_convertible_v<Span<const int>, Span<int>>,
               "Span should not drop const in conversion");
-static_assert(IsConvertible<const nsTArray<int>, Span<const int>>::value,
+static_assert(std::is_convertible_v<const nsTArray<int>, Span<const int>>,
               "const nsTArray should convert into const");
-static_assert(IsConvertible<nsTArray<int>, Span<const int>>::value,
+static_assert(std::is_convertible_v<nsTArray<int>, Span<const int>>,
               "nsTArray should convert into const");
-static_assert(!IsConvertible<const nsTArray<int>, Span<int>>::value,
+static_assert(!std::is_convertible_v<const nsTArray<int>, Span<int>>,
               "nsTArray should not drop const in conversion");
-static_assert(IsConvertible<nsTArray<const int>, Span<const int>>::value,
+static_assert(std::is_convertible_v<nsTArray<const int>, Span<const int>>,
               "nsTArray should convert into const");
-static_assert(!IsConvertible<nsTArray<const int>, Span<int>>::value,
+static_assert(!std::is_convertible_v<nsTArray<const int>, Span<int>>,
               "nsTArray should not drop const in conversion");
 
 /**
@@ -2219,6 +2221,31 @@ SPAN_TEST(split_at_static) {
   static_assert(splitAt3Result.second.Elements() == s.Elements() + 3);
 }
 
+SPAN_TEST(as_const_dynamic) {
+  static int arr[5] = {1, 2, 3, 4, 5};
+  auto span = Span{arr, 5};
+  auto constSpan = span.AsConst();
+  static_assert(std::is_same_v<Span<const int>, decltype(constSpan)>);
+}
+
+SPAN_TEST(as_const_static) {
+  {
+    static constexpr int constArr[5] = {1, 2, 3, 4, 5};
+    constexpr auto span = Span{constArr};  // is already a Span<const int>
+    constexpr auto constSpan = span.AsConst();
+
+    static_assert(
+        std::is_same_v<const Span<const int, 5>, decltype(constSpan)>);
+  }
+
+  {
+    static int arr[5] = {1, 2, 3, 4, 5};
+    auto span = Span{arr};
+    auto constSpan = span.AsConst();
+    static_assert(std::is_same_v<Span<const int, 5>, decltype(constSpan)>);
+  }
+}
+
 SPAN_TEST(construct_from_iterators_dynamic) {
   const int constArr[5] = {1, 2, 3, 4, 5};
   auto constSpan = Span{constArr};
diff --git a/mfbt/tests/gtest/moz.build b/mfbt/tests/gtest/moz.build
index d2e1b3e5c6..b00483dd6c 100644
--- a/mfbt/tests/gtest/moz.build
+++ b/mfbt/tests/gtest/moz.build
@@ -9,7 +9,9 @@ UNIFIED_SOURCES += [
 ]
 
 SOURCES += [
+    'TestAlgorithm.cpp',
     'TestInitializedOnce.cpp',
+    'TestResultExtensions.cpp',
 ]
 
 if not CONFIG['MOZILLA_OFFICIAL']:
diff --git a/mfbt/tests/moz.build b/mfbt/tests/moz.build
index a6c4b15213..45b753b860 100644
--- a/mfbt/tests/moz.build
+++ b/mfbt/tests/moz.build
@@ -20,6 +20,7 @@ CppUnitTests([
     'TestCasting',
     'TestCeilingFloor',
     'TestCheckedInt',
+    'TestCompactPair.cpp',
     'TestCountPopulation',
     'TestCountZeroes',
     'TestDefineEnum',
@@ -43,7 +44,6 @@ CppUnitTests([
     'TestMaybe',
     'TestNonDereferenceable',
     'TestNotNull',
-    'TestPair',
     'TestRandomNum',
     'TestRange',
     'TestRefPtr',
diff --git a/mobile/android/chrome/content/RemoteDebugger.js b/mobile/android/chrome/content/RemoteDebugger.js
index 0a5830ac1d..438098a7ed 100644
--- a/mobile/android/chrome/content/RemoteDebugger.js
+++ b/mobile/android/chrome/content/RemoteDebugger.js
@@ -10,7 +10,7 @@ XPCOMUtils.defineLazyGetter(this, "require", () => {
 });
 
 XPCOMUtils.defineLazyGetter(this, "DebuggerServer", () => {
-  let { DebuggerServer } = require("devtools/server/main");
+  let { DebuggerServer } = require("devtools/server/debugger-server");
   return DebuggerServer;
 });
 XPCOMUtils.defineLazyGetter(this, "SocketListener", () => {
diff --git a/mobile/android/modules/Sanitizer.jsm b/mobile/android/modules/Sanitizer.jsm
index f244e4a200..3781ea09a6 100644
--- a/mobile/android/modules/Sanitizer.jsm
+++ b/mobile/android/modules/Sanitizer.jsm
@@ -2,8 +2,6 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-/* globals LoadContextInfo, FormHistory, Accounts */
-
 const { Services } = ChromeUtils.import("resource://gre/modules/Services.jsm");
 const { XPCOMUtils } = ChromeUtils.import(
   "resource://gre/modules/XPCOMUtils.jsm"
diff --git a/mobile/android/modules/geckoview/GeckoViewRemoteDebugger.jsm b/mobile/android/modules/geckoview/GeckoViewRemoteDebugger.jsm
index b49852d785..7345c0bbf0 100644
--- a/mobile/android/modules/geckoview/GeckoViewRemoteDebugger.jsm
+++ b/mobile/android/modules/geckoview/GeckoViewRemoteDebugger.jsm
@@ -25,7 +25,7 @@ XPCOMUtils.defineLazyGetter(this, "require", () => {
 });
 
 XPCOMUtils.defineLazyGetter(this, "DebuggerServer", () => {
-  const { DebuggerServer } = require("devtools/server/main");
+  const { DebuggerServer } = require("devtools/server/debugger-server");
   return DebuggerServer;
 });
 
diff --git a/mobile/android/tests/browser/chrome/test_debugger_server.html b/mobile/android/tests/browser/chrome/test_debugger_server.html
index e6eafa0cc5..1d11697869 100644
--- a/mobile/android/tests/browser/chrome/test_debugger_server.html
+++ b/mobile/android/tests/browser/chrome/test_debugger_server.html
@@ -19,7 +19,7 @@ Migrated from Robocop: https://bugzilla.mozilla.org/show_bug.cgi?id=1184186
   const {Services} = ChromeUtils.import("resource://gre/modules/Services.jsm");
   const { require } =
     ChromeUtils.import("resource://devtools/shared/Loader.jsm");
-  const { DebuggerServer } = require("devtools/server/main");
+  const { DebuggerServer } = require("devtools/server/debugger-server");
 
   let win = Services.wm.getMostRecentWindow("navigator:browser");
 
diff --git a/modules/libpref/components.conf b/modules/libpref/components.conf
index 60ff7686e4..ddbd6c25d5 100644
--- a/modules/libpref/components.conf
+++ b/modules/libpref/components.conf
@@ -10,8 +10,10 @@ UnloadFunc = 'mozilla::UnloadPrefsModule'
 
 Classes = [
     {
+        'js_name': 'prefs',
         'cid': '{91ca2441-050f-4f7c-9df8-75b40ea40156}',
         'contract_ids': ['@mozilla.org/preferences-service;1'],
+        'interfaces': ['nsIPrefService', 'nsIPrefBranch'],
         'singleton': True,
         'type': 'mozilla::Preferences',
         'headers': ['mozilla/Preferences.h'],
diff --git a/modules/libpref/greprefs.js b/modules/libpref/greprefs.js
index 9fb53498f0..942e968567 100644
--- a/modules/libpref/greprefs.js
+++ b/modules/libpref/greprefs.js
@@ -1,2 +1 @@
 #include init/all.js
-#include ../../devtools/shared/preferences/devtools-shared.js
diff --git a/modules/libpref/init/StaticPrefList.yaml b/modules/libpref/init/StaticPrefList.yaml
index 06ba38b8f5..ca9b2b4b80 100644
--- a/modules/libpref/init/StaticPrefList.yaml
+++ b/modules/libpref/init/StaticPrefList.yaml
@@ -1010,6 +1010,12 @@
   value: false
   mirror: always
 
+# Provide ability to turn on support for canvas mozGetAsFile API.
+- name: canvas.mozgetasfile.enabled
+  type: bool
+  value: false
+  mirror: always
+
 #---------------------------------------------------------------------------
 # Prefs starting with "channelclassifier."
 #---------------------------------------------------------------------------
@@ -1257,7 +1263,7 @@
 # Is support for AudioWorklet enabled?
 - name: dom.audioworklet.enabled
   type: bool
-  value: false
+  value: @IS_NIGHTLY_BUILD@
   mirror: always
 
 # Is support for Navigator.getBattery enabled?
@@ -1339,7 +1345,7 @@
 # HTML <dialog> element
 - name: dom.dialog_element.enabled
   type: bool
-  value: false
+  value: true
   mirror: always
 
 # Only propagate the open window click permission if the setTimeout() is equal
@@ -1951,11 +1957,25 @@
   value: false
   mirror: always
 
-# Is support for Navigator.registerContentHandler enabled?
-- name: dom.registerContentHandler.enabled
-  type: bool
-  value: false
-  mirror: always
+#ifdef XP_WIN
+  # Preference that is used to set nsILocalFileWin::useDOSDevicePathSyntax
+  # attribute for all local file instances created by QuotaManager and its
+  # clients. The value of this preference is cached so changing the preference
+  # during runtime has no effect.
+  # See bug 1626846 for setting this to false by default.
+-   name: dom.quotaManager.useDOSDevicePathSyntax
+    type: RelaxedAtomicBool
+    value: true
+    mirror: always
+    do_not_use_directly: true
+
+  # Preference that is used to enable the hack for overrriding xFullPathname in
+  # TelemetryVFS.
+-   name: dom.quotaManager.overrideXFullPathname
+    type: RelaxedAtomicBool
+    value: true
+    mirror: always
+#endif
 
 # Reporting API.
 - name: dom.reporting.enabled
@@ -2008,18 +2028,6 @@
   value: true
   mirror: always
 
-#ifdef JS_BUILD_BINAST
--   name: dom.script_loader.binast_encoding.domain.restrict
-    type: bool
-    value: true
-    mirror: always
-
--   name: dom.script_loader.binast_encoding.enabled
-    type: RelaxedAtomicBool
-    value: false
-    mirror: always
-#endif
-
 # Whether to enable the JavaScript start-up cache. This causes one of the first
 # execution to record the bytecode of the JavaScript function used, and save it
 # in the existing cache entry. On the following loads of the same script, the
@@ -2057,6 +2065,31 @@
   value: true
   mirror: always
 
+# Enable  speculative off main thread parsing of external scripts as
+# soon as they are fetched.
+- name: dom.script_loader.external_scripts.speculative_omt_parse.enabled
+  type: bool
+  value: @IS_NIGHTLY_BUILD@
+  mirror: always
+
+# Speculatively compile non parser inserted scripts
+- name: dom.script_loader.external_scripts.speculate_non_parser_inserted.enabled
+  type: bool
+  value: false
+  mirror: always
+
+# Speculatively compile async scripts
+- name: dom.script_loader.external_scripts.speculate_async.enabled
+  type: bool
+  value: false
+  mirror: always
+
+# Speculatively compile link preload scripts
+- name: dom.script_loader.external_scripts.speculate_link_preload.enabled
+  type: bool
+  value: false
+  mirror: always
+
 - name: dom.securecontext.whitelist_onions
   type: bool
   value: false
@@ -2121,6 +2154,11 @@
   value: false
   mirror: always
 
+- name: dom.workers.serialized-sab-access
+  type: RelaxedAtomicBool
+  value: false
+  mirror: always
+
 # External.AddSearchProvider is deprecated and it will be removed in the next
 # cycles.
 - name: dom.sidebar.enabled
@@ -2697,7 +2735,7 @@
 
 - name: dom.worklet.enabled
   type: bool
-  value: false
+  value: @IS_NIGHTLY_BUILD@
   mirror: always
 
 # Enable content type normalization of XHR uploads via MIME Sniffing standard
@@ -3893,20 +3931,19 @@
   value: @IS_NOT_RELEASE_OR_BETA@
   mirror: always
 
-#ifdef NIGHTLY_BUILD
-  # Experimental support for weak references in JavaScript (WeakRef and
-  # FinalizationRegistry).
-- name: javascript.options.experimental.weakrefs.enabled
+# Support for weak references in JavaScript (WeakRef and FinalizationRegistry).
+- name: javascript.options.weakrefs
   type: RelaxedAtomicBool
-  value: false
+  value: true
   mirror: always
 
-  # Whether to expose the FinalizationRegistry.prototype.cleanupSome method.
+# Whether to expose the FinalizationRegistry.prototype.cleanupSome method.
 - name: javascript.options.experimental.weakrefs.expose_cleanupSome
   type: RelaxedAtomicBool
   value: false
   mirror: always
 
+#ifdef NIGHTLY_BUILD
   # Experimental support for Iterator Helpers in JavaScript.
 - name: javascript.options.experimental.iterator_helpers
   type: RelaxedAtomicBool
@@ -3914,6 +3951,18 @@
   mirror: always
 #endif
 
+  # Support for Private Fields in JavaScript.
+- name: javascript.options.experimental.private_fields
+  type: RelaxedAtomicBool
+  value: true
+  mirror: always
+
+  # Experimental support for Private Methods in JavaScript.
+- name: javascript.options.experimental.private_methods
+  type: RelaxedAtomicBool
+  value: true
+  mirror: always
+
 # The amount of time we wait between a request to GC (due to leaving a page) and doing the actual GC, in ms.
 - name: javascript.options.gc_delay
   type: uint32_t
@@ -3989,6 +4038,14 @@
 #endif
   mirror: always
 
+# True if off-thread parsing should use a parse GlobalObject in order to
+# directly allocate to the GC from a helper thread. If false, transfer the
+# CompilationStencil back to main thread before allocating GC objects.
+- name: javascript.options.off_thread_parse_global
+  type: bool
+  value: true
+  mirror: once
+
 #---------------------------------------------------------------------------
 # Prefs starting with "keyword."
 #---------------------------------------------------------------------------
diff --git a/modules/libpref/init/all.js b/modules/libpref/init/all.js
index 780071c9c2..a7f5b7c34b 100644
--- a/modules/libpref/init/all.js
+++ b/modules/libpref/init/all.js
@@ -278,14 +278,6 @@ pref("dom.keyboardevent.keypress.hack.use_legacy_keycode_and_charcode.addl", "")
 // explanation for the detail.
 pref("dom.mouseevent.click.hack.use_legacy_non-primary_dispatch", "");
 
-#ifdef JS_BUILD_BINAST
-  // Until we're satisfied that it works nicely, we're restricting
-  // BinAST to a few partner sites:
-  // - A subset of Facebook
-  // - A subset of Cloudflare
-  pref("dom.script_loader.binast_encoding.domain.restrict.list", "*.facebook.com,static.xx.fbcdn.net,*.cloudflare.com,*.cloudflarestream.com,unpkg.com");
-#endif
-
 // Fastback caching - if this pref is negative, then we calculate the number
 // of content viewers to cache based on the amount of available memory.
 pref("browser.sessionhistory.max_total_viewers", -1);
@@ -489,6 +481,10 @@ pref("media.videocontrols.picture-in-picture.video-toggle.flyout-wait-ms", 5000)
   pref("media.peerconnection.ice.proxy_only", false);
   pref("media.peerconnection.turn.disable", false);
 
+  // 770 = DTLS 1.0, 771 = DTLS 1.2
+  pref("media.peerconnection.dtls.version.min", 770);
+  pref("media.peerconnection.dtls.version.max", 771);
+
   // These values (aec, agc, and noise) are from:
   // media/webrtc/trunk/webrtc/modules/audio_processing/include/audio_processing.h
   #if defined(MOZ_WEBRTC_HARDWARE_AEC_NS)
@@ -1007,6 +1003,9 @@ pref("javascript.options.baselinejit",      true);
 // Duplicated in JitOptions - ensure both match.
 pref("javascript.options.baselinejit.threshold", 100);
 pref("javascript.options.ion",              true);
+#ifdef NIGHTLY_BUILD
+pref("javascript.options.warp",             false);
+#endif
 // Duplicated in JitOptions - ensure both match.
 pref("javascript.options.ion.threshold",    1000);
 pref("javascript.options.ion.full.threshold", 100000);
@@ -1030,11 +1029,12 @@ pref("javascript.options.wasm_baselinejit",       true);
 pref("javascript.options.native_regexp",    true);
 pref("javascript.options.parallel_parsing", true);
 pref("javascript.options.source_pragmas",    true);
-#if !defined(RELEASE_OR_BETA) && !defined(ANDROID) && !defined(XP_IOS)
-  pref("javascript.options.asyncstack",       true);
-#else
-  pref("javascript.options.asyncstack",       false);
-#endif
+
+pref("javascript.options.asyncstack", true);
+// Broadly capturing async stack data adds overhead that is only advisable for
+// developers, so we only enable it when the devtools are open, by default.
+pref("javascript.options.asyncstack_capture_debuggee_only", true);
+
 pref("javascript.options.throw_on_asmjs_validation_failure", false);
 pref("javascript.options.ion.offthread_compilation", true);
 #ifdef DEBUG
@@ -1108,9 +1108,15 @@ pref("javascript.options.mem.gc_min_empty_chunk_count", 1);
 // JSGC_MAX_EMPTY_CHUNK_COUNT
 pref("javascript.options.mem.gc_max_empty_chunk_count", 30);
 
+// JSGC_HELPER_THREAD_RATIO
+pref("javascript.options.mem.gc_helper_thread_ratio", 50);
+
+// JSGC_MAX_HELPER_THREADS
+pref("javascript.options.mem.gc_max_helper_threads", 8);
+
 pref("javascript.options.showInConsole", false);
 
-pref("javascript.options.shared_memory", false);
+pref("javascript.options.shared_memory", true);
 
 pref("javascript.options.throw_on_debuggee_would_run", false);
 pref("javascript.options.dump_stack_on_debuggee_would_run", false);
@@ -2161,7 +2167,7 @@ pref("security.dialog_enable_delay", 1000);
 pref("security.notification_enable_delay", 500);
 
 #if defined(DEBUG) && !defined(ANDROID)
-  pref("csp.about_uris_without_csp", "blank,printpreview,srcdoc,about,addons,cache-entry,config,crashes,debugging,devtools,downloads,home,memory,networking,newtab,performance,plugins,policies,profiles,restartrequired,serviceworkers,sessionrestore,support,sync-log,telemetry,url-classifier");
+  pref("csp.about_uris_without_csp", "blank,printpreview,srcdoc,addons,config,downloads,home,newtab,preferences,sessionrestore,sync-log");
   // the following prefs are for testing purposes only.
   pref("csp.overrule_about_uris_without_csp_whitelist", false);
   pref("csp.skip_about_page_has_csp_assert", false);
@@ -4019,12 +4025,6 @@ pref("memory.blob_report.stack_frames", 0);
 // Activates the activity monitor
 pref("io.activity.enabled", false);
 
-// If true, reuse the same global for (almost) everything loaded by the component
-// loader (JS components, JSMs, etc). This saves memory, but makes it possible
-// for the scripts to interfere with each other.  A restart is required for this
-// to take effect.
-pref("jsloader.shareGlobal", true);
-
 // path to OSVR DLLs
 pref("gfx.vr.osvr.utilLibPath", "");
 pref("gfx.vr.osvr.commonLibPath", "");
@@ -4647,3 +4647,87 @@ pref("remote.force-local", true);
 // "Config", "Info", "Warn", "Error", and "Fatal". The value is treated
 // case-sensitively.
 pref("remote.log.level", "Info");
+
+// Enable the JSON View tool (an inspector for application/json documents).
+pref("devtools.jsonview.enabled", true);
+
+// Default theme ("dark" or "light").
+#ifdef MOZ_DEV_EDITION
+  pref("devtools.theme", "dark", sticky);
+#else
+  pref("devtools.theme", "light", sticky);
+#endif
+
+// Completely disable DevTools entry points, as well as all DevTools command
+// line arguments This should be merged with devtools.enabled, see Bug 1440675.
+pref("devtools.policy.disabled", false);
+
+// Tells if DevTools have been explicitely enabled by the user. This pref
+// allows to disable all features related to DevTools for users that never use
+// them. Until bug 1361080 lands, we always consider them enabled.
+pref("devtools.enabled", true);
+
+// Enable deprecation warnings.
+pref("devtools.errorconsole.deprecation_warnings", true);
+
+#ifdef NIGHTLY_BUILD
+  // Don't show the Browser Toolbox prompt on local builds / nightly.
+  pref("devtools.debugger.prompt-connection", false, sticky);
+#else
+  pref("devtools.debugger.prompt-connection", true, sticky);
+#endif
+
+#ifdef MOZILLA_OFFICIAL
+  // Disable debugging chrome.
+  pref("devtools.chrome.enabled", false, sticky);
+  // Disable remote debugging connections.
+  pref("devtools.debugger.remote-enabled", false, sticky);
+#else
+  // In local builds, enable the browser toolbox by default.
+  pref("devtools.chrome.enabled", true, sticky);
+  pref("devtools.debugger.remote-enabled", true, sticky);
+#endif
+
+// Disable remote debugging protocol logging.
+pref("devtools.debugger.log", false);
+pref("devtools.debugger.log.verbose", false);
+
+pref("devtools.debugger.remote-port", 6000);
+pref("devtools.debugger.remote-websocket", false);
+// Force debugger server binding on the loopback interface.
+pref("devtools.debugger.force-local", true);
+
+// Limit for intercepted request and response bodies (1 MB).
+// Possible values:
+// 0 => the response body has no limit
+// n => represents max number of bytes stored
+pref("devtools.netmonitor.responseBodyLimit", 1048576);
+pref("devtools.netmonitor.requestBodyLimit", 1048576);
+
+// Limit for WebSocket frames (100 KB).
+pref("devtools.netmonitor.ws.messageDataLimit", 100000);
+
+// DevTools default color unit.
+pref("devtools.defaultColorUnit", "authored");
+
+// Used for devtools debugging.
+pref("devtools.dump.emit", false);
+
+// Disable device discovery logging.
+pref("devtools.discovery.log", false);
+// Whether to scan for DevTools devices via WiFi.
+pref("devtools.remote.wifi.scan", true);
+// Client must complete TLS handshake within this window (ms).
+pref("devtools.remote.tls-handshake-timeout", 10000);
+
+// The extension ID for devtools-adb-extension.
+pref("devtools.remote.adb.extensionID", "adb@mozilla.org");
+// The URL for for devtools-adb-extension (overridden in tests to a local
+// path).
+pref("devtools.remote.adb.extensionURL", "https://ftp.mozilla.org/pub/mozilla.org/labs/devtools/adb-extension/#OS#/adb-extension-latest-#OS#.xpi");
+
+// URL of the remote JSON catalog used for device simulation.
+pref("devtools.devices.url", "https://code.cdn.mozilla.net/devices/devices.json");
+
+// Enable Inactive CSS detection; used both by the client and the server.
+pref("devtools.inspector.inactive.css.enabled", true);
diff --git a/mozglue/baseprofiler/core/ProfileBuffer.cpp b/mozglue/baseprofiler/core/ProfileBuffer.cpp
index b5731ec9db..ef680e94ff 100644
--- a/mozglue/baseprofiler/core/ProfileBuffer.cpp
+++ b/mozglue/baseprofiler/core/ProfileBuffer.cpp
@@ -8,51 +8,69 @@
 
 #  include "ProfileBuffer.h"
 
-#  include "ProfilerMarker.h"
-
 #  include "mozilla/MathAlgorithms.h"
 
 namespace mozilla {
 namespace baseprofiler {
 
-ProfileBuffer::ProfileBuffer(uint32_t aCapacity)
-    : mEntryIndexMask(0), mRangeStart(0), mRangeEnd(0), mCapacity(0) {
-  // Round aCapacity up to the nearest power of two, so that we can index
-  // mEntries with a simple mask and don't need to do a slow modulo operation.
-  const uint32_t UINT32_MAX_POWER_OF_TWO = 1 << 31;
-  MOZ_RELEASE_ASSERT(aCapacity <= UINT32_MAX_POWER_OF_TWO,
-                     "aCapacity is larger than what we support");
-  mCapacity = RoundUpPow2(aCapacity);
-  mEntryIndexMask = mCapacity - 1;
-  mEntries = MakeUnique<ProfileBufferEntry[]>(mCapacity);
+// 65536 bytes should be plenty for a single backtrace.
+static constexpr auto DuplicationBufferBytes = MakePowerOfTwo32<65536>();
+
+ProfileBuffer::ProfileBuffer(BlocksRingBuffer& aBuffer, PowerOfTwo32 aCapacity)
+    : mEntries(aBuffer),
+      mDuplicationBuffer(MakeUnique<BlocksRingBuffer::Byte[]>(
+          DuplicationBufferBytes.Value())) {
+  // Only ProfileBuffer should control this buffer, and it should be empty when
+  // there is no ProfileBuffer using it.
+  MOZ_ASSERT(mEntries.BufferLength().isNothing());
+  // Allocate the requested capacity.
+  mEntries.Set(aCapacity);
+}
+
+ProfileBuffer::ProfileBuffer(BlocksRingBuffer& aBuffer) : mEntries(aBuffer) {
+  // Assume the given buffer is not empty.
+  MOZ_ASSERT(mEntries.BufferLength().isSome());
 }
 
 ProfileBuffer::~ProfileBuffer() {
-  while (mStoredMarkers.peek()) {
-    delete mStoredMarkers.popHead();
+  // Only ProfileBuffer controls this buffer, and it should be empty when there
+  // is no ProfileBuffer using it.
+  mEntries.Reset();
+  MOZ_ASSERT(mEntries.BufferLength().isNothing());
+}
+
+/* static */
+BlocksRingBuffer::BlockIndex ProfileBuffer::AddEntry(
+    BlocksRingBuffer& aBlocksRingBuffer, const ProfileBufferEntry& aEntry) {
+  switch (aEntry.GetKind()) {
+#  define SWITCH_KIND(KIND, TYPE, SIZE)                      \
+    case ProfileBufferEntry::Kind::KIND: {                   \
+      return aBlocksRingBuffer.PutFrom(&aEntry, 1 + (SIZE)); \
+      break;                                                 \
+    }
+
+    FOR_EACH_PROFILE_BUFFER_ENTRY_KIND(SWITCH_KIND)
+
+#  undef SWITCH_KIND
+    default:
+      MOZ_ASSERT(false, "Unhandled baseprofiler::ProfilerBuffer entry KIND");
+      return BlockIndex{};
   }
 }
 
 // Called from signal, call only reentrant functions
-void ProfileBuffer::AddEntry(const ProfileBufferEntry& aEntry) {
-  GetEntry(mRangeEnd++) = aEntry;
+uint64_t ProfileBuffer::AddEntry(const ProfileBufferEntry& aEntry) {
+  return AddEntry(mEntries, aEntry).ConvertToU64();
+}
 
-  // The distance between mRangeStart and mRangeEnd must never exceed
-  // mCapacity, so advance mRangeStart if necessary.
-  if (mRangeEnd - mRangeStart > mCapacity) {
-    mRangeStart++;
-  }
+/* static */
+BlocksRingBuffer::BlockIndex ProfileBuffer::AddThreadIdEntry(
+    BlocksRingBuffer& aBlocksRingBuffer, int aThreadId) {
+  return AddEntry(aBlocksRingBuffer, ProfileBufferEntry::ThreadId(aThreadId));
 }
 
 uint64_t ProfileBuffer::AddThreadIdEntry(int aThreadId) {
-  uint64_t pos = mRangeEnd;
-  AddEntry(ProfileBufferEntry::ThreadId(aThreadId));
-  return pos;
-}
-
-void ProfileBuffer::AddStoredMarker(ProfilerMarker* aStoredMarker) {
-  aStoredMarker->SetPositionInBuffer(mRangeEnd);
-  mStoredMarkers.insert(aStoredMarker);
+  return AddThreadIdEntry(mEntries, aThreadId).ConvertToU64();
 }
 
 void ProfileBuffer::CollectCodeLocation(
@@ -92,25 +110,67 @@ void ProfileBuffer::CollectCodeLocation(
   }
 }
 
-void ProfileBuffer::DeleteExpiredStoredMarkers() {
-  // Delete markers of samples that have been overwritten due to circular
-  // buffer wraparound.
-  while (mStoredMarkers.peek() &&
-         mStoredMarkers.peek()->HasExpired(mRangeStart)) {
-    delete mStoredMarkers.popHead();
-  }
-}
-
-size_t ProfileBuffer::SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const {
-  size_t n = aMallocSizeOf(this);
-  n += aMallocSizeOf(mEntries.get());
-
+size_t ProfileBuffer::SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const {
   // Measurement of the following members may be added later if DMD finds it
   // is worthwhile:
   // - memory pointed to by the elements within mEntries
-  // - mStoredMarkers
+  return mEntries.SizeOfExcludingThis(aMallocSizeOf);
+}
 
-  return n;
+size_t ProfileBuffer::SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const {
+  return aMallocSizeOf(this) + SizeOfExcludingThis(aMallocSizeOf);
+}
+
+void ProfileBuffer::CollectOverheadStats(TimeDuration aSamplingTime,
+                                         TimeDuration aLocking,
+                                         TimeDuration aCleaning,
+                                         TimeDuration aCounters,
+                                         TimeDuration aThreads) {
+  double timeNs = aSamplingTime.ToMilliseconds() * 1000.0;
+  if (mFirstSamplingTimeNs == 0.0) {
+    mFirstSamplingTimeNs = timeNs;
+  } else {
+    // Note that we'll have 1 fewer interval than other numbers (because
+    // we need both ends of an interval to know its duration). The final
+    // difference should be insignificant over the expected many thousands
+    // of iterations.
+    mIntervalsNs.Count(timeNs - mLastSamplingTimeNs);
+  }
+  mLastSamplingTimeNs = timeNs;
+  // Time to take the lock before sampling.
+  double lockingNs = aLocking.ToMilliseconds() * 1000.0;
+  // Time to discard expired markers.
+  double cleaningNs = aCleaning.ToMilliseconds() * 1000.0;
+  // Time to gather all counters.
+  double countersNs = aCounters.ToMilliseconds() * 1000.0;
+  // Time to sample all threads.
+  double threadsNs = aThreads.ToMilliseconds() * 1000.0;
+
+  // Add to our gathered stats.
+  mOverheadsNs.Count(lockingNs + cleaningNs + countersNs + threadsNs);
+  mLockingsNs.Count(lockingNs);
+  mCleaningsNs.Count(cleaningNs);
+  mCountersNs.Count(countersNs);
+  mThreadsNs.Count(threadsNs);
+
+  // Record details in buffer.
+  AddEntry(ProfileBufferEntry::ProfilerOverheadTime(timeNs));
+  AddEntry(ProfileBufferEntry::ProfilerOverheadDuration(lockingNs));
+  AddEntry(ProfileBufferEntry::ProfilerOverheadDuration(cleaningNs));
+  AddEntry(ProfileBufferEntry::ProfilerOverheadDuration(countersNs));
+  AddEntry(ProfileBufferEntry::ProfilerOverheadDuration(threadsNs));
+}
+
+ProfilerBufferInfo ProfileBuffer::GetProfilerBufferInfo() const {
+  return {BufferRangeStart(),
+          BufferRangeEnd(),
+          mEntries.BufferLength()->Value() / 8,  // 8 bytes per entry.
+          mIntervalsNs,
+          mOverheadsNs,
+          mLockingsNs,
+          mCleaningsNs,
+          mCountersNs,
+          mThreadsNs};
 }
 
 /* ProfileBufferCollector */
diff --git a/mozglue/baseprofiler/core/ProfileBuffer.h b/mozglue/baseprofiler/core/ProfileBuffer.h
index c52db762d8..e09c978dca 100644
--- a/mozglue/baseprofiler/core/ProfileBuffer.h
+++ b/mozglue/baseprofiler/core/ProfileBuffer.h
@@ -6,37 +6,43 @@
 #define MOZ_PROFILE_BUFFER_H
 
 #include "ProfileBufferEntry.h"
-#include "ProfilerMarker.h"
 
+#include "mozilla/BlocksRingBuffer.h"
 #include "mozilla/Maybe.h"
+#include "mozilla/PowerOfTwo.h"
 
 namespace mozilla {
 namespace baseprofiler {
 
-// A fixed-capacity circular buffer.
+// Class storing most profiling data in a BlocksRingBuffer.
+//
 // This class is used as a queue of entries which, after construction, never
 // allocates. This makes it safe to use in the profiler's "critical section".
-// Entries are appended at the end. Once the queue capacity has been reached,
-// adding a new entry will evict an old entry from the start of the queue.
-// Positions in the queue are represented as 64-bit unsigned integers which
-// only increase and never wrap around.
-// mRangeStart and mRangeEnd describe the range in that uint64_t space which is
-// covered by the queue contents.
-// Internally, the buffer uses a fixed-size storage and applies a modulo
-// operation when accessing entries in that storage buffer. "Evicting" an entry
-// really just means that an existing entry in the storage buffer gets
-// overwritten and that mRangeStart gets incremented.
 class ProfileBuffer final {
  public:
+  // Opaque type containing a block index, which should not be modified outside
+  // of BlocksRingBuffer.
+  // TODO: Eventually, all uint64_t values should be replaced with BlockIndex,
+  // because external users should only store and compare them, but not do other
+  // arithmetic operations (that uint64_t supports).
+  using BlockIndex = BlocksRingBuffer::BlockIndex;
+
   // ProfileBuffer constructor
-  // @param aCapacity The minimum capacity of the buffer. The actual buffer
-  //                   capacity will be rounded up to the next power of two.
-  explicit ProfileBuffer(uint32_t aCapacity);
+  // @param aBuffer The empty BlocksRingBuffer to use as buffer manager.
+  // @param aCapacity The capacity of the buffer in memory.
+  ProfileBuffer(BlocksRingBuffer& aBuffer, PowerOfTwo32 aCapacity);
+
+  // ProfileBuffer constructor
+  // @param aBuffer The pre-filled BlocksRingBuffer to use as buffer manager.
+  explicit ProfileBuffer(BlocksRingBuffer& aBuffer);
 
   ~ProfileBuffer();
 
+  bool IsThreadSafe() const { return mEntries.IsThreadSafe(); }
+
   // Add |aEntry| to the buffer, ignoring what kind of entry it is.
-  void AddEntry(const ProfileBufferEntry& aEntry);
+  // Returns the position of the entry.
+  uint64_t AddEntry(const ProfileBufferEntry& aEntry);
 
   // Add to the buffer a sample start (ThreadId) entry for aThreadId.
   // Returns the position of the entry.
@@ -71,9 +77,6 @@ class ProfileBuffer final {
   void StreamCountersToJSON(SpliceableJSONWriter& aWriter,
                             const TimeStamp& aProcessStartTime,
                             double aSinceTime) const;
-  void StreamMemoryToJSON(SpliceableJSONWriter& aWriter,
-                          const TimeStamp& aProcessStartTime,
-                          double aSinceTime) const;
 
   // Find (via |aLastSample|) the most recent sample for the thread denoted by
   // |aThreadId| and clone it, patching in the current time as appropriate.
@@ -84,52 +87,73 @@ class ProfileBuffer final {
 
   void DiscardSamplesBeforeTime(double aTime);
 
-  void AddStoredMarker(ProfilerMarker* aStoredMarker);
-
-  // The following method is not signal safe!
-  void DeleteExpiredStoredMarkers();
-
-  // Access an entry in the buffer.
-  ProfileBufferEntry& GetEntry(uint64_t aPosition) const {
-    return mEntries[aPosition & mEntryIndexMask];
-  }
-
+  size_t SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const;
   size_t SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const;
 
- private:
-  // The storage that backs our buffer. Holds mCapacity entries.
-  // All accesses to entries in mEntries need to go through GetEntry(), which
-  // translates the given buffer position from the near-infinite uint64_t space
-  // into the entry storage space.
-  UniquePtr<ProfileBufferEntry[]> mEntries;
+  void CollectOverheadStats(TimeDuration aSamplingTime, TimeDuration aLocking,
+                            TimeDuration aCleaning, TimeDuration aCounters,
+                            TimeDuration aThreads);
 
-  // A mask such that pos & mEntryIndexMask == pos % mCapacity.
-  uint32_t mEntryIndexMask;
+  ProfilerBufferInfo GetProfilerBufferInfo() const;
+
+ private:
+  // Add |aEntry| to the provider BlocksRingBuffer.
+  // `static` because it may be used to add an entry to a `BlocksRingBuffer`
+  // that is not attached to a `ProfileBuffer`.
+  static BlockIndex AddEntry(BlocksRingBuffer& aBlocksRingBuffer,
+                             const ProfileBufferEntry& aEntry);
+
+  // Add a sample start (ThreadId) entry for aThreadId to the provided
+  // BlocksRingBuffer. Returns the position of the entry.
+  // `static` because it may be used to add an entry to a `BlocksRingBuffer`
+  // that is not attached to a `ProfileBuffer`.
+  static BlockIndex AddThreadIdEntry(BlocksRingBuffer& aBlocksRingBuffer,
+                                     int aThreadId);
+
+  // The circular-ring storage in which this ProfileBuffer stores its data.
+  BlocksRingBuffer& mEntries;
 
  public:
-  // mRangeStart and mRangeEnd are uint64_t values that strictly advance and
-  // never wrap around. mRangeEnd is always greater than or equal to
-  // mRangeStart, but never gets more than mCapacity steps ahead of
-  // mRangeStart, because we can only store a fixed number of entries in the
-  // buffer. Once the entire buffer is in use, adding a new entry will evict an
-  // entry from the front of the buffer (and increase mRangeStart).
-  // In other words, the following conditions hold true at all times:
-  //  (1) mRangeStart <= mRangeEnd
-  //  (2) mRangeEnd - mRangeStart <= mCapacity
+  // `BufferRangeStart()` and `BufferRangeEnd()` return `uint64_t` values
+  // corresponding to the first entry and past the last entry stored in
+  // `mEntries`.
   //
-  // If there are no live entries, then mRangeStart == mRangeEnd.
-  // Otherwise, mRangeStart is the first live entry and mRangeEnd is one past
-  // the last live entry, and also the position at which the next entry will be
-  // added.
-  // (mRangeEnd - mRangeStart) always gives the number of live entries.
-  uint64_t mRangeStart;
-  uint64_t mRangeEnd;
+  // The returned values are not guaranteed to be stable, because other threads
+  // may also be accessing the buffer concurrently. But they will always
+  // increase, and can therefore give an indication of how far these values have
+  // *at least* reached. In particular:
+  // - Entries whose index is strictly less that `BufferRangeStart()` have been
+  //   discarded by now, so any related data may also be safely discarded.
+  // - It is safe to try and read entries at any index strictly less than
+  //   `BufferRangeEnd()` -- but note that these reads may fail by the time you
+  //   request them, as old entries get overwritten by new ones.
+  uint64_t BufferRangeStart() const {
+    return mEntries.GetState().mRangeStart.ConvertToU64();
+  }
+  uint64_t BufferRangeEnd() const {
+    return mEntries.GetState().mRangeEnd.ConvertToU64();
+  }
 
-  // The number of entries in our buffer. Always a power of two.
-  uint32_t mCapacity;
+ private:
+  // Used when duplicating sleeping stacks (to avoid spurious mallocs).
+  const UniquePtr<BlocksRingBuffer::Byte[]> mDuplicationBuffer;
 
-  // Markers that marker entries in the buffer might refer to.
-  ProfilerMarkerLinkedList mStoredMarkers;
+  // Time from launch (ns) when first sampling was recorded.
+  double mFirstSamplingTimeNs = 0.0;
+  // Time from launch (ns) when last sampling was recorded.
+  double mLastSamplingTimeNs = 0.0;
+  // Sampling stats: Interval (ns) between successive samplings.
+  ProfilerStats mIntervalsNs;
+  // Sampling stats: Total duration (ns) of each sampling. (Split detail below.)
+  ProfilerStats mOverheadsNs;
+  // Sampling stats: Time (ns) to acquire the lock before sampling.
+  ProfilerStats mLockingsNs;
+  // Sampling stats: Time (ns) to discard expired data.
+  ProfilerStats mCleaningsNs;
+  // Sampling stats: Time (ns) to collect counter data.
+  ProfilerStats mCountersNs;
+  // Sampling stats: Time (ns) to sample thread stacks.
+  ProfilerStats mThreadsNs;
 };
 
 /**
@@ -148,7 +172,9 @@ class ProfileBufferCollector final : public ProfilerStackCollector {
     return Some(mSamplePositionInBuffer);
   }
 
-  Maybe<uint64_t> BufferRangeStart() override { return Some(mBuf.mRangeStart); }
+  Maybe<uint64_t> BufferRangeStart() override {
+    return Some(mBuf.BufferRangeStart());
+  }
 
   virtual void CollectNativeLeafAddr(void* aAddr) override;
   virtual void CollectProfilingStackFrame(
diff --git a/mozglue/baseprofiler/core/ProfileBufferEntry.cpp b/mozglue/baseprofiler/core/ProfileBufferEntry.cpp
index d13ac887e2..241f74fb19 100644
--- a/mozglue/baseprofiler/core/ProfileBufferEntry.cpp
+++ b/mozglue/baseprofiler/core/ProfileBufferEntry.cpp
@@ -8,6 +8,7 @@
 
 #  include "ProfileBufferEntry.h"
 
+#  include "BaseProfilerMarkerPayload.h"
 #  include "platform.h"
 #  include "ProfileBuffer.h"
 
@@ -41,11 +42,6 @@ ProfileBufferEntry::ProfileBufferEntry(Kind aKind, void* aPtr) : mKind(aKind) {
   memcpy(mStorage, &aPtr, sizeof(aPtr));
 }
 
-ProfileBufferEntry::ProfileBufferEntry(Kind aKind, ProfilerMarker* aMarker)
-    : mKind(aKind) {
-  memcpy(mStorage, &aMarker, sizeof(aMarker));
-}
-
 ProfileBufferEntry::ProfileBufferEntry(Kind aKind, double aDouble)
     : mKind(aKind) {
   memcpy(mStorage, &aDouble, sizeof(aDouble));
@@ -77,12 +73,6 @@ void* ProfileBufferEntry::GetPtr() const {
   return result;
 }
 
-ProfilerMarker* ProfileBufferEntry::GetMarker() const {
-  ProfilerMarker* result;
-  memcpy(&result, mStorage, sizeof(result));
-  return result;
-}
-
 double ProfileBufferEntry::GetDouble() const {
   double result;
   memcpy(&result, mStorage, sizeof(result));
@@ -270,17 +260,6 @@ uint32_t UniqueStacks::GetOrAddStackIndex(const StackKey& aStack) {
   return count;
 }
 
-template <typename RangeT, typename PosT>
-struct PositionInRangeComparator final {
-  bool Equals(const RangeT& aRange, PosT aPos) const {
-    return aRange.mRangeStart <= aPos && aPos < aRange.mRangeEnd;
-  }
-
-  bool LessThan(const RangeT& aRange, PosT aPos) const {
-    return aRange.mRangeEnd <= aPos;
-  }
-};
-
 uint32_t UniqueStacks::GetOrAddFrameIndex(const FrameKey& aFrame) {
   uint32_t count = mFrameToIndexMap.count();
   auto entry = mFrameToIndexMap.lookupForAdd(aFrame);
@@ -324,7 +303,8 @@ void UniqueStacks::StreamNonJITFrame(const FrameKey& aFrame) {
     OPTIMIZATIONS = 3,
     LINE = 4,
     COLUMN = 5,
-    CATEGORY = 6
+    CATEGORY = 6,
+    SUBCATEGORY = 7
   };
 
   AutoArraySchemaWriter writer(mFrameTableWriter, *mUniqueStrings);
@@ -342,6 +322,7 @@ void UniqueStacks::StreamNonJITFrame(const FrameKey& aFrame) {
     const ProfilingCategoryPairInfo& info =
         GetProfilingCategoryPairInfo(*data.mCategoryPair);
     writer.IntElement(CATEGORY, uint32_t(info.mCategory));
+    writer.IntElement(SUBCATEGORY, info.mSubcategoryIndex);
   }
 }
 
@@ -356,8 +337,6 @@ struct ProfileSample {
   uint32_t mStack;
   double mTime;
   Maybe<double> mResponsiveness;
-  Maybe<double> mRSS;
-  Maybe<double> mUSS;
 };
 
 static void WriteSample(SpliceableJSONWriter& aWriter,
@@ -367,8 +346,6 @@ static void WriteSample(SpliceableJSONWriter& aWriter,
     STACK = 0,
     TIME = 1,
     RESPONSIVENESS = 2,
-    RSS = 3,
-    USS = 4
   };
 
   AutoArraySchemaWriter writer(aWriter, aUniqueStrings);
@@ -380,36 +357,73 @@ static void WriteSample(SpliceableJSONWriter& aWriter,
   if (aSample.mResponsiveness.isSome()) {
     writer.DoubleElement(RESPONSIVENESS, *aSample.mResponsiveness);
   }
-
-  if (aSample.mRSS.isSome()) {
-    writer.DoubleElement(RSS, *aSample.mRSS);
-  }
-
-  if (aSample.mUSS.isSome()) {
-    writer.DoubleElement(USS, *aSample.mUSS);
-  }
 }
 
 class EntryGetter {
  public:
-  explicit EntryGetter(const ProfileBuffer& aBuffer,
+  explicit EntryGetter(BlocksRingBuffer::Reader& aReader,
                        uint64_t aInitialReadPos = 0)
-      : mBuffer(aBuffer), mReadPos(aBuffer.mRangeStart) {
-    if (aInitialReadPos != 0) {
-      MOZ_RELEASE_ASSERT(aInitialReadPos >= aBuffer.mRangeStart &&
-                         aInitialReadPos <= aBuffer.mRangeEnd);
-      mReadPos = aInitialReadPos;
+      : mBlockIt(aReader.At(
+            BlocksRingBuffer::BlockIndex::ConvertFromU64(aInitialReadPos))),
+        mBlockItEnd(aReader.end()) {
+    if (!ReadLegacyOrEnd()) {
+      // Find and read the next non-legacy entry.
+      Next();
     }
   }
 
-  bool Has() const { return mReadPos != mBuffer.mRangeEnd; }
-  const ProfileBufferEntry& Get() const { return mBuffer.GetEntry(mReadPos); }
-  void Next() { mReadPos++; }
-  uint64_t CurPos() { return mReadPos; }
+  bool Has() const { return mBlockIt != mBlockItEnd; }
+
+  const ProfileBufferEntry& Get() const {
+    MOZ_ASSERT(Has(), "Caller should have checked `Has()` before `Get()`");
+    return mEntry;
+  }
+
+  void Next() {
+    MOZ_ASSERT(Has(), "Caller should have checked `Has()` before `Next()`");
+    for (;;) {
+      ++mBlockIt;
+      if (ReadLegacyOrEnd()) {
+        // Either we're at the end, or we could read a legacy entry -> Done.
+        break;
+      }
+      // Otherwise loop around until we hit the end or a legacy entry.
+    }
+  }
+
+  ProfileBuffer::BlockIndex CurBlockIndex() const {
+    return mBlockIt.CurrentBlockIndex();
+  }
+
+  uint64_t CurPos() const { return CurBlockIndex().ConvertToU64(); }
 
  private:
-  const ProfileBuffer& mBuffer;
-  uint64_t mReadPos;
+  // Try to read the entry at the current `mBlockIt` position.
+  // * If we're at the end of the buffer, just return `true`.
+  // * If there is a "legacy" entry (containing a real `ProfileBufferEntry`),
+  //   read it into `mEntry`, and return `true` as well.
+  // * Otherwise the entry contains a "modern" type that cannot be read into
+  // `mEntry`, return `false` (so `EntryGetter` can skip to another entry).
+  bool ReadLegacyOrEnd() {
+    if (!Has()) {
+      return true;
+    }
+    BlocksRingBuffer::EntryReader aER = *mBlockIt;
+    auto type = static_cast<ProfileBufferEntry::Kind>(
+        aER.PeekObject<ProfileBufferEntry::KindUnderlyingType>());
+    MOZ_ASSERT(static_cast<ProfileBufferEntry::KindUnderlyingType>(type) <
+               static_cast<ProfileBufferEntry::KindUnderlyingType>(
+                   ProfileBufferEntry::Kind::MODERN_LIMIT));
+    if (type >= ProfileBufferEntry::Kind::LEGACY_LIMIT) {
+      return false;
+    }
+    aER.Read(&mEntry, aER.RemainingBytes());
+    return true;
+  }
+
+  ProfileBufferEntry mEntry;
+  BlocksRingBuffer::BlockIterator mBlockIt;
+  const BlocksRingBuffer::BlockIterator mBlockItEnd;
 };
 
 // The following grammar shows legal sequences of profile buffer entries.
@@ -425,10 +439,7 @@ class EntryGetter {
 //     )+
 //     Marker*
 //     Responsiveness?
-//     ResidentMemory?
-//     UnsharedMemory?
 //   )
-//   | ( ResidentMemory UnsharedMemory? Time)  /* Memory */
 //   | ( /* Counters */
 //       CounterId
 //       Time
@@ -559,232 +570,220 @@ void ProfileBuffer::StreamSamplesToJSON(SpliceableJSONWriter& aWriter,
                                         UniqueStacks& aUniqueStacks) const {
   UniquePtr<char[]> dynStrBuf = MakeUnique<char[]>(kMaxFrameKeyLength);
 
-  EntryGetter e(*this);
+  mEntries.Read([&](BlocksRingBuffer::Reader* aReader) {
+    MOZ_ASSERT(
+        aReader,
+        "BlocksRingBuffer cannot be out-of-session when sampler is running");
+
+    EntryGetter e(*aReader);
+
+    for (;;) {
+      // This block skips entries until we find the start of the next sample.
+      // This is useful in three situations.
+      //
+      // - The circular buffer overwrites old entries, so when we start parsing
+      //   we might be in the middle of a sample, and we must skip forward to
+      //   the start of the next sample.
+      //
+      // - We skip samples that don't have an appropriate ThreadId or Time.
+      //
+      // - We skip range Pause, Resume, CollectionStart, Marker, Counter
+      //   and CollectionEnd entries between samples.
+      while (e.Has()) {
+        if (e.Get().IsThreadId()) {
+          break;
+        }
+        e.Next();
+      }
+
+      if (!e.Has()) {
+        break;
+      }
 
-  for (;;) {
-    // This block skips entries until we find the start of the next sample.
-    // This is useful in three situations.
-    //
-    // - The circular buffer overwrites old entries, so when we start parsing
-    //   we might be in the middle of a sample, and we must skip forward to the
-    //   start of the next sample.
-    //
-    // - We skip samples that don't have an appropriate ThreadId or Time.
-    //
-    // - We skip range Pause, Resume, CollectionStart, Marker, Counter
-    //   and CollectionEnd entries between samples.
-    while (e.Has()) {
       if (e.Get().IsThreadId()) {
-        break;
+        int threadId = e.Get().GetInt();
+        e.Next();
+
+        // Ignore samples that are for the wrong thread.
+        if (threadId != aThreadId) {
+          continue;
+        }
       } else {
-        e.Next();
+        // Due to the skip_to_next_sample block above, if we have an entry here
+        // it must be a ThreadId entry.
+        MOZ_CRASH();
       }
-    }
 
-    if (!e.Has()) {
-      break;
-    }
+      ProfileSample sample;
 
-    if (e.Get().IsThreadId()) {
-      int threadId = e.Get().GetInt();
-      e.Next();
-
-      // Ignore samples that are for the wrong thread.
-      if (threadId != aThreadId) {
-        continue;
-      }
-    } else {
-      // Due to the skip_to_next_sample block above, if we have an entry here
-      // it must be a ThreadId entry.
-      MOZ_CRASH();
-    }
-
-    ProfileSample sample;
-
-    if (e.Has() && e.Get().IsTime()) {
-      sample.mTime = e.Get().GetDouble();
-      e.Next();
-
-      // Ignore samples that are too old.
-      if (sample.mTime < aSinceTime) {
-        continue;
-      }
-    } else {
-      ERROR_AND_CONTINUE("expected a Time entry");
-    }
-
-    UniqueStacks::StackKey stack =
-        aUniqueStacks.BeginStack(UniqueStacks::FrameKey("(root)"));
-
-    int numFrames = 0;
-    while (e.Has()) {
-      if (e.Get().IsNativeLeafAddr()) {
-        numFrames++;
-
-        void* pc = e.Get().GetPtr();
+      if (e.Has() && e.Get().IsTime()) {
+        sample.mTime = e.Get().GetDouble();
         e.Next();
 
-        static const uint32_t BUF_SIZE = 256;
-        char buf[BUF_SIZE];
-
-        // Bug 753041: We need a double cast here to tell GCC that we don't
-        // want to sign extend 32-bit addresses starting with 0xFXXXXXX.
-        unsigned long long pcULL = (unsigned long long)(uintptr_t)pc;
-        SprintfLiteral(buf, "%#llx", pcULL);
-
-        // If the "MOZ_BASE_PROFILER_SYMBOLICATE" env-var is set, we add a local
-        // symbolication description to the PC address. This is off by default,
-        // and mainly intended for local development.
-        static const bool preSymbolicate = []() {
-          const char* symbolicate = getenv("MOZ_BASE_PROFILER_SYMBOLICATE");
-          return symbolicate && symbolicate[0] != '\0';
-        }();
-        if (preSymbolicate) {
-          MozCodeAddressDetails details;
-          if (MozDescribeCodeAddress(pc, &details)) {
-            // Replace \0 terminator with space.
-            const uint32_t pcLen = strlen(buf);
-            buf[pcLen] = ' ';
-            // Add description after space. Note: Using a frame number of 0,
-            // as using `numFrames` wouldn't help here, and would prevent
-            // combining same function calls that happen at different depths.
-            // TODO: Remove unsightly "#00: " if too annoying. :-)
-            MozFormatCodeAddressDetails(buf + pcLen + 1, BUF_SIZE - (pcLen + 1),
-                                        0, pc, &details);
-          }
+        // Ignore samples that are too old.
+        if (sample.mTime < aSinceTime) {
+          continue;
         }
+      } else {
+        ERROR_AND_CONTINUE("expected a Time entry");
+      }
 
-        stack = aUniqueStacks.AppendFrame(stack, UniqueStacks::FrameKey(buf));
+      UniqueStacks::StackKey stack =
+          aUniqueStacks.BeginStack(UniqueStacks::FrameKey("(root)"));
 
-      } else if (e.Get().IsLabel()) {
-        numFrames++;
+      int numFrames = 0;
+      while (e.Has()) {
+        if (e.Get().IsNativeLeafAddr()) {
+          numFrames++;
 
-        const char* label = e.Get().GetString();
-        e.Next();
-
-        using FrameFlags = ProfilingStackFrame::Flags;
-        uint32_t frameFlags = 0;
-        if (e.Has() && e.Get().IsFrameFlags()) {
-          frameFlags = uint32_t(e.Get().GetUint64());
+          void* pc = e.Get().GetPtr();
           e.Next();
-        }
 
-        bool relevantForJS = frameFlags & uint32_t(FrameFlags::RELEVANT_FOR_JS);
+          static const uint32_t BUF_SIZE = 256;
+          char buf[BUF_SIZE];
 
-        // Copy potential dynamic string fragments into dynStrBuf, so that
-        // dynStrBuf will then contain the entire dynamic string.
-        size_t i = 0;
-        dynStrBuf[0] = '\0';
-        while (e.Has()) {
-          if (e.Get().IsDynamicStringFragment()) {
-            char chars[ProfileBufferEntry::kNumChars];
-            e.Get().CopyCharsInto(chars);
-            for (char c : chars) {
-              if (i < kMaxFrameKeyLength) {
-                dynStrBuf[i] = c;
-                i++;
-              }
+          // Bug 753041: We need a double cast here to tell GCC that we don't
+          // want to sign extend 32-bit addresses starting with 0xFXXXXXX.
+          unsigned long long pcULL = (unsigned long long)(uintptr_t)pc;
+          SprintfLiteral(buf, "%#llx", pcULL);
+
+          // If the "MOZ_BASE_PROFILER_SYMBOLICATE" env-var is set, we add a
+          // local symbolication description to the PC address. This is off by
+          // default, and mainly intended for local development.
+          static const bool preSymbolicate = []() {
+            const char* symbolicate = getenv("MOZ_BASE_PROFILER_SYMBOLICATE");
+            return symbolicate && symbolicate[0] != '\0';
+          }();
+          if (preSymbolicate) {
+            MozCodeAddressDetails details;
+            if (MozDescribeCodeAddress(pc, &details)) {
+              // Replace \0 terminator with space.
+              const uint32_t pcLen = strlen(buf);
+              buf[pcLen] = ' ';
+              // Add description after space. Note: Using a frame number of 0,
+              // as using `numFrames` wouldn't help here, and would prevent
+              // combining same function calls that happen at different depths.
+              // TODO: Remove unsightly "#00: " if too annoying. :-)
+              MozFormatCodeAddressDetails(
+                  buf + pcLen + 1, BUF_SIZE - (pcLen + 1), 0, pc, &details);
             }
+          }
+
+          stack = aUniqueStacks.AppendFrame(stack, UniqueStacks::FrameKey(buf));
+
+        } else if (e.Get().IsLabel()) {
+          numFrames++;
+
+          const char* label = e.Get().GetString();
+          e.Next();
+
+          using FrameFlags = ProfilingStackFrame::Flags;
+          uint32_t frameFlags = 0;
+          if (e.Has() && e.Get().IsFrameFlags()) {
+            frameFlags = uint32_t(e.Get().GetUint64());
             e.Next();
-          } else {
-            break;
           }
-        }
-        dynStrBuf[kMaxFrameKeyLength - 1] = '\0';
-        bool hasDynamicString = (i != 0);
 
-        std::string frameLabel;
-        if (label[0] != '\0' && hasDynamicString) {
-          if (frameFlags & uint32_t(FrameFlags::STRING_TEMPLATE_METHOD)) {
-            frameLabel += label;
-            frameLabel += '.';
-            frameLabel += dynStrBuf.get();
-          } else if (frameFlags &
-                     uint32_t(FrameFlags::STRING_TEMPLATE_GETTER)) {
-            frameLabel += "get ";
-            frameLabel += label;
-            frameLabel += '.';
-            frameLabel += dynStrBuf.get();
-          } else if (frameFlags &
-                     uint32_t(FrameFlags::STRING_TEMPLATE_SETTER)) {
-            frameLabel += "set ";
-            frameLabel += label;
-            frameLabel += '.';
+          bool relevantForJS =
+              frameFlags & uint32_t(FrameFlags::RELEVANT_FOR_JS);
+
+          // Copy potential dynamic string fragments into dynStrBuf, so that
+          // dynStrBuf will then contain the entire dynamic string.
+          size_t i = 0;
+          dynStrBuf[0] = '\0';
+          while (e.Has()) {
+            if (e.Get().IsDynamicStringFragment()) {
+              char chars[ProfileBufferEntry::kNumChars];
+              e.Get().CopyCharsInto(chars);
+              for (char c : chars) {
+                if (i < kMaxFrameKeyLength) {
+                  dynStrBuf[i] = c;
+                  i++;
+                }
+              }
+              e.Next();
+            } else {
+              break;
+            }
+          }
+          dynStrBuf[kMaxFrameKeyLength - 1] = '\0';
+          bool hasDynamicString = (i != 0);
+
+          std::string frameLabel;
+          if (label[0] != '\0' && hasDynamicString) {
+            if (frameFlags & uint32_t(FrameFlags::STRING_TEMPLATE_METHOD)) {
+              frameLabel += label;
+              frameLabel += '.';
+              frameLabel += dynStrBuf.get();
+            } else if (frameFlags &
+                       uint32_t(FrameFlags::STRING_TEMPLATE_GETTER)) {
+              frameLabel += "get ";
+              frameLabel += label;
+              frameLabel += '.';
+              frameLabel += dynStrBuf.get();
+            } else if (frameFlags &
+                       uint32_t(FrameFlags::STRING_TEMPLATE_SETTER)) {
+              frameLabel += "set ";
+              frameLabel += label;
+              frameLabel += '.';
+              frameLabel += dynStrBuf.get();
+            } else {
+              frameLabel += label;
+              frameLabel += ' ';
+              frameLabel += dynStrBuf.get();
+            }
+          } else if (hasDynamicString) {
             frameLabel += dynStrBuf.get();
           } else {
             frameLabel += label;
-            frameLabel += ' ';
-            frameLabel += dynStrBuf.get();
           }
-        } else if (hasDynamicString) {
-          frameLabel += dynStrBuf.get();
+
+          Maybe<unsigned> line;
+          if (e.Has() && e.Get().IsLineNumber()) {
+            line = Some(unsigned(e.Get().GetInt()));
+            e.Next();
+          }
+
+          Maybe<unsigned> column;
+          if (e.Has() && e.Get().IsColumnNumber()) {
+            column = Some(unsigned(e.Get().GetInt()));
+            e.Next();
+          }
+
+          Maybe<ProfilingCategoryPair> categoryPair;
+          if (e.Has() && e.Get().IsCategoryPair()) {
+            categoryPair =
+                Some(ProfilingCategoryPair(uint32_t(e.Get().GetInt())));
+            e.Next();
+          }
+
+          stack = aUniqueStacks.AppendFrame(
+              stack,
+              UniqueStacks::FrameKey(std::move(frameLabel), relevantForJS, line,
+                                     column, categoryPair));
+
         } else {
-          frameLabel += label;
+          break;
         }
-
-        Maybe<unsigned> line;
-        if (e.Has() && e.Get().IsLineNumber()) {
-          line = Some(unsigned(e.Get().GetInt()));
-          e.Next();
-        }
-
-        Maybe<unsigned> column;
-        if (e.Has() && e.Get().IsColumnNumber()) {
-          column = Some(unsigned(e.Get().GetInt()));
-          e.Next();
-        }
-
-        Maybe<ProfilingCategoryPair> categoryPair;
-        if (e.Has() && e.Get().IsCategoryPair()) {
-          categoryPair =
-              Some(ProfilingCategoryPair(uint32_t(e.Get().GetInt())));
-          e.Next();
-        }
-
-        stack = aUniqueStacks.AppendFrame(
-            stack, UniqueStacks::FrameKey(std::move(frameLabel), relevantForJS,
-                                          line, column, categoryPair));
-
-      } else {
-        break;
       }
-    }
 
-    if (numFrames == 0) {
-      // It is possible to have empty stacks if native stackwalking is
-      // disabled. Skip samples with empty stacks. (See Bug 1497985).
-      // Thus, don't use ERROR_AND_CONTINUE, but just continue.
-      continue;
-    }
+      if (numFrames == 0) {
+        // It is possible to have empty stacks if native stackwalking is
+        // disabled. Skip samples with empty stacks. (See Bug 1497985).
+        // Thus, don't use ERROR_AND_CONTINUE, but just continue.
+        continue;
+      }
 
-    sample.mStack = aUniqueStacks.GetOrAddStackIndex(stack);
+      sample.mStack = aUniqueStacks.GetOrAddStackIndex(stack);
 
-    // Skip over the markers. We process them in StreamMarkersToJSON().
-    while (e.Has()) {
-      if (e.Get().IsMarker()) {
+      if (e.Has() && e.Get().IsResponsiveness()) {
+        sample.mResponsiveness = Some(e.Get().GetDouble());
         e.Next();
-      } else {
-        break;
       }
-    }
 
-    if (e.Has() && e.Get().IsResponsiveness()) {
-      sample.mResponsiveness = Some(e.Get().GetDouble());
-      e.Next();
+      WriteSample(aWriter, *aUniqueStacks.mUniqueStrings, sample);
     }
-
-    if (e.Has() && e.Get().IsResidentMemory()) {
-      sample.mRSS = Some(e.Get().GetDouble());
-      e.Next();
-    }
-
-    if (e.Has() && e.Get().IsUnsharedMemory()) {
-      sample.mUSS = Some(e.Get().GetDouble());
-      e.Next();
-    }
-
-    WriteSample(aWriter, *aUniqueStacks.mUniqueStrings, sample);
-  }
+  });
 }
 
 void ProfileBuffer::StreamMarkersToJSON(SpliceableJSONWriter& aWriter,
@@ -792,156 +791,162 @@ void ProfileBuffer::StreamMarkersToJSON(SpliceableJSONWriter& aWriter,
                                         const TimeStamp& aProcessStartTime,
                                         double aSinceTime,
                                         UniqueStacks& aUniqueStacks) const {
-  EntryGetter e(*this);
+  mEntries.ReadEach([&](BlocksRingBuffer::EntryReader& aER) {
+    auto type = static_cast<ProfileBufferEntry::Kind>(
+        aER.ReadObject<ProfileBufferEntry::KindUnderlyingType>());
+    MOZ_ASSERT(static_cast<ProfileBufferEntry::KindUnderlyingType>(type) <
+               static_cast<ProfileBufferEntry::KindUnderlyingType>(
+                   ProfileBufferEntry::Kind::MODERN_LIMIT));
+    if (type == ProfileBufferEntry::Kind::MarkerData &&
+        aER.ReadObject<int>() == aThreadId) {
+      // Schema:
+      //   [name, time, category, data]
 
-  // Stream all markers whose threadId matches aThreadId. We skip other entries,
-  // because we process them in StreamSamplesToJSON().
-  //
-  // NOTE: The ThreadId of a marker is determined by its GetThreadId() method,
-  // rather than ThreadId buffer entries, as markers can be added outside of
-  // samples.
-  while (e.Has()) {
-    if (e.Get().IsMarker()) {
-      const ProfilerMarker* marker = e.Get().GetMarker();
-      if (marker->GetTime() >= aSinceTime &&
-          marker->GetThreadId() == aThreadId) {
-        marker->StreamJSON(aWriter, aProcessStartTime, aUniqueStacks);
+      aWriter.StartArrayElement();
+      {
+        std::string name = aER.ReadObject<std::string>();
+        const ProfilingCategoryPairInfo& info = GetProfilingCategoryPairInfo(
+            static_cast<ProfilingCategoryPair>(aER.ReadObject<uint32_t>()));
+        auto payload = aER.ReadObject<UniquePtr<ProfilerMarkerPayload>>();
+        double time = aER.ReadObject<double>();
+        MOZ_ASSERT(aER.IndexInEntry() == aER.EntryBytes());
+
+        aUniqueStacks.mUniqueStrings->WriteElement(aWriter, name.c_str());
+        aWriter.DoubleElement(time);
+        aWriter.IntElement(unsigned(info.mCategory));
+        if (payload) {
+          aWriter.StartObjectElement(SpliceableJSONWriter::SingleLineStyle);
+          { payload->StreamPayload(aWriter, aProcessStartTime, aUniqueStacks); }
+          aWriter.EndObject();
+        }
       }
+      aWriter.EndArray();
     }
-    e.Next();
-  }
+  });
 }
 
 void ProfileBuffer::StreamProfilerOverheadToJSON(
     SpliceableJSONWriter& aWriter, const TimeStamp& aProcessStartTime,
     double aSinceTime) const {
-  enum Schema : uint32_t {
-    TIME = 0,
-    LOCKING = 1,
-    MARKER_CLEANING = 2,
-    COUNTERS = 3,
-    THREADS = 4
-  };
+  mEntries.Read([&](BlocksRingBuffer::Reader* aReader) {
+    MOZ_ASSERT(
+        aReader,
+        "BlocksRingBuffer cannot be out-of-session when sampler is running");
 
-  EntryGetter e(*this);
+    EntryGetter e(*aReader);
 
-  aWriter.StartObjectProperty("profilerOverhead_UNSTABLE");
-  // Stream all sampling overhead data. We skip other entries, because we
-  // process them in StreamSamplesToJSON()/etc.
-  {
-    JSONSchemaWriter schema(aWriter);
-    schema.WriteField("time");
-    schema.WriteField("locking");
-    schema.WriteField("expiredMarkerCleaning");
-    schema.WriteField("counters");
-    schema.WriteField("threads");
-  }
+    enum Schema : uint32_t {
+      TIME = 0,
+      LOCKING = 1,
+      MARKER_CLEANING = 2,
+      COUNTERS = 3,
+      THREADS = 4
+    };
 
-  aWriter.StartArrayProperty("data");
-  double firstTime = 0.0;
-  double lastTime = 0.0;
-  struct Stats {
-    unsigned n = 0;
-    double sum = 0;
-    double min = std::numeric_limits<double>::max();
-    double max = 0;
-    void Count(double v) {
-      ++n;
-      sum += v;
-      if (v < min) {
-        min = v;
-      }
-      if (v > max) {
-        max = v;
-      }
+    aWriter.StartObjectProperty("profilerOverhead");
+    aWriter.StartObjectProperty("samples");
+    // Stream all sampling overhead data. We skip other entries, because we
+    // process them in StreamSamplesToJSON()/etc.
+    {
+      JSONSchemaWriter schema(aWriter);
+      schema.WriteField("time");
+      schema.WriteField("locking");
+      schema.WriteField("expiredMarkerCleaning");
+      schema.WriteField("counters");
+      schema.WriteField("threads");
     }
-  };
-  Stats intervals, overheads, lockings, cleanings, counters, threads;
-  while (e.Has()) {
-    // valid sequence: ProfilerOverheadTime, ProfilerOverheadDuration * 4
-    if (e.Get().IsProfilerOverheadTime()) {
-      double time = e.Get().GetDouble();
-      if (time >= aSinceTime) {
-        e.Next();
-        if (!e.Has() || !e.Get().IsProfilerOverheadDuration()) {
-          ERROR_AND_CONTINUE(
-              "expected a ProfilerOverheadDuration entry after "
-              "ProfilerOverheadTime");
-        }
-        double locking = e.Get().GetDouble();
-        e.Next();
-        if (!e.Has() || !e.Get().IsProfilerOverheadDuration()) {
-          ERROR_AND_CONTINUE(
-              "expected a ProfilerOverheadDuration entry after "
-              "ProfilerOverheadTime,ProfilerOverheadDuration");
-        }
-        double cleaning = e.Get().GetDouble();
-        e.Next();
-        if (!e.Has() || !e.Get().IsProfilerOverheadDuration()) {
-          ERROR_AND_CONTINUE(
-              "expected a ProfilerOverheadDuration entry after "
-              "ProfilerOverheadTime,ProfilerOverheadDuration*2");
-        }
-        double counter = e.Get().GetDouble();
-        e.Next();
-        if (!e.Has() || !e.Get().IsProfilerOverheadDuration()) {
-          ERROR_AND_CONTINUE(
-              "expected a ProfilerOverheadDuration entry after "
-              "ProfilerOverheadTime,ProfilerOverheadDuration*3");
-        }
-        double thread = e.Get().GetDouble();
 
-        if (firstTime == 0.0) {
-          firstTime = time;
-        } else {
-          // Note that we'll have 1 fewer interval than other numbers (because
-          // we need both ends of an interval to know its duration). The final
-          // difference should be insignificant over the expected many thousands
-          // of iterations.
-          intervals.Count(time - lastTime);
-        }
-        lastTime = time;
-        overheads.Count(locking + cleaning + counter + thread);
-        lockings.Count(locking);
-        cleanings.Count(cleaning);
-        counters.Count(counter);
-        threads.Count(thread);
+    aWriter.StartArrayProperty("data");
+    double firstTime = 0.0;
+    double lastTime = 0.0;
+    ProfilerStats intervals, overheads, lockings, cleanings, counters, threads;
+    while (e.Has()) {
+      // valid sequence: ProfilerOverheadTime, ProfilerOverheadDuration * 4
+      if (e.Get().IsProfilerOverheadTime()) {
+        double time = e.Get().GetDouble();
+        if (time >= aSinceTime) {
+          e.Next();
+          if (!e.Has() || !e.Get().IsProfilerOverheadDuration()) {
+            ERROR_AND_CONTINUE(
+                "expected a ProfilerOverheadDuration entry after "
+                "ProfilerOverheadTime");
+          }
+          double locking = e.Get().GetDouble();
+          e.Next();
+          if (!e.Has() || !e.Get().IsProfilerOverheadDuration()) {
+            ERROR_AND_CONTINUE(
+                "expected a ProfilerOverheadDuration entry after "
+                "ProfilerOverheadTime,ProfilerOverheadDuration");
+          }
+          double cleaning = e.Get().GetDouble();
+          e.Next();
+          if (!e.Has() || !e.Get().IsProfilerOverheadDuration()) {
+            ERROR_AND_CONTINUE(
+                "expected a ProfilerOverheadDuration entry after "
+                "ProfilerOverheadTime,ProfilerOverheadDuration*2");
+          }
+          double counter = e.Get().GetDouble();
+          e.Next();
+          if (!e.Has() || !e.Get().IsProfilerOverheadDuration()) {
+            ERROR_AND_CONTINUE(
+                "expected a ProfilerOverheadDuration entry after "
+                "ProfilerOverheadTime,ProfilerOverheadDuration*3");
+          }
+          double thread = e.Get().GetDouble();
 
-        AutoArraySchemaWriter writer(aWriter);
-        writer.DoubleElement(TIME, time);
-        writer.DoubleElement(LOCKING, locking);
-        writer.DoubleElement(MARKER_CLEANING, cleaning);
-        writer.DoubleElement(COUNTERS, counter);
-        writer.DoubleElement(THREADS, thread);
+          if (firstTime == 0.0) {
+            firstTime = time;
+          } else {
+            // Note that we'll have 1 fewer interval than other numbers (because
+            // we need both ends of an interval to know its duration). The final
+            // difference should be insignificant over the expected many
+            // thousands of iterations.
+            intervals.Count(time - lastTime);
+          }
+          lastTime = time;
+          overheads.Count(locking + cleaning + counter + thread);
+          lockings.Count(locking);
+          cleanings.Count(cleaning);
+          counters.Count(counter);
+          threads.Count(thread);
+
+          AutoArraySchemaWriter writer(aWriter);
+          writer.DoubleElement(TIME, time);
+          writer.DoubleElement(LOCKING, locking);
+          writer.DoubleElement(MARKER_CLEANING, cleaning);
+          writer.DoubleElement(COUNTERS, counter);
+          writer.DoubleElement(THREADS, thread);
+        }
       }
+      e.Next();
     }
-    e.Next();
-  }
-  aWriter.EndArray();  // data
+    aWriter.EndArray();   // data
+    aWriter.EndObject();  // samples
 
-  // Only output statistics if there is at least one full interval (and
-  // therefore at least two samplings.)
-  if (intervals.n > 0) {
-    aWriter.StartObjectProperty("statistics");
-    aWriter.DoubleProperty("profiledDuration", lastTime - firstTime);
-    aWriter.IntProperty("samplingCount", overheads.n);
-    aWriter.DoubleProperty("overheadDurations", overheads.sum);
-    aWriter.DoubleProperty("overheadPercentage",
-                           overheads.sum / (lastTime - firstTime));
+    // Only output statistics if there is at least one full interval (and
+    // therefore at least two samplings.)
+    if (intervals.n > 0) {
+      aWriter.StartObjectProperty("statistics");
+      aWriter.DoubleProperty("profiledDuration", lastTime - firstTime);
+      aWriter.IntProperty("samplingCount", overheads.n);
+      aWriter.DoubleProperty("overheadDurations", overheads.sum);
+      aWriter.DoubleProperty("overheadPercentage",
+                             overheads.sum / (lastTime - firstTime));
 #  define PROFILER_STATS(name, var)                           \
     aWriter.DoubleProperty("mean" name, (var).sum / (var).n); \
     aWriter.DoubleProperty("min" name, (var).min);            \
     aWriter.DoubleProperty("max" name, (var).max);
-    PROFILER_STATS("Interval", intervals);
-    PROFILER_STATS("Overhead", overheads);
-    PROFILER_STATS("Lockings", lockings);
-    PROFILER_STATS("Cleaning", cleanings);
-    PROFILER_STATS("Counter", counters);
-    PROFILER_STATS("Thread", threads);
+      PROFILER_STATS("Interval", intervals);
+      PROFILER_STATS("Overhead", overheads);
+      PROFILER_STATS("Lockings", lockings);
+      PROFILER_STATS("Cleaning", cleanings);
+      PROFILER_STATS("Counter", counters);
+      PROFILER_STATS("Thread", threads);
 #  undef PROFILER_STATS
-    aWriter.EndObject();  // statistics
-  }
-  aWriter.EndObject();  // profilerOverhead
+      aWriter.EndObject();  // statistics
+    }
+    aWriter.EndObject();  // profilerOverhead
+  });
 }
 
 struct CounterKeyedSample {
@@ -974,208 +979,155 @@ void ProfileBuffer::StreamCountersToJSON(SpliceableJSONWriter& aWriter,
   // error indicates a bug in the ProfileBuffer writing or the parser itself,
   // or possibly flaky hardware.
 
-  EntryGetter e(*this);
-  enum Schema : uint32_t { TIME = 0, NUMBER = 1, COUNT = 2 };
+  mEntries.Read([&](BlocksRingBuffer::Reader* aReader) {
+    MOZ_ASSERT(
+        aReader,
+        "BlocksRingBuffer cannot be out-of-session when sampler is running");
 
-  // Stream all counters. We skip other entries, because we process them in
-  // StreamSamplesToJSON()/etc.
-  //
-  // Valid sequence in the buffer:
-  // CounterID
-  // Time
-  // ( CounterKey Count Number? )*
-  //
-  // And the JSON (example):
-  // "counters": {
-  //  "name": "malloc",
-  //  "category": "Memory",
-  //  "description": "Amount of allocated memory",
-  //  "sample_groups": {
-  //   "id": 0,
-  //   "samples": {
-  //    "schema": {"time": 0, "number": 1, "count": 2},
-  //    "data": [
-  //     [
-  //      16117.033968000002,
-  //      2446216,
-  //      6801320
-  //     ],
-  //     [
-  //      16118.037638,
-  //      2446216,
-  //      6801320
-  //     ],
-  //    ],
-  //   }
-  //  }
-  // },
+    EntryGetter e(*aReader);
 
-  // Build the map of counters and populate it
-  HashMap<void*, CounterMap> counters;
+    enum Schema : uint32_t { TIME = 0, NUMBER = 1, COUNT = 2 };
 
-  while (e.Has()) {
-    // skip all non-Counters, including if we start in the middle of a counter
-    if (e.Get().IsCounterId()) {
-      void* id = e.Get().GetPtr();
-      CounterMap& counter = LookupOrAdd(counters, id);
-      e.Next();
-      if (!e.Has() || !e.Get().IsTime()) {
-        ERROR_AND_CONTINUE("expected a Time entry");
-      }
-      double time = e.Get().GetDouble();
-      if (time >= aSinceTime) {
+    // Stream all counters. We skip other entries, because we process them in
+    // StreamSamplesToJSON()/etc.
+    //
+    // Valid sequence in the buffer:
+    // CounterID
+    // Time
+    // ( CounterKey Count Number? )*
+    //
+    // And the JSON (example):
+    // "counters": {
+    //  "name": "malloc",
+    //  "category": "Memory",
+    //  "description": "Amount of allocated memory",
+    //  "sample_groups": {
+    //   "id": 0,
+    //   "samples": {
+    //    "schema": {"time": 0, "number": 1, "count": 2},
+    //    "data": [
+    //     [
+    //      16117.033968000002,
+    //      2446216,
+    //      6801320
+    //     ],
+    //     [
+    //      16118.037638,
+    //      2446216,
+    //      6801320
+    //     ],
+    //    ],
+    //   }
+    //  }
+    // },
+
+    // Build the map of counters and populate it
+    HashMap<void*, CounterMap> counters;
+
+    while (e.Has()) {
+      // skip all non-Counters, including if we start in the middle of a counter
+      if (e.Get().IsCounterId()) {
+        void* id = e.Get().GetPtr();
+        CounterMap& counter = LookupOrAdd(counters, id);
         e.Next();
-        while (e.Has() && e.Get().IsCounterKey()) {
-          uint64_t key = e.Get().GetUint64();
-          CounterKeyedSamples& data = LookupOrAdd(counter, key);
-          e.Next();
-          if (!e.Has() || !e.Get().IsCount()) {
-            ERROR_AND_CONTINUE("expected a Count entry");
-          }
-          int64_t count = e.Get().GetUint64();
-          e.Next();
-          uint64_t number;
-          if (!e.Has() || !e.Get().IsNumber()) {
-            number = 0;
-          } else {
-            number = e.Get().GetInt64();
-          }
-          CounterKeyedSample sample = {time, number, count};
-          MOZ_RELEASE_ASSERT(data.append(sample));
-        }
-      } else {
-        // skip counter sample - only need to skip the initial counter
-        // id, then let the loop at the top skip the rest
-      }
-    }
-    e.Next();
-  }
-  // we have a map of a map of counter entries; dump them to JSON
-  if (counters.count() == 0) {
-    return;
-  }
-
-  aWriter.StartArrayProperty("counters");
-  for (auto iter = counters.iter(); !iter.done(); iter.next()) {
-    CounterMap& counter = iter.get().value();
-    const BaseProfilerCount* base_counter =
-        static_cast<const BaseProfilerCount*>(iter.get().key());
-
-    aWriter.Start();
-    aWriter.StringProperty("name", base_counter->mLabel);
-    aWriter.StringProperty("category", base_counter->mCategory);
-    aWriter.StringProperty("description", base_counter->mDescription);
-
-    aWriter.StartObjectProperty("sample_groups");
-    for (auto counter_iter = counter.iter(); !counter_iter.done();
-         counter_iter.next()) {
-      CounterKeyedSamples& samples = counter_iter.get().value();
-      uint64_t key = counter_iter.get().key();
-
-      size_t size = samples.length();
-      if (size == 0) {
-        continue;
-      }
-      aWriter.IntProperty("id", static_cast<int64_t>(key));
-      aWriter.StartObjectProperty("samples");
-      {
-        // XXX Can we assume a missing count means 0?
-        JSONSchemaWriter schema(aWriter);
-        schema.WriteField("time");
-        schema.WriteField("number");
-        schema.WriteField("count");
-      }
-
-      aWriter.StartArrayProperty("data");
-      uint64_t previousNumber = 0;
-      int64_t previousCount = 0;
-      for (size_t i = 0; i < size; i++) {
-        // Encode as deltas, and only encode if different than the last sample
-        if (i == 0 || samples[i].mNumber != previousNumber ||
-            samples[i].mCount != previousCount) {
-          MOZ_ASSERT(i == 0 || samples[i].mTime >= samples[i - 1].mTime);
-          MOZ_ASSERT(samples[i].mNumber >= previousNumber);
-          MOZ_ASSERT(samples[i].mNumber - previousNumber <=
-                     uint64_t(std::numeric_limits<int64_t>::max()));
-
-          AutoArraySchemaWriter writer(aWriter);
-          writer.DoubleElement(TIME, samples[i].mTime);
-          writer.IntElement(NUMBER, static_cast<int64_t>(samples[i].mNumber -
-                                                         previousNumber));
-          writer.IntElement(COUNT, samples[i].mCount - previousCount);
-          previousNumber = samples[i].mNumber;
-          previousCount = samples[i].mCount;
-        }
-      }
-      aWriter.EndArray();   // data
-      aWriter.EndObject();  // samples
-    }
-    aWriter.EndObject();  // sample groups
-    aWriter.End();        // for each counter
-  }
-  aWriter.EndArray();  // counters
-}
-
-void ProfileBuffer::StreamMemoryToJSON(SpliceableJSONWriter& aWriter,
-                                       const TimeStamp& aProcessStartTime,
-                                       double aSinceTime) const {
-  enum Schema : uint32_t { TIME = 0, RSS = 1, USS = 2 };
-
-  EntryGetter e(*this);
-
-  aWriter.StartObjectProperty("memory");
-  // Stream all memory (rss/uss) data. We skip other entries, because we
-  // process them in StreamSamplesToJSON()/etc.
-  aWriter.IntProperty("initial_heap", 0);  // XXX FIX
-  aWriter.StartObjectProperty("samples");
-  {
-    JSONSchemaWriter schema(aWriter);
-    schema.WriteField("time");
-    schema.WriteField("rss");
-    schema.WriteField("uss");
-  }
-
-  aWriter.StartArrayProperty("data");
-  int64_t previous_rss = 0;
-  int64_t previous_uss = 0;
-  while (e.Has()) {
-    // valid sequence: Resident, Unshared?, Time
-    if (e.Get().IsResidentMemory()) {
-      int64_t rss = e.Get().GetInt64();
-      int64_t uss = 0;
-      e.Next();
-      if (e.Has()) {
-        if (e.Get().IsUnsharedMemory()) {
-          uss = e.Get().GetDouble();
-          e.Next();
-          if (!e.Has()) {
-            break;
-          }
-        }
-        if (e.Get().IsTime()) {
-          double time = e.Get().GetDouble();
-          if (time >= aSinceTime &&
-              (previous_rss != rss || previous_uss != uss)) {
-            AutoArraySchemaWriter writer(aWriter);
-            writer.DoubleElement(TIME, time);
-            writer.IntElement(RSS, rss);
-            if (uss != 0) {
-              writer.IntElement(USS, uss);
-            }
-            previous_rss = rss;
-            previous_uss = uss;
-          }
-        } else {
+        if (!e.Has() || !e.Get().IsTime()) {
           ERROR_AND_CONTINUE("expected a Time entry");
         }
+        double time = e.Get().GetDouble();
+        if (time >= aSinceTime) {
+          e.Next();
+          while (e.Has() && e.Get().IsCounterKey()) {
+            uint64_t key = e.Get().GetUint64();
+            CounterKeyedSamples& data = LookupOrAdd(counter, key);
+            e.Next();
+            if (!e.Has() || !e.Get().IsCount()) {
+              ERROR_AND_CONTINUE("expected a Count entry");
+            }
+            int64_t count = e.Get().GetUint64();
+            e.Next();
+            uint64_t number;
+            if (!e.Has() || !e.Get().IsNumber()) {
+              number = 0;
+            } else {
+              number = e.Get().GetInt64();
+            }
+            CounterKeyedSample sample = {time, number, count};
+            MOZ_RELEASE_ASSERT(data.append(sample));
+          }
+        } else {
+          // skip counter sample - only need to skip the initial counter
+          // id, then let the loop at the top skip the rest
+        }
       }
+      e.Next();
     }
-    e.Next();
-  }
-  aWriter.EndArray();   // data
-  aWriter.EndObject();  // samples
-  aWriter.EndObject();  // memory
+    // we have a map of a map of counter entries; dump them to JSON
+    if (counters.count() == 0) {
+      return;
+    }
+
+    aWriter.StartArrayProperty("counters");
+    for (auto iter = counters.iter(); !iter.done(); iter.next()) {
+      CounterMap& counter = iter.get().value();
+      const BaseProfilerCount* base_counter =
+          static_cast<const BaseProfilerCount*>(iter.get().key());
+
+      aWriter.Start();
+      aWriter.StringProperty("name", base_counter->mLabel);
+      aWriter.StringProperty("category", base_counter->mCategory);
+      aWriter.StringProperty("description", base_counter->mDescription);
+
+      aWriter.StartObjectProperty("sample_groups");
+      for (auto counter_iter = counter.iter(); !counter_iter.done();
+           counter_iter.next()) {
+        CounterKeyedSamples& samples = counter_iter.get().value();
+        uint64_t key = counter_iter.get().key();
+
+        size_t size = samples.length();
+        if (size == 0) {
+          continue;
+        }
+        aWriter.IntProperty("id", static_cast<int64_t>(key));
+        aWriter.StartObjectProperty("samples");
+        {
+          // XXX Can we assume a missing count means 0?
+          JSONSchemaWriter schema(aWriter);
+          schema.WriteField("time");
+          schema.WriteField("number");
+          schema.WriteField("count");
+        }
+
+        aWriter.StartArrayProperty("data");
+        uint64_t previousNumber = 0;
+        int64_t previousCount = 0;
+        for (size_t i = 0; i < size; i++) {
+          // Encode as deltas, and only encode if different than the last sample
+          if (i == 0 || samples[i].mNumber != previousNumber ||
+              samples[i].mCount != previousCount) {
+            MOZ_ASSERT(i == 0 || samples[i].mTime >= samples[i - 1].mTime);
+            MOZ_ASSERT(samples[i].mNumber >= previousNumber);
+            MOZ_ASSERT(samples[i].mNumber - previousNumber <=
+                       uint64_t(std::numeric_limits<int64_t>::max()));
+
+            AutoArraySchemaWriter writer(aWriter);
+            writer.DoubleElement(TIME, samples[i].mTime);
+            writer.IntElement(NUMBER, static_cast<int64_t>(samples[i].mNumber -
+                                                           previousNumber));
+            writer.IntElement(COUNT, samples[i].mCount - previousCount);
+            previousNumber = samples[i].mNumber;
+            previousCount = samples[i].mCount;
+          }
+        }
+        aWriter.EndArray();   // data
+        aWriter.EndObject();  // samples
+      }
+      aWriter.EndObject();  // sample groups
+      aWriter.End();        // for each counter
+    }
+    aWriter.EndArray();  // counters
+  });
 }
+
 #  undef ERROR_AND_CONTINUE
 
 static void AddPausedRange(SpliceableJSONWriter& aWriter, const char* aReason,
@@ -1198,180 +1150,234 @@ static void AddPausedRange(SpliceableJSONWriter& aWriter, const char* aReason,
 
 void ProfileBuffer::StreamPausedRangesToJSON(SpliceableJSONWriter& aWriter,
                                              double aSinceTime) const {
-  EntryGetter e(*this);
+  mEntries.Read([&](BlocksRingBuffer::Reader* aReader) {
+    MOZ_ASSERT(
+        aReader,
+        "BlocksRingBuffer cannot be out-of-session when sampler is running");
 
-  Maybe<double> currentPauseStartTime;
-  Maybe<double> currentCollectionStartTime;
+    EntryGetter e(*aReader);
 
-  while (e.Has()) {
-    if (e.Get().IsPause()) {
-      currentPauseStartTime = Some(e.Get().GetDouble());
-    } else if (e.Get().IsResume()) {
-      AddPausedRange(aWriter, "profiler-paused", currentPauseStartTime,
-                     Some(e.Get().GetDouble()));
-      currentPauseStartTime = Nothing();
-    } else if (e.Get().IsCollectionStart()) {
-      currentCollectionStartTime = Some(e.Get().GetDouble());
-    } else if (e.Get().IsCollectionEnd()) {
-      AddPausedRange(aWriter, "collecting", currentCollectionStartTime,
-                     Some(e.Get().GetDouble()));
-      currentCollectionStartTime = Nothing();
+    Maybe<double> currentPauseStartTime;
+    Maybe<double> currentCollectionStartTime;
+
+    while (e.Has()) {
+      if (e.Get().IsPause()) {
+        currentPauseStartTime = Some(e.Get().GetDouble());
+      } else if (e.Get().IsResume()) {
+        AddPausedRange(aWriter, "profiler-paused", currentPauseStartTime,
+                       Some(e.Get().GetDouble()));
+        currentPauseStartTime = Nothing();
+      } else if (e.Get().IsCollectionStart()) {
+        currentCollectionStartTime = Some(e.Get().GetDouble());
+      } else if (e.Get().IsCollectionEnd()) {
+        AddPausedRange(aWriter, "collecting", currentCollectionStartTime,
+                       Some(e.Get().GetDouble()));
+        currentCollectionStartTime = Nothing();
+      }
+      e.Next();
     }
-    e.Next();
-  }
 
-  if (currentPauseStartTime) {
-    AddPausedRange(aWriter, "profiler-paused", currentPauseStartTime,
-                   Nothing());
-  }
-  if (currentCollectionStartTime) {
-    AddPausedRange(aWriter, "collecting", currentCollectionStartTime,
-                   Nothing());
-  }
+    if (currentPauseStartTime) {
+      AddPausedRange(aWriter, "profiler-paused", currentPauseStartTime,
+                     Nothing());
+    }
+    if (currentCollectionStartTime) {
+      AddPausedRange(aWriter, "collecting", currentCollectionStartTime,
+                     Nothing());
+    }
+  });
 }
 
 bool ProfileBuffer::DuplicateLastSample(int aThreadId,
                                         const TimeStamp& aProcessStartTime,
                                         Maybe<uint64_t>& aLastSample) {
-  if (aLastSample && *aLastSample < mRangeStart) {
-    // The last sample is no longer within the buffer range, so we cannot use
-    // it. Reset the stored buffer position to Nothing().
-    aLastSample.reset();
-  }
-
   if (!aLastSample) {
     return false;
   }
 
-  uint64_t lastSampleStartPos = *aLastSample;
+  BlocksRingBuffer tempBuffer(BlocksRingBuffer::ThreadSafety::WithoutMutex,
+                              mDuplicationBuffer.get(), DuplicationBufferBytes);
 
-  MOZ_RELEASE_ASSERT(GetEntry(lastSampleStartPos).IsThreadId() &&
-                     GetEntry(lastSampleStartPos).GetInt() == aThreadId);
+  const bool ok = mEntries.Read([&](BlocksRingBuffer::Reader* aReader) {
+    MOZ_ASSERT(
+        aReader,
+        "BlocksRingBuffer cannot be out-of-session when sampler is running");
+
+    EntryGetter e(*aReader, *aLastSample);
+
+    if (e.CurPos() != *aLastSample) {
+      // The last sample is no longer within the buffer range, so we cannot
+      // use it. Reset the stored buffer position to Nothing().
+      aLastSample.reset();
+      return false;
+    }
+
+    MOZ_RELEASE_ASSERT(e.Has() && e.Get().IsThreadId() &&
+                       e.Get().GetInt() == aThreadId);
+
+    e.Next();
+
+    // Go through the whole entry and duplicate it, until we find the next
+    // one.
+    while (e.Has()) {
+      switch (e.Get().GetKind()) {
+        case ProfileBufferEntry::Kind::Pause:
+        case ProfileBufferEntry::Kind::Resume:
+        case ProfileBufferEntry::Kind::CollectionStart:
+        case ProfileBufferEntry::Kind::CollectionEnd:
+        case ProfileBufferEntry::Kind::ThreadId:
+          // We're done.
+          return true;
+        case ProfileBufferEntry::Kind::Time:
+          // Copy with new time
+          AddEntry(tempBuffer,
+                   ProfileBufferEntry::Time(
+                       (TimeStamp::NowUnfuzzed() - aProcessStartTime)
+                           .ToMilliseconds()));
+          break;
+        case ProfileBufferEntry::Kind::CounterKey:
+        case ProfileBufferEntry::Kind::Number:
+        case ProfileBufferEntry::Kind::Count:
+        case ProfileBufferEntry::Kind::Responsiveness:
+          // Don't copy anything not part of a thread's stack sample
+          break;
+        case ProfileBufferEntry::Kind::CounterId:
+          // CounterId is normally followed by Time - if so, we'd like
+          // to skip it.  If we duplicate Time, it won't hurt anything, just
+          // waste buffer space (and this can happen if the CounterId has
+          // fallen off the end of the buffer, but Time (and Number/Count)
+          // are still in the buffer).
+          e.Next();
+          if (e.Has() && e.Get().GetKind() != ProfileBufferEntry::Kind::Time) {
+            // this would only happen if there was an invalid sequence
+            // in the buffer.  Don't skip it.
+            continue;
+          }
+          // we've skipped Time
+          break;
+        case ProfileBufferEntry::Kind::ProfilerOverheadTime:
+          // ProfilerOverheadTime is normally followed by
+          // ProfilerOverheadDuration*4 - if so, we'd like to skip it. Don't
+          // duplicate, as we are in the middle of a sampling and will soon
+          // capture its own overhead.
+          e.Next();
+          // A missing Time would only happen if there was an invalid
+          // sequence in the buffer. Don't skip unexpected entry.
+          if (e.Has() &&
+              e.Get().GetKind() !=
+                  ProfileBufferEntry::Kind::ProfilerOverheadDuration) {
+            continue;
+          }
+          e.Next();
+          if (e.Has() &&
+              e.Get().GetKind() !=
+                  ProfileBufferEntry::Kind::ProfilerOverheadDuration) {
+            continue;
+          }
+          e.Next();
+          if (e.Has() &&
+              e.Get().GetKind() !=
+                  ProfileBufferEntry::Kind::ProfilerOverheadDuration) {
+            continue;
+          }
+          e.Next();
+          if (e.Has() &&
+              e.Get().GetKind() !=
+                  ProfileBufferEntry::Kind::ProfilerOverheadDuration) {
+            continue;
+          }
+          // we've skipped ProfilerOverheadTime and
+          // ProfilerOverheadDuration*4.
+          break;
+        default: {
+          // Copy anything else we don't know about.
+          AddEntry(tempBuffer, e.Get());
+          break;
+        }
+      }
+      e.Next();
+    }
+    return true;
+  });
+
+  if (!ok) {
+    return false;
+  }
+
+  // If the buffer was big enough, there won't be any cleared blocks.
+  if (tempBuffer.GetState().mClearedBlockCount != 0) {
+    // No need to try to read stack again as it won't fit. Reset the stored
+    // buffer position to Nothing().
+    aLastSample.reset();
+    return false;
+  }
 
   aLastSample = Some(AddThreadIdEntry(aThreadId));
 
-  EntryGetter e(*this, lastSampleStartPos + 1);
+  tempBuffer.Read([&](BlocksRingBuffer::Reader* aReader) {
+    MOZ_ASSERT(aReader, "tempBuffer cannot be out-of-session");
 
-  // Go through the whole entry and duplicate it, until we find the next one.
-  while (e.Has()) {
-    switch (e.Get().GetKind()) {
-      case ProfileBufferEntry::Kind::Pause:
-      case ProfileBufferEntry::Kind::Resume:
-      case ProfileBufferEntry::Kind::CollectionStart:
-      case ProfileBufferEntry::Kind::CollectionEnd:
-      case ProfileBufferEntry::Kind::ThreadId:
-        // We're done.
-        return true;
-      case ProfileBufferEntry::Kind::Time:
-        // Copy with new time
-        AddEntry(ProfileBufferEntry::Time(
-            (TimeStamp::Now() - aProcessStartTime).ToMilliseconds()));
-        break;
-      case ProfileBufferEntry::Kind::Marker:
-      case ProfileBufferEntry::Kind::ResidentMemory:
-      case ProfileBufferEntry::Kind::UnsharedMemory:
-      case ProfileBufferEntry::Kind::CounterKey:
-      case ProfileBufferEntry::Kind::Number:
-      case ProfileBufferEntry::Kind::Count:
-      case ProfileBufferEntry::Kind::Responsiveness:
-        // Don't copy anything not part of a thread's stack sample
-        break;
-      case ProfileBufferEntry::Kind::CounterId:
-        // CounterId is normally followed by Time - if so, we'd like
-        // to skip it.  If we duplicate Time, it won't hurt anything, just
-        // waste buffer space (and this can happen if the CounterId has
-        // fallen off the end of the buffer, but Time (and Number/Count)
-        // are still in the buffer).
-        e.Next();
-        if (e.Has() && e.Get().GetKind() != ProfileBufferEntry::Kind::Time) {
-          // this would only happen if there was an invalid sequence
-          // in the buffer.  Don't skip it.
-          continue;
-        }
-        // we've skipped Time
-        break;
-      case ProfileBufferEntry::Kind::ProfilerOverheadTime:
-        // ProfilerOverheadTime is normally followed by
-        // ProfilerOverheadDuration*4 - if so, we'd like to skip it. Don't
-        // duplicate, as we are in the middle of a sampling and will soon
-        // capture its own overhead.
-        e.Next();
-        // A missing Time would only happen if there was an invalid sequence
-        // in the buffer. Don't skip unexpected entry.
-        if (e.Has() && e.Get().GetKind() !=
-                           ProfileBufferEntry::Kind::ProfilerOverheadDuration) {
-          continue;
-        }
-        e.Next();
-        if (e.Has() && e.Get().GetKind() !=
-                           ProfileBufferEntry::Kind::ProfilerOverheadDuration) {
-          continue;
-        }
-        e.Next();
-        if (e.Has() && e.Get().GetKind() !=
-                           ProfileBufferEntry::Kind::ProfilerOverheadDuration) {
-          continue;
-        }
-        e.Next();
-        if (e.Has() && e.Get().GetKind() !=
-                           ProfileBufferEntry::Kind::ProfilerOverheadDuration) {
-          continue;
-        }
-        // we've skipped ProfilerOverheadTime and ProfilerOverheadDuration*4.
-        break;
-      default: {
-        // Copy anything else we don't know about.
-        ProfileBufferEntry entry = e.Get();
-        AddEntry(entry);
-        break;
-      }
+    EntryGetter e(*aReader);
+
+    while (e.Has()) {
+      AddEntry(e.Get());
+      e.Next();
     }
-    e.Next();
-  }
+  });
+
   return true;
 }
 
 void ProfileBuffer::DiscardSamplesBeforeTime(double aTime) {
-  EntryGetter e(*this);
-  for (;;) {
-    // This block skips entries until we find the start of the next sample.
-    // This is useful in three situations.
-    //
-    // - The circular buffer overwrites old entries, so when we start parsing
-    //   we might be in the middle of a sample, and we must skip forward to the
-    //   start of the next sample.
-    //
-    // - We skip samples that don't have an appropriate ThreadId or Time.
-    //
-    // - We skip range Pause, Resume, CollectionStart, Marker, and CollectionEnd
-    //   entries between samples.
-    while (e.Has()) {
-      if (e.Get().IsThreadId()) {
-        break;
-      } else {
-        e.Next();
-      }
-    }
+  const BlockIndex firstBlockToKeep =
+      mEntries.Read([&](BlocksRingBuffer::Reader* aReader) {
+        MOZ_ASSERT(aReader,
+                   "BlocksRingBuffer cannot be out-of-session when sampler is "
+                   "running");
 
-    if (!e.Has()) {
-      break;
-    }
+        EntryGetter e(*aReader);
 
-    MOZ_RELEASE_ASSERT(e.Get().IsThreadId());
-    uint64_t sampleStartPos = e.CurPos();
-    e.Next();
+        const BlockIndex bufferStartPos = e.CurBlockIndex();
+        for (;;) {
+          // This block skips entries until we find the start of the next
+          // sample. This is useful in three situations.
+          //
+          // - The circular buffer overwrites old entries, so when we start
+          //   parsing we might be in the middle of a sample, and we must skip
+          //   forward to the start of the next sample.
+          //
+          // - We skip samples that don't have an appropriate ThreadId or Time.
+          //
+          // - We skip range Pause, Resume, CollectionStart, Marker, and
+          //   CollectionEnd entries between samples.
+          while (e.Has()) {
+            if (e.Get().IsThreadId()) {
+              break;
+            }
+            e.Next();
+          }
 
-    if (e.Has() && e.Get().IsTime()) {
-      double sampleTime = e.Get().GetDouble();
+          if (!e.Has()) {
+            return bufferStartPos;
+          }
 
-      if (sampleTime >= aTime) {
-        // This is the first sample within the window of time that we want to
-        // keep. Throw away all samples before sampleStartPos and return.
-        mRangeStart = sampleStartPos;
-        return;
-      }
-    }
-  }
+          MOZ_RELEASE_ASSERT(e.Get().IsThreadId());
+          const BlockIndex sampleStartPos = e.CurBlockIndex();
+          e.Next();
+
+          if (e.Has() && e.Get().IsTime()) {
+            double sampleTime = e.Get().GetDouble();
+
+            if (sampleTime >= aTime) {
+              // This is the first sample within the window of time that we want
+              // to keep. Throw away all samples before sampleStartPos and
+              // return.
+              return sampleStartPos;
+            }
+          }
+        }
+      });
+  mEntries.ClearBefore(firstBlockToKeep);
 }
 
 // END ProfileBuffer
diff --git a/mozglue/baseprofiler/core/ProfileBufferEntry.h b/mozglue/baseprofiler/core/ProfileBufferEntry.h
index be9d7a827e..5128acc193 100644
--- a/mozglue/baseprofiler/core/ProfileBufferEntry.h
+++ b/mozglue/baseprofiler/core/ProfileBufferEntry.h
@@ -21,44 +21,62 @@
 namespace mozilla {
 namespace baseprofiler {
 
-class ProfilerMarker;
-
 // NOTE!  If you add entries, you need to verify if they need to be added to the
 // switch statement in DuplicateLastSample!
-#define FOR_EACH_PROFILE_BUFFER_ENTRY_KIND(MACRO)                   \
-  MACRO(CategoryPair, int)                                          \
-  MACRO(CollectionStart, double)                                    \
-  MACRO(CollectionEnd, double)                                      \
-  MACRO(Label, const char*)                                         \
-  MACRO(FrameFlags, uint64_t)                                       \
-  MACRO(DynamicStringFragment, char*) /* char[kNumChars], really */ \
-  MACRO(JitReturnAddr, void*)                                       \
-  MACRO(LineNumber, int)                                            \
-  MACRO(ColumnNumber, int)                                          \
-  MACRO(NativeLeafAddr, void*)                                      \
-  MACRO(Marker, ProfilerMarker*)                                    \
-  MACRO(Pause, double)                                              \
-  MACRO(Responsiveness, double)                                     \
-  MACRO(Resume, double)                                             \
-  MACRO(ThreadId, int)                                              \
-  MACRO(Time, double)                                               \
-  MACRO(ResidentMemory, uint64_t)                                   \
-  MACRO(UnsharedMemory, uint64_t)                                   \
-  MACRO(CounterId, void*)                                           \
-  MACRO(CounterKey, uint64_t)                                       \
-  MACRO(Number, uint64_t)                                           \
-  MACRO(Count, int64_t)                                             \
-  MACRO(ProfilerOverheadTime, double)                               \
-  MACRO(ProfilerOverheadDuration, double)
+// This will evaluate the MACRO with (KIND, TYPE, SIZE)
+#define FOR_EACH_PROFILE_BUFFER_ENTRY_KIND(MACRO)                    \
+  MACRO(CategoryPair, int, sizeof(int))                              \
+  MACRO(CollectionStart, double, sizeof(double))                     \
+  MACRO(CollectionEnd, double, sizeof(double))                       \
+  MACRO(Label, const char*, sizeof(const char*))                     \
+  MACRO(FrameFlags, uint64_t, sizeof(uint64_t))                      \
+  MACRO(DynamicStringFragment, char*, ProfileBufferEntry::kNumChars) \
+  MACRO(JitReturnAddr, void*, sizeof(void*))                         \
+  MACRO(LineNumber, int, sizeof(int))                                \
+  MACRO(ColumnNumber, int, sizeof(int))                              \
+  MACRO(NativeLeafAddr, void*, sizeof(void*))                        \
+  MACRO(Pause, double, sizeof(double))                               \
+  MACRO(Responsiveness, double, sizeof(double))                      \
+  MACRO(Resume, double, sizeof(double))                              \
+  MACRO(ThreadId, int, sizeof(int))                                  \
+  MACRO(Time, double, sizeof(double))                                \
+  MACRO(CounterId, void*, sizeof(void*))                             \
+  MACRO(CounterKey, uint64_t, sizeof(uint64_t))                      \
+  MACRO(Number, uint64_t, sizeof(uint64_t))                          \
+  MACRO(Count, int64_t, sizeof(int64_t))                             \
+  MACRO(ProfilerOverheadTime, double, sizeof(double))                \
+  MACRO(ProfilerOverheadDuration, double, sizeof(double))
 
 class ProfileBufferEntry {
  public:
-  enum class Kind : uint8_t {
+  // The `Kind` is a single byte identifying the type of data that is actually
+  // stored in a `ProfileBufferEntry`, as per the list in
+  // `FOR_EACH_PROFILE_BUFFER_ENTRY_KIND`.
+  //
+  // This byte is also used to identify entries in BlocksRingBuffer blocks, for
+  // both "legacy" entries that do contain a `ProfileBufferEntry`, and for new
+  // types of entries that may carry more data of different types.
+  // TODO: Eventually each type of "legacy" entry should be replaced with newer,
+  // more efficient kinds of entries (e.g., stack frames could be stored in one
+  // bigger entry, instead of multiple `ProfileBufferEntry`s); then we could
+  // discard `ProfileBufferEntry` and move this enum to a more appropriate spot.
+  using KindUnderlyingType = uint8_t;
+  enum class Kind : KindUnderlyingType {
     INVALID = 0,
-#define KIND(k, t) k,
+#define KIND(KIND, TYPE, SIZE) KIND,
     FOR_EACH_PROFILE_BUFFER_ENTRY_KIND(KIND)
 #undef KIND
-        LIMIT
+
+    // Any value under `LEGACY_LIMIT` represents a `ProfileBufferEntry`.
+    LEGACY_LIMIT,
+
+    // Any value starting here does *not* represent a `ProfileBufferEntry` and
+    // requires separate decoding and handling.
+
+    // Marker data, including payload.
+    MarkerData = LEGACY_LIMIT,
+
+    MODERN_LIMIT
   };
 
   ProfileBufferEntry();
@@ -72,24 +90,23 @@ class ProfileBufferEntry {
   ProfileBufferEntry(Kind aKind, const char* aString);
   ProfileBufferEntry(Kind aKind, char aChars[kNumChars]);
   ProfileBufferEntry(Kind aKind, void* aPtr);
-  ProfileBufferEntry(Kind aKind, ProfilerMarker* aMarker);
   ProfileBufferEntry(Kind aKind, double aDouble);
   ProfileBufferEntry(Kind aKind, int64_t aInt64);
   ProfileBufferEntry(Kind aKind, uint64_t aUint64);
   ProfileBufferEntry(Kind aKind, int aInt);
 
  public:
-#define CTOR(k, t)                            \
-  static ProfileBufferEntry k(t aVal) {       \
-    return ProfileBufferEntry(Kind::k, aVal); \
+#define CTOR(KIND, TYPE, SIZE)                   \
+  static ProfileBufferEntry KIND(TYPE aVal) {    \
+    return ProfileBufferEntry(Kind::KIND, aVal); \
   }
   FOR_EACH_PROFILE_BUFFER_ENTRY_KIND(CTOR)
 #undef CTOR
 
   Kind GetKind() const { return mKind; }
 
-#define IS_KIND(k, t) \
-  bool Is##k() const { return mKind == Kind::k; }
+#define IS_KIND(KIND, TYPE, SIZE) \
+  bool Is##KIND() const { return mKind == Kind::KIND; }
   FOR_EACH_PROFILE_BUFFER_ENTRY_KIND(IS_KIND)
 #undef IS_KIND
 
@@ -106,7 +123,6 @@ class ProfileBufferEntry {
 
   const char* GetString() const;
   void* GetPtr() const;
-  ProfilerMarker* GetMarker() const;
   double GetDouble() const;
   int GetInt() const;
   int64_t GetInt64() const;
@@ -342,11 +358,14 @@ class UniqueStacks {
 //     "schema":
 //     {
 //       "location": 0,       /* index into stringTable */
-//       "implementation": 1, /* index into stringTable */
-//       "optimizations": 2,  /* arbitrary JSON */
-//       "line": 3,           /* number */
-//       "column": 4,         /* number */
-//       "category": 5        /* number */
+//       "relevantForJS": 1,  /* bool */
+//       "implementation": 2, /* index into stringTable */
+//       "optimizations": 3,  /* arbitrary JSON */
+//       "line": 4,           /* number */
+//       "column": 5,         /* number */
+//       "category": 6        /* index into profile.meta.categories */
+//       "subcategory": 7     /* index into
+//       profile.meta.categories[category].subcategories */
 //     },
 //     "data":
 //     [
@@ -403,24 +422,6 @@ class UniqueStacks {
 //     },
 //     /* more counters */
 //   ],
-//   "memory":
-//   {
-//     "initial_heap": 12345678,
-//     "samples:
-//     {
-//       "schema":
-//       {
-//         "time": 1,            /* number */
-//         "rss": 2,             /* number */
-//         "uss": 3              /* number */
-//       },
-//       "data":
-//       [
-//         /* { time: 0.1, rss: 12345678, uss: 87654321} */
-//         [ 0.1, 12345678, 87654321 ]
-//       ]
-//     },
-//   },
 // }
 //
 
diff --git a/mozglue/baseprofiler/core/ProfiledThreadData.cpp b/mozglue/baseprofiler/core/ProfiledThreadData.cpp
index 34d0e011c1..f103df6f01 100644
--- a/mozglue/baseprofiler/core/ProfiledThreadData.cpp
+++ b/mozglue/baseprofiler/core/ProfiledThreadData.cpp
@@ -62,6 +62,7 @@ void ProfiledThreadData::StreamJSON(const ProfileBuffer& aBuffer,
         schema.WriteField("line");
         schema.WriteField("column");
         schema.WriteField("category");
+        schema.WriteField("subcategory");
       }
 
       aWriter.StartArrayProperty("data");
@@ -123,8 +124,6 @@ void StreamSamplesAndMarkers(const char* aName, int aThreadId,
       schema.WriteField("stack");
       schema.WriteField("time");
       schema.WriteField("responsiveness");
-      schema.WriteField("rss");
-      schema.WriteField("uss");
     }
 
     aWriter.StartArrayProperty("data");
diff --git a/mozglue/baseprofiler/core/ProfiledThreadData.h b/mozglue/baseprofiler/core/ProfiledThreadData.h
index de1810b949..a7711ce146 100644
--- a/mozglue/baseprofiler/core/ProfiledThreadData.h
+++ b/mozglue/baseprofiler/core/ProfiledThreadData.h
@@ -54,7 +54,7 @@ class ProfiledThreadData final {
     MOZ_ASSERT(!mBufferPositionWhenReceivedJSContext,
                "JSContext should have been cleared before the thread was "
                "unregistered");
-    mUnregisterTime = TimeStamp::Now();
+    mUnregisterTime = TimeStamp::NowUnfuzzed();
     mBufferPositionWhenUnregistered = Some(aBufferPosition);
   }
   Maybe<uint64_t> BufferPositionWhenUnregistered() {
diff --git a/mozglue/baseprofiler/core/ProfilerBacktrace.cpp b/mozglue/baseprofiler/core/ProfilerBacktrace.cpp
index 0734362a07..60cb6c2601 100644
--- a/mozglue/baseprofiler/core/ProfilerBacktrace.cpp
+++ b/mozglue/baseprofiler/core/ProfilerBacktrace.cpp
@@ -16,9 +16,23 @@
 namespace mozilla {
 namespace baseprofiler {
 
-ProfilerBacktrace::ProfilerBacktrace(const char* aName, int aThreadId,
-                                     UniquePtr<ProfileBuffer> aBuffer)
-    : mName(strdup(aName)), mThreadId(aThreadId), mBuffer(std::move(aBuffer)) {}
+ProfilerBacktrace::ProfilerBacktrace(
+    const char* aName, int aThreadId,
+    UniquePtr<BlocksRingBuffer> aBlocksRingBuffer,
+    UniquePtr<ProfileBuffer> aProfileBuffer)
+    : mName(strdup(aName)),
+      mThreadId(aThreadId),
+      mBlocksRingBuffer(std::move(aBlocksRingBuffer)),
+      mProfileBuffer(std::move(aProfileBuffer)) {
+  MOZ_ASSERT(
+      !!mBlocksRingBuffer,
+      "ProfilerBacktrace only takes a non-null UniquePtr<BlocksRingBuffer>");
+  MOZ_ASSERT(
+      !!mProfileBuffer,
+      "ProfilerBacktrace only takes a non-null UniquePtr<ProfileBuffer>");
+  MOZ_ASSERT(!mBlocksRingBuffer->IsThreadSafe(),
+             "ProfilerBacktrace only takes a non-thread-safe BlocksRingBuffer");
+}
 
 ProfilerBacktrace::~ProfilerBacktrace() {}
 
@@ -26,10 +40,10 @@ void ProfilerBacktrace::StreamJSON(SpliceableJSONWriter& aWriter,
                                    const TimeStamp& aProcessStartTime,
                                    UniqueStacks& aUniqueStacks) {
   // Unlike ProfiledThreadData::StreamJSON, we don't need to call
-  // ProfileBuffer::AddJITInfoForRange because mBuffer does not contain any
-  // JitReturnAddr entries. For synchronous samples, JIT frames get expanded
+  // ProfileBuffer::AddJITInfoForRange because mProfileBuffer does not contain
+  // any JitReturnAddr entries. For synchronous samples, JIT frames get expanded
   // at sample time.
-  StreamSamplesAndMarkers(mName.get(), mThreadId, *mBuffer.get(), aWriter, "",
+  StreamSamplesAndMarkers(mName.get(), mThreadId, *mProfileBuffer, aWriter, "",
                           aProcessStartTime,
                           /* aRegisterTime */ TimeStamp(),
                           /* aUnregisterTime */ TimeStamp(),
@@ -37,6 +51,28 @@ void ProfilerBacktrace::StreamJSON(SpliceableJSONWriter& aWriter,
 }
 
 }  // namespace baseprofiler
+
+// static
+template <typename Destructor>
+UniquePtr<baseprofiler::ProfilerBacktrace, Destructor> BlocksRingBuffer::
+    Deserializer<UniquePtr<baseprofiler::ProfilerBacktrace, Destructor>>::Read(
+        BlocksRingBuffer::EntryReader& aER) {
+  auto blocksRingBuffer = aER.ReadObject<UniquePtr<BlocksRingBuffer>>();
+  if (!blocksRingBuffer) {
+    return nullptr;
+  }
+  MOZ_ASSERT(!blocksRingBuffer->IsThreadSafe(),
+             "ProfilerBacktrace only stores non-thread-safe BlocksRingBuffers");
+  int threadId = aER.ReadObject<int>();
+  std::string name = aER.ReadObject<std::string>();
+  auto profileBuffer =
+      MakeUnique<baseprofiler::ProfileBuffer>(*blocksRingBuffer);
+  return UniquePtr<baseprofiler::ProfilerBacktrace, Destructor>{
+      new baseprofiler::ProfilerBacktrace(name.c_str(), threadId,
+                                          std::move(blocksRingBuffer),
+                                          std::move(profileBuffer))};
+};
+
 }  // namespace mozilla
 
 #endif  // MOZ_BASE_PROFILER
diff --git a/mozglue/baseprofiler/core/ProfilerBacktrace.h b/mozglue/baseprofiler/core/ProfilerBacktrace.h
index 195934d1ce..31e8f8bea9 100644
--- a/mozglue/baseprofiler/core/ProfilerBacktrace.h
+++ b/mozglue/baseprofiler/core/ProfilerBacktrace.h
@@ -9,6 +9,7 @@
 
 namespace mozilla {
 
+class BlocksRingBuffer;
 class TimeStamp;
 
 namespace baseprofiler {
@@ -22,7 +23,8 @@ class UniqueStacks;
 class ProfilerBacktrace {
  public:
   ProfilerBacktrace(const char* aName, int aThreadId,
-                    UniquePtr<ProfileBuffer> aBuffer);
+                    UniquePtr<BlocksRingBuffer> aBlocksRingBuffer,
+                    UniquePtr<ProfileBuffer> aProfileBuffer);
   ~ProfilerBacktrace();
 
   // ProfilerBacktraces' stacks are deduplicated in the context of the
@@ -36,15 +38,90 @@ class ProfilerBacktrace {
                   UniqueStacks& aUniqueStacks);
 
  private:
-  ProfilerBacktrace(const ProfilerBacktrace&);
-  ProfilerBacktrace& operator=(const ProfilerBacktrace&);
+  // Used to de/serialize a ProfilerBacktrace.
+  friend struct BlocksRingBuffer::Serializer<ProfilerBacktrace>;
+  friend struct BlocksRingBuffer::Deserializer<ProfilerBacktrace>;
 
   UniqueFreePtr<char> mName;
   int mThreadId;
-  UniquePtr<ProfileBuffer> mBuffer;
+  // `BlocksRingBuffer` in which `mProfileBuffer` stores its data; must be
+  // located before `mProfileBuffer` so that it's destroyed after.
+  UniquePtr<BlocksRingBuffer> mBlocksRingBuffer;
+  UniquePtr<ProfileBuffer> mProfileBuffer;
 };
 
 }  // namespace baseprofiler
+
+// Format: [ UniquePtr<BlockRingsBuffer> | threadId | name ]
+// Initial len==0 marks a nullptr or empty backtrace.
+template <>
+struct BlocksRingBuffer::Serializer<baseprofiler::ProfilerBacktrace> {
+  static Length Bytes(const baseprofiler::ProfilerBacktrace& aBacktrace) {
+    if (!aBacktrace.mProfileBuffer) {
+      // No backtrace buffer.
+      return ULEB128Size<Length>(0);
+    }
+    auto bufferBytes = SumBytes(*aBacktrace.mBlocksRingBuffer);
+    if (bufferBytes == 0) {
+      // Empty backtrace buffer.
+      return ULEB128Size<Length>(0);
+    }
+    return bufferBytes +
+           SumBytes(aBacktrace.mThreadId,
+                    WrapBlocksRingBufferUnownedCString(aBacktrace.mName.get()));
+  }
+
+  static void Write(EntryWriter& aEW,
+                    const baseprofiler::ProfilerBacktrace& aBacktrace) {
+    if (!aBacktrace.mProfileBuffer ||
+        SumBytes(aBacktrace.mBlocksRingBuffer) == 0) {
+      // No backtrace buffer, or it is empty.
+      aEW.WriteULEB128<Length>(0);
+      return;
+    }
+    aEW.WriteObject(aBacktrace.mBlocksRingBuffer);
+    aEW.WriteObject(aBacktrace.mThreadId);
+    aEW.WriteObject(WrapBlocksRingBufferUnownedCString(aBacktrace.mName.get()));
+  }
+};
+
+template <typename Destructor>
+struct BlocksRingBuffer::Serializer<
+    UniquePtr<baseprofiler::ProfilerBacktrace, Destructor>> {
+  static Length Bytes(const UniquePtr<baseprofiler::ProfilerBacktrace,
+                                      Destructor>& aBacktrace) {
+    if (!aBacktrace) {
+      // Null backtrace pointer (treated like an empty backtrace).
+      return ULEB128Size<Length>(0);
+    }
+    return SumBytes(*aBacktrace);
+  }
+
+  static void Write(EntryWriter& aEW,
+                    const UniquePtr<baseprofiler::ProfilerBacktrace,
+                                    Destructor>& aBacktrace) {
+    if (!aBacktrace) {
+      // Null backtrace pointer (treated like an empty backtrace).
+      aEW.WriteULEB128<Length>(0);
+      return;
+    }
+    aEW.WriteObject(*aBacktrace);
+  }
+};
+
+template <typename Destructor>
+struct BlocksRingBuffer::Deserializer<
+    UniquePtr<baseprofiler::ProfilerBacktrace, Destructor>> {
+  static void ReadInto(
+      EntryReader& aER,
+      UniquePtr<baseprofiler::ProfilerBacktrace, Destructor>& aBacktrace) {
+    aBacktrace = Read(aER);
+  }
+
+  static UniquePtr<baseprofiler::ProfilerBacktrace, Destructor> Read(
+      EntryReader& aER);
+};
+
 }  // namespace mozilla
 
 #endif  // __PROFILER_BACKTRACE_H
diff --git a/mozglue/baseprofiler/core/ProfilerMarker.h b/mozglue/baseprofiler/core/ProfilerMarker.h
deleted file mode 100644
index 7c9b19dda2..0000000000
--- a/mozglue/baseprofiler/core/ProfilerMarker.h
+++ /dev/null
@@ -1,173 +0,0 @@
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-#ifndef ProfilerMarker_h
-#define ProfilerMarker_h
-
-#include "ProfileBufferEntry.h"
-#include "BaseProfileJSONWriter.h"
-#include "BaseProfilerMarkerPayload.h"
-
-#include "mozilla/UniquePtrExtensions.h"
-
-namespace mozilla {
-namespace baseprofiler {
-
-template <typename T>
-class ProfilerLinkedList;
-
-class ProfilerMarker {
-  friend class ProfilerLinkedList<ProfilerMarker>;
-
- public:
-  explicit ProfilerMarker(const char* aMarkerName,
-                          ProfilingCategoryPair aCategoryPair, int aThreadId,
-                          UniquePtr<ProfilerMarkerPayload> aPayload = nullptr,
-                          double aTime = 0)
-      : mMarkerName(strdup(aMarkerName)),
-        mPayload(std::move(aPayload)),
-        mNext{nullptr},
-        mTime(aTime),
-        mPositionInBuffer{0},
-        mThreadId{aThreadId},
-        mCategoryPair{aCategoryPair} {}
-
-  void SetPositionInBuffer(uint64_t aPosition) {
-    mPositionInBuffer = aPosition;
-  }
-
-  bool HasExpired(uint64_t aBufferRangeStart) const {
-    return mPositionInBuffer < aBufferRangeStart;
-  }
-
-  double GetTime() const { return mTime; }
-
-  int GetThreadId() const { return mThreadId; }
-
-  void StreamJSON(SpliceableJSONWriter& aWriter,
-                  const TimeStamp& aProcessStartTime,
-                  UniqueStacks& aUniqueStacks) const {
-    // Schema:
-    //   [name, time, category, data]
-
-    aWriter.StartArrayElement();
-    {
-      aUniqueStacks.mUniqueStrings->WriteElement(aWriter, mMarkerName.get());
-      aWriter.DoubleElement(mTime);
-      const ProfilingCategoryPairInfo& info =
-          GetProfilingCategoryPairInfo(mCategoryPair);
-      aWriter.IntElement(unsigned(info.mCategory));
-      // TODO: Store the callsite for this marker if available:
-      // if have location data
-      //   b.NameValue(marker, "location", ...);
-      if (mPayload) {
-        aWriter.StartObjectElement(SpliceableJSONWriter::SingleLineStyle);
-        { mPayload->StreamPayload(aWriter, aProcessStartTime, aUniqueStacks); }
-        aWriter.EndObject();
-      }
-    }
-    aWriter.EndArray();
-  }
-
- private:
-  UniqueFreePtr<char> mMarkerName;
-  UniquePtr<ProfilerMarkerPayload> mPayload;
-  ProfilerMarker* mNext;
-  double mTime;
-  uint64_t mPositionInBuffer;
-  int mThreadId;
-  ProfilingCategoryPair mCategoryPair;
-};
-
-template <typename T>
-class ProfilerLinkedList {
- public:
-  ProfilerLinkedList() : mHead(nullptr), mTail(nullptr) {}
-
-  void insert(T* aElem) {
-    if (!mTail) {
-      mHead = aElem;
-      mTail = aElem;
-    } else {
-      mTail->mNext = aElem;
-      mTail = aElem;
-    }
-    aElem->mNext = nullptr;
-  }
-
-  T* popHead() {
-    if (!mHead) {
-      MOZ_ASSERT(false);
-      return nullptr;
-    }
-
-    T* head = mHead;
-
-    mHead = head->mNext;
-    if (!mHead) {
-      mTail = nullptr;
-    }
-
-    return head;
-  }
-
-  const T* peek() { return mHead; }
-
- private:
-  T* mHead;
-  T* mTail;
-};
-
-typedef ProfilerLinkedList<ProfilerMarker> ProfilerMarkerLinkedList;
-
-template <typename T>
-class ProfilerSignalSafeLinkedList {
- public:
-  ProfilerSignalSafeLinkedList() : mSignalLock(false) {}
-
-  ~ProfilerSignalSafeLinkedList() {
-    if (mSignalLock) {
-      // Some thread is modifying the list. We should only be released on that
-      // thread.
-      abort();
-    }
-
-    while (mList.peek()) {
-      delete mList.popHead();
-    }
-  }
-
-  // Insert an item into the list. Must only be called from the owning thread.
-  // Must not be called while the list from accessList() is being accessed.
-  // In the profiler, we ensure that by interrupting the profiled thread
-  // (which is the one that owns this list and calls insert() on it) until
-  // we're done reading the list from the signal handler.
-  void insert(T* aElement) {
-    MOZ_ASSERT(aElement);
-
-    mSignalLock = true;
-
-    mList.insert(aElement);
-
-    mSignalLock = false;
-  }
-
-  // Called within signal, from any thread, possibly while insert() is in the
-  // middle of modifying the list (on the owning thread). Will return null if
-  // that is the case.
-  // Function must be reentrant.
-  ProfilerLinkedList<T>* accessList() { return mSignalLock ? nullptr : &mList; }
-
- private:
-  ProfilerLinkedList<T> mList;
-
-  // If this is set, then it's not safe to read the list because its contents
-  // are being changed.
-  Atomic<bool> mSignalLock;
-};
-
-}  // namespace baseprofiler
-}  // namespace mozilla
-
-#endif  // ProfilerMarker_h
diff --git a/mozglue/baseprofiler/core/ProfilerMarkerPayload.cpp b/mozglue/baseprofiler/core/ProfilerMarkerPayload.cpp
index 64579c6fb2..f03dc53342 100644
--- a/mozglue/baseprofiler/core/ProfilerMarkerPayload.cpp
+++ b/mozglue/baseprofiler/core/ProfilerMarkerPayload.cpp
@@ -20,6 +20,77 @@
 namespace mozilla {
 namespace baseprofiler {
 
+static UniquePtr<ProfilerMarkerPayload> DeserializeNothing(
+    mozilla::BlocksRingBuffer::EntryReader&) {
+  return nullptr;
+}
+
+// Number of currently-registered deserializers.
+// Starting at 1 for the initial `DeserializeNothing`.
+// static
+Atomic<ProfilerMarkerPayload::DeserializerTagAtomic, ReleaseAcquire,
+       recordreplay::Behavior::DontPreserve>
+    ProfilerMarkerPayload::sDeserializerCount{1};
+
+// Initialize `sDeserializers` with `DeserializeNothing` at index 0, all others
+// are nullptrs.
+// static
+ProfilerMarkerPayload::Deserializer
+    ProfilerMarkerPayload::sDeserializers[DeserializerMax] = {
+        DeserializeNothing};
+
+// static
+ProfilerMarkerPayload::DeserializerTag
+ProfilerMarkerPayload::TagForDeserializer(
+    ProfilerMarkerPayload::Deserializer aDeserializer) {
+  if (!aDeserializer) {
+    return 0;
+  }
+  // Start first search at index 0.
+  DeserializerTagAtomic start = 0;
+  for (;;) {
+    // Read the current count of deserializers.
+    const DeserializerTagAtomic tagCount = sDeserializerCount;
+    if (tagCount == 0) {
+      // Someone else is currently writing into the array, loop around until we
+      // get a valid count.
+      continue;
+    }
+    for (DeserializerTagAtomic i = start; i < tagCount; ++i) {
+      if (sDeserializers[i] == aDeserializer) {
+        // Deserializer already registered, return its tag.
+        return static_cast<ProfilerMarkerPayload::DeserializerTag>(i);
+      }
+    }
+    // Not found yet, let's register this new deserializer.
+    // Make sure we haven't reached the limit yet.
+    MOZ_RELEASE_ASSERT(tagCount < DeserializerMax);
+    // Reserve `tagCount` as an index, if not already claimed:
+    // If `sDeserializerCount` is still at our previously-read `tagCount`,
+    // replace it with a special 0 value to indicate a write.
+    if (sDeserializerCount.compareExchange(tagCount, 0)) {
+      // Here we own the `tagCount` index, write the deserializer there.
+      sDeserializers[tagCount] = aDeserializer;
+      // And publish by writing the real new count (1 past our index).
+      sDeserializerCount = tagCount + 1;
+      return static_cast<ProfilerMarkerPayload::DeserializerTag>(tagCount);
+    }
+    // Someone else beat us to grab an index, and it could be for the same
+    // deserializer! So let's just try searching starting from our recorded
+    // `tagCount` (and maybe attempting again to register). It should be rare
+    // enough and quick enough that it won't impact performances.
+    start = tagCount;
+  }
+}
+
+// static
+ProfilerMarkerPayload::Deserializer ProfilerMarkerPayload::DeserializerForTag(
+    ProfilerMarkerPayload::DeserializerTag aTag) {
+  MOZ_RELEASE_ASSERT(aTag < DeserializerMax);
+  MOZ_RELEASE_ASSERT(aTag < sDeserializerCount);
+  return sDeserializers[aTag];
+}
+
 static void MOZ_ALWAYS_INLINE WriteTime(SpliceableJSONWriter& aWriter,
                                         const TimeStamp& aProcessStartTime,
                                         const TimeStamp& aTime,
@@ -30,33 +101,113 @@ static void MOZ_ALWAYS_INLINE WriteTime(SpliceableJSONWriter& aWriter,
 }
 
 void ProfilerMarkerPayload::StreamType(const char* aMarkerType,
-                                       SpliceableJSONWriter& aWriter) {
+                                       SpliceableJSONWriter& aWriter) const {
   MOZ_ASSERT(aMarkerType);
   aWriter.StringProperty("type", aMarkerType);
 }
 
+BlocksRingBuffer::Length
+ProfilerMarkerPayload::CommonPropsTagAndSerializationBytes() const {
+  return sizeof(DeserializerTag) +
+         BlocksRingBuffer::SumBytes(mCommonProps.mStartTime,
+                                    mCommonProps.mEndTime, mCommonProps.mStack,
+                                    mCommonProps.mDocShellId,
+                                    mCommonProps.mDocShellHistoryId);
+}
+
+void ProfilerMarkerPayload::SerializeTagAndCommonProps(
+    DeserializerTag aDeserializerTag,
+    BlocksRingBuffer::EntryWriter& aEntryWriter) const {
+  aEntryWriter.WriteObject(aDeserializerTag);
+  aEntryWriter.WriteObject(mCommonProps.mStartTime);
+  aEntryWriter.WriteObject(mCommonProps.mEndTime);
+  aEntryWriter.WriteObject(mCommonProps.mStack);
+  aEntryWriter.WriteObject(mCommonProps.mDocShellId);
+  aEntryWriter.WriteObject(mCommonProps.mDocShellHistoryId);
+}
+
+// static
+ProfilerMarkerPayload::CommonProps
+ProfilerMarkerPayload::DeserializeCommonProps(
+    BlocksRingBuffer::EntryReader& aEntryReader) {
+  CommonProps props;
+  aEntryReader.ReadIntoObject(props.mStartTime);
+  aEntryReader.ReadIntoObject(props.mEndTime);
+  aEntryReader.ReadIntoObject(props.mStack);
+  aEntryReader.ReadIntoObject(props.mDocShellId);
+  aEntryReader.ReadIntoObject(props.mDocShellHistoryId);
+  return props;
+}
+
 void ProfilerMarkerPayload::StreamCommonProps(
     const char* aMarkerType, SpliceableJSONWriter& aWriter,
-    const TimeStamp& aProcessStartTime, UniqueStacks& aUniqueStacks) {
+    const TimeStamp& aProcessStartTime, UniqueStacks& aUniqueStacks) const {
   StreamType(aMarkerType, aWriter);
-  WriteTime(aWriter, aProcessStartTime, mStartTime, "startTime");
-  WriteTime(aWriter, aProcessStartTime, mEndTime, "endTime");
-  if (mDocShellId) {
-    aWriter.StringProperty("docShellId", mDocShellId->c_str());
+  WriteTime(aWriter, aProcessStartTime, mCommonProps.mStartTime, "startTime");
+  WriteTime(aWriter, aProcessStartTime, mCommonProps.mEndTime, "endTime");
+  if (mCommonProps.mDocShellId) {
+    aWriter.StringProperty("docShellId", mCommonProps.mDocShellId->c_str());
   }
-  if (mDocShellHistoryId) {
-    aWriter.DoubleProperty("docshellHistoryId", mDocShellHistoryId.ref());
+  if (mCommonProps.mDocShellHistoryId) {
+    aWriter.DoubleProperty("docshellHistoryId",
+                           mCommonProps.mDocShellHistoryId.ref());
   }
-  if (mStack) {
+  if (mCommonProps.mStack) {
     aWriter.StartObjectProperty("stack");
-    { mStack->StreamJSON(aWriter, aProcessStartTime, aUniqueStacks); }
+    {
+      mCommonProps.mStack->StreamJSON(aWriter, aProcessStartTime,
+                                      aUniqueStacks);
+    }
     aWriter.EndObject();
   }
 }
 
+TracingMarkerPayload::TracingMarkerPayload(
+    const char* aCategory, TracingKind aKind,
+    const Maybe<std::string>& aDocShellId,
+    const Maybe<uint32_t>& aDocShellHistoryId, UniqueProfilerBacktrace aCause)
+    : ProfilerMarkerPayload(aDocShellId, aDocShellHistoryId, std::move(aCause)),
+      mCategory(aCategory),
+      mKind(aKind) {}
+
+TracingMarkerPayload::TracingMarkerPayload(CommonProps&& aCommonProps,
+                                           const char* aCategory,
+                                           TracingKind aKind)
+    : ProfilerMarkerPayload(std::move(aCommonProps)),
+      mCategory(aCategory),
+      mKind(aKind) {}
+
+TracingMarkerPayload::~TracingMarkerPayload() = default;
+
+BlocksRingBuffer::Length TracingMarkerPayload::TagAndSerializationBytes()
+    const {
+  return CommonPropsTagAndSerializationBytes() +
+         BlocksRingBuffer::SumBytes(WrapBlocksRingBufferRawPointer(mCategory),
+                                    mKind);
+}
+
+void TracingMarkerPayload::SerializeTagAndPayload(
+    BlocksRingBuffer::EntryWriter& aEntryWriter) const {
+  static const DeserializerTag tag = TagForDeserializer(Deserialize);
+  SerializeTagAndCommonProps(tag, aEntryWriter);
+  aEntryWriter.WriteObject(WrapBlocksRingBufferRawPointer(mCategory));
+  aEntryWriter.WriteObject(mKind);
+}
+
+// static
+UniquePtr<ProfilerMarkerPayload> TracingMarkerPayload::Deserialize(
+    BlocksRingBuffer::EntryReader& aEntryReader) {
+  ProfilerMarkerPayload::CommonProps props =
+      DeserializeCommonProps(aEntryReader);
+  const char* category = aEntryReader.ReadObject<const char*>();
+  TracingKind kind = aEntryReader.ReadObject<TracingKind>();
+  return UniquePtr<ProfilerMarkerPayload>(
+      new TracingMarkerPayload(std::move(props), category, kind));
+}
+
 void TracingMarkerPayload::StreamPayload(SpliceableJSONWriter& aWriter,
                                          const TimeStamp& aProcessStartTime,
-                                         UniqueStacks& aUniqueStacks) {
+                                         UniqueStacks& aUniqueStacks) const {
   StreamCommonProps("tracing", aWriter, aProcessStartTime, aUniqueStacks);
 
   if (mCategory) {
@@ -70,20 +221,135 @@ void TracingMarkerPayload::StreamPayload(SpliceableJSONWriter& aWriter,
   }
 }
 
+FileIOMarkerPayload::FileIOMarkerPayload(const char* aOperation,
+                                         const char* aSource,
+                                         const char* aFilename,
+                                         const TimeStamp& aStartTime,
+                                         const TimeStamp& aEndTime,
+                                         UniqueProfilerBacktrace aStack)
+    : ProfilerMarkerPayload(aStartTime, aEndTime, Nothing(), Nothing(),
+                            std::move(aStack)),
+      mSource(aSource),
+      mOperation(aOperation ? strdup(aOperation) : nullptr),
+      mFilename(aFilename ? strdup(aFilename) : nullptr) {
+  MOZ_ASSERT(aSource);
+}
+
+FileIOMarkerPayload::FileIOMarkerPayload(CommonProps&& aCommonProps,
+                                         const char* aSource,
+                                         UniqueFreePtr<char>&& aOperation,
+                                         UniqueFreePtr<char>&& aFilename)
+    : ProfilerMarkerPayload(std::move(aCommonProps)),
+      mSource(aSource),
+      mOperation(std::move(aOperation)),
+      mFilename(std::move(aFilename)) {}
+
+FileIOMarkerPayload::~FileIOMarkerPayload() = default;
+
+BlocksRingBuffer::Length FileIOMarkerPayload::TagAndSerializationBytes() const {
+  return CommonPropsTagAndSerializationBytes() +
+         BlocksRingBuffer::SumBytes(WrapBlocksRingBufferRawPointer(mSource),
+                                    mOperation, mFilename);
+}
+
+void FileIOMarkerPayload::SerializeTagAndPayload(
+    BlocksRingBuffer::EntryWriter& aEntryWriter) const {
+  static const DeserializerTag tag = TagForDeserializer(Deserialize);
+  SerializeTagAndCommonProps(tag, aEntryWriter);
+  aEntryWriter.WriteObject(WrapBlocksRingBufferRawPointer(mSource));
+  aEntryWriter.WriteObject(mOperation);
+  aEntryWriter.WriteObject(mFilename);
+}
+
+// static
+UniquePtr<ProfilerMarkerPayload> FileIOMarkerPayload::Deserialize(
+    BlocksRingBuffer::EntryReader& aEntryReader) {
+  ProfilerMarkerPayload::CommonProps props =
+      DeserializeCommonProps(aEntryReader);
+  auto source = aEntryReader.ReadObject<const char*>();
+  auto operation = aEntryReader.ReadObject<UniqueFreePtr<char>>();
+  auto filename = aEntryReader.ReadObject<UniqueFreePtr<char>>();
+  return UniquePtr<ProfilerMarkerPayload>(new FileIOMarkerPayload(
+      std::move(props), source, std::move(operation), std::move(filename)));
+}
+
 void FileIOMarkerPayload::StreamPayload(SpliceableJSONWriter& aWriter,
                                         const TimeStamp& aProcessStartTime,
-                                        UniqueStacks& aUniqueStacks) {
+                                        UniqueStacks& aUniqueStacks) const {
   StreamCommonProps("FileIO", aWriter, aProcessStartTime, aUniqueStacks);
   aWriter.StringProperty("operation", mOperation.get());
   aWriter.StringProperty("source", mSource);
-  if (mFilename) {
+  if (mFilename && *mFilename) {
     aWriter.StringProperty("filename", mFilename.get());
   }
 }
 
+UserTimingMarkerPayload::UserTimingMarkerPayload(
+    const std::string& aName, const TimeStamp& aStartTime,
+    const Maybe<std::string>& aDocShellId,
+    const Maybe<uint32_t>& aDocShellHistoryId)
+    : ProfilerMarkerPayload(aStartTime, aStartTime, aDocShellId,
+                            aDocShellHistoryId),
+      mEntryType("mark"),
+      mName(aName) {}
+
+UserTimingMarkerPayload::UserTimingMarkerPayload(
+    const std::string& aName, const Maybe<std::string>& aStartMark,
+    const Maybe<std::string>& aEndMark, const TimeStamp& aStartTime,
+    const TimeStamp& aEndTime, const Maybe<std::string>& aDocShellId,
+    const Maybe<uint32_t>& aDocShellHistoryId)
+    : ProfilerMarkerPayload(aStartTime, aEndTime, aDocShellId,
+                            aDocShellHistoryId),
+      mEntryType("measure"),
+      mName(aName),
+      mStartMark(aStartMark),
+      mEndMark(aEndMark) {}
+
+UserTimingMarkerPayload::UserTimingMarkerPayload(
+    CommonProps&& aCommonProps, const char* aEntryType, std::string&& aName,
+    Maybe<std::string>&& aStartMark, Maybe<std::string>&& aEndMark)
+    : ProfilerMarkerPayload(std::move(aCommonProps)),
+      mEntryType(aEntryType),
+      mName(std::move(aName)),
+      mStartMark(std::move(aStartMark)),
+      mEndMark(std::move(aEndMark)) {}
+
+UserTimingMarkerPayload::~UserTimingMarkerPayload() = default;
+
+BlocksRingBuffer::Length UserTimingMarkerPayload::TagAndSerializationBytes()
+    const {
+  return CommonPropsTagAndSerializationBytes() +
+         BlocksRingBuffer::SumBytes(WrapBlocksRingBufferRawPointer(mEntryType),
+                                    mName, mStartMark, mEndMark);
+}
+
+void UserTimingMarkerPayload::SerializeTagAndPayload(
+    BlocksRingBuffer::EntryWriter& aEntryWriter) const {
+  static const DeserializerTag tag = TagForDeserializer(Deserialize);
+  SerializeTagAndCommonProps(tag, aEntryWriter);
+  aEntryWriter.WriteObject(WrapBlocksRingBufferRawPointer(mEntryType));
+  aEntryWriter.WriteObject(mName);
+  aEntryWriter.WriteObject(mStartMark);
+  aEntryWriter.WriteObject(mEndMark);
+}
+
+// static
+UniquePtr<ProfilerMarkerPayload> UserTimingMarkerPayload::Deserialize(
+    BlocksRingBuffer::EntryReader& aEntryReader) {
+  ProfilerMarkerPayload::CommonProps props =
+      DeserializeCommonProps(aEntryReader);
+  auto entryType = aEntryReader.ReadObject<const char*>();
+  auto name = aEntryReader.ReadObject<std::string>();
+  auto startMark = aEntryReader.ReadObject<Maybe<std::string>>();
+  auto endMark = aEntryReader.ReadObject<Maybe<std::string>>();
+  return UniquePtr<ProfilerMarkerPayload>(
+      new UserTimingMarkerPayload(std::move(props), entryType, std::move(name),
+                                  std::move(startMark), std::move(endMark)));
+}
+
 void UserTimingMarkerPayload::StreamPayload(SpliceableJSONWriter& aWriter,
                                             const TimeStamp& aProcessStartTime,
-                                            UniqueStacks& aUniqueStacks) {
+                                            UniqueStacks& aUniqueStacks) const {
   StreamCommonProps("UserTiming", aWriter, aProcessStartTime, aUniqueStacks);
   aWriter.StringProperty("name", mName.c_str());
   aWriter.StringProperty("entryType", mEntryType);
@@ -100,31 +366,181 @@ void UserTimingMarkerPayload::StreamPayload(SpliceableJSONWriter& aWriter,
   }
 }
 
+TextMarkerPayload::TextMarkerPayload(const std::string& aText,
+                                     const TimeStamp& aStartTime)
+    : ProfilerMarkerPayload(aStartTime, aStartTime), mText(aText) {}
+
+TextMarkerPayload::TextMarkerPayload(const std::string& aText,
+                                     const TimeStamp& aStartTime,
+                                     const TimeStamp& aEndTime)
+    : ProfilerMarkerPayload(aStartTime, aEndTime), mText(aText) {}
+
+TextMarkerPayload::TextMarkerPayload(const std::string& aText,
+                                     const TimeStamp& aStartTime,
+                                     const Maybe<std::string>& aDocShellId,
+                                     const Maybe<uint32_t>& aDocShellHistoryId)
+    : ProfilerMarkerPayload(aStartTime, aStartTime, aDocShellId,
+                            aDocShellHistoryId),
+      mText(aText) {}
+
+TextMarkerPayload::TextMarkerPayload(const std::string& aText,
+                                     const TimeStamp& aStartTime,
+                                     const TimeStamp& aEndTime,
+                                     const Maybe<std::string>& aDocShellId,
+                                     const Maybe<uint32_t>& aDocShellHistoryId,
+                                     UniqueProfilerBacktrace aCause)
+    : ProfilerMarkerPayload(aStartTime, aEndTime, aDocShellId,
+                            aDocShellHistoryId, std::move(aCause)),
+      mText(aText) {}
+
+TextMarkerPayload::TextMarkerPayload(CommonProps&& aCommonProps,
+                                     std::string&& aText)
+    : ProfilerMarkerPayload(std::move(aCommonProps)), mText(std::move(aText)) {}
+
+TextMarkerPayload::~TextMarkerPayload() = default;
+
+BlocksRingBuffer::Length TextMarkerPayload::TagAndSerializationBytes() const {
+  return CommonPropsTagAndSerializationBytes() +
+         BlocksRingBuffer::SumBytes(mText);
+}
+
+void TextMarkerPayload::SerializeTagAndPayload(
+    BlocksRingBuffer::EntryWriter& aEntryWriter) const {
+  static const DeserializerTag tag = TagForDeserializer(Deserialize);
+  SerializeTagAndCommonProps(tag, aEntryWriter);
+  aEntryWriter.WriteObject(mText);
+}
+
+// static
+UniquePtr<ProfilerMarkerPayload> TextMarkerPayload::Deserialize(
+    BlocksRingBuffer::EntryReader& aEntryReader) {
+  ProfilerMarkerPayload::CommonProps props =
+      DeserializeCommonProps(aEntryReader);
+  auto text = aEntryReader.ReadObject<std::string>();
+  return UniquePtr<ProfilerMarkerPayload>(
+      new TextMarkerPayload(std::move(props), std::move(text)));
+}
+
 void TextMarkerPayload::StreamPayload(SpliceableJSONWriter& aWriter,
                                       const TimeStamp& aProcessStartTime,
-                                      UniqueStacks& aUniqueStacks) {
+                                      UniqueStacks& aUniqueStacks) const {
   StreamCommonProps("Text", aWriter, aProcessStartTime, aUniqueStacks);
   aWriter.StringProperty("name", mText.c_str());
 }
 
+LogMarkerPayload::LogMarkerPayload(const char* aModule, const char* aText,
+                                   const TimeStamp& aStartTime)
+    : ProfilerMarkerPayload(aStartTime, aStartTime),
+      mModule(aModule),
+      mText(aText) {}
+
+LogMarkerPayload::LogMarkerPayload(CommonProps&& aCommonProps,
+                                   std::string&& aModule, std::string&& aText)
+    : ProfilerMarkerPayload(std::move(aCommonProps)),
+      mModule(std::move(aModule)),
+      mText(std::move(aText)) {}
+
+LogMarkerPayload::~LogMarkerPayload() = default;
+
+BlocksRingBuffer::Length LogMarkerPayload::TagAndSerializationBytes() const {
+  return CommonPropsTagAndSerializationBytes() +
+         BlocksRingBuffer::SumBytes(mModule, mText);
+}
+
+void LogMarkerPayload::SerializeTagAndPayload(
+    BlocksRingBuffer::EntryWriter& aEntryWriter) const {
+  static const DeserializerTag tag = TagForDeserializer(Deserialize);
+  SerializeTagAndCommonProps(tag, aEntryWriter);
+  aEntryWriter.WriteObject(mModule);
+  aEntryWriter.WriteObject(mText);
+}
+
+// static
+UniquePtr<ProfilerMarkerPayload> LogMarkerPayload::Deserialize(
+    BlocksRingBuffer::EntryReader& aEntryReader) {
+  ProfilerMarkerPayload::CommonProps props =
+      DeserializeCommonProps(aEntryReader);
+  auto module = aEntryReader.ReadObject<std::string>();
+  auto text = aEntryReader.ReadObject<std::string>();
+  return UniquePtr<ProfilerMarkerPayload>(new LogMarkerPayload(
+      std::move(props), std::move(module), std::move(text)));
+}
+
 void LogMarkerPayload::StreamPayload(SpliceableJSONWriter& aWriter,
                                      const TimeStamp& aProcessStartTime,
-                                     UniqueStacks& aUniqueStacks) {
+                                     UniqueStacks& aUniqueStacks) const {
   StreamCommonProps("Log", aWriter, aProcessStartTime, aUniqueStacks);
   aWriter.StringProperty("name", mText.c_str());
   aWriter.StringProperty("module", mModule.c_str());
 }
 
+HangMarkerPayload::HangMarkerPayload(const TimeStamp& aStartTime,
+                                     const TimeStamp& aEndTime)
+    : ProfilerMarkerPayload(aStartTime, aEndTime) {}
+
+HangMarkerPayload::HangMarkerPayload(CommonProps&& aCommonProps)
+    : ProfilerMarkerPayload(std::move(aCommonProps)) {}
+
+HangMarkerPayload::~HangMarkerPayload() = default;
+
+BlocksRingBuffer::Length HangMarkerPayload::TagAndSerializationBytes() const {
+  return CommonPropsTagAndSerializationBytes();
+}
+
+void HangMarkerPayload::SerializeTagAndPayload(
+    BlocksRingBuffer::EntryWriter& aEntryWriter) const {
+  static const DeserializerTag tag = TagForDeserializer(Deserialize);
+  SerializeTagAndCommonProps(tag, aEntryWriter);
+}
+
+// static
+UniquePtr<ProfilerMarkerPayload> HangMarkerPayload::Deserialize(
+    BlocksRingBuffer::EntryReader& aEntryReader) {
+  ProfilerMarkerPayload::CommonProps props =
+      DeserializeCommonProps(aEntryReader);
+  return UniquePtr<ProfilerMarkerPayload>(
+      new HangMarkerPayload(std::move(props)));
+}
+
 void HangMarkerPayload::StreamPayload(SpliceableJSONWriter& aWriter,
                                       const TimeStamp& aProcessStartTime,
-                                      UniqueStacks& aUniqueStacks) {
+                                      UniqueStacks& aUniqueStacks) const {
   StreamCommonProps("BHR-detected hang", aWriter, aProcessStartTime,
                     aUniqueStacks);
 }
 
+LongTaskMarkerPayload::LongTaskMarkerPayload(const TimeStamp& aStartTime,
+                                             const TimeStamp& aEndTime)
+    : ProfilerMarkerPayload(aStartTime, aEndTime) {}
+
+LongTaskMarkerPayload::LongTaskMarkerPayload(CommonProps&& aCommonProps)
+    : ProfilerMarkerPayload(std::move(aCommonProps)) {}
+
+LongTaskMarkerPayload::~LongTaskMarkerPayload() = default;
+
+BlocksRingBuffer::Length LongTaskMarkerPayload::TagAndSerializationBytes()
+    const {
+  return CommonPropsTagAndSerializationBytes();
+}
+
+void LongTaskMarkerPayload::SerializeTagAndPayload(
+    BlocksRingBuffer::EntryWriter& aEntryWriter) const {
+  static const DeserializerTag tag = TagForDeserializer(Deserialize);
+  SerializeTagAndCommonProps(tag, aEntryWriter);
+}
+
+// static
+UniquePtr<ProfilerMarkerPayload> LongTaskMarkerPayload::Deserialize(
+    BlocksRingBuffer::EntryReader& aEntryReader) {
+  ProfilerMarkerPayload::CommonProps props =
+      DeserializeCommonProps(aEntryReader);
+  return UniquePtr<ProfilerMarkerPayload>(
+      new LongTaskMarkerPayload(std::move(props)));
+}
+
 void LongTaskMarkerPayload::StreamPayload(SpliceableJSONWriter& aWriter,
                                           const TimeStamp& aProcessStartTime,
-                                          UniqueStacks& aUniqueStacks) {
+                                          UniqueStacks& aUniqueStacks) const {
   StreamCommonProps("MainThreadLongTask", aWriter, aProcessStartTime,
                     aUniqueStacks);
   aWriter.StringProperty("category", "LongTask");
diff --git a/mozglue/baseprofiler/core/RegisteredThread.h b/mozglue/baseprofiler/core/RegisteredThread.h
index 34c9435570..4179f1912c 100644
--- a/mozglue/baseprofiler/core/RegisteredThread.h
+++ b/mozglue/baseprofiler/core/RegisteredThread.h
@@ -6,8 +6,6 @@
 #define RegisteredThread_h
 
 #include "platform.h"
-#include "ProfilerMarker.h"
-#include "BaseProfilerMarkerPayload.h"
 #include "ThreadInfo.h"
 
 #include "mozilla/UniquePtr.h"
@@ -33,25 +31,6 @@ class RacyRegisteredThread final {
 
   bool IsBeingProfiled() const { return mIsBeingProfiled; }
 
-  void AddPendingMarker(const char* aMarkerName,
-                        ProfilingCategoryPair aCategoryPair,
-                        UniquePtr<ProfilerMarkerPayload> aPayload,
-                        double aTime) {
-    // Note: We don't assert on mIsBeingProfiled, because it could have changed
-    // between the check in the caller and now.
-    ProfilerMarker* marker = new ProfilerMarker(
-        aMarkerName, aCategoryPair, mThreadId, std::move(aPayload), aTime);
-    mPendingMarkers.insert(marker);
-  }
-
-  // Called within signal. Function must be reentrant.
-  ProfilerMarkerLinkedList* GetPendingMarkers() {
-    // The profiled thread is interrupted, so we can access the list safely.
-    // Unless the profiled thread was in the middle of changing the list when
-    // we interrupted it - in that case, accessList() will return null.
-    return mPendingMarkers.accessList();
-  }
-
   // This is called on every profiler restart. Put things that should happen at
   // that time here.
   void ReinitializeOnResume() {
@@ -101,9 +80,6 @@ class RacyRegisteredThread final {
  private:
   class ProfilingStack mProfilingStack;
 
-  // A list of pending markers that must be moved to the circular buffer.
-  ProfilerSignalSafeLinkedList<ProfilerMarker> mPendingMarkers;
-
   // mThreadId contains the thread ID of the current thread. It is safe to read
   // this from multiple threads concurrently, as it will never be mutated.
   const int mThreadId;
diff --git a/mozglue/baseprofiler/core/ThreadInfo.h b/mozglue/baseprofiler/core/ThreadInfo.h
index 8bea675286..0a7f18fe69 100644
--- a/mozglue/baseprofiler/core/ThreadInfo.h
+++ b/mozglue/baseprofiler/core/ThreadInfo.h
@@ -18,7 +18,7 @@ namespace baseprofiler {
 class ThreadInfo final {
  public:
   ThreadInfo(const char* aName, int aThreadId, bool aIsMainThread,
-             const TimeStamp& aRegisterTime = TimeStamp::Now())
+             const TimeStamp& aRegisterTime = TimeStamp::NowUnfuzzed())
       : mName(aName),
         mRegisterTime(aRegisterTime),
         mThreadId(aThreadId),
diff --git a/mozglue/baseprofiler/core/platform-linux-android.cpp b/mozglue/baseprofiler/core/platform-linux-android.cpp
index 2bf3236d1f..576926a26a 100644
--- a/mozglue/baseprofiler/core/platform-linux-android.cpp
+++ b/mozglue/baseprofiler/core/platform-linux-android.cpp
@@ -286,7 +286,7 @@ void Sampler::Disable(PSLockRef aLock) {
 template <typename Func>
 void Sampler::SuspendAndSampleAndResumeThread(
     PSLockRef aLock, const RegisteredThread& aRegisteredThread,
-    const Func& aProcessRegs) {
+    const TimeStamp& aNow, const Func& aProcessRegs) {
   // Only one sampler thread can be sampling at once.  So we expect to have
   // complete control over |sSigHandlerCoordinator|.
   MOZ_ASSERT(!sSigHandlerCoordinator);
@@ -341,7 +341,7 @@ void Sampler::SuspendAndSampleAndResumeThread(
   // Extract the current register values.
   Registers regs;
   PopulateRegsFromContext(regs, &sSigHandlerCoordinator->mUContext);
-  aProcessRegs(regs);
+  aProcessRegs(regs, aNow);
 
   //----------------------------------------------------------------//
   // Resume the target thread.
@@ -385,7 +385,7 @@ static void* ThreadEntry(void* aArg) {
 
 SamplerThread::SamplerThread(PSLockRef aLock, uint32_t aActivityGeneration,
                              double aIntervalMilliseconds)
-    : Sampler(aLock),
+    : mSampler(aLock),
       mActivityGeneration(aActivityGeneration),
       mIntervalMicroseconds(
           std::max(1, int(floor(aIntervalMilliseconds * 1000 + 0.5)))) {
@@ -449,7 +449,7 @@ void SamplerThread::Stop(PSLockRef aLock) {
   // though this SamplerThread is still alive, because the next time the main
   // loop of Run() iterates it won't get past the mActivityGeneration check,
   // and so won't send any signals.
-  Sampler::Disable(aLock);
+  mSampler.Disable(aLock);
 }
 
 // END SamplerThread target specifics
diff --git a/mozglue/baseprofiler/core/platform-macos.cpp b/mozglue/baseprofiler/core/platform-macos.cpp
index 0653d76273..5f506a59d6 100644
--- a/mozglue/baseprofiler/core/platform-macos.cpp
+++ b/mozglue/baseprofiler/core/platform-macos.cpp
@@ -79,7 +79,7 @@ void Sampler::Disable(PSLockRef aLock) {}
 template <typename Func>
 void Sampler::SuspendAndSampleAndResumeThread(
     PSLockRef aLock, const RegisteredThread& aRegisteredThread,
-    const Func& aProcessRegs) {
+    const TimeStamp& aNow, const Func& aProcessRegs) {
   thread_act_t samplee_thread =
       aRegisteredThread.GetPlatformData()->ProfiledThread();
 
@@ -122,7 +122,7 @@ void Sampler::SuspendAndSampleAndResumeThread(
     regs.mFP = reinterpret_cast<Address>(state.REGISTER_FIELD(bp));
     regs.mLR = 0;
 
-    aProcessRegs(regs);
+    aProcessRegs(regs, aNow);
   }
 
 #undef REGISTER_FIELD
@@ -151,7 +151,7 @@ static void* ThreadEntry(void* aArg) {
 
 SamplerThread::SamplerThread(PSLockRef aLock, uint32_t aActivityGeneration,
                              double aIntervalMilliseconds)
-    : Sampler(aLock),
+    : mSampler(aLock),
       mActivityGeneration(aActivityGeneration),
       mIntervalMicroseconds(
           std::max(1, int(floor(aIntervalMilliseconds * 1000 + 0.5)))),
@@ -172,7 +172,7 @@ void SamplerThread::SleepMicro(uint32_t aMicroseconds) {
   // case where the usleep call is interrupted by a signal.
 }
 
-void SamplerThread::Stop(PSLockRef aLock) { Sampler::Disable(aLock); }
+void SamplerThread::Stop(PSLockRef aLock) { mSampler.Disable(aLock); }
 
 // END SamplerThread target specifics
 ////////////////////////////////////////////////////////////////////////
diff --git a/mozglue/baseprofiler/core/platform-win32.cpp b/mozglue/baseprofiler/core/platform-win32.cpp
index 830844f401..e8c6877a04 100644
--- a/mozglue/baseprofiler/core/platform-win32.cpp
+++ b/mozglue/baseprofiler/core/platform-win32.cpp
@@ -140,7 +140,7 @@ void Sampler::Disable(PSLockRef aLock) {}
 template <typename Func>
 void Sampler::SuspendAndSampleAndResumeThread(
     PSLockRef aLock, const RegisteredThread& aRegisteredThread,
-    const Func& aProcessRegs) {
+    const TimeStamp& aNow, const Func& aProcessRegs) {
   HANDLE profiled_thread =
       aRegisteredThread.GetPlatformData()->ProfiledThread();
   if (profiled_thread == nullptr) {
@@ -186,7 +186,7 @@ void Sampler::SuspendAndSampleAndResumeThread(
 
   Registers regs;
   PopulateRegsFromContext(regs, &context);
-  aProcessRegs(regs);
+  aProcessRegs(regs, aNow);
 
   //----------------------------------------------------------------//
   // Resume the target thread.
@@ -212,7 +212,7 @@ static unsigned int __stdcall ThreadEntry(void* aArg) {
 
 SamplerThread::SamplerThread(PSLockRef aLock, uint32_t aActivityGeneration,
                              double aIntervalMilliseconds)
-    : Sampler(aLock),
+    : mSampler(aLock),
       mActivityGeneration(aActivityGeneration),
       mIntervalMicroseconds(
           std::max(1, int(floor(aIntervalMilliseconds * 1000 + 0.5)))) {
@@ -251,7 +251,7 @@ void SamplerThread::SleepMicro(uint32_t aMicroseconds) {
   if (mIntervalMicroseconds >= 1000) {
     ::Sleep(std::max(1u, aMicroseconds / 1000));
   } else {
-    TimeStamp start = TimeStamp::Now();
+    TimeStamp start = TimeStamp::NowUnfuzzed();
     TimeStamp end = start + TimeDuration::FromMicroseconds(aMicroseconds);
 
     // First, sleep for as many whole milliseconds as possible.
@@ -260,7 +260,7 @@ void SamplerThread::SleepMicro(uint32_t aMicroseconds) {
     }
 
     // Then, spin until enough time has passed.
-    while (TimeStamp::Now() < end) {
+    while (TimeStamp::NowUnfuzzed() < end) {
       YieldProcessor();
     }
   }
@@ -279,7 +279,7 @@ void SamplerThread::Stop(PSLockRef aLock) {
     ::timeEndPeriod(mIntervalMicroseconds / 1000);
   }
 
-  Sampler::Disable(aLock);
+  mSampler.Disable(aLock);
 }
 
 // END SamplerThread target specifics
diff --git a/mozglue/baseprofiler/core/platform.cpp b/mozglue/baseprofiler/core/platform.cpp
index 9fabf2386e..0e95c11962 100644
--- a/mozglue/baseprofiler/core/platform.cpp
+++ b/mozglue/baseprofiler/core/platform.cpp
@@ -43,6 +43,8 @@
 // #include "memory_hooks.h"
 #  include "mozilla/ArrayUtils.h"
 #  include "mozilla/Atomics.h"
+#  include "mozilla/AutoProfilerLabel.h"
+#  include "mozilla/BaseProfilerDetail.h"
 #  include "mozilla/Printf.h"
 #  include "mozilla/Services.h"
 #  include "mozilla/StackWalk.h"
@@ -169,14 +171,11 @@ static uint32_t AvailableFeatures() {
   // Now remove features not supported on this platform/configuration.
   ProfilerFeature::ClearJava(features);
   ProfilerFeature::ClearJS(features);
-  ProfilerFeature::ClearMemory(features);
-  ProfilerFeature::ClearResponsiveness(features);
   ProfilerFeature::ClearScreenshots(features);
 #  if !defined(HAVE_NATIVE_UNWIND)
   ProfilerFeature::ClearStackWalk(features);
 #  endif
   ProfilerFeature::ClearTaskTracer(features);
-  ProfilerFeature::ClearTrackOptimizations(features);
   ProfilerFeature::ClearJSTracer(features);
 
   return features;
@@ -185,8 +184,7 @@ static uint32_t AvailableFeatures() {
 // Default features common to all contexts (even if not available).
 static uint32_t DefaultFeatures() {
   return ProfilerFeature::Java | ProfilerFeature::JS | ProfilerFeature::Leaf |
-         ProfilerFeature::StackWalk | ProfilerFeature::Threads |
-         ProfilerFeature::Responsiveness;
+         ProfilerFeature::StackWalk | ProfilerFeature::Threads;
 }
 
 // Extra default features when MOZ_BASE_PROFILER_STARTUP is set (even if not
@@ -194,7 +192,7 @@ static uint32_t DefaultFeatures() {
 static uint32_t StartupExtraDefaultFeatures() {
   // Enable mainthreadio by default for startup profiles as startup is heavy on
   // I/O operations, and main thread I/O is really important to see there.
-  return ProfilerFeature::MainThreadIO | ProfilerFeature::Memory;
+  return ProfilerFeature::MainThreadIO;
 }
 
 // The auto-lock/unlock mutex that guards accesses to CorePS and ActivePS.
@@ -212,10 +210,10 @@ class MOZ_RAII PSAutoLock {
   void operator=(const PSAutoLock&) = delete;
 
  private:
-  static PSMutex gPSMutex;
+  static detail::BaseProfilerMutex gPSMutex;
 };
 
-PSMutex PSAutoLock::gPSMutex;
+detail::BaseProfilerMutex PSAutoLock::gPSMutex;
 
 // Only functions that take a PSLockRef arg can access CorePS's and ActivePS's
 // fields.
@@ -258,7 +256,12 @@ class CorePS {
  private:
   CorePS()
       : mMainThreadId(profiler_current_thread_id()),
-        mProcessStartTime(TimeStamp::ProcessCreation())
+        mProcessStartTime(TimeStamp::ProcessCreation()),
+        // This needs its own mutex, because it is used concurrently from
+        // functions guarded by gPSMutex as well as others without safety (e.g.,
+        // profiler_add_marker). It is *not* used inside the critical section of
+        // the sampler, because mutexes cannot be used there.
+        mCoreBlocksRingBuffer(BlocksRingBuffer::ThreadSafety::WithMutex)
 #  ifdef USE_LUL_STACKWALK
         ,
         mLul(nullptr)
@@ -316,6 +319,9 @@ class CorePS {
   // No PSLockRef is needed for this field because it's immutable.
   PS_GET_LOCKLESS(TimeStamp, ProcessStartTime)
 
+  // No PSLockRef is needed for this field because it's thread-safe.
+  PS_GET_LOCKLESS(BlocksRingBuffer&, CoreBlocksRingBuffer)
+
   PS_GET(const Vector<UniquePtr<RegisteredThread>>&, RegisteredThreads)
 
   static void AppendRegisteredThread(
@@ -403,6 +409,17 @@ class CorePS {
   // The time that the process started.
   const TimeStamp mProcessStartTime;
 
+  // The thread-safe blocks-oriented ring buffer into which all profiling data
+  // is recorded.
+  // ActivePS controls the lifetime of the underlying contents buffer: When
+  // ActivePS does not exist, mCoreBlocksRingBuffer is empty and rejects all
+  // reads&writes; see ActivePS for further details.
+  // Note: This needs to live here outside of ActivePS, because some producers
+  // are indirectly controlled (e.g., by atomic flags) and therefore may still
+  // attempt to write some data shortly after ActivePS has shutdown and deleted
+  // the underlying buffer in memory.
+  BlocksRingBuffer mCoreBlocksRingBuffer;
+
   // Info on all the registered threads.
   // ThreadIds in mRegisteredThreads are unique.
   Vector<UniquePtr<RegisteredThread>> mRegisteredThreads;
@@ -457,7 +474,7 @@ class ActivePS {
     return aFeatures;
   }
 
-  ActivePS(PSLockRef aLock, uint32_t aCapacity, double aInterval,
+  ActivePS(PSLockRef aLock, PowerOfTwo32 aCapacity, double aInterval,
            uint32_t aFeatures, const char** aFilters, uint32_t aFilterCount,
            const Maybe<double>& aDuration)
       : mGeneration(sNextGeneration++),
@@ -465,11 +482,12 @@ class ActivePS {
         mDuration(aDuration),
         mInterval(aInterval),
         mFeatures(AdjustFeatures(aFeatures, aFilterCount)),
-        mBuffer(MakeUnique<ProfileBuffer>(aCapacity))
+        // 8 bytes per entry.
+        mProfileBuffer(CorePS::CoreBlocksRingBuffer(),
+                       PowerOfTwo32(aCapacity.Value() * 8)),
         // The new sampler thread doesn't start sampling immediately because the
         // main loop within Run() is blocked until this function's caller
         // unlocks gPSMutex.
-        ,
         mSamplerThread(NewSamplerThread(aLock, mGeneration, aInterval))
 #  undef HAS_FEATURE
         ,
@@ -520,7 +538,7 @@ class ActivePS {
   }
 
  public:
-  static void Create(PSLockRef aLock, uint32_t aCapacity, double aInterval,
+  static void Create(PSLockRef aLock, PowerOfTwo32 aCapacity, double aInterval,
                      uint32_t aFeatures, const char** aFilters,
                      uint32_t aFilterCount, const Maybe<double>& aDuration) {
     sInstance = new ActivePS(aLock, aCapacity, aInterval, aFeatures, aFilters,
@@ -537,7 +555,7 @@ class ActivePS {
 
   static bool Exists(PSLockRef) { return !!sInstance; }
 
-  static bool Equals(PSLockRef, uint32_t aCapacity,
+  static bool Equals(PSLockRef, PowerOfTwo32 aCapacity,
                      const Maybe<double>& aDuration, double aInterval,
                      uint32_t aFeatures, const char** aFilters,
                      uint32_t aFilterCount) {
@@ -560,7 +578,7 @@ class ActivePS {
   static size_t SizeOf(PSLockRef, MallocSizeOf aMallocSizeOf) {
     size_t n = aMallocSizeOf(sInstance);
 
-    n += sInstance->mBuffer->SizeOfIncludingThis(aMallocSizeOf);
+    n += sInstance->mProfileBuffer.SizeOfExcludingThis(aMallocSizeOf);
 
     // Measurement of the following members may be added later if DMD finds it
     // is worthwhile:
@@ -580,7 +598,7 @@ class ActivePS {
 
   PS_GET(uint32_t, Generation)
 
-  PS_GET(uint32_t, Capacity)
+  PS_GET(PowerOfTwo32, Capacity)
 
   PS_GET(Maybe<double>, Duration)
 
@@ -599,7 +617,7 @@ class ActivePS {
 
   PS_GET(const Vector<std::string>&, Filters)
 
-  static ProfileBuffer& Buffer(PSLockRef) { return *sInstance->mBuffer.get(); }
+  static ProfileBuffer& Buffer(PSLockRef) { return sInstance->mProfileBuffer; }
 
   static const Vector<LiveProfiledThreadData>& LiveProfiledThreads(PSLockRef) {
     return sInstance->mLiveProfiledThreads;
@@ -687,7 +705,7 @@ class ActivePS {
       LiveProfiledThreadData& thread = sInstance->mLiveProfiledThreads[i];
       if (thread.mRegisteredThread == aRegisteredThread) {
         thread.mProfiledThreadData->NotifyUnregistered(
-            sInstance->mBuffer->mRangeEnd);
+            sInstance->mProfileBuffer.BufferRangeEnd());
         MOZ_RELEASE_ASSERT(sInstance->mDeadProfiledThreads.append(
             std::move(thread.mProfiledThreadData)));
         sInstance->mLiveProfiledThreads.erase(
@@ -704,7 +722,7 @@ class ActivePS {
 #  endif
 
   static void DiscardExpiredDeadProfiledThreads(PSLockRef) {
-    uint64_t bufferRangeStart = sInstance->mBuffer->mRangeStart;
+    uint64_t bufferRangeStart = sInstance->mProfileBuffer.BufferRangeStart();
     // Discard any dead threads that were unregistered before bufferRangeStart.
     sInstance->mDeadProfiledThreads.eraseIf(
         [bufferRangeStart](
@@ -723,7 +741,7 @@ class ActivePS {
     for (size_t i = 0; i < registeredPages.length(); i++) {
       RefPtr<PageInformation>& page = registeredPages[i];
       if (page->DocShellId() == aRegisteredDocShellId) {
-        page->NotifyUnregistered(sInstance->mBuffer->mRangeEnd);
+        page->NotifyUnregistered(sInstance->mProfileBuffer.BufferRangeEnd());
         MOZ_RELEASE_ASSERT(
             sInstance->mDeadProfiledPages.append(std::move(page)));
         registeredPages.erase(&registeredPages[i--]);
@@ -732,7 +750,7 @@ class ActivePS {
   }
 
   static void DiscardExpiredPages(PSLockRef) {
-    uint64_t bufferRangeStart = sInstance->mBuffer->mRangeStart;
+    uint64_t bufferRangeStart = sInstance->mProfileBuffer.BufferRangeStart();
     // Discard any dead pages that were unregistered before
     // bufferRangeStart.
     sInstance->mDeadProfiledPages.eraseIf(
@@ -750,7 +768,7 @@ class ActivePS {
   }
 
   static void ClearExpiredExitProfiles(PSLockRef) {
-    uint64_t bufferRangeStart = sInstance->mBuffer->mRangeStart;
+    uint64_t bufferRangeStart = sInstance->mProfileBuffer.BufferRangeStart();
     // Discard exit profiles that were gathered before our buffer RangeStart.
     sInstance->mExitProfiles.eraseIf(
         [bufferRangeStart](const ExitProfile& aExitProfile) {
@@ -762,7 +780,7 @@ class ActivePS {
     ClearExpiredExitProfiles(aLock);
 
     MOZ_RELEASE_ASSERT(sInstance->mExitProfiles.append(
-        ExitProfile{aExitProfile, sInstance->mBuffer->mRangeEnd}));
+        ExitProfile{aExitProfile, sInstance->mProfileBuffer.BufferRangeEnd()}));
   }
 
   static Vector<std::string> MoveExitProfiles(PSLockRef aLock) {
@@ -802,10 +820,10 @@ class ActivePS {
   const uint32_t mGeneration;
   static uint32_t sNextGeneration;
 
-  // The maximum number of entries in mBuffer.
-  const uint32_t mCapacity;
+  // The maximum number of 8-byte entries in mProfileBuffer.
+  const PowerOfTwo32 mCapacity;
 
-  // The maximum duration of entries in mBuffer, in seconds.
+  // The maximum duration of entries in mProfileBuffer, in seconds.
   const Maybe<double> mDuration;
 
   // The interval between samples, measured in milliseconds.
@@ -817,9 +835,8 @@ class ActivePS {
   // Substrings of names of threads we want to profile.
   Vector<std::string> mFilters;
 
-  // The buffer into which all samples are recorded. Always non-null. Always
-  // used in conjunction with CorePS::m{Live,Dead}Threads.
-  const UniquePtr<ProfileBuffer> mBuffer;
+  // The buffer into which all samples are recorded.
+  ProfileBuffer mProfileBuffer;
 
   // ProfiledThreadData objects for any threads that were profiled at any point
   // during this run of the profiler:
@@ -876,6 +893,12 @@ void RacyFeatures::SetInactive() { sActiveAndFeatures = 0; }
 /* static */
 bool RacyFeatures::IsActive() { return uint32_t(sActiveAndFeatures) & Active; }
 
+/* static */
+void RacyFeatures::SetPaused() { sActiveAndFeatures |= Paused; }
+
+/* static */
+void RacyFeatures::SetUnpaused() { sActiveAndFeatures &= ~Paused; }
+
 /* static */
 bool RacyFeatures::IsActiveWithFeature(uint32_t aFeature) {
   uint32_t af = sActiveAndFeatures;  // copy it first
@@ -888,6 +911,12 @@ bool RacyFeatures::IsActiveWithoutPrivacy() {
   return (af & Active) && !(af & ProfilerFeature::Privacy);
 }
 
+/* static */
+bool RacyFeatures::IsActiveAndUnpausedWithoutPrivacy() {
+  uint32_t af = sActiveAndFeatures;  // copy it first
+  return (af & Active) && !(af & (Paused | ProfilerFeature::Privacy));
+}
+
 // Each live thread has a RegisteredThread, and we store a reference to it in
 // TLS. This class encapsulates that TLS.
 class TLSRegisteredThread {
@@ -978,8 +1007,8 @@ class Registers {
   void Clear() { memset(this, 0, sizeof(*this)); }
 
   // These fields are filled in by
-  // SamplerThread::SuspendAndSampleAndResumeThread() for periodic and
-  // backtrace samples, and by SyncPopulate() for synchronous samples.
+  // Sampler::SuspendAndSampleAndResumeThread() for periodic and backtrace
+  // samples, and by SyncPopulate() for synchronous samples.
   Address mPC;  // Instruction pointer.
   Address mSP;  // Stack pointer.
   Address mFP;  // Frame pointer.
@@ -1389,24 +1418,17 @@ static void DoNativeBacktrace(PSLockRef aLock,
 // ProfileBuffer::StreamSamplesToJSON.
 static inline void DoSharedSample(PSLockRef aLock, bool aIsSynchronous,
                                   RegisteredThread& aRegisteredThread,
-                                  const TimeStamp& aNow, const Registers& aRegs,
-                                  Maybe<uint64_t>* aLastSample,
+                                  const Registers& aRegs, uint64_t aSamplePos,
                                   ProfileBuffer& aBuffer) {
   // WARNING: this function runs within the profiler's "critical section".
 
+  MOZ_ASSERT(!aBuffer.IsThreadSafe(),
+             "Mutexes cannot be used inside this critical section");
+
   MOZ_RELEASE_ASSERT(ActivePS::Exists(aLock));
 
-  uint64_t samplePos =
-      aBuffer.AddThreadIdEntry(aRegisteredThread.Info()->ThreadId());
-  if (aLastSample) {
-    *aLastSample = Some(samplePos);
-  }
-
-  TimeDuration delta = aNow - CorePS::ProcessStartTime();
-  aBuffer.AddEntry(ProfileBufferEntry::Time(delta.ToMilliseconds()));
-
   ProfileBufferCollector collector(aBuffer, ActivePS::Features(aLock),
-                                   samplePos);
+                                   aSamplePos);
   NativeStack nativeStack;
 #  if defined(HAVE_NATIVE_UNWIND)
   if (ActivePS::FeatureStackWalk(aLock)) {
@@ -1433,29 +1455,28 @@ static void DoSyncSample(PSLockRef aLock, RegisteredThread& aRegisteredThread,
                          ProfileBuffer& aBuffer) {
   // WARNING: this function runs within the profiler's "critical section".
 
-  DoSharedSample(aLock, /* aIsSynchronous = */ true, aRegisteredThread, aNow,
-                 aRegs, /* aLastSample = */ nullptr, aBuffer);
+  uint64_t samplePos =
+      aBuffer.AddThreadIdEntry(aRegisteredThread.Info()->ThreadId());
+
+  TimeDuration delta = aNow - CorePS::ProcessStartTime();
+  aBuffer.AddEntry(ProfileBufferEntry::Time(delta.ToMilliseconds()));
+
+  DoSharedSample(aLock, /* aIsSynchronous = */ true, aRegisteredThread, aRegs,
+                 samplePos, aBuffer);
 }
 
 // Writes the components of a periodic sample to ActivePS's ProfileBuffer.
+// The ThreadId entry is already written in the main ProfileBuffer, its location
+// is `aSamplePos`, we can write the rest to `aBuffer` (which may be different).
 static void DoPeriodicSample(PSLockRef aLock,
                              RegisteredThread& aRegisteredThread,
                              ProfiledThreadData& aProfiledThreadData,
-                             const TimeStamp& aNow, const Registers& aRegs) {
+                             const Registers& aRegs, uint64_t aSamplePos,
+                             ProfileBuffer& aBuffer) {
   // WARNING: this function runs within the profiler's "critical section".
 
-  ProfileBuffer& buffer = ActivePS::Buffer(aLock);
-
-  DoSharedSample(aLock, /* aIsSynchronous = */ false, aRegisteredThread, aNow,
-                 aRegs, &aProfiledThreadData.LastSample(), buffer);
-
-  ProfilerMarkerLinkedList* pendingMarkersList =
-      aRegisteredThread.RacyRegisteredThread().GetPendingMarkers();
-  while (pendingMarkersList && pendingMarkersList->peek()) {
-    ProfilerMarker* marker = pendingMarkersList->popHead();
-    buffer.AddStoredMarker(marker);
-    buffer.AddEntry(ProfileBufferEntry::Marker(marker));
-  }
+  DoSharedSample(aLock, /* aIsSynchronous = */ false, aRegisteredThread, aRegs,
+                 aSamplePos, aBuffer);
 }
 
 // END sampling/unwinding code
@@ -1494,14 +1515,35 @@ void AppendSharedLibraries(JSONWriter& aWriter) {
 }
 
 static void StreamCategories(SpliceableJSONWriter& aWriter) {
-  // Same order as ProfilingCategory.
+  // Same order as ProfilingCategory. Format:
+  // [
+  //   {
+  //     name: "Idle",
+  //     color: "transparent",
+  //     subcategories: ["Other"],
+  //   },
+  //   {
+  //     name: "Other",
+  //     color: "grey",
+  //     subcategories: [
+  //       "JSM loading",
+  //       "Subprocess launching",
+  //       "DLL loading"
+  //     ]
+  //   },
+  //   ...
+  // ]
 
 #  define CATEGORY_JSON_BEGIN_CATEGORY(name, labelAsString, color) \
     aWriter.Start();                                               \
     aWriter.StringProperty("name", labelAsString);                 \
-    aWriter.StringProperty("color", color);
-#  define CATEGORY_JSON_SUBCATEGORY(category, name, labelAsString)
-#  define CATEGORY_JSON_END_CATEGORY aWriter.EndObject();
+    aWriter.StringProperty("color", color);                        \
+    aWriter.StartArrayProperty("subcategories");
+#  define CATEGORY_JSON_SUBCATEGORY(supercategory, name, labelAsString) \
+    aWriter.StringElement(labelAsString);
+#  define CATEGORY_JSON_END_CATEGORY \
+    aWriter.EndArray();              \
+    aWriter.EndObject();
 
   BASE_PROFILING_CATEGORY_LIST(CATEGORY_JSON_BEGIN_CATEGORY,
                                CATEGORY_JSON_SUBCATEGORY,
@@ -1519,12 +1561,12 @@ static void StreamMetaJSCustomObject(PSLockRef aLock,
                                      bool aIsShuttingDown) {
   MOZ_RELEASE_ASSERT(CorePS::Exists() && ActivePS::Exists(aLock));
 
-  aWriter.IntProperty("version", 15);
+  aWriter.IntProperty("version", 16);
 
   // The "startTime" field holds the number of milliseconds since midnight
   // January 1, 1970 GMT. This grotty code computes (Now - (Now -
   // ProcessStartTime)) to convert CorePS::ProcessStartTime() into that form.
-  TimeDuration delta = TimeStamp::Now() - CorePS::ProcessStartTime();
+  TimeDuration delta = TimeStamp::NowUnfuzzed() - CorePS::ProcessStartTime();
   aWriter.DoubleProperty(
       "startTime", MicrosecondsSince1970() / 1000.0 - delta.ToMilliseconds());
 
@@ -1582,10 +1624,19 @@ static void locked_profiler_stream_json_for_this_process(
 
   MOZ_RELEASE_ASSERT(CorePS::Exists() && ActivePS::Exists(aLock));
 
-  double collectionStart = profiler_time();
+  AUTO_PROFILER_STATS(base_locked_profiler_stream_json_for_this_process);
+
+  const double collectionStartMs = profiler_time();
 
   ProfileBuffer& buffer = ActivePS::Buffer(aLock);
 
+  // If there is a set "Window length", discard older data.
+  Maybe<double> durationS = ActivePS::Duration(aLock);
+  if (durationS.isSome()) {
+    const double durationStartMs = collectionStartMs - *durationS * 1000;
+    buffer.DiscardSamplesBeforeTime(durationStartMs);
+  }
+
   if (!aOnlyThreads) {
     // Put shared library info
     aWriter.StartArrayProperty("libs");
@@ -1606,7 +1657,6 @@ static void locked_profiler_stream_json_for_this_process(
                                         aSinceTime);
     buffer.StreamCountersToJSON(aWriter, CorePS::ProcessStartTime(),
                                 aSinceTime);
-    buffer.StreamMemoryToJSON(aWriter, CorePS::ProcessStartTime(), aSinceTime);
 
     // Lists the samples for each thread profile
     aWriter.StartArrayProperty("threads");
@@ -1633,15 +1683,15 @@ static void locked_profiler_stream_json_for_this_process(
     aWriter.EndArray();
   }
 
-  double collectionEnd = profiler_time();
+  const double collectionEndMs = profiler_time();
 
   // Record timestamps for the collection into the buffer, so that consumers
   // know why we didn't collect any samples for its duration.
   // We put these entries into the buffer after we've collected the profile,
   // so they'll be visible for the *next* profile collection (if they haven't
   // been overwritten due to buffer wraparound by then).
-  buffer.AddEntry(ProfileBufferEntry::CollectionStart(collectionStart));
-  buffer.AddEntry(ProfileBufferEntry::CollectionEnd(collectionEnd));
+  buffer.AddEntry(ProfileBufferEntry::CollectionStart(collectionStartMs));
+  buffer.AddEntry(ProfileBufferEntry::CollectionEnd(collectionEndMs));
 }
 
 bool profiler_stream_json_for_this_process(SpliceableJSONWriter& aWriter,
@@ -1702,7 +1752,8 @@ static void PrintUsageThenExit(int aExitCode) {
       "  '..._VERBOSE_LOGGING' (most verbose)\n"
       "\n"
       "  MOZ_BASE_PROFILER_STARTUP\n"
-      "  If set to any value, starts the profiler immediately on start-up.\n"
+      "  If set to any value other than '' or '0'/'N'/'n', starts the\n"
+      "  profiler immediately on start-up.\n"
       "  Useful if you want profile code that runs very early.\n"
       "\n"
       "  MOZ_BASE_PROFILER_STARTUP_ENTRIES=<1..>\n"
@@ -1711,7 +1762,7 @@ static void PrintUsageThenExit(int aExitCode) {
       "  first started.\n"
       "  If unset, the platform default is used:\n"
       "  %u entries per process, or %u when MOZ_BASE_PROFILER_STARTUP is set.\n"
-      "  (%zu bytes per entry -> %zu or %zu total bytes per process)\n"
+      "  (8 bytes per entry -> %u or %u total bytes per process)\n"
       "\n"
       "  MOZ_BASE_PROFILER_STARTUP_DURATION=<1..>\n"
       "  If MOZ_BASE_PROFILER_STARTUP is set, specifies the maximum life time\n"
@@ -1740,11 +1791,10 @@ static void PrintUsageThenExit(int aExitCode) {
       "    Features: (x=unavailable, D/d=default/unavailable,\n"
       "               S/s=MOZ_BASE_PROFILER_STARTUP extra "
       "default/unavailable)\n",
-      unsigned(BASE_PROFILER_DEFAULT_ENTRIES),
-      unsigned(BASE_PROFILER_DEFAULT_STARTUP_ENTRIES),
-      sizeof(ProfileBufferEntry),
-      sizeof(ProfileBufferEntry) * BASE_PROFILER_DEFAULT_ENTRIES,
-      sizeof(ProfileBufferEntry) * BASE_PROFILER_DEFAULT_STARTUP_ENTRIES);
+      unsigned(BASE_PROFILER_DEFAULT_ENTRIES.Value()),
+      unsigned(BASE_PROFILER_DEFAULT_STARTUP_ENTRIES.Value()),
+      unsigned(BASE_PROFILER_DEFAULT_ENTRIES.Value() * 8),
+      unsigned(BASE_PROFILER_DEFAULT_STARTUP_ENTRIES.Value() * 8));
 
 #  define PRINT_FEATURE(n_, str_, Name_, desc_)                             \
     printf("    %c %5u: \"%s\" (%s)\n",                                     \
@@ -1825,7 +1875,7 @@ class Sampler {
   template <typename Func>
   void SuspendAndSampleAndResumeThread(
       PSLockRef aLock, const RegisteredThread& aRegisteredThread,
-      const Func& aProcessRegs);
+      const TimeStamp& aNow, const Func& aProcessRegs);
 
  private:
 #  if defined(GP_OS_linux) || defined(GP_OS_android)
@@ -1858,7 +1908,7 @@ class Sampler {
 // active. It periodically runs through all registered threads, finds those
 // that should be sampled, then pauses and samples them.
 
-class SamplerThread : public Sampler {
+class SamplerThread {
  public:
   // Creates a sampler thread, but doesn't start it.
   SamplerThread(PSLockRef aLock, uint32_t aActivityGeneration,
@@ -1876,6 +1926,9 @@ class SamplerThread : public Sampler {
   // Best effort timing.
   void SleepMicro(uint32_t aMicroseconds);
 
+  // The sampler used to suspend and sample threads.
+  Sampler mSampler;
+
   // The activity generation, for detecting when the sampler thread must stop.
   const uint32_t mActivityGeneration;
 
@@ -1907,16 +1960,40 @@ void SamplerThread::Run() {
   // TODO: If possible, name this thread later on, after NSPR becomes available.
   // PR_SetCurrentThreadName("SamplerThread");
 
+  // Features won't change during this SamplerThread's lifetime, so we can
+  // determine now whether stack sampling is required.
+  const bool noStackSampling = []() {
+    PSAutoLock lock;
+    if (!ActivePS::Exists(lock)) {
+      // If there is no active profiler, it doesn't matter what we return,
+      // because this thread will exit before any stack sampling is attempted.
+      return false;
+    }
+    return ActivePS::FeatureNoStackSampling(lock);
+  }();
+
+  // Use local BlocksRingBuffer&ProfileBuffer to capture the stack.
+  // (This is to avoid touching the CorePS::BlocksRingBuffer lock while
+  // a thread is suspended, because that thread could be working with
+  // the CorePS::BlocksRingBuffer as well.)
+  BlocksRingBuffer localBlocksRingBuffer(
+      BlocksRingBuffer::ThreadSafety::WithoutMutex);
+  ProfileBuffer localProfileBuffer(localBlocksRingBuffer,
+                                   MakePowerOfTwo32<65536>());
+
+  // Will be kept between collections, to know what each collection does.
+  auto previousState = localBlocksRingBuffer.GetState();
+
   // This will be positive if we are running behind schedule (sampling less
   // frequently than desired) and negative if we are ahead of schedule.
   TimeDuration lastSleepOvershoot = 0;
-  TimeStamp sampleStart = TimeStamp::Now();
+  TimeStamp sampleStart = TimeStamp::NowUnfuzzed();
 
   while (true) {
     // This scope is for |lock|. It ends before we sleep below.
     {
       PSAutoLock lock;
-      TimeStamp lockAcquired = TimeStamp::Now();
+      TimeStamp lockAcquired = TimeStamp::NowUnfuzzed();
 
       if (!ActivePS::Exists(lock)) {
         return;
@@ -1931,19 +2008,14 @@ void SamplerThread::Run() {
 
       ActivePS::ClearExpiredExitProfiles(lock);
 
-      ActivePS::Buffer(lock).DeleteExpiredStoredMarkers();
-      TimeStamp expiredMarkersCleaned = TimeStamp::Now();
+      TimeStamp expiredMarkersCleaned = TimeStamp::NowUnfuzzed();
 
       if (!ActivePS::IsPaused(lock)) {
-        const Vector<LiveProfiledThreadData>& liveThreads =
-            ActivePS::LiveProfiledThreads(lock);
-
         TimeDuration delta = sampleStart - CorePS::ProcessStartTime();
         ProfileBuffer& buffer = ActivePS::Buffer(lock);
 
         // handle per-process generic counters
         const Vector<BaseProfilerCount*>& counters = CorePS::Counters(lock);
-        TimeStamp now = TimeStamp::Now();
         for (auto& counter : counters) {
           // create Buffer entries for each counter
           buffer.AddEntry(ProfileBufferEntry::CounterId(counter));
@@ -1961,33 +2033,75 @@ void SamplerThread::Run() {
             buffer.AddEntry(ProfileBufferEntry::Number(number));
           }
         }
-        TimeStamp countersSampled = TimeStamp::Now();
+        TimeStamp countersSampled = TimeStamp::NowUnfuzzed();
 
-        for (auto& thread : liveThreads) {
-          RegisteredThread* registeredThread = thread.mRegisteredThread;
-          ProfiledThreadData* profiledThreadData =
-              thread.mProfiledThreadData.get();
-          RefPtr<ThreadInfo> info = registeredThread->Info();
+        if (!noStackSampling) {
+          const Vector<LiveProfiledThreadData>& liveThreads =
+              ActivePS::LiveProfiledThreads(lock);
 
-          // If the thread is asleep and has been sampled before in the same
-          // sleep episode, find and copy the previous sample, as that's
-          // cheaper than taking a new sample.
-          if (registeredThread->RacyRegisteredThread()
-                  .CanDuplicateLastSampleDueToSleep()) {
-            bool dup_ok = ActivePS::Buffer(lock).DuplicateLastSample(
-                info->ThreadId(), CorePS::ProcessStartTime(),
-                profiledThreadData->LastSample());
-            if (dup_ok) {
-              continue;
+          for (auto& thread : liveThreads) {
+            RegisteredThread* registeredThread = thread.mRegisteredThread;
+            ProfiledThreadData* profiledThreadData =
+                thread.mProfiledThreadData.get();
+            RefPtr<ThreadInfo> info = registeredThread->Info();
+
+            // If the thread is asleep and has been sampled before in the same
+            // sleep episode, find and copy the previous sample, as that's
+            // cheaper than taking a new sample.
+            if (registeredThread->RacyRegisteredThread()
+                    .CanDuplicateLastSampleDueToSleep()) {
+              bool dup_ok = ActivePS::Buffer(lock).DuplicateLastSample(
+                  info->ThreadId(), CorePS::ProcessStartTime(),
+                  profiledThreadData->LastSample());
+              if (dup_ok) {
+                continue;
+              }
             }
-          }
 
-          now = TimeStamp::Now();
-          SuspendAndSampleAndResumeThread(
-              lock, *registeredThread, [&](const Registers& aRegs) {
-                DoPeriodicSample(lock, *registeredThread, *profiledThreadData,
-                                 now, aRegs);
-              });
+            AUTO_PROFILER_STATS(base_SamplerThread_Run_DoPeriodicSample);
+
+            TimeStamp now = TimeStamp::NowUnfuzzed();
+
+            // Add the thread ID now, so we know its position in the main
+            // buffer, which is used by some JS data. (DoPeriodicSample only
+            // knows about the temporary local buffer.)
+            uint64_t samplePos =
+                buffer.AddThreadIdEntry(registeredThread->Info()->ThreadId());
+            profiledThreadData->LastSample() = Some(samplePos);
+
+            // Also add the time, so it's always there after the thread ID, as
+            // expected by the parser. (Other stack data is optional.)
+            TimeDuration delta = now - CorePS::ProcessStartTime();
+            buffer.AddEntry(ProfileBufferEntry::Time(delta.ToMilliseconds()));
+
+            mSampler.SuspendAndSampleAndResumeThread(
+                lock, *registeredThread, now,
+                [&](const Registers& aRegs, const TimeStamp& aNow) {
+                  DoPeriodicSample(lock, *registeredThread, *profiledThreadData,
+                                   aRegs, samplePos, localProfileBuffer);
+                });
+
+            // If data is complete, copy it into the global buffer.
+            auto state = localBlocksRingBuffer.GetState();
+            if (state.mClearedBlockCount != previousState.mClearedBlockCount) {
+              LOG("Stack sample too big for local storage, needed %u bytes",
+                  unsigned(state.mRangeEnd.ConvertToU64() -
+                           previousState.mRangeEnd.ConvertToU64()));
+            } else if (state.mRangeEnd.ConvertToU64() -
+                           previousState.mRangeEnd.ConvertToU64() >=
+                       CorePS::CoreBlocksRingBuffer().BufferLength()->Value()) {
+              LOG("Stack sample too big for profiler storage, needed %u bytes",
+                  unsigned(state.mRangeEnd.ConvertToU64() -
+                           previousState.mRangeEnd.ConvertToU64()));
+            } else {
+              CorePS::CoreBlocksRingBuffer().AppendContents(
+                  localBlocksRingBuffer);
+            }
+
+            // Clean up for the next run.
+            localBlocksRingBuffer.Clear();
+            previousState = localBlocksRingBuffer.GetState();
+          }
         }
 
 #  if defined(USE_LUL_STACKWALK)
@@ -1998,26 +2112,12 @@ void SamplerThread::Run() {
         // SuspendAndSampleAndResumeThread, which is why it is done here.
         CorePS::Lul(lock)->MaybeShowStats();
 #  endif
-        TimeStamp threadsSampled = TimeStamp::Now();
+        TimeStamp threadsSampled = TimeStamp::NowUnfuzzed();
 
-        buffer.AddEntry(
-            ProfileBufferEntry::ProfilerOverheadTime(delta.ToMilliseconds()));
-        buffer.AddEntry(ProfileBufferEntry::ProfilerOverheadDuration(
-            (lockAcquired - sampleStart).ToMilliseconds()));
-        buffer.AddEntry(ProfileBufferEntry::ProfilerOverheadDuration(
-            (expiredMarkersCleaned - lockAcquired).ToMilliseconds()));
-        buffer.AddEntry(ProfileBufferEntry::ProfilerOverheadDuration(
-            (countersSampled - expiredMarkersCleaned).ToMilliseconds()));
-        buffer.AddEntry(ProfileBufferEntry::ProfilerOverheadDuration(
-            (threadsSampled - countersSampled).ToMilliseconds()));
-      }
-
-      Maybe<double> duration = ActivePS::Duration(lock);
-      if (duration) {
-        ActivePS::Buffer(lock).DiscardSamplesBeforeTime(
-            (TimeStamp::Now() - TimeDuration::FromSeconds(*duration) -
-             CorePS::ProcessStartTime())
-                .ToMilliseconds());
+        buffer.CollectOverheadStats(delta, lockAcquired - sampleStart,
+                                    expiredMarkersCleaned - lockAcquired,
+                                    countersSampled - expiredMarkersCleaned,
+                                    threadsSampled - countersSampled);
       }
     }
     // gPSMutex is not held after this point.
@@ -2029,12 +2129,12 @@ void SamplerThread::Run() {
     // actual sleep intervals.
     TimeStamp targetSleepEndTime =
         sampleStart + TimeDuration::FromMicroseconds(mIntervalMicroseconds);
-    TimeStamp beforeSleep = TimeStamp::Now();
+    TimeStamp beforeSleep = TimeStamp::NowUnfuzzed();
     TimeDuration targetSleepDuration = targetSleepEndTime - beforeSleep;
     double sleepTime = std::max(
         0.0, (targetSleepDuration - lastSleepOvershoot).ToMicroseconds());
     SleepMicro(static_cast<uint32_t>(sleepTime));
-    sampleStart = TimeStamp::Now();
+    sampleStart = TimeStamp::NowUnfuzzed();
     lastSleepOvershoot =
         sampleStart - (beforeSleep + TimeDuration::FromMicroseconds(sleepTime));
   }
@@ -2152,7 +2252,7 @@ static ProfilingStack* locked_register_thread(PSLockRef aLock,
   return profilingStack;
 }
 
-static void locked_profiler_start(PSLockRef aLock, uint32_t aCapacity,
+static void locked_profiler_start(PSLockRef aLock, PowerOfTwo32 aCapacity,
                                   double aInterval, uint32_t aFeatures,
                                   const char** aFilters, uint32_t aFilterCount,
                                   const Maybe<double>& aDuration);
@@ -2199,7 +2299,7 @@ void profiler_init(void* aStackTop) {
   Vector<const char*> filters;
   MOZ_RELEASE_ASSERT(filters.append(kMainThreadName));
 
-  uint32_t capacity = BASE_PROFILER_DEFAULT_ENTRIES;
+  PowerOfTwo32 capacity = BASE_PROFILER_DEFAULT_ENTRIES;
   Maybe<double> duration = Nothing();
   double interval = BASE_PROFILER_DEFAULT_INTERVAL;
 
@@ -2222,7 +2322,10 @@ void profiler_init(void* aStackTop) {
     // created on demand at the first call to PlatformStart().
 
     const char* startupEnv = getenv("MOZ_BASE_PROFILER_STARTUP");
-    if (!startupEnv || startupEnv[0] == '\0') {
+    if (!startupEnv || startupEnv[0] == '\0' ||
+        ((startupEnv[0] == '0' || startupEnv[0] == 'N' ||
+          startupEnv[0] == 'n') &&
+         startupEnv[1] == '\0')) {
       return;
     }
 
@@ -2236,12 +2339,14 @@ void profiler_init(void* aStackTop) {
       errno = 0;
       long capacityLong = strtol(startupCapacity, nullptr, 10);
       // `long` could be 32 or 64 bits, so we force a 64-bit comparison with
-      // the maximum 32-bit unsigned number.
+      // the maximum 32-bit signed number (as more than that is clamped down to
+      // 2^31 anyway).
       if (errno == 0 && capacityLong > 0 &&
           static_cast<uint64_t>(capacityLong) <=
-              static_cast<uint64_t>(UINT32_MAX)) {
-        capacity = static_cast<uint32_t>(capacityLong);
-        LOG("- MOZ_BASE_PROFILER_STARTUP_ENTRIES = %u", unsigned(capacity));
+              static_cast<uint64_t>(INT32_MAX)) {
+        capacity = PowerOfTwo32(static_cast<uint32_t>(capacityLong));
+        LOG("- MOZ_BASE_PROFILER_STARTUP_ENTRIES = %u",
+            unsigned(capacity.Value()));
       } else {
         LOG("- MOZ_BASE_PROFILER_STARTUP_ENTRIES not a valid integer: %s",
             startupCapacity);
@@ -2326,12 +2431,10 @@ void profiler_init(void* aStackTop) {
 
   // TODO: Install memory counter if it is possible from mozglue.
   // #if defined(MOZ_REPLACE_MALLOC) && defined(MOZ_PROFILER_MEMORY)
-  //   if (ProfilerFeature::HasMemory(features)) {
-  //     // start counting memory allocations (outside of lock because this may
-  //     call
-  //     // profiler_add_sampled_counter which would attempt to take the lock.)
-  //     mozilla::profiler::install_memory_counter(true);
-  //   }
+  //   // start counting memory allocations (outside of lock because this may
+  //   call
+  //   // profiler_add_sampled_counter which would attempt to take the lock.)
+  //   mozilla::profiler::install_memory_counter(true);
   // #endif
 }
 
@@ -2462,7 +2565,7 @@ void profiler_get_start_params(int* aCapacity, Maybe<double>* aDuration,
     return;
   }
 
-  *aCapacity = ActivePS::Capacity(lock);
+  *aCapacity = ActivePS::Capacity(lock).Value();
   *aDuration = ActivePS::Duration(lock);
   *aInterval = ActivePS::Interval(lock);
   *aFeatures = ActivePS::Features(lock);
@@ -2486,7 +2589,8 @@ void GetProfilerEnvVarsForChildProcess(
   }
 
   aSetEnv("MOZ_BASE_PROFILER_STARTUP", "1");
-  auto capacityString = Smprintf("%d", ActivePS::Capacity(lock));
+  auto capacityString =
+      Smprintf("%u", unsigned(ActivePS::Capacity(lock).Value()));
   aSetEnv("MOZ_BASE_PROFILER_STARTUP_ENTRIES", capacityString.get());
 
   // Use AppendFloat instead of Smprintf with %f because the decimal
@@ -2588,18 +2692,34 @@ Maybe<ProfilerBufferInfo> profiler_get_buffer_info() {
     return Nothing();
   }
 
-  return Some(ProfilerBufferInfo{ActivePS::Buffer(lock).mRangeStart,
-                                 ActivePS::Buffer(lock).mRangeEnd,
-                                 ActivePS::Capacity(lock)});
+  return Some(ActivePS::Buffer(lock).GetProfilerBufferInfo());
 }
 
-static void locked_profiler_start(PSLockRef aLock, uint32_t aCapacity,
+// This basically duplicates AutoProfilerLabel's constructor.
+static void* MozGlueBaseLabelEnter(const char* aLabel,
+                                   const char* aDynamicString, void* aSp) {
+  ProfilingStack* profilingStack = AutoProfilerLabel::sProfilingStack.get();
+  if (profilingStack) {
+    profilingStack->pushLabelFrame(aLabel, aDynamicString, aSp,
+                                   ProfilingCategoryPair::OTHER);
+  }
+  return profilingStack;
+}
+
+// This basically duplicates AutoProfilerLabel's destructor.
+static void MozGlueBaseLabelExit(void* sProfilingStack) {
+  if (sProfilingStack) {
+    reinterpret_cast<ProfilingStack*>(sProfilingStack)->pop();
+  }
+}
+
+static void locked_profiler_start(PSLockRef aLock, PowerOfTwo32 aCapacity,
                                   double aInterval, uint32_t aFeatures,
                                   const char** aFilters, uint32_t aFilterCount,
                                   const Maybe<double>& aDuration) {
   if (LOG_TEST) {
     LOG("locked_profiler_start");
-    LOG("- capacity  = %d", aCapacity);
+    LOG("- capacity  = %d", int(aCapacity.Value()));
     LOG("- duration  = %.2f", aDuration ? *aDuration : -1);
     LOG("- interval = %.2f", aInterval);
 
@@ -2624,7 +2744,11 @@ static void locked_profiler_start(PSLockRef aLock, uint32_t aCapacity,
 #  endif
 
   // Fall back to the default values if the passed-in values are unreasonable.
-  uint32_t capacity = aCapacity > 0 ? aCapacity : BASE_PROFILER_DEFAULT_ENTRIES;
+  // Less than 8192 entries (65536 bytes) may not be enough for the most complex
+  // stack, so we should be able to store at least one full stack.
+  // TODO: Review magic numbers.
+  PowerOfTwo32 capacity =
+      (aCapacity.Value() >= 8192u) ? aCapacity : BASE_PROFILER_DEFAULT_ENTRIES;
   Maybe<double> duration = aDuration;
 
   if (aDuration && *aDuration <= 0) {
@@ -2649,13 +2773,16 @@ static void locked_profiler_start(PSLockRef aLock, uint32_t aCapacity,
     }
   }
 
+  // Setup support for pushing/popping labels in mozglue.
+  RegisterProfilerLabelEnterExit(MozGlueBaseLabelEnter, MozGlueBaseLabelExit);
+
   // At the very end, set up RacyFeatures.
   RacyFeatures::SetActive(ActivePS::Features(aLock));
 }
 
-void profiler_start(uint32_t aCapacity, double aInterval, uint32_t aFeatures,
-                    const char** aFilters, uint32_t aFilterCount,
-                    const Maybe<double>& aDuration) {
+void profiler_start(PowerOfTwo32 aCapacity, double aInterval,
+                    uint32_t aFeatures, const char** aFilters,
+                    uint32_t aFilterCount, const Maybe<double>& aDuration) {
   LOG("profiler_start");
 
   SamplerThread* samplerThread = nullptr;
@@ -2678,12 +2805,10 @@ void profiler_start(uint32_t aCapacity, double aInterval, uint32_t aFeatures,
 
   // TODO: Install memory counter if it is possible from mozglue.
   // #if defined(MOZ_REPLACE_MALLOC) && defined(MOZ_PROFILER_MEMORY)
-  //   if (ProfilerFeature::HasMemory(aFeatures)) {
-  //     // start counting memory allocations (outside of lock because this may
-  //     call
-  //     // profiler_add_sampled_counter which would attempt to take the lock.)
-  //     mozilla::profiler::install_memory_counter(true);
-  //   }
+  //   // start counting memory allocations (outside of lock because this may
+  //   call
+  //   // profiler_add_sampled_counter which would attempt to take the lock.)
+  //   mozilla::profiler::install_memory_counter(true);
   // #endif
 
   // We do these operations with gPSMutex unlocked. The comments in
@@ -2693,7 +2818,7 @@ void profiler_start(uint32_t aCapacity, double aInterval, uint32_t aFeatures,
   }
 }
 
-void profiler_ensure_started(uint32_t aCapacity, double aInterval,
+void profiler_ensure_started(PowerOfTwo32 aCapacity, double aInterval,
                              uint32_t aFeatures, const char** aFilters,
                              uint32_t aFilterCount,
                              const Maybe<double>& aDuration) {
@@ -2715,13 +2840,6 @@ void profiler_ensure_started(uint32_t aCapacity, double aInterval,
                             aFilters, aFilterCount)) {
         // Stop and restart with different settings.
         samplerThread = locked_profiler_stop(lock);
-        // TODO: Uninstall memory counter if it is possible from mozglue.
-        // #if defined(MOZ_REPLACE_MALLOC) && defined(MOZ_PROFILER_MEMORY)
-        //         if (!ProfilerFeature::HasMemory(aFeatures)) {
-        //           // Ensure we don't record memory measurements anymore (if
-        //           we were). mozilla::profiler::install_memory_counter(false);
-        //         }
-        // #endif
         locked_profiler_start(lock, aCapacity, aInterval, aFeatures, aFilters,
                               aFilterCount, aDuration);
         // startedProfiler = true; (See TODO below)
@@ -2736,12 +2854,10 @@ void profiler_ensure_started(uint32_t aCapacity, double aInterval,
 
   // TODO: Install memory counter if it is possible from mozglue.
   // #if defined(MOZ_REPLACE_MALLOC) && defined(MOZ_PROFILER_MEMORY)
-  //   if (startedProfiler && ProfilerFeature::HasMemory(aFeatures)) {
-  //     // start counting memory allocations (outside of lock because this may
-  //     // call profiler_add_sampled_counter which would attempt to take the
-  //     // lock.)
-  //     mozilla::profiler::install_memory_counter(true);
-  //   }
+  //   // start counting memory allocations (outside of lock because this may
+  //   // call profiler_add_sampled_counter which would attempt to take the
+  //   // lock.)
+  //   mozilla::profiler::install_memory_counter(true);
   // #endif
 
   // We do these operations with gPSMutex unlocked. The comments in
@@ -2764,6 +2880,9 @@ static MOZ_MUST_USE SamplerThread* locked_profiler_stop(PSLockRef aLock) {
   //   mozilla::profiler::install_memory_counter(false);
   // #endif
 
+  // Remove support for pushing/popping labels in mozglue.
+  RegisterProfilerLabelEnterExit(nullptr, nullptr);
+
   // Stop sampling live threads.
   const Vector<LiveProfiledThreadData>& liveProfiledThreads =
       ActivePS::LiveProfiledThreads(aLock);
@@ -2833,6 +2952,7 @@ void profiler_pause() {
       return;
     }
 
+    RacyFeatures::SetPaused();
     ActivePS::SetIsPaused(lock, true);
     ActivePS::Buffer(lock).AddEntry(ProfileBufferEntry::Pause(profiler_time()));
   }
@@ -2853,6 +2973,7 @@ void profiler_resume() {
     ActivePS::Buffer(lock).AddEntry(
         ProfileBufferEntry::Resume(profiler_time()));
     ActivePS::SetIsPaused(lock, false);
+    RacyFeatures::SetUnpaused();
   }
 }
 
@@ -3042,7 +3163,7 @@ bool profiler_thread_is_sleeping() {
 double profiler_time() {
   MOZ_RELEASE_ASSERT(CorePS::Exists());
 
-  TimeDuration delta = TimeStamp::Now() - CorePS::ProcessStartTime();
+  TimeDuration delta = TimeStamp::NowUnfuzzed() - CorePS::ProcessStartTime();
   return delta.ToMilliseconds();
 }
 
@@ -3064,7 +3185,7 @@ UniqueProfilerBacktrace profiler_get_backtrace() {
 
   int tid = profiler_current_thread_id();
 
-  TimeStamp now = TimeStamp::Now();
+  TimeStamp now = TimeStamp::NowUnfuzzed();
 
   Registers regs;
 #  if defined(HAVE_NATIVE_UNWIND)
@@ -3073,30 +3194,35 @@ UniqueProfilerBacktrace profiler_get_backtrace() {
   regs.Clear();
 #  endif
 
-  // 1000 should be plenty for a single backtrace.
-  auto buffer = MakeUnique<ProfileBuffer>(1000);
+  // 65536 bytes should be plenty for a single backtrace.
+  auto bufferManager = MakeUnique<BlocksRingBuffer>(
+      BlocksRingBuffer::ThreadSafety::WithoutMutex);
+  auto buffer =
+      MakeUnique<ProfileBuffer>(*bufferManager, MakePowerOfTwo32<65536>());
 
   DoSyncSample(lock, *registeredThread, now, regs, *buffer.get());
 
-  return UniqueProfilerBacktrace(
-      new ProfilerBacktrace("SyncProfile", tid, std::move(buffer)));
+  return UniqueProfilerBacktrace(new ProfilerBacktrace(
+      "SyncProfile", tid, std::move(bufferManager), std::move(buffer)));
 }
 
 void ProfilerBacktraceDestructor::operator()(ProfilerBacktrace* aBacktrace) {
   delete aBacktrace;
 }
 
-static void racy_profiler_add_marker(
-    const char* aMarkerName, ProfilingCategoryPair aCategoryPair,
-    UniquePtr<ProfilerMarkerPayload> aPayload) {
+static void racy_profiler_add_marker(const char* aMarkerName,
+                                     ProfilingCategoryPair aCategoryPair,
+                                     const ProfilerMarkerPayload* aPayload) {
   MOZ_RELEASE_ASSERT(CorePS::Exists());
 
-  // We don't assert that RacyFeatures::IsActiveWithoutPrivacy() or
-  // RacyRegisteredThread::IsBeingProfiled() is true here, because it's
-  // possible that the result has changed since we tested it in the caller.
-  //
-  // Because of this imprecision it's possible to miss a marker or record one
-  // we shouldn't. Either way is not a big deal.
+  // This function is hot enough that we use RacyFeatures, not ActivePS.
+  if (!profiler_can_accept_markers()) {
+    return;
+  }
+
+  // Note that it's possible that the above test would change again before we
+  // actually record the marker. Because of this imprecision it's possible to
+  // miss a marker or record one we shouldn't. Either way is not a big deal.
 
   RacyRegisteredThread* racyRegisteredThread =
       TLSRegisteredThread::RacyRegisteredThread();
@@ -3106,34 +3232,30 @@ static void racy_profiler_add_marker(
 
   TimeStamp origin = (aPayload && !aPayload->GetStartTime().IsNull())
                          ? aPayload->GetStartTime()
-                         : TimeStamp::Now();
+                         : TimeStamp::NowUnfuzzed();
   TimeDuration delta = origin - CorePS::ProcessStartTime();
-  racyRegisteredThread->AddPendingMarker(
-      aMarkerName, aCategoryPair, std::move(aPayload), delta.ToMilliseconds());
+  CorePS::CoreBlocksRingBuffer().PutObjects(
+      ProfileBufferEntry::Kind::MarkerData, racyRegisteredThread->ThreadId(),
+      WrapBlocksRingBufferUnownedCString(aMarkerName),
+      static_cast<uint32_t>(aCategoryPair), aPayload, delta.ToMilliseconds());
 }
 
 void profiler_add_marker(const char* aMarkerName,
                          ProfilingCategoryPair aCategoryPair,
-                         UniquePtr<ProfilerMarkerPayload> aPayload) {
-  MOZ_RELEASE_ASSERT(CorePS::Exists());
-
-  // This function is hot enough that we use RacyFeatures, not ActivePS.
-  if (!RacyFeatures::IsActiveWithoutPrivacy()) {
-    return;
-  }
-
-  racy_profiler_add_marker(aMarkerName, aCategoryPair, std::move(aPayload));
+                         const ProfilerMarkerPayload& aPayload) {
+  racy_profiler_add_marker(aMarkerName, aCategoryPair, &aPayload);
 }
 
 void profiler_add_marker(const char* aMarkerName,
                          ProfilingCategoryPair aCategoryPair) {
-  profiler_add_marker(aMarkerName, aCategoryPair, nullptr);
+  racy_profiler_add_marker(aMarkerName, aCategoryPair, nullptr);
 }
 
 // This is a simplified version of profiler_add_marker that can be easily passed
 // into the JS engine.
 void profiler_add_js_marker(const char* aMarkerName) {
-  profiler_add_marker(aMarkerName, ProfilingCategoryPair::JS, nullptr);
+  AUTO_PROFILER_STATS(base_add_marker);
+  profiler_add_marker(aMarkerName, ProfilingCategoryPair::JS);
 }
 
 // This logic needs to add a marker for a different thread, so we actually need
@@ -3144,39 +3266,41 @@ void profiler_add_marker_for_thread(int aThreadId,
                                     UniquePtr<ProfilerMarkerPayload> aPayload) {
   MOZ_RELEASE_ASSERT(CorePS::Exists());
 
-  PSAutoLock lock;
-  if (!ActivePS::Exists(lock)) {
+  if (!profiler_can_accept_markers()) {
     return;
   }
 
-  // Create the ProfilerMarker which we're going to store.
-  TimeStamp origin = (aPayload && !aPayload->GetStartTime().IsNull())
-                         ? aPayload->GetStartTime()
-                         : TimeStamp::Now();
-  TimeDuration delta = origin - CorePS::ProcessStartTime();
-  ProfilerMarker* marker =
-      new ProfilerMarker(aMarkerName, aCategoryPair, aThreadId,
-                         std::move(aPayload), delta.ToMilliseconds());
-
 #  ifdef DEBUG
-  // Assert that our thread ID makes sense
-  bool realThread = false;
-  const Vector<UniquePtr<RegisteredThread>>& registeredThreads =
-      CorePS::RegisteredThreads(lock);
-  for (auto& thread : registeredThreads) {
-    RefPtr<ThreadInfo> info = thread->Info();
-    if (info->ThreadId() == aThreadId) {
-      realThread = true;
-      break;
+  {
+    PSAutoLock lock;
+    if (!ActivePS::Exists(lock)) {
+      return;
     }
+
+    // Assert that our thread ID makes sense
+    bool realThread = false;
+    const Vector<UniquePtr<RegisteredThread>>& registeredThreads =
+        CorePS::RegisteredThreads(lock);
+    for (auto& thread : registeredThreads) {
+      RefPtr<ThreadInfo> info = thread->Info();
+      if (info->ThreadId() == aThreadId) {
+        realThread = true;
+        break;
+      }
+    }
+    MOZ_ASSERT(realThread, "Invalid thread id");
   }
-  MOZ_ASSERT(realThread, "Invalid thread id");
 #  endif
 
   // Insert the marker into the buffer
-  ProfileBuffer& buffer = ActivePS::Buffer(lock);
-  buffer.AddStoredMarker(marker);
-  buffer.AddEntry(ProfileBufferEntry::Marker(marker));
+  TimeStamp origin = (aPayload && !aPayload->GetStartTime().IsNull())
+                         ? aPayload->GetStartTime()
+                         : TimeStamp::NowUnfuzzed();
+  TimeDuration delta = origin - CorePS::ProcessStartTime();
+  CorePS::CoreBlocksRingBuffer().PutObjects(
+      ProfileBufferEntry::Kind::MarkerData, aThreadId,
+      WrapBlocksRingBufferUnownedCString(aMarkerName),
+      static_cast<uint32_t>(aCategoryPair), aPayload, delta.ToMilliseconds());
 }
 
 void profiler_tracing(const char* aCategoryString, const char* aMarkerName,
@@ -3188,13 +3312,14 @@ void profiler_tracing(const char* aCategoryString, const char* aMarkerName,
   VTUNE_TRACING(aMarkerName, aKind);
 
   // This function is hot enough that we use RacyFeatures, notActivePS.
-  if (!RacyFeatures::IsActiveWithoutPrivacy()) {
+  if (!profiler_can_accept_markers()) {
     return;
   }
 
-  auto payload = MakeUnique<TracingMarkerPayload>(
-      aCategoryString, aKind, aDocShellId, aDocShellHistoryId);
-  racy_profiler_add_marker(aMarkerName, aCategoryPair, std::move(payload));
+  AUTO_PROFILER_STATS(base_add_marker_with_TracingMarkerPayload);
+  profiler_add_marker(aMarkerName, aCategoryPair,
+                      TracingMarkerPayload(aCategoryString, aKind, aDocShellId,
+                                           aDocShellHistoryId));
 }
 
 void profiler_tracing(const char* aCategoryString, const char* aMarkerName,
@@ -3207,14 +3332,15 @@ void profiler_tracing(const char* aCategoryString, const char* aMarkerName,
   VTUNE_TRACING(aMarkerName, aKind);
 
   // This function is hot enough that we use RacyFeatures, notActivePS.
-  if (!RacyFeatures::IsActiveWithoutPrivacy()) {
+  if (!profiler_can_accept_markers()) {
     return;
   }
 
-  auto payload =
-      MakeUnique<TracingMarkerPayload>(aCategoryString, aKind, aDocShellId,
-                                       aDocShellHistoryId, std::move(aCause));
-  racy_profiler_add_marker(aMarkerName, aCategoryPair, std::move(payload));
+  AUTO_PROFILER_STATS(base_add_marker_with_TracingMarkerPayload);
+  profiler_add_marker(
+      aMarkerName, aCategoryPair,
+      TracingMarkerPayload(aCategoryString, aKind, aDocShellId,
+                           aDocShellHistoryId, std::move(aCause)));
 }
 
 void profiler_add_text_marker(const char* aMarkerName, const std::string& aText,
@@ -3224,10 +3350,11 @@ void profiler_add_text_marker(const char* aMarkerName, const std::string& aText,
                               const Maybe<std::string>& aDocShellId,
                               const Maybe<uint32_t>& aDocShellHistoryId,
                               UniqueProfilerBacktrace aCause) {
+  AUTO_PROFILER_STATS(base_add_marker_with_TextMarkerPayload);
   profiler_add_marker(
       aMarkerName, aCategoryPair,
-      MakeUnique<TextMarkerPayload>(aText, aStartTime, aEndTime, aDocShellId,
-                                    aDocShellHistoryId, std::move(aCause)));
+      TextMarkerPayload(aText, aStartTime, aEndTime, aDocShellId,
+                        aDocShellHistoryId, std::move(aCause)));
 }
 
 // NOTE: aCollector's methods will be called while the target thread is paused.
@@ -3255,10 +3382,12 @@ void profiler_suspend_and_sample_thread(int aThreadId, uint32_t aFeatures,
 
       // Suspend, sample, and then resume the target thread.
       Sampler sampler(lock);
+      TimeStamp now = TimeStamp::NowUnfuzzed();
       sampler.SuspendAndSampleAndResumeThread(
-          lock, registeredThread, [&](const Registers& aRegs) {
-            // The target thread is now suspended. Collect a native backtrace,
-            // and call the callback.
+          lock, registeredThread, now,
+          [&](const Registers& aRegs, const TimeStamp& aNow) {
+            // The target thread is now suspended. Collect a native
+            // backtrace, and call the callback.
             bool isSynchronous = false;
 #  if defined(HAVE_FASTINIT_NATIVE_UNWIND)
             if (aSampleNative) {
@@ -3269,7 +3398,8 @@ void profiler_suspend_and_sample_thread(int aThreadId, uint32_t aFeatures,
               DoFramePointerBacktrace(lock, registeredThread, aRegs,
                                       nativeStack);
 #    elif defined(USE_MOZ_STACK_WALK)
-          DoMozStackWalkBacktrace(lock, registeredThread, aRegs, nativeStack);
+              DoMozStackWalkBacktrace(lock, registeredThread, aRegs,
+                                      nativeStack);
 #    else
 #      error "Invalid configuration"
 #    endif
diff --git a/mozglue/baseprofiler/core/platform.h b/mozglue/baseprofiler/core/platform.h
index ea62f63be6..83cf45febc 100644
--- a/mozglue/baseprofiler/core/platform.h
+++ b/mozglue/baseprofiler/core/platform.h
@@ -34,7 +34,6 @@
 #include "BaseProfiler.h"
 
 #include "mozilla/Logging.h"
-#include "mozilla/PlatformMutex.h"
 #include "mozilla/UniquePtr.h"
 #include "mozilla/Vector.h"
 
@@ -83,16 +82,6 @@ class JSONWriter;
 
 namespace baseprofiler {
 
-// Thin shell around mozglue PlatformMutex, for Base Profiler internal use.
-// Does not preserve behavior in JS record/replay.
-class PSMutex : private mozilla::detail::MutexImpl {
- public:
-  PSMutex()
-      : mozilla::detail::MutexImpl() {}
-  void Lock() { mozilla::detail::MutexImpl::lock(); }
-  void Unlock() { mozilla::detail::MutexImpl::unlock(); }
-};
-
 typedef uint8_t* Address;
 
 class PlatformData;
@@ -118,9 +107,8 @@ void profiler_get_profile_json_into_lazily_allocated_buffer(
 // Flags to conveniently track various JS instrumentations.
 enum class JSInstrumentationFlags {
   StackSampling = 0x1,
-  TrackOptimizations = 0x2,
-  TraceLogging = 0x4,
-  Allocations = 0x8
+  TraceLogging = 0x2,
+  Allocations = 0x4,
 };
 
 // Record an exit profile from a child process.
diff --git a/mozglue/baseprofiler/core/shared-libraries-macos.cc b/mozglue/baseprofiler/core/shared-libraries-macos.cc
index 52d5f5f154..f6a9bccb33 100644
--- a/mozglue/baseprofiler/core/shared-libraries-macos.cc
+++ b/mozglue/baseprofiler/core/shared-libraries-macos.cc
@@ -58,10 +58,11 @@ class MOZ_RAII SharedLibrariesLock {
   void operator=(const SharedLibrariesLock&) = delete;
 
  private:
-  static mozilla::baseprofiler::PSMutex sSharedLibrariesMutex;
+  static mozilla::baseprofiler::detail::BaseProfilerMutex sSharedLibrariesMutex;
 };
 
-mozilla::baseprofiler::PSMutex SharedLibrariesLock::sSharedLibrariesMutex;
+mozilla::baseprofiler::detail::BaseProfilerMutex
+    SharedLibrariesLock::sSharedLibrariesMutex;
 
 static void SharedLibraryAddImage(const struct mach_header* mh,
                                   intptr_t vmaddr_slide) {
diff --git a/mozglue/baseprofiler/moz.build b/mozglue/baseprofiler/moz.build
index c539779c2b..e27a98e28e 100644
--- a/mozglue/baseprofiler/moz.build
+++ b/mozglue/baseprofiler/moz.build
@@ -81,6 +81,11 @@ EXPORTS += [
 
 EXPORTS.mozilla += [
     'public/BaseProfilerCounts.h',
+    'public/BaseProfilerDetail.h',
+    'public/BlocksRingBuffer.h',
+    'public/leb128iterator.h',
+    'public/ModuloBuffer.h',
+    'public/PowerOfTwo.h',
 ]
 
 if CONFIG['MOZ_VTUNE']:
diff --git a/mozglue/baseprofiler/public/BaseProfiler.h b/mozglue/baseprofiler/public/BaseProfiler.h
index 1542f121a9..f70f7328ba 100644
--- a/mozglue/baseprofiler/public/BaseProfiler.h
+++ b/mozglue/baseprofiler/public/BaseProfiler.h
@@ -61,6 +61,8 @@
                                                 categoryPair, ctx, flags)
 
 #  define BASE_PROFILER_ADD_MARKER(markerName, categoryPair)
+#  define BASE_PROFILER_ADD_MARKER_WITH_PAYLOAD( \
+      markerName, categoryPair, PayloadType, parenthesizedPayloadArgs)
 
 #  define MOZDECLARE_DOCSHELL_AND_HISTORY_ID(docShell)
 #  define BASE_PROFILER_TRACING(categoryString, markerName, categoryPair, kind)
@@ -76,6 +78,8 @@
 #  define AUTO_BASE_PROFILER_TEXT_MARKER_DOCSHELL_CAUSE( \
       markerName, text, categoryPair, docShell, cause)
 
+#  define AUTO_PROFILER_STATS(name)
+
 #else  // !MOZ_BASE_PROFILER
 
 #  include "BaseProfilingStack.h"
@@ -85,6 +89,7 @@
 #  include "mozilla/Attributes.h"
 #  include "mozilla/GuardObjects.h"
 #  include "mozilla/Maybe.h"
+#  include "mozilla/PowerOfTwo.h"
 #  include "mozilla/Sprintf.h"
 #  include "mozilla/ThreadLocal.h"
 #  include "mozilla/TimeStamp.h"
@@ -120,44 +125,40 @@ class SpliceableJSONWriter;
 // values are used internally only and so can be changed without consequence.
 // Any changes to this list should also be applied to the feature list in
 // toolkit/components/extensions/schemas/geckoProfiler.json.
-#  define BASE_PROFILER_FOR_EACH_FEATURE(MACRO)                               \
-    MACRO(0, "java", Java, "Profile Java code, Android only")                 \
-                                                                              \
-    MACRO(1, "js", JS,                                                        \
-          "Get the JS engine to expose the JS stack to the profiler")         \
-                                                                              \
-    /* The DevTools profiler doesn't want the native addresses. */            \
-    MACRO(2, "leaf", Leaf, "Include the C++ leaf node if not stackwalking")   \
-                                                                              \
-    MACRO(3, "mainthreadio", MainThreadIO,                                    \
-          "Add main thread I/O to the profile")                               \
-                                                                              \
-    MACRO(4, "memory", Memory, "Add memory measurements")                     \
-                                                                              \
-    MACRO(5, "privacy", Privacy,                                              \
-          "Do not include user-identifiable information")                     \
-                                                                              \
-    MACRO(6, "responsiveness", Responsiveness,                                \
-          "Collect thread responsiveness information")                        \
-                                                                              \
-    MACRO(7, "screenshots", Screenshots,                                      \
-          "Take a snapshot of the window on every composition")               \
-                                                                              \
-    MACRO(8, "seqstyle", SequentialStyle,                                     \
-          "Disable parallel traversal in styling")                            \
-                                                                              \
-    MACRO(9, "stackwalk", StackWalk,                                          \
-          "Walk the C++ stack, not available on all platforms")               \
-                                                                              \
-    MACRO(10, "tasktracer", TaskTracer,                                       \
-          "Start profiling with feature TaskTracer")                          \
-                                                                              \
-    MACRO(11, "threads", Threads, "Profile the registered secondary threads") \
-                                                                              \
-    MACRO(12, "trackopts", TrackOptimizations,                                \
-          "Have the JavaScript engine track JIT optimizations")               \
-                                                                              \
-    MACRO(13, "jstracer", JSTracer, "Enable tracing of the JavaScript engine")
+#  define BASE_PROFILER_FOR_EACH_FEATURE(MACRO)                                \
+    MACRO(0, "java", Java, "Profile Java code, Android only")                  \
+                                                                               \
+    MACRO(1, "js", JS,                                                         \
+          "Get the JS engine to expose the JS stack to the profiler")          \
+                                                                               \
+    /* The DevTools profiler doesn't want the native addresses. */             \
+    MACRO(2, "leaf", Leaf, "Include the C++ leaf node if not stackwalking")    \
+                                                                               \
+    MACRO(3, "mainthreadio", MainThreadIO,                                     \
+          "Add main thread I/O to the profile")                                \
+                                                                               \
+    MACRO(4, "privacy", Privacy,                                               \
+          "Do not include user-identifiable information")                      \
+                                                                               \
+    MACRO(5, "screenshots", Screenshots,                                       \
+          "Take a snapshot of the window on every composition")                \
+                                                                               \
+    MACRO(6, "seqstyle", SequentialStyle,                                      \
+          "Disable parallel traversal in styling")                             \
+                                                                               \
+    MACRO(7, "stackwalk", StackWalk,                                           \
+          "Walk the C++ stack, not available on all platforms")                \
+                                                                               \
+    MACRO(8, "tasktracer", TaskTracer,                                         \
+          "Start profiling with feature TaskTracer")                           \
+                                                                               \
+    MACRO(9, "threads", Threads, "Profile the registered secondary threads")   \
+                                                                               \
+    MACRO(10, "jstracer", JSTracer, "Enable tracing of the JavaScript engine") \
+                                                                               \
+    MACRO(14, "nostacksampling", NoStackSampling,                              \
+          "Disable all stack sampling: Cancels \"js\", \"leaf\", "             \
+          "\"stackwalk\" and labels")
 
 struct ProfilerFeature {
 #  define DECLARE(n_, str_, Name_, desc_)                     \
@@ -194,18 +195,25 @@ class RacyFeatures {
 
   MFBT_API static void SetInactive();
 
+  MFBT_API static void SetPaused();
+
+  MFBT_API static void SetUnpaused();
+
   MFBT_API static bool IsActive();
 
   MFBT_API static bool IsActiveWithFeature(uint32_t aFeature);
 
   MFBT_API static bool IsActiveWithoutPrivacy();
 
- private:
-  static const uint32_t Active = 1u << 31;
+  MFBT_API static bool IsActiveAndUnpausedWithoutPrivacy();
 
-// Ensure Active doesn't overlap with any of the feature bits.
+ private:
+  static constexpr uint32_t Active = 1u << 31;
+  static constexpr uint32_t Paused = 1u << 30;
+
+// Ensure Active/Paused don't overlap with any of the feature bits.
 #  define NO_OVERLAP(n_, str_, Name_, desc_) \
-    static_assert(ProfilerFeature::Name_ != Active, "bad Active value");
+    static_assert(ProfilerFeature::Name_ != Paused, "bad feature value");
 
   BASE_PROFILER_FOR_EACH_FEATURE(NO_OVERLAP);
 
@@ -225,20 +233,20 @@ MFBT_API bool IsThreadBeingProfiled();
 // Start and stop the profiler
 //---------------------------------------------------------------------------
 
-static constexpr uint32_t BASE_PROFILER_DEFAULT_ENTRIES =
+static constexpr PowerOfTwo32 BASE_PROFILER_DEFAULT_ENTRIES =
 #  if !defined(ARCH_ARMV6)
-    1u << 20;  // 1'048'576
+    MakePowerOfTwo32<1u << 20>();  // 1'048'576 entries = 8MB
 #  else
-    1u << 17;  // 131'072
+    MakePowerOfTwo32<1u << 17>();  // 131'072 entries = 1MB
 #  endif
 
 // Startup profiling usually need to capture more data, especially on slow
 // systems.
-static constexpr uint32_t BASE_PROFILER_DEFAULT_STARTUP_ENTRIES =
+static constexpr PowerOfTwo32 BASE_PROFILER_DEFAULT_STARTUP_ENTRIES =
 #  if !defined(ARCH_ARMV6)
-    1u << 22;  // 4'194'304
+    MakePowerOfTwo32<1u << 22>();  // 4'194'304 entries = 32MB
 #  else
-    1u << 17;  // 131'072
+    MakePowerOfTwo32<1u << 17>();  // 131'072 = 1MB
 #  endif
 
 #  define BASE_PROFILER_DEFAULT_DURATION 20
@@ -262,8 +270,8 @@ MFBT_API void profiler_shutdown();
 // selected options. Stops and restarts the profiler if it is already active.
 // After starting the profiler is "active". The samples will be recorded in a
 // circular buffer.
-//   "aCapacity" is the maximum number of entries in the profiler's circular
-//               buffer.
+//   "aCapacity" is the maximum number of 8-byte entries in the profiler's
+//               circular buffer.
 //   "aInterval" the sampling interval, measured in millseconds.
 //   "aFeatures" is the feature set. Features unsupported by this
 //               platform/configuration are ignored.
@@ -274,7 +282,7 @@ MFBT_API void profiler_shutdown();
 //              (b) the filter is of the form "pid:<n>" where n is the process
 //                  id of the process that the thread is running in.
 //   "aDuration" is the duration of entries in the profiler's circular buffer.
-MFBT_API void profiler_start(uint32_t aCapacity, double aInterval,
+MFBT_API void profiler_start(PowerOfTwo32 aCapacity, double aInterval,
                              uint32_t aFeatures, const char** aFilters,
                              uint32_t aFilterCount,
                              const Maybe<double>& aDuration = Nothing());
@@ -289,7 +297,7 @@ MFBT_API void profiler_stop();
 // The only difference to profiler_start is that the current buffer contents are
 // not discarded if the profiler is already running with the requested settings.
 MFBT_API void profiler_ensure_started(
-    uint32_t aCapacity, double aInterval, uint32_t aFeatures,
+    PowerOfTwo32 aCapacity, double aInterval, uint32_t aFeatures,
     const char** aFilters, uint32_t aFilterCount,
     const Maybe<double>& aDuration = Nothing());
 
@@ -394,6 +402,19 @@ inline bool profiler_is_active() {
   return baseprofiler::detail::RacyFeatures::IsActive();
 }
 
+// Same as profiler_is_active(), but with the same extra checks that determine
+// if the profiler would currently store markers. So this should be used before
+// doing some potentially-expensive work that's used in a marker. E.g.:
+//
+//   if (profiler_can_accept_markers()) {
+//     ExpensiveMarkerPayload expensivePayload = CreateExpensivePayload();
+//     BASE_PROFILER_ADD_MARKER_WITH_PAYLOAD(name, OTHER, expensivePayload);
+//   }
+inline bool profiler_can_accept_markers() {
+  return baseprofiler::detail::RacyFeatures::
+      IsActiveAndUnpausedWithoutPrivacy();
+}
+
 // Is the profiler active, and is the current thread being profiled?
 // (Same caveats and recommented usage as profiler_is_active().)
 inline bool profiler_thread_is_being_profiled() {
@@ -479,10 +500,42 @@ using UniqueProfilerBacktrace =
 // if the profiler is inactive or in privacy mode.
 MFBT_API UniqueProfilerBacktrace profiler_get_backtrace();
 
+struct ProfilerStats {
+  unsigned n = 0;
+  double sum = 0;
+  double min = std::numeric_limits<double>::max();
+  double max = 0;
+  void Count(double v) {
+    ++n;
+    sum += v;
+    if (v < min) {
+      min = v;
+    }
+    if (v > max) {
+      max = v;
+    }
+  }
+};
+
 struct ProfilerBufferInfo {
+  // Index of the oldest entry.
   uint64_t mRangeStart;
+  // Index of the newest entry.
   uint64_t mRangeEnd;
+  // Buffer capacity in number of 8-byte entries.
   uint32_t mEntryCount;
+  // Sampling stats: Interval (ns) between successive samplings.
+  ProfilerStats mIntervalsNs;
+  // Sampling stats: Total duration (ns) of each sampling. (Split detail below.)
+  ProfilerStats mOverheadsNs;
+  // Sampling stats: Time (ns) to acquire the lock before sampling.
+  ProfilerStats mLockingsNs;
+  // Sampling stats: Time (ns) to discard expired data.
+  ProfilerStats mCleaningsNs;
+  // Sampling stats: Time (ns) to collect counter data.
+  ProfilerStats mCountersNs;
+  // Sampling stats: Time (ns) to sample thread stacks.
+  ProfilerStats mThreadsNs;
 };
 
 // Get information about the current buffer status.
@@ -493,6 +546,62 @@ struct ProfilerBufferInfo {
 // buffer is being written to, and how much data is visible.
 MFBT_API Maybe<ProfilerBufferInfo> profiler_get_buffer_info();
 
+// Uncomment the following line to display profiler runtime statistics at
+// shutdown.
+// #  define PROFILER_RUNTIME_STATS
+
+#  ifdef PROFILER_RUNTIME_STATS
+struct StaticBaseProfilerStats {
+  explicit StaticBaseProfilerStats(const char* aName) : mName(aName) {}
+  ~StaticBaseProfilerStats() {
+    long long n = static_cast<long long>(mNumberDurations);
+    if (n != 0) {
+      long long sumNs = static_cast<long long>(mSumDurationsNs);
+      printf("Profiler stats `%s`: %lld ns / %lld = %lld ns\n", mName, sumNs, n,
+             sumNs / n);
+    } else {
+      printf("Profiler stats `%s`: (nothing)\n", mName);
+    }
+  }
+  Atomic<long long> mSumDurationsNs{0};
+  Atomic<long long> mNumberDurations{0};
+
+ private:
+  const char* mName;
+};
+
+class MOZ_RAII AutoProfilerStats {
+ public:
+  explicit AutoProfilerStats(
+      StaticBaseProfilerStats& aStats MOZ_GUARD_OBJECT_NOTIFIER_PARAM)
+      : mStats(aStats), mStart(TimeStamp::NowUnfuzzed()) {
+    MOZ_GUARD_OBJECT_NOTIFIER_INIT;
+  }
+
+  ~AutoProfilerStats() {
+    mStats.mSumDurationsNs += int64_t(
+        (TimeStamp::NowUnfuzzed() - mStart).ToMicroseconds() * 1000 + 0.5);
+    ++mStats.mNumberDurations;
+  }
+
+ private:
+  MOZ_DECL_USE_GUARD_OBJECT_NOTIFIER
+
+  StaticBaseProfilerStats& mStats;
+  TimeStamp mStart;
+};
+
+#    define AUTO_PROFILER_STATS(name)                                      \
+      static ::mozilla::baseprofiler::StaticBaseProfilerStats sStat##name( \
+          #name);                                                          \
+      ::mozilla::baseprofiler::AutoProfilerStats autoStat##name(sStat##name);
+
+#  else  // PROFILER_RUNTIME_STATS
+
+#    define AUTO_PROFILER_STATS(name)
+
+#  endif  // PROFILER_RUNTIME_STATS else
+
 //---------------------------------------------------------------------------
 // Put profiling data into the profiler (labels and markers)
 //---------------------------------------------------------------------------
@@ -593,16 +702,35 @@ MFBT_API Maybe<ProfilerBufferInfo> profiler_get_buffer_info();
 // certain length of time. A no-op if the profiler is inactive or in privacy
 // mode.
 
-#  define BASE_PROFILER_ADD_MARKER(markerName, categoryPair) \
-    ::mozilla::baseprofiler::profiler_add_marker(            \
-        markerName,                                          \
-        ::mozilla::baseprofiler::ProfilingCategoryPair::categoryPair)
+#  define BASE_PROFILER_ADD_MARKER(markerName, categoryPair)             \
+    do {                                                                 \
+      AUTO_PROFILER_STATS(base_add_marker);                              \
+      ::mozilla::baseprofiler::profiler_add_marker(                      \
+          markerName,                                                    \
+          ::mozilla::baseprofiler::ProfilingCategoryPair::categoryPair); \
+    } while (false)
 
 MFBT_API void profiler_add_marker(const char* aMarkerName,
                                   ProfilingCategoryPair aCategoryPair);
+
+// `PayloadType` is a sub-class of BaseMarkerPayload, `parenthesizedPayloadArgs`
+// is the argument list used to construct that `PayloadType`. E.g.:
+// `BASE_PROFILER_ADD_MARKER_WITH_PAYLOAD("Load", DOM, TextMarkerPayload,
+//                                        ("text", start, end, ds, dsh))`
+#  define BASE_PROFILER_ADD_MARKER_WITH_PAYLOAD(                        \
+      markerName, categoryPair, PayloadType, parenthesizedPayloadArgs)  \
+    do {                                                                \
+      AUTO_PROFILER_STATS(base_add_marker_with_##PayloadType);          \
+      ::mozilla::baseprofiler::profiler_add_marker(                     \
+          markerName,                                                   \
+          ::mozilla::baseprofiler::ProfilingCategoryPair::categoryPair, \
+          PayloadType parenthesizedPayloadArgs);                        \
+    } while (false)
+
 MFBT_API void profiler_add_marker(const char* aMarkerName,
                                   ProfilingCategoryPair aCategoryPair,
-                                  UniquePtr<ProfilerMarkerPayload> aPayload);
+                                  const ProfilerMarkerPayload& aPayload);
+
 MFBT_API void profiler_add_js_marker(const char* aMarkerName);
 
 // Insert a marker in the profile timeline for a specified thread.
@@ -701,7 +829,7 @@ class MOZ_RAII AutoProfilerTextMarker {
       : mMarkerName(aMarkerName),
         mText(aText),
         mCategoryPair(aCategoryPair),
-        mStartTime(TimeStamp::Now()),
+        mStartTime(TimeStamp::NowUnfuzzed()),
         mCause(std::move(aCause)),
         mDocShellId(aDocShellId),
         mDocShellHistoryId(aDocShellHistoryId) {
@@ -710,8 +838,8 @@ class MOZ_RAII AutoProfilerTextMarker {
 
   ~AutoProfilerTextMarker() {
     profiler_add_text_marker(mMarkerName, mText, mCategoryPair, mStartTime,
-                             TimeStamp::Now(), mDocShellId, mDocShellHistoryId,
-                             std::move(mCause));
+                             TimeStamp::NowUnfuzzed(), mDocShellId,
+                             mDocShellHistoryId, std::move(mCause));
   }
 
  protected:
diff --git a/mozglue/baseprofiler/public/BaseProfilerDetail.h b/mozglue/baseprofiler/public/BaseProfilerDetail.h
new file mode 100644
index 0000000000..ef57449f1c
--- /dev/null
+++ b/mozglue/baseprofiler/public/BaseProfilerDetail.h
@@ -0,0 +1,166 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// Internal Base Profiler utilities.
+
+#ifndef BaseProfilerDetail_h
+#define BaseProfilerDetail_h
+
+#include "mozilla/Maybe.h"
+#include "mozilla/PlatformMutex.h"
+
+#ifdef DEBUG
+#  include "BaseProfiler.h"
+#  ifdef MOZ_BASE_PROFILER
+#    include "mozilla/Atomics.h"
+// When #defined, safety-checking code is added. By default: DEBUG builds,
+// and we need `MOZ_BASE_PROFILER` to use `profiler_current_thread_id()`.
+#    define MOZ_BASE_PROFILER_DEBUG
+#  endif  // MOZ_BASE_PROFILER
+#endif    // DEBUG
+
+namespace mozilla {
+namespace baseprofiler {
+namespace detail {
+
+// Thin shell around mozglue PlatformMutex, for Base Profiler internal use.
+class BaseProfilerMutex : private ::mozilla::detail::MutexImpl {
+ public:
+  BaseProfilerMutex()
+      : ::mozilla::detail::MutexImpl() {}
+
+  BaseProfilerMutex(const BaseProfilerMutex&) = delete;
+  BaseProfilerMutex& operator=(const BaseProfilerMutex&) = delete;
+  BaseProfilerMutex(BaseProfilerMutex&&) = delete;
+  BaseProfilerMutex& operator=(BaseProfilerMutex&&) = delete;
+
+#ifdef MOZ_BASE_PROFILER_DEBUG
+  ~BaseProfilerMutex() { MOZ_ASSERT(mOwningThreadId == 0); }
+#endif  // MOZ_BASE_PROFILER_DEBUG
+
+  void Lock() {
+#ifdef MOZ_BASE_PROFILER_DEBUG
+    // This is only designed to catch recursive locking.
+    const int tid = baseprofiler::profiler_current_thread_id();
+    MOZ_ASSERT(tid != 0);
+    MOZ_ASSERT(mOwningThreadId != tid);
+#endif  // MOZ_BASE_PROFILER_DEBUG
+    ::mozilla::detail::MutexImpl::lock();
+#ifdef MOZ_BASE_PROFILER_DEBUG
+    MOZ_ASSERT(mOwningThreadId == 0);
+    mOwningThreadId = tid;
+#endif  // MOZ_BASE_PROFILER_DEBUG
+  }
+
+  void Unlock() {
+#ifdef MOZ_BASE_PROFILER_DEBUG
+    // This should never trigger! But check just in case something has gone
+    // very wrong.
+    MOZ_ASSERT(mOwningThreadId == baseprofiler::profiler_current_thread_id());
+    // We're still holding the mutex here, so it's safe to just reset
+    // `mOwningThreadId`.
+    mOwningThreadId = 0;
+#endif  // MOZ_BASE_PROFILER_DEBUG
+    ::mozilla::detail::MutexImpl::unlock();
+  }
+
+  void AssertCurrentThreadOwns() const {
+#ifdef MOZ_BASE_PROFILER_DEBUG
+    MOZ_ASSERT(mOwningThreadId == baseprofiler::profiler_current_thread_id());
+#endif  // MOZ_BASE_PROFILER_DEBUG
+  }
+
+#ifdef MOZ_BASE_PROFILER_DEBUG
+ private:
+  Atomic<int, MemoryOrdering::SequentiallyConsistent>
+      mOwningThreadId{0};
+#endif  // MOZ_BASE_PROFILER_DEBUG
+};
+
+// RAII class to lock a mutex.
+class MOZ_RAII BaseProfilerAutoLock {
+ public:
+  explicit BaseProfilerAutoLock(BaseProfilerMutex& aMutex) : mMutex(aMutex) {
+    mMutex.Lock();
+  }
+
+  BaseProfilerAutoLock(const BaseProfilerAutoLock&) = delete;
+  BaseProfilerAutoLock& operator=(const BaseProfilerAutoLock&) = delete;
+  BaseProfilerAutoLock(BaseProfilerAutoLock&&) = delete;
+  BaseProfilerAutoLock& operator=(BaseProfilerAutoLock&&) = delete;
+
+  ~BaseProfilerAutoLock() { mMutex.Unlock(); }
+
+ private:
+  BaseProfilerMutex& mMutex;
+};
+
+// Thin shell around mozglue PlatformMutex, for Base Profiler internal use.
+// Actual mutex may be disabled at construction time.
+class BaseProfilerMaybeMutex : private ::mozilla::detail::MutexImpl {
+ public:
+  explicit BaseProfilerMaybeMutex(bool aActivate) {
+    if (aActivate) {
+      mMaybeMutex.emplace();
+    }
+  }
+
+  BaseProfilerMaybeMutex(const BaseProfilerMaybeMutex&) = delete;
+  BaseProfilerMaybeMutex& operator=(const BaseProfilerMaybeMutex&) = delete;
+  BaseProfilerMaybeMutex(BaseProfilerMaybeMutex&&) = delete;
+  BaseProfilerMaybeMutex& operator=(BaseProfilerMaybeMutex&&) = delete;
+
+  ~BaseProfilerMaybeMutex() = default;
+
+  bool IsActivated() const { return mMaybeMutex.isSome(); }
+
+  void Lock() {
+    if (IsActivated()) {
+      mMaybeMutex->Lock();
+    }
+  }
+
+  void Unlock() {
+    if (IsActivated()) {
+      mMaybeMutex->Unlock();
+    }
+  }
+
+  void AssertCurrentThreadOwns() const {
+#ifdef MOZ_BASE_PROFILER_DEBUG
+    if (IsActivated()) {
+      mMaybeMutex->AssertCurrentThreadOwns();
+    }
+#endif  // MOZ_BASE_PROFILER_DEBUG
+  }
+
+ private:
+  Maybe<BaseProfilerMutex> mMaybeMutex;
+};
+
+// RAII class to lock a mutex.
+class MOZ_RAII BaseProfilerMaybeAutoLock {
+ public:
+  explicit BaseProfilerMaybeAutoLock(BaseProfilerMaybeMutex& aMaybeMutex)
+      : mMaybeMutex(aMaybeMutex) {
+    mMaybeMutex.Lock();
+  }
+
+  BaseProfilerMaybeAutoLock(const BaseProfilerMaybeAutoLock&) = delete;
+  BaseProfilerMaybeAutoLock& operator=(const BaseProfilerMaybeAutoLock&) =
+      delete;
+  BaseProfilerMaybeAutoLock(BaseProfilerMaybeAutoLock&&) = delete;
+  BaseProfilerMaybeAutoLock& operator=(BaseProfilerMaybeAutoLock&&) = delete;
+
+  ~BaseProfilerMaybeAutoLock() { mMaybeMutex.Unlock(); }
+
+ private:
+  BaseProfilerMaybeMutex& mMaybeMutex;
+};
+
+}  // namespace detail
+}  // namespace baseprofiler
+}  // namespace mozilla
+
+#endif  // BaseProfilerDetail_h
diff --git a/mozglue/baseprofiler/public/BaseProfilerMarkerPayload.h b/mozglue/baseprofiler/public/BaseProfilerMarkerPayload.h
index 93b9c312d2..7973a71880 100644
--- a/mozglue/baseprofiler/public/BaseProfilerMarkerPayload.h
+++ b/mozglue/baseprofiler/public/BaseProfilerMarkerPayload.h
@@ -11,7 +11,9 @@
 #  error Do not #include this header when MOZ_BASE_PROFILER is not #defined.
 #endif
 
+#include "mozilla/Atomics.h"
 #include "mozilla/Attributes.h"
+#include "mozilla/BlocksRingBuffer.h"
 #include "mozilla/Maybe.h"
 #include "mozilla/RefPtr.h"
 #include "mozilla/TimeStamp.h"
@@ -35,99 +37,184 @@ class ProfilerMarkerPayload {
       const Maybe<std::string>& aDocShellId = Nothing(),
       const Maybe<uint32_t>& aDocShellHistoryId = Nothing(),
       UniqueProfilerBacktrace aStack = nullptr)
-      : mStack(std::move(aStack)),
-        mDocShellId(aDocShellId),
-        mDocShellHistoryId(aDocShellHistoryId) {}
+      : mCommonProps{TimeStamp{}, TimeStamp{}, std::move(aStack),
+                     std::move(aDocShellId), std::move(aDocShellHistoryId)} {}
 
   ProfilerMarkerPayload(const TimeStamp& aStartTime, const TimeStamp& aEndTime,
                         const Maybe<std::string>& aDocShellId = Nothing(),
                         const Maybe<uint32_t>& aDocShellHistoryId = Nothing(),
                         UniqueProfilerBacktrace aStack = nullptr)
-      : mStartTime(aStartTime),
-        mEndTime(aEndTime),
-        mStack(std::move(aStack)),
-        mDocShellId(aDocShellId),
-        mDocShellHistoryId(aDocShellHistoryId) {}
+      : mCommonProps{aStartTime, aEndTime, std::move(aStack),
+                     std::move(aDocShellId), std::move(aDocShellHistoryId)} {}
 
   virtual ~ProfilerMarkerPayload() {}
 
+  // Compute the number of bytes needed to serialize the `DeserializerTag` and
+  // payload, including in the no-payload (nullptr) case.
+  static BlocksRingBuffer::Length TagAndSerializationBytes(
+      const ProfilerMarkerPayload* aPayload) {
+    if (!aPayload) {
+      return sizeof(DeserializerTag);
+    }
+    return aPayload->TagAndSerializationBytes();
+  }
+
+  // Serialize the payload into an EntryWriter, including in the no-payload
+  // (nullptr) case. Must be of the exact size given by
+  // `TagAndSerializationBytes(aPayload)`.
+  static void TagAndSerialize(const ProfilerMarkerPayload* aPayload,
+                              BlocksRingBuffer::EntryWriter& aEntryWriter) {
+    if (!aPayload) {
+      aEntryWriter.WriteObject(DeserializerTag(0));
+      return;
+    }
+    aPayload->SerializeTagAndPayload(aEntryWriter);
+  }
+
+  // Deserialize a payload from an EntryReader, including in the no-payload
+  // (nullptr) case.
+  static UniquePtr<ProfilerMarkerPayload> DeserializeTagAndPayload(
+      mozilla::BlocksRingBuffer::EntryReader& aER) {
+    const auto tag = aER.ReadObject<DeserializerTag>();
+    Deserializer deserializer = DeserializerForTag(tag);
+    return deserializer(aER);
+  }
+
   virtual void StreamPayload(SpliceableJSONWriter& aWriter,
                              const TimeStamp& aProcessStartTime,
-                             UniqueStacks& aUniqueStacks) = 0;
+                             UniqueStacks& aUniqueStacks) const = 0;
 
-  TimeStamp GetStartTime() const { return mStartTime; }
+  TimeStamp GetStartTime() const { return mCommonProps.mStartTime; }
 
  protected:
+  // A `Deserializer` is a free function that can read a serialized payload from
+  // an `EntryReader` and return a reconstructed `ProfilerMarkerPayload`
+  // sub-object (may be null if there was no payload).
+  typedef UniquePtr<ProfilerMarkerPayload> (*Deserializer)(
+      BlocksRingBuffer::EntryReader&);
+
+  // A `DeserializerTag` will be added before the payload, to help select the
+  // correct deserializer when reading back the payload.
+  using DeserializerTag = unsigned char;
+
+  // This needs to be big enough to handle all possible sub-types of
+  // ProfilerMarkerPayload.
+  static constexpr DeserializerTag DeserializerMax = 32;
+
+  // We need an atomic type that can hold a `DeserializerTag`. (Atomic doesn't
+  // work with too-small types.)
+  using DeserializerTagAtomic = int;
+
+  // Number of currently-registered deserializers.
+  static Atomic<DeserializerTagAtomic, ReleaseAcquire,
+                recordreplay::Behavior::DontPreserve>
+      sDeserializerCount;
+
+  // List of currently-registered deserializers.
+  // sDeserializers[0] is a no-payload deserializer.
+  static Deserializer sDeserializers[DeserializerMax];
+
+  // Get the `DeserializerTag` for a `Deserializer` (which gets registered on
+  // the first call.) Tag 0 means no payload; a null `aDeserializer` gives that
+  // 0 tag.
+  MFBT_API static DeserializerTag TagForDeserializer(
+      Deserializer aDeserializer);
+
+  // Get the `Deserializer` for a given `DeserializerTag`.
+  // Tag 0 is reserved as no-payload deserializer (which returns nullptr).
+  MFBT_API static Deserializer DeserializerForTag(DeserializerTag aTag);
+
+  struct CommonProps {
+    TimeStamp mStartTime;
+    TimeStamp mEndTime;
+    UniqueProfilerBacktrace mStack;
+    Maybe<std::string> mDocShellId;
+    Maybe<uint32_t> mDocShellHistoryId;
+  };
+
+  // Deserializers can use this base constructor.
+  explicit ProfilerMarkerPayload(CommonProps&& aCommonProps)
+      : mCommonProps(std::move(aCommonProps)) {}
+
+  // Serialization/deserialization of common props in ProfilerMarkerPayload.
+  MFBT_API BlocksRingBuffer::Length CommonPropsTagAndSerializationBytes() const;
+  MFBT_API void SerializeTagAndCommonProps(
+      DeserializerTag aDeserializerTag,
+      BlocksRingBuffer::EntryWriter& aEntryWriter) const;
+  MFBT_API static CommonProps DeserializeCommonProps(
+      BlocksRingBuffer::EntryReader& aEntryReader);
+
   MFBT_API void StreamType(const char* aMarkerType,
-                           SpliceableJSONWriter& aWriter);
+                           SpliceableJSONWriter& aWriter) const;
+
   MFBT_API void StreamCommonProps(const char* aMarkerType,
                                   SpliceableJSONWriter& aWriter,
                                   const TimeStamp& aProcessStartTime,
-                                  UniqueStacks& aUniqueStacks);
-
-  void SetStack(UniqueProfilerBacktrace aStack) { mStack = std::move(aStack); }
-
-  void SetDocShellHistoryId(const Maybe<uint32_t>& aDocShellHistoryId) {
-    mDocShellHistoryId = aDocShellHistoryId;
-  }
-
-  void SetDocShellId(const Maybe<std::string>& aDocShellId) {
-    mDocShellId = aDocShellId;
-  }
+                                  UniqueStacks& aUniqueStacks) const;
 
  private:
-  TimeStamp mStartTime;
-  TimeStamp mEndTime;
-  UniqueProfilerBacktrace mStack;
-  Maybe<std::string> mDocShellId;
-  Maybe<uint32_t> mDocShellHistoryId;
+  // Compute the number of bytes needed to serialize the `DeserializerTag` and
+  // payload in `SerializeTagAndPayload` below.
+  virtual BlocksRingBuffer::Length TagAndSerializationBytes() const = 0;
+
+  // Serialize the `DeserializerTag` and payload into an EntryWriter.
+  // Must be of the exact size given by `TagAndSerializationBytes()`.
+  virtual void SerializeTagAndPayload(
+      BlocksRingBuffer::EntryWriter& aEntryWriter) const = 0;
+
+  CommonProps mCommonProps;
 };
 
-#define DECL_BASE_STREAM_PAYLOAD                              \
-  virtual void StreamPayload(                                 \
-      ::mozilla::baseprofiler::SpliceableJSONWriter& aWriter, \
-      const ::mozilla::TimeStamp& aProcessStartTime,          \
-      ::mozilla::baseprofiler::UniqueStacks& aUniqueStacks) override;
+#define DECL_BASE_STREAM_PAYLOAD                                               \
+  MFBT_API void StreamPayload(                                                 \
+      ::mozilla::baseprofiler::SpliceableJSONWriter& aWriter,                  \
+      const ::mozilla::TimeStamp& aProcessStartTime,                           \
+      ::mozilla::baseprofiler::UniqueStacks& aUniqueStacks) const override;    \
+  static UniquePtr<ProfilerMarkerPayload> Deserialize(                         \
+      BlocksRingBuffer::EntryReader& aEntryReader);                            \
+  MFBT_API BlocksRingBuffer::Length TagAndSerializationBytes() const override; \
+  MFBT_API void SerializeTagAndPayload(                                        \
+      BlocksRingBuffer::EntryWriter& aEntryWriter) const override;
 
 // TODO: Increase the coverage of tracing markers that include DocShell
 // information
 class TracingMarkerPayload : public ProfilerMarkerPayload {
  public:
-  TracingMarkerPayload(const char* aCategory, TracingKind aKind,
-                       const Maybe<std::string>& aDocShellId = Nothing(),
-                       const Maybe<uint32_t>& aDocShellHistoryId = Nothing(),
-                       UniqueProfilerBacktrace aCause = nullptr)
-      : mCategory(aCategory), mKind(aKind) {
-    if (aCause) {
-      SetStack(std::move(aCause));
-    }
-    SetDocShellId(aDocShellId);
-    SetDocShellHistoryId(aDocShellHistoryId);
-  }
+  MFBT_API TracingMarkerPayload(
+      const char* aCategory, TracingKind aKind,
+      const Maybe<std::string>& aDocShellId = Nothing(),
+      const Maybe<uint32_t>& aDocShellHistoryId = Nothing(),
+      UniqueProfilerBacktrace aCause = nullptr);
+
+  MFBT_API ~TracingMarkerPayload() override;
 
   DECL_BASE_STREAM_PAYLOAD
 
  private:
+  MFBT_API TracingMarkerPayload(CommonProps&& aCommonProps,
+                                const char* aCategory, TracingKind aKind);
+
   const char* mCategory;
   TracingKind mKind;
 };
 
 class FileIOMarkerPayload : public ProfilerMarkerPayload {
  public:
-  FileIOMarkerPayload(const char* aOperation, const char* aSource,
-                      const char* aFilename, const TimeStamp& aStartTime,
-                      const TimeStamp& aEndTime, UniqueProfilerBacktrace aStack)
-      : ProfilerMarkerPayload(aStartTime, aEndTime, Nothing(), Nothing(),
-                              std::move(aStack)),
-        mSource(aSource),
-        mOperation(aOperation ? strdup(aOperation) : nullptr),
-        mFilename(aFilename ? strdup(aFilename) : nullptr) {
-    MOZ_ASSERT(aSource);
-  }
+  MFBT_API FileIOMarkerPayload(const char* aOperation, const char* aSource,
+                               const char* aFilename,
+                               const TimeStamp& aStartTime,
+                               const TimeStamp& aEndTime,
+                               UniqueProfilerBacktrace aStack);
+
+  MFBT_API ~FileIOMarkerPayload() override;
 
   DECL_BASE_STREAM_PAYLOAD
 
  private:
+  MFBT_API FileIOMarkerPayload(CommonProps&& aCommonProps, const char* aSource,
+                               UniqueFreePtr<char>&& aOperation,
+                               UniqueFreePtr<char>&& aFilename);
+
   const char* mSource;
   UniqueFreePtr<char> mOperation;
   UniqueFreePtr<char> mFilename;
@@ -135,31 +222,29 @@ class FileIOMarkerPayload : public ProfilerMarkerPayload {
 
 class UserTimingMarkerPayload : public ProfilerMarkerPayload {
  public:
-  UserTimingMarkerPayload(const std::string& aName, const TimeStamp& aStartTime,
-                          const Maybe<std::string>& aDocShellId,
-                          const Maybe<uint32_t>& aDocShellHistoryId)
-      : ProfilerMarkerPayload(aStartTime, aStartTime, aDocShellId,
-                              aDocShellHistoryId),
-        mEntryType("mark"),
-        mName(aName) {}
+  MFBT_API UserTimingMarkerPayload(const std::string& aName,
+                                   const TimeStamp& aStartTime,
+                                   const Maybe<std::string>& aDocShellId,
+                                   const Maybe<uint32_t>& aDocShellHistoryId);
 
-  UserTimingMarkerPayload(const std::string& aName,
-                          const Maybe<std::string>& aStartMark,
-                          const Maybe<std::string>& aEndMark,
-                          const TimeStamp& aStartTime,
-                          const TimeStamp& aEndTime,
-                          const Maybe<std::string>& aDocShellId,
-                          const Maybe<uint32_t>& aDocShellHistoryId)
-      : ProfilerMarkerPayload(aStartTime, aEndTime, aDocShellId,
-                              aDocShellHistoryId),
-        mEntryType("measure"),
-        mName(aName),
-        mStartMark(aStartMark),
-        mEndMark(aEndMark) {}
+  MFBT_API UserTimingMarkerPayload(const std::string& aName,
+                                   const Maybe<std::string>& aStartMark,
+                                   const Maybe<std::string>& aEndMark,
+                                   const TimeStamp& aStartTime,
+                                   const TimeStamp& aEndTime,
+                                   const Maybe<std::string>& aDocShellId,
+                                   const Maybe<uint32_t>& aDocShellHistoryId);
+
+  MFBT_API ~UserTimingMarkerPayload() override;
 
   DECL_BASE_STREAM_PAYLOAD
 
  private:
+  MFBT_API UserTimingMarkerPayload(CommonProps&& aCommonProps,
+                                   const char* aEntryType, std::string&& aName,
+                                   Maybe<std::string>&& aStartMark,
+                                   Maybe<std::string>&& aEndMark);
+
   // Either "mark" or "measure".
   const char* mEntryType;
   std::string mName;
@@ -169,68 +254,129 @@ class UserTimingMarkerPayload : public ProfilerMarkerPayload {
 
 class HangMarkerPayload : public ProfilerMarkerPayload {
  public:
-  HangMarkerPayload(const TimeStamp& aStartTime, const TimeStamp& aEndTime)
-      : ProfilerMarkerPayload(aStartTime, aEndTime) {}
+  MFBT_API HangMarkerPayload(const TimeStamp& aStartTime,
+                             const TimeStamp& aEndTime);
+
+  MFBT_API ~HangMarkerPayload() override;
 
   DECL_BASE_STREAM_PAYLOAD
+
  private:
+  MFBT_API explicit HangMarkerPayload(CommonProps&& aCommonProps);
 };
 
 class LongTaskMarkerPayload : public ProfilerMarkerPayload {
  public:
-  LongTaskMarkerPayload(const TimeStamp& aStartTime, const TimeStamp& aEndTime)
-      : ProfilerMarkerPayload(aStartTime, aEndTime) {}
+  MFBT_API LongTaskMarkerPayload(const TimeStamp& aStartTime,
+                                 const TimeStamp& aEndTime);
 
-  DECL_BASE_STREAM_PAYLOAD
-};
-
-class TextMarkerPayload : public ProfilerMarkerPayload {
- public:
-  TextMarkerPayload(const std::string& aText, const TimeStamp& aStartTime)
-      : ProfilerMarkerPayload(aStartTime, aStartTime), mText(aText) {}
-
-  TextMarkerPayload(const std::string& aText, const TimeStamp& aStartTime,
-                    const TimeStamp& aEndTime)
-      : ProfilerMarkerPayload(aStartTime, aEndTime), mText(aText) {}
-
-  TextMarkerPayload(const std::string& aText, const TimeStamp& aStartTime,
-                    const Maybe<std::string>& aDocShellId,
-                    const Maybe<uint32_t>& aDocShellHistoryId)
-      : ProfilerMarkerPayload(aStartTime, aStartTime, aDocShellId,
-                              aDocShellHistoryId),
-        mText(aText) {}
-
-  TextMarkerPayload(const std::string& aText, const TimeStamp& aStartTime,
-                    const TimeStamp& aEndTime,
-                    const Maybe<std::string>& aDocShellId,
-                    const Maybe<uint32_t>& aDocShellHistoryId,
-                    UniqueProfilerBacktrace aCause = nullptr)
-      : ProfilerMarkerPayload(aStartTime, aEndTime, aDocShellId,
-                              aDocShellHistoryId, std::move(aCause)),
-        mText(aText) {}
+  MFBT_API ~LongTaskMarkerPayload() override;
 
   DECL_BASE_STREAM_PAYLOAD
 
  private:
+  MFBT_API explicit LongTaskMarkerPayload(CommonProps&& aCommonProps);
+};
+
+class TextMarkerPayload : public ProfilerMarkerPayload {
+ public:
+  MFBT_API TextMarkerPayload(const std::string& aText,
+                             const TimeStamp& aStartTime);
+
+  MFBT_API TextMarkerPayload(const std::string& aText,
+                             const TimeStamp& aStartTime,
+                             const TimeStamp& aEndTime);
+
+  MFBT_API TextMarkerPayload(const std::string& aText,
+                             const TimeStamp& aStartTime,
+                             const Maybe<std::string>& aDocShellId,
+                             const Maybe<uint32_t>& aDocShellHistoryId);
+
+  MFBT_API TextMarkerPayload(const std::string& aText,
+                             const TimeStamp& aStartTime,
+                             const TimeStamp& aEndTime,
+                             const Maybe<std::string>& aDocShellId,
+                             const Maybe<uint32_t>& aDocShellHistoryId,
+                             UniqueProfilerBacktrace aCause = nullptr);
+
+  MFBT_API ~TextMarkerPayload() override;
+
+  DECL_BASE_STREAM_PAYLOAD
+
+ private:
+  MFBT_API TextMarkerPayload(CommonProps&& aCommonProps, std::string&& aText);
+
   std::string mText;
 };
 
 class LogMarkerPayload : public ProfilerMarkerPayload {
  public:
-  LogMarkerPayload(const char* aModule, const char* aText,
-                   const TimeStamp& aStartTime)
-      : ProfilerMarkerPayload(aStartTime, aStartTime),
-        mModule(aModule),
-        mText(aText) {}
+  MFBT_API LogMarkerPayload(const char* aModule, const char* aText,
+                            const TimeStamp& aStartTime);
+
+  MFBT_API ~LogMarkerPayload() override;
 
   DECL_BASE_STREAM_PAYLOAD
 
  private:
+  MFBT_API LogMarkerPayload(CommonProps&& aCommonProps, std::string&& aModule,
+                            std::string&& aText);
+
   std::string mModule;  // longest known LazyLogModule name is ~24
   std::string mText;
 };
 
 }  // namespace baseprofiler
+
+// Serialize a pointed-at ProfilerMarkerPayload, may be null when there are no
+// payloads.
+template <>
+struct BlocksRingBuffer::Serializer<
+    const baseprofiler::ProfilerMarkerPayload*> {
+  static Length Bytes(const baseprofiler::ProfilerMarkerPayload* aPayload) {
+    return baseprofiler::ProfilerMarkerPayload::TagAndSerializationBytes(
+        aPayload);
+  }
+
+  static void Write(EntryWriter& aEW,
+                    const baseprofiler::ProfilerMarkerPayload* aPayload) {
+    baseprofiler::ProfilerMarkerPayload::TagAndSerialize(aPayload, aEW);
+  }
+};
+
+// Serialize a pointed-at ProfilerMarkerPayload, may be null for no payloads.
+template <>
+struct BlocksRingBuffer::Serializer<
+    UniquePtr<baseprofiler::ProfilerMarkerPayload>> {
+  static Length Bytes(
+      const UniquePtr<baseprofiler::ProfilerMarkerPayload>& aPayload) {
+    return baseprofiler::ProfilerMarkerPayload::TagAndSerializationBytes(
+        aPayload.get());
+  }
+
+  static void Write(
+      EntryWriter& aEW,
+      const UniquePtr<baseprofiler::ProfilerMarkerPayload>& aPayload) {
+    baseprofiler::ProfilerMarkerPayload::TagAndSerialize(aPayload.get(), aEW);
+  }
+};
+
+// Deserialize a ProfilerMarkerPayload into a UniquePtr, may be null if there
+// are no payloads.
+template <>
+struct BlocksRingBuffer::Deserializer<
+    UniquePtr<baseprofiler::ProfilerMarkerPayload>> {
+  static void ReadInto(
+      EntryReader& aER,
+      UniquePtr<baseprofiler::ProfilerMarkerPayload>& aPayload) {
+    aPayload = Read(aER);
+  }
+
+  static UniquePtr<baseprofiler::ProfilerMarkerPayload> Read(EntryReader& aER) {
+    return baseprofiler::ProfilerMarkerPayload::DeserializeTagAndPayload(aER);
+  }
+};
+
 }  // namespace mozilla
 
 #endif  // BaseProfilerMarkerPayload_h
diff --git a/mozglue/baseprofiler/public/BlocksRingBuffer.h b/mozglue/baseprofiler/public/BlocksRingBuffer.h
new file mode 100644
index 0000000000..0ed2020fa0
--- /dev/null
+++ b/mozglue/baseprofiler/public/BlocksRingBuffer.h
@@ -0,0 +1,1971 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef BlocksRingBuffer_h
+#define BlocksRingBuffer_h
+
+#include "mozilla/DebugOnly.h"
+#include "mozilla/BaseProfilerDetail.h"
+#include "mozilla/ModuloBuffer.h"
+#include "mozilla/Unused.h"
+
+#include "mozilla/Maybe.h"
+#include "mozilla/Span.h"
+#include "mozilla/Tuple.h"
+#include "mozilla/UniquePtrExtensions.h"
+#include "mozilla/Variant.h"
+
+#include <functional>
+#include <string>
+#include <tuple>
+#include <utility>
+
+namespace mozilla {
+
+// Thread-safe Ring buffer that can store blocks of different sizes during
+// defined sessions.
+// Each *block* contains an *entry* and the entry size:
+// [ entry_size | entry ] [ entry_size | entry ] ...
+// *In-session* is a period of time during which `BlocksRingBuffer` allows
+// reading and writing. *Out-of-session*, the `BlocksRingBuffer` object is
+// still valid, but contains no data, and gracefully denies accesses.
+//
+// To write an entry, the buffer reserves a block of sufficient size (to contain
+// user data of predetermined size), writes the entry size, and lets the caller
+// fill the entry contents using ModuloBuffer::Iterator APIs and a few entry-
+// specific APIs. E.g.:
+// ```
+// BlockRingsBuffer brb(PowerOfTwo<BlockRingsBuffer::Length>(1024));
+// brb.ReserveAndPut([]() { return sizeof(123); },
+//                   [&](BlocksRingBuffer::EntryWriter& aEW) {
+//                     aEW.WriteObject(123);
+//                   });
+// ```
+// Other `Put...` functions may be used as shortcuts for simple entries.
+// The objects given to the caller's callbacks should only be used inside the
+// callbacks and not stored elsewhere, because they keep their own references to
+// the BlocksRingBuffer and therefore should not live longer.
+// Different type of objects may be serialized into an entry, see `Serializer`
+// for more information.
+//
+// When reading data, the buffer iterates over blocks (it knows how to read the
+// entry size, and therefore move to the next block), and lets the caller read
+// the entry inside of each block. E.g.:
+// ```
+// brb.Read([](BlocksRingBuffer::Reader aR) {}
+//   for (BlocksRingBuffer::EntryReader aER : aR) {
+//     /* Use EntryReader functions to read back serialized objects. */
+//     int n = aER.ReadObject<int>();
+//   }
+// });
+// ```
+// Different type of objects may be deserialized from an entry, see
+// `Deserializer` for more information.
+//
+// The caller may retrieve the `BlockIndex` corresponding to an entry
+// (`BlockIndex` is an opaque type preventing the user from modifying it). That
+// index may later be used to get back to that particular entry if it still
+// exists.
+class BlocksRingBuffer {
+  // Near-infinite index type, not expecting overflow.
+  using Index = uint64_t;
+
+ public:
+  // Using ModuloBuffer as underlying circular byte buffer.
+  using Buffer = ModuloBuffer<uint32_t, Index>;
+  using Byte = Buffer::Byte;
+  using BufferWriter = Buffer::Writer;
+  using BufferReader = Buffer::Reader;
+
+  // Length type for total buffer (as PowerOfTwo<Length>) and each entry.
+  using Length = uint32_t;
+
+  // Class to be specialized for types to be written in a BlocksRingBuffer.
+  // See common specializations at the bottom of this header.
+  // The following static functions must be provided:
+  //   static Length Bytes(const T& aT) {
+  //     /* Return number of bytes that will be written. */
+  //   }
+  //   static void Write(EntryWriter& aEW,
+  //                     const T& aT) {
+  //     /* Call `aEW.WriteX(...)` functions to serialize aT, be sure to write
+  //        exactly `Bytes(aT)` bytes! */
+  //   }
+  template <typename T>
+  struct Serializer;
+
+  // Class to be specialized for types to be read from a BlocksRingBuffer.
+  // See common specializations at the bottom of this header.
+  // The following static functions must be provided:
+  //   static void ReadInto(EntryReader aER&, T& aT)
+  //   {
+  //     /* Call `aER.ReadX(...)` function to deserialize into aT, be sure to
+  //        read exactly `Bytes(aT)`! */
+  //   }
+  //   static T Read(EntryReader& aER) {
+  //     /* Call `aER.ReadX(...)` function to deserialize and return a `T`, be
+  //        sure to read exactly `Bytes(returned value)`! */
+  //   }
+  template <typename T>
+  struct Deserializer;
+
+  // Externally-opaque class encapsulating a block index.
+  // User may get these from some BlocksRingBuffer functions, to later use them
+  // to access previous blocks using `GetEntryAt(BlockIndex)` functions.
+  class BlockIndex {
+   public:
+    // Default constructor with internal 0 value, for which BlocksRingBuffer
+    // guarantees that it is before any valid entries. All public APIs should
+    // fail gracefully, doing nothing and/or returning Nothing. It may be used
+    // to initialize a BlockIndex variable that will be overwritten with a real
+    // value (e.g., from `ReadObject()`, `CurrentBlockIndex()`, etc.).
+    BlockIndex() : mBlockIndex(0) {}
+
+    // Explicit conversion to bool, works in `if/while()` tests.
+    // Only returns false for default `BlockIndex{}` value.
+    explicit operator bool() const { return mBlockIndex != 0; }
+
+    // Comparison over the wide `Index` range, ignoring wrapping of the
+    // containing ring buffer.
+    bool operator==(const BlockIndex& aRhs) const {
+      return mBlockIndex == aRhs.mBlockIndex;
+    }
+    bool operator!=(const BlockIndex& aRhs) const {
+      return mBlockIndex != aRhs.mBlockIndex;
+    }
+    bool operator<(const BlockIndex& aRhs) const {
+      return mBlockIndex < aRhs.mBlockIndex;
+    }
+    bool operator<=(const BlockIndex& aRhs) const {
+      return mBlockIndex <= aRhs.mBlockIndex;
+    }
+    bool operator>(const BlockIndex& aRhs) const {
+      return mBlockIndex > aRhs.mBlockIndex;
+    }
+    bool operator>=(const BlockIndex& aRhs) const {
+      return mBlockIndex >= aRhs.mBlockIndex;
+    }
+
+    // Temporary escape hatches to let legacy code access block indices.
+    // TODO: Remove this when legacy code has been modernized.
+    uint64_t ConvertToU64() const { return uint64_t(mBlockIndex); }
+    static BlockIndex ConvertFromU64(uint64_t aIndex) {
+      return BlockIndex(Index(aIndex));
+    }
+
+   private:
+    // Only BlocksRingBuffer internal functions and serializers can convert
+    // between `BlockIndex` and `Index`.
+    friend class BlocksRingBuffer;
+    explicit BlockIndex(Index aBlockIndex) : mBlockIndex(aBlockIndex) {}
+    explicit operator Index() const { return mBlockIndex; }
+
+    Index mBlockIndex;
+  };
+
+  enum class ThreadSafety { WithoutMutex, WithMutex };
+
+  // Default constructor starts out-of-session (nothing to read or write).
+  explicit BlocksRingBuffer(ThreadSafety aThreadSafety)
+      : mMutex(aThreadSafety != ThreadSafety::WithoutMutex) {}
+
+  // Create a buffer of the given length.
+  explicit BlocksRingBuffer(ThreadSafety aThreadSafety,
+                            PowerOfTwo<Length> aLength)
+      : mMutex(aThreadSafety != ThreadSafety::WithoutMutex),
+        mMaybeUnderlyingBuffer(Some(UnderlyingBuffer(aLength))) {}
+
+  // Take ownership of an existing buffer.
+  BlocksRingBuffer(ThreadSafety aThreadSafety,
+                   UniquePtr<Buffer::Byte[]> aExistingBuffer,
+                   PowerOfTwo<Length> aLength)
+      : mMutex(aThreadSafety != ThreadSafety::WithoutMutex),
+        mMaybeUnderlyingBuffer(
+            Some(UnderlyingBuffer(std::move(aExistingBuffer), aLength))) {}
+
+  // Use an externally-owned buffer.
+  BlocksRingBuffer(ThreadSafety aThreadSafety, Buffer::Byte* aExternalBuffer,
+                   PowerOfTwo<Length> aLength)
+      : mMutex(aThreadSafety != ThreadSafety::WithoutMutex),
+        mMaybeUnderlyingBuffer(
+            Some(UnderlyingBuffer(aExternalBuffer, aLength))) {}
+
+  // Destructor doesn't need to do anything special. (Clearing entries would
+  // only update indices and stats, which won't be accessible after the object
+  // is destroyed anyway.)
+  ~BlocksRingBuffer() = default;
+
+  // Remove underlying buffer, if any.
+  void Reset() {
+    baseprofiler::detail::BaseProfilerMaybeAutoLock lock(mMutex);
+    ResetUnderlyingBuffer();
+  }
+
+  // Create a buffer of the given length.
+  void Set(PowerOfTwo<Length> aLength) {
+    baseprofiler::detail::BaseProfilerMaybeAutoLock lock(mMutex);
+    ResetUnderlyingBuffer();
+    mMaybeUnderlyingBuffer.emplace(aLength);
+  }
+
+  // Take ownership of an existing buffer.
+  void Set(UniquePtr<Buffer::Byte[]> aExistingBuffer,
+           PowerOfTwo<Length> aLength) {
+    baseprofiler::detail::BaseProfilerMaybeAutoLock lock(mMutex);
+    ResetUnderlyingBuffer();
+    mMaybeUnderlyingBuffer.emplace(std::move(aExistingBuffer), aLength);
+  }
+
+  // Use an externally-owned buffer.
+  void Set(Buffer::Byte* aExternalBuffer, PowerOfTwo<Length> aLength) {
+    baseprofiler::detail::BaseProfilerMaybeAutoLock lock(mMutex);
+    ResetUnderlyingBuffer();
+    mMaybeUnderlyingBuffer.emplace(aExternalBuffer, aLength);
+  }
+
+  bool IsThreadSafe() const { return mMutex.IsActivated(); }
+
+  // Lock the buffer mutex and run the provided callback.
+  // This can be useful when the caller needs to explicitly lock down this
+  // buffer, but not do anything else with it.
+  template <typename Callback>
+  auto LockAndRun(Callback&& aCallback) const {
+    baseprofiler::detail::BaseProfilerMaybeAutoLock lock(mMutex);
+    return std::forward<Callback>(aCallback)();
+  }
+
+  // Buffer length in bytes.
+  Maybe<PowerOfTwo<Length>> BufferLength() const {
+    baseprofiler::detail::BaseProfilerMaybeAutoLock lock(mMutex);
+    return mMaybeUnderlyingBuffer.map([](const UnderlyingBuffer& aBuffer) {
+      return aBuffer.mBuffer.BufferLength();
+    });
+    ;
+  }
+
+  // Size of external resources.
+  size_t SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const {
+    if (!mMaybeUnderlyingBuffer) {
+      return 0;
+    }
+    return mMaybeUnderlyingBuffer->mBuffer.SizeOfExcludingThis(aMallocSizeOf);
+  }
+
+  size_t SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const {
+    return aMallocSizeOf(this) + SizeOfExcludingThis(aMallocSizeOf);
+  }
+
+  // Snapshot of the buffer state.
+  struct State {
+    // Index to the first block.
+    BlockIndex mRangeStart;
+
+    // Index past the last block. Equals mRangeStart if empty.
+    BlockIndex mRangeEnd;
+
+    // Number of blocks that have been pushed into this buffer.
+    uint64_t mPushedBlockCount = 0;
+
+    // Number of blocks that have been removed from this buffer.
+    // Note: Live entries = pushed - cleared.
+    uint64_t mClearedBlockCount = 0;
+  };
+
+  // Get a snapshot of the current state.
+  // When out-of-session, mFirstReadIndex==mNextWriteIndex, and
+  // mPushedBlockCount==mClearedBlockCount==0.
+  // Note that these may change right after this thread-safe call, so they
+  // should only be used for statistical purposes.
+  State GetState() const {
+    baseprofiler::detail::BaseProfilerMaybeAutoLock lock(mMutex);
+    return {
+        mFirstReadIndex, mNextWriteIndex,
+        mMaybeUnderlyingBuffer ? mMaybeUnderlyingBuffer->mPushedBlockCount : 0,
+        mMaybeUnderlyingBuffer ? mMaybeUnderlyingBuffer->mClearedBlockCount
+                               : 0};
+  }
+
+  // No objects, no bytes! (May be useful for generic programming.)
+  static Length SumBytes() { return 0; }
+
+  // Number of bytes needed to serialize objects.
+  template <typename T0, typename... Ts>
+  static Length SumBytes(const T0& aT0, const Ts&... aTs) {
+    return Serializer<T0>::Bytes(aT0) + SumBytes(aTs...);
+  }
+
+  // Iterator-like class used to read from an entry.
+  // Created through `BlockIterator`, or a `GetEntryAt()` function, lives
+  // within a lock guard lifetime.
+  class EntryReader : public BufferReader {
+   public:
+    // Allow move-construction.
+    EntryReader(EntryReader&& aOther) = default;
+    // Disallow copying and assignments.
+    EntryReader(const EntryReader& aOther) = delete;
+    EntryReader& operator=(const EntryReader& aOther) = delete;
+    EntryReader& operator=(EntryReader&& aOther) = delete;
+
+#ifdef DEBUG
+    ~EntryReader() {
+      // Expect reader to stay within the entry.
+      MOZ_ASSERT(CurrentIndex() >= mEntryStart);
+      MOZ_ASSERT(CurrentIndex() <= mEntryStart + mEntryBytes);
+      // No EntryReader should live outside of a mutexed call.
+      mRing.mMutex.AssertCurrentThreadOwns();
+    }
+#endif  // DEBUG
+
+    // All BufferReader (aka ModuloBuffer<uint32_t, Index>::Reader) APIs are
+    // available to read data from this entry.
+    // Note that there are no bound checks! So this should not be used with
+    // external untrusted data.
+
+    // Total number of bytes in this entry.
+    Length EntryBytes() const { return mEntryBytes; }
+
+    // Current position of this iterator in the entry.
+    Length IndexInEntry() const {
+      return static_cast<Length>(CurrentIndex() - mEntryStart);
+    }
+
+    // Number of bytes left in this entry after this iterator.
+    Length RemainingBytes() const {
+      return static_cast<Length>(mEntryStart + mEntryBytes - CurrentIndex());
+    }
+
+    template <typename T>
+    void ReadIntoObject(T& aObject) {
+      DebugOnly<Length> start = IndexInEntry();
+      Deserializer<T>::ReadInto(*this, aObject);
+      // Make sure the helper moved the iterator as expected.
+      MOZ_ASSERT(IndexInEntry() == start + SumBytes(aObject));
+    }
+
+    // Allow `EntryReader::ReadIntoObjects()` with nothing, this could be
+    // useful for generic programming.
+    void ReadIntoObjects() {}
+
+    // Read into one or more objects, sequentially.
+    template <typename T0, typename... Ts>
+    void ReadIntoObjects(T0& aT0, Ts&... aTs) {
+      ReadIntoObject(aT0);
+      ReadIntoObjects(aTs...);
+    }
+
+    // Read data as an object and move iterator ahead.
+    template <typename T>
+    T ReadObject() {
+      DebugOnly<Length> start = IndexInEntry();
+      T ob = Deserializer<T>::Read(*this);
+      // Make sure the helper moved the iterator as expected.
+      MOZ_ASSERT(IndexInEntry() == start + SumBytes(ob));
+      return ob;
+    }
+
+    // Can be used as reference to come back to this entry with GetEntryAt().
+    BlockIndex CurrentBlockIndex() const {
+      return BlockIndex(mEntryStart - BufferReader::ULEB128Size(mEntryBytes));
+    }
+
+    // Index past the end of this block, which is the start of the next block.
+    BlockIndex NextBlockIndex() const {
+      return BlockIndex(mEntryStart + mEntryBytes);
+    }
+
+    // Index of the first block in the whole buffer.
+    BlockIndex BufferRangeStart() const { return mRing.mFirstReadIndex; }
+
+    // Index past the last block in the whole buffer.
+    BlockIndex BufferRangeEnd() const { return mRing.mNextWriteIndex; }
+
+    // Get another entry based on a {Current,Next}BlockIndex(). This may fail if
+    // the buffer has already looped around and cleared that block, or for the
+    // one-past-the-end index.
+    Maybe<EntryReader> GetEntryAt(BlockIndex aBlockIndex) {
+      // Don't accept a not-yet-written index.
+      MOZ_ASSERT(aBlockIndex <= BufferRangeEnd());
+      if (aBlockIndex >= BufferRangeStart() && aBlockIndex < BufferRangeEnd()) {
+        // Block is still alive -> Return reader for it.
+        mRing.AssertBlockIndexIsValid(aBlockIndex);
+        return Some(EntryReader(mRing, aBlockIndex));
+      }
+      // Block has been overwritten/cleared.
+      return Nothing();
+    }
+
+    // Get the next entry. This may fail if this is already the last entry.
+    Maybe<EntryReader> GetNextEntry() {
+      const BlockIndex nextBlockIndex = NextBlockIndex();
+      if (nextBlockIndex < BufferRangeEnd()) {
+        return Some(EntryReader(mRing, nextBlockIndex));
+      }
+      return Nothing();
+    }
+
+   private:
+    // Only a BlocksRingBuffer can instantiate an EntryReader.
+    friend class BlocksRingBuffer;
+
+    explicit EntryReader(const BlocksRingBuffer& aRing, BlockIndex aBlockIndex)
+        : BufferReader(aRing.mMaybeUnderlyingBuffer->mBuffer.ReaderAt(
+              Index(aBlockIndex))),
+          mRing(aRing),
+          mEntryBytes(BufferReader::ReadULEB128<Length>()),
+          mEntryStart(CurrentIndex()) {
+      // No EntryReader should live outside of a mutexed call.
+      mRing.mMutex.AssertCurrentThreadOwns();
+    }
+
+    // Using a non-null pointer instead of a reference, to allow copying.
+    // This EntryReader should only live inside one of the thread-safe
+    // BlocksRingBuffer functions, for this reference to stay valid.
+    const BlocksRingBuffer& mRing;
+    const Length mEntryBytes;
+    const Index mEntryStart;
+  };
+
+  class Reader;
+
+  // Class that can iterate through blocks and provide `EntryReader`s.
+  // Created through `Reader`, lives within a lock guard lifetime.
+  class BlockIterator {
+   public:
+#ifdef DEBUG
+    ~BlockIterator() {
+      // No BlockIterator should live outside of a mutexed call.
+      mRing->mMutex.AssertCurrentThreadOwns();
+    }
+#endif  // DEBUG
+
+    // Comparison with other iterator, mostly used in range-for loops.
+    bool operator==(const BlockIterator aRhs) const {
+      MOZ_ASSERT(mRing == aRhs.mRing);
+      return mBlockIndex == aRhs.mBlockIndex;
+    }
+    bool operator!=(const BlockIterator aRhs) const {
+      MOZ_ASSERT(mRing == aRhs.mRing);
+      return mBlockIndex != aRhs.mBlockIndex;
+    }
+
+    // Advance to next BlockIterator.
+    BlockIterator& operator++() {
+      mBlockIndex = NextBlockIndex();
+      return *this;
+    }
+
+    // Dereferencing creates an `EntryReader` for the entry inside this block.
+    EntryReader operator*() const {
+      return mRing->ReaderInBlockAt(mBlockIndex);
+    }
+
+    // True if this iterator is just past the last entry.
+    bool IsAtEnd() const {
+      MOZ_ASSERT(mBlockIndex <= BufferRangeEnd());
+      return mBlockIndex == BufferRangeEnd();
+    }
+
+    // Can be used as reference to come back to this entry with `GetEntryAt()`.
+    BlockIndex CurrentBlockIndex() const { return mBlockIndex; }
+
+    // Index past the end of this block, which is the start of the next block.
+    BlockIndex NextBlockIndex() const {
+      MOZ_ASSERT(!IsAtEnd());
+      BufferReader reader =
+          mRing->mMaybeUnderlyingBuffer->mBuffer.ReaderAt(Index(mBlockIndex));
+      Length entrySize = reader.ReadULEB128<Length>();
+      return BlockIndex(reader.CurrentIndex() + entrySize);
+    }
+
+    // Index of the first block in the whole buffer.
+    BlockIndex BufferRangeStart() const { return mRing->mFirstReadIndex; }
+
+    // Index past the last block in the whole buffer.
+    BlockIndex BufferRangeEnd() const { return mRing->mNextWriteIndex; }
+
+   private:
+    // Only a Reader can instantiate a BlockIterator.
+    friend class Reader;
+
+    BlockIterator(const BlocksRingBuffer& aRing, BlockIndex aBlockIndex)
+        : mRing(WrapNotNull(&aRing)), mBlockIndex(aBlockIndex) {
+      // No BlockIterator should live outside of a mutexed call.
+      mRing->mMutex.AssertCurrentThreadOwns();
+    }
+
+    // Using a non-null pointer instead of a reference, to allow copying.
+    // This BlockIterator should only live inside one of the thread-safe
+    // BlocksRingBuffer functions, for this reference to stay valid.
+    NotNull<const BlocksRingBuffer*> mRing;
+    BlockIndex mBlockIndex;
+  };
+
+  // Class that can create `BlockIterator`s (e.g., for range-for), or just
+  // iterate through entries; lives within a lock guard lifetime.
+  class MOZ_RAII Reader {
+   public:
+    Reader(const Reader&) = delete;
+    Reader& operator=(const Reader&) = delete;
+    Reader(Reader&&) = delete;
+    Reader& operator=(Reader&&) = delete;
+
+#ifdef DEBUG
+    ~Reader() {
+      // No Reader should live outside of a mutexed call.
+      mRing.mMutex.AssertCurrentThreadOwns();
+    }
+#endif  // DEBUG
+
+    // Index of the first block in the whole buffer.
+    BlockIndex BufferRangeStart() const { return mRing.mFirstReadIndex; }
+
+    // Index past the last block in the whole buffer.
+    BlockIndex BufferRangeEnd() const { return mRing.mNextWriteIndex; }
+
+    // Iterators to the first and past-the-last blocks.
+    // Compatible with range-for (see `ForEach` below as example).
+    BlockIterator begin() const {
+      return BlockIterator(mRing, BufferRangeStart());
+    }
+    // Note that a `BlockIterator` at the `end()` should not be dereferenced, as
+    // there is no actual block there!
+    BlockIterator end() const { return BlockIterator(mRing, BufferRangeEnd()); }
+
+    // Get a `BlockIterator` at the given `BlockIndex`, clamped to the stored
+    // range. Note that a `BlockIterator` at the `end()` should not be
+    // dereferenced, as there is no actual block there!
+    BlockIterator At(BlockIndex aBlockIndex) const {
+      if (aBlockIndex < BufferRangeStart()) {
+        // Anything before the range (including null BlockIndex) is clamped at
+        // the beginning.
+        return begin();
+      }
+      // Otherwise we at least expect the index to be valid (pointing exactly at
+      // a live block, or just past the end.)
+      mRing.AssertBlockIndexIsValidOrEnd(aBlockIndex);
+      return BlockIterator(mRing, aBlockIndex);
+    }
+
+    // Run `aCallback(EntryReader&)` on each entry from first to last.
+    // Callback should not store `EntryReader`, as it may become invalid after
+    // this thread-safe call.
+    template <typename Callback>
+    void ForEach(Callback&& aCallback) const {
+      for (EntryReader reader : *this) {
+        aCallback(reader);
+      }
+    }
+
+   private:
+    friend class BlocksRingBuffer;
+
+    explicit Reader(const BlocksRingBuffer& aRing) : mRing(aRing) {
+      // No Reader should live outside of a mutexed call.
+      mRing.mMutex.AssertCurrentThreadOwns();
+    }
+
+    // This Reader should only live inside one of the thread-safe
+    // BlocksRingBuffer functions, for this reference to stay valid.
+    const BlocksRingBuffer& mRing;
+  };
+
+  // Call `aCallback(BlocksRingBuffer::Reader*)` (nullptr when out-of-session),
+  // and return whatever `aCallback` returns. Callback should not store
+  // `Reader`, because it may become invalid after this call.
+  template <typename Callback>
+  auto Read(Callback&& aCallback) const {
+    {
+      baseprofiler::detail::BaseProfilerMaybeAutoLock lock(mMutex);
+      if (MOZ_LIKELY(mMaybeUnderlyingBuffer)) {
+        Reader reader(*this);
+        return std::forward<Callback>(aCallback)(&reader);
+      }
+    }
+    return std::forward<Callback>(aCallback)(nullptr);
+  }
+
+  // Call `aCallback(BlocksRingBuffer::EntryReader&)` on each item.
+  // Callback should not store `EntryReader`, because it may become invalid
+  // after this call.
+  template <typename Callback>
+  void ReadEach(Callback&& aCallback) const {
+    Read([&](Reader* aReader) {
+      if (MOZ_LIKELY(aReader)) {
+        aReader->ForEach(aCallback);
+      }
+    });
+  }
+
+  // Call `aCallback(Maybe<BlocksRingBuffer::EntryReader>&&)` on the entry at
+  // the given BlockIndex; The `Maybe` will be `Nothing` if out-of-session, or
+  // if that entry doesn't exist anymore, or if we've reached just past the
+  // last entry. Return whatever `aCallback` returns. Callback should not
+  // store `EntryReader`, because it may become invalid after this call.
+  template <typename Callback>
+  auto ReadAt(BlockIndex aBlockIndex, Callback&& aCallback) const {
+    baseprofiler::detail::BaseProfilerMaybeAutoLock lock(mMutex);
+    MOZ_ASSERT(aBlockIndex <= mNextWriteIndex);
+    Maybe<EntryReader> maybeEntryReader;
+    if (MOZ_LIKELY(mMaybeUnderlyingBuffer) && aBlockIndex >= mFirstReadIndex &&
+        aBlockIndex < mNextWriteIndex) {
+      AssertBlockIndexIsValid(aBlockIndex);
+      maybeEntryReader.emplace(ReaderInBlockAt(aBlockIndex));
+    }
+    return std::forward<Callback>(aCallback)(std::move(maybeEntryReader));
+  }
+
+  // Class used to write an entry contents.
+  // Created through `Put()`, lives within a lock guard lifetime.
+  class MOZ_RAII EntryWriter : public BufferWriter {
+   public:
+    // Disallow copying, moving, and assignments.
+    EntryWriter(const EntryWriter& aOther) = delete;
+    EntryWriter& operator=(const EntryWriter& aOther) = delete;
+    EntryWriter(EntryWriter&& aOther) = delete;
+    EntryWriter& operator=(EntryWriter&& aOther) = delete;
+
+#ifdef DEBUG
+    ~EntryWriter() {
+      // We expect the caller to completely fill the entry.
+      // (Or at least pretend to, by moving this iterator to the end.)
+      MOZ_ASSERT(RemainingBytes() == 0);
+      // No EntryWriter should live outside of a mutexed call.
+      mRing.mMutex.AssertCurrentThreadOwns();
+    }
+#endif  // DEBUG
+
+    // All BufferWriter (aka ModuloBuffer<uint32_t, Index>::Writer) APIs are
+    // available to read/write data from/to this entry.
+    // Note that there are no bound checks! So this should not be used with
+    // external data.
+
+    // Total number of bytes in this entry.
+    Length EntryBytes() const { return mEntryBytes; }
+
+    // Current position of this iterator in the entry.
+    Length IndexInEntry() const {
+      return static_cast<Length>(CurrentIndex() - mEntryStart);
+    }
+
+    // Number of bytes left in this entry after this iterator.
+    Length RemainingBytes() const {
+      return static_cast<Length>(mEntryStart + mEntryBytes - CurrentIndex());
+    }
+
+    template <typename T>
+    void WriteObject(const T& aObject) {
+      DebugOnly<Length> start = IndexInEntry();
+      Serializer<T>::Write(*this, aObject);
+      // Make sure the helper moved the iterator as expected.
+      MOZ_ASSERT(IndexInEntry() == start + SumBytes(aObject));
+    }
+
+    // Allow `EntryWrite::WriteObjects()` with nothing, this could be useful
+    // for generic programming.
+    void WriteObjects() {}
+
+    // Write one or more objects, sequentially.
+    template <typename T0, typename... Ts>
+    void WriteObjects(const T0& aT0, const Ts&... aTs) {
+      WriteObject(aT0);
+      WriteObjects(aTs...);
+    }
+
+    // Can be used as reference to come back to this entry with `GetEntryAt()`.
+    BlockIndex CurrentBlockIndex() const {
+      return BlockIndex(mEntryStart - BufferWriter::ULEB128Size(mEntryBytes));
+    }
+
+    // Index past the end of this block, which will be the start of the next
+    // block to be written.
+    BlockIndex BlockEndIndex() const {
+      return BlockIndex(mEntryStart + mEntryBytes);
+    }
+
+    // Index of the first block in the whole buffer.
+    BlockIndex BufferRangeStart() const { return mRing.mFirstReadIndex; }
+
+    // Index past the last block in the whole buffer.
+    BlockIndex BufferRangeEnd() const { return mRing.mNextWriteIndex; }
+
+    // Get another entry based on a {Current,Next}BlockIndex(). This may fail if
+    // the buffer has already looped around and cleared that block.
+    Maybe<EntryReader> GetEntryAt(BlockIndex aBlockIndex) {
+      // Don't accept a not-yet-written index.
+      MOZ_RELEASE_ASSERT(aBlockIndex < BufferRangeEnd());
+      if (aBlockIndex >= BufferRangeStart()) {
+        // Block is still alive -> Return reader for it.
+        mRing.AssertBlockIndexIsValid(aBlockIndex);
+        return Some(EntryReader(mRing, aBlockIndex));
+      }
+      // Block has been overwritten/cleared.
+      return Nothing();
+    }
+
+   private:
+    // Only a BlocksRingBuffer can instantiate an EntryWriter.
+    friend class BlocksRingBuffer;
+
+    // Compute space needed for a block that can contain an entry of size
+    // `aEntryBytes`.
+    static Length BlockSizeForEntrySize(Length aEntryBytes) {
+      return aEntryBytes +
+             static_cast<Length>(BufferWriter::ULEB128Size(aEntryBytes));
+    }
+
+    EntryWriter(BlocksRingBuffer& aRing, BlockIndex aBlockIndex,
+                Length aEntryBytes)
+        : BufferWriter(aRing.mMaybeUnderlyingBuffer->mBuffer.WriterAt(
+              Index(aBlockIndex))),
+          mRing(aRing),
+          mEntryBytes(aEntryBytes),
+          mEntryStart([&]() {
+            // BufferWriter is at `aBlockIndex`. Write the entry size...
+            BufferWriter::WriteULEB128(aEntryBytes);
+            // ... BufferWriter now at start of entry section.
+            return CurrentIndex();
+          }()) {
+      // No EntryWriter should live outside of a mutexed call.
+      mRing.mMutex.AssertCurrentThreadOwns();
+    }
+
+    // This EntryWriter should only live inside one of the thread-safe
+    // BlocksRingBuffer functions, for this reference to stay valid.
+    BlocksRingBuffer& mRing;
+    const Length mEntryBytes;
+    const Index mEntryStart;
+  };
+
+  // Main function to write entries.
+  // Reserve `aCallbackBytes()` bytes, call `aCallback()` with a pointer to an
+  // on-stack temporary EntryWriter (nullptr when out-of-session), and return
+  // whatever `aCallback` returns. Callback should not store `EntryWriter`,
+  // because it may become invalid after this thread-safe call.
+  // Note: `aCallbackBytes` is a callback instead of a simple value, to delay
+  // this potentially-expensive computation until after we're checked that we're
+  // in-session; use `Put(Length, Callback)` below if you know the size already.
+  template <typename CallbackBytes, typename Callback>
+  auto ReserveAndPut(CallbackBytes aCallbackBytes, Callback&& aCallback) {
+    {  // Locked block.
+      baseprofiler::detail::BaseProfilerMaybeAutoLock lock(mMutex);
+      if (MOZ_LIKELY(mMaybeUnderlyingBuffer)) {
+        const Length entryBytes = std::forward<CallbackBytes>(aCallbackBytes)();
+        const Length bufferBytes =
+            mMaybeUnderlyingBuffer->mBuffer.BufferLength().Value();
+        MOZ_RELEASE_ASSERT(
+            entryBytes <= bufferBytes - BufferWriter::ULEB128Size(entryBytes),
+            "Entry would wrap and overwrite itself");
+        // COmpute block size from the requested entry size.
+        const Length blockBytes =
+            EntryWriter::BlockSizeForEntrySize(entryBytes);
+        // We will put this new block at the end of the current buffer.
+        const BlockIndex blockIndex = mNextWriteIndex;
+        // Compute the end of this new block...
+        const Index blockEnd = Index(blockIndex) + blockBytes;
+        // ... which is where the following block will go.
+        mNextWriteIndex = BlockIndex(blockEnd);
+        while (blockEnd > Index(mFirstReadIndex) + bufferBytes) {
+          // About to trample on an old block.
+          EntryReader reader = ReaderInBlockAt(mFirstReadIndex);
+          mMaybeUnderlyingBuffer->mClearedBlockCount += 1;
+          MOZ_ASSERT(reader.CurrentIndex() <= Index(reader.NextBlockIndex()));
+          // Move the buffer reading start past this cleared block.
+          mFirstReadIndex = reader.NextBlockIndex();
+        }
+        mMaybeUnderlyingBuffer->mPushedBlockCount += 1;
+        // Finally, let aCallback write into the entry.
+        EntryWriter entryWriter(*this, blockIndex, entryBytes);
+        return std::forward<Callback>(aCallback)(&entryWriter);
+      }
+    }  // End of locked block.
+    // Out-of-session, just invoke the callback with nullptr, no need to hold
+    // the lock.
+    return std::forward<Callback>(aCallback)(nullptr);
+  }
+
+  // Add a new entry of known size, call `aCallback` with a pointer to a
+  // temporary EntryWriter (can be null when out-of-session), and return
+  // whatever `aCallback` returns. Callback should not store the `EntryWriter`,
+  // as it may become invalid after this thread-safe call.
+  template <typename Callback>
+  auto Put(Length aBytes, Callback&& aCallback) {
+    return ReserveAndPut([aBytes]() { return aBytes; },
+                         std::forward<Callback>(aCallback));
+  }
+
+  // Add a new entry copied from the given buffer, return block index.
+  BlockIndex PutFrom(const void* aSrc, Length aBytes) {
+    return ReserveAndPut([aBytes]() { return aBytes; },
+                         [&](EntryWriter* aEntryWriter) {
+                           if (MOZ_LIKELY(aEntryWriter)) {
+                             aEntryWriter->Write(aSrc, aBytes);
+                             return aEntryWriter->CurrentBlockIndex();
+                           }
+                           // Out-of-session, return "empty" BlockIndex.
+                           return BlockIndex{};
+                         });
+  }
+
+  // Add a new single entry with *all* given object (using a Serializer for
+  // each), return block index.
+  template <typename... Ts>
+  BlockIndex PutObjects(const Ts&... aTs) {
+    static_assert(sizeof...(Ts) > 0,
+                  "PutObjects must be given at least one object.");
+    return ReserveAndPut([&]() { return SumBytes(aTs...); },
+                         [&](EntryWriter* aEntryWriter) {
+                           if (MOZ_LIKELY(aEntryWriter)) {
+                             aEntryWriter->WriteObjects(aTs...);
+                             return aEntryWriter->CurrentBlockIndex();
+                           }
+                           // Out-of-session, return "empty" BlockIndex.
+                           return BlockIndex{};
+                         });
+  }
+
+  // Add a new entry copied from the given object, return block index.
+  template <typename T>
+  BlockIndex PutObject(const T& aOb) {
+    return PutObjects(aOb);
+  }
+
+  // Append the contents of another BlocksRingBuffer to this one.
+  BlockIndex AppendContents(const BlocksRingBuffer& aSrc) {
+    baseprofiler::detail::BaseProfilerMaybeAutoLock lock(mMutex);
+
+    if (MOZ_UNLIKELY(!mMaybeUnderlyingBuffer)) {
+      // We are out-of-session, could not append contents.
+      return BlockIndex{};
+    }
+
+    baseprofiler::detail::BaseProfilerMaybeAutoLock srcLock(aSrc.mMutex);
+
+    if (MOZ_UNLIKELY(!aSrc.mMaybeUnderlyingBuffer)) {
+      // The other BRB is out-of-session, nothing to copy, we're done.
+      return BlockIndex{};
+    }
+
+    const Index srcStartIndex = Index(aSrc.mFirstReadIndex);
+    const Index srcEndIndex = Index(aSrc.mNextWriteIndex);
+    const Length bytesToCopy = static_cast<Length>(srcEndIndex - srcStartIndex);
+
+    if (MOZ_UNLIKELY(bytesToCopy == 0)) {
+      // The other BRB is empty, nothing to copy, we're done.
+      return BlockIndex{};
+    }
+
+    const Length bufferBytes =
+        mMaybeUnderlyingBuffer->mBuffer.BufferLength().Value();
+
+    MOZ_RELEASE_ASSERT(bytesToCopy <= bufferBytes,
+                       "Entry would wrap and overwrite itself");
+
+    // We will put all copied blocks at the end of the current buffer.
+    const Index dstStartIndex = Index(mNextWriteIndex);
+    // Compute where the copy will end...
+    const Index dstEndIndex = dstStartIndex + bytesToCopy;
+    // ... which is where the following block will go.
+    mNextWriteIndex = BlockIndex(dstEndIndex);
+
+    while (dstEndIndex > Index(mFirstReadIndex) + bufferBytes) {
+      // About to trample on an old block.
+      EntryReader reader = ReaderInBlockAt(mFirstReadIndex);
+      mMaybeUnderlyingBuffer->mClearedBlockCount += 1;
+      MOZ_ASSERT(reader.CurrentIndex() <= Index(reader.NextBlockIndex()));
+      // Move the buffer reading start past this cleared block.
+      mFirstReadIndex = reader.NextBlockIndex();
+    }
+
+    // Update our pushed count with the number of live blocks we are copying.
+    mMaybeUnderlyingBuffer->mPushedBlockCount +=
+        aSrc.mMaybeUnderlyingBuffer->mPushedBlockCount -
+        aSrc.mMaybeUnderlyingBuffer->mClearedBlockCount;
+
+    const auto readerEnd =
+        aSrc.mMaybeUnderlyingBuffer->mBuffer.ReaderAt(srcEndIndex);
+    auto writer = mMaybeUnderlyingBuffer->mBuffer.WriterAt(dstStartIndex);
+    // Copy all the bytes. TODO: Optimize with memcpy's?
+    for (auto reader =
+             aSrc.mMaybeUnderlyingBuffer->mBuffer.ReaderAt(srcStartIndex);
+         reader != readerEnd; ++reader, ++writer) {
+      *writer = *reader;
+    }
+    MOZ_ASSERT(writer == mMaybeUnderlyingBuffer->mBuffer.WriterAt(
+                             Index(mNextWriteIndex)));
+
+    return BlockIndex(dstStartIndex);
+  }
+
+  // Clear all entries: Move read index to the end so that these entries cannot
+  // be read anymore.
+  void Clear() {
+    baseprofiler::detail::BaseProfilerMaybeAutoLock lock(mMutex);
+    ClearAllEntries();
+  }
+
+  // Clear all entries strictly before aBlockIndex, and move read index to the
+  // end so that these entries cannot be read anymore.
+  void ClearBefore(BlockIndex aBlockIndex) {
+    baseprofiler::detail::BaseProfilerMaybeAutoLock lock(mMutex);
+    if (!mMaybeUnderlyingBuffer) {
+      return;
+    }
+    // Don't accept a not-yet-written index. One-past-the-end is ok.
+    MOZ_ASSERT(aBlockIndex <= mNextWriteIndex);
+    if (aBlockIndex <= mFirstReadIndex) {
+      // Already cleared.
+      return;
+    }
+    if (aBlockIndex == mNextWriteIndex) {
+      // Right past the end, just clear everything.
+      ClearAllEntries();
+      return;
+    }
+    // Otherwise we need to clear a subset of entries.
+    AssertBlockIndexIsValid(aBlockIndex);
+    // Just count skipped entries.
+    Reader reader(*this);
+    BlockIterator it = reader.begin();
+    for (; it.CurrentBlockIndex() < aBlockIndex; ++it) {
+      MOZ_ASSERT(it.CurrentBlockIndex() < reader.end().CurrentBlockIndex());
+      mMaybeUnderlyingBuffer->mClearedBlockCount += 1;
+    }
+    MOZ_ASSERT(it.CurrentBlockIndex() == aBlockIndex);
+    // Move read index to given index, so there's effectively no more entries
+    // before.
+    mFirstReadIndex = aBlockIndex;
+  }
+
+#ifdef DEBUG
+  void Dump() const {
+    baseprofiler::detail::BaseProfilerMaybeAutoLock lock(mMutex);
+    if (!mMaybeUnderlyingBuffer) {
+      printf("empty BlocksRingBuffer\n");
+      return;
+    }
+    using ULL = unsigned long long;
+    printf("start=%llu (%llu) end=%llu (%llu) - ", ULL(Index(mFirstReadIndex)),
+           ULL(Index(mFirstReadIndex) &
+               (mMaybeUnderlyingBuffer->mBuffer.BufferLength().Value() - 1)),
+           ULL(Index(mNextWriteIndex)),
+           ULL(Index(mNextWriteIndex) &
+               (mMaybeUnderlyingBuffer->mBuffer.BufferLength().Value() - 1)));
+    mMaybeUnderlyingBuffer->mBuffer.Dump();
+  }
+#endif  // DEBUG
+
+ private:
+  // In DEBUG mode, assert that `aBlockIndex` is a valid index for a live block.
+  // (Not just in range, but points exactly at the start of a block.)
+  // Slow, so avoid it for internal checks; this is more to check what callers
+  // provide us.
+  void AssertBlockIndexIsValid(BlockIndex aBlockIndex) const {
+#ifdef DEBUG
+    mMutex.AssertCurrentThreadOwns();
+    MOZ_ASSERT(aBlockIndex >= mFirstReadIndex);
+    MOZ_ASSERT(aBlockIndex < mNextWriteIndex);
+    // Quick check (default), or slow check (change '1' to '0') below:
+#  if 1
+    // Quick check that this looks like a valid block start.
+    // Read the entry size at the start of the block.
+    BufferReader br =
+        mMaybeUnderlyingBuffer->mBuffer.ReaderAt(Index(aBlockIndex));
+    Length entryBytes = br.ReadULEB128<Length>();
+    MOZ_ASSERT(entryBytes > 0, "Empty entries are not allowed");
+    MOZ_ASSERT(
+        entryBytes < mMaybeUnderlyingBuffer->mBuffer.BufferLength().Value() -
+                         BufferReader::ULEB128Size(entryBytes),
+        "Entry would wrap and overwrite itself");
+    // The end of the block should be inside the live buffer range.
+    MOZ_ASSERT(Index(aBlockIndex) + BufferReader::ULEB128Size(entryBytes) +
+                   entryBytes <=
+               Index(mNextWriteIndex));
+#  else
+    // Slow check that the index is really the start of the block.
+    // This kills performances, as it reads from the first index until
+    // aBlockIndex. Only use to debug issues locally.
+    Reader reader(*this);
+    BlockIterator it = reader.begin();
+    for (; it.CurrentBlockIndex() < aBlockIndex; ++it) {
+      MOZ_ASSERT(it.CurrentBlockIndex() < reader.end().CurrentBlockIndex());
+    }
+    MOZ_ASSERT(it.CurrentBlockIndex() == aBlockIndex);
+#  endif
+#endif  // DEBUG
+  }
+
+  // In DEBUG mode, assert that `aBlockIndex` is a valid index for a live block,
+  // or is just past-the-end. (Not just in range, but points exactly at the
+  // start of a block.) Slow, so avoid it for internal checks; this is more to
+  // check what callers provide us.
+  void AssertBlockIndexIsValidOrEnd(BlockIndex aBlockIndex) const {
+#ifdef DEBUG
+    mMutex.AssertCurrentThreadOwns();
+    if (aBlockIndex == mNextWriteIndex) {
+      return;
+    }
+    AssertBlockIndexIsValid(aBlockIndex);
+#endif  // DEBUG
+  }
+
+  // Create a reader for the block starting at aBlockIndex.
+  EntryReader ReaderInBlockAt(BlockIndex aBlockIndex) const {
+    mMutex.AssertCurrentThreadOwns();
+    MOZ_ASSERT(aBlockIndex >= mFirstReadIndex);
+    MOZ_ASSERT(aBlockIndex < mNextWriteIndex);
+    return EntryReader(*this, aBlockIndex);
+  }
+
+  // Clear all entries: Move read index to the end so that these entries cannot
+  // be read anymore.
+  void ClearAllEntries() {
+    mMutex.AssertCurrentThreadOwns();
+    if (!mMaybeUnderlyingBuffer) {
+      return;
+    }
+    // Mark all entries pushed so far as cleared.
+    mMaybeUnderlyingBuffer->mClearedBlockCount =
+        mMaybeUnderlyingBuffer->mPushedBlockCount;
+    // Move read index to write index, so there's effectively no more entries
+    // that can be read. (Not setting both to 0, in case user is keeping
+    // `BlockIndex`'es to old entries.)
+    mFirstReadIndex = mNextWriteIndex;
+  }
+
+  // If there is an underlying buffer, clear all entries, and discard the
+  // buffer. This BlocksRingBuffer will now gracefully reject all API calls, and
+  // is in a state where a new underlying buffer may be set.
+  void ResetUnderlyingBuffer() {
+    mMutex.AssertCurrentThreadOwns();
+    if (!mMaybeUnderlyingBuffer) {
+      return;
+    }
+    ClearAllEntries();
+    mMaybeUnderlyingBuffer.reset();
+  }
+
+  // Used to de/serialize a BlocksRingBuffer (e.g., containing a backtrace).
+  friend struct Serializer<BlocksRingBuffer>;
+  friend struct Deserializer<BlocksRingBuffer>;
+  friend struct Serializer<UniquePtr<BlocksRingBuffer>>;
+  friend struct Deserializer<UniquePtr<BlocksRingBuffer>>;
+
+  // Mutex guarding the following members.
+  mutable baseprofiler::detail::BaseProfilerMaybeMutex mMutex;
+
+  struct UnderlyingBuffer {
+    // Create a buffer of the given length.
+    explicit UnderlyingBuffer(PowerOfTwo<Length> aLength) : mBuffer(aLength) {
+      MOZ_ASSERT(aLength.Value() > ULEB128MaxSize<Length>(),
+                 "Buffer should be able to contain more than a block size");
+    }
+
+    // Take ownership of an existing buffer.
+    UnderlyingBuffer(UniquePtr<Buffer::Byte[]> aExistingBuffer,
+                     PowerOfTwo<Length> aLength)
+        : mBuffer(std::move(aExistingBuffer), aLength) {
+      MOZ_ASSERT(aLength.Value() > ULEB128MaxSize<Length>(),
+                 "Buffer should be able to contain more than a block size");
+    }
+
+    // Use an externally-owned buffer.
+    UnderlyingBuffer(Buffer::Byte* aExternalBuffer, PowerOfTwo<Length> aLength)
+        : mBuffer(aExternalBuffer, aLength) {
+      MOZ_ASSERT(aLength.Value() > ULEB128MaxSize<Length>(),
+                 "Buffer should be able to contain more than a block size");
+    }
+
+    // Only allow move-construction.
+    UnderlyingBuffer(UnderlyingBuffer&&) = default;
+
+    // Copies and move-assignment are explictly disallowed.
+    UnderlyingBuffer(const UnderlyingBuffer&) = delete;
+    UnderlyingBuffer& operator=(const UnderlyingBuffer&) = delete;
+    UnderlyingBuffer& operator=(UnderlyingBuffer&&) = delete;
+
+    // Underlying circular byte buffer.
+    Buffer mBuffer;
+
+    // Statistics.
+    uint64_t mPushedBlockCount = 0;
+    uint64_t mClearedBlockCount = 0;
+  };
+
+  // Underlying buffer, with stats.
+  // Only valid during in-session period.
+  Maybe<UnderlyingBuffer> mMaybeUnderlyingBuffer;
+
+  // Index to the first block to be read (or cleared). Initialized to 1 because
+  // 0 is reserved for the "empty" BlockIndex value. Kept between sessions, so
+  // that stored indices from one session will be gracefully denied in future
+  // sessions.
+  BlockIndex mFirstReadIndex = BlockIndex(Index(1));
+  // Index where the next new block should be allocated. Initialized to 1
+  // because 0 is reserved for the "empty" BlockIndex value. Kept between
+  // sessions, so that stored indices from one session will be gracefully denied
+  // in future sessions.
+  BlockIndex mNextWriteIndex = BlockIndex(Index(1));
+};
+
+// ============================================================================
+// Serializer and Deserializer ready-to-use specializations.
+
+// ----------------------------------------------------------------------------
+// Trivially-copyable types (default)
+
+// The default implementation works for all trivially-copyable types (e.g.,
+// PODs).
+//
+// Usage: `aEW.WriteObject(123);`.
+//
+// Raw pointers, though trivially-copyable, are explictly forbidden when writing
+// (to avoid unexpected leaks/UAFs), instead use one of
+// `WrapBlocksRingBufferLiteralCStringPointer`,
+// `WrapBlocksRingBufferUnownedCString`, or `WrapBlocksRingBufferRawPointer` as
+// needed.
+template <typename T>
+struct BlocksRingBuffer::Serializer {
+  static_assert(std::is_trivially_copyable<T>::value,
+                "Serializer only works with trivially-copyable types by "
+                "default, use/add specialization for other types.");
+
+  static constexpr Length Bytes(const T&) { return sizeof(T); }
+
+  static void Write(EntryWriter& aEW, const T& aT) {
+    static_assert(!std::is_pointer<T>::value,
+                  "Serializer won't write raw pointers by default, use "
+                  "WrapBlocksRingBufferRawPointer or other.");
+    aEW.Write(&aT, sizeof(T));
+  }
+};
+
+// Usage: `aER.ReadObject<int>();` or `int x; aER.ReadIntoObject(x);`.
+template <typename T>
+struct BlocksRingBuffer::Deserializer {
+  static_assert(std::is_trivially_copyable<T>::value,
+                "Deserializer only works with trivially-copyable types by "
+                "default, use/add specialization for other types.");
+
+  static void ReadInto(EntryReader& aER, T& aT) { aER.Read(&aT, sizeof(T)); }
+
+  static T Read(EntryReader& aER) {
+    // Note that this creates a default `T` first, and then overwrites it with
+    // bytes from the buffer. Trivially-copyable types support this without UB.
+    T ob;
+    ReadInto(aER, ob);
+    return ob;
+  }
+};
+
+// ----------------------------------------------------------------------------
+// Strip const/volatile/reference from types.
+
+// Automatically strip `const`.
+template <typename T>
+struct BlocksRingBuffer::Serializer<const T>
+    : public BlocksRingBuffer::Serializer<T> {};
+
+template <typename T>
+struct BlocksRingBuffer::Deserializer<const T>
+    : public BlocksRingBuffer::Deserializer<T> {};
+
+// Automatically strip `volatile`.
+template <typename T>
+struct BlocksRingBuffer::Serializer<volatile T>
+    : public BlocksRingBuffer::Serializer<T> {};
+
+template <typename T>
+struct BlocksRingBuffer::Deserializer<volatile T>
+    : public BlocksRingBuffer::Deserializer<T> {};
+
+// Automatically strip `lvalue-reference`.
+template <typename T>
+struct BlocksRingBuffer::Serializer<T&>
+    : public BlocksRingBuffer::Serializer<T> {};
+
+template <typename T>
+struct BlocksRingBuffer::Deserializer<T&>
+    : public BlocksRingBuffer::Deserializer<T> {};
+
+// Automatically strip `rvalue-reference`.
+template <typename T>
+struct BlocksRingBuffer::Serializer<T&&>
+    : public BlocksRingBuffer::Serializer<T> {};
+
+template <typename T>
+struct BlocksRingBuffer::Deserializer<T&&>
+    : public BlocksRingBuffer::Deserializer<T> {};
+
+// ----------------------------------------------------------------------------
+// BlockIndex
+
+// BlockIndex, serialized as the underlying value.
+template <>
+struct BlocksRingBuffer::Serializer<BlocksRingBuffer::BlockIndex> {
+  static constexpr Length Bytes(const BlockIndex& aBlockIndex) {
+    return sizeof(BlockIndex);
+  }
+
+  static void Write(EntryWriter& aEW, const BlockIndex& aBlockIndex) {
+    aEW.Write(&aBlockIndex, sizeof(aBlockIndex));
+  }
+};
+
+template <>
+struct BlocksRingBuffer::Deserializer<BlocksRingBuffer::BlockIndex> {
+  static void ReadInto(EntryReader& aER, BlockIndex& aBlockIndex) {
+    aER.Read(&aBlockIndex, sizeof(aBlockIndex));
+  }
+
+  static BlockIndex Read(EntryReader& aER) {
+    BlockIndex blockIndex;
+    ReadInto(aER, blockIndex);
+    return blockIndex;
+  }
+};
+
+// ----------------------------------------------------------------------------
+// Literal C string pointer
+
+// Wrapper around a pointer to a literal C string.
+template <BlocksRingBuffer::Length NonTerminalCharacters>
+struct BlocksRingBufferLiteralCStringPointer {
+  const char* mCString;
+};
+
+// Wrap a pointer to a literal C string.
+template <BlocksRingBuffer::Length CharactersIncludingTerminal>
+BlocksRingBufferLiteralCStringPointer<CharactersIncludingTerminal - 1>
+WrapBlocksRingBufferLiteralCStringPointer(
+    const char (&aCString)[CharactersIncludingTerminal]) {
+  return {aCString};
+}
+
+// Literal C strings, serialized as the raw pointer because it is unique and
+// valid for the whole program lifetime.
+//
+// Usage: `aEW.WriteObject(WrapBlocksRingBufferLiteralCStringPointer("hi"));`.
+//
+// No deserializer is provided for this type, instead it must be deserialized as
+// a raw pointer: `aER.ReadObject<const char*>();`
+template <BlocksRingBuffer::Length CharactersIncludingTerminal>
+struct BlocksRingBuffer::Deserializer<
+    BlocksRingBufferLiteralCStringPointer<CharactersIncludingTerminal>> {
+  static constexpr Length Bytes(const BlocksRingBufferLiteralCStringPointer<
+                                CharactersIncludingTerminal>&) {
+    // We're only storing a pointer, its size is independent from the pointer
+    // value.
+    return sizeof(const char*);
+  }
+
+  static void Write(
+      EntryWriter& aEW,
+      const BlocksRingBufferLiteralCStringPointer<CharactersIncludingTerminal>&
+          aWrapper) {
+    // Write the pointer *value*, not the string contents.
+    aEW.Write(&aWrapper.mCString, sizeof(aWrapper.mCString));
+  }
+};
+
+// ----------------------------------------------------------------------------
+// C string contents
+
+// Wrapper around a pointer to a C string whose contents will be serialized.
+struct BlocksRingBufferUnownedCString {
+  const char* mCString;
+};
+
+// Wrap a pointer to a C string whose contents will be serialized.
+inline BlocksRingBufferUnownedCString WrapBlocksRingBufferUnownedCString(
+    const char* aCString) {
+  return {aCString};
+}
+
+// The contents of a (probably) unowned C string are serialized as the number of
+// characters (encoded as ULEB128) and all the characters in the string. The
+// terminal '\0' is omitted.
+//
+// Usage: `aEW.WriteObject(WrapBlocksRingBufferUnownedCString(str.c_str()))`.
+//
+// No deserializer is provided for this pointer type, instead it must be
+// deserialized as one of the other string types that manages its contents,
+// e.g.: `aER.ReadObject<std::string>();`
+template <>
+struct BlocksRingBuffer::Serializer<BlocksRingBufferUnownedCString> {
+  static Length Bytes(const BlocksRingBufferUnownedCString& aS) {
+    const auto len = static_cast<Length>(strlen(aS.mCString));
+    return EntryWriter::ULEB128Size(len) + len;
+  }
+
+  static void Write(EntryWriter& aEW,
+                    const BlocksRingBufferUnownedCString& aS) {
+    const auto len = static_cast<Length>(strlen(aS.mCString));
+    aEW.WriteULEB128(len);
+    aEW.Write(aS.mCString, len);
+  }
+};
+
+// ----------------------------------------------------------------------------
+// Raw pointers
+
+// Wrapper around a pointer to be serialized as the raw pointer value.
+template <typename T>
+struct BlocksRingBufferRawPointer {
+  T* mRawPointer;
+};
+
+// Wrap a pointer to be serialized as the raw pointer value.
+template <typename T>
+BlocksRingBufferRawPointer<T> WrapBlocksRingBufferRawPointer(T* aRawPointer) {
+  return {aRawPointer};
+}
+
+// Raw pointers are serialized as the raw pointer value.
+//
+// Usage: `aEW.WriteObject(WrapBlocksRingBufferRawPointer(ptr));`
+//
+// The wrapper is compulsory when writing pointers (to avoid unexpected
+// leaks/UAFs), but reading can be done straight into a raw pointer object,
+// e.g.: `aER.ReadObject<Foo*>;`.
+template <typename T>
+struct BlocksRingBuffer::Serializer<BlocksRingBufferRawPointer<T>> {
+  template <typename U>
+  static constexpr Length Bytes(const U&) {
+    return sizeof(T*);
+  }
+
+  static void Write(EntryWriter& aEW,
+                    const BlocksRingBufferRawPointer<T>& aWrapper) {
+    aEW.Write(&aWrapper.mRawPointer, sizeof(aWrapper.mRawPointer));
+  }
+};
+
+// Usage: `aER.ReadObject<Foo*>;` or `Foo* p; aER.ReadIntoObject(p);`, no
+// wrapper necessary.
+template <typename T>
+struct BlocksRingBuffer::Deserializer<BlocksRingBufferRawPointer<T>> {
+  static void ReadInto(EntryReader& aER, T*& aPtr) {
+    aER.Read(&aPtr, sizeof(aPtr));
+  }
+
+  static T* Read(EntryReader& aER) {
+    T* ptr;
+    ReadInto(aER, ptr);
+    return ptr;
+  }
+};
+
+// ----------------------------------------------------------------------------
+// std::string contents
+
+// std::string contents are serialized as the number of characters (encoded as
+// ULEB128) and all the characters in the string. The terminal '\0' is omitted.
+//
+// Usage: `std::string s = ...; aEW.WriteObject(s);`
+template <>
+struct BlocksRingBuffer::Serializer<std::string> {
+  static Length Bytes(const std::string& aS) {
+    const auto len = aS.length();
+    return EntryWriter::ULEB128Size(len) + static_cast<Length>(len);
+  }
+
+  static void Write(EntryWriter& aEW, const std::string& aS) {
+    const auto len = aS.length();
+    aEW.WriteULEB128(len);
+    aEW.Write(aS.c_str(), len);
+  }
+};
+
+// Usage: `std::string s = aEW.ReadObject<std::string>(s);` or
+// `std::string s; aER.ReadIntoObject(s);`
+template <>
+struct BlocksRingBuffer::Deserializer<std::string> {
+  static void ReadInto(EntryReader& aER, std::string& aS) {
+    const auto len = aER.ReadULEB128<std::string::size_type>();
+    // Assign to `aS` by using iterators.
+    // (`aER+0` so we get the same iterator type as `aER+len`.)
+    aS.assign(aER + 0, aER + len);
+    aER += len;
+  }
+
+  static std::string Read(EntryReader& aER) {
+    const auto len = aER.ReadULEB128<std::string::size_type>();
+    // Construct a string by using iterators.
+    // (`aER+0` so we get the same iterator type as `aER+len`.)
+    std::string s(aER + 0, aER + len);
+    aER += len;
+    return s;
+  }
+};
+
+// ----------------------------------------------------------------------------
+// mozilla::UniqueFreePtr<CHAR>
+
+// UniqueFreePtr<CHAR>, which points at a string allocated with `malloc`
+// (typically generated by `strdup()`), is serialized as the number of
+// *bytes* (encoded as ULEB128) and all the characters in the string. The
+// null terminator is omitted.
+// `CHAR` can be any type that has a specialization for
+// `std::char_traits<CHAR>::length(const CHAR*)`.
+//
+// Note: A nullptr pointer will be serialized like an empty string, so when
+// deserializing it will result in an allocated buffer only containing a
+// single null terminator.
+template <typename CHAR>
+struct BlocksRingBuffer::Serializer<UniqueFreePtr<CHAR>> {
+  static Length Bytes(const UniqueFreePtr<CHAR>& aS) {
+    if (!aS) {
+      // Null pointer, store it as if it was an empty string (so: 0 bytes).
+      return EntryWriter::ULEB128Size(0u);
+    }
+    // Note that we store the size in *bytes*, not in number of characters.
+    const auto bytes = static_cast<Length>(
+        std::char_traits<CHAR>::length(aS.get()) * sizeof(CHAR));
+    return EntryWriter::ULEB128Size(bytes) + bytes;
+  }
+
+  static void Write(EntryWriter& aEW, const UniqueFreePtr<CHAR>& aS) {
+    if (!aS) {
+      // Null pointer, store it as if it was an empty string (so we write a
+      // length of 0 bytes).
+      aEW.WriteULEB128(0u);
+      return;
+    }
+    // Note that we store the size in *bytes*, not in number of characters.
+    const auto bytes = static_cast<Length>(
+        std::char_traits<CHAR>::length(aS.get()) * sizeof(CHAR));
+    aEW.WriteULEB128(bytes);
+    aEW.Write(aS.get(), bytes);
+  }
+};
+
+template <typename CHAR>
+struct BlocksRingBuffer::Deserializer<UniqueFreePtr<CHAR>> {
+  static void ReadInto(EntryReader& aER, UniqueFreePtr<CHAR>& aS) {
+    aS = Read(aER);
+  }
+
+  static UniqueFreePtr<CHAR> Read(EntryReader& aER) {
+    // Read the number of *bytes* that follow.
+    const auto bytes = aER.ReadULEB128<Length>();
+    // We need a buffer of the non-const character type.
+    using NC_CHAR = std::remove_const_t<CHAR>;
+    // We allocate the required number of bytes, plus one extra character for
+    // the null terminator.
+    NC_CHAR* buffer = static_cast<NC_CHAR*>(malloc(bytes + sizeof(NC_CHAR)));
+    // Copy the characters into the buffer.
+    aER.Read(buffer, bytes);
+    // And append a null terminator.
+    buffer[bytes / sizeof(NC_CHAR)] = NC_CHAR(0);
+    return UniqueFreePtr<CHAR>(buffer);
+  }
+};
+
+// ----------------------------------------------------------------------------
+// std::tuple
+
+// std::tuple is serialized as a sequence of each recursively-serialized item.
+//
+// This is equivalent to manually serializing each item, so reading/writing
+// tuples is equivalent to reading/writing their elements in order, e.g.:
+// ```
+// std::tuple<int, std::string> is = ...;
+// aEW.WriteObject(is); // Write the tuple, equivalent to:
+// aEW.WriteObject(/* int */ std::get<0>(is), /* string */ std::get<1>(is));
+// ...
+// // Reading back can be done directly into a tuple:
+// auto is = aER.ReadObject<std::tuple<int, std::string>>();
+// // Or each item could be read separately:
+// auto i = aER.ReadObject<int>(); auto s = aER.ReadObject<std::string>();
+// ```
+template <typename... Ts>
+struct BlocksRingBuffer::Serializer<std::tuple<Ts...>> {
+ private:
+  template <size_t... Is>
+  static Length TupleBytes(const std::tuple<Ts...>& aTuple,
+                           std::index_sequence<Is...>) {
+    Length bytes = 0;
+    // This is pre-C++17 fold trick, using `initializer_list` to unpack the `Is`
+    // variadic pack, and the comma operator to:
+    // (work on each tuple item, generate an int for the list). Note that the
+    // `initializer_list` is unused; the compiler will nicely optimize it away.
+    // `std::index_sequence` is just a way to have `Is` be a variadic pack
+    // containing numbers between 0 and (tuple size - 1).
+    // The compiled end result is like doing:
+    //   bytes += SumBytes(get<0>(aTuple));
+    //   bytes += SumBytes(get<1>(aTuple));
+    //   ...
+    //   bytes += SumBytes(get<sizeof...(aTuple) - 1>(aTuple));
+    // See https://articles.emptycrate.com/2016/05/14/folds_in_cpp11_ish.html
+    // TODO: Replace with C++17 fold.
+    Unused << std::initializer_list<int>{
+        (bytes += SumBytes(std::get<Is>(aTuple)), 0)...};
+    return bytes;
+  }
+
+  template <size_t... Is>
+  static void TupleWrite(EntryWriter& aEW, const std::tuple<Ts...>& aTuple,
+                         std::index_sequence<Is...>) {
+    // TODO: Replace with C++17 fold.
+    Unused << std::initializer_list<int>{
+        (aEW.WriteObject(std::get<Is>(aTuple)), 0)...};
+  }
+
+ public:
+  static Length Bytes(const std::tuple<Ts...>& aTuple) {
+    // Generate a 0..N-1 index pack, we'll add the sizes of each item.
+    return TupleBytes(aTuple, std::index_sequence_for<Ts...>());
+  }
+
+  static void Write(EntryWriter& aEW, const std::tuple<Ts...>& aTuple) {
+    // Generate a 0..N-1 index pack, we'll write each item.
+    TupleWrite(aEW, aTuple, std::index_sequence_for<Ts...>());
+  }
+};
+
+template <typename... Ts>
+struct BlocksRingBuffer::Deserializer<std::tuple<Ts...>> {
+  static void ReadInto(EntryReader& aER, std::tuple<Ts...>& aTuple) {
+    aER.Read(&aTuple, Bytes(aTuple));
+  }
+
+  static std::tuple<Ts...> Read(EntryReader& aER) {
+    // Note that this creates default `Ts` first, and then overwrites them.
+    std::tuple<Ts...> ob;
+    ReadInto(aER, ob);
+    return ob;
+  }
+};
+
+// ----------------------------------------------------------------------------
+// mozilla::Tuple
+
+// Tuple is serialized as a sequence of each recursively-serialized
+// item.
+//
+// This is equivalent to manually serializing each item, so reading/writing
+// tuples is equivalent to reading/writing their elements in order, e.g.:
+// ```
+// Tuple<int, std::string> is = ...;
+// aEW.WriteObject(is); // Write the Tuple, equivalent to:
+// aEW.WriteObject(/* int */ std::get<0>(is), /* string */ std::get<1>(is));
+// ...
+// // Reading back can be done directly into a Tuple:
+// auto is = aER.ReadObject<Tuple<int, std::string>>();
+// // Or each item could be read separately:
+// auto i = aER.ReadObject<int>(); auto s = aER.ReadObject<std::string>();
+// ```
+template <typename... Ts>
+struct BlocksRingBuffer::Serializer<Tuple<Ts...>> {
+ private:
+  template <size_t... Is>
+  static Length TupleBytes(const Tuple<Ts...>& aTuple,
+                           std::index_sequence<Is...>) {
+    Length bytes = 0;
+    // TODO: Replace with C++17 fold.
+    Unused << std::initializer_list<int>{
+        (bytes += SumBytes(Get<Is>(aTuple)), 0)...};
+    return bytes;
+  }
+
+  template <size_t... Is>
+  static void TupleWrite(EntryWriter& aEW, const Tuple<Ts...>& aTuple,
+                         std::index_sequence<Is...>) {
+    // TODO: Replace with C++17 fold.
+    Unused << std::initializer_list<int>{
+        (aEW.WriteObject(Get<Is>(aTuple)), 0)...};
+  }
+
+ public:
+  static Length Bytes(const Tuple<Ts...>& aTuple) {
+    // Generate a 0..N-1 index pack, we'll add the sizes of each item.
+    return TupleBytes(aTuple, std::index_sequence_for<Ts...>());
+  }
+
+  static void Write(EntryWriter& aEW, const Tuple<Ts...>& aTuple) {
+    // Generate a 0..N-1 index pack, we'll write each item.
+    TupleWrite(aEW, aTuple, std::index_sequence_for<Ts...>());
+  }
+};
+
+template <typename... Ts>
+struct BlocksRingBuffer::Deserializer<Tuple<Ts...>> {
+  static void ReadInto(EntryReader& aER, Tuple<Ts...>& aTuple) {
+    aER.Read(&aTuple, Bytes(aTuple));
+  }
+
+  static Tuple<Ts...> Read(EntryReader& aER) {
+    // Note that this creates default `Ts` first, and then overwrites them.
+    Tuple<Ts...> ob;
+    ReadInto(aER, ob);
+    return ob;
+  }
+};
+
+// ----------------------------------------------------------------------------
+// mozilla::Span
+
+// Span. All elements are serialized in sequence.
+// The caller is assumed to know the number of elements (they may manually
+// write&read it before the span if needed).
+// Similar to tuples, reading/writing spans is equivalent to reading/writing
+// their elements in order.
+template <class T, size_t N>
+struct BlocksRingBuffer::Serializer<Span<T, N>> {
+  static Length Bytes(const Span<T, N>& aSpan) {
+    Length bytes = 0;
+    for (const T& element : aSpan) {
+      bytes += SumBytes(element);
+    }
+    return bytes;
+  }
+
+  static void Write(EntryWriter& aEW, const Span<T, N>& aSpan) {
+    for (const T& element : aSpan) {
+      aEW.WriteObject(element);
+    }
+  }
+};
+
+template <class T, size_t N>
+struct BlocksRingBuffer::Deserializer<Span<T, N>> {
+  // Read elements back into span pointing at a pre-allocated buffer.
+  static void ReadInto(EntryReader& aER, Span<T, N>& aSpan) {
+    for (T& element : aSpan) {
+      aER.ReadIntoObject(element);
+    }
+  }
+
+  // A Span does not own its data, this would probably leak so we forbid this.
+  static Span<T, N> Read(EntryReader& aER) = delete;
+};
+
+// ----------------------------------------------------------------------------
+// mozilla::Maybe
+
+// Maybe<T> is serialized as one byte containing either 'm' (Nothing),
+// or 'M' followed by the recursively-serialized `T` object.
+template <typename T>
+struct BlocksRingBuffer::Serializer<Maybe<T>> {
+  static Length Bytes(const Maybe<T>& aMaybe) {
+    // 1 byte to store nothing/something flag, then object size if present.
+    return aMaybe.isNothing() ? 1 : (1 + SumBytes(aMaybe.ref()));
+  }
+
+  static void Write(EntryWriter& aEW, const Maybe<T>& aMaybe) {
+    // 'm'/'M' is just an arbitrary 1-byte value to distinguish states.
+    if (aMaybe.isNothing()) {
+      aEW.WriteObject<char>('m');
+    } else {
+      aEW.WriteObject<char>('M');
+      // Use the Serializer for the contained type.
+      aEW.WriteObject(aMaybe.ref());
+    }
+  }
+};
+
+template <typename T>
+struct BlocksRingBuffer::Deserializer<Maybe<T>> {
+  static void ReadInto(EntryReader& aER, Maybe<T>& aMaybe) {
+    char c = aER.ReadObject<char>();
+    if (c == 'm') {
+      aMaybe.reset();
+    } else {
+      MOZ_ASSERT(c == 'M');
+      // If aMaybe is empty, create a default `T` first, to be overwritten.
+      // Otherwise we'll just overwrite whatever was already there.
+      if (aMaybe.isNothing()) {
+        aMaybe.emplace();
+      }
+      // Use the Deserializer for the contained type.
+      aER.ReadIntoObject(aMaybe.ref());
+    }
+  }
+
+  static Maybe<T> Read(EntryReader& aER) {
+    Maybe<T> maybe;
+    char c = aER.ReadObject<char>();
+    MOZ_ASSERT(c == 'M' || c == 'm');
+    if (c == 'M') {
+      // Note that this creates a default `T` inside the Maybe first, and then
+      // overwrites it.
+      maybe = Some(T{});
+      // Use the Deserializer for the contained type.
+      aER.ReadIntoObject(maybe.ref());
+    }
+    return maybe;
+  }
+};
+
+// ----------------------------------------------------------------------------
+// mozilla::Variant
+
+// Variant is serialized as the tag (0-based index of the stored type, encoded
+// as ULEB128), and the recursively-serialized object.
+template <typename... Ts>
+struct BlocksRingBuffer::Serializer<Variant<Ts...>> {
+ private:
+  // Called from the fold expression in `VariantBytes()`, only the selected
+  // variant will write into `aOutBytes`.
+  template <size_t I>
+  static void VariantIBytes(const Variant<Ts...>& aVariantTs,
+                            Length& aOutBytes) {
+    if (aVariantTs.template is<I>()) {
+      aOutBytes =
+          EntryReader::ULEB128Size(I) + SumBytes(aVariantTs.template as<I>());
+    }
+  }
+
+  // Go through all variant tags, and let the selected one write the correct
+  // number of bytes.
+  template <size_t... Is>
+  static Length VariantBytes(const Variant<Ts...>& aVariantTs,
+                             std::index_sequence<Is...>) {
+    Length bytes = 0;
+    // TODO: Replace with C++17 fold.
+    Unused << std::initializer_list<int>{
+        (VariantIBytes<Is>(aVariantTs, bytes), 0)...};
+    MOZ_ASSERT(bytes != 0);
+    return bytes;
+  }
+
+  // Called from the fold expression in `VariantWrite()`, only the selected
+  // variant will serialize the tag and object.
+  template <size_t I>
+  static void VariantIWrite(EntryWriter& aEW,
+                            const Variant<Ts...>& aVariantTs) {
+    if (aVariantTs.template is<I>()) {
+      aEW.WriteULEB128(I);
+      // Use the Serializer for the contained type.
+      aEW.WriteObject(aVariantTs.template as<I>());
+    }
+  }
+
+  // Go through all variant tags, and let the selected one serialize the correct
+  // tag and object.
+  template <size_t... Is>
+  static void VariantWrite(EntryWriter& aEW, const Variant<Ts...>& aVariantTs,
+                           std::index_sequence<Is...>) {
+    // TODO: Replace with C++17 fold.
+    Unused << std::initializer_list<int>{
+        (VariantIWrite<Is>(aEW, aVariantTs), 0)...};
+  }
+
+ public:
+  static Length Bytes(const Variant<Ts...>& aVariantTs) {
+    // Generate a 0..N-1 index pack, the selected variant will return its size.
+    return VariantBytes(aVariantTs, std::index_sequence_for<Ts...>());
+  }
+
+  static void Write(EntryWriter& aEW, const Variant<Ts...>& aVariantTs) {
+    // Generate a 0..N-1 index pack, the selected variant will serialize itself.
+    VariantWrite(aEW, aVariantTs, std::index_sequence_for<Ts...>());
+  }
+};
+
+template <typename... Ts>
+struct BlocksRingBuffer::Deserializer<Variant<Ts...>> {
+ private:
+  // Called from the fold expression in `VariantReadInto()`, only the selected
+  // variant will deserialize the object.
+  template <size_t I>
+  static void VariantIReadInto(EntryReader& aER, Variant<Ts...>& aVariantTs,
+                               unsigned aTag) {
+    if (I == aTag) {
+      // Ensure the variant contains the target type. Note that this may create
+      // a default object.
+      if (!aVariantTs.template is<I>()) {
+        aVariantTs = Variant<Ts...>(VariantIndex<I>{});
+      }
+      aER.ReadIntoObject(aVariantTs.template as<I>());
+    }
+  }
+
+  template <size_t... Is>
+  static void VariantReadInto(EntryReader& aER, Variant<Ts...>& aVariantTs,
+                              std::index_sequence<Is...>) {
+    unsigned tag = aER.ReadULEB128<unsigned>();
+    // TODO: Replace with C++17 fold.
+    Unused << std::initializer_list<int>{
+        (VariantIReadInto<Is>(aER, aVariantTs, tag), 0)...};
+  }
+
+ public:
+  static void ReadInto(EntryReader& aER, Variant<Ts...>& aVariantTs) {
+    // Generate a 0..N-1 index pack, the selected variant will deserialize
+    // itself.
+    VariantReadInto(aER, aVariantTs, std::index_sequence_for<Ts...>());
+  }
+
+  static Variant<Ts...> Read(EntryReader& aER) {
+    // Note that this creates a default `Variant` of the first type, and then
+    // overwrites it. Consider using `ReadInto` for more control if needed.
+    Variant<Ts...> variant(VariantIndex<0>{});
+    ReadInto(aER, variant);
+    return variant;
+  }
+};
+
+// ----------------------------------------------------------------------------
+// BlocksRingBuffer
+
+// A BlocksRingBuffer can hide another one!
+// This will be used to store marker backtraces; They can be read back into a
+// UniquePtr<BlocksRingBuffer>.
+// Format: len (ULEB128) | start | end | buffer (len bytes) | pushed | cleared
+// len==0 marks an out-of-session buffer, or empty buffer.
+template <>
+struct BlocksRingBuffer::Serializer<BlocksRingBuffer> {
+  static Length Bytes(const BlocksRingBuffer& aBuffer) {
+    baseprofiler::detail::BaseProfilerMaybeAutoLock lock(aBuffer.mMutex);
+    if (aBuffer.mMaybeUnderlyingBuffer.isNothing()) {
+      // Out-of-session, we only need 1 byte to store a length of 0.
+      return ULEB128Size<Length>(0);
+    }
+    const auto start = Index(aBuffer.mFirstReadIndex);
+    const auto end = Index(aBuffer.mNextWriteIndex);
+    const auto len = end - start;
+    if (len == 0) {
+      // In-session but empty, also store a length of 0.
+      return ULEB128Size<Length>(0);
+    }
+    return ULEB128Size(len) + sizeof(start) + sizeof(end) + len +
+           sizeof(aBuffer.mMaybeUnderlyingBuffer->mPushedBlockCount) +
+           sizeof(aBuffer.mMaybeUnderlyingBuffer->mClearedBlockCount);
+  }
+
+  static void Write(EntryWriter& aEW, const BlocksRingBuffer& aBuffer) {
+    baseprofiler::detail::BaseProfilerMaybeAutoLock lock(aBuffer.mMutex);
+    if (aBuffer.mMaybeUnderlyingBuffer.isNothing()) {
+      // Out-of-session, only store a length of 0.
+      aEW.WriteULEB128<Length>(0);
+      return;
+    }
+    const auto start = Index(aBuffer.mFirstReadIndex);
+    const auto end = Index(aBuffer.mNextWriteIndex);
+    MOZ_ASSERT(end - start <= std::numeric_limits<Length>::max());
+    const auto len = static_cast<Length>(end - start);
+    if (len == 0) {
+      // In-session but empty, only store a length of 0.
+      aEW.WriteULEB128<Length>(0);
+      return;
+    }
+    // In-session.
+    // Store buffer length, start and end indices.
+    aEW.WriteULEB128<Length>(len);
+    aEW.WriteObject(start);
+    aEW.WriteObject(end);
+    // Write all the bytes.
+    aBuffer.mMaybeUnderlyingBuffer->mBuffer.ReaderAt(start).ReadInto(aEW, len);
+    // And write stats.
+    aEW.WriteObject(aBuffer.mMaybeUnderlyingBuffer->mPushedBlockCount);
+    aEW.WriteObject(aBuffer.mMaybeUnderlyingBuffer->mClearedBlockCount);
+  }
+};
+
+// A serialized BlocksRingBuffer can be read into an empty buffer (either
+// out-of-session, or in-session with enough room).
+template <>
+struct BlocksRingBuffer::Deserializer<BlocksRingBuffer> {
+  static void ReadInto(EntryReader& aER, BlocksRingBuffer& aBuffer) {
+    // Expect an empty buffer, as we're going to overwrite it.
+    MOZ_ASSERT(aBuffer.GetState().mRangeStart == aBuffer.GetState().mRangeEnd);
+    // Read the stored buffer length.
+    const auto len = aER.ReadULEB128<BlocksRingBuffer::Length>();
+    if (len == 0) {
+      // 0-length means an "uninteresting" buffer, just return now.
+      return;
+    }
+    // We have a non-empty buffer to read.
+    if (aBuffer.BufferLength().isSome()) {
+      // Output buffer is in-session (i.e., it already has a memory buffer
+      // attached). Make sure the caller allocated enough space.
+      MOZ_RELEASE_ASSERT(aBuffer.BufferLength()->Value() >= len);
+    } else {
+      // Output buffer is out-of-session, attach a new memory buffer.
+      aBuffer.Set(PowerOfTwo<BlocksRingBuffer::Length>(len));
+      MOZ_ASSERT(aBuffer.BufferLength()->Value() >= len);
+    }
+    // Read start and end indices.
+    const auto start = aER.ReadObject<BlocksRingBuffer::Index>();
+    aBuffer.mFirstReadIndex = BlocksRingBuffer::BlockIndex(start);
+    const auto end = aER.ReadObject<BlocksRingBuffer::Index>();
+    aBuffer.mNextWriteIndex = BlocksRingBuffer::BlockIndex(end);
+    MOZ_ASSERT(end - start == len);
+    // Copy bytes into the buffer.
+    auto writer = aBuffer.mMaybeUnderlyingBuffer->mBuffer.WriterAt(start);
+    aER.ReadInto(writer, len);
+    MOZ_ASSERT(writer.CurrentIndex() == end);
+    // Finally copy stats.
+    aBuffer.mMaybeUnderlyingBuffer->mPushedBlockCount = aER.ReadObject<decltype(
+        aBuffer.mMaybeUnderlyingBuffer->mPushedBlockCount)>();
+    aBuffer.mMaybeUnderlyingBuffer->mClearedBlockCount =
+        aER.ReadObject<decltype(
+            aBuffer.mMaybeUnderlyingBuffer->mClearedBlockCount)>();
+  }
+
+  // We cannot output a BlocksRingBuffer object (not copyable), use `ReadInto()`
+  // or `aER.ReadObject<UniquePtr<BlocksRinbBuffer>>()` instead.
+  static BlocksRingBuffer Read(BlocksRingBuffer::EntryReader& aER) = delete;
+};
+
+// A BlocksRingBuffer is usually refererenced through a UniquePtr, for
+// convenience we support (de)serializing that UniquePtr directly.
+// This is compatible with the non-UniquePtr serialization above, with a null
+// pointer being treated like an out-of-session or empty buffer; and any of
+// these would be deserialized into a null pointer.
+template <>
+struct BlocksRingBuffer::Serializer<UniquePtr<BlocksRingBuffer>> {
+  static Length Bytes(const UniquePtr<BlocksRingBuffer>& aBufferUPtr) {
+    if (!aBufferUPtr) {
+      // Null pointer, treat it like an empty buffer, i.e., write length of 0.
+      return ULEB128Size<Length>(0);
+    }
+    // Otherwise write the pointed-at BlocksRingBuffer (which could be
+    // out-of-session or empty.)
+    return SumBytes(*aBufferUPtr);
+  }
+
+  static void Write(EntryWriter& aEW,
+                    const UniquePtr<BlocksRingBuffer>& aBufferUPtr) {
+    if (!aBufferUPtr) {
+      // Null pointer, treat it like an empty buffer, i.e., write length of 0.
+      aEW.WriteULEB128<Length>(0);
+      return;
+    }
+    // Otherwise write the pointed-at BlocksRingBuffer (which could be
+    // out-of-session or empty.)
+    aEW.WriteObject(*aBufferUPtr);
+  }
+};
+
+template <>
+struct BlocksRingBuffer::Deserializer<UniquePtr<BlocksRingBuffer>> {
+  static void ReadInto(EntryReader& aER, UniquePtr<BlocksRingBuffer>& aBuffer) {
+    aBuffer = Read(aER);
+  }
+
+  static UniquePtr<BlocksRingBuffer> Read(BlocksRingBuffer::EntryReader& aER) {
+    UniquePtr<BlocksRingBuffer> bufferUPtr;
+    // Read the stored buffer length.
+    const auto len = aER.ReadULEB128<BlocksRingBuffer::Length>();
+    if (len == 0) {
+      // 0-length means an "uninteresting" buffer, just return nullptr.
+      return bufferUPtr;
+    }
+    // We have a non-empty buffer.
+    // allocate an empty BlocksRingBuffer without mutex.
+    bufferUPtr = MakeUnique<BlocksRingBuffer>(
+        BlocksRingBuffer::ThreadSafety::WithoutMutex);
+    // Rewind the reader before the length and deserialize the contents, using
+    // the non-UniquePtr Deserializer.
+    aER -= ULEB128Size(len);
+    aER.ReadIntoObject(*bufferUPtr);
+    return bufferUPtr;
+  }
+};
+
+}  // namespace mozilla
+
+#endif  // BlocksRingBuffer_h
diff --git a/mozglue/baseprofiler/public/ModuloBuffer.h b/mozglue/baseprofiler/public/ModuloBuffer.h
new file mode 100644
index 0000000000..4fef6d5247
--- /dev/null
+++ b/mozglue/baseprofiler/public/ModuloBuffer.h
@@ -0,0 +1,530 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef ModuloBuffer_h
+#define ModuloBuffer_h
+
+#include "mozilla/leb128iterator.h"
+#include "mozilla/MemoryReporting.h"
+#include "mozilla/NotNull.h"
+#include "mozilla/PowerOfTwo.h"
+#include "mozilla/UniquePtr.h"
+
+#include <iterator>
+#include <limits>
+#include <type_traits>
+
+namespace mozilla {
+
+// The ModuloBuffer class is a circular buffer that holds raw byte values, with
+// data-read/write helpers.
+//
+// OffsetT: Type of the internal offset into the buffer of bytes, it should be
+// large enough to access all bytes of the buffer. It will also be used as
+// Length (in bytes) of the buffer and of any subset. Default uint32_t
+// IndexT: Type of the external index, it should be large enough that overflows
+// should not happen during the lifetime of the ModuloBuffer.
+//
+// The basic usage is to create an iterator-like object with `ReaderAt(Index)`
+// or `WriterAt(Index)`, and use it to read/write data blobs. Iterators
+// automatically manage the wrap-around (through "Modulo", which is effectively
+// an AND-masking with the PowerOfTwo buffer size.)
+//
+// There is zero safety: No thread safety, no checks that iterators may be
+// overwriting data that's still to be read, etc. It's up to the caller to add
+// adequate checks.
+// The intended use is as an underlying buffer for a safer container.
+template <typename OffsetT = uint32_t, typename IndexT = uint64_t>
+class ModuloBuffer {
+ public:
+  using Byte = uint8_t;
+  static_assert(sizeof(Byte) == 1, "ModuloBuffer::Byte must be 1 byte");
+  using Offset = OffsetT;
+  static_assert(!std::numeric_limits<Offset>::is_signed,
+                "ModuloBuffer::Offset must be an unsigned integral type");
+  using Length = Offset;
+  using Index = IndexT;
+  static_assert(!std::numeric_limits<Index>::is_signed,
+                "ModuloBuffer::Index must be an unsigned integral type");
+  static_assert(sizeof(Index) >= sizeof(Offset),
+                "ModuloBuffer::Index size must >= Offset");
+
+  // Create a buffer of the given length.
+  explicit ModuloBuffer(PowerOfTwo<Length> aLength)
+      : mMask(aLength.Mask()),
+        mBuffer(WrapNotNull(new Byte[aLength.Value()])),
+        mBufferDeleter([](Byte* aBuffer) { delete[] aBuffer; }) {}
+
+  // Take ownership of an existing buffer. Existing contents is ignored.
+  // Done by extracting the raw pointer from UniquePtr<Byte[]>, and adding
+  // an equivalent `delete[]` in `mBufferDeleter`.
+  ModuloBuffer(UniquePtr<Byte[]> aExistingBuffer, PowerOfTwo<Length> aLength)
+      : mMask(aLength.Mask()),
+        mBuffer(WrapNotNull(aExistingBuffer.release())),
+        mBufferDeleter([](Byte* aBuffer) { delete[] aBuffer; }) {}
+
+  // Use an externally-owned buffer. Existing contents is ignored.
+  ModuloBuffer(Byte* aExternalBuffer, PowerOfTwo<Length> aLength)
+      : mMask(aLength.Mask()), mBuffer(WrapNotNull(aExternalBuffer)) {}
+
+  // Disallow copying, as we may uniquely own the resource.
+  ModuloBuffer(const ModuloBuffer& aOther) = delete;
+  ModuloBuffer& operator=(const ModuloBuffer& aOther) = delete;
+
+  // Allow move-construction. Stealing ownership if the original had it.
+  // This effectively prevents copy construction, and all assignments; needed so
+  // that a ModuloBuffer may be initialized from a separate construction.
+  // The moved-from ModuloBuffer still points at the resource but doesn't own
+  // it, so it won't try to free it; but accesses are not guaranteed, so it
+  // should not be used anymore.
+  ModuloBuffer(ModuloBuffer&& aOther)
+      : mMask(std::move(aOther.mMask)),
+        mBuffer(std::move(aOther.mBuffer)),
+        mBufferDeleter(std::move(aOther.mBufferDeleter)) {
+    // The above move leaves `aOther.mBufferDeleter` in a valid state but with
+    // an unspecified value, so it could theoretically still contain the
+    // original function, which would be bad because we don't want aOther to
+    // delete the resource that `this` now owns.
+    if (aOther.mBufferDeleter) {
+      // `aOther` still had a non-empty deleter, reset it.
+      aOther.mBufferDeleter = nullptr;
+    }
+  }
+
+  // Disallow assignment, as we have some `const` members.
+  ModuloBuffer& operator=(ModuloBuffer&& aOther) = delete;
+
+  // Destructor, deletes the resource if we uniquely own it.
+  ~ModuloBuffer() {
+    if (mBufferDeleter) {
+      mBufferDeleter(mBuffer);
+    }
+  }
+
+  PowerOfTwo<Length> BufferLength() const {
+    return PowerOfTwo<Length>(mMask.MaskValue() + 1);
+  }
+
+  // Size of external resources.
+  // Note: `mBufferDeleter`'s potential external data (for its captures) is not
+  // included, as it's hidden in the `std::function` implementation.
+  size_t SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const {
+    if (!mBufferDeleter) {
+      // If we don't have a buffer deleter, assume we don't own the data, so
+      // it's probably on the stack, or should be reported by its owner.
+      return 0;
+    }
+    return aMallocSizeOf(mBuffer);
+  }
+
+  size_t SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const {
+    return aMallocSizeOf(this) + SizeOfExcludingThis(aMallocSizeOf);
+  }
+
+  // All ModuloBuffer operations should be done through this iterator, which has
+  // an effectively infinite range. The underlying wrapping-around is hidden.
+  // Use `ReaderAt(Index)` or `WriterAt(Index)` to create it.
+  //
+  // `const Iterator<...>` means the iterator itself cannot change, i.e., it
+  // cannot move, and only its const methods are available. Note that these
+  // const methods may still be used to modify the buffer contents (e.g.:
+  // `operator*()`, `Poke()`).
+  //
+  // `Iterator</*IsBufferConst=*/true>` means the buffer contents cannot be
+  // modified, i.e., write operations are forbidden, but the iterator may still
+  // move if non-const itself.
+  template <bool IsBufferConst>
+  class Iterator {
+    // Alias to const- or mutable-`ModuloBuffer` depending on `IsBufferConst`.
+    using ConstOrMutableBuffer =
+        std::conditional_t<IsBufferConst, const ModuloBuffer, ModuloBuffer>;
+
+    // Implementation note about the strange enable-if's below:
+    //   `template <bool NotIBC = !IsBufferConst> enable_if_t<NotIBC>`
+    // which intuitively could be simplified to:
+    //   `enable_if_t<!IsBufferConst>`
+    // The former extra-templated syntax is in fact necessary to delay
+    // instantiation of these functions until they are actually needed.
+    //
+    // If we were just doing `enable_if_t<!IsBufferConst>`, this would only
+    // depend on the *class* (`ModuloBuffer<...>::Iterator`), which gets
+    // instantiated when a `ModuloBuffer` is created with some template
+    // arguments; at that point, all non-templated methods get instantiated, so
+    // there's no "SFINAE" happening, and `enable_if_t<...>` is actually doing
+    // `typename enable_if<...>::type` on the spot, but there is no `type` if
+    // `IsBufferConst` is true, so it just fails right away. E.g.:
+    // error: no type named 'type' in 'std::enable_if<false, void>';
+    //        'enable_if' cannot be used to disable this declaration
+    // note: in instantiation of template type alias 'enable_if_t'
+    // > std::enable_if_t<!IsBufferConst> WriteObject(const T& aObject) {
+    //       in instantiation of template class
+    //       'mozilla::ModuloBuffer<...>::Iterator<true>'
+    // > auto it = mb.ReaderAt(1);
+    //
+    // By adding another template level `template <bool NotIsBufferConst =
+    // !IsBufferConst>`, the instantiation is delayed until the function is
+    // actually invoked somewhere, e.g. `it.Poke(...);`.
+    // So at that invocation point, the compiler looks for a "Poke" name in it,
+    // and considers potential template instantiations that could work. The
+    // `enable_if_t` is *now* attempted, with `NotIsBufferConst` taking its
+    // value from `!IsBufferConst`:
+    // - If `IsBufferConst` is false, `NotIsBufferConst` is true,
+    // `enable_if<NotIsBufferConst>` does define a `type` (`void` by default),
+    // so `enable_if_t` happily becomes `void`, the function exists and may be
+    // called.
+    // - Otherwise if `IsBufferConst` is true, `NotIsBufferConst` is false,
+    // `enable_if<NotIsBufferConst>` does *not* define a `type`, therefore
+    // `enable_if_t` produces an error because there is no `type`. Now "SFINAE"
+    // happens: This "Substitution Failure Is Not An Error" (by itself)... But
+    // then, there are no other functions named "Poke" as requested in the
+    // `it.Poke(...);` call, so we are now getting an error (can't find
+    // function), as expected because `it` had `IsBufferConst`==true. (But at
+    // least the compiler waited until this invocation attempt before outputting
+    // an error.)
+    //
+    // C++ is fun!
+
+   public:
+    // These definitions are expected by std functions, to recognize this as an
+    // iterator. See https://en.cppreference.com/w/cpp/iterator/iterator_traits
+    using difference_type = Index;
+    using value_type = Byte;
+    using pointer = std::conditional_t<IsBufferConst, const Byte*, Byte*>;
+    using reference = std::conditional_t<IsBufferConst, const Byte&, Byte&>;
+    using iterator_category = std::random_access_iterator_tag;
+
+    // Can always copy/assign from the same kind of iterator.
+    Iterator(const Iterator& aRhs) = default;
+    Iterator& operator=(const Iterator& aRhs) = default;
+
+    // Can implicitly copy an Iterator-to-mutable (reader+writer) to
+    // Iterator-to-const (reader-only), but not the reverse.
+    template <bool IsRhsBufferConst,
+              typename = std::enable_if_t<(!IsRhsBufferConst) && IsBufferConst>>
+    MOZ_IMPLICIT Iterator(const Iterator<IsRhsBufferConst>& aRhs)
+        : mModuloBuffer(aRhs.mModuloBuffer), mIndex(aRhs.mIndex) {}
+
+    // Can implicitly assign from an Iterator-to-mutable (reader+writer) to
+    // Iterator-to-const (reader-only), but not the reverse.
+    template <bool IsRhsBufferConst,
+              typename = std::enable_if_t<(!IsRhsBufferConst) && IsBufferConst>>
+    Iterator& operator=(const Iterator<IsRhsBufferConst>& aRhs) {
+      mModuloBuffer = aRhs.mModuloBuffer;
+      mIndex = aRhs.mIndex;
+      return *this;
+    }
+
+    // Current location of the iterator in the `Index` range.
+    // Note that due to wrapping, multiple indices may effectively point at the
+    // same byte in the buffer.
+    Index CurrentIndex() const { return mIndex; }
+
+    // Location comparison in the `Index` range. I.e., two `Iterator`s may look
+    // unequal, but refer to the same buffer location.
+    // Must be on the same buffer.
+    bool operator==(const Iterator& aRhs) const {
+      MOZ_ASSERT(mModuloBuffer == aRhs.mModuloBuffer);
+      return mIndex == aRhs.mIndex;
+    }
+    bool operator!=(const Iterator& aRhs) const {
+      MOZ_ASSERT(mModuloBuffer == aRhs.mModuloBuffer);
+      return mIndex != aRhs.mIndex;
+    }
+    bool operator<(const Iterator& aRhs) const {
+      MOZ_ASSERT(mModuloBuffer == aRhs.mModuloBuffer);
+      return mIndex < aRhs.mIndex;
+    }
+    bool operator<=(const Iterator& aRhs) const {
+      MOZ_ASSERT(mModuloBuffer == aRhs.mModuloBuffer);
+      return mIndex <= aRhs.mIndex;
+    }
+    bool operator>(const Iterator& aRhs) const {
+      MOZ_ASSERT(mModuloBuffer == aRhs.mModuloBuffer);
+      return mIndex > aRhs.mIndex;
+    }
+    bool operator>=(const Iterator& aRhs) const {
+      MOZ_ASSERT(mModuloBuffer == aRhs.mModuloBuffer);
+      return mIndex >= aRhs.mIndex;
+    }
+
+    // Movement in the `Index` range.
+    Iterator& operator++() {
+      ++mIndex;
+      return *this;
+    }
+    Iterator operator++(int) {
+      Iterator here(*mModuloBuffer, mIndex);
+      ++mIndex;
+      return here;
+    }
+    Iterator& operator--() {
+      --mIndex;
+      return *this;
+    }
+    Iterator operator--(int) {
+      Iterator here(*mModuloBuffer, mIndex);
+      --mIndex;
+      return here;
+    }
+    Iterator& operator+=(Length aLength) {
+      mIndex += aLength;
+      return *this;
+    }
+    Iterator operator+(Length aLength) const {
+      return Iterator(*mModuloBuffer, mIndex + aLength);
+    }
+    friend Iterator operator+(Length aLength, const Iterator& aIt) {
+      return aIt + aLength;
+    }
+    Iterator& operator-=(Length aLength) {
+      mIndex -= aLength;
+      return *this;
+    }
+    Iterator operator-(Length aLength) const {
+      return Iterator(*mModuloBuffer, mIndex - aLength);
+    }
+
+    // Distance from `aRef` to here in the `Index` range.
+    // May be negative (as 2's complement) if `aRef > *this`.
+    Index operator-(const Iterator& aRef) const {
+      MOZ_ASSERT(mModuloBuffer == aRef.mModuloBuffer);
+      return mIndex - aRef.mIndex;
+    }
+
+    // Dereference a single byte (read-only if `IsBufferConst` is true).
+    reference operator*() const {
+      return mModuloBuffer->mBuffer[OffsetInBuffer()];
+    }
+
+    // Random-access dereference.
+    reference operator[](Length aLength) const { return *(*this + aLength); }
+
+    // Write data (if `IsBufferConst` is false) but don't move iterator.
+    template <bool NotIsBufferConst = !IsBufferConst>
+    std::enable_if_t<NotIsBufferConst> Poke(const void* aSrc,
+                                            Length aLength) const {
+      // Don't allow data larger than the buffer.
+      MOZ_ASSERT(aLength <= mModuloBuffer->BufferLength().Value());
+      // Offset inside the buffer (corresponding to our Index).
+      Offset offset = OffsetInBuffer();
+      // Compute remaining bytes between this offset and the end of the buffer.
+      Length remaining = mModuloBuffer->BufferLength().Value() - offset;
+      if (MOZ_LIKELY(remaining >= aLength)) {
+        // Enough space to write everything before the end.
+        memcpy(&mModuloBuffer->mBuffer[offset], aSrc, aLength);
+      } else {
+        // Not enough space. Write as much as possible before the end.
+        memcpy(&mModuloBuffer->mBuffer[offset], aSrc, remaining);
+        // And then continue from the beginning of the buffer.
+        memcpy(&mModuloBuffer->mBuffer[0],
+               static_cast<const Byte*>(aSrc) + remaining,
+               (aLength - remaining));
+      }
+    }
+
+    // Write object data (if `IsBufferConst` is false) but don't move iterator.
+    // Note that this copies bytes from the object, with the intent to read them
+    // back later. Restricted to trivially-copyable types, which support this
+    // without Undefined Behavior!
+    template <typename T, bool NotIsBufferConst = !IsBufferConst>
+    std::enable_if_t<NotIsBufferConst> PokeObject(const T& aObject) const {
+      static_assert(std::is_trivially_copyable<T>::value,
+                    "PokeObject<T> - T must be trivially copyable");
+      return Poke(&aObject, sizeof(T));
+    }
+
+    // Write data (if `IsBufferConst` is false) and move iterator ahead.
+    template <bool NotIsBufferConst = !IsBufferConst>
+    std::enable_if_t<NotIsBufferConst> Write(const void* aSrc, Length aLength) {
+      Poke(aSrc, aLength);
+      mIndex += aLength;
+    }
+
+    // Write object data (if `IsBufferConst` is false) and move iterator ahead.
+    // Note that this copies bytes from the object, with the intent to read them
+    // back later. Restricted to trivially-copyable types, which support this
+    // without Undefined Behavior!
+    template <typename T, bool NotIsBufferConst = !IsBufferConst>
+    std::enable_if_t<NotIsBufferConst> WriteObject(const T& aObject) {
+      static_assert(std::is_trivially_copyable<T>::value,
+                    "WriteObject<T> - T must be trivially copyable");
+      return Write(&aObject, sizeof(T));
+    }
+
+    // Number of bytes needed to represent `aValue` in unsigned LEB128.
+    template <typename T>
+    static unsigned ULEB128Size(T aValue) {
+      return ::mozilla::ULEB128Size(aValue);
+    }
+
+    // Write number as unsigned LEB128 (if `IsBufferConst` is false) and move
+    // iterator ahead.
+    template <typename T, bool NotIsBufferConst = !IsBufferConst>
+    std::enable_if_t<NotIsBufferConst> WriteULEB128(T aValue) {
+      ::mozilla::WriteULEB128(aValue, *this);
+    }
+
+    // Read data but don't move iterator.
+    void Peek(void* aDst, Length aLength) const {
+      // Don't allow data larger than the buffer.
+      MOZ_ASSERT(aLength <= mModuloBuffer->BufferLength().Value());
+      // Offset inside the buffer (corresponding to our Index).
+      Offset offset = OffsetInBuffer();
+      // Compute remaining bytes between this offset and the end of the buffer.
+      Length remaining = mModuloBuffer->BufferLength().Value() - offset;
+      if (MOZ_LIKELY(remaining >= aLength)) {
+        // Can read everything we need before the end of the buffer.
+        memcpy(aDst, &mModuloBuffer->mBuffer[offset], aLength);
+      } else {
+        // Read as much as possible before the end of the buffer.
+        memcpy(aDst, &mModuloBuffer->mBuffer[offset], remaining);
+        // And then continue from the beginning of the buffer.
+        memcpy(static_cast<Byte*>(aDst) + remaining, &mModuloBuffer->mBuffer[0],
+               (aLength - remaining));
+      }
+    }
+
+    // Read data into an object but don't move iterator.
+    // Note that this overwrites `aObject` with bytes from the buffer.
+    // Restricted to trivially-copyable types, which support this without
+    // Undefined Behavior!
+    template <typename T>
+    void PeekIntoObject(T& aObject) const {
+      static_assert(std::is_trivially_copyable<T>::value,
+                    "PeekIntoObject<T> - T must be trivially copyable");
+      Peek(&aObject, sizeof(T));
+    }
+
+    // Read data as an object but don't move iterator.
+    // Note that this creates an default `T` first, and then overwrites it with
+    // bytes from the buffer. Restricted to trivially-copyable types, which
+    // support this without Undefined Behavior!
+    template <typename T>
+    T PeekObject() const {
+      static_assert(std::is_trivially_copyable<T>::value,
+                    "PeekObject<T> - T must be trivially copyable");
+      T object;
+      PeekIntoObject(object);
+      return object;
+    }
+
+    // Read data and move iterator ahead.
+    void Read(void* aDst, Length aLength) {
+      Peek(aDst, aLength);
+      mIndex += aLength;
+    }
+
+    // Read data into a mutable iterator and move both iterators ahead.
+    void ReadInto(Iterator</* IsBufferConst */ false>& aDst, Length aLength) {
+      // Don't allow data larger than the buffer.
+      MOZ_ASSERT(aLength <= mModuloBuffer->BufferLength().Value());
+      MOZ_ASSERT(aLength <= aDst.mModuloBuffer->BufferLength().Value());
+      // Offset inside the buffer (corresponding to our Index).
+      Offset offset = OffsetInBuffer();
+      // Compute remaining bytes between this offset and the end of the buffer.
+      Length remaining = mModuloBuffer->BufferLength().Value() - offset;
+      if (MOZ_LIKELY(remaining >= aLength)) {
+        // Can read everything we need before the end of the buffer.
+        aDst.Write(&mModuloBuffer->mBuffer[offset], aLength);
+      } else {
+        // Read as much as possible before the end of the buffer.
+        aDst.Write(&mModuloBuffer->mBuffer[offset], remaining);
+        // And then continue from the beginning of the buffer.
+        aDst.Write(&mModuloBuffer->mBuffer[0], (aLength - remaining));
+      }
+      mIndex += aLength;
+    }
+
+    // Read data into an object and move iterator ahead.
+    // Note that this overwrites `aObject` with bytes from the buffer.
+    // Restricted to trivially-copyable types, which support this without
+    // Undefined Behavior!
+    template <typename T>
+    void ReadIntoObject(T& aObject) {
+      static_assert(std::is_trivially_copyable<T>::value,
+                    "ReadIntoObject<T> - T must be trivially copyable");
+      Read(&aObject, sizeof(T));
+    }
+
+    // Read data as an object and move iterator ahead.
+    // Note that this creates an default `T` first, and then overwrites it with
+    // bytes from the buffer. Restricted to trivially-copyable types, which
+    // support this without Undefined Behavior!
+    template <typename T>
+    T ReadObject() {
+      static_assert(std::is_trivially_copyable<T>::value,
+                    "ReadObject<T> - T must be trivially copyable");
+      T object;
+      ReadIntoObject(object);
+      return object;
+    }
+
+    // Read an unsigned LEB128 number and move iterator ahead.
+    template <typename T>
+    T ReadULEB128() {
+      return ::mozilla::ReadULEB128<T>(*this);
+    }
+
+   private:
+    // Only a ModuloBuffer can instantiate its iterator.
+    friend class ModuloBuffer;
+
+    Iterator(ConstOrMutableBuffer& aBuffer, Index aIndex)
+        : mModuloBuffer(WrapNotNull(&aBuffer)), mIndex(aIndex) {}
+
+    // Convert the Iterator's mIndex into an offset inside the byte buffer.
+    Offset OffsetInBuffer() const {
+      return static_cast<Offset>(mIndex) & mModuloBuffer->mMask;
+    }
+
+    // ModuloBuffer that this Iterator operates on.
+    // Using a non-null pointer instead of a reference, to allow re-assignment
+    // of an Iterator variable.
+    NotNull<ConstOrMutableBuffer*> mModuloBuffer;
+
+    // Position of this iterator in the wider `Index` range. (Will be wrapped
+    // around as needed when actually accessing bytes from the buffer.)
+    Index mIndex;
+  };
+
+  // Shortcut to iterator to const (read-only) data.
+  using Reader = Iterator<true>;
+  // Shortcut to iterator to non-const (read/write) data.
+  using Writer = Iterator<false>;
+
+  // Create an iterator to const data at the given index.
+  Reader ReaderAt(Index aIndex) const { return Reader(*this, aIndex); }
+
+  // Create an iterator to non-const data at the given index.
+  Writer WriterAt(Index aIndex) { return Writer(*this, aIndex); }
+
+#ifdef DEBUG
+  void Dump() const {
+    Length len = BufferLength().Value();
+    if (len > 128) {
+      len = 128;
+    }
+    for (Length i = 0; i < len; ++i) {
+      printf("%02x ", mBuffer[i]);
+    }
+    printf("\n");
+  }
+#endif  // DEBUG
+
+ private:
+  // Mask used to convert an index to an offset in `mBuffer`
+  const PowerOfTwoMask<Offset> mMask;
+
+  // Buffer data. `const NotNull<...>` shows that `mBuffer is `const`, and
+  // `Byte* const` shows that the pointer cannot be changed to point at
+  // something else, but the pointed-at `Byte`s are writable.
+  const NotNull<Byte* const> mBuffer;
+
+  // Function used to release the buffer resource (if needed).
+  std::function<void(Byte*)> mBufferDeleter;
+};
+
+}  // namespace mozilla
+
+#endif  // ModuloBuffer_h
diff --git a/mozglue/baseprofiler/public/PowerOfTwo.h b/mozglue/baseprofiler/public/PowerOfTwo.h
new file mode 100644
index 0000000000..07f9a3fdb4
--- /dev/null
+++ b/mozglue/baseprofiler/public/PowerOfTwo.h
@@ -0,0 +1,320 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// PowerOfTwo is a value type that always hold a power of 2.
+// It has the same size as their underlying unsigned type, but offer the
+// guarantee of being a power of 2, which permits some optimizations when
+// involved in modulo operations (using masking instead of actual modulo).
+//
+// PowerOfTwoMask contains a mask corresponding to a power of 2.
+// E.g., 2^8 is 256 or 0x100, the corresponding mask is 2^8-1 or 255 or 0xFF.
+// It should be used instead of PowerOfTwo in situations where most operations
+// would be modulo, this saves having to recompute the mask from the stored
+// power of 2.
+//
+// One common use would be for ring-buffer containers with a power-of-2 size,
+// where an index is usually converted to an in-buffer offset by `i % size`.
+// Instead, the container could store a PowerOfTwo or PowerOfTwoMask, and do
+// `i % p2` or `i & p2m`, which is more efficient than for arbitrary sizes.
+//
+// Shortcuts for common 32- and 64-bit values: PowerOfTwo32, etc.
+//
+// To create constexpr constants, use MakePowerOfTwo<Type, Value>(), etc.
+
+#ifndef PowerOfTwo_h
+#define PowerOfTwo_h
+
+#include "mozilla/MathAlgorithms.h"
+
+#include <limits>
+
+namespace mozilla {
+
+// Compute the smallest power of 2 greater than or equal to aInput, except if
+// that would overflow in which case the highest possible power of 2 if chosen.
+// 0->1, 1->1, 2->2, 3->4, ... 2^31->2^31, 2^31+1->2^31 (for uint32_t), etc.
+template <typename T>
+T FriendlyRoundUpPow2(T aInput) {
+  // This is the same code as `RoundUpPow2()`, except we handle any type (that
+  // CeilingLog2 supports) and allow the greater-than-max-power case.
+  constexpr T max = T(1) << (sizeof(T) * CHAR_BIT - 1);
+  if (aInput >= max) {
+    return max;
+  }
+  return T(1) << CeilingLog2(aInput);
+}
+
+namespace detail {
+// Same function name `CountLeadingZeroes` with uint32_t and uint64_t overloads.
+inline uint_fast8_t CountLeadingZeroes(uint32_t aValue) {
+  MOZ_ASSERT(aValue != 0);
+  return detail::CountLeadingZeroes32(aValue);
+}
+inline uint_fast8_t CountLeadingZeroes(uint64_t aValue) {
+  MOZ_ASSERT(aValue != 0);
+  return detail::CountLeadingZeroes64(aValue);
+}
+// Refuse anything else.
+template <typename T>
+inline uint_fast8_t CountLeadingZeroes(T aValue) = delete;
+}  // namespace detail
+
+// Compute the smallest 2^N-1 mask where aInput can fit.
+// I.e., `x & mask == x`, but `x & (mask >> 1) != x`.
+// Or looking at binary, we want a mask with as many leading zeroes as the
+// input, by right-shifting a full mask: (8-bit examples)
+// input:          00000000    00000001   00000010  00010110  01111111 10000000
+// N leading 0s:   ^^^^^^^^ 8  ^^^^^^^ 7  ^^^^^^ 6  ^^^ 3     ^ 1      0
+// full mask:      11111111    11111111   11111111  11111111  11111111 11111111
+// full mask >> N: 00000000    00000001   00000011  00011111  01111111 11111111
+template <typename T>
+T RoundUpPow2Mask(T aInput) {
+  // Special case, as CountLeadingZeroes(0) is undefined. (And even if that was
+  // defined, shifting by the full type size is also undefined!)
+  if (aInput == 0) {
+    return 0;
+  }
+  return T(-1) >> detail::CountLeadingZeroes(aInput);
+}
+
+template <typename T>
+class PowerOfTwoMask;
+
+template <typename T, T Mask>
+constexpr PowerOfTwoMask<T> MakePowerOfTwoMask();
+
+template <typename T>
+class PowerOfTwo;
+
+template <typename T, T Value>
+constexpr PowerOfTwo<T> MakePowerOfTwo();
+
+// PowerOfTwoMask will always contain a mask for a power of 2, which is useful
+// for power-of-2 modulo operations (e.g., to keep an index inside a power-of-2
+// container).
+// Use this instead of PowerOfTwo if masking is the primary use of the value.
+//
+// Note that this class can store a "full" mask where all bits are set, so it
+// works for mask corresponding to the power of 2 that would overflow `T`
+// (e.g., 2^32 for uint32_t gives a mask of 2^32-1, which fits in a uint32_t).
+// For this reason there is no API that computes the power of 2 corresponding to
+// the mask; But this can be done explicitly with `MaskValue() + 1`, which may
+// be useful for computing things like distance-to-the-end by doing
+// `MaskValue() + 1 - offset`, which works fine with unsigned number types.
+template <typename T>
+class PowerOfTwoMask {
+  static_assert(!std::numeric_limits<T>::is_signed,
+                "PowerOfTwoMask must use an unsigned type");
+
+ public:
+  // Construct a power of 2 mask where the given value can fit.
+  // Cannot be constexpr because of `RoundUpPow2Mask()`.
+  explicit PowerOfTwoMask(T aInput) : mMask(RoundUpPow2Mask(aInput)) {}
+
+  // Compute the mask corresponding to a PowerOfTwo.
+  // This saves having to compute the nearest 2^N-1.
+  // Not a conversion constructor, as that could be ambiguous whether we'd want
+  // the mask corresponding to the power of 2 (2^N -> 2^N-1), or the mask that
+  // can *contain* the PowerOfTwo value (2^N -> 2^(N+1)-1).
+  // Note: Not offering reverse PowerOfTwoMark-to-PowerOfTwo conversion, because
+  // that could result in an unexpected 0 result for the largest possible mask.
+  template <typename U>
+  static constexpr PowerOfTwoMask<U> MaskForPowerOfTwo(
+      const PowerOfTwo<U>& aP2) {
+    return PowerOfTwoMask(aP2);
+  }
+
+  // Allow smaller unsigned types as input.
+  // Bigger or signed types must be explicitly converted by the caller.
+  template <typename U>
+  explicit constexpr PowerOfTwoMask(U aInput)
+      : mMask(RoundUpPow2Mask(static_cast<T>(aInput))) {
+    static_assert(!std::numeric_limits<T>::is_signed,
+                  "PowerOfTwoMask does not accept signed types");
+    static_assert(sizeof(U) <= sizeof(T),
+                  "PowerOfTwoMask does not accept bigger types");
+  }
+
+  constexpr T MaskValue() const { return mMask; }
+
+  // `x & aPowerOfTwoMask` just works.
+  template <typename U>
+  friend U operator&(U aNumber, PowerOfTwoMask aP2M) {
+    return static_cast<U>(aNumber & aP2M.MaskValue());
+  }
+
+  // `aPowerOfTwoMask & x` just works.
+  template <typename U>
+  friend constexpr U operator&(PowerOfTwoMask aP2M, U aNumber) {
+    return static_cast<U>(aP2M.MaskValue() & aNumber);
+  }
+
+  // `x % aPowerOfTwoMask(2^N-1)` is equivalent to `x % 2^N` but is more
+  // optimal by doing `x & (2^N-1)`.
+  // Useful for templated code doing modulo with a template argument type.
+  template <typename U>
+  friend constexpr U operator%(U aNumerator, PowerOfTwoMask aDenominator) {
+    return aNumerator & aDenominator.MaskValue();
+  }
+
+  constexpr bool operator==(const PowerOfTwoMask& aRhs) const {
+    return mMask == aRhs.mMask;
+  }
+  constexpr bool operator!=(const PowerOfTwoMask& aRhs) const {
+    return mMask != aRhs.mMask;
+  }
+
+ private:
+  // Trust `PowerOfTwo` to call the private Trusted constructor below.
+  friend class PowerOfTwo<T>;
+
+  // Trust `MakePowerOfTwoMask()` to call the private Trusted constructor below.
+  template <typename U, U Mask>
+  friend constexpr PowerOfTwoMask<U> MakePowerOfTwoMask();
+
+  struct Trusted {
+    T mMask;
+  };
+  // Construct the mask corresponding to a PowerOfTwo.
+  // This saves having to compute the nearest 2^N-1.
+  // Note: Not a public PowerOfTwo->PowerOfTwoMask conversion constructor, as
+  // that could be ambiguous whether we'd want the mask corresponding to the
+  // power of 2 (2^N -> 2^N-1), or the mask that can *contain* the PowerOfTwo
+  // value (2^N -> 2^(N+1)-1).
+  explicit constexpr PowerOfTwoMask(const Trusted& aP2) : mMask(aP2.mMask) {}
+
+  T mMask = 0;
+};
+
+// Make a PowerOfTwoMask constant, statically-checked.
+template <typename T, T Mask>
+constexpr PowerOfTwoMask<T> MakePowerOfTwoMask() {
+  static_assert(Mask == T(-1) || IsPowerOfTwo(Mask + 1),
+                "MakePowerOfTwoMask<T, Mask>: Mask must be 2^N-1");
+  using Trusted = typename PowerOfTwoMask<T>::Trusted;
+  return PowerOfTwoMask<T>(Trusted{Mask});
+}
+
+// PowerOfTwo will always contain a power of 2.
+template <typename T>
+class PowerOfTwo {
+  static_assert(!std::numeric_limits<T>::is_signed,
+                "PowerOfTwo must use an unsigned type");
+
+ public:
+  // Construct a power of 2 that can fit the given value, or the highest power
+  // of 2 possible.
+  // Caller should explicitly check/assert `Value() <= aInput` if they want to.
+  // Cannot be constexpr because of `FriendlyRoundUpPow2()`.
+  explicit PowerOfTwo(T aInput) : mValue(FriendlyRoundUpPow2(aInput)) {}
+
+  // Allow smaller unsigned types as input.
+  // Bigger or signed types must be explicitly converted by the caller.
+  template <typename U>
+  explicit PowerOfTwo(U aInput)
+      : mValue(FriendlyRoundUpPow2(static_cast<T>(aInput))) {
+    static_assert(!std::numeric_limits<T>::is_signed,
+                  "PowerOfTwo does not accept signed types");
+    static_assert(sizeof(U) <= sizeof(T),
+                  "PowerOfTwo does not accept bigger types");
+  }
+
+  constexpr T Value() const { return mValue; }
+
+  // Binary mask corresponding to the power of 2, useful for modulo.
+  // E.g., `x & powerOfTwo(y).Mask()` == `x % powerOfTwo(y)`.
+  // Consider PowerOfTwoMask class instead of PowerOfTwo if masking is the
+  // primary use case.
+  constexpr T MaskValue() const { return mValue - 1; }
+
+  // PowerOfTwoMask corresponding to this power of 2, useful for modulo.
+  constexpr PowerOfTwoMask<T> Mask() const {
+    using Trusted = typename PowerOfTwoMask<T>::Trusted;
+    return PowerOfTwoMask<T>(Trusted{MaskValue()});
+  }
+
+  // `x % aPowerOfTwo` works optimally.
+  // Useful for templated code doing modulo with a template argument type.
+  // Use PowerOfTwoMask class instead if masking is the primary use case.
+  template <typename U>
+  friend constexpr U operator%(U aNumerator, PowerOfTwo aDenominator) {
+    return aNumerator & aDenominator.MaskValue();
+  }
+
+  constexpr bool operator==(const PowerOfTwo& aRhs) const {
+    return mValue == aRhs.mValue;
+  }
+  constexpr bool operator!=(const PowerOfTwo& aRhs) const {
+    return mValue != aRhs.mValue;
+  }
+  constexpr bool operator<(const PowerOfTwo& aRhs) const {
+    return mValue < aRhs.mValue;
+  }
+  constexpr bool operator<=(const PowerOfTwo& aRhs) const {
+    return mValue <= aRhs.mValue;
+  }
+  constexpr bool operator>(const PowerOfTwo& aRhs) const {
+    return mValue > aRhs.mValue;
+  }
+  constexpr bool operator>=(const PowerOfTwo& aRhs) const {
+    return mValue >= aRhs.mValue;
+  }
+
+ private:
+  // Trust `MakePowerOfTwo()` to call the private Trusted constructor below.
+  template <typename U, U Value>
+  friend constexpr PowerOfTwo<U> MakePowerOfTwo();
+
+  struct Trusted {
+    T mValue;
+  };
+  // Construct a PowerOfTwo with the given trusted value.
+  // This saves having to compute the nearest 2^N.
+  // Note: Not offering PowerOfTwoMark-to-PowerOfTwo conversion, because that
+  // could result in an unexpected 0 result for the largest possible mask.
+  explicit constexpr PowerOfTwo(const Trusted& aP2) : mValue(aP2.mValue) {}
+
+  // The smallest power of 2 is 2^0 == 1.
+  T mValue = 1;
+};
+
+// Make a PowerOfTwo constant, statically-checked.
+template <typename T, T Value>
+constexpr PowerOfTwo<T> MakePowerOfTwo() {
+  static_assert(IsPowerOfTwo(Value),
+                "MakePowerOfTwo<T, Value>: Value must be 2^N");
+  using Trusted = typename PowerOfTwo<T>::Trusted;
+  return PowerOfTwo<T>(Trusted{Value});
+}
+
+// Shortcuts for the most common types and functions.
+
+using PowerOfTwoMask32 = PowerOfTwoMask<uint32_t>;
+using PowerOfTwo32 = PowerOfTwo<uint32_t>;
+using PowerOfTwoMask64 = PowerOfTwoMask<uint64_t>;
+using PowerOfTwo64 = PowerOfTwo<uint64_t>;
+
+template <uint32_t Mask>
+constexpr PowerOfTwoMask32 MakePowerOfTwoMask32() {
+  return MakePowerOfTwoMask<uint32_t, Mask>();
+}
+
+template <uint32_t Value>
+constexpr PowerOfTwo32 MakePowerOfTwo32() {
+  return MakePowerOfTwo<uint32_t, Value>();
+}
+
+template <uint64_t Mask>
+constexpr PowerOfTwoMask64 MakePowerOfTwoMask64() {
+  return MakePowerOfTwoMask<uint64_t, Mask>();
+}
+
+template <uint64_t Value>
+constexpr PowerOfTwo64 MakePowerOfTwo64() {
+  return MakePowerOfTwo<uint64_t, Value>();
+}
+
+}  // namespace mozilla
+
+#endif  // PowerOfTwo_h
diff --git a/mozglue/baseprofiler/public/leb128iterator.h b/mozglue/baseprofiler/public/leb128iterator.h
new file mode 100644
index 0000000000..8a0d6bf7bb
--- /dev/null
+++ b/mozglue/baseprofiler/public/leb128iterator.h
@@ -0,0 +1,145 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// LEB128 utilities that can read/write unsigned LEB128 numbers from/to
+// iterators.
+//
+// LEB128 = Little Endian Base 128, where small numbers take few bytes, but
+// large numbers are still allowed, which is ideal when serializing numbers that
+// are likely to be small.
+// Each byte contains 7 bits from the number, starting at the "little end", the
+// top bit is 0 for the last byte, 1 otherwise.
+// Numbers 0-127 only take 1 byte. 128-16383 take 2 bytes. Etc.
+//
+// Iterators only need to provide:
+// - `*it` to return a reference to the next byte to be read from or written to.
+// - `++it` to advance the iterator after a byte is written.
+//
+// The caller must always provide sufficient space to write any number, by:
+// - pre-allocating a large enough buffer, or
+// - allocating more space when `++it` reaches the end and/or `*it` is invoked
+//   after the end, or
+// - moving the underlying pointer to an appropriate location (e.g., wrapping
+//   around a circular buffer).
+// The caller must also provide enough bytes to read a full value (i.e., at
+// least one byte should have its top bit unset), and a type large enough to
+// hold the stored value.
+//
+// Note: There are insufficient checks for validity! These functions are
+// intended to be used together, i.e., the user should only `ReadULEB128()` from
+// a sufficiently-large buffer that the same user filled with `WriteULEB128()`.
+// Using with externally-sourced data (e.g., DWARF) is *not* recommended.
+//
+// https://en.wikipedia.org/wiki/LEB128
+
+#ifndef leb128iterator_h
+#define leb128iterator_h
+
+#include <climits>
+#include <cstdint>
+#include <limits>
+#include <type_traits>
+
+namespace mozilla {
+
+// Number of bytes needed to represent `aValue`.
+template <typename T>
+constexpr uint_fast8_t ULEB128Size(T aValue) {
+  static_assert(!std::numeric_limits<T>::is_signed,
+                "ULEB128Size only takes unsigned types");
+  // We need one output byte per 7 bits of non-zero value. So we just remove
+  // 7 least significant bits at a time until the value becomes zero.
+  // Note the special case of 0, which still needs 1 output byte; this is done
+  // by starting the first loop before we check for 0.
+  uint_fast8_t size = 0;
+  for (;;) {
+    size += 1;
+    aValue >>= 7;
+    // Expecting small values, so it should be more likely that `aValue == 0`.
+    if (MOZ_LIKELY(aValue == 0)) {
+      return size;
+    }
+  }
+}
+
+// Maximum number of bytes needed to represent any value of type `T`.
+template <typename T>
+constexpr uint_fast8_t ULEB128MaxSize() {
+  return ULEB128Size<T>(std::numeric_limits<T>::max());
+}
+
+// Write `aValue` in LEB128 to `aIterator`.
+// The iterator will be moved past the last byte.
+template <typename T, typename It>
+void WriteULEB128(T aValue, It& aIterator) {
+  static_assert(!std::numeric_limits<T>::is_signed,
+                "WriteULEB128 only takes unsigned types");
+  using IteratorValue = std::remove_reference_t<decltype(*aIterator)>;
+  static_assert(sizeof(IteratorValue) == 1,
+                "WriteULEB128 expects an iterator to single bytes");
+  // 0. Don't test for 0 yet, as we want to output one byte for it.
+  for (;;) {
+    // 1. Extract the 7 least significant bits.
+    const uint_fast8_t byte = aValue & 0x7Fu;
+    // 2. Remove them from `aValue`.
+    aValue >>= 7;
+    // 3. Write the 7 bits, and set the 8th bit if `aValue` is not 0 yet
+    // (meaning there will be more bytes after this one.)
+    // Expecting small values, so it should be more likely that `aValue == 0`.
+    // Note: No absolute need to force-cast to IteratorValue, because we have
+    // only changed the bottom 8 bits above. However the compiler could warn
+    // about a narrowing conversion from potentially-multibyte uint_fast8_t down
+    // to whatever single-byte type `*iterator* expects, so we make it explicit.
+    *aIterator = static_cast<IteratorValue>(
+        MOZ_LIKELY(aValue == 0) ? byte : (byte | 0x80u));
+    // 4. Always advance the iterator to the next byte.
+    ++aIterator;
+    // 5. We're done if `aValue` is 0.
+    // Expecting small values, so it should be more likely that `aValue == 0`.
+    if (MOZ_LIKELY(aValue == 0)) {
+      return;
+    }
+  }
+}
+
+// Read an LEB128 value from `aIterator`.
+// The iterator will be moved past the last byte.
+template <typename T, typename It>
+T ReadULEB128(It& aIterator) {
+  static_assert(!std::numeric_limits<T>::is_signed,
+                "ReadULEB128 must return an unsigned type");
+  using IteratorValue = std::remove_reference_t<decltype(*aIterator)>;
+  static_assert(sizeof(IteratorValue) == 1,
+                "ReadULEB128 expects an iterator to single bytes");
+  // Incoming bits will be added to `result`...
+  T result = 0;
+  // ... starting with the least significant bits.
+  uint_fast8_t shift = 0;
+  for (;;) {
+    // 1. Read one byte from the iterator.
+    // `static_cast` just in case IteratorValue is not implicitly convertible to
+    // uint_fast8_t. It wouldn't matter if the sign was extended, we're only
+    // dealing with the bottom 8 bits below.
+    const uint_fast8_t byte = static_cast<uint_fast8_t>(*aIterator);
+    // 2. Always advance the iterator.
+    ++aIterator;
+    // 3. Extract the 7 bits of value, and shift them in place into `result`.
+    result |= static_cast<T>(byte & 0x7fu) << shift;
+    // 4. If the 8th bit is *not* set, this was the last byte.
+    // Expecting small values, so it should be more likely that the bit is off.
+    if (MOZ_LIKELY((byte & 0x80u) == 0)) {
+      return result;
+    }
+    // There are more bytes to read.
+    // 5. Next byte will contain more significant bits above the past 7.
+    shift += 7;
+    // Safety check that we're not going to shift by >= than the type size,
+    // which is Undefined Behavior in C++.
+    MOZ_ASSERT(shift < CHAR_BIT * sizeof(T));
+  }
+}
+
+}  // namespace mozilla
+
+#endif  // leb128iterator_h
diff --git a/mozglue/misc/AutoProfilerLabel.cpp b/mozglue/misc/AutoProfilerLabel.cpp
index 587d274add..da1e063780 100644
--- a/mozglue/misc/AutoProfilerLabel.cpp
+++ b/mozglue/misc/AutoProfilerLabel.cpp
@@ -4,15 +4,65 @@
 
 #include "mozilla/AutoProfilerLabel.h"
 
+#include "mozilla/PlatformMutex.h"
+
 namespace mozilla {
 
-static ProfilerLabelEnter sEnter = nullptr;
-static ProfilerLabelExit sExit = nullptr;
+// RAII class that encapsulates all shared static data, and enforces locking
+// when accessing this data.
+class MOZ_RAII AutoProfilerLabelData {
+ public:
+  AutoProfilerLabelData() { sAPLMutex.Lock(); }
+
+  ~AutoProfilerLabelData() { sAPLMutex.Unlock(); }
+
+  AutoProfilerLabelData(const AutoProfilerLabelData&) = delete;
+  void operator=(const AutoProfilerLabelData&) = delete;
+
+  const ProfilerLabelEnter& EnterCRef() const { return sEnter; }
+  ProfilerLabelEnter& EnterRef() { return sEnter; }
+
+  const ProfilerLabelExit& ExitCRef() const { return sExit; }
+  ProfilerLabelExit& ExitRef() { return sExit; }
+
+  const uint32_t& GenerationCRef() const { return sGeneration; }
+  uint32_t& GenerationRef() { return sGeneration; }
+
+ private:
+  // Thin shell around mozglue PlatformMutex, for local internal use.
+  class Mutex : private mozilla::detail::MutexImpl {
+   public:
+    Mutex()
+        : mozilla::detail::MutexImpl() {}
+    void Lock() { mozilla::detail::MutexImpl::lock(); }
+    void Unlock() { mozilla::detail::MutexImpl::unlock(); }
+  };
+
+  // Mutex protecting access to the following static members.
+  static Mutex sAPLMutex;
+
+  static ProfilerLabelEnter sEnter;
+  static ProfilerLabelExit sExit;
+
+  // Current "generation" of RegisterProfilerLabelEnterExit calls.
+  static uint32_t sGeneration;
+};
+
+/* static */ AutoProfilerLabelData::Mutex AutoProfilerLabelData::sAPLMutex;
+/* static */ ProfilerLabelEnter AutoProfilerLabelData::sEnter = nullptr;
+/* static */ ProfilerLabelExit AutoProfilerLabelData::sExit = nullptr;
+/* static */ uint32_t AutoProfilerLabelData::sGeneration = 0;
 
 void RegisterProfilerLabelEnterExit(ProfilerLabelEnter aEnter,
                                     ProfilerLabelExit aExit) {
-  sEnter = aEnter;
-  sExit = aExit;
+  MOZ_ASSERT(!aEnter == !aExit, "Must provide both null or both non-null");
+
+  AutoProfilerLabelData data;
+  MOZ_ASSERT(!aEnter != !data.EnterRef(),
+             "Must go from null to non-null, or from non-null to null");
+  data.EnterRef() = aEnter;
+  data.ExitRef() = aExit;
+  ++data.GenerationRef();
 }
 
 AutoProfilerLabel::AutoProfilerLabel(
@@ -20,12 +70,20 @@ AutoProfilerLabel::AutoProfilerLabel(
     const char* aDynamicString MOZ_GUARD_OBJECT_NOTIFIER_PARAM_IN_IMPL) {
   MOZ_GUARD_OBJECT_NOTIFIER_INIT;
 
-  mProfilingStack = sEnter ? sEnter(aLabel, aDynamicString, this) : nullptr;
+  const AutoProfilerLabelData data;
+  mEntryContext = (data.EnterCRef())
+                      ? data.EnterCRef()(aLabel, aDynamicString, this)
+                      : nullptr;
+  mGeneration = data.GenerationCRef();
 }
 
 AutoProfilerLabel::~AutoProfilerLabel() {
-  if (sExit && mProfilingStack) {
-    sExit(mProfilingStack);
+  if (!mEntryContext) {
+    return;
+  }
+  const AutoProfilerLabelData data;
+  if (data.ExitCRef() && (mGeneration == data.GenerationCRef())) {
+    data.ExitCRef()(mEntryContext);
   }
 }
 
diff --git a/mozglue/misc/AutoProfilerLabel.h b/mozglue/misc/AutoProfilerLabel.h
index 1db3a0b4d4..086091fe75 100644
--- a/mozglue/misc/AutoProfilerLabel.h
+++ b/mozglue/misc/AutoProfilerLabel.h
@@ -23,12 +23,12 @@
 // this file would require #including ProfilingCategory.h in mozglue, which we
 // don't want to do.)
 
-class ProfilingStack;
-
 namespace mozilla {
 
-typedef ProfilingStack* (*ProfilerLabelEnter)(const char*, const char*, void*);
-typedef void (*ProfilerLabelExit)(ProfilingStack*);
+// Enter should return a pointer that will be given to Exit.
+typedef void* (*ProfilerLabelEnter)(const char* aLabel,
+                                    const char* aDynamicString, void* aSp);
+typedef void (*ProfilerLabelExit)(void* EntryContext);
 
 // Register callbacks that do the entry/exit work involving sProfilingStack.
 MFBT_API void RegisterProfilerLabelEnterExit(ProfilerLabelEnter aEnter,
@@ -46,7 +46,10 @@ class MOZ_RAII AutoProfilerLabel {
 
  private:
   MOZ_DECL_USE_GUARD_OBJECT_NOTIFIER
-  ProfilingStack* mProfilingStack;
+  void* mEntryContext;
+  // Number of RegisterProfilerLabelEnterExit calls, to avoid giving an entry
+  // context from one generation to the next.
+  uint32_t mGeneration;
 };
 
 #endif
diff --git a/mozglue/misc/StackWalk.cpp b/mozglue/misc/StackWalk.cpp
index b5affef165..e028b36473 100644
--- a/mozglue/misc/StackWalk.cpp
+++ b/mozglue/misc/StackWalk.cpp
@@ -813,6 +813,8 @@ MFBT_API bool MozDescribeCodeAddress(void* aPC,
 #    include <cxxabi.h>
 #  endif  // MOZ_DEMANGLE_SYMBOLS
 
+namespace mozilla {
+
 void DemangleSymbol(const char* aSymbol, char* aBuffer, int aBufLen) {
   aBuffer[0] = '\0';
 
@@ -828,6 +830,8 @@ void DemangleSymbol(const char* aSymbol, char* aBuffer, int aBufLen) {
 #  endif  // MOZ_DEMANGLE_SYMBOLS
 }
 
+}  // namespace mozilla
+
 // {x86, ppc} x {Linux, Mac} stackwalking code.
 #  if ((defined(__i386) || defined(PPC) || defined(__ppc__)) && \
        (MOZ_STACKWALK_SUPPORTS_MACOSX || MOZ_STACKWALK_SUPPORTS_LINUX))
diff --git a/mozglue/misc/StackWalk.h b/mozglue/misc/StackWalk.h
index f696e4efcc..53b7a12a0d 100644
--- a/mozglue/misc/StackWalk.h
+++ b/mozglue/misc/StackWalk.h
@@ -166,6 +166,10 @@ MFBT_API void FramePointerStackWalk(MozWalkStackCallback aCallback,
                                     void* aClosure, void** aBp,
                                     void* aStackEnd);
 
+#ifdef XP_LINUX
+MFBT_API void DemangleSymbol(const char* aSymbol, char* aBuffer, int aBufLen);
+#endif
+
 }  // namespace mozilla
 
 #endif
diff --git a/mozglue/tests/TestBaseProfiler.cpp b/mozglue/tests/TestBaseProfiler.cpp
index 917a4ed93f..8401e996cf 100644
--- a/mozglue/tests/TestBaseProfiler.cpp
+++ b/mozglue/tests/TestBaseProfiler.cpp
@@ -6,6 +6,13 @@
 
 #ifdef MOZ_BASE_PROFILER
 
+#  include "BaseProfileJSONWriter.h"
+#  include "BaseProfilerMarkerPayload.h"
+#  include "mozilla/BlocksRingBuffer.h"
+#  include "mozilla/leb128iterator.h"
+#  include "mozilla/ModuloBuffer.h"
+#  include "mozilla/PowerOfTwo.h"
+
 #  include "mozilla/Attributes.h"
 #  include "mozilla/Vector.h"
 
@@ -13,42 +20,20 @@
 #    include <windows.h>
 #    include <mmsystem.h>
 #    include <process.h>
-#  elif defined(__linux__) || (defined(__APPLE__) && defined(__x86_64__))
+#  else
 #    include <time.h>
 #    include <unistd.h>
-#  else
-#    error
 #  endif
 
+#  include <algorithm>
+#  include <atomic>
+#  include <thread>
+#  include <type_traits>
+#  include <utility>
+
 using namespace mozilla;
 
-// Increase the depth, to a maximum (to avoid too-deep recursion).
-static constexpr size_t NextDepth(size_t aDepth) {
-  constexpr size_t MAX_DEPTH = 128;
-  return (aDepth < MAX_DEPTH) ? (aDepth + 1) : aDepth;
-}
-
-// Compute fibonacci the hard way (recursively: `f(n)=f(n-1)+f(n-2)`), and
-// prevent inlining.
-// The template parameter makes each depth be a separate function, to better
-// distinguish them in the profiler output.
-template <size_t DEPTH = 0>
-MOZ_NEVER_INLINE unsigned long long Fibonacci(unsigned long long n) {
-  if (n == 0) {
-    return 0;
-  }
-  if (n == 1) {
-    return 1;
-  }
-  unsigned long long f2 = Fibonacci<NextDepth(DEPTH)>(n - 2);
-  if (DEPTH == 0) {
-    BASE_PROFILER_ADD_MARKER("Half-way through Fibonacci", OTHER);
-  }
-  unsigned long long f1 = Fibonacci<NextDepth(DEPTH)>(n - 1);
-  return f2 + f1;
-}
-
-static void SleepMilli(unsigned aMilliseconds) {
+MOZ_MAYBE_UNUSED static void SleepMilli(unsigned aMilliseconds) {
 #  if defined(_MSC_VER)
   Sleep(aMilliseconds);
 #  else
@@ -67,11 +52,1563 @@ static void SleepMilli(unsigned aMilliseconds) {
 #  endif
 }
 
+void TestPowerOfTwoMask() {
+  printf("TestPowerOfTwoMask...\n");
+
+  static_assert(MakePowerOfTwoMask<uint32_t, 0>().MaskValue() == 0, "");
+  constexpr PowerOfTwoMask<uint32_t> c0 = MakePowerOfTwoMask<uint32_t, 0>();
+  MOZ_RELEASE_ASSERT(c0.MaskValue() == 0);
+
+  static_assert(MakePowerOfTwoMask<uint32_t, 0xFFu>().MaskValue() == 0xFFu, "");
+  constexpr PowerOfTwoMask<uint32_t> cFF =
+      MakePowerOfTwoMask<uint32_t, 0xFFu>();
+  MOZ_RELEASE_ASSERT(cFF.MaskValue() == 0xFFu);
+
+  static_assert(
+      MakePowerOfTwoMask<uint32_t, 0xFFFFFFFFu>().MaskValue() == 0xFFFFFFFFu,
+      "");
+  constexpr PowerOfTwoMask<uint32_t> cFFFFFFFF =
+      MakePowerOfTwoMask<uint32_t, 0xFFFFFFFFu>();
+  MOZ_RELEASE_ASSERT(cFFFFFFFF.MaskValue() == 0xFFFFFFFFu);
+
+  struct TestDataU32 {
+    uint32_t mInput;
+    uint32_t mMask;
+  };
+  // clang-format off
+  TestDataU32 tests[] = {
+    { 0, 0 },
+    { 1, 1 },
+    { 2, 3 },
+    { 3, 3 },
+    { 4, 7 },
+    { 5, 7 },
+    { (1u << 31) - 1, (1u << 31) - 1 },
+    { (1u << 31), uint32_t(-1) },
+    { (1u << 31) + 1, uint32_t(-1) },
+    { uint32_t(-1), uint32_t(-1) }
+  };
+  // clang-format on
+  for (const TestDataU32& test : tests) {
+    PowerOfTwoMask<uint32_t> p2m(test.mInput);
+    MOZ_RELEASE_ASSERT(p2m.MaskValue() == test.mMask);
+    for (const TestDataU32& inner : tests) {
+      if (p2m.MaskValue() != uint32_t(-1)) {
+        MOZ_RELEASE_ASSERT((inner.mInput % p2m) ==
+                           (inner.mInput % (p2m.MaskValue() + 1)));
+      }
+      MOZ_RELEASE_ASSERT((inner.mInput & p2m) == (inner.mInput % p2m));
+      MOZ_RELEASE_ASSERT((p2m & inner.mInput) == (inner.mInput & p2m));
+    }
+  }
+
+  printf("TestPowerOfTwoMask done\n");
+}
+
+void TestPowerOfTwo() {
+  printf("TestPowerOfTwo...\n");
+
+  static_assert(MakePowerOfTwo<uint32_t, 1>().Value() == 1, "");
+  constexpr PowerOfTwo<uint32_t> c1 = MakePowerOfTwo<uint32_t, 1>();
+  MOZ_RELEASE_ASSERT(c1.Value() == 1);
+  static_assert(MakePowerOfTwo<uint32_t, 1>().Mask().MaskValue() == 0, "");
+
+  static_assert(MakePowerOfTwo<uint32_t, 128>().Value() == 128, "");
+  constexpr PowerOfTwo<uint32_t> c128 = MakePowerOfTwo<uint32_t, 128>();
+  MOZ_RELEASE_ASSERT(c128.Value() == 128);
+  static_assert(MakePowerOfTwo<uint32_t, 128>().Mask().MaskValue() == 127, "");
+
+  static_assert(MakePowerOfTwo<uint32_t, 0x80000000u>().Value() == 0x80000000u,
+                "");
+  constexpr PowerOfTwo<uint32_t> cMax = MakePowerOfTwo<uint32_t, 0x80000000u>();
+  MOZ_RELEASE_ASSERT(cMax.Value() == 0x80000000u);
+  static_assert(
+      MakePowerOfTwo<uint32_t, 0x80000000u>().Mask().MaskValue() == 0x7FFFFFFFu,
+      "");
+
+  struct TestDataU32 {
+    uint32_t mInput;
+    uint32_t mValue;
+    uint32_t mMask;
+  };
+  // clang-format off
+  TestDataU32 tests[] = {
+    { 0, 1, 0 },
+    { 1, 1, 0 },
+    { 2, 2, 1 },
+    { 3, 4, 3 },
+    { 4, 4, 3 },
+    { 5, 8, 7 },
+    { (1u << 31) - 1, (1u << 31), (1u << 31) - 1 },
+    { (1u << 31), (1u << 31), (1u << 31) - 1 },
+    { (1u << 31) + 1, (1u << 31), (1u << 31) - 1 },
+    { uint32_t(-1), (1u << 31), (1u << 31) - 1 }
+  };
+  // clang-format on
+  for (const TestDataU32& test : tests) {
+    PowerOfTwo<uint32_t> p2(test.mInput);
+    MOZ_RELEASE_ASSERT(p2.Value() == test.mValue);
+    MOZ_RELEASE_ASSERT(p2.MaskValue() == test.mMask);
+    PowerOfTwoMask<uint32_t> p2m = p2.Mask();
+    MOZ_RELEASE_ASSERT(p2m.MaskValue() == test.mMask);
+    for (const TestDataU32& inner : tests) {
+      MOZ_RELEASE_ASSERT((inner.mInput % p2) == (inner.mInput % p2.Value()));
+    }
+  }
+
+  printf("TestPowerOfTwo done\n");
+}
+
+void TestLEB128() {
+  printf("TestLEB128...\n");
+
+  MOZ_RELEASE_ASSERT(ULEB128MaxSize<uint8_t>() == 2);
+  MOZ_RELEASE_ASSERT(ULEB128MaxSize<uint16_t>() == 3);
+  MOZ_RELEASE_ASSERT(ULEB128MaxSize<uint32_t>() == 5);
+  MOZ_RELEASE_ASSERT(ULEB128MaxSize<uint64_t>() == 10);
+
+  struct TestDataU64 {
+    uint64_t mValue;
+    unsigned mSize;
+    const char* mBytes;
+  };
+  // clang-format off
+  TestDataU64 tests[] = {
+    // Small numbers should keep their normal byte representation.
+    {                  0u,  1, "\0" },
+    {                  1u,  1, "\x01" },
+
+    // 0111 1111 (127, or 0x7F) is the highest number that fits into a single
+    // LEB128 byte. It gets encoded as 0111 1111, note the most significant bit
+    // is off.
+    {               0x7Fu,  1, "\x7F" },
+
+    // Next number: 128, or 0x80.
+    //   Original data representation:  1000 0000
+    //     Broken up into groups of 7:         1  0000000
+    // Padded with 0 (msB) or 1 (lsB):  00000001 10000000
+    //            Byte representation:  0x01     0x80
+    //            Little endian order:  -> 0x80 0x01
+    {               0x80u,  2, "\x80\x01" },
+
+    // Next: 129, or 0x81 (showing that we don't lose low bits.)
+    //   Original data representation:  1000 0001
+    //     Broken up into groups of 7:         1  0000001
+    // Padded with 0 (msB) or 1 (lsB):  00000001 10000001
+    //            Byte representation:  0x01     0x81
+    //            Little endian order:  -> 0x81 0x01
+    {               0x81u,  2, "\x81\x01" },
+
+    // Highest 8-bit number: 255, or 0xFF.
+    //   Original data representation:  1111 1111
+    //     Broken up into groups of 7:         1  1111111
+    // Padded with 0 (msB) or 1 (lsB):  00000001 11111111
+    //            Byte representation:  0x01     0xFF
+    //            Little endian order:  -> 0xFF 0x01
+    {               0xFFu,  2, "\xFF\x01" },
+
+    // Next: 256, or 0x100.
+    //   Original data representation:  1 0000 0000
+    //     Broken up into groups of 7:        10  0000000
+    // Padded with 0 (msB) or 1 (lsB):  00000010 10000000
+    //            Byte representation:  0x10     0x80
+    //            Little endian order:  -> 0x80 0x02
+    {              0x100u,  2, "\x80\x02" },
+
+    // Highest 32-bit number: 0xFFFFFFFF (8 bytes, all bits set).
+    // Original: 1111 1111 1111 1111 1111 1111 1111 1111
+    // Groups:     1111  1111111  1111111  1111111  1111111
+    // Padded: 00001111 11111111 11111111 11111111 11111111
+    // Bytes:  0x0F     0xFF     0xFF     0xFF     0xFF
+    // Little Endian: -> 0xFF 0xFF 0xFF 0xFF 0x0F
+    {         0xFFFFFFFFu,  5, "\xFF\xFF\xFF\xFF\x0F" },
+
+    // Highest 64-bit number: 0xFFFFFFFFFFFFFFFF (16 bytes, all bits set).
+    // 64 bits, that's 9 groups of 7 bits, plus 1 (most significant) bit.
+    { 0xFFFFFFFFFFFFFFFFu, 10, "\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\x01" }
+  };
+  // clang-format on
+
+  for (const TestDataU64& test : tests) {
+    MOZ_RELEASE_ASSERT(ULEB128Size(test.mValue) == test.mSize);
+    // Prepare a buffer that can accomodate the largest-possible LEB128.
+    uint8_t buffer[ULEB128MaxSize<uint64_t>()];
+    // Use a pointer into the buffer as iterator.
+    uint8_t* p = buffer;
+    // And write the LEB128.
+    WriteULEB128(test.mValue, p);
+    // Pointer (iterator) should have advanced just past the expected LEB128
+    // size.
+    MOZ_RELEASE_ASSERT(p == buffer + test.mSize);
+    // Check expected bytes.
+    for (unsigned i = 0; i < test.mSize; ++i) {
+      MOZ_RELEASE_ASSERT(buffer[i] == uint8_t(test.mBytes[i]));
+    }
+    // Move pointer (iterator) back to start of buffer.
+    p = buffer;
+    // And read the LEB128 we wrote above.
+    uint64_t read = ReadULEB128<uint64_t>(p);
+    // Pointer (iterator) should have also advanced just past the expected
+    // LEB128 size.
+    MOZ_RELEASE_ASSERT(p == buffer + test.mSize);
+    // And check the read value.
+    MOZ_RELEASE_ASSERT(read == test.mValue);
+  }
+
+  printf("TestLEB128 done\n");
+}
+
+static void TestModuloBuffer(ModuloBuffer<>& mb, uint32_t MBSize) {
+  using MB = ModuloBuffer<>;
+
+  MOZ_RELEASE_ASSERT(mb.BufferLength().Value() == MBSize);
+
+  // Iterator comparisons.
+  MOZ_RELEASE_ASSERT(mb.ReaderAt(2) == mb.ReaderAt(2));
+  MOZ_RELEASE_ASSERT(mb.ReaderAt(2) != mb.ReaderAt(3));
+  MOZ_RELEASE_ASSERT(mb.ReaderAt(2) < mb.ReaderAt(3));
+  MOZ_RELEASE_ASSERT(mb.ReaderAt(2) <= mb.ReaderAt(2));
+  MOZ_RELEASE_ASSERT(mb.ReaderAt(2) <= mb.ReaderAt(3));
+  MOZ_RELEASE_ASSERT(mb.ReaderAt(3) > mb.ReaderAt(2));
+  MOZ_RELEASE_ASSERT(mb.ReaderAt(2) >= mb.ReaderAt(2));
+  MOZ_RELEASE_ASSERT(mb.ReaderAt(3) >= mb.ReaderAt(2));
+
+  // Iterators indices don't wrap around (even though they may be pointing at
+  // the same location).
+  MOZ_RELEASE_ASSERT(mb.ReaderAt(2) != mb.ReaderAt(MBSize + 2));
+  MOZ_RELEASE_ASSERT(mb.ReaderAt(MBSize + 2) != mb.ReaderAt(2));
+
+  // Dereference.
+  static_assert(std::is_same<decltype(*mb.ReaderAt(0)), const MB::Byte&>::value,
+                "Dereferencing from a reader should return const Byte*");
+  static_assert(std::is_same<decltype(*mb.WriterAt(0)), MB::Byte&>::value,
+                "Dereferencing from a writer should return Byte*");
+  // Contiguous between 0 and MBSize-1.
+  MOZ_RELEASE_ASSERT(&*mb.ReaderAt(MBSize - 1) ==
+                     &*mb.ReaderAt(0) + (MBSize - 1));
+  // Wraps around.
+  MOZ_RELEASE_ASSERT(&*mb.ReaderAt(MBSize) == &*mb.ReaderAt(0));
+  MOZ_RELEASE_ASSERT(&*mb.ReaderAt(MBSize + MBSize - 1) ==
+                     &*mb.ReaderAt(MBSize - 1));
+  MOZ_RELEASE_ASSERT(&*mb.ReaderAt(MBSize + MBSize) == &*mb.ReaderAt(0));
+  // Power of 2 modulo wrapping.
+  MOZ_RELEASE_ASSERT(&*mb.ReaderAt(uint32_t(-1)) == &*mb.ReaderAt(MBSize - 1));
+  MOZ_RELEASE_ASSERT(&*mb.ReaderAt(static_cast<MB::Index>(-1)) ==
+                     &*mb.ReaderAt(MBSize - 1));
+
+  // Arithmetic.
+  MB::Reader arit = mb.ReaderAt(0);
+  MOZ_RELEASE_ASSERT(++arit == mb.ReaderAt(1));
+  MOZ_RELEASE_ASSERT(arit == mb.ReaderAt(1));
+
+  MOZ_RELEASE_ASSERT(--arit == mb.ReaderAt(0));
+  MOZ_RELEASE_ASSERT(arit == mb.ReaderAt(0));
+
+  MOZ_RELEASE_ASSERT(arit++ == mb.ReaderAt(0));
+  MOZ_RELEASE_ASSERT(arit == mb.ReaderAt(1));
+
+  MOZ_RELEASE_ASSERT(arit-- == mb.ReaderAt(1));
+  MOZ_RELEASE_ASSERT(arit == mb.ReaderAt(0));
+
+  MOZ_RELEASE_ASSERT(arit + 3 == mb.ReaderAt(3));
+  MOZ_RELEASE_ASSERT(arit == mb.ReaderAt(0));
+
+  MOZ_RELEASE_ASSERT(4 + arit == mb.ReaderAt(4));
+  MOZ_RELEASE_ASSERT(arit == mb.ReaderAt(0));
+
+  // (Can't have assignments inside asserts, hence the split.)
+  const bool checkPlusEq = ((arit += 3) == mb.ReaderAt(3));
+  MOZ_RELEASE_ASSERT(checkPlusEq);
+  MOZ_RELEASE_ASSERT(arit == mb.ReaderAt(3));
+
+  MOZ_RELEASE_ASSERT((arit - 2) == mb.ReaderAt(1));
+  MOZ_RELEASE_ASSERT(arit == mb.ReaderAt(3));
+
+  const bool checkMinusEq = ((arit -= 2) == mb.ReaderAt(1));
+  MOZ_RELEASE_ASSERT(checkMinusEq);
+  MOZ_RELEASE_ASSERT(arit == mb.ReaderAt(1));
+
+  // Random access.
+  MOZ_RELEASE_ASSERT(&arit[3] == &*(arit + 3));
+  MOZ_RELEASE_ASSERT(arit == mb.ReaderAt(1));
+
+  // Iterator difference.
+  MOZ_RELEASE_ASSERT(mb.ReaderAt(3) - mb.ReaderAt(1) == 2);
+  MOZ_RELEASE_ASSERT(mb.ReaderAt(1) - mb.ReaderAt(3) == MB::Index(-2));
+
+  // Only testing Writer, as Reader is just a subset with no code differences.
+  MB::Writer it = mb.WriterAt(0);
+  MOZ_RELEASE_ASSERT(it.CurrentIndex() == 0);
+
+  // Write two characters at the start.
+  it.WriteObject('x');
+  it.WriteObject('y');
+
+  // Backtrack to read them.
+  it -= 2;
+  // PeekObject should read without moving.
+  MOZ_RELEASE_ASSERT(it.PeekObject<char>() == 'x');
+  MOZ_RELEASE_ASSERT(it.CurrentIndex() == 0);
+  // ReadObject should read and move past the character.
+  MOZ_RELEASE_ASSERT(it.ReadObject<char>() == 'x');
+  MOZ_RELEASE_ASSERT(it.CurrentIndex() == 1);
+  MOZ_RELEASE_ASSERT(it.PeekObject<char>() == 'y');
+  MOZ_RELEASE_ASSERT(it.CurrentIndex() == 1);
+  MOZ_RELEASE_ASSERT(it.ReadObject<char>() == 'y');
+  MOZ_RELEASE_ASSERT(it.CurrentIndex() == 2);
+
+  // Checking that a reader can be created from a writer.
+  MB::Reader it2(it);
+  MOZ_RELEASE_ASSERT(it2.CurrentIndex() == 2);
+  // Or assigned.
+  it2 = it;
+  MOZ_RELEASE_ASSERT(it2.CurrentIndex() == 2);
+
+  // Iterator traits.
+  static_assert(std::is_same<std::iterator_traits<MB::Reader>::difference_type,
+                             MB::Index>::value,
+                "ModuloBuffer::Reader::difference_type should be Index");
+  static_assert(std::is_same<std::iterator_traits<MB::Reader>::value_type,
+                             MB::Byte>::value,
+                "ModuloBuffer::Reader::value_type should be Byte");
+  static_assert(std::is_same<std::iterator_traits<MB::Reader>::pointer,
+                             const MB::Byte*>::value,
+                "ModuloBuffer::Reader::pointer should be const Byte*");
+  static_assert(std::is_same<std::iterator_traits<MB::Reader>::reference,
+                             const MB::Byte&>::value,
+                "ModuloBuffer::Reader::reference should be const Byte&");
+  static_assert(std::is_base_of<
+                    std::input_iterator_tag,
+                    std::iterator_traits<MB::Reader>::iterator_category>::value,
+                "ModuloBuffer::Reader::iterator_category should be derived "
+                "from input_iterator_tag");
+  static_assert(std::is_base_of<
+                    std::forward_iterator_tag,
+                    std::iterator_traits<MB::Reader>::iterator_category>::value,
+                "ModuloBuffer::Reader::iterator_category should be derived "
+                "from forward_iterator_tag");
+  static_assert(std::is_base_of<
+                    std::bidirectional_iterator_tag,
+                    std::iterator_traits<MB::Reader>::iterator_category>::value,
+                "ModuloBuffer::Reader::iterator_category should be derived "
+                "from bidirectional_iterator_tag");
+  static_assert(
+      std::is_same<std::iterator_traits<MB::Reader>::iterator_category,
+                   std::random_access_iterator_tag>::value,
+      "ModuloBuffer::Reader::iterator_category should be "
+      "random_access_iterator_tag");
+
+  // Use as input iterator by std::string constructor (which is only considered
+  // with proper input iterators.)
+  std::string s(mb.ReaderAt(0), mb.ReaderAt(2));
+  MOZ_RELEASE_ASSERT(s == "xy");
+
+  // Write 4-byte number at index 2.
+  it.WriteObject(int32_t(123));
+  MOZ_RELEASE_ASSERT(it.CurrentIndex() == 6);
+  // And another, which should now wrap around (but index continues on.)
+  it.WriteObject(int32_t(456));
+  MOZ_RELEASE_ASSERT(it.CurrentIndex() == MBSize + 2);
+  // Even though index==MBSize+2, we can read the object we wrote at 2.
+  MOZ_RELEASE_ASSERT(it.ReadObject<int32_t>() == 123);
+  MOZ_RELEASE_ASSERT(it.CurrentIndex() == MBSize + 6);
+  // And similarly, index MBSize+6 points at the same location as index 6.
+  MOZ_RELEASE_ASSERT(it.ReadObject<int32_t>() == 456);
+  MOZ_RELEASE_ASSERT(it.CurrentIndex() == MBSize + MBSize + 2);
+}
+
+void TestModuloBuffer() {
+  printf("TestModuloBuffer...\n");
+
+  // Testing ModuloBuffer with default template arguments.
+  using MB = ModuloBuffer<>;
+
+  // Only 8-byte buffers, to easily test wrap-around.
+  constexpr uint32_t MBSize = 8;
+
+  // MB with self-allocated heap buffer.
+  MB mbByLength(MakePowerOfTwo32<MBSize>());
+  TestModuloBuffer(mbByLength, MBSize);
+
+  // MB taking ownership of a provided UniquePtr to a buffer.
+  auto uniqueBuffer = MakeUnique<uint8_t[]>(MBSize);
+  MB mbByUniquePtr(MakeUnique<uint8_t[]>(MBSize), MakePowerOfTwo32<MBSize>());
+  TestModuloBuffer(mbByUniquePtr, MBSize);
+
+  // MB using part of a buffer on the stack. The buffer is three times the
+  // required size: The middle third is where ModuloBuffer will work, the first
+  // and last thirds are only used to later verify that ModuloBuffer didn't go
+  // out of its bounds.
+  uint8_t buffer[MBSize * 3];
+  // Pre-fill the buffer with a known pattern, so we can later see what changed.
+  for (size_t i = 0; i < MBSize * 3; ++i) {
+    buffer[i] = uint8_t('A' + i);
+  }
+  MB mbByBuffer(&buffer[MBSize], MakePowerOfTwo32<MBSize>());
+  TestModuloBuffer(mbByBuffer, MBSize);
+
+  // Check that only the provided stack-based sub-buffer was modified.
+  uint32_t changed = 0;
+  for (size_t i = MBSize; i < MBSize * 2; ++i) {
+    changed += (buffer[i] == uint8_t('A' + i)) ? 0 : 1;
+  }
+  // Expect at least 75% changes.
+  MOZ_RELEASE_ASSERT(changed >= MBSize * 6 / 8);
+
+  // Everything around the sub-buffer should be unchanged.
+  for (size_t i = 0; i < MBSize; ++i) {
+    MOZ_RELEASE_ASSERT(buffer[i] == uint8_t('A' + i));
+  }
+  for (size_t i = MBSize * 2; i < MBSize * 3; ++i) {
+    MOZ_RELEASE_ASSERT(buffer[i] == uint8_t('A' + i));
+  }
+
+  // Check that move-construction is allowed. This verifies that we do not
+  // crash from a double free, when `mbByBuffer` and `mbByStolenBuffer` are both
+  // destroyed at the end of this function.
+  MB mbByStolenBuffer = std::move(mbByBuffer);
+  TestModuloBuffer(mbByStolenBuffer, MBSize);
+
+  // Check that only the provided stack-based sub-buffer was modified.
+  changed = 0;
+  for (size_t i = MBSize; i < MBSize * 2; ++i) {
+    changed += (buffer[i] == uint8_t('A' + i)) ? 0 : 1;
+  }
+  // Expect at least 75% changes.
+  MOZ_RELEASE_ASSERT(changed >= MBSize * 6 / 8);
+
+  // Everything around the sub-buffer should be unchanged.
+  for (size_t i = 0; i < MBSize; ++i) {
+    MOZ_RELEASE_ASSERT(buffer[i] == uint8_t('A' + i));
+  }
+  for (size_t i = MBSize * 2; i < MBSize * 3; ++i) {
+    MOZ_RELEASE_ASSERT(buffer[i] == uint8_t('A' + i));
+  }
+
+  // This test function does a `ReadInto` as directed, and checks that the
+  // result is the same as if the copy had been done manually byte-by-byte.
+  // `TestReadInto(3, 7, 2)` copies from index 3 to index 7, 2 bytes long.
+  // Return the output string (from `ReadInto`) for external checks.
+  auto TestReadInto = [](MB::Index aReadFrom, MB::Index aWriteTo,
+                         MB::Length aBytes) {
+    constexpr uint32_t TRISize = 16;
+
+    // Prepare an input buffer, all different elements.
+    uint8_t input[TRISize + 1] = "ABCDEFGHIJKLMNOP";
+    const MB mbInput(input, MakePowerOfTwo32<TRISize>());
+
+    // Prepare an output buffer, different from input.
+    uint8_t output[TRISize + 1] = "abcdefghijklmnop";
+    MB mbOutput(output, MakePowerOfTwo32<TRISize>());
+
+    // Run ReadInto.
+    auto writer = mbOutput.WriterAt(aWriteTo);
+    mbInput.ReaderAt(aReadFrom).ReadInto(writer, aBytes);
+
+    // Do the same operation manually.
+    uint8_t outputCheck[TRISize + 1] = "abcdefghijklmnop";
+    MB mbOutputCheck(outputCheck, MakePowerOfTwo32<TRISize>());
+    auto readerCheck = mbInput.ReaderAt(aReadFrom);
+    auto writerCheck = mbOutputCheck.WriterAt(aWriteTo);
+    for (MB::Length i = 0; i < aBytes; ++i) {
+      *writerCheck++ = *readerCheck++;
+    }
+
+    // Compare the two outputs.
+    for (uint32_t i = 0; i < TRISize; ++i) {
+#  ifdef TEST_MODULOBUFFER_FAILURE_DEBUG
+      // Only used when debugging failures.
+      if (output[i] != outputCheck[i]) {
+        printf(
+            "*** from=%u to=%u bytes=%u i=%u\ninput:  '%s'\noutput: "
+            "'%s'\ncheck:  '%s'\n",
+            unsigned(aReadFrom), unsigned(aWriteTo), unsigned(aBytes),
+            unsigned(i), input, output, outputCheck);
+      }
+#  endif
+      MOZ_RELEASE_ASSERT(output[i] == outputCheck[i]);
+    }
+
+#  ifdef TEST_MODULOBUFFER_HELPER
+    // Only used when adding more tests.
+    printf("*** from=%u to=%u bytes=%u output: %s\n", unsigned(aReadFrom),
+           unsigned(aWriteTo), unsigned(aBytes), output);
+#  endif
+
+    return std::string(reinterpret_cast<const char*>(output));
+  };
+
+  // A few manual checks:
+  constexpr uint32_t TRISize = 16;
+  MOZ_RELEASE_ASSERT(TestReadInto(0, 0, 0) == "abcdefghijklmnop");
+  MOZ_RELEASE_ASSERT(TestReadInto(0, 0, TRISize) == "ABCDEFGHIJKLMNOP");
+  MOZ_RELEASE_ASSERT(TestReadInto(0, 5, TRISize) == "LMNOPABCDEFGHIJK");
+  MOZ_RELEASE_ASSERT(TestReadInto(5, 0, TRISize) == "FGHIJKLMNOPABCDE");
+
+  // Test everything! (16^3 = 4096, not too much.)
+  for (MB::Index r = 0; r < TRISize; ++r) {
+    for (MB::Index w = 0; w < TRISize; ++w) {
+      for (MB::Length len = 0; len < TRISize; ++len) {
+        TestReadInto(r, w, len);
+      }
+    }
+  }
+
+  printf("TestModuloBuffer done\n");
+}
+
+// Backdoor into value of BlockIndex, only for unit-testing.
+static uint64_t ExtractBlockIndex(const BlocksRingBuffer::BlockIndex bi) {
+  uint64_t index;
+  static_assert(sizeof(bi) == sizeof(index),
+                "BlockIndex expected to only contain a uint64_t");
+  memcpy(&index, &bi, sizeof(index));
+  return index;
+};
+
+void TestBlocksRingBufferAPI() {
+  printf("TestBlocksRingBufferAPI...\n");
+
+  // Create a 16-byte buffer, enough to store up to 3 entries (1 byte size + 4
+  // bytes uint64_t).
+  constexpr uint32_t MBSize = 16;
+  uint8_t buffer[MBSize * 3];
+  for (size_t i = 0; i < MBSize * 3; ++i) {
+    buffer[i] = uint8_t('A' + i);
+  }
+
+  // Start a temporary block to constrain buffer lifetime.
+  {
+    BlocksRingBuffer rb(BlocksRingBuffer::ThreadSafety::WithMutex,
+                        &buffer[MBSize], MakePowerOfTwo32<MBSize>());
+
+#  define VERIFY_START_END_PUSHED_CLEARED(aStart, aEnd, aPushed, aCleared)  \
+    {                                                                       \
+      BlocksRingBuffer::State state = rb.GetState();                        \
+      MOZ_RELEASE_ASSERT(ExtractBlockIndex(state.mRangeStart) == (aStart)); \
+      MOZ_RELEASE_ASSERT(ExtractBlockIndex(state.mRangeEnd) == (aEnd));     \
+      MOZ_RELEASE_ASSERT(state.mPushedBlockCount == (aPushed));             \
+      MOZ_RELEASE_ASSERT(state.mClearedBlockCount == (aCleared));           \
+    }
+
+    // All entries will contain one 32-bit number. The resulting blocks will
+    // have the following structure:
+    // - 1 byte for the LEB128 size of 4
+    // - 4 bytes for the number.
+    // E.g., if we have entries with `123` and `456`:
+    //   .-- Index 0 reserved for empty BlockIndex, nothing there.
+    //   | .-- first readable block at index 1
+    //   | |.-- first block at index 1
+    //   | ||.-- 1 byte for the entry size, which is `4` (32 bits)
+    //   | |||  .-- entry starts at index 2, contains 32-bit int
+    //   | |||  |             .-- entry and block finish *after* index 5 (so 6)
+    //   | |||  |             | .-- second block starts at index 6
+    //   | |||  |             | |         etc.
+    //   | |||  |             | |                  .-- End readable blocks: 11
+    //   v vvv  v             v V                  v
+    //   0   1   2   3   4   5   6   7   8   9  10  11  12  13  14  15
+    //   - S[4 |   int(123)   ] [4 |   int(456)   ]E
+
+    // Empty buffer to start with.
+    // Start&end indices still at 1 (0 is reserved for the default BlockIndex{}
+    // that cannot point at a valid entry), nothing cleared.
+    VERIFY_START_END_PUSHED_CLEARED(1, 1, 0, 0);
+
+    // Default BlockIndex.
+    BlocksRingBuffer::BlockIndex bi0;
+    if (bi0) {
+      MOZ_RELEASE_ASSERT(false, "if (BlockIndex{}) should fail test");
+    }
+    if (!bi0) {
+    } else {
+      MOZ_RELEASE_ASSERT(false, "if (!BlockIndex{}) should succeed test");
+    }
+    MOZ_RELEASE_ASSERT(!bi0);
+    MOZ_RELEASE_ASSERT(bi0 == bi0);
+    MOZ_RELEASE_ASSERT(bi0 <= bi0);
+    MOZ_RELEASE_ASSERT(bi0 >= bi0);
+    MOZ_RELEASE_ASSERT(!(bi0 != bi0));
+    MOZ_RELEASE_ASSERT(!(bi0 < bi0));
+    MOZ_RELEASE_ASSERT(!(bi0 > bi0));
+
+    // Default BlockIndex can be used, but returns no valid entry.
+    rb.ReadAt(bi0, [](Maybe<BlocksRingBuffer::EntryReader>&& aMaybeReader) {
+      MOZ_RELEASE_ASSERT(aMaybeReader.isNothing());
+    });
+
+    // Push `1` directly.
+    MOZ_RELEASE_ASSERT(ExtractBlockIndex(rb.PutObject(uint32_t(1))) == 1);
+    //   0   1   2   3   4   5   6   7   8   9  10  11  12  13  14  15
+    //   - S[4 |    int(1)    ]E
+    VERIFY_START_END_PUSHED_CLEARED(1, 6, 1, 0);
+
+    // Push `2` through ReserveAndPut, check output BlockIndex.
+    auto bi2 = rb.ReserveAndPut([]() { return sizeof(uint32_t); },
+                                [](BlocksRingBuffer::EntryWriter* aEW) {
+                                  MOZ_RELEASE_ASSERT(!!aEW);
+                                  aEW->WriteObject(uint32_t(2));
+                                  return aEW->CurrentBlockIndex();
+                                });
+    static_assert(
+        std::is_same<decltype(bi2), BlocksRingBuffer::BlockIndex>::value,
+        "All index-returning functions should return a "
+        "BlocksRingBuffer::BlockIndex");
+    MOZ_RELEASE_ASSERT(ExtractBlockIndex(bi2) == 6);
+    //   0   1   2   3   4   5   6   7   8   9  10  11  12  13  14  15
+    //   - S[4 |    int(1)    ] [4 |    int(2)    ]E
+    VERIFY_START_END_PUSHED_CLEARED(1, 11, 2, 0);
+
+    // Check single entry at bi2, store next block index.
+    auto bi2Next =
+        rb.ReadAt(bi2, [](Maybe<BlocksRingBuffer::EntryReader>&& aMaybeReader) {
+          MOZ_RELEASE_ASSERT(aMaybeReader.isSome());
+          MOZ_RELEASE_ASSERT(aMaybeReader->ReadObject<uint32_t>() == 2);
+          MOZ_RELEASE_ASSERT(
+              aMaybeReader->GetEntryAt(aMaybeReader->NextBlockIndex())
+                  .isNothing());
+          return aMaybeReader->NextBlockIndex();
+        });
+    // bi2Next is at the end, nothing to read.
+    rb.ReadAt(bi2Next, [](Maybe<BlocksRingBuffer::EntryReader>&& aMaybeReader) {
+      MOZ_RELEASE_ASSERT(aMaybeReader.isNothing());
+    });
+
+    // BlockIndex tests.
+    if (bi2) {
+    } else {
+      MOZ_RELEASE_ASSERT(false,
+                         "if (non-default-BlockIndex) should succeed test");
+    }
+    if (!bi2) {
+      MOZ_RELEASE_ASSERT(false,
+                         "if (!non-default-BlockIndex) should fail test");
+    }
+
+    MOZ_RELEASE_ASSERT(!!bi2);
+    MOZ_RELEASE_ASSERT(bi2 == bi2);
+    MOZ_RELEASE_ASSERT(bi2 <= bi2);
+    MOZ_RELEASE_ASSERT(bi2 >= bi2);
+    MOZ_RELEASE_ASSERT(!(bi2 != bi2));
+    MOZ_RELEASE_ASSERT(!(bi2 < bi2));
+    MOZ_RELEASE_ASSERT(!(bi2 > bi2));
+
+    MOZ_RELEASE_ASSERT(bi0 != bi2);
+    MOZ_RELEASE_ASSERT(bi0 < bi2);
+    MOZ_RELEASE_ASSERT(bi0 <= bi2);
+    MOZ_RELEASE_ASSERT(!(bi0 == bi2));
+    MOZ_RELEASE_ASSERT(!(bi0 > bi2));
+    MOZ_RELEASE_ASSERT(!(bi0 >= bi2));
+
+    MOZ_RELEASE_ASSERT(bi2 != bi0);
+    MOZ_RELEASE_ASSERT(bi2 > bi0);
+    MOZ_RELEASE_ASSERT(bi2 >= bi0);
+    MOZ_RELEASE_ASSERT(!(bi2 == bi0));
+    MOZ_RELEASE_ASSERT(!(bi2 < bi0));
+    MOZ_RELEASE_ASSERT(!(bi2 <= bi0));
+
+    MOZ_RELEASE_ASSERT(bi2 != bi2Next);
+    MOZ_RELEASE_ASSERT(bi2 < bi2Next);
+    MOZ_RELEASE_ASSERT(bi2 <= bi2Next);
+    MOZ_RELEASE_ASSERT(!(bi2 == bi2Next));
+    MOZ_RELEASE_ASSERT(!(bi2 > bi2Next));
+    MOZ_RELEASE_ASSERT(!(bi2 >= bi2Next));
+
+    MOZ_RELEASE_ASSERT(bi2Next != bi2);
+    MOZ_RELEASE_ASSERT(bi2Next > bi2);
+    MOZ_RELEASE_ASSERT(bi2Next >= bi2);
+    MOZ_RELEASE_ASSERT(!(bi2Next == bi2));
+    MOZ_RELEASE_ASSERT(!(bi2Next < bi2));
+    MOZ_RELEASE_ASSERT(!(bi2Next <= bi2));
+
+    // Push `3` through Put, check writer output
+    // is returned to the initial caller.
+    auto put3 =
+        rb.Put(sizeof(uint32_t), [&](BlocksRingBuffer::EntryWriter* aEW) {
+          MOZ_RELEASE_ASSERT(!!aEW);
+          aEW->WriteObject(uint32_t(3));
+          return float(ExtractBlockIndex(aEW->CurrentBlockIndex()));
+        });
+    static_assert(std::is_same<decltype(put3), float>::value,
+                  "Expect float as returned by callback.");
+    MOZ_RELEASE_ASSERT(put3 == 11.0);
+    //   0   1   2   3   4   5   6   7   8   9  10  11  12  13  14  15 (16)
+    //   - S[4 |    int(1)    ] [4 |    int(2)    ] [4 |    int(3)    ]E
+    VERIFY_START_END_PUSHED_CLEARED(1, 16, 3, 0);
+
+    // Re-Read single entry at bi2, should now have a next entry.
+    rb.ReadAt(bi2, [&](Maybe<BlocksRingBuffer::EntryReader>&& aMaybeReader) {
+      MOZ_RELEASE_ASSERT(aMaybeReader.isSome());
+      MOZ_RELEASE_ASSERT(aMaybeReader->ReadObject<uint32_t>() == 2);
+      MOZ_RELEASE_ASSERT(aMaybeReader->NextBlockIndex() == bi2Next);
+      MOZ_RELEASE_ASSERT(aMaybeReader->GetNextEntry().isSome());
+      MOZ_RELEASE_ASSERT(
+          aMaybeReader->GetEntryAt(aMaybeReader->NextBlockIndex()).isSome());
+      MOZ_RELEASE_ASSERT(
+          aMaybeReader->GetNextEntry()->CurrentBlockIndex() ==
+          aMaybeReader->GetEntryAt(aMaybeReader->NextBlockIndex())
+              ->CurrentBlockIndex());
+      MOZ_RELEASE_ASSERT(
+          aMaybeReader->GetEntryAt(aMaybeReader->NextBlockIndex())
+              ->ReadObject<uint32_t>() == 3);
+    });
+
+    // Check that we have `1` to `3`.
+    uint32_t count = 0;
+    rb.ReadEach([&](BlocksRingBuffer::EntryReader& aReader) {
+      MOZ_RELEASE_ASSERT(aReader.ReadObject<uint32_t>() == ++count);
+    });
+    MOZ_RELEASE_ASSERT(count == 3);
+
+    // Push `4`, store its BlockIndex for later.
+    // This will wrap around, and clear the first entry.
+    BlocksRingBuffer::BlockIndex bi4 = rb.PutObject(uint32_t(4));
+    // Before:
+    //   0   1   2   3   4   5   6   7   8   9  10  11  12  13  14  15 (16)
+    //   - S[4 |    int(1)    ] [4 |    int(2)    ] [4 |    int(3)    ]E
+    // 1. First entry cleared:
+    //   0   1   2   3   4   5   6   7   8   9  10  11  12  13  14  15 (16)
+    //   -   ?   ?   ?   ?   ? S[4 |    int(2)    ] [4 |    int(3)    ]E
+    // 2. New entry starts at 15 and wraps around: (shown on separate line)
+    //   0   1   2   3   4   5   6   7   8   9  10  11  12  13  14  15 (16)
+    //   -   ?   ?   ?   ?   ? S[4 |    int(2)    ] [4 |    int(3)    ]
+    //  16  17  18  19  20  21  ...
+    //  [4 |    int(4)    ]E
+    // (collapsed)
+    //  16  17  18  19  20  21   6   7   8   9  10  11  12  13  14  15 (16)
+    //  [4 |    int(4)    ]E ? S[4 |    int(2)    ] [4 |    int(3)    ]
+    VERIFY_START_END_PUSHED_CLEARED(6, 21, 4, 1);
+
+    // Check that we have `2` to `4`.
+    count = 1;
+    rb.ReadEach([&](BlocksRingBuffer::EntryReader& aReader) {
+      MOZ_RELEASE_ASSERT(aReader.ReadObject<uint32_t>() == ++count);
+    });
+    MOZ_RELEASE_ASSERT(count == 4);
+
+    // Push 5 through Put, no returns.
+    // This will clear the second entry.
+    // Check that the EntryWriter can access bi4 but not bi2.
+    auto bi5_6 =
+        rb.Put(sizeof(uint32_t), [&](BlocksRingBuffer::EntryWriter* aEW) {
+          MOZ_RELEASE_ASSERT(!!aEW);
+          aEW->WriteObject(uint32_t(5));
+          MOZ_RELEASE_ASSERT(aEW->GetEntryAt(bi2).isNothing());
+          MOZ_RELEASE_ASSERT(aEW->GetEntryAt(bi4).isSome());
+          MOZ_RELEASE_ASSERT(aEW->GetEntryAt(bi4)->CurrentBlockIndex() == bi4);
+          MOZ_RELEASE_ASSERT(aEW->GetEntryAt(bi4)->ReadObject<uint32_t>() == 4);
+          return std::make_pair(aEW->CurrentBlockIndex(), aEW->BlockEndIndex());
+        });
+    auto& bi5 = bi5_6.first;
+    auto& bi6 = bi5_6.second;
+    //  16  17  18  19  20  21  22  23  24  25  26  11  12  13  14  15 (16)
+    //  [4 |    int(4)    ] [4 |    int(5)    ]E ? S[4 |    int(3)    ]
+    VERIFY_START_END_PUSHED_CLEARED(11, 26, 5, 2);
+
+    // Read single entry at bi2, should now gracefully fail.
+    rb.ReadAt(bi2, [](Maybe<BlocksRingBuffer::EntryReader>&& aMaybeReader) {
+      MOZ_RELEASE_ASSERT(aMaybeReader.isNothing());
+    });
+
+    // Read single entry at bi5.
+    rb.ReadAt(bi5, [](Maybe<BlocksRingBuffer::EntryReader>&& aMaybeReader) {
+      MOZ_RELEASE_ASSERT(aMaybeReader.isSome());
+      MOZ_RELEASE_ASSERT(aMaybeReader->ReadObject<uint32_t>() == 5);
+      MOZ_RELEASE_ASSERT(
+          aMaybeReader->GetEntryAt(aMaybeReader->NextBlockIndex()).isNothing());
+    });
+
+    rb.Read([&](BlocksRingBuffer::Reader* aReader) {
+      MOZ_RELEASE_ASSERT(!!aReader);
+      // begin() and end() should be at the range edges (verified above).
+      MOZ_RELEASE_ASSERT(
+          ExtractBlockIndex(aReader->begin().CurrentBlockIndex()) == 11);
+      MOZ_RELEASE_ASSERT(
+          ExtractBlockIndex(aReader->end().CurrentBlockIndex()) == 26);
+      // Null BlockIndex clamped to the beginning.
+      MOZ_RELEASE_ASSERT(aReader->At(bi0) == aReader->begin());
+      // Cleared block index clamped to the beginning.
+      MOZ_RELEASE_ASSERT(aReader->At(bi2) == aReader->begin());
+      // At(begin) same as begin().
+      MOZ_RELEASE_ASSERT(aReader->At(aReader->begin().CurrentBlockIndex()) ==
+                         aReader->begin());
+      // bi5 at expected position.
+      MOZ_RELEASE_ASSERT(
+          ExtractBlockIndex(aReader->At(bi5).CurrentBlockIndex()) == 21);
+      // bi6 at expected position at the end.
+      MOZ_RELEASE_ASSERT(aReader->At(bi6) == aReader->end());
+      // At(end) same as end().
+      MOZ_RELEASE_ASSERT(aReader->At(aReader->end().CurrentBlockIndex()) ==
+                         aReader->end());
+    });
+
+    // Check that we have `3` to `5`.
+    count = 2;
+    rb.ReadEach([&](BlocksRingBuffer::EntryReader& aReader) {
+      MOZ_RELEASE_ASSERT(aReader.ReadObject<uint32_t>() == ++count);
+    });
+    MOZ_RELEASE_ASSERT(count == 5);
+
+    // Clear everything before `4`, this should clear `3`.
+    rb.ClearBefore(bi4);
+    //  16  17  18  19  20  21  22  23  24  25  26  11  12  13  14  15
+    // S[4 |    int(4)    ] [4 |    int(5)    ]E ?   ?   ?   ?   ?   ?
+    VERIFY_START_END_PUSHED_CLEARED(16, 26, 5, 3);
+
+    // Check that we have `4` to `5`.
+    count = 3;
+    rb.ReadEach([&](BlocksRingBuffer::EntryReader& aReader) {
+      MOZ_RELEASE_ASSERT(aReader.ReadObject<uint32_t>() == ++count);
+    });
+    MOZ_RELEASE_ASSERT(count == 5);
+
+    // Clear everything before `4` again, nothing to clear.
+    rb.ClearBefore(bi4);
+    VERIFY_START_END_PUSHED_CLEARED(16, 26, 5, 3);
+
+    // Clear everything, this should clear `4` and `5`, and bring the start
+    // index where the end index currently is.
+    rb.ClearBefore(bi6);
+    //  16  17  18  19  20  21  22  23  24  25  26  11  12  13  14  15
+    //   ?   ?   ?   ?   ?   ?   ?   ?   ?   ? SE?   ?   ?   ?   ?   ?
+    VERIFY_START_END_PUSHED_CLEARED(26, 26, 5, 5);
+
+    // Check that we have nothing to read.
+    rb.ReadEach([&](auto&&) { MOZ_RELEASE_ASSERT(false); });
+
+    // Read single entry at bi5, should now gracefully fail.
+    rb.ReadAt(bi5, [](Maybe<BlocksRingBuffer::EntryReader>&& aMaybeReader) {
+      MOZ_RELEASE_ASSERT(aMaybeReader.isNothing());
+    });
+
+    // Clear everything before now-cleared `4`, nothing to clear.
+    rb.ClearBefore(bi4);
+    VERIFY_START_END_PUSHED_CLEARED(26, 26, 5, 5);
+
+    // Push `6` directly.
+    MOZ_RELEASE_ASSERT(rb.PutObject(uint32_t(6)) == bi6);
+    //  16  17  18  19  20  21  22  23  24  25  26  27  28  29  30  31
+    //   ?   ?   ?   ?   ?   ?   ?   ?   ?   ? S[4 |    int(6)    ]E ?
+    VERIFY_START_END_PUSHED_CLEARED(26, 31, 6, 5);
+
+    {
+      // Create a 2nd buffer and fill it with `7` and `8`.
+      uint8_t buffer2[MBSize];
+      BlocksRingBuffer rb2(BlocksRingBuffer::ThreadSafety::WithoutMutex,
+                           buffer2, MakePowerOfTwo32<MBSize>());
+      rb2.PutObject(uint32_t(7));
+      rb2.PutObject(uint32_t(8));
+      // Main buffer shouldn't have changed.
+      VERIFY_START_END_PUSHED_CLEARED(26, 31, 6, 5);
+
+      // Append contents of rb2 to rb, this should end up being the same as
+      // pushing the two numbers.
+      rb.AppendContents(rb2);
+      //  32  33  34  35  36  37  38  39  40  41  26  27  28  29  30  31
+      //      int(7)    ] [4 |    int(8)    ]E ? S[4 |    int(6)    ] [4 |
+      VERIFY_START_END_PUSHED_CLEARED(26, 41, 8, 5);
+
+      // Append contents of rb2 to rb again, to verify that rb2 was not modified
+      // above. This should clear `6` and the first `7`.
+      rb.AppendContents(rb2);
+      //  48  49  50  51  36  37  38  39  40  41  42  43  44  45  46  47
+      //  int(8)    ]E ? S[4 |    int(8)    ] [4 |    int(7)    ] [4 |
+      VERIFY_START_END_PUSHED_CLEARED(36, 51, 10, 7);
+
+      // End of block where rb2 lives, to verify that it is not needed anymore
+      // for its copied values to survive in rb.
+    }
+    VERIFY_START_END_PUSHED_CLEARED(36, 51, 10, 7);
+
+    // bi6 should now have been cleared.
+    rb.ReadAt(bi6, [](Maybe<BlocksRingBuffer::EntryReader>&& aMaybeReader) {
+      MOZ_RELEASE_ASSERT(aMaybeReader.isNothing());
+    });
+
+    // Check that we have `8`, `7`, `8`.
+    count = 0;
+    uint32_t expected[3] = {8, 7, 8};
+    rb.ReadEach([&](BlocksRingBuffer::EntryReader& aReader) {
+      MOZ_RELEASE_ASSERT(count < 3);
+      MOZ_RELEASE_ASSERT(aReader.ReadObject<uint32_t>() == expected[count++]);
+    });
+    MOZ_RELEASE_ASSERT(count == 3);
+
+    // End of block where rb lives, BlocksRingBuffer destructor should call
+    // entry destructor for remaining entries.
+  }
+
+  // Check that only the provided stack-based sub-buffer was modified.
+  uint32_t changed = 0;
+  for (size_t i = MBSize; i < MBSize * 2; ++i) {
+    changed += (buffer[i] == uint8_t('A' + i)) ? 0 : 1;
+  }
+  // Expect at least 75% changes.
+  MOZ_RELEASE_ASSERT(changed >= MBSize * 6 / 8);
+
+  // Everything around the sub-buffer should be unchanged.
+  for (size_t i = 0; i < MBSize; ++i) {
+    MOZ_RELEASE_ASSERT(buffer[i] == uint8_t('A' + i));
+  }
+  for (size_t i = MBSize * 2; i < MBSize * 3; ++i) {
+    MOZ_RELEASE_ASSERT(buffer[i] == uint8_t('A' + i));
+  }
+
+  printf("TestBlocksRingBufferAPI done\n");
+}
+
+void TestBlocksRingBufferUnderlyingBufferChanges() {
+  printf("TestBlocksRingBufferUnderlyingBufferChanges...\n");
+
+  // Out-of-session BlocksRingBuffer to start with.
+  BlocksRingBuffer rb(BlocksRingBuffer::ThreadSafety::WithMutex);
+
+  // Block index to read at. Initially "null", but may be changed below.
+  BlocksRingBuffer::BlockIndex bi;
+
+  // Test all rb APIs when rb is out-of-session and therefore doesn't have an
+  // underlying buffer.
+  auto testOutOfSession = [&]() {
+    MOZ_RELEASE_ASSERT(rb.BufferLength().isNothing());
+    BlocksRingBuffer::State state = rb.GetState();
+    // When out-of-session, range start and ends are the same, and there are no
+    // pushed&cleared blocks.
+    MOZ_RELEASE_ASSERT(state.mRangeStart == state.mRangeEnd);
+    MOZ_RELEASE_ASSERT(state.mPushedBlockCount == 0);
+    MOZ_RELEASE_ASSERT(state.mClearedBlockCount == 0);
+    // `Put()` functions run the callback with `Nothing`.
+    int32_t ran = 0;
+    rb.Put(1, [&](BlocksRingBuffer::EntryWriter* aMaybeEntryWriter) {
+      MOZ_RELEASE_ASSERT(!aMaybeEntryWriter);
+      ++ran;
+    });
+    MOZ_RELEASE_ASSERT(ran == 1);
+    // `PutFrom` won't do anything, and returns the null BlockIndex.
+    MOZ_RELEASE_ASSERT(rb.PutFrom(&ran, sizeof(ran)) ==
+                       BlocksRingBuffer::BlockIndex{});
+    MOZ_RELEASE_ASSERT(rb.PutObject(ran) == BlocksRingBuffer::BlockIndex{});
+    // `Read()` functions run the callback with `Nothing`.
+    ran = 0;
+    rb.Read([&](BlocksRingBuffer::Reader* aReader) {
+      MOZ_RELEASE_ASSERT(!aReader);
+      ++ran;
+    });
+    MOZ_RELEASE_ASSERT(ran == 1);
+    ran = 0;
+    rb.ReadAt(BlocksRingBuffer::BlockIndex{},
+              [&](Maybe<BlocksRingBuffer::EntryReader>&& aMaybeEntryReader) {
+                MOZ_RELEASE_ASSERT(aMaybeEntryReader.isNothing());
+                ++ran;
+              });
+    MOZ_RELEASE_ASSERT(ran == 1);
+    ran = 0;
+    rb.ReadAt(bi,
+              [&](Maybe<BlocksRingBuffer::EntryReader>&& aMaybeEntryReader) {
+                MOZ_RELEASE_ASSERT(aMaybeEntryReader.isNothing());
+                ++ran;
+              });
+    MOZ_RELEASE_ASSERT(ran == 1);
+    // `ReadEach` shouldn't run the callback (nothing to read).
+    rb.ReadEach([](auto&&) { MOZ_RELEASE_ASSERT(false); });
+  };
+
+  // As `testOutOfSession()` attempts to modify the buffer, we run it twice to
+  // make sure one run doesn't influence the next one.
+  testOutOfSession();
+  testOutOfSession();
+
+  rb.ClearBefore(bi);
+  testOutOfSession();
+  testOutOfSession();
+
+  rb.Clear();
+  testOutOfSession();
+  testOutOfSession();
+
+  rb.Reset();
+  testOutOfSession();
+  testOutOfSession();
+
+  constexpr uint32_t MBSize = 32;
+
+  rb.Set(MakePowerOfTwo<BlocksRingBuffer::Length, MBSize>());
+
+  constexpr bool EMPTY = true;
+  constexpr bool NOT_EMPTY = false;
+  // Test all rb APIs when rb has an underlying buffer.
+  auto testInSession = [&](bool aExpectEmpty) {
+    MOZ_RELEASE_ASSERT(rb.BufferLength().isSome());
+    BlocksRingBuffer::State state = rb.GetState();
+    if (aExpectEmpty) {
+      MOZ_RELEASE_ASSERT(state.mRangeStart == state.mRangeEnd);
+      MOZ_RELEASE_ASSERT(state.mPushedBlockCount == 0);
+      MOZ_RELEASE_ASSERT(state.mClearedBlockCount == 0);
+    } else {
+      MOZ_RELEASE_ASSERT(state.mRangeStart < state.mRangeEnd);
+      MOZ_RELEASE_ASSERT(state.mPushedBlockCount > 0);
+      MOZ_RELEASE_ASSERT(state.mClearedBlockCount <= state.mPushedBlockCount);
+    }
+    int32_t ran = 0;
+    // The following three `Put...` will write three int32_t of value 1.
+    bi = rb.Put(sizeof(ran),
+                [&](BlocksRingBuffer::EntryWriter* aMaybeEntryWriter) {
+                  MOZ_RELEASE_ASSERT(!!aMaybeEntryWriter);
+                  ++ran;
+                  aMaybeEntryWriter->WriteObject(ran);
+                  return aMaybeEntryWriter->CurrentBlockIndex();
+                });
+    MOZ_RELEASE_ASSERT(ran == 1);
+    MOZ_RELEASE_ASSERT(rb.PutFrom(&ran, sizeof(ran)) !=
+                       BlocksRingBuffer::BlockIndex{});
+    MOZ_RELEASE_ASSERT(rb.PutObject(ran) != BlocksRingBuffer::BlockIndex{});
+    ran = 0;
+    rb.Read([&](BlocksRingBuffer::Reader* aReader) {
+      MOZ_RELEASE_ASSERT(!!aReader);
+      ++ran;
+    });
+    MOZ_RELEASE_ASSERT(ran == 1);
+    ran = 0;
+    rb.ReadEach([&](BlocksRingBuffer::EntryReader& aEntryReader) {
+      MOZ_RELEASE_ASSERT(aEntryReader.RemainingBytes() == sizeof(ran));
+      MOZ_RELEASE_ASSERT(aEntryReader.ReadObject<decltype(ran)>() == 1);
+      ++ran;
+    });
+    MOZ_RELEASE_ASSERT(ran >= 3);
+    ran = 0;
+    rb.ReadAt(BlocksRingBuffer::BlockIndex{},
+              [&](Maybe<BlocksRingBuffer::EntryReader>&& aMaybeEntryReader) {
+                MOZ_RELEASE_ASSERT(aMaybeEntryReader.isNothing());
+                ++ran;
+              });
+    MOZ_RELEASE_ASSERT(ran == 1);
+    ran = 0;
+    rb.ReadAt(bi,
+              [&](Maybe<BlocksRingBuffer::EntryReader>&& aMaybeEntryReader) {
+                MOZ_RELEASE_ASSERT(aMaybeEntryReader.isNothing() == !bi);
+                ++ran;
+              });
+    MOZ_RELEASE_ASSERT(ran == 1);
+  };
+
+  testInSession(EMPTY);
+  testInSession(NOT_EMPTY);
+
+  rb.Set(MakePowerOfTwo<BlocksRingBuffer::Length, 32>());
+  MOZ_RELEASE_ASSERT(rb.BufferLength().isSome());
+  rb.ReadEach([](auto&&) { MOZ_RELEASE_ASSERT(false); });
+
+  testInSession(EMPTY);
+  testInSession(NOT_EMPTY);
+
+  rb.Reset();
+  testOutOfSession();
+  testOutOfSession();
+
+  uint8_t buffer[MBSize * 3];
+  for (size_t i = 0; i < MBSize * 3; ++i) {
+    buffer[i] = uint8_t('A' + i);
+  }
+
+  rb.Set(&buffer[MBSize], MakePowerOfTwo<BlocksRingBuffer::Length, MBSize>());
+  MOZ_RELEASE_ASSERT(rb.BufferLength().isSome());
+  rb.ReadEach([](auto&&) { MOZ_RELEASE_ASSERT(false); });
+
+  testInSession(EMPTY);
+  testInSession(NOT_EMPTY);
+
+  rb.Reset();
+  testOutOfSession();
+  testOutOfSession();
+
+  rb.Set(&buffer[MBSize], MakePowerOfTwo<BlocksRingBuffer::Length, MBSize>());
+  MOZ_RELEASE_ASSERT(rb.BufferLength().isSome());
+  rb.ReadEach([](auto&&) { MOZ_RELEASE_ASSERT(false); });
+
+  testInSession(EMPTY);
+  testInSession(NOT_EMPTY);
+
+  // Remove the current underlying buffer, this should clear all entries.
+  rb.Reset();
+
+  // Check that only the provided stack-based sub-buffer was modified.
+  uint32_t changed = 0;
+  for (size_t i = MBSize; i < MBSize * 2; ++i) {
+    changed += (buffer[i] == uint8_t('A' + i)) ? 0 : 1;
+  }
+  // Expect at least 75% changes.
+  MOZ_RELEASE_ASSERT(changed >= MBSize * 6 / 8);
+
+  // Everything around the sub-buffer should be unchanged.
+  for (size_t i = 0; i < MBSize; ++i) {
+    MOZ_RELEASE_ASSERT(buffer[i] == uint8_t('A' + i));
+  }
+  for (size_t i = MBSize * 2; i < MBSize * 3; ++i) {
+    MOZ_RELEASE_ASSERT(buffer[i] == uint8_t('A' + i));
+  }
+
+  testOutOfSession();
+  testOutOfSession();
+
+  printf("TestBlocksRingBufferUnderlyingBufferChanges done\n");
+}
+
+void TestBlocksRingBufferThreading() {
+  printf("TestBlocksRingBufferThreading...\n");
+
+  constexpr uint32_t MBSize = 8192;
+  uint8_t buffer[MBSize * 3];
+  for (size_t i = 0; i < MBSize * 3; ++i) {
+    buffer[i] = uint8_t('A' + i);
+  }
+  BlocksRingBuffer rb(BlocksRingBuffer::ThreadSafety::WithMutex,
+                      &buffer[MBSize], MakePowerOfTwo32<MBSize>());
+
+  // Start reader thread.
+  std::atomic<bool> stopReader{false};
+  std::thread reader([&]() {
+    for (;;) {
+      BlocksRingBuffer::State state = rb.GetState();
+      printf(
+          "Reader: range=%llu..%llu (%llu bytes) pushed=%llu cleared=%llu "
+          "(alive=%llu)\n",
+          static_cast<unsigned long long>(ExtractBlockIndex(state.mRangeStart)),
+          static_cast<unsigned long long>(ExtractBlockIndex(state.mRangeEnd)),
+          static_cast<unsigned long long>(ExtractBlockIndex(state.mRangeEnd)) -
+              static_cast<unsigned long long>(
+                  ExtractBlockIndex(state.mRangeStart)),
+          static_cast<unsigned long long>(state.mPushedBlockCount),
+          static_cast<unsigned long long>(state.mClearedBlockCount),
+          static_cast<unsigned long long>(state.mPushedBlockCount -
+                                          state.mClearedBlockCount));
+      if (stopReader) {
+        break;
+      }
+      ::SleepMilli(1);
+    }
+  });
+
+  // Start writer threads.
+  constexpr int ThreadCount = 32;
+  std::thread threads[ThreadCount];
+  for (int threadNo = 0; threadNo < ThreadCount; ++threadNo) {
+    threads[threadNo] = std::thread(
+        [&](int aThreadNo) {
+          ::SleepMilli(1);
+          constexpr int pushCount = 1024;
+          for (int push = 0; push < pushCount; ++push) {
+            // Reserve as many bytes as the thread number (but at least enough
+            // to store an int), and write an increasing int.
+            rb.Put(std::max(aThreadNo, int(sizeof(push))),
+                   [&](BlocksRingBuffer::EntryWriter* aEW) {
+                     MOZ_RELEASE_ASSERT(!!aEW);
+                     aEW->WriteObject(aThreadNo * 1000000 + push);
+                     *aEW += aEW->RemainingBytes();
+                   });
+          }
+        },
+        threadNo);
+  }
+
+  // Wait for all writer threads to die.
+  for (auto&& thread : threads) {
+    thread.join();
+  }
+
+  // Stop reader thread.
+  stopReader = true;
+  reader.join();
+
+  // Check that only the provided stack-based sub-buffer was modified.
+  uint32_t changed = 0;
+  for (size_t i = MBSize; i < MBSize * 2; ++i) {
+    changed += (buffer[i] == uint8_t('A' + i)) ? 0 : 1;
+  }
+  // Expect at least 75% changes.
+  MOZ_RELEASE_ASSERT(changed >= MBSize * 6 / 8);
+
+  // Everything around the sub-buffer should be unchanged.
+  for (size_t i = 0; i < MBSize; ++i) {
+    MOZ_RELEASE_ASSERT(buffer[i] == uint8_t('A' + i));
+  }
+  for (size_t i = MBSize * 2; i < MBSize * 3; ++i) {
+    MOZ_RELEASE_ASSERT(buffer[i] == uint8_t('A' + i));
+  }
+
+  printf("TestBlocksRingBufferThreading done\n");
+}
+
+void TestBlocksRingBufferSerialization() {
+  printf("TestBlocksRingBufferSerialization...\n");
+
+  constexpr uint32_t MBSize = 64;
+  uint8_t buffer[MBSize * 3];
+  for (size_t i = 0; i < MBSize * 3; ++i) {
+    buffer[i] = uint8_t('A' + i);
+  }
+  BlocksRingBuffer rb(BlocksRingBuffer::ThreadSafety::WithMutex,
+                      &buffer[MBSize], MakePowerOfTwo32<MBSize>());
+
+  // Will expect literal string to always have the same address.
+#  define THE_ANSWER "The answer is "
+  const char* theAnswer = THE_ANSWER;
+
+  rb.PutObjects('0', WrapBlocksRingBufferLiteralCStringPointer(THE_ANSWER), 42,
+                std::string(" but pi="), 3.14);
+  rb.ReadEach([&](BlocksRingBuffer::EntryReader& aER) {
+    char c0;
+    const char* answer;
+    int integer;
+    std::string str;
+    double pi;
+    aER.ReadIntoObjects(c0, answer, integer, str, pi);
+    MOZ_RELEASE_ASSERT(c0 == '0');
+    MOZ_RELEASE_ASSERT(answer == theAnswer);
+    MOZ_RELEASE_ASSERT(integer == 42);
+    MOZ_RELEASE_ASSERT(str == " but pi=");
+    MOZ_RELEASE_ASSERT(pi == 3.14);
+  });
+  rb.ReadEach([&](BlocksRingBuffer::EntryReader& aER) {
+    char c0 = aER.ReadObject<char>();
+    MOZ_RELEASE_ASSERT(c0 == '0');
+    const char* answer = aER.ReadObject<const char*>();
+    MOZ_RELEASE_ASSERT(answer == theAnswer);
+    int integer = aER.ReadObject<int>();
+    MOZ_RELEASE_ASSERT(integer == 42);
+    std::string str = aER.ReadObject<std::string>();
+    MOZ_RELEASE_ASSERT(str == " but pi=");
+    double pi = aER.ReadObject<double>();
+    MOZ_RELEASE_ASSERT(pi == 3.14);
+  });
+
+  rb.Clear();
+  // Write an int and store its BlockIndex.
+  BlocksRingBuffer::BlockIndex blockIndex = rb.PutObject(123);
+  // It should be non-0.
+  MOZ_RELEASE_ASSERT(blockIndex != BlocksRingBuffer::BlockIndex{});
+  // Write that BlockIndex.
+  rb.PutObject(blockIndex);
+  rb.Read([&](BlocksRingBuffer::Reader* aR) {
+    BlocksRingBuffer::BlockIterator it = aR->begin();
+    const BlocksRingBuffer::BlockIterator itEnd = aR->end();
+    MOZ_RELEASE_ASSERT(it != itEnd);
+    MOZ_RELEASE_ASSERT((*it).ReadObject<int>() == 123);
+    ++it;
+    MOZ_RELEASE_ASSERT(it != itEnd);
+    MOZ_RELEASE_ASSERT((*it).ReadObject<BlocksRingBuffer::BlockIndex>() ==
+                       blockIndex);
+    ++it;
+    MOZ_RELEASE_ASSERT(it == itEnd);
+  });
+
+  rb.Clear();
+  rb.PutObjects(std::make_tuple(
+      '0', WrapBlocksRingBufferLiteralCStringPointer(THE_ANSWER), 42,
+      std::string(" but pi="), 3.14));
+  rb.ReadEach([&](BlocksRingBuffer::EntryReader& aER) {
+    MOZ_RELEASE_ASSERT(aER.ReadObject<char>() == '0');
+    MOZ_RELEASE_ASSERT(aER.ReadObject<const char*>() == theAnswer);
+    MOZ_RELEASE_ASSERT(aER.ReadObject<int>() == 42);
+    MOZ_RELEASE_ASSERT(aER.ReadObject<std::string>() == " but pi=");
+    MOZ_RELEASE_ASSERT(aER.ReadObject<double>() == 3.14);
+  });
+
+  rb.Clear();
+  rb.PutObjects(MakeTuple('0',
+                          WrapBlocksRingBufferLiteralCStringPointer(THE_ANSWER),
+                          42, std::string(" but pi="), 3.14));
+  rb.ReadEach([&](BlocksRingBuffer::EntryReader& aER) {
+    MOZ_RELEASE_ASSERT(aER.ReadObject<char>() == '0');
+    MOZ_RELEASE_ASSERT(aER.ReadObject<const char*>() == theAnswer);
+    MOZ_RELEASE_ASSERT(aER.ReadObject<int>() == 42);
+    MOZ_RELEASE_ASSERT(aER.ReadObject<std::string>() == " but pi=");
+    MOZ_RELEASE_ASSERT(aER.ReadObject<double>() == 3.14);
+  });
+
+  rb.Clear();
+  {
+    UniqueFreePtr<char> ufps(strdup(THE_ANSWER));
+    rb.PutObjects(ufps);
+  }
+  rb.ReadEach([&](BlocksRingBuffer::EntryReader& aER) {
+    auto ufps = aER.ReadObject<UniqueFreePtr<char>>();
+    MOZ_RELEASE_ASSERT(!!ufps);
+    MOZ_RELEASE_ASSERT(std::string(THE_ANSWER) == ufps.get());
+  });
+
+  rb.Clear();
+  int intArray[] = {1, 2, 3, 4, 5};
+  rb.PutObjects(MakeSpan(intArray));
+  rb.ReadEach([&](BlocksRingBuffer::EntryReader& aER) {
+    int intArrayOut[sizeof(intArray) / sizeof(intArray[0])] = {0};
+    auto outSpan = MakeSpan(intArrayOut);
+    aER.ReadIntoObject(outSpan);
+    for (size_t i = 0; i < sizeof(intArray) / sizeof(intArray[0]); ++i) {
+      MOZ_RELEASE_ASSERT(intArrayOut[i] == intArray[i]);
+    }
+  });
+
+  rb.Clear();
+  rb.PutObjects(Maybe<int>(Nothing{}), Maybe<int>(Some(123)));
+  rb.ReadEach([&](BlocksRingBuffer::EntryReader& aER) {
+    Maybe<int> mi0, mi1;
+    aER.ReadIntoObjects(mi0, mi1);
+    MOZ_RELEASE_ASSERT(mi0.isNothing());
+    MOZ_RELEASE_ASSERT(mi1.isSome());
+    MOZ_RELEASE_ASSERT(*mi1 == 123);
+  });
+
+  rb.Clear();
+  using V = Variant<int, double, int>;
+  V v0(VariantIndex<0>{}, 123);
+  V v1(3.14);
+  V v2(VariantIndex<2>{}, 456);
+  rb.PutObjects(v0, v1, v2);
+  rb.ReadEach([&](BlocksRingBuffer::EntryReader& aER) {
+    MOZ_RELEASE_ASSERT(aER.ReadObject<V>() == v0);
+    MOZ_RELEASE_ASSERT(aER.ReadObject<V>() == v1);
+    MOZ_RELEASE_ASSERT(aER.ReadObject<V>() == v2);
+  });
+
+  // 2nd BlocksRingBuffer to contain the 1st one. It has be be more than twice
+  // the size.
+  constexpr uint32_t MBSize2 = MBSize * 4;
+  uint8_t buffer2[MBSize2 * 3];
+  for (size_t i = 0; i < MBSize2 * 3; ++i) {
+    buffer2[i] = uint8_t('B' + i);
+  }
+  BlocksRingBuffer rb2(BlocksRingBuffer::ThreadSafety::WithoutMutex,
+                       &buffer2[MBSize2], MakePowerOfTwo32<MBSize2>());
+  rb2.PutObject(rb);
+
+  // 3rd BlocksRingBuffer deserialized from the 2nd one.
+  uint8_t buffer3[MBSize * 3];
+  for (size_t i = 0; i < MBSize * 3; ++i) {
+    buffer3[i] = uint8_t('C' + i);
+  }
+  BlocksRingBuffer rb3(BlocksRingBuffer::ThreadSafety::WithoutMutex,
+                       &buffer3[MBSize], MakePowerOfTwo32<MBSize>());
+  rb2.ReadEach(
+      [&](BlocksRingBuffer::EntryReader& aER) { aER.ReadIntoObject(rb3); });
+
+  // And a 4th heap-allocated one.
+  UniquePtr<BlocksRingBuffer> rb4up;
+  rb2.ReadEach([&](BlocksRingBuffer::EntryReader& aER) {
+    rb4up = aER.ReadObject<UniquePtr<BlocksRingBuffer>>();
+  });
+  MOZ_RELEASE_ASSERT(!!rb4up);
+
+  // Clear 1st and 2nd BlocksRingBuffers, to ensure we have made a deep copy
+  // into the 3rd&4th ones.
+  rb.Clear();
+  rb2.Clear();
+
+  // And now the 3rd one should have the same contents as the 1st one had.
+  rb3.ReadEach([&](BlocksRingBuffer::EntryReader& aER) {
+    MOZ_RELEASE_ASSERT(aER.ReadObject<V>() == v0);
+    MOZ_RELEASE_ASSERT(aER.ReadObject<V>() == v1);
+    MOZ_RELEASE_ASSERT(aER.ReadObject<V>() == v2);
+  });
+
+  // And 4th.
+  rb4up->ReadEach([&](BlocksRingBuffer::EntryReader& aER) {
+    MOZ_RELEASE_ASSERT(aER.ReadObject<V>() == v0);
+    MOZ_RELEASE_ASSERT(aER.ReadObject<V>() == v1);
+    MOZ_RELEASE_ASSERT(aER.ReadObject<V>() == v2);
+  });
+
+  // In fact, the 3rd and 4th ones should have the same state, because they were
+  // created the same way.
+  MOZ_RELEASE_ASSERT(rb3.GetState().mRangeStart ==
+                     rb4up->GetState().mRangeStart);
+  MOZ_RELEASE_ASSERT(rb3.GetState().mRangeEnd == rb4up->GetState().mRangeEnd);
+  MOZ_RELEASE_ASSERT(rb3.GetState().mPushedBlockCount ==
+                     rb4up->GetState().mPushedBlockCount);
+  MOZ_RELEASE_ASSERT(rb3.GetState().mClearedBlockCount ==
+                     rb4up->GetState().mClearedBlockCount);
+
+  // Check that only the provided stack-based sub-buffer was modified.
+  uint32_t changed = 0;
+  for (size_t i = MBSize; i < MBSize * 2; ++i) {
+    changed += (buffer[i] == uint8_t('A' + i)) ? 0 : 1;
+  }
+  // Expect at least 75% changes.
+  MOZ_RELEASE_ASSERT(changed >= MBSize * 6 / 8);
+
+  // Everything around the sub-buffers should be unchanged.
+  for (size_t i = 0; i < MBSize; ++i) {
+    MOZ_RELEASE_ASSERT(buffer[i] == uint8_t('A' + i));
+  }
+  for (size_t i = MBSize * 2; i < MBSize * 3; ++i) {
+    MOZ_RELEASE_ASSERT(buffer[i] == uint8_t('A' + i));
+  }
+
+  for (size_t i = 0; i < MBSize2; ++i) {
+    MOZ_RELEASE_ASSERT(buffer2[i] == uint8_t('B' + i));
+  }
+  for (size_t i = MBSize2 * 2; i < MBSize2 * 3; ++i) {
+    MOZ_RELEASE_ASSERT(buffer2[i] == uint8_t('B' + i));
+  }
+
+  for (size_t i = 0; i < MBSize; ++i) {
+    MOZ_RELEASE_ASSERT(buffer3[i] == uint8_t('C' + i));
+  }
+  for (size_t i = MBSize * 2; i < MBSize * 3; ++i) {
+    MOZ_RELEASE_ASSERT(buffer3[i] == uint8_t('C' + i));
+  }
+
+  printf("TestBlocksRingBufferSerialization done\n");
+}
+
+class BaseTestMarkerPayload : public baseprofiler::ProfilerMarkerPayload {
+ public:
+  explicit BaseTestMarkerPayload(int aData) : mData(aData) {}
+
+  int GetData() const { return mData; }
+
+  // Exploded DECL_BASE_STREAM_PAYLOAD, but without `MFBT_API`s.
+  static UniquePtr<ProfilerMarkerPayload> Deserialize(
+      BlocksRingBuffer::EntryReader& aEntryReader);
+  BlocksRingBuffer::Length TagAndSerializationBytes() const override;
+  void SerializeTagAndPayload(
+      BlocksRingBuffer::EntryWriter& aEntryWriter) const override;
+  void StreamPayload(
+      ::mozilla::baseprofiler::SpliceableJSONWriter& aWriter,
+      const ::mozilla::TimeStamp& aProcessStartTime,
+      ::mozilla::baseprofiler::UniqueStacks& aUniqueStacks) const override;
+
+ private:
+  BaseTestMarkerPayload(CommonProps&& aProps, int aData)
+      : baseprofiler::ProfilerMarkerPayload(std::move(aProps)), mData(aData) {}
+
+  int mData;
+};
+
+// static
+UniquePtr<baseprofiler::ProfilerMarkerPayload>
+BaseTestMarkerPayload::Deserialize(
+    BlocksRingBuffer::EntryReader& aEntryReader) {
+  CommonProps props = DeserializeCommonProps(aEntryReader);
+  int data = aEntryReader.ReadObject<int>();
+  return UniquePtr<baseprofiler::ProfilerMarkerPayload>(
+      new BaseTestMarkerPayload(std::move(props), data));
+}
+
+BlocksRingBuffer::Length BaseTestMarkerPayload::TagAndSerializationBytes()
+    const {
+  return CommonPropsTagAndSerializationBytes() + sizeof(int);
+}
+
+void BaseTestMarkerPayload::SerializeTagAndPayload(
+    BlocksRingBuffer::EntryWriter& aEntryWriter) const {
+  static const DeserializerTag tag = TagForDeserializer(Deserialize);
+  SerializeTagAndCommonProps(tag, aEntryWriter);
+  aEntryWriter.WriteObject(mData);
+}
+
+void BaseTestMarkerPayload::StreamPayload(
+    baseprofiler::SpliceableJSONWriter& aWriter,
+    const TimeStamp& aProcessStartTime,
+    baseprofiler::UniqueStacks& aUniqueStacks) const {
+  aWriter.IntProperty("data", mData);
+}
+
+void TestProfilerMarkerSerialization() {
+  printf("TestProfilerMarkerSerialization...\n");
+
+  constexpr uint32_t MBSize = 256;
+  uint8_t buffer[MBSize * 3];
+  for (size_t i = 0; i < MBSize * 3; ++i) {
+    buffer[i] = uint8_t('A' + i);
+  }
+  BlocksRingBuffer rb(BlocksRingBuffer::ThreadSafety::WithMutex,
+                      &buffer[MBSize], MakePowerOfTwo32<MBSize>());
+
+  constexpr int data = 42;
+  {
+    BaseTestMarkerPayload payload(data);
+    rb.PutObject(
+        static_cast<const baseprofiler::ProfilerMarkerPayload*>(&payload));
+  }
+
+  int read = 0;
+  rb.ReadEach([&](BlocksRingBuffer::EntryReader& aER) {
+    UniquePtr<baseprofiler::ProfilerMarkerPayload> payload =
+        aER.ReadObject<UniquePtr<baseprofiler::ProfilerMarkerPayload>>();
+    MOZ_RELEASE_ASSERT(!!payload);
+    ++read;
+    BaseTestMarkerPayload* testPayload =
+        static_cast<BaseTestMarkerPayload*>(payload.get());
+    MOZ_RELEASE_ASSERT(testPayload);
+    MOZ_RELEASE_ASSERT(testPayload->GetData() == data);
+  });
+  MOZ_RELEASE_ASSERT(read == 1);
+
+  // Everything around the sub-buffer should be unchanged.
+  for (size_t i = 0; i < MBSize; ++i) {
+    MOZ_RELEASE_ASSERT(buffer[i] == uint8_t('A' + i));
+  }
+  for (size_t i = MBSize * 2; i < MBSize * 3; ++i) {
+    MOZ_RELEASE_ASSERT(buffer[i] == uint8_t('A' + i));
+  }
+
+  printf("TestProfilerMarkerSerialization done\n");
+}
+
+// Increase the depth, to a maximum (to avoid too-deep recursion).
+static constexpr size_t NextDepth(size_t aDepth) {
+  constexpr size_t MAX_DEPTH = 128;
+  return (aDepth < MAX_DEPTH) ? (aDepth + 1) : aDepth;
+}
+
+Atomic<bool, Relaxed, recordreplay::Behavior::DontPreserve> sStopFibonacci;
+
+// Compute fibonacci the hard way (recursively: `f(n)=f(n-1)+f(n-2)`), and
+// prevent inlining.
+// The template parameter makes each depth be a separate function, to better
+// distinguish them in the profiler output.
+template <size_t DEPTH = 0>
+MOZ_NEVER_INLINE unsigned long long Fibonacci(unsigned long long n) {
+  AUTO_BASE_PROFILER_LABEL_DYNAMIC_STRING("fib", OTHER, std::to_string(DEPTH));
+  if (n == 0) {
+    return 0;
+  }
+  if (n == 1) {
+    return 1;
+  }
+  if (DEPTH < 5 && sStopFibonacci) {
+    return 1'000'000'000;
+  }
+  TimeStamp start = TimeStamp::NowUnfuzzed();
+  static constexpr size_t MAX_MARKER_DEPTH = 10;
+  unsigned long long f2 = Fibonacci<NextDepth(DEPTH)>(n - 2);
+  if (DEPTH == 0) {
+    BASE_PROFILER_ADD_MARKER("Half-way through Fibonacci", OTHER);
+  }
+  unsigned long long f1 = Fibonacci<NextDepth(DEPTH)>(n - 1);
+  if (DEPTH < MAX_MARKER_DEPTH) {
+    baseprofiler::profiler_add_text_marker(
+        "fib", std::to_string(DEPTH),
+        baseprofiler::ProfilingCategoryPair::OTHER, start,
+        TimeStamp::NowUnfuzzed());
+  }
+  return f2 + f1;
+}
+
 void TestProfiler() {
   printf("TestProfiler starting -- pid: %d, tid: %d\n",
          baseprofiler::profiler_current_process_id(),
          baseprofiler::profiler_current_thread_id());
-  // ::Sleep(10000);
+  // ::SleepMilli(10000);
+
+  // Test dependencies.
+  TestPowerOfTwoMask();
+  TestPowerOfTwo();
+  TestLEB128();
+  TestModuloBuffer();
+  TestBlocksRingBufferAPI();
+  TestBlocksRingBufferUnderlyingBufferChanges();
+  TestBlocksRingBufferThreading();
+  TestBlocksRingBufferSerialization();
+  TestProfilerMarkerSerialization();
 
   {
     printf("profiler_init()...\n");
@@ -82,7 +1619,7 @@ void TestProfiler() {
     MOZ_RELEASE_ASSERT(!baseprofiler::profiler_thread_is_sleeping());
 
     printf("profiler_start()...\n");
-    mozilla::Vector<const char*> filters;
+    Vector<const char*> filters;
     // Profile all registered threads.
     MOZ_RELEASE_ASSERT(filters.append(""));
     const uint32_t features = baseprofiler::ProfilerFeature::Leaf |
@@ -96,22 +1633,148 @@ void TestProfiler() {
     MOZ_RELEASE_ASSERT(baseprofiler::profiler_thread_is_being_profiled());
     MOZ_RELEASE_ASSERT(!baseprofiler::profiler_thread_is_sleeping());
 
-    {
+    sStopFibonacci = false;
+
+    std::thread threadFib([]() {
+      AUTO_BASE_PROFILER_REGISTER_THREAD("fibonacci");
+      SleepMilli(5);
+      auto cause =
+#  if defined(__linux__) || defined(__ANDROID__)
+          // Currently disabled on these platforms, so just return a null.
+          decltype(baseprofiler::profiler_get_backtrace()){};
+#  else
+          baseprofiler::profiler_get_backtrace();
+#  endif
       AUTO_BASE_PROFILER_TEXT_MARKER_CAUSE("fibonacci", "First leaf call",
-                                           OTHER, nullptr);
-      static const unsigned long long fibStart = 40;
+                                           OTHER, std::move(cause));
+      static const unsigned long long fibStart = 37;
       printf("Fibonacci(%llu)...\n", fibStart);
       AUTO_BASE_PROFILER_LABEL("Label around Fibonacci", OTHER);
       unsigned long long f = Fibonacci(fibStart);
       printf("Fibonacci(%llu) = %llu\n", fibStart, f);
+    });
+
+    std::thread threadCancelFib([]() {
+      AUTO_BASE_PROFILER_REGISTER_THREAD("fibonacci canceller");
+      SleepMilli(5);
+      AUTO_BASE_PROFILER_TEXT_MARKER_CAUSE("fibonacci", "Canceller", OTHER,
+                                           nullptr);
+      static const int waitMaxSeconds = 10;
+      for (int i = 0; i < waitMaxSeconds; ++i) {
+        if (sStopFibonacci) {
+          AUTO_BASE_PROFILER_LABEL_DYNAMIC_STRING("fibCancel", OTHER,
+                                                  std::to_string(i));
+          return;
+        }
+        AUTO_BASE_PROFILER_THREAD_SLEEP;
+        SleepMilli(1000);
+      }
+      AUTO_BASE_PROFILER_LABEL_DYNAMIC_STRING("fibCancel", OTHER,
+                                              "Cancelling!");
+      sStopFibonacci = true;
+    });
+
+    {
+      AUTO_BASE_PROFILER_TEXT_MARKER_CAUSE(
+          "main thread", "joining fibonacci thread", OTHER, nullptr);
+      AUTO_BASE_PROFILER_THREAD_SLEEP;
+      threadFib.join();
     }
 
+    {
+      AUTO_BASE_PROFILER_TEXT_MARKER_CAUSE(
+          "main thread", "joining fibonacci-canceller thread", OTHER, nullptr);
+      sStopFibonacci = true;
+      AUTO_BASE_PROFILER_THREAD_SLEEP;
+      threadCancelFib.join();
+    }
+
+    // Just making sure all payloads know how to (de)serialize and stream.
+    baseprofiler::profiler_add_marker(
+        "TracingMarkerPayload", baseprofiler::ProfilingCategoryPair::OTHER,
+        baseprofiler::TracingMarkerPayload("category",
+                                           baseprofiler::TRACING_EVENT));
+
+    auto cause =
+#  if defined(__linux__) || defined(__ANDROID__)
+        // Currently disabled on these platforms, so just return a null.
+        decltype(baseprofiler::profiler_get_backtrace()){};
+#  else
+        baseprofiler::profiler_get_backtrace();
+#  endif
+    baseprofiler::profiler_add_marker(
+        "FileIOMarkerPayload", baseprofiler::ProfilingCategoryPair::OTHER,
+        baseprofiler::FileIOMarkerPayload(
+            "operation", "source", "filename", TimeStamp::NowUnfuzzed(),
+            TimeStamp::NowUnfuzzed(), std::move(cause)));
+
+    baseprofiler::profiler_add_marker(
+        "UserTimingMarkerPayload", baseprofiler::ProfilingCategoryPair::OTHER,
+        baseprofiler::UserTimingMarkerPayload("name", TimeStamp::NowUnfuzzed(),
+                                              Nothing{}, Nothing{}));
+
+    baseprofiler::profiler_add_marker(
+        "HangMarkerPayload", baseprofiler::ProfilingCategoryPair::OTHER,
+        baseprofiler::HangMarkerPayload(TimeStamp::NowUnfuzzed(),
+                                        TimeStamp::NowUnfuzzed()));
+
+    baseprofiler::profiler_add_marker(
+        "LongTaskMarkerPayload", baseprofiler::ProfilingCategoryPair::OTHER,
+        baseprofiler::LongTaskMarkerPayload(TimeStamp::NowUnfuzzed(),
+                                            TimeStamp::NowUnfuzzed()));
+
+    {
+      std::string s = "text payload";
+      baseprofiler::profiler_add_marker(
+          "TextMarkerPayload", baseprofiler::ProfilingCategoryPair::OTHER,
+          baseprofiler::TextMarkerPayload(s, TimeStamp::NowUnfuzzed(),
+                                          TimeStamp::NowUnfuzzed()));
+    }
+
+    baseprofiler::profiler_add_marker(
+        "LogMarkerPayload", baseprofiler::ProfilingCategoryPair::OTHER,
+        baseprofiler::LogMarkerPayload("module", "text",
+                                       TimeStamp::NowUnfuzzed()));
+
     printf("Sleep 1s...\n");
     {
       AUTO_BASE_PROFILER_THREAD_SLEEP;
       SleepMilli(1000);
     }
 
+    Maybe<baseprofiler::ProfilerBufferInfo> info =
+        baseprofiler::profiler_get_buffer_info();
+    MOZ_RELEASE_ASSERT(info.isSome());
+    printf("Profiler buffer range: %llu .. %llu (%llu bytes)\n",
+           static_cast<unsigned long long>(info->mRangeStart),
+           static_cast<unsigned long long>(info->mRangeEnd),
+           // sizeof(ProfileBufferEntry) == 9
+           (static_cast<unsigned long long>(info->mRangeEnd) -
+            static_cast<unsigned long long>(info->mRangeStart)) *
+               9);
+    printf("Stats:         min(ns) .. mean(ns) .. max(ns)  [count]\n");
+    printf("- Intervals:   %7.1f .. %7.1f  .. %7.1f  [%u]\n",
+           info->mIntervalsNs.min,
+           info->mIntervalsNs.sum / info->mIntervalsNs.n,
+           info->mIntervalsNs.max, info->mIntervalsNs.n);
+    printf("- Overheads:   %7.1f .. %7.1f  .. %7.1f  [%u]\n",
+           info->mOverheadsNs.min,
+           info->mOverheadsNs.sum / info->mOverheadsNs.n,
+           info->mOverheadsNs.max, info->mOverheadsNs.n);
+    printf("  - Locking:   %7.1f .. %7.1f  .. %7.1f  [%u]\n",
+           info->mLockingsNs.min, info->mLockingsNs.sum / info->mLockingsNs.n,
+           info->mLockingsNs.max, info->mLockingsNs.n);
+    printf("  - Clearning: %7.1f .. %7.1f  .. %7.1f  [%u]\n",
+           info->mCleaningsNs.min,
+           info->mCleaningsNs.sum / info->mCleaningsNs.n,
+           info->mCleaningsNs.max, info->mCleaningsNs.n);
+    printf("  - Counters:  %7.1f .. %7.1f  .. %7.1f  [%u]\n",
+           info->mCountersNs.min, info->mCountersNs.sum / info->mCountersNs.n,
+           info->mCountersNs.max, info->mCountersNs.n);
+    printf("  - Threads:   %7.1f .. %7.1f  .. %7.1f  [%u]\n",
+           info->mThreadsNs.min, info->mThreadsNs.sum / info->mThreadsNs.n,
+           info->mThreadsNs.max, info->mThreadsNs.n);
+
     printf("baseprofiler_save_profile_to_file()...\n");
     baseprofiler::profiler_save_profile_to_file("TestProfiler_profile.json");
 
diff --git a/netwerk/base/Predictor.cpp b/netwerk/base/Predictor.cpp
index ee3280a3d3..dc9626cda6 100644
--- a/netwerk/base/Predictor.cpp
+++ b/netwerk/base/Predictor.cpp
@@ -943,9 +943,8 @@ void Predictor::CalculatePredictions(nsICacheEntry* entry, nsIURI* referrer,
   // Since the visitor gets called under a cache lock, all we do there is get
   // copies of the keys/values we care about, and then do the real work here
   entry->VisitMetaData(this);
-  nsTArray<nsCString> keysToOperateOn, valuesToOperateOn;
-  keysToOperateOn.SwapElements(mKeysToOperateOn);
-  valuesToOperateOn.SwapElements(mValuesToOperateOn);
+  nsTArray<nsCString> keysToOperateOn = std::move(mKeysToOperateOn),
+                      valuesToOperateOn = std::move(mValuesToOperateOn);
 
   MOZ_ASSERT(keysToOperateOn.Length() == valuesToOperateOn.Length());
   for (size_t i = 0; i < keysToOperateOn.Length(); ++i) {
@@ -1148,10 +1147,9 @@ bool Predictor::RunPredictions(nsIURI* referrer,
   bool predicted = false;
   uint32_t len, i;
 
-  nsTArray<nsCOMPtr<nsIURI>> prefetches, preconnects, preresolves;
-  prefetches.SwapElements(mPrefetches);
-  preconnects.SwapElements(mPreconnects);
-  preresolves.SwapElements(mPreresolves);
+  nsTArray<nsCOMPtr<nsIURI>> prefetches = std::move(mPrefetches),
+                             preconnects = std::move(mPreconnects),
+                             preresolves = std::move(mPreresolves);
 
   Telemetry::AutoCounter<Telemetry::PREDICTOR_TOTAL_PREDICTIONS>
       totalPredictions;
@@ -1461,9 +1459,8 @@ void Predictor::LearnInternal(PredictorLearnReason reason, nsICacheEntry* entry,
         // get copies of the keys/values we care about, and then do the real
         // work here
         entry->VisitMetaData(this);
-        nsTArray<nsCString> keysToOperateOn, valuesToOperateOn;
-        keysToOperateOn.SwapElements(mKeysToOperateOn);
-        valuesToOperateOn.SwapElements(mValuesToOperateOn);
+        nsTArray<nsCString> keysToOperateOn = std::move(mKeysToOperateOn),
+                            valuesToOperateOn = std::move(mValuesToOperateOn);
 
         MOZ_ASSERT(keysToOperateOn.Length() == valuesToOperateOn.Length());
         for (size_t i = 0; i < keysToOperateOn.Length(); ++i) {
@@ -1800,8 +1797,7 @@ Predictor::Resetter::OnCacheEntryAvailable(nsICacheEntry* entry, bool isNew,
   }
 
   entry->VisitMetaData(this);
-  nsTArray<nsCString> keysToDelete;
-  keysToDelete.SwapElements(mKeysToDelete);
+  nsTArray<nsCString> keysToDelete = std::move(mKeysToDelete);
 
   for (size_t i = 0; i < keysToDelete.Length(); ++i) {
     const char* key = keysToDelete[i].BeginReading();
@@ -1884,13 +1880,12 @@ Predictor::Resetter::OnCacheEntryVisitCompleted() {
 
   nsresult rv;
 
-  nsTArray<nsCOMPtr<nsIURI>> urisToVisit;
-  urisToVisit.SwapElements(mURIsToVisit);
+  nsTArray<nsCOMPtr<nsIURI>> urisToVisit = std::move(mURIsToVisit);
 
   MOZ_ASSERT(mEntriesToVisit == urisToVisit.Length());
 
-  nsTArray<nsCOMPtr<nsILoadContextInfo>> infosToVisit;
-  infosToVisit.SwapElements(mInfosToVisit);
+  nsTArray<nsCOMPtr<nsILoadContextInfo>> infosToVisit =
+      std::move(mInfosToVisit);
 
   MOZ_ASSERT(mEntriesToVisit == infosToVisit.Length());
 
@@ -2371,9 +2366,8 @@ Predictor::CacheabilityAction::OnCacheEntryAvailable(
     return NS_OK;
   }
 
-  nsTArray<nsCString> keysToCheck, valuesToCheck;
-  keysToCheck.SwapElements(mKeysToCheck);
-  valuesToCheck.SwapElements(mValuesToCheck);
+  nsTArray<nsCString> keysToCheck = std::move(mKeysToCheck),
+                      valuesToCheck = std::move(mValuesToCheck);
 
   bool hasQueryString = false;
   nsAutoCString query;
diff --git a/netwerk/base/ProxyAutoConfig.cpp b/netwerk/base/ProxyAutoConfig.cpp
index 89f1a0b699..c4cfa73781 100644
--- a/netwerk/base/ProxyAutoConfig.cpp
+++ b/netwerk/base/ProxyAutoConfig.cpp
@@ -397,14 +397,13 @@ class MOZ_STACK_CLASS AutoPACErrorReporter {
     if (!JS_IsExceptionPending(mCx)) {
       return;
     }
-    JS::RootedValue exn(mCx);
-    if (!JS_GetPendingException(mCx, &exn)) {
+    JS::ExceptionStack exnStack(mCx);
+    if (!JS::StealPendingExceptionStack(mCx, &exnStack)) {
       return;
     }
-    JS_ClearPendingException(mCx);
 
-    js::ErrorReport report(mCx);
-    if (!report.init(mCx, exn, js::ErrorReport::WithSideEffects)) {
+    JS::ErrorReportBuilder report(mCx);
+    if (!report.init(mCx, exnStack, JS::ErrorReportBuilder::WithSideEffects)) {
       JS_ClearPendingException(mCx);
       return;
     }
@@ -578,7 +577,7 @@ class JSContextWrapper {
     JSContext* cx = JS_NewContext(JS::DefaultHeapMaxBytes + aExtraHeapSize);
     if (NS_WARN_IF(!cx)) return nullptr;
 
-    JS::ContextOptionsRef(cx).setDisableIon();
+    JS::ContextOptionsRef(cx).setDisableIon().setDisableEvalSecurityChecks();
 
     JSContextWrapper* entry = new JSContextWrapper(cx);
     if (NS_FAILED(entry->Init())) {
diff --git a/netwerk/base/RequestContextService.cpp b/netwerk/base/RequestContextService.cpp
index 8fe41beee2..36305d0119 100644
--- a/netwerk/base/RequestContextService.cpp
+++ b/netwerk/base/RequestContextService.cpp
@@ -409,8 +409,7 @@ void RequestContext::ProcessTailQueue(nsresult aResult) {
   // Must drop to stop tailing requests
   mUntailAt = TimeStamp();
 
-  nsTArray<PendingTailRequest> queue;
-  queue.SwapElements(mTailQueue);
+  nsTArray<PendingTailRequest> queue = std::move(mTailQueue);
 
   for (const auto& request : queue) {
     LOG(("  untailing %p", request.get()));
diff --git a/netwerk/base/ThrottleQueue.cpp b/netwerk/base/ThrottleQueue.cpp
index 532f3f03c2..32ac14719b 100644
--- a/netwerk/base/ThrottleQueue.cpp
+++ b/netwerk/base/ThrottleQueue.cpp
@@ -312,8 +312,7 @@ ThrottleQueue::Notify(nsITimer* aTimer) {
   MOZ_ASSERT(OnSocketThread(), "not on socket thread");
   // A notified reader may need to push itself back on the queue.
   // Swap out the list of readers so that this works properly.
-  nsTArray<RefPtr<ThrottleInputStream>> events;
-  events.SwapElements(mAsyncEvents);
+  nsTArray<RefPtr<ThrottleInputStream>> events = std::move(mAsyncEvents);
 
   // Optimistically notify all the waiting readers, and then let them
   // requeue if there isn't enough bandwidth.
diff --git a/netwerk/base/nsIOService.cpp b/netwerk/base/nsIOService.cpp
index 26741202e6..e032ffb045 100644
--- a/netwerk/base/nsIOService.cpp
+++ b/netwerk/base/nsIOService.cpp
@@ -466,8 +466,7 @@ void nsIOService::OnProcessLaunchComplete(SocketProcessHost* aHost,
   }
 
   if (!mPendingEvents.IsEmpty()) {
-    nsTArray<std::function<void()>> pendingEvents;
-    mPendingEvents.SwapElements(pendingEvents);
+    nsTArray<std::function<void()>> pendingEvents = std::move(mPendingEvents);
     for (auto& func : pendingEvents) {
       func();
     }
diff --git a/netwerk/base/nsIOService.h b/netwerk/base/nsIOService.h
index 663aaba86c..6bb0b1f605 100644
--- a/netwerk/base/nsIOService.h
+++ b/netwerk/base/nsIOService.h
@@ -130,6 +130,8 @@ class nsIOService final : public nsIIOService,
   void CallOrWaitForSocketProcess(const std::function<void()>& aFunc);
 
   int32_t SocketProcessPid();
+  SocketProcessHost* SocketProcess() { return mSocketProcess; }
+
   friend SocketProcessMemoryReporter;
   RefPtr<MemoryReportingProcess> GetSocketProcessMemoryReporter();
 
diff --git a/netwerk/base/nsSocketTransportService2.cpp b/netwerk/base/nsSocketTransportService2.cpp
index 73530ddb4c..a06a7c3b61 100644
--- a/netwerk/base/nsSocketTransportService2.cpp
+++ b/netwerk/base/nsSocketTransportService2.cpp
@@ -959,6 +959,11 @@ nsSocketTransportService::Run() {
       startOfNextIteration = TimeStamp::NowLoRes();
     }
     pollDuration = nullptr;
+    // We pop out to this loop when there are no pending events.
+    // If we don't reset these, we may not re-enter ProcessNextEvent()
+    // until we have events to process, and it may seem like we have
+    // an event running for a very long time.
+    mRawThread->SetRunningEventDelay(TimeDuration(), TimeStamp());
 
     do {
       if (Telemetry::CanRecordPrereleaseData()) {
diff --git a/netwerk/base/nsUDPSocket.cpp b/netwerk/base/nsUDPSocket.cpp
index aa11a38d4e..dcb30849ae 100644
--- a/netwerk/base/nsUDPSocket.cpp
+++ b/netwerk/base/nsUDPSocket.cpp
@@ -173,10 +173,9 @@ NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(nsUDPMessage)
 NS_IMPL_CYCLE_COLLECTION_UNLINK_END
 
 nsUDPMessage::nsUDPMessage(NetAddr* aAddr, nsIOutputStream* aOutputStream,
-                           FallibleTArray<uint8_t>& aData)
-    : mOutputStream(aOutputStream) {
+                           FallibleTArray<uint8_t>&& aData)
+    : mOutputStream(aOutputStream), mData(std::move(aData)) {
   memcpy(&mAddr, aAddr, sizeof(NetAddr));
-  aData.SwapElements(mData);
 }
 
 nsUDPMessage::~nsUDPMessage() { DropJSObjects(this); }
@@ -328,10 +327,9 @@ namespace {
 class UDPMessageProxy final : public nsIUDPMessage {
  public:
   UDPMessageProxy(NetAddr* aAddr, nsIOutputStream* aOutputStream,
-                  FallibleTArray<uint8_t>& aData)
-      : mOutputStream(aOutputStream) {
+                  FallibleTArray<uint8_t>&& aData)
+      : mOutputStream(aOutputStream), mData(std::move(aData)) {
     memcpy(&mAddr, aAddr, sizeof(mAddr));
-    aData.SwapElements(mData);
   }
 
   NS_DECL_THREADSAFE_ISUPPORTS
@@ -442,7 +440,7 @@ void nsUDPSocket::OnSocketReady(PRFileDesc* fd, int16_t outFlags) {
   NetAddr netAddr;
   PRNetAddrToNetAddr(&prClientAddr, &netAddr);
   nsCOMPtr<nsIUDPMessage> message =
-      new UDPMessageProxy(&netAddr, pipeOut, data);
+      new UDPMessageProxy(&netAddr, pipeOut, std::move(data));
   mListener->OnPacketReceived(this, message);
 }
 
@@ -843,7 +841,7 @@ SocketListenerProxy::OnPacketReceivedRunnable::Run() {
   FallibleTArray<uint8_t>& data = mMessage->GetDataAsTArray();
 
   nsCOMPtr<nsIUDPMessage> message =
-      new nsUDPMessage(&netAddr, outputStream, data);
+      new nsUDPMessage(&netAddr, outputStream, std::move(data));
   mListener->OnPacketReceived(mSocket, message);
   return NS_OK;
 }
@@ -937,7 +935,7 @@ SocketListenerProxyBackground::OnPacketReceivedRunnable::Run() {
 
   UDPSOCKET_LOG(("%s [this=%p], len %zu", __FUNCTION__, this, data.Length()));
   nsCOMPtr<nsIUDPMessage> message =
-      new UDPMessageProxy(&netAddr, outputStream, data);
+      new UDPMessageProxy(&netAddr, outputStream, std::move(data));
   mListener->OnPacketReceived(mSocket, message);
   return NS_OK;
 }
@@ -954,10 +952,8 @@ class PendingSend : public nsIDNSListener {
   NS_DECL_NSIDNSLISTENER
 
   PendingSend(nsUDPSocket* aSocket, uint16_t aPort,
-              FallibleTArray<uint8_t>& aData)
-      : mSocket(aSocket), mPort(aPort) {
-    mData.SwapElements(aData);
-  }
+              FallibleTArray<uint8_t>&& aData)
+      : mSocket(aSocket), mPort(aPort), mData(std::move(aData)) {}
 
  private:
   virtual ~PendingSend() = default;
@@ -1095,7 +1091,7 @@ nsUDPSocket::Send(const nsACString& aHost, uint16_t aPort,
   }
 
   nsCOMPtr<nsIDNSListener> listener =
-      new PendingSend(this, aPort, fallibleArray);
+      new PendingSend(this, aPort, std::move(fallibleArray));
 
   nsresult rv = ResolveHost(aHost, mOriginAttributes, listener);
   NS_ENSURE_SUCCESS(rv, rv);
diff --git a/netwerk/base/nsUDPSocket.h b/netwerk/base/nsUDPSocket.h
index 330f4a6486..b15b8b16dc 100644
--- a/netwerk/base/nsUDPSocket.h
+++ b/netwerk/base/nsUDPSocket.h
@@ -77,7 +77,7 @@ class nsUDPMessage : public nsIUDPMessage {
   NS_DECL_NSIUDPMESSAGE
 
   nsUDPMessage(NetAddr* aAddr, nsIOutputStream* aOutputStream,
-               FallibleTArray<uint8_t>& aData);
+               FallibleTArray<uint8_t>&& aData);
 
  private:
   virtual ~nsUDPMessage();
diff --git a/netwerk/build/components.conf b/netwerk/build/components.conf
index 5634bf36a9..a79b2dd2b6 100644
--- a/netwerk/build/components.conf
+++ b/netwerk/build/components.conf
@@ -17,17 +17,21 @@ Classes = [
         'headers': ['/netwerk/base/ArrayBufferInputStream.h'],
     },
     {
+        'js_name': 'loadContextInfo',
         'cid': '{62d4b190-3642-4450-b019-d1c1fba56025}',
         'contract_ids': ['@mozilla.org/load-context-info-factory;1'],
+        'interfaces': ['nsILoadContextInfoFactory'],
         'type': 'mozilla::net::LoadContextInfoFactory',
         'headers': ['mozilla/LoadContextInfo.h'],
     },
     {
+        'js_name': 'cache2',
         'cid': '{ea70b098-5014-4e21-aee1-75e6b2c4b8e0}',
         'contract_ids': [
             '@mozilla.org/netwerk/cache-storage-service;1',
             '@mozilla.org/network/cache-storage-service;1',
         ],
+        'interfaces': ['nsICacheStorageService'],
         'singleton': True,
         'type': 'mozilla::net::CacheStorageService',
         'headers': ['CacheStorageService.h'],
@@ -117,8 +121,10 @@ Classes = [
         'headers': ['/netwerk/base/nsDownloader.h'],
     },
     {
+        'js_name': 'eTLD',
         'cid': '{cb9abbae-66b6-4609-8594-5c4ff300888e}',
         'contract_ids': ['@mozilla.org/network/effective-tld-service;1'],
+        'interfaces': ['nsIEffectiveTLDService'],
         'singleton': True,
         'type': 'nsEffectiveTLDService',
         'headers': ['/netwerk/dns/nsEffectiveTLDService.h'],
@@ -181,11 +187,13 @@ Classes = [
         'headers': ['nsInputStreamPump.h'],
     },
     {
+        'js_name': 'io',
         'cid': '{9ac9e770-18bc-11d3-9337-00104ba0fd40}',
         'contract_ids': [
             '@mozilla.org/network/io-service;1',
             '@mozilla.org/network/util;1',
         ],
+        'interfaces': ['nsIIOService', 'nsISpeculativeConnect', 'nsINetUtil'],
         'singleton': True,
         'type': 'mozilla::net::nsIOService',
         'headers': ['/netwerk/base/nsIOService.h'],
@@ -548,11 +556,13 @@ Classes = [
 if defined('NECKO_COOKIES'):
     Classes += [
         {
+            'js_name': 'cookies',
             'cid': '{c375fa80-150f-11d6-a618-0010a401eb10}',
             'contract_ids': [
                 '@mozilla.org/cookieService;1',
                 '@mozilla.org/cookiemanager;1',
             ],
+            'interfaces': ['nsICookieManager'],
             'singleton': True,
             'type': 'nsICookieService',
             'constructor': 'nsCookieService::GetXPCOMSingleton',
diff --git a/netwerk/cache/nsDiskCacheDeviceSQL.cpp b/netwerk/cache/nsDiskCacheDeviceSQL.cpp
index 75d877b135..75287eb268 100644
--- a/netwerk/cache/nsDiskCacheDeviceSQL.cpp
+++ b/netwerk/cache/nsDiskCacheDeviceSQL.cpp
@@ -262,8 +262,7 @@ void nsOfflineCacheEvictionFunction::Apply() {
     return;
   }
 
-  appcachedetail::FileArray items;
-  items.SwapElements(*pitems);
+  appcachedetail::FileArray items = std::move(*pitems);
 
   for (int32_t i = 0; i < items.Count(); i++) {
     if (MOZ_LOG_TEST(gCacheLog, LogLevel::Debug)) {
@@ -2115,7 +2114,7 @@ nsresult nsOfflineCacheDevice::RunSimpleQuery(mozIStorageStatement* statement,
     NS_ENSURE_SUCCESS(rv, rv);
   }
 
-  values.SwapElements(valArray);
+  values = std::move(valArray);
   return NS_OK;
 }
 
diff --git a/netwerk/cache2/CacheIOThread.cpp b/netwerk/cache2/CacheIOThread.cpp
index 45b0e4e1f6..4223732e07 100644
--- a/netwerk/cache2/CacheIOThread.cpp
+++ b/netwerk/cache2/CacheIOThread.cpp
@@ -12,7 +12,7 @@
 #include "nsThreadManager.h"
 #include "nsThreadUtils.h"
 #include "mozilla/EventQueue.h"
-//#include "mozilla/IOInterposer.h"
+#include "mozilla/IOInterposer.h"
 #include "mozilla/ThreadEventQueue.h"
 #include "GeckoProfiler.h"
 
@@ -419,10 +419,10 @@ void CacheIOThread::ThreadFunc(void* aClosure) {
   // so causes leaks, see bug 1323100.
   NS_SetCurrentThreadName("Cache2 I/O");
 
-  //mozilla::IOInterposer::RegisterCurrentThread();
+  mozilla::IOInterposer::RegisterCurrentThread();
   CacheIOThread* thread = static_cast<CacheIOThread*>(aClosure);
   thread->ThreadFunc();
-  //mozilla::IOInterposer::UnregisterCurrentThread();
+  mozilla::IOInterposer::UnregisterCurrentThread();
 }
 
 void CacheIOThread::ThreadFunc() {
@@ -512,8 +512,7 @@ void CacheIOThread::ThreadFunc() {
 }
 
 void CacheIOThread::LoopOneLevel(uint32_t aLevel) {
-  EventQueue events;
-  events.SwapElements(mEventQueue[aLevel]);
+  EventQueue events = std::move(mEventQueue[aLevel]);
   EventQueue::size_type length = events.Length();
 
   mCurrentlyExecutingLevel = aLevel;
@@ -576,7 +575,7 @@ void CacheIOThread::LoopOneLevel(uint32_t aLevel) {
     // pretended earlier.
     events.AppendElements(std::move(mEventQueue[aLevel]));
     // And finally move everything back to the main queue.
-    events.SwapElements(mEventQueue[aLevel]);
+    mEventQueue[aLevel] = std::move(events);
   }
 }
 
diff --git a/netwerk/cache2/CacheIndexIterator.cpp b/netwerk/cache2/CacheIndexIterator.cpp
index 0c365c1f82..274b0bcc01 100644
--- a/netwerk/cache2/CacheIndexIterator.cpp
+++ b/netwerk/cache2/CacheIndexIterator.cpp
@@ -36,8 +36,7 @@ nsresult CacheIndexIterator::GetNextHash(SHA1Sum::Hash* aHash) {
     return mStatus;
   }
 
-  memcpy(aHash, mRecords[mRecords.Length() - 1]->mHash, sizeof(SHA1Sum::Hash));
-  mRecords.RemoveLastElement();
+  memcpy(aHash, mRecords.PopLastElement()->mHash, sizeof(SHA1Sum::Hash));
 
   return NS_OK;
 }
diff --git a/netwerk/cookie/nsCookieService.cpp b/netwerk/cookie/nsCookieService.cpp
index 1bdc0d995a..071a808533 100644
--- a/netwerk/cookie/nsCookieService.cpp
+++ b/netwerk/cookie/nsCookieService.cpp
@@ -4069,6 +4069,15 @@ nsAutoCString nsCookieService::GetPathFromURI(nsIURI* aHostURI) {
       path.Truncate(slash + 1);
     }
   }
+
+  // strip the right-most %x2F ("/") if the path doesn't contain only 1 '/'.
+  int32_t lastSlash = path.RFindChar('/');
+  int32_t firstSlash = path.FindChar('/');
+  if (lastSlash != firstSlash && lastSlash != kNotFound &&
+      lastSlash == (int32_t)(path.Length() - 1)) {
+    path.Truncate(lastSlash);
+  }
+
   return path;
 }
 
diff --git a/netwerk/protocol/about/nsAboutCacheEntry.cpp b/netwerk/protocol/about/nsAboutCacheEntry.cpp
index f86264511e..49f727c141 100644
--- a/netwerk/protocol/about/nsAboutCacheEntry.cpp
+++ b/netwerk/protocol/about/nsAboutCacheEntry.cpp
@@ -141,6 +141,8 @@ nsresult nsAboutCacheEntry::Channel::GetContentStream(nsIURI* uri,
       "<!DOCTYPE html>\n"
       "<html>\n"
       "<head>\n"
+      "  <meta http-equiv=\"Content-Security-Policy\" content=\"default-src "
+      "chrome:\" />\n"
       "  <title>Cache entry information</title>\n"
       "  <link rel=\"stylesheet\" "
       "href=\"chrome://global/skin/about.css\" type=\"text/css\"/>\n"
diff --git a/netwerk/protocol/http/DelayHttpChannelQueue.cpp b/netwerk/protocol/http/DelayHttpChannelQueue.cpp
index 79945a03c7..8b1f5bf32f 100644
--- a/netwerk/protocol/http/DelayHttpChannelQueue.cpp
+++ b/netwerk/protocol/http/DelayHttpChannelQueue.cpp
@@ -100,8 +100,7 @@ void DelayHttpChannelQueue::FireQueue() {
   // TODO: get this from the DOM clock?
   TimeStamp ts = TimeStamp::Now();
 
-  FallibleTArray<RefPtr<nsHttpChannel>> queue;
-  queue.SwapElements(mQueue);
+  FallibleTArray<RefPtr<nsHttpChannel>> queue = std::move(mQueue);
 
   for (RefPtr<nsHttpChannel>& channel : queue) {
     channel->AsyncOpenFinal(ts);
diff --git a/netwerk/protocol/http/HttpBaseChannel.cpp b/netwerk/protocol/http/HttpBaseChannel.cpp
index 1f14987b82..f42be75507 100644
--- a/netwerk/protocol/http/HttpBaseChannel.cpp
+++ b/netwerk/protocol/http/HttpBaseChannel.cpp
@@ -2247,8 +2247,8 @@ HttpBaseChannel::TakeAllSecurityMessages(
         do_CreateInstance(NS_SECURITY_CONSOLE_MESSAGE_CONTRACTID, &rv);
     NS_ENSURE_SUCCESS(rv, rv);
 
-    message->SetTag(pair.first());
-    message->SetCategory(pair.second());
+    message->SetTag(pair.first);
+    message->SetCategory(pair.second);
     aMessages.AppendElement(message);
   }
 
@@ -2276,7 +2276,7 @@ nsresult HttpBaseChannel::AddSecurityMessage(
   // nsSecurityConsoleMessage is not thread-safe refcounted.
   // Delay the object construction until requested.
   // See TakeAllSecurityMessages()
-  Pair<nsString, nsString> pair(aMessageTag, aMessageCategory);
+  std::pair<nsString, nsString> pair(aMessageTag, aMessageCategory);
   mSecurityConsoleMessages.AppendElement(std::move(pair));
 
   nsCOMPtr<nsIConsoleService> console(
diff --git a/netwerk/protocol/http/HttpBaseChannel.h b/netwerk/protocol/http/HttpBaseChannel.h
index 3985061116..4ec0077ad6 100644
--- a/netwerk/protocol/http/HttpBaseChannel.h
+++ b/netwerk/protocol/http/HttpBaseChannel.h
@@ -621,7 +621,7 @@ class HttpBaseChannel : public nsHashPropertyBag,
   NetAddr mSelfAddr;
   NetAddr mPeerAddr;
 
-  nsTArray<Pair<nsString, nsString>> mSecurityConsoleMessages;
+  nsTArray<std::pair<nsString, nsString>> mSecurityConsoleMessages;
   nsTArray<nsCString> mUnsafeHeaders;
 
   // A time value equal to the starting time of the fetch that initiates the
diff --git a/netwerk/protocol/http/HttpChannelChild.cpp b/netwerk/protocol/http/HttpChannelChild.cpp
index c8961c9781..44adfdcaed 100644
--- a/netwerk/protocol/http/HttpChannelChild.cpp
+++ b/netwerk/protocol/http/HttpChannelChild.cpp
@@ -1109,7 +1109,7 @@ void HttpChannelChild::OnStopRequest(
   mCacheReadEnd = timing.cacheReadEnd;
 
 #ifdef MOZ_GECKO_PROFILER
-  if (profiler_is_active()) {
+  if (profiler_can_accept_markers()) {
     int32_t priority = PRIORITY_NORMAL;
     GetPriority(&priority);
     profiler_add_network_marker(mURI, priority, mChannelId,
diff --git a/netwerk/protocol/http/nsHttpChannel.cpp b/netwerk/protocol/http/nsHttpChannel.cpp
index 9efdb260ac..8ff2f23170 100644
--- a/netwerk/protocol/http/nsHttpChannel.cpp
+++ b/netwerk/protocol/http/nsHttpChannel.cpp
@@ -5762,7 +5762,7 @@ nsresult nsHttpChannel::ContinueProcessRedirectionAfterFallback(nsresult rv) {
   }
 
 #ifdef MOZ_GECKO_PROFILER
-  if (profiler_is_active()) {
+  if (profiler_can_accept_markers()) {
     int32_t priority = PRIORITY_NORMAL;
     GetPriority(&priority);
 
@@ -6203,7 +6203,7 @@ nsHttpChannel::AsyncOpen(nsIStreamListener* aListener) {
 #ifdef MOZ_GECKO_PROFILER
   mLastStatusReported =
       TimeStamp::Now();  // in case we enable the profiler after AsyncOpen()
-  if (profiler_is_active()) {
+  if (profiler_can_accept_markers()) {
     profiler_add_network_marker(
         mURI, mPriority, mChannelId, NetworkLoadType::LOAD_START,
         mChannelCreationTimestamp, mLastStatusReported, 0, mCacheDisposition);
@@ -8001,7 +8001,7 @@ nsresult nsHttpChannel::ContinueOnStopRequest(nsresult aStatus, bool aIsFromNet,
   MaybeReportTimingData();
 
 #ifdef MOZ_GECKO_PROFILER
-  if (profiler_is_active() && !mRedirectURI) {
+  if (profiler_can_accept_markers() && !mRedirectURI) {
     // Don't include this if we already redirected
     // These do allocations/frees/etc; avoid if not active
     nsCOMPtr<nsIURI> uri;
@@ -8909,10 +8909,10 @@ void nsHttpChannel::PushRedirectAsyncFunc(nsContinueRedirectionFunc func) {
 }
 
 void nsHttpChannel::PopRedirectAsyncFunc(nsContinueRedirectionFunc func) {
-  MOZ_ASSERT(func == mRedirectFuncStack[mRedirectFuncStack.Length() - 1],
+  MOZ_ASSERT(func == mRedirectFuncStack.LastElement(),
              "Trying to pop wrong method from redirect async stack!");
 
-  mRedirectFuncStack.TruncateLength(mRedirectFuncStack.Length() - 1);
+  mRedirectFuncStack.RemoveLastElement();
 }
 
 //-----------------------------------------------------------------------------
diff --git a/netwerk/protocol/http/nsHttpConnectionMgr.cpp b/netwerk/protocol/http/nsHttpConnectionMgr.cpp
index a0a464f659..cbbba8f13e 100644
--- a/netwerk/protocol/http/nsHttpConnectionMgr.cpp
+++ b/netwerk/protocol/http/nsHttpConnectionMgr.cpp
@@ -699,7 +699,7 @@ nsHttpConnection* nsHttpConnectionMgr::FindCoalescableConnectionByHashKey(
         listOfWeakConns->Elements()[j] =
             listOfWeakConns->Elements()[listLen - 1];
       }
-      listOfWeakConns->RemoveElementAt(listLen - 1);
+      listOfWeakConns->RemoveLastElement();
       MOZ_ASSERT(listOfWeakConns->Length() == listLen - 1);
       listLen--;
       continue;  // without adjusting iterator
diff --git a/netwerk/protocol/res/ExtensionProtocolHandler.cpp b/netwerk/protocol/res/ExtensionProtocolHandler.cpp
index f7eb0e76c6..d7a82fbf59 100644
--- a/netwerk/protocol/res/ExtensionProtocolHandler.cpp
+++ b/netwerk/protocol/res/ExtensionProtocolHandler.cpp
@@ -877,7 +877,7 @@ static void NewSimpleChannel(nsIURI* aURI, nsILoadInfo* aLoadinfo,
         nsresult rv = origChannel->AsyncOpen(listener);
         if (NS_FAILED(rv)) {
           simpleChannel->Cancel(NS_BINDING_ABORTED);
-          return RequestOrReason(rv);
+          return Err(rv);
         }
         return RequestOrReason(origChannel);
       });
diff --git a/netwerk/test/unit/xpcshell.ini b/netwerk/test/unit/xpcshell.ini
index e8bfc8bae4..a4c3ee63b4 100644
--- a/netwerk/test/unit/xpcshell.ini
+++ b/netwerk/test/unit/xpcshell.ini
@@ -435,7 +435,7 @@ skip-if = os == "android"
 [test_substituting_protocol_handler.js]
 [test_proxyconnect.js]
 [test_captive_portal_service.js]
-skip-if = os == "android" # CP service is disabled on Android
+skip-if = os == "android" || (os == "mac" && debug) # CP service is disabled on Android, macosx1014/debug due to 1564534
 run-sequentially = node server exceptions dont replay well
 [test_esni_dns_fetch.js]
 # http2-using tests require node available
diff --git a/other-licenses/nsis/Contrib/CityHash/cityhash/city.h b/other-licenses/nsis/Contrib/CityHash/cityhash/city.h
index f0f569c54b..01d47e4c1f 100644
--- a/other-licenses/nsis/Contrib/CityHash/cityhash/city.h
+++ b/other-licenses/nsis/Contrib/CityHash/cityhash/city.h
@@ -51,20 +51,11 @@ typedef uint32_t uint32;
 typedef uint64_t uint64;
 
 #ifdef __cplusplus
-// The standard <utility> header doesn't compile, apparently it conflicts
-// with... some Mozilla something or other. But all that's used from it
-// is std::pair, so we can just replace that with mozilla::Pair.
-#ifndef MOZILLA_CLIENT
+
 #include <utility>
 typedef std::pair<uint64, uint64> uint128;
 inline uint64 Uint128Low64(const uint128& x) { return x.first; }
 inline uint64 Uint128High64(const uint128& x) { return x.second; }
-#else
-#include "mozilla/Pair.h"
-typedef mozilla::Pair<uint64, uint64> uint128;
-inline uint64 Uint128Low64(const uint128& x) { return x.first(); }
-inline uint64 Uint128High64(const uint128& x) { return x.second(); }
-#endif
 
 extern "C" {
 #endif
diff --git a/python/mozbuild/mozbuild/mach_commands.py b/python/mozbuild/mozbuild/mach_commands.py
index ab147471b4..aae2215e63 100644
--- a/python/mozbuild/mozbuild/mach_commands.py
+++ b/python/mozbuild/mozbuild/mach_commands.py
@@ -621,6 +621,9 @@ class GTestCommands(MachCommandBase):
     @CommandArgument('--libxul',
                      dest='libxul_path',
                      help='(Android only) Path to gtest libxul.so.')
+    @CommandArgument('--enable-webrender', action='store_true',
+                     default=False, dest='enable_webrender',
+                     help='Enable the WebRender compositor in Gecko.')
     @CommandArgumentGroup('debugging')
     @CommandArgument('--debug', action='store_true', group='debugging',
                      help='Enable the debugger. Not specifying a --debugger option will result in '
@@ -633,7 +636,7 @@ class GTestCommands(MachCommandBase):
                      'split as the Bourne shell would.')
     def gtest(self, shuffle, jobs, gtest_filter, tbpl_parser,
               package, adb_path, device_serial, remote_test_root, libxul_path,
-              debug, debugger, debugger_args):
+              enable_webrender, debug, debugger, debugger_args):
 
         # We lazy build gtest because it's slow to link
         try:
@@ -670,7 +673,8 @@ class GTestCommands(MachCommandBase):
                 print("--debug options are not supported on Android and will be ignored")
             return self.android_gtest(cwd, shuffle, gtest_filter,
                                       package, adb_path, device_serial,
-                                      remote_test_root, libxul_path)
+                                      remote_test_root, libxul_path,
+                                      enable_webrender)
 
         if package or adb_path or device_serial or remote_test_root or libxul_path:
             print("One or more Android-only options will be ignored")
@@ -708,6 +712,12 @@ class GTestCommands(MachCommandBase):
         if tbpl_parser:
             gtest_env[b"MOZ_TBPL_PARSER"] = b"True"
 
+        if enable_webrender:
+            gtest_env[b"MOZ_WEBRENDER"] = b"1"
+            gtest_env[b"MOZ_ACCELERATED"] = b"1"
+        else:
+            gtest_env[b"MOZ_WEBRENDER"] = b"0"
+
         if jobs == 1:
             return self.run_process(args=args,
                                     append_env=gtest_env,
@@ -749,7 +759,8 @@ class GTestCommands(MachCommandBase):
         return exit_code
 
     def android_gtest(self, test_dir, shuffle, gtest_filter,
-                      package, adb_path, device_serial, remote_test_root, libxul_path):
+                      package, adb_path, device_serial, remote_test_root, libxul_path,
+                      enable_webrender):
         # setup logging for mozrunner
         from mozlog.commandline import setup_logging
         format_args = {'level': self._mach_context.settings['test']['level']}
@@ -774,7 +785,7 @@ class GTestCommands(MachCommandBase):
         import remotegtests
         tester = remotegtests.RemoteGTests()
         tester.run_gtest(test_dir, shuffle, gtest_filter, package, adb_path, device_serial,
-                         remote_test_root, libxul_path, None)
+                         remote_test_root, libxul_path, None, enable_webrender)
         tester.cleanup()
 
         return 0
diff --git a/security/sandbox/linux/Sandbox.cpp b/security/sandbox/linux/Sandbox.cpp
index b6f8e5782f..876b5632ee 100644
--- a/security/sandbox/linux/Sandbox.cpp
+++ b/security/sandbox/linux/Sandbox.cpp
@@ -638,9 +638,11 @@ void SetMediaPluginSandbox(const char* aFilePath) {
   auto files = new SandboxOpenedFiles();
   files->Add(std::move(plugin));
   files->Add("/dev/urandom", true);
+  files->Add("/etc/ld.so.cache");  // Needed for NSS in clearkey.
   files->Add("/sys/devices/system/cpu/cpu0/tsc_freq_khz");
   files->Add("/sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_max_freq");
   files->Add("/proc/cpuinfo");  // Info also available via CPUID instruction.
+  files->Add("/proc/sys/crypto/fips_enabled");  // Needed for NSS in clearkey.
 #ifdef __i386__
   files->Add("/proc/self/auxv");  // Info also in process's address space.
 #endif
diff --git a/security/sandbox/linux/SandboxFilter.cpp b/security/sandbox/linux/SandboxFilter.cpp
index 43ac0b01d7..aeaa96ac98 100644
--- a/security/sandbox/linux/SandboxFilter.cpp
+++ b/security/sandbox/linux/SandboxFilter.cpp
@@ -1370,7 +1370,13 @@ class GMPSandboxPolicy : public SandboxPolicyCommon {
         return Trap(OpenTrap, mFiles);
 
       case __NR_brk:
+      // Because Firefox on glibc resorts to the fallback implementation
+      // mentioned in bug 1576006, we must explicitly allow the get*id()
+      // functions in order to use NSS in the clearkey CDM.
+      CASES_FOR_getuid:
+      CASES_FOR_getgid:
       CASES_FOR_geteuid:
+      CASES_FOR_getegid:
         return Allow();
       case __NR_sched_get_priority_min:
       case __NR_sched_get_priority_max:
diff --git a/security/sandbox/win/src/remotesandboxbroker/RemoteSandboxBrokerProcessParent.cpp b/security/sandbox/win/src/remotesandboxbroker/RemoteSandboxBrokerProcessParent.cpp
index c4fd7a516c..8895b93b4f 100644
--- a/security/sandbox/win/src/remotesandboxbroker/RemoteSandboxBrokerProcessParent.cpp
+++ b/security/sandbox/win/src/remotesandboxbroker/RemoteSandboxBrokerProcessParent.cpp
@@ -6,6 +6,8 @@
 #include <windows.h>
 
 using mozilla::ipc::GeckoChildProcessHost;
+using mozilla::ipc::LaunchError;
+using mozilla::ipc::ProcessHandlePromise;
 
 namespace mozilla {
 
@@ -18,11 +20,10 @@ RemoteSandboxBrokerProcessParent::~RemoteSandboxBrokerProcessParent() {
   MOZ_COUNT_DTOR(RemoteSandboxBrokerProcessParent);
 }
 
-RefPtr<RemoteSandboxBrokerProcessParent::HandlePromise>
+RefPtr<ProcessHandlePromise>
 RemoteSandboxBrokerProcessParent::AsyncLaunch() {
   if (!GeckoChildProcessHost::AsyncLaunch()) {
-    return HandlePromise::CreateAndReject(GeckoChildProcessHost::LaunchError{},
-                                          __func__);
+    return ProcessHandlePromise::CreateAndReject(LaunchError{}, __func__);
   }
   return WhenProcessHandleReady();
 }
diff --git a/security/sandbox/win/src/remotesandboxbroker/RemoteSandboxBrokerProcessParent.h b/security/sandbox/win/src/remotesandboxbroker/RemoteSandboxBrokerProcessParent.h
index c208fc935b..c8e27a90ab 100644
--- a/security/sandbox/win/src/remotesandboxbroker/RemoteSandboxBrokerProcessParent.h
+++ b/security/sandbox/win/src/remotesandboxbroker/RemoteSandboxBrokerProcessParent.h
@@ -19,14 +19,9 @@ namespace mozilla {
 class RemoteSandboxBrokerProcessParent final
     : public mozilla::ipc::GeckoChildProcessHost {
  public:
-  using LaunchError = GeckoChildProcessHost::LaunchError;
-  using LaunchPromise = GeckoChildProcessHost::LaunchPromise<bool>;
-
   RemoteSandboxBrokerProcessParent();
 
-  using GeckoChildProcessHost::HandlePromise;
-
-  RefPtr<HandlePromise> AsyncLaunch();
+  RefPtr<ipc::ProcessHandlePromise> AsyncLaunch();
 
   bool CanShutdown() override { return true; }
 
diff --git a/services/sync/modules/telemetry.js b/services/sync/modules/telemetry.js
index 2fdc0d8ce3..6187fb2765 100644
--- a/services/sync/modules/telemetry.js
+++ b/services/sync/modules/telemetry.js
@@ -893,5 +893,4 @@ class SyncTelemetryImpl {
   }
 }
 
-/* global SyncTelemetry */
 var SyncTelemetry = new SyncTelemetryImpl(ENGINES);
diff --git a/services/sync/tests/unit/test_password_store.js b/services/sync/tests/unit/test_password_store.js
index bc45760219..97ff6d0f13 100644
--- a/services/sync/tests/unit/test_password_store.js
+++ b/services/sync/tests/unit/test_password_store.js
@@ -292,7 +292,7 @@ async function test_apply_same_record_with_different_times() {
     true,
     true
   );
-  /* eslint-enable no-unsed-vars */
+  /* eslint-enable no-unused-vars */
 }
 
 async function test_LoginRec_toString(store, recordData) {
diff --git a/servo/components/malloc_size_of/Cargo.toml b/servo/components/malloc_size_of/Cargo.toml
index 77915f1fa6..423934be81 100644
--- a/servo/components/malloc_size_of/Cargo.toml
+++ b/servo/components/malloc_size_of/Cargo.toml
@@ -31,7 +31,7 @@ accountable-refcell = { version = "0.2.0", optional = true }
 app_units = "0.7"
 content-security-policy = { version = "0.4.0", features = ["serde"], optional = true }
 crossbeam-channel = { version = "0.4", optional = true }
-cssparser = "0.27"
+cssparser = "0.28"
 euclid = "0.20"
 hashglobe = { path = "../hashglobe" }
 hyper = { version = "0.12", optional = true }
diff --git a/servo/components/selectors/Cargo.toml b/servo/components/selectors/Cargo.toml
index db42b16ec3..3a8517c919 100644
--- a/servo/components/selectors/Cargo.toml
+++ b/servo/components/selectors/Cargo.toml
@@ -20,7 +20,7 @@ bench = []
 [dependencies]
 bitflags = "1.0"
 matches = "0.1"
-cssparser = "0.27"
+cssparser = "0.28"
 derive_more = "0.99"
 fxhash = "0.2"
 log = "0.4"
diff --git a/servo/components/style/Cargo.toml b/servo/components/style/Cargo.toml
index ad37a6a5f2..f138f71753 100644
--- a/servo/components/style/Cargo.toml
+++ b/servo/components/style/Cargo.toml
@@ -31,7 +31,7 @@ arrayvec = "0.5"
 atomic_refcell = "0.1"
 bitflags = "1.0"
 byteorder = "1.0"
-cssparser = "0.27"
+cssparser = "0.28"
 derive_more = "0.99"
 new_debug_unreachable = "1.0"
 encoding_rs = {version = "0.8", optional = true}
diff --git a/servo/components/style/stylesheets/font_feature_values_rule.rs b/servo/components/style/stylesheets/font_feature_values_rule.rs
index 74900f96ba..8417497acb 100644
--- a/servo/components/style/stylesheets/font_feature_values_rule.rs
+++ b/servo/components/style/stylesheets/font_feature_values_rule.rs
@@ -20,7 +20,7 @@ use crate::values::serialize_atom_identifier;
 use crate::Atom;
 use cssparser::{AtRuleParser, AtRuleType, BasicParseErrorKind, CowRcStr};
 use cssparser::{DeclarationListParser, DeclarationParser, Parser};
-use cssparser::{QualifiedRuleParser, RuleListParser, SourceLocation, Token};
+use cssparser::{QualifiedRuleParser, RuleListParser, SourceLocation, ParserState, Token};
 use std::fmt::{self, Write};
 use style_traits::{CssWriter, ParseError, StyleParseErrorKind, ToCss};
 
@@ -413,7 +413,7 @@ macro_rules! font_feature_values_blocks {
             fn parse_block<'t>(
                 &mut self,
                 prelude: BlockType,
-                _location: SourceLocation,
+                _: &ParserState,
                 input: &mut Parser<'i, 't>
             ) -> Result<Self::AtRule, ParseError<'i>> {
                 debug_assert_eq!(self.context.rule_type(), CssRuleType::FontFeatureValues);
diff --git a/servo/components/style/stylesheets/keyframes_rule.rs b/servo/components/style/stylesheets/keyframes_rule.rs
index 5861f38f66..7da8d8f306 100644
--- a/servo/components/style/stylesheets/keyframes_rule.rs
+++ b/servo/components/style/stylesheets/keyframes_rule.rs
@@ -17,7 +17,7 @@ use crate::str::CssStringWriter;
 use crate::stylesheets::rule_parser::VendorPrefix;
 use crate::stylesheets::{CssRuleType, StylesheetContents};
 use crate::values::{serialize_percentage, KeyframesName};
-use cssparser::{parse_one_rule, DeclarationListParser, DeclarationParser, SourceLocation, Token};
+use cssparser::{parse_one_rule, DeclarationListParser, DeclarationParser, ParserState, SourceLocation, Token};
 use cssparser::{AtRuleParser, CowRcStr, Parser, ParserInput, QualifiedRuleParser, RuleListParser};
 use servo_arc::Arc;
 use std::fmt::{self, Write};
@@ -532,7 +532,7 @@ impl<'a, 'i> QualifiedRuleParser<'i> for KeyframeListParser<'a> {
     fn parse_block<'t>(
         &mut self,
         selector: Self::Prelude,
-        source_location: SourceLocation,
+        start: &ParserState,
         input: &mut Parser<'i, 't>,
     ) -> Result<Self::QualifiedRule, ParseError<'i>> {
         let context = ParserContext::new_with_rule_type(
@@ -565,7 +565,7 @@ impl<'a, 'i> QualifiedRuleParser<'i> for KeyframeListParser<'a> {
         Ok(Arc::new(self.shared_lock.wrap(Keyframe {
             selector,
             block: Arc::new(self.shared_lock.wrap(block)),
-            source_location,
+            source_location: start.source_location(),
         })))
     }
 }
diff --git a/servo/components/style/stylesheets/rule_parser.rs b/servo/components/style/stylesheets/rule_parser.rs
index 74425afafc..46af02eff6 100644
--- a/servo/components/style/stylesheets/rule_parser.rs
+++ b/servo/components/style/stylesheets/rule_parser.rs
@@ -27,7 +27,7 @@ use crate::values::computed::font::FamilyName;
 use crate::values::{CssUrl, CustomIdent, KeyframesName};
 use crate::{Namespace, Prefix};
 use cssparser::{AtRuleParser, AtRuleType, Parser, QualifiedRuleParser, RuleListParser};
-use cssparser::{BasicParseError, BasicParseErrorKind, CowRcStr, SourceLocation};
+use cssparser::{BasicParseError, BasicParseErrorKind, CowRcStr, ParserState};
 use selectors::SelectorList;
 use servo_arc::Arc;
 use style_traits::{ParseError, StyleParseErrorKind};
@@ -251,10 +251,10 @@ impl<'a, 'i> AtRuleParser<'i> for TopLevelRuleParser<'a> {
     fn parse_block<'t>(
         &mut self,
         prelude: AtRuleBlockPrelude,
-        location: SourceLocation,
+        start: &ParserState,
         input: &mut Parser<'i, 't>,
     ) -> Result<CssRule, ParseError<'i>> {
-        AtRuleParser::parse_block(&mut self.nested(), prelude, location, input).map(|rule| {
+        AtRuleParser::parse_block(&mut self.nested(), prelude, start, input).map(|rule| {
             self.state = State::Body;
             rule
         })
@@ -264,8 +264,8 @@ impl<'a, 'i> AtRuleParser<'i> for TopLevelRuleParser<'a> {
     fn rule_without_block(
         &mut self,
         prelude: AtRuleNonBlockPrelude,
-        source_location: SourceLocation,
-    ) -> CssRule {
+        start: &ParserState,
+    ) -> Self::AtRule {
         match prelude {
             AtRuleNonBlockPrelude::Import(url, media) => {
                 let loader = self
@@ -274,7 +274,7 @@ impl<'a, 'i> AtRuleParser<'i> for TopLevelRuleParser<'a> {
 
                 let import_rule = loader.request_stylesheet(
                     url,
-                    source_location,
+                    start.source_location(),
                     &self.context,
                     &self.shared_lock,
                     media,
@@ -296,7 +296,7 @@ impl<'a, 'i> AtRuleParser<'i> for TopLevelRuleParser<'a> {
                 CssRule::Namespace(Arc::new(self.shared_lock.wrap(NamespaceRule {
                     prefix,
                     url,
-                    source_location,
+                    source_location: start.source_location(),
                 })))
             },
         }
@@ -324,10 +324,10 @@ impl<'a, 'i> QualifiedRuleParser<'i> for TopLevelRuleParser<'a> {
     fn parse_block<'t>(
         &mut self,
         prelude: Self::Prelude,
-        location: SourceLocation,
+        start: &ParserState,
         input: &mut Parser<'i, 't>,
     ) -> Result<CssRule, ParseError<'i>> {
-        QualifiedRuleParser::parse_block(&mut self.nested(), prelude, location, input).map(
+        QualifiedRuleParser::parse_block(&mut self.nested(), prelude, start, input).map(
             |result| {
                 self.state = State::Body;
                 result
@@ -461,7 +461,7 @@ impl<'a, 'b, 'i> AtRuleParser<'i> for NestedRuleParser<'a, 'b> {
     fn parse_block<'t>(
         &mut self,
         prelude: AtRuleBlockPrelude,
-        source_location: SourceLocation,
+        start: &ParserState,
         input: &mut Parser<'i, 't>,
     ) -> Result<CssRule, ParseError<'i>> {
         match prelude {
@@ -473,7 +473,7 @@ impl<'a, 'b, 'i> AtRuleParser<'i> for NestedRuleParser<'a, 'b> {
                 );
 
                 Ok(CssRule::FontFace(Arc::new(self.shared_lock.wrap(
-                    parse_font_face_block(&context, input, source_location).into(),
+                    parse_font_face_block(&context, input, start.source_location()).into(),
                 ))))
             },
             AtRuleBlockPrelude::FontFeatureValues(family_names) => {
@@ -484,7 +484,7 @@ impl<'a, 'b, 'i> AtRuleParser<'i> for NestedRuleParser<'a, 'b> {
                 );
 
                 Ok(CssRule::FontFeatureValues(Arc::new(self.shared_lock.wrap(
-                    FontFeatureValuesRule::parse(&context, input, family_names, source_location),
+                    FontFeatureValuesRule::parse(&context, input, family_names, start.source_location()),
                 ))))
             },
             AtRuleBlockPrelude::CounterStyle(name) => {
@@ -495,14 +495,14 @@ impl<'a, 'b, 'i> AtRuleParser<'i> for NestedRuleParser<'a, 'b> {
                 );
 
                 Ok(CssRule::CounterStyle(Arc::new(self.shared_lock.wrap(
-                    parse_counter_style_body(name, &context, input, source_location)?.into(),
+                    parse_counter_style_body(name, &context, input, start.source_location())?.into(),
                 ))))
             },
             AtRuleBlockPrelude::Media(media_queries) => {
                 Ok(CssRule::Media(Arc::new(self.shared_lock.wrap(MediaRule {
                     media_queries,
                     rules: self.parse_nested_rules(input, CssRuleType::Media),
-                    source_location,
+                    source_location: start.source_location(),
                 }))))
             },
             AtRuleBlockPrelude::Supports(condition) => {
@@ -518,7 +518,7 @@ impl<'a, 'b, 'i> AtRuleParser<'i> for NestedRuleParser<'a, 'b> {
                         condition,
                         rules: self.parse_nested_rules(input, CssRuleType::Supports),
                         enabled,
-                        source_location,
+                        source_location: start.source_location(),
                     },
                 ))))
             },
@@ -545,7 +545,7 @@ impl<'a, 'b, 'i> AtRuleParser<'i> for NestedRuleParser<'a, 'b> {
                         name,
                         keyframes: parse_keyframe_list(&context, input, self.shared_lock),
                         vendor_prefix,
-                        source_location,
+                        source_location: start.source_location(),
                     },
                 ))))
             },
@@ -559,7 +559,7 @@ impl<'a, 'b, 'i> AtRuleParser<'i> for NestedRuleParser<'a, 'b> {
                 let declarations = parse_property_declaration_list(&context, input, None);
                 Ok(CssRule::Page(Arc::new(self.shared_lock.wrap(PageRule {
                     block: Arc::new(self.shared_lock.wrap(declarations)),
-                    source_location,
+                    source_location: start.source_location(),
                 }))))
             },
             AtRuleBlockPrelude::Document(condition) => {
@@ -570,7 +570,7 @@ impl<'a, 'b, 'i> AtRuleParser<'i> for NestedRuleParser<'a, 'b> {
                     DocumentRule {
                         condition,
                         rules: self.parse_nested_rules(input, CssRuleType::Document),
-                        source_location,
+                        source_location: start.source_location(),
                     },
                 ))))
             },
@@ -598,7 +598,7 @@ impl<'a, 'b, 'i> QualifiedRuleParser<'i> for NestedRuleParser<'a, 'b> {
     fn parse_block<'t>(
         &mut self,
         selectors: Self::Prelude,
-        source_location: SourceLocation,
+        start: &ParserState,
         input: &mut Parser<'i, 't>,
     ) -> Result<CssRule, ParseError<'i>> {
         let context =
@@ -609,7 +609,7 @@ impl<'a, 'b, 'i> QualifiedRuleParser<'i> for NestedRuleParser<'a, 'b> {
         Ok(CssRule::Style(Arc::new(self.shared_lock.wrap(StyleRule {
             selectors,
             block,
-            source_location,
+            source_location: start.source_location(),
         }))))
     }
 }
diff --git a/servo/components/style_traits/Cargo.toml b/servo/components/style_traits/Cargo.toml
index 50e93ab25e..02bee7d899 100644
--- a/servo/components/style_traits/Cargo.toml
+++ b/servo/components/style_traits/Cargo.toml
@@ -16,7 +16,7 @@ gecko = []
 [dependencies]
 app_units = "0.7"
 bitflags = "1.0"
-cssparser = "0.27"
+cssparser = "0.28"
 euclid = "0.20"
 lazy_static = "1"
 malloc_size_of = { path = "../malloc_size_of" }
diff --git a/servo/components/to_shmem/Cargo.toml b/servo/components/to_shmem/Cargo.toml
index 76be7671da..6027d2670e 100644
--- a/servo/components/to_shmem/Cargo.toml
+++ b/servo/components/to_shmem/Cargo.toml
@@ -14,7 +14,7 @@ servo = ["cssparser/serde", "string_cache"]
 gecko = []
 
 [dependencies]
-cssparser = "0.27"
+cssparser = "0.28"
 servo_arc = { path = "../servo_arc" }
 smallbitvec = "2.1.1"
 smallvec = "1.0"
diff --git a/servo/ports/geckolib/Cargo.toml b/servo/ports/geckolib/Cargo.toml
index e188dbd179..fb4374f90d 100644
--- a/servo/ports/geckolib/Cargo.toml
+++ b/servo/ports/geckolib/Cargo.toml
@@ -15,7 +15,7 @@ gecko_profiler = ["style/gecko_profiler"]
 [dependencies]
 atomic_refcell = "0.1"
 bincode = "1.0"
-cssparser = "0.27"
+cssparser = "0.28"
 cstr = "0.1.2"
 libc = "0.2"
 log = {version = "0.4", features = ["release_max_level_info"]}
diff --git a/servo/ports/geckolib/tests/Cargo.toml b/servo/ports/geckolib/tests/Cargo.toml
index 613b8887f1..adee8ea04c 100644
--- a/servo/ports/geckolib/tests/Cargo.toml
+++ b/servo/ports/geckolib/tests/Cargo.toml
@@ -11,7 +11,7 @@ doctest = false
 
 [dependencies]
 atomic_refcell = "0.1"
-cssparser = "0.27"
+cssparser = "0.28"
 cstr = "0.1.2"
 env_logger = { version = "0.6", default-features = false }
 geckoservo = {path = "../../../ports/geckolib"}
diff --git a/servo/tests/unit/style/Cargo.toml b/servo/tests/unit/style/Cargo.toml
index f9dfb3b9d0..607fde7f10 100644
--- a/servo/tests/unit/style/Cargo.toml
+++ b/servo/tests/unit/style/Cargo.toml
@@ -12,7 +12,7 @@ doctest = false
 [dependencies]
 byteorder = "1.0"
 app_units = "0.7"
-cssparser = "0.27"
+cssparser = "0.28"
 euclid = "0.20"
 html5ever = "0.22"
 parking_lot = "0.10"
diff --git a/startupcache/StartupCache.cpp b/startupcache/StartupCache.cpp
index 714b3862c9..b734943711 100644
--- a/startupcache/StartupCache.cpp
+++ b/startupcache/StartupCache.cpp
@@ -4,7 +4,7 @@
 
 #include "prio.h"
 #include "PLDHashTable.h"
-//#include "mozilla/IOInterposer.h"
+#include "mozilla/IOInterposer.h"
 #include "mozilla/MemoryReporting.h"
 #include "mozilla/scache/StartupCache.h"
 
@@ -457,7 +457,7 @@ void StartupCache::WaitOnWriteThread() {
 void StartupCache::ThreadedWrite(void* aClosure) {
   AUTO_PROFILER_REGISTER_THREAD("StartupCache");
   NS_SetCurrentThreadName("StartupCache");
-  //mozilla::IOInterposer::RegisterCurrentThread();
+  mozilla::IOInterposer::RegisterCurrentThread();
   /*
    * It is safe to use the pointer passed in aClosure to reference the
    * StartupCache object because the thread's lifetime is tightly coupled to
@@ -467,7 +467,7 @@ void StartupCache::ThreadedWrite(void* aClosure) {
    */
   StartupCache* startupCacheObj = static_cast<StartupCache*>(aClosure);
   startupCacheObj->WriteToDisk();
-  //mozilla::IOInterposer::UnregisterCurrentThread();
+  mozilla::IOInterposer::UnregisterCurrentThread();
 }
 
 /*
diff --git a/storage/TelemetryVFS.cpp b/storage/TelemetryVFS.cpp
index 2de45696b9..4918b20389 100644
--- a/storage/TelemetryVFS.cpp
+++ b/storage/TelemetryVFS.cpp
@@ -11,9 +11,13 @@
 #include "mozilla/dom/quota/QuotaManager.h"
 #include "mozilla/dom/quota/QuotaObject.h"
 #include "mozilla/net/IOActivityMonitor.h"
-//#include "mozilla/IOInterposer.h"
+#include "mozilla/IOInterposer.h"
 #include "nsEscape.h"
 
+#ifdef XP_WIN
+#  include "mozilla/StaticPrefs_dom.h"
+#endif
+
 // The last VFS version for which this file has been updated.
 #define LAST_KNOWN_VFS_VERSION 3
 
@@ -85,8 +89,8 @@ class IOThreadAutoTimer {
    * either "sqlite-mainthread" or "sqlite-otherthread".
    */
   explicit IOThreadAutoTimer(
-      Telemetry::HistogramID aId)//,
-      //IOInterposeObserver::Operation aOp = IOInterposeObserver::OpNone)
+      Telemetry::HistogramID aId,
+      IOInterposeObserver::Operation aOp = IOInterposeObserver::OpNone)
       : start(TimeStamp::Now()),
         id(aId)
 #if defined(MOZ_GECKO_PROFILER) && !defined(XP_WIN)
@@ -102,7 +106,7 @@ class IOThreadAutoTimer {
    *
    * @param aOp IO Operation to report through the IOInterposer.
    */
-  explicit IOThreadAutoTimer()//IOInterposeObserver::Operation aOp)
+  explicit IOThreadAutoTimer(IOInterposeObserver::Operation aOp)
       : start(TimeStamp::Now()),
         id(Telemetry::HistogramCount)
 #if defined(MOZ_GECKO_PROFILER) && !defined(XP_WIN)
@@ -123,7 +127,7 @@ class IOThreadAutoTimer {
     // mechanism for intercepting I/O on that platform that captures a superset
     // of the data captured here.
 #if defined(MOZ_GECKO_PROFILER) && !defined(XP_WIN)
-    /*if (IOInterposer::IsObservedOperation(op)) {
+    if (IOInterposer::IsObservedOperation(op)) {
       const char* main_ref = "sqlite-mainthread";
       const char* other_ref = "sqlite-otherthread";
 
@@ -132,7 +136,7 @@ class IOThreadAutoTimer {
                                           (mainThread ? main_ref : other_ref));
       // Report observation
       IOInterposer::Report(ob);
-    }*/
+    }
 #endif /* defined(MOZ_GECKO_PROFILER) && !defined(XP_WIN) */
   }
 
@@ -342,7 +346,7 @@ int xClose(sqlite3_file* pFile) {
   telemetry_file* p = (telemetry_file*)pFile;
   int rc;
   {  // Scope for IOThreadAutoTimer
-    //IOThreadAutoTimer ioTimer(IOInterposeObserver::OpClose);
+    IOThreadAutoTimer ioTimer(IOInterposeObserver::OpClose);
     rc = p->pReal->pMethods->xClose(p->pReal);
   }
   if (rc == SQLITE_OK) {
@@ -378,7 +382,7 @@ int xRead(sqlite3_file* pFile, void* zBuf, int iAmt, sqlite_int64 iOfst) {
 ** Return the current file-size of a telemetry_file.
 */
 int xFileSize(sqlite3_file* pFile, sqlite_int64* pSize) {
-  //IOThreadAutoTimer ioTimer(IOInterposeObserver::OpStat);
+  IOThreadAutoTimer ioTimer(IOInterposeObserver::OpStat);
   telemetry_file* p = (telemetry_file*)pFile;
   int rc;
   rc = p->pReal->pMethods->xFileSize(p->pReal, pSize);
@@ -391,8 +395,8 @@ int xFileSize(sqlite3_file* pFile, sqlite_int64* pSize) {
 int xWrite(sqlite3_file* pFile, const void* zBuf, int iAmt,
            sqlite_int64 iOfst) {
   telemetry_file* p = (telemetry_file*)pFile;
-  /*IOThreadAutoTimer ioTimer(p->histograms->writeMS,
-                            IOInterposeObserver::OpWrite);*/
+  IOThreadAutoTimer ioTimer(p->histograms->writeMS,
+                            IOInterposeObserver::OpWrite);
   int rc;
   if (p->quotaObject) {
     MOZ_ASSERT(INT64_MAX - iOfst >= iAmt);
@@ -463,8 +467,8 @@ int xTruncate(sqlite3_file* pFile, sqlite_int64 size) {
 */
 int xSync(sqlite3_file* pFile, int flags) {
   telemetry_file* p = (telemetry_file*)pFile;
-  /*IOThreadAutoTimer ioTimer(p->histograms->syncMS,
-                            IOInterposeObserver::OpFSync);*/
+  IOThreadAutoTimer ioTimer(p->histograms->syncMS,
+                            IOInterposeObserver::OpFSync);
   return p->pReal->pMethods->xSync(p->pReal, flags);
 }
 
@@ -601,8 +605,8 @@ int xUnfetch(sqlite3_file* pFile, sqlite3_int64 iOff, void* pResOut) {
 
 int xOpen(sqlite3_vfs* vfs, const char* zName, sqlite3_file* pFile, int flags,
           int* pOutFlags) {
-  /*IOThreadAutoTimer ioTimer(Telemetry::MOZ_SQLITE_OPEN_MS,
-                            IOInterposeObserver::OpCreateOrOpen);*/
+  IOThreadAutoTimer ioTimer(Telemetry::MOZ_SQLITE_OPEN_MS,
+                            IOInterposeObserver::OpCreateOrOpen);
   Telemetry::AutoTimer<Telemetry::MOZ_SQLITE_OPEN_MS> timer;
   sqlite3_vfs* orig_vfs = static_cast<sqlite3_vfs*>(vfs->pAppData);
   int rc;
@@ -702,6 +706,43 @@ int xAccess(sqlite3_vfs* vfs, const char* zName, int flags, int* pResOut) {
 }
 
 int xFullPathname(sqlite3_vfs* vfs, const char* zName, int nOut, char* zOut) {
+#if defined(XP_WIN)
+  // SQLite uses GetFullPathnameW which also normailizes file path. If a file
+  // component ends with a dot, it would be removed. However, it's not desired.
+  //
+  // And that would result SQLite uses wrong database and quotaObject.
+  // Note that we are safe to avoid the GetFullPathnameW call for \\?\ prefixed
+  // paths.
+  // And note that this hack will be removed once the issue is fixed directly in
+  // SQLite.
+
+  // zName that starts with "//?/" is the case when a file URI was passed and
+  // zName that starts with "\\?\" is the case when a normal path was passed
+  // (not file URI).
+  if (StaticPrefs::dom_quotaManager_overrideXFullPathname() &&
+      ((zName[0] == '/' && zName[1] == '/' && zName[2] == '?' &&
+        zName[3] == '/') ||
+       (zName[0] == '\\' && zName[1] == '\\' && zName[2] == '?' &&
+        zName[3] == '\\'))) {
+    MOZ_ASSERT(nOut >= vfs->mxPathname);
+    MOZ_ASSERT(nOut > strlen(zName));
+
+    size_t index = 0;
+    while (zName[index] != '\0') {
+      if (zName[index] == '/') {
+        zOut[index] = '\\';
+      } else {
+        zOut[index] = zName[index];
+      }
+
+      index++;
+    }
+    zOut[index] = '\0';
+
+    return SQLITE_OK;
+  }
+#endif
+
   sqlite3_vfs* orig_vfs = static_cast<sqlite3_vfs*>(vfs->pAppData);
   return orig_vfs->xFullPathname(orig_vfs, zName, nOut, zOut);
 }
diff --git a/storage/build/components.conf b/storage/build/components.conf
index 705ae65f50..ef42398456 100644
--- a/storage/build/components.conf
+++ b/storage/build/components.conf
@@ -4,8 +4,10 @@
 
 Classes = [
     {
+        'js_name': 'storage',
         'cid': '{bbbb1d61-438f-4436-92ed-8308e5830fb0}',
         'contract_ids': ['@mozilla.org/storage/service;1'],
+        'interfaces': ['mozIStorageService'],
         'singleton': True,
         'type': 'mozilla::storage::Service',
         'headers': ['/storage/mozStorageService.h'],
diff --git a/storage/style.txt b/storage/style.txt
index dd6a672ad9..5391394173 100644
--- a/storage/style.txt
+++ b/storage/style.txt
@@ -56,8 +56,6 @@ BIG EXAMPLE:
 
 *** Header ***
 
-/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
- * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ : */
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
@@ -98,8 +96,6 @@ public:
 
 *** Implementation ***
 
-/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
- * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ : */
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
diff --git a/taskcluster/ci/source-test/node.yml b/taskcluster/ci/source-test/node.yml
index 5d12f70504..f056e3f04a 100644
--- a/taskcluster/ci/source-test/node.yml
+++ b/taskcluster/ci/source-test/node.yml
@@ -44,7 +44,7 @@ devtools-tests:
         command: >
             npm install &&
             cd devtools/client/bin/ &&
-            node devtools-node-test-runner.js --suite=aboutdebugging-new &&
+            node devtools-node-test-runner.js --suite=aboutdebugging &&
             node devtools-node-test-runner.js --suite=accessibility &&
             node devtools-node-test-runner.js --suite=application &&
             node devtools-node-test-runner.js --suite=framework &&
diff --git a/taskcluster/ci/test/reftest.yml b/taskcluster/ci/test/reftest.yml
index 0ef990412f..3491a0dd7c 100644
--- a/taskcluster/ci/test/reftest.yml
+++ b/taskcluster/ci/test/reftest.yml
@@ -88,13 +88,14 @@ jsreftest:
             linux64-qr/debug: 5
             linux64/debug: 5
             macosx.*-64-ccov/debug: 5
-            macosx.*-64(-shippable)?/.*: 2
+            macosx.*-64(-shippable)?/opt: 2
             default: 3
     max-run-time:
         by-test-platform:
             android-em.*: 7200
             windows10-64-ccov/debug: 7200
             macosx.*64-ccov/debug: 7200
+            linux.*64-ccov/debug: 7200
             default: 3600
     tier:
         by-test-platform:
diff --git a/third_party/rust/Inflector/.cargo-checksum.json b/third_party/rust/Inflector/.cargo-checksum.json
deleted file mode 100644
index 16741f50fd..0000000000
--- a/third_party/rust/Inflector/.cargo-checksum.json
+++ /dev/null
@@ -1 +0,0 @@
-{"files":{"Cargo.toml":"8fb633b01ea17947fd1f76e0a447b027ddf48c019671f09e39c1338ab715605d","README.md":"3c7136fc446143eecf9668e6daf7f096eb5eb3a3e312cc674571719cb4c83bcc","src/cases/camelcase/mod.rs":"8e65fca78ea88acb32c0f214cafde39b849aef253253c3681e316f2559b26977","src/cases/case/mod.rs":"16323191c983d316debd50af11f94f4c525bb70d4d1a02db06a9aed67d4ba2a9","src/cases/classcase/mod.rs":"5b6b74530a2a693bf1ac89342f1b25f58f39336b1ee3242547c3d6ef468a878f","src/cases/kebabcase/mod.rs":"b317ebd42f22daab4b23bb4b83ce85f053d7088680d3a32eecbd13bd5331587a","src/cases/mod.rs":"e272853bcc1c5f6eb02594038febb9dcebb6eca8eac744d6e503db5082e585c6","src/cases/pascalcase/mod.rs":"a44feed6d8877fd8a31160076befe826960aa001d859587aef2dddc1aedc397b","src/cases/screamingsnakecase/mod.rs":"21582eb1ec2170d379bf3536c6ffb39b8bdc096efe2d493674458ee27b86e985","src/cases/sentencecase/mod.rs":"eb21d7d5bf0b23e1325d429dfdc149081d233a8b950c1fdfe04b4bebcc2c0ddb","src/cases/snakecase/mod.rs":"369739e37e700c028022f308aa78504873c10a5e88768f05249c1c8481b30c9d","src/cases/tablecase/mod.rs":"a6a50a397059d775a517d5dce6ba612b107919e209a9eb56871a5c1d42314664","src/cases/titlecase/mod.rs":"3f0dac5e5b434da9234d6c389f67bb2d3c8f138dc521fa29dbe3791f8eaf5341","src/cases/traincase/mod.rs":"4e2493d6594d3c505de293c69390b3f672c0fd4d35603ae1a1aae48166bc18c2","src/lib.rs":"6c5cf60f5c2f8778a3ad7638f37064527b8a86f164117d867b8b6532e2cc655e","src/numbers/deordinalize/mod.rs":"a3930b0315d20d2d86747bc4ae653a0fb7f7d80de497b0aaa9873aadd1459d18","src/numbers/mod.rs":"fed4e090f8b64a34ae64ddcb68d899cfa4dd8e8422a060be01a70dbdb71b85e0","src/numbers/ordinalize/mod.rs":"ce0d88977efaa50792e7311c0e0a73a3115928f9f7be77f914824c3d80eab66c","src/string/constants/mod.rs":"38de3d5060a5d224d28d184eab8af02203c65d74c1d380720c3260ea205f3e05","src/string/deconstantize/mod.rs":"c79f2170dc41bd6abb89a6e74fbdd87bf011f62cfe1f34d8886fda0724ade6fa","src/string/demodulize/mod.rs":"bbcb5314473e4ca02feee4903e31a332caaa912ed2cbca0f49c2fe411a826215","src/string/mod.rs":"570f7ea4dd646f2d633ddd67079db922cc2cadf916719fa19c2f59b4d522ee89","src/string/pluralize/mod.rs":"5f07fab8b5f4e7af546f1e907426724714b9b27af1ecb59a91e57dccd0833a6e","src/string/singularize/mod.rs":"9c2d833cbcdc1489013642de22578d51f558a31e8d2fea4536a27f8fa1114169","src/suffix/foreignkey/mod.rs":"e7ad9a9a0a21fcb53becb36306a15eedf67958e2da18ae928ae592177e70e7a3","src/suffix/mod.rs":"f6f99ce6fc8794d5411d91533b67be5d4a2bc5994317d32f405b2fa3c5ec660d","tests/lib.rs":"e1cfcea8a146291396ff72b0a2e84c2b9ddaa0103717442c4921c165a2ab470d"},"package":"fe438c63458706e03479442743baae6c88256498e6431708f6dfc520a26515d3"}
\ No newline at end of file
diff --git a/third_party/rust/Inflector/Cargo.toml b/third_party/rust/Inflector/Cargo.toml
deleted file mode 100644
index 553f00f6de..0000000000
--- a/third_party/rust/Inflector/Cargo.toml
+++ /dev/null
@@ -1,42 +0,0 @@
-# THIS FILE IS AUTOMATICALLY GENERATED BY CARGO
-#
-# When uploading crates to the registry Cargo will automatically
-# "normalize" Cargo.toml files for maximal compatibility
-# with all versions of Cargo and also rewrite `path` dependencies
-# to registry (e.g. crates.io) dependencies
-#
-# If you believe there's an error in this file please file an
-# issue against the rust-lang/cargo repository. If you're
-# editing this file be aware that the upstream Cargo.toml
-# will likely look very different (and much more reasonable)
-
-[package]
-name = "Inflector"
-version = "0.11.4"
-authors = ["Josh Teeter<joshteeter@gmail.com>"]
-include = ["**/*.rs", "Cargo.toml", "README.md"]
-description = "Adds String based inflections for Rust. Snake, kebab, camel, sentence, class, title and table cases as well as ordinalize, deordinalize, demodulize, foreign key, and pluralize/singularize are supported as both traits and pure functions acting on String types.\n"
-homepage = "https://github.com/whatisinternet/inflector"
-documentation = "https://docs.rs/Inflector"
-readme = "README.md"
-keywords = ["pluralize", "Inflector", "camel", "snake", "inflection"]
-categories = ["text-processing", "value-formatting"]
-license = "BSD-2-Clause"
-repository = "https://github.com/whatisinternet/inflector"
-
-[lib]
-name = "inflector"
-[dependencies.lazy_static]
-version = "1.2.0"
-optional = true
-
-[dependencies.regex]
-version = "1.1"
-optional = true
-
-[features]
-default = ["heavyweight"]
-heavyweight = ["regex", "lazy_static"]
-unstable = []
-[badges.travis-ci]
-repository = "whatisinternet/Inflector"
diff --git a/third_party/rust/Inflector/README.md b/third_party/rust/Inflector/README.md
deleted file mode 100644
index db8de0992d..0000000000
--- a/third_party/rust/Inflector/README.md
+++ /dev/null
@@ -1,136 +0,0 @@
-# Rust Inflector
-
-
-[![Build Status](https://travis-ci.org/whatisinternet/Inflector.svg?branch=master)](https://travis-ci.org/whatisinternet/Inflector) [![Crates.io](https://img.shields.io/crates/v/Inflector.svg)](https://crates.io/crates/inflector)[![Crate downloads](https://img.shields.io/crates/d/Inflector.svg)](https://crates.io/crates/inflector)
-
-
-Adds String based inflections for Rust. Snake, kebab, train, camel,
-sentence, class, and title cases as well as ordinalize,
-deordinalize, demodulize, deconstantize, foreign key, table case, and pluralize/singularize are supported as both traits and pure functions
-acting on &str and String types.
-
------
-## Documentation:
-
-Documentation can be found here at the README or via rust docs below.
-
-[Rust docs with examples](https://docs.rs/Inflector)
-
------
-
-## Installation:
-
-### As a [crate](http://crates.io)
-
-```toml
-[dependencies]
-Inflector = "*"
-```
-
-### Compile yourself:
-
-1. Install [Rust and cargo](http://doc.crates.io/)
-2. git clone https://github.com/whatisinternet/Inflector
-3. Library: cd inflector && cargo build --release --lib
-4. You can find the library in target/release
-
-## Usage / Example:
-
-```rust
-...
-// to use methods like String.to_lower_case();
-extern crate inflector;
-use inflector::Inflector;
-...
-fn main() {
-...
-  let camel_case_string: String = "some_string".to_camel_case();
-...
-}
-
-```
-
-Or
-
-```rust
-...
-// to use methods like to_snake_case(&str);
-extern crate inflector;
-
-// use inflector::cases::classcase::to_class_case;
-// use inflector::cases::classcase::is_class_case;
-
-// use inflector::cases::camelcase::to_camel_case;
-// use inflector::cases::camelcase::is_camel_case;
-
-// use inflector::cases::pascalcase::to_pascal_case;
-// use inflector::cases::pascalcase::is_pascal_case;
-
-// use inflector::cases::screamingsnakecase::to_screamingsnake_case;
-// use inflector::cases::screamingsnakecase::is_screamingsnake_case;
-
-// use inflector::cases::snakecase::to_snake_case;
-// use inflector::cases::snakecase::is_snake_case;
-
-// use inflector::cases::kebabcase::to_kebab_case;
-// use inflector::cases::kebabcase::is_kebab_case;
-
-// use inflector::cases::traincase::to_train_case;
-// use inflector::cases::traincase::is_train_case;
-
-// use inflector::cases::sentencecase::to_sentence_case;
-// use inflector::cases::sentencecase::is_sentence_case;
-
-// use inflector::cases::titlecase::to_title_case;
-// use inflector::cases::titlecase::is_title_case;
-
-// use inflector::cases::tablecase::to_table_case;
-// use inflector::cases::tablecase::is_table_case;
-
-// use inflector::numbers::ordinalize::ordinalize;
-// use inflector::numbers::deordinalize::deordinalize;
-
-// use inflector::suffix::foreignkey::to_foreign_key;
-// use inflector::suffix::foreignkey::is_foreign_key;
-
-// use inflector::string::demodulize::demodulize;
-// use inflector::string::deconstantize::deconstantize;
-
-// use inflector::string::pluralize::to_plural;
-// use inflector::string::singularize::to_singular;
-...
-fn main() {
-...
-  let camel_case_string: String = to_camel_case("some_string");
-...
-}
-
-```
-
-## Advanced installation and usage:
-
-If the project doesn't require singularize, pluralize, class, table, demodulize,
-deconstantize. Then in your `cargo.toml` you may wish to specify:
-
-```toml
-[dependencies.Inflector]
-version = "*"
-default-features = false
-```
-
-Or
-
-```toml
-Inflector = {version="*", default-features=false}
-
-```
-
-To test this crate locally with features off try:
-
-```shell
-cargo test --no-default-features
-```
-
-## [Contributing](CONTRIBUTING.md)
-
-This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the [Contributor Covenant](http://contributor-covenant.org) code of conduct.
diff --git a/third_party/rust/Inflector/src/cases/camelcase/mod.rs b/third_party/rust/Inflector/src/cases/camelcase/mod.rs
deleted file mode 100644
index b09ddc65b2..0000000000
--- a/third_party/rust/Inflector/src/cases/camelcase/mod.rs
+++ /dev/null
@@ -1,370 +0,0 @@
-#![deny(warnings)]
-use cases::case::*;
-
-/// Converts a `&str` to camelCase `String`
-///
-/// ```
-///     use inflector::cases::camelcase::to_camel_case;
-///     let mock_string: &str = "fooBar";
-///     let expected_string: String = "fooBar".to_string();
-///     let asserted_string: String = to_camel_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::cases::camelcase::to_camel_case;
-///     let mock_string: &str = "FOO_BAR";
-///     let expected_string: String = "fooBar".to_string();
-///     let asserted_string: String = to_camel_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::cases::camelcase::to_camel_case;
-///     let mock_string: &str = "Foo Bar";
-///     let expected_string: String = "fooBar".to_string();
-///     let asserted_string: String = to_camel_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::cases::camelcase::to_camel_case;
-///     let mock_string: &str = "foo_bar";
-///     let expected_string: String = "fooBar".to_string();
-///     let asserted_string: String = to_camel_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::cases::camelcase::to_camel_case;
-///     let mock_string: &str = "Foo bar";
-///     let expected_string: String = "fooBar".to_string();
-///     let asserted_string: String = to_camel_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::cases::camelcase::to_camel_case;
-///     let mock_string: &str = "foo-bar";
-///     let expected_string: String = "fooBar".to_string();
-///     let asserted_string: String = to_camel_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::cases::camelcase::to_camel_case;
-///     let mock_string: &str = "FooBar";
-///     let expected_string: String = "fooBar".to_string();
-///     let asserted_string: String = to_camel_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::cases::camelcase::to_camel_case;
-///     let mock_string: &str = "FooBar3";
-///     let expected_string: String = "fooBar3".to_string();
-///     let asserted_string: String = to_camel_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::cases::camelcase::to_camel_case;
-///     let mock_string: &str = "Foo-Bar";
-///     let expected_string: String = "fooBar".to_string();
-///     let asserted_string: String = to_camel_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-pub fn to_camel_case(non_camelized_string: &str) -> String {
-    let options = CamelOptions {
-        new_word: false,
-        last_char: ' ',
-        first_word: false,
-        injectable_char: ' ',
-        has_seperator: false,
-        inverted: false,
-    };
-    to_case_camel_like(&non_camelized_string, options)
-}
-
-/// Determines if a `&str` is camelCase bool``
-///
-/// ```
-///     use inflector::cases::camelcase::is_camel_case;
-///     let mock_string: &str = "Foo";
-///     let asserted_bool: bool = is_camel_case(mock_string);
-///     assert!(asserted_bool == false);
-///
-///
-/// ```
-/// ```
-///     use inflector::cases::camelcase::is_camel_case;
-///     let mock_string: &str = "foo";
-///     let asserted_bool: bool = is_camel_case(mock_string);
-///     assert!(asserted_bool == true);
-///
-///
-/// ```
-/// ```
-///     use inflector::cases::camelcase::is_camel_case;
-///     let mock_string: &str = "foo-bar-string-that-is-really-really-long";
-///     let asserted_bool: bool = is_camel_case(mock_string);
-///     assert!(asserted_bool == false);
-///
-///
-/// ```
-/// ```
-///     use inflector::cases::camelcase::is_camel_case;
-///     let mock_string: &str = "FooBarIsAReallyReallyLongString";
-///     let asserted_bool: bool = is_camel_case(mock_string);
-///     assert!(asserted_bool == false);
-///
-///
-/// ```
-/// ```
-///     use inflector::cases::camelcase::is_camel_case;
-///     let mock_string: &str = "fooBarIsAReallyReally3LongString";
-///     let asserted_bool: bool = is_camel_case(mock_string);
-///     assert!(asserted_bool == true);
-///
-///
-/// ```
-/// ```
-///     use inflector::cases::camelcase::is_camel_case;
-///     let mock_string: &str = "fooBarIsAReallyReallyLongString";
-///     let asserted_bool: bool = is_camel_case(mock_string);
-///     assert!(asserted_bool == true);
-///
-///
-/// ```
-/// ```
-///     use inflector::cases::camelcase::is_camel_case;
-///     let mock_string: &str = "FOO_BAR_STRING_THAT_IS_REALLY_REALLY_LONG";
-///     let asserted_bool: bool = is_camel_case(mock_string);
-///     assert!(asserted_bool == false);
-///
-///
-/// ```
-/// ```
-///     use inflector::cases::camelcase::is_camel_case;
-///     let mock_string: &str = "foo_bar_string_that_is_really_really_long";
-///     let asserted_bool: bool = is_camel_case(mock_string);
-///     assert!(asserted_bool == false);
-///
-///
-/// ```
-/// ```
-///     use inflector::cases::camelcase::is_camel_case;
-///     let mock_string: &str = "Foo bar string that is really really long";
-///     let asserted_bool: bool = is_camel_case(mock_string);
-///     assert!(asserted_bool == false);
-///
-///
-/// ```
-/// ```
-///     use inflector::cases::camelcase::is_camel_case;
-///     let mock_string: &str = "Foo Bar Is A Really Really Long String";
-///     let asserted_bool: bool = is_camel_case(mock_string);
-///     assert!(asserted_bool == false);
-/// ```
-pub fn is_camel_case(test_string: &str) -> bool {
-    to_camel_case(&test_string.clone()) == test_string
-}
-
-#[cfg(all(feature = "unstable", test))]
-mod benchmarks {
-    extern crate test;
-    use self::test::Bencher;
-
-    #[bench]
-    fn bench_camel0(b: &mut Bencher) {
-        b.iter(|| {
-            let test_string = "Foo bar";
-            super::to_camel_case(test_string)
-        });
-    }
-
-    #[bench]
-    fn bench_camel1(b: &mut Bencher) {
-        b.iter(|| {
-            let test_string = "foo_bar";
-            super::to_camel_case(test_string)
-        });
-    }
-
-    #[bench]
-    fn bench_camel2(b: &mut Bencher) {
-        b.iter(|| {
-            let test_string = "fooBar";
-            super::to_camel_case(test_string)
-        });
-    }
-
-    #[bench]
-    fn bench_is_camel(b: &mut Bencher) {
-        b.iter(|| {
-            let test_string: &str = "Foo bar";
-            super::is_camel_case(test_string)
-        });
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use ::to_camel_case;
-    use ::is_camel_case;
-
-    #[test]
-    fn from_camel_case() {
-        let convertable_string: String = "fooBar".to_owned();
-        let expected: String = "fooBar".to_owned();
-        assert_eq!(to_camel_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_pascal_case() {
-        let convertable_string: String = "FooBar".to_owned();
-        let expected: String = "fooBar".to_owned();
-        assert_eq!(to_camel_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_kebab_case() {
-        let convertable_string: String = "foo-bar".to_owned();
-        let expected: String = "fooBar".to_owned();
-        assert_eq!(to_camel_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_sentence_case() {
-        let convertable_string: String = "Foo bar".to_owned();
-        let expected: String = "fooBar".to_owned();
-        assert_eq!(to_camel_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_title_case() {
-        let convertable_string: String = "Foo Bar".to_owned();
-        let expected: String = "fooBar".to_owned();
-        assert_eq!(to_camel_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_train_case() {
-        let convertable_string: String = "Foo-Bar".to_owned();
-        let expected: String = "fooBar".to_owned();
-        assert_eq!(to_camel_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_screaming_snake_case() {
-        let convertable_string: String = "FOO_BAR".to_owned();
-        let expected: String = "fooBar".to_owned();
-        assert_eq!(to_camel_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_snake_case() {
-        let convertable_string: String = "foo_bar".to_owned();
-        let expected: String = "fooBar".to_owned();
-        assert_eq!(to_camel_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_case_with_loads_of_space() {
-        let convertable_string: String = "foo           bar".to_owned();
-        let expected: String = "fooBar".to_owned();
-        assert_eq!(to_camel_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn a_name_with_a_dot() {
-        let convertable_string: String = "Robert C. Martin".to_owned();
-        let expected: String = "robertCMartin".to_owned();
-        assert_eq!(to_camel_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn random_text_with_bad_chars() {
-        let convertable_string: String = "Random text with *(bad) chars".to_owned();
-        let expected: String = "randomTextWithBadChars".to_owned();
-        assert_eq!(to_camel_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn trailing_bad_chars() {
-        let convertable_string: String = "trailing bad_chars*(()())".to_owned();
-        let expected: String = "trailingBadChars".to_owned();
-        assert_eq!(to_camel_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn leading_bad_chars() {
-        let convertable_string: String = "-!#$%leading bad chars".to_owned();
-        let expected: String = "leadingBadChars".to_owned();
-        assert_eq!(to_camel_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn wrapped_in_bad_chars() {
-        let convertable_string: String = "-!#$%wrapped in bad chars&*^*&(&*^&(<><?>><?><>))".to_owned();
-        let expected: String = "wrappedInBadChars".to_owned();
-        assert_eq!(to_camel_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn has_a_sign() {
-        let convertable_string: String = "has a + sign".to_owned();
-        let expected: String = "hasASign".to_owned();
-        assert_eq!(to_camel_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn is_correct_from_camel_case() {
-        let convertable_string: String = "fooBar".to_owned();
-        assert_eq!(is_camel_case(&convertable_string), true)
-    }
-
-    #[test]
-    fn is_correct_from_pascal_case() {
-        let convertable_string: String = "FooBar".to_owned();
-        assert_eq!(is_camel_case(&convertable_string), false)
-    }
-
-    #[test]
-    fn is_correct_from_kebab_case() {
-        let convertable_string: String = "foo-bar".to_owned();
-        assert_eq!(is_camel_case(&convertable_string), false)
-    }
-
-    #[test]
-    fn is_correct_from_sentence_case() {
-        let convertable_string: String = "Foo bar".to_owned();
-        assert_eq!(is_camel_case(&convertable_string), false)
-    }
-
-    #[test]
-    fn is_correct_from_title_case() {
-        let convertable_string: String = "Foo Bar".to_owned();
-        assert_eq!(is_camel_case(&convertable_string), false)
-    }
-
-    #[test]
-    fn is_correct_from_train_case() {
-        let convertable_string: String = "Foo-Bar".to_owned();
-        assert_eq!(is_camel_case(&convertable_string), false)
-    }
-
-    #[test]
-    fn is_correct_from_screaming_snake_case() {
-        let convertable_string: String = "FOO_BAR".to_owned();
-        assert_eq!(is_camel_case(&convertable_string), false)
-    }
-
-    #[test]
-    fn is_correct_from_snake_case() {
-        let convertable_string: String = "foo_bar".to_owned();
-        assert_eq!(is_camel_case(&convertable_string), false)
-    }
-}
-
diff --git a/third_party/rust/Inflector/src/cases/case/mod.rs b/third_party/rust/Inflector/src/cases/case/mod.rs
deleted file mode 100644
index bb4c3d2e33..0000000000
--- a/third_party/rust/Inflector/src/cases/case/mod.rs
+++ /dev/null
@@ -1,303 +0,0 @@
-#![deny(warnings)]
-#[allow(unknown_lints)]
-#[allow(unused_imports)]
-use std::ascii::*;
-
-pub struct CamelOptions {
-    pub new_word: bool,
-    pub last_char: char,
-    pub first_word: bool,
-    pub injectable_char: char,
-    pub has_seperator: bool,
-    pub inverted: bool,
-}
-
-pub fn to_case_snake_like(convertable_string: &str, replace_with: &str, case: &str) -> String {
-    let mut first_character: bool = true;
-    let mut result: String = String::with_capacity(convertable_string.len() * 2);
-    for char_with_index in trim_right(convertable_string).char_indices() {
-        if char_is_seperator(&char_with_index.1) {
-            if !first_character {
-                first_character = true;
-                result.push(replace_with.chars().nth(0).unwrap_or('_'));
-            }
-        } else if requires_seperator(char_with_index, first_character, &convertable_string) {
-            first_character = false;
-            result = snake_like_with_seperator(result, replace_with, &char_with_index.1, case)
-        } else {
-            first_character = false;
-            result = snake_like_no_seperator(result, &char_with_index.1, case)
-        }
-    }
-    result
-}
-
-pub fn to_case_camel_like(convertable_string: &str, camel_options: CamelOptions) -> String {
-    let mut new_word: bool = camel_options.new_word;
-    let mut first_word: bool = camel_options.first_word;
-    let mut last_char: char = camel_options.last_char;
-    let mut found_real_char: bool = false;
-    let mut result: String = String::with_capacity(convertable_string.len() * 2);
-    for character in trim_right(convertable_string).chars() {
-        if char_is_seperator(&character) && found_real_char {
-            new_word = true;
-        } else if !found_real_char && is_not_alphanumeric(character) {
-            continue;
-        } else if character.is_numeric() {
-            found_real_char = true;
-            new_word = true;
-            result.push(character);
-        } else if last_char_lower_current_is_upper_or_new_word(new_word, last_char, character) {
-            found_real_char = true;
-            new_word = false;
-            result = append_on_new_word(result, first_word, character, &camel_options);
-            first_word = false;
-        } else {
-            found_real_char = true;
-            last_char = character;
-            result.push(character.to_ascii_lowercase());
-        }
-    }
-    result
-}
-
-#[inline]
-fn append_on_new_word(mut result: String, first_word: bool, character: char, camel_options: &CamelOptions) -> String {
-    if not_first_word_and_has_seperator(first_word, camel_options.has_seperator) {
-        result.push(camel_options.injectable_char);
-    }
-    if first_word_or_not_inverted(first_word, camel_options.inverted) {
-        result.push(character.to_ascii_uppercase());
-    } else {
-        result.push(character.to_ascii_lowercase());
-    }
-    result
-}
-
-fn not_first_word_and_has_seperator(first_word: bool, has_seperator: bool) -> bool {
-    has_seperator && !first_word
-}
-
-fn first_word_or_not_inverted(first_word: bool, inverted: bool) -> bool {
-    !inverted || first_word
-}
-
-
-fn last_char_lower_current_is_upper_or_new_word(new_word: bool, last_char: char, character: char) -> bool{
-    new_word ||
-        ((last_char.is_lowercase() && character.is_uppercase()) &&
-         (last_char != ' '))
-}
-
-fn char_is_seperator(character: &char) -> bool {
-    is_not_alphanumeric(*character)
-}
-
-fn trim_right(convertable_string: &str) -> &str {
-    convertable_string.trim_end_matches(is_not_alphanumeric)
-}
-
-fn is_not_alphanumeric(character: char) -> bool {
-    !character.is_alphanumeric()
-}
-
-#[inline]
-fn requires_seperator(char_with_index: (usize, char), first_character: bool, convertable_string: &str) -> bool {
-    !first_character &&
-        char_is_uppercase(char_with_index.1) &&
-            next_or_previous_char_is_lowercase(convertable_string, char_with_index.0)
-}
-
-#[inline]
-fn snake_like_no_seperator(mut accumlator: String, current_char: &char, case: &str) -> String {
-    if case == "lower" {
-        accumlator.push(current_char.to_ascii_lowercase());
-        accumlator
-    } else {
-        accumlator.push(current_char.to_ascii_uppercase());
-        accumlator
-    }
-}
-
-#[inline]
-fn snake_like_with_seperator(mut accumlator: String, replace_with: &str, current_char: &char, case: &str) -> String {
-    if case == "lower" {
-        accumlator.push(replace_with.chars().nth(0).unwrap_or('_'));
-        accumlator.push(current_char.to_ascii_lowercase());
-        accumlator
-    } else {
-        accumlator.push(replace_with.chars().nth(0).unwrap_or('_'));
-        accumlator.push(current_char.to_ascii_uppercase());
-        accumlator
-    }
-}
-
-fn next_or_previous_char_is_lowercase(convertable_string: &str, char_with_index: usize) -> bool {
-    convertable_string.chars().nth(char_with_index + 1).unwrap_or('A').is_lowercase() ||
-        convertable_string.chars().nth(char_with_index - 1).unwrap_or('A').is_lowercase()
-}
-
-fn char_is_uppercase(test_char: char) -> bool {
-    test_char == test_char.to_ascii_uppercase()
-}
-
-#[test]
-fn test_trim_bad_chars() {
-    assert_eq!("abc", trim_right("abc----^"))
-}
-
-#[test]
-fn test_trim_bad_chars_when_none_are_bad() {
-    assert_eq!("abc", trim_right("abc"))
-}
-
-#[test]
-fn test_is_not_alphanumeric_on_is_alphanumeric() {
-    assert!(!is_not_alphanumeric('a'))
-}
-
-#[test]
-fn test_is_not_alphanumeric_on_is_not_alphanumeric() {
-    assert!(is_not_alphanumeric('_'))
-}
-
-
-#[test]
-fn test_char_is_uppercase_when_it_is() {
-    assert_eq!(char_is_uppercase('A'), true)
-}
-
-#[test]
-fn test_char_is_uppercase_when_it_is_not() {
-    assert_eq!(char_is_uppercase('a'), false)
-}
-
-#[test]
-fn test_next_or_previous_char_is_lowercase_true() {
-    assert_eq!(next_or_previous_char_is_lowercase("TestWWW", 3), true)
-}
-
-#[test]
-fn test_next_or_previous_char_is_lowercase_false() {
-    assert_eq!(next_or_previous_char_is_lowercase("TestWWW", 5), false)
-}
-
-#[test]
-fn snake_like_with_seperator_lowers() {
-    assert_eq!(snake_like_with_seperator("".to_owned(), "^", &'c', "lower"), "^c".to_string())
-}
-
-#[test]
-fn snake_like_with_seperator_upper() {
-    assert_eq!(snake_like_with_seperator("".to_owned(), "^", &'c', "upper"), "^C".to_string())
-}
-
-#[test]
-fn snake_like_no_seperator_lower() {
-    assert_eq!(snake_like_no_seperator("".to_owned(), &'C', "lower"), "c".to_string())
-}
-
-#[test]
-fn snake_like_no_seperator_upper() {
-    assert_eq!(snake_like_no_seperator("".to_owned(), &'c', "upper"), "C".to_string())
-}
-
-#[test]
-fn requires_seperator_upper_not_first_wrap_is_safe_current_upper() {
-    assert_eq!(requires_seperator((2, 'C'), false, "test"), true)
-}
-
-#[test]
-fn requires_seperator_upper_not_first_wrap_is_safe_current_lower() {
-    assert_eq!(requires_seperator((2, 'c'), false, "test"), false)
-}
-
-#[test]
-fn requires_seperator_upper_first_wrap_is_safe_current_upper() {
-    assert_eq!(requires_seperator((0, 'T'), true, "Test"), false)
-}
-
-#[test]
-fn requires_seperator_upper_first_wrap_is_safe_current_lower() {
-    assert_eq!(requires_seperator((0, 't'), true, "Test"), false)
-}
-
-#[test]
-fn requires_seperator_upper_first_wrap_is_safe_current_lower_next_is_too() {
-    assert_eq!(requires_seperator((0, 't'), true, "test"), false)
-}
-
-#[test]
-fn test_char_is_seperator_dash() {
-    assert_eq!(char_is_seperator(&'-'), true)
-}
-
-#[test]
-fn test_char_is_seperator_underscore() {
-    assert_eq!(char_is_seperator(&'_'), true)
-}
-
-#[test]
-fn test_char_is_seperator_space() {
-    assert_eq!(char_is_seperator(&' '), true)
-}
-
-#[test]
-fn test_char_is_seperator_when_not() {
-    assert_eq!(char_is_seperator(&'A'), false)
-}
-
-#[test]
-fn test_last_char_lower_current_is_upper_or_new_word_with_new_word() {
-    assert_eq!(last_char_lower_current_is_upper_or_new_word(true, ' ', '-'), true)
-}
-
-#[test]
-fn test_last_char_lower_current_is_upper_or_new_word_last_char_space() {
-    assert_eq!(last_char_lower_current_is_upper_or_new_word(false, ' ', '-'), false)
-}
-
-#[test]
-fn test_last_char_lower_current_is_upper_or_new_word_last_char_lower_current_upper() {
-    assert_eq!(last_char_lower_current_is_upper_or_new_word(false, 'a', 'A'), true)
-}
-
-#[test]
-fn test_last_char_lower_current_is_upper_or_new_word_last_char_upper_current_upper() {
-    assert_eq!(last_char_lower_current_is_upper_or_new_word(false, 'A', 'A'), false)
-}
-
-#[test]
-fn test_last_char_lower_current_is_upper_or_new_word_last_char_upper_current_lower() {
-    assert_eq!(last_char_lower_current_is_upper_or_new_word(false, 'A', 'a'), false)
-}
-
-#[test]
-fn test_first_word_or_not_inverted_with_first_word() {
-    assert_eq!(first_word_or_not_inverted(true, false), true)
-}
-
-#[test]
-fn test_first_word_or_not_inverted_not_first_word_not_inverted() {
-    assert_eq!(first_word_or_not_inverted(false, false), true)
-}
-
-#[test]
-fn test_first_word_or_not_inverted_not_first_word_is_inverted() {
-    assert_eq!(first_word_or_not_inverted(false, true), false)
-}
-
-#[test]
-fn test_not_first_word_and_has_seperator_is_first_and_not_seperator() {
-    assert_eq!(not_first_word_and_has_seperator(true, false), false)
-}
-
-#[test]
-fn test_not_first_word_and_has_seperator_not_first_and_not_seperator() {
-    assert_eq!(not_first_word_and_has_seperator(false, false), false)
-}
-
-#[test]
-fn test_not_first_word_and_has_seperator_not_first_and_has_seperator() {
-    assert_eq!(not_first_word_and_has_seperator(false, true), true)
-}
diff --git a/third_party/rust/Inflector/src/cases/classcase/mod.rs b/third_party/rust/Inflector/src/cases/classcase/mod.rs
deleted file mode 100644
index e0b6ef6f48..0000000000
--- a/third_party/rust/Inflector/src/cases/classcase/mod.rs
+++ /dev/null
@@ -1,393 +0,0 @@
-#![deny(warnings)]
-use cases::case::*;
-#[cfg(feature = "heavyweight")]
-use string::singularize::to_singular;
-#[cfg(feature = "heavyweight")]
-/// Converts a `&str` to `ClassCase` `String`
-///
-/// ```
-///     use inflector::cases::classcase::to_class_case;
-///     let mock_string: &str = "FooBar";
-///     let expected_string: String = "FooBar".to_string();
-///     let asserted_string: String = to_class_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-///
-/// ```
-///     use inflector::cases::classcase::to_class_case;
-///     let mock_string: &str = "FooBars";
-///     let expected_string: String = "FooBar".to_string();
-///     let asserted_string: String = to_class_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-///
-/// ```
-///     use inflector::cases::classcase::to_class_case;
-///     let mock_string: &str = "Foo Bar";
-///     let expected_string: String = "FooBar".to_string();
-///     let asserted_string: String = to_class_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-///
-/// ```
-///     use inflector::cases::classcase::to_class_case;
-///     let mock_string: &str = "foo-bar";
-///     let expected_string: String = "FooBar".to_string();
-///     let asserted_string: String = to_class_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-///
-/// ```
-///     use inflector::cases::classcase::to_class_case;
-///     let mock_string: &str = "fooBar";
-///     let expected_string: String = "FooBar".to_string();
-///     let asserted_string: String = to_class_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-///
-/// ```
-///     use inflector::cases::classcase::to_class_case;
-///     let mock_string: &str = "FOO_BAR";
-///     let expected_string: String = "FooBar".to_string();
-///     let asserted_string: String = to_class_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-///
-/// ```
-///     use inflector::cases::classcase::to_class_case;
-///     let mock_string: &str = "foo_bar";
-///     let expected_string: String = "FooBar".to_string();
-///     let asserted_string: String = to_class_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-///
-/// ```
-///     use inflector::cases::classcase::to_class_case;
-///     let mock_string: &str = "foo_bars";
-///     let expected_string: String = "FooBar".to_string();
-///     let asserted_string: String = to_class_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-///
-/// ```
-///     use inflector::cases::classcase::to_class_case;
-///     let mock_string: &str = "Foo bar";
-///     let expected_string: String = "FooBar".to_string();
-///     let asserted_string: String = to_class_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-pub fn to_class_case(non_class_case_string: &str) -> String {
-    let options = CamelOptions {
-        new_word: true,
-        last_char: ' ',
-        first_word: false,
-        injectable_char: ' ',
-        has_seperator: false,
-        inverted: false,
-    };
-    let class_plural = to_case_camel_like(non_class_case_string, options);
-    let split: (&str, &str) =
-        class_plural.split_at(class_plural.rfind(char::is_uppercase).unwrap_or(0));
-    format!("{}{}", split.0, to_singular(split.1))
-}
-
-#[cfg(feature = "heavyweight")]
-/// Determines if a `&str` is `ClassCase` `bool`
-///
-/// ```
-///     use inflector::cases::classcase::is_class_case;
-///     let mock_string: &str = "Foo";
-///     let asserted_bool: bool = is_class_case(mock_string);
-///     assert!(asserted_bool == true);
-///
-/// ```
-///
-/// ```
-///     use inflector::cases::classcase::is_class_case;
-///     let mock_string: &str = "foo";
-///     let asserted_bool: bool = is_class_case(mock_string);
-///     assert!(asserted_bool == false);
-///
-/// ```
-///
-/// ```
-///     use inflector::cases::classcase::is_class_case;
-///     let mock_string: &str = "FooBarIsAReallyReallyLongStrings";
-///     let asserted_bool: bool = is_class_case(mock_string);
-///     assert!(asserted_bool == false);
-///
-/// ```
-///
-///
-/// ```
-///     use inflector::cases::classcase::is_class_case;
-///     let mock_string: &str = "FooBarIsAReallyReallyLongString";
-///     let asserted_bool: bool = is_class_case(mock_string);
-///     assert!(asserted_bool == true);
-///
-/// ```
-///
-/// ```
-///     use inflector::cases::classcase::is_class_case;
-///     let mock_string: &str = "foo-bar-string-that-is-really-really-long";
-///     let asserted_bool: bool = is_class_case(mock_string);
-///     assert!(asserted_bool == false);
-///
-/// ```
-///
-/// ```
-///     use inflector::cases::classcase::is_class_case;
-///     let mock_string: &str = "foo_bar_is_a_really_really_long_strings";
-///     let asserted_bool: bool = is_class_case(mock_string);
-///     assert!(asserted_bool == false);
-///
-/// ```
-///
-///
-/// ```
-///     use inflector::cases::classcase::is_class_case;
-///     let mock_string: &str = "fooBarIsAReallyReallyLongString";
-///     let asserted_bool: bool = is_class_case(mock_string);
-///     assert!(asserted_bool == false);
-///
-/// ```
-///
-/// ```
-///     use inflector::cases::classcase::is_class_case;
-///     let mock_string: &str = "FOO_BAR_STRING_THAT_IS_REALLY_REALLY_LONG";
-///     let asserted_bool: bool = is_class_case(mock_string);
-///     assert!(asserted_bool == false);
-///
-/// ```
-///
-/// ```
-///     use inflector::cases::classcase::is_class_case;
-///     let mock_string: &str = "foo_bar_string_that_is_really_really_long";
-///     let asserted_bool: bool = is_class_case(mock_string);
-///     assert!(asserted_bool == false);
-///
-/// ```
-///
-/// ```
-///     use inflector::cases::classcase::is_class_case;
-///     let mock_string: &str = "Foo bar string that is really really long";
-///     let asserted_bool: bool = is_class_case(mock_string);
-///     assert!(asserted_bool == false);
-///
-/// ```
-///
-/// ```
-///     use inflector::cases::classcase::is_class_case;
-///     let mock_string: &str = "Foo Bar Is A Really Really Long String";
-///     let asserted_bool: bool = is_class_case(mock_string);
-///     assert!(asserted_bool == false);
-///
-/// ```
-pub fn is_class_case(test_string: &str) -> bool {
-    to_class_case(&test_string.clone()) == test_string
-}
-
-#[cfg(all(feature = "unstable", test))]
-#[cfg(feature = "heavyweight")]
-mod benchmarks {
-    extern crate test;
-    use self::test::Bencher;
-
-    #[bench]
-    fn bench_class_case(b: &mut Bencher) {
-        b.iter(|| super::to_class_case("Foo bar"));
-    }
-
-    #[bench]
-    fn bench_is_class(b: &mut Bencher) {
-        b.iter(|| super::is_class_case("Foo bar"));
-    }
-
-    #[bench]
-    fn bench_class_from_snake(b: &mut Bencher) {
-        b.iter(|| super::to_class_case("foo_bar"));
-    }
-}
-
-#[cfg(test)]
-#[cfg(feature = "heavyweight")]
-mod tests {
-    use ::to_class_case;
-    use ::is_class_case;
-
-    #[test]
-    fn from_camel_case() {
-        let convertable_string: String = "fooBar".to_owned();
-        let expected: String = "FooBar".to_owned();
-        assert_eq!(to_class_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_pascal_case() {
-        let convertable_string: String = "FooBar".to_owned();
-        let expected: String = "FooBar".to_owned();
-        assert_eq!(to_class_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_kebab_case() {
-        let convertable_string: String = "foo-bar".to_owned();
-        let expected: String = "FooBar".to_owned();
-        assert_eq!(to_class_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_sentence_case() {
-        let convertable_string: String = "Foo bar".to_owned();
-        let expected: String = "FooBar".to_owned();
-        assert_eq!(to_class_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_title_case() {
-        let convertable_string: String = "Foo Bar".to_owned();
-        let expected: String = "FooBar".to_owned();
-        assert_eq!(to_class_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_train_case() {
-        let convertable_string: String = "Foo-Bar".to_owned();
-        let expected: String = "FooBar".to_owned();
-        assert_eq!(to_class_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_screaming_class_case() {
-        let convertable_string: String = "FOO_BAR".to_owned();
-        let expected: String = "FooBar".to_owned();
-        assert_eq!(to_class_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_snake_case() {
-        let convertable_string: String = "foo_bar".to_owned();
-        let expected: String = "FooBar".to_owned();
-        assert_eq!(to_class_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_table_case() {
-        let convertable_string: String = "foo_bars".to_owned();
-        let expected: String = "FooBar".to_owned();
-        assert_eq!(to_class_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_case_with_loads_of_space() {
-        let convertable_string: String = "foo           bar".to_owned();
-        let expected: String = "FooBar".to_owned();
-        assert_eq!(to_class_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn a_name_with_a_dot() {
-        let convertable_string: String = "Robert C. Martin".to_owned();
-        let expected: String = "RobertCMartin".to_owned();
-        assert_eq!(to_class_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn random_text_with_bad_chars() {
-        let convertable_string: String = "Random text with *(bad) chars".to_owned();
-        let expected: String = "RandomTextWithBadChar".to_owned();
-        assert_eq!(to_class_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn trailing_bad_chars() {
-        let convertable_string: String = "trailing bad_chars*(()())".to_owned();
-        let expected: String = "TrailingBadChar".to_owned();
-        assert_eq!(to_class_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn leading_bad_chars() {
-        let convertable_string: String = "-!#$%leading bad chars".to_owned();
-        let expected: String = "LeadingBadChar".to_owned();
-        assert_eq!(to_class_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn wrapped_in_bad_chars() {
-        let convertable_string: String = "-!#$%wrapped in bad chars&*^*&(&*^&(<><?>><?><>))".to_owned();
-        let expected: String = "WrappedInBadChar".to_owned();
-        assert_eq!(to_class_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn has_a_sign() {
-        let convertable_string: String = "has a + sign".to_owned();
-        let expected: String = "HasASign".to_owned();
-        assert_eq!(to_class_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn is_correct_from_class_case() {
-        let convertable_string: String = "fooBar".to_owned();
-        assert_eq!(is_class_case(&convertable_string), false)
-    }
-
-    #[test]
-    fn is_correct_from_pascal_case() {
-        let convertable_string: String = "FooBar".to_owned();
-        assert_eq!(is_class_case(&convertable_string), true)
-    }
-
-    #[test]
-    fn is_correct_from_kebab_case() {
-        let convertable_string: String = "foo-bar".to_owned();
-        assert_eq!(is_class_case(&convertable_string), false)
-    }
-
-    #[test]
-    fn is_correct_from_sentence_case() {
-        let convertable_string: String = "Foo bar".to_owned();
-        assert_eq!(is_class_case(&convertable_string), false)
-    }
-
-    #[test]
-    fn is_correct_from_title_case() {
-        let convertable_string: String = "Foo Bar".to_owned();
-        assert_eq!(is_class_case(&convertable_string), false)
-    }
-
-    #[test]
-    fn is_correct_from_train_case() {
-        let convertable_string: String = "Foo-Bar".to_owned();
-        assert_eq!(is_class_case(&convertable_string), false)
-    }
-
-    #[test]
-    fn is_correct_from_screaming_snake_case() {
-        let convertable_string: String = "FOO_BAR".to_owned();
-        assert_eq!(is_class_case(&convertable_string), false)
-    }
-
-    #[test]
-    fn is_correct_from_snake_case() {
-        let convertable_string: String = "foo_bar".to_owned();
-        assert_eq!(is_class_case(&convertable_string), false)
-    }
-
-    #[test]
-    fn is_correct_from_table_case() {
-        let convertable_string: String = "FooBar".to_owned();
-        assert_eq!(is_class_case(&convertable_string), true)
-    }
-}
-
diff --git a/third_party/rust/Inflector/src/cases/kebabcase/mod.rs b/third_party/rust/Inflector/src/cases/kebabcase/mod.rs
deleted file mode 100644
index d79f27362a..0000000000
--- a/third_party/rust/Inflector/src/cases/kebabcase/mod.rs
+++ /dev/null
@@ -1,262 +0,0 @@
-#![deny(warnings)]
-use cases::case::*;
-/// Determines if a `&str` is `kebab-case`
-///
-/// ```
-///     use inflector::cases::kebabcase::is_kebab_case;
-///     let mock_string: &str = "foo-bar-string-that-is-really-really-long";
-///     let asserted_bool: bool = is_kebab_case(mock_string);
-///     assert!(asserted_bool == true);
-///
-/// ```
-///
-/// ```
-///     use inflector::cases::kebabcase::is_kebab_case;
-///     let mock_string: &str = "FooBarIsAReallyReallyLongString";
-///     let asserted_bool: bool = is_kebab_case(mock_string);
-///     assert!(asserted_bool == false);
-///
-/// ```
-///
-/// ```
-///     use inflector::cases::kebabcase::is_kebab_case;
-///     let mock_string: &str = "fooBarIsAReallyReallyLongString";
-///     let asserted_bool: bool = is_kebab_case(mock_string);
-///     assert!(asserted_bool == false);
-///
-/// ```
-///
-/// ```
-///     use inflector::cases::kebabcase::is_kebab_case;
-///     let mock_string: &str = "FOO_BAR_STRING_THAT_IS_REALLY_REALLY_LONG";
-///     let asserted_bool: bool = is_kebab_case(mock_string);
-///     assert!(asserted_bool == false);
-///
-/// ```
-///
-/// ```
-///     use inflector::cases::kebabcase::is_kebab_case;
-///     let mock_string: &str = "foo_bar_string_that_is_really_really_long";
-///     let asserted_bool: bool = is_kebab_case(mock_string);
-///     assert!(asserted_bool == false);
-///
-/// ```
-///
-/// ```
-///     use inflector::cases::kebabcase::is_kebab_case;
-///     let mock_string: &str = "Foo bar string that is really really long";
-///     let asserted_bool: bool = is_kebab_case(mock_string);
-///     assert!(asserted_bool == false);
-///
-/// ```
-///
-/// ```
-///     use inflector::cases::kebabcase::is_kebab_case;
-///     let mock_string: &str = "Foo Bar Is A Really Really Long String";
-///     let asserted_bool: bool = is_kebab_case(mock_string);
-///     assert!(asserted_bool == false);
-///
-/// ```
-pub fn is_kebab_case(test_string: &str) -> bool {
-    test_string == to_kebab_case(test_string.clone())
-}
-
-/// Converts a `&str` to `kebab-case` `String`
-///
-/// ```
-///     use inflector::cases::kebabcase::to_kebab_case;
-///     let mock_string: &str = "foo-bar";
-///     let expected_string: String = "foo-bar".to_string();
-///     let asserted_string: String = to_kebab_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-///
-/// ```
-///     use inflector::cases::kebabcase::to_kebab_case;
-///     let mock_string: &str = "FOO_BAR";
-///     let expected_string: String = "foo-bar".to_string();
-///     let asserted_string: String = to_kebab_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-///
-/// ```
-///     use inflector::cases::kebabcase::to_kebab_case;
-///     let mock_string: &str = "foo_bar";
-///     let expected_string: String = "foo-bar".to_string();
-///     let asserted_string: String = to_kebab_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-///
-/// ```
-///     use inflector::cases::kebabcase::to_kebab_case;
-///     let mock_string: &str = "Foo Bar";
-///     let expected_string: String = "foo-bar".to_string();
-///     let asserted_string: String = to_kebab_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-///
-/// ```
-///     use inflector::cases::kebabcase::to_kebab_case;
-///     let mock_string: &str = "Foo bar";
-///     let expected_string: String = "foo-bar".to_string();
-///     let asserted_string: String = to_kebab_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-///
-/// ```
-///     use inflector::cases::kebabcase::to_kebab_case;
-///     let mock_string: &str = "FooBar";
-///     let expected_string: String = "foo-bar".to_string();
-///     let asserted_string: String = to_kebab_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-///
-/// ```
-///     use inflector::cases::kebabcase::to_kebab_case;
-///     let mock_string: &str = "fooBar";
-///     let expected_string: String = "foo-bar".to_string();
-///     let asserted_string: String = to_kebab_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-pub fn to_kebab_case(non_kebab_case_string: &str) -> String {
-    to_case_snake_like(non_kebab_case_string, "-", "lower")
-}
-
-#[cfg(all(feature = "unstable", test))]
-mod benchmarks {
-    extern crate test;
-    use self::test::Bencher;
-
-    #[bench]
-    fn bench_kebab(b: &mut Bencher) {
-        b.iter(|| super::to_kebab_case("Foo bar"));
-    }
-
-    #[bench]
-    fn bench_is_kebab(b: &mut Bencher) {
-        b.iter(|| super::is_kebab_case("Foo bar"));
-    }
-
-    #[bench]
-    fn bench_kebab_from_snake(b: &mut Bencher) {
-        b.iter(|| super::to_kebab_case("test_test_test"));
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use ::to_kebab_case;
-    use ::is_kebab_case;
-
-    #[test]
-    fn from_camel_case() {
-        let convertable_string: String = "fooBar".to_owned();
-        let expected: String = "foo-bar".to_owned();
-        assert_eq!(to_kebab_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_pascal_case() {
-        let convertable_string: String = "FooBar".to_owned();
-        let expected: String = "foo-bar".to_owned();
-        assert_eq!(to_kebab_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_kebab_case() {
-        let convertable_string: String = "foo-bar".to_owned();
-        let expected: String = "foo-bar".to_owned();
-        assert_eq!(to_kebab_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_sentence_case() {
-        let convertable_string: String = "Foo bar".to_owned();
-        let expected: String = "foo-bar".to_owned();
-        assert_eq!(to_kebab_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_title_case() {
-        let convertable_string: String = "Foo Bar".to_owned();
-        let expected: String = "foo-bar".to_owned();
-        assert_eq!(to_kebab_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_train_case() {
-        let convertable_string: String = "Foo-Bar".to_owned();
-        let expected: String = "foo-bar".to_owned();
-        assert_eq!(to_kebab_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_screaming_snake_case() {
-        let convertable_string: String = "FOO_BAR".to_owned();
-        let expected: String = "foo-bar".to_owned();
-        assert_eq!(to_kebab_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_snake_case() {
-        let convertable_string: String = "foo_bar".to_owned();
-        let expected: String = "foo-bar".to_owned();
-        assert_eq!(to_kebab_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn is_correct_from_camel_case() {
-        let convertable_string: String = "fooBar".to_owned();
-        assert_eq!(is_kebab_case(&convertable_string), false)
-    }
-
-    #[test]
-    fn is_correct_from_pascal_case() {
-        let convertable_string: String = "FooBar".to_owned();
-        assert_eq!(is_kebab_case(&convertable_string), false)
-    }
-
-    #[test]
-    fn is_correct_from_kebab_case() {
-        let convertable_string: String = "foo-bar".to_owned();
-        assert_eq!(is_kebab_case(&convertable_string), true)
-    }
-
-    #[test]
-    fn is_correct_from_sentence_case() {
-        let convertable_string: String = "Foo bar".to_owned();
-        assert_eq!(is_kebab_case(&convertable_string), false)
-    }
-
-    #[test]
-    fn is_correct_from_title_case() {
-        let convertable_string: String = "Foo Bar".to_owned();
-        assert_eq!(is_kebab_case(&convertable_string), false)
-    }
-
-    #[test]
-    fn is_correct_from_train_case() {
-        let convertable_string: String = "Foo-Bar".to_owned();
-        assert_eq!(is_kebab_case(&convertable_string), false)
-    }
-
-    #[test]
-    fn is_correct_from_screaming_snake_case() {
-        let convertable_string: String = "FOO_BAR".to_owned();
-        assert_eq!(is_kebab_case(&convertable_string), false)
-    }
-
-    #[test]
-    fn is_correct_from_snake_case() {
-        let convertable_string: String = "foo_bar".to_owned();
-        assert_eq!(is_kebab_case(&convertable_string), false)
-    }
-}
-
diff --git a/third_party/rust/Inflector/src/cases/mod.rs b/third_party/rust/Inflector/src/cases/mod.rs
deleted file mode 100644
index dfa772e801..0000000000
--- a/third_party/rust/Inflector/src/cases/mod.rs
+++ /dev/null
@@ -1,52 +0,0 @@
-mod case;
-/// Provides conversion to and detection of class case strings.
-///
-/// This version singularizes strings.
-///
-/// Example string `ClassCase`
-pub mod classcase;
-
-/// Provides conversion to and detection of camel case strings.
-///
-/// Example string `camelCase`
-pub mod camelcase;
-
-/// Provides conversion to and detection of snake case strings.
-///
-/// Example string `snake_case`
-pub mod snakecase;
-
-/// Provides conversion to and detection of screaming snake case strings.
-///
-/// Example string `SCREAMING_SNAKE_CASE`
-pub mod screamingsnakecase;
-
-/// Provides conversion to and detection of kebab case strings.
-///
-/// Example string `kebab-case`
-pub mod kebabcase;
-
-/// Provides conversion to and detection of train case strings.
-///
-/// Example string `Train-Case`
-pub mod traincase;
-
-/// Provides conversion to and detection of sentence case strings.
-///
-/// Example string `Sentence case`
-pub mod sentencecase;
-
-/// Provides conversion to and detection of title case strings.
-///
-/// Example string `Title Case`
-pub mod titlecase;
-
-/// Provides conversion to and detection of table case strings.
-///
-/// Example string `table_cases`
-pub mod tablecase;
-
-/// Provides conversion to pascal case strings.
-///
-/// Example string `PascalCase`
-pub mod pascalcase;
diff --git a/third_party/rust/Inflector/src/cases/pascalcase/mod.rs b/third_party/rust/Inflector/src/cases/pascalcase/mod.rs
deleted file mode 100644
index 248f91ab43..0000000000
--- a/third_party/rust/Inflector/src/cases/pascalcase/mod.rs
+++ /dev/null
@@ -1,360 +0,0 @@
-#![deny(warnings)]
-use cases::case::*;
-/// Converts a `&str` to pascalCase `String`
-///
-/// ```
-///     use inflector::cases::pascalcase::to_pascal_case;
-///     let mock_string: &str = "fooBar";
-///     let expected_string: String = "FooBar".to_string();
-///     let asserted_string: String = to_pascal_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::cases::pascalcase::to_pascal_case;
-///     let mock_string: &str = "FOO_BAR";
-///     let expected_string: String = "FooBar".to_string();
-///     let asserted_string: String = to_pascal_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::cases::pascalcase::to_pascal_case;
-///     let mock_string: &str = "Foo Bar";
-///     let expected_string: String = "FooBar".to_string();
-///     let asserted_string: String = to_pascal_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::cases::pascalcase::to_pascal_case;
-///     let mock_string: &str = "foo_bar";
-///     let expected_string: String = "FooBar".to_string();
-///     let asserted_string: String = to_pascal_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::cases::pascalcase::to_pascal_case;
-///     let mock_string: &str = "Foo bar";
-///     let expected_string: String = "FooBar".to_string();
-///     let asserted_string: String = to_pascal_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::cases::pascalcase::to_pascal_case;
-///     let mock_string: &str = "foo-bar";
-///     let expected_string: String = "FooBar".to_string();
-///     let asserted_string: String = to_pascal_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::cases::pascalcase::to_pascal_case;
-///     let mock_string: &str = "FooBar";
-///     let expected_string: String = "FooBar".to_string();
-///     let asserted_string: String = to_pascal_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::cases::pascalcase::to_pascal_case;
-///     let mock_string: &str = "FooBar3";
-///     let expected_string: String = "FooBar3".to_string();
-///     let asserted_string: String = to_pascal_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-pub fn to_pascal_case(non_pascalized_string: &str) -> String {
-    let options = CamelOptions {
-        new_word: true,
-        last_char: ' ',
-        first_word: false,
-        injectable_char: ' ',
-        has_seperator: false,
-        inverted: false,
-    };
-    to_case_camel_like(non_pascalized_string, options)
-}
-
-/// Determines if a `&str` is pascalCase bool``
-///
-/// ```
-///     use inflector::cases::pascalcase::is_pascal_case;
-///     let mock_string: &str = "Foo";
-///     let asserted_bool: bool = is_pascal_case(mock_string);
-///     assert!(asserted_bool == true);
-///
-///
-/// ```
-/// ```
-///     use inflector::cases::pascalcase::is_pascal_case;
-///     let mock_string: &str = "foo";
-///     let asserted_bool: bool = is_pascal_case(mock_string);
-///     assert!(asserted_bool == false);
-///
-///
-/// ```
-/// ```
-///     use inflector::cases::pascalcase::is_pascal_case;
-///     let mock_string: &str = "foo-bar-string-that-is-really-really-long";
-///     let asserted_bool: bool = is_pascal_case(mock_string);
-///     assert!(asserted_bool == false);
-///
-///
-/// ```
-/// ```
-///     use inflector::cases::pascalcase::is_pascal_case;
-///     let mock_string: &str = "FooBarIsAReallyReallyLongString";
-///     let asserted_bool: bool = is_pascal_case(mock_string);
-///     assert!(asserted_bool == true);
-///
-///
-/// ```
-/// ```
-///     use inflector::cases::pascalcase::is_pascal_case;
-///     let mock_string: &str = "FooBarIsAReallyReally3LongString";
-///     let asserted_bool: bool = is_pascal_case(mock_string);
-///     assert!(asserted_bool == true);
-///
-///
-/// ```
-/// ```
-///     use inflector::cases::pascalcase::is_pascal_case;
-///     let mock_string: &str = "FooBarIsAReallyReallyLongString";
-///     let asserted_bool: bool = is_pascal_case(mock_string);
-///     assert!(asserted_bool == true);
-///
-///
-/// ```
-/// ```
-///     use inflector::cases::pascalcase::is_pascal_case;
-///     let mock_string: &str = "FOO_BAR_STRING_THAT_IS_REALLY_REALLY_LONG";
-///     let asserted_bool: bool = is_pascal_case(mock_string);
-///     assert!(asserted_bool == false);
-///
-///
-/// ```
-/// ```
-///     use inflector::cases::pascalcase::is_pascal_case;
-///     let mock_string: &str = "foo_bar_string_that_is_really_really_long";
-///     let asserted_bool: bool = is_pascal_case(mock_string);
-///     assert!(asserted_bool == false);
-///
-///
-/// ```
-/// ```
-///     use inflector::cases::pascalcase::is_pascal_case;
-///     let mock_string: &str = "Foo bar string that is really really long";
-///     let asserted_bool: bool = is_pascal_case(mock_string);
-///     assert!(asserted_bool == false);
-///
-///
-/// ```
-/// ```
-///     use inflector::cases::pascalcase::is_pascal_case;
-///     let mock_string: &str = "Foo Bar Is A Really Really Long String";
-///     let asserted_bool: bool = is_pascal_case(mock_string);
-///     assert!(asserted_bool == false);
-/// ```
-pub fn is_pascal_case(test_string: &str) -> bool {
-    to_pascal_case(test_string.clone()) == test_string
-}
-
-#[cfg(all(feature = "unstable", test))]
-mod benchmarks {
-    extern crate test;
-    use self::test::Bencher;
-
-    #[bench]
-    fn bench_pascal0(b: &mut Bencher) {
-        b.iter(|| {
-            let test_string = "Foo bar";
-            super::to_pascal_case(test_string)
-        });
-    }
-
-    #[bench]
-    fn bench_pascal1(b: &mut Bencher) {
-        b.iter(|| {
-            let test_string = "foo_bar";
-            super::to_pascal_case(test_string)
-        });
-    }
-
-    #[bench]
-    fn bench_pascal2(b: &mut Bencher) {
-        b.iter(|| {
-            let test_string = "fooBar";
-            super::to_pascal_case(test_string)
-        });
-    }
-
-    #[bench]
-    fn bench_is_pascal(b: &mut Bencher) {
-        b.iter(|| {
-            let test_string: &str = "Foo bar";
-            super::is_pascal_case(test_string)
-        });
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use ::to_pascal_case;
-    use ::is_pascal_case;
-
-    #[test]
-    fn from_camel_case() {
-        let convertable_string: String = "fooBar".to_owned();
-        let expected: String = "FooBar".to_owned();
-        assert_eq!(to_pascal_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_pascal_case() {
-        let convertable_string: String = "FooBar".to_owned();
-        let expected: String = "FooBar".to_owned();
-        assert_eq!(to_pascal_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_kebab_case() {
-        let convertable_string: String = "foo-bar".to_owned();
-        let expected: String = "FooBar".to_owned();
-        assert_eq!(to_pascal_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_sentence_case() {
-        let convertable_string: String = "Foo bar".to_owned();
-        let expected: String = "FooBar".to_owned();
-        assert_eq!(to_pascal_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_title_case() {
-        let convertable_string: String = "Foo Bar".to_owned();
-        let expected: String = "FooBar".to_owned();
-        assert_eq!(to_pascal_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_train_case() {
-        let convertable_string: String = "Foo-Bar".to_owned();
-        let expected: String = "FooBar".to_owned();
-        assert_eq!(to_pascal_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_screaming_snake_case() {
-        let convertable_string: String = "FOO_BAR".to_owned();
-        let expected: String = "FooBar".to_owned();
-        assert_eq!(to_pascal_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_snake_case() {
-        let convertable_string: String = "foo_bar".to_owned();
-        let expected: String = "FooBar".to_owned();
-        assert_eq!(to_pascal_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_case_with_loads_of_space() {
-        let convertable_string: String = "foo           bar".to_owned();
-        let expected: String = "FooBar".to_owned();
-        assert_eq!(to_pascal_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn a_name_with_a_dot() {
-        let convertable_string: String = "Robert C. Martin".to_owned();
-        let expected: String = "RobertCMartin".to_owned();
-        assert_eq!(to_pascal_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn random_text_with_bad_chars() {
-        let convertable_string: String = "Random text with *(bad) chars".to_owned();
-        let expected: String = "RandomTextWithBadChars".to_owned();
-        assert_eq!(to_pascal_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn trailing_bad_chars() {
-        let convertable_string: String = "trailing bad_chars*(()())".to_owned();
-        let expected: String = "TrailingBadChars".to_owned();
-        assert_eq!(to_pascal_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn leading_bad_chars() {
-        let convertable_string: String = "-!#$%leading bad chars".to_owned();
-        let expected: String = "LeadingBadChars".to_owned();
-        assert_eq!(to_pascal_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn wrapped_in_bad_chars() {
-        let convertable_string: String = "-!#$%wrapped in bad chars&*^*&(&*^&(<><?>><?><>))".to_owned();
-        let expected: String = "WrappedInBadChars".to_owned();
-        assert_eq!(to_pascal_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn has_a_sign() {
-        let convertable_string: String = "has a + sign".to_owned();
-        let expected: String = "HasASign".to_owned();
-        assert_eq!(to_pascal_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn is_correct_from_camel_case() {
-        let convertable_string: String = "fooBar".to_owned();
-        assert_eq!(is_pascal_case(&convertable_string), false)
-    }
-
-    #[test]
-    fn is_correct_from_pascal_case() {
-        let convertable_string: String = "FooBar".to_owned();
-        assert_eq!(is_pascal_case(&convertable_string), true)
-    }
-
-    #[test]
-    fn is_correct_from_kebab_case() {
-        let convertable_string: String = "foo-bar".to_owned();
-        assert_eq!(is_pascal_case(&convertable_string), false)
-    }
-
-    #[test]
-    fn is_correct_from_sentence_case() {
-        let convertable_string: String = "Foo bar".to_owned();
-        assert_eq!(is_pascal_case(&convertable_string), false)
-    }
-
-    #[test]
-    fn is_correct_from_title_case() {
-        let convertable_string: String = "Foo Bar".to_owned();
-        assert_eq!(is_pascal_case(&convertable_string), false)
-    }
-
-    #[test]
-    fn is_correct_from_train_case() {
-        let convertable_string: String = "Foo-Bar".to_owned();
-        assert_eq!(is_pascal_case(&convertable_string), false)
-    }
-
-    #[test]
-    fn is_correct_from_screaming_snake_case() {
-        let convertable_string: String = "FOO_BAR".to_owned();
-        assert_eq!(is_pascal_case(&convertable_string), false)
-    }
-
-    #[test]
-    fn is_correct_from_snake_case() {
-        let convertable_string: String = "foo_bar".to_owned();
-        assert_eq!(is_pascal_case(&convertable_string), false)
-    }
-}
diff --git a/third_party/rust/Inflector/src/cases/screamingsnakecase/mod.rs b/third_party/rust/Inflector/src/cases/screamingsnakecase/mod.rs
deleted file mode 100644
index 9bec7a5536..0000000000
--- a/third_party/rust/Inflector/src/cases/screamingsnakecase/mod.rs
+++ /dev/null
@@ -1,253 +0,0 @@
-#![deny(warnings)]
-use cases::case::*;
-/// Converts a `&str` to `SCREAMING_SNAKE_CASE` `String`
-///
-/// ```
-///     use inflector::cases::screamingsnakecase::to_screaming_snake_case;
-///     let mock_string: &str = "foo_bar";
-///     let expected_string: String = "FOO_BAR".to_string();
-///     let asserted_string: String = to_screaming_snake_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::cases::screamingsnakecase::to_screaming_snake_case;
-///     let mock_string: &str = "HTTP Foo bar";
-///     let expected_string: String = "HTTP_FOO_BAR".to_string();
-///     let asserted_string: String = to_screaming_snake_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::cases::screamingsnakecase::to_screaming_snake_case;
-///     let mock_string: &str = "Foo bar";
-///     let expected_string: String = "FOO_BAR".to_string();
-///     let asserted_string: String = to_screaming_snake_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::cases::screamingsnakecase::to_screaming_snake_case;
-///     let mock_string: &str = "Foo Bar";
-///     let expected_string: String = "FOO_BAR".to_string();
-///     let asserted_string: String = to_screaming_snake_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::cases::screamingsnakecase::to_screaming_snake_case;
-///     let mock_string: &str = "FooBar";
-///     let expected_string: String = "FOO_BAR".to_string();
-///     let asserted_string: String = to_screaming_snake_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::cases::screamingsnakecase::to_screaming_snake_case;
-///     let mock_string: &str = "fooBar";
-///     let expected_string: String = "FOO_BAR".to_string();
-///     let asserted_string: String = to_screaming_snake_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::cases::screamingsnakecase::to_screaming_snake_case;
-///     let mock_string: &str = "fooBar3";
-///     let expected_string: String = "FOO_BAR_3".to_string();
-///     let asserted_string: String = to_screaming_snake_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-pub fn to_screaming_snake_case(non_snake_case_string: &str) -> String {
-    to_case_snake_like(non_snake_case_string, "_", "upper")
-}
-
-/// Determines of a `&str` is `SCREAMING_SNAKE_CASE`
-///
-/// ```
-///     use inflector::cases::screamingsnakecase::is_screaming_snake_case;
-///     let mock_string: &str = "Foo bar string that is really really long";
-///     let asserted_bool: bool = is_screaming_snake_case(mock_string);
-///     assert!(asserted_bool == false);
-///
-/// ```
-/// ```
-///     use inflector::cases::screamingsnakecase::is_screaming_snake_case;
-///     let mock_string: &str = "foo-bar-string-that-is-really-really-long";
-///     let asserted_bool: bool = is_screaming_snake_case(mock_string);
-///     assert!(asserted_bool == false);
-///
-/// ```
-/// ```
-///     use inflector::cases::screamingsnakecase::is_screaming_snake_case;
-///     let mock_string: &str = "FooBarIsAReallyReallyLongString";
-///     let asserted_bool: bool = is_screaming_snake_case(mock_string);
-///     assert!(asserted_bool == false);
-///
-/// ```
-/// ```
-///     use inflector::cases::screamingsnakecase::is_screaming_snake_case;
-///     let mock_string: &str = "Foo Bar Is A Really Really Long String";
-///     let asserted_bool: bool = is_screaming_snake_case(mock_string);
-///     assert!(asserted_bool == false);
-///
-/// ```
-/// ```
-///     use inflector::cases::screamingsnakecase::is_screaming_snake_case;
-///     let mock_string: &str = "fooBarIsAReallyReallyLongString";
-///     let asserted_bool: bool = is_screaming_snake_case(mock_string);
-///     assert!(asserted_bool == false);
-///
-/// ```
-/// ```
-///     use inflector::cases::screamingsnakecase::is_screaming_snake_case;
-///     let mock_string: &str = "FOO_BAR_STRING_THAT_IS_REALLY_REALLY_LONG";
-///     let asserted_bool: bool = is_screaming_snake_case(mock_string);
-///     assert!(asserted_bool == true);
-///
-/// ```
-/// ```
-///     use inflector::cases::screamingsnakecase::is_screaming_snake_case;
-///     let mock_string: &str = "FOO_BAR1_STRING_THAT_IS_REALLY_REALLY_LONG";
-///     let asserted_bool: bool = is_screaming_snake_case(mock_string);
-///     assert!(asserted_bool == true);
-///
-/// ```
-/// ```
-///     use inflector::cases::screamingsnakecase::is_screaming_snake_case;
-///     let mock_string: &str = "FOO_BAR_1_STRING_THAT_IS_REALLY_REALLY_LONG";
-///     let asserted_bool: bool = is_screaming_snake_case(mock_string);
-///     assert!(asserted_bool == true);
-///
-/// ```
-pub fn is_screaming_snake_case(test_string: &str) -> bool {
-    test_string == to_screaming_snake_case(test_string.clone())
-}
-
-
-#[cfg(all(feature = "unstable", test))]
-mod benchmarks {
-    extern crate test;
-    use self::test::Bencher;
-
-    #[bench]
-    fn bench_screaming_snake(b: &mut Bencher) {
-        b.iter(|| super::to_screaming_snake_case("Foo bar"));
-    }
-
-    #[bench]
-    fn bench_is_screaming_snake(b: &mut Bencher) {
-        b.iter(|| super::is_screaming_snake_case("Foo bar"));
-    }
-
-}
-
-#[cfg(test)]
-mod tests {
-    use ::to_screaming_snake_case;
-    use ::is_screaming_snake_case;
-
-    #[test]
-    fn from_camel_case() {
-        let convertable_string: String = "fooBar".to_owned();
-        let expected: String = "FOO_BAR".to_owned();
-        assert_eq!(to_screaming_snake_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_pascal_case() {
-        let convertable_string: String = "FooBar".to_owned();
-        let expected: String = "FOO_BAR".to_owned();
-        assert_eq!(to_screaming_snake_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_kebab_case() {
-        let convertable_string: String = "foo-bar".to_owned();
-        let expected: String = "FOO_BAR".to_owned();
-        assert_eq!(to_screaming_snake_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_sentence_case() {
-        let convertable_string: String = "Foo bar".to_owned();
-        let expected: String = "FOO_BAR".to_owned();
-        assert_eq!(to_screaming_snake_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_title_case() {
-        let convertable_string: String = "Foo Bar".to_owned();
-        let expected: String = "FOO_BAR".to_owned();
-        assert_eq!(to_screaming_snake_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_train_case() {
-        let convertable_string: String = "Foo-Bar".to_owned();
-        let expected: String = "FOO_BAR".to_owned();
-        assert_eq!(to_screaming_snake_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_screaming_screaming_snake_case() {
-        let convertable_string: String = "FOO_BAR".to_owned();
-        let expected: String = "FOO_BAR".to_owned();
-        assert_eq!(to_screaming_snake_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_snake_case() {
-        let convertable_string: String = "foo_bar".to_owned();
-        let expected: String = "FOO_BAR".to_owned();
-        assert_eq!(to_screaming_snake_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn is_correct_from_camel_case() {
-        let convertable_string: String = "fooBar".to_owned();
-        assert_eq!(is_screaming_snake_case(&convertable_string), false)
-    }
-
-    #[test]
-    fn is_correct_from_pascal_case() {
-        let convertable_string: String = "FooBar".to_owned();
-        assert_eq!(is_screaming_snake_case(&convertable_string), false)
-    }
-
-    #[test]
-    fn is_correct_from_kebab_case() {
-        let convertable_string: String = "foo-bar".to_owned();
-        assert_eq!(is_screaming_snake_case(&convertable_string), false)
-    }
-
-    #[test]
-    fn is_correct_from_sentence_case() {
-        let convertable_string: String = "Foo bar".to_owned();
-        assert_eq!(is_screaming_snake_case(&convertable_string), false)
-    }
-
-    #[test]
-    fn is_correct_from_title_case() {
-        let convertable_string: String = "Foo Bar".to_owned();
-        assert_eq!(is_screaming_snake_case(&convertable_string), false)
-    }
-
-    #[test]
-    fn is_correct_from_train_case() {
-        let convertable_string: String = "Foo-Bar".to_owned();
-        assert_eq!(is_screaming_snake_case(&convertable_string), false)
-    }
-
-    #[test]
-    fn is_correct_from_screaming_screaming_snake_case() {
-        let convertable_string: String = "FOO_BAR".to_owned();
-        assert_eq!(is_screaming_snake_case(&convertable_string), true)
-    }
-
-    #[test]
-    fn is_correct_from_snake_case() {
-        let convertable_string: String = "foo_bar".to_owned();
-        assert_eq!(is_screaming_snake_case(&convertable_string), false)
-    }
-}
diff --git a/third_party/rust/Inflector/src/cases/sentencecase/mod.rs b/third_party/rust/Inflector/src/cases/sentencecase/mod.rs
deleted file mode 100644
index 5a99d217f4..0000000000
--- a/third_party/rust/Inflector/src/cases/sentencecase/mod.rs
+++ /dev/null
@@ -1,313 +0,0 @@
-#![deny(warnings)]
-use cases::case::*;
-/// Converts a `&str` to `Sentence case` `String`
-///
-/// ```
-///     use inflector::cases::sentencecase::to_sentence_case;
-///     let mock_string: &str = "Foo bar";
-///     let expected_string: String = "Foo bar".to_string();
-///     let asserted_string: String = to_sentence_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::cases::sentencecase::to_sentence_case;
-///     let mock_string: &str = "FooBar";
-///     let expected_string: String = "Foo bar".to_string();
-///     let asserted_string: String = to_sentence_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::cases::sentencecase::to_sentence_case;
-///     let mock_string: &str = "fooBar";
-///     let expected_string: String = "Foo bar".to_string();
-///     let asserted_string: String = to_sentence_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::cases::sentencecase::to_sentence_case;
-///     let mock_string: &str = "FOO_BAR";
-///     let expected_string: String = "Foo bar".to_string();
-///     let asserted_string: String = to_sentence_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::cases::sentencecase::to_sentence_case;
-///     let mock_string: &str = "foo_bar";
-///     let expected_string: String = "Foo bar".to_string();
-///     let asserted_string: String = to_sentence_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::cases::sentencecase::to_sentence_case;
-///     let mock_string: &str = "foo-bar";
-///     let expected_string: String = "Foo bar".to_string();
-///     let asserted_string: String = to_sentence_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-pub fn to_sentence_case(non_sentence_case_string: &str) -> String {
-    let options = CamelOptions {
-        new_word: true,
-        last_char: ' ',
-        first_word: true,
-        injectable_char: ' ',
-        has_seperator: true,
-        inverted: true,
-    };
-    to_case_camel_like(non_sentence_case_string, options)
-}
-/// Determines of a `&str` is `Sentence case`
-///
-/// ```
-///     use inflector::cases::sentencecase::is_sentence_case;
-///     let mock_string: &str = "foo-bar-string-that-is-really-really-long";
-///     let asserted_bool: bool = is_sentence_case(mock_string);
-///     assert!(asserted_bool == false);
-///
-/// ```
-/// ```
-///     use inflector::cases::sentencecase::is_sentence_case;
-///     let mock_string: &str = "FooBarIsAReallyReallyLongString";
-///     let asserted_bool: bool = is_sentence_case(mock_string);
-///     assert!(asserted_bool == false);
-///
-/// ```
-/// ```
-///     use inflector::cases::sentencecase::is_sentence_case;
-///     let mock_string: &str = "fooBarIsAReallyReallyLongString";
-///     let asserted_bool: bool = is_sentence_case(mock_string);
-///     assert!(asserted_bool == false);
-///
-/// ```
-/// ```
-///     use inflector::cases::sentencecase::is_sentence_case;
-///     let mock_string: &str = "Foo Bar Is A Really Really Long String";
-///     let asserted_bool: bool = is_sentence_case(mock_string);
-///     assert!(asserted_bool == false);
-///
-/// ```
-/// ```
-///     use inflector::cases::sentencecase::is_sentence_case;
-///     let mock_string: &str = "FOO_BAR_STRING_THAT_IS_REALLY_REALLY_LONG";
-///     let asserted_bool: bool = is_sentence_case(mock_string);
-///     assert!(asserted_bool == false);
-///
-/// ```
-/// ```
-///     use inflector::cases::sentencecase::is_sentence_case;
-///     let mock_string: &str = "foo_bar_string_that_is_really_really_long";
-///     let asserted_bool: bool = is_sentence_case(mock_string);
-///     assert!(asserted_bool == false);
-///
-/// ```
-/// ```
-///     use inflector::cases::sentencecase::is_sentence_case;
-///     let mock_string: &str = "Foo";
-///     let asserted_bool: bool = is_sentence_case(mock_string);
-///     assert!(asserted_bool == true);
-///
-/// ```
-/// ```
-///     use inflector::cases::sentencecase::is_sentence_case;
-///     let mock_string: &str = "foo";
-///     let asserted_bool: bool = is_sentence_case(mock_string);
-///     assert!(asserted_bool == false);
-///
-/// ```
-/// ```
-///     use inflector::cases::sentencecase::is_sentence_case;
-///     let mock_string: &str = "Foo bar string that is really really long";
-///     let asserted_bool: bool = is_sentence_case(mock_string);
-///     assert!(asserted_bool == true);
-///
-/// ```
-pub fn is_sentence_case(test_string: &str) -> bool {
-    test_string == to_sentence_case(test_string.clone())
-}
-
-#[cfg(all(feature = "unstable", test))]
-mod benchmarks {
-    extern crate test;
-    use self::test::Bencher;
-
-    #[bench]
-    fn bench_sentence(b: &mut Bencher) {
-        b.iter(|| super::to_sentence_case("Foo BAR"));
-    }
-
-    #[bench]
-    fn bench_is_sentence(b: &mut Bencher) {
-        b.iter(|| super::is_sentence_case("Foo bar"));
-    }
-
-    #[bench]
-    fn bench_sentence_from_snake(b: &mut Bencher) {
-        b.iter(|| super::to_sentence_case("foo_bar"));
-    }
-
-}
-
-#[cfg(test)]
-mod tests {
-    use ::to_sentence_case;
-    use ::is_sentence_case;
-
-    #[test]
-    fn from_camel_case() {
-        let convertable_string: String = "fooBar".to_owned();
-        let expected: String = "Foo bar".to_owned();
-        assert_eq!(to_sentence_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_pascal_case() {
-        let convertable_string: String = "FooBar".to_owned();
-        let expected: String = "Foo bar".to_owned();
-        assert_eq!(to_sentence_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_kebab_case() {
-        let convertable_string: String = "foo-bar".to_owned();
-        let expected: String = "Foo bar".to_owned();
-        assert_eq!(to_sentence_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_sentence_case() {
-        let convertable_string: String = "Foo bar".to_owned();
-        let expected: String = "Foo bar".to_owned();
-        assert_eq!(to_sentence_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_title_case() {
-        let convertable_string: String = "Foo Bar".to_owned();
-        let expected: String = "Foo bar".to_owned();
-        assert_eq!(to_sentence_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_train_case() {
-        let convertable_string: String = "Foo-Bar".to_owned();
-        let expected: String = "Foo bar".to_owned();
-        assert_eq!(to_sentence_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_screaming_snake_case() {
-        let convertable_string: String = "FOO_BAR".to_owned();
-        let expected: String = "Foo bar".to_owned();
-        assert_eq!(to_sentence_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_snake_case() {
-        let convertable_string: String = "foo_bar".to_owned();
-        let expected: String = "Foo bar".to_owned();
-        assert_eq!(to_sentence_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_case_with_loads_of_space() {
-        let convertable_string: String = "foo           bar".to_owned();
-        let expected: String = "Foo bar".to_owned();
-        assert_eq!(to_sentence_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn a_name_with_a_dot() {
-        let convertable_string: String = "Robert C. Martin".to_owned();
-        let expected: String = "Robert c martin".to_owned();
-        assert_eq!(to_sentence_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn random_text_with_bad_chars() {
-        let convertable_string: String = "Random text with *(bad) chars".to_owned();
-        let expected: String = "Random text with bad chars".to_owned();
-        assert_eq!(to_sentence_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn trailing_bad_chars() {
-        let convertable_string: String = "trailing bad_chars*(()())".to_owned();
-        let expected: String = "Trailing bad chars".to_owned();
-        assert_eq!(to_sentence_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn leading_bad_chars() {
-        let convertable_string: String = "-!#$%leading bad chars".to_owned();
-        let expected: String = "Leading bad chars".to_owned();
-        assert_eq!(to_sentence_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn wrapped_in_bad_chars() {
-        let convertable_string: String = "-!#$%wrapped in bad chars&*^*&(&*^&(<><?>><?><>))".to_owned();
-        let expected: String = "Wrapped in bad chars".to_owned();
-        assert_eq!(to_sentence_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn has_a_sign() {
-        let convertable_string: String = "has a + sign".to_owned();
-        let expected: String = "Has a sign".to_owned();
-        assert_eq!(to_sentence_case(&convertable_string), expected)
-    }
-
-
-    #[test]
-    fn is_correct_from_camel_case() {
-        let convertable_string: String = "fooBar".to_owned();
-        assert_eq!(is_sentence_case(&convertable_string), false)
-    }
-
-    #[test]
-    fn is_correct_from_pascal_case() {
-        let convertable_string: String = "FooBar".to_owned();
-        assert_eq!(is_sentence_case(&convertable_string), false)
-    }
-
-    #[test]
-    fn is_correct_from_kebab_case() {
-        let convertable_string: String = "foo-bar".to_owned();
-        assert_eq!(is_sentence_case(&convertable_string), false)
-    }
-
-    #[test]
-    fn is_correct_from_sentence_case() {
-        let convertable_string: String = "Foo bar".to_owned();
-        assert_eq!(is_sentence_case(&convertable_string), true)
-    }
-
-    #[test]
-    fn is_correct_from_title_case() {
-        let convertable_string: String = "Foo Bar".to_owned();
-        assert_eq!(is_sentence_case(&convertable_string), false)
-    }
-
-    #[test]
-    fn is_correct_from_train_case() {
-        let convertable_string: String = "Foo-Bar".to_owned();
-        assert_eq!(is_sentence_case(&convertable_string), false)
-    }
-
-    #[test]
-    fn is_correct_from_screaming_snake_case() {
-        let convertable_string: String = "FOO_BAR".to_owned();
-        assert_eq!(is_sentence_case(&convertable_string), false)
-    }
-
-    #[test]
-    fn is_correct_from_snake_case() {
-        let convertable_string: String = "foo_bar".to_owned();
-        assert_eq!(is_sentence_case(&convertable_string), false)
-    }
-}
diff --git a/third_party/rust/Inflector/src/cases/snakecase/mod.rs b/third_party/rust/Inflector/src/cases/snakecase/mod.rs
deleted file mode 100644
index a56894b1a1..0000000000
--- a/third_party/rust/Inflector/src/cases/snakecase/mod.rs
+++ /dev/null
@@ -1,334 +0,0 @@
-#![deny(warnings)]
-use cases::case::*;
-/// Converts a `&str` to `snake_case` `String`
-///
-/// ```
-///     use inflector::cases::snakecase::to_snake_case;
-///     let mock_string: &str = "foo_bar";
-///     let expected_string: String = "foo_bar".to_string();
-///     let asserted_string: String = to_snake_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::cases::snakecase::to_snake_case;
-///     let mock_string: &str = "HTTP Foo bar";
-///     let expected_string: String = "http_foo_bar".to_string();
-///     let asserted_string: String = to_snake_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::cases::snakecase::to_snake_case;
-///     let mock_string: &str = "HTTPFooBar";
-///     let expected_string: String = "http_foo_bar".to_string();
-///     let asserted_string: String = to_snake_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::cases::snakecase::to_snake_case;
-///     let mock_string: &str = "Foo bar";
-///     let expected_string: String = "foo_bar".to_string();
-///     let asserted_string: String = to_snake_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::cases::snakecase::to_snake_case;
-///     let mock_string: &str = "Foo Bar";
-///     let expected_string: String = "foo_bar".to_string();
-///     let asserted_string: String = to_snake_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::cases::snakecase::to_snake_case;
-///     let mock_string: &str = "FooBar";
-///     let expected_string: String = "foo_bar".to_string();
-///     let asserted_string: String = to_snake_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::cases::snakecase::to_snake_case;
-///     let mock_string: &str = "FOO_BAR";
-///     let expected_string: String = "foo_bar".to_string();
-///     let asserted_string: String = to_snake_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::cases::snakecase::to_snake_case;
-///     let mock_string: &str = "fooBar";
-///     let expected_string: String = "foo_bar".to_string();
-///     let asserted_string: String = to_snake_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::cases::snakecase::to_snake_case;
-///     let mock_string: &str = "fooBar3";
-///     let expected_string: String = "foo_bar_3".to_string();
-///     let asserted_string: String = to_snake_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-pub fn to_snake_case(non_snake_case_string: &str) -> String {
-    to_case_snake_like(non_snake_case_string, "_", "lower")
-}
-
-/// Determines of a `&str` is `snake_case`
-///
-/// ```
-///     use inflector::cases::snakecase::is_snake_case;
-///     let mock_string: &str = "Foo bar string that is really really long";
-///     let asserted_bool: bool = is_snake_case(mock_string);
-///     assert!(asserted_bool == false);
-///
-/// ```
-/// ```
-///     use inflector::cases::snakecase::is_snake_case;
-///     let mock_string: &str = "foo-bar-string-that-is-really-really-long";
-///     let asserted_bool: bool = is_snake_case(mock_string);
-///     assert!(asserted_bool == false);
-///
-/// ```
-/// ```
-///     use inflector::cases::snakecase::is_snake_case;
-///     let mock_string: &str = "FooBarIsAReallyReallyLongString";
-///     let asserted_bool: bool = is_snake_case(mock_string);
-///     assert!(asserted_bool == false);
-///
-/// ```
-/// ```
-///     use inflector::cases::snakecase::is_snake_case;
-///     let mock_string: &str = "Foo Bar Is A Really Really Long String";
-///     let asserted_bool: bool = is_snake_case(mock_string);
-///     assert!(asserted_bool == false);
-///
-/// ```
-/// ```
-///     use inflector::cases::snakecase::is_snake_case;
-///     let mock_string: &str = "FOO_BAR_IS_A_REALLY_REALLY_LONG_STRING";
-///     let asserted_bool: bool = is_snake_case(mock_string);
-///     assert!(asserted_bool == false);
-///
-/// ```
-/// ```
-///     use inflector::cases::snakecase::is_snake_case;
-///     let mock_string: &str = "fooBarIsAReallyReallyLongString";
-///     let asserted_bool: bool = is_snake_case(mock_string);
-///     assert!(asserted_bool == false);
-///
-/// ```
-/// ```
-///     use inflector::cases::snakecase::is_snake_case;
-///     let mock_string: &str = "foo_bar_string_that_is_really_really_long";
-///     let asserted_bool: bool = is_snake_case(mock_string);
-///     assert!(asserted_bool == true);
-///
-/// ```
-/// ```
-///     use inflector::cases::snakecase::is_snake_case;
-///     let mock_string: &str = "foo_bar1_string_that_is_really_really_long";
-///     let asserted_bool: bool = is_snake_case(mock_string);
-///     assert!(asserted_bool == false);
-///
-/// ```
-/// ```
-///     use inflector::cases::snakecase::is_snake_case;
-///     let mock_string: &str = "foo_bar_1_string_that_is_really_really_long";
-///     let asserted_bool: bool = is_snake_case(mock_string);
-///     assert!(asserted_bool == true);
-///
-/// ```
-pub fn is_snake_case(test_string: &str) -> bool {
-    test_string == to_snake_case(test_string.clone())
-}
-
-#[cfg(all(feature = "unstable", test))]
-mod benchmarks {
-    extern crate test;
-    use self::test::Bencher;
-
-    #[bench]
-    fn bench_snake_from_title(b: &mut Bencher) {
-        b.iter(|| super::to_snake_case("Foo bar"));
-    }
-
-    #[bench]
-    fn bench_snake_from_camel(b: &mut Bencher) {
-        b.iter(|| super::to_snake_case("fooBar"));
-    }
-
-    #[bench]
-    fn bench_snake_from_snake(b: &mut Bencher) {
-        b.iter(|| super::to_snake_case("foo_bar_bar_bar"));
-    }
-
-    #[bench]
-    fn bench_is_snake(b: &mut Bencher) {
-        b.iter(|| super::is_snake_case("Foo bar"));
-    }
-
-}
-
-#[cfg(test)]
-mod tests {
-    use ::to_snake_case;
-    use ::is_snake_case;
-
-    #[test]
-    fn from_camel_case() {
-        let convertable_string: String = "fooBar".to_owned();
-        let expected: String = "foo_bar".to_owned();
-        assert_eq!(to_snake_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_pascal_case() {
-        let convertable_string: String = "FooBar".to_owned();
-        let expected: String = "foo_bar".to_owned();
-        assert_eq!(to_snake_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_kebab_case() {
-        let convertable_string: String = "foo-bar".to_owned();
-        let expected: String = "foo_bar".to_owned();
-        assert_eq!(to_snake_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_sentence_case() {
-        let convertable_string: String = "Foo bar".to_owned();
-        let expected: String = "foo_bar".to_owned();
-        assert_eq!(to_snake_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_title_case() {
-        let convertable_string: String = "Foo Bar".to_owned();
-        let expected: String = "foo_bar".to_owned();
-        assert_eq!(to_snake_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_train_case() {
-        let convertable_string: String = "Foo-Bar".to_owned();
-        let expected: String = "foo_bar".to_owned();
-        assert_eq!(to_snake_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_screaming_snake_case() {
-        let convertable_string: String = "FOO_BAR".to_owned();
-        let expected: String = "foo_bar".to_owned();
-        assert_eq!(to_snake_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_snake_case() {
-        let convertable_string: String = "foo_bar".to_owned();
-        let expected: String = "foo_bar".to_owned();
-        assert_eq!(to_snake_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_case_with_loads_of_space() {
-        let convertable_string: String = "foo           bar".to_owned();
-        let expected: String = "foo_bar".to_owned();
-        assert_eq!(to_snake_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn a_name_with_a_dot() {
-        let convertable_string: String = "Robert C. Martin".to_owned();
-        let expected: String = "robert_c_martin".to_owned();
-        assert_eq!(to_snake_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn random_text_with_bad_chars() {
-        let convertable_string: String = "Random text with *(bad) chars".to_owned();
-        let expected: String = "random_text_with_bad_chars".to_owned();
-        assert_eq!(to_snake_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn trailing_bad_chars() {
-        let convertable_string: String = "trailing bad_chars*(()())".to_owned();
-        let expected: String = "trailing_bad_chars".to_owned();
-        assert_eq!(to_snake_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn leading_bad_chars() {
-        let convertable_string: String = "-!#$%leading bad chars".to_owned();
-        let expected: String = "leading_bad_chars".to_owned();
-        assert_eq!(to_snake_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn wrapped_in_bad_chars() {
-        let convertable_string: String = "-!#$%wrapped in bad chars&*^*&(&*^&(<><?>><?><>))".to_owned();
-        let expected: String = "wrapped_in_bad_chars".to_owned();
-        assert_eq!(to_snake_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn has_a_sign() {
-        let convertable_string: String = "has a + sign".to_owned();
-        let expected: String = "has_a_sign".to_owned();
-        assert_eq!(to_snake_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn is_correct_from_camel_case() {
-        let convertable_string: String = "fooBar".to_owned();
-        assert_eq!(is_snake_case(&convertable_string), false)
-    }
-
-    #[test]
-    fn is_correct_from_pascal_case() {
-        let convertable_string: String = "FooBar".to_owned();
-        assert_eq!(is_snake_case(&convertable_string), false)
-    }
-
-    #[test]
-    fn is_correct_from_kebab_case() {
-        let convertable_string: String = "foo-bar".to_owned();
-        assert_eq!(is_snake_case(&convertable_string), false)
-    }
-
-    #[test]
-    fn is_correct_from_sentence_case() {
-        let convertable_string: String = "Foo bar".to_owned();
-        assert_eq!(is_snake_case(&convertable_string), false)
-    }
-
-    #[test]
-    fn is_correct_from_title_case() {
-        let convertable_string: String = "Foo Bar".to_owned();
-        assert_eq!(is_snake_case(&convertable_string), false)
-    }
-
-    #[test]
-    fn is_correct_from_train_case() {
-        let convertable_string: String = "Foo-Bar".to_owned();
-        assert_eq!(is_snake_case(&convertable_string), false)
-    }
-
-    #[test]
-    fn is_correct_from_screaming_snake_case() {
-        let convertable_string: String = "FOO_BAR".to_owned();
-        assert_eq!(is_snake_case(&convertable_string), false)
-    }
-
-    #[test]
-    fn is_correct_from_snake_case() {
-        let convertable_string: String = "foo_bar".to_owned();
-        assert_eq!(is_snake_case(&convertable_string), true)
-    }
-}
diff --git a/third_party/rust/Inflector/src/cases/tablecase/mod.rs b/third_party/rust/Inflector/src/cases/tablecase/mod.rs
deleted file mode 100644
index 7224cc439b..0000000000
--- a/third_party/rust/Inflector/src/cases/tablecase/mod.rs
+++ /dev/null
@@ -1,271 +0,0 @@
-#![deny(warnings)]
-#[cfg(feature = "heavyweight")]
-use string::pluralize::to_plural;
-#[cfg(feature = "heavyweight")]
-use cases::case::*;
-#[cfg(feature = "heavyweight")]
-/// Converts a `&str` to `table-case` `String`
-///
-/// ```
-/// use inflector::cases::tablecase::to_table_case;
-/// let mock_string: &str = "foo-bar";
-/// let expected_string: String = "foo_bars".to_string();
-/// let asserted_string: String = to_table_case(mock_string);
-/// assert!(asserted_string == expected_string);
-/// ```
-///
-/// ```
-/// use inflector::cases::tablecase::to_table_case;
-/// let mock_string: &str = "FOO_BAR";
-/// let expected_string: String = "foo_bars".to_string();
-/// let asserted_string: String = to_table_case(mock_string);
-/// assert!(asserted_string == expected_string);
-/// ```
-///
-/// ```
-/// use inflector::cases::tablecase::to_table_case;
-/// let mock_string: &str = "foo_bar";
-/// let expected_string: String = "foo_bars".to_string();
-/// let asserted_string: String = to_table_case(mock_string);
-/// assert!(asserted_string == expected_string);
-/// ```
-///
-/// ```
-/// use inflector::cases::tablecase::to_table_case;
-/// let mock_string: &str = "Foo Bar";
-/// let expected_string: String = "foo_bars".to_string();
-/// let asserted_string: String = to_table_case(mock_string);
-/// assert!(asserted_string == expected_string);
-/// ```
-///
-/// ```
-/// use inflector::cases::tablecase::to_table_case;
-/// let mock_string: &str = "Foo bar";
-/// let expected_string: String = "foo_bars".to_string();
-/// let asserted_string: String = to_table_case(mock_string);
-/// assert!(asserted_string == expected_string);
-/// ```
-///
-/// ```
-/// use inflector::cases::tablecase::to_table_case;
-/// let mock_string: &str = "FooBar";
-/// let expected_string: String = "foo_bars".to_string();
-/// let asserted_string: String = to_table_case(mock_string);
-/// assert!(asserted_string == expected_string);
-/// ```
-///
-/// ```
-/// use inflector::cases::tablecase::to_table_case;
-/// let mock_string: &str = "fooBar";
-/// let expected_string: String = "foo_bars".to_string();
-/// let asserted_string: String = to_table_case(mock_string);
-/// assert!(asserted_string == expected_string);
-/// ```
-pub fn to_table_case(non_table_case_string: &str) -> String {
-    let snaked: String = to_case_snake_like(non_table_case_string, "_", "lower");
-    let split: (&str, &str) = snaked.split_at(snaked.rfind('_').unwrap_or(0));
-    format!("{}{}", split.0, to_plural(split.1))
-}
-
-#[cfg(feature = "heavyweight")]
-/// Determines if a `&str` is `table-case`
-///
-/// ```
-///     use inflector::cases::tablecase::is_table_case;
-///     let mock_string: &str = "foo_bar_strings";
-///     let asserted_bool: bool = is_table_case(mock_string);
-///     assert!(asserted_bool == true);
-/// ```
-///
-/// ```
-///     use inflector::cases::tablecase::is_table_case;
-///     let mock_string: &str = "foo-bar-string-that-is-really-really-long";
-///     let asserted_bool: bool = is_table_case(mock_string);
-///     assert!(asserted_bool == false);
-/// ```
-///
-/// ```
-///     use inflector::cases::tablecase::is_table_case;
-///     let mock_string: &str = "FooBarIsAReallyReallyLongString";
-///     let asserted_bool: bool = is_table_case(mock_string);
-///     assert!(asserted_bool == false);
-/// ```
-///
-/// ```
-///     use inflector::cases::tablecase::is_table_case;
-///     let mock_string: &str = "fooBarIsAReallyReallyLongString";
-///     let asserted_bool: bool = is_table_case(mock_string);
-///     assert!(asserted_bool == false);
-/// ```
-///
-/// ```
-///     use inflector::cases::tablecase::is_table_case;
-///     let mock_string: &str = "FOO_BAR_STRING_THAT_IS_REALLY_REALLY_LONG";
-///     let asserted_bool: bool = is_table_case(mock_string);
-///     assert!(asserted_bool == false);
-/// ```
-///
-/// ```
-///     use inflector::cases::tablecase::is_table_case;
-///     let mock_string: &str = "foo_bar_string_that_is_really_really_long";
-///     let asserted_bool: bool = is_table_case(mock_string);
-///     assert!(asserted_bool == false);
-/// ```
-///
-/// ```
-///     use inflector::cases::tablecase::is_table_case;
-///     let mock_string: &str = "Foo bar string that is really really long";
-///     let asserted_bool: bool = is_table_case(mock_string);
-///     assert!(asserted_bool == false);
-/// ```
-///
-/// ```
-///     use inflector::cases::tablecase::is_table_case;
-///     let mock_string: &str = "Foo Bar Is A Really Really Long String";
-///     let asserted_bool: bool = is_table_case(mock_string);
-///     assert!(asserted_bool == false);
-/// ```
-pub fn is_table_case(test_string: &str) -> bool {
-     to_table_case(&test_string.clone()) == test_string
-}
-
-#[cfg(all(feature = "unstable", test))]
-#[cfg(feature = "heavyweight")]
-mod benchmarks {
-    extern crate test;
-    use self::test::Bencher;
-
-    #[bench]
-    fn bench_table_case(b: &mut Bencher) {
-        b.iter(|| super::to_table_case("Foo bar"));
-    }
-
-    #[bench]
-    fn bench_is_table_case(b: &mut Bencher) {
-        b.iter(|| super::is_table_case("Foo bar"));
-    }
-}
-
-#[cfg(test)]
-#[cfg(feature = "heavyweight")]
-mod tests {
-    use ::to_table_case;
-    use ::is_table_case;
-
-    #[test]
-    fn from_camel_case() {
-        let convertable_string: String = "fooBar".to_owned();
-        let expected: String = "foo_bars".to_owned();
-        assert_eq!(to_table_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_pascal_case() {
-        let convertable_string: String = "FooBar".to_owned();
-        let expected: String = "foo_bars".to_owned();
-        assert_eq!(to_table_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_kebab_case() {
-        let convertable_string: String = "foo-bar".to_owned();
-        let expected: String = "foo_bars".to_owned();
-        assert_eq!(to_table_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_sentence_case() {
-        let convertable_string: String = "Foo bar".to_owned();
-        let expected: String = "foo_bars".to_owned();
-        assert_eq!(to_table_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_title_case() {
-        let convertable_string: String = "Foo Bar".to_owned();
-        let expected: String = "foo_bars".to_owned();
-        assert_eq!(to_table_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_train_case() {
-        let convertable_string: String = "Foo-Bar".to_owned();
-        let expected: String = "foo_bars".to_owned();
-        assert_eq!(to_table_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_screaming_snake_case() {
-        let convertable_string: String = "FOO_BAR".to_owned();
-        let expected: String = "foo_bars".to_owned();
-        assert_eq!(to_table_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_snake_case() {
-        let convertable_string: String = "foo_bar".to_owned();
-        let expected: String = "foo_bars".to_owned();
-        assert_eq!(to_table_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_table_case() {
-        let convertable_string: String = "foo_bars".to_owned();
-        let expected: String = "foo_bars".to_owned();
-        assert_eq!(to_table_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn is_correct_from_camel_case() {
-        let convertable_string: String = "fooBar".to_owned();
-        assert_eq!(is_table_case(&convertable_string), false)
-    }
-
-    #[test]
-    fn is_correct_from_pascal_case() {
-        let convertable_string: String = "FooBar".to_owned();
-        assert_eq!(is_table_case(&convertable_string), false)
-    }
-
-    #[test]
-    fn is_correct_from_kebab_case() {
-        let convertable_string: String = "foo-bar".to_owned();
-        assert_eq!(is_table_case(&convertable_string), false)
-    }
-
-    #[test]
-    fn is_correct_from_sentence_case() {
-        let convertable_string: String = "Foo bar".to_owned();
-        assert_eq!(is_table_case(&convertable_string), false)
-    }
-
-    #[test]
-    fn is_correct_from_title_case() {
-        let convertable_string: String = "Foo Bar".to_owned();
-        assert_eq!(is_table_case(&convertable_string), false)
-    }
-
-    #[test]
-    fn is_correct_from_train_case() {
-        let convertable_string: String = "Foo-Bar".to_owned();
-        assert_eq!(is_table_case(&convertable_string), false)
-    }
-
-    #[test]
-    fn is_correct_from_screaming_snake_case() {
-        let convertable_string: String = "FOO_BAR".to_owned();
-        assert_eq!(is_table_case(&convertable_string), false)
-    }
-
-    #[test]
-    fn is_correct_from_snake_case() {
-        let convertable_string: String = "foo_bar".to_owned();
-        assert_eq!(is_table_case(&convertable_string), false)
-    }
-
-    #[test]
-    fn is_correct_from_table_case() {
-        let convertable_string: String = "foo_bars".to_owned();
-        assert_eq!(is_table_case(&convertable_string), true)
-    }
-}
diff --git a/third_party/rust/Inflector/src/cases/titlecase/mod.rs b/third_party/rust/Inflector/src/cases/titlecase/mod.rs
deleted file mode 100644
index eb0de25744..0000000000
--- a/third_party/rust/Inflector/src/cases/titlecase/mod.rs
+++ /dev/null
@@ -1,308 +0,0 @@
-#![deny(warnings)]
-use cases::case::*;
-/// Converts a `&str` to `Title Case` `String`
-///
-/// ```
-///     use inflector::cases::titlecase::to_title_case;
-///     let mock_string: &str = "Foo bar";
-///     let expected_string: String = "Foo Bar".to_string();
-///     let asserted_string: String = to_title_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::cases::titlecase::to_title_case;
-///     let mock_string: &str = "FooBar";
-///     let expected_string: String = "Foo Bar".to_string();
-///     let asserted_string: String = to_title_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::cases::titlecase::to_title_case;
-///     let mock_string: &str = "fooBar";
-///     let expected_string: String = "Foo Bar".to_string();
-///     let asserted_string: String = to_title_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::cases::titlecase::to_title_case;
-///     let mock_string: &str = "FOO_BAR";
-///     let expected_string: String = "Foo Bar".to_string();
-///     let asserted_string: String = to_title_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::cases::titlecase::to_title_case;
-///     let mock_string: &str = "foo_bar";
-///     let expected_string: String = "Foo Bar".to_string();
-///     let asserted_string: String = to_title_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::cases::titlecase::to_title_case;
-///     let mock_string: &str = "foo-bar";
-///     let expected_string: String = "Foo Bar".to_string();
-///     let asserted_string: String = to_title_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-pub fn to_title_case(non_title_case_string: &str) -> String {
-    let options = CamelOptions {
-        new_word: true,
-        last_char: ' ',
-        first_word: true,
-        injectable_char: ' ',
-        has_seperator: true,
-        inverted: false,
-    };
-    to_case_camel_like(non_title_case_string, options)
-}
-
-/// Determines if a `&str` is `Title Case`
-///
-/// ```
-///     use inflector::cases::titlecase::is_title_case;
-///     let mock_string: &str = "foo-bar-string-that-is-really-really-long";
-///     let asserted_bool: bool = is_title_case(mock_string);
-///     assert!(asserted_bool == false);
-///
-/// ```
-/// ```
-///     use inflector::cases::titlecase::is_title_case;
-///     let mock_string: &str = "FooBarIsAReallyReallyLongString";
-///     let asserted_bool: bool = is_title_case(mock_string);
-///     assert!(asserted_bool == false);
-///
-/// ```
-/// ```
-///     use inflector::cases::titlecase::is_title_case;
-///     let mock_string: &str = "fooBarIsAReallyReallyLongString";
-///     let asserted_bool: bool = is_title_case(mock_string);
-///     assert!(asserted_bool == false);
-///
-/// ```
-/// ```
-///     use inflector::cases::titlecase::is_title_case;
-///     let mock_string: &str = "FOO_BAR_STRING_THAT_IS_REALLY_REALLY_LONG";
-///     let asserted_bool: bool = is_title_case(mock_string);
-///     assert!(asserted_bool == false);
-///
-/// ```
-/// ```
-///     use inflector::cases::titlecase::is_title_case;
-///     let mock_string: &str = "foo_bar_string_that_is_really_really_long";
-///     let asserted_bool: bool = is_title_case(mock_string);
-///     assert!(asserted_bool == false);
-///
-/// ```
-/// ```
-///     use inflector::cases::titlecase::is_title_case;
-///     let mock_string: &str = "Foo bar string that is really really long";
-///     let asserted_bool: bool = is_title_case(mock_string);
-///     assert!(asserted_bool == false);
-///
-/// ```
-/// ```
-///     use inflector::cases::titlecase::is_title_case;
-///     let mock_string: &str = "foo";
-///     let asserted_bool: bool = is_title_case(mock_string);
-///     assert!(asserted_bool == false);
-///
-/// ```
-/// ```
-///     use inflector::cases::titlecase::is_title_case;
-///     let mock_string: &str = "Foo Bar String That Is Really Really Long";
-///     let asserted_bool: bool = is_title_case(mock_string);
-///     assert!(asserted_bool == true);
-///
-/// ```
-pub fn is_title_case(test_string: &str) -> bool {
-    test_string == to_title_case(test_string.clone())
-}
-
-#[cfg(all(feature = "unstable", test))]
-mod benchmarks {
-    extern crate test;
-    use self::test::Bencher;
-
-    #[bench]
-    fn bench_title(b: &mut Bencher) {
-        b.iter(|| super::to_title_case("Foo BAR"));
-    }
-
-    #[bench]
-    fn bench_is_title(b: &mut Bencher) {
-        b.iter(|| super::is_title_case("Foo bar"));
-    }
-
-    #[bench]
-    fn bench_title_from_snake(b: &mut Bencher) {
-        b.iter(|| super::to_title_case("foo_bar"));
-    }
-
-}
-
-
-#[cfg(test)]
-mod tests {
-    use ::to_title_case;
-    use ::is_title_case;
-
-    #[test]
-    fn from_camel_case() {
-        let convertable_string: String = "fooBar".to_owned();
-        let expected: String = "Foo Bar".to_owned();
-        assert_eq!(to_title_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_pascal_case() {
-        let convertable_string: String = "FooBar".to_owned();
-        let expected: String = "Foo Bar".to_owned();
-        assert_eq!(to_title_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_kebab_case() {
-        let convertable_string: String = "foo-bar".to_owned();
-        let expected: String = "Foo Bar".to_owned();
-        assert_eq!(to_title_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_sentence_case() {
-        let convertable_string: String = "Foo bar".to_owned();
-        let expected: String = "Foo Bar".to_owned();
-        assert_eq!(to_title_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_title_case() {
-        let convertable_string: String = "Foo Bar".to_owned();
-        let expected: String = "Foo Bar".to_owned();
-        assert_eq!(to_title_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_train_case() {
-        let convertable_string: String = "Foo-Bar".to_owned();
-        let expected: String = "Foo Bar".to_owned();
-        assert_eq!(to_title_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_screaming_snake_case() {
-        let convertable_string: String = "FOO_BAR".to_owned();
-        let expected: String = "Foo Bar".to_owned();
-        assert_eq!(to_title_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_snake_case() {
-        let convertable_string: String = "foo_bar".to_owned();
-        let expected: String = "Foo Bar".to_owned();
-        assert_eq!(to_title_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_case_with_loads_of_space() {
-        let convertable_string: String = "foo           bar".to_owned();
-        let expected: String = "Foo Bar".to_owned();
-        assert_eq!(to_title_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn a_name_with_a_dot() {
-        let convertable_string: String = "Robert C. Martin".to_owned();
-        let expected: String = "Robert C Martin".to_owned();
-        assert_eq!(to_title_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn random_text_with_bad_chars() {
-        let convertable_string: String = "Random text with *(bad) chars".to_owned();
-        let expected: String = "Random Text With Bad Chars".to_owned();
-        assert_eq!(to_title_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn trailing_bad_chars() {
-        let convertable_string: String = "trailing bad_chars*(()())".to_owned();
-        let expected: String = "Trailing Bad Chars".to_owned();
-        assert_eq!(to_title_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn leading_bad_chars() {
-        let convertable_string: String = "-!#$%leading bad chars".to_owned();
-        let expected: String = "Leading Bad Chars".to_owned();
-        assert_eq!(to_title_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn wrapped_in_bad_chars() {
-        let convertable_string: String = "-!#$%wrapped in bad chars&*^*&(&*^&(<><?>><?><>))".to_owned();
-        let expected: String = "Wrapped In Bad Chars".to_owned();
-        assert_eq!(to_title_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn has_a_sign() {
-        let convertable_string: String = "has a + sign".to_owned();
-        let expected: String = "Has A Sign".to_owned();
-        assert_eq!(to_title_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn is_correct_from_camel_case() {
-        let convertable_string: String = "fooBar".to_owned();
-        assert_eq!(is_title_case(&convertable_string), false)
-    }
-
-    #[test]
-    fn is_correct_from_pascal_case() {
-        let convertable_string: String = "FooBar".to_owned();
-        assert_eq!(is_title_case(&convertable_string), false)
-    }
-
-    #[test]
-    fn is_correct_from_kebab_case() {
-        let convertable_string: String = "foo-bar".to_owned();
-        assert_eq!(is_title_case(&convertable_string), false)
-    }
-
-    #[test]
-    fn is_correct_from_sentence_case() {
-        let convertable_string: String = "Foo bar".to_owned();
-        assert_eq!(is_title_case(&convertable_string), false)
-    }
-
-    #[test]
-    fn is_correct_from_title_case() {
-        let convertable_string: String = "Foo Bar".to_owned();
-        assert_eq!(is_title_case(&convertable_string), true)
-    }
-
-    #[test]
-    fn is_correct_from_train_case() {
-        let convertable_string: String = "Foo-Bar".to_owned();
-        assert_eq!(is_title_case(&convertable_string), false)
-    }
-
-    #[test]
-    fn is_correct_from_screaming_snake_case() {
-        let convertable_string: String = "FOO_BAR".to_owned();
-        assert_eq!(is_title_case(&convertable_string), false)
-    }
-
-    #[test]
-    fn is_correct_from_snake_case() {
-        let convertable_string: String = "foo_bar".to_owned();
-        assert_eq!(is_title_case(&convertable_string), false)
-    }
-}
-
diff --git a/third_party/rust/Inflector/src/cases/traincase/mod.rs b/third_party/rust/Inflector/src/cases/traincase/mod.rs
deleted file mode 100644
index cb2e882818..0000000000
--- a/third_party/rust/Inflector/src/cases/traincase/mod.rs
+++ /dev/null
@@ -1,320 +0,0 @@
-#![deny(warnings)]
-use cases::case::*;
-/// Determines if a `&str` is `Train-Case`
-///
-/// ```
-///     use inflector::cases::traincase::is_train_case;
-///     let mock_string: &str = "Foo-Bar-String-That-Is-Really-Really-Long";
-///     let asserted_bool: bool = is_train_case(mock_string);
-///     assert!(asserted_bool == true);
-///
-/// ```
-///
-/// ```
-///     use inflector::cases::traincase::is_train_case;
-///     let mock_string: &str = "foo-bar-string-that-is-really-really-long";
-///     let asserted_bool: bool = is_train_case(mock_string);
-///     assert!(asserted_bool == false);
-///
-/// ```
-///
-/// ```
-///     use inflector::cases::traincase::is_train_case;
-///     let mock_string: &str = "FooBarIsAReallyReallyLongString";
-///     let asserted_bool: bool = is_train_case(mock_string);
-///     assert!(asserted_bool == false);
-///
-/// ```
-///
-/// ```
-///     use inflector::cases::traincase::is_train_case;
-///     let mock_string: &str = "fooBarIsAReallyReallyLongString";
-///     let asserted_bool: bool = is_train_case(mock_string);
-///     assert!(asserted_bool == false);
-///
-/// ```
-///
-/// ```
-///     use inflector::cases::traincase::is_train_case;
-///     let mock_string: &str = "foo_bar_string_that_is_really_really_long";
-///     let asserted_bool: bool = is_train_case(mock_string);
-///     assert!(asserted_bool == false);
-///
-/// ```
-///
-/// ```
-///     use inflector::cases::traincase::is_train_case;
-///     let mock_string: &str = "Foo bar string that is really really long";
-///     let asserted_bool: bool = is_train_case(mock_string);
-///     assert!(asserted_bool == false);
-///
-/// ```
-///
-/// ```
-///     use inflector::cases::traincase::is_train_case;
-///     let mock_string: &str = "Foo Bar Is A Really Really Long String";
-///     let asserted_bool: bool = is_train_case(mock_string);
-///     assert!(asserted_bool == false);
-///
-/// ```
-pub fn is_train_case(test_string: &str) -> bool {
-    test_string == to_train_case(test_string.clone())
-}
-
-
-/// Converts a `&str` to `Train-Case` `String`
-///
-/// ```
-///     use inflector::cases::traincase::to_train_case;
-///     let mock_string: &str = "foo-bar";
-///     let expected_string: String = "Foo-Bar".to_string();
-///     let asserted_string: String = to_train_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-///
-/// ```
-///     use inflector::cases::traincase::to_train_case;
-///     let mock_string: &str = "FOO_BAR";
-///     let expected_string: String = "Foo-Bar".to_string();
-///     let asserted_string: String = to_train_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-///
-/// ```
-///     use inflector::cases::traincase::to_train_case;
-///     let mock_string: &str = "foo_bar";
-///     let expected_string: String = "Foo-Bar".to_string();
-///     let asserted_string: String = to_train_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-///
-/// ```
-///     use inflector::cases::traincase::to_train_case;
-///     let mock_string: &str = "Foo Bar";
-///     let expected_string: String = "Foo-Bar".to_string();
-///     let asserted_string: String = to_train_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-///
-/// ```
-///     use inflector::cases::traincase::to_train_case;
-///     let mock_string: &str = "Foo bar";
-///     let expected_string: String = "Foo-Bar".to_string();
-///     let asserted_string: String = to_train_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-///
-/// ```
-///     use inflector::cases::traincase::to_train_case;
-///     let mock_string: &str = "FooBar";
-///     let expected_string: String = "Foo-Bar".to_string();
-///     let asserted_string: String = to_train_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-///
-/// ```
-///     use inflector::cases::traincase::to_train_case;
-///     let mock_string: &str = "fooBar";
-///     let expected_string: String = "Foo-Bar".to_string();
-///     let asserted_string: String = to_train_case(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-pub fn to_train_case(non_train_case_string: &str) -> String {
-    let options = CamelOptions {
-        new_word: true,
-        last_char: ' ',
-        first_word: true,
-        injectable_char: '-',
-        has_seperator: true,
-        inverted: false,
-    };
-    to_case_camel_like(non_train_case_string, options)
-}
-
-#[cfg(all(feature = "unstable", test))]
-mod benchmarks {
-    extern crate test;
-    use self::test::Bencher;
-
-    #[bench]
-    fn bench_train(b: &mut Bencher) {
-        b.iter(|| super::to_train_case("Foo bar"));
-    }
-
-    #[bench]
-    fn bench_is_train(b: &mut Bencher) {
-        b.iter(|| super::is_train_case("Foo bar"));
-    }
-
-    #[bench]
-    fn bench_train_from_snake(b: &mut Bencher) {
-        b.iter(|| super::to_train_case("test_test_test"));
-    }
-
-}
-
-#[cfg(test)]
-mod tests {
-    use ::to_train_case;
-    use ::is_train_case;
-
-    #[test]
-    fn from_camel_case() {
-        let convertable_string: String = "fooBar".to_owned();
-        let expected: String = "Foo-Bar".to_owned();
-        assert_eq!(to_train_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_pascal_case() {
-        let convertable_string: String = "FooBar".to_owned();
-        let expected: String = "Foo-Bar".to_owned();
-        assert_eq!(to_train_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_kebab_case() {
-        let convertable_string: String = "foo-bar".to_owned();
-        let expected: String = "Foo-Bar".to_owned();
-        assert_eq!(to_train_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_sentence_case() {
-        let convertable_string: String = "Foo bar".to_owned();
-        let expected: String = "Foo-Bar".to_owned();
-        assert_eq!(to_train_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_title_case() {
-        let convertable_string: String = "Foo Bar".to_owned();
-        let expected: String = "Foo-Bar".to_owned();
-        assert_eq!(to_train_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_train_case() {
-        let convertable_string: String = "Foo-Bar".to_owned();
-        let expected: String = "Foo-Bar".to_owned();
-        assert_eq!(to_train_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_screaming_snake_case() {
-        let convertable_string: String = "FOO_BAR".to_owned();
-        let expected: String = "Foo-Bar".to_owned();
-        assert_eq!(to_train_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_snake_case() {
-        let convertable_string: String = "foo_bar".to_owned();
-        let expected: String = "Foo-Bar".to_owned();
-        assert_eq!(to_train_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn from_case_with_loads_of_space() {
-        let convertable_string: String = "foo           bar".to_owned();
-        let expected: String = "Foo-Bar".to_owned();
-        assert_eq!(to_train_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn a_name_with_a_dot() {
-        let convertable_string: String = "Robert C. Martin".to_owned();
-        let expected: String = "Robert-C-Martin".to_owned();
-        assert_eq!(to_train_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn random_text_with_bad_chars() {
-        let convertable_string: String = "Random text with *(bad) chars".to_owned();
-        let expected: String = "Random-Text-With-Bad-Chars".to_owned();
-        assert_eq!(to_train_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn trailing_bad_chars() {
-        let convertable_string: String = "trailing bad_chars*(()())".to_owned();
-        let expected: String = "Trailing-Bad-Chars".to_owned();
-        assert_eq!(to_train_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn leading_bad_chars() {
-        let convertable_string: String = "-!#$%leading bad chars".to_owned();
-        let expected: String = "Leading-Bad-Chars".to_owned();
-        assert_eq!(to_train_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn wrapped_in_bad_chars() {
-        let convertable_string: String = "-!#$%wrapped in bad chars&*^*&(&*^&(<><?>><?><>))".to_owned();
-        let expected: String = "Wrapped-In-Bad-Chars".to_owned();
-        assert_eq!(to_train_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn has_a_sign() {
-        let convertable_string: String = "has a + sign".to_owned();
-        let expected: String = "Has-A-Sign".to_owned();
-        assert_eq!(to_train_case(&convertable_string), expected)
-    }
-
-    #[test]
-    fn is_correct_from_camel_case() {
-        let convertable_string: String = "fooBar".to_owned();
-        assert_eq!(is_train_case(&convertable_string), false)
-    }
-
-    #[test]
-    fn is_correct_from_pascal_case() {
-        let convertable_string: String = "FooBar".to_owned();
-        assert_eq!(is_train_case(&convertable_string), false)
-    }
-
-    #[test]
-    fn is_correct_from_kebab_case() {
-        let convertable_string: String = "foo-bar".to_owned();
-        assert_eq!(is_train_case(&convertable_string), false)
-    }
-
-    #[test]
-    fn is_correct_from_sentence_case() {
-        let convertable_string: String = "Foo bar".to_owned();
-        assert_eq!(is_train_case(&convertable_string), false)
-    }
-
-    #[test]
-    fn is_correct_from_title_case() {
-        let convertable_string: String = "Foo Bar".to_owned();
-        assert_eq!(is_train_case(&convertable_string), false)
-    }
-
-    #[test]
-    fn is_correct_from_train_case() {
-        let convertable_string: String = "Foo-Bar".to_owned();
-        assert_eq!(is_train_case(&convertable_string), true)
-    }
-
-    #[test]
-    fn is_correct_from_screaming_snake_case() {
-        let convertable_string: String = "FOO_BAR".to_owned();
-        assert_eq!(is_train_case(&convertable_string), false)
-    }
-
-    #[test]
-    fn is_correct_from_snake_case() {
-        let convertable_string: String = "foo_bar".to_owned();
-        assert_eq!(is_train_case(&convertable_string), false)
-    }
-}
diff --git a/third_party/rust/Inflector/src/lib.rs b/third_party/rust/Inflector/src/lib.rs
deleted file mode 100644
index f52ea29f40..0000000000
--- a/third_party/rust/Inflector/src/lib.rs
+++ /dev/null
@@ -1,332 +0,0 @@
-#![deny(warnings, unused_variables, missing_docs, unsafe_code, unused_extern_crates)]
-#![cfg_attr(feature = "unstable", feature(test))]
-
-//! Adds String based inflections for Rust. Snake, kebab, train, camel,
-//! sentence, class, and title cases as well as ordinalize,
-//! deordinalize, demodulize, deconstantize, and foreign key are supported as
-//! both traits and pure functions acting on String types.
-//! ```rust
-//! use inflector::Inflector;
-//! let camel_case_string: String = "some_string".to_camel_case();
-//! let is_camel_cased: bool= camel_case_string.is_camel_case();
-//! assert!(is_camel_cased == true);
-//! ```
-
-#[cfg(feature = "heavyweight")]
-extern crate regex;
-
-#[cfg(feature = "heavyweight")]
-#[macro_use] extern crate lazy_static;
-
-/// Provides case inflections
-/// - Camel case
-/// - Class case
-/// - Kebab case
-/// - Train case
-/// - Screaming snake case
-/// - Table case
-/// - Sentence case
-/// - Snake case
-/// - Pascal case
-pub mod cases;
-/// Provides number inflections
-/// - Ordinalize
-/// - Deordinalize
-pub mod numbers;
-/// Provides suffix inflections
-/// - Foreign key
-pub mod suffix;
-/// Provides string inflections
-/// - Deconstantize
-/// - Demodulize
-/// - Pluralize
-/// - Singularize
-#[cfg(feature = "heavyweight")]
-pub mod string;
-
-
-#[cfg(feature = "heavyweight")]
-use cases::classcase::to_class_case;
-#[cfg(feature = "heavyweight")]
-use cases::classcase::is_class_case;
-
-use cases::camelcase::to_camel_case;
-use cases::camelcase::is_camel_case;
-
-use cases::pascalcase::to_pascal_case;
-use cases::pascalcase::is_pascal_case;
-
-use cases::snakecase::to_snake_case;
-use cases::snakecase::is_snake_case;
-
-use cases::screamingsnakecase::to_screaming_snake_case;
-use cases::screamingsnakecase::is_screaming_snake_case;
-
-use cases::kebabcase::to_kebab_case;
-use cases::kebabcase::is_kebab_case;
-
-use cases::traincase::to_train_case;
-use cases::traincase::is_train_case;
-
-use cases::sentencecase::to_sentence_case;
-use cases::sentencecase::is_sentence_case;
-
-use cases::titlecase::to_title_case;
-use cases::titlecase::is_title_case;
-
-#[cfg(feature = "heavyweight")]
-use cases::tablecase::to_table_case;
-#[cfg(feature = "heavyweight")]
-use cases::tablecase::is_table_case;
-
-use numbers::ordinalize::ordinalize;
-use numbers::deordinalize::deordinalize;
-
-use suffix::foreignkey::to_foreign_key;
-use suffix::foreignkey::is_foreign_key;
-
-#[cfg(feature = "heavyweight")]
-use string::demodulize::demodulize;
-#[cfg(feature = "heavyweight")]
-use string::deconstantize::deconstantize;
-
-#[cfg(feature = "heavyweight")]
-use string::pluralize::to_plural;
-#[cfg(feature = "heavyweight")]
-use string::singularize::to_singular;
-
-#[allow(missing_docs)]
-pub trait Inflector {
-
-    fn to_camel_case(&self) -> String;
-    fn is_camel_case(&self) -> bool;
-
-    fn to_pascal_case(&self) -> String;
-    fn is_pascal_case(&self) -> bool;
-
-    fn to_snake_case(&self) -> String;
-    fn is_snake_case(&self) -> bool;
-
-    fn to_screaming_snake_case(&self) -> String;
-    fn is_screaming_snake_case(&self) -> bool;
-
-    fn to_kebab_case(&self) -> String;
-    fn is_kebab_case(&self) -> bool;
-
-    fn to_train_case(&self) -> String;
-    fn is_train_case(&self) -> bool;
-
-    fn to_sentence_case(&self) -> String;
-    fn is_sentence_case(&self) -> bool;
-
-    fn to_title_case(&self) -> String;
-    fn is_title_case(&self) -> bool;
-
-    fn ordinalize(&self) -> String;
-    fn deordinalize(&self) -> String;
-
-    fn to_foreign_key(&self) -> String;
-    fn is_foreign_key(&self) -> bool;
-
-    #[cfg(feature = "heavyweight")]
-    fn demodulize(&self) -> String;
-    #[cfg(feature = "heavyweight")]
-    fn deconstantize(&self) -> String;
-
-    #[cfg(feature = "heavyweight")]
-    fn to_class_case(&self) -> String;
-    #[cfg(feature = "heavyweight")]
-    fn is_class_case(&self) -> bool;
-
-    #[cfg(feature = "heavyweight")]
-    fn to_table_case(&self) -> String;
-    #[cfg(feature = "heavyweight")]
-    fn is_table_case(&self) -> bool;
-    #[cfg(feature = "heavyweight")]
-    fn to_plural(&self) -> String;
-    #[cfg(feature = "heavyweight")]
-    fn to_singular(&self) -> String;
-}
-
-
-#[allow(missing_docs)]
-pub trait InflectorNumbers {
-    fn ordinalize(&self) -> String;
-}
-
-
-macro_rules! define_implementations {
-    ( $slf:ident; $($imp_trait:ident => $typ:ident), *) => {
-        $(
-            #[inline]
-            fn $imp_trait(&$slf) -> $typ {
-                $imp_trait($slf)
-            }
-        )*
-    }
-}
-
-macro_rules! define_number_implementations {
-    ( $slf:ident; $($imp_trait:ident => $typ:ident), *) => {
-        $(
-            #[inline]
-            fn $imp_trait(&$slf) -> $typ {
-                $imp_trait(&$slf.to_string())
-            }
-        )*
-    }
-}
-
-macro_rules! define_gated_implementations {
-    ( $slf:ident; $($imp_trait:ident => $typ:ident), *) => {
-        $(
-            #[inline]
-            #[cfg(feature = "heavyweight")]
-            fn $imp_trait(&$slf) -> $typ {
-                $imp_trait($slf)
-            }
-        )*
-    }
-}
-
-macro_rules! implement_string_for {
-    ( $trt:ident; $($typ:ident), *) => {
-        $(
-            impl $trt for $typ {
-                define_implementations![self;
-                    to_camel_case => String,
-                    is_camel_case => bool,
-                    to_pascal_case => String,
-                    is_pascal_case => bool,
-                    to_screaming_snake_case => String,
-                    is_screaming_snake_case => bool,
-                    to_snake_case => String,
-                    is_snake_case => bool,
-                    to_kebab_case => String,
-                    is_kebab_case => bool,
-                    to_train_case => String,
-                    is_train_case => bool,
-                    to_sentence_case => String,
-                    is_sentence_case => bool,
-                    to_title_case => String,
-                    is_title_case => bool,
-                    to_foreign_key => String,
-                    is_foreign_key => bool,
-                    ordinalize => String,
-                    deordinalize => String
-                ];
-                define_gated_implementations![self;
-                    to_class_case => String,
-                    is_class_case => bool,
-                    to_table_case => String,
-                    is_table_case => bool,
-                    to_plural => String,
-                    to_singular => String,
-                    demodulize => String,
-                    deconstantize => String
-                ];
-            }
-        )*
-    }
-}
-
-macro_rules! implement_number_for {
-    ( $trt:ident; $($typ:ident), *) => {
-        $(
-            impl $trt for $typ {
-                define_number_implementations![self;
-                    ordinalize => String
-                ];
-            }
-        )*
-    }
-}
-
-implement_string_for![
-    Inflector;
-    String, str
-];
-
-implement_number_for![
-    InflectorNumbers;
-    i8, i16, i32, i64, u8, u16, u32, u64, isize, usize, f32, f64
-];
-
-#[cfg(all(feature = "unstable", test))]
-mod benchmarks {
-    extern crate test;
-    use self::test::Bencher;
-    use ::Inflector;
-
-    macro_rules! benchmarks {
-        ( $($test_name:ident => $imp_trait:ident => $to_cast:expr), *) => {
-            $(
-                #[bench]
-                fn $test_name(b: &mut Bencher) {
-                    b.iter(|| {
-                        $to_cast.$imp_trait()
-                    });
-                }
-            )*
-        }
-    }
-
-    benchmarks![
-        benchmark_str_to_camel => to_camel_case => "foo_bar",
-        benchmark_str_is_camel => is_camel_case => "fooBar",
-        benchmark_str_to_screaming_snake => to_screaming_snake_case => "fooBar",
-        benchmark_str_is_screaming_snake => is_screaming_snake_case => "FOO_BAR",
-        benchmark_str_to_snake => to_snake_case => "fooBar",
-        benchmark_str_is_snake => is_snake_case => "foo_bar",
-        benchmark_str_to_kebab => to_kebab_case => "fooBar",
-        benchmark_str_is_kebab => is_kebab_case => "foo-bar",
-        benchmark_str_to_train => to_train_case => "fooBar",
-        benchmark_str_is_train => is_train_case => "Foo-Bar",
-        benchmark_str_to_sentence => to_sentence_case => "fooBar",
-        benchmark_str_is_sentence => is_sentence_case => "Foo bar",
-        benchmark_str_to_title => to_title_case => "fooBar",
-        benchmark_str_is_title => is_title_case => "Foo Bar",
-        benchmark_str_ordinalize  => ordinalize => "1",
-        benchmark_str_deordinalize  => deordinalize => "1st",
-        benchmark_str_to_foreign_key => to_foreign_key => "Foo::Bar",
-        benchmark_str_is_foreign_key => is_foreign_key => "bar_id",
-        benchmark_string_to_camel => to_camel_case => "foo_bar".to_string(),
-        benchmark_string_is_camel => is_camel_case => "fooBar".to_string(),
-        benchmark_string_to_screaming_snake => to_screaming_snake_case => "fooBar".to_string(),
-        benchmark_string_is_screaming_snake => is_screaming_snake_case => "FOO_BAR".to_string(),
-        benchmark_string_to_snake => to_snake_case => "fooBar".to_string(),
-        benchmark_string_is_snake => is_snake_case => "foo_bar".to_string(),
-        benchmark_string_to_kebab => to_kebab_case => "fooBar".to_string(),
-        benchmark_string_is_kebab => is_kebab_case => "foo-bar".to_string(),
-        benchmark_string_to_train => to_train_case => "fooBar".to_string(),
-        benchmark_string_is_train => is_train_case => "Foo-Bar".to_string(),
-        benchmark_string_to_sentence => to_sentence_case => "fooBar".to_string(),
-        benchmark_string_is_sentence => is_sentence_case => "Foo bar".to_string(),
-        benchmark_string_to_title => to_title_case => "fooBar".to_string(),
-        benchmark_string_is_title => is_title_case => "Foo Bar".to_string(),
-        benchmark_string_ordinalize  => ordinalize => "1".to_string(),
-        benchmark_string_deordinalize  => deordinalize => "1st".to_string(),
-        benchmark_string_to_foreign_key => to_foreign_key => "Foo::Bar".to_string(),
-        benchmark_string_is_foreign_key => is_foreign_key => "bar_id".to_string()
-    ];
-
-    #[cfg(feature = "heavyweight")]
-    benchmarks![
-        benchmark_str_to_class => to_class_case => "foo",
-        benchmark_str_is_class => is_class_case => "Foo",
-        benchmark_str_to_table => to_table_case => "fooBar",
-        benchmark_str_is_table => is_table_case => "foo_bars",
-        benchmark_str_pluralize => to_plural => "crate",
-        benchmark_str_singular => to_singular => "crates",
-        benchmark_string_to_class => to_class_case => "foo".to_string(),
-        benchmark_string_is_class => is_class_case => "Foo".to_string(),
-        benchmark_string_to_table => to_table_case => "fooBar".to_string(),
-        benchmark_string_is_table => is_table_case => "foo_bars".to_string(),
-        benchmark_string_pluralize => to_plural => "crate".to_string(),
-        benchmark_string_singular => to_singular => "crates".to_string(),
-        benchmark_string_demodulize => demodulize => "Foo::Bar".to_string(),
-        benchmark_string_deconstantize => deconstantize => "Foo::Bar".to_string(),
-        benchmark_str_demodulize => demodulize => "Foo::Bar",
-        benchmark_str_deconstantize => deconstantize => "Foo::Bar"
-    ];
-}
diff --git a/third_party/rust/Inflector/src/numbers/deordinalize/mod.rs b/third_party/rust/Inflector/src/numbers/deordinalize/mod.rs
deleted file mode 100644
index f64cce1143..0000000000
--- a/third_party/rust/Inflector/src/numbers/deordinalize/mod.rs
+++ /dev/null
@@ -1,117 +0,0 @@
-/// Deorginalizes a `&str`
-///
-/// ```
-///     use inflector::numbers::deordinalize::deordinalize;
-///     let mock_string: &str = "0.1";
-///     let expected_string: String = "0.1".to_owned();
-///     let asserted_string: String = deordinalize(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::numbers::deordinalize::deordinalize;
-///     let mock_string: &str = "-1st";
-///     let expected_string: String = "-1".to_owned();
-///     let asserted_string: String = deordinalize(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::numbers::deordinalize::deordinalize;
-///     let mock_string: &str = "0th";
-///     let expected_string: String = "0".to_owned();
-///     let asserted_string: String = deordinalize(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::numbers::deordinalize::deordinalize;
-///     let mock_string: &str = "1st";
-///     let expected_string: String = "1".to_owned();
-///     let asserted_string: String = deordinalize(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::numbers::deordinalize::deordinalize;
-///     let mock_string: &str = "2nd";
-///     let expected_string: String = "2".to_owned();
-///     let asserted_string: String = deordinalize(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::numbers::deordinalize::deordinalize;
-///     let mock_string: &str = "3rd";
-///     let expected_string: String = "3".to_owned();
-///     let asserted_string: String = deordinalize(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::numbers::deordinalize::deordinalize;
-///     let mock_string: &str = "9th";
-///     let expected_string: String = "9".to_owned();
-///     let asserted_string: String = deordinalize(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::numbers::deordinalize::deordinalize;
-///     let mock_string: &str = "12th";
-///     let expected_string: String = "12".to_owned();
-///     let asserted_string: String = deordinalize(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::numbers::deordinalize::deordinalize;
-///     let mock_string: &str = "12000th";
-///     let expected_string: String = "12000".to_owned();
-///     let asserted_string: String = deordinalize(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::numbers::deordinalize::deordinalize;
-///     let mock_string: &str = "12001th";
-///     let expected_string: String = "12001".to_owned();
-///     let asserted_string: String = deordinalize(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::numbers::deordinalize::deordinalize;
-///     let mock_string: &str = "12002nd";
-///     let expected_string: String = "12002".to_owned();
-///     let asserted_string: String = deordinalize(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::numbers::deordinalize::deordinalize;
-///     let mock_string: &str = "12003rd";
-///     let expected_string: String = "12003".to_owned();
-///     let asserted_string: String = deordinalize(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::numbers::deordinalize::deordinalize;
-///     let mock_string: &str = "12004th";
-///     let expected_string: String = "12004".to_owned();
-///     let asserted_string: String = deordinalize(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-pub fn deordinalize(non_ordinalized_string: &str) -> String {
-    if non_ordinalized_string.contains('.') {
-        non_ordinalized_string.to_owned()
-    } else {
-        non_ordinalized_string.trim_end_matches("st")
-            .trim_end_matches("nd")
-            .trim_end_matches("rd")
-            .trim_end_matches("th")
-            .to_owned()
-    }
-}
diff --git a/third_party/rust/Inflector/src/numbers/mod.rs b/third_party/rust/Inflector/src/numbers/mod.rs
deleted file mode 100644
index f28704f52e..0000000000
--- a/third_party/rust/Inflector/src/numbers/mod.rs
+++ /dev/null
@@ -1,9 +0,0 @@
-#![deny(warnings)]
-/// Provides ordinalization of a string.
-///
-/// Example string "1" becomes "1st"
-pub mod ordinalize;
-/// Provides deordinalization of a string.
-///
-/// Example string "1st" becomes "1"
-pub mod deordinalize;
diff --git a/third_party/rust/Inflector/src/numbers/ordinalize/mod.rs b/third_party/rust/Inflector/src/numbers/ordinalize/mod.rs
deleted file mode 100644
index 82b0d2d834..0000000000
--- a/third_party/rust/Inflector/src/numbers/ordinalize/mod.rs
+++ /dev/null
@@ -1,147 +0,0 @@
-/// Orginalizes a `&str`
-///
-/// ```
-///     use inflector::numbers::ordinalize::ordinalize;
-///     let mock_string: &str = "a";
-///     let expected_string: String = "a".to_owned();
-///     let asserted_string: String = ordinalize(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::numbers::ordinalize::ordinalize;
-///     let mock_string: &str = "0.1";
-///     let expected_string: String = "0.1".to_owned();
-///     let asserted_string: String = ordinalize(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::numbers::ordinalize::ordinalize;
-///     let mock_string: &str = "-1";
-///     let expected_string: String = "-1st".to_owned();
-///     let asserted_string: String = ordinalize(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::numbers::ordinalize::ordinalize;
-///     let mock_string: &str = "0";
-///     let expected_string: String = "0th".to_owned();
-///     let asserted_string: String = ordinalize(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::numbers::ordinalize::ordinalize;
-///     let mock_string: &str = "1";
-///     let expected_string: String = "1st".to_owned();
-///     let asserted_string: String = ordinalize(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::numbers::ordinalize::ordinalize;
-///     let mock_string: &str = "2";
-///     let expected_string: String = "2nd".to_owned();
-///     let asserted_string: String = ordinalize(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::numbers::ordinalize::ordinalize;
-///     let mock_string: &str = "3";
-///     let expected_string: String = "3rd".to_owned();
-///     let asserted_string: String = ordinalize(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::numbers::ordinalize::ordinalize;
-///     let mock_string: &str = "9";
-///     let expected_string: String = "9th".to_owned();
-///     let asserted_string: String = ordinalize(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::numbers::ordinalize::ordinalize;
-///     let mock_string: &str = "12";
-///     let expected_string: String = "12th".to_owned();
-///     let asserted_string: String = ordinalize(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::numbers::ordinalize::ordinalize;
-///     let mock_string: &str = "12000";
-///     let expected_string: String = "12000th".to_owned();
-///     let asserted_string: String = ordinalize(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::numbers::ordinalize::ordinalize;
-///     let mock_string: &str = "12001";
-///     let expected_string: String = "12001st".to_owned();
-///     let asserted_string: String = ordinalize(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::numbers::ordinalize::ordinalize;
-///     let mock_string: &str = "12002";
-///     let expected_string: String = "12002nd".to_owned();
-///     let asserted_string: String = ordinalize(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::numbers::ordinalize::ordinalize;
-///     let mock_string: &str = "12003";
-///     let expected_string: String = "12003rd".to_owned();
-///     let asserted_string: String = ordinalize(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::numbers::ordinalize::ordinalize;
-///     let mock_string: &str = "12004";
-///     let expected_string: String = "12004th".to_owned();
-///     let asserted_string: String = ordinalize(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-pub fn ordinalize(non_ordinalized_string: &str) -> String {
-    let chars: Vec<char> = non_ordinalized_string.clone().chars().collect();
-    let last_number: char = chars[chars.len() - 1];
-    if is_ordinalizable(last_number) {
-        return non_ordinalized_string.to_owned();
-    }
-    if chars.len() > 1 {
-        if second_last_number_is_one(chars) {
-            return format!("{}{}", non_ordinalized_string, "th");
-        } else if string_contains_decimal(non_ordinalized_string.to_owned()) {
-            return non_ordinalized_string.to_owned();
-        }
-    }
-    match last_number {
-        '1' => format!("{}{}", non_ordinalized_string, "st"),
-        '2' => format!("{}{}", non_ordinalized_string, "nd"),
-        '3' => format!("{}{}", non_ordinalized_string, "rd"),
-        _ => format!("{}{}", non_ordinalized_string, "th"),
-    }
-}
-
-fn is_ordinalizable(last_number: char) -> bool {
-    !last_number.is_numeric()
-}
-
-fn second_last_number_is_one(chars: Vec<char>) -> bool {
-    let second_last_number: char = chars[chars.len() - 2];
-    second_last_number == '1'
-}
-
-fn string_contains_decimal(non_ordinalized_string: String) -> bool {
-    non_ordinalized_string.contains('.')
-}
diff --git a/third_party/rust/Inflector/src/string/constants/mod.rs b/third_party/rust/Inflector/src/string/constants/mod.rs
deleted file mode 100644
index 0ba4e429f9..0000000000
--- a/third_party/rust/Inflector/src/string/constants/mod.rs
+++ /dev/null
@@ -1,225 +0,0 @@
-pub const UNACCONTABLE_WORDS: [&'static str; 202] = ["accommodation",
-                                                     "adulthood",
-                                                     "advertising",
-                                                     "advice",
-                                                     "aggression",
-                                                     "aid",
-                                                     "air",
-                                                     "aircraft",
-                                                     "alcohol",
-                                                     "anger",
-                                                     "applause",
-                                                     "arithmetic",
-                                                     "assistance",
-                                                     "athletics",
-
-                                                     "bacon",
-                                                     "baggage",
-                                                     "beef",
-                                                     "biology",
-                                                     "blood",
-                                                     "botany",
-                                                     "bread",
-                                                     "butter",
-
-                                                     "carbon",
-                                                     "cardboard",
-                                                     "cash",
-                                                     "chalk",
-                                                     "chaos",
-                                                     "chess",
-                                                     "crossroads",
-                                                     "countryside",
-
-                                                     "dancing",
-                                                     "deer",
-                                                     "dignity",
-                                                     "dirt",
-                                                     "dust",
-
-                                                     "economics",
-                                                     "education",
-                                                     "electricity",
-                                                     "engineering",
-                                                     "enjoyment",
-                                                     "envy",
-                                                     "equipment",
-                                                     "ethics",
-                                                     "evidence",
-                                                     "evolution",
-
-                                                     "fame",
-                                                     "fiction",
-                                                     "flour",
-                                                     "flu",
-                                                     "food",
-                                                     "fuel",
-                                                     "fun",
-                                                     "furniture",
-
-                                                     "gallows",
-                                                     "garbage",
-                                                     "garlic",
-                                                     "genetics",
-                                                     "gold",
-                                                     "golf",
-                                                     "gossip",
-                                                     "grammar",
-                                                     "gratitude",
-                                                     "grief",
-                                                     "guilt",
-                                                     "gymnastics",
-
-                                                     "happiness",
-                                                     "hardware",
-                                                     "harm",
-                                                     "hate",
-                                                     "hatred",
-                                                     "health",
-                                                     "heat",
-                                                     "help",
-                                                     "homework",
-                                                     "honesty",
-                                                     "honey",
-                                                     "hospitality",
-                                                     "housework",
-                                                     "humour",
-                                                     "hunger",
-                                                     "hydrogen",
-
-                                                     "ice",
-                                                     "importance",
-                                                     "inflation",
-                                                     "information",
-                                                     "innocence",
-                                                     "iron",
-                                                     "irony",
-
-                                                     "jam",
-                                                     "jewelry",
-                                                     "judo",
-
-                                                     "karate",
-                                                     "knowledge",
-
-                                                     "lack",
-                                                     "laughter",
-                                                     "lava",
-                                                     "leather",
-                                                     "leisure",
-                                                     "lightning",
-                                                     "linguine",
-                                                     "linguini",
-                                                     "linguistics",
-                                                     "literature",
-                                                     "litter",
-                                                     "livestock",
-                                                     "logic",
-                                                     "loneliness",
-                                                     "luck",
-                                                     "luggage",
-
-                                                     "macaroni",
-                                                     "machinery",
-                                                     "magic",
-                                                     "management",
-                                                     "mankind",
-                                                     "marble",
-                                                     "mathematics",
-                                                     "mayonnaise",
-                                                     "measles",
-                                                     "methane",
-                                                     "milk",
-                                                     "money",
-                                                     "mud",
-                                                     "music",
-                                                     "mumps",
-
-                                                     "nature",
-                                                     "news",
-                                                     "nitrogen",
-                                                     "nonsense",
-                                                     "nurture",
-                                                     "nutrition",
-
-                                                     "obedience",
-                                                     "obesity",
-                                                     "oxygen",
-
-                                                     "pasta",
-                                                     "patience",
-                                                     "physics",
-                                                     "poetry",
-                                                     "pollution",
-                                                     "poverty",
-                                                     "pride",
-                                                     "psychology",
-                                                     "publicity",
-                                                     "punctuation",
-
-                                                     "quartz",
-
-                                                     "racism",
-                                                     "relaxation",
-                                                     "reliability",
-                                                     "research",
-                                                     "respect",
-                                                     "revenge",
-                                                     "rice",
-                                                     "rubbish",
-                                                     "rum",
-
-                                                     "safety",
-                                                     "scenery",
-                                                     "seafood",
-                                                     "seaside",
-                                                     "series",
-                                                     "shame",
-                                                     "sheep",
-                                                     "shopping",
-                                                     "sleep",
-                                                     "smoke",
-                                                     "smoking",
-                                                     "snow",
-                                                     "soap",
-                                                     "software",
-                                                     "soil",
-                                                     "spaghetti",
-                                                     "species",
-                                                     "steam",
-                                                     "stuff",
-                                                     "stupidity",
-                                                     "sunshine",
-                                                     "symmetry",
-
-                                                     "tennis",
-                                                     "thirst",
-                                                     "thunder",
-                                                     "timber",
-                                                     "traffic",
-                                                     "transportation",
-                                                     "trust",
-
-                                                     "underwear",
-                                                     "unemployment",
-                                                     "unity",
-
-                                                     "validity",
-                                                     "veal",
-                                                     "vegetation",
-                                                     "vegetarianism",
-                                                     "vengeance",
-                                                     "violence",
-                                                     "vitality",
-
-                                                     "warmth",
-                                                     "wealth",
-                                                     "weather",
-                                                     "welfare",
-                                                     "wheat",
-                                                     "wildlife",
-                                                     "wisdom",
-                                                     "yoga",
-
-                                                     "zinc",
-                                                     "zoology"];
diff --git a/third_party/rust/Inflector/src/string/deconstantize/mod.rs b/third_party/rust/Inflector/src/string/deconstantize/mod.rs
deleted file mode 100644
index 5b106e5655..0000000000
--- a/third_party/rust/Inflector/src/string/deconstantize/mod.rs
+++ /dev/null
@@ -1,50 +0,0 @@
-#[cfg(feature = "heavyweight")]
-use cases::classcase::to_class_case;
-
-#[cfg(feature = "heavyweight")]
-/// Deconstantizes a `&str`
-///
-/// ```
-///     use inflector::string::deconstantize::deconstantize;
-///     let mock_string: &str = "Bar";
-///     let expected_string: String = "".to_owned();
-///     let asserted_string: String = deconstantize(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::string::deconstantize::deconstantize;
-///     let mock_string: &str = "::Bar";
-///     let expected_string: String = "".to_owned();
-///     let asserted_string: String = deconstantize(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::string::deconstantize::deconstantize;
-///     let mock_string: &str = "Foo::Bar";
-///     let expected_string: String = "Foo".to_owned();
-///     let asserted_string: String = deconstantize(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::string::deconstantize::deconstantize;
-///     let mock_string: &str = "Test::Foo::Bar";
-///     let expected_string: String = "Foo".to_owned();
-///     let asserted_string: String = deconstantize(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-pub fn deconstantize(non_deconstantized_string: &str) -> String {
-    if non_deconstantized_string.contains("::") {
-        let split_string: Vec<&str> = non_deconstantized_string.split("::").collect();
-        if split_string.len() > 1 {
-            to_class_case(split_string[split_string.len() - 2])
-        } else {
-            "".to_owned()
-        }
-    } else {
-        "".to_owned()
-    }
-}
diff --git a/third_party/rust/Inflector/src/string/demodulize/mod.rs b/third_party/rust/Inflector/src/string/demodulize/mod.rs
deleted file mode 100644
index 5d4bd77168..0000000000
--- a/third_party/rust/Inflector/src/string/demodulize/mod.rs
+++ /dev/null
@@ -1,46 +0,0 @@
-#[cfg(feature = "heavyweight")]
-use cases::classcase::to_class_case;
-
-#[cfg(feature = "heavyweight")]
-/// Demodulize a `&str`
-///
-/// ```
-///     use inflector::string::demodulize::demodulize;
-///     let mock_string: &str = "Bar";
-///     let expected_string: String = "Bar".to_owned();
-///     let asserted_string: String = demodulize(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::string::demodulize::demodulize;
-///     let mock_string: &str = "::Bar";
-///     let expected_string: String = "Bar".to_owned();
-///     let asserted_string: String = demodulize(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::string::demodulize::demodulize;
-///     let mock_string: &str = "Foo::Bar";
-///     let expected_string: String = "Bar".to_owned();
-///     let asserted_string: String = demodulize(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::string::demodulize::demodulize;
-///     let mock_string: &str = "Test::Foo::Bar";
-///     let expected_string: String = "Bar".to_owned();
-///     let asserted_string: String = demodulize(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-pub fn demodulize(non_demodulize_string: &str) -> String {
-    if non_demodulize_string.contains("::") {
-        let split_string: Vec<&str> = non_demodulize_string.split("::").collect();
-        to_class_case(split_string[split_string.len() - 1])
-    } else {
-        non_demodulize_string.to_owned()
-    }
-}
diff --git a/third_party/rust/Inflector/src/string/mod.rs b/third_party/rust/Inflector/src/string/mod.rs
deleted file mode 100644
index 72702881d3..0000000000
--- a/third_party/rust/Inflector/src/string/mod.rs
+++ /dev/null
@@ -1,23 +0,0 @@
-#![deny(warnings)]
-/// Provides demodulize a string.
-///
-/// Example string `Foo::Bar` becomes `Bar`
-#[cfg(feature = "heavyweight")]
-pub mod demodulize;
-/// Provides deconstantizea string.
-///
-/// Example string `Foo::Bar` becomes `Foo`
-#[cfg(feature = "heavyweight")]
-pub mod deconstantize;
-/// Provides conversion to plural strings.
-///
-/// Example string `FooBar` -> `FooBars`
-#[cfg(feature = "heavyweight")]
-pub mod pluralize;
-/// Provides conversion to singular strings.
-///
-/// Example string `FooBars` -> `FooBar`
-#[cfg(feature = "heavyweight")]
-pub mod singularize;
-
-mod constants;
diff --git a/third_party/rust/Inflector/src/string/pluralize/mod.rs b/third_party/rust/Inflector/src/string/pluralize/mod.rs
deleted file mode 100644
index 1caeea52e5..0000000000
--- a/third_party/rust/Inflector/src/string/pluralize/mod.rs
+++ /dev/null
@@ -1,194 +0,0 @@
-#![deny(warnings)]
-use regex::Regex;
-use string::constants::UNACCONTABLE_WORDS;
-
-macro_rules! add_rule{
-    ($r:ident, $rule:expr => $replace:expr) => {
-        $r.push((Regex::new($rule).unwrap(), $replace));
-    }
-}
-
-macro_rules! rules{
-    ($r:ident; $($rule:expr => $replace:expr), *) => {
-        $(
-            add_rule!{$r, $rule => $replace}
-        )*
-    }
-}
-
-
-lazy_static!{
-    static ref RULES: Vec<(Regex, &'static str)> = {
-        let mut r = Vec::with_capacity(24);
-        rules![r;
-               r"(\w*)s$" => "s",
-               r"(\w*([^aeiou]ese))$" => "",
-               r"(\w*(ax|test))is$" => "es",
-               r"(\w*(alias|[^aou]us|tlas|gas|ris))$" => "es",
-               r"(\w*(e[mn]u))s?$" => "s",
-               r"(\w*([^l]ias|[aeiou]las|[emjzr]as|[iu]am))$" => "",
-               r"(\w*(alumn|syllab|octop|vir|radi|nucle|fung|cact|stimul|termin|bacill|foc|uter|loc|strat))(?:us|i)$" => "i",
-               r"(\w*(alumn|alg|vertebr))(?:a|ae)$" => "ae",
-               r"(\w*(seraph|cherub))(?:im)?$" => "im",
-               r"(\w*(her|at|gr))o$" => "oes",
-               r"(\w*(agend|addend|millenni|dat|extrem|bacteri|desiderat|strat|candelabr|errat|ov|symposi|curricul|automat|quor))(?:a|um)$" => "a",
-               r"(\w*(apheli|hyperbat|periheli|asyndet|noumen|phenomen|criteri|organ|prolegomen|hedr|automat))(?:a|on)$" => "a",
-               r"(\w*)sis$" => "ses",
-               r"(\w*(kni|wi|li))fe$" => "ves",
-               r"(\w*(ar|l|ea|eo|oa|hoo))f$" => "ves",
-               r"(\w*([^aeiouy]|qu))y$" => "ies",
-               r"(\w*([^ch][ieo][ln]))ey$" => "ies",
-               r"(\w*(x|ch|ss|sh|zz)es)$" => "",
-               r"(\w*(x|ch|ss|sh|zz))$" => "es",
-               r"(\w*(matr|cod|mur|sil|vert|ind|append))(?:ix|ex)$" => "ices",
-               r"(\w*(m|l)(?:ice|ouse))$" => "ice",
-               r"(\w*(pe)(?:rson|ople))$" => "ople",
-               r"(\w*(child))(?:ren)?$" => "ren",
-               r"(\w*eaux)$" => ""
-        ];
-        r
-    };
-}
-
-macro_rules! special_cases{
-    ($s:ident, $($singular: expr => $plural:expr), *) => {
-        match &$s[..] {
-            $(
-                $singular => {
-                    return $plural.to_owned();
-                },
-            )*
-            _ => ()
-        }
-    }
-}
-
-
-/// Converts a `&str` to pluralized `String`
-///
-/// ```
-///     use inflector::string::pluralize::to_plural;
-///     let mock_string: &str = "foo_bar";
-///     let expected_string: String = "foo_bars".to_owned();
-///     let asserted_string: String = to_plural(mock_string);
-///     assert_eq!(asserted_string, expected_string);
-///
-/// ```
-/// ```
-///     use inflector::string::pluralize::to_plural;
-///     let mock_string: &str = "ox";
-///     let expected_string: String = "oxen".to_owned();
-///     let asserted_string: String = to_plural(mock_string);
-///     assert_eq!(asserted_string, expected_string);
-///
-/// ```
-/// ```
-///     use inflector::string::pluralize::to_plural;
-///     let mock_string: &str = "crate";
-///     let expected_string: String = "crates".to_owned();
-///     let asserted_string: String = to_plural(mock_string);
-///     assert_eq!(asserted_string, expected_string);
-///
-/// ```
-/// ```
-///     use inflector::string::pluralize::to_plural;
-///     let mock_string: &str = "boxes";
-///     let expected_string: String = "boxes".to_owned();
-///     let asserted_string: String = to_plural(mock_string);
-///     assert_eq!(asserted_string, expected_string);
-///
-/// ```
-/// ```
-///     use inflector::string::pluralize::to_plural;
-///     let mock_string: &str = "vengeance";
-///     let expected_string: String = "vengeance".to_owned();
-///     let asserted_string: String = to_plural(mock_string);
-///     assert_eq!(asserted_string, expected_string);
-///
-/// ```
-/// ```
-///     use inflector::string::pluralize::to_plural;
-///     let mock_string: &str = "yoga";
-///     let expected_string: String = "yoga".to_owned();
-///     let asserted_string: String = to_plural(mock_string);
-///     assert_eq!(asserted_string, expected_string);
-///
-/// ```
-/// ```
-///     use inflector::string::pluralize::to_plural;
-///     let mock_string: &str = "geometry";
-///     let expected_string: String = "geometries".to_owned();
-///     let asserted_string: String = to_plural(mock_string);
-///     assert_eq!(asserted_string, expected_string);
-///
-/// ```
-///
-pub fn to_plural(non_plural_string: &str) -> String {
-    if UNACCONTABLE_WORDS.contains(&non_plural_string.as_ref()) {
-        non_plural_string.to_owned()
-    } else {
-        special_cases![non_plural_string,
-            "ox" => "oxen",
-            "man" => "men",
-            "woman" => "women",
-            "die" => "dice",
-            "yes" => "yeses",
-            "foot" => "feet",
-            "eave" => "eaves",
-            "goose" => "geese",
-            "tooth" => "teeth",
-            "quiz" => "quizzes"
-        ];
-        for &(ref rule, replace) in RULES.iter().rev() {
-            if let Some(c) = rule.captures(&non_plural_string) {
-                if let Some(c) = c.get(1) {
-                    return format!("{}{}", c.as_str(), replace);
-                }
-            }
-        }
-
-        format!("{}s", non_plural_string)
-    }
-}
-
-
-#[cfg(test)]
-mod tests {
-
-    macro_rules! as_item {
-        ($i:item) => { $i };
-    }
-
-    macro_rules! make_tests{
-        ($($singular:ident => $plural:ident); *) =>{
-            $(
-                   as_item! {
-                       #[test]
-                       fn $singular(){
-                           assert_eq!(
-                               stringify!($plural),
-                               super::to_plural(stringify!($singular))
-                               );
-                       }
-                   }
-            )*
-        }
-    }
-
-    #[test]
-    fn boxes() {
-        assert_eq!("boxes", super::to_plural("box"));
-    }
-
-    make_tests!{
-        geometry => geometries;
-        ox => oxen;
-        woman => women;
-        test => tests;
-        axis => axes;
-        knife => knives;
-        agendum => agenda;
-        elf => elves;
-        zoology => zoology
-    }
-}
diff --git a/third_party/rust/Inflector/src/string/singularize/mod.rs b/third_party/rust/Inflector/src/string/singularize/mod.rs
deleted file mode 100644
index 60e0b51ca7..0000000000
--- a/third_party/rust/Inflector/src/string/singularize/mod.rs
+++ /dev/null
@@ -1,189 +0,0 @@
-use regex::Regex;
-use string::constants::UNACCONTABLE_WORDS;
-
-macro_rules! special_cases{
-    ($s:ident, $($singular: expr => $plural:expr), *) => {
-        match &$s[..] {
-            $(
-                $singular => {
-                    return $plural.to_owned();
-                },
-            )*
-            _ => ()
-        }
-    }
-}
-
-
-/// Converts a `&str` to singularized `String`
-///
-/// ```
-///     use inflector::string::singularize::to_singular;
-///     let mock_string: &str = "foo_bars";
-///     let expected_string: String = "foo_bar".to_owned();
-///     let asserted_string: String = to_singular(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::string::singularize::to_singular;
-///     let mock_string: &str = "oxen";
-///     let expected_string: String = "ox".to_owned();
-///     let asserted_string: String = to_singular(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::string::singularize::to_singular;
-///     let mock_string: &str = "crates";
-///     let expected_string: String = "crate".to_owned();
-///     let asserted_string: String = to_singular(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::string::singularize::to_singular;
-///     let mock_string: &str = "oxen";
-///     let expected_string: String = "ox".to_owned();
-///     let asserted_string: String = to_singular(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::string::singularize::to_singular;
-///     let mock_string: &str = "boxes";
-///     let expected_string: String = "box".to_owned();
-///     let asserted_string: String = to_singular(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::string::singularize::to_singular;
-///     let mock_string: &str = "vengeance";
-///     let expected_string: String = "vengeance".to_owned();
-///     let asserted_string: String = to_singular(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::string::singularize::to_singular;
-///     let mock_string: &str = "yoga";
-///     let expected_string: String = "yoga".to_owned();
-///     let asserted_string: String = to_singular(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-///
-pub fn to_singular(non_singular_string: &str) -> String {
-    if UNACCONTABLE_WORDS.contains(&non_singular_string.as_ref()) {
-        non_singular_string.to_owned()
-    } else {
-        special_cases![non_singular_string,
-            "oxen" => "ox",
-            "boxes" => "box",
-            "men" => "man",
-            "women" => "woman",
-            "dice" => "die",
-            "yeses" => "yes",
-            "feet" => "foot",
-            "eaves" => "eave",
-            "geese" => "goose",
-            "teeth" => "tooth",
-            "quizzes" => "quiz"
-        ];
-        for &(ref rule, replace) in RULES.iter().rev() {
-            if let Some(captures) = rule.captures(&non_singular_string) {
-                if let Some(c) = captures.get(1) {
-                    let mut buf = String::new();
-                    captures.expand(&format!("{}{}", c.as_str(), replace), &mut buf);
-                    return buf;
-                }
-            }
-        }
-
-        format!("{}", non_singular_string)
-    }
-}
-
-macro_rules! add_rule{
-    ($r:ident, $rule:expr => $replace:expr) => {
-        $r.push((Regex::new($rule).unwrap(), $replace));
-    }
-}
-
-macro_rules! rules{
-    ($r:ident; $($rule:expr => $replace:expr), *) => {
-        $(
-            add_rule!{$r, $rule => $replace}
-        )*
-    }
-}
-
-
-lazy_static!{
-    static ref RULES: Vec<(Regex, &'static str)> = {
-    let mut r = Vec::with_capacity(27);
-    rules![r;
-     r"(\w*)s$" => "",
-     r"(\w*)(ss)$" => "$2",
-     r"(n)ews$" => "ews",
-     r"(\w*)(o)es$" => "",
-     r"(\w*)([ti])a$" => "um",
-     r"((a)naly|(b)a|(d)iagno|(p)arenthe|(p)rogno|(s)ynop|(t)he)(sis|ses)$" => "sis",
-     r"(^analy)(sis|ses)$" => "sis",
-     r"(\w*)([^f])ves$" => "fe",
-     r"(\w*)(hive)s$" => "",
-     r"(\w*)(tive)s$" => "",
-     r"(\w*)([lr])ves$" => "f",
-     r"(\w*([^aeiouy]|qu))ies$" => "y",
-     r"(s)eries$" => "eries",
-     r"(m)ovies$" => "ovie",
-     r"(\w*)(x|ch|ss|sh)es$" => "$2",
-     r"(m|l)ice$" => "ouse",
-     r"(bus)(es)?$" => "",
-     r"(shoe)s$" => "",
-     r"(cris|test)(is|es)$" => "is",
-     r"^(a)x[ie]s$" => "xis",
-     r"(octop|vir)(us|i)$" => "us",
-     r"(alias|status)(es)?$" => "",
-     r"^(ox)en" => "",
-     r"(vert|ind)ices$" => "ex",
-     r"(matr)ices$" => "ix",
-     r"(quiz)zes$" => "",
-     r"(database)s$" => ""
-         ];
-     r
-    };
-}
-
-#[test]
-fn singularize_ies_suffix() {
-    assert_eq!("reply", to_singular("replies"));
-    assert_eq!("lady", to_singular("ladies"));
-    assert_eq!("soliloquy", to_singular("soliloquies"));
-}
-
-#[test]
-fn singularize_ss_suffix() {
-    assert_eq!("glass", to_singular("glass"));
-    assert_eq!("access", to_singular("access"));
-    assert_eq!("glass", to_singular("glasses"));
-    assert_eq!("witch", to_singular("witches"));
-    assert_eq!("dish", to_singular("dishes"));
-}
-
-#[test]
-fn singularize_string_if_a_regex_will_match() {
-    let expected_string: String = "ox".to_owned();
-    let asserted_string: String = to_singular("oxen");
-    assert!(expected_string == asserted_string);
-
-}
-
-#[test]
-fn singularize_string_returns_none_option_if_no_match() {
-    let expected_string: String = "bacon".to_owned();
-    let asserted_string: String = to_singular("bacon");
-
-    assert!(expected_string == asserted_string);
-}
diff --git a/third_party/rust/Inflector/src/suffix/foreignkey/mod.rs b/third_party/rust/Inflector/src/suffix/foreignkey/mod.rs
deleted file mode 100644
index e46696d4e7..0000000000
--- a/third_party/rust/Inflector/src/suffix/foreignkey/mod.rs
+++ /dev/null
@@ -1,139 +0,0 @@
-use cases::snakecase::to_snake_case;
-
-/// Converts a `&str` to a `foreign_key`
-///
-/// ```
-///     use inflector::suffix::foreignkey::to_foreign_key;
-///     let mock_string: &str = "foo_bar";
-///     let expected_string: String = "foo_bar_id".to_owned();
-///     let asserted_string: String = to_foreign_key(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::suffix::foreignkey::to_foreign_key;
-///     let mock_string: &str = "Foo bar";
-///     let expected_string: String = "foo_bar_id".to_owned();
-///     let asserted_string: String = to_foreign_key(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::suffix::foreignkey::to_foreign_key;
-///     let mock_string: &str = "Foo Bar";
-///     let expected_string: String = "foo_bar_id".to_owned();
-///     let asserted_string: String = to_foreign_key(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::suffix::foreignkey::to_foreign_key;
-///     let mock_string: &str = "Foo::Bar";
-///     let expected_string: String = "bar_id".to_owned();
-///     let asserted_string: String = to_foreign_key(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::suffix::foreignkey::to_foreign_key;
-///     let mock_string: &str = "Test::Foo::Bar";
-///     let expected_string: String = "bar_id".to_owned();
-///     let asserted_string: String = to_foreign_key(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::suffix::foreignkey::to_foreign_key;
-///     let mock_string: &str = "FooBar";
-///     let expected_string: String = "foo_bar_id".to_owned();
-///     let asserted_string: String = to_foreign_key(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::suffix::foreignkey::to_foreign_key;
-///     let mock_string: &str = "fooBar";
-///     let expected_string: String = "foo_bar_id".to_owned();
-///     let asserted_string: String = to_foreign_key(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-/// ```
-///     use inflector::suffix::foreignkey::to_foreign_key;
-///     let mock_string: &str = "fooBar3";
-///     let expected_string: String = "foo_bar_3_id".to_owned();
-///     let asserted_string: String = to_foreign_key(mock_string);
-///     assert!(asserted_string == expected_string);
-///
-/// ```
-pub fn to_foreign_key(non_foreign_key_string: &str) -> String {
-    if non_foreign_key_string.contains("::") {
-        let split_string: Vec<&str> = non_foreign_key_string.split("::").collect();
-        safe_convert(split_string[split_string.len() - 1])
-    } else {
-        safe_convert(non_foreign_key_string)
-    }
-}
-fn safe_convert(safe_string: &str) -> String {
-    let snake_cased: String = to_snake_case(safe_string);
-    if snake_cased.ends_with("_id") {
-        snake_cased
-    } else {
-        format!("{}{}", snake_cased, "_id")
-    }
-}
-
-/// Determines if a `&str` is a `foreign_key`
-///
-/// ```
-///     use inflector::suffix::foreignkey::is_foreign_key;
-///     let mock_string: &str = "Foo bar string that is really really long";
-///     let asserted_bool: bool = is_foreign_key(mock_string);
-///     assert!(asserted_bool == false);
-///
-/// ```
-/// ```
-///     use inflector::suffix::foreignkey::is_foreign_key;
-///     let mock_string: &str = "foo-bar-string-that-is-really-really-long";
-///     let asserted_bool: bool = is_foreign_key(mock_string);
-///     assert!(asserted_bool == false);
-///
-/// ```
-/// ```
-///     use inflector::suffix::foreignkey::is_foreign_key;
-///     let mock_string: &str = "FooBarIsAReallyReallyLongString";
-///     let asserted_bool: bool = is_foreign_key(mock_string);
-///     assert!(asserted_bool == false);
-///
-/// ```
-/// ```
-///     use inflector::suffix::foreignkey::is_foreign_key;
-///     let mock_string: &str = "Foo Bar Is A Really Really Long String";
-///     let asserted_bool: bool = is_foreign_key(mock_string);
-///     assert!(asserted_bool == false);
-///
-/// ```
-/// ```
-///     use inflector::suffix::foreignkey::is_foreign_key;
-///     let mock_string: &str = "fooBarIsAReallyReallyLongString";
-///     let asserted_bool: bool = is_foreign_key(mock_string);
-///     assert!(asserted_bool == false);
-///
-/// ```
-/// ```
-///     use inflector::suffix::foreignkey::is_foreign_key;
-///     let mock_string: &str = "foo_bar_string_that_is_really_really_long";
-///     let asserted_bool: bool = is_foreign_key(mock_string);
-///     assert!(asserted_bool == false);
-///
-/// ```
-/// ```
-///     use inflector::suffix::foreignkey::is_foreign_key;
-///     let mock_string: &str = "foo_bar_string_that_is_really_really_long_id";
-///     let asserted_bool: bool = is_foreign_key(mock_string);
-///     assert!(asserted_bool == true);
-///
-/// ```
-pub fn is_foreign_key(test_string: &str) -> bool {
-    to_foreign_key(test_string.clone()) == test_string
-}
diff --git a/third_party/rust/Inflector/src/suffix/mod.rs b/third_party/rust/Inflector/src/suffix/mod.rs
deleted file mode 100644
index 2083cd5881..0000000000
--- a/third_party/rust/Inflector/src/suffix/mod.rs
+++ /dev/null
@@ -1,5 +0,0 @@
-#![deny(warnings)]
-/// Provides foreign key conversion for String.
-///
-/// Example string `foo` becomes `foo_id`
-pub mod foreignkey;
diff --git a/third_party/rust/Inflector/tests/lib.rs b/third_party/rust/Inflector/tests/lib.rs
deleted file mode 100644
index 62d77f4b32..0000000000
--- a/third_party/rust/Inflector/tests/lib.rs
+++ /dev/null
@@ -1,162 +0,0 @@
-#![deny(warnings)]
-extern crate inflector;
-
-use inflector::Inflector;
-use inflector::InflectorNumbers;
-
-macro_rules! str_tests {
-    ( $($test_name:ident => $imp_trait:ident => $to_cast:expr => $casted:expr), *) => {
-        $(
-            #[test]
-            fn $test_name() {
-                assert_eq!($to_cast.$imp_trait(), $casted)
-            }
-        )*
-    }
-}
-
-macro_rules! string_tests {
-    ( $($test_name:ident => $imp_trait:ident => $to_cast:expr => $casted:expr), *) => {
-        $(
-            #[test]
-            fn $test_name() {
-                assert_eq!($to_cast.to_string().$imp_trait(), $casted)
-            }
-        )*
-    }
-}
-
-macro_rules! number_tests {
-    ( $($test_name:ident => $imp_trait:ident => $typ:ident => $to_cast:expr => $casted:expr), *) => {
-        $(
-            #[test]
-            fn $test_name() {
-                let to_cast: $typ = $to_cast;
-                assert_eq!(to_cast.$imp_trait(), $casted)
-            }
-        )*
-    }
-}
-
-macro_rules! gated_str_tests {
-    ( $($test_name:ident => $imp_trait:ident => $to_cast:expr => $casted:expr), *) => {
-        $(
-            #[test]
-            #[cfg(feature = "heavyweight")]
-            fn $test_name() {
-                assert_eq!($to_cast.$imp_trait(), $casted)
-            }
-        )*
-    }
-}
-
-macro_rules! gated_string_tests {
-    ( $($test_name:ident => $imp_trait:ident => $to_cast:expr => $casted:expr), *) => {
-        $(
-            #[test]
-            #[cfg(feature = "heavyweight")]
-            fn $test_name() {
-                assert_eq!($to_cast.to_string().$imp_trait(), $casted)
-            }
-        )*
-    }
-}
-
-str_tests![
-    str_to_camel => to_camel_case => "foo_bar" => "fooBar".to_string(),
-    str_is_camel => is_camel_case => "fooBar" => true,
-    str_is_not_camel => is_camel_case => "foo_bar" => false,
-    str_to_screaming_snake => to_screaming_snake_case => "fooBar" => "FOO_BAR".to_string(),
-    str_is_screaming_snake => is_screaming_snake_case => "FOO_BAR" => true,
-    str_is_not_screaming_snake => is_screaming_snake_case => "foo_bar" => false,
-    str_to_snake => to_snake_case => "fooBar" => "foo_bar".to_string(),
-    str_is_snake => is_snake_case => "foo_bar" => true,
-    str_is_not_snake => is_snake_case => "fooBar" => false,
-    str_to_kebab => to_kebab_case => "fooBar" => "foo-bar".to_string(),
-    str_is_kebab => is_kebab_case => "foo-bar" => true,
-    str_is_not_kebab => is_kebab_case => "fooBar" => false,
-    str_to_train => to_train_case => "fooBar" => "Foo-Bar".to_string(),
-    str_is_train => is_train_case => "Foo-Bar" => true,
-    str_is_not_train => is_train_case => "FOO-Bar" => false,
-    str_to_sentence => to_sentence_case => "fooBar" => "Foo bar".to_string(),
-    str_is_sentence => is_sentence_case => "Foo bar" => true,
-    str_is_not_sentence => is_sentence_case => "foo_bar" => false,
-    str_to_title => to_title_case => "fooBar" => "Foo Bar".to_string(),
-    str_is_title => is_title_case => "Foo Bar" => true,
-    str_is_not_title => is_title_case => "Foo_Bar" => false,
-    str_ordinalize  => ordinalize => "1" => "1st".to_string(),
-    str_deordinalize  => deordinalize => "1st" => "1".to_string(),
-    str_to_foreign_key => to_foreign_key => "Foo::Bar" => "bar_id".to_string(),
-    str_is_foreign_key => is_foreign_key => "bar_id" => true,
-    str_is_not_foreign_key => is_foreign_key => "bar" => false
-];
-
-gated_str_tests![
-    str_to_class_case => to_class_case => "foo" => "Foo".to_string(),
-    str_is_class_case => is_class_case => "Foo" => true,
-    str_is_not_class_case => is_class_case => "foo" => false,
-    str_to_table => to_table_case => "fooBar" => "foo_bars".to_string(),
-    str_is_table => is_table_case => "foo_bars" => true,
-    str_is_not_table => is_table_case => "fooBars" => false,
-    str_pluralize => to_plural => "crate" => "crates".to_string(),
-    str_singular => to_singular => "crates" => "crate".to_string(),
-    str_demodulize => demodulize => "Foo::Bar" => "Bar".to_string(),
-    str_deconstantize => deconstantize => "Foo::Bar" => "Foo".to_string()
-];
-
-string_tests![
-    string_to_camel => to_camel_case => "foo_bar".to_string() => "fooBar".to_string(),
-    string_is_camel => is_camel_case => "fooBar".to_string() => true,
-    string_is_not_camel => is_camel_case => "foo_bar".to_string() => false,
-    string_to_screaming_snake => to_screaming_snake_case => "fooBar".to_string() => "FOO_BAR".to_string(),
-    string_is_screaming_snake => is_screaming_snake_case => "FOO_BAR".to_string() => true,
-    string_is_not_screaming_snake => is_screaming_snake_case => "foo_bar".to_string() => false,
-    string_to_snake => to_snake_case => "fooBar".to_string() => "foo_bar".to_string(),
-    string_is_snake => is_snake_case => "foo_bar".to_string() => true,
-    string_is_not_snake => is_snake_case => "fooBar".to_string() => false,
-    string_to_kebab => to_kebab_case => "fooBar".to_string() => "foo-bar".to_string(),
-    string_is_kebab => is_kebab_case => "foo-bar".to_string() => true,
-    string_is_not_kebab => is_kebab_case => "fooBar".to_string() => false,
-    string_to_train => to_train_case => "fooBar".to_string() => "Foo-Bar".to_string(),
-    string_is_train => is_train_case => "Foo-Bar".to_string() => true,
-    string_is_not_train => is_train_case => "foo-Bar".to_string() => false,
-    string_to_sentence => to_sentence_case => "fooBar".to_string() => "Foo bar".to_string(),
-    string_is_sentence => is_sentence_case => "Foo bar".to_string() => true,
-    string_is_not_sentence => is_sentence_case => "fooBar".to_string() => false,
-    string_to_title => to_title_case => "fooBar".to_string() => "Foo Bar".to_string(),
-    string_is_title => is_title_case => "Foo Bar".to_string() => true,
-    string_is_not_title => is_title_case => "fooBar".to_string() => false,
-    string_ordinalize  => ordinalize => "1".to_string() => "1st".to_string(),
-    string_deordinalize  => deordinalize => "1st".to_string() => "1".to_string(),
-    string_to_foreign_key => to_foreign_key => "Foo::Bar".to_string() => "bar_id".to_string(),
-    string_is_foreign_key => is_foreign_key => "bar_id".to_string() => true,
-    string_is_not_foreign_key => is_foreign_key => "bar".to_string() => false
-];
-
-gated_string_tests![
-    string_to_class_case => to_class_case => "foo".to_string() => "Foo".to_string(),
-    string_is_class_case => is_class_case => "Foo".to_string() => true,
-    string_is_not_class_case => is_class_case => "ooBar".to_string() => false,
-    string_to_table => to_table_case => "fooBar".to_string() => "foo_bars".to_string(),
-    string_is_table => is_table_case => "foo_bars".to_string() => true,
-    string_is_not_table => is_table_case => "fooBar".to_string() => false,
-    string_pluralize => to_plural => "crate".to_string() => "crates".to_string(),
-    string_singular => to_singular => "crates".to_string() => "crate".to_string(),
-    string_demodulize => demodulize => "Foo::Bar".to_string() => "Bar".to_string(),
-    string_deconstantize => deconstantize => "Foo::Bar".to_string() => "Foo".to_string()
-];
-
-number_tests![
-    i8_ordinalize   => ordinalize => i8  => 1 => "1st".to_string(),
-    i16_ordinalize  => ordinalize => i16 => 1 => "1st".to_string(),
-    i32_ordinalize  => ordinalize => i32 => 1 => "1st".to_string(),
-    i64_ordinalize  => ordinalize => i64 => 1 => "1st".to_string(),
-    u8_ordinalize   => ordinalize => u8  => 1 => "1st".to_string(),
-    u16_ordinalize  => ordinalize => u16 => 1 => "1st".to_string(),
-    u32_ordinalize  => ordinalize => u32 => 1 => "1st".to_string(),
-    u64_ordinalize  => ordinalize => u64 => 1 => "1st".to_string(),
-    isize_ordinalize  => ordinalize => isize => 1 => "1st".to_string(),
-    usize_ordinalize  => ordinalize => usize => 1 => "1st".to_string(),
-    f32_ordinalize  => ordinalize => f32 => 1.0 => "1st".to_string(),
-    f64_ordinalize  => ordinalize => f64 => 1.0 => "1st".to_string()
-];
diff --git a/third_party/rust/ansi_term/.cargo-checksum.json b/third_party/rust/ansi_term/.cargo-checksum.json
deleted file mode 100644
index c1b9d1b6e2..0000000000
--- a/third_party/rust/ansi_term/.cargo-checksum.json
+++ /dev/null
@@ -1 +0,0 @@
-{"files":{"Cargo.toml":"48df4570f3bbfba5b3c19731a54abf70ac8608e4dab6f4dae6a694b18d6ad102","LICENCE":"a24742368cf773bbb8b6f0fcbe86ca4b802c2b7c081bc8bebf14ac38618e7c63","README.md":"779b02ebacd6f4d08e01ef289bd7976a4467054f40355593817fd6df7e8c9dd4","examples/colours.rs":"e4870671adb9574607e37a0e4145643f9047c881c310113de114ec20d76aaf4b","src/ansi.rs":"b8f5de966e7ec2fba7a4d5a373d0aceafe19ea6e20a3f4daaf448e119c989ae7","src/debug.rs":"0ab28b65c39538825707d8b7e81c6f91c78310856c936bba0ee609e06d138543","src/difference.rs":"da68156310cbaf57a3619160d0fb966f496f970c32a2e57601127cc8f54a2fbf","src/display.rs":"a43f19b7cf4d95e90e4f3954399405d8350523d423f0beed9f01399e17527b17","src/lib.rs":"b6df00ab61ca0d82c9f7b3798d516384dd2617fe73e8981f37125ecccc970dd7","src/style.rs":"7c5c2524428f0dfbe3b8d5876ddb81c47d8635704ee31ef63ddeb2429a67f457","src/windows.rs":"3b52469eed89fdc258139e4fd978f0e30c72168863966247df781da8715f0841","src/write.rs":"247c518f8b0c103c970bbe7bc70caba3ee961ab0d37095e2da5c69db98d2fc24"},"package":"ee49baf6cb617b853aa8d93bf420db2383fab46d314482ca2803b40d5fde979b"}
\ No newline at end of file
diff --git a/third_party/rust/ansi_term/Cargo.toml b/third_party/rust/ansi_term/Cargo.toml
deleted file mode 100644
index 56a7f2d36f..0000000000
--- a/third_party/rust/ansi_term/Cargo.toml
+++ /dev/null
@@ -1,27 +0,0 @@
-# THIS FILE IS AUTOMATICALLY GENERATED BY CARGO
-#
-# When uploading crates to the registry Cargo will automatically
-# "normalize" Cargo.toml files for maximal compatibility
-# with all versions of Cargo and also rewrite `path` dependencies
-# to registry (e.g. crates.io) dependencies
-#
-# If you believe there's an error in this file please file an
-# issue against the rust-lang/cargo repository. If you're
-# editing this file be aware that the upstream Cargo.toml
-# will likely look very different (and much more reasonable)
-
-[package]
-name = "ansi_term"
-version = "0.11.0"
-authors = ["ogham@bsago.me", "Ryan Scheel (Havvy) <ryan.havvy@gmail.com>", "Josh Triplett <josh@joshtriplett.org>"]
-description = "Library for ANSI terminal colours and styles (bold, underline)"
-homepage = "https://github.com/ogham/rust-ansi-term"
-documentation = "https://docs.rs/ansi_term"
-readme = "README.md"
-license = "MIT"
-
-[lib]
-name = "ansi_term"
-[target."cfg(target_os=\"windows\")".dependencies.winapi]
-version = "0.3.4"
-features = ["errhandlingapi", "consoleapi", "processenv"]
diff --git a/third_party/rust/ansi_term/LICENCE b/third_party/rust/ansi_term/LICENCE
deleted file mode 100644
index 3f39e72bd6..0000000000
--- a/third_party/rust/ansi_term/LICENCE
+++ /dev/null
@@ -1,21 +0,0 @@
-The MIT License (MIT)
-
-Copyright (c) 2014 Benjamin Sago
-
-Permission is hereby granted, free of charge, to any person obtaining a copy
-of this software and associated documentation files (the "Software"), to deal
-in the Software without restriction, including without limitation the rights
-to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-copies of the Software, and to permit persons to whom the Software is
-furnished to do so, subject to the following conditions:
-
-The above copyright notice and this permission notice shall be included in all
-copies or substantial portions of the Software.
-
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-SOFTWARE.
diff --git a/third_party/rust/ansi_term/README.md b/third_party/rust/ansi_term/README.md
deleted file mode 100644
index 1cb56a19a2..0000000000
--- a/third_party/rust/ansi_term/README.md
+++ /dev/null
@@ -1,174 +0,0 @@
-# rust-ansi-term [![ansi-term on crates.io](http://meritbadge.herokuapp.com/ansi-term)](https://crates.io/crates/ansi_term) [![Build status](https://travis-ci.org/ogham/rust-ansi-term.svg?branch=master)](https://travis-ci.org/ogham/rust-ansi-term) [![Coverage status](https://coveralls.io/repos/ogham/rust-ansi-term/badge.svg?branch=master&service=github)](https://coveralls.io/github/ogham/rust-ansi-term?branch=master)
-
-This is a library for controlling colours and formatting, such as red bold text or blue underlined text, on ANSI terminals.
-
-### [View the Rustdoc](https://docs.rs/ansi_term/0.9.0/ansi_term/)
-
-
-# Installation
-
-This crate works with [Cargo](http://crates.io). Add the following to your `Cargo.toml` dependencies section:
-
-```toml
-[dependencies]
-ansi_term = "0.9"
-```
-
-
-## Basic usage
-
-There are two main data structures in this crate that you need to be concerned with: `ANSIString` and `Style`.
-A `Style` holds stylistic information: colours, whether the text should be bold, or blinking, or whatever.
-There are also `Colour` variants that represent simple foreground colour styles.
-An `ANSIString` is a string paired with a `Style`.
-
-(Yes, it’s British English, but you won’t have to write “colour” very often. `Style` is used the majority of the time.)
-
-To format a string, call the `paint` method on a `Style` or a `Colour`, passing in the string you want to format as the argument.
-For example, here’s how to get some red text:
-
-```rust
-use ansi_term::Colour::Red;
-println!("This is in red: {}", Red.paint("a red string"));
-```
-
-It’s important to note that the `paint` method does *not* actually return a string with the ANSI control characters surrounding it.
-Instead, it returns an `ANSIString` value that has a `Display` implementation that, when formatted, returns the characters.
-This allows strings to be printed with a minimum of `String` allocations being performed behind the scenes.
-
-If you *do* want to get at the escape codes, then you can convert the `ANSIString` to a string as you would any other `Display` value:
-
-```rust
-use ansi_term::Colour::Red;
-use std::string::ToString;
-let red_string = Red.paint("a red string").to_string();
-```
-
-**Note for Windows 10 users:** On Windows 10, the application must enable ANSI support first:
-
-```rust
-let enabled = ansi_term::enable_ansi_support();
-```
-
-## Bold, underline, background, and other styles
-
-For anything more complex than plain foreground colour changes, you need to construct `Style` objects themselves, rather than beginning with a `Colour`.
-You can do this by chaining methods based on a new `Style`, created with `Style::new()`.
-Each method creates a new style that has that specific property set.
-For example:
-
-```rust
-use ansi_term::Style;
-println!("How about some {} and {}?",
-         Style::new().bold().paint("bold"),
-         Style::new().underline().paint("underline"));
-```
-
-For brevity, these methods have also been implemented for `Colour` values, so you can give your styles a foreground colour without having to begin with an empty `Style` value:
-
-```rust
-use ansi_term::Colour::{Blue, Yellow};
-println!("Demonstrating {} and {}!",
-         Blue.bold().paint("blue bold"),
-         Yellow.underline().paint("yellow underline"));
-println!("Yellow on blue: {}", Yellow.on(Blue).paint("wow!"));
-```
-
-The complete list of styles you can use are:
-`bold`, `dimmed`, `italic`, `underline`, `blink`, `reverse`, `hidden`, and `on` for background colours.
-
-In some cases, you may find it easier to change the foreground on an existing `Style` rather than starting from the appropriate `Colour`.
-You can do this using the `fg` method:
-
-```rust
-    use ansi_term::Style;
-    use ansi_term::Colour::{Blue, Cyan, Yellow};
-    println!("Yellow on blue: {}", Style::new().on(Blue).fg(Yellow).paint("yow!"));
-    println!("Also yellow on blue: {}", Cyan.on(Blue).fg(Yellow).paint("zow!"));
-```
-
-Finally, you can turn a `Colour` into a `Style` with the `normal` method.
-This will produce the exact same `ANSIString` as if you just used the `paint` method on the `Colour` directly, but it’s useful in certain cases: for example, you may have a method that returns `Styles`, and need to represent both the “red bold” and “red, but not bold” styles with values of the same type. The `Style` struct also has a `Default` implementation if you want to have a style with *nothing* set.
-
-```rust
-use ansi_term::Style;
-use ansi_term::Colour::Red;
-Red.normal().paint("yet another red string");
-Style::default().paint("a completely regular string");
-```
-
-
-## Extended colours
-
-You can access the extended range of 256 colours by using the `Fixed` colour variant, which takes an argument of the colour number to use.
-This can be included wherever you would use a `Colour`:
-
-```rust
-use ansi_term::Colour::Fixed;
-Fixed(134).paint("A sort of light purple");
-Fixed(221).on(Fixed(124)).paint("Mustard in the ketchup");
-```
-
-The first sixteen of these values are the same as the normal and bold standard colour variants.
-There’s nothing stopping you from using these as `Fixed` colours instead, but there’s nothing to be gained by doing so either.
-
-You can also access full 24-bit color by using the `RGB` colour variant, which takes separate `u8` arguments for red, green, and blue:
-
-```rust
-    use ansi_term::Colour::RGB;
-    RGB(70, 130, 180).paint("Steel blue");
-```
-
-## Combining successive coloured strings
-
-The benefit of writing ANSI escape codes to the terminal is that they *stack*: you do not need to end every coloured string with a reset code if the text that follows it is of a similar style.
-For example, if you want to have some blue text followed by some blue bold text, it’s possible to send the ANSI code for blue, followed by the ANSI code for bold, and finishing with a reset code without having to have an extra one between the two strings.
-
-This crate can optimise the ANSI codes that get printed in situations like this, making life easier for your terminal renderer.
-The `ANSIStrings` struct takes a slice of several `ANSIString` values, and will iterate over each of them, printing only the codes for the styles that need to be updated as part of its formatting routine.
-
-The following code snippet uses this to enclose a binary number displayed in red bold text inside some red, but not bold, brackets:
-
-```rust
-use ansi_term::Colour::Red;
-use ansi_term::{ANSIString, ANSIStrings};
-let some_value = format!("{:b}", 42);
-let strings: &[ANSIString<'static>] = &[
-    Red.paint("["),
-    Red.bold().paint(some_value),
-    Red.paint("]"),
-];
-println!("Value: {}", ANSIStrings(strings));
-```
-
-There are several things to note here.
-Firstly, the `paint` method can take *either* an owned `String` or a borrowed `&str`.
-Internally, an `ANSIString` holds a copy-on-write (`Cow`) string value to deal with both owned and borrowed strings at the same time.
-This is used here to display a `String`, the result of the `format!` call, using the same mechanism as some statically-available `&str` slices.
-Secondly, that the `ANSIStrings` value works in the same way as its singular counterpart, with a `Display` implementation that only performs the formatting when required.
-
-## Byte strings
-
-This library also supports formatting `[u8]` byte strings; this supports
-applications working with text in an unknown encoding.  `Style` and
-`Color` support painting `[u8]` values, resulting in an `ANSIByteString`.
-This type does not implement `Display`, as it may not contain UTF-8, but
-it does provide a method `write_to` to write the result to any
-`io::Write`:
-
-```rust
-use ansi_term::Colour::Green;
-Green.paint("user data".as_bytes()).write_to(&mut std::io::stdout()).unwrap();
-```
-
-Similarly, the type `ANSIByteStrings` supports writing a list of
-`ANSIByteString` values with minimal escape sequences:
-
-```rust
-use ansi_term::Colour::Green;
-use ansi_term::ANSIByteStrings;
-ANSIByteStrings(&[
-    Green.paint("user data 1\n".as_bytes()),
-    Green.bold().paint("user data 2\n".as_bytes()),
-]).write_to(&mut std::io::stdout()).unwrap();
-```
diff --git a/third_party/rust/ansi_term/examples/colours.rs b/third_party/rust/ansi_term/examples/colours.rs
deleted file mode 100644
index 1870310631..0000000000
--- a/third_party/rust/ansi_term/examples/colours.rs
+++ /dev/null
@@ -1,13 +0,0 @@
-extern crate ansi_term;
-use ansi_term::Colour::*;
-
-fn main() {
-    println!("{}", Black.paint("Black"));
-    println!("{}", Red.paint("Red"));
-    println!("{}", Green.paint("Green"));
-    println!("{}", Yellow.paint("Yellow"));
-    println!("{}", Blue.paint("Blue"));
-    println!("{}", Purple.paint("Purple"));
-    println!("{}", Cyan.paint("Cyan"));
-    println!("{}", White.paint("White"));
-}
diff --git a/third_party/rust/ansi_term/src/ansi.rs b/third_party/rust/ansi_term/src/ansi.rs
deleted file mode 100644
index 009043ff75..0000000000
--- a/third_party/rust/ansi_term/src/ansi.rs
+++ /dev/null
@@ -1,258 +0,0 @@
-use style::{Colour, Style};
-
-use std::fmt;
-
-use write::AnyWrite;
-
-
-// ---- generating ANSI codes ----
-
-impl Style {
-
-    /// Write any ANSI codes that go *before* a piece of text. These should be
-    /// the codes to set the terminal to a different colour or font style.
-    fn write_prefix<W: AnyWrite + ?Sized>(&self, f: &mut W) -> Result<(), W::Error> {
-
-        // If there are actually no styles here, then don’t write *any* codes
-        // as the prefix. An empty ANSI code may not affect the terminal
-        // output at all, but a user may just want a code-free string.
-        if self.is_plain() {
-            return Ok(());
-        }
-
-        // Write the codes’ prefix, then write numbers, separated by
-        // semicolons, for each text style we want to apply.
-        write!(f, "\x1B[")?;
-        let mut written_anything = false;
-
-        {
-            let mut write_char = |c| {
-                if written_anything { write!(f, ";")?; }
-                written_anything = true;
-                write!(f, "{}", c)?;
-                Ok(())
-            };
-
-            if self.is_bold           { write_char('1')? }
-            if self.is_dimmed         { write_char('2')? }
-            if self.is_italic         { write_char('3')? }
-            if self.is_underline      { write_char('4')? }
-            if self.is_blink          { write_char('5')? }
-            if self.is_reverse        { write_char('7')? }
-            if self.is_hidden         { write_char('8')? }
-            if self.is_strikethrough  { write_char('9')? }
-        }
-
-        // The foreground and background colours, if specified, need to be
-        // handled specially because the number codes are more complicated.
-        // (see `write_background_code` and `write_foreground_code`)
-        if let Some(bg) = self.background {
-            if written_anything { write!(f, ";")?; }
-            written_anything = true;
-            bg.write_background_code(f)?;
-        }
-
-        if let Some(fg) = self.foreground {
-            if written_anything { write!(f, ";")?; }
-            fg.write_foreground_code(f)?;
-        }
-
-        // All the codes end with an `m`, because reasons.
-        write!(f, "m")?;
-
-        Ok(())
-    }
-
-    /// Write any ANSI codes that go *after* a piece of text. These should be
-    /// the codes to *reset* the terminal back to its normal colour and style.
-    fn write_suffix<W: AnyWrite + ?Sized>(&self, f: &mut W) -> Result<(), W::Error> {
-        if self.is_plain() {
-            Ok(())
-        }
-        else {
-            write!(f, "{}", RESET)
-        }
-    }
-}
-
-
-/// The code to send to reset all styles and return to `Style::default()`.
-pub static RESET: &str = "\x1B[0m";
-
-
-
-impl Colour {
-    fn write_foreground_code<W: AnyWrite + ?Sized>(&self, f: &mut W) -> Result<(), W::Error> {
-        match *self {
-            Colour::Black      => write!(f, "30"),
-            Colour::Red        => write!(f, "31"),
-            Colour::Green      => write!(f, "32"),
-            Colour::Yellow     => write!(f, "33"),
-            Colour::Blue       => write!(f, "34"),
-            Colour::Purple     => write!(f, "35"),
-            Colour::Cyan       => write!(f, "36"),
-            Colour::White      => write!(f, "37"),
-            Colour::Fixed(num) => write!(f, "38;5;{}", &num),
-            Colour::RGB(r,g,b) => write!(f, "38;2;{};{};{}", &r, &g, &b),
-        }
-    }
-
-    fn write_background_code<W: AnyWrite + ?Sized>(&self, f: &mut W) -> Result<(), W::Error> {
-        match *self {
-            Colour::Black      => write!(f, "40"),
-            Colour::Red        => write!(f, "41"),
-            Colour::Green      => write!(f, "42"),
-            Colour::Yellow     => write!(f, "43"),
-            Colour::Blue       => write!(f, "44"),
-            Colour::Purple     => write!(f, "45"),
-            Colour::Cyan       => write!(f, "46"),
-            Colour::White      => write!(f, "47"),
-            Colour::Fixed(num) => write!(f, "48;5;{}", &num),
-            Colour::RGB(r,g,b) => write!(f, "48;2;{};{};{}", &r, &g, &b),
-        }
-    }
-}
-
-
-/// Like `ANSIString`, but only displays the style prefix.
-#[derive(Clone, Copy, Debug)]
-pub struct Prefix(Style);
-
-/// Like `ANSIString`, but only displays the difference between two
-/// styles.
-#[derive(Clone, Copy, Debug)]
-pub struct Infix(Style, Style);
-
-/// Like `ANSIString`, but only displays the style suffix.
-#[derive(Clone, Copy, Debug)]
-pub struct Suffix(Style);
-
-
-impl Style {
-
-    /// The prefix for this style.
-    pub fn prefix(self) -> Prefix {
-        Prefix(self)
-    }
-
-    /// The infix between this style and another.
-    pub fn infix(self, other: Style) -> Infix {
-        Infix(self, other)
-    }
-
-    /// The suffix for this style.
-    pub fn suffix(self) -> Suffix {
-        Suffix(self)
-    }
-}
-
-
-impl Colour {
-
-    /// The prefix for this colour.
-    pub fn prefix(self) -> Prefix {
-        Prefix(self.normal())
-    }
-
-    /// The infix between this colour and another.
-    pub fn infix(self, other: Colour) -> Infix {
-        Infix(self.normal(), other.normal())
-    }
-
-    /// The suffix for this colour.
-    pub fn suffix(self) -> Suffix {
-        Suffix(self.normal())
-    }
-}
-
-
-impl fmt::Display for Prefix {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        let f: &mut fmt::Write = f;
-        self.0.write_prefix(f)
-    }
-}
-
-
-impl fmt::Display for Infix {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        use difference::Difference;
-
-        match Difference::between(&self.0, &self.1) {
-            Difference::ExtraStyles(style) => {
-                let f: &mut fmt::Write = f;
-                style.write_prefix(f)
-            },
-            Difference::Reset => {
-                let f: &mut fmt::Write = f;
-                write!(f, "{}{}", RESET, self.0.prefix())
-            },
-            Difference::NoDifference => {
-                Ok(())   // nothing to write
-            },
-        }
-    }
-}
-
-
-impl fmt::Display for Suffix {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        let f: &mut fmt::Write = f;
-        self.0.write_suffix(f)
-    }
-}
-
-
-
-#[cfg(test)]
-mod test {
-    use style::Style;
-    use style::Colour::*;
-
-    macro_rules! test {
-        ($name: ident: $style: expr; $input: expr => $result: expr) => {
-            #[test]
-            fn $name() {
-                assert_eq!($style.paint($input).to_string(), $result.to_string());
-
-                let mut v = Vec::new();
-                $style.paint($input.as_bytes()).write_to(&mut v).unwrap();
-                assert_eq!(v.as_slice(), $result.as_bytes());
-            }
-        };
-    }
-
-    test!(plain:                 Style::default();                  "text/plain" => "text/plain");
-    test!(red:                   Red;                               "hi" => "\x1B[31mhi\x1B[0m");
-    test!(black:                 Black.normal();                    "hi" => "\x1B[30mhi\x1B[0m");
-    test!(yellow_bold:           Yellow.bold();                     "hi" => "\x1B[1;33mhi\x1B[0m");
-    test!(yellow_bold_2:         Yellow.normal().bold();            "hi" => "\x1B[1;33mhi\x1B[0m");
-    test!(blue_underline:        Blue.underline();                  "hi" => "\x1B[4;34mhi\x1B[0m");
-    test!(green_bold_ul:         Green.bold().underline();          "hi" => "\x1B[1;4;32mhi\x1B[0m");
-    test!(green_bold_ul_2:       Green.underline().bold();          "hi" => "\x1B[1;4;32mhi\x1B[0m");
-    test!(purple_on_white:       Purple.on(White);                  "hi" => "\x1B[47;35mhi\x1B[0m");
-    test!(purple_on_white_2:     Purple.normal().on(White);         "hi" => "\x1B[47;35mhi\x1B[0m");
-    test!(yellow_on_blue:        Style::new().on(Blue).fg(Yellow);  "hi" => "\x1B[44;33mhi\x1B[0m");
-    test!(yellow_on_blue_2:      Cyan.on(Blue).fg(Yellow);          "hi" => "\x1B[44;33mhi\x1B[0m");
-    test!(cyan_bold_on_white:    Cyan.bold().on(White);             "hi" => "\x1B[1;47;36mhi\x1B[0m");
-    test!(cyan_ul_on_white:      Cyan.underline().on(White);        "hi" => "\x1B[4;47;36mhi\x1B[0m");
-    test!(cyan_bold_ul_on_white: Cyan.bold().underline().on(White); "hi" => "\x1B[1;4;47;36mhi\x1B[0m");
-    test!(cyan_ul_bold_on_white: Cyan.underline().bold().on(White); "hi" => "\x1B[1;4;47;36mhi\x1B[0m");
-    test!(fixed:                 Fixed(100);                        "hi" => "\x1B[38;5;100mhi\x1B[0m");
-    test!(fixed_on_purple:       Fixed(100).on(Purple);             "hi" => "\x1B[45;38;5;100mhi\x1B[0m");
-    test!(fixed_on_fixed:        Fixed(100).on(Fixed(200));         "hi" => "\x1B[48;5;200;38;5;100mhi\x1B[0m");
-    test!(rgb:                   RGB(70,130,180);                   "hi" => "\x1B[38;2;70;130;180mhi\x1B[0m");
-    test!(rgb_on_blue:           RGB(70,130,180).on(Blue);          "hi" => "\x1B[44;38;2;70;130;180mhi\x1B[0m");
-    test!(blue_on_rgb:           Blue.on(RGB(70,130,180));          "hi" => "\x1B[48;2;70;130;180;34mhi\x1B[0m");
-    test!(rgb_on_rgb:            RGB(70,130,180).on(RGB(5,10,15));  "hi" => "\x1B[48;2;5;10;15;38;2;70;130;180mhi\x1B[0m");
-    test!(bold:                  Style::new().bold();               "hi" => "\x1B[1mhi\x1B[0m");
-    test!(underline:             Style::new().underline();          "hi" => "\x1B[4mhi\x1B[0m");
-    test!(bunderline:            Style::new().bold().underline();   "hi" => "\x1B[1;4mhi\x1B[0m");
-    test!(dimmed:                Style::new().dimmed();             "hi" => "\x1B[2mhi\x1B[0m");
-    test!(italic:                Style::new().italic();             "hi" => "\x1B[3mhi\x1B[0m");
-    test!(blink:                 Style::new().blink();              "hi" => "\x1B[5mhi\x1B[0m");
-    test!(reverse:               Style::new().reverse();            "hi" => "\x1B[7mhi\x1B[0m");
-    test!(hidden:                Style::new().hidden();             "hi" => "\x1B[8mhi\x1B[0m");
-    test!(stricken:              Style::new().strikethrough();      "hi" => "\x1B[9mhi\x1B[0m");
-
-}
diff --git a/third_party/rust/ansi_term/src/debug.rs b/third_party/rust/ansi_term/src/debug.rs
deleted file mode 100644
index da30c625cd..0000000000
--- a/third_party/rust/ansi_term/src/debug.rs
+++ /dev/null
@@ -1,122 +0,0 @@
-use std::fmt;
-
-use style::Style;
-
-
-/// Styles have a special `Debug` implementation that only shows the fields that
-/// are set. Fields that haven’t been touched aren’t included in the output.
-///
-/// This behaviour gets bypassed when using the alternate formatting mode
-/// `format!("{:#?}")`.
-///
-///     use ansi_term::Colour::{Red, Blue};
-///     assert_eq!("Style { fg(Red), on(Blue), bold, italic }",
-///                format!("{:?}", Red.on(Blue).bold().italic()));
-impl fmt::Debug for Style {
-    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
-        if fmt.alternate() {
-            fmt.debug_struct("Style")
-               .field("foreground",    &self.foreground)
-               .field("background",    &self.background)
-               .field("blink",         &self.is_blink)
-               .field("bold",          &self.is_bold)
-               .field("dimmed",        &self.is_dimmed)
-               .field("hidden",        &self.is_hidden)
-               .field("italic",        &self.is_italic)
-               .field("reverse",       &self.is_reverse)
-               .field("strikethrough", &self.is_strikethrough)
-               .field("underline",     &self.is_underline)
-               .finish()
-        }
-        else if self.is_plain() {
-            fmt.write_str("Style {}")
-        }
-        else {
-            fmt.write_str("Style { ")?;
-
-            let mut written_anything = false;
-
-            if let Some(fg) = self.foreground {
-                if written_anything { fmt.write_str(", ")? }
-                written_anything = true;
-                write!(fmt, "fg({:?})", fg)?
-            }
-
-            if let Some(bg) = self.background {
-                if written_anything { fmt.write_str(", ")? }
-                written_anything = true;
-                write!(fmt, "on({:?})", bg)?
-            }
-
-            {
-                let mut write_flag = |name| {
-                    if written_anything { fmt.write_str(", ")? }
-                    written_anything = true;
-                    fmt.write_str(name)
-                };
-
-                if self.is_blink          { write_flag("blink")? }
-                if self.is_bold           { write_flag("bold")? }
-                if self.is_dimmed         { write_flag("dimmed")? }
-                if self.is_hidden         { write_flag("hidden")? }
-                if self.is_italic         { write_flag("italic")? }
-                if self.is_reverse        { write_flag("reverse")? }
-                if self.is_strikethrough  { write_flag("strikethrough")? }
-                if self.is_underline      { write_flag("underline")? }
-            }
-
-            write!(fmt, " }}")
-        }
-    }
-}
-
-
-#[cfg(test)]
-mod test {
-    use style::Colour::*;
-    use style::Style;
-
-    fn style() -> Style {
-        Style::new()
-    }
-
-    macro_rules! test {
-        ($name: ident: $obj: expr => $result: expr) => {
-            #[test]
-            fn $name() {
-                assert_eq!($result, format!("{:?}", $obj));
-            }
-        };
-    }
-
-    test!(empty:   style()                  => "Style {}");
-    test!(bold:    style().bold()           => "Style { bold }");
-    test!(italic:  style().italic()         => "Style { italic }");
-    test!(both:    style().bold().italic()  => "Style { bold, italic }");
-
-    test!(red:     Red.normal()                     => "Style { fg(Red) }");
-    test!(redblue: Red.normal().on(RGB(3, 2, 4))    => "Style { fg(Red), on(RGB(3, 2, 4)) }");
-
-    test!(everything:
-            Red.on(Blue).blink().bold().dimmed().hidden().italic().reverse().strikethrough().underline() =>
-            "Style { fg(Red), on(Blue), blink, bold, dimmed, hidden, italic, reverse, strikethrough, underline }");
-
-    #[test]
-    fn long_and_detailed() {
-        let debug = r##"Style {
-    foreground: Some(
-        Blue
-    ),
-    background: None,
-    blink: false,
-    bold: true,
-    dimmed: false,
-    hidden: false,
-    italic: false,
-    reverse: false,
-    strikethrough: false,
-    underline: false
-}"##;
-        assert_eq!(debug, format!("{:#?}", Blue.bold()));
-    }
-}
diff --git a/third_party/rust/ansi_term/src/difference.rs b/third_party/rust/ansi_term/src/difference.rs
deleted file mode 100644
index 571574634f..0000000000
--- a/third_party/rust/ansi_term/src/difference.rs
+++ /dev/null
@@ -1,179 +0,0 @@
-use super::Style;
-
-
-/// When printing out one coloured string followed by another, use one of
-/// these rules to figure out which *extra* control codes need to be sent.
-#[derive(PartialEq, Clone, Copy, Debug)]
-pub enum Difference {
-
-    /// Print out the control codes specified by this style to end up looking
-    /// like the second string's styles.
-    ExtraStyles(Style),
-
-    /// Converting between these two is impossible, so just send a reset
-    /// command and then the second string's styles.
-    Reset,
-
-    /// The before style is exactly the same as the after style, so no further
-    /// control codes need to be printed.
-    NoDifference,
-}
-
-
-impl Difference {
-
-    /// Compute the 'style difference' required to turn an existing style into
-    /// the given, second style.
-    ///
-    /// For example, to turn green text into green bold text, it's redundant
-    /// to write a reset command then a second green+bold command, instead of
-    /// just writing one bold command. This method should see that both styles
-    /// use the foreground colour green, and reduce it to a single command.
-    ///
-    /// This method returns an enum value because it's not actually always
-    /// possible to turn one style into another: for example, text could be
-    /// made bold and underlined, but you can't remove the bold property
-    /// without also removing the underline property. So when this has to
-    /// happen, this function returns None, meaning that the entire set of
-    /// styles should be reset and begun again.
-    pub fn between(first: &Style, next: &Style) -> Difference {
-        use self::Difference::*;
-
-        // XXX(Havvy): This algorithm is kind of hard to replicate without
-        // having the Plain/Foreground enum variants, so I'm just leaving
-        // it commented out for now, and defaulting to Reset.
-
-        if first == next {
-            return NoDifference;
-        }
-
-        // Cannot un-bold, so must Reset.
-        if first.is_bold && !next.is_bold {
-            return Reset;
-        }
-
-        if first.is_dimmed && !next.is_dimmed {
-            return Reset;
-        }
-
-        if first.is_italic && !next.is_italic {
-            return Reset;
-        }
-
-        // Cannot un-underline, so must Reset.
-        if first.is_underline && !next.is_underline {
-            return Reset;
-        }
-
-        if first.is_blink && !next.is_blink {
-            return Reset;
-        }
-
-        if first.is_reverse && !next.is_reverse {
-            return Reset;
-        }
-
-        if first.is_hidden && !next.is_hidden {
-            return Reset;
-        }
-
-        if first.is_strikethrough && !next.is_strikethrough {
-            return Reset;
-        }
-
-        // Cannot go from foreground to no foreground, so must Reset.
-        if first.foreground.is_some() && next.foreground.is_none() {
-            return Reset;
-        }
-
-        // Cannot go from background to no background, so must Reset.
-        if first.background.is_some() && next.background.is_none() {
-            return Reset;
-        }
-
-        let mut extra_styles = Style::default();
-
-        if first.is_bold != next.is_bold {
-            extra_styles.is_bold = true;
-        }
-
-        if first.is_dimmed != next.is_dimmed {
-            extra_styles.is_dimmed = true;
-        }
-
-        if first.is_italic != next.is_italic {
-            extra_styles.is_italic = true;
-        }
-
-        if first.is_underline != next.is_underline {
-            extra_styles.is_underline = true;
-        }
-
-        if first.is_blink != next.is_blink {
-            extra_styles.is_blink = true;
-        }
-
-        if first.is_reverse != next.is_reverse {
-            extra_styles.is_reverse = true;
-        }
-
-        if first.is_hidden != next.is_hidden {
-            extra_styles.is_hidden = true;
-        }
-
-        if first.is_strikethrough != next.is_strikethrough {
-            extra_styles.is_strikethrough = true;
-        }
-
-        if first.foreground != next.foreground {
-            extra_styles.foreground = next.foreground;
-        }
-
-        if first.background != next.background {
-            extra_styles.background = next.background;
-        }
-
-        ExtraStyles(extra_styles)
-    }
-}
-
-
-#[cfg(test)]
-mod test {
-    use super::*;
-    use super::Difference::*;
-    use style::Colour::*;
-    use style::Style;
-
-    fn style() -> Style {
-        Style::new()
-    }
-
-    macro_rules! test {
-        ($name: ident: $first: expr; $next: expr => $result: expr) => {
-            #[test]
-            fn $name() {
-                assert_eq!($result, Difference::between(&$first, &$next));
-            }
-        };
-    }
-
-    test!(nothing:    Green.normal(); Green.normal()  => NoDifference);
-    test!(uppercase:  Green.normal(); Green.bold()    => ExtraStyles(style().bold()));
-    test!(lowercase:  Green.bold();   Green.normal()  => Reset);
-    test!(nothing2:   Green.bold();   Green.bold()    => NoDifference);
-
-    test!(colour_change: Red.normal(); Blue.normal() => ExtraStyles(Blue.normal()));
-
-    test!(addition_of_blink:          style(); style().blink()          => ExtraStyles(style().blink()));
-    test!(addition_of_dimmed:         style(); style().dimmed()         => ExtraStyles(style().dimmed()));
-    test!(addition_of_hidden:         style(); style().hidden()         => ExtraStyles(style().hidden()));
-    test!(addition_of_reverse:        style(); style().reverse()        => ExtraStyles(style().reverse()));
-    test!(addition_of_strikethrough:  style(); style().strikethrough()  => ExtraStyles(style().strikethrough()));
-
-    test!(removal_of_strikethrough:   style().strikethrough(); style()  => Reset);
-    test!(removal_of_reverse:         style().reverse();       style()  => Reset);
-    test!(removal_of_hidden:          style().hidden();        style()  => Reset);
-    test!(removal_of_dimmed:          style().dimmed();        style()  => Reset);
-    test!(removal_of_blink:           style().blink();         style()  => Reset);
-}
diff --git a/third_party/rust/ansi_term/src/display.rs b/third_party/rust/ansi_term/src/display.rs
deleted file mode 100644
index 8314ab85fa..0000000000
--- a/third_party/rust/ansi_term/src/display.rs
+++ /dev/null
@@ -1,279 +0,0 @@
-use std::borrow::Cow;
-use std::fmt;
-use std::io;
-use std::ops::Deref;
-
-use ansi::RESET;
-use difference::Difference;
-use style::{Style, Colour};
-use write::AnyWrite;
-
-
-/// An `ANSIGenericString` includes a generic string type and a `Style` to
-/// display that string.  `ANSIString` and `ANSIByteString` are aliases for
-/// this type on `str` and `[u8]`, respectively.
-#[derive(PartialEq, Debug)]
-pub struct ANSIGenericString<'a, S: 'a + ToOwned + ?Sized>
-where <S as ToOwned>::Owned: fmt::Debug {
-    style: Style,
-    string: Cow<'a, S>,
-}
-
-
-/// Cloning an `ANSIGenericString` will clone its underlying string.
-///
-/// ### Examples
-///
-/// ```
-/// use ansi_term::ANSIString;
-///
-/// let plain_string = ANSIString::from("a plain string");
-/// let clone_string = plain_string.clone();
-/// assert_eq!(clone_string, plain_string);
-/// ```
-impl<'a, S: 'a + ToOwned + ?Sized> Clone for ANSIGenericString<'a, S>
-where <S as ToOwned>::Owned: fmt::Debug {
-    fn clone(&self) -> ANSIGenericString<'a, S> {
-        ANSIGenericString {
-            style: self.style,
-            string: self.string.clone(),
-        }
-    }
-}
-
-// You might think that the hand-written Clone impl above is the same as the
-// one that gets generated with #[derive]. But it’s not *quite* the same!
-//
-// `str` is not Clone, and the derived Clone implementation puts a Clone
-// constraint on the S type parameter (generated using --pretty=expanded):
-//
-//                  ↓_________________↓
-//     impl <'a, S: ::std::clone::Clone + 'a + ToOwned + ?Sized> ::std::clone::Clone
-//     for ANSIGenericString<'a, S> where
-//     <S as ToOwned>::Owned: fmt::Debug { ... }
-//
-// This resulted in compile errors when you tried to derive Clone on a type
-// that used it:
-//
-//     #[derive(PartialEq, Debug, Clone, Default)]
-//     pub struct TextCellContents(Vec<ANSIString<'static>>);
-//                                 ^^^^^^^^^^^^^^^^^^^^^^^^^
-//     error[E0277]: the trait `std::clone::Clone` is not implemented for `str`
-//
-// The hand-written impl above can ignore that constraint and still compile.
-
-
-
-/// An ANSI String is a string coupled with the `Style` to display it
-/// in a terminal.
-///
-/// Although not technically a string itself, it can be turned into
-/// one with the `to_string` method.
-///
-/// ### Examples
-///
-/// ```no_run
-/// use ansi_term::ANSIString;
-/// use ansi_term::Colour::Red;
-///
-/// let red_string = Red.paint("a red string");
-/// println!("{}", red_string);
-/// ```
-///
-/// ```
-/// use ansi_term::ANSIString;
-///
-/// let plain_string = ANSIString::from("a plain string");
-/// assert_eq!(&*plain_string, "a plain string");
-/// ```
-pub type ANSIString<'a> = ANSIGenericString<'a, str>;
-
-/// An `ANSIByteString` represents a formatted series of bytes.  Use
-/// `ANSIByteString` when styling text with an unknown encoding.
-pub type ANSIByteString<'a> = ANSIGenericString<'a, [u8]>;
-
-impl<'a, I, S: 'a + ToOwned + ?Sized> From<I> for ANSIGenericString<'a, S>
-where I: Into<Cow<'a, S>>,
-      <S as ToOwned>::Owned: fmt::Debug {
-    fn from(input: I) -> ANSIGenericString<'a, S> {
-        ANSIGenericString {
-            string: input.into(),
-            style:  Style::default(),
-        }
-    }
-}
-
-impl<'a, S: 'a + ToOwned + ?Sized> Deref for ANSIGenericString<'a, S>
-where <S as ToOwned>::Owned: fmt::Debug {
-    type Target = S;
-
-    fn deref(&self) -> &S {
-        self.string.deref()
-    }
-}
-
-
-/// A set of `ANSIGenericString`s collected together, in order to be
-/// written with a minimum of control characters.
-pub struct ANSIGenericStrings<'a, S: 'a + ToOwned + ?Sized>
-    (pub &'a [ANSIGenericString<'a, S>])
-    where <S as ToOwned>::Owned: fmt::Debug;
-
-/// A set of `ANSIString`s collected together, in order to be written with a
-/// minimum of control characters.
-pub type ANSIStrings<'a> = ANSIGenericStrings<'a, str>;
-
-/// A function to construct an `ANSIStrings` instance.
-#[allow(non_snake_case)]
-pub fn ANSIStrings<'a>(arg: &'a [ANSIString<'a>]) -> ANSIStrings<'a> {
-    ANSIGenericStrings(arg)
-}
-
-/// A set of `ANSIByteString`s collected together, in order to be
-/// written with a minimum of control characters.
-pub type ANSIByteStrings<'a> = ANSIGenericStrings<'a, [u8]>;
-
-/// A function to construct an `ANSIByteStrings` instance.
-#[allow(non_snake_case)]
-pub fn ANSIByteStrings<'a>(arg: &'a [ANSIByteString<'a>]) -> ANSIByteStrings<'a> {
-    ANSIGenericStrings(arg)
-}
-
-
-// ---- paint functions ----
-
-impl Style {
-
-    /// Paints the given text with this colour, returning an ANSI string.
-    pub fn paint<'a, I, S: 'a + ToOwned + ?Sized>(self, input: I) -> ANSIGenericString<'a, S>
-    where I: Into<Cow<'a, S>>,
-          <S as ToOwned>::Owned: fmt::Debug {
-        ANSIGenericString {
-            string: input.into(),
-            style:  self,
-        }
-    }
-}
-
-
-impl Colour {
-
-    /// Paints the given text with this colour, returning an ANSI string.
-    /// This is a short-cut so you don’t have to use `Blue.normal()` just
-    /// to get blue text.
-    ///
-    /// ```
-    /// use ansi_term::Colour::Blue;
-    /// println!("{}", Blue.paint("da ba dee"));
-    /// ```
-    pub fn paint<'a, I, S: 'a + ToOwned + ?Sized>(self, input: I) -> ANSIGenericString<'a, S>
-    where I: Into<Cow<'a, S>>,
-          <S as ToOwned>::Owned: fmt::Debug {
-        ANSIGenericString {
-            string: input.into(),
-            style:  self.normal(),
-        }
-    }
-}
-
-
-// ---- writers for individual ANSI strings ----
-
-impl<'a> fmt::Display for ANSIString<'a> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        let w: &mut fmt::Write = f;
-        self.write_to_any(w)
-    }
-}
-
-impl<'a> ANSIByteString<'a> {
-    /// Write an `ANSIByteString` to an `io::Write`.  This writes the escape
-    /// sequences for the associated `Style` around the bytes.
-    pub fn write_to<W: io::Write>(&self, w: &mut W) -> io::Result<()> {
-        let w: &mut io::Write = w;
-        self.write_to_any(w)
-    }
-}
-
-impl<'a, S: 'a + ToOwned + ?Sized> ANSIGenericString<'a, S>
-where <S as ToOwned>::Owned: fmt::Debug, &'a S: AsRef<[u8]> {
-    fn write_to_any<W: AnyWrite<wstr=S> + ?Sized>(&self, w: &mut W) -> Result<(), W::Error> {
-        write!(w, "{}", self.style.prefix())?;
-        w.write_str(self.string.as_ref())?;
-        write!(w, "{}", self.style.suffix())
-    }
-}
-
-
-// ---- writers for combined ANSI strings ----
-
-impl<'a> fmt::Display for ANSIStrings<'a> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        let f: &mut fmt::Write = f;
-        self.write_to_any(f)
-    }
-}
-
-impl<'a> ANSIByteStrings<'a> {
-    /// Write `ANSIByteStrings` to an `io::Write`.  This writes the minimal
-    /// escape sequences for the associated `Style`s around each set of
-    /// bytes.
-    pub fn write_to<W: io::Write>(&self, w: &mut W) -> io::Result<()> {
-        let w: &mut io::Write = w;
-        self.write_to_any(w)
-    }
-}
-
-impl<'a, S: 'a + ToOwned + ?Sized> ANSIGenericStrings<'a, S>
-where <S as ToOwned>::Owned: fmt::Debug, &'a S: AsRef<[u8]> {
-    fn write_to_any<W: AnyWrite<wstr=S> + ?Sized>(&self, w: &mut W) -> Result<(), W::Error> {
-        use self::Difference::*;
-
-        let first = match self.0.first() {
-            None => return Ok(()),
-            Some(f) => f,
-        };
-
-        write!(w, "{}", first.style.prefix())?;
-        w.write_str(first.string.as_ref())?;
-
-        for window in self.0.windows(2) {
-            match Difference::between(&window[0].style, &window[1].style) {
-                ExtraStyles(style) => write!(w, "{}", style.prefix())?,
-                Reset              => write!(w, "{}{}", RESET, window[1].style.prefix())?,
-                NoDifference       => {/* Do nothing! */},
-            }
-
-            w.write_str(&window[1].string)?;
-        }
-
-        // Write the final reset string after all of the ANSIStrings have been
-        // written, *except* if the last one has no styles, because it would
-        // have already been written by this point.
-        if let Some(last) = self.0.last() {
-            if !last.style.is_plain() {
-                write!(w, "{}", RESET)?;
-            }
-        }
-
-        Ok(())
-    }
-}
-
-
-// ---- tests ----
-
-#[cfg(test)]
-mod tests {
-    pub use super::super::ANSIStrings;
-    pub use style::Style;
-    pub use style::Colour::*;
-
-    #[test]
-    fn no_control_codes_for_plain() {
-        let one = Style::default().paint("one");
-        let two = Style::default().paint("two");
-        let output = format!("{}", ANSIStrings( &[ one, two ] ));
-        assert_eq!(&*output, "onetwo");
-    }
-}
diff --git a/third_party/rust/ansi_term/src/lib.rs b/third_party/rust/ansi_term/src/lib.rs
deleted file mode 100644
index f2a676a1c5..0000000000
--- a/third_party/rust/ansi_term/src/lib.rs
+++ /dev/null
@@ -1,205 +0,0 @@
-//! This is a library for controlling colours and formatting, such as
-//! red bold text or blue underlined text, on ANSI terminals.
-//!
-//!
-//! ## Basic usage
-//!
-//! There are two main data structures in this crate that you need to be
-//! concerned with: `ANSIString` and `Style`. A `Style` holds stylistic
-//! information: colours, whether the text should be bold, or blinking, or
-//! whatever. There are also `Colour` variants that represent simple foreground
-//! colour styles. An `ANSIString` is a string paired with a `Style`.
-//!
-//! (Yes, it’s British English, but you won’t have to write “colour” very often.
-//! `Style` is used the majority of the time.)
-//!
-//! To format a string, call the `paint` method on a `Style` or a `Colour`,
-//! passing in the string you want to format as the argument. For example,
-//! here’s how to get some red text:
-//!
-//!     use ansi_term::Colour::Red;
-//!     println!("This is in red: {}", Red.paint("a red string"));
-//!
-//! It’s important to note that the `paint` method does *not* actually return a
-//! string with the ANSI control characters surrounding it. Instead, it returns
-//! an `ANSIString` value that has a `Display` implementation that, when
-//! formatted, returns the characters. This allows strings to be printed with a
-//! minimum of `String` allocations being performed behind the scenes.
-//!
-//! If you *do* want to get at the escape codes, then you can convert the
-//! `ANSIString` to a string as you would any other `Display` value:
-//!
-//!     use ansi_term::Colour::Red;
-//!     use std::string::ToString;
-//!     let red_string = Red.paint("a red string").to_string();
-//!
-//!
-//! ## Bold, underline, background, and other styles
-//!
-//! For anything more complex than plain foreground colour changes, you need to
-//! construct `Style` objects themselves, rather than beginning with a `Colour`.
-//! You can do this by chaining methods based on a new `Style`, created with
-//! `Style::new()`. Each method creates a new style that has that specific
-//! property set. For example:
-//!
-//!     use ansi_term::Style;
-//!     println!("How about some {} and {}?",
-//!              Style::new().bold().paint("bold"),
-//!              Style::new().underline().paint("underline"));
-//!
-//! For brevity, these methods have also been implemented for `Colour` values,
-//! so you can give your styles a foreground colour without having to begin with
-//! an empty `Style` value:
-//!
-//!     use ansi_term::Colour::{Blue, Yellow};
-//!     println!("Demonstrating {} and {}!",
-//!              Blue.bold().paint("blue bold"),
-//!              Yellow.underline().paint("yellow underline"));
-//!     println!("Yellow on blue: {}", Yellow.on(Blue).paint("wow!"));
-//!
-//! The complete list of styles you can use are: `bold`, `dimmed`, `italic`,
-//! `underline`, `blink`, `reverse`, `hidden`, `strikethrough`, and `on` for
-//! background colours.
-//!
-//! In some cases, you may find it easier to change the foreground on an
-//! existing `Style` rather than starting from the appropriate `Colour`.
-//! You can do this using the `fg` method:
-//!
-//!     use ansi_term::Style;
-//!     use ansi_term::Colour::{Blue, Cyan, Yellow};
-//!     println!("Yellow on blue: {}", Style::new().on(Blue).fg(Yellow).paint("yow!"));
-//!     println!("Also yellow on blue: {}", Cyan.on(Blue).fg(Yellow).paint("zow!"));
-//!
-//! Finally, you can turn a `Colour` into a `Style` with the `normal` method.
-//! This will produce the exact same `ANSIString` as if you just used the
-//! `paint` method on the `Colour` directly, but it’s useful in certain cases:
-//! for example, you may have a method that returns `Styles`, and need to
-//! represent both the “red bold” and “red, but not bold” styles with values of
-//! the same type. The `Style` struct also has a `Default` implementation if you
-//! want to have a style with *nothing* set.
-//!
-//!     use ansi_term::Style;
-//!     use ansi_term::Colour::Red;
-//!     Red.normal().paint("yet another red string");
-//!     Style::default().paint("a completely regular string");
-//!
-//!
-//! ## Extended colours
-//!
-//! You can access the extended range of 256 colours by using the `Fixed` colour
-//! variant, which takes an argument of the colour number to use. This can be
-//! included wherever you would use a `Colour`:
-//!
-//!     use ansi_term::Colour::Fixed;
-//!     Fixed(134).paint("A sort of light purple");
-//!     Fixed(221).on(Fixed(124)).paint("Mustard in the ketchup");
-//!
-//! The first sixteen of these values are the same as the normal and bold
-//! standard colour variants. There’s nothing stopping you from using these as
-//! `Fixed` colours instead, but there’s nothing to be gained by doing so
-//! either.
-//!
-//! You can also access full 24-bit color by using the `RGB` colour variant,
-//! which takes separate `u8` arguments for red, green, and blue:
-//!
-//!     use ansi_term::Colour::RGB;
-//!     RGB(70, 130, 180).paint("Steel blue");
-//!
-//! ## Combining successive coloured strings
-//!
-//! The benefit of writing ANSI escape codes to the terminal is that they
-//! *stack*: you do not need to end every coloured string with a reset code if
-//! the text that follows it is of a similar style. For example, if you want to
-//! have some blue text followed by some blue bold text, it’s possible to send
-//! the ANSI code for blue, followed by the ANSI code for bold, and finishing
-//! with a reset code without having to have an extra one between the two
-//! strings.
-//!
-//! This crate can optimise the ANSI codes that get printed in situations like
-//! this, making life easier for your terminal renderer. The `ANSIStrings`
-//! struct takes a slice of several `ANSIString` values, and will iterate over
-//! each of them, printing only the codes for the styles that need to be updated
-//! as part of its formatting routine.
-//!
-//! The following code snippet uses this to enclose a binary number displayed in
-//! red bold text inside some red, but not bold, brackets:
-//!
-//!     use ansi_term::Colour::Red;
-//!     use ansi_term::{ANSIString, ANSIStrings};
-//!     let some_value = format!("{:b}", 42);
-//!     let strings: &[ANSIString<'static>] = &[
-//!         Red.paint("["),
-//!         Red.bold().paint(some_value),
-//!         Red.paint("]"),
-//!     ];
-//!     println!("Value: {}", ANSIStrings(strings));
-//!
-//! There are several things to note here. Firstly, the `paint` method can take
-//! *either* an owned `String` or a borrowed `&str`. Internally, an `ANSIString`
-//! holds a copy-on-write (`Cow`) string value to deal with both owned and
-//! borrowed strings at the same time. This is used here to display a `String`,
-//! the result of the `format!` call, using the same mechanism as some
-//! statically-available `&str` slices. Secondly, that the `ANSIStrings` value
-//! works in the same way as its singular counterpart, with a `Display`
-//! implementation that only performs the formatting when required.
-//!
-//! ## Byte strings
-//!
-//! This library also supports formatting `[u8]` byte strings; this supports
-//! applications working with text in an unknown encoding.  `Style` and
-//! `Color` support painting `[u8]` values, resulting in an `ANSIByteString`.
-//! This type does not implement `Display`, as it may not contain UTF-8, but
-//! it does provide a method `write_to` to write the result to any
-//! `io::Write`:
-//!
-//!     use ansi_term::Colour::Green;
-//!     Green.paint("user data".as_bytes()).write_to(&mut std::io::stdout()).unwrap();
-//!
-//! Similarly, the type `ANSIByteStrings` supports writing a list of
-//! `ANSIByteString` values with minimal escape sequences:
-//!
-//!     use ansi_term::Colour::Green;
-//!     use ansi_term::ANSIByteStrings;
-//!     ANSIByteStrings(&[
-//!         Green.paint("user data 1\n".as_bytes()),
-//!         Green.bold().paint("user data 2\n".as_bytes()),
-//!     ]).write_to(&mut std::io::stdout()).unwrap();
-
-
-#![crate_name = "ansi_term"]
-#![crate_type = "rlib"]
-#![crate_type = "dylib"]
-
-#![warn(missing_copy_implementations)]
-#![warn(missing_docs)]
-#![warn(trivial_casts, trivial_numeric_casts)]
-#![warn(unused_extern_crates, unused_qualifications)]
-
-#[cfg(target_os="windows")]
-extern crate winapi;
-
-mod ansi;
-pub use ansi::{Prefix, Infix, Suffix};
-
-mod style;
-pub use style::{Colour, Style};
-
-/// Color is a type alias for Colour for those who can't be bothered.
-pub use Colour as Color;
-
-// I'm not beyond calling Colour Colour, rather than Color, but I did
-// purposefully name this crate 'ansi-term' so people wouldn't get
-// confused when they tried to install it.
-//
-// Only *after* they'd installed it.
-
-mod difference;
-mod display;
-pub use display::*;
-
-mod write;
-
-mod windows;
-pub use windows::*;
-
-mod debug;
diff --git a/third_party/rust/ansi_term/src/style.rs b/third_party/rust/ansi_term/src/style.rs
deleted file mode 100644
index b9fb52326a..0000000000
--- a/third_party/rust/ansi_term/src/style.rs
+++ /dev/null
@@ -1,259 +0,0 @@
-/// A style is a collection of properties that can format a string
-/// using ANSI escape codes.
-#[derive(PartialEq, Clone, Copy)]
-pub struct Style {
-
-    /// The style's foreground colour, if it has one.
-    pub foreground: Option<Colour>,
-
-    /// The style's background colour, if it has one.
-    pub background: Option<Colour>,
-
-    /// Whether this style is bold.
-    pub is_bold: bool,
-
-    /// Whether this style is dimmed.
-    pub is_dimmed: bool,
-
-    /// Whether this style is italic.
-    pub is_italic: bool,
-
-    /// Whether this style is underlined.
-    pub is_underline: bool,
-
-    /// Whether this style is blinking.
-    pub is_blink: bool,
-
-    /// Whether this style has reverse colours.
-    pub is_reverse: bool,
-
-    /// Whether this style is hidden.
-    pub is_hidden: bool,
-
-    /// Whether this style is struckthrough.
-    pub is_strikethrough: bool
-}
-
-impl Style {
-    /// Creates a new Style with no differences.
-    pub fn new() -> Style {
-        Style::default()
-    }
-
-    /// Returns a `Style` with the bold property set.
-    pub fn bold(&self) -> Style {
-        Style { is_bold: true, .. *self }
-    }
-
-    /// Returns a `Style` with the dimmed property set.
-    pub fn dimmed(&self) -> Style {
-        Style { is_dimmed: true, .. *self }
-    }
-
-    /// Returns a `Style` with the italic property set.
-    pub fn italic(&self) -> Style {
-        Style { is_italic: true, .. *self }
-    }
-
-    /// Returns a `Style` with the underline property set.
-    pub fn underline(&self) -> Style {
-        Style { is_underline: true, .. *self }
-    }
-
-    /// Returns a `Style` with the blink property set.
-    pub fn blink(&self) -> Style {
-        Style { is_blink: true, .. *self }
-    }
-
-    /// Returns a `Style` with the reverse property set.
-    pub fn reverse(&self) -> Style {
-        Style { is_reverse: true, .. *self }
-    }
-
-    /// Returns a `Style` with the hidden property set.
-    pub fn hidden(&self) -> Style {
-        Style { is_hidden: true, .. *self }
-    }
-
-    /// Returns a `Style` with the hidden property set.
-    pub fn strikethrough(&self) -> Style {
-        Style { is_strikethrough: true, .. *self }
-    }
-
-    /// Returns a `Style` with the foreground colour property set.
-    pub fn fg(&self, foreground: Colour) -> Style {
-        Style { foreground: Some(foreground), .. *self }
-    }
-
-    /// Returns a `Style` with the background colour property set.
-    pub fn on(&self, background: Colour) -> Style {
-        Style { background: Some(background), .. *self }
-    }
-
-    /// Return true if this `Style` has no actual styles, and can be written
-    /// without any control characters.
-    pub fn is_plain(self) -> bool {
-        self == Style::default()
-    }
-}
-
-impl Default for Style {
-
-    /// Returns a style with *no* properties set. Formatting text using this
-    /// style returns the exact same text.
-    ///
-    /// ```
-    /// use ansi_term::Style;
-    /// assert_eq!(None,  Style::default().foreground);
-    /// assert_eq!(None,  Style::default().background);
-    /// assert_eq!(false, Style::default().is_bold);
-    /// assert_eq!("txt", Style::default().paint("txt").to_string());
-    /// ```
-    fn default() -> Style {
-        Style {
-            foreground: None,
-            background: None,
-            is_bold: false,
-            is_dimmed: false,
-            is_italic: false,
-            is_underline: false,
-            is_blink: false,
-            is_reverse: false,
-            is_hidden: false,
-            is_strikethrough: false,
-        }
-    }
-}
-
-
-// ---- colours ----
-
-/// A colour is one specific type of ANSI escape code, and can refer
-/// to either the foreground or background colour.
-///
-/// These use the standard numeric sequences.
-/// See <http://invisible-island.net/xterm/ctlseqs/ctlseqs.html>
-#[derive(PartialEq, Clone, Copy, Debug)]
-pub enum Colour {
-
-    /// Colour #0 (foreground code `30`, background code `40`).
-    ///
-    /// This is not necessarily the background colour, and using it as one may
-    /// render the text hard to read on terminals with dark backgrounds.
-    Black,
-
-    /// Colour #1 (foreground code `31`, background code `41`).
-    Red,
-
-    /// Colour #2 (foreground code `32`, background code `42`).
-    Green,
-
-    /// Colour #3 (foreground code `33`, background code `43`).
-    Yellow,
-
-    /// Colour #4 (foreground code `34`, background code `44`).
-    Blue,
-
-    /// Colour #5 (foreground code `35`, background code `45`).
-    Purple,
-
-    /// Colour #6 (foreground code `36`, background code `46`).
-    Cyan,
-
-    /// Colour #7 (foreground code `37`, background code `47`).
-    ///
-    /// As above, this is not necessarily the foreground colour, and may be
-    /// hard to read on terminals with light backgrounds.
-    White,
-
-    /// A colour number from 0 to 255, for use in 256-colour terminal
-    /// environments.
-    ///
-    /// - Colours 0 to 7 are the `Black` to `White` variants respectively.
-    ///   These colours can usually be changed in the terminal emulator.
-    /// - Colours 8 to 15 are brighter versions of the eight colours above.
-    ///   These can also usually be changed in the terminal emulator, or it
-    ///   could be configured to use the original colours and show the text in
-    ///   bold instead. It varies depending on the program.
-    /// - Colours 16 to 231 contain several palettes of bright colours,
-    ///   arranged in six squares measuring six by six each.
-    /// - Colours 232 to 255 are shades of grey from black to white.
-    ///
-    /// It might make more sense to look at a [colour chart][cc].
-    ///
-    /// [cc]: https://upload.wikimedia.org/wikipedia/en/1/15/Xterm_256color_chart.svg
-    Fixed(u8),
-
-    /// A 24-bit RGB color, as specified by ISO-8613-3.
-    RGB(u8, u8, u8),
-}
-
-
-impl Colour {
-    /// Return a `Style` with the foreground colour set to this colour.
-    pub fn normal(self) -> Style {
-        Style { foreground: Some(self), .. Style::default() }
-    }
-
-    /// Returns a `Style` with the bold property set.
-    pub fn bold(self) -> Style {
-        Style { foreground: Some(self), is_bold: true, .. Style::default() }
-    }
-
-    /// Returns a `Style` with the dimmed property set.
-    pub fn dimmed(self) -> Style {
-        Style { foreground: Some(self), is_dimmed: true, .. Style::default() }
-    }
-
-    /// Returns a `Style` with the italic property set.
-    pub fn italic(self) -> Style {
-        Style { foreground: Some(self), is_italic: true, .. Style::default() }
-    }
-
-    /// Returns a `Style` with the underline property set.
-    pub fn underline(self) -> Style {
-        Style { foreground: Some(self), is_underline: true, .. Style::default() }
-    }
-
-    /// Returns a `Style` with the blink property set.
-    pub fn blink(self) -> Style {
-        Style { foreground: Some(self), is_blink: true, .. Style::default() }
-    }
-
-    /// Returns a `Style` with the reverse property set.
-    pub fn reverse(self) -> Style {
-        Style { foreground: Some(self), is_reverse: true, .. Style::default() }
-    }
-
-    /// Returns a `Style` with the hidden property set.
-    pub fn hidden(self) -> Style {
-        Style { foreground: Some(self), is_hidden: true, .. Style::default() }
-    }
-
-    /// Returns a `Style` with the strikethrough property set.
-    pub fn strikethrough(self) -> Style {
-        Style { foreground: Some(self), is_strikethrough: true, .. Style::default() }
-    }
-
-    /// Returns a `Style` with the background colour property set.
-    pub fn on(self, background: Colour) -> Style {
-        Style { foreground: Some(self), background: Some(background), .. Style::default() }
-    }
-}
-
-impl From<Colour> for Style {
-
-    /// You can turn a `Colour` into a `Style` with the foreground colour set
-    /// with the `From` trait.
-    ///
-    /// ```
-    /// use ansi_term::{Style, Colour};
-    /// let green_foreground = Style::default().fg(Colour::Green);
-    /// assert_eq!(green_foreground, Colour::Green.normal());
-    /// assert_eq!(green_foreground, Colour::Green.into());
-    /// assert_eq!(green_foreground, Style::from(Colour::Green));
-    /// ```
-    fn from(colour: Colour) -> Style {
-        colour.normal()
-    }
-}
diff --git a/third_party/rust/ansi_term/src/windows.rs b/third_party/rust/ansi_term/src/windows.rs
deleted file mode 100644
index ff6fa683d8..0000000000
--- a/third_party/rust/ansi_term/src/windows.rs
+++ /dev/null
@@ -1,40 +0,0 @@
-/// Enables ANSI code support on Windows 10.
-///
-/// This uses Windows API calls to alter the properties of the console that
-/// the program is running in.
-///
-/// https://msdn.microsoft.com/en-us/library/windows/desktop/mt638032(v=vs.85).aspx
-///
-/// Returns a `Result` with the Windows error code if unsuccessful.
-#[cfg(windows)]
-pub fn enable_ansi_support() -> Result<(), u32> {
-    use winapi::um::processenv::GetStdHandle;
-    use winapi::um::errhandlingapi::GetLastError;
-    use winapi::um::consoleapi::{GetConsoleMode, SetConsoleMode};
-
-    const STD_OUT_HANDLE: u32 = -11i32 as u32;
-    const ENABLE_VIRTUAL_TERMINAL_PROCESSING: u32 = 0x0004;
-
-    unsafe {
-        // https://docs.microsoft.com/en-us/windows/console/getstdhandle
-        let std_out_handle = GetStdHandle(STD_OUT_HANDLE);
-        let error_code = GetLastError();
-        if error_code != 0 { return Err(error_code); }
-        
-        // https://docs.microsoft.com/en-us/windows/console/getconsolemode
-        let mut console_mode: u32 = 0;
-        GetConsoleMode(std_out_handle, &mut console_mode);
-        let error_code = GetLastError();
-        if error_code != 0 { return Err(error_code); }
-
-        // VT processing not already enabled?
-        if console_mode & ENABLE_VIRTUAL_TERMINAL_PROCESSING == 0 {
-            // https://docs.microsoft.com/en-us/windows/console/setconsolemode
-            SetConsoleMode(std_out_handle, console_mode | ENABLE_VIRTUAL_TERMINAL_PROCESSING);
-            let error_code = GetLastError();
-            if error_code != 0 { return Err(error_code); }
-        }
-    }
-
-    return Ok(());
-}
diff --git a/third_party/rust/ansi_term/src/write.rs b/third_party/rust/ansi_term/src/write.rs
deleted file mode 100644
index bb146ac156..0000000000
--- a/third_party/rust/ansi_term/src/write.rs
+++ /dev/null
@@ -1,40 +0,0 @@
-use std::fmt;
-use std::io;
-
-
-pub trait AnyWrite {
-    type wstr: ?Sized;
-    type Error;
-
-    fn write_fmt(&mut self, fmt: fmt::Arguments) -> Result<(), Self::Error>;
-
-    fn write_str(&mut self, s: &Self::wstr) -> Result<(), Self::Error>;
-}
-
-
-impl<'a> AnyWrite for fmt::Write + 'a {
-    type wstr = str;
-    type Error = fmt::Error;
-
-    fn write_fmt(&mut self, fmt: fmt::Arguments) -> Result<(), Self::Error> {
-        fmt::Write::write_fmt(self, fmt)
-    }
-
-    fn write_str(&mut self, s: &Self::wstr) -> Result<(), Self::Error> {
-        fmt::Write::write_str(self, s)
-    }
-}
-
-
-impl<'a> AnyWrite for io::Write + 'a {
-    type wstr = [u8];
-    type Error = io::Error;
-
-    fn write_fmt(&mut self, fmt: fmt::Arguments) -> Result<(), Self::Error> {
-        io::Write::write_fmt(self, fmt)
-    }
-
-    fn write_str(&mut self, s: &Self::wstr) -> Result<(), Self::Error> {
-        io::Write::write_all(self, s)
-    }
-}
diff --git a/third_party/rust/binjs_meta/.cargo-checksum.json b/third_party/rust/binjs_meta/.cargo-checksum.json
deleted file mode 100644
index bcf84681a5..0000000000
--- a/third_party/rust/binjs_meta/.cargo-checksum.json
+++ /dev/null
@@ -1 +0,0 @@
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diff --git a/third_party/rust/binjs_meta/Cargo.lock b/third_party/rust/binjs_meta/Cargo.lock
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-"checksum humantime 1.3.0 (registry+https://github.com/rust-lang/crates.io-index)" = "df004cfca50ef23c36850aaaa59ad52cc70d0e90243c3c7737a4dd32dc7a3c4f"
-"checksum itertools 0.8.2 (registry+https://github.com/rust-lang/crates.io-index)" = "f56a2d0bc861f9165be4eb3442afd3c236d8a98afd426f65d92324ae1091a484"
-"checksum lazy_static 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)" = "c8f31047daa365f19be14b47c29df4f7c3b581832407daabe6ae77397619237d"
-"checksum libc 0.2.36 (registry+https://github.com/rust-lang/crates.io-index)" = "1e5d97d6708edaa407429faa671b942dc0f2727222fb6b6539bf1db936e4b121"
-"checksum linked-hash-map 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)" = "70fb39025bc7cdd76305867c4eccf2f2dcf6e9a57f5b21a93e1c2d86cd03ec9e"
-"checksum log 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)" = "89f010e843f2b1a31dbd316b3b8d443758bc634bed37aabade59c686d644e0a2"
-"checksum memchr 2.0.1 (registry+https://github.com/rust-lang/crates.io-index)" = "796fba70e76612589ed2ce7f45282f5af869e0fdd7cc6199fa1aa1f1d591ba9d"
-"checksum nom 5.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "0b471253da97532da4b61552249c521e01e736071f71c1a4f7ebbfbf0a06aad6"
-"checksum quick-error 1.2.3 (registry+https://github.com/rust-lang/crates.io-index)" = "a1d01941d82fa2ab50be1e79e6714289dd7cde78eba4c074bc5a4374f650dfe0"
-"checksum redox_syscall 0.1.37 (registry+https://github.com/rust-lang/crates.io-index)" = "0d92eecebad22b767915e4d529f89f28ee96dbbf5a4810d2b844373f136417fd"
-"checksum redox_termios 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "7e891cfe48e9100a70a3b6eb652fef28920c117d366339687bd5576160db0f76"
-"checksum regex 1.0.3 (registry+https://github.com/rust-lang/crates.io-index)" = "3d8c9f33201f46669484bacc312b00e7541bed6aaf296dffe2bb4e0ac6b8ce2a"
-"checksum regex-syntax 0.6.16 (registry+https://github.com/rust-lang/crates.io-index)" = "1132f845907680735a84409c3bebc64d1364a5683ffbce899550cd09d5eaefc1"
-"checksum strsim 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)" = "bb4f380125926a99e52bc279241539c018323fab05ad6368b56f93d9369ff550"
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-"checksum vec_map 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)" = "887b5b631c2ad01628bbbaa7dd4c869f80d3186688f8d0b6f58774fbe324988c"
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-"checksum yaml-rust 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "57ab38ee1a4a266ed033496cf9af1828d8d6e6c1cfa5f643a2809effcae4d628"
diff --git a/third_party/rust/binjs_meta/Cargo.toml b/third_party/rust/binjs_meta/Cargo.toml
deleted file mode 100644
index 2d0f3464af..0000000000
--- a/third_party/rust/binjs_meta/Cargo.toml
+++ /dev/null
@@ -1,46 +0,0 @@
-# THIS FILE IS AUTOMATICALLY GENERATED BY CARGO
-#
-# When uploading crates to the registry Cargo will automatically
-# "normalize" Cargo.toml files for maximal compatibility
-# with all versions of Cargo and also rewrite `path` dependencies
-# to registry (e.g., crates.io) dependencies
-#
-# If you believe there's an error in this file please file an
-# issue against the rust-lang/cargo repository. If you're
-# editing this file be aware that the upstream Cargo.toml
-# will likely look very different (and much more reasonable)
-
-[package]
-name = "binjs_meta"
-version = "0.5.4"
-authors = ["David Teller <D.O.Teller@gmail.com>"]
-description = "Part of binjs-ref. Tools for manipulating grammars. You probably do not want to use this crate directly unless you're writing an encoder, decoder or parser generator for binjs."
-homepage = "https://binast.github.io/ecmascript-binary-ast/"
-readme = "README.md"
-keywords = ["javascript", "js", "binjs", "ast"]
-categories = ["compression", "parsing", "web-programming"]
-license = "MIT"
-repository = "https://github.com/binast/binjs-ref"
-[dependencies.Inflector]
-version = "^0.11.4"
-default-features = false
-
-[dependencies.itertools]
-version = "^0.8"
-
-[dependencies.log]
-version = "^0.4"
-
-[dependencies.weedle]
-version = "0.11"
-[dev-dependencies.clap]
-version = "^2.0"
-
-[dev-dependencies.env_logger]
-version = "^0.6"
-
-[dev-dependencies.yaml-rust]
-version = "^0.4"
-[badges.travis-ci]
-branch = "master"
-repository = "https://github.com/binast/binjs-ref"
diff --git a/third_party/rust/binjs_meta/README.md b/third_party/rust/binjs_meta/README.md
deleted file mode 100644
index 2358031280..0000000000
--- a/third_party/rust/binjs_meta/README.md
+++ /dev/null
@@ -1,7 +0,0 @@
-# About
-
-This crate contains the tools used to manipulate the abstract syntax of JavaScript,
-i.e. generate parsers, encoders, etc from a specification of ASTs of the language.
-
-Actual tools to manipulate ASTs for a specific version of JavaScript are
-in dependent crates.
diff --git a/third_party/rust/binjs_meta/examples/generate_spidermonkey.rs b/third_party/rust/binjs_meta/examples/generate_spidermonkey.rs
deleted file mode 100644
index faddba9dac..0000000000
--- a/third_party/rust/binjs_meta/examples/generate_spidermonkey.rs
+++ /dev/null
@@ -1,1668 +0,0 @@
-// !!!! WARNING !!!!
-// This is a snapshot of the code generator for SpiderMonkey, for demonstrating
-// how to use binjs_meta crate in order to generate a parser.
-//
-// The latest version of this code is available as
-// js/src/frontend/binsource/src/main.rs in the following repository:
-//   https://hg.mozilla.org/mozilla-central/
-
-extern crate binjs_meta;
-extern crate clap;
-extern crate env_logger;
-extern crate itertools;
-#[macro_use]
-extern crate log;
-extern crate yaml_rust;
-
-use binjs_meta::export::{ToWebidl, TypeDeanonymizer, TypeName};
-use binjs_meta::import::Importer;
-use binjs_meta::spec::*;
-use binjs_meta::util::{Reindentable, ToCases, ToStr};
-
-use std::collections::{HashMap, HashSet};
-use std::fs;
-
-use clap::{App, Arg};
-
-use itertools::Itertools;
-
-/// Rules for generating the code for parsing a single field
-/// of a node.
-///
-/// Extracted from the yaml file.
-#[derive(Clone, Default)]
-struct FieldRules {
-    /// Declaring the variable to hold the contents of that field.
-    declare: Option<String>,
-
-    /// Replace the declaration and assignation.
-    replace: Option<String>,
-
-    /// Things to add before the field, typically for checking invariants.
-    before_field: Option<String>,
-
-    /// Things to add after the field, typically for checking invariants.
-    after_field: Option<String>,
-
-    /// Things to add before the field, as part of a block, typically for
-    /// putting guard values on the stack.
-    block_before_field: Option<String>,
-
-    /// Things to add before the field, as part of a block, typically for
-    /// cleanup.
-    block_after_field: Option<String>,
-}
-
-/// Rules for generating the code for parsing a full node
-/// of a node.
-///
-/// Extracted from the yaml file.
-#[derive(Clone, Default)]
-struct NodeRules {
-    /// This node inherits from another node.
-    inherits: Option<NodeName>,
-
-    /// Override the result type for the method.
-    type_ok: Option<String>,
-
-    /// Stuff to add at start.
-    init: Option<String>,
-
-    /// How to append to a list. Used only for lists.
-    append: Option<String>,
-
-    /// Custom per-field treatment. Used only for interfaces.
-    by_field: HashMap<FieldName, FieldRules>,
-
-    /// How to build the result, eventually.
-    build_result: Option<String>,
-}
-
-/// Rules for generating entire files.
-///
-/// Extracted from the yaml file.
-#[derive(Default)]
-struct GlobalRules {
-    /// Header to add at the start of the .cpp file.
-    cpp_header: Option<String>,
-
-    /// Header to add at the end of the .cpp file.
-    cpp_footer: Option<String>,
-
-    /// Header to add at the start of the .hpp file
-    /// defining the class data/methods.
-    hpp_class_header: Option<String>,
-
-    /// Header to add at the start of the .hpp file.
-    /// defining the tokens.
-    hpp_tokens_header: Option<String>,
-
-    /// Footer to add at the start of the .hpp file.
-    /// defining the tokens.
-    hpp_tokens_footer: Option<String>,
-
-    /// Documentation for the `BinKind` class enum.
-    hpp_tokens_kind_doc: Option<String>,
-
-    /// Documentation for the `BinField` class enum.
-    hpp_tokens_field_doc: Option<String>,
-
-    /// Documentation for the `BinVariant` class enum.
-    hpp_tokens_variants_doc: Option<String>,
-
-    /// Per-node rules.
-    per_node: HashMap<NodeName, NodeRules>,
-}
-impl GlobalRules {
-    fn new(syntax: &Spec, yaml: &yaml_rust::yaml::Yaml) -> Self {
-        let rules = yaml.as_hash().expect("Rules are not a dictionary");
-
-        let mut cpp_header = None;
-        let mut cpp_footer = None;
-        let mut hpp_class_header = None;
-        let mut hpp_tokens_header = None;
-        let mut hpp_tokens_footer = None;
-        let mut hpp_tokens_kind_doc = None;
-        let mut hpp_tokens_field_doc = None;
-        let mut hpp_tokens_variants_doc = None;
-        let mut per_node = HashMap::new();
-
-        for (node_key, node_entries) in rules.iter() {
-            let node_key = node_key
-                .as_str()
-                .expect("Could not convert node_key to string");
-
-            match node_key {
-                "cpp" => {
-                    update_rule(&mut cpp_header, &node_entries["header"])
-                        .unwrap_or_else(|_| panic!("Rule cpp.header must be a string"));
-                    update_rule(&mut cpp_footer, &node_entries["footer"])
-                        .unwrap_or_else(|_| panic!("Rule cpp.footer must be a string"));
-                    continue;
-                }
-                "hpp" => {
-                    update_rule(&mut hpp_class_header, &node_entries["class"]["header"])
-                        .unwrap_or_else(|_| panic!("Rule hpp.class.header must be a string"));
-                    update_rule(&mut hpp_tokens_header, &node_entries["tokens"]["header"])
-                        .unwrap_or_else(|_| panic!("Rule hpp.tokens.header must be a string"));
-                    update_rule(&mut hpp_tokens_footer, &node_entries["tokens"]["footer"])
-                        .unwrap_or_else(|_| panic!("Rule hpp.tokens.footer must be a string"));
-                    update_rule(
-                        &mut hpp_tokens_kind_doc,
-                        &node_entries["tokens"]["kind"]["doc"],
-                    )
-                    .unwrap_or_else(|_| panic!("Rule hpp.tokens.kind.doc must be a string"));
-                    update_rule(
-                        &mut hpp_tokens_field_doc,
-                        &node_entries["tokens"]["field"]["doc"],
-                    )
-                    .unwrap_or_else(|_| panic!("Rule hpp.tokens.field.doc must be a string"));
-                    update_rule(
-                        &mut hpp_tokens_variants_doc,
-                        &node_entries["tokens"]["variants"]["doc"],
-                    )
-                    .unwrap_or_else(|_| panic!("Rule hpp.tokens.variants.doc must be a string"));
-                    continue;
-                }
-                _ => {}
-            }
-
-            let node_name = syntax
-                .get_node_name(&node_key)
-                .unwrap_or_else(|| panic!("Unknown node name {}", node_key));
-
-            let hash = node_entries
-                .as_hash()
-                .unwrap_or_else(|| panic!("Node {} isn't a dictionary"));
-
-            let mut node_rule = NodeRules::default();
-            for (node_item_key, node_item_entry) in hash {
-                let as_string = node_item_key
-                    .as_str()
-                    .unwrap_or_else(|| panic!("Keys for rule {} must be strings", node_key));
-                match as_string {
-                    "inherits" => {
-                        let name = node_item_entry.as_str().unwrap_or_else(|| {
-                            panic!("Rule {}.{} must be a string", node_key, as_string)
-                        });
-                        let inherits = syntax
-                            .get_node_name(name)
-                            .unwrap_or_else(|| panic!("Unknown node name {}", node_key));
-                        node_rule.inherits = Some(inherits).cloned();
-                    }
-                    "init" => {
-                        update_rule(&mut node_rule.init, node_item_entry).unwrap_or_else(|()| {
-                            panic!("Rule {}.{} must be a string", node_key, as_string)
-                        });
-                    }
-                    "build" => {
-                        update_rule(&mut node_rule.build_result, node_item_entry).unwrap_or_else(
-                            |()| panic!("Rule {}.{} must be a string", node_key, as_string),
-                        );
-                    }
-                    "append" => {
-                        update_rule(&mut node_rule.append, node_item_entry).unwrap_or_else(|()| {
-                            panic!("Rule {}.{} must be a string", node_key, as_string)
-                        });
-                    }
-                    "type-ok" => {
-                        update_rule(&mut node_rule.type_ok, node_item_entry).unwrap_or_else(|()| {
-                            panic!("Rule {}.{} must be a string", node_key, as_string)
-                        });
-                    }
-                    "fields" => {
-                        let fields = node_item_entry.as_hash().unwrap_or_else(|| {
-                            panic!(
-                                "Rule {}.fields must be a hash, got {:?}",
-                                node_key, node_entries["fields"]
-                            )
-                        });
-                        for (field_key, field_entry) in fields {
-                            let field_key = field_key
-                                .as_str()
-                                .unwrap_or_else(|| {
-                                    panic!(
-                                        "In rule {}, field entries must be field names",
-                                        node_key
-                                    )
-                                })
-                                .to_string();
-                            let field_name =
-                                syntax.get_field_name(&field_key).unwrap_or_else(|| {
-                                    panic!("In rule {}, can't find field {}", node_key, field_key)
-                                });
-
-                            let mut field_rule = FieldRules::default();
-                            for (field_config_key, field_config_entry) in
-                                field_entry.as_hash().unwrap_or_else(|| {
-                                    panic!("Rule {}.fields.{} must be a hash", node_key, field_key)
-                                })
-                            {
-                                let field_config_key = field_config_key
-                                    .as_str()
-                                    .expect("Expected a string as a key");
-                                match field_config_key {
-                                    "block" => {
-                                        update_rule(
-                                            &mut field_rule.declare,
-                                            &field_config_entry["declare"],
-                                        )
-                                        .unwrap_or_else(
-                                            |()| {
-                                                panic!(
-                                                    "Rule {}.fields.{}.{}.{} must be a string",
-                                                    node_key,
-                                                    field_key,
-                                                    field_config_key,
-                                                    "declare"
-                                                )
-                                            },
-                                        );
-
-                                        update_rule(
-                                            &mut field_rule.replace,
-                                            &field_config_entry["replace"],
-                                        )
-                                        .unwrap_or_else(
-                                            |()| {
-                                                panic!(
-                                                    "Rule {}.fields.{}.{}.{} must be a string",
-                                                    node_key,
-                                                    field_key,
-                                                    field_config_key,
-                                                    "replace"
-                                                )
-                                            },
-                                        );
-
-                                        update_rule(
-                                            &mut field_rule.block_before_field,
-                                            &field_config_entry["before"],
-                                        )
-                                        .unwrap_or_else(
-                                            |()| {
-                                                panic!(
-                                                    "Rule {}.fields.{}.{}.{} must be a string",
-                                                    node_key, field_key, field_config_key, "before"
-                                                )
-                                            },
-                                        );
-
-                                        update_rule(
-                                            &mut field_rule.block_after_field,
-                                            &field_config_entry["after"],
-                                        )
-                                        .unwrap_or_else(
-                                            |()| {
-                                                panic!(
-                                                    "Rule {}.fields.{}.{}.{} must be a string",
-                                                    node_key, field_key, field_config_key, "after"
-                                                )
-                                            },
-                                        );
-                                    }
-                                    "before" => {
-                                        update_rule(
-                                            &mut field_rule.before_field,
-                                            &field_config_entry,
-                                        )
-                                        .unwrap_or_else(
-                                            |()| {
-                                                panic!(
-                                                    "Rule {}.fields.{}.{} must be a string",
-                                                    node_key, field_key, field_config_key
-                                                )
-                                            },
-                                        );
-                                    }
-                                    "after" => {
-                                        update_rule(
-                                            &mut field_rule.after_field,
-                                            &field_config_entry,
-                                        )
-                                        .unwrap_or_else(
-                                            |()| {
-                                                panic!(
-                                                    "Rule {}.fields.{}.{} must be a string",
-                                                    node_key, field_key, field_config_key
-                                                )
-                                            },
-                                        );
-                                    }
-                                    _ => panic!(
-                                        "Unexpected {}.fields.{}.{}",
-                                        node_key, field_key, field_config_key
-                                    ),
-                                }
-                            }
-                            node_rule.by_field.insert(field_name.clone(), field_rule);
-                        }
-                    }
-                    _ => panic!("Unexpected node_item_key {}.{}", node_key, as_string),
-                }
-            }
-
-            per_node.insert(node_name.clone(), node_rule);
-        }
-
-        Self {
-            cpp_header,
-            cpp_footer,
-            hpp_class_header,
-            hpp_tokens_header,
-            hpp_tokens_footer,
-            hpp_tokens_kind_doc,
-            hpp_tokens_field_doc,
-            hpp_tokens_variants_doc,
-            per_node,
-        }
-    }
-    fn get(&self, name: &NodeName) -> NodeRules {
-        let mut rules = self.per_node.get(name).cloned().unwrap_or_default();
-        if let Some(ref parent) = rules.inherits {
-            let NodeRules {
-                inherits: _,
-                type_ok,
-                init,
-                append,
-                by_field,
-                build_result,
-            } = self.get(parent);
-            if rules.type_ok.is_none() {
-                rules.type_ok = type_ok;
-            }
-            if rules.init.is_none() {
-                rules.init = init;
-            }
-            if rules.append.is_none() {
-                rules.append = append;
-            }
-            if rules.build_result.is_none() {
-                rules.build_result = build_result;
-            }
-            for (key, value) in by_field {
-                rules.by_field.entry(key).or_insert(value);
-            }
-        }
-        rules
-    }
-}
-
-/// The inforamtion used to generate a list parser.
-struct ListParserData {
-    /// Name of the node.
-    name: NodeName,
-
-    /// If `true`, supports empty lists.
-    supports_empty: bool,
-
-    /// Name of the elements in the list.
-    elements: NodeName,
-}
-
-/// The inforamtion used to generate a parser for an optional data structure.
-struct OptionParserData {
-    /// Name of the node.
-    name: NodeName,
-
-    /// Name of the element that may be contained.
-    elements: NodeName,
-}
-
-/// The actual exporter.
-struct CPPExporter {
-    /// The syntax to export.
-    syntax: Spec,
-
-    /// Rules, as specified in yaml.
-    rules: GlobalRules,
-
-    /// All parsers of lists.
-    list_parsers_to_generate: Vec<ListParserData>,
-
-    /// All parsers of options.
-    option_parsers_to_generate: Vec<OptionParserData>,
-
-    /// A mapping from symbol (e.g. `+`, `-`, `instanceof`, ...) to the
-    /// name of the symbol as part of `enum class BinVariant`
-    /// (e.g. `UnaryOperatorDelete`).
-    variants_by_symbol: HashMap<String, String>,
-}
-
-impl CPPExporter {
-    fn new(syntax: Spec, rules: GlobalRules) -> Self {
-        let mut list_parsers_to_generate = vec![];
-        let mut option_parsers_to_generate = vec![];
-        for (parser_node_name, typedef) in syntax.typedefs_by_name() {
-            if typedef.is_optional() {
-                let content_name = TypeName::type_spec(typedef.spec());
-                let content_node_name = syntax
-                    .get_node_name(&content_name)
-                    .unwrap_or_else(|| {
-                        panic!(
-                            "While generating an option parser, could not find node name {}",
-                            content_name
-                        )
-                    })
-                    .clone();
-                debug!(target: "generate_spidermonkey", "CPPExporter::new adding optional typedef {:?} => {:?} => {:?}",
-                    parser_node_name,
-                    content_name,
-                    content_node_name);
-                option_parsers_to_generate.push(OptionParserData {
-                    name: parser_node_name.clone(),
-                    elements: content_node_name,
-                });
-            } else if let TypeSpec::Array {
-                ref contents,
-                ref supports_empty,
-            } = *typedef.spec()
-            {
-                let content_name = TypeName::type_(&**contents);
-                let content_node_name = syntax
-                    .get_node_name(&content_name)
-                    .unwrap_or_else(|| {
-                        panic!(
-                            "While generating an array parser, could not find node name {}",
-                            content_name
-                        )
-                    })
-                    .clone();
-                list_parsers_to_generate.push(ListParserData {
-                    name: parser_node_name.clone(),
-                    supports_empty: *supports_empty,
-                    elements: content_node_name,
-                });
-            }
-        }
-        list_parsers_to_generate.sort_by(|a, b| str::cmp(a.name.to_str(), b.name.to_str()));
-        option_parsers_to_generate.sort_by(|a, b| str::cmp(a.name.to_str(), b.name.to_str()));
-
-        // Prepare variant_by_symbol, which will let us lookup the BinVariant name of
-        // a symbol. Since some symbols can appear in several enums (e.g. "+"
-        // is both a unary and a binary operator), we need to collect all the
-        // string enums that contain each symbol and come up with a unique name
-        // (note that there is no guarantee of unicity – if collisions show up,
-        // we may need to tweak the name generation algorithm).
-        let mut enum_by_string: HashMap<String, Vec<NodeName>> = HashMap::new();
-        for (name, enum_) in syntax.string_enums_by_name().iter() {
-            for string in enum_.strings().iter() {
-                let vec = enum_by_string
-                    .entry(string.clone())
-                    .or_insert_with(|| vec![]);
-                vec.push(name.clone());
-            }
-        }
-        let variants_by_symbol = enum_by_string
-            .drain()
-            .map(|(string, names)| {
-                let expanded = format!(
-                    "{names}{symbol}",
-                    names = names
-                        .iter()
-                        .map(NodeName::to_str)
-                        .sorted()
-                        .into_iter()
-                        .format("Or"),
-                    symbol = string.to_cpp_enum_case()
-                );
-                (string, expanded)
-            })
-            .collect();
-
-        CPPExporter {
-            syntax,
-            rules,
-            list_parsers_to_generate,
-            option_parsers_to_generate,
-            variants_by_symbol,
-        }
-    }
-
-    // ----- Generating the header
-
-    /// Get the type representing a success for parsing this node.
-    fn get_type_ok(&self, name: &NodeName, default: &str) -> String {
-        let rules_for_this_interface = self.rules.get(name);
-        // If the override is provided, use it.
-        if let Some(ref type_ok) = rules_for_this_interface.type_ok {
-            return type_ok.to_string();
-        }
-        default.to_string()
-    }
-
-    fn get_method_signature(
-        &self,
-        name: &NodeName,
-        default_type_ok: &str,
-        prefix: &str,
-        args: &str,
-    ) -> String {
-        let type_ok = self.get_type_ok(name, default_type_ok);
-        let kind = name.to_class_cases();
-        format!(
-            "    JS::Result<{type_ok}> parse{prefix}{kind}({args});\n",
-            prefix = prefix,
-            type_ok = type_ok,
-            kind = kind,
-            args = args,
-        )
-    }
-
-    fn get_method_definition_start(
-        &self,
-        name: &NodeName,
-        default_type_ok: &str,
-        prefix: &str,
-        args: &str,
-    ) -> String {
-        let type_ok = self.get_type_ok(name, default_type_ok);
-        let kind = name.to_class_cases();
-        format!("template<typename Tok> JS::Result<{type_ok}>\nBinASTParser<Tok>::parse{prefix}{kind}({args})",
-            prefix = prefix,
-            type_ok = type_ok,
-            kind = kind,
-            args = args,
-        )
-    }
-
-    /// Declaring enums for kinds and fields.
-    fn export_declare_kinds_and_fields_enums(&self, buffer: &mut String) {
-        buffer.push_str(&self.rules.hpp_tokens_header.reindent(""));
-
-        buffer.push_str("\n\n");
-        if self.rules.hpp_tokens_kind_doc.is_some() {
-            buffer.push_str(&self.rules.hpp_tokens_kind_doc.reindent(""));
-        }
-
-        let node_names = self.syntax.node_names().keys().sorted();
-        buffer.push_str(&format!(
-            "\n#define FOR_EACH_BIN_KIND(F) \\\n{nodes}\n",
-            nodes = node_names
-                .map(|name| format!(
-                    "    F({enum_name}, \"{spec_name}\")",
-                    enum_name = name.to_cpp_enum_case(),
-                    spec_name = name
-                ))
-                .format(" \\\n")
-        ));
-        buffer.push_str(
-            "
-enum class BinKind {
-#define EMIT_ENUM(name, _) name,
-    FOR_EACH_BIN_KIND(EMIT_ENUM)
-#undef EMIT_ENUM
-};
-",
-        );
-
-        buffer.push_str(&format!("\n// The number of distinct values of BinKind.\nconst size_t BINKIND_LIMIT = {};\n\n\n", self.syntax.node_names().len()));
-        buffer.push_str("\n\n");
-        if self.rules.hpp_tokens_field_doc.is_some() {
-            buffer.push_str(&self.rules.hpp_tokens_field_doc.reindent(""));
-        }
-
-        let field_names = self.syntax.field_names().keys().sorted();
-        buffer.push_str(&format!(
-            "\n#define FOR_EACH_BIN_FIELD(F) \\\n{nodes}\n",
-            nodes = field_names
-                .map(|name| format!(
-                    "    F({enum_name}, \"{spec_name}\")",
-                    spec_name = name,
-                    enum_name = name.to_cpp_enum_case()
-                ))
-                .format(" \\\n")
-        ));
-        buffer.push_str(
-            "
-enum class BinField {
-#define EMIT_ENUM(name, _) name,
-    FOR_EACH_BIN_FIELD(EMIT_ENUM)
-#undef EMIT_ENUM
-};
-",
-        );
-        buffer.push_str(&format!("\n// The number of distinct values of BinField.\nconst size_t BINFIELD_LIMIT = {};\n\n\n", self.syntax.field_names().len()));
-
-        if self.rules.hpp_tokens_variants_doc.is_some() {
-            buffer.push_str(&self.rules.hpp_tokens_variants_doc.reindent(""));
-        }
-        let enum_variants = self.variants_by_symbol.iter().sorted_by(
-            |&(ref symbol_1, ref name_1), &(ref symbol_2, ref name_2)| {
-                Ord::cmp(name_1, name_2).then_with(|| Ord::cmp(symbol_1, symbol_2))
-            },
-        );
-
-        buffer.push_str(&format!(
-            "\n#define FOR_EACH_BIN_VARIANT(F) \\\n{nodes}\n",
-            nodes = enum_variants
-                .map(|(symbol, name)| format!(
-                    "    F({variant_name}, \"{spec_name}\")",
-                    spec_name = symbol,
-                    variant_name = name
-                ))
-                .format(" \\\n")
-        ));
-
-        buffer.push_str(
-            "
-enum class BinVariant {
-#define EMIT_ENUM(name, _) name,
-    FOR_EACH_BIN_VARIANT(EMIT_ENUM)
-#undef EMIT_ENUM
-};
-",
-        );
-        buffer.push_str(&format!("\n// The number of distinct values of BinVariant.\nconst size_t BINVARIANT_LIMIT = {};\n\n\n",
-            self.variants_by_symbol.len()));
-
-        buffer.push_str(&self.rules.hpp_tokens_footer.reindent(""));
-        buffer.push_str("\n");
-    }
-
-    /// Declare string enums
-    fn export_declare_string_enums_classes(&self, buffer: &mut String) {
-        buffer.push_str("\n\n// ----- Declaring string enums (by lexicographical order)\n");
-        let string_enums_by_name = self
-            .syntax
-            .string_enums_by_name()
-            .iter()
-            .sorted_by(|a, b| str::cmp(a.0.to_str(), b.0.to_str()));
-        for (name, enum_) in string_enums_by_name {
-            let rendered_cases = enum_
-                .strings()
-                .iter()
-                .map(|str| {
-                    format!(
-                        "{case:<20}      /* \"{original}\" */",
-                        case = str.to_cpp_enum_case(),
-                        original = str
-                    )
-                })
-                .format(",\n    ");
-            let rendered = format!(
-                "enum class {name} {{\n    {cases}\n}};\n\n",
-                cases = rendered_cases,
-                name = name.to_class_cases()
-            );
-            buffer.push_str(&rendered);
-        }
-    }
-
-    fn export_declare_sums_of_interface_methods(&self, buffer: &mut String) {
-        let sums_of_interfaces = self
-            .syntax
-            .resolved_sums_of_interfaces_by_name()
-            .iter()
-            .sorted_by(|a, b| a.0.cmp(&b.0))
-            .collect::<Vec<_>>();
-        buffer.push_str("\n\n// ----- Sums of interfaces (by lexicographical order)\n");
-        buffer.push_str("// Implementations are autogenerated\n");
-        buffer.push_str("// `ParseNode*` may never be nullptr\n");
-        for &(ref name, _) in &sums_of_interfaces {
-            let rendered = self.get_method_signature(name, "ParseNode*", "", "");
-            buffer.push_str(&rendered.reindent(""));
-        }
-        for (name, _) in sums_of_interfaces {
-            let rendered = self.get_method_signature(
-                name,
-                "ParseNode*",
-                "Sum",
-                "const size_t start, const BinKind kind, const BinFields& fields",
-            );
-            buffer.push_str(&rendered.reindent(""));
-        }
-    }
-
-    fn export_declare_single_interface_methods(&self, buffer: &mut String) {
-        buffer.push_str("\n\n// ----- Interfaces (by lexicographical order)\n");
-        buffer.push_str("// Implementations are autogenerated\n");
-        buffer.push_str("// `ParseNode*` may never be nullptr\n");
-        let interfaces_by_name = self
-            .syntax
-            .interfaces_by_name()
-            .iter()
-            .sorted_by(|a, b| str::cmp(a.0.to_str(), b.0.to_str()));
-
-        let mut outer_parsers = Vec::with_capacity(interfaces_by_name.len());
-        let mut inner_parsers = Vec::with_capacity(interfaces_by_name.len());
-
-        for (name, _) in interfaces_by_name {
-            let outer = self.get_method_signature(name, "ParseNode*", "", "");
-            let inner = self.get_method_signature(
-                name,
-                "ParseNode*",
-                "Interface",
-                "const size_t start, const BinKind kind, const BinFields& fields",
-            );
-            outer_parsers.push(outer.reindent(""));
-            inner_parsers.push(inner.reindent(""));
-        }
-
-        for parser in outer_parsers.drain(..) {
-            buffer.push_str(&parser);
-            buffer.push_str("\n");
-        }
-
-        for parser in inner_parsers.drain(..) {
-            buffer.push_str(&parser);
-            buffer.push_str("\n");
-        }
-    }
-
-    fn export_declare_string_enums_methods(&self, buffer: &mut String) {
-        buffer.push_str("\n\n// ----- String enums (by lexicographical order)\n");
-        buffer.push_str("// Implementations are autogenerated\n");
-        let string_enums_by_name = self
-            .syntax
-            .string_enums_by_name()
-            .iter()
-            .sorted_by(|a, b| str::cmp(a.0.to_str(), b.0.to_str()));
-        for (kind, _) in string_enums_by_name {
-            let type_ok = format!(
-                "typename BinASTParser<Tok>::{kind}",
-                kind = kind.to_class_cases()
-            );
-            let rendered = self.get_method_signature(kind, &type_ok, "", "");
-            buffer.push_str(&rendered.reindent(""));
-            buffer.push_str("\n");
-        }
-    }
-
-    fn export_declare_list_methods(&self, buffer: &mut String) {
-        buffer.push_str("\n\n// ----- Lists (by lexicographical order)\n");
-        buffer.push_str("// Implementations are autogenerated\n");
-        for parser in &self.list_parsers_to_generate {
-            let rendered = self.get_method_signature(&parser.name, "ParseNode*", "", "");
-            buffer.push_str(&rendered.reindent(""));
-            buffer.push_str("\n");
-        }
-    }
-
-    fn export_declare_option_methods(&self, buffer: &mut String) {
-        buffer.push_str("\n\n// ----- Default values (by lexicographical order)\n");
-        buffer.push_str("// Implementations are autogenerated\n");
-        for parser in &self.option_parsers_to_generate {
-            let rendered = self.get_method_signature(&parser.name, "ParseNode*", "", "");
-            buffer.push_str(&rendered.reindent(""));
-            buffer.push_str("\n");
-        }
-    }
-
-    fn generate_autogenerated_warning(&self) -> String {
-        let warning = format!(
-            "// This file was autogenerated by binjs_generate_spidermonkey,
-// please DO NOT EDIT BY HAND.
-"
-        );
-        warning
-    }
-
-    /// Generate C++ headers for SpiderMonkey
-    fn to_spidermonkey_token_hpp(&self) -> String {
-        let mut buffer = String::new();
-
-        buffer.push_str(&self.generate_autogenerated_warning());
-
-        self.export_declare_kinds_and_fields_enums(&mut buffer);
-
-        buffer.push_str("\n");
-        buffer
-    }
-    fn to_spidermonkey_class_hpp(&self) -> String {
-        let mut buffer = String::new();
-
-        buffer.push_str(&self.generate_autogenerated_warning());
-
-        buffer.push_str(&self.rules.hpp_class_header.reindent(""));
-        buffer.push_str("\n");
-
-        self.export_declare_string_enums_classes(&mut buffer);
-        self.export_declare_sums_of_interface_methods(&mut buffer);
-        self.export_declare_single_interface_methods(&mut buffer);
-        self.export_declare_string_enums_methods(&mut buffer);
-        self.export_declare_list_methods(&mut buffer);
-        self.export_declare_option_methods(&mut buffer);
-
-        buffer.push_str("\n");
-        buffer
-    }
-}
-
-impl CPPExporter {
-    /// Generate implementation of a single typesum.
-    fn generate_implement_sum(
-        &self,
-        buffer: &mut String,
-        name: &NodeName,
-        nodes: &HashSet<NodeName>,
-    ) {
-        // Generate comments (FIXME: We should use the actual webidl, not the resolved sum)
-        let nodes = nodes.iter().sorted().collect::<Vec<_>>();
-        let kind = name.to_class_cases();
-        let rendered_bnf = format!(
-            "/*\n{name} ::= {nodes}\n*/",
-            nodes = nodes.iter().format("\n    "),
-            name = name.to_str()
-        );
-
-        // Generate outer method
-        buffer.push_str(&format!(
-            "{bnf}
-{first_line}
-{{
-    BinKind kind;
-    BinFields fields(cx_);
-    AutoTaggedTuple guard(*tokenizer_);
-    const auto start = tokenizer_->offset();
-
-    MOZ_TRY(tokenizer_->enterTaggedTuple(kind, fields, guard));
-
-    BINJS_MOZ_TRY_DECL(result, parseSum{kind}(start, kind, fields));
-
-    MOZ_TRY(guard.done());
-    return result;
-}}\n",
-            bnf = rendered_bnf,
-            kind = kind,
-            first_line = self.get_method_definition_start(name, "ParseNode*", "", "")
-        ));
-
-        // Generate inner method
-        let mut buffer_cases = String::new();
-        for node in nodes {
-            buffer_cases.push_str(&format!(
-                "
-      case BinKind::{variant_name}:
-        MOZ_TRY_VAR(result, parseInterface{class_name}(start, kind, fields));
-        break;",
-                class_name = node.to_class_cases(),
-                variant_name = node.to_cpp_enum_case()
-            ));
-        }
-        buffer.push_str(&format!(
-            "\n{first_line}
-{{
-    {type_ok} result;
-    switch(kind) {{{cases}
-      default:
-        return raiseInvalidKind(\"{kind}\", kind);
-    }}
-    return result;
-}}
-
-",
-            kind = kind,
-            cases = buffer_cases,
-            first_line = self.get_method_definition_start(
-                name,
-                "ParseNode*",
-                "Sum",
-                "const size_t start, const BinKind kind, const BinFields& fields"
-            ),
-            type_ok = self.get_type_ok(name, "ParseNode*")
-        ));
-    }
-
-    /// Generate the implementation of a single list parser
-    fn generate_implement_list(&self, buffer: &mut String, parser: &ListParserData) {
-        let rules_for_this_list = self.rules.get(&parser.name);
-
-        // Warn if some rules are unused.
-        for &(condition, name) in &[
-            (rules_for_this_list.build_result.is_some(), "build:"),
-            (rules_for_this_list.type_ok.is_some(), "type-ok:"),
-            (rules_for_this_list.by_field.len() > 0, "fields:"),
-        ] {
-            if condition {
-                warn!(
-                    "In {}, rule `{}` was specified but is ignored.",
-                    parser.name, name
-                );
-            }
-        }
-
-        let kind = parser.name.to_class_cases();
-        let first_line = self.get_method_definition_start(&parser.name, "ParseNode*", "", "");
-
-        let init = match rules_for_this_list.init {
-            Some(str) => str.reindent("    "),
-            None => {
-                // We cannot generate the method if we don't know how to initialize the list.
-                let rendered = format!(
-                    "
-{first_line}
-{{
-    return raiseError(\"FIXME: Not implemented yet ({kind})\");
-}}\n",
-                    first_line = first_line,
-                    kind = kind,
-                );
-                buffer.push_str(&rendered);
-                return;
-            }
-        };
-        let append = match rules_for_this_list.append {
-            Some(str) => format!("{}", str.reindent("        ")),
-            None => "        result->appendWithoutOrderAssumption(item);".to_string(),
-        };
-
-        let rendered = format!(
-            "\n{first_line}
-{{
-    uint32_t length;
-    AutoList guard(*tokenizer_);
-
-    const auto start = tokenizer_->offset();
-    MOZ_TRY(tokenizer_->enterList(length, guard));{empty_check}
-{init}
-
-    for (uint32_t i = 0; i < length; ++i) {{
-        BINJS_MOZ_TRY_DECL(item, parse{inner}());
-{append}
-    }}
-
-    MOZ_TRY(guard.done());
-    return result;
-}}\n",
-            first_line = first_line,
-            empty_check = if parser.supports_empty {
-                "".to_string()
-            } else {
-                format!(
-                    "\n    if (length == 0)\n         return raiseEmpty(\"{kind}\");\n",
-                    kind = kind
-                )
-            },
-            inner = parser.elements.to_class_cases(),
-            init = init,
-            append = append
-        );
-        buffer.push_str(&rendered);
-    }
-
-    fn generate_implement_option(&self, buffer: &mut String, parser: &OptionParserData) {
-        debug!(target: "generate_spidermonkey", "Implementing optional value {} backed by {}",
-            parser.name.to_str(), parser.elements.to_str());
-
-        let rules_for_this_node = self.rules.get(&parser.name);
-
-        // Warn if some rules are unused.
-        for &(condition, name) in &[
-            (rules_for_this_node.build_result.is_some(), "build:"),
-            (rules_for_this_node.append.is_some(), "append:"),
-            (rules_for_this_node.by_field.len() > 0, "fields:"),
-        ] {
-            if condition {
-                warn!(
-                    "In {}, rule `{}` was specified but is ignored.",
-                    parser.name, name
-                );
-            }
-        }
-
-        let type_ok = self.get_type_ok(&parser.name, "ParseNode*");
-        let default_value = if type_ok == "Ok" { "Ok()" } else { "nullptr" }.to_string();
-
-        // At this stage, thanks to deanonymization, `contents`
-        // is something like `OptionalFooBar`.
-        let named_implementation = if let Some(NamedType::Typedef(ref typedef)) =
-            self.syntax.get_type_by_name(&parser.name)
-        {
-            assert!(typedef.is_optional());
-            if let TypeSpec::NamedType(ref named) = *typedef.spec() {
-                self.syntax.get_type_by_name(named).unwrap_or_else(|| {
-                    panic!(
-                        "Internal error: Could not find type {}, which should have been generated.",
-                        named.to_str()
-                    )
-                })
-            } else {
-                panic!(
-                    "Internal error: In {}, type {:?} should have been a named type",
-                    parser.name.to_str(),
-                    typedef
-                );
-            }
-        } else {
-            panic!(
-                "Internal error: In {}, there should be a type with that name",
-                parser.name.to_str()
-            );
-        };
-        match named_implementation {
-            NamedType::Interface(_) => {
-                buffer.push_str(&format!(
-                    "{first_line}
-{{
-    BinKind kind;
-    BinFields fields(cx_);
-    AutoTaggedTuple guard(*tokenizer_);
-
-    MOZ_TRY(tokenizer_->enterTaggedTuple(kind, fields, guard));
-    {type_ok} result;
-    if (kind == BinKind::{null}) {{
-        result = {default_value};
-    }} else {{
-        const auto start = tokenizer_->offset();
-        MOZ_TRY_VAR(result, parseInterface{contents}(start, kind, fields));
-    }}
-    MOZ_TRY(guard.done());
-
-    return result;
-}}
-
-",
-                    first_line =
-                        self.get_method_definition_start(&parser.name, "ParseNode*", "", ""),
-                    null = self.syntax.get_null_name().to_cpp_enum_case(),
-                    contents = parser.elements.to_class_cases(),
-                    type_ok = type_ok,
-                    default_value = default_value,
-                ));
-            }
-            NamedType::Typedef(ref type_) => match type_.spec() {
-                &TypeSpec::TypeSum(_) => {
-                    buffer.push_str(&format!(
-                        "{first_line}
-{{
-    BinKind kind;
-    BinFields fields(cx_);
-    AutoTaggedTuple guard(*tokenizer_);
-
-    MOZ_TRY(tokenizer_->enterTaggedTuple(kind, fields, guard));
-    {type_ok} result;
-    if (kind == BinKind::{null}) {{
-        result = {default_value};
-    }} else {{
-        const auto start = tokenizer_->offset();
-        MOZ_TRY_VAR(result, parseSum{contents}(start, kind, fields));
-    }}
-    MOZ_TRY(guard.done());
-
-    return result;
-}}
-
-",
-                        first_line =
-                            self.get_method_definition_start(&parser.name, "ParseNode*", "", ""),
-                        contents = parser.elements.to_class_cases(),
-                        type_ok = type_ok,
-                        default_value = default_value,
-                        null = self.syntax.get_null_name().to_cpp_enum_case(),
-                    ));
-                }
-                &TypeSpec::String => {
-                    let build_result = rules_for_this_node.init.reindent("    ");
-                    let first_line =
-                        self.get_method_definition_start(&parser.name, "ParseNode*", "", "");
-                    if build_result.len() == 0 {
-                        buffer.push_str(&format!(
-                            "{first_line}
-{{
-    return raiseError(\"FIXME: Not implemented yet ({kind})\");
-}}
-
-",
-                            first_line = first_line,
-                            kind = parser.name.to_str()
-                        ));
-                    } else {
-                        buffer.push_str(&format!(
-                            "{first_line}
-{{
-    BINJS_MOZ_TRY_DECL(result, tokenizer_->readMaybeAtom());
-
-{build}
-
-    return result;
-}}
-
-",
-                            first_line = first_line,
-                            build = build_result,
-                        ));
-                    }
-                }
-                _else => unimplemented!("{:?}", _else),
-            },
-            NamedType::StringEnum(_) => unimplemented!(),
-        }
-    }
-
-    fn generate_implement_interface(
-        &self,
-        buffer: &mut String,
-        name: &NodeName,
-        interface: &Interface,
-    ) {
-        let rules_for_this_interface = self.rules.get(name);
-
-        for &(condition, rule_name) in &[(rules_for_this_interface.append.is_some(), "build:")] {
-            if condition {
-                warn!(
-                    "In {}, rule `{}` was specified but is ignored.",
-                    name, rule_name
-                );
-            }
-        }
-
-        // Generate comments
-        let comment = format!("\n/*\n{}*/\n", ToWebidl::interface(interface, "", "    "));
-        buffer.push_str(&comment);
-
-        // Generate public method
-        let kind = name.to_class_cases();
-        buffer.push_str(&format!(
-            "{first_line}
-{{
-    BinKind kind;
-    BinFields fields(cx_);
-    AutoTaggedTuple guard(*tokenizer_);
-
-    MOZ_TRY(tokenizer_->enterTaggedTuple(kind, fields, guard));
-    const auto start = tokenizer_->offset();
-
-    BINJS_MOZ_TRY_DECL(result, parseInterface{kind}(start, kind, fields));
-    MOZ_TRY(guard.done());
-
-    return result;
-}}
-
-",
-            first_line = self.get_method_definition_start(name, "ParseNode*", "", ""),
-            kind = kind
-        ));
-
-        // Generate aux method
-        let number_of_fields = interface.contents().fields().len();
-        let first_line = self.get_method_definition_start(
-            name,
-            "ParseNode*",
-            "Interface",
-            "const size_t start, const BinKind kind, const BinFields& fields",
-        );
-
-        let fields_type_list = format!(
-            "{{ {} }}",
-            interface
-                .contents()
-                .fields()
-                .iter()
-                .map(|field| format!("BinField::{}", field.name().to_cpp_enum_case()))
-                .format(", ")
-        );
-
-        let mut fields_implem = String::new();
-        for field in interface.contents().fields() {
-            let rules_for_this_field = rules_for_this_interface
-                .by_field
-                .get(field.name())
-                .cloned()
-                .unwrap_or_default();
-            let needs_block = rules_for_this_field.block_before_field.is_some()
-                || rules_for_this_field.block_after_field.is_some();
-
-            let var_name = field.name().to_cpp_field_case();
-            let (decl_var, parse_var) = match field.type_().get_primitive(&self.syntax) {
-                Some(IsNullable {
-                    is_nullable: false,
-                    content: Primitive::Number,
-                }) => {
-                    if needs_block {
-                        (
-                            Some(format!("double {var_name};", var_name = var_name)),
-                            Some(format!(
-                                "MOZ_TRY_VAR({var_name}, tokenizer_->readDouble());",
-                                var_name = var_name
-                            )),
-                        )
-                    } else {
-                        (
-                            None,
-                            Some(format!(
-                                "BINJS_MOZ_TRY_DECL({var_name}, tokenizer_->readDouble());",
-                                var_name = var_name
-                            )),
-                        )
-                    }
-                }
-                Some(IsNullable {
-                    is_nullable: false,
-                    content: Primitive::Boolean,
-                }) => {
-                    if needs_block {
-                        (
-                            Some(format!("bool {var_name};", var_name = var_name)),
-                            Some(format!(
-                                "MOZ_TRY_VAR({var_name}, tokenizer_->readBool());",
-                                var_name = var_name
-                            )),
-                        )
-                    } else {
-                        (
-                            None,
-                            Some(format!(
-                                "BINJS_MOZ_TRY_DECL({var_name}, tokenizer_->readBool());",
-                                var_name = var_name
-                            )),
-                        )
-                    }
-                }
-                Some(IsNullable {
-                    is_nullable: false,
-                    content: Primitive::Offset,
-                }) => {
-                    if needs_block {
-                        (
-                            Some(format!("uint32_t {var_name};", var_name = var_name)),
-                            Some(format!(
-                                "MOZ_TRY_VAR({var_name}, tokenizer_->readOffset());",
-                                var_name = var_name
-                            )),
-                        )
-                    } else {
-                        (
-                            None,
-                            Some(format!(
-                                "BINJS_MOZ_TRY_DECL({var_name}, tokenizer_->readOffset());",
-                                var_name = var_name
-                            )),
-                        )
-                    }
-                }
-                Some(IsNullable {
-                    content: Primitive::Void,
-                    ..
-                }) => {
-                    warn!("Internal error: We shouldn't have any `void` types at this stage.");
-                    (
-                        Some(format!("// Skipping void field {}", field.name().to_str())),
-                        None,
-                    )
-                }
-                Some(IsNullable {
-                    is_nullable: false,
-                    content: Primitive::String,
-                }) => (
-                    Some(format!("RootedAtom {var_name}(cx_);", var_name = var_name)),
-                    Some(format!(
-                        "MOZ_TRY_VAR({var_name}, tokenizer_->readAtom());",
-                        var_name = var_name
-                    )),
-                ),
-                Some(IsNullable {
-                    content: Primitive::Interface(ref interface),
-                    ..
-                }) if &self.get_type_ok(interface.name(), "?") == "Ok" => {
-                    // Special case: `Ok` means that we shouldn't bind the return value.
-                    let typename = TypeName::type_(field.type_());
-                    (
-                        None,
-                        Some(format!("MOZ_TRY(parse{typename}());", typename = typename)),
-                    )
-                }
-                _else => {
-                    let typename = TypeName::type_(field.type_());
-                    if needs_block {
-                        (
-                            Some(format!(
-                                "{typename} {var_name};",
-                                var_name = var_name,
-                                typename = typename
-                            )),
-                            Some(format!(
-                                "MOZ_TRY_VAR({var_name}, parse{typename}());",
-                                var_name = var_name,
-                                typename = typename
-                            )),
-                        )
-                    } else {
-                        (
-                            None,
-                            Some(format!(
-                                "BINJS_MOZ_TRY_DECL({var_name}, parse{typename}());",
-                                var_name = var_name,
-                                typename = typename
-                            )),
-                        )
-                    }
-                }
-            };
-
-            let rendered = {
-                if rules_for_this_field.replace.is_some() {
-                    for &(condition, rule_name) in &[
-                        (rules_for_this_field.before_field.is_some(), "before:"),
-                        (rules_for_this_field.after_field.is_some(), "after:"),
-                        (rules_for_this_field.declare.is_some(), "declare:"),
-                    ] {
-                        if condition {
-                            warn!("In {}, rule `{}` was specified but is ignored because `replace:` is also specified.", name, rule_name);
-                        }
-                    }
-                    rules_for_this_field.replace.reindent("    ").newline()
-                } else {
-                    let before_field = rules_for_this_field.before_field.reindent("    ");
-                    let after_field = rules_for_this_field.after_field.reindent("    ");
-                    let decl_var = if rules_for_this_field.declare.is_some() {
-                        rules_for_this_field.declare.reindent("    ")
-                    } else {
-                        decl_var.reindent("    ")
-                    };
-                    if needs_block {
-                        let parse_var = parse_var.reindent("        ");
-                        format!(
-                            "{before_field}
-{decl_var}
-    {{
-{block_before_field}
-{parse_var}
-{block_after_field}
-    }}
-{after_field}",
-                            before_field = before_field.reindent("    "),
-                            decl_var = decl_var.reindent("    "),
-                            parse_var = parse_var.reindent("        "),
-                            after_field = after_field.reindent("    "),
-                            block_before_field =
-                                rules_for_this_field.block_before_field.reindent("        "),
-                            block_after_field =
-                                rules_for_this_field.block_after_field.reindent("        ")
-                        )
-                    } else {
-                        // We have a before_field and an after_field. This will create newlines
-                        // for them.
-                        format!(
-                            "
-{before_field}
-{decl_var}
-{parse_var}
-{after_field}
-",
-                            before_field = before_field.reindent("    "),
-                            decl_var = decl_var.reindent("    "),
-                            parse_var = parse_var.reindent("    "),
-                            after_field = after_field.reindent("    ")
-                        )
-                    }
-                }
-            };
-            fields_implem.push_str(&rendered);
-        }
-
-        let init = rules_for_this_interface.init.reindent("    ");
-        let build_result = rules_for_this_interface.build_result.reindent("    ");
-
-        if build_result == "" {
-            buffer.push_str(&format!(
-                "{first_line}
-{{
-    return raiseError(\"FIXME: Not implemented yet ({})\");
-}}
-
-",
-                kind = kind.to_str(),
-                first_line = first_line,
-            ));
-        } else {
-            let check_fields = if number_of_fields == 0 {
-                format!("MOZ_TRY(tokenizer_->checkFields0(kind, fields));")
-            } else {
-                format!(
-                    "MOZ_TRY(tokenizer_->checkFields(kind, fields, {fields_type_list}));",
-                    fields_type_list = fields_type_list
-                )
-            };
-            buffer.push_str(&format!(
-                "{first_line}
-{{
-    MOZ_ASSERT(kind == BinKind::{kind});
-    CheckRecursionLimit(cx_);
-
-    {check_fields}
-{pre}{fields_implem}
-{post}
-    return result;
-}}
-
-",
-                check_fields = check_fields,
-                fields_implem = fields_implem,
-                pre = init,
-                post = build_result,
-                kind = name.to_cpp_enum_case(),
-                first_line = first_line,
-            ));
-        }
-    }
-
-    /// Generate C++ code for SpiderMonkey
-    fn to_spidermonkey_cpp(&self) -> String {
-        let mut buffer = String::new();
-
-        buffer.push_str(&self.generate_autogenerated_warning());
-
-        // 0. Header
-        buffer.push_str(&self.rules.cpp_header.reindent(""));
-        buffer.push_str("\n");
-
-        // 1. Typesums
-        buffer.push_str(
-            "\n\n// ----- Sums of interfaces (autogenerated, by lexicographical order)\n",
-        );
-        buffer.push_str("// Sums of sums are flattened.\n");
-
-        let sums_of_interfaces = self
-            .syntax
-            .resolved_sums_of_interfaces_by_name()
-            .iter()
-            .sorted_by(|a, b| a.0.cmp(&b.0));
-
-        for (name, nodes) in sums_of_interfaces {
-            self.generate_implement_sum(&mut buffer, name, nodes);
-        }
-
-        // 2. Single interfaces
-        buffer.push_str("\n\n// ----- Interfaces (autogenerated, by lexicographical order)\n");
-        buffer.push_str("// When fields have a non-trivial type, implementation is deanonymized and delegated to another parser.\n");
-        let interfaces_by_name = self
-            .syntax
-            .interfaces_by_name()
-            .iter()
-            .sorted_by(|a, b| str::cmp(a.0.to_str(), b.0.to_str()));
-
-        for (name, interface) in interfaces_by_name {
-            self.generate_implement_interface(&mut buffer, name, interface);
-        }
-
-        // 3. String Enums
-        buffer.push_str("\n\n// ----- String enums (autogenerated, by lexicographical order)\n");
-        {
-            let string_enums_by_name = self
-                .syntax
-                .string_enums_by_name()
-                .iter()
-                .sorted_by(|a, b| str::cmp(a.0.to_str(), b.0.to_str()));
-            for (kind, enum_) in string_enums_by_name {
-                let convert = format!(
-                    "    switch (variant) {{
-{cases}
-      default:
-        return raiseInvalidVariant(\"{kind}\", variant);
-    }}",
-                    kind = kind,
-                    cases = enum_
-                        .strings()
-                        .iter()
-                        .map(|symbol| format!(
-                            "    case BinVariant::{binvariant_variant}:
-        return {kind}::{specialized_variant};",
-                            kind = kind,
-                            specialized_variant = symbol.to_cpp_enum_case(),
-                            binvariant_variant = self.variants_by_symbol.get(symbol).unwrap()
-                        ))
-                        .format("\n")
-                );
-
-                let rendered_doc = format!(
-                    "/*\nenum {kind} {{\n{cases}\n}};\n*/\n",
-                    kind = kind,
-                    cases = enum_
-                        .strings()
-                        .iter()
-                        .map(|s| format!("    \"{}\"", s))
-                        .format(",\n")
-                );
-                buffer.push_str(&format!(
-                    "{rendered_doc}{first_line}
-{{
-    BINJS_MOZ_TRY_DECL(variant, tokenizer_->readVariant());
-
-{convert}
-}}
-
-",
-                    rendered_doc = rendered_doc,
-                    convert = convert,
-                    first_line = self.get_method_definition_start(
-                        kind,
-                        &format!("typename BinASTParser<Tok>::{kind}", kind = kind),
-                        "",
-                        ""
-                    )
-                ));
-            }
-        }
-
-        // 4. Lists
-        buffer.push_str("\n\n// ----- Lists (autogenerated, by lexicographical order)\n");
-        for parser in &self.list_parsers_to_generate {
-            self.generate_implement_list(&mut buffer, parser);
-        }
-
-        // 5. Optional values
-        buffer.push_str("\n\n    // ----- Default values (by lexicographical order)\n");
-        for parser in &self.option_parsers_to_generate {
-            self.generate_implement_option(&mut buffer, parser);
-        }
-
-        buffer.push_str("\n");
-        buffer.push_str(&self.rules.cpp_footer.reindent(""));
-        buffer.push_str("\n");
-
-        buffer
-    }
-}
-
-fn update_rule(rule: &mut Option<String>, entry: &yaml_rust::Yaml) -> Result<Option<()>, ()> {
-    if entry.is_badvalue() {
-        return Ok(None);
-    } else if let Some(as_str) = entry.as_str() {
-        *rule = Some(as_str.to_string());
-        Ok(Some(()))
-    } else {
-        Err(())
-    }
-}
-
-fn main() {
-    env_logger::init();
-
-    let matches = App::new("BinAST C++ parser generator")
-        .author("David Teller, <dteller@mozilla.com>")
-        .about("Converts an webidl syntax definition and a yaml set of rules into the C++ source code of a parser.")
-        .args(&[
-            Arg::with_name("INPUT.webidl")
-                .required(true)
-                .help("Input webidl file to use. Must be a webidl source file."),
-            Arg::with_name("INPUT.yaml")
-                .required(true)
-                .help("Input rules file to use. Must be a yaml source file."),
-            Arg::with_name("OUT_HEADER_CLASS_FILE")
-                .long("out-class")
-                .required(true)
-                .takes_value(true)
-                .help("Output header file (.h, designed to be included from within the class file)"),
-            Arg::with_name("OUT_TOKEN_FILE")
-                .long("out-token")
-                .required(true)
-                .takes_value(true)
-                .help("Output token file (.h)"),
-            Arg::with_name("OUT_IMPL_FILE")
-                .long("out-impl")
-                .required(true)
-                .takes_value(true)
-                .help("Output implementation file (.cpp)"),
-        ])
-    .get_matches();
-
-    let source_path = matches
-        .value_of("INPUT.webidl")
-        .expect("Expected INPUT.webidl");
-
-    let source = fs::read_to_string(source_path).expect("Could not read source");
-
-    println!("...importing webidl");
-    let mut builder =
-        Importer::import(vec![source.as_str()].into_iter()).expect("Could not parse source");
-    let fake_root = builder.node_name("@@ROOT@@"); // Unused
-    let null = builder.node_name(""); // Used
-    builder.add_interface(&null).unwrap();
-    let syntax = builder.into_spec(SpecOptions {
-        root: &fake_root,
-        null: &null,
-    });
-
-    let deanonymizer = TypeDeanonymizer::new(&syntax);
-    let syntax_options = SpecOptions {
-        root: &fake_root,
-        null: &null,
-    };
-    let new_syntax = deanonymizer.into_spec(syntax_options);
-
-    let rules_source_path = matches.value_of("INPUT.yaml").unwrap();
-    println!("...generating rules");
-    let data = fs::read_to_string(rules_source_path).expect("Could not read rules");
-
-    let yaml = yaml_rust::YamlLoader::load_from_str(&data).expect("Could not parse rules");
-    assert_eq!(yaml.len(), 1);
-
-    let global_rules = GlobalRules::new(&new_syntax, &yaml[0]);
-    let exporter = CPPExporter::new(new_syntax, global_rules);
-
-    let write_to = |description, arg, data: &str| {
-        let dest_path = matches.value_of(arg).unwrap();
-        println!(
-            "...exporting {description}: {path}",
-            description = description,
-            path = dest_path
-        );
-        fs::write(&dest_path, data).unwrap_or_else(|e| {
-            panic!(
-                "Could not write {description} at {path}: {error}",
-                description = description,
-                path = dest_path,
-                error = e
-            )
-        });
-    };
-
-    write_to(
-        "C++ class header code",
-        "OUT_HEADER_CLASS_FILE",
-        &exporter.to_spidermonkey_class_hpp(),
-    );
-    write_to(
-        "C++ token header code",
-        "OUT_TOKEN_FILE",
-        &exporter.to_spidermonkey_token_hpp(),
-    );
-    write_to(
-        "C++ token implementation code",
-        "OUT_IMPL_FILE",
-        &exporter.to_spidermonkey_cpp(),
-    );
-
-    println!("...done");
-}
diff --git a/third_party/rust/binjs_meta/src/export.rs b/third_party/rust/binjs_meta/src/export.rs
deleted file mode 100644
index b5fdfa79bc..0000000000
--- a/third_party/rust/binjs_meta/src/export.rs
+++ /dev/null
@@ -1,531 +0,0 @@
-use spec::*;
-use util::*;
-
-use std::collections::{HashMap, HashSet};
-
-use itertools::Itertools;
-
-/// A tool designed to replace all anonymous types in a specification
-/// of the language by explicitly named types.
-///
-/// Consider the following mini-specifications for JSON:
-///
-/// ```idl
-/// interface Value {
-///     attribute (Object or String or Number or Array or Boolean)? value;
-/// }
-/// interface Object {
-///     attribute FrozenArray<Property> properties;
-/// }
-/// interface Property {
-///     attribute DOMString name;
-///     attribute Value value;
-/// }
-/// interface Array {
-///     attribute FrozenArray<Value?> items;
-/// }
-/// // ... Skipping definitions of String, Number, Boolean
-/// ```
-///
-/// The deanonymizer will rewrite them as follows:
-///
-/// ```idl
-/// interface Value { // Deanonymized optional sum
-///     attribute OptionalObjectOrStringOrNumberOrArrayOrBoolean value;
-/// }
-/// interface Object { // Deanonymized list
-///     attribute ListOfProperty properties;
-/// }
-/// interface Property { // No change
-///     attribute DOMString name;
-///     attribute Value value;
-/// }
-/// interface Array { // Deanonymized list of options
-///     attribute ListOfOptionalValue items;
-/// }
-/// // ... Skipping definitions of String, Number, Boolean
-///
-/// typedef ObjectOrStringOrNumberOrArrayOrBoolean? OptionalObjectOrStringOrNumberOrArrayOrBoolean;
-/// typedef (Object
-///          or String
-///          or Number
-///          or Array
-///          or Boolean)
-///          ObjectOrStringOrNumberOrArrayOrBoolean;
-/// typedef FrozenArray<Property> ListOfProperty;
-/// typedef FrozenArray<OptionalValue> ListOfOptionalValue;
-/// typedef Value? Optionalvalue;
-/// ```
-///
-/// This deanonymization lets us cleanly define intermediate data structures and/or parsers
-/// implementing the webidl specification.
-pub struct TypeDeanonymizer {
-    builder: SpecBuilder,
-
-    /// When we encounter `typedef (A or B) C`
-    /// and `typedef (C or D) E`, we deanonymize into
-    /// `typedef (A or B or D) E`.
-    ///
-    /// This maintains the relationship that `E` (value)
-    /// contains `C` (key).
-    supersums_of: HashMap<NodeName, HashSet<NodeName>>,
-}
-impl TypeDeanonymizer {
-    /// Create an empty TypeDeanonymizer.
-    pub fn new(spec: &Spec) -> Self {
-        let mut result = TypeDeanonymizer {
-            builder: SpecBuilder::new(),
-            supersums_of: HashMap::new(),
-        };
-        let mut skip_name_map: HashMap<&FieldName, FieldName> = HashMap::new();
-
-        // Copy field names
-        for (_, name) in spec.field_names() {
-            result.builder.import_field_name(name)
-        }
-
-        for (_, interface) in spec.interfaces_by_name() {
-            for field in interface.contents().fields() {
-                if field.is_lazy() {
-                    let skip_name = result
-                        .builder
-                        .field_name(format!("{}_skip", field.name().to_str()).to_str());
-                    skip_name_map.insert(field.name(), skip_name);
-                }
-            }
-        }
-
-        // Copy and deanonymize interfaces.
-        for (name, interface) in spec.interfaces_by_name() {
-            result.builder.import_node_name(name);
-            // Collect interfaces to copy them into the `builder`
-            // and walk through their fields to deanonymize types.
-
-            let mut fields = vec![];
-
-            // Copy other fields.
-            for field in interface.contents().fields() {
-                result.import_type(spec, field.type_(), None);
-                fields.push(field.clone());
-            }
-
-            // Copy the declaration.
-            let mut declaration = result.builder.add_interface(name).unwrap();
-            for field in fields.drain(..) {
-                // Create *_skip field just before the lazy field.
-                // See also tagged_tuple in write.rs.
-                if field.is_lazy() {
-                    declaration.with_field(
-                        skip_name_map.get(field.name()).unwrap(),
-                        Type::offset().required(),
-                    );
-                }
-                declaration.with_field_laziness(
-                    field.name(),
-                    field.type_().clone(),
-                    field.laziness(),
-                );
-            }
-
-            if let Some(ref field_name) = interface.scoped_dictionary() {
-                declaration.with_scoped_dictionary(field_name);
-            }
-        }
-        // Copy and deanonymize typedefs
-        for (name, definition) in spec.typedefs_by_name() {
-            result.builder.import_node_name(name);
-            if result.builder.get_typedef(name).is_some() {
-                // Already imported by following links.
-                continue;
-            }
-            result.import_type(spec, &definition, Some(name.clone()));
-        }
-        // Copy and deanonymize string enums
-        for (name, definition) in spec.string_enums_by_name() {
-            result.builder.import_node_name(name);
-            let mut strings: Vec<_> = definition.strings().iter().collect();
-            let mut declaration = result.builder.add_string_enum(name).unwrap();
-            for string in strings.drain(..) {
-                declaration.with_string(&string);
-            }
-        }
-        debug!(target: "export_utils", "Names: {:?}", result.builder.names().keys().format(", "));
-
-        result
-    }
-
-    pub fn supersums(&self) -> &HashMap<NodeName, HashSet<NodeName>> {
-        &self.supersums_of
-    }
-
-    /// Convert into a new specification.
-    pub fn into_spec(self, options: SpecOptions) -> Spec {
-        self.builder.into_spec(options)
-    }
-
-    /// If `name` is the name of a (deanonymized) type, return the corresponding type.
-    pub fn get_node_name(&self, name: &str) -> Option<NodeName> {
-        self.builder.get_node_name(name)
-    }
-
-    /// Returns `(sum, name)` where `sum` is `Some(names)` iff this type can be resolved to a sum of interfaces.
-    fn import_type(
-        &mut self,
-        spec: &Spec,
-        type_: &Type,
-        public_name: Option<NodeName>,
-    ) -> (Option<HashSet<NodeName>>, NodeName) {
-        debug!(target: "export_utils", "import_type {:?} => {:?}", public_name, type_);
-        if type_.is_optional() {
-            let (_, spec_name) = self.import_typespec(spec, &type_.spec, None);
-            let my_name = match public_name {
-                None => self.builder.node_name(&format!("Optional{}", spec_name)),
-                Some(ref name) => name.clone(),
-            };
-            let deanonymized = Type::named(&spec_name).optional().unwrap(); // Named types can always be made optional.
-            if let Some(ref mut typedef) = self.builder.add_typedef(&my_name) {
-                debug!(target: "export_utils", "import_type introduced {:?}", my_name);
-                typedef.with_type(deanonymized.clone());
-            } else {
-                debug!(target: "export_utils", "import_type: Attempting to redefine typedef {name}", name = my_name.to_str());
-            }
-            (None, my_name)
-        } else {
-            self.import_typespec(spec, &type_.spec, public_name)
-        }
-    }
-    fn import_typespec(
-        &mut self,
-        spec: &Spec,
-        type_spec: &TypeSpec,
-        public_name: Option<NodeName>,
-    ) -> (Option<HashSet<NodeName>>, NodeName) {
-        debug!(target: "export_utils", "import_typespec {:?} => {:?}", public_name, type_spec);
-        match *type_spec {
-            TypeSpec::Boolean
-            | TypeSpec::Number
-            | TypeSpec::UnsignedLong
-            | TypeSpec::PropertyKey
-            | TypeSpec::IdentifierName
-            | TypeSpec::String
-            | TypeSpec::Offset
-            | TypeSpec::Void => {
-                if let Some(ref my_name) = public_name {
-                    if let Some(ref mut typedef) = self.builder.add_typedef(&my_name) {
-                        debug!(target: "export_utils", "import_typespec: Defining {name} (primitive)", name = my_name.to_str());
-                        typedef.with_type(type_spec.clone().required());
-                    } else {
-                        debug!(target: "export_utils", "import_typespec: Attempting to redefine typedef {name}", name = my_name.to_str());
-                    }
-                }
-                // This is a workaround for typedefs in the webidl that are not truly typedefs.
-                // See https://github.com/Yoric/ecmascript-binary-ast/pull/1
-                let name = match *type_spec {
-                    TypeSpec::PropertyKey => self.builder.node_name("PropertyKey"),
-                    TypeSpec::IdentifierName => self.builder.node_name("IdentifierName"),
-                    _ => self.builder.node_name(&format!("@@{:?}", type_spec)),
-                };
-                (None, name)
-            }
-            TypeSpec::NamedType(ref link) => {
-                let resolved = spec.get_type_by_name(link)
-                    .unwrap_or_else(|| panic!("While deanonymizing, could not find the definition of {} in the original spec.", link.to_str()));
-                let (sum, rewrite, primitive) = match resolved {
-                    NamedType::StringEnum(_) => {
-                        // - Can't use in a sum
-                        // - No rewriting happened.
-                        (None, None, None)
-                    }
-                    NamedType::Typedef(ref type_) => {
-                        // - Might use in a sum.
-                        // - Might be rewritten.
-                        let (sum, name) = self.import_type(spec, type_, Some(link.clone()));
-                        (sum, Some(name), type_.get_primitive(spec))
-                    }
-                    NamedType::Interface(_) => {
-                        // - May use in a sum.
-                        // - If a rewriting takes place, it didn't change the names.
-                        let sum = [link.clone()].iter().cloned().collect();
-                        (Some(sum), None, None)
-                    }
-                };
-                debug!(target: "export_utils", "import_typespec dealing with named type {}, public name {:?} => {:?}",
-                    link, public_name, rewrite);
-                if let Some(ref my_name) = public_name {
-                    // If we have a public name, alias it to `content`
-                    if let Some(content) = rewrite {
-                        let deanonymized = match primitive {
-                            None
-                            | Some(IsNullable {
-                                is_nullable: true, ..
-                            })
-                            | Some(IsNullable {
-                                content: Primitive::Interface(_),
-                                ..
-                            }) => Type::named(&content).required(),
-                            Some(IsNullable {
-                                content: Primitive::String,
-                                ..
-                            }) => Type::string().required(),
-                            Some(IsNullable {
-                                content: Primitive::IdentifierName,
-                                ..
-                            }) => Type::identifier_name().required(),
-                            Some(IsNullable {
-                                content: Primitive::PropertyKey,
-                                ..
-                            }) => Type::property_key().required(),
-                            Some(IsNullable {
-                                content: Primitive::Number,
-                                ..
-                            }) => Type::number().required(),
-                            Some(IsNullable {
-                                content: Primitive::UnsignedLong,
-                                ..
-                            }) => Type::unsigned_long().required(),
-                            Some(IsNullable {
-                                content: Primitive::Boolean,
-                                ..
-                            }) => Type::bool().required(),
-                            Some(IsNullable {
-                                content: Primitive::Offset,
-                                ..
-                            }) => Type::offset().required(),
-                            Some(IsNullable {
-                                content: Primitive::Void,
-                                ..
-                            }) => Type::void().required(),
-                        };
-                        debug!(target: "export_utils", "import_typespec aliasing {:?} => {:?}",
-                            my_name, deanonymized);
-                        if let Some(ref mut typedef) = self.builder.add_typedef(&my_name) {
-                            debug!(target: "export_utils", "import_typespec: Defining {name} (name to content)", name = my_name.to_str());
-                            typedef.with_type(deanonymized.clone());
-                        } else {
-                            debug!(target: "export_utils", "import_typespec: Attempting to redefine typedef {name}", name = my_name.to_str());
-                        }
-                    }
-                    // Also, don't forget to copy the typedef and alias `link`
-                    let deanonymized = Type::named(link).required();
-                    if let Some(ref mut typedef) = self.builder.add_typedef(&my_name) {
-                        debug!(target: "export_utils", "import_typespec: Defining {name} (name to link)", name = my_name.to_str());
-                        typedef.with_type(deanonymized.clone());
-                    } else {
-                        debug!(target: "export_utils", "import_typespec: Attempting to redefine typedef {name}", name = my_name.to_str());
-                    }
-                }
-                (sum, link.clone())
-            }
-            TypeSpec::Array {
-                ref contents,
-                ref supports_empty,
-            } => {
-                let (_, contents_name) = self.import_type(spec, contents, None);
-                let my_name = match public_name {
-                    None => self.builder.node_name(&format!(
-                        "{non_empty}ListOf{content}",
-                        non_empty = if *supports_empty { "" } else { "NonEmpty" },
-                        content = contents_name.to_str()
-                    )),
-                    Some(ref name) => name.clone(),
-                };
-                let deanonymized = if *supports_empty {
-                    Type::named(&contents_name).array()
-                } else {
-                    Type::named(&contents_name).non_empty_array()
-                };
-                if let Some(ref mut typedef) = self.builder.add_typedef(&my_name) {
-                    debug!(target: "export_utils", "import_typespec: Defining {name} (name to list)",
-                        name = my_name.to_str());
-                    typedef.with_type(deanonymized.clone());
-                } else {
-                    debug!(target: "export_utils", "import_typespec: Attempting to redefine typedef {name}", name = my_name.to_str());
-                }
-                (None, my_name)
-            }
-            TypeSpec::TypeSum(ref sum) => {
-                let mut full_sum = HashSet::new();
-                let mut names = vec![];
-                let mut subsums = vec![];
-                for sub_type in sum.types() {
-                    let (sub_sum, name) = self.import_typespec(spec, sub_type, None);
-                    let mut sub_sum = sub_sum.unwrap_or_else(
-                        || panic!("While treating {:?}, attempting to create a sum containing {}, which isn't an interface or a sum of interfaces", type_spec, name)
-                    );
-                    if sub_sum.len() > 1 {
-                        // The subtype is itself a sum.
-                        subsums.push(name.clone())
-                    }
-                    names.push(name);
-                    for item in sub_sum.drain() {
-                        full_sum.insert(item);
-                    }
-                }
-                let my_name = match public_name {
-                    None => self.builder.node_name(&format!(
-                        "{}",
-                        names.into_iter().sorted().into_iter().format("Or")
-                    )),
-                    Some(ref name) => name.clone(),
-                };
-                for subsum_name in subsums {
-                    // So, `my_name` is a superset of `subsum_name`.
-                    let supersum_entry = self
-                        .supersums_of
-                        .entry(subsum_name.clone())
-                        .or_insert_with(|| HashSet::new());
-                    supersum_entry.insert(my_name.clone());
-                }
-                let sum: Vec<_> = full_sum.iter().map(Type::named).collect();
-                let deanonymized = Type::sum(&sum).required();
-                if let Some(ref mut typedef) = self.builder.add_typedef(&my_name) {
-                    debug!(target: "export_utils", "import_typespec: Defining {name} (name to sum)", name = my_name.to_str());
-                    typedef.with_type(deanonymized.clone());
-                } else {
-                    debug!(target: "export_utils", "import_type: Attempting to redefine typedef {name}", name = my_name.to_str());
-                }
-                (Some(full_sum), my_name)
-            }
-        }
-    }
-}
-
-/// Utility to give a name to a type or type spec.
-pub struct TypeName;
-impl TypeName {
-    pub fn type_(type_: &Type) -> String {
-        let spec_name = Self::type_spec(type_.spec());
-        if type_.is_optional() {
-            format!("Optional{}", spec_name)
-        } else {
-            spec_name
-        }
-    }
-
-    pub fn type_spec(spec: &TypeSpec) -> String {
-        match *spec {
-            TypeSpec::Array {
-                ref contents,
-                supports_empty: false,
-            } => format!("NonEmptyListOf{}", Self::type_(contents)),
-            TypeSpec::Array {
-                ref contents,
-                supports_empty: true,
-            } => format!("ListOf{}", Self::type_(contents)),
-            TypeSpec::NamedType(ref name) => name.to_string().clone(),
-            TypeSpec::Offset => "_Offset".to_string(),
-            TypeSpec::Boolean => "_Bool".to_string(),
-            TypeSpec::Number => "_Number".to_string(),
-            TypeSpec::UnsignedLong => "_UnsignedLong".to_string(),
-            TypeSpec::String => "_String".to_string(),
-            TypeSpec::Void => "_Void".to_string(),
-            TypeSpec::IdentifierName => "IdentifierName".to_string(),
-            TypeSpec::PropertyKey => "PropertyKey".to_string(),
-            TypeSpec::TypeSum(ref sum) => format!(
-                "{}",
-                sum.types()
-                    .iter()
-                    .map(Self::type_spec)
-                    .sorted()
-                    .into_iter()
-                    .format("Or")
-            ),
-        }
-    }
-}
-
-/// Export a type specification as webidl.
-///
-/// Designed for generating documentation.
-pub struct ToWebidl;
-impl ToWebidl {
-    /// Export a TypeSpec.
-    pub fn spec(spec: &TypeSpec, prefix: &str, indent: &str) -> Option<String> {
-        let result = match *spec {
-            TypeSpec::Offset => {
-                return None;
-            }
-            TypeSpec::Array {
-                ref contents,
-                ref supports_empty,
-            } => match Self::type_(&*contents, prefix, indent) {
-                None => {
-                    return None;
-                }
-                Some(description) => format!(
-                    "{emptiness}FrozenArray<{}>",
-                    description,
-                    emptiness = if *supports_empty { "" } else { "[NonEmpty] " }
-                ),
-            },
-            TypeSpec::Boolean => "bool".to_string(),
-            TypeSpec::String => "string".to_string(),
-            TypeSpec::PropertyKey => "[PropertyKey] string".to_string(),
-            TypeSpec::IdentifierName => "[IdentifierName] string".to_string(),
-            TypeSpec::Number => "number".to_string(),
-            TypeSpec::UnsignedLong => "unsigned long".to_string(),
-            TypeSpec::NamedType(ref name) => name.to_str().to_string(),
-            TypeSpec::TypeSum(ref sum) => format!(
-                "({})",
-                sum.types()
-                    .iter()
-                    .filter_map(|x| Self::spec(x, "", indent))
-                    .format(" or ")
-            ),
-            TypeSpec::Void => "void".to_string(),
-        };
-        Some(result)
-    }
-
-    /// Export a Type
-    pub fn type_(type_: &Type, prefix: &str, indent: &str) -> Option<String> {
-        let pretty_type = Self::spec(type_.spec(), prefix, indent);
-        match pretty_type {
-            None => None,
-            Some(pretty_type) => Some(format!(
-                "{}{}",
-                pretty_type,
-                if type_.is_optional() { "?" } else { "" }
-            )),
-        }
-    }
-
-    /// Export an Interface
-    pub fn interface(interface: &Interface, prefix: &str, indent: &str) -> String {
-        let mut result = format!(
-            "{prefix} interface {name} : Node {{\n",
-            prefix = prefix,
-            name = interface.name().to_str()
-        );
-        {
-            let prefix = format!("{prefix}{indent}", prefix = prefix, indent = indent);
-            for field in interface.contents().fields() {
-                match Self::type_(field.type_(), &prefix, indent) {
-                    None =>
-                        /* generated field, ignore */
-                        {}
-                    Some(description) => {
-                        if let Some(ref doc) = field.doc() {
-                            result.push_str(&format!(
-                                "{prefix}// {doc}\n",
-                                prefix = prefix,
-                                doc = doc
-                            ));
-                        }
-                        result.push_str(&format!(
-                            "{prefix}{description} {name};\n",
-                            prefix = prefix,
-                            name = field.name().to_str(),
-                            description = description
-                        ));
-                        if field.doc().is_some() {
-                            result.push_str("\n");
-                        }
-                    }
-                }
-            }
-        }
-        result.push_str(&format!("{prefix} }}\n", prefix = prefix));
-        result
-    }
-}
diff --git a/third_party/rust/binjs_meta/src/import.rs b/third_party/rust/binjs_meta/src/import.rs
deleted file mode 100644
index 329b139177..0000000000
--- a/third_party/rust/binjs_meta/src/import.rs
+++ /dev/null
@@ -1,358 +0,0 @@
-use spec::{self, Laziness, SpecBuilder, TypeSpec, TypeSum};
-use weedle::common::Identifier;
-use weedle::types::*;
-use weedle::*;
-
-fn nullable<T: std::fmt::Debug>(src: &MayBeNull<T>, dst: TypeSpec) -> spec::Type {
-    if src.q_mark.is_some() {
-        dst.optional()
-            .unwrap_or_else(|| panic!("This type could not be made optional {:?}", src.type_))
-    } else {
-        dst.required()
-    }
-}
-
-pub struct Importer {
-    builder: SpecBuilder,
-    /// The interfaces we have traversed so far.
-    path: Vec<String>,
-}
-
-impl Importer {
-    /// Import a WebIDL spec into a SpecBuilder.
-    ///
-    /// A WebIDL spec may consist in several files. Files are parsed in the order
-    /// of `sources`. An extension file (e.g. `es6-extended.webidl`) MUST appear
-    /// after the files it extends.
-    ///
-    /// ```
-    /// extern crate binjs_meta;
-    /// use binjs_meta::spec::SpecOptions;
-    ///
-    /// let mut builder = binjs_meta::import::Importer::import(vec!["
-    ///    interface FooContents {
-    ///      attribute boolean value;
-    ///    };
-    ///    interface LazyFoo {
-    ///       [Lazy] attribute FooContents contents;
-    ///    };
-    ///    interface EagerFoo {
-    ///       attribute FooContents contents;
-    ///    };
-    /// "].into_iter()).expect("Could not parse");
-    ///
-    /// let fake_root = builder.node_name("@@ROOT@@"); // Unused
-    /// let null = builder.node_name(""); // Used
-    /// let spec = builder.into_spec(SpecOptions {
-    ///     root: &fake_root,
-    ///     null: &null,
-    /// });
-    ///
-    /// let name_eager = spec.get_node_name("EagerFoo")
-    ///     .expect("Missing name EagerFoo");
-    /// let name_lazy = spec.get_node_name("LazyFoo")
-    ///     .expect("Missing name LazyFoo");
-    /// let name_contents = spec.get_field_name("contents")
-    ///     .expect("Missing name contents");
-    ///
-    /// {
-    ///     let interface_eager = spec.get_interface_by_name(&name_eager)
-    ///         .expect("Missing interface EagerFoo");
-    ///     let contents_field =
-    ///         interface_eager.get_field_by_name(&name_contents)
-    ///         .expect("Missing field contents");
-    ///     assert_eq!(contents_field.is_lazy(), false);
-    /// }
-    ///
-    /// {
-    ///     let interface_lazy = spec.get_interface_by_name(&name_lazy)
-    ///         .expect("Missing interface LazyFoo");
-    ///     let contents_field =
-    ///         interface_lazy.get_field_by_name(&name_contents)
-    ///         .expect("Missing field contents");
-    ///     assert_eq!(contents_field.is_lazy(), true);
-    /// }
-    /// ```
-    pub fn import<'a>(
-        sources: impl IntoIterator<Item = &'a str>,
-    ) -> Result<SpecBuilder, weedle::Err<(&'a str, ErrorKind)>> {
-        let mut importer = Importer {
-            path: Vec::with_capacity(256),
-            builder: SpecBuilder::new(),
-        };
-        for source in sources {
-            let ast = weedle::parse(source)?;
-            importer.import_all_definitions(&ast);
-        }
-        Ok(importer.builder)
-    }
-
-    fn import_all_definitions(&mut self, ast: &Definitions) {
-        for definition in ast {
-            self.import_definition(&definition)
-        }
-    }
-
-    fn import_definition(&mut self, def: &Definition) {
-        match *def {
-            Definition::Enum(ref enum_) => self.import_enum(enum_),
-            Definition::Typedef(ref typedef) => self.import_typedef(typedef),
-            Definition::Interface(ref interface) => self.import_interface(interface),
-            _ => panic!("Not implemented: importing {:?}", def),
-        }
-    }
-
-    fn import_enum(&mut self, enum_: &EnumDefinition) {
-        let name = self.builder.node_name(enum_.identifier.0);
-        let mut node = self
-            .builder
-            .add_string_enum(&name)
-            .expect("Name already present");
-        for variant in &enum_.values.body.list {
-            node.with_string(&variant.0);
-        }
-    }
-
-    fn import_typedef(&mut self, typedef: &TypedefDefinition) {
-        let name = self.builder.node_name(typedef.identifier.0);
-        // The following are, unfortunately, not true typedefs.
-        // Ignore their definition.
-        let type_ = match typedef.identifier.0 {
-            "Identifier" => TypeSpec::IdentifierName.required(),
-            "IdentifierName" => TypeSpec::IdentifierName.required(),
-            "PropertyKey" => TypeSpec::PropertyKey.required(),
-            _ => self.convert_type(&typedef.type_.type_),
-        };
-        debug!(target: "meta::import", "Importing typedef {type_:?} {name:?}",
-            type_ = type_,
-            name = name);
-        let mut node = self.builder.add_typedef(&name).unwrap_or_else(|| {
-            panic!(
-                "Error: Name {} is defined more than once in the spec.",
-                name
-            )
-        });
-        assert!(!type_.is_optional());
-        node.with_spec(type_.spec);
-    }
-
-    fn import_interface(&mut self, interface: &InterfaceDefinition) {
-        // Handle special, hardcoded, interfaces.
-        match interface.identifier.0 {
-            "Node" => {
-                // We're not interested in the root interface.
-                return;
-            }
-            "IdentifierName" => unimplemented!(),
-            _ => {}
-        }
-        if let Some(ref parent) = interface.inheritance {
-            assert_eq!(parent.identifier.0, "Node");
-        }
-
-        self.path.push(interface.identifier.0.to_owned());
-
-        // Now handle regular stuff.
-        let mut fields = Vec::new();
-        for member in &interface.members.body {
-            if let interface::InterfaceMember::Attribute(interface::AttributeInterfaceMember {
-                modifier: None,
-                attributes,
-                identifier,
-                type_,
-                ..
-            }) = member
-            {
-                let name = self.builder.field_name(identifier.0);
-                let type_ = self.convert_type(&type_.type_);
-
-                let is_lazy = attributes
-                    .iter()
-                    .flat_map(|attribute| &attribute.body.list)
-                    .find(|attribute| match attribute {
-                        attribute::ExtendedAttribute::NoArgs(
-                            attribute::ExtendedAttributeNoArgs(Identifier("Lazy")),
-                        ) => true,
-                        _ => false,
-                    })
-                    .is_some();
-
-                fields.push((
-                    name,
-                    type_,
-                    if is_lazy {
-                        Laziness::Lazy
-                    } else {
-                        Laziness::Eager
-                    },
-                ));
-            } else {
-                panic!("Expected an attribute, got {:?}", member);
-            }
-        }
-        let name = self.builder.node_name(interface.identifier.0);
-
-        // Set to `Some("Foo")` if this interface has attribute
-        // `[ExtendsTypeSum=Foo]`.
-        let mut extends_type_sum = None;
-        let mut scoped_dictionary = None;
-        {
-            let mut node = self
-                .builder
-                .add_interface(&name)
-                .expect("Name already present");
-            for (field_name, field_type, laziness) in fields.drain(..) {
-                node.with_field_laziness(&field_name, field_type, laziness);
-            }
-
-            for attribute in interface
-                .attributes
-                .iter()
-                .flat_map(|attribute| &attribute.body.list)
-            {
-                use weedle::attribute::ExtendedAttribute::*;
-                use weedle::attribute::*;
-                match *attribute {
-                    NoArgs(ExtendedAttributeNoArgs(Identifier("Skippable"))) => {
-                        panic!("Encountered deprecated attribute [Skippable]");
-                    }
-                    NoArgs(ExtendedAttributeNoArgs(Identifier("Scope"))) => {
-                        node.with_scope(true);
-                    }
-                    Ident(ExtendedAttributeIdent {
-                        lhs_identifier: Identifier("ExtendsTypeSum"),
-                        assign: _,
-                        rhs: IdentifierOrString::Identifier(ref rhs),
-                    }) => {
-                        assert!(extends_type_sum.is_none());
-                        extends_type_sum = Some(rhs.0);
-                    }
-                    Ident(ExtendedAttributeIdent {
-                        lhs_identifier: Identifier("ScopedDictionary"),
-                        assign: _,
-                        rhs: IdentifierOrString::Identifier(ref rhs),
-                    }) => {
-                        assert!(scoped_dictionary.is_none());
-                        scoped_dictionary = Some(rhs.0);
-                    }
-                    _ => panic!("Unknown attribute {:?}", attribute),
-                }
-            }
-
-            // If the node contains an attribute `[ScopedDictionary=field]`,
-            // mark the node as inserting a scoped dictionary with this field.
-            if let Some(ref field_name) = scoped_dictionary {
-                node.with_scoped_dictionary_str(field_name);
-            }
-        }
-
-        // If the node contains an attribute `[ExtendsTypeSum=Foobar]`,
-        // extend `typedef (... or ... or ...) Foobar` into
-        // `typedef (... or ... or ... or CurrentNode) Foobar`.
-        if let Some(ref extended) = extends_type_sum {
-            let node_name = self
-                .builder
-                .get_node_name(extended)
-                .unwrap_or_else(|| panic!("Could not find node name {}", extended));
-            let mut typedef = self
-                .builder
-                .get_typedef_mut(&node_name)
-                .unwrap_or_else(|| panic!("Could not find typedef {}", extended));
-            let typespec = typedef.spec_mut();
-            let typesum = if let TypeSpec::TypeSum(ref mut typesum) = *typespec {
-                typesum
-            } else {
-                panic!(
-                    "Attempting to extend a node that is not a type sum {}",
-                    extended
-                );
-            };
-            typesum.with_type_case(TypeSpec::NamedType(name));
-        }
-
-        self.path.pop();
-    }
-
-    fn convert_single_type(&mut self, t: &NonAnyType) -> spec::Type {
-        match t {
-            NonAnyType::Boolean(ref b) => nullable(b, TypeSpec::Boolean),
-            NonAnyType::Identifier(ref id) => nullable(id, {
-                let name = self.builder.node_name(id.type_.0);
-                // Sadly, some identifiers are not truly `typedef`s.
-                match name.to_str() {
-                    "IdentifierName" if self.is_at_interface("StaticMemberAssignmentTarget") => {
-                        TypeSpec::PropertyKey
-                    }
-                    "IdentifierName" if self.is_at_interface("StaticMemberExpression") => {
-                        TypeSpec::PropertyKey
-                    }
-                    "IdentifierName" if self.is_at_interface("ImportSpecifier") => {
-                        TypeSpec::PropertyKey
-                    }
-                    "IdentifierName" if self.is_at_interface("ExportSpecifier") => {
-                        TypeSpec::PropertyKey
-                    }
-                    "IdentifierName" if self.is_at_interface("ExportLocalSpecifier") => {
-                        TypeSpec::PropertyKey
-                    }
-                    "IdentifierName" => TypeSpec::IdentifierName,
-                    "Identifier" => TypeSpec::IdentifierName,
-                    _ => TypeSpec::NamedType(name.clone()),
-                }
-            }),
-            NonAnyType::DOMString(ref s) => nullable(
-                s,
-                if self.is_at_interface("LiteralPropertyName") {
-                    TypeSpec::PropertyKey
-                } else {
-                    TypeSpec::String
-                },
-            ),
-            NonAnyType::FrozenArrayType(ref t) => nullable(
-                t,
-                TypeSpec::Array {
-                    contents: Box::new(self.convert_type(&t.type_.generics.body)),
-                    supports_empty: true,
-                },
-            ),
-            NonAnyType::FloatingPoint(ref t) => nullable(t, TypeSpec::Number),
-            NonAnyType::Integer(ref t) => nullable(t, TypeSpec::UnsignedLong),
-            _ => {
-                panic!("I don't know how to import {:?} yet", t);
-            }
-        }
-    }
-
-    fn convert_union_type(&mut self, types: &MayBeNull<UnionType>) -> spec::Type {
-        let converted_types: Vec<_> = types
-            .type_
-            .body
-            .list
-            .iter()
-            .map(|t| match t {
-                UnionMemberType::Single(AttributedNonAnyType { type_: t, .. }) => {
-                    self.convert_single_type(t)
-                }
-                UnionMemberType::Union(t) => self.convert_union_type(t),
-            })
-            .map(|t| t.spec)
-            .collect();
-
-        nullable(types, TypeSpec::TypeSum(TypeSum::new(converted_types)))
-    }
-
-    fn convert_type(&mut self, t: &Type) -> spec::Type {
-        match t {
-            Type::Single(SingleType::NonAny(t)) => self.convert_single_type(t),
-            Type::Union(types) => self.convert_union_type(types),
-            _ => panic!("I don't know how to import {:?} yet", t),
-        }
-    }
-
-    fn is_at_interface(&self, name: &str) -> bool {
-        if self.path.len() == 0 {
-            return false;
-        }
-        self.path[0].as_str() == name
-    }
-}
diff --git a/third_party/rust/binjs_meta/src/lib.rs b/third_party/rust/binjs_meta/src/lib.rs
deleted file mode 100644
index 1c96ebbc19..0000000000
--- a/third_party/rust/binjs_meta/src/lib.rs
+++ /dev/null
@@ -1,21 +0,0 @@
-//! This crate offers tools designed to aid with the implementation
-//! of the JavaScript syntax and BinAST encoders/decoders/manipulators.
-
-extern crate inflector;
-extern crate itertools;
-
-#[macro_use]
-extern crate log;
-extern crate weedle;
-
-/// Generic tools for generating implementations of the Syntax.
-pub mod export;
-
-/// Import a specification of the Syntax.
-pub mod import;
-
-/// Manipulating the specifications of the language.
-pub mod spec;
-
-/// Misc. utilities.
-pub mod util;
diff --git a/third_party/rust/binjs_meta/src/spec.rs b/third_party/rust/binjs_meta/src/spec.rs
deleted file mode 100644
index 7f410a0a4c..0000000000
--- a/third_party/rust/binjs_meta/src/spec.rs
+++ /dev/null
@@ -1,1209 +0,0 @@
-//! Definition of a spec for a version (or subset) of JavaScript.
-
-pub use util::ToStr;
-
-use itertools::Itertools;
-
-use std;
-use std::cell::*;
-use std::collections::{HashMap, HashSet};
-use std::fmt::{Debug, Display};
-use std::hash::*;
-use std::rc::*;
-
-/// Whether an attribute is eager or lazy.
-#[derive(Clone, Debug, PartialEq, Eq)]
-pub enum Laziness {
-    /// An eager attribute is designed to be parsed immediately.
-    Eager,
-    /// A lazy attribute is designed for deferred parsing.
-    Lazy,
-}
-
-/// The name of an interface or enum.
-#[derive(Clone, Hash, PartialEq, Eq, PartialOrd, Ord)]
-pub struct NodeName(Rc<String>);
-impl NodeName {
-    pub fn to_string(&self) -> &String {
-        self.0.as_ref()
-    }
-    pub fn to_str(&self) -> &str {
-        self.0.as_ref()
-    }
-    pub fn to_rc_string(&self) -> &Rc<String> {
-        &self.0
-    }
-}
-impl Debug for NodeName {
-    fn fmt(&self, formatter: &mut std::fmt::Formatter) -> Result<(), std::fmt::Error> {
-        Debug::fmt(self.to_str(), formatter)
-    }
-}
-impl Display for NodeName {
-    fn fmt(&self, formatter: &mut std::fmt::Formatter) -> Result<(), std::fmt::Error> {
-        Display::fmt(self.to_str(), formatter)
-    }
-}
-impl ToStr for NodeName {
-    fn to_str(&self) -> &str {
-        &self.0
-    }
-}
-
-/// The name of a field in an interface.
-#[derive(Clone, Hash, PartialEq, Eq, PartialOrd, Ord)]
-pub struct FieldName(Rc<String>);
-impl FieldName {
-    pub fn to_string(&self) -> &String {
-        self.0.as_ref()
-    }
-    pub fn to_rc_string(&self) -> &Rc<String> {
-        &self.0
-    }
-}
-impl Debug for FieldName {
-    fn fmt(&self, formatter: &mut std::fmt::Formatter) -> Result<(), std::fmt::Error> {
-        Debug::fmt(self.to_str(), formatter)
-    }
-}
-impl ToStr for FieldName {
-    fn to_str(&self) -> &str {
-        self.0.as_ref()
-    }
-}
-
-/// An enumeration of strings.
-///
-/// A valid value is any of these strings.
-#[derive(Debug)]
-pub struct StringEnum {
-    name: NodeName,
-    // Invariant: values are distinct // FIXME: Not checked yet.
-    values: Vec<String>,
-}
-
-/// An enumeration of interfaces.
-#[derive(Clone, Debug, PartialEq, Eq)] // FIXME: Get rid of Eq
-pub struct TypeSum {
-    types: Vec<TypeSpec>,
-    /// Once we have called `into_spec`, this is guaranteed to resolve
-    /// to at least one Interface.
-    interfaces: HashSet<NodeName>,
-}
-impl TypeSum {
-    pub fn new(types: Vec<TypeSpec>) -> Self {
-        TypeSum {
-            types,
-            interfaces: HashSet::new(),
-        }
-    }
-    pub fn types(&self) -> &[TypeSpec] {
-        &self.types
-    }
-    pub fn types_mut(&mut self) -> &mut [TypeSpec] {
-        &mut self.types
-    }
-    pub fn interfaces(&self) -> &HashSet<NodeName> {
-        &self.interfaces
-    }
-    pub fn get_interface(&self, spec: &Spec, name: &NodeName) -> Option<Rc<Interface>> {
-        debug!(target: "spec", "get_interface, looking for {:?} in sum {:?}", name, self);
-        for item in &self.types {
-            let result = item.get_interface(spec, name);
-            if result.is_some() {
-                return result;
-            }
-        }
-        None
-    }
-
-    /// Add a new type case to this sum.
-    pub fn with_type_case(&mut self, spec: TypeSpec) -> &mut Self {
-        debug_assert_eq!(self.interfaces.len(), 0);
-        self.types.push(spec);
-        self
-    }
-}
-
-/// Representation of a field in an interface.
-#[derive(Clone, PartialEq, Eq, Debug)]
-pub struct Field {
-    /// The name of the field.
-    name: FieldName,
-
-    /// The type of the field.
-    type_: Type,
-
-    /// Documentation for the field. Ignored for the time being.
-    documentation: Option<String>,
-
-    laziness: Laziness,
-}
-impl Hash for Field {
-    fn hash<H>(&self, state: &mut H)
-    where
-        H: Hasher,
-    {
-        self.name.hash(state)
-    }
-}
-impl Field {
-    pub fn new(name: FieldName, type_: Type) -> Self {
-        Field {
-            name,
-            type_,
-            documentation: None,
-            laziness: Laziness::Eager,
-        }
-    }
-    pub fn name(&self) -> &FieldName {
-        &self.name
-    }
-    pub fn type_(&self) -> &Type {
-        &self.type_
-    }
-    pub fn is_lazy(&self) -> bool {
-        self.laziness == Laziness::Lazy
-    }
-    pub fn laziness(&self) -> Laziness {
-        self.laziness.clone()
-    }
-    pub fn with_laziness(mut self, laziness: Laziness) -> Self {
-        self.laziness = laziness;
-        self
-    }
-    pub fn doc(&self) -> Option<&str> {
-        match self.documentation {
-            None => None,
-            Some(ref s) => Some(&*s),
-        }
-    }
-    pub fn with_doc(mut self, doc: Option<String>) -> Self {
-        self.documentation = doc;
-        self
-    }
-}
-
-/// The contents of a type, typically that of a field.
-///
-/// Note that we generally use `Type`, to represent
-/// the fact that some fields accept `null` while
-/// others do not.
-#[derive(Clone, Debug, PartialEq, Eq)]
-pub enum TypeSpec {
-    /// An array of values of the same type.
-    Array {
-        /// The type of values in the array.
-        contents: Box<Type>,
-
-        /// If `true`, the array may be empty.
-        supports_empty: bool,
-    },
-
-    NamedType(NodeName),
-
-    TypeSum(TypeSum),
-
-    /// A boolean.
-    Boolean,
-
-    /// A string.
-    String,
-
-    /// A number, as per JavaScript specifications.
-    Number,
-
-    UnsignedLong,
-
-    /// A number of bytes in the binary file.
-    ///
-    /// This spec is used only internally, as a hidden
-    /// field injected by deanonymization, to represent
-    /// lazy fields.
-    Offset,
-
-    /// Nothing.
-    ///
-    /// For the moment, this spec is used only internally.
-    Void,
-
-    /// A string used to represent something bound in a scope (i.e. a variable, but not a property).
-    /// At this level, we make no distinction between `Identifier` and `IdentifierName`.
-    ///
-    /// Actually maps to a subset of `IdentifierName` in webidl.
-    IdentifierName,
-
-    /// A key for a property. For the time being, we make no distinction between variants such
-    /// as `LiteralPropertyName` and `IdentifierName`-as-property-keys.
-    PropertyKey,
-}
-
-#[derive(Clone, Debug)]
-pub enum NamedType {
-    Interface(Rc<Interface>),
-    Typedef(Rc<Type>), // FIXME: Check that there are no cycles.
-    StringEnum(Rc<StringEnum>),
-}
-
-impl NamedType {
-    pub fn as_interface(&self, spec: &Spec) -> Option<Rc<Interface>> {
-        match *self {
-            NamedType::Interface(ref result) => Some(result.clone()),
-            NamedType::Typedef(ref type_) => {
-                if let TypeSpec::NamedType(ref named) = *type_.spec() {
-                    let named = spec.get_type_by_name(named).expect("Type not found");
-                    named.as_interface(spec)
-                } else {
-                    None
-                }
-            }
-            NamedType::StringEnum(_) => None,
-        }
-    }
-}
-
-impl TypeSpec {
-    pub fn array(self) -> Type {
-        TypeSpec::Array {
-            contents: Box::new(Type {
-                spec: self,
-                or_null: false,
-            }),
-            supports_empty: true,
-        }
-        .required()
-    }
-
-    pub fn non_empty_array(self) -> Type {
-        TypeSpec::Array {
-            contents: Box::new(Type {
-                spec: self,
-                or_null: false,
-            }),
-            supports_empty: false,
-        }
-        .required()
-    }
-
-    pub fn optional(self) -> Option<Type> {
-        if let TypeSpec::Offset = self {
-            None
-        } else {
-            Some(Type {
-                spec: self,
-                or_null: true,
-            })
-        }
-    }
-
-    pub fn required(self) -> Type {
-        Type {
-            spec: self,
-            or_null: false,
-        }
-    }
-
-    fn typespecs<'a>(&'a self) -> Vec<&'a TypeSpec> {
-        let mut result = Vec::new();
-        let mut stack = vec![self];
-        while let Some(current) = stack.pop() {
-            result.push(current);
-            match *current {
-                TypeSpec::Array { ref contents, .. } => {
-                    stack.push(contents.spec());
-                }
-                TypeSpec::TypeSum(ref sum) => {
-                    for item in sum.types() {
-                        stack.push(item)
-                    }
-                }
-                _ => {}
-            }
-        }
-        result
-    }
-
-    pub fn typenames<'a>(&'a self) -> HashSet<&'a NodeName> {
-        let mut result = HashSet::new();
-        for spec in self.typespecs() {
-            if let TypeSpec::NamedType(ref name) = *spec {
-                result.insert(name);
-            }
-        }
-        result
-    }
-
-    pub fn get_primitive(&self, spec: &Spec) -> Option<IsNullable<Primitive>> {
-        match *self {
-            TypeSpec::Boolean => Some(IsNullable::non_nullable(Primitive::Boolean)),
-            TypeSpec::Void => Some(IsNullable::non_nullable(Primitive::Void)),
-            TypeSpec::Number => Some(IsNullable::non_nullable(Primitive::Number)),
-            TypeSpec::UnsignedLong => Some(IsNullable::non_nullable(Primitive::UnsignedLong)),
-            TypeSpec::String => Some(IsNullable::non_nullable(Primitive::String)),
-            TypeSpec::Offset => Some(IsNullable::non_nullable(Primitive::Offset)),
-            TypeSpec::IdentifierName => Some(IsNullable::non_nullable(Primitive::IdentifierName)),
-            TypeSpec::PropertyKey => Some(IsNullable::non_nullable(Primitive::PropertyKey)),
-            TypeSpec::NamedType(ref name) => match spec.get_type_by_name(name).unwrap() {
-                NamedType::Interface(ref interface) => Some(IsNullable::non_nullable(
-                    Primitive::Interface(interface.clone()),
-                )),
-                NamedType::Typedef(ref type_) => type_.get_primitive(spec),
-                NamedType::StringEnum(_) => None,
-            },
-            _ => None,
-        }
-    }
-}
-
-#[derive(Debug)]
-pub struct IsNullable<T> {
-    pub is_nullable: bool,
-    pub content: T,
-}
-impl<T> IsNullable<T> {
-    fn non_nullable(value: T) -> Self {
-        IsNullable {
-            is_nullable: false,
-            content: value,
-        }
-    }
-}
-
-#[derive(Debug)]
-pub enum Primitive {
-    String,
-    Boolean,
-    Void,
-    Number,
-    UnsignedLong,
-    Offset,
-    Interface(Rc<Interface>),
-    IdentifierName,
-    PropertyKey,
-}
-
-#[derive(Clone, Debug, PartialEq)]
-pub struct Type {
-    pub spec: TypeSpec,
-    or_null: bool,
-}
-impl Eq for Type {}
-
-impl Type {
-    pub fn or_null(&mut self) -> &mut Self {
-        self.or_null = true;
-        self
-    }
-
-    pub fn with_spec(&mut self, spec: TypeSpec) -> &mut Self {
-        self.spec = spec;
-        self
-    }
-
-    pub fn with_type(&mut self, type_: Type) -> &mut Self {
-        self.spec = type_.spec;
-        self.or_null = type_.or_null;
-        self
-    }
-
-    pub fn spec(&self) -> &TypeSpec {
-        &self.spec
-    }
-    pub fn spec_mut(&mut self) -> &mut TypeSpec {
-        &mut self.spec
-    }
-    pub fn is_optional(&self) -> bool {
-        self.or_null
-    }
-
-    /// Shorthand constructors.
-    pub fn named(name: &NodeName) -> TypeSpec {
-        TypeSpec::NamedType(name.clone())
-    }
-    pub fn sum(types: &[TypeSpec]) -> TypeSpec {
-        let specs = types.iter().cloned().collect();
-        TypeSpec::TypeSum(TypeSum::new(specs))
-    }
-    pub fn string() -> TypeSpec {
-        TypeSpec::String
-    }
-    pub fn number() -> TypeSpec {
-        TypeSpec::Number
-    }
-    pub fn unsigned_long() -> TypeSpec {
-        TypeSpec::UnsignedLong
-    }
-    pub fn bool() -> TypeSpec {
-        TypeSpec::Boolean
-    }
-    pub fn void() -> TypeSpec {
-        TypeSpec::Void
-    }
-    pub fn identifier_name() -> TypeSpec {
-        TypeSpec::IdentifierName
-    }
-    pub fn property_key() -> TypeSpec {
-        TypeSpec::PropertyKey
-    }
-
-    /// An `offset` type, holding a number of bytes in the binary file.
-    pub fn offset() -> TypeSpec {
-        TypeSpec::Offset
-    }
-
-    pub fn array(self) -> TypeSpec {
-        TypeSpec::Array {
-            contents: Box::new(self),
-            supports_empty: true,
-        }
-    }
-
-    pub fn non_empty_array(self) -> TypeSpec {
-        TypeSpec::Array {
-            contents: Box::new(self),
-            supports_empty: false,
-        }
-    }
-
-    pub fn get_primitive(&self, spec: &Spec) -> Option<IsNullable<Primitive>> {
-        if let Some(mut primitive) = self.spec.get_primitive(spec) {
-            primitive.is_nullable = primitive.is_nullable || self.or_null;
-            Some(primitive)
-        } else {
-            None
-        }
-    }
-}
-
-/// Representation of an object, i.e. a set of fields.
-///
-/// Field order is *not* specified, but is expected to remain stable during encoding
-/// operations and during decoding operations. Note in particular that the order may
-/// change between encoding and decoding.
-#[derive(Clone, Debug)]
-pub struct Obj {
-    fields: Vec<Field>,
-}
-impl PartialEq for Obj {
-    fn eq(&self, other: &Self) -> bool {
-        // Normalize order before comparing.
-        let me: HashSet<_> = self.fields.iter().collect();
-        let other: HashSet<_> = other.fields.iter().collect();
-        me == other
-    }
-}
-impl Eq for Obj {}
-
-impl Obj {
-    /// Create a new empty structure
-    pub fn new() -> Self {
-        Obj { fields: Vec::new() }
-    }
-    /// A list of the fields in the structure.
-    pub fn fields<'a>(&'a self) -> &'a [Field] {
-        &self.fields
-    }
-    /// Fetch a specific field in the structure
-    pub fn field<'a>(&'a self, name: &FieldName) -> Option<&'a Field> {
-        self.fields.iter().find(|field| &field.name == name)
-    }
-
-    pub fn with_full_field(&mut self, field: Field) -> &mut Self {
-        if self.field(field.name()).is_some() {
-            warn!("Field: attempting to overwrite {:?}", field.name());
-            return self;
-        }
-        self.fields.push(field);
-        self
-    }
-
-    fn with_field_aux(
-        self,
-        name: &FieldName,
-        type_: Type,
-        laziness: Laziness,
-        doc: Option<&str>,
-    ) -> Self {
-        if self.field(name).is_some() {
-            warn!("Field: attempting to overwrite {:?}", name);
-            return self;
-        }
-        let mut fields = self.fields;
-        fields.push(
-            Field::new(name.clone(), type_)
-                .with_doc(doc.map(str::to_string))
-                .with_laziness(laziness),
-        );
-        Obj { fields }
-    }
-
-    /// Extend a structure with a field.
-    pub fn with_field(self, name: &FieldName, type_: Type) -> Self {
-        self.with_field_aux(name, type_, Laziness::Eager, None)
-    }
-
-    pub fn with_field_doc(self, name: &FieldName, type_: Type, doc: &str) -> Self {
-        self.with_field_aux(name, type_, Laziness::Eager, Some(doc))
-    }
-
-    pub fn with_field_lazy(self, name: &FieldName, type_: Type) -> Self {
-        self.with_field_aux(name, type_, Laziness::Lazy, None)
-    }
-}
-
-impl StringEnum {
-    pub fn name(&self) -> &NodeName {
-        &self.name
-    }
-
-    pub fn strings(&self) -> &[String] {
-        &self.values
-    }
-
-    /// Add a string to the enum. Idempotent.
-    pub fn with_string(&mut self, string: &str) -> &mut Self {
-        let string = string.to_string();
-        if self.values.iter().find(|x| **x == string).is_none() {
-            self.values.push(string.to_string())
-        }
-        self
-    }
-    /// Add several enums to the list. Idempotent.
-    pub fn with_strings(&mut self, strings: &[&str]) -> &mut Self {
-        for string in strings {
-            self.with_string(string);
-        }
-        self
-    }
-}
-
-#[derive(Clone, Debug)]
-pub struct InterfaceDeclaration {
-    /// The name of the interface, e.g. `Node`.
-    name: NodeName,
-
-    /// The contents of this interface, excluding the contents of parent interfaces.
-    contents: Obj,
-
-    is_scope: bool,
-
-    /// If Some(name), this interface introduces a scoped dictionary, i.e. a new
-    /// dictionary that is designed to be used when encoding/decoding its child
-    /// nodes.
-    scoped_dictionary: Option<FieldName>,
-}
-
-impl InterfaceDeclaration {
-    /// A list of the fields in the interface.
-    pub fn fields<'a>(&'a self) -> &'a [Field] {
-        self.contents.fields()
-    }
-    /// Fetch a specific field in the structure
-    pub fn field<'a>(&'a self, name: &FieldName) -> Option<&'a Field> {
-        self.contents.field(name)
-    }
-
-    pub fn with_full_field(&mut self, contents: Field) -> &mut Self {
-        let _ = self.contents.with_full_field(contents);
-        self
-    }
-    pub fn with_field(&mut self, name: &FieldName, type_: Type) -> &mut Self {
-        self.with_field_aux(name, type_, None, Laziness::Eager)
-    }
-    pub fn with_field_lazy(&mut self, name: &FieldName, type_: Type) -> &mut Self {
-        self.with_field_aux(name, type_, None, Laziness::Eager)
-    }
-    pub fn with_field_laziness(
-        &mut self,
-        name: &FieldName,
-        type_: Type,
-        laziness: Laziness,
-    ) -> &mut Self {
-        self.with_field_aux(name, type_, None, laziness)
-    }
-    pub fn with_field_doc(&mut self, name: &FieldName, type_: Type, doc: &str) -> &mut Self {
-        self.with_field_aux(name, type_, Some(doc), Laziness::Eager)
-    }
-    fn with_field_aux(
-        &mut self,
-        name: &FieldName,
-        type_: Type,
-        doc: Option<&str>,
-        laziness: Laziness,
-    ) -> &mut Self {
-        let mut contents = Obj::new();
-        std::mem::swap(&mut self.contents, &mut contents);
-        self.contents = contents.with_field_aux(name, type_, laziness, doc);
-        self
-    }
-    pub fn with_scope(&mut self, value: bool) -> &mut Self {
-        self.is_scope = value;
-        self
-    }
-    pub fn with_scoped_dictionary(&mut self, field_name: &FieldName) -> &mut Self {
-        self.with_scoped_dictionary_str(field_name.to_str())
-    }
-    pub fn with_scoped_dictionary_str(&mut self, field_name: &str) -> &mut Self {
-        let field_name = {
-            self.fields()
-                .into_iter()
-                .map(|field| field.name())
-                .find(|candidate| candidate.to_str() == field_name)
-                .expect("Attempting to set a scoped dictionary with a non-existent field name")
-                .clone()
-        };
-        self.scoped_dictionary = Some(field_name);
-        self
-    }
-}
-
-/// A data structure used to progressively construct the `Spec`.
-pub struct SpecBuilder {
-    /// All the interfaces entered so far.
-    interfaces_by_name: HashMap<NodeName, RefCell<InterfaceDeclaration>>,
-
-    /// All the enums entered so far.
-    string_enums_by_name: HashMap<NodeName, RefCell<StringEnum>>,
-
-    typedefs_by_name: HashMap<NodeName, RefCell<Type>>,
-
-    names: HashMap<String, Rc<String>>,
-}
-
-impl SpecBuilder {
-    pub fn new() -> Self {
-        SpecBuilder {
-            interfaces_by_name: HashMap::new(),
-            string_enums_by_name: HashMap::new(),
-            typedefs_by_name: HashMap::new(),
-            names: HashMap::new(),
-        }
-    }
-
-    pub fn names(&self) -> &HashMap<String, Rc<String>> {
-        &self.names
-    }
-
-    /// Return an `NodeName` for a name. Equality comparison
-    /// on `NodeName` can be performed by checking physical
-    /// equality.
-    pub fn node_name(&mut self, name: &str) -> NodeName {
-        if let Some(result) = self.names.get(name) {
-            return NodeName(result.clone());
-        }
-        let shared = Rc::new(name.to_string());
-        let result = NodeName(shared.clone());
-        self.names.insert(name.to_string(), shared);
-        result
-    }
-    pub fn get_node_name(&self, name: &str) -> Option<NodeName> {
-        self.names.get(name).map(|hit| NodeName(hit.clone()))
-    }
-    pub fn import_node_name(&mut self, node_name: &NodeName) {
-        self.names
-            .insert(node_name.to_string().clone(), node_name.0.clone());
-    }
-
-    pub fn field_name(&mut self, name: &str) -> FieldName {
-        if let Some(result) = self.names.get(name) {
-            return FieldName(result.clone());
-        }
-        let shared = Rc::new(name.to_string());
-        let result = FieldName(shared.clone());
-        self.names.insert(name.to_string(), shared);
-        result
-    }
-    pub fn import_field_name(&mut self, field_name: &FieldName) {
-        self.names
-            .insert(field_name.to_string().clone(), field_name.0.clone());
-    }
-
-    pub fn add_interface(&mut self, name: &NodeName) -> Option<RefMut<InterfaceDeclaration>> {
-        if self.interfaces_by_name.get(name).is_some() {
-            return None;
-        }
-        let result = RefCell::new(InterfaceDeclaration {
-            name: name.clone(),
-            contents: Obj::new(),
-            is_scope: false,
-            scoped_dictionary: None,
-        });
-        self.interfaces_by_name.insert(name.clone(), result);
-        self.interfaces_by_name.get(name).map(RefCell::borrow_mut)
-    }
-    pub fn get_interface(&mut self, name: &NodeName) -> Option<RefMut<InterfaceDeclaration>> {
-        self.interfaces_by_name.get(name).map(RefCell::borrow_mut)
-    }
-
-    /// Add a named enumeration.
-    pub fn add_string_enum(&mut self, name: &NodeName) -> Option<RefMut<StringEnum>> {
-        if self.string_enums_by_name.get(name).is_some() {
-            return None;
-        }
-        let e = RefCell::new(StringEnum {
-            name: name.clone(),
-            values: vec![],
-        });
-        self.string_enums_by_name.insert(name.clone(), e);
-        self.string_enums_by_name.get(name).map(RefCell::borrow_mut)
-    }
-
-    pub fn add_typedef(&mut self, name: &NodeName) -> Option<RefMut<Type>> {
-        if self.typedefs_by_name.get(name).is_some() {
-            return None;
-        }
-        let e = RefCell::new(TypeSpec::Void.required());
-        self.typedefs_by_name.insert(name.clone(), e);
-        self.typedefs_by_name.get(name).map(RefCell::borrow_mut)
-    }
-
-    /// Access an already added typedef.
-    pub fn get_typedef(&self, name: &NodeName) -> Option<Ref<Type>> {
-        self.typedefs_by_name.get(name).map(RefCell::borrow)
-    }
-
-    /// Access an already added typedef, mutably.
-    pub fn get_typedef_mut(&mut self, name: &NodeName) -> Option<RefMut<Type>> {
-        self.typedefs_by_name.get(name).map(RefCell::borrow_mut)
-    }
-
-    /// Generate the graph.
-    pub fn into_spec<'a>(self, options: SpecOptions<'a>) -> Spec {
-        // 1. Collect node names.
-        let mut interfaces_by_name = self.interfaces_by_name;
-        let interfaces_by_name: HashMap<_, _> = interfaces_by_name
-            .drain()
-            .map(|(k, v)| {
-                (
-                    k,
-                    Rc::new(Interface {
-                        declaration: RefCell::into_inner(v),
-                    }),
-                )
-            })
-            .collect();
-        let mut string_enums_by_name = self.string_enums_by_name;
-        let string_enums_by_name: HashMap<_, _> = string_enums_by_name
-            .drain()
-            .map(|(k, v)| (k, Rc::new(RefCell::into_inner(v))))
-            .collect();
-        let mut typedefs_by_name = self.typedefs_by_name;
-        let typedefs_by_name: HashMap<_, _> = typedefs_by_name
-            .drain()
-            .map(|(k, v)| (k, Rc::new(RefCell::into_inner(v))))
-            .collect();
-
-        let node_names: HashMap<_, _> = interfaces_by_name
-            .keys()
-            .chain(string_enums_by_name.keys())
-            .chain(typedefs_by_name.keys())
-            .map(|name| (name.to_string().clone(), name.clone()))
-            .collect();
-        debug!(target: "spec", "Established list of node names: {:?} ({})",
-            node_names.keys()
-                .sorted(),
-            node_names.len());
-
-        // 2. Collect all field names.
-        let mut fields = HashMap::new();
-        for interface in interfaces_by_name.values() {
-            for field in &interface.declaration.contents.fields {
-                fields.insert(field.name.to_string().clone(), field.name.clone());
-            }
-        }
-
-        let mut resolved_type_sums_by_name: HashMap<NodeName, HashSet<NodeName>> = HashMap::new();
-        {
-            // 3. Check that node names are used but not duplicated.
-            for name in node_names.values() {
-                let mut instances = 0;
-                if interfaces_by_name.contains_key(name) {
-                    instances += 1;
-                }
-                if string_enums_by_name.contains_key(name) {
-                    instances += 1;
-                }
-                if typedefs_by_name.contains_key(name) {
-                    instances += 1;
-                }
-                assert!(instances > 0, "Type name {} is never used", name.to_str());
-                assert_eq!(instances, 1, "Duplicate type name {}", name.to_str());
-            }
-
-            // 4. Check that all instances of `TypeSpec::NamedType` refer to an existing name.
-            let mut used_typenames = HashSet::new();
-            for type_ in typedefs_by_name.values() {
-                for name in type_.spec().typenames() {
-                    used_typenames.insert(name);
-                }
-            }
-            for interface in interfaces_by_name.values() {
-                for field in interface.declaration.contents.fields() {
-                    for name in field.type_().spec().typenames() {
-                        used_typenames.insert(name);
-                    }
-                }
-            }
-            for name in &used_typenames {
-                // Built-in types
-                if name.to_str() == "IdentifierName"
-                    || name.to_str() == "Identifier"
-                    || name.to_str() == "PropertyKey"
-                {
-                    continue;
-                }
-                if typedefs_by_name.contains_key(name) {
-                    continue;
-                }
-                if interfaces_by_name.contains_key(name) {
-                    continue;
-                }
-                if string_enums_by_name.contains_key(name) {
-                    continue;
-                }
-                panic!("No definition for type {}", name.to_str());
-            }
-
-            #[derive(Clone, Debug)]
-            enum TypeClassification {
-                SumOfInterfaces(HashSet<NodeName>),
-                Array,
-                Primitive,
-                StringEnum,
-                Optional,
-            }
-
-            // 5. Classify typedefs between
-            // - stuff that can only be put in a sum of interfaces (interfaces, sums of interfaces, typedefs thereof);
-            // - stuff that can never be put in a sum of interfaces (other stuff)
-            // - bad stuff that attempts to mix both
-
-            // name => unbound if we haven't seen the name yet
-            //      => `None` if we are currently classifying (used to detect cycles),
-            //      => `Some(SumOfInterfaces(set))` if the name describes a sum of interfaces
-            //      => `Some(BadForSumOfInterfaces)` if the name describes something that can't be summed with an interface
-            let mut classification: HashMap<NodeName, Option<TypeClassification>> = HashMap::new();
-            fn classify_type(
-                typedefs_by_name: &HashMap<NodeName, Rc<Type>>,
-                string_enums_by_name: &HashMap<NodeName, Rc<StringEnum>>,
-                interfaces_by_name: &HashMap<NodeName, Rc<Interface>>,
-                cache: &mut HashMap<NodeName, Option<TypeClassification>>,
-                type_: &TypeSpec,
-                name: &NodeName,
-            ) -> TypeClassification {
-                debug!(target: "spec", "classify_type for {:?}: walking {:?}", name, type_);
-                match *type_ {
-                    TypeSpec::Array { ref contents, .. } => {
-                        // Check that the contents are correct.
-                        let _ = classify_type(
-                            typedefs_by_name,
-                            string_enums_by_name,
-                            interfaces_by_name,
-                            cache,
-                            contents.spec(),
-                            name,
-                        );
-                        // Regardless, the result is bad for a sum of interfaces.
-                        debug!(target: "spec", "classify_type => don't put me in an interface");
-                        TypeClassification::Array
-                    }
-                    TypeSpec::Boolean
-                    | TypeSpec::Number
-                    | TypeSpec::String
-                    | TypeSpec::Void
-                    | TypeSpec::Offset
-                    | TypeSpec::UnsignedLong
-                    | TypeSpec::IdentifierName
-                    | TypeSpec::PropertyKey => {
-                        debug!(target: "spec", "classify_type => don't put me in an interface");
-                        TypeClassification::Primitive
-                    }
-                    TypeSpec::NamedType(ref name) => {
-                        if let Some(fetch) = cache.get(name) {
-                            if let Some(ref result) = *fetch {
-                                debug!(target: "spec", "classify_type {:?} => (cached) {:?}", name, result);
-                                return result.clone();
-                            } else {
-                                panic!("Cycle detected while examining {}", name.to_str());
-                            }
-                        }
-                        // Start lookup for this name.
-                        cache.insert(name.clone(), None);
-                        let result = if name.to_str() == "IdentifierName"
-                            || name.to_str() == "Identifier"
-                            || name.to_str() == "PropertyKey"
-                        {
-                            TypeClassification::Primitive
-                        } else if interfaces_by_name.contains_key(name) {
-                            let mut names = HashSet::new();
-                            names.insert(name.clone());
-                            TypeClassification::SumOfInterfaces(names)
-                        } else if string_enums_by_name.contains_key(name) {
-                            TypeClassification::StringEnum
-                        } else {
-                            let type_ = typedefs_by_name
-                                .get(name)
-                                .unwrap_or_else(|| panic!("Type {} not found", name)); // Completeness checked abover in this method.
-                            classify_type(
-                                typedefs_by_name,
-                                string_enums_by_name,
-                                interfaces_by_name,
-                                cache,
-                                type_.spec(),
-                                name,
-                            )
-                        };
-                        debug!(target: "spec", "classify_type {:?} => (inserting in cache) {:?}", name, result);
-                        cache.insert(name.clone(), Some(result.clone()));
-                        result
-                    }
-                    TypeSpec::TypeSum(ref sum) => {
-                        let mut names = HashSet::new();
-                        for type_ in sum.types() {
-                            match classify_type(typedefs_by_name, string_enums_by_name, interfaces_by_name, cache, type_, name) {
-                                TypeClassification::SumOfInterfaces(sum) => {
-                                    names.extend(sum);
-                                }
-                                class =>
-                                    panic!("In type {name}, there is a non-interface type {class:?} ({type_:?}) in a sum {sum:?}",
-                                        name = name.to_str(),
-                                        class = class,
-                                        sum = sum,
-                                        type_ = type_),
-                            }
-                        }
-                        debug!(target: "spec", "classify_type => built sum {:?}", names);
-                        TypeClassification::SumOfInterfaces(names)
-                    }
-                }
-            }
-            for (name, type_) in &typedefs_by_name {
-                classification.insert(name.clone(), None);
-                let class = classify_type(
-                    &typedefs_by_name,
-                    &string_enums_by_name,
-                    &interfaces_by_name,
-                    &mut classification,
-                    type_.spec(),
-                    name,
-                );
-                if !type_.is_optional() {
-                    classification.insert(name.clone(), Some(class));
-                } else {
-                    // FIXME: That looks weird.
-                    classification.insert(name.clone(), Some(TypeClassification::Optional));
-                }
-            }
-
-            // 6. Using this classification, check that the attributes of interfaces don't mix
-            // poorly items of both kinds.
-            for (name, interface) in &interfaces_by_name {
-                for field in interface.declaration.contents.fields() {
-                    classify_type(
-                        &typedefs_by_name,
-                        &string_enums_by_name,
-                        &interfaces_by_name,
-                        &mut classification,
-                        field.type_().spec(),
-                        name,
-                    );
-                }
-            }
-
-            // 7. Fill resolved_type_sums_by_name, for later use.
-            for (name, class) in classification.drain() {
-                if !typedefs_by_name.contains_key(&name) {
-                    continue;
-                }
-                if let Some(TypeClassification::SumOfInterfaces(sum)) = class {
-                    resolved_type_sums_by_name.insert(name, sum);
-                }
-            }
-        }
-
-        let spec = Spec {
-            interfaces_by_name,
-            string_enums_by_name,
-            typedefs_by_name,
-            resolved_type_sums_by_name,
-            node_names,
-            fields,
-            root: options.root.clone(),
-            null: options.null.clone(),
-        };
-
-        spec
-    }
-}
-
-/// Representation of an interface in a grammar declaration.
-///
-/// Interfaces represent nodes in the AST. Each interface
-/// has a name, a type, defines properties (also known as
-/// `attribute` in webidl) which hold values.
-#[derive(Debug)]
-pub struct Interface {
-    declaration: InterfaceDeclaration,
-}
-
-impl Interface {
-    /// Returns the full list of fields for this structure.
-    /// This method is in charge of:
-    /// - ensuring that the fields of parent structures are properly accounted for;
-    /// - disregarding ignored fields (i.e. `position`, `type`);
-    /// - disregarding fields with a single possible value.
-    pub fn contents(&self) -> &Obj {
-        &self.declaration.contents
-    }
-
-    /// Returns the name of the interface.
-    pub fn name(&self) -> &NodeName {
-        &self.declaration.name
-    }
-
-    /// Returns a type specification for this interface.
-    ///
-    /// The result is a `NamedType` with this interface's name.
-    pub fn spec(&self) -> TypeSpec {
-        TypeSpec::NamedType(self.name().clone())
-    }
-
-    pub fn type_(&self) -> Type {
-        self.spec().required()
-    }
-
-    pub fn get_field_by_name(&self, name: &FieldName) -> Option<&Field> {
-        for field in self.contents().fields() {
-            if name == field.name() {
-                return Some(field);
-            }
-        }
-        None
-    }
-
-    pub fn is_scope(&self) -> bool {
-        self.declaration.is_scope
-    }
-
-    /// If this interface introduces a scoped dictionary change,
-    /// return Some(field_name) where field_name is
-    /// the field of this interface containing the name of
-    /// the dictionary to use in the sub-ast.
-    pub fn scoped_dictionary(&self) -> Option<FieldName> {
-        self.declaration.scoped_dictionary.clone()
-    }
-}
-
-/// Immutable representation of the spec.
-pub struct Spec {
-    interfaces_by_name: HashMap<NodeName, Rc<Interface>>,
-    string_enums_by_name: HashMap<NodeName, Rc<StringEnum>>,
-    typedefs_by_name: HashMap<NodeName, Rc<Type>>,
-
-    resolved_type_sums_by_name: HashMap<NodeName, HashSet<NodeName>>,
-
-    node_names: HashMap<String, NodeName>,
-    fields: HashMap<String, FieldName>,
-    root: NodeName,
-    null: NodeName,
-}
-
-impl Spec {
-    pub fn get_interface_by_name(&self, name: &NodeName) -> Option<&Interface> {
-        self.interfaces_by_name
-            .get(name)
-            .map(std::borrow::Borrow::borrow)
-    }
-    pub fn interfaces_by_name(&self) -> &HashMap<NodeName, Rc<Interface>> {
-        &self.interfaces_by_name
-    }
-    pub fn string_enums_by_name(&self) -> &HashMap<NodeName, Rc<StringEnum>> {
-        &self.string_enums_by_name
-    }
-    pub fn typedefs_by_name(&self) -> &HashMap<NodeName, Rc<Type>> {
-        &self.typedefs_by_name
-    }
-    pub fn resolved_sums_of_interfaces_by_name(&self) -> &HashMap<NodeName, HashSet<NodeName>> {
-        &self.resolved_type_sums_by_name
-    }
-
-    pub fn get_type_by_name(&self, name: &NodeName) -> Option<NamedType> {
-        if let Some(interface) = self.interfaces_by_name.get(name) {
-            return Some(NamedType::Interface(interface.clone()));
-        }
-        if let Some(strings_enum) = self.string_enums_by_name.get(name) {
-            return Some(NamedType::StringEnum(strings_enum.clone()));
-        }
-        if let Some(type_) = self.typedefs_by_name.get(name) {
-            return Some(NamedType::Typedef(type_.clone()));
-        }
-        None
-    }
-    pub fn get_field_name(&self, name: &str) -> Option<&FieldName> {
-        self.fields.get(name)
-    }
-    pub fn get_node_name(&self, name: &str) -> Option<&NodeName> {
-        self.node_names.get(name)
-    }
-    pub fn node_names(&self) -> &HashMap<String, NodeName> {
-        &self.node_names
-    }
-    pub fn field_names(&self) -> &HashMap<String, FieldName> {
-        &self.fields
-    }
-    pub fn get_root_name(&self) -> &NodeName {
-        &self.root
-    }
-    pub fn get_null_name(&self) -> &NodeName {
-        &self.null
-    }
-
-    /// The starting point for parsing.
-    pub fn get_root(&self) -> NamedType {
-        self.get_type_by_name(&self.root).unwrap()
-    }
-}
-
-/// Informations passed during the creation of a `Spec` object.
-pub struct SpecOptions<'a> {
-    /// The name of the node used to start encoding.
-    pub root: &'a NodeName,
-    pub null: &'a NodeName,
-}
-
-pub trait HasInterfaces {
-    fn get_interface(&self, spec: &Spec, name: &NodeName) -> Option<Rc<Interface>>;
-}
-
-impl HasInterfaces for NamedType {
-    fn get_interface(&self, spec: &Spec, name: &NodeName) -> Option<Rc<Interface>> {
-        debug!(target: "spec", "get_interface, looking for {:?} in named type {:?}", name, self);
-        match *self {
-            NamedType::Interface(_) => None,
-            NamedType::StringEnum(_) => None,
-            NamedType::Typedef(ref type_) => type_.spec().get_interface(spec, name),
-        }
-    }
-}
-
-impl HasInterfaces for TypeSpec {
-    fn get_interface(&self, spec: &Spec, name: &NodeName) -> Option<Rc<Interface>> {
-        debug!(target: "spec", "get_interface, looking for {:?} in spec {:?}", name, self);
-        match *self {
-            TypeSpec::NamedType(ref my_name) => {
-                let follow = spec.get_type_by_name(my_name);
-                if let Some(follow) = follow {
-                    if name == my_name {
-                        follow.as_interface(spec)
-                    } else {
-                        follow.get_interface(spec, name)
-                    }
-                } else {
-                    None
-                }
-            }
-            TypeSpec::TypeSum(ref sum) => sum.get_interface(spec, name),
-            _ => None,
-        }
-    }
-}
diff --git a/third_party/rust/binjs_meta/src/util.rs b/third_party/rust/binjs_meta/src/util.rs
deleted file mode 100644
index d5fb75de36..0000000000
--- a/third_party/rust/binjs_meta/src/util.rs
+++ /dev/null
@@ -1,535 +0,0 @@
-//! Miscellaneous utilities.
-
-pub trait ToStr {
-    /// Return the value as a `str`.
-    fn to_str(&self) -> &str;
-    fn newline(&self) -> String {
-        format!("{}\n", self.to_str())
-    }
-
-    /// Append newline if the string is not empty.
-    fn newline_if_not_empty(&self) -> String {
-        let s = self.to_str();
-        if s.len() == 0 {
-            "".to_string()
-        } else {
-            format!("{}\n", s)
-        }
-    }
-}
-
-impl<'a> ToStr for &'a str {
-    fn to_str(&self) -> &str {
-        *self
-    }
-}
-
-impl ToStr for str {
-    fn to_str(&self) -> &str {
-        self
-    }
-}
-
-impl ToStr for String {
-    fn to_str(&self) -> &str {
-        &self
-    }
-}
-
-/// A string or string-like construction that can be
-/// converted to upper case, lower case, class case, etc
-pub trait ToCases: ToStr {
-    /// Return the value in class case, e.g.
-    ///
-    /// ```
-    /// use binjs_meta::util::ToCases;
-    ///
-    /// assert_eq!(&"foo_bar".to_class_cases(), "FooBar");
-    /// assert_eq!(&"fooBars".to_class_cases(), "FooBars");
-    /// ```
-    fn to_class_cases(&self) -> String {
-        self.to_str().to_class_cases()
-    }
-
-    /// Return the value in a format suitable for use as a cpp `enum`
-    /// variants.
-    ///
-    /// ```
-    /// use binjs_meta::util::ToCases;
-    ///
-    /// assert_eq!(&"foo_bar".to_cpp_enum_case(), "FooBar");
-    /// assert_eq!(&"fooBars".to_cpp_enum_case(), "FooBars");
-    /// assert_eq!(&"+=".to_cpp_enum_case(), "PlusAssign");
-    /// ```
-    fn to_cpp_enum_case(&self) -> String {
-        self.to_str().to_cpp_enum_case()
-    }
-
-    /// Return the value in a format suitable for use as a C++ field name
-    /// or identifier.
-    ///
-    /// ```
-    /// use binjs_meta::util::ToCases;
-    ///
-    /// assert_eq!(&"foo_bar".to_cpp_field_case(), "fooBar");
-    /// assert_eq!(&"fooBars".to_cpp_field_case(), "fooBars");
-    /// assert_eq!(&"class".to_cpp_field_case(), "class_");
-    /// ```
-    fn to_cpp_field_case(&self) -> String {
-        self.to_str().to_cpp_field_case()
-    }
-
-    /// Return the value in a format suitable for use as a Rust field name
-    /// or identifier.
-    ///
-    /// ```
-    /// use binjs_meta::util::ToCases;
-    ///
-    /// assert_eq!(&"foo_bar".to_rust_identifier_case(), "foo_bar");
-    /// assert_eq!(&"fooBars".to_rust_identifier_case(), "foo_bars");
-    /// assert_eq!(&"self".to_rust_identifier_case(), "self_");
-    /// ```
-    fn to_rust_identifier_case(&self) -> String {
-        self.to_str().to_rust_identifier_case()
-    }
-}
-
-impl<T> ToCases for T
-where
-    T: ToStr,
-{
-    fn to_class_cases(&self) -> String {
-        match self.to_str() {
-            "" => "Null".to_string(),
-            other => {
-                let result = inflector::cases::pascalcase::to_pascal_case(other);
-                assert!(
-                    result.to_str().len() != 0,
-                    "Could not convert '{}' to class case",
-                    other
-                );
-                result
-            }
-        }
-    }
-    fn to_cpp_enum_case(&self) -> String {
-        match self.to_str() {
-            "+=" => "PlusAssign".to_string(),
-            "-=" => "MinusAssign".to_string(),
-            "*=" => "MulAssign".to_string(),
-            "/=" => "DivAssign".to_string(),
-            "%=" => "ModAssign".to_string(),
-            "**=" => "PowAssign".to_string(),
-            "<<=" => "LshAssign".to_string(),
-            ">>=" => "RshAssign".to_string(),
-            ">>>=" => "UrshAssign".to_string(),
-            "|=" => "BitOrAssign".to_string(),
-            "^=" => "BitXorAssign".to_string(),
-            "&=" => "BitAndAssign".to_string(),
-            "," => "Comma".to_string(),
-            "||" => "LogicalOr".to_string(),
-            "&&" => "LogicalAnd".to_string(),
-            "|" => "BitOr".to_string(),
-            "^" => "BitXor".to_string(),
-            "&" => "BitAnd".to_string(),
-            "==" => "Eq".to_string(),
-            "!=" => "Neq".to_string(),
-            "===" => "StrictEq".to_string(),
-            "!==" => "StrictNeq".to_string(),
-            "<" => "LessThan".to_string(),
-            "<=" => "LeqThan".to_string(),
-            ">" => "GreaterThan".to_string(),
-            ">=" => "GeqThan".to_string(),
-            "<<" => "Lsh".to_string(),
-            ">>" => "Rsh".to_string(),
-            ">>>" => "Ursh".to_string(),
-            "+" => "Plus".to_string(),
-            "-" => "Minus".to_string(),
-            "~" => "BitNot".to_string(),
-            "*" => "Mul".to_string(),
-            "/" => "Div".to_string(),
-            "%" => "Mod".to_string(),
-            "**" => "Pow".to_string(),
-            "!" => "Not".to_string(),
-            "++" => "Incr".to_string(),
-            "--" => "Decr".to_string(),
-            "" => "_Null".to_string(),
-            _ => {
-                let class_cased = self.to_class_cases();
-                assert!(
-                    &class_cased != "",
-                    "FIXME: `to_class_cases` does not handle {} yet",
-                    self.to_str()
-                );
-                class_cased
-            }
-        }
-    }
-    fn to_cpp_field_case(&self) -> String {
-        let snake = inflector::cases::camelcase::to_camel_case(self.to_str());
-        match &snake as &str {
-            "class" => "class_".to_string(),
-            "operator" => "operator_".to_string(),
-            "const" => "const_".to_string(),
-            "void" => "void_".to_string(),
-            "delete" => "delete_".to_string(),
-            "in" => "in_".to_string(),
-            // Names reserved by us
-            "result" => "result_".to_string(),
-            "kind" => "kind_".to_string(),
-            // Special cases
-            "" => unimplemented!(
-                "FIXME: `to_cpp_field_case` does not handle {} yet",
-                self.to_str()
-            ),
-            _ => snake,
-        }
-    }
-    fn to_rust_identifier_case(&self) -> String {
-        let snake = inflector::cases::snakecase::to_snake_case(self.to_str());
-        match &snake as &str {
-            "self" => "self_".to_string(),
-            "super" => "super_".to_string(),
-            "type" => "type_".to_string(),
-            "" if self.to_str() == "" => "null".to_string(),
-            "" => unimplemented!(
-                "FIXME: `to_rust_identifier_case` does not handle {} yet",
-                self.to_str()
-            ),
-            _ => snake,
-        }
-    }
-}
-
-/// A string or string-like construction that can be reindented.
-pub trait Reindentable {
-    /// Remove leading whitespace, replace it with `prefix`.
-    ///
-    /// If `self` spans more than one line, the leading whitespace
-    /// is computed from the first line and extracted from all lines
-    /// and `prefix` is added to all lines.
-    ///
-    /// ```
-    /// use binjs_meta::util::Reindentable;
-    ///
-    /// assert_eq!(&"abc".reindent("   "), "   abc");
-    /// assert_eq!(&" def".reindent("   "), "   def");
-    /// assert_eq!(&"  ghi".reindent("   "), "   ghi");
-    /// assert_eq!(&" jkl\n    mno".reindent("   "), "   jkl\n      mno");
-    /// ```
-    fn reindent(&self, prefix: &str) -> String;
-
-    /// Remove leading whitespace, replace it with `prefix`,
-    /// ensure that the text fits within `width` columns.
-    ///
-    /// If `self` spans more than one line, the leading whitespace
-    /// is computed from the first line and extracted from all lines.
-    /// and `prefix` is added to all lines.
-    ///
-    /// If the result goes past `width` columns, `self` is split
-    /// into several lines to try and fit within `width` columns.
-    ///
-    /// ```
-    /// use binjs_meta::util::Reindentable;
-    ///
-    /// assert_eq!(&"abc".fit("// ", 30), "// abc");
-    /// assert_eq!(&" def".fit("// ", 30), "// def");
-    /// assert_eq!(&"  ghi".fit("// ", 30), "// ghi");
-    /// assert_eq!(&" jkl\n    mno".fit("// ", 30), "// jkl\n//    mno");
-    /// assert_eq!(&"abc def ghi".fit("// ", 8), "// abc\n// def\n// ghi");
-    /// assert_eq!(&"abc def ghi".fit("// ", 5), "// abc\n// def\n// ghi");
-    /// ```
-    fn fit(&self, prefix: &str, width: usize) -> String;
-}
-
-impl<T> Reindentable for T
-where
-    T: ToStr,
-{
-    fn reindent(&self, prefix: &str) -> String {
-        use itertools::Itertools;
-
-        let str = self.to_str();
-
-        // Determine the number of whitespace chars on the first line.
-        // Trim that many whitespace chars on the following lines.
-        if let Some(first_line) = str.lines().next() {
-            let indent_len = first_line
-                .chars()
-                .take_while(|c| char::is_whitespace(*c))
-                .count();
-            format!(
-                "{}",
-                str.lines()
-                    .map(|line| if line.len() > indent_len {
-                        format!(
-                            "{prefix}{text}",
-                            prefix = prefix,
-                            text = line[indent_len..].to_string()
-                        )
-                    } else {
-                        "".to_string()
-                    })
-                    .format("\n")
-            )
-        } else {
-            "".to_string()
-        }
-    }
-
-    fn fit(&self, prefix: &str, columns: usize) -> String {
-        use itertools::Itertools;
-
-        let str = self.to_str();
-        // Determine the number of whitespace chars on the first line.
-        // Trim that many whitespace chars on the following lines.
-        if let Some(first_line) = str.lines().next() {
-            let indent_len = first_line
-                .chars()
-                .take_while(|c| char::is_whitespace(*c))
-                .count();
-            let mut lines = vec![];
-            'per_line: for line in str.lines() {
-                eprintln!("Inspecting line {}", line);
-                let text = &line[indent_len..];
-                let mut gobbled = 0;
-                while text.len() > gobbled {
-                    let rest = &text[gobbled..];
-                    eprintln!("Line still contains {} ({})", rest, gobbled);
-                    if rest.len() + prefix.len() > columns {
-                        // Try and find the largest prefix of `text` that fits within `columns`.
-                        let mut iterator = rest
-                            .chars()
-                            .enumerate()
-                            .filter(|&(_, c)| char::is_whitespace(c));
-                        let mut last_whitespace_before_break = None;
-                        let mut first_whitespace_after_break = None;
-                        while let Some((found_pos, _)) = iterator.next() {
-                            if found_pos + prefix.len() <= columns {
-                                last_whitespace_before_break = Some(found_pos);
-                            } else {
-                                first_whitespace_after_break = Some(found_pos);
-                                break;
-                            }
-                        }
-
-                        match (last_whitespace_before_break, first_whitespace_after_break) {
-                            (None, None) => {
-                                eprintln!("Ok, string didn't contain any whitespace: '{}'", rest);
-                                // Oh, `rest` does not contain any whitespace. Well, use everything.
-                                lines.push(format!("{prefix}{rest}", prefix = prefix, rest = rest));
-                                continue 'per_line;
-                            }
-                            (Some(pos), _) | (None, Some(pos)) if pos != 0 => {
-                                eprintln!("Best whitespace found at {}", pos);
-                                // Use `rest[0..pos]`, trimmed right.
-                                gobbled += pos + 1;
-                                let line = format!(
-                                    "{prefix}{rest}",
-                                    prefix = prefix,
-                                    rest = rest[0..pos].trim_end()
-                                );
-                                lines.push(line)
-                            }
-                            _else => panic!("{:?}", _else),
-                        }
-                    } else {
-                        let line = format!("{prefix}{rest}", prefix = prefix, rest = rest);
-                        lines.push(line);
-                        continue 'per_line;
-                    }
-                }
-            }
-            format!("{lines}", lines = lines.iter().format("\n"))
-        } else {
-            "".to_string()
-        }
-    }
-}
-
-impl Reindentable for Option<String> {
-    fn reindent(&self, prefix: &str) -> String {
-        match *self {
-            None => "".to_string(),
-            Some(ref string) => string.reindent(prefix),
-        }
-    }
-    fn fit(&self, prefix: &str, columns: usize) -> String {
-        match *self {
-            None => "".to_string(),
-            Some(ref string) => string.fit(prefix, columns),
-        }
-    }
-}
-
-pub mod name_sorter {
-    use std;
-    use std::collections::HashMap;
-
-    /// A type used to sort names by length, then prefixes, to speed
-    /// up lookups.
-    pub struct NameSorter<T> {
-        per_length: HashMap<usize, Node<T>>,
-        len: usize,
-    }
-    impl<T> NameSorter<T> {
-        pub fn new() -> Self {
-            NameSorter {
-                per_length: HashMap::new(),
-                len: 0,
-            }
-        }
-
-        /// Return the number of items in the sorter.
-        pub fn len(&self) -> usize {
-            debug_assert!({
-                // Let's check that the length is always the sum of sublengths.
-                let len = self
-                    .per_length
-                    .values()
-                    .map(|v| match v {
-                        &Node::Leaf(Some(_)) => 1,
-                        &Node::Leaf(_) => panic!("Invariant error: empty leaf!"),
-                        &Node::Internal { ref len, .. } => *len,
-                    })
-                    .fold(0, |x, y| (x + y));
-                len == self.len
-            });
-            self.len
-        }
-
-        /// Insert a value in a sorter.
-        ///
-        /// ```
-        /// let mut sorter = binjs_meta::util::name_sorter::NameSorter::new();
-        /// assert_eq!(sorter.len(), 0);
-        ///
-        /// assert!(sorter.insert("abcd", 0).is_none());
-        /// assert_eq!(sorter.len(), 1);
-        /// assert_eq!(*sorter.get("abcd").unwrap(), 0);
-        /// assert!(sorter.get("dbca").is_none());
-        /// assert!(sorter.get("").is_none());
-        ///
-        /// assert!(sorter.insert("dcba", 1).is_none());
-        /// assert_eq!(sorter.len(), 2);
-        /// assert_eq!(*sorter.get("abcd").unwrap(), 0);
-        /// assert_eq!(*sorter.get("dcba").unwrap(), 1);
-        /// assert!(sorter.get("").is_none());
-        ///
-        /// assert_eq!(sorter.insert("abcd", 3).unwrap(), 0);
-        /// assert_eq!(sorter.len(), 2);
-        /// assert_eq!(*sorter.get("abcd").unwrap(), 3);
-        /// assert_eq!(*sorter.get("dcba").unwrap(), 1);
-        /// assert!(sorter.get("").is_none());
-        ///
-        /// assert!(sorter.insert("", 4).is_none());
-        /// assert_eq!(sorter.len(), 3);
-        /// assert_eq!(*sorter.get("abcd").unwrap(), 3);
-        /// assert_eq!(*sorter.get("dcba").unwrap(), 1);
-        /// assert_eq!(*sorter.get("").unwrap(), 4);
-        ///
-        /// assert_eq!(sorter.insert("", 5).unwrap(), 4);
-        /// assert_eq!(sorter.len(), 3);
-        /// assert_eq!(*sorter.get("abcd").unwrap(), 3);
-        /// assert_eq!(*sorter.get("dcba").unwrap(), 1);
-        /// assert_eq!(*sorter.get("").unwrap(), 5);
-        /// ```
-        pub fn insert(&mut self, key: &str, value: T) -> Option<T> {
-            if let Some(node) = self.per_length.get_mut(&key.len()) {
-                let result = node.insert(key, value);
-                if result.is_none() {
-                    self.len += 1;
-                }
-                return result;
-            }
-            let node = Node::new(key, value);
-            self.per_length.insert(key.len(), node);
-            self.len += 1;
-            None
-        }
-
-        pub fn iter(&self) -> impl Iterator<Item = (usize, &Node<T>)> {
-            self.per_length.iter().map(|(&len, node)| (len, node))
-        }
-
-        pub fn get(&self, key: &str) -> Option<&T> {
-            self.per_length
-                .get(&key.len())
-                .and_then(|node| node.get(key))
-        }
-    }
-
-    pub enum Node<T> {
-        Leaf(Option<T>),
-        Internal {
-            /// The children of this node.
-            ///
-            /// Invariant: May only be empty during a call to `insert()`.
-            children: HashMap<char, Node<T>>,
-
-            /// Number of leaves in this subtree.
-            len: usize,
-        },
-    }
-    impl<T> Node<T> {
-        fn get(&self, key: &str) -> Option<&T> {
-            match (self, key.chars().next()) {
-                (&Node::Leaf(Some(ref result)), None) => Some(result),
-                (&Node::Internal { ref children, .. }, Some(c)) => {
-                    debug_assert!(children.len() != 0);
-                    children.get(&c).and_then(|node| node.get(&key[1..]))
-                }
-                _ => panic!("Invariant error: length"),
-            }
-        }
-
-        fn insert(&mut self, key: &str, value: T) -> Option<T> {
-            match (self, key.chars().next()) {
-                (&mut Node::Leaf(ref mut old), None) => {
-                    // We have reached the end of `name`.
-                    let mut data = Some(value);
-                    std::mem::swap(&mut data, old);
-                    data
-                }
-                (
-                    &mut Node::Internal {
-                        ref mut children,
-                        ref mut len,
-                    },
-                    Some(c),
-                ) => {
-                    let result = {
-                        let entry = if key.len() == 1 {
-                            children.entry(c).or_insert_with(|| Node::Leaf(None))
-                        } else {
-                            children.entry(c).or_insert_with(|| Node::Internal {
-                                children: HashMap::new(),
-                                len: 0,
-                            })
-                        };
-                        entry.insert(&key[1..], value)
-                    };
-                    if result.is_none() {
-                        *len += 1;
-                    }
-                    debug_assert!(*len > 0);
-                    debug_assert!(children.len() != 0);
-                    result
-                }
-                _ => panic!("Invariant error: length"),
-            }
-        }
-        fn new(key: &str, value: T) -> Self {
-            if key.len() == 0 {
-                Node::Leaf(Some(value))
-            } else {
-                let mut node = Node::Internal {
-                    children: HashMap::new(),
-                    len: 0,
-                };
-                assert!(node.insert(key, value).is_none());
-                node
-            }
-        }
-    }
-}
diff --git a/third_party/rust/cssparser/.cargo-checksum.json b/third_party/rust/cssparser/.cargo-checksum.json
index 02cb25a379..b6625714f2 100644
--- a/third_party/rust/cssparser/.cargo-checksum.json
+++ b/third_party/rust/cssparser/.cargo-checksum.json
@@ -1 +1 @@
-{"files":{"Cargo.toml":"53761c6ce14b954599553cc780908f422dc9e48b6183876a7be0e435fd200fa0","LICENSE":"fab3dd6bdab226f1c08630b1dd917e11fcb4ec5e1e020e2c16f83a0a13863e85","README.md":"a533b45a9c43083c6a6000a9c99a1acfed123d6430b232352ae02f1144a09f12","build.rs":"a9619dbf086f20d3cbfee2b05c1a761f683acb30191d7286d24ad53617e9043b","build/match_byte.rs":"f57faf0597cb7b3e32999c5fb1215a43a5603121588c67d5031f720362171e1c","docs/404.html":"025861f76f8d1f6d67c20ab624c6e418f4f824385e2dd8ad8732c4ea563c6a2e","docs/index.html":"025861f76f8d1f6d67c20ab624c6e418f4f824385e2dd8ad8732c4ea563c6a2e","src/color.rs":"d2e14b341fbc2d141b1fed4b4a91b31e32bf92461b067036bd4227cda19e4e72","src/cow_rc_str.rs":"89b5dff5cf80eef3fcff0c11799e54a978d02d8b8963a621fbb999d35e7c03a3","src/from_bytes.rs":"b1cf15c4e975523fef46b575598737a39f3c63e5ce0b2bfd6ec627c69c6ea54a","src/lib.rs":"2b20764b713020d59b7533ee686ef688ad70e85f61d2b3fab70e1af0f409f8e4","src/macros.rs":"cc5b13b5c605cd138b8311a9484d184fa3d063189e75d291223178f9eafe53c7","src/nth.rs":"2490db52a28d09009d73474336f12738ef5f0ffbbc4f1b49ee1e56ca9ca8b34b","src/parser.rs":"3bfeeda068567699e6ff5a6967c95473bc99910aedceb406347e05a98339cdac","src/rules_and_declarations.rs":"19d0079eca3e1776823ef8a16a0afd1619b9f7a392068c583487d891674225b2","src/serializer.rs":"c3b810e0970688a40d279101c379cfee110b100e1ff1a2cc40363971fd7bf591","src/size_of_tests.rs":"acd10556e060e4149e9f565f36058ca26bf3b3296d512d45127845fa12b94539","src/tests.rs":"247b0b332e77c1703ffbaaad9b5540571609e0fdc49f91998171820619d06f03","src/tokenizer.rs":"76360e46c0efceff82b6336b3522c95bdb8ef96379a617e7eed12eec9bad7ab7","src/unicode_range.rs":"20d96f06fbb73921e308cc340c9fe065e27f19843005689fb259007a6a372bcc"},"package":"754b69d351cdc2d8ee09ae203db831e005560fc6030da058f86ad60c92a9cb0a"}
\ No newline at end of file
+{"files":{"Cargo.toml":"3433246693b26ae30214281dadded990707a23c70bc915ee2ca5b1482f15b05c","LICENSE":"fab3dd6bdab226f1c08630b1dd917e11fcb4ec5e1e020e2c16f83a0a13863e85","README.md":"a533b45a9c43083c6a6000a9c99a1acfed123d6430b232352ae02f1144a09f12","build.rs":"a9619dbf086f20d3cbfee2b05c1a761f683acb30191d7286d24ad53617e9043b","build/match_byte.rs":"f57faf0597cb7b3e32999c5fb1215a43a5603121588c67d5031f720362171e1c","docs/404.html":"025861f76f8d1f6d67c20ab624c6e418f4f824385e2dd8ad8732c4ea563c6a2e","docs/index.html":"025861f76f8d1f6d67c20ab624c6e418f4f824385e2dd8ad8732c4ea563c6a2e","src/color.rs":"d8f574e2b6b3f5c144e5030037eb5e9db31d96d484a60e6503ca98395fd7f3af","src/cow_rc_str.rs":"89b5dff5cf80eef3fcff0c11799e54a978d02d8b8963a621fbb999d35e7c03a3","src/from_bytes.rs":"b1cf15c4e975523fef46b575598737a39f3c63e5ce0b2bfd6ec627c69c6ea54a","src/lib.rs":"2b20764b713020d59b7533ee686ef688ad70e85f61d2b3fab70e1af0f409f8e4","src/macros.rs":"cc5b13b5c605cd138b8311a9484d184fa3d063189e75d291223178f9eafe53c7","src/nth.rs":"ae2f8b0f2c9e8b1ffb3cb842ca78c0060829a7d2e0762d1eb427f40188686ba1","src/parser.rs":"5c8ed6ccc069d0d2526016aeeba7200275b5fb1d8271926ccdb7a848124cde45","src/rules_and_declarations.rs":"1f171431f5f4d0d6bd631deeb7c684100c6e15f10e06b8fff1e6d676567c27c3","src/serializer.rs":"c3b810e0970688a40d279101c379cfee110b100e1ff1a2cc40363971fd7bf591","src/size_of_tests.rs":"acd10556e060e4149e9f565f36058ca26bf3b3296d512d45127845fa12b94539","src/tests.rs":"8022811a7fc90199e1f775fb1cf567ac15fca8a00d5f2cf934863a8b36997cba","src/tokenizer.rs":"76360e46c0efceff82b6336b3522c95bdb8ef96379a617e7eed12eec9bad7ab7","src/unicode_range.rs":"20d96f06fbb73921e308cc340c9fe065e27f19843005689fb259007a6a372bcc"},"package":"809d22aba9ffd53e9028f2d37261f1826ef613d0e96b1a5ddeefa97cde82bcca"}
\ No newline at end of file
diff --git a/third_party/rust/cssparser/Cargo.toml b/third_party/rust/cssparser/Cargo.toml
index 16c3892362..17fe9b59bf 100644
--- a/third_party/rust/cssparser/Cargo.toml
+++ b/third_party/rust/cssparser/Cargo.toml
@@ -13,7 +13,7 @@
 [package]
 edition = "2018"
 name = "cssparser"
-version = "0.27.2"
+version = "0.28.0"
 authors = ["Simon Sapin <simon.sapin@exyr.org>"]
 build = "build.rs"
 exclude = ["src/css-parsing-tests/**", "src/big-data-url.css"]
diff --git a/third_party/rust/cssparser/src/color.rs b/third_party/rust/cssparser/src/color.rs
index a7d72057be..8d0d521f3b 100644
--- a/third_party/rust/cssparser/src/color.rs
+++ b/third_party/rust/cssparser/src/color.rs
@@ -291,7 +291,7 @@ impl Color {
                 let name = name.clone();
                 return input.parse_nested_block(|arguments| {
                     parse_color_function(component_parser, &*name, arguments)
-                })
+                });
             }
             _ => Err(()),
         }
diff --git a/third_party/rust/cssparser/src/nth.rs b/third_party/rust/cssparser/src/nth.rs
index 063875f7ca..a0c0a0070c 100644
--- a/third_party/rust/cssparser/src/nth.rs
+++ b/third_party/rust/cssparser/src/nth.rs
@@ -73,12 +73,12 @@ pub fn parse_nth<'i, 't>(input: &mut Parser<'i, 't>) -> Result<(i32, i32), Basic
             ref token => {
                 let token = token.clone();
                 Err(input.new_basic_unexpected_token_error(token))
-            },
+            }
         },
         ref token => {
             let token = token.clone();
             Err(input.new_basic_unexpected_token_error(token))
-        },
+        }
     }
 }
 
diff --git a/third_party/rust/cssparser/src/parser.rs b/third_party/rust/cssparser/src/parser.rs
index 21beb6b28d..8b2a231b2f 100644
--- a/third_party/rust/cssparser/src/parser.rs
+++ b/third_party/rust/cssparser/src/parser.rs
@@ -933,17 +933,15 @@ impl<'i: 't, 't> Parser<'i, 't> {
                 Ok(&Token::Function(_))
                 | Ok(&Token::ParenthesisBlock)
                 | Ok(&Token::SquareBracketBlock)
-                | Ok(&Token::CurlyBracketBlock) => {
-                    self.parse_nested_block(|input| {
-                        input.expect_no_error_token().map_err(Into::into)
-                    }).map_err(ParseError::<()>::basic)?
-                }
+                | Ok(&Token::CurlyBracketBlock) => self
+                    .parse_nested_block(|input| input.expect_no_error_token().map_err(Into::into))
+                    .map_err(ParseError::<()>::basic)?,
                 Ok(t) => {
                     // FIXME: maybe these should be separate variants of
                     // BasicParseError instead?
                     if t.is_parse_error() {
                         let token = t.clone();
-                        return Err(self.new_basic_unexpected_token_error(token))
+                        return Err(self.new_basic_unexpected_token_error(token));
                     }
                 }
                 Err(_) => return Ok(()),
diff --git a/third_party/rust/cssparser/src/rules_and_declarations.rs b/third_party/rust/cssparser/src/rules_and_declarations.rs
index 6034452f17..5d334a6f29 100644
--- a/third_party/rust/cssparser/src/rules_and_declarations.rs
+++ b/third_party/rust/cssparser/src/rules_and_declarations.rs
@@ -5,7 +5,7 @@
 // https://drafts.csswg.org/css-syntax/#parsing
 
 use super::{BasicParseError, BasicParseErrorKind, Delimiter};
-use super::{ParseError, Parser, SourceLocation, Token};
+use super::{ParseError, Parser, Token};
 use crate::cow_rc_str::CowRcStr;
 use crate::parser::{parse_nested_block, parse_until_after, parse_until_before, ParserState};
 
@@ -130,10 +130,10 @@ pub trait AtRuleParser<'i> {
     fn rule_without_block(
         &mut self,
         prelude: Self::PreludeNoBlock,
-        location: SourceLocation,
+        start: &ParserState,
     ) -> Self::AtRule {
         let _ = prelude;
-        let _ = location;
+        let _ = start;
         panic!(
             "The `AtRuleParser::rule_without_block` method must be overriden \
              if `AtRuleParser::parse_prelude` ever returns `AtRuleType::WithoutBlock`."
@@ -153,11 +153,11 @@ pub trait AtRuleParser<'i> {
     fn parse_block<'t>(
         &mut self,
         prelude: Self::PreludeBlock,
-        location: SourceLocation,
+        start: &ParserState,
         input: &mut Parser<'i, 't>,
     ) -> Result<Self::AtRule, ParseError<'i, Self::Error>> {
         let _ = prelude;
-        let _ = location;
+        let _ = start;
         let _ = input;
         Err(input.new_error(BasicParseErrorKind::AtRuleBodyInvalid))
     }
@@ -210,11 +210,11 @@ pub trait QualifiedRuleParser<'i> {
     fn parse_block<'t>(
         &mut self,
         prelude: Self::Prelude,
-        location: SourceLocation,
+        start: &ParserState,
         input: &mut Parser<'i, 't>,
     ) -> Result<Self::QualifiedRule, ParseError<'i, Self::Error>> {
         let _ = prelude;
-        let _ = location;
+        let _ = start;
         let _ = input;
         Err(input.new_error(BasicParseErrorKind::QualifiedRuleInvalid))
     }
@@ -267,7 +267,9 @@ where
         loop {
             let start = self.input.state();
             match self.input.next_including_whitespace_and_comments() {
-                Ok(&Token::WhiteSpace(_)) | Ok(&Token::Comment(_)) | Ok(&Token::Semicolon) => continue,
+                Ok(&Token::WhiteSpace(_)) | Ok(&Token::Comment(_)) | Ok(&Token::Semicolon) => {
+                    continue
+                }
                 Ok(&Token::Ident(ref name)) => {
                     let name = name.clone();
                     let result = {
@@ -288,9 +290,7 @@ where
                 Ok(token) => {
                     let token = token.clone();
                     let result = self.input.parse_until_after(Delimiter::Semicolon, |_| {
-                        Err(start
-                            .source_location()
-                            .new_unexpected_token_error(token))
+                        Err(start.source_location().new_unexpected_token_error(token))
                     });
                     return Some(result.map_err(|e| (e, self.input.slice_from(start.position()))));
                 }
@@ -370,15 +370,13 @@ where
             let start = self.input.state();
 
             let at_keyword = match self.input.next_byte()? {
-                b'@' => {
-                    match self.input.next_including_whitespace_and_comments() {
-                        Ok(&Token::AtKeyword(ref name)) => Some(name.clone()),
-                        _ => {
-                            self.input.reset(&start);
-                            None
-                        },
+                b'@' => match self.input.next_including_whitespace_and_comments() {
+                    Ok(&Token::AtKeyword(ref name)) => Some(name.clone()),
+                    _ => {
+                        self.input.reset(&start);
+                        None
                     }
-                }
+                },
                 _ => None,
             };
 
@@ -465,14 +463,13 @@ fn parse_at_rule<'i, 't, P, E>(
 where
     P: AtRuleParser<'i, Error = E>,
 {
-    let location = input.current_source_location();
     let delimiters = Delimiter::Semicolon | Delimiter::CurlyBracketBlock;
     // FIXME: https://github.com/servo/rust-cssparser/issues/254
     let callback = |input: &mut Parser<'i, '_>| parser.parse_prelude(name, input);
     let result = parse_until_before(input, delimiters, callback);
     match result {
         Ok(AtRuleType::WithoutBlock(prelude)) => match input.next() {
-            Ok(&Token::Semicolon) | Err(_) => Ok(parser.rule_without_block(prelude, location)),
+            Ok(&Token::Semicolon) | Err(_) => Ok(parser.rule_without_block(prelude, start)),
             Ok(&Token::CurlyBracketBlock) => Err((
                 input.new_unexpected_token_error(Token::CurlyBracketBlock),
                 input.slice_from(start.position()),
@@ -484,7 +481,7 @@ where
                 Ok(&Token::CurlyBracketBlock) => {
                     // FIXME: https://github.com/servo/rust-cssparser/issues/254
                     let callback =
-                        |input: &mut Parser<'i, '_>| parser.parse_block(prelude, location, input);
+                        |input: &mut Parser<'i, '_>| parser.parse_block(prelude, start, input);
                     parse_nested_block(input, callback)
                         .map_err(|e| (e, input.slice_from(start.position())))
                 }
@@ -514,7 +511,7 @@ fn parse_qualified_rule<'i, 't, P, E>(
 where
     P: QualifiedRuleParser<'i, Error = E>,
 {
-    let location = input.current_source_location();
+    let start = input.state();
     // FIXME: https://github.com/servo/rust-cssparser/issues/254
     let callback = |input: &mut Parser<'i, '_>| parser.parse_prelude(input);
     let prelude = parse_until_before(input, Delimiter::CurlyBracketBlock, callback);
@@ -523,8 +520,7 @@ where
             // Do this here so that we consume the `{` even if the prelude is `Err`.
             let prelude = prelude?;
             // FIXME: https://github.com/servo/rust-cssparser/issues/254
-            let callback =
-                |input: &mut Parser<'i, '_>| parser.parse_block(prelude, location, input);
+            let callback = |input: &mut Parser<'i, '_>| parser.parse_block(prelude, &start, input);
             parse_nested_block(input, callback)
         }
         _ => unreachable!(),
diff --git a/third_party/rust/cssparser/src/tests.rs b/third_party/rust/cssparser/src/tests.rs
index e1114eb184..7aa6c462ed 100644
--- a/third_party/rust/cssparser/src/tests.rs
+++ b/third_party/rust/cssparser/src/tests.rs
@@ -16,8 +16,8 @@ use super::{
     parse_important, parse_nth, parse_one_declaration, parse_one_rule, stylesheet_encoding,
     AtRuleParser, AtRuleType, BasicParseError, BasicParseErrorKind, Color, CowRcStr,
     DeclarationListParser, DeclarationParser, Delimiter, EncodingSupport, ParseError,
-    ParseErrorKind, Parser, ParserInput, QualifiedRuleParser, RuleListParser, SourceLocation,
-    ToCss, Token, TokenSerializationType, UnicodeRange, RGBA,
+    ParseErrorKind, Parser, ParserInput, ParserState, QualifiedRuleParser, RuleListParser,
+    SourceLocation, ToCss, Token, TokenSerializationType, UnicodeRange, RGBA,
 };
 
 macro_rules! JArray {
@@ -469,11 +469,10 @@ fn serializer(preserve_comments: bool) {
                         _ => None,
                     };
                     if let Some(closing_token) = closing_token {
-                        let result: Result<_, ParseError<()>> =
-                            input.parse_nested_block(|input| {
-                                write_to(previous_token, input, string, preserve_comments);
-                                Ok(())
-                            });
+                        let result: Result<_, ParseError<()>> = input.parse_nested_block(|input| {
+                            write_to(previous_token, input, string, preserve_comments);
+                            Ok(())
+                        });
                         result.unwrap();
                         closing_token.to_css(string).unwrap();
                     }
@@ -947,7 +946,7 @@ impl<'i> AtRuleParser<'i> for JsonParser {
         }
     }
 
-    fn rule_without_block(&mut self, mut prelude: Vec<Value>, _location: SourceLocation) -> Value {
+    fn rule_without_block(&mut self, mut prelude: Vec<Value>, _: &ParserState) -> Value {
         prelude.push(Value::Null);
         Value::Array(prelude)
     }
@@ -955,7 +954,7 @@ impl<'i> AtRuleParser<'i> for JsonParser {
     fn parse_block<'t>(
         &mut self,
         mut prelude: Vec<Value>,
-        _location: SourceLocation,
+        _: &ParserState,
         input: &mut Parser<'i, 't>,
     ) -> Result<Value, ParseError<'i, ()>> {
         prelude.push(Value::Array(component_values_to_json(input)));
@@ -978,7 +977,7 @@ impl<'i> QualifiedRuleParser<'i> for JsonParser {
     fn parse_block<'t>(
         &mut self,
         prelude: Vec<Value>,
-        _location: SourceLocation,
+        _: &ParserState,
         input: &mut Parser<'i, 't>,
     ) -> Result<Value, ParseError<'i, ()>> {
         Ok(JArray![
diff --git a/third_party/rust/wast/.cargo-checksum.json b/third_party/rust/wast/.cargo-checksum.json
index f939b8d51b..982d04f8f3 100644
--- a/third_party/rust/wast/.cargo-checksum.json
+++ b/third_party/rust/wast/.cargo-checksum.json
@@ -1 +1 @@
-{"files":{"Cargo.toml":"24568dfb6c7dba37de238f00d47ccecb9e35a9a990183a0bf6fcf79d41faa06c","LICENSE-APACHE":"a60eea817514531668d7e00765731449fe14d059d3249e0bc93b36de45f759f2","LICENSE-MIT":"378f5840b258e2779c39418f3f2d7b2ba96f1c7917dd6be0713f88305dbda397","README.md":"ad8c69458e8f19f6a796d1d791d15f014a045ed11616fe27d987aa37b49599a0","src/ast/assert_expr.rs":"0f6310eccb8a602722a13b2230cfa56dbc470e4c0ba5eb300237a81dc1bfff43","src/ast/custom.rs":"4c926ba719013537696e075c9acd8043da92a833cd28b0d843abcbfb71080fc3","src/ast/event.rs":"18f5106a87635d50b5f3b13fedd08247d3eb8158df454790151acadd41d1e0ab","src/ast/export.rs":"f296bd3238c7f9886f626d619d3a41ff0797bd51cb7bec7053278a62d8cb5355","src/ast/expr.rs":"25b7e290cc6a3b7c416bf583b2869648cc690d0d1f26a0dcaf165b238bd4b373","src/ast/func.rs":"149d947957414548b65739212a2cf1362f0ec9ecdda517653ae83949aa8a89f5","src/ast/global.rs":"41b617886012277e7377600047611b78564c2c594d8c0792de1509b89676244f","src/ast/import.rs":"53f39569b8486cd5fde6b3a826bc7dc221fc925afa043e45a0a1550987332ba7","src/ast/memory.rs":"836135f8f5a7bffa90ddaad1a862b9133d9c0e680b63736daa3e2377c23cb785","src/ast/mod.rs":"74fb35f65f786e82f66e7c85c9102051923d6938f8615eb2b57c3363476ae153","src/ast/module.rs":"b25df1f5648ea6fd7666537d52aa18221d435301793e4e01c8affa4ebb0da7c9","src/ast/table.rs":"74e9a0588515dd039c76e8e775470ee752607f06ece3e05c7d6a4141adfb89ea","src/ast/token.rs":"cdaaa6f50a9868ed7d0ec7088447ba94e3df5c81d38bc471c55d0968c249f73c","src/ast/types.rs":"9066d8b425005a6a70d5ada5e0ae316bf9bcab8e685fd941cc6d0ebb7e204473","src/ast/wast.rs":"9e64d00baf809d09181a06073a3fa9ac5907ac8248336cfd2089735d017075e3","src/binary.rs":"7f97251d6dd80dde667559e25fe38cdd9f540468416532a796a1bafd77c4b44a","src/lexer.rs":"1e62516a22ca89aa9510d255c264a27776a86c831b4c22a1fd00d20272e7b96c","src/lib.rs":"5fc7614c3d4a89f5fcac328d4a82cecaa445e0620bdf6bd55308cb1ead73d297","src/parser.rs":"926838cf6a6bef8bdad1013194f3d9305b2237e9f7fb2df2fa8ca44f557483aa","src/resolve/expand.rs":"f7ecf82bb00d7c770f78f5582ec5427c25189ff11943c052572ffab2f996b12c","src/resolve/mod.rs":"916ce2c88f633e36609767f3bccfabef4438586e98475cc8f0e4cbea5d2caaf4","src/resolve/names.rs":"13e67ac425ae4fda25388102eab66aae4a2927c9ad80e1fe72ca9de6f8df8b22","src/resolve/tyexpand.rs":"69701f2fc566fd5da4b253643a91e3048dd3c41795d5fed6ac94a386ec01947a"},"package":"5b20abd8b4a26f7e0d4dd5e357e90a3d555ec190e94472c9b2b27c5b9777f9ae"}
\ No newline at end of file
+{"files":{"Cargo.toml":"b3728e0765da9b14c186bf2ef0dec6d6c88ccc7e918fadf46c1f29ba706ee3d8","LICENSE-APACHE":"a60eea817514531668d7e00765731449fe14d059d3249e0bc93b36de45f759f2","LICENSE-MIT":"378f5840b258e2779c39418f3f2d7b2ba96f1c7917dd6be0713f88305dbda397","README.md":"ad8c69458e8f19f6a796d1d791d15f014a045ed11616fe27d987aa37b49599a0","src/ast/assert_expr.rs":"0f6310eccb8a602722a13b2230cfa56dbc470e4c0ba5eb300237a81dc1bfff43","src/ast/custom.rs":"4c926ba719013537696e075c9acd8043da92a833cd28b0d843abcbfb71080fc3","src/ast/event.rs":"18f5106a87635d50b5f3b13fedd08247d3eb8158df454790151acadd41d1e0ab","src/ast/export.rs":"f296bd3238c7f9886f626d619d3a41ff0797bd51cb7bec7053278a62d8cb5355","src/ast/expr.rs":"cac2b8bcd4c1ac150c9a6d7c103ca5b9275eae0f48b8e4721b38832c0e5afda3","src/ast/func.rs":"149d947957414548b65739212a2cf1362f0ec9ecdda517653ae83949aa8a89f5","src/ast/global.rs":"41b617886012277e7377600047611b78564c2c594d8c0792de1509b89676244f","src/ast/import.rs":"53f39569b8486cd5fde6b3a826bc7dc221fc925afa043e45a0a1550987332ba7","src/ast/memory.rs":"836135f8f5a7bffa90ddaad1a862b9133d9c0e680b63736daa3e2377c23cb785","src/ast/mod.rs":"4fe54a05664de07b10c48c72c51dea581d8f4ea329ccddf17a0095870695a335","src/ast/module.rs":"b25df1f5648ea6fd7666537d52aa18221d435301793e4e01c8affa4ebb0da7c9","src/ast/table.rs":"df1b7877fb8867b35f1b6dbf8a5a036feb702cb99000c56767f9f3588f5fb1af","src/ast/token.rs":"c39ef468c61729434708d3a54cc8ba5117491ce15008ddb3eebd727e18a843a3","src/ast/types.rs":"647ce47678e156102926caa870062ca6048f496e35ff182d479fd2f0b7d2694d","src/ast/wast.rs":"9e64d00baf809d09181a06073a3fa9ac5907ac8248336cfd2089735d017075e3","src/binary.rs":"2f7060c94bf463fbc8f3ea27c526cb2e1e0b7112b3f266a83b040c75591f6430","src/lexer.rs":"1e62516a22ca89aa9510d255c264a27776a86c831b4c22a1fd00d20272e7b96c","src/lib.rs":"5fc7614c3d4a89f5fcac328d4a82cecaa445e0620bdf6bd55308cb1ead73d297","src/parser.rs":"926838cf6a6bef8bdad1013194f3d9305b2237e9f7fb2df2fa8ca44f557483aa","src/resolve/expand.rs":"f7ecf82bb00d7c770f78f5582ec5427c25189ff11943c052572ffab2f996b12c","src/resolve/mod.rs":"916ce2c88f633e36609767f3bccfabef4438586e98475cc8f0e4cbea5d2caaf4","src/resolve/names.rs":"44d730691a1f773d5f1609cb2d2dba2fb9307b084c6c3c45817d99de74b599f9","src/resolve/tyexpand.rs":"69701f2fc566fd5da4b253643a91e3048dd3c41795d5fed6ac94a386ec01947a"},"package":"8564a0c8f4d468d71c2b263dd1f675fa2cac6e7331ff8379cbb88cb79fcef8d1"}
\ No newline at end of file
diff --git a/third_party/rust/wast/Cargo.toml b/third_party/rust/wast/Cargo.toml
index 6acdb5c5e5..b16cf5e952 100644
--- a/third_party/rust/wast/Cargo.toml
+++ b/third_party/rust/wast/Cargo.toml
@@ -13,7 +13,7 @@
 [package]
 edition = "2018"
 name = "wast"
-version = "13.0.0"
+version = "16.0.0"
 authors = ["Alex Crichton <alex@alexcrichton.com>"]
 description = "Customizable Rust parsers for the WebAssembly Text formats WAT and WAST\n"
 homepage = "https://github.com/bytecodealliance/wat/tree/master/crates/wast"
diff --git a/third_party/rust/wast/src/ast/expr.rs b/third_party/rust/wast/src/ast/expr.rs
index 5152314b5b..1ed4bc7580 100644
--- a/third_party/rust/wast/src/ast/expr.rs
+++ b/third_party/rust/wast/src/ast/expr.rs
@@ -1,4 +1,4 @@
-use crate::ast::{self, kw};
+use crate::ast::{self, kw, RefType};
 use crate::parser::{Parse, Parser, Result};
 use std::mem;
 
@@ -411,8 +411,8 @@ instructions! {
         TableSize(TableArg<'a>) : [0xfc, 0x10] : "table.size",
         TableGrow(TableArg<'a>) : [0xfc, 0x0f] : "table.grow",
 
-        RefNull : [0xd0] : "ref.null",
-        RefIsNull : [0xd1] : "ref.is_null",
+        RefNull(RefType<'a>) : [0xd0] : "ref.null",
+        RefIsNull(RefType<'a>) : [0xd1] : "ref.is_null",
         RefHost(u32) : [0xff] : "ref.host", // only used in test harness
         RefFunc(ast::Index<'a>) : [0xd2] : "ref.func",
 
@@ -686,201 +686,198 @@ instructions! {
         I64AtomicRmw16CmpxchgU(MemArg<2>) : [0xfe, 0x4d] : "i64.atomic.rmw16.cmpxchg_u",
         I64AtomicRmw32CmpxchgU(MemArg<4>) : [0xfe, 0x4e] : "i64.atomic.rmw32.cmpxchg_u",
 
+        // proposal: simd
         V128Load(MemArg<16>) : [0xfd, 0x00] : "v128.load",
-        V128Store(MemArg<16>) : [0xfd, 0x01] : "v128.store",
-        V128Const(V128Const) : [0xfd, 0x02] : "v128.const",
+        I16x8Load8x8S(MemArg<8>) : [0xfd, 0x01] : "i16x8.load8x8_s",
+        I16x8Load8x8U(MemArg<8>) : [0xfd, 0x02] : "i16x8.load8x8_u",
+        I32x4Load16x4S(MemArg<8>) : [0xfd, 0x03] : "i32x4.load16x4_s",
+        I32x4Load16x4U(MemArg<8>) : [0xfd, 0x04] : "i32x4.load16x4_u",
+        I64x2Load32x2S(MemArg<8>) : [0xfd, 0x05] : "i64x2.load32x2_s",
+        I64x2Load32x2U(MemArg<8>) : [0xfd, 0x06] : "i64x2.load32x2_u",
+        V8x16LoadSplat(MemArg<1>) : [0xfd, 0x07] : "v8x16.load_splat",
+        V16x8LoadSplat(MemArg<2>) : [0xfd, 0x08] : "v16x8.load_splat",
+        V32x4LoadSplat(MemArg<4>) : [0xfd, 0x09] : "v32x4.load_splat",
+        V64x2LoadSplat(MemArg<8>) : [0xfd, 0x0a] : "v64x2.load_splat",
+        V128Store(MemArg<16>) : [0xfd, 0x0b] : "v128.store",
 
-        I8x16Splat : [0xfd, 0x04] : "i8x16.splat",
-        I8x16ExtractLaneS(u8) : [0xfd, 0x05] : "i8x16.extract_lane_s",
-        I8x16ExtractLaneU(u8) : [0xfd, 0x06] : "i8x16.extract_lane_u",
-        I8x16ReplaceLane(u8) : [0xfd, 0x07] : "i8x16.replace_lane",
-        I16x8Splat : [0xfd, 0x08] : "i16x8.splat",
-        I16x8ExtractLaneS(u8) : [0xfd, 0x09] : "i16x8.extract_lane_s",
-        I16x8ExtractLaneU(u8) : [0xfd, 0x0a] : "i16x8.extract_lane_u",
-        I16x8ReplaceLane(u8) : [0xfd, 0x0b] : "i16x8.replace_lane",
-        I32x4Splat : [0xfd, 0x0c] : "i32x4.splat",
-        I32x4ExtractLane(u8) : [0xfd, 0x0d] : "i32x4.extract_lane",
-        I32x4ReplaceLane(u8) : [0xfd, 0x0e] : "i32x4.replace_lane",
-        I64x2Splat : [0xfd, 0x0f] : "i64x2.splat",
-        I64x2ExtractLane(u8) : [0xfd, 0x10] : "i64x2.extract_lane",
-        I64x2ReplaceLane(u8) : [0xfd, 0x11] : "i64x2.replace_lane",
-        F32x4Splat : [0xfd, 0x12] : "f32x4.splat",
-        F32x4ExtractLane(u8) : [0xfd, 0x13] : "f32x4.extract_lane",
-        F32x4ReplaceLane(u8) : [0xfd, 0x14] : "f32x4.replace_lane",
-        F64x2Splat : [0xfd, 0x15] : "f64x2.splat",
-        F64x2ExtractLane(u8) : [0xfd, 0x16] : "f64x2.extract_lane",
-        F64x2ReplaceLane(u8) : [0xfd, 0x17] : "f64x2.replace_lane",
+        V128Const(V128Const) : [0xfd, 0x0c] : "v128.const",
+        V8x16Shuffle(V8x16Shuffle) : [0xfd, 0x0d] : "v8x16.shuffle",
+        V8x16Swizzle : [0xfd, 0x0e] : "v8x16.swizzle",
 
-        I8x16Eq : [0xfd, 0x18] : "i8x16.eq",
-        I8x16Ne : [0xfd, 0x19] : "i8x16.ne",
-        I8x16LtS : [0xfd, 0x1a] : "i8x16.lt_s",
-        I8x16LtU : [0xfd, 0x1b] : "i8x16.lt_u",
-        I8x16GtS : [0xfd, 0x1c] : "i8x16.gt_s",
-        I8x16GtU : [0xfd, 0x1d] : "i8x16.gt_u",
-        I8x16LeS : [0xfd, 0x1e] : "i8x16.le_s",
-        I8x16LeU : [0xfd, 0x1f] : "i8x16.le_u",
-        I8x16GeS : [0xfd, 0x20] : "i8x16.ge_s",
-        I8x16GeU : [0xfd, 0x21] : "i8x16.ge_u",
-        I16x8Eq : [0xfd, 0x22] : "i16x8.eq",
-        I16x8Ne : [0xfd, 0x23] : "i16x8.ne",
-        I16x8LtS : [0xfd, 0x24] : "i16x8.lt_s",
-        I16x8LtU : [0xfd, 0x25] : "i16x8.lt_u",
-        I16x8GtS : [0xfd, 0x26] : "i16x8.gt_s",
-        I16x8GtU : [0xfd, 0x27] : "i16x8.gt_u",
-        I16x8LeS : [0xfd, 0x28] : "i16x8.le_s",
-        I16x8LeU : [0xfd, 0x29] : "i16x8.le_u",
-        I16x8GeS : [0xfd, 0x2a] : "i16x8.ge_s",
-        I16x8GeU : [0xfd, 0x2b] : "i16x8.ge_u",
-        I32x4Eq : [0xfd, 0x2c] : "i32x4.eq",
-        I32x4Ne : [0xfd, 0x2d] : "i32x4.ne",
-        I32x4LtS : [0xfd, 0x2e] : "i32x4.lt_s",
-        I32x4LtU : [0xfd, 0x2f] : "i32x4.lt_u",
-        I32x4GtS : [0xfd, 0x30] : "i32x4.gt_s",
-        I32x4GtU : [0xfd, 0x31] : "i32x4.gt_u",
-        I32x4LeS : [0xfd, 0x32] : "i32x4.le_s",
-        I32x4LeU : [0xfd, 0x33] : "i32x4.le_u",
-        I32x4GeS : [0xfd, 0x34] : "i32x4.ge_s",
-        I32x4GeU : [0xfd, 0x35] : "i32x4.ge_u",
+        I8x16Splat : [0xfd, 0x0f] : "i8x16.splat",
+        I16x8Splat : [0xfd, 0x10] : "i16x8.splat",
+        I32x4Splat : [0xfd, 0x11] : "i32x4.splat",
+        I64x2Splat : [0xfd, 0x12] : "i64x2.splat",
+        F32x4Splat : [0xfd, 0x13] : "f32x4.splat",
+        F64x2Splat : [0xfd, 0x14] : "f64x2.splat",
 
-        F32x4Eq : [0xfd, 0x40] : "f32x4.eq",
-        F32x4Ne : [0xfd, 0x41] : "f32x4.ne",
-        F32x4Lt : [0xfd, 0x42] : "f32x4.lt",
-        F32x4Gt : [0xfd, 0x43] : "f32x4.gt",
-        F32x4Le : [0xfd, 0x44] : "f32x4.le",
-        F32x4Ge : [0xfd, 0x45] : "f32x4.ge",
-        F64x2Eq : [0xfd, 0x46] : "f64x2.eq",
-        F64x2Ne : [0xfd, 0x47] : "f64x2.ne",
-        F64x2Lt : [0xfd, 0x48] : "f64x2.lt",
-        F64x2Gt : [0xfd, 0x49] : "f64x2.gt",
-        F64x2Le : [0xfd, 0x4a] : "f64x2.le",
-        F64x2Ge : [0xfd, 0x4b] : "f64x2.ge",
+        I8x16ExtractLaneS(u8) : [0xfd, 0x15] : "i8x16.extract_lane_s",
+        I8x16ExtractLaneU(u8) : [0xfd, 0x16] : "i8x16.extract_lane_u",
+        I8x16ReplaceLane(u8) : [0xfd, 0x17] : "i8x16.replace_lane",
+        I16x8ExtractLaneS(u8) : [0xfd, 0x18] : "i16x8.extract_lane_s",
+        I16x8ExtractLaneU(u8) : [0xfd, 0x19] : "i16x8.extract_lane_u",
+        I16x8ReplaceLane(u8) : [0xfd, 0x1a] : "i16x8.replace_lane",
+        I32x4ExtractLane(u8) : [0xfd, 0x1b] : "i32x4.extract_lane",
+        I32x4ReplaceLane(u8) : [0xfd, 0x1c] : "i32x4.replace_lane",
+        I64x2ExtractLane(u8) : [0xfd, 0x1d] : "i64x2.extract_lane",
+        I64x2ReplaceLane(u8) : [0xfd, 0x1e] : "i64x2.replace_lane",
+        F32x4ExtractLane(u8) : [0xfd, 0x1f] : "f32x4.extract_lane",
+        F32x4ReplaceLane(u8) : [0xfd, 0x20] : "f32x4.replace_lane",
+        F64x2ExtractLane(u8) : [0xfd, 0x21] : "f64x2.extract_lane",
+        F64x2ReplaceLane(u8) : [0xfd, 0x22] : "f64x2.replace_lane",
 
-        V128Not : [0xfd, 0x4c] : "v128.not",
-        V128And : [0xfd, 0x4d] : "v128.and",
-        V128Or : [0xfd, 0x4e] : "v128.or",
-        V128Xor : [0xfd, 0x4f] : "v128.xor",
-        V128Bitselect : [0xfd, 0x50] : "v128.bitselect",
+        I8x16Eq : [0xfd, 0x23] : "i8x16.eq",
+        I8x16Ne : [0xfd, 0x24] : "i8x16.ne",
+        I8x16LtS : [0xfd, 0x25] : "i8x16.lt_s",
+        I8x16LtU : [0xfd, 0x26] : "i8x16.lt_u",
+        I8x16GtS : [0xfd, 0x27] : "i8x16.gt_s",
+        I8x16GtU : [0xfd, 0x28] : "i8x16.gt_u",
+        I8x16LeS : [0xfd, 0x29] : "i8x16.le_s",
+        I8x16LeU : [0xfd, 0x2a] : "i8x16.le_u",
+        I8x16GeS : [0xfd, 0x2b] : "i8x16.ge_s",
+        I8x16GeU : [0xfd, 0x2c] : "i8x16.ge_u",
+        I16x8Eq : [0xfd, 0x2d] : "i16x8.eq",
+        I16x8Ne : [0xfd, 0x2e] : "i16x8.ne",
+        I16x8LtS : [0xfd, 0x2f] : "i16x8.lt_s",
+        I16x8LtU : [0xfd, 0x30] : "i16x8.lt_u",
+        I16x8GtS : [0xfd, 0x31] : "i16x8.gt_s",
+        I16x8GtU : [0xfd, 0x32] : "i16x8.gt_u",
+        I16x8LeS : [0xfd, 0x33] : "i16x8.le_s",
+        I16x8LeU : [0xfd, 0x34] : "i16x8.le_u",
+        I16x8GeS : [0xfd, 0x35] : "i16x8.ge_s",
+        I16x8GeU : [0xfd, 0x36] : "i16x8.ge_u",
+        I32x4Eq : [0xfd, 0x37] : "i32x4.eq",
+        I32x4Ne : [0xfd, 0x38] : "i32x4.ne",
+        I32x4LtS : [0xfd, 0x39] : "i32x4.lt_s",
+        I32x4LtU : [0xfd, 0x3a] : "i32x4.lt_u",
+        I32x4GtS : [0xfd, 0x3b] : "i32x4.gt_s",
+        I32x4GtU : [0xfd, 0x3c] : "i32x4.gt_u",
+        I32x4LeS : [0xfd, 0x3d] : "i32x4.le_s",
+        I32x4LeU : [0xfd, 0x3e] : "i32x4.le_u",
+        I32x4GeS : [0xfd, 0x3f] : "i32x4.ge_s",
+        I32x4GeU : [0xfd, 0x40] : "i32x4.ge_u",
 
-        I8x16Neg : [0xfd, 0x51] : "i8x16.neg",
-        I8x16AnyTrue : [0xfd, 0x52] : "i8x16.any_true",
-        I8x16AllTrue : [0xfd, 0x53] : "i8x16.all_true",
-        I8x16Shl : [0xfd, 0x54] : "i8x16.shl",
-        I8x16ShrS : [0xfd, 0x55] : "i8x16.shr_s",
-        I8x16ShrU : [0xfd, 0x56] : "i8x16.shr_u",
-        I8x16Add : [0xfd, 0x57] : "i8x16.add",
-        I8x16AddSaturateS : [0xfd, 0x58] : "i8x16.add_saturate_s",
-        I8x16AddSaturateU : [0xfd, 0x59] : "i8x16.add_saturate_u",
-        I8x16Sub : [0xfd, 0x5a] : "i8x16.sub",
-        I8x16SubSaturateS : [0xfd, 0x5b] : "i8x16.sub_saturate_s",
-        I8x16SubSaturateU : [0xfd, 0x5c] : "i8x16.sub_saturate_u",
-        I8x16Mul : [0xfd, 0x5d] : "i8x16.mul",
-        I8x16MinS : [0xfd, 0x5e] : "i8x16.min_s",
-        I8x16MinU : [0xfd, 0x5f] : "i8x16.min_u",
-        I8x16MaxS : [0xfd, 0x60] : "i8x16.max_s",
-        I8x16MaxU : [0xfd, 0x61] : "i8x16.max_u",
+        F32x4Eq : [0xfd, 0x41] : "f32x4.eq",
+        F32x4Ne : [0xfd, 0x42] : "f32x4.ne",
+        F32x4Lt : [0xfd, 0x43] : "f32x4.lt",
+        F32x4Gt : [0xfd, 0x44] : "f32x4.gt",
+        F32x4Le : [0xfd, 0x45] : "f32x4.le",
+        F32x4Ge : [0xfd, 0x46] : "f32x4.ge",
+        F64x2Eq : [0xfd, 0x47] : "f64x2.eq",
+        F64x2Ne : [0xfd, 0x48] : "f64x2.ne",
+        F64x2Lt : [0xfd, 0x49] : "f64x2.lt",
+        F64x2Gt : [0xfd, 0x4a] : "f64x2.gt",
+        F64x2Le : [0xfd, 0x4b] : "f64x2.le",
+        F64x2Ge : [0xfd, 0x4c] : "f64x2.ge",
 
-        I16x8Neg : [0xfd, 0x62] : "i16x8.neg",
-        I16x8AnyTrue : [0xfd, 0x63] : "i16x8.any_true",
-        I16x8AllTrue : [0xfd, 0x64] : "i16x8.all_true",
-        I16x8Shl : [0xfd, 0x65] : "i16x8.shl",
-        I16x8ShrS : [0xfd, 0x66] : "i16x8.shr_s",
-        I16x8ShrU : [0xfd, 0x67] : "i16x8.shr_u",
-        I16x8Add : [0xfd, 0x68] : "i16x8.add",
-        I16x8AddSaturateS : [0xfd, 0x69] : "i16x8.add_saturate_s",
-        I16x8AddSaturateU : [0xfd, 0x6a] : "i16x8.add_saturate_u",
-        I16x8Sub : [0xfd, 0x6b] : "i16x8.sub",
-        I16x8SubSaturateS : [0xfd, 0x6c] : "i16x8.sub_saturate_s",
-        I16x8SubSaturateU : [0xfd, 0x6d] : "i16x8.sub_saturate_u",
-        I16x8Mul : [0xfd, 0x6e] : "i16x8.mul",
-        I16x8MinS : [0xfd, 0x6f] : "i16x8.min_s",
-        I16x8MinU : [0xfd, 0x70] : "i16x8.min_u",
-        I16x8MaxS : [0xfd, 0x71] : "i16x8.max_s",
-        I16x8MaxU : [0xfd, 0x72] : "i16x8.max_u",
+        V128Not : [0xfd, 0x4d] : "v128.not",
+        V128And : [0xfd, 0x4e] : "v128.and",
+        V128Andnot : [0xfd, 0x4f] : "v128.andnot",
+        V128Or : [0xfd, 0x50] : "v128.or",
+        V128Xor : [0xfd, 0x51] : "v128.xor",
+        V128Bitselect : [0xfd, 0x52] : "v128.bitselect",
 
-        I32x4Neg : [0xfd, 0x73] : "i32x4.neg",
-        I32x4AnyTrue : [0xfd, 0x74] : "i32x4.any_true",
-        I32x4AllTrue : [0xfd, 0x75] : "i32x4.all_true",
-        I32x4Shl : [0xfd, 0x76] : "i32x4.shl",
-        I32x4ShrS : [0xfd, 0x77] : "i32x4.shr_s",
-        I32x4ShrU : [0xfd, 0x78] : "i32x4.shr_u",
-        I32x4Add : [0xfd, 0x79] : "i32x4.add",
-        I32x4Sub : [0xfd, 0x7c] : "i32x4.sub",
-        I32x4Mul : [0xfd, 0x7f] : "i32x4.mul",
-        I32x4MinS : [0xfd, 0x80] : "i32x4.min_s",
-        I32x4MinU : [0xfd, 0x81] : "i32x4.min_u",
-        I32x4MaxS : [0xfd, 0x82] : "i32x4.max_s",
-        I32x4MaxU : [0xfd, 0x83] : "i32x4.max_u",
+        I8x16Abs : [0xfd, 0x60] : "i8x16.abs",
+        I8x16Neg : [0xfd, 0x61] : "i8x16.neg",
+        I8x16AnyTrue : [0xfd, 0x62] : "i8x16.any_true",
+        I8x16AllTrue : [0xfd, 0x63] : "i8x16.all_true",
+        I8x16NarrowI16x8S : [0xfd, 0x65] : "i8x16.narrow_i16x8_s",
+        I8x16NarrowI16x8U : [0xfd, 0x66] : "i8x16.narrow_i16x8_u",
+        I8x16Shl : [0xfd, 0x6b] : "i8x16.shl",
+        I8x16ShrS : [0xfd, 0x6c] : "i8x16.shr_s",
+        I8x16ShrU : [0xfd, 0x6d] : "i8x16.shr_u",
+        I8x16Add : [0xfd, 0x6e] : "i8x16.add",
+        I8x16AddSaturateS : [0xfd, 0x6f] : "i8x16.add_saturate_s",
+        I8x16AddSaturateU : [0xfd, 0x70] : "i8x16.add_saturate_u",
+        I8x16Sub : [0xfd, 0x71] : "i8x16.sub",
+        I8x16SubSaturateS : [0xfd, 0x72] : "i8x16.sub_saturate_s",
+        I8x16SubSaturateU : [0xfd, 0x73] : "i8x16.sub_saturate_u",
+        I8x16MinS : [0xfd, 0x76] : "i8x16.min_s",
+        I8x16MinU : [0xfd, 0x77] : "i8x16.min_u",
+        I8x16MaxS : [0xfd, 0x78] : "i8x16.max_s",
+        I8x16MaxU : [0xfd, 0x79] : "i8x16.max_u",
+        I8x16AvgrU : [0xfd, 0x7b] : "i8x16.avgr_u",
 
-        I64x2Neg : [0xfd, 0x84] : "i64x2.neg",
-        I64x2AnyTrue : [0xfd, 0x85] : "i64x2.any_true",
-        I64x2AllTrue : [0xfd, 0x86] : "i64x2.all_true",
-        I64x2Shl : [0xfd, 0x87] : "i64x2.shl",
-        I64x2ShrS : [0xfd, 0x88] : "i64x2.shr_s",
-        I64x2ShrU : [0xfd, 0x89] : "i64x2.shr_u",
-        I64x2Add : [0xfd, 0x8a] : "i64x2.add",
-        I64x2Sub : [0xfd, 0x8d] : "i64x2.sub",
-        I64x2Mul : [0xfd, 0x90] : "i64x2.mul",
+        I16x8Abs : [0xfd, 0x80] : "i16x8.abs",
+        I16x8Neg : [0xfd, 0x81] : "i16x8.neg",
+        I16x8AnyTrue : [0xfd, 0x82] : "i16x8.any_true",
+        I16x8AllTrue : [0xfd, 0x83] : "i16x8.all_true",
+        I16x8NarrowI32x4S : [0xfd, 0x85] : "i16x8.narrow_i32x4_s",
+        I16x8NarrowI32x4U : [0xfd, 0x86] : "i16x8.narrow_i32x4_u",
+        I16x8WidenLowI8x16S : [0xfd, 0x87] : "i16x8.widen_low_i8x16_s",
+        I16x8WidenHighI8x16S : [0xfd, 0x88] : "i16x8.widen_high_i8x16_s",
+        I16x8WidenLowI8x16U : [0xfd, 0x89] : "i16x8.widen_low_i8x16_u",
+        I16x8WidenHighI8x16u : [0xfd, 0x8a] : "i16x8.widen_high_i8x16_u",
+        I16x8Shl : [0xfd, 0x8b] : "i16x8.shl",
+        I16x8ShrS : [0xfd, 0x8c] : "i16x8.shr_s",
+        I16x8ShrU : [0xfd, 0x8d] : "i16x8.shr_u",
+        I16x8Add : [0xfd, 0x8e] : "i16x8.add",
+        I16x8AddSaturateS : [0xfd, 0x8f] : "i16x8.add_saturate_s",
+        I16x8AddSaturateU : [0xfd, 0x90] : "i16x8.add_saturate_u",
+        I16x8Sub : [0xfd, 0x91] : "i16x8.sub",
+        I16x8SubSaturateS : [0xfd, 0x92] : "i16x8.sub_saturate_s",
+        I16x8SubSaturateU : [0xfd, 0x93] : "i16x8.sub_saturate_u",
+        I16x8Mul : [0xfd, 0x95] : "i16x8.mul",
+        I16x8MinS : [0xfd, 0x96] : "i16x8.min_s",
+        I16x8MinU : [0xfd, 0x97] : "i16x8.min_u",
+        I16x8MaxS : [0xfd, 0x98] : "i16x8.max_s",
+        I16x8MaxU : [0xfd, 0x99] : "i16x8.max_u",
+        I16x8AvgrU : [0xfd, 0x9b] : "i16x8.avgr_u",
 
-        F32x4Abs : [0xfd, 0x95] : "f32x4.abs",
-        F32x4Neg : [0xfd, 0x96] : "f32x4.neg",
-        F32x4Sqrt : [0xfd, 0x97] : "f32x4.sqrt",
-        F32x4Add : [0xfd, 0x9a] : "f32x4.add",
-        F32x4Sub : [0xfd, 0x9b] : "f32x4.sub",
-        F32x4Mul : [0xfd, 0x9c] : "f32x4.mul",
-        F32x4Div : [0xfd, 0x9d] : "f32x4.div",
-        F32x4Min : [0xfd, 0x9e] : "f32x4.min",
-        F32x4Max : [0xfd, 0x9f] : "f32x4.max",
+        I32x4Abs : [0xfd, 0xa0] : "i32x4.abs",
+        I32x4Neg : [0xfd, 0xa1] : "i32x4.neg",
+        I32x4AnyTrue : [0xfd, 0xa2] : "i32x4.any_true",
+        I32x4AllTrue : [0xfd, 0xa3] : "i32x4.all_true",
+        I32x4WidenLowI16x8S : [0xfd, 0xa7] : "i32x4.widen_low_i16x8_s",
+        I32x4WidenHighI16x8S : [0xfd, 0xa8] : "i32x4.widen_high_i16x8_s",
+        I32x4WidenLowI16x8U : [0xfd, 0xa9] : "i32x4.widen_low_i16x8_u",
+        I32x4WidenHighI16x8u : [0xfd, 0xaa] : "i32x4.widen_high_i16x8_u",
+        I32x4Shl : [0xfd, 0xab] : "i32x4.shl",
+        I32x4ShrS : [0xfd, 0xac] : "i32x4.shr_s",
+        I32x4ShrU : [0xfd, 0xad] : "i32x4.shr_u",
+        I32x4Add : [0xfd, 0xae] : "i32x4.add",
+        I32x4Sub : [0xfd, 0xb1] : "i32x4.sub",
+        I32x4DotI16x8S : [0xfd, 0xb4] : "i32x4.dot_i8x16_s",
+        I32x4Mul : [0xfd, 0xb5] : "i32x4.mul",
+        I32x4MinS : [0xfd, 0xb6] : "i32x4.min_s",
+        I32x4MinU : [0xfd, 0xb7] : "i32x4.min_u",
+        I32x4MaxS : [0xfd, 0xb8] : "i32x4.max_s",
+        I32x4MaxU : [0xfd, 0xb9] : "i32x4.max_u",
 
-        F64x2Abs : [0xfd, 0xa0] : "f64x2.abs",
-        F64x2Neg : [0xfd, 0xa1] : "f64x2.neg",
-        F64x2Sqrt : [0xfd, 0xa2] : "f64x2.sqrt",
-        F64x2Add : [0xfd, 0xa5] : "f64x2.add",
-        F64x2Sub : [0xfd, 0xa6] : "f64x2.sub",
-        F64x2Mul : [0xfd, 0xa7] : "f64x2.mul",
-        F64x2Div : [0xfd, 0xa8] : "f64x2.div",
-        F64x2Min : [0xfd, 0xa9] : "f64x2.min",
-        F64x2Max : [0xfd, 0xaa] : "f64x2.max",
+        I64x2Neg : [0xfd, 0xc1] : "i64x2.neg",
+        I64x2Shl : [0xfd, 0xcb] : "i64x2.shl",
+        I64x2ShrS : [0xfd, 0xcc] : "i64x2.shr_s",
+        I64x2ShrU : [0xfd, 0xcd] : "i64x2.shr_u",
+        I64x2Add : [0xfd, 0xce] : "i64x2.add",
+        I64x2Sub : [0xfd, 0xd1] : "i64x2.sub",
+        I64x2Mul : [0xfd, 0xd5] : "i64x2.mul",
 
-        I32x4TruncSatF32x4S : [0xfd, 0xab] : "i32x4.trunc_sat_f32x4_s",
-        I32x4TruncSatF32x4U : [0xfd, 0xac] : "i32x4.trunc_sat_f32x4_u",
-        F32x4ConvertI32x4S : [0xfd, 0xaf] : "f32x4.convert_i32x4_s",
-        F32x4ConvertI32x4U : [0xfd, 0xb0] : "f32x4.convert_i32x4_u",
-        V8x16Swizzle : [0xfd, 0xc0] : "v8x16.swizzle",
-        V8x16Shuffle(V8x16Shuffle) : [0xfd, 0x03] : "v8x16.shuffle",
-        V8x16LoadSplat(MemArg<1>) : [0xfd, 0xc2] : "v8x16.load_splat",
-        V16x8LoadSplat(MemArg<2>) : [0xfd, 0xc3] : "v16x8.load_splat",
-        V32x4LoadSplat(MemArg<4>) : [0xfd, 0xc4] : "v32x4.load_splat",
-        V64x2LoadSplat(MemArg<8>) : [0xfd, 0xc5] : "v64x2.load_splat",
+        F32x4Abs : [0xfd, 0xe0] : "f32x4.abs",
+        F32x4Neg : [0xfd, 0xe1] : "f32x4.neg",
+        F32x4Sqrt : [0xfd, 0xe3] : "f32x4.sqrt",
+        F32x4Add : [0xfd, 0xe4] : "f32x4.add",
+        F32x4Sub : [0xfd, 0xe5] : "f32x4.sub",
+        F32x4Mul : [0xfd, 0xe6] : "f32x4.mul",
+        F32x4Div : [0xfd, 0xe7] : "f32x4.div",
+        F32x4Min : [0xfd, 0xe8] : "f32x4.min",
+        F32x4Max : [0xfd, 0xe9] : "f32x4.max",
 
-        I8x16NarrowI16x8S : [0xfd, 0xc6] : "i8x16.narrow_i16x8_s",
-        I8x16NarrowI16x8U : [0xfd, 0xc7] : "i8x16.narrow_i16x8_u",
-        I16x8NarrowI32x4S : [0xfd, 0xc8] : "i16x8.narrow_i32x4_s",
-        I16x8NarrowI32x4U : [0xfd, 0xc9] : "i16x8.narrow_i32x4_u",
+        F64x2Abs : [0xfd, 0xec] : "f64x2.abs",
+        F64x2Neg : [0xfd, 0xed] : "f64x2.neg",
+        F64x2Sqrt : [0xfd, 0xef] : "f64x2.sqrt",
+        F64x2Add : [0xfd, 0xf0] : "f64x2.add",
+        F64x2Sub : [0xfd, 0xf1] : "f64x2.sub",
+        F64x2Mul : [0xfd, 0xf2] : "f64x2.mul",
+        F64x2Div : [0xfd, 0xf3] : "f64x2.div",
+        F64x2Min : [0xfd, 0xf4] : "f64x2.min",
+        F64x2Max : [0xfd, 0xf5] : "f64x2.max",
 
-        I16x8WidenLowI8x16S : [0xfd, 0xca] : "i16x8.widen_low_i8x16_s",
-        I16x8WidenHighI8x16S : [0xfd, 0xcb] : "i16x8.widen_high_i8x16_s",
-        I16x8WidenLowI8x16U : [0xfd, 0xcc] : "i16x8.widen_low_i8x16_u",
-        I16x8WidenHighI8x16u : [0xfd, 0xcd] : "i16x8.widen_high_i8x16_u",
-        I32x4WidenLowI16x8S : [0xfd, 0xce] : "i32x4.widen_low_i16x8_s",
-        I32x4WidenHighI16x8S : [0xfd, 0xcf] : "i32x4.widen_high_i16x8_s",
-        I32x4WidenLowI16x8U : [0xfd, 0xd0] : "i32x4.widen_low_i16x8_u",
-        I32x4WidenHighI16x8u : [0xfd, 0xd1] : "i32x4.widen_high_i16x8_u",
-
-        I16x8Load8x8S(MemArg<8>) : [0xfd, 0xd2] : "i16x8.load8x8_s",
-        I16x8Load8x8U(MemArg<8>) : [0xfd, 0xd3] : "i16x8.load8x8_u",
-        I32x4Load16x4S(MemArg<8>) : [0xfd, 0xd4] : "i32x4.load16x4_s",
-        I32x4Load16x4U(MemArg<8>) : [0xfd, 0xd5] : "i32x4.load16x4_u",
-        I64x2Load32x2S(MemArg<8>) : [0xfd, 0xd6] : "i64x2.load32x2_s",
-        I64x2Load32x2U(MemArg<8>) : [0xfd, 0xd7] : "i64x2.load32x2_u",
-        V128Andnot : [0xfd, 0xd8] : "v128.andnot",
-
-        I8x16AvgrU : [0xfd, 0xd9] : "i8x16.avgr_u",
-        I16x8AvgrU : [0xfd, 0xda] : "i16x8.avgr_u",
-
-        I8x16Abs : [0xfd, 0xe1] : "i8x16.abs",
-        I16x8Abs : [0xfd, 0xe2] : "i16x8.abs",
-        I32x4Abs : [0xfd, 0xe3] : "i32x4.abs",
+        I32x4TruncSatF32x4S : [0xfd, 0xf8] : "i32x4.trunc_sat_f32x4_s",
+        I32x4TruncSatF32x4U : [0xfd, 0xf9] : "i32x4.trunc_sat_f32x4_u",
+        F32x4ConvertI32x4S : [0xfd, 0xfa] : "f32x4.convert_i32x4_s",
+        F32x4ConvertI32x4U : [0xfd, 0xfb] : "f32x4.convert_i32x4_u",
 
+        // Exception handling proposal
         Try(BlockType<'a>) : [0x06] : "try",
         Catch : [0x07] : "catch",
         Throw(ast::Index<'a>) : [0x08] : "throw",
diff --git a/third_party/rust/wast/src/ast/mod.rs b/third_party/rust/wast/src/ast/mod.rs
index 35eaf298c0..07cd6dfb59 100644
--- a/third_party/rust/wast/src/ast/mod.rs
+++ b/third_party/rust/wast/src/ast/mod.rs
@@ -348,6 +348,8 @@ pub mod kw {
     custom_keyword!(exn);
     custom_keyword!(exnref);
     custom_keyword!(export);
+    custom_keyword!(r#extern = "extern");
+    custom_keyword!(externref);
     custom_keyword!(eq);
     custom_keyword!(eqref);
     custom_keyword!(f32);
diff --git a/third_party/rust/wast/src/ast/table.rs b/third_party/rust/wast/src/ast/table.rs
index a59bb3a2aa..eee4b24dbf 100644
--- a/third_party/rust/wast/src/ast/table.rs
+++ b/third_party/rust/wast/src/ast/table.rs
@@ -208,12 +208,12 @@ impl<'a> ElemPayload<'a> {
             let func = parser.parens(|p| match p.parse::<Option<kw::item>>()? {
                 Some(_) => {
                     if parser.peek::<ast::LParen>() {
-                        parser.parens(parse_ref_func)
+                        parser.parens(|p| parse_ref_func(p, ty))
                     } else {
-                        parse_ref_func(parser)
+                        parse_ref_func(parser, ty)
                     }
                 }
-                None => parse_ref_func(p),
+                None => parse_ref_func(parser, ty),
             })?;
             exprs.push(func);
         }
@@ -221,10 +221,14 @@ impl<'a> ElemPayload<'a> {
     }
 }
 
-fn parse_ref_func<'a>(parser: Parser<'a>) -> Result<Option<ast::Index<'a>>> {
+fn parse_ref_func<'a>(parser: Parser<'a>, ty: ast::TableElemType) -> Result<Option<ast::Index<'a>>> {
     let mut l = parser.lookahead1();
     if l.peek::<kw::ref_null>() {
         parser.parse::<kw::ref_null>()?;
+        let null_ty: ast::RefType = parser.parse()?;
+        if null_ty != ty.into() {
+            return Err(parser.error("elem segment item doesn't match elem segment type"));
+        }
         Ok(None)
     } else if l.peek::<kw::ref_func>() {
         parser.parse::<kw::ref_func>()?;
diff --git a/third_party/rust/wast/src/ast/token.rs b/third_party/rust/wast/src/ast/token.rs
index f08047f884..1247956ada 100644
--- a/third_party/rust/wast/src/ast/token.rs
+++ b/third_party/rust/wast/src/ast/token.rs
@@ -12,6 +12,11 @@ pub struct Span {
 }
 
 impl Span {
+    /// Construct a `Span` from a byte offset in the source file.
+    pub fn from_offset(offset: usize) -> Self {
+        Span { offset }
+    }
+
     /// Returns the line/column information of this span within `text`.
     /// Line and column numbers are 0-indexed. User presentation is typically
     /// 1-indexed, but 0-indexing is appropriate for internal use with
diff --git a/third_party/rust/wast/src/ast/types.rs b/third_party/rust/wast/src/ast/types.rs
index e0afc467e9..797792e6ad 100644
--- a/third_party/rust/wast/src/ast/types.rs
+++ b/third_party/rust/wast/src/ast/types.rs
@@ -12,14 +12,7 @@ pub enum ValType<'a> {
     V128,
     I8,
     I16,
-    Funcref,
-    Anyref,
-    Nullref,
-    Exnref,
-    Ref(ast::Index<'a>),
-    Optref(ast::Index<'a>),
-    Eqref,
-    I31ref,
+    Ref(RefType<'a>),
     Rtt(ast::Index<'a>),
 }
 
@@ -49,52 +42,27 @@ impl<'a> Parse<'a> for ValType<'a> {
             Ok(ValType::I16)
         } else if l.peek::<kw::funcref>() {
             parser.parse::<kw::funcref>()?;
-            Ok(ValType::Funcref)
+            Ok(ValType::Ref(RefType::Func))
         } else if l.peek::<kw::anyfunc>() {
             parser.parse::<kw::anyfunc>()?;
-            Ok(ValType::Funcref)
+            Ok(ValType::Ref(RefType::Func))
+        } else if l.peek::<kw::externref>() {
+            parser.parse::<kw::externref>()?;
+            Ok(ValType::Ref(RefType::Extern))
         } else if l.peek::<kw::anyref>() {
+            // Parse `anyref` as an alias of `externref` until all tests are
+            // ported to use the new name
             parser.parse::<kw::anyref>()?;
-            Ok(ValType::Anyref)
-        } else if l.peek::<kw::nullref>() {
-            parser.parse::<kw::nullref>()?;
-            Ok(ValType::Nullref)
+            Ok(ValType::Ref(RefType::Extern))
         } else if l.peek::<ast::LParen>() {
             parser.parens(|p| {
                 let mut l = parser.lookahead1();
                 if l.peek::<kw::r#ref>() {
                     p.parse::<kw::r#ref>()?;
-
-                    let mut l = parser.lookahead1();
-                    if l.peek::<kw::func>() {
-                        parser.parse::<kw::func>()?;
-                        Ok(ValType::Funcref)
-                    } else if l.peek::<kw::any>() {
-                        parser.parse::<kw::any>()?;
-                        Ok(ValType::Anyref)
-                    } else if l.peek::<kw::null>() {
-                        parser.parse::<kw::null>()?;
-                        Ok(ValType::Nullref)
-                    } else if l.peek::<kw::exn>() {
-                        parser.parse::<kw::exn>()?;
-                        Ok(ValType::Exnref)
-                    } else if l.peek::<kw::eq>() {
-                        parser.parse::<kw::eq>()?;
-                        Ok(ValType::Eqref)
-                    } else if l.peek::<kw::i31>() {
-                        parser.parse::<kw::i31>()?;
-                        Ok(ValType::I31ref)
-                    } else if l.peek::<kw::opt>() {
-                        parser.parse::<kw::opt>()?;
-                        Ok(ValType::Optref(parser.parse()?))
-                    } else if l.peek::<ast::Index>() {
-                        Ok(ValType::Ref(parser.parse()?))
-                    } else {
-                        Err(l.error())
-                    }
+                    Ok(ValType::Ref(p.parse()?))
                 } else if l.peek::<kw::optref>() {
                     p.parse::<kw::optref>()?;
-                    Ok(ValType::Optref(parser.parse()?))
+                    Ok(ValType::Ref(RefType::OptType(parser.parse()?)))
                 } else if l.peek::<kw::rtt>() {
                     p.parse::<kw::rtt>()?;
                     Ok(ValType::Rtt(parser.parse()?))
@@ -104,13 +72,80 @@ impl<'a> Parse<'a> for ValType<'a> {
             })
         } else if l.peek::<kw::exnref>() {
             parser.parse::<kw::exnref>()?;
-            Ok(ValType::Exnref)
+            Ok(ValType::Ref(RefType::Exn))
         } else if l.peek::<kw::eqref>() {
             parser.parse::<kw::eqref>()?;
-            Ok(ValType::Eqref)
+            Ok(ValType::Ref(RefType::Eq))
         } else if l.peek::<kw::i31ref>() {
             parser.parse::<kw::i31ref>()?;
-            Ok(ValType::I31ref)
+            Ok(ValType::Ref(RefType::I31))
+        } else {
+            Err(l.error())
+        }
+    }
+}
+
+/// The reference value types for a wasm module.
+#[allow(missing_docs)]
+#[derive(Debug, PartialEq, Eq, Hash, Copy, Clone)]
+pub enum RefType<'a> {
+    /// An untyped function reference: funcref. This is part of the reference
+    /// types proposal.
+    Func,
+    /// A reference to any host value: externref. This was originally known as
+    /// anyref when it was the supertype of all reference value types. This is
+    /// part of the reference types proposal.
+    Extern,
+    /// A reference to an exception: exnref. This is part of the exception
+    /// handling proposal.
+    Exn,
+    /// A reference that has an identity that can be compared: eqref. This is
+    /// part of the GC proposal.
+    Eq,
+    /// An unboxed 31-bit integer: i31ref. This may be going away if there is no common
+    /// supertype of all reference types. Part of the GC proposal.
+    I31,
+    /// A reference to a function, struct, or array: ref T. This is part of the
+    /// GC proposal.
+    Type(ast::Index<'a>),
+    /// A nullable reference to a function, struct, or array: optref T. This is
+    /// part of the GC proposal.
+    OptType(ast::Index<'a>),
+}
+
+impl<'a> From<TableElemType> for RefType<'a> {
+    fn from(elem: TableElemType) -> Self {
+        match elem {
+            TableElemType::Funcref => RefType::Func,
+            TableElemType::Externref => RefType::Extern,
+            TableElemType::Exnref => RefType::Exn,
+        }
+    }
+}
+
+impl<'a> Parse<'a> for RefType<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        let mut l = parser.lookahead1();
+        if l.peek::<kw::func>() {
+            parser.parse::<kw::func>()?;
+            Ok(RefType::Func)
+        } else if l.peek::<kw::r#extern>() {
+            parser.parse::<kw::r#extern>()?;
+            Ok(RefType::Extern)
+        } else if l.peek::<kw::exn>() {
+            parser.parse::<kw::exn>()?;
+            Ok(RefType::Exn)
+        } else if l.peek::<kw::eq>() {
+            parser.parse::<kw::eq>()?;
+            Ok(RefType::Eq)
+        } else if l.peek::<kw::i31>() {
+            parser.parse::<kw::i31>()?;
+            Ok(RefType::I31)
+        } else if l.peek::<kw::opt>() {
+            parser.parse::<kw::opt>()?;
+            Ok(RefType::OptType(parser.parse()?))
+        } else if l.peek::<ast::Index>() {
+            Ok(RefType::Type(parser.parse()?))
         } else {
             Err(l.error())
         }
@@ -146,16 +181,12 @@ impl<'a> Parse<'a> for GlobalType<'a> {
 }
 
 /// List of different kinds of table types we can have.
-///
-/// Currently there's only one, a `funcref`.
 #[derive(Copy, Clone, Debug)]
 pub enum TableElemType {
     /// An element for a table that is a list of functions.
     Funcref,
-    /// An element for a table that is a list of `anyref` values.
-    Anyref,
-    /// An element for a table that is a list of `nullref` values.
-    Nullref,
+    /// An element for a table that is a list of `externref` values.
+    Externref,
     /// An element for a table that is a list of `exnref` values.
     Exnref,
 }
@@ -172,11 +203,13 @@ impl<'a> Parse<'a> for TableElemType {
             parser.parse::<kw::funcref>()?;
             Ok(TableElemType::Funcref)
         } else if l.peek::<kw::anyref>() {
+            // Parse `anyref` as an alias of `externref` until all tests are
+            // ported to use the new name
             parser.parse::<kw::anyref>()?;
-            Ok(TableElemType::Anyref)
-        } else if l.peek::<kw::nullref>() {
-            parser.parse::<kw::nullref>()?;
-            Ok(TableElemType::Nullref)
+            Ok(TableElemType::Externref)
+        } else if l.peek::<kw::externref>() {
+            parser.parse::<kw::externref>()?;
+            Ok(TableElemType::Externref)
         } else if l.peek::<kw::exnref>() {
             parser.parse::<kw::exnref>()?;
             Ok(TableElemType::Exnref)
@@ -190,7 +223,7 @@ impl Peek for TableElemType {
     fn peek(cursor: Cursor<'_>) -> bool {
         kw::funcref::peek(cursor)
             || kw::anyref::peek(cursor)
-            || kw::nullref::peek(cursor)
+            || kw::externref::peek(cursor)
             || /* legacy */ kw::anyfunc::peek(cursor)
             || kw::exnref::peek(cursor)
     }
diff --git a/third_party/rust/wast/src/binary.rs b/third_party/rust/wast/src/binary.rs
index e68890fd6e..96add442e7 100644
--- a/third_party/rust/wast/src/binary.rs
+++ b/third_party/rust/wast/src/binary.rs
@@ -250,24 +250,33 @@ impl<'a> Encode for ValType<'a> {
             ValType::V128 => e.push(0x7b),
             ValType::I8 => e.push(0x7a),
             ValType::I16 => e.push(0x79),
-            ValType::Funcref => e.push(0x70),
-            ValType::Anyref => e.push(0x6f),
-            ValType::Nullref => e.push(0x6e),
-            ValType::Ref(index) => {
-                e.push(0x6d);
-                index.encode(e);
+            ValType::Ref(ty) => {
+                ty.encode(e);
             }
-            ValType::Optref(index) => {
-                e.push(0x6c);
-                index.encode(e);
-            }
-            ValType::Eqref => e.push(0x6b),
-            ValType::I31ref => e.push(0x6a),
             ValType::Rtt(index) => {
                 e.push(0x69);
                 index.encode(e);
             }
-            ValType::Exnref => e.push(0x68),
+        }
+    }
+}
+
+impl<'a> Encode for RefType<'a> {
+    fn encode(&self, e: &mut Vec<u8>) {
+        match self {
+            RefType::Func => e.push(0x70),
+            RefType::Extern => e.push(0x6f),
+            RefType::Eq => e.push(0x6b),
+            RefType::I31 => e.push(0x6a),
+            RefType::Exn => e.push(0x68),
+            RefType::Type(index) => {
+                e.push(0x6d);
+                index.encode(e);
+            }
+            RefType::OptType(index) => {
+                e.push(0x6c);
+                index.encode(e);
+            }
         }
     }
 }
@@ -329,10 +338,9 @@ impl Encode for TableType {
 impl Encode for TableElemType {
     fn encode(&self, e: &mut Vec<u8>) {
         match self {
-            TableElemType::Funcref => ValType::Funcref.encode(e),
-            TableElemType::Anyref => ValType::Anyref.encode(e),
-            TableElemType::Nullref => ValType::Nullref.encode(e),
-            TableElemType::Exnref => ValType::Exnref.encode(e),
+            TableElemType::Funcref => RefType::Func.encode(e),
+            TableElemType::Externref => RefType::Extern.encode(e),
+            TableElemType::Exnref => RefType::Exn.encode(e),
         }
     }
 }
@@ -517,7 +525,7 @@ impl Encode for ElemPayload<'_> {
     fn encode(&self, e: &mut Vec<u8>) {
         match self {
             ElemPayload::Indices(v) => v.encode(e),
-            ElemPayload::Exprs { exprs, .. } => {
+            ElemPayload::Exprs { exprs, ty } => {
                 exprs.len().encode(e);
                 for idx in exprs {
                     match idx {
@@ -525,7 +533,7 @@ impl Encode for ElemPayload<'_> {
                             Instruction::RefFunc(*idx).encode(e);
                         }
                         None => {
-                            Instruction::RefNull.encode(e);
+                            Instruction::RefNull((*ty).into()).encode(e);
                         }
                     }
                     Instruction::End(None).encode(e);
diff --git a/third_party/rust/wast/src/resolve/names.rs b/third_party/rust/wast/src/resolve/names.rs
index 71d6630e2c..19acef7cc3 100644
--- a/third_party/rust/wast/src/resolve/names.rs
+++ b/third_party/rust/wast/src/resolve/names.rs
@@ -209,7 +209,20 @@ impl<'a> Resolver<'a> {
 
     fn resolve_valtype(&self, ty: &mut ValType<'a>) -> Result<(), Error> {
         match ty {
-            ValType::Ref(i) | ValType::Optref(i) | ValType::Rtt(i) => {
+            ValType::Ref(ty) => self.resolve_reftype(ty)?,
+            ValType::Rtt(i) => {
+                self.ns(Ns::Type)
+                    .resolve(i)
+                    .map_err(|id| self.resolve_error(id, "type"))?;
+            }
+            _ => {}
+        }
+        Ok(())
+    }
+
+    fn resolve_reftype(&self, ty: &mut RefType<'a>) -> Result<(), Error> {
+        match ty {
+            RefType::Type(i) | RefType::OptType(i) => {
                 self.ns(Ns::Type)
                     .resolve(i)
                     .map_err(|id| self.resolve_error(id, "type"))?;
@@ -514,7 +527,7 @@ impl<'a, 'b> ExprResolver<'a, 'b> {
                 ));
             }
 
-            Br(i) | BrIf(i) | BrOnCast(i) => self.resolve_label(i),
+            Br(i) | BrIf(i) | BrOnCast(i) | BrOnNull(i) => self.resolve_label(i),
 
             BrTable(i) => {
                 for label in i.labels.iter_mut() {
@@ -548,6 +561,8 @@ impl<'a, 'b> ExprResolver<'a, 'b> {
                 self.resolver.resolve_valtype(&mut s.to)
             }
 
+            RefNull(ty) | RefIsNull(ty) => self.resolver.resolve_reftype(ty),
+
             _ => Ok(()),
         }
     }
diff --git a/third_party/rust/wat/.cargo-checksum.json b/third_party/rust/wat/.cargo-checksum.json
index 6855729d4b..251c465c36 100644
--- a/third_party/rust/wat/.cargo-checksum.json
+++ b/third_party/rust/wat/.cargo-checksum.json
@@ -1 +1 @@
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\ No newline at end of file
+{"files":{"CODE_OF_CONDUCT.md":"a13aaaf393818bd91207c618724d3fb74944ca5161201822a84af951bcf655ef","Cargo.lock":"a90f917a3245a75bf71fd42be453f690d6bb81d12826a45475d4f34b5e26f03a","Cargo.toml":"5c80fef0f05012288e5db447dc31208c89ac6a098a8cb3cffa635f3a92027a94","LICENSE":"268872b9816f90fd8e85db5a28d33f8150ebb8dd016653fb39ef1f94f2686bc5","ORG_CODE_OF_CONDUCT.md":"59c4c4435538496193cd73e89b2cd971d1011dba573158cf108abe6af6603e6b","README.md":"142745665518b56481bc91d609db9f055526b78bd88af85a969910b2089a67ab","SECURITY.md":"4d75afb09dd28eb5982e3a1f768ee398d90204669ceef3240a16b31dcf04148a","examples/wat2wasm.rs":"732f98472727c7a76bf08e0a9984032925b556cc357fbcd24007e00b9b80fb13","src/lib.rs":"03652351228b7f7a520f4e7f1e689fa34a37b8e5e0fc8367a167cc893cdbc449","tests/annotations.rs":"e7532c26a8671391576da77b13fb47d756a785a66945b1bc9b5621d5b6d7f2fc","tests/comments.rs":"0513f64a2094dfa422ce30b0e6ff2d266fd240be54be702120558ff62fd9e703","tests/parse-fail.rs":"0f1d5dffd1e6145105571222096703c89c4f4a46e25c848faa730f731155ea1c","tests/parse-fail/bad-index.wat":"d21489daeec3a35327dcc9e2ba2d0acdd05f4aeaff2272cca608fda4d2338497","tests/parse-fail/bad-index.wat.err":"b66851e048a20240c3dc4c2a1a991436daf688a62fa94ff8f63a908fcaee8a9a","tests/parse-fail/bad-name.wat":"e5ff5d410007779a0de6609ea4cc693f0e603d36a106b8f5098c1980dd9f8124","tests/parse-fail/bad-name.wat.err":"fb5638476c1b85d9d1919e3dbcb0f16f82d088a4a22d4a0c186d7b8ba6e1902b","tests/parse-fail/bad-name2.wat":"5a6a4d0c19e5f2e48d7cebf361aca9b9000b7ef0c652997b5bd0ffaadbd2ca8a","tests/parse-fail/bad-name2.wat.err":"129707cce45f1e3cfb3e2ca5c702182e16ca5eeb2dbb2edd0710b004a8e194a5","tests/parse-fail/bad-name3.wat":"c19133d738cc84e9174301f27d4050c216bda81c7e9918d03ac792b088f24a05","tests/parse-fail/bad-name3.wat.err":"84ea63d40a619a0782ec6e94fce63921188ab87b1c3875eacae0a371144ed83a","tests/parse-fail/block1.wat":"91e74b5c3b43be692e7a6ae74fbfa674c4b6197299eb61338c4eccf282b18f17","tests/parse-fail/block1.wat.err":"40a083ae496b41dee7002cc6a664c5db0c5e4d904ae03b815773a769c4493fca","tests/parse-fail/block2.wat":"a8c07b4c09d51f10a8ffdf19806586022552398701cd90eb6d09816d45df06e5","tests/parse-fail/block2.wat.err":"33c842ec5dd0f2fdd3a9ce8187dd98b45ceee48c12810802af809d05b9cd25e9","tests/parse-fail/block3.wat":"29739abfbabd7c55f00ddfbbb9ebd818b4a114ef2336d50514f0842f7e075905","tests/parse-fail/block3.wat.err":"fc667ae2e71a260f62a3c7393bc97272e7c0ff38b17594f4370847b8a5019060","tests/parse-fail/inline1.wat":"4e9767d67207aace2ac5e6f63a30e7510e4aa245ba35420539509e2254470272","tests/parse-fail/inline1.wat.err":"0143017a9825e518baa6009bae2c8d63520051dedd3437705bbe36b038a57f41","tests/parse-fail/string1.wat":"620d46d585ce94b382b5fde628c1399f3e562014b7a44af46e92f7bd045ca86e","tests/parse-fail/string1.wat.err":"fc53f3a1c4a65d8f25e5af51dec7699f45cecba114ca9c7871781bc70f664320","tests/parse-fail/string10.wat":"f7409dd45e153a1b11cb23e38f4ed87da12bedde38f8f0ccfe91037b0a4d97bd","tests/parse-fail/string10.wat.err":"ce677db5e37e0ed81ca357ed6b5edb21d85c27303ee194855bea7a88457efb6a","tests/parse-fail/string11.wat":"f6e0400b8c6a2014efa1ac676c567e140d8f86b5f4d5129773e6d67af537b615","tests/parse-fail/string11.wat.err":"4c6a550d29eda38a4e1bf7a589596f11655dc779479d7b8d466cfc53f815a742","tests/parse-fail/string12.wat":"23e30070eef22271651cce096a801fc4f79f3c37343c88bb8d2fc99b32d3b8b9","tests/parse-fail/string12.wat.err":"6e9a2ec052068bb234da56404087c03a66705846d82c095605530243fdce38f3","tests/parse-fail/string13.wat":"81a305b981159ee10e140749ea3220c9edaaff53605e63c21995de47382b5faf","tests/parse-fail/string13.wat.err":"ac0c51a1964abc1a1104858d16c124a4e5495705bc3adc0ab123cd0ba8ab9ee9","tests/parse-fail/string14.wat":"c45c2cc9f7afbfbd4be8e513106d22f7e5e817091448576c6bdf0701b81d95dd","tests/parse-fail/string14.wat.err":"cc3f6b0c093d878373ab29726b8ac0620b982a4842ec521b8661e864eed1ef05","tests/parse-fail/string15.wat":"b5e0d5ade40de53b2d767a132e28376bb8c7a6f6238c4d8c248ae717c41d7f1f","tests/parse-fail/string15.wat.err":"6549a0575bc228c2e12ec197e40bb5fdc665325a0242ca8a62e7a8dc5de6aee8","tests/parse-fail/string16.wat":"38c3688cee80a9d089d239aa06eb1d27c5364ad2bd270aca57d05997c20aa682","tests/parse-fail/string16.wat.err":"4274b3bbe4df4cf0373619b1fcd082d0c802990817d2aca26ed885168c80e489","tests/parse-fail/string2.wat":"1172964aed31537b8c466d1f045f3e756926e7b221f80b2aff4a9a6721ea0beb","tests/parse-fail/string2.wat.err":"4618d3b20a78a077337eb5d6cae14ac39d9853762f011fbd23cff8921618dbde","tests/parse-fail/string3.wat":"07e0fbcd6270c1db100917c151ee4ac3f935e4ee1b27bce3c453b22b4b74f4d6","tests/parse-fail/string3.wat.err":"84833a2f45216097a871ae88beb515ebeb8dab5d7c007ec98f1fcf1b20f7558d","tests/parse-fail/string4.wat":"c970da2051b0613bdd1de4664f10424e14f2ebabe604175d4fb9b763b37af577","tests/parse-fail/string4.wat.err":"406706594d305c560fabd66417ad4fc276939990b5e701bd9d13fc223d207219","tests/parse-fail/string5.wat":"386cf314bb05acdaaabdf4da1caf140167271a26bd08bf34c3a7427d4bc4431f","tests/parse-fail/string5.wat.err":"1e56b44a23a37b2b2ad05aa9dd7e1e18191b5cc22151f93bbcf9d618779a57bd","tests/parse-fail/string6.wat":"8f1fe2825ff96f2acee9130a7721f86fcc93c221baa9411bf1fb6f0870d38ccb","tests/parse-fail/string6.wat.err":"d55dfd84d94e893f167ae73b7a080aefb2bfb05cc8a1ec201c4d3066fb8549b4","tests/parse-fail/string7.wat":"b12f8c75313d7f834489d3c353422f90bc945b37139586446eda82e334a97cde","tests/parse-fail/string7.wat.err":"4cee0ca61992c249dd0faaf2529a073cf8deeb36111a3f69b43695e5682560a2","tests/parse-fail/string8.wat":"4c2e0e1f883bb4e8cba9313497ed792130e5848e62bde7716102788d7467be10","tests/parse-fail/string8.wat.err":"840c6def7c60dd7c2b7261549cab435ba78c9b3a937adf6d5d9595ff8af01c91","tests/parse-fail/string9.wat":"2b7670caed2b0688d535de6e4e416f35fa717cfbe096a6cc764a669085c8f52f","tests/parse-fail/string9.wat.err":"37b5a9c3af9631500f31f9e5e3efa821b8d96063c57d60fd01df6be6a5c323e1","tests/parse-fail/unbalanced.wat":"f664fbef53a0308f864ba496d38044eb90482636e32586512939d4930729f3fe","tests/parse-fail/unbalanced.wat.err":"aba579f7b836856e69afe05da8328aabe0643d94e369898e686aa7bb0b07e9c9","tests/recursive.rs":"ad8a2b07bf955121a7c9e326ed35f9b2bc56b440c8cc0bbde24d423a79945c1a","tests/regression/atomics.wat":"a108dfdf4e9bb2354d1e7fedcd5400895b83d61e2a490822126b052f817bb181","tests/regression/blockty.wat":"0065feef652cb61ac373872087e47f814a41123e186c330e4e528bd826aac65c","tests/regression/comments.wat":"4f53ed7a57032c2a46c3500fa67f67ee99fe11356ea4da7cbd5fb5f0622a87b7","tests/regression/dummy.wat":"3584af5e1ab0b1da09b5326237be4b178de0bb388d6093efd94e6aec56c20a74","tests/regression/duplicate.wast":"4165aa6a0b63f8da9711d8c87b0050bec7782c1a4d2458be650da62d97d95af6","tests/regression/empty.wast":"f90a763ae591c7a36e6c196f3590f256893131c4bb01dd2d72be71955e0101de","tests/regression/exnref.wat":"fb9db7f161520765ffba42e1d46ba82b02c1e4d3d806ab6604c121b56fd55b4c","tests/regression/float1.wat":"ac6d63cafac2fb07350b12cf9f51c103befd45bcad533fe219a243cb85bdcc33","tests/regression/fuzz1.wat":"040b9ab7057921fbd10f92ce19043127308a91d68a8bb36ab2693eb63e416127","tests/regression/gc-ref-global-import.wat":"119d5ce3b368c87fd60285afd05ecee0ef0708f431680ab27d07e4816facf9ca","tests/regression/gc-ref.wat":"e43018a372af39ee8fdab2b138521f99d9d2e20e471ce65162a4675cb798625e","tests/regression/gc-struct.wat":"f35201997ad2b2c445879fab551c1639b65a25430494ca71ca9c9bde1c819dc2","tests/regression/invalid-ty.wat":"c39a6983fbb6bb4a1d1707c9090b21722a045971d413061be1c8303fe08822a2","tests/regression/invalid-ty2.wat":"9ad7058686938288cc6eee992d1dc7297ef6bcfd5df4114b85e9a2538e80cf05","tests/regression/table-copy.wat":"21499c333dff7133939891ebd0a4c80cc9600e269f3e46b9045b653c95a650a7","tests/regression/table-init.wat":"5f63eba7e9459a58a7a2af48121d137747eefe22457bafa00c87c36772597a2d","tests/regression/table-opt-idx.wat":"de12f59cdb7e843bb08b6be3a5f8649d59d68eef9389650580ef607ebe710ef8","tests/wabt.rs":"0f120c59d987b119cbaf05f4532590a8b15c1d2f607c4b37f8579febf70e6e9f"},"package":"a02463c6661a0d5a089d795e2e49ab34594b41265e8bd5ff3e0810e2a1f84222"}
\ No newline at end of file
diff --git a/third_party/rust/wat/Cargo.lock b/third_party/rust/wat/Cargo.lock
index 6079708455..96c58220ce 100644
--- a/third_party/rust/wat/Cargo.lock
+++ b/third_party/rust/wat/Cargo.lock
@@ -2,24 +2,15 @@
 # It is not intended for manual editing.
 [[package]]
 name = "anyhow"
-version = "1.0.26"
+version = "1.0.28"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7825f6833612eb2414095684fcf6c635becf3ce97fe48cf6421321e93bfbd53c"
+checksum = "d9a60d744a80c30fcb657dfe2c1b22bcb3e814c1a1e3674f32bf5820b570fbff"
 
 [[package]]
 name = "autocfg"
-version = "0.1.7"
+version = "1.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1d49d90015b3c36167a20fe2810c5cd875ad504b39cff3d4eae7977e6b7c1cb2"
-
-[[package]]
-name = "c2-chacha"
-version = "0.2.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "214238caa1bf3a496ec3392968969cab8549f96ff30652c9e56885329315f6bb"
-dependencies = [
- "ppv-lite86",
-]
+checksum = "f8aac770f1885fd7e387acedd76065302551364496e46b3dd00860b2f8359b9d"
 
 [[package]]
 name = "cfg-if"
@@ -29,24 +20,26 @@ checksum = "4785bdd1c96b2a846b2bd7cc02e86b6b3dbf14e7e53446c4f54c92a361040822"
 
 [[package]]
 name = "crossbeam-deque"
-version = "0.7.2"
+version = "0.7.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c3aa945d63861bfe624b55d153a39684da1e8c0bc8fba932f7ee3a3c16cea3ca"
+checksum = "9f02af974daeee82218205558e51ec8768b48cf524bd01d550abe5573a608285"
 dependencies = [
  "crossbeam-epoch",
  "crossbeam-utils",
+ "maybe-uninit",
 ]
 
 [[package]]
 name = "crossbeam-epoch"
-version = "0.8.0"
+version = "0.8.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5064ebdbf05ce3cb95e45c8b086f72263f4166b29b97f6baff7ef7fe047b55ac"
+checksum = "058ed274caafc1f60c4997b5fc07bf7dc7cca454af7c6e81edffe5f33f70dace"
 dependencies = [
  "autocfg",
  "cfg-if",
  "crossbeam-utils",
  "lazy_static",
+ "maybe-uninit",
  "memoffset",
  "scopeguard",
 ]
@@ -63,9 +56,9 @@ dependencies = [
 
 [[package]]
 name = "crossbeam-utils"
-version = "0.7.0"
+version = "0.7.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ce446db02cdc3165b94ae73111e570793400d0794e46125cc4056c81cbb039f4"
+checksum = "c3c7c73a2d1e9fc0886a08b93e98eb643461230d5f1925e4036204d5f2e261a8"
 dependencies = [
  "autocfg",
  "cfg-if",
@@ -100,9 +93,9 @@ dependencies = [
 
 [[package]]
 name = "hermit-abi"
-version = "0.1.7"
+version = "0.1.12"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e2c55f143919fbc0bc77e427fe2d74cf23786d7c1875666f2fde3ac3c659bb67"
+checksum = "61565ff7aaace3525556587bd2dc31d4a07071957be715e63ce7b1eccf51a8f4"
 dependencies = [
  "libc",
 ]
@@ -127,24 +120,30 @@ checksum = "3576a87f2ba00f6f106fdfcd16db1d698d648a26ad8e0573cad8537c3c362d2a"
 
 [[package]]
 name = "libc"
-version = "0.2.67"
+version = "0.2.69"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "eb147597cdf94ed43ab7a9038716637d2d1bf2bc571da995d0028dec06bd3018"
+checksum = "99e85c08494b21a9054e7fe1374a732aeadaff3980b6990b94bfd3a70f690005"
+
+[[package]]
+name = "maybe-uninit"
+version = "2.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "60302e4db3a61da70c0cb7991976248362f30319e88850c487b9b95bbf059e00"
 
 [[package]]
 name = "memoffset"
-version = "0.5.3"
+version = "0.5.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "75189eb85871ea5c2e2c15abbdd541185f63b408415e5051f5cac122d8c774b9"
+checksum = "b4fc2c02a7e374099d4ee95a193111f72d2110197fe200272371758f6c3643d8"
 dependencies = [
- "rustc_version",
+ "autocfg",
 ]
 
 [[package]]
 name = "num_cpus"
-version = "1.12.0"
+version = "1.13.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "46203554f085ff89c235cd12f7075f3233af9b11ed7c9e16dfe2560d03313ce6"
+checksum = "05499f3756671c15885fee9034446956fff3f243d6077b91e5767df161f766b3"
 dependencies = [
  "hermit-abi",
  "libc",
@@ -171,11 +170,11 @@ dependencies = [
 
 [[package]]
 name = "rand_chacha"
-version = "0.2.1"
+version = "0.2.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "03a2a90da8c7523f554344f921aa97283eadf6ac484a6d2a7d0212fa7f8d6853"
+checksum = "f4c8ed856279c9737206bf725bf36935d8666ead7aa69b52be55af369d193402"
 dependencies = [
- "c2-chacha",
+ "ppv-lite86",
  "rand_core",
 ]
 
@@ -236,20 +235,11 @@ dependencies = [
  "winapi",
 ]
 
-[[package]]
-name = "rustc_version"
-version = "0.2.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "138e3e0acb6c9fb258b19b67cb8abd63c00679d2851805ea151465464fe9030a"
-dependencies = [
- "semver",
-]
-
 [[package]]
 name = "ryu"
-version = "1.0.2"
+version = "1.0.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "bfa8506c1de11c9c4e4c38863ccbe02a305c8188e85a05a784c9e11e1c3910c8"
+checksum = "ed3d612bc64430efeb3f7ee6ef26d590dce0c43249217bddc62112540c7941e1"
 
 [[package]]
 name = "scopeguard"
@@ -257,32 +247,17 @@ version = "1.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d29ab0c6d3fc0ee92fe66e2d99f700eab17a8d57d1c1d3b748380fb20baa78cd"
 
-[[package]]
-name = "semver"
-version = "0.9.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1d7eb9ef2c18661902cc47e535f9bc51b78acd254da71d375c2f6720d9a40403"
-dependencies = [
- "semver-parser",
-]
-
-[[package]]
-name = "semver-parser"
-version = "0.7.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "388a1df253eca08550bef6c72392cfe7c30914bf41df5269b68cbd6ff8f570a3"
-
 [[package]]
 name = "serde"
-version = "1.0.104"
+version = "1.0.106"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "414115f25f818d7dfccec8ee535d76949ae78584fc4f79a6f45a904bf8ab4449"
+checksum = "36df6ac6412072f67cf767ebbde4133a5b2e88e76dc6187fa7104cd16f783399"
 
 [[package]]
 name = "serde_json"
-version = "1.0.48"
+version = "1.0.52"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9371ade75d4c2d6cb154141b9752cf3781ec9c05e0e5cf35060e1e70ee7b9c25"
+checksum = "a7894c8ed05b7a3a279aeb79025fdec1d3158080b75b98a08faf2806bb799edd"
 dependencies = [
  "itoa",
  "ryu",
@@ -317,22 +292,22 @@ checksum = "cccddf32554fecc6acb585f82a32a72e28b48f8c4c1883ddfeeeaa96f7d8e519"
 
 [[package]]
 name = "wasmparser"
-version = "0.51.2"
+version = "0.52.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a40d24f114a3f24b459ec292019220cff6388673b4a2c0a11483665b599ef15c"
+checksum = "7daff424bb0ec17d7dfb3f36e6d13a3882b2a5bebf997769ac853d5f950d6513"
 
 [[package]]
 name = "wast"
-version = "13.0.0"
+version = "16.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5b20abd8b4a26f7e0d4dd5e357e90a3d555ec190e94472c9b2b27c5b9777f9ae"
+checksum = "8564a0c8f4d468d71c2b263dd1f675fa2cac6e7331ff8379cbb88cb79fcef8d1"
 dependencies = [
  "leb128",
 ]
 
 [[package]]
 name = "wat"
-version = "1.0.14"
+version = "1.0.17"
 dependencies = [
  "anyhow",
  "getopts",
diff --git a/third_party/rust/wat/Cargo.toml b/third_party/rust/wat/Cargo.toml
index 6cf700e67a..022723084b 100644
--- a/third_party/rust/wat/Cargo.toml
+++ b/third_party/rust/wat/Cargo.toml
@@ -13,7 +13,7 @@
 [package]
 edition = "2018"
 name = "wat"
-version = "1.0.14"
+version = "1.0.17"
 authors = ["Alex Crichton <alex@alexcrichton.com>"]
 exclude = ["tests/wabt", "tests/testsuite"]
 description = "Rust parser for the WebAssembly Text format, WAT\n"
@@ -35,7 +35,7 @@ harness = false
 name = "parse-fail"
 harness = false
 [dependencies.wast]
-version = "13.0.0"
+version = "16.0.0"
 [dev-dependencies.anyhow]
 version = "1.0"
 
@@ -52,4 +52,4 @@ version = "1.0"
 version = "3.1"
 
 [dev-dependencies.wasmparser]
-version = "0.51"
+version = "0.52"
diff --git a/third_party/rust/wat/tests/parse-fail/bad-index.wat b/third_party/rust/wat/tests/parse-fail/bad-index.wat
new file mode 100644
index 0000000000..34262539a5
--- /dev/null
+++ b/third_party/rust/wat/tests/parse-fail/bad-index.wat
@@ -0,0 +1 @@
+(func br_on_null $s)
diff --git a/third_party/rust/wat/tests/parse-fail/bad-index.wat.err b/third_party/rust/wat/tests/parse-fail/bad-index.wat.err
new file mode 100644
index 0000000000..717d46017b
--- /dev/null
+++ b/third_party/rust/wat/tests/parse-fail/bad-index.wat.err
@@ -0,0 +1,5 @@
+failed to find label named `$s`
+     --> tests/parse-fail/bad-index.wat:1:18
+      |
+    1 | (func br_on_null $s)
+      |                  ^
diff --git a/third_party/rust/wat/tests/regression/gc-struct.wat b/third_party/rust/wat/tests/regression/gc-struct.wat
index 0c3bf433dc..9aec0cce29 100644
--- a/third_party/rust/wat/tests/regression/gc-struct.wat
+++ b/third_party/rust/wat/tests/regression/gc-struct.wat
@@ -21,6 +21,5 @@
   (func
     struct.narrow i32 f32
     struct.narrow anyref funcref
-    struct.narrow anyref nullref
   )
 )
diff --git a/third_party/rust/wat/tests/wabt.rs b/third_party/rust/wat/tests/wabt.rs
index 7866605206..2de20fd5bb 100644
--- a/third_party/rust/wat/tests/wabt.rs
+++ b/third_party/rust/wat/tests/wabt.rs
@@ -245,6 +245,7 @@ fn error_matches(error: &str, message: &str) -> bool {
         || message == "unclosed annotation"
         || message == "malformed annotation id"
         || message == "alignment must be a power of two"
+        || message == "i32 constant out of range"
     {
         return error.contains("expected ")
             || error.contains("constant out of range")
@@ -445,6 +446,10 @@ struct Wast2Json {
 }
 
 fn wast2json(test: &Path) -> Option<Wast2Json> {
+    // Right now wabt infinite loops on this test.
+    if test.ends_with("testsuite/proposals/annotations/annotations.wast") {
+        return None;
+    }
     let td = tempfile::TempDir::new().unwrap();
     let result = Command::new("wast2json")
         .arg(test)
@@ -504,5 +509,23 @@ fn skip_test(test: &Path, contents: &str) -> bool {
         return true;
     }
 
+    // Waiting for wabt to remove subtyping from reference-types.
+    if test
+        .iter()
+        .any(|x| x == "bulk-memory-operations" || x == "reference-types")
+        || test.ends_with("reference-types.txt")
+        || test.ends_with("all-features.txt")
+        || test.ends_with("all-features.txt")
+        || test.ends_with("bulk-memory-named.txt")
+        || test.ends_with("reference-types-named.txt")
+        || test.ends_with("table-grow.txt")
+        || test.ends_with("result-exnref.txt")
+        || test.ends_with("global-exnref.txt")
+        || test.ends_with("global.txt")
+        || test.ends_with("bulk-memory.txt")
+    {
+        return true;
+    }
+
     false
 }
diff --git a/third_party/rust/weedle/.cargo-checksum.json b/third_party/rust/weedle/.cargo-checksum.json
deleted file mode 100644
index 3fadecee00..0000000000
--- a/third_party/rust/weedle/.cargo-checksum.json
+++ /dev/null
@@ -1 +0,0 @@
-{"files":{"Cargo.toml":"84dc605d368f68a3e25b2e240552ce6e2a8731e80f73cfd4cb0b931528b473a7","LICENSE.md":"47cdc00faacda4d0ac0dabfcef03ab6f4bef6a02f80cb3fd0482047f00f9a16d","README.md":"e4363ea12b63bb6d3e461396f6fd46fe4cbf9a8635258499f4d551dadfc06655","src/argument.rs":"be162d59a9f1ef7d9d51d0f3492946f0dd263202af8355eeaee14ce4181775fc","src/attribute.rs":"b3577059be9c1262d3360b4b4cf4cc6cb052251e5b9d64906fb40fc5e925da69","src/common.rs":"7ac264f83ff596914af32fb08947cc500a75df57e43d9b2fce93163e5a20a738","src/dictionary.rs":"be209d70b0db33acf753ca63998a63dd37a9d4b193583a1490782781360c2d01","src/interface.rs":"4e1f37079dec75633b26289b82bda0d3b4a1479a4aede74c01e20fe6c2d93496","src/lib.rs":"762c35dc6ef77b6b1c871bd0391d09203a479937e4688a029a17c8d8a5f9e8ba","src/literal.rs":"dd58d410e2329633e2b2151157b29671ad5f78c8be0bec5c81be083168311f94","src/macros.rs":"aa95fd957d5175fb2779faec5d40b717fb5efd581f0f13ef7ba3510f37092da3","src/mixin.rs":"d65ff3a49615dabdf3f7845723f01ae730a83c8ef5bdd9a945d35149a9ef2858","src/namespace.rs":"fe6b406c2ab8bd904d0dff8a12321c77f4082ab364559e578e53ab415c8541fa","src/term.rs":"48ac583ae73d115afbedca6e7e9f32b316b7a308ba37cb9153eeac9773561028","src/types.rs":"3f81a1d820f0b6777f46c74366359953bf79465c3eb1ace4b3a383c22f4e1d88","src/whitespace.rs":"069df2ae0f37d621a8ef84b08408c090ff1ead8164e52caa8ea7d57838f04cac","tests/defs/dom.webidl":"93a70734538233a6b9db7578375b5a3d8783bcdcfc9970cc61cddcd03c832d6c","tests/defs/html.webidl":"4b2be1a0435b1fc26e60083006e2ecf7158611c190f95e5c4c8290510de22777","tests/defs/interface-constructor.webidl":"8b31240c838607e460086cb55a57a111605199f88f4291a83f7125c8c3c4fd1a","tests/defs/mediacapture-streams.webidl":"82615b15129e87aac56a0ca74bd763c5416732020a2b567dc4582835e0846144","tests/webidl.rs":"097683a01f3c058be3341d7d8b0af18964686059485941cbee22e63b94406c1f"},"package":"8a7d4f9feb723a800d8f7b74edc9fa44ff35cb0b2ec64886714362f423427f37"}
\ No newline at end of file
diff --git a/third_party/rust/weedle/Cargo.toml b/third_party/rust/weedle/Cargo.toml
deleted file mode 100644
index ea808e820a..0000000000
--- a/third_party/rust/weedle/Cargo.toml
+++ /dev/null
@@ -1,27 +0,0 @@
-# THIS FILE IS AUTOMATICALLY GENERATED BY CARGO
-#
-# When uploading crates to the registry Cargo will automatically
-# "normalize" Cargo.toml files for maximal compatibility
-# with all versions of Cargo and also rewrite `path` dependencies
-# to registry (e.g., crates.io) dependencies
-#
-# If you believe there's an error in this file please file an
-# issue against the rust-lang/cargo repository. If you're
-# editing this file be aware that the upstream Cargo.toml
-# will likely look very different (and much more reasonable)
-
-[package]
-edition = "2018"
-name = "weedle"
-version = "0.11.0"
-authors = ["Sharad Chand <sharad.d.chand@gmail.com>"]
-description = "A WebIDL Parser"
-homepage = "https://github.com/rustwasm/weedle"
-documentation = "https://docs.rs/weedle"
-readme = "./README.md"
-license = "MIT"
-repository = "https://github.com/rustwasm/weedle"
-[dependencies.nom]
-version = "5.0.0"
-features = ["std"]
-default-features = false
diff --git a/third_party/rust/weedle/LICENSE.md b/third_party/rust/weedle/LICENSE.md
deleted file mode 100644
index a364c10305..0000000000
--- a/third_party/rust/weedle/LICENSE.md
+++ /dev/null
@@ -1,15 +0,0 @@
-Copyright 2018-Present Sharad Chand
-
-Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated
-documentation files (the "Software"), to deal in the Software without restriction, including without limitation
-the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software,
-and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
-
-The above copyright notice and this permission notice shall be included in all copies or substantial portions
-of the Software.
-
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
-TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
-THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
-CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
-DEALINGS IN THE SOFTWARE.
\ No newline at end of file
diff --git a/third_party/rust/weedle/README.md b/third_party/rust/weedle/README.md
deleted file mode 100644
index acd0182f21..0000000000
--- a/third_party/rust/weedle/README.md
+++ /dev/null
@@ -1,49 +0,0 @@
-<div align="center">
-
-  <h1>Weedle</h1>
-
-  <strong>A Web IDL parser</strong>
-
-  <p>
-    <a href="https://travis-ci.org/rustwasm/weedle"><img src="https://img.shields.io/travis/rustwasm/weedle.svg?style=flat-square" alt="Build Status" /></a>
-    <a href="https://crates.io/crates/weedle"><img src="https://img.shields.io/crates/v/weedle.svg?style=flat-square" alt="Crates.io version" /></a>
-    <a href="https://crates.io/crates/weedle"><img src="https://img.shields.io/crates/d/weedle.svg?style=flat-square" alt="Download" /></a>
-    <a href="https://docs.rs/weedle"><img src="https://img.shields.io/badge/docs-latest-blue.svg?style=flat-square" alt="docs.rs docs" /></a>
-  </p>
-
-  <h3>
-    <a href="https://docs.rs/weedle">API Docs</a>
-    <span> | </span>
-    <a href="https://discordapp.com/channels/442252698964721669/443151097398296587">Chat</a>
-  </h3>
-
-  <sub>Built with 🦀🕸 by <a href="https://rustwasm.github.io/">The Rust and WebAssembly Working Group</a></sub>
-</div>
-
-## About
-
-Parses valid WebIDL definitions & produces a data structure starting from
-[`Definitions`](https://docs.rs/weedle/latest/weedle/type.Definitions.html).
-
-## Usage
-
-### `Cargo.toml`
-
-```toml
-[dependencies]
-weedle = "0.9.0"
-```
-
-### `src/main.rs`
-
-```rust
-fn main() {
-    let parsed = weedle::parse("
-        interface Window {
-            readonly attribute Storage sessionStorage;
-        };
-    ").unwrap();
-
-    println!("{:?}", parsed);
-}
-```
diff --git a/third_party/rust/weedle/src/argument.rs b/third_party/rust/weedle/src/argument.rs
deleted file mode 100644
index f2ac5a0133..0000000000
--- a/third_party/rust/weedle/src/argument.rs
+++ /dev/null
@@ -1,76 +0,0 @@
-use crate::attribute::ExtendedAttributeList;
-use crate::common::{Default, Identifier, Punctuated};
-use crate::types::{AttributedType, Type};
-
-/// Parses a list of argument. Ex: `double v1, double v2, double v3, optional double alpha`
-pub type ArgumentList<'a> = Punctuated<Argument<'a>, term!(,)>;
-
-ast_types! {
-    /// Parses an argument. Ex: `double v1|double... v1s`
-    enum Argument<'a> {
-        /// Parses `[attributes]? optional? attributedtype identifier ( = default )?`
-        ///
-        /// Note: `= default` is only allowed if `optional` is present
-        Single(struct SingleArgument<'a> {
-            attributes: Option<ExtendedAttributeList<'a>>,
-            optional: Option<term!(optional)>,
-            type_: AttributedType<'a>,
-            identifier: Identifier<'a>,
-            default: Option<Default<'a>> = map!(
-                cond!(optional.is_some(), weedle!(Option<Default<'a>>)),
-                |default| default.unwrap_or(None)
-            ),
-        }),
-        /// Parses `[attributes]? type... identifier`
-        Variadic(struct VariadicArgument<'a> {
-            attributes: Option<ExtendedAttributeList<'a>>,
-            type_: Type<'a>,
-            ellipsis: term!(...),
-            identifier: Identifier<'a>,
-        }),
-    }
-}
-
-#[cfg(test)]
-mod test {
-    use super::*;
-    use crate::literal::{DecLit, DefaultValue, IntegerLit};
-    use crate::Parse;
-
-    test!(should_parse_single_argument { "short a" =>
-        "";
-        SingleArgument;
-        attributes.is_none();
-        optional.is_none();
-        identifier.0 == "a";
-        default.is_none();
-    });
-
-    test!(should_parse_variadic_argument { "short... a" =>
-        "";
-        VariadicArgument;
-        attributes.is_none();
-        identifier.0 == "a";
-    });
-
-    test!(should_parse_optional_single_argument { "optional short a" =>
-        "";
-        SingleArgument;
-        attributes.is_none();
-        optional.is_some();
-        identifier.0 == "a";
-        default.is_none();
-    });
-
-    test!(should_parse_optional_single_argument_with_default { "optional short a = 5" =>
-        "";
-        SingleArgument;
-        attributes.is_none();
-        optional.is_some();
-        identifier.0 == "a";
-        default == Some(Default {
-            assign: term!(=),
-            value: DefaultValue::Integer(IntegerLit::Dec(DecLit("5"))),
-        });
-    });
-}
diff --git a/third_party/rust/weedle/src/attribute.rs b/third_party/rust/weedle/src/attribute.rs
deleted file mode 100644
index 0a70450023..0000000000
--- a/third_party/rust/weedle/src/attribute.rs
+++ /dev/null
@@ -1,99 +0,0 @@
-use crate::argument::ArgumentList;
-use crate::common::{Bracketed, Identifier, Parenthesized, Punctuated};
-use crate::literal::StringLit;
-
-/// Parses a list of attributes. Ex: `[ attribute1, attribute2 ]`
-pub type ExtendedAttributeList<'a> = Bracketed<Punctuated<ExtendedAttribute<'a>, term!(,)>>;
-
-/// Matches comma separated identifier list
-pub type IdentifierList<'a> = Punctuated<Identifier<'a>, term!(,)>;
-
-ast_types! {
-    /// Parses on of the forms of attribute
-    enum ExtendedAttribute<'a> {
-        /// Parses an argument list. Ex: `Constructor((double x, double y))`
-        ///
-        /// (( )) means ( ) chars
-        ArgList(struct ExtendedAttributeArgList<'a> {
-            identifier: Identifier<'a>,
-            args: Parenthesized<ArgumentList<'a>>,
-        }),
-        /// Parses a named argument list. Ex: `NamedConstructor=Image((DOMString src))`
-        ///
-        /// (( )) means ( ) chars
-        NamedArgList(struct ExtendedAttributeNamedArgList<'a> {
-            lhs_identifier: Identifier<'a>,
-            assign: term!(=),
-            rhs_identifier: Identifier<'a>,
-            args: Parenthesized<ArgumentList<'a>>,
-
-        }),
-        /// Parses an identifier list. Ex: `Exposed=((Window,Worker))`
-        ///
-        /// (( )) means ( ) chars
-        IdentList(struct ExtendedAttributeIdentList<'a> {
-            identifier: Identifier<'a>,
-            assign: term!(=),
-            list: Parenthesized<IdentifierList<'a>>,
-        }),
-        /// Parses an attribute with an identifier. Ex: `PutForwards=name`
-        #[derive(Copy)]
-        Ident(struct ExtendedAttributeIdent<'a> {
-            lhs_identifier: Identifier<'a>,
-            assign: term!(=),
-            rhs: IdentifierOrString<'a>,
-        }),
-        /// Parses a plain attribute. Ex: `Replaceable`
-        #[derive(Copy)]
-        NoArgs(struct ExtendedAttributeNoArgs<'a>(
-            Identifier<'a>,
-        )),
-    }
-
-    /// Parses `stringifier|static`
-    #[derive(Copy)]
-    enum IdentifierOrString<'a> {
-        Identifier(Identifier<'a>),
-        String(StringLit<'a>),
-    }
-}
-
-#[cfg(test)]
-mod test {
-    use super::*;
-    use crate::Parse;
-
-    test!(should_parse_attribute_no_args { "Replaceable" =>
-        "";
-        ExtendedAttributeNoArgs => ExtendedAttributeNoArgs(Identifier("Replaceable"))
-    });
-
-    test!(should_parse_attribute_arg_list { "Constructor(double x, double y)" =>
-        "";
-        ExtendedAttributeArgList;
-        identifier.0 == "Constructor";
-        args.body.list.len() == 2;
-    });
-
-    test!(should_parse_attribute_ident { "PutForwards=name" =>
-        "";
-        ExtendedAttributeIdent;
-        lhs_identifier.0 == "PutForwards";
-        rhs == IdentifierOrString::Identifier(Identifier("name"));
-    });
-
-    test!(should_parse_ident_list { "Exposed=(Window,Worker)" =>
-        "";
-        ExtendedAttributeIdentList;
-        identifier.0 == "Exposed";
-        list.body.list.len() == 2;
-    });
-
-    test!(should_parse_named_arg_list { "NamedConstructor=Image(DOMString src)" =>
-        "";
-        ExtendedAttributeNamedArgList;
-        lhs_identifier.0 == "NamedConstructor";
-        rhs_identifier.0 == "Image";
-        args.body.list.len() == 1;
-    });
-}
diff --git a/third_party/rust/weedle/src/common.rs b/third_party/rust/weedle/src/common.rs
deleted file mode 100644
index 81c6aa21a0..0000000000
--- a/third_party/rust/weedle/src/common.rs
+++ /dev/null
@@ -1,208 +0,0 @@
-use crate::literal::DefaultValue;
-use crate::term;
-use crate::Parse;
-
-impl<'a, T: Parse<'a>> Parse<'a> for Option<T> {
-    parser!(opt!(weedle!(T)));
-}
-
-impl<'a, T: Parse<'a>> Parse<'a> for Box<T> {
-    parser!(do_parse!(inner: weedle!(T) >> (Box::new(inner))));
-}
-
-/// Parses `item1 item2 item3...`
-impl<'a, T: Parse<'a>> Parse<'a> for Vec<T> {
-    parser!(many0!(weedle!(T)));
-}
-
-impl<'a, T: Parse<'a>, U: Parse<'a>> Parse<'a> for (T, U) {
-    parser!(do_parse!(t: weedle!(T) >> u: weedle!(U) >> ((t, u))));
-}
-
-impl<'a, T: Parse<'a>, U: Parse<'a>, V: Parse<'a>> Parse<'a> for (T, U, V) {
-    parser!(do_parse!(
-        t: weedle!(T) >> u: weedle!(U) >> v: weedle!(V) >> ((t, u, v))
-    ));
-}
-
-ast_types! {
-    /// Parses `( body )`
-    #[derive(Copy, Default)]
-    struct Parenthesized<T> where [T: Parse<'a>] {
-        open_paren: term::OpenParen,
-        body: T,
-        close_paren: term::CloseParen,
-    }
-
-    /// Parses `[ body ]`
-    #[derive(Copy, Default)]
-    struct Bracketed<T> where [T: Parse<'a>] {
-        open_bracket: term::OpenBracket,
-        body: T,
-        close_bracket: term::CloseBracket,
-    }
-
-    /// Parses `{ body }`
-    #[derive(Copy, Default)]
-    struct Braced<T> where [T: Parse<'a>] {
-        open_brace: term::OpenBrace,
-        body: T,
-        close_brace: term::CloseBrace,
-    }
-
-    /// Parses `< body >`
-    #[derive(Copy, Default)]
-    struct Generics<T> where [T: Parse<'a>] {
-        open_angle: term::LessThan,
-        body: T,
-        close_angle: term::GreaterThan,
-    }
-
-    /// Parses `(item1, item2, item3,...)?`
-    struct Punctuated<T, S> where [T: Parse<'a>, S: Parse<'a> + ::std::default::Default] {
-        list: Vec<T> = separated_list!(weedle!(S), weedle!(T)),
-        separator: S = marker,
-    }
-
-    /// Parses `item1, item2, item3, ...`
-    struct PunctuatedNonEmpty<T, S> where [T: Parse<'a>, S: Parse<'a> + ::std::default::Default] {
-        list: Vec<T> = terminated!(
-            separated_nonempty_list!(weedle!(S), weedle!(T)),
-            opt!(weedle!(S))
-        ),
-        separator: S = marker,
-    }
-
-    /// Represents an identifier
-    ///
-    /// Follows `/_?[A-Za-z][0-9A-Z_a-z-]*/`
-    #[derive(Copy)]
-    struct Identifier<'a>(
-        // See https://heycam.github.io/webidl/#idl-names for why the leading
-        // underscore is trimmed
-        &'a str = ws!(do_parse!(
-            opt!(char!('_')) >>
-            id: recognize!(do_parse!(
-                take_while1!(|c: char| c.is_ascii_alphabetic()) >>
-                take_while!(|c: char| c.is_ascii_alphanumeric() || c == '_' || c == '-') >>
-                (())
-            )) >>
-            (id)
-        )),
-    )
-
-    /// Parses rhs of an assignment expression. Ex: `= 45`
-    #[derive(Copy)]
-    struct Default<'a> {
-        assign: term!(=),
-        value: DefaultValue<'a>,
-    }
-}
-
-#[cfg(test)]
-mod test {
-    use super::*;
-
-    test!(should_parse_optional_present { "one" =>
-        "";
-        Option<Identifier>;
-        is_some();
-    });
-
-    test!(should_parse_optional_not_present { "" =>
-        "";
-        Option<Identifier>;
-        is_none();
-    });
-
-    test!(should_parse_boxed { "one" =>
-        "";
-        Box<Identifier>;
-    });
-
-    test!(should_parse_vec { "one two three" =>
-        "";
-        Vec<Identifier>;
-        len() == 3;
-    });
-
-    test!(should_parse_parenthesized { "( one )" =>
-        "";
-        Parenthesized<Identifier>;
-        body.0 == "one";
-    });
-
-    test!(should_parse_bracketed { "[ one ]" =>
-        "";
-        Bracketed<Identifier>;
-        body.0 == "one";
-    });
-
-    test!(should_parse_braced { "{ one }" =>
-        "";
-        Braced<Identifier>;
-        body.0 == "one";
-    });
-
-    test!(should_parse_generics { "<one>" =>
-        "";
-        Generics<Identifier>;
-        body.0 == "one";
-    });
-
-    test!(should_parse_generics_two { "<one, two>" =>
-        "";
-        Generics<(Identifier, term!(,), Identifier)> =>
-            Generics {
-                open_angle: term!(<),
-                body: (Identifier("one"), term!(,), Identifier("two")),
-                close_angle: term!(>),
-            }
-    });
-
-    test!(should_parse_comma_separated_values { "one, two, three" =>
-        "";
-        Punctuated<Identifier, term!(,)>;
-        list.len() == 3;
-    });
-
-    test!(err should_not_parse_comma_separated_values_empty { "" =>
-        PunctuatedNonEmpty<Identifier, term!(,)>
-    });
-
-    test!(should_parse_identifier { "hello" =>
-        "";
-        Identifier;
-        0 == "hello";
-    });
-
-    test!(should_parse_numbered_identifier { "hello5" =>
-        "";
-        Identifier;
-        0 == "hello5";
-    });
-
-    test!(should_parse_underscored_identifier { "_hello_" =>
-        "";
-        Identifier;
-        0 == "hello_";
-    });
-
-    test!(should_parse_identifier_surrounding_with_spaces { "  hello  " =>
-        "";
-        Identifier;
-        0 == "hello";
-    });
-
-    test!(should_parse_identifier_preceeding_others { "hello  note" =>
-        "note";
-        Identifier;
-        0 == "hello";
-    });
-
-    test!(should_parse_identifier_attached_to_symbol { "hello=" =>
-        "=";
-        Identifier;
-        0 == "hello";
-    });
-}
diff --git a/third_party/rust/weedle/src/dictionary.rs b/third_party/rust/weedle/src/dictionary.rs
deleted file mode 100644
index 3c9b23cac5..0000000000
--- a/third_party/rust/weedle/src/dictionary.rs
+++ /dev/null
@@ -1,33 +0,0 @@
-use crate::attribute::ExtendedAttributeList;
-use crate::common::{Default, Identifier};
-use crate::types::Type;
-
-/// Parses dictionary members
-pub type DictionaryMembers<'a> = Vec<DictionaryMember<'a>>;
-
-ast_types! {
-    /// Parses dictionary member `[attributes]? required? type identifier ( = default )?;`
-    struct DictionaryMember<'a> {
-        attributes: Option<ExtendedAttributeList<'a>>,
-        required: Option<term!(required)>,
-        type_: Type<'a>,
-        identifier: Identifier<'a>,
-        default: Option<Default<'a>>,
-        semi_colon: term!(;),
-    }
-}
-
-#[cfg(test)]
-mod test {
-    use super::*;
-    use crate::Parse;
-
-    test!(should_parse_dictionary_member { "required long num = 5;" =>
-        "";
-        DictionaryMember;
-        attributes.is_none();
-        required.is_some();
-        identifier.0 == "num";
-        default.is_some();
-    });
-}
diff --git a/third_party/rust/weedle/src/interface.rs b/third_party/rust/weedle/src/interface.rs
deleted file mode 100644
index 27945669cb..0000000000
--- a/third_party/rust/weedle/src/interface.rs
+++ /dev/null
@@ -1,202 +0,0 @@
-use crate::argument::ArgumentList;
-use crate::attribute::ExtendedAttributeList;
-use crate::common::{Generics, Identifier, Parenthesized};
-use crate::literal::ConstValue;
-use crate::types::{AttributedType, ConstType, ReturnType};
-
-/// Parses interface members
-pub type InterfaceMembers<'a> = Vec<InterfaceMember<'a>>;
-
-ast_types! {
-    /// Parses inheritance clause `: identifier`
-    #[derive(Copy)]
-    struct Inheritance<'a> {
-        colon: term!(:),
-        identifier: Identifier<'a>,
-    }
-
-    /// Parses one of the interface member variants
-    enum InterfaceMember<'a> {
-        /// Parses a const interface member `[attributes]? const type identifier = value;`
-        Const(struct ConstMember<'a> {
-            attributes: Option<ExtendedAttributeList<'a>>,
-            const_: term!(const),
-            const_type: ConstType<'a>,
-            identifier: Identifier<'a>,
-            assign: term!(=),
-            const_value: ConstValue<'a>,
-            semi_colon: term!(;),
-        }),
-        /// Parses `[attributes]? (stringifier|inherit|static)? readonly? attribute attributedtype identifier;`
-        Attribute(struct AttributeInterfaceMember<'a> {
-            attributes: Option<ExtendedAttributeList<'a>>,
-            modifier: Option<StringifierOrInheritOrStatic>,
-            readonly: Option<term!(readonly)>,
-            attribute: term!(attribute),
-            type_: AttributedType<'a>,
-            identifier: Identifier<'a>,
-            semi_colon: term!(;),
-        }),
-        /// Parses `[attributes]? constructor(( args ));`
-        ///
-        /// (( )) means ( ) chars
-        Constructor(struct ConstructorInterfaceMember<'a> {
-            attributes: Option<ExtendedAttributeList<'a>>,
-            constructor: term!(constructor),
-            args: Parenthesized<ArgumentList<'a>>,
-            semi_colon: term!(;),
-        }),
-        /// Parses `[attributes]? (stringifier|static)? special? returntype identifier? (( args ));`
-        ///
-        /// (( )) means ( ) chars
-        Operation(struct OperationInterfaceMember<'a> {
-            attributes: Option<ExtendedAttributeList<'a>>,
-            modifier: Option<StringifierOrStatic>,
-            special: Option<Special>,
-            return_type: ReturnType<'a>,
-            identifier: Option<Identifier<'a>>,
-            args: Parenthesized<ArgumentList<'a>>,
-            semi_colon: term!(;),
-        }),
-        /// Parses an iterable declaration `[attributes]? (iterable<attributedtype> | iterable<attributedtype, attributedtype>) ;`
-        Iterable(enum IterableInterfaceMember<'a> {
-            /// Parses an iterable declaration `[attributes]? iterable<attributedtype>;`
-            Single(struct SingleTypedIterable<'a> {
-                attributes: Option<ExtendedAttributeList<'a>>,
-                iterable: term!(iterable),
-                generics: Generics<AttributedType<'a>>,
-                semi_colon: term!(;),
-            }),
-            /// Parses an iterable declaration `[attributes]? iterable<attributedtype, attributedtype>;`
-            Double(struct DoubleTypedIterable<'a> {
-                attributes: Option<ExtendedAttributeList<'a>>,
-                iterable: term!(iterable),
-                generics: Generics<(AttributedType<'a>, term!(,), AttributedType<'a>)>,
-                semi_colon: term!(;),
-            }),
-        }),
-        /// Parses an maplike declaration `[attributes]? readonly? maplike<attributedtype, attributedtype>;`
-        Maplike(struct MaplikeInterfaceMember<'a> {
-            attributes: Option<ExtendedAttributeList<'a>>,
-            readonly: Option<term!(readonly)>,
-            maplike: term!(maplike),
-            generics: Generics<(AttributedType<'a>, term!(,), AttributedType<'a>)>,
-            semi_colon: term!(;),
-        }),
-        Setlike(struct SetlikeInterfaceMember<'a> {
-            attributes: Option<ExtendedAttributeList<'a>>,
-            readonly: Option<term!(readonly)>,
-            setlike: term!(setlike),
-            generics: Generics<AttributedType<'a>>,
-            semi_colon: term!(;),
-        }),
-        /// Parses `stringifier;`
-        #[derive(Default)]
-        Stringifier(struct StringifierMember<'a> {
-            attributes: Option<ExtendedAttributeList<'a>>,
-            stringifier: term!(stringifier),
-            semi_colon: term!(;),
-        }),
-    }
-
-    /// Parses one of the special keyword `getter|setter|deleter`
-    #[derive(Copy)]
-    enum Special {
-        Getter(term!(getter)),
-        Setter(term!(setter)),
-        Deleter(term!(deleter)),
-        LegacyCaller(term!(legacycaller)),
-    }
-
-    /// Parses `stringifier|inherit|static`
-    #[derive(Copy)]
-    enum StringifierOrInheritOrStatic {
-        Stringifier(term!(stringifier)),
-        Inherit(term!(inherit)),
-        Static(term!(static)),
-    }
-
-    /// Parses `stringifier|static`
-    #[derive(Copy)]
-    enum StringifierOrStatic {
-        Stringifier(term!(stringifier)),
-        Static(term!(static)),
-    }
-}
-
-#[cfg(test)]
-mod test {
-    use super::*;
-    use crate::Parse;
-
-    test!(should_parse_stringifier_member { "stringifier;" =>
-        "";
-        StringifierMember;
-    });
-
-    test!(should_parse_stringifier_or_static { "static" =>
-        "";
-        StringifierOrStatic;
-    });
-
-    test!(should_parse_stringifier_or_inherit_or_static { "inherit" =>
-        "";
-        StringifierOrInheritOrStatic;
-    });
-
-    test!(should_parse_setlike_interface_member { "readonly setlike<long>;" =>
-        "";
-        SetlikeInterfaceMember;
-        attributes.is_none();
-        readonly == Some(term!(readonly));
-    });
-
-    test!(should_parse_maplike_interface_member { "readonly maplike<long, short>;" =>
-        "";
-        MaplikeInterfaceMember;
-        attributes.is_none();
-        readonly == Some(term!(readonly));
-    });
-
-    test!(should_parse_attribute_interface_member { "readonly attribute unsigned long width;" =>
-        "";
-        AttributeInterfaceMember;
-        attributes.is_none();
-        readonly == Some(term!(readonly));
-        identifier.0 == "width";
-    });
-
-    test!(should_parse_double_typed_iterable { "iterable<long, long>;" =>
-        "";
-        DoubleTypedIterable;
-        attributes.is_none();
-    });
-
-    test!(should_parse_single_typed_iterable { "iterable<long>;" =>
-        "";
-        SingleTypedIterable;
-        attributes.is_none();
-    });
-
-    test!(should_parse_constructor_interface_member { "constructor(long a);" =>
-        "";
-        ConstructorInterfaceMember;
-        attributes.is_none();
-    });
-
-    test!(should_parse_operation_interface_member { "void readString(long a, long b);" =>
-        "";
-        OperationInterfaceMember;
-        attributes.is_none();
-        modifier.is_none();
-        special.is_none();
-        identifier.is_some();
-    });
-
-    test!(should_parse_const_member { "const long name = 5;" =>
-        "";
-        ConstMember;
-        attributes.is_none();
-        identifier.0 == "name";
-    });
-}
diff --git a/third_party/rust/weedle/src/lib.rs b/third_party/rust/weedle/src/lib.rs
deleted file mode 100644
index 1b7bef8473..0000000000
--- a/third_party/rust/weedle/src/lib.rs
+++ /dev/null
@@ -1,425 +0,0 @@
-//! Weedle - A WebIDL Parser
-//!
-//! Parses valid WebIDL definitions & produces a data structure starting from
-//! [`Definitions`](struct.Definitions.html).
-//!
-//! ### Example
-//!
-//! ```
-//! extern crate weedle;
-//!
-//! let parsed = weedle::parse("
-//!     interface Window {
-//!         readonly attribute Storage sessionStorage;
-//!     };
-//! ").unwrap();
-//! println!("{:?}", parsed);
-//! ```
-//!
-//! Note:
-//! This parser follows the grammar given at [WebIDL](https://heycam.github.io/webidl).
-//!
-//! If any flaws found when parsing string with a valid grammar, create an issue.
-
-// need a higher recusion limit for macros
-#![recursion_limit = "128"]
-
-#[macro_use(
-    alt,
-    cond,
-    do_parse,
-    map,
-    many0,
-    opt,
-    recognize,
-    separated_list,
-    separated_nonempty_list,
-    terminated
-)]
-extern crate nom;
-
-use self::argument::ArgumentList;
-use self::attribute::ExtendedAttributeList;
-use self::common::{Braced, Identifier, Parenthesized, PunctuatedNonEmpty};
-use self::dictionary::DictionaryMembers;
-use self::interface::{Inheritance, InterfaceMembers};
-use self::literal::StringLit;
-use self::mixin::MixinMembers;
-use self::namespace::NamespaceMembers;
-use self::types::{AttributedType, ReturnType};
-pub use nom::{error::ErrorKind, Err, IResult};
-
-#[macro_use]
-mod macros;
-#[macro_use]
-mod whitespace;
-#[macro_use]
-pub mod term;
-pub mod argument;
-pub mod attribute;
-pub mod common;
-pub mod dictionary;
-pub mod interface;
-pub mod literal;
-pub mod mixin;
-pub mod namespace;
-pub mod types;
-
-/// A convenient parse function
-///
-/// ### Example
-///
-/// ```
-/// extern crate weedle;
-///
-/// let parsed = weedle::parse("
-///     interface Window {
-///         readonly attribute Storage sessionStorage;
-///     };
-/// ").unwrap();
-///
-/// println!("{:?}", parsed);
-/// ```
-pub fn parse(raw: &str) -> Result<Definitions<'_>, Err<(&str, ErrorKind)>> {
-    let (remaining, parsed) = Definitions::parse(raw)?;
-    assert!(
-        remaining.is_empty(),
-        "There is redundant raw data after parsing"
-    );
-    Ok(parsed)
-}
-
-pub trait Parse<'a>: Sized {
-    fn parse(input: &'a str) -> IResult<&'a str, Self>;
-}
-
-/// Parses WebIDL definitions. It is the root struct for a complete WebIDL definition.
-///
-/// ### Example
-/// ```
-/// use weedle::{Definitions, Parse};
-///
-/// let (_, parsed) = Definitions::parse("
-///     interface Window {
-///         readonly attribute Storage sessionStorage;
-///     };
-/// ").unwrap();
-///
-/// println!("{:?}", parsed);
-/// ```
-///
-/// It is recommended to use [`parse`](fn.parse.html) instead.
-pub type Definitions<'a> = Vec<Definition<'a>>;
-
-ast_types! {
-    /// Parses a definition
-    enum Definition<'a> {
-        /// Parses `[attributes]? callback identifier = type ( (arg1, arg2, ..., argN)? );`
-        Callback(struct CallbackDefinition<'a> {
-            attributes: Option<ExtendedAttributeList<'a>>,
-            callback: term!(callback),
-            identifier: Identifier<'a>,
-            assign: term!(=),
-            return_type: ReturnType<'a>,
-            arguments: Parenthesized<ArgumentList<'a>>,
-            semi_colon: term!(;),
-        }),
-        /// Parses `[attributes]? callback interface identifier ( : inheritance )? { members };`
-        CallbackInterface(struct CallbackInterfaceDefinition<'a> {
-            attributes: Option<ExtendedAttributeList<'a>>,
-            callback: term!(callback),
-            interface: term!(interface),
-            identifier: Identifier<'a>,
-            inheritance: Option<Inheritance<'a>>,
-            members: Braced<InterfaceMembers<'a>>,
-            semi_colon: term!(;),
-        }),
-        /// Parses `[attributes]? interface identifier ( : inheritance )? { members };`
-        Interface(struct InterfaceDefinition<'a> {
-            attributes: Option<ExtendedAttributeList<'a>>,
-            interface: term!(interface),
-            identifier: Identifier<'a>,
-            inheritance: Option<Inheritance<'a>>,
-            members: Braced<InterfaceMembers<'a>>,
-            semi_colon: term!(;),
-        }),
-        /// Parses `[attributes]? interface mixin identifier { members };`
-        InterfaceMixin(struct InterfaceMixinDefinition<'a> {
-            attributes: Option<ExtendedAttributeList<'a>>,
-            interface: term!(interface),
-            mixin: term!(mixin),
-            identifier: Identifier<'a>,
-            members: Braced<MixinMembers<'a>>,
-            semi_colon: term!(;),
-        }),
-        /// Parses `[attributes]? namespace identifier { members };`
-        Namespace(struct NamespaceDefinition<'a> {
-            attributes: Option<ExtendedAttributeList<'a>>,
-            namespace: term!(namespace),
-            identifier: Identifier<'a>,
-            members: Braced<NamespaceMembers<'a>>,
-            semi_colon: term!(;),
-        }),
-        /// Parses `[attributes]? dictionary identifier ( : inheritance )? { members };`
-        Dictionary(struct DictionaryDefinition<'a> {
-            attributes: Option<ExtendedAttributeList<'a>>,
-            dictionary: term!(dictionary),
-            identifier: Identifier<'a>,
-            inheritance: Option<Inheritance<'a>>,
-            members: Braced<DictionaryMembers<'a>>,
-            semi_colon: term!(;),
-        }),
-        /// Parses `[attributes]? partial interface identifier { members };`
-        PartialInterface(struct PartialInterfaceDefinition<'a> {
-            attributes: Option<ExtendedAttributeList<'a>>,
-            partial: term!(partial),
-            interface: term!(interface),
-            identifier: Identifier<'a>,
-            members: Braced<InterfaceMembers<'a>>,
-            semi_colon: term!(;),
-        }),
-        /// Parses `[attributes]? partial interface mixin identifier { members };`
-        PartialInterfaceMixin(struct PartialInterfaceMixinDefinition<'a> {
-            attributes: Option<ExtendedAttributeList<'a>>,
-            partial: term!(partial),
-            interface: term!(interface),
-            mixin: term!(mixin),
-            identifier: Identifier<'a>,
-            members: Braced<MixinMembers<'a>>,
-            semi_colon: term!(;),
-        }),
-        /// Parses `[attributes]? partial dictionary identifier { members };`
-        PartialDictionary(struct PartialDictionaryDefinition<'a> {
-            attributes: Option<ExtendedAttributeList<'a>>,
-            partial: term!(partial),
-            dictionary: term!(dictionary),
-            identifier: Identifier<'a>,
-            members: Braced<DictionaryMembers<'a>>,
-            semi_colon: term!(;),
-        }),
-        /// Parses `[attributes]? partial namespace identifier { members };`
-        PartialNamespace(struct PartialNamespaceDefinition<'a> {
-            attributes: Option<ExtendedAttributeList<'a>>,
-            partial: term!(partial),
-            namespace: term!(namespace),
-            identifier: Identifier<'a>,
-            members: Braced<NamespaceMembers<'a>>,
-            semi_colon: term!(;),
-        }),
-        /// Parses `[attributes]? enum identifier { values };`
-        Enum(struct EnumDefinition<'a> {
-            attributes: Option<ExtendedAttributeList<'a>>,
-            enum_: term!(enum),
-            identifier: Identifier<'a>,
-            values: Braced<EnumValueList<'a>>,
-            semi_colon: term!(;),
-        }),
-        /// Parses `[attributes]? typedef attributedtype identifier;`
-        Typedef(struct TypedefDefinition<'a> {
-            attributes: Option<ExtendedAttributeList<'a>>,
-            typedef: term!(typedef),
-            type_: AttributedType<'a>,
-            identifier: Identifier<'a>,
-            semi_colon: term!(;),
-        }),
-        /// Parses `[attributes]? identifier includes identifier;`
-        IncludesStatement(struct IncludesStatementDefinition<'a> {
-            attributes: Option<ExtendedAttributeList<'a>>,
-            lhs_identifier: Identifier<'a>,
-            includes: term!(includes),
-            rhs_identifier: Identifier<'a>,
-            semi_colon: term!(;),
-        }),
-        /// Parses `[attributes]? identifier implements identifier;`
-        Implements(struct ImplementsDefinition<'a> {
-            attributes: Option<ExtendedAttributeList<'a>>,
-            lhs_identifier: Identifier<'a>,
-            includes: term!(implements),
-            rhs_identifier: Identifier<'a>,
-            semi_colon: term!(;),
-        }),
-    }
-}
-
-/// Parses a non-empty enum value list
-pub type EnumValueList<'a> = PunctuatedNonEmpty<StringLit<'a>, term!(,)>;
-
-#[cfg(test)]
-mod test {
-    use super::*;
-
-    test!(should_parse_includes_statement { "first includes second;" =>
-        "";
-        IncludesStatementDefinition;
-        attributes.is_none();
-        lhs_identifier.0 == "first";
-        rhs_identifier.0 == "second";
-    });
-
-    test!(should_parse_typedef { "typedef short Short;" =>
-        "";
-        TypedefDefinition;
-        attributes.is_none();
-        identifier.0 == "Short";
-    });
-
-    test!(should_parse_enum { r#"enum name { "first", "second" }; "# =>
-        "";
-        EnumDefinition;
-        attributes.is_none();
-        identifier.0 == "name";
-        values.body.list.len() == 2;
-    });
-
-    test!(should_parse_dictionary { "dictionary A { long c; long g; };" =>
-        "";
-        DictionaryDefinition;
-        attributes.is_none();
-        identifier.0 == "A";
-        inheritance.is_none();
-        members.body.len() == 2;
-    });
-
-    test!(should_parse_dictionary_inherited { "dictionary C : B { long e; long f; };" =>
-        "";
-        DictionaryDefinition;
-        attributes.is_none();
-        identifier.0 == "C";
-        inheritance.is_some();
-        members.body.len() == 2;
-    });
-
-    test!(should_parse_partial_namespace { "
-        partial namespace VectorUtils {
-            readonly attribute Vector unit;
-            double dotProduct(Vector x, Vector y);
-            Vector crossProduct(Vector x, Vector y);
-        };
-    " =>
-        "";
-        PartialNamespaceDefinition;
-        attributes.is_none();
-        identifier.0 == "VectorUtils";
-        members.body.len() == 3;
-    });
-
-    test!(should_parse_partial_dictionary { "partial dictionary C { long e; long f; };" =>
-        "";
-        PartialDictionaryDefinition;
-        attributes.is_none();
-        identifier.0 == "C";
-        members.body.len() == 2;
-    });
-
-    test!(should_parse_partial_interface_mixin { "
-        partial interface mixin WindowSessionStorage {
-          readonly attribute Storage sessionStorage;
-        };
-    " =>
-        "";
-        PartialInterfaceMixinDefinition;
-        attributes.is_none();
-        identifier.0 == "WindowSessionStorage";
-        members.body.len() == 1;
-    });
-
-    test!(should_parse_partial_interface { "
-        partial interface Window {
-          readonly attribute Storage sessionStorage;
-        };
-    " =>
-        "";
-        PartialInterfaceDefinition;
-        attributes.is_none();
-        identifier.0 == "Window";
-        members.body.len() == 1;
-    });
-
-    test!(should_parse_namespace { "
-        namespace VectorUtils {
-          readonly attribute Vector unit;
-          double dotProduct(Vector x, Vector y);
-          Vector crossProduct(Vector x, Vector y);
-        };
-    " =>
-        "";
-        NamespaceDefinition;
-        attributes.is_none();
-        identifier.0 == "VectorUtils";
-        members.body.len() == 3;
-    });
-
-    test!(should_parse_interface_mixin { "
-        interface mixin WindowSessionStorage {
-          readonly attribute Storage sessionStorage;
-        };
-    " =>
-        "";
-        InterfaceMixinDefinition;
-        attributes.is_none();
-        identifier.0 == "WindowSessionStorage";
-        members.body.len() == 1;
-    });
-
-    test!(should_parse_interface { "
-        interface Window {
-          readonly attribute Storage sessionStorage;
-        };
-    " =>
-        "";
-        InterfaceDefinition;
-        attributes.is_none();
-        identifier.0 == "Window";
-        members.body.len() == 1;
-    });
-
-    test!(should_parse_callback_interface {"
-        callback interface Options {
-          attribute DOMString? option1;
-          attribute DOMString? option2;
-          attribute long? option3;
-        };
-    " =>
-        "";
-        CallbackInterfaceDefinition;
-        attributes.is_none();
-        identifier.0 == "Options";
-        members.body.len() == 3;
-    });
-
-    test!(should_parse_callback { "callback AsyncOperationCallback = void (DOMString status);" =>
-        "";
-        CallbackDefinition;
-        attributes.is_none();
-        identifier.0 == "AsyncOperationCallback";
-        arguments.body.list.len() == 1;
-    });
-
-    test!(should_parse_with_line_comments { "
-        // This is a comment
-        callback AsyncOperationCallback = void (DOMString status);
-    " =>
-        "";
-        CallbackDefinition;
-    });
-
-    test!(should_parse_with_block_comments { "
-        /* This is a comment */
-        callback AsyncOperationCallback = void (DOMString status);
-    " =>
-        "";
-        CallbackDefinition;
-    });
-
-    test!(should_parse_with_multiple_comments { "
-        // This is a comment
-        // This is a comment
-        // This is a comment
-
-        // This is a comment
-        callback AsyncOperationCallback = void (DOMString status);
-    " =>
-        "";
-        CallbackDefinition;
-    });
-}
diff --git a/third_party/rust/weedle/src/literal.rs b/third_party/rust/weedle/src/literal.rs
deleted file mode 100644
index 34d9bb1421..0000000000
--- a/third_party/rust/weedle/src/literal.rs
+++ /dev/null
@@ -1,281 +0,0 @@
-ast_types! {
-    /// Represents an integer value
-    #[derive(Copy)]
-    enum IntegerLit<'a> {
-        /// Parses `-?[1-9][0-9]*`
-        #[derive(Copy)]
-        Dec(struct DecLit<'a>(
-            &'a str = ws!(recognize!(do_parse!(
-                opt!(char!('-')) >>
-                one_of!("123456789") >>
-                take_while!(|c: char| c.is_ascii_digit()) >>
-                (())
-            ))),
-        )),
-        /// Parses `-?0[Xx][0-9A-Fa-f]+)`
-        #[derive(Copy)]
-        Hex(struct HexLit<'a>(
-            &'a str = ws!(recognize!(do_parse!(
-                opt!(char!('-')) >>
-                char!('0') >>
-                alt!(char!('x') | char!('X')) >>
-                take_while!(|c: char| c.is_ascii_hexdigit()) >>
-                (())
-            ))),
-        )),
-        /// Parses `-?0[0-7]*`
-        #[derive(Copy)]
-        Oct(struct OctLit<'a>(
-            &'a str = ws!(recognize!(do_parse!(
-                opt!(char!('-')) >>
-                char!('0') >>
-                take_while!(|c| '0' <= c && c <= '7') >>
-                (())
-            ))),
-        )),
-    }
-
-    /// Represents a string value
-    ///
-    /// Follow `/"[^"]*"/`
-    #[derive(Copy)]
-    struct StringLit<'a>(
-        &'a str = ws!(do_parse!(
-            char!('"') >>
-            s: take_while!(|c| c != '"') >>
-            char!('"') >>
-            (s)
-        )),
-    )
-
-    /// Represents a default literal value. Ex: `34|34.23|"value"|[ ]|true|false|null`
-    #[derive(Copy)]
-    enum DefaultValue<'a> {
-        Boolean(BooleanLit),
-        /// Represents `[ ]`
-        #[derive(Copy, Default)]
-        EmptyArray(struct EmptyArrayLit {
-            open_bracket: term!(OpenBracket),
-            close_bracket: term!(CloseBracket),
-        }),
-        /// Represents `{ }`
-        #[derive(Copy, Default)]
-        EmptyDictionary(struct EmptyDictionaryLit {
-            open_brace: term!(OpenBrace),
-            close_brace: term!(CloseBrace),
-        }),
-        Float(FloatLit<'a>),
-        Integer(IntegerLit<'a>),
-        Null(term!(null)),
-        String(StringLit<'a>),
-    }
-
-    /// Represents `true`, `false`, `34.23`, `null`, `56`, ...
-    #[derive(Copy)]
-    enum ConstValue<'a> {
-        Boolean(BooleanLit),
-        Float(FloatLit<'a>),
-        Integer(IntegerLit<'a>),
-        Null(term!(null)),
-    }
-
-    /// Represents either `true` or `false`
-    #[derive(Copy)]
-    struct BooleanLit(
-        bool = alt!(
-            weedle!(term!(true)) => {|_| true} |
-            weedle!(term!(false)) => {|_| false}
-        ),
-    )
-
-    /// Represents a floating point value, `NaN`, `Infinity`, '+Infinity`
-    #[derive(Copy)]
-    enum FloatLit<'a> {
-        /// Parses `/-?(([0-9]+\.[0-9]*|[0-9]*\.[0-9]+)([Ee][+-]?[0-9]+)?|[0-9]+[Ee][+-]?[0-9]+)/`
-        #[derive(Copy)]
-        Value(struct FloatValueLit<'a>(
-            &'a str = ws!(recognize!(do_parse!(
-                opt!(char!('-')) >>
-                alt!(
-                    do_parse!(
-                        // (?:[0-9]+\.[0-9]*|[0-9]*\.[0-9]+)
-                        alt!(
-                            do_parse!(
-                                take_while1!(|c: char| c.is_ascii_digit()) >>
-                                char!('.') >>
-                                take_while!(|c: char| c.is_ascii_digit()) >>
-                                (())
-                            )
-                            |
-                            do_parse!(
-                                take_while!(|c: char| c.is_ascii_digit()) >>
-                                char!('.') >>
-                                take_while1!(|c: char| c.is_ascii_digit()) >>
-                                (())
-                            )
-                        ) >>
-                        // (?:[Ee][+-]?[0-9]+)?
-                        opt!(do_parse!(
-                            alt!(char!('e') | char!('E')) >>
-                            opt!(alt!(char!('+') | char!('-'))) >>
-                            take_while1!(|c: char| c.is_ascii_digit()) >>
-                            (())
-                        )) >>
-                        (())
-                    )
-                    |
-                    // [0-9]+[Ee][+-]?[0-9]+
-                    do_parse!(
-                        take_while1!(|c: char| c.is_ascii_digit()) >>
-                        alt!(char!('e') | char!('E')) >>
-                        opt!(alt!(char!('+') | char!('-'))) >>
-                        take_while1!(|c: char| c.is_ascii_digit()) >>
-                        (())
-                    )
-                ) >>
-                (())
-            ))),
-        )),
-        NegInfinity(term!(-Infinity)),
-        Infinity(term!(Infinity)),
-        NaN(term!(NaN)),
-    }
-}
-
-#[cfg(test)]
-mod test {
-    use super::*;
-    use crate::term::*;
-    use crate::Parse;
-
-    test!(should_parse_integer { "45" =>
-        "";
-        IntegerLit => IntegerLit::Dec(DecLit("45"))
-    });
-
-    test!(should_parse_integer_surrounding_with_spaces { "  123123  " =>
-        "";
-        IntegerLit => IntegerLit::Dec(DecLit("123123"))
-    });
-
-    test!(should_parse_integer_preceeding_others { "3453 string" =>
-        "string";
-        IntegerLit => IntegerLit::Dec(DecLit("3453"))
-    });
-
-    test!(should_parse_neg_integer { "-435" =>
-        "";
-        IntegerLit => IntegerLit::Dec(DecLit("-435"))
-    });
-
-    test!(should_parse_hex_number { "0X08" =>
-        "";
-        IntegerLit => IntegerLit::Hex(HexLit("0X08"))
-    });
-
-    test!(should_parse_hex_large_number { "0xA" =>
-        "";
-        IntegerLit => IntegerLit::Hex(HexLit("0xA"))
-    });
-
-    test!(should_parse_zero { "0" =>
-        "";
-        IntegerLit => IntegerLit::Oct(OctLit("0"))
-    });
-
-    test!(should_parse_oct_number { "-07561" =>
-        "";
-        IntegerLit => IntegerLit::Oct(OctLit("-07561"))
-    });
-
-    test!(should_parse_float { "45.434" =>
-        "";
-        FloatLit => FloatLit::Value(FloatValueLit("45.434"))
-    });
-
-    test!(should_parse_float_surrounding_with_spaces { "  2345.2345  " =>
-        "";
-        FloatLit => FloatLit::Value(FloatValueLit("2345.2345"))
-    });
-
-    test!(should_parse_float_preceeding_others { "3453.32334 string" =>
-        "string";
-        FloatLit => FloatLit::Value(FloatValueLit("3453.32334"))
-    });
-
-    test!(should_parse_neg_float { "-435.3435" =>
-        "";
-        FloatLit => FloatLit::Value(FloatValueLit("-435.3435"))
-    });
-
-    test!(should_parse_float_exp { "5.3434e23" =>
-        "";
-        FloatLit => FloatLit::Value(FloatValueLit("5.3434e23"))
-    });
-
-    test!(should_parse_float_exp_with_decimal { "3e23" =>
-        "";
-        FloatLit => FloatLit::Value(FloatValueLit("3e23"))
-    });
-
-    test!(should_parse_neg_infinity { "-Infinity" =>
-        "";
-        FloatLit => FloatLit::NegInfinity(term!(-Infinity))
-    });
-
-    test!(should_parse_infinity { "Infinity" =>
-        "";
-        FloatLit => FloatLit::Infinity(term!(Infinity))
-    });
-
-    test!(should_parse_string { r#""this is a string""# =>
-        "";
-        StringLit => StringLit("this is a string")
-    });
-
-    test!(should_parse_string_surround_with_spaces { r#"  "this is a string"  "# =>
-        "";
-        StringLit => StringLit("this is a string")
-    });
-
-    test!(should_parse_string_followed_by_string { r#" "this is first"  "this is second" "# =>
-        r#""this is second" "#;
-        StringLit => StringLit("this is first")
-    });
-
-    test!(should_parse_string_with_spaces { r#"  "  this is a string  "  "# =>
-        "";
-        StringLit => StringLit("  this is a string  ")
-    });
-
-    test!(should_parse_string_with_comment { r#"  "// this is still a string"
-     "# =>
-        "";
-        StringLit => StringLit("// this is still a string")
-    });
-
-    test!(should_parse_string_with_multiline_comment { r#"  "/*"  "*/"  "# =>
-        r#""*/"  "#;
-        StringLit => StringLit("/*")
-    });
-
-    test!(should_parse_null { "null" =>
-        "";
-        Null => Null
-    });
-
-    test!(should_parse_empty_array { "[]" =>
-        "";
-        EmptyArrayLit => Default::default()
-    });
-
-    test!(should_parse_bool_true { "true" =>
-        "";
-        BooleanLit => BooleanLit(true)
-    });
-
-    test!(should_parse_bool_false { "false" =>
-        "";
-        BooleanLit => BooleanLit(false)
-    });
-}
diff --git a/third_party/rust/weedle/src/macros.rs b/third_party/rust/weedle/src/macros.rs
deleted file mode 100644
index cb55a1bc23..0000000000
--- a/third_party/rust/weedle/src/macros.rs
+++ /dev/null
@@ -1,614 +0,0 @@
-macro_rules! tag {
-    ($i:expr, $tag: expr) => {
-        nom::bytes::complete::tag($tag)($i)
-    };
-}
-
-macro_rules! take_while {
-    ($input:expr, $submac:ident!( $($args:tt)* )) => {
-        $crate::macros::take_while!($input, (|c| $submac!(c, $($args)*)))
-    };
-    ($input:expr, $f:expr) => {
-        nom::bytes::complete::take_while($f)($input)
-    };
-}
-
-macro_rules! take_while1 {
-    ($input:expr, $submac:ident!( $($args:tt)* )) => {
-        $crate::macros::take_while1!($input, (|c| $submac!(c, $($args)*)))
-    };
-    ($input:expr, $f:expr) => {
-        nom::bytes::complete::take_while1($f)($input)
-    };
-}
-
-macro_rules! take_until {
-    ($i:expr, $substr:expr) => {
-        nom::bytes::complete::take_until($substr)($i)
-    };
-}
-
-macro_rules! one_of {
-    ($i:expr, $inp: expr) => {
-        nom::character::complete::one_of($inp)($i)
-    };
-}
-
-macro_rules! char {
-    ($i:expr, $c: expr) => {
-        nom::character::complete::char($c)($i)
-    };
-}
-
-macro_rules! parser {
-    ($submac:ident!( $($args:tt)* )) => {
-        fn parse(input: &'a str) -> $crate::IResult<&'a str, Self> {
-            $submac!(input, $($args)*)
-        }
-    };
-}
-
-macro_rules! weedle {
-    ($i:expr, $t:ty) => {
-        <$t as $crate::Parse<'a>>::parse($i)
-    };
-}
-
-macro_rules! ast_types {
-    (@extract_type struct $name:ident<'a> $($rest:tt)*) => ($name<'a>);
-    (@extract_type struct $name:ident $($rest:tt)*) => ($name);
-    (@extract_type enum $name:ident<'a> $($rest:tt)*) => ($name<'a>);
-    (@extract_type enum $name:ident $($rest:tt)*) => ($name);
-
-    () => ();
-    (
-        $(#[$attr:meta])*
-        struct $name:ident<'a> {
-            $($fields:tt)*
-        }
-        $($rest:tt)*
-    ) => (
-        __ast_struct! {
-            @launch_pad
-            $(#[$attr])*
-            $name
-            [ 'a ]
-            [ ]
-            { $($fields)* }
-        }
-        ast_types!($($rest)*);
-    );
-    (
-        $(#[$attr:meta])*
-        struct $name:ident<$($generics:ident),+> where [$($bounds:tt)+] {
-            $($fields:tt)*
-        }
-        $($rest:tt)*
-    ) => (
-        __ast_struct! {
-            @launch_pad
-            $(#[$attr])*
-            $name
-            [$($generics)+]
-            [$($bounds)+]
-            { $($fields)* }
-        }
-        ast_types!($($rest)*);
-    );
-    (
-        $(#[$attr:meta])*
-        struct $name:ident {
-            $($fields:tt)*
-        }
-        $($rest:tt)*
-    ) => (
-        __ast_struct! {
-            @launch_pad
-            $(#[$attr])*
-            $name
-            [ ]
-            [ ]
-            { $($fields)* }
-        }
-        ast_types!($($rest)*);
-    );
-
-    (
-        $(#[$attr:meta])*
-        struct $name:ident<'a> (
-            $($fields:tt)*
-        )
-        $($rest:tt)*
-    ) => (
-        __ast_tuple_struct! {
-            @launch_pad
-            $(#[$attr])*
-            $name
-            [ 'a ]
-            ( $($fields)* )
-        }
-        ast_types!($($rest)*);
-    );
-    (
-        $(#[$attr:meta])*
-        struct $name:ident (
-            $($fields:tt)*
-        )
-        $($rest:tt)*
-    ) => (
-        __ast_tuple_struct! {
-            @launch_pad
-            $(#[$attr])*
-            $name
-            [ ]
-            ( $($fields)* )
-        }
-        ast_types!($($rest)*);
-    );
-
-    (
-        $(#[$attr:meta])*
-        enum $name:ident<'a> {
-            $($variants:tt)*
-        }
-        $($rest:tt)*
-    ) => (
-        __ast_enum! {
-            @launch_pad
-            $(#[$attr])*
-            $name
-            [ 'a ]
-            { $($variants)* }
-        }
-        ast_types!($($rest)*);
-    );
-    (
-        $(#[$attr:meta])*
-        enum $name:ident {
-            $($variants:tt)*
-        }
-        $($rest:tt)*
-    ) => (
-        __ast_enum! {
-            @launch_pad
-            $(#[$attr])*
-            $name
-            [ ]
-            { $($variants)* }
-        }
-        ast_types!($($rest)*);
-    );
-}
-
-macro_rules! __ast_tuple_struct {
-    (@launch_pad
-        $(#[$attr:meta])*
-        $name:ident
-        [ $($maybe_a:tt)* ]
-        ( $inner:ty = $submac:ident!( $($args:tt)* ), )
-    ) => (
-        $(#[$attr])*
-        #[derive(Clone, Debug, Eq, PartialEq, Ord, PartialOrd, Hash)]
-        pub struct $name<$($maybe_a)*>(pub $inner);
-
-        impl<'a> $crate::Parse<'a> for $name<$($maybe_a)*> {
-            fn parse(input: &'a str) -> $crate::IResult<&'a str, Self> {
-                use $crate::nom::lib::std::result::Result::*;
-
-                match $submac!(input, $($args)*) {
-                    Err(e) => Err(e),
-                    Ok((i, inner)) => Ok((i, $name(inner))),
-                }
-            }
-        }
-    );
-    (@launch_pad
-        $(#[$attr:meta])*
-        $name:ident
-        [ $($maybe_a:tt)* ]
-        ( $inner:ty, )
-    ) => (
-        __ast_tuple_struct! {
-            @launch_pad
-            $(#[$attr])*
-            $name
-            [ $($maybe_a)* ]
-            ( $inner = weedle!($inner), )
-        }
-    );
-}
-
-macro_rules! __ast_struct {
-    (@build_struct_decl
-        {
-            $(#[$attr:meta])*
-            $name:ident
-            [ $($generics:tt)* ]
-            $($field:ident : $type:ty)*
-        }
-        { }
-    ) => {
-        $(#[$attr])*
-        #[derive(Clone, Debug, Eq, PartialEq, Ord, PartialOrd, Hash)]
-        pub struct $name<$($generics)*> {
-            $(pub $field : $type,)*
-        }
-    };
-    (@build_struct_decl
-        { $($prev:tt)* }
-        { $field:ident : $type:ty, $($rest:tt)* }
-    ) => (
-        __ast_struct! {
-            @build_struct_decl
-            { $($prev)* $field : $type }
-            { $($rest)* }
-        }
-    );
-    (@build_struct_decl
-        { $($prev:tt)* }
-        { $field:ident : $type:ty = $submac:ident!( $($args:tt)* ), $($rest:tt)* }
-    ) => (
-        __ast_struct! {
-            @build_struct_decl
-            { $($prev)* $field : $type }
-            { $($rest)* }
-        }
-    );
-    (@build_struct_decl
-        { $($prev:tt)* }
-        { $field:ident : $type:ty = marker, $($rest:tt)* }
-    ) => (
-        __ast_struct! {
-            @build_struct_decl
-            { $($prev)* $field : $type }
-            { $($rest)* }
-        }
-    );
-
-    (@build_parser
-        { $i:expr, $($field:ident)* }
-        { }
-    ) => ({
-        use $crate::nom::lib::std::result::Result::Ok;
-        Ok(($i, Self { $($field,)* }))
-    });
-    (@build_parser
-        { $i:expr, $($prev:tt)* }
-        { $field:ident : $type:ty = $submac:ident!( $($args:tt)* ), $($rest:tt)* }
-    ) => ({
-        use $crate::nom::lib::std::result::Result::*;
-
-        match $submac!($i, $($args)*) {
-            Err(e) => Err(e),
-            Ok((i, $field)) => {
-                __ast_struct! {
-                    @build_parser
-                    { i, $($prev)* $field }
-                    { $($rest)* }
-                }
-            },
-        }
-    });
-    (@build_parser
-        { $($prev:tt)* }
-        { $field:ident : $type:ty = marker, $($rest:tt)* }
-    ) => ({
-        let $field = ::std::default::Default::default();
-        __ast_struct! {
-            @build_parser
-            { $($prev)* $field }
-            { $($rest)* }
-        }
-    });
-    (@build_parser
-        { $($prev:tt)* }
-        { $field:ident : $type:ty, $($rest:tt)* }
-    ) => (
-        __ast_struct! {
-            @build_parser
-            { $($prev)* }
-            { $field : $type = weedle!($type), $($rest)* }
-        }
-    );
-
-    (
-        @launch_pad
-        $(#[$attr:meta])*
-        $name:ident
-        [ ]
-        [ ]
-        { $($fields:tt)* }
-    ) => {
-        __ast_struct! {
-            @build_struct_decl
-            {
-                $(#[$attr])*
-                $name
-                [ ]
-            }
-            { $($fields)* }
-        }
-
-        impl<'a> $crate::Parse<'a> for $name {
-            fn parse(input: &'a str) -> $crate::IResult<&'a str, Self> {
-                __ast_struct! {
-                    @build_parser
-                    { input, }
-                    { $($fields)* }
-                }
-            }
-        }
-    };
-    (
-        @launch_pad
-        $(#[$attr:meta])*
-        $name:ident
-        [ 'a ]
-        [ ]
-        { $($fields:tt)* }
-    ) => {
-        __ast_struct! {
-            @build_struct_decl
-            {
-                $(#[$attr])*
-                $name
-                [ 'a ]
-            }
-            { $($fields)* }
-        }
-
-        impl<'a> $crate::Parse<'a> for $name<'a> {
-            fn parse(input: &'a str) -> $crate::IResult<&'a str, Self> {
-                __ast_struct! {
-                    @build_parser
-                    { input, }
-                    { $($fields)* }
-                }
-            }
-        }
-    };
-    (
-        @launch_pad
-        $(#[$attr:meta])*
-        $name:ident
-        [$($generics:ident)+]
-        [$($bounds:tt)+]
-        { $($fields:tt)* }
-    ) => {
-        __ast_struct! {
-            @build_struct_decl
-            {
-                $(#[$attr])*
-                $name
-                [$($generics),+]
-            }
-            { $($fields)* }
-        }
-
-        impl<'a, $($generics),+> $crate::Parse<'a> for $name<$($generics),+> where $($bounds)+ {
-            fn parse(input: &'a str) -> $crate::IResult<&'a str, Self> {
-                __ast_struct! {
-                    @build_parser
-                    { input, }
-                    { $($fields)* }
-                }
-            }
-        }
-    };
-}
-
-macro_rules! __ast_enum {
-    (@build_enum_decl
-        {
-            $(#[$attr:meta])*
-            $name:ident
-            [ $($maybe_a:tt)* ]
-            $($variant:ident($member:ty))*
-        }
-        { }
-    ) => (
-        $(#[$attr])*
-        #[derive(Clone, Debug, Eq, PartialEq, Ord, PartialOrd, Hash)]
-        pub enum $name<$($maybe_a)*> {
-            $($variant($member),)*
-        }
-    );
-    (@build_enum_decl
-        { $($prev:tt)* }
-        { $variant:ident($member:ty), $($rest:tt)* }
-    ) => (
-        __ast_enum! {
-            @build_enum_decl
-            { $($prev)* $variant($member) }
-            { $($rest)* }
-        }
-    );
-    (@build_enum_decl
-        { $($prev:tt)* }
-        { $(#[$attr:meta])* $variant:ident( $($member:tt)* ), $($rest:tt)* }
-    ) => (
-        __ast_enum! {
-            @build_enum_decl
-            { $($prev)* $variant(ast_types! { @extract_type $($member)* }) }
-            { $($rest)* }
-        }
-    );
-
-    (@build_sub_types { }) => ();
-    (@build_sub_types
-        { $variant:ident($member:ty), $($rest:tt)* }
-    ) => (
-        __ast_enum! {
-            @build_sub_types
-            { $($rest)* }
-        }
-    );
-    (@build_sub_types
-        { $(#[$attr:meta])* $variant:ident( $($member:tt)* ), $($rest:tt)* }
-    ) => (
-        ast_types! {
-            $(#[$attr])*
-            $($member)*
-        }
-        __ast_enum! {
-            @build_sub_types
-            { $($rest)* }
-        }
-    );
-
-
-    (@build_conversions $name:ident [ $($maybe_a:tt)* ] { }) => ();
-    (@build_conversions
-        $name:ident
-        [ $($maybe_a:tt)* ]
-        { $variant:ident($member:ty), $($rest:tt)* }
-    ) => (
-        impl<$($maybe_a)*> From<$member> for $name<$($maybe_a)*> {
-            fn from(x: $member) -> Self {
-                $name::$variant(x)
-            }
-        }
-        __ast_enum! {
-            @build_conversions
-            $name
-            [ $($maybe_a)* ]
-            { $($rest)* }
-        }
-    );
-    (@build_conversions
-        $name:ident
-        [ $($maybe_a:tt)* ]
-        { $(#[$attr:meta])* $variant:ident( $($member:tt)* ), $($rest:tt)* }
-    ) => (
-        __ast_enum! {
-            @build_conversions
-            $name
-            [ $($maybe_a)* ]
-            { $variant(ast_types! { @extract_type $($member)* }), $($rest)* }
-        }
-    );
-
-    (@build_parse
-        { $name:ident [ $($maybe_a:tt)* ] $($member:ty)* }
-        { }
-    ) => (
-        impl<'a> $crate::Parse<'a> for $name<$($maybe_a)*> {
-            parser!(alt!(
-                $(weedle!($member) => {From::from})|*
-            ));
-        }
-    );
-    (@build_parse
-        { $($prev:tt)* }
-        { $variant:ident($member:ty), $($rest:tt)* }
-    ) => (
-        __ast_enum! {
-            @build_parse
-            { $($prev)* $member }
-            { $($rest)* }
-        }
-    );
-    (@build_parse
-        { $($prev:tt)* }
-        { $(#[$attr:meta])* $variant:ident( $($member:tt)* ), $($rest:tt)* }
-    ) => (
-        __ast_enum! {
-            @build_parse
-            { $($prev)* ast_types! { @extract_type $($member)* } }
-            { $($rest)* }
-        }
-    );
-
-    (@launch_pad
-        $(#[$attr:meta])*
-        $name:ident
-        [ $($maybe_a:tt)* ]
-        { $($variants:tt)* }
-    ) => (
-        __ast_enum! {
-            @build_enum_decl
-            { $(#[$attr])* $name [ $($maybe_a)* ] }
-            { $($variants)* }
-        }
-
-        __ast_enum! {
-            @build_sub_types
-            { $($variants)* }
-        }
-
-        __ast_enum! {
-            @build_conversions
-            $name
-            [ $($maybe_a)* ]
-            { $($variants)* }
-        }
-
-        __ast_enum! {
-            @build_parse
-            { $name [ $($maybe_a)* ] }
-            { $($variants)* }
-        }
-    );
-}
-
-#[cfg(test)]
-macro_rules! test {
-    (@arg $parsed:ident) => {};
-    (@arg $parsed:ident $($lhs:tt).+ == $rhs:expr; $($rest:tt)*) => {
-        assert_eq!($parsed.$($lhs).+, $rhs);
-        test!(@arg $parsed $($rest)*);
-    };
-    (@arg $parsed:ident $($lhs:tt).+(); $($rest:tt)*) => {
-        assert!($parsed.$($lhs).+());
-        test!(@arg $parsed $($rest)*);
-    };
-    (@arg $parsed:ident $($lhs:tt).+() == $rhs:expr; $($rest:tt)*) => {
-        assert_eq!($parsed.$($lhs).+(), $rhs);
-        test!(@arg $parsed $($rest)*);
-    };
-    (err $name:ident { $raw:expr => $typ:ty }) => {
-        #[test]
-        fn $name() {
-            <$typ>::parse($raw).unwrap_err();
-        }
-    };
-    ($name:ident { $raw:expr => $rem:expr; $typ:ty => $val:expr }) => {
-        #[test]
-        fn $name() {
-            let (rem, parsed) = <$typ>::parse($raw).unwrap();
-            assert_eq!(rem, $rem);
-            assert_eq!(parsed, $val);
-        }
-    };
-    ($name:ident { $raw:expr => $rem:expr; $typ:ty; $($body:tt)* }) => {
-        #[test]
-        fn $name() {
-            let (_rem, _parsed) = <$typ>::parse($raw).unwrap();
-            assert_eq!(_rem, $rem);
-            test!(@arg _parsed $($body)*);
-        }
-    };
-}
-
-#[cfg(test)]
-macro_rules! test_variants {
-    ($struct_:ident { $( $variant:ident == $value:expr ),* $(,)* }) => {
-        #[allow(non_snake_case)]
-        mod $struct_ {
-            $(
-                mod $variant {
-                    use $crate::types::*;
-                    #[test]
-                    fn should_parse() {
-                        let (rem, parsed) = $struct_::parse($value).unwrap();
-                        assert_eq!(rem, "");
-                        match parsed {
-                            $struct_::$variant(_) => {},
-                            _ => { panic!("Failed to parse"); }
-                        }
-                    }
-                }
-            )*
-        }
-    };
-}
diff --git a/third_party/rust/weedle/src/mixin.rs b/third_party/rust/weedle/src/mixin.rs
deleted file mode 100644
index dcb40d50c5..0000000000
--- a/third_party/rust/weedle/src/mixin.rs
+++ /dev/null
@@ -1,60 +0,0 @@
-use crate::argument::ArgumentList;
-use crate::attribute::ExtendedAttributeList;
-use crate::common::{Identifier, Parenthesized};
-use crate::interface::{ConstMember, StringifierMember};
-use crate::types::{AttributedType, ReturnType};
-
-/// Parses the members declarations of a mixin
-pub type MixinMembers<'a> = Vec<MixinMember<'a>>;
-
-ast_types! {
-    /// Parses one of the variants of a mixin member
-    enum MixinMember<'a> {
-        Const(ConstMember<'a>),
-        /// Parses `[attributes]? stringifier? returntype identifier? (( args ));`
-        ///
-        /// (( )) means ( ) chars
-        Operation(struct OperationMixinMember<'a> {
-            attributes: Option<ExtendedAttributeList<'a>>,
-            stringifier: Option<term!(stringifier)>,
-            return_type: ReturnType<'a>,
-            identifier: Option<Identifier<'a>>,
-            args: Parenthesized<ArgumentList<'a>>,
-            semi_colon: term!(;),
-        }),
-        /// Parses `[attributes]? stringifier? readonly? attribute attributedtype identifier;`
-        Attribute(struct AttributeMixinMember<'a> {
-            attributes: Option<ExtendedAttributeList<'a>>,
-            stringifier: Option<term!(stringifier)>,
-            readonly: Option<term!(readonly)>,
-            attribute: term!(attribute),
-            type_: AttributedType<'a>,
-            identifier: Identifier<'a>,
-            semi_colon: term!(;),
-        }),
-        Stringifier(StringifierMember<'a>),
-    }
-}
-
-#[cfg(test)]
-mod test {
-    use super::*;
-    use crate::Parse;
-
-    test!(should_parse_attribute_mixin_member { "stringifier readonly attribute short name;" =>
-        "";
-        AttributeMixinMember;
-        attributes.is_none();
-        stringifier.is_some();
-        readonly.is_some();
-        identifier.0 == "name";
-    });
-
-    test!(should_parse_operation_mixin_member { "short fnName(long a);" =>
-        "";
-        OperationMixinMember;
-        attributes.is_none();
-        stringifier.is_none();
-        identifier.is_some();
-    });
-}
diff --git a/third_party/rust/weedle/src/namespace.rs b/third_party/rust/weedle/src/namespace.rs
deleted file mode 100644
index ed28573218..0000000000
--- a/third_party/rust/weedle/src/namespace.rs
+++ /dev/null
@@ -1,52 +0,0 @@
-use crate::argument::ArgumentList;
-use crate::attribute::ExtendedAttributeList;
-use crate::common::{Identifier, Parenthesized};
-use crate::types::{AttributedType, ReturnType};
-
-/// Parses namespace members declaration
-pub type NamespaceMembers<'a> = Vec<NamespaceMember<'a>>;
-
-ast_types! {
-    /// Parses namespace member declaration
-    enum NamespaceMember<'a> {
-        /// Parses `[attributes]? returntype identifier? (( args ));`
-        ///
-        /// (( )) means ( ) chars
-        Operation(struct OperationNamespaceMember<'a> {
-            attributes: Option<ExtendedAttributeList<'a>>,
-            return_type: ReturnType<'a>,
-            identifier: Option<Identifier<'a>>,
-            args: Parenthesized<ArgumentList<'a>>,
-            semi_colon: term!(;),
-        }),
-        /// Parses `[attribute]? readonly attributetype type identifier;`
-        Attribute(struct AttributeNamespaceMember<'a> {
-            attributes: Option<ExtendedAttributeList<'a>>,
-            readonly: term!(readonly),
-            attribute: term!(attribute),
-            type_: AttributedType<'a>,
-            identifier: Identifier<'a>,
-            semi_colon: term!(;),
-        }),
-    }
-}
-
-#[cfg(test)]
-mod test {
-    use super::*;
-    use crate::Parse;
-
-    test!(should_parse_attribute_namespace_member { "readonly attribute short name;" =>
-        "";
-        AttributeNamespaceMember;
-        attributes.is_none();
-        identifier.0 == "name";
-    });
-
-    test!(should_parse_operation_namespace_member { "short (long a, long b);" =>
-        "";
-        OperationNamespaceMember;
-        attributes.is_none();
-        identifier.is_none();
-    });
-}
diff --git a/third_party/rust/weedle/src/term.rs b/third_party/rust/weedle/src/term.rs
deleted file mode 100644
index 008a538f0e..0000000000
--- a/third_party/rust/weedle/src/term.rs
+++ /dev/null
@@ -1,690 +0,0 @@
-macro_rules! generate_terms {
-    ($( $(#[$attr:meta])* $typ:ident => $tok:expr ),*) => {
-        $(
-            $(#[$attr])*
-            #[derive(Clone, Copy, Debug, Default, Eq, Hash, Ord, PartialEq, PartialOrd)]
-            pub struct $typ;
-
-            impl<'a> $crate::Parse<'a> for $typ {
-                parser!(do_parse!(
-                    ws!(tag!($tok)) >>
-                    ($typ)
-                ));
-            }
-        )*
-    };
-}
-
-macro_rules! ident_tag (
-    ($i:expr, $tok:expr) => (
-        {
-            match tag!($i, $tok) {
-                Err(e) => Err(e),
-                Ok((i, o)) => {
-                    use nom::{character::is_alphanumeric, Err as NomErr, error::ErrorKind};
-                    let mut res = Ok((i, o));
-                    if let Some(&c) = i.as_bytes().first() {
-                        if is_alphanumeric(c) || c == b'_' || c == b'-' {
-                            res = Err(NomErr::Error(($i, ErrorKind::Tag)));
-                        }
-                    }
-                    res
-                },
-            }
-        }
-    )
-);
-
-macro_rules! generate_terms_for_names {
-    ($( $(#[$attr:meta])* $typ:ident => $tok:expr,)*) => {
-        $(
-            $(#[$attr])*
-            #[derive(Clone, Copy, Debug, Default, Eq, Hash, Ord, PartialEq, PartialOrd)]
-            pub struct $typ;
-
-            impl<'a> $crate::Parse<'a> for $typ {
-                parser!(do_parse!(
-                    ws!(ident_tag!($tok)) >>
-                    ($typ)
-                ));
-            }
-        )*
-    };
-}
-
-generate_terms! {
-    /// Represents the terminal symbol `(`
-    OpenParen => "(",
-
-    /// Represents the terminal symbol `)`
-    CloseParen => ")",
-
-    /// Represents the terminal symbol `[`
-    OpenBracket => "[",
-
-    /// Represents the terminal symbol `]`
-    CloseBracket => "]",
-
-    /// Represents the terminal symbol `{`
-    OpenBrace => "{",
-
-    /// Represents the terminal symbol `}`
-    CloseBrace => "}",
-
-    /// Represents the terminal symbol `,`
-    Comma => ",",
-
-    /// Represents the terminal symbol `-`
-    Minus => "-",
-
-    /// Represents the terminal symbol `.`
-    Dot => ".",
-
-    /// Represents the terminal symbol `...`
-    Ellipsis => "...",
-
-    /// Represents the terminal symbol `:`
-    Colon => ":",
-
-    /// Represents the terminal symbol `;`
-    SemiColon => ";",
-
-    /// Represents the terminal symbol `<`
-    LessThan => "<",
-
-    /// Represents the terminal symbol `=`
-    Assign => "=",
-
-    /// Represents the terminal symbol `>`
-    GreaterThan => ">",
-
-    /// Represents the terminal symbol `?`
-    QMark => "?"
-}
-
-generate_terms_for_names! {
-    /// Represents the terminal symbol `or`
-    Or => "or",
-
-    /// Represents the terminal symbol `optional`
-    Optional => "optional",
-
-    /// Represents the terminal symbol `attribute`
-    Attribute => "attribute",
-
-    /// Represents the terminal symbol `callback`
-    Callback => "callback",
-
-    /// Represents the terminal symbol `const`
-    Const => "const",
-
-    /// Represents the terminal symbol `deleter`
-    Deleter => "deleter",
-
-    /// Represents the terminal symbol `dictionary`
-    Dictionary => "dictionary",
-
-    /// Represents the terminal symbol `enum`
-    Enum => "enum",
-
-    /// Represents the terminal symbol `getter`
-    Getter => "getter",
-
-    /// Represents the terminal symbol `includes`
-    Includes => "includes",
-
-    /// Represents the terminal symbol `inherit`
-    Inherit => "inherit",
-
-    /// Represents the terminal symbol `interface`
-    Interface => "interface",
-
-    /// Represents the terminal symbol `iterable`
-    Iterable => "iterable",
-
-    /// Represents the terminal symbol `maplike`
-    Maplike => "maplike",
-
-    /// Represents the terminal symbol `namespace`
-    Namespace => "namespace",
-
-    /// Represents the terminal symbol `partial`
-    Partial => "partial",
-
-    /// Represents the terminal symbol `required`
-    Required => "required",
-
-    /// Represents the terminal symbol `setlike`
-    Setlike => "setlike",
-
-    /// Represents the terminal symbol `setter`
-    Setter => "setter",
-
-    /// Represents the terminal symbol `static`
-    Static => "static",
-
-    /// Represents the terminal symbol `stringifier`
-    Stringifier => "stringifier",
-
-    /// Represents the terminal symbol `typedef`
-    Typedef => "typedef",
-
-    /// Represents the terminal symbol `unrestricted`
-    Unrestricted => "unrestricted",
-
-    /// Represents the terminal symbol `symbol`
-    Symbol => "symbol",
-
-    /// Represents the terminal symbol `Infinity`
-    NegInfinity => "-Infinity",
-
-    /// Represents the terminal symbol `ByteString`
-    ByteString => "ByteString",
-
-    /// Represents the terminal symbol `DOMString`
-    DOMString => "DOMString",
-
-    /// Represents the terminal symbol `FrozenArray`
-    FrozenArray => "FrozenArray",
-
-    /// Represents the terminal symbol `Infinity`
-    Infinity => "Infinity",
-
-    /// Represents the terminal symbol `NaN`
-    NaN => "NaN",
-
-    /// Represents the terminal symbol `USVString`
-    USVString => "USVString",
-
-    /// Represents the terminal symbol `any`
-    Any => "any",
-
-    /// Represents the terminal symbol `boolean`
-    Boolean => "boolean",
-
-    /// Represents the terminal symbol `byte`
-    Byte => "byte",
-
-    /// Represents the terminal symbol `double`
-    Double => "double",
-
-    /// Represents the terminal symbol `false`
-    False => "false",
-
-    /// Represents the terminal symbol `float`
-    Float => "float",
-
-    /// Represents the terminal symbol `long`
-    Long => "long",
-
-    /// Represents the terminal symbol `null`
-    Null => "null",
-
-    /// Represents the terminal symbol `object`
-    Object => "object",
-
-    /// Represents the terminal symbol `octet`
-    Octet => "octet",
-
-    /// Represents the terminal symbol `sequence`
-    Sequence => "sequence",
-
-    /// Represents the terminal symbol `short`
-    Short => "short",
-
-    /// Represents the terminal symbol `true`
-    True => "true",
-
-    /// Represents the terminal symbol `unsigned`
-    Unsigned => "unsigned",
-
-    /// Represents the terminal symbol `void`
-    Void => "void",
-
-    /// Represents the terminal symbol `record`
-    Record => "record",
-
-    /// Represents the terminal symbol `ArrayBuffer`
-    ArrayBuffer => "ArrayBuffer",
-
-    /// Represents the terminal symbol `DataView`
-    DataView => "DataView",
-
-    /// Represents the terminal symbol `Int8Array`
-    Int8Array => "Int8Array",
-
-    /// Represents the terminal symbol `Int16Array`
-    Int16Array => "Int16Array",
-
-    /// Represents the terminal symbol `Int32Array`
-    Int32Array => "Int32Array",
-
-    /// Represents the terminal symbol `Uint8Array`
-    Uint8Array => "Uint8Array",
-
-    /// Represents the terminal symbol `Uint16Array`
-    Uint16Array => "Uint16Array",
-
-    /// Represents the terminal symbol `Uint32Array`
-    Uint32Array => "Uint32Array",
-
-    /// Represents the terminal symbol `Uint8ClampedArray`
-    Uint8ClampedArray => "Uint8ClampedArray",
-
-    /// Represents the terminal symbol `Float32Array`
-    Float32Array => "Float32Array",
-
-    /// Represents the terminal symbol `Float64Array`
-    Float64Array => "Float64Array",
-
-    /// Represents the terminal symbol `ArrayBufferView`
-    ArrayBufferView => "ArrayBufferView",
-
-    /// Represents the terminal symbol `BufferSource
-    BufferSource => "BufferSource",
-
-    /// Represents the terminal symbol `Promise`
-    Promise => "Promise",
-
-    /// Represents the terminal symbol `Error`
-    Error => "Error",
-
-    /// Represents the terminal symbol `readonly`
-    ReadOnly => "readonly",
-
-    /// Represents the terminal symbol `mixin`
-    Mixin => "mixin",
-
-    /// Represents the terminal symbol `implements`
-    Implements => "implements",
-
-    /// Represents the terminal symbol `legacycaller`
-    LegacyCaller => "legacycaller",
-
-    /// Represents the terminal symbol `constructor`
-    Constructor => "constructor",
-}
-
-#[macro_export]
-macro_rules! term {
-    (OpenParen) => {
-        $crate::term::OpenParen
-    };
-    (CloseParen) => {
-        $crate::term::CloseParen
-    };
-    (OpenBracket) => {
-        $crate::term::OpenBracket
-    };
-    (CloseBracket) => {
-        $crate::term::CloseBracket
-    };
-    (OpenBrace) => {
-        $crate::term::OpenBrace
-    };
-    (CloseBrace) => {
-        $crate::term::CloseBrace
-    };
-    (,) => {
-        $crate::term::Comma
-    };
-    (-) => {
-        $crate::term::Minus
-    };
-    (.) => {
-        $crate::term::Dot
-    };
-    (...) => {
-        $crate::term::Ellipsis
-    };
-    (:) => {
-        $crate::term::Colon
-    };
-    (;) => {
-        $crate::term::SemiColon
-    };
-    (<) => {
-        $crate::term::LessThan
-    };
-    (=) => {
-        $crate::term::Assign
-    };
-    (>) => {
-        $crate::term::GreaterThan
-    };
-    (?) => {
-        $crate::term::QMark
-    };
-    (or) => {
-        $crate::term::Or
-    };
-    (optional) => {
-        $crate::term::Optional
-    };
-    (attribute) => {
-        $crate::term::Attribute
-    };
-    (callback) => {
-        $crate::term::Callback
-    };
-    (const) => {
-        $crate::term::Const
-    };
-    (deleter) => {
-        $crate::term::Deleter
-    };
-    (dictionary) => {
-        $crate::term::Dictionary
-    };
-    (enum) => {
-        $crate::term::Enum
-    };
-    (getter) => {
-        $crate::term::Getter
-    };
-    (includes) => {
-        $crate::term::Includes
-    };
-    (inherit) => {
-        $crate::term::Inherit
-    };
-    (interface) => {
-        $crate::term::Interface
-    };
-    (iterable) => {
-        $crate::term::Iterable
-    };
-    (maplike) => {
-        $crate::term::Maplike
-    };
-    (namespace) => {
-        $crate::term::Namespace
-    };
-    (partial) => {
-        $crate::term::Partial
-    };
-    (required) => {
-        $crate::term::Required
-    };
-    (setlike) => {
-        $crate::term::Setlike
-    };
-    (setter) => {
-        $crate::term::Setter
-    };
-    (static) => {
-        $crate::term::Static
-    };
-    (stringifier) => {
-        $crate::term::Stringifier
-    };
-    (typedef) => {
-        $crate::term::Typedef
-    };
-    (unrestricted) => {
-        $crate::term::Unrestricted
-    };
-    (symbol) => {
-        $crate::term::Symbol
-    };
-    (- Infinity) => {
-        $crate::term::NegInfinity
-    };
-    (ByteString) => {
-        $crate::term::ByteString
-    };
-    (DOMString) => {
-        $crate::term::DOMString
-    };
-    (FrozenArray) => {
-        $crate::term::FrozenArray
-    };
-    (Infinity) => {
-        $crate::term::Infinity
-    };
-    (NaN) => {
-        $crate::term::NaN
-    };
-    (USVString) => {
-        $crate::term::USVString
-    };
-    (any) => {
-        $crate::term::Any
-    };
-    (boolean) => {
-        $crate::term::Boolean
-    };
-    (byte) => {
-        $crate::term::Byte
-    };
-    (double) => {
-        $crate::term::Double
-    };
-    (false) => {
-        $crate::term::False
-    };
-    (float) => {
-        $crate::term::Float
-    };
-    (long) => {
-        $crate::term::Long
-    };
-    (null) => {
-        $crate::term::Null
-    };
-    (object) => {
-        $crate::term::Object
-    };
-    (octet) => {
-        $crate::term::Octet
-    };
-    (sequence) => {
-        $crate::term::Sequence
-    };
-    (short) => {
-        $crate::term::Short
-    };
-    (true) => {
-        $crate::term::True
-    };
-    (unsigned) => {
-        $crate::term::Unsigned
-    };
-    (void) => {
-        $crate::term::Void
-    };
-    (record) => {
-        $crate::term::Record
-    };
-    (ArrayBuffer) => {
-        $crate::term::ArrayBuffer
-    };
-    (DataView) => {
-        $crate::term::DataView
-    };
-    (Int8Array) => {
-        $crate::term::Int8Array
-    };
-    (Int16Array) => {
-        $crate::term::Int16Array
-    };
-    (Int32Array) => {
-        $crate::term::Int32Array
-    };
-    (Uint8Array) => {
-        $crate::term::Uint8Array
-    };
-    (Uint16Array) => {
-        $crate::term::Uint16Array
-    };
-    (Uint32Array) => {
-        $crate::term::Uint32Array
-    };
-    (Uint8ClampedArray) => {
-        $crate::term::Uint8ClampedArray
-    };
-    (Float32Array) => {
-        $crate::term::Float32Array
-    };
-    (Float64Array) => {
-        $crate::term::Float64Array
-    };
-    (ArrayBufferView) => {
-        $crate::term::ArrayBufferView
-    };
-    (BufferSource) => {
-        $crate::term::BufferSource
-    };
-    (Promise) => {
-        $crate::term::Promise
-    };
-    (Error) => {
-        $crate::term::Error
-    };
-    (readonly) => {
-        $crate::term::ReadOnly
-    };
-    (mixin) => {
-        $crate::term::Mixin
-    };
-    (implements) => {
-        $crate::term::Implements
-    };
-    (legacycaller) => {
-        $crate::term::LegacyCaller
-    };
-    (constructor) => {
-        $crate::term::Constructor
-    };
-}
-
-#[cfg(test)]
-mod test {
-    macro_rules! generate_tests {
-        ($($m:ident, $typ:ident, $string:expr;)*) => {
-            $(
-                mod $m {
-                    use super::super::$typ;
-                    use crate::Parse;
-
-                    #[test]
-                    fn should_parse() {
-                        let (rem, parsed) = $typ::parse(concat!($string)).unwrap();
-                        assert_eq!(rem, "");
-                        assert_eq!(parsed, $typ);
-                    }
-
-                    #[test]
-                    fn should_parse_with_preceding_spaces() {
-                        let (rem, parsed) = $typ::parse(concat!("  ", $string)).unwrap();
-                        assert_eq!(rem, "");
-                        assert_eq!(parsed, $typ);
-                    }
-
-                    #[test]
-                    fn should_parse_with_succeeding_spaces() {
-                        let (rem, parsed) = $typ::parse(concat!($string, "  ")).unwrap();
-                        assert_eq!(rem, "");
-                        assert_eq!(parsed, $typ);
-                    }
-
-                    #[test]
-                    fn should_parse_with_surrounding_spaces() {
-                        let (rem, parsed) = $typ::parse(concat!("  ", $string, "  ")).unwrap();
-                        assert_eq!(rem, "");
-                        assert_eq!(parsed, $typ);
-                    }
-
-                    #[test]
-                    fn should_parse_if_anything_next() {
-                        let (rem, parsed) = $typ::parse(concat!($string, "  anything")).unwrap();
-                        assert_eq!(rem, "anything");
-                        assert_eq!(parsed, $typ);
-                    }
-                }
-            )*
-        };
-    }
-
-    generate_tests![
-        openparen, OpenParen, "(";
-        closeparen, CloseParen, ")";
-        openbracket, OpenBracket, "[";
-        closebracket, CloseBracket, "]";
-        openbrace, OpenBrace, "{";
-        closebrace, CloseBrace, "}";
-        comma, Comma, ",";
-        minus, Minus, "-";
-        dot, Dot, ".";
-        ellipsis, Ellipsis, "...";
-        colon, Colon, ":";
-        semicolon, SemiColon, ";";
-        lessthan, LessThan, "<";
-        assign, Assign, "=";
-        greaterthan, GreaterThan, ">";
-        qmark, QMark, "?";
-        or, Or, "or";
-        optional, Optional, "optional";
-        attribute, Attribute, "attribute";
-        callback, Callback, "callback";
-        const_, Const, "const";
-        deleter, Deleter, "deleter";
-        dictionary, Dictionary, "dictionary";
-        enum_, Enum, "enum";
-        getter, Getter, "getter";
-        includes, Includes, "includes";
-        inherit, Inherit, "inherit";
-        interface, Interface, "interface";
-        iterable, Iterable, "iterable";
-        maplike, Maplike, "maplike";
-        namespace, Namespace, "namespace";
-        partial, Partial, "partial";
-        required, Required, "required";
-        setlike, Setlike, "setlike";
-        setter, Setter, "setter";
-        static_, Static, "static";
-        stringifier, Stringifier, "stringifier";
-        typedef, Typedef, "typedef";
-        unrestricted, Unrestricted, "unrestricted";
-        symbol, Symbol, "symbol";
-        neginfinity, NegInfinity, "-Infinity";
-        bytestring, ByteString, "ByteString";
-        domstring, DOMString, "DOMString";
-        frozenarray, FrozenArray, "FrozenArray";
-        infinity, Infinity, "Infinity";
-        nan, NaN, "NaN";
-        usvstring, USVString, "USVString";
-        any, Any, "any";
-        boolean, Boolean, "boolean";
-        byte, Byte, "byte";
-        double, Double, "double";
-        false_, False, "false";
-        float, Float, "float";
-        long, Long, "long";
-        null, Null, "null";
-        object, Object, "object";
-        octet, Octet, "octet";
-        sequence, Sequence, "sequence";
-        short, Short, "short";
-        true_, True, "true";
-        unsigned, Unsigned, "unsigned";
-        void, Void, "void";
-        record, Record, "record";
-        arraybuffer, ArrayBuffer, "ArrayBuffer";
-        dataview, DataView, "DataView";
-        int8array, Int8Array, "Int8Array";
-        int16array, Int16Array, "Int16Array";
-        int32array, Int32Array, "Int32Array";
-        uint8array, Uint8Array, "Uint8Array";
-        uint16array, Uint16Array, "Uint16Array";
-        uint32array, Uint32Array, "Uint32Array";
-        uint8clampedarray, Uint8ClampedArray, "Uint8ClampedArray";
-        float32array, Float32Array, "Float32Array";
-        float64array, Float64Array, "Float64Array";
-        promise, Promise, "Promise";
-        error, Error, "Error";
-        implements, Implements, "implements";
-        legacycaller, LegacyCaller, "legacycaller";
-        constructor, Constructor, "constructor";
-    ];
-}
diff --git a/third_party/rust/weedle/src/types.rs b/third_party/rust/weedle/src/types.rs
deleted file mode 100644
index 8ee7e176f9..0000000000
--- a/third_party/rust/weedle/src/types.rs
+++ /dev/null
@@ -1,380 +0,0 @@
-use crate::attribute::ExtendedAttributeList;
-use crate::common::{Generics, Identifier, Parenthesized, Punctuated};
-use crate::term;
-use crate::Parse;
-
-/// Parses a union of types
-pub type UnionType<'a> = Parenthesized<Punctuated<UnionMemberType<'a>, term!(or)>>;
-
-ast_types! {
-    /// Parses either single type or a union type
-    enum Type<'a> {
-        /// Parses one of the single types
-        Single(enum SingleType<'a> {
-            Any(term!(any)),
-            NonAny(NonAnyType<'a>),
-        }),
-        Union(MayBeNull<UnionType<'a>>),
-    }
-
-    // Parses any single non-any type
-    enum NonAnyType<'a> {
-        Promise(PromiseType<'a>),
-        Integer(MayBeNull<IntegerType>),
-        FloatingPoint(MayBeNull<FloatingPointType>),
-        Boolean(MayBeNull<term!(boolean)>),
-        Byte(MayBeNull<term!(byte)>),
-        Octet(MayBeNull<term!(octet)>),
-        ByteString(MayBeNull<term!(ByteString)>),
-        DOMString(MayBeNull<term!(DOMString)>),
-        USVString(MayBeNull<term!(USVString)>),
-        Sequence(MayBeNull<SequenceType<'a>>),
-        Object(MayBeNull<term!(object)>),
-        Symbol(MayBeNull<term!(symbol)>),
-        Error(MayBeNull<term!(Error)>),
-        ArrayBuffer(MayBeNull<term!(ArrayBuffer)>),
-        DataView(MayBeNull<term!(DataView)>),
-        Int8Array(MayBeNull<term!(Int8Array)>),
-        Int16Array(MayBeNull<term!(Int16Array)>),
-        Int32Array(MayBeNull<term!(Int32Array)>),
-        Uint8Array(MayBeNull<term!(Uint8Array)>),
-        Uint16Array(MayBeNull<term!(Uint16Array)>),
-        Uint32Array(MayBeNull<term!(Uint32Array)>),
-        Uint8ClampedArray(MayBeNull<term!(Uint8ClampedArray)>),
-        Float32Array(MayBeNull<term!(Float32Array)>),
-        Float64Array(MayBeNull<term!(Float64Array)>),
-        ArrayBufferView(MayBeNull<term!(ArrayBufferView)>),
-        BufferSource(MayBeNull<term!(BufferSource)>),
-        FrozenArrayType(MayBeNull<FrozenArrayType<'a>>),
-        RecordType(MayBeNull<RecordType<'a>>),
-        Identifier(MayBeNull<Identifier<'a>>),
-    }
-
-    /// Parses `sequence<Type>`
-    struct SequenceType<'a> {
-        sequence: term!(sequence),
-        generics: Generics<Box<Type<'a>>>,
-    }
-
-    /// Parses `FrozenArray<Type>`
-    struct FrozenArrayType<'a> {
-        frozen_array: term!(FrozenArray),
-        generics: Generics<Box<Type<'a>>>,
-    }
-
-    /// Parses a nullable type. Ex: `object | object??`
-    ///
-    /// `??` means an actual ? not an optional requirement
-    #[derive(Copy)]
-    struct MayBeNull<T> where [T: Parse<'a>] {
-        type_: T,
-        q_mark: Option<term::QMark>,
-    }
-
-    /// Parses a `Promise<Type|void>` type
-    struct PromiseType<'a> {
-        promise: term!(Promise),
-        generics: Generics<Box<ReturnType<'a>>>,
-    }
-
-    /// Parses `unsigned? short|long|(long long)`
-    #[derive(Copy)]
-    enum IntegerType {
-        /// Parses `unsigned? long long`
-        #[derive(Copy)]
-        LongLong(struct LongLongType {
-            unsigned: Option<term!(unsigned)>,
-            long_long: (term!(long), term!(long)),
-        }),
-        /// Parses `unsigned? long`
-        #[derive(Copy)]
-        Long(struct LongType {
-            unsigned: Option<term!(unsigned)>,
-            long: term!(long),
-        }),
-        /// Parses `unsigned? short`
-        #[derive(Copy)]
-        Short(struct ShortType {
-            unsigned: Option<term!(unsigned)>,
-            short: term!(short),
-        }),
-    }
-
-    /// Parses `unrestricted? float|double`
-    #[derive(Copy)]
-    enum FloatingPointType {
-        /// Parses `unrestricted? float`
-        #[derive(Copy)]
-        Float(struct FloatType {
-            unrestricted: Option<term!(unrestricted)>,
-            float: term!(float),
-        }),
-        /// Parses `unrestricted? double`
-        #[derive(Copy)]
-        Double(struct DoubleType {
-            unrestricted: Option<term!(unrestricted)>,
-            double: term!(double),
-        }),
-    }
-
-    /// Parses `record<StringType, Type>`
-    struct RecordType<'a> {
-        record: term!(record),
-        generics: Generics<(StringType, term!(,), Box<Type<'a>>)>,
-    }
-
-    /// Parses one of the string types `ByteString|DOMString|USVString`
-    #[derive(Copy)]
-    enum StringType {
-        Byte(term!(ByteString)),
-        DOM(term!(DOMString)),
-        USV(term!(USVString)),
-    }
-
-    /// Parses one of the member of a union type
-    enum UnionMemberType<'a> {
-        Single(AttributedNonAnyType<'a>),
-        Union(MayBeNull<UnionType<'a>>),
-    }
-
-    /// Parses a const type
-    enum ConstType<'a> {
-        Integer(MayBeNull<IntegerType>),
-        FloatingPoint(MayBeNull<FloatingPointType>),
-        Boolean(MayBeNull<term!(boolean)>),
-        Byte(MayBeNull<term!(byte)>),
-        Octet(MayBeNull<term!(octet)>),
-        Identifier(MayBeNull<Identifier<'a>>),
-    }
-
-    /// Parses the return type which may be `void` or any given Type
-    enum ReturnType<'a> {
-        Void(term!(void)),
-        Type(Type<'a>),
-    }
-
-    /// Parses `[attributes]? type`
-    struct AttributedType<'a> {
-        attributes: Option<ExtendedAttributeList<'a>>,
-        type_: Type<'a>,
-    }
-
-    /// Parses `[attributes]? type` where the type is a single non-any type
-    struct AttributedNonAnyType<'a> {
-        attributes: Option<ExtendedAttributeList<'a>>,
-        type_: NonAnyType<'a>,
-    }
-}
-
-#[cfg(test)]
-mod test {
-    use super::*;
-
-    test!(should_parse_may_be_null { "short" =>
-        "";
-        MayBeNull<crate::types::IntegerType>;
-        q_mark.is_none();
-    });
-
-    test!(should_parse_nullable { "short?" =>
-        "";
-        MayBeNull<crate::types::IntegerType>;
-        q_mark.is_some();
-    });
-
-    test_variants!(
-        ReturnType {
-            Void == "void",
-            Type == "any",
-        }
-    );
-
-    test_variants!(
-        ConstType {
-            Integer == "short",
-            FloatingPoint == "float",
-            Boolean == "boolean",
-            Byte == "byte",
-            Octet == "octet",
-            Identifier == "name",
-        }
-    );
-
-    test_variants!(
-        NonAnyType {
-            Promise == "Promise<long>",
-            Integer == "long",
-            FloatingPoint == "float",
-            Boolean == "boolean",
-            Byte == "byte",
-            Octet == "octet",
-            ByteString == "ByteString",
-            DOMString == "DOMString",
-            USVString == "USVString",
-            Sequence == "sequence<short>",
-            Object == "object",
-            Symbol == "symbol",
-            Error == "Error",
-            ArrayBuffer == "ArrayBuffer",
-            DataView == "DataView",
-            Int8Array == "Int8Array",
-            Int16Array == "Int16Array",
-            Int32Array == "Int32Array",
-            Uint8Array == "Uint8Array",
-            Uint16Array == "Uint16Array",
-            Uint32Array == "Uint32Array",
-            Uint8ClampedArray == "Uint8ClampedArray",
-            Float32Array == "Float32Array",
-            Float64Array == "Float64Array",
-            ArrayBufferView == "ArrayBufferView",
-            BufferSource == "BufferSource",
-            FrozenArrayType == "FrozenArray<short>",
-            RecordType == "record<DOMString, short>",
-            Identifier == "mango"
-        }
-    );
-
-    test_variants!(
-        UnionMemberType {
-            Single == "byte",
-            Union == "([Clamp] unsigned long or byte)"
-        }
-    );
-
-    test_variants!(
-        StringType {
-            DOM == "DOMString",
-            USV == "USVString",
-            Byte == "ByteString"
-        }
-    );
-
-    test!(should_parse_record_type { "record<DOMString, short>" =>
-        "";
-        RecordType;
-    });
-
-    test!(should_parse_double_type { "double" =>
-        "";
-        DoubleType;
-    });
-
-    test!(should_parse_float_type { "float" =>
-        "";
-        FloatType;
-    });
-
-    test_variants!(
-        FloatingPointType {
-            Float == "float",
-            Double == "double"
-        }
-    );
-
-    test!(should_parse_long_long_type { "long long" =>
-        "";
-        LongLongType;
-    });
-
-    test!(should_parse_long_type { "long" =>
-        "";
-        LongType;
-    });
-
-    test!(should_parse_short_type { "short" =>
-        "";
-        ShortType;
-    });
-
-    test_variants!(
-        IntegerType {
-            Short == "short",
-            Long == "long",
-            LongLong == "long long"
-        }
-    );
-
-    test!(should_parse_promise_type { "Promise<short>" =>
-        "";
-        PromiseType;
-    });
-
-    test!(should_parse_frozen_array_type { "FrozenArray<short>" =>
-        "";
-        FrozenArrayType;
-    });
-
-    test!(should_parse_sequence_type { "sequence<short>" =>
-        "";
-        SequenceType;
-    });
-
-    test_variants!(
-        SingleType {
-            Any == "any",
-            NonAny == "Promise<short>",
-        }
-    );
-
-    test_variants!(
-        Type {
-            Single == "short",
-            Union == "(short or float)"
-        }
-    );
-
-    test!(should_parse_attributed_type { "[Named] short" =>
-        "";
-        AttributedType;
-        attributes.is_some();
-    });
-
-    test!(should_parse_type_as_identifier { "DOMStringMap" =>
-        // if type is not parsed as identifier, it is parsed as `DOMString` and 'Map' is left
-        "";
-        crate::types::Type;
-    });
-
-    #[test]
-    fn should_parse_union_member_type_attributed_union() {
-        use crate::types::UnionMemberType;
-        let (rem, parsed) = UnionMemberType::parse("([Clamp] byte or [Named] byte)").unwrap();
-        assert_eq!(rem, "");
-        match parsed {
-            UnionMemberType::Union(MayBeNull {
-                type_:
-                    Parenthesized {
-                        body: Punctuated { list, .. },
-                        ..
-                    },
-                ..
-            }) => {
-                assert_eq!(list.len(), 2);
-
-                match list[0] {
-                    UnionMemberType::Single(AttributedNonAnyType { ref attributes, .. }) => {
-                        assert!(attributes.is_some());
-                    }
-
-                    _ => {
-                        panic!("Failed to parse list[0] attributes");
-                    }
-                };
-
-                match list[1] {
-                    UnionMemberType::Single(AttributedNonAnyType { ref attributes, .. }) => {
-                        assert!(attributes.is_some());
-                    }
-
-                    _ => {
-                        panic!("Failed to parse list[1] attributes");
-                    }
-                };
-            }
-
-            _ => {
-                panic!("Failed to parse");
-            }
-        }
-    }
-}
diff --git a/third_party/rust/weedle/src/whitespace.rs b/third_party/rust/weedle/src/whitespace.rs
deleted file mode 100644
index e6bbf0a61f..0000000000
--- a/third_party/rust/weedle/src/whitespace.rs
+++ /dev/null
@@ -1,31 +0,0 @@
-use crate::IResult;
-
-pub(crate) fn sp(input: &str) -> IResult<&str, &str> {
-    recognize!(
-        input,
-        many0!(alt!(
-            // ignores line comments
-            do_parse!(tag!("//") >> take_until!("\n") >> char!('\n') >> (()))
-            |
-            // ignores whitespace
-            map!(take_while1!(|c| c == '\t' || c == '\n' || c == '\r' || c == ' '), |_| ())
-            |
-            // ignores block comments
-            do_parse!(tag!("/*") >> take_until!("*/") >> tag!("*/") >> (()))
-        ))
-    )
-}
-
-/// ws! also ignores line & block comments
-macro_rules! ws (
-    ($i:expr, $($args:tt)*) => ({
-        use $crate::whitespace::sp;
-
-        do_parse!($i,
-            sp >>
-            s: $($args)* >>
-            sp >>
-            (s)
-        )
-    });
-);
diff --git a/third_party/rust/weedle/tests/defs/dom.webidl b/third_party/rust/weedle/tests/defs/dom.webidl
deleted file mode 100644
index 22d436ff5a..0000000000
--- a/third_party/rust/weedle/tests/defs/dom.webidl
+++ /dev/null
@@ -1,549 +0,0 @@
-[Constructor(DOMString type, optional EventInit eventInitDict),
- Exposed=(Window,Worker,AudioWorklet)]
-interface Event {
-  readonly attribute DOMString type;
-  readonly attribute EventTarget? target;
-  readonly attribute EventTarget? srcElement; // historical
-  readonly attribute EventTarget? currentTarget;
-  sequence<EventTarget> composedPath();
-
-  const unsigned short NONE = 0;
-  const unsigned short CAPTURING_PHASE = 1;
-  const unsigned short AT_TARGET = 2;
-  const unsigned short BUBBLING_PHASE = 3;
-  readonly attribute unsigned short eventPhase;
-
-  void stopPropagation();
-           attribute boolean cancelBubble; // historical alias of .stopPropagation
-  void stopImmediatePropagation();
-
-  readonly attribute boolean bubbles;
-  readonly attribute boolean cancelable;
-           attribute boolean returnValue;  // historical
-  void preventDefault();
-  readonly attribute boolean defaultPrevented;
-  readonly attribute boolean composed;
-
-  [Unforgeable] readonly attribute boolean isTrusted;
-  readonly attribute DOMHighResTimeStamp timeStamp;
-
-  void initEvent(DOMString type, optional boolean bubbles = false, optional boolean cancelable = false); // historical
-};
-
-dictionary EventInit {
-  boolean bubbles = false;
-  boolean cancelable = false;
-  boolean composed = false;
-};
-
-[Constructor(DOMString type, optional CustomEventInit eventInitDict),
- Exposed=(Window,Worker)]
-interface CustomEvent : Event {
-  readonly attribute any detail;
-
-  void initCustomEvent(DOMString type, optional boolean bubbles = false, optional boolean cancelable = false, optional any detail = null);
-};
-
-dictionary CustomEventInit : EventInit {
-  any detail = null;
-};
-
-[Constructor,
- Exposed=(Window,Worker,AudioWorklet)]
-interface EventTarget {
-  void addEventListener(DOMString type, EventListener? callback, optional (AddEventListenerOptions or boolean) options);
-  void removeEventListener(DOMString type, EventListener? callback, optional (EventListenerOptions or boolean) options);
-  boolean dispatchEvent(Event event);
-};
-
-callback interface EventListener {
-  void handleEvent(Event event);
-};
-
-dictionary EventListenerOptions {
-  boolean capture = false;
-};
-
-dictionary AddEventListenerOptions : EventListenerOptions {
-  boolean passive = false;
-  boolean once = false;
-};
-
-[Constructor,
- Exposed=(Window,Worker)]
-interface AbortController {
-  [SameObject] readonly attribute AbortSignal signal;
-
-  void abort();
-};
-
-[Exposed=(Window,Worker)]
-interface AbortSignal : EventTarget {
-  readonly attribute boolean aborted;
-
-  attribute EventHandler onabort;
-};
-
-interface mixin NonElementParentNode {
-  Element? getElementById(DOMString elementId);
-};
-Document includes NonElementParentNode;
-DocumentFragment includes NonElementParentNode;
-
-interface mixin DocumentOrShadowRoot {
-};
-Document includes DocumentOrShadowRoot;
-ShadowRoot includes DocumentOrShadowRoot;
-
-interface mixin ParentNode {
-  [SameObject] readonly attribute HTMLCollection children;
-  readonly attribute Element? firstElementChild;
-  readonly attribute Element? lastElementChild;
-  readonly attribute unsigned long childElementCount;
-
-  [CEReactions, Unscopable] void prepend((Node or DOMString)... nodes);
-  [CEReactions, Unscopable] void append((Node or DOMString)... nodes);
-
-  Element? querySelector(DOMString selectors);
-  [NewObject] NodeList querySelectorAll(DOMString selectors);
-};
-Document includes ParentNode;
-DocumentFragment includes ParentNode;
-Element includes ParentNode;
-
-interface mixin NonDocumentTypeChildNode {
-  readonly attribute Element? previousElementSibling;
-  readonly attribute Element? nextElementSibling;
-};
-Element includes NonDocumentTypeChildNode;
-CharacterData includes NonDocumentTypeChildNode;
-
-interface mixin ChildNode {
-  [CEReactions, Unscopable] void before((Node or DOMString)... nodes);
-  [CEReactions, Unscopable] void after((Node or DOMString)... nodes);
-  [CEReactions, Unscopable] void replaceWith((Node or DOMString)... nodes);
-  [CEReactions, Unscopable] void remove();
-};
-DocumentType includes ChildNode;
-Element includes ChildNode;
-CharacterData includes ChildNode;
-
-interface mixin Slotable {
-  readonly attribute HTMLSlotElement? assignedSlot;
-};
-Element includes Slotable;
-Text includes Slotable;
-
-[Exposed=Window]
-interface NodeList {
-  getter Node? item(unsigned long index);
-  readonly attribute unsigned long length;
-  iterable<Node>;
-};
-
-[Exposed=Window, LegacyUnenumerableNamedProperties]
-interface HTMLCollection {
-  readonly attribute unsigned long length;
-  getter Element? item(unsigned long index);
-  getter Element? namedItem(DOMString name);
-};
-
-[Constructor(MutationCallback callback),
- Exposed=Window]
-interface MutationObserver {
-  void observe(Node target, optional MutationObserverInit options);
-  void disconnect();
-  sequence<MutationRecord> takeRecords();
-};
-
-callback MutationCallback = void (sequence<MutationRecord> mutations, MutationObserver observer);
-
-dictionary MutationObserverInit {
-  boolean childList = false;
-  boolean attributes;
-  boolean characterData;
-  boolean subtree = false;
-  boolean attributeOldValue;
-  boolean characterDataOldValue;
-  sequence<DOMString> attributeFilter;
-};
-
-[Exposed=Window]
-interface MutationRecord {
-  readonly attribute DOMString type;
-  [SameObject] readonly attribute Node target;
-  [SameObject] readonly attribute NodeList addedNodes;
-  [SameObject] readonly attribute NodeList removedNodes;
-  readonly attribute Node? previousSibling;
-  readonly attribute Node? nextSibling;
-  readonly attribute DOMString? attributeName;
-  readonly attribute DOMString? attributeNamespace;
-  readonly attribute DOMString? oldValue;
-};
-
-[Exposed=Window]
-interface Node : EventTarget {
-  const unsigned short ELEMENT_NODE = 1;
-  const unsigned short ATTRIBUTE_NODE = 2;
-  const unsigned short TEXT_NODE = 3;
-  const unsigned short CDATA_SECTION_NODE = 4;
-  const unsigned short ENTITY_REFERENCE_NODE = 5; // historical
-  const unsigned short ENTITY_NODE = 6; // historical
-  const unsigned short PROCESSING_INSTRUCTION_NODE = 7;
-  const unsigned short COMMENT_NODE = 8;
-  const unsigned short DOCUMENT_NODE = 9;
-  const unsigned short DOCUMENT_TYPE_NODE = 10;
-  const unsigned short DOCUMENT_FRAGMENT_NODE = 11;
-  const unsigned short NOTATION_NODE = 12; // historical
-  readonly attribute unsigned short nodeType;
-  readonly attribute DOMString nodeName;
-
-  readonly attribute USVString baseURI;
-
-  readonly attribute boolean isConnected;
-  readonly attribute Document? ownerDocument;
-  Node getRootNode(optional GetRootNodeOptions options);
-  readonly attribute Node? parentNode;
-  readonly attribute Element? parentElement;
-  boolean hasChildNodes();
-  [SameObject] readonly attribute NodeList childNodes;
-  readonly attribute Node? firstChild;
-  readonly attribute Node? lastChild;
-  readonly attribute Node? previousSibling;
-  readonly attribute Node? nextSibling;
-
-  [CEReactions] attribute DOMString? nodeValue;
-  [CEReactions] attribute DOMString? textContent;
-  [CEReactions] void normalize();
-
-  [CEReactions, NewObject] Node cloneNode(optional boolean deep = false);
-  boolean isEqualNode(Node? otherNode);
-  boolean isSameNode(Node? otherNode); // historical alias of ===
-
-  const unsigned short DOCUMENT_POSITION_DISCONNECTED = 0x01;
-  const unsigned short DOCUMENT_POSITION_PRECEDING = 0x02;
-  const unsigned short DOCUMENT_POSITION_FOLLOWING = 0x04;
-  const unsigned short DOCUMENT_POSITION_CONTAINS = 0x08;
-  const unsigned short DOCUMENT_POSITION_CONTAINED_BY = 0x10;
-  const unsigned short DOCUMENT_POSITION_IMPLEMENTATION_SPECIFIC = 0x20;
-  unsigned short compareDocumentPosition(Node other);
-  boolean contains(Node? other);
-
-  DOMString? lookupPrefix(DOMString? namespace);
-  DOMString? lookupNamespaceURI(DOMString? prefix);
-  boolean isDefaultNamespace(DOMString? namespace);
-
-  [CEReactions] Node insertBefore(Node node, Node? child);
-  [CEReactions] Node appendChild(Node node);
-  [CEReactions] Node replaceChild(Node node, Node child);
-  [CEReactions] Node removeChild(Node child);
-};
-
-dictionary GetRootNodeOptions {
-  boolean composed = false;
-};
-
-[Constructor,
- Exposed=Window]
-interface Document : Node {
-  [SameObject] readonly attribute DOMImplementation implementation;
-  readonly attribute USVString URL;
-  readonly attribute USVString documentURI;
-  readonly attribute USVString origin;
-  readonly attribute DOMString compatMode;
-  readonly attribute DOMString characterSet;
-  readonly attribute DOMString charset; // historical alias of .characterSet
-  readonly attribute DOMString inputEncoding; // historical alias of .characterSet
-  readonly attribute DOMString contentType;
-
-  readonly attribute DocumentType? doctype;
-  readonly attribute Element? documentElement;
-  HTMLCollection getElementsByTagName(DOMString qualifiedName);
-  HTMLCollection getElementsByTagNameNS(DOMString? namespace, DOMString localName);
-  HTMLCollection getElementsByClassName(DOMString classNames);
-
-  [CEReactions, NewObject] Element createElement(DOMString localName, optional (DOMString or ElementCreationOptions) options);
-  [CEReactions, NewObject] Element createElementNS(DOMString? namespace, DOMString qualifiedName, optional (DOMString or ElementCreationOptions) options);
-  [NewObject] DocumentFragment createDocumentFragment();
-  [NewObject] Text createTextNode(DOMString data);
-  [NewObject] CDATASection createCDATASection(DOMString data);
-  [NewObject] Comment createComment(DOMString data);
-  [NewObject] ProcessingInstruction createProcessingInstruction(DOMString target, DOMString data);
-
-  [CEReactions, NewObject] Node importNode(Node node, optional boolean deep = false);
-  [CEReactions] Node adoptNode(Node node);
-
-  [NewObject] Attr createAttribute(DOMString localName);
-  [NewObject] Attr createAttributeNS(DOMString? namespace, DOMString qualifiedName);
-
-  [NewObject] Event createEvent(DOMString interface);
-
-  [NewObject] Range createRange();
-
-  // NodeFilter.SHOW_ALL = 0xFFFFFFFF
-  [NewObject] NodeIterator createNodeIterator(Node root, optional unsigned long whatToShow = 0xFFFFFFFF, optional NodeFilter? filter = null);
-  [NewObject] TreeWalker createTreeWalker(Node root, optional unsigned long whatToShow = 0xFFFFFFFF, optional NodeFilter? filter = null);
-};
-
-[Exposed=Window]
-interface XMLDocument : Document {};
-
-dictionary ElementCreationOptions {
-  DOMString is;
-};
-
-[Exposed=Window]
-interface DOMImplementation {
-  [NewObject] DocumentType createDocumentType(DOMString qualifiedName, DOMString publicId, DOMString systemId);
-  [NewObject] XMLDocument createDocument(DOMString? namespace, [TreatNullAs=EmptyString] DOMString qualifiedName, optional DocumentType? doctype = null);
-  [NewObject] Document createHTMLDocument(optional DOMString title);
-
-  boolean hasFeature(); // useless; always returns true
-};
-
-[Exposed=Window]
-interface DocumentType : Node {
-  readonly attribute DOMString name;
-  readonly attribute DOMString publicId;
-  readonly attribute DOMString systemId;
-};
-
-[Constructor,
- Exposed=Window]
-interface DocumentFragment : Node {
-};
-
-[Exposed=Window]
-interface ShadowRoot : DocumentFragment {
-  readonly attribute ShadowRootMode mode;
-  readonly attribute Element host;
-};
-
-enum ShadowRootMode { "open", "closed" };
-
-[Exposed=Window]
-interface Element : Node {
-  readonly attribute DOMString? namespaceURI;
-  readonly attribute DOMString? prefix;
-  readonly attribute DOMString localName;
-  readonly attribute DOMString tagName;
-
-  [CEReactions] attribute DOMString id;
-  [CEReactions] attribute DOMString className;
-  [SameObject, PutForwards=value] readonly attribute DOMTokenList classList;
-  [CEReactions, Unscopable] attribute DOMString slot;
-
-  boolean hasAttributes();
-  [SameObject] readonly attribute NamedNodeMap attributes;
-  sequence<DOMString> getAttributeNames();
-  DOMString? getAttribute(DOMString qualifiedName);
-  DOMString? getAttributeNS(DOMString? namespace, DOMString localName);
-  [CEReactions] void setAttribute(DOMString qualifiedName, DOMString value);
-  [CEReactions] void setAttributeNS(DOMString? namespace, DOMString qualifiedName, DOMString value);
-  [CEReactions] void removeAttribute(DOMString qualifiedName);
-  [CEReactions] void removeAttributeNS(DOMString? namespace, DOMString localName);
-  boolean hasAttribute(DOMString qualifiedName);
-  boolean hasAttributeNS(DOMString? namespace, DOMString localName);
-
-  Attr? getAttributeNode(DOMString qualifiedName);
-  Attr? getAttributeNodeNS(DOMString? namespace, DOMString localName);
-  [CEReactions] Attr? setAttributeNode(Attr attr);
-  [CEReactions] Attr? setAttributeNodeNS(Attr attr);
-  [CEReactions] Attr removeAttributeNode(Attr attr);
-
-  ShadowRoot attachShadow(ShadowRootInit init);
-  readonly attribute ShadowRoot? shadowRoot;
-
-  Element? closest(DOMString selectors);
-  boolean matches(DOMString selectors);
-  boolean webkitMatchesSelector(DOMString selectors); // historical alias of .matches
-
-  HTMLCollection getElementsByTagName(DOMString qualifiedName);
-  HTMLCollection getElementsByTagNameNS(DOMString? namespace, DOMString localName);
-  HTMLCollection getElementsByClassName(DOMString classNames);
-
-  [CEReactions] Element? insertAdjacentElement(DOMString where, Element element); // historical
-  void insertAdjacentText(DOMString where, DOMString data); // historical
-};
-
-dictionary ShadowRootInit {
-  required ShadowRootMode mode;
-};
-
-[Exposed=Window,
- LegacyUnenumerableNamedProperties]
-interface NamedNodeMap {
-  readonly attribute unsigned long length;
-  getter Attr? item(unsigned long index);
-  getter Attr? getNamedItem(DOMString qualifiedName);
-  Attr? getNamedItemNS(DOMString? namespace, DOMString localName);
-  [CEReactions] Attr? setNamedItem(Attr attr);
-  [CEReactions] Attr? setNamedItemNS(Attr attr);
-  [CEReactions] Attr removeNamedItem(DOMString qualifiedName);
-  [CEReactions] Attr removeNamedItemNS(DOMString? namespace, DOMString localName);
-};
-
-[Exposed=Window]
-interface Attr : Node {
-  readonly attribute DOMString? namespaceURI;
-  readonly attribute DOMString? prefix;
-  readonly attribute DOMString localName;
-  readonly attribute DOMString name;
-  [CEReactions] attribute DOMString value;
-
-  readonly attribute Element? ownerElement;
-
-  readonly attribute boolean specified; // useless; always returns true
-};
-
-[Exposed=Window]
-interface CharacterData : Node {
-  attribute [TreatNullAs=EmptyString] DOMString data;
-  readonly attribute unsigned long length;
-  DOMString substringData(unsigned long offset, unsigned long count);
-  void appendData(DOMString data);
-  void insertData(unsigned long offset, DOMString data);
-  void deleteData(unsigned long offset, unsigned long count);
-  void replaceData(unsigned long offset, unsigned long count, DOMString data);
-};
-
-[Constructor(optional DOMString data = ""),
- Exposed=Window]
-interface Text : CharacterData {
-  [NewObject] Text splitText(unsigned long offset);
-  readonly attribute DOMString wholeText;
-};
-
-[Exposed=Window]
-interface CDATASection : Text {
-};
-
-[Exposed=Window]
-interface ProcessingInstruction : CharacterData {
-  readonly attribute DOMString target;
-};
-
-[Constructor(optional DOMString data = ""),
- Exposed=Window]
-interface Comment : CharacterData {
-};
-
-[Exposed=Window]
-interface AbstractRange {
-  readonly attribute Node startContainer;
-  readonly attribute unsigned long startOffset;
-  readonly attribute Node endContainer;
-  readonly attribute unsigned long endOffset;
-  readonly attribute boolean collapsed;
-};
-
-[Exposed=Window]
-interface StaticRange : AbstractRange {
-};
-
-[Constructor,
- Exposed=Window]
-interface Range : AbstractRange {
-  readonly attribute Node commonAncestorContainer;
-
-  void setStart(Node node, unsigned long offset);
-  void setEnd(Node node, unsigned long offset);
-  void setStartBefore(Node node);
-  void setStartAfter(Node node);
-  void setEndBefore(Node node);
-  void setEndAfter(Node node);
-  void collapse(optional boolean toStart = false);
-  void selectNode(Node node);
-  void selectNodeContents(Node node);
-
-  const unsigned short START_TO_START = 0;
-  const unsigned short START_TO_END = 1;
-  const unsigned short END_TO_END = 2;
-  const unsigned short END_TO_START = 3;
-  short compareBoundaryPoints(unsigned short how, Range sourceRange);
-
-  [CEReactions] void deleteContents();
-  [CEReactions, NewObject] DocumentFragment extractContents();
-  [CEReactions, NewObject] DocumentFragment cloneContents();
-  [CEReactions] void insertNode(Node node);
-  [CEReactions] void surroundContents(Node newParent);
-
-  [NewObject] Range cloneRange();
-  void detach();
-
-  boolean isPointInRange(Node node, unsigned long offset);
-  short comparePoint(Node node, unsigned long offset);
-
-  boolean intersectsNode(Node node);
-
-  stringifier;
-};
-
-[Exposed=Window]
-interface NodeIterator {
-  [SameObject] readonly attribute Node root;
-  readonly attribute Node referenceNode;
-  readonly attribute boolean pointerBeforeReferenceNode;
-  readonly attribute unsigned long whatToShow;
-  readonly attribute NodeFilter? filter;
-
-  Node? nextNode();
-  Node? previousNode();
-
-  void detach();
-};
-
-[Exposed=Window]
-interface TreeWalker {
-  [SameObject] readonly attribute Node root;
-  readonly attribute unsigned long whatToShow;
-  readonly attribute NodeFilter? filter;
-           attribute Node currentNode;
-
-  Node? parentNode();
-  Node? firstChild();
-  Node? lastChild();
-  Node? previousSibling();
-  Node? nextSibling();
-  Node? previousNode();
-  Node? nextNode();
-};
-
-[Exposed=Window]
-callback interface NodeFilter {
-  // Constants for acceptNode()
-  const unsigned short FILTER_ACCEPT = 1;
-  const unsigned short FILTER_REJECT = 2;
-  const unsigned short FILTER_SKIP = 3;
-
-  // Constants for whatToShow
-  const unsigned long SHOW_ALL = 0xFFFFFFFF;
-  const unsigned long SHOW_ELEMENT = 0x1;
-  const unsigned long SHOW_ATTRIBUTE = 0x2;
-  const unsigned long SHOW_TEXT = 0x4;
-  const unsigned long SHOW_CDATA_SECTION = 0x8;
-  const unsigned long SHOW_ENTITY_REFERENCE = 0x10; // historical
-  const unsigned long SHOW_ENTITY = 0x20; // historical
-  const unsigned long SHOW_PROCESSING_INSTRUCTION = 0x40;
-  const unsigned long SHOW_COMMENT = 0x80;
-  const unsigned long SHOW_DOCUMENT = 0x100;
-  const unsigned long SHOW_DOCUMENT_TYPE = 0x200;
-  const unsigned long SHOW_DOCUMENT_FRAGMENT = 0x400;
-  const unsigned long SHOW_NOTATION = 0x800; // historical
-
-  unsigned short acceptNode(Node node);
-};
-
-[Exposed=Window]
-interface DOMTokenList {
-  readonly attribute unsigned long length;
-  getter DOMString? item(unsigned long index);
-  boolean contains(DOMString token);
-  [CEReactions] void add(DOMString... tokens);
-  [CEReactions] void remove(DOMString... tokens);
-  [CEReactions] boolean toggle(DOMString token, optional boolean force);
-  [CEReactions] boolean replace(DOMString token, DOMString newToken);
-  boolean supports(DOMString token);
-  [CEReactions] stringifier attribute DOMString value;
-  iterable<DOMString>;
-};
diff --git a/third_party/rust/weedle/tests/defs/html.webidl b/third_party/rust/weedle/tests/defs/html.webidl
deleted file mode 100644
index 83e009aac5..0000000000
--- a/third_party/rust/weedle/tests/defs/html.webidl
+++ /dev/null
@@ -1,2408 +0,0 @@
-[Exposed=Window,
- LegacyUnenumerableNamedProperties]
-interface HTMLAllCollection {
-  readonly attribute unsigned long length;
-  getter Element (unsigned long index);
-  getter (HTMLCollection or Element)? namedItem(DOMString name);
-  (HTMLCollection or Element)? item(optional DOMString nameOrIndex);
-
-  // Note: HTMLAllCollection objects have a custom [[Call]] internal method and an [[IsHTMLDDA]] internal slot.
-};
-
-[Exposed=Window]
-interface HTMLFormControlsCollection : HTMLCollection {
-  // inherits length and item()
-  getter (RadioNodeList or Element)? namedItem(DOMString name); // shadows inherited namedItem()
-};
-
-[Exposed=Window]
-interface RadioNodeList : NodeList {
-  attribute DOMString value;
-};
-
-[Exposed=Window]
-interface HTMLOptionsCollection : HTMLCollection {
-  // inherits item(), namedItem()
-  [CEReactions] attribute unsigned long length; // shadows inherited length
-  [CEReactions] setter void (unsigned long index, HTMLOptionElement? option);
-  [CEReactions] void add((HTMLOptionElement or HTMLOptGroupElement) element, optional (HTMLElement or long)? before = null);
-  [CEReactions] void remove(long index);
-  attribute long selectedIndex;
-};
-
-[Exposed=(Window,Worker)]
-interface DOMStringList {
-  readonly attribute unsigned long length;
-  getter DOMString? item(unsigned long index);
-  boolean contains(DOMString string);
-};
-
-enum DocumentReadyState { "loading", "interactive", "complete" };
-typedef (HTMLScriptElement or SVGScriptElement) HTMLOrSVGScriptElement;
-
-[OverrideBuiltins]
-partial interface Document {
-  // resource metadata management
-  [PutForwards=href, Unforgeable] readonly attribute Location? location;
-  attribute USVString domain;
-  readonly attribute USVString referrer;
-  attribute USVString cookie;
-  readonly attribute DOMString lastModified;
-  readonly attribute DocumentReadyState readyState;
-
-  // DOM tree accessors
-  getter object (DOMString name);
-  [CEReactions] attribute DOMString title;
-  [CEReactions] attribute DOMString dir;
-  [CEReactions] attribute HTMLElement? body;
-  readonly attribute HTMLHeadElement? head;
-  [SameObject] readonly attribute HTMLCollection images;
-  [SameObject] readonly attribute HTMLCollection embeds;
-  [SameObject] readonly attribute HTMLCollection plugins;
-  [SameObject] readonly attribute HTMLCollection links;
-  [SameObject] readonly attribute HTMLCollection forms;
-  [SameObject] readonly attribute HTMLCollection scripts;
-  NodeList getElementsByName(DOMString elementName);
-  readonly attribute HTMLOrSVGScriptElement? currentScript; // classic scripts in a document tree only
-
-  // dynamic markup insertion
-  [CEReactions] Document open(optional DOMString type, optional DOMString replace = ""); // type is ignored
-  WindowProxy open(USVString url, DOMString name, DOMString features);
-  [CEReactions] void close();
-  [CEReactions] void write(DOMString... text);
-  [CEReactions] void writeln(DOMString... text);
-
-  // user interaction
-  readonly attribute WindowProxy? defaultView;
-  readonly attribute Element? activeElement;
-  boolean hasFocus();
-  [CEReactions] attribute DOMString designMode;
-  [CEReactions] boolean execCommand(DOMString commandId, optional boolean showUI = false, optional DOMString value = "");
-  boolean queryCommandEnabled(DOMString commandId);
-  boolean queryCommandIndeterm(DOMString commandId);
-  boolean queryCommandState(DOMString commandId);
-  boolean queryCommandSupported(DOMString commandId);
-  DOMString queryCommandValue(DOMString commandId);
-
-  // special event handler IDL attributes that only apply to Document objects
-  [LenientThis] attribute EventHandler onreadystatechange;
-};
-Document includes GlobalEventHandlers;
-Document includes DocumentAndElementEventHandlers;
-
-[Exposed=Window,
- HTMLConstructor]
-interface HTMLElement : Element {
-  // metadata attributes
-  [CEReactions] attribute DOMString title;
-  [CEReactions] attribute DOMString lang;
-  [CEReactions] attribute boolean translate;
-  [CEReactions] attribute DOMString dir;
-
-  // user interaction
-  [CEReactions] attribute boolean hidden;
-  void click();
-  [CEReactions] attribute DOMString accessKey;
-  readonly attribute DOMString accessKeyLabel;
-  [CEReactions] attribute boolean draggable;
-  [CEReactions] attribute boolean spellcheck;
-  [CEReactions] attribute DOMString autocapitalize;
-
-  [CEReactions] attribute [TreatNullAs=EmptyString] DOMString innerText;
-};
-
-HTMLElement includes GlobalEventHandlers;
-HTMLElement includes DocumentAndElementEventHandlers;
-HTMLElement includes ElementContentEditable;
-
-// Note: intentionally not [HTMLConstructor]
-[Exposed=Window]
-interface HTMLUnknownElement : HTMLElement { };
-
-interface mixin HTMLOrSVGElement {
-  [SameObject] readonly attribute DOMStringMap dataset;
-  attribute DOMString nonce;
-
-  [CEReactions] attribute long tabIndex;
-  void focus(optional FocusOptions options = {});
-  void blur();
-};
-HTMLElement includes HTMLOrSVGElement;
-SVGElement includes HTMLOrSVGElement;
-
-[Exposed=Window,
- OverrideBuiltins]
-interface DOMStringMap {
-  getter DOMString (DOMString name);
-  [CEReactions] setter void (DOMString name, DOMString value);
-  [CEReactions] deleter void (DOMString name);
-};
-
-[Exposed=Window,
- HTMLConstructor]
-interface HTMLHtmlElement : HTMLElement {};
-
-[Exposed=Window,
- HTMLConstructor]
-interface HTMLHeadElement : HTMLElement {};
-
-[Exposed=Window,
- HTMLConstructor]
-interface HTMLTitleElement : HTMLElement {
-  [CEReactions] attribute DOMString text;
-};
-
-[Exposed=Window,
- HTMLConstructor]
-interface HTMLBaseElement : HTMLElement {
-  [CEReactions] attribute USVString href;
-  [CEReactions] attribute DOMString target;
-};
-
-[Exposed=Window,
- HTMLConstructor]
-interface HTMLLinkElement : HTMLElement {
-  [CEReactions] attribute USVString href;
-  [CEReactions] attribute DOMString? crossOrigin;
-  [CEReactions] attribute DOMString rel;
-  [CEReactions] attribute DOMString as; // (default "")
-  [SameObject, PutForwards=value] readonly attribute DOMTokenList relList;
-  [CEReactions] attribute DOMString media;
-  [CEReactions] attribute DOMString integrity;
-  [CEReactions] attribute DOMString hreflang;
-  [CEReactions] attribute DOMString type;
-  [SameObject, PutForwards=value] readonly attribute DOMTokenList sizes;
-  [CEReactions] attribute DOMString referrerPolicy;
-};
-HTMLLinkElement includes LinkStyle;
-
-[Exposed=Window,
- HTMLConstructor]
-interface HTMLMetaElement : HTMLElement {
-  [CEReactions] attribute DOMString name;
-  [CEReactions] attribute DOMString httpEquiv;
-  [CEReactions] attribute DOMString content;
-};
-
-[Exposed=Window,
- HTMLConstructor]
-interface HTMLStyleElement : HTMLElement {
-  [CEReactions] attribute DOMString media;
-};
-HTMLStyleElement includes LinkStyle;
-
-[Exposed=Window,
- HTMLConstructor]
-interface HTMLBodyElement : HTMLElement {};
-
-HTMLBodyElement includes WindowEventHandlers;
-
-[Exposed=Window,
- HTMLConstructor]
-interface HTMLHeadingElement : HTMLElement {};
-
-[Exposed=Window,
- HTMLConstructor]
-interface HTMLParagraphElement : HTMLElement {};
-
-[Exposed=Window,
- HTMLConstructor]
-interface HTMLHRElement : HTMLElement {};
-
-[Exposed=Window,
- HTMLConstructor]
-interface HTMLPreElement : HTMLElement {};
-
-[Exposed=Window,
- HTMLConstructor]
-interface HTMLQuoteElement : HTMLElement {
-  [CEReactions] attribute USVString cite;
-};
-
-[Exposed=Window,
- HTMLConstructor]
-interface HTMLOListElement : HTMLElement {
-  [CEReactions] attribute boolean reversed;
-  [CEReactions] attribute long start;
-  [CEReactions] attribute DOMString type;
-};
-
-[Exposed=Window,
- HTMLConstructor]
-interface HTMLUListElement : HTMLElement {};
-
-[Exposed=Window,
- HTMLConstructor]
-interface HTMLMenuElement : HTMLElement {
-};
-
-[Exposed=Window,
- HTMLConstructor]
-interface HTMLLIElement : HTMLElement {
-  [CEReactions] attribute long value;
-};
-
-[Exposed=Window,
- HTMLConstructor]
-interface HTMLDListElement : HTMLElement {};
-
-[Exposed=Window,
- HTMLConstructor]
-interface HTMLDivElement : HTMLElement {};
-
-[Exposed=Window,
- HTMLConstructor]
-interface HTMLAnchorElement : HTMLElement {
-  [CEReactions] attribute DOMString target;
-  [CEReactions] attribute DOMString download;
-  [CEReactions] attribute USVString ping;
-  [CEReactions] attribute DOMString rel;
-  [SameObject, PutForwards=value] readonly attribute DOMTokenList relList;
-  [CEReactions] attribute DOMString hreflang;
-  [CEReactions] attribute DOMString type;
-
-  [CEReactions] attribute DOMString text;
-
-  [CEReactions] attribute DOMString referrerPolicy;
-};
-HTMLAnchorElement includes HTMLHyperlinkElementUtils;
-
-[Exposed=Window,
- HTMLConstructor]
-interface HTMLDataElement : HTMLElement {
-  [CEReactions] attribute DOMString value;
-};
-
-[Exposed=Window,
- HTMLConstructor]
-interface HTMLTimeElement : HTMLElement {
-  [CEReactions] attribute DOMString dateTime;
-};
-
-[Exposed=Window,
- HTMLConstructor]
-interface HTMLSpanElement : HTMLElement {};
-
-[Exposed=Window,
- HTMLConstructor]
-interface HTMLBRElement : HTMLElement {};
-
-interface mixin HTMLHyperlinkElementUtils {
-  [CEReactions] stringifier attribute USVString href;
-  readonly attribute USVString origin;
-  [CEReactions] attribute USVString protocol;
-  [CEReactions] attribute USVString username;
-  [CEReactions] attribute USVString password;
-  [CEReactions] attribute USVString host;
-  [CEReactions] attribute USVString hostname;
-  [CEReactions] attribute USVString port;
-  [CEReactions] attribute USVString pathname;
-  [CEReactions] attribute USVString search;
-  [CEReactions] attribute USVString hash;
-};
-
-[Exposed=Window,
- HTMLConstructor]
-interface HTMLModElement : HTMLElement {
-  [CEReactions] attribute USVString cite;
-  [CEReactions] attribute DOMString dateTime;
-};
-
-[Exposed=Window,
- HTMLConstructor]
-interface HTMLPictureElement : HTMLElement {};
-
-[Exposed=Window,
- HTMLConstructor]
-interface HTMLSourceElement : HTMLElement {
-  [CEReactions] attribute USVString src;
-  [CEReactions] attribute DOMString type;
-  [CEReactions] attribute USVString srcset;
-  [CEReactions] attribute DOMString sizes;
-  [CEReactions] attribute DOMString media;
-};
-
-[Exposed=Window,
- HTMLConstructor,
- NamedConstructor=Image(optional unsigned long width, optional unsigned long height)]
-interface HTMLImageElement : HTMLElement {
-  [CEReactions] attribute DOMString alt;
-  [CEReactions] attribute USVString src;
-  [CEReactions] attribute USVString srcset;
-  [CEReactions] attribute DOMString sizes;
-  [CEReactions] attribute DOMString? crossOrigin;
-  [CEReactions] attribute DOMString useMap;
-  [CEReactions] attribute boolean isMap;
-  [CEReactions] attribute unsigned long width;
-  [CEReactions] attribute unsigned long height;
-  readonly attribute unsigned long naturalWidth;
-  readonly attribute unsigned long naturalHeight;
-  readonly attribute boolean complete;
-  readonly attribute USVString currentSrc;
-  [CEReactions] attribute DOMString referrerPolicy;
-  [CEReactions] attribute DOMString decoding;
-
-  Promise<void> decode();
-};
-
-[Exposed=Window,
- HTMLConstructor]
-interface HTMLIFrameElement : HTMLElement {
-  [CEReactions] attribute USVString src;
-  [CEReactions] attribute DOMString srcdoc;
-  [CEReactions] attribute DOMString name;
-  [SameObject, PutForwards=value] readonly attribute DOMTokenList sandbox;
-  [CEReactions] attribute boolean allowFullscreen;
-  [CEReactions] attribute boolean allowPaymentRequest;
-  [CEReactions] attribute boolean allowUserMedia;
-  [CEReactions] attribute DOMString width;
-  [CEReactions] attribute DOMString height;
-  [CEReactions] attribute DOMString referrerPolicy;
-  readonly attribute Document? contentDocument;
-  readonly attribute WindowProxy? contentWindow;
-  Document? getSVGDocument();
-};
-
-[Exposed=Window,
- HTMLConstructor]
-interface HTMLEmbedElement : HTMLElement {
-  [CEReactions] attribute USVString src;
-  [CEReactions] attribute DOMString type;
-  [CEReactions] attribute DOMString width;
-  [CEReactions] attribute DOMString height;
-  Document? getSVGDocument();
-};
-
-[Exposed=Window,
- HTMLConstructor]
-interface HTMLObjectElement : HTMLElement {
-  [CEReactions] attribute USVString data;
-  [CEReactions] attribute DOMString type;
-  [CEReactions] attribute boolean typeMustMatch;
-  [CEReactions] attribute DOMString name;
-  [CEReactions] attribute DOMString useMap;
-  readonly attribute HTMLFormElement? form;
-  [CEReactions] attribute DOMString width;
-  [CEReactions] attribute DOMString height;
-  readonly attribute Document? contentDocument;
-  readonly attribute WindowProxy? contentWindow;
-  Document? getSVGDocument();
-
-  readonly attribute boolean willValidate;
-  readonly attribute ValidityState validity;
-  readonly attribute DOMString validationMessage;
-  boolean checkValidity();
-  boolean reportValidity();
-  void setCustomValidity(DOMString error);
-};
-
-[Exposed=Window,
- HTMLConstructor]
-interface HTMLParamElement : HTMLElement {
-  [CEReactions] attribute DOMString name;
-  [CEReactions] attribute DOMString value;
-};
-
-[Exposed=Window,
- HTMLConstructor]
-interface HTMLVideoElement : HTMLMediaElement {
-  [CEReactions] attribute unsigned long width;
-  [CEReactions] attribute unsigned long height;
-  readonly attribute unsigned long videoWidth;
-  readonly attribute unsigned long videoHeight;
-  [CEReactions] attribute USVString poster;
-  [CEReactions] attribute boolean playsInline;
-};
-
-[Exposed=Window,
- HTMLConstructor,
- NamedConstructor=Audio(optional DOMString src)]
-interface HTMLAudioElement : HTMLMediaElement {};
-
-[Exposed=Window,
- HTMLConstructor]
-interface HTMLTrackElement : HTMLElement {
-  [CEReactions] attribute DOMString kind;
-  [CEReactions] attribute USVString src;
-  [CEReactions] attribute DOMString srclang;
-  [CEReactions] attribute DOMString label;
-  [CEReactions] attribute boolean default;
-
-  const unsigned short NONE = 0;
-  const unsigned short LOADING = 1;
-  const unsigned short LOADED = 2;
-  const unsigned short ERROR = 3;
-  readonly attribute unsigned short readyState;
-
-  readonly attribute TextTrack track;
-};
-
-enum CanPlayTypeResult { "" /* empty string */, "maybe", "probably" };
-typedef (MediaStream or MediaSource or Blob) MediaProvider;
-
-[Exposed=Window]
-interface HTMLMediaElement : HTMLElement {
-
-  // error state
-  readonly attribute MediaError? error;
-
-  // network state
-  [CEReactions] attribute USVString src;
-  attribute MediaProvider? srcObject;
-  readonly attribute USVString currentSrc;
-  [CEReactions] attribute DOMString? crossOrigin;
-  const unsigned short NETWORK_EMPTY = 0;
-  const unsigned short NETWORK_IDLE = 1;
-  const unsigned short NETWORK_LOADING = 2;
-  const unsigned short NETWORK_NO_SOURCE = 3;
-  readonly attribute unsigned short networkState;
-  [CEReactions] attribute DOMString preload;
-  readonly attribute TimeRanges buffered;
-  void load();
-  CanPlayTypeResult canPlayType(DOMString type);
-
-  // ready state
-  const unsigned short HAVE_NOTHING = 0;
-  const unsigned short HAVE_METADATA = 1;
-  const unsigned short HAVE_CURRENT_DATA = 2;
-  const unsigned short HAVE_FUTURE_DATA = 3;
-  const unsigned short HAVE_ENOUGH_DATA = 4;
-  readonly attribute unsigned short readyState;
-  readonly attribute boolean seeking;
-
-  // playback state
-  attribute double currentTime;
-  void fastSeek(double time);
-  readonly attribute unrestricted double duration;
-  object getStartDate();
-  readonly attribute boolean paused;
-  attribute double defaultPlaybackRate;
-  attribute double playbackRate;
-  readonly attribute TimeRanges played;
-  readonly attribute TimeRanges seekable;
-  readonly attribute boolean ended;
-  [CEReactions] attribute boolean autoplay;
-  [CEReactions] attribute boolean loop;
-  Promise<void> play();
-  void pause();
-
-  // controls
-  [CEReactions] attribute boolean controls;
-  attribute double volume;
-  attribute boolean muted;
-  [CEReactions] attribute boolean defaultMuted;
-
-  // tracks
-  [SameObject] readonly attribute AudioTrackList audioTracks;
-  [SameObject] readonly attribute VideoTrackList videoTracks;
-  [SameObject] readonly attribute TextTrackList textTracks;
-  TextTrack addTextTrack(TextTrackKind kind, optional DOMString label = "", optional DOMString language = "");
-};
-
-[Exposed=Window]
-interface MediaError {
-  const unsigned short MEDIA_ERR_ABORTED = 1;
-  const unsigned short MEDIA_ERR_NETWORK = 2;
-  const unsigned short MEDIA_ERR_DECODE = 3;
-  const unsigned short MEDIA_ERR_SRC_NOT_SUPPORTED = 4;
-
-  readonly attribute unsigned short code;
-  readonly attribute DOMString message;
-};
-
-[Exposed=Window]
-interface AudioTrackList : EventTarget {
-  readonly attribute unsigned long length;
-  getter AudioTrack (unsigned long index);
-  AudioTrack? getTrackById(DOMString id);
-
-  attribute EventHandler onchange;
-  attribute EventHandler onaddtrack;
-  attribute EventHandler onremovetrack;
-};
-
-[Exposed=Window]
-interface AudioTrack {
-  readonly attribute DOMString id;
-  readonly attribute DOMString kind;
-  readonly attribute DOMString label;
-  readonly attribute DOMString language;
-  attribute boolean enabled;
-};
-
-[Exposed=Window]
-interface VideoTrackList : EventTarget {
-  readonly attribute unsigned long length;
-  getter VideoTrack (unsigned long index);
-  VideoTrack? getTrackById(DOMString id);
-  readonly attribute long selectedIndex;
-
-  attribute EventHandler onchange;
-  attribute EventHandler onaddtrack;
-  attribute EventHandler onremovetrack;
-};
-
-[Exposed=Window]
-interface VideoTrack {
-  readonly attribute DOMString id;
-  readonly attribute DOMString kind;
-  readonly attribute DOMString label;
-  readonly attribute DOMString language;
-  attribute boolean selected;
-};
-
-[Exposed=Window]
-interface TextTrackList : EventTarget {
-  readonly attribute unsigned long length;
-  getter TextTrack (unsigned long index);
-  TextTrack? getTrackById(DOMString id);
-
-  attribute EventHandler onchange;
-  attribute EventHandler onaddtrack;
-  attribute EventHandler onremovetrack;
-};
-
-enum TextTrackMode { "disabled",  "hidden",  "showing" };
-enum TextTrackKind { "subtitles",  "captions",  "descriptions",  "chapters",  "metadata" };
-
-[Exposed=Window]
-interface TextTrack : EventTarget {
-  readonly attribute TextTrackKind kind;
-  readonly attribute DOMString label;
-  readonly attribute DOMString language;
-
-  readonly attribute DOMString id;
-  readonly attribute DOMString inBandMetadataTrackDispatchType;
-
-  attribute TextTrackMode mode;
-
-  readonly attribute TextTrackCueList? cues;
-  readonly attribute TextTrackCueList? activeCues;
-
-  void addCue(TextTrackCue cue);
-  void removeCue(TextTrackCue cue);
-
-  attribute EventHandler oncuechange;
-};
-
-[Exposed=Window]
-interface TextTrackCueList {
-  readonly attribute unsigned long length;
-  getter TextTrackCue (unsigned long index);
-  TextTrackCue? getCueById(DOMString id);
-};
-
-[Exposed=Window]
-interface TextTrackCue : EventTarget {
-  readonly attribute TextTrack? track;
-
-  attribute DOMString id;
-  attribute double startTime;
-  attribute double endTime;
-  attribute boolean pauseOnExit;
-
-  attribute EventHandler onenter;
-  attribute EventHandler onexit;
-};
-
-[Exposed=Window]
-interface TimeRanges {
-  readonly attribute unsigned long length;
-  double start(unsigned long index);
-  double end(unsigned long index);
-};
-
-[Exposed=Window,
- Constructor(DOMString type, optional TrackEventInit eventInitDict = {})]
-interface TrackEvent : Event {
-  readonly attribute (VideoTrack or AudioTrack or TextTrack)? track;
-};
-
-dictionary TrackEventInit : EventInit {
-  (VideoTrack or AudioTrack or TextTrack)? track = null;
-};
-
-[Exposed=Window,
- HTMLConstructor]
-interface HTMLMapElement : HTMLElement {
-  [CEReactions] attribute DOMString name;
-  [SameObject] readonly attribute HTMLCollection areas;
-};
-
-[Exposed=Window,
- HTMLConstructor]
-interface HTMLAreaElement : HTMLElement {
-  [CEReactions] attribute DOMString alt;
-  [CEReactions] attribute DOMString coords;
-  [CEReactions] attribute DOMString shape;
-  [CEReactions] attribute DOMString target;
-  [CEReactions] attribute DOMString download;
-  [CEReactions] attribute USVString ping;
-  [CEReactions] attribute DOMString rel;
-  [SameObject, PutForwards=value] readonly attribute DOMTokenList relList;
-  [CEReactions] attribute DOMString referrerPolicy;
-};
-HTMLAreaElement includes HTMLHyperlinkElementUtils;
-
-[Exposed=Window,
- HTMLConstructor]
-interface HTMLTableElement : HTMLElement {
-  [CEReactions] attribute HTMLTableCaptionElement? caption;
-  HTMLTableCaptionElement createCaption();
-  [CEReactions] void deleteCaption();
-
-  [CEReactions] attribute HTMLTableSectionElement? tHead;
-  HTMLTableSectionElement createTHead();
-  [CEReactions] void deleteTHead();
-
-  [CEReactions] attribute HTMLTableSectionElement? tFoot;
-  HTMLTableSectionElement createTFoot();
-  [CEReactions] void deleteTFoot();
-
-  [SameObject] readonly attribute HTMLCollection tBodies;
-  HTMLTableSectionElement createTBody();
-
-  [SameObject] readonly attribute HTMLCollection rows;
-  HTMLTableRowElement insertRow(optional long index = -1);
-  [CEReactions] void deleteRow(long index);
-};
-
-[Exposed=Window,
- HTMLConstructor]
-interface HTMLTableCaptionElement : HTMLElement {};
-
-[Exposed=Window,
- HTMLConstructor]
-interface HTMLTableColElement : HTMLElement {
-  [CEReactions] attribute unsigned long span;
-};
-
-[Exposed=Window,
- HTMLConstructor]
-interface HTMLTableSectionElement : HTMLElement {
-  [SameObject] readonly attribute HTMLCollection rows;
-  HTMLTableRowElement insertRow(optional long index = -1);
-  [CEReactions] void deleteRow(long index);
-};
-
-[Exposed=Window,
- HTMLConstructor]
-interface HTMLTableRowElement : HTMLElement {
-  readonly attribute long rowIndex;
-  readonly attribute long sectionRowIndex;
-  [SameObject] readonly attribute HTMLCollection cells;
-  HTMLTableCellElement insertCell(optional long index = -1);
-  [CEReactions] void deleteCell(long index);
-};
-
-[Exposed=Window,
- HTMLConstructor]
-interface HTMLTableCellElement : HTMLElement {
-  [CEReactions] attribute unsigned long colSpan;
-  [CEReactions] attribute unsigned long rowSpan;
-  [CEReactions] attribute DOMString headers;
-  readonly attribute long cellIndex;
-
-  [CEReactions] attribute DOMString scope; // only conforming for th elements
-  [CEReactions] attribute DOMString abbr;  // only conforming for th elements
-};
-
-[Exposed=Window,
- OverrideBuiltins,
- LegacyUnenumerableNamedProperties,
- HTMLConstructor]
-interface HTMLFormElement : HTMLElement {
-  [CEReactions] attribute DOMString acceptCharset;
-  [CEReactions] attribute USVString action;
-  [CEReactions] attribute DOMString autocomplete;
-  [CEReactions] attribute DOMString enctype;
-  [CEReactions] attribute DOMString encoding;
-  [CEReactions] attribute DOMString method;
-  [CEReactions] attribute DOMString name;
-  [CEReactions] attribute boolean noValidate;
-  [CEReactions] attribute DOMString target;
-
-  [SameObject] readonly attribute HTMLFormControlsCollection elements;
-  readonly attribute unsigned long length;
-  getter Element (unsigned long index);
-  getter (RadioNodeList or Element) (DOMString name);
-
-  void submit();
-  [CEReactions] void reset();
-  boolean checkValidity();
-  boolean reportValidity();
-};
-
-[Exposed=Window,
- HTMLConstructor]
-interface HTMLLabelElement : HTMLElement {
-  readonly attribute HTMLFormElement? form;
-  [CEReactions] attribute DOMString htmlFor;
-  readonly attribute HTMLElement? control;
-};
-
-[Exposed=Window,
- HTMLConstructor]
-interface HTMLInputElement : HTMLElement {
-  [CEReactions] attribute DOMString accept;
-  [CEReactions] attribute DOMString alt;
-  [CEReactions] attribute DOMString autocomplete;
-  [CEReactions] attribute boolean autofocus;
-  [CEReactions] attribute boolean defaultChecked;
-  attribute boolean checked;
-  [CEReactions] attribute DOMString dirName;
-  [CEReactions] attribute boolean disabled;
-  readonly attribute HTMLFormElement? form;
-  attribute FileList? files;
-  [CEReactions] attribute USVString formAction;
-  [CEReactions] attribute DOMString formEnctype;
-  [CEReactions] attribute DOMString formMethod;
-  [CEReactions] attribute boolean formNoValidate;
-  [CEReactions] attribute DOMString formTarget;
-  [CEReactions] attribute unsigned long height;
-  attribute boolean indeterminate;
-  readonly attribute HTMLElement? list;
-  [CEReactions] attribute DOMString max;
-  [CEReactions] attribute long maxLength;
-  [CEReactions] attribute DOMString min;
-  [CEReactions] attribute long minLength;
-  [CEReactions] attribute boolean multiple;
-  [CEReactions] attribute DOMString name;
-  [CEReactions] attribute DOMString pattern;
-  [CEReactions] attribute DOMString placeholder;
-  [CEReactions] attribute boolean readOnly;
-  [CEReactions] attribute boolean required;
-  [CEReactions] attribute unsigned long size;
-  [CEReactions] attribute USVString src;
-  [CEReactions] attribute DOMString step;
-  [CEReactions] attribute DOMString type;
-  [CEReactions] attribute DOMString defaultValue;
-  [CEReactions] attribute [TreatNullAs=EmptyString] DOMString value;
-  attribute object? valueAsDate;
-  attribute unrestricted double valueAsNumber;
-  [CEReactions] attribute unsigned long width;
-
-  void stepUp(optional long n = 1);
-  void stepDown(optional long n = 1);
-
-  readonly attribute boolean willValidate;
-  readonly attribute ValidityState validity;
-  readonly attribute DOMString validationMessage;
-  boolean checkValidity();
-  boolean reportValidity();
-  void setCustomValidity(DOMString error);
-
-  readonly attribute NodeList? labels;
-
-  void select();
-  attribute unsigned long? selectionStart;
-  attribute unsigned long? selectionEnd;
-  attribute DOMString? selectionDirection;
-  void setRangeText(DOMString replacement);
-  void setRangeText(DOMString replacement, unsigned long start, unsigned long end, optional SelectionMode selectionMode = "preserve");
-  void setSelectionRange(unsigned long start, unsigned long end, optional DOMString direction);
-};
-
-[Exposed=Window,
- HTMLConstructor]
-interface HTMLButtonElement : HTMLElement {
-  [CEReactions] attribute boolean autofocus;
-  [CEReactions] attribute boolean disabled;
-  readonly attribute HTMLFormElement? form;
-  [CEReactions] attribute USVString formAction;
-  [CEReactions] attribute DOMString formEnctype;
-  [CEReactions] attribute DOMString formMethod;
-  [CEReactions] attribute boolean formNoValidate;
-  [CEReactions] attribute DOMString formTarget;
-  [CEReactions] attribute DOMString name;
-  [CEReactions] attribute DOMString type;
-  [CEReactions] attribute DOMString value;
-
-  readonly attribute boolean willValidate;
-  readonly attribute ValidityState validity;
-  readonly attribute DOMString validationMessage;
-  boolean checkValidity();
-  boolean reportValidity();
-  void setCustomValidity(DOMString error);
-
-  readonly attribute NodeList labels;
-};
-
-[Exposed=Window,
- HTMLConstructor]
-interface HTMLSelectElement : HTMLElement {
-  [CEReactions] attribute DOMString autocomplete;
-  [CEReactions] attribute boolean autofocus;
-  [CEReactions] attribute boolean disabled;
-  readonly attribute HTMLFormElement? form;
-  [CEReactions] attribute boolean multiple;
-  [CEReactions] attribute DOMString name;
-  [CEReactions] attribute boolean required;
-  [CEReactions] attribute unsigned long size;
-
-  readonly attribute DOMString type;
-
-  [SameObject] readonly attribute HTMLOptionsCollection options;
-  [CEReactions] attribute unsigned long length;
-  getter Element? item(unsigned long index);
-  HTMLOptionElement? namedItem(DOMString name);
-  [CEReactions] void add((HTMLOptionElement or HTMLOptGroupElement) element, optional (HTMLElement or long)? before = null);
-  [CEReactions] void remove(); // ChildNode overload
-  [CEReactions] void remove(long index);
-  [CEReactions] setter void (unsigned long index, HTMLOptionElement? option);
-
-  [SameObject] readonly attribute HTMLCollection selectedOptions;
-  attribute long selectedIndex;
-  attribute DOMString value;
-
-  readonly attribute boolean willValidate;
-  readonly attribute ValidityState validity;
-  readonly attribute DOMString validationMessage;
-  boolean checkValidity();
-  boolean reportValidity();
-  void setCustomValidity(DOMString error);
-
-  readonly attribute NodeList labels;
-};
-
-[Exposed=Window,
- HTMLConstructor]
-interface HTMLDataListElement : HTMLElement {
-  [SameObject] readonly attribute HTMLCollection options;
-};
-
-[Exposed=Window,
- HTMLConstructor]
-interface HTMLOptGroupElement : HTMLElement {
-  [CEReactions] attribute boolean disabled;
-  [CEReactions] attribute DOMString label;
-};
-
-[Exposed=Window,
- HTMLConstructor,
- NamedConstructor=Option(optional DOMString text = "", optional DOMString value, optional boolean defaultSelected = false, optional boolean selected = false)]
-interface HTMLOptionElement : HTMLElement {
-  [CEReactions] attribute boolean disabled;
-  readonly attribute HTMLFormElement? form;
-  [CEReactions] attribute DOMString label;
-  [CEReactions] attribute boolean defaultSelected;
-  attribute boolean selected;
-  [CEReactions] attribute DOMString value;
-
-  [CEReactions] attribute DOMString text;
-  readonly attribute long index;
-};
-
-[Exposed=Window,
- HTMLConstructor]
-interface HTMLTextAreaElement : HTMLElement {
-  [CEReactions] attribute DOMString autocomplete;
-  [CEReactions] attribute boolean autofocus;
-  [CEReactions] attribute unsigned long cols;
-  [CEReactions] attribute DOMString dirName;
-  [CEReactions] attribute boolean disabled;
-  readonly attribute HTMLFormElement? form;
-  [CEReactions] attribute long maxLength;
-  [CEReactions] attribute long minLength;
-  [CEReactions] attribute DOMString name;
-  [CEReactions] attribute DOMString placeholder;
-  [CEReactions] attribute boolean readOnly;
-  [CEReactions] attribute boolean required;
-  [CEReactions] attribute unsigned long rows;
-  [CEReactions] attribute DOMString wrap;
-
-  readonly attribute DOMString type;
-  [CEReactions] attribute DOMString defaultValue;
-  [CEReactions] attribute [TreatNullAs=EmptyString] DOMString value;
-  readonly attribute unsigned long textLength;
-
-  readonly attribute boolean willValidate;
-  readonly attribute ValidityState validity;
-  readonly attribute DOMString validationMessage;
-  boolean checkValidity();
-  boolean reportValidity();
-  void setCustomValidity(DOMString error);
-
-  readonly attribute NodeList labels;
-
-  void select();
-  attribute unsigned long selectionStart;
-  attribute unsigned long selectionEnd;
-  attribute DOMString selectionDirection;
-  void setRangeText(DOMString replacement);
-  void setRangeText(DOMString replacement, unsigned long start, unsigned long end, optional SelectionMode selectionMode = "preserve");
-  void setSelectionRange(unsigned long start, unsigned long end, optional DOMString direction);
-};
-
-[Exposed=Window,
- HTMLConstructor]
-interface HTMLOutputElement : HTMLElement {
-  [SameObject, PutForwards=value] readonly attribute DOMTokenList htmlFor;
-  readonly attribute HTMLFormElement? form;
-  [CEReactions] attribute DOMString name;
-
-  readonly attribute DOMString type;
-  [CEReactions] attribute DOMString defaultValue;
-  [CEReactions] attribute DOMString value;
-
-  readonly attribute boolean willValidate;
-  readonly attribute ValidityState validity;
-  readonly attribute DOMString validationMessage;
-  boolean checkValidity();
-  boolean reportValidity();
-  void setCustomValidity(DOMString error);
-
-  readonly attribute NodeList labels;
-};
-
-[Exposed=Window,
- HTMLConstructor]
-interface HTMLProgressElement : HTMLElement {
-  [CEReactions] attribute double value;
-  [CEReactions] attribute double max;
-  readonly attribute double position;
-  readonly attribute NodeList labels;
-};
-
-[Exposed=Window,
- HTMLConstructor]
-interface HTMLMeterElement : HTMLElement {
-  [CEReactions] attribute double value;
-  [CEReactions] attribute double min;
-  [CEReactions] attribute double max;
-  [CEReactions] attribute double low;
-  [CEReactions] attribute double high;
-  [CEReactions] attribute double optimum;
-  readonly attribute NodeList labels;
-};
-
-[Exposed=Window,
- HTMLConstructor]
-interface HTMLFieldSetElement : HTMLElement {
-  [CEReactions] attribute boolean disabled;
-  readonly attribute HTMLFormElement? form;
-  [CEReactions] attribute DOMString name;
-
-  readonly attribute DOMString type;
-
-  [SameObject] readonly attribute HTMLCollection elements;
-
-  readonly attribute boolean willValidate;
-  [SameObject] readonly attribute ValidityState validity;
-  readonly attribute DOMString validationMessage;
-  boolean checkValidity();
-  boolean reportValidity();
-  void setCustomValidity(DOMString error);
-};
-
-[Exposed=Window,
- HTMLConstructor]
-interface HTMLLegendElement : HTMLElement {
-  readonly attribute HTMLFormElement? form;
-};
-
-enum SelectionMode {
-  "select",
-  "start",
-  "end",
-  "preserve" // default
-};
-
-[Exposed=Window]
-interface ValidityState {
-  readonly attribute boolean valueMissing;
-  readonly attribute boolean typeMismatch;
-  readonly attribute boolean patternMismatch;
-  readonly attribute boolean tooLong;
-  readonly attribute boolean tooShort;
-  readonly attribute boolean rangeUnderflow;
-  readonly attribute boolean rangeOverflow;
-  readonly attribute boolean stepMismatch;
-  readonly attribute boolean badInput;
-  readonly attribute boolean customError;
-  readonly attribute boolean valid;
-};
-
-[Exposed=Window,
- HTMLConstructor]
-interface HTMLDetailsElement : HTMLElement {
-  [CEReactions] attribute boolean open;
-};
-
-[Exposed=Window,
- HTMLConstructor]
-interface HTMLDialogElement : HTMLElement {
-  [CEReactions] attribute boolean open;
-  attribute DOMString returnValue;
-  [CEReactions] void show();
-  [CEReactions] void showModal();
-  [CEReactions] void close(optional DOMString returnValue);
-};
-
-[Exposed=Window,
- HTMLConstructor]
-interface HTMLScriptElement : HTMLElement {
-  [CEReactions] attribute USVString src;
-  [CEReactions] attribute DOMString type;
-  [CEReactions] attribute boolean noModule;
-  [CEReactions] attribute boolean async;
-  [CEReactions] attribute boolean defer;
-  [CEReactions] attribute DOMString? crossOrigin;
-  [CEReactions] attribute DOMString text;
-  [CEReactions] attribute DOMString integrity;
-
-};
-
-[Exposed=Window,
- HTMLConstructor]
-interface HTMLTemplateElement : HTMLElement {
-  readonly attribute DocumentFragment content;
-};
-
-[Exposed=Window,
- HTMLConstructor]
-interface HTMLSlotElement : HTMLElement {
-  [CEReactions] attribute DOMString name;
-  sequence<Node> assignedNodes(optional AssignedNodesOptions options = {});
-  sequence<Element> assignedElements(optional AssignedNodesOptions options = {});
-};
-
-dictionary AssignedNodesOptions {
-  boolean flatten = false;
-};
-
-typedef (CanvasRenderingContext2D or ImageBitmapRenderingContext or WebGLRenderingContext) RenderingContext;
-
-[Exposed=Window,
- HTMLConstructor]
-interface HTMLCanvasElement : HTMLElement {
-  [CEReactions] attribute unsigned long width;
-  [CEReactions] attribute unsigned long height;
-
-  RenderingContext? getContext(DOMString contextId, optional any options = null);
-
-  USVString toDataURL(optional DOMString type, optional any quality);
-  void toBlob(BlobCallback _callback, optional DOMString type, optional any quality);
-  OffscreenCanvas transferControlToOffscreen();
-};
-
-callback BlobCallback = void (Blob? blob);
-
-typedef (HTMLImageElement or
-         SVGImageElement) HTMLOrSVGImageElement;
-
-typedef (HTMLOrSVGImageElement or
-         HTMLVideoElement or
-         HTMLCanvasElement or
-         ImageBitmap or
-         OffscreenCanvas) CanvasImageSource;
-
-enum CanvasFillRule { "nonzero", "evenodd" };
-
-dictionary CanvasRenderingContext2DSettings {
-  boolean alpha = true;
-};
-
-enum ImageSmoothingQuality { "low", "medium", "high" };
-
-[Exposed=Window]
-interface CanvasRenderingContext2D {
-  // back-reference to the canvas
-  readonly attribute HTMLCanvasElement canvas;
-};
-CanvasRenderingContext2D includes CanvasState;
-CanvasRenderingContext2D includes CanvasTransform;
-CanvasRenderingContext2D includes CanvasCompositing;
-CanvasRenderingContext2D includes CanvasImageSmoothing;
-CanvasRenderingContext2D includes CanvasFillStrokeStyles;
-CanvasRenderingContext2D includes CanvasShadowStyles;
-CanvasRenderingContext2D includes CanvasFilters;
-CanvasRenderingContext2D includes CanvasRect;
-CanvasRenderingContext2D includes CanvasDrawPath;
-CanvasRenderingContext2D includes CanvasUserInterface;
-CanvasRenderingContext2D includes CanvasText;
-CanvasRenderingContext2D includes CanvasDrawImage;
-CanvasRenderingContext2D includes CanvasImageData;
-CanvasRenderingContext2D includes CanvasPathDrawingStyles;
-CanvasRenderingContext2D includes CanvasTextDrawingStyles;
-CanvasRenderingContext2D includes CanvasPath;
-
-interface mixin CanvasState {
-  // state
-  void save(); // push state on state stack
-  void restore(); // pop state stack and restore state
-};
-
-interface mixin CanvasTransform {
-  // transformations (default transform is the identity matrix)
-  void scale(unrestricted double x, unrestricted double y);
-  void rotate(unrestricted double angle);
-  void translate(unrestricted double x, unrestricted double y);
-  void transform(unrestricted double a, unrestricted double b, unrestricted double c, unrestricted double d, unrestricted double e, unrestricted double f);
-
-  [NewObject] DOMMatrix getTransform();
-  void setTransform(unrestricted double a, unrestricted double b, unrestricted double c, unrestricted double d, unrestricted double e, unrestricted double f);
-  void setTransform(optional DOMMatrix2DInit transform = {});
-  void resetTransform();
-
-};
-
-interface mixin CanvasCompositing {
-  // compositing
-  attribute unrestricted double globalAlpha; // (default 1.0)
-  attribute DOMString globalCompositeOperation; // (default source-over)
-};
-
-interface mixin CanvasImageSmoothing {
-  // image smoothing
-  attribute boolean imageSmoothingEnabled; // (default true)
-  attribute ImageSmoothingQuality imageSmoothingQuality; // (default low)
-
-};
-
-interface mixin CanvasFillStrokeStyles {
-  // colors and styles (see also the CanvasPathDrawingStyles and CanvasTextDrawingStyles interfaces)
-  attribute (DOMString or CanvasGradient or CanvasPattern) strokeStyle; // (default black)
-  attribute (DOMString or CanvasGradient or CanvasPattern) fillStyle; // (default black)
-  CanvasGradient createLinearGradient(double x0, double y0, double x1, double y1);
-  CanvasGradient createRadialGradient(double x0, double y0, double r0, double x1, double y1, double r1);
-  CanvasPattern? createPattern(CanvasImageSource image, [TreatNullAs=EmptyString] DOMString repetition);
-
-};
-
-interface mixin CanvasShadowStyles {
-  // shadows
-  attribute unrestricted double shadowOffsetX; // (default 0)
-  attribute unrestricted double shadowOffsetY; // (default 0)
-  attribute unrestricted double shadowBlur; // (default 0)
-  attribute DOMString shadowColor; // (default transparent black)
-};
-
-interface mixin CanvasFilters {
-  // filters
-  attribute DOMString filter; // (default "none")
-};
-
-interface mixin CanvasRect {
-  // rects
-  void clearRect(unrestricted double x, unrestricted double y, unrestricted double w, unrestricted double h);
-  void fillRect(unrestricted double x, unrestricted double y, unrestricted double w, unrestricted double h);
-  void strokeRect(unrestricted double x, unrestricted double y, unrestricted double w, unrestricted double h);
-};
-
-interface mixin CanvasDrawPath {
-  // path API (see also CanvasPath)
-  void beginPath();
-  void fill(optional CanvasFillRule fillRule = "nonzero");
-  void fill(Path2D path, optional CanvasFillRule fillRule = "nonzero");
-  void stroke();
-  void stroke(Path2D path);
-  void clip(optional CanvasFillRule fillRule = "nonzero");
-  void clip(Path2D path, optional CanvasFillRule fillRule = "nonzero");
-  void resetClip();
-  boolean isPointInPath(unrestricted double x, unrestricted double y, optional CanvasFillRule fillRule = "nonzero");
-  boolean isPointInPath(Path2D path, unrestricted double x, unrestricted double y, optional CanvasFillRule fillRule = "nonzero");
-  boolean isPointInStroke(unrestricted double x, unrestricted double y);
-  boolean isPointInStroke(Path2D path, unrestricted double x, unrestricted double y);
-};
-
-interface mixin CanvasUserInterface {
-  void drawFocusIfNeeded(Element element);
-  void drawFocusIfNeeded(Path2D path, Element element);
-  void scrollPathIntoView();
-  void scrollPathIntoView(Path2D path);
-};
-
-interface mixin CanvasText {
-  // text (see also the CanvasPathDrawingStyles and CanvasTextDrawingStyles interfaces)
-  void fillText(DOMString text, unrestricted double x, unrestricted double y, optional unrestricted double maxWidth);
-  void strokeText(DOMString text, unrestricted double x, unrestricted double y, optional unrestricted double maxWidth);
-  TextMetrics measureText(DOMString text);
-};
-
-interface mixin CanvasDrawImage {
-  // drawing images
-  void drawImage(CanvasImageSource image, unrestricted double dx, unrestricted double dy);
-  void drawImage(CanvasImageSource image, unrestricted double dx, unrestricted double dy, unrestricted double dw, unrestricted double dh);
-  void drawImage(CanvasImageSource image, unrestricted double sx, unrestricted double sy, unrestricted double sw, unrestricted double sh, unrestricted double dx, unrestricted double dy, unrestricted double dw, unrestricted double dh);
-};
-
-interface mixin CanvasImageData {
-  // pixel manipulation
-  ImageData createImageData(long sw, long sh);
-  ImageData createImageData(ImageData imagedata);
-  ImageData getImageData(long sx, long sy, long sw, long sh);
-  void putImageData(ImageData imagedata, long dx, long dy);
-  void putImageData(ImageData imagedata, long dx, long dy, long dirtyX, long dirtyY, long dirtyWidth, long dirtyHeight);
-};
-
-enum CanvasLineCap { "butt", "round", "square" };
-enum CanvasLineJoin { "round", "bevel", "miter" };
-enum CanvasTextAlign { "start", "end", "left", "right", "center" };
-enum CanvasTextBaseline { "top", "hanging", "middle", "alphabetic", "ideographic", "bottom" };
-enum CanvasDirection { "ltr", "rtl", "inherit" };
-
-interface mixin CanvasPathDrawingStyles {
-  // line caps/joins
-  attribute unrestricted double lineWidth; // (default 1)
-  attribute CanvasLineCap lineCap; // (default "butt")
-  attribute CanvasLineJoin lineJoin; // (default "miter")
-  attribute unrestricted double miterLimit; // (default 10)
-
-  // dashed lines
-  void setLineDash(sequence<unrestricted double> segments); // default empty
-  sequence<unrestricted double> getLineDash();
-  attribute unrestricted double lineDashOffset;
-};
-
-interface mixin CanvasTextDrawingStyles {
-  // text
-  attribute DOMString font; // (default 10px sans-serif)
-  attribute CanvasTextAlign textAlign; // (default: "start")
-  attribute CanvasTextBaseline textBaseline; // (default: "alphabetic")
-  attribute CanvasDirection direction; // (default: "inherit")
-};
-
-interface mixin CanvasPath {
-  // shared path API methods
-  void closePath();
-  void moveTo(unrestricted double x, unrestricted double y);
-  void lineTo(unrestricted double x, unrestricted double y);
-  void quadraticCurveTo(unrestricted double cpx, unrestricted double cpy, unrestricted double x, unrestricted double y);
-  void bezierCurveTo(unrestricted double cp1x, unrestricted double cp1y, unrestricted double cp2x, unrestricted double cp2y, unrestricted double x, unrestricted double y);
-  void arcTo(unrestricted double x1, unrestricted double y1, unrestricted double x2, unrestricted double y2, unrestricted double radius);
-  void rect(unrestricted double x, unrestricted double y, unrestricted double w, unrestricted double h);
-  void arc(unrestricted double x, unrestricted double y, unrestricted double radius, unrestricted double startAngle, unrestricted double endAngle, optional boolean anticlockwise = false);
-  void ellipse(unrestricted double x, unrestricted double y, unrestricted double radiusX, unrestricted double radiusY, unrestricted double rotation, unrestricted double startAngle, unrestricted double endAngle, optional boolean anticlockwise = false);
-};
-
-[Exposed=(Window,Worker)]
-interface CanvasGradient {
-  // opaque object
-  void addColorStop(double offset, DOMString color);
-};
-
-[Exposed=(Window,Worker)]
-interface CanvasPattern {
-  // opaque object
-  void setTransform(optional DOMMatrix2DInit transform = {});
-};
-
-[Exposed=Window]
-interface TextMetrics {
-  // x-direction
-  readonly attribute double width; // advance width
-  readonly attribute double actualBoundingBoxLeft;
-  readonly attribute double actualBoundingBoxRight;
-
-  // y-direction
-  readonly attribute double fontBoundingBoxAscent;
-  readonly attribute double fontBoundingBoxDescent;
-  readonly attribute double actualBoundingBoxAscent;
-  readonly attribute double actualBoundingBoxDescent;
-  readonly attribute double emHeightAscent;
-  readonly attribute double emHeightDescent;
-  readonly attribute double hangingBaseline;
-  readonly attribute double alphabeticBaseline;
-  readonly attribute double ideographicBaseline;
-};
-
-[Constructor(unsigned long sw, unsigned long sh),
- Constructor(Uint8ClampedArray data, unsigned long sw, optional unsigned long sh),
- Exposed=(Window,Worker),
- Serializable]
-interface ImageData {
-  readonly attribute unsigned long width;
-  readonly attribute unsigned long height;
-  readonly attribute Uint8ClampedArray data;
-};
-
-[Constructor(optional (Path2D or DOMString) path),
- Exposed=(Window,Worker)]
-interface Path2D {
-  void addPath(Path2D path, optional DOMMatrix2DInit transform = {});
-};
-Path2D includes CanvasPath;
-
-[Exposed=Window]
-interface ImageBitmapRenderingContext {
-  readonly attribute HTMLCanvasElement canvas;
-  void transferFromImageBitmap(ImageBitmap? bitmap);
-};
-
-dictionary ImageBitmapRenderingContextSettings {
-  boolean alpha = true;
-};
-
-typedef (OffscreenCanvasRenderingContext2D or
-        WebGLRenderingContext) OffscreenRenderingContext;
-
-dictionary ImageEncodeOptions {
-  DOMString type = "image/png";
-  unrestricted double quality = 1.0;
-};
-
-enum OffscreenRenderingContextId { "2d", "webgl" };
-
-[Constructor([EnforceRange] unsigned long long width, [EnforceRange] unsigned long long height), Exposed=(Window,Worker), Transferable]
-interface OffscreenCanvas : EventTarget {
-  attribute unsigned long long width;
-  attribute unsigned long long height;
-
-  OffscreenRenderingContext? getContext(OffscreenRenderingContextId contextId, optional any options = null);
-  ImageBitmap transferToImageBitmap();
-  Promise<Blob> convertToBlob(optional ImageEncodeOptions options = {});
-};
-
-[Exposed=(Window,Worker)]
-interface OffscreenCanvasRenderingContext2D {
-  void commit();
-  readonly attribute OffscreenCanvas canvas;
-};
-
-OffscreenCanvasRenderingContext2D includes CanvasState;
-OffscreenCanvasRenderingContext2D includes CanvasTransform;
-OffscreenCanvasRenderingContext2D includes CanvasCompositing;
-OffscreenCanvasRenderingContext2D includes CanvasImageSmoothing;
-OffscreenCanvasRenderingContext2D includes CanvasFillStrokeStyles;
-OffscreenCanvasRenderingContext2D includes CanvasShadowStyles;
-OffscreenCanvasRenderingContext2D includes CanvasFilters;
-OffscreenCanvasRenderingContext2D includes CanvasRect;
-OffscreenCanvasRenderingContext2D includes CanvasDrawPath;
-OffscreenCanvasRenderingContext2D includes CanvasDrawImage;
-OffscreenCanvasRenderingContext2D includes CanvasImageData;
-OffscreenCanvasRenderingContext2D includes CanvasPathDrawingStyles;
-OffscreenCanvasRenderingContext2D includes CanvasPath;
-
-[Exposed=Window]
-interface CustomElementRegistry {
-  [CEReactions] void define(DOMString name, Function constructor, optional ElementDefinitionOptions options = {});
-  any get(DOMString name);
-  Promise<void> whenDefined(DOMString name);
-  [CEReactions] void upgrade(Node root);
-};
-
-dictionary ElementDefinitionOptions {
-  DOMString extends;
-};
-
-dictionary FocusOptions {
-  boolean preventScroll = false;
-};
-
-interface mixin ElementContentEditable {
-  [CEReactions] attribute DOMString contentEditable;
-  readonly attribute boolean isContentEditable;
-  [CEReactions] attribute DOMString inputMode;
-};
-
-[Exposed=Window,
- Constructor]
-interface DataTransfer {
-  attribute DOMString dropEffect;
-  attribute DOMString effectAllowed;
-
-  [SameObject] readonly attribute DataTransferItemList items;
-
-  void setDragImage(Element image, long x, long y);
-
-  /* old interface */
-  readonly attribute FrozenArray<DOMString> types;
-  DOMString getData(DOMString format);
-  void setData(DOMString format, DOMString data);
-  void clearData(optional DOMString format);
-  [SameObject] readonly attribute FileList files;
-};
-
-[Exposed=Window]
-interface DataTransferItemList {
-  readonly attribute unsigned long length;
-  getter DataTransferItem (unsigned long index);
-  DataTransferItem? add(DOMString data, DOMString type);
-  DataTransferItem? add(File data);
-  void remove(unsigned long index);
-  void clear();
-};
-
-[Exposed=Window]
-interface DataTransferItem {
-  readonly attribute DOMString kind;
-  readonly attribute DOMString type;
-  void getAsString(FunctionStringCallback? _callback);
-  File? getAsFile();
-};
-
-callback FunctionStringCallback = void (DOMString data);
-
-[Exposed=Window,
- Constructor(DOMString type, optional DragEventInit eventInitDict = {})]
-interface DragEvent : MouseEvent {
-  readonly attribute DataTransfer? dataTransfer;
-};
-
-dictionary DragEventInit : MouseEventInit {
-  DataTransfer? dataTransfer = null;
-};
-
-[Global=Window,
- Exposed=Window,
- LegacyUnenumerableNamedProperties]
-interface Window : EventTarget {
-  // the current browsing context
-  [Unforgeable] readonly attribute WindowProxy window;
-  [Replaceable] readonly attribute WindowProxy self;
-  [Unforgeable] readonly attribute Document document;
-  attribute DOMString name;
-  [PutForwards=href, Unforgeable] readonly attribute Location location;
-  readonly attribute History history;
-  readonly attribute CustomElementRegistry customElements;
-  [Replaceable] readonly attribute BarProp locationbar;
-  [Replaceable] readonly attribute BarProp menubar;
-  [Replaceable] readonly attribute BarProp personalbar;
-  [Replaceable] readonly attribute BarProp scrollbars;
-  [Replaceable] readonly attribute BarProp statusbar;
-  [Replaceable] readonly attribute BarProp toolbar;
-  attribute DOMString status;
-  void close();
-  readonly attribute boolean closed;
-  void stop();
-  void focus();
-  void blur();
-
-  // other browsing contexts
-  [Replaceable] readonly attribute WindowProxy frames;
-  [Replaceable] readonly attribute unsigned long length;
-  [Unforgeable] readonly attribute WindowProxy? top;
-  attribute any opener;
-  [Replaceable] readonly attribute WindowProxy? parent;
-  readonly attribute Element? frameElement;
-  WindowProxy? open(optional USVString url = "about:blank", optional DOMString target = "_blank", optional [TreatNullAs=EmptyString] DOMString features = "");
-  getter object (DOMString name);
-  // Since this is the global object, the IDL named getter adds a NamedPropertiesObject exotic
-  // object on the prototype chain. Indeed, this does not make the global object an exotic object.
-  // Indexed access is taken care of by the WindowProxy exotic object.
-
-  // the user agent
-  readonly attribute Navigator navigator;
-  readonly attribute ApplicationCache applicationCache;
-
-  // user prompts
-  void alert();
-  void alert(DOMString message);
-  boolean confirm(optional DOMString message = "");
-  DOMString? prompt(optional DOMString message = "", optional DOMString default = "");
-  void print();
-
-  unsigned long requestAnimationFrame(FrameRequestCallback callback);
-  void cancelAnimationFrame(unsigned long handle);
-
-  void postMessage(any message, USVString targetOrigin, optional sequence<object> transfer = []);
-};
-Window includes GlobalEventHandlers;
-Window includes WindowEventHandlers;
-
-callback FrameRequestCallback = void (DOMHighResTimeStamp time);
-
-[Exposed=Window]
-interface BarProp {
-  readonly attribute boolean visible;
-};
-
-enum ScrollRestoration { "auto", "manual" };
-
-[Exposed=Window]
-interface History {
-  readonly attribute unsigned long length;
-  attribute ScrollRestoration scrollRestoration;
-  readonly attribute any state;
-  void go(optional long delta = 0);
-  void back();
-  void forward();
-  void pushState(any data, DOMString title, optional USVString? url = null);
-  void replaceState(any data, DOMString title, optional USVString? url = null);
-};
-
-[Exposed=Window]
-interface Location { // but see also additional creation steps and overridden internal methods
-  [Unforgeable] stringifier attribute USVString href;
-  [Unforgeable] readonly attribute USVString origin;
-  [Unforgeable] attribute USVString protocol;
-  [Unforgeable] attribute USVString host;
-  [Unforgeable] attribute USVString hostname;
-  [Unforgeable] attribute USVString port;
-  [Unforgeable] attribute USVString pathname;
-  [Unforgeable] attribute USVString search;
-  [Unforgeable] attribute USVString hash;
-
-  [Unforgeable] void assign(USVString url);
-  [Unforgeable] void replace(USVString url);
-  [Unforgeable] void reload();
-
-  [Unforgeable, SameObject] readonly attribute DOMStringList ancestorOrigins;
-};
-
-[Exposed=Window,
- Constructor(DOMString type, optional PopStateEventInit eventInitDict = {})]
-interface PopStateEvent : Event {
-  readonly attribute any state;
-};
-
-dictionary PopStateEventInit : EventInit {
-  any state = null;
-};
-
-[Exposed=Window,
- Constructor(DOMString type, optional HashChangeEventInit eventInitDict = {})]
-interface HashChangeEvent : Event {
-  readonly attribute USVString oldURL;
-  readonly attribute USVString newURL;
-};
-
-dictionary HashChangeEventInit : EventInit {
-  USVString oldURL = "";
-  USVString newURL = "";
-};
-
-[Exposed=Window,
- Constructor(DOMString type, optional PageTransitionEventInit eventInitDict = {})]
-interface PageTransitionEvent : Event {
-  readonly attribute boolean persisted;
-};
-
-dictionary PageTransitionEventInit : EventInit {
-  boolean persisted = false;
-};
-
-[Exposed=Window]
-interface BeforeUnloadEvent : Event {
-  attribute DOMString returnValue;
-};
-
-[Exposed=Window]
-interface ApplicationCache : EventTarget {
-
-  // update status
-  const unsigned short UNCACHED = 0;
-  const unsigned short IDLE = 1;
-  const unsigned short CHECKING = 2;
-  const unsigned short DOWNLOADING = 3;
-  const unsigned short UPDATEREADY = 4;
-  const unsigned short OBSOLETE = 5;
-  readonly attribute unsigned short status;
-
-  // updates
-  void update();
-  void abort();
-  void swapCache();
-
-  // events
-  attribute EventHandler onchecking;
-  attribute EventHandler onerror;
-  attribute EventHandler onnoupdate;
-  attribute EventHandler ondownloading;
-  attribute EventHandler onprogress;
-  attribute EventHandler onupdateready;
-  attribute EventHandler oncached;
-  attribute EventHandler onobsolete;
-};
-
-interface mixin NavigatorOnLine {
-  readonly attribute boolean onLine;
-};
-
-[Constructor(DOMString type, optional ErrorEventInit eventInitDict = {}), Exposed=(Window,Worker)]
-interface ErrorEvent : Event {
-  readonly attribute DOMString message;
-  readonly attribute USVString filename;
-  readonly attribute unsigned long lineno;
-  readonly attribute unsigned long colno;
-  readonly attribute any error;
-};
-
-dictionary ErrorEventInit : EventInit {
-  DOMString message = "";
-  USVString filename = "";
-  unsigned long lineno = 0;
-  unsigned long colno = 0;
-  any error = null;
-};
-
-[Constructor(DOMString type, PromiseRejectionEventInit eventInitDict), Exposed=(Window,Worker)]
-interface PromiseRejectionEvent : Event {
-  readonly attribute Promise<any> promise;
-  readonly attribute any reason;
-};
-
-dictionary PromiseRejectionEventInit : EventInit {
-  required Promise<any> promise;
-  any reason;
-};
-
-[TreatNonObjectAsNull]
-callback EventHandlerNonNull = any (Event event);
-typedef EventHandlerNonNull? EventHandler;
-
-[TreatNonObjectAsNull]
-callback OnErrorEventHandlerNonNull = any ((Event or DOMString) event, optional DOMString source, optional unsigned long lineno, optional unsigned long colno, optional any error);
-typedef OnErrorEventHandlerNonNull? OnErrorEventHandler;
-
-[TreatNonObjectAsNull]
-callback OnBeforeUnloadEventHandlerNonNull = DOMString? (Event event);
-typedef OnBeforeUnloadEventHandlerNonNull? OnBeforeUnloadEventHandler;
-
-interface mixin GlobalEventHandlers {
-  attribute EventHandler onabort;
-  attribute EventHandler onauxclick;
-  attribute EventHandler onblur;
-  attribute EventHandler oncancel;
-  attribute EventHandler oncanplay;
-  attribute EventHandler oncanplaythrough;
-  attribute EventHandler onchange;
-  attribute EventHandler onclick;
-  attribute EventHandler onclose;
-  attribute EventHandler oncontextmenu;
-  attribute EventHandler oncuechange;
-  attribute EventHandler ondblclick;
-  attribute EventHandler ondrag;
-  attribute EventHandler ondragend;
-  attribute EventHandler ondragenter;
-  attribute EventHandler ondragexit;
-  attribute EventHandler ondragleave;
-  attribute EventHandler ondragover;
-  attribute EventHandler ondragstart;
-  attribute EventHandler ondrop;
-  attribute EventHandler ondurationchange;
-  attribute EventHandler onemptied;
-  attribute EventHandler onended;
-  attribute OnErrorEventHandler onerror;
-  attribute EventHandler onfocus;
-  attribute EventHandler oninput;
-  attribute EventHandler oninvalid;
-  attribute EventHandler onkeydown;
-  attribute EventHandler onkeypress;
-  attribute EventHandler onkeyup;
-  attribute EventHandler onload;
-  attribute EventHandler onloadeddata;
-  attribute EventHandler onloadedmetadata;
-  attribute EventHandler onloadend;
-  attribute EventHandler onloadstart;
-  attribute EventHandler onmousedown;
-  [LenientThis] attribute EventHandler onmouseenter;
-  [LenientThis] attribute EventHandler onmouseleave;
-  attribute EventHandler onmousemove;
-  attribute EventHandler onmouseout;
-  attribute EventHandler onmouseover;
-  attribute EventHandler onmouseup;
-  attribute EventHandler onwheel;
-  attribute EventHandler onpause;
-  attribute EventHandler onplay;
-  attribute EventHandler onplaying;
-  attribute EventHandler onprogress;
-  attribute EventHandler onratechange;
-  attribute EventHandler onreset;
-  attribute EventHandler onresize;
-  attribute EventHandler onscroll;
-  attribute EventHandler onsecuritypolicyviolation;
-  attribute EventHandler onseeked;
-  attribute EventHandler onseeking;
-  attribute EventHandler onselect;
-  attribute EventHandler onstalled;
-  attribute EventHandler onsubmit;
-  attribute EventHandler onsuspend;
-  attribute EventHandler ontimeupdate;
-  attribute EventHandler ontoggle;
-  attribute EventHandler onvolumechange;
-  attribute EventHandler onwaiting;
-};
-
-interface mixin WindowEventHandlers {
-  attribute EventHandler onafterprint;
-  attribute EventHandler onbeforeprint;
-  attribute OnBeforeUnloadEventHandler onbeforeunload;
-  attribute EventHandler onhashchange;
-  attribute EventHandler onlanguagechange;
-  attribute EventHandler onmessage;
-  attribute EventHandler onmessageerror;
-  attribute EventHandler onoffline;
-  attribute EventHandler ononline;
-  attribute EventHandler onpagehide;
-  attribute EventHandler onpageshow;
-  attribute EventHandler onpopstate;
-  attribute EventHandler onrejectionhandled;
-  attribute EventHandler onstorage;
-  attribute EventHandler onunhandledrejection;
-  attribute EventHandler onunload;
-};
-
-interface mixin DocumentAndElementEventHandlers {
-  attribute EventHandler oncopy;
-  attribute EventHandler oncut;
-  attribute EventHandler onpaste;
-};
-
-typedef (DOMString or Function) TimerHandler;
-
-interface mixin WindowOrWorkerGlobalScope {
-  [Replaceable] readonly attribute USVString origin;
-
-  // base64 utility methods
-  DOMString btoa(DOMString data);
-  ByteString atob(DOMString data);
-
-  // timers
-  long setTimeout(TimerHandler handler, optional long timeout = 0, any... arguments);
-  void clearTimeout(optional long handle = 0);
-  long setInterval(TimerHandler handler, optional long timeout = 0, any... arguments);
-  void clearInterval(optional long handle = 0);
-
-  // ImageBitmap
-  Promise<ImageBitmap> createImageBitmap(ImageBitmapSource image, optional ImageBitmapOptions options = {});
-  Promise<ImageBitmap> createImageBitmap(ImageBitmapSource image, long sx, long sy, long sw, long sh, optional ImageBitmapOptions options = {});
-};
-Window includes WindowOrWorkerGlobalScope;
-WorkerGlobalScope includes WindowOrWorkerGlobalScope;
-
-[Exposed=Window]
-interface Navigator {
-  // objects implementing this interface also implement the interfaces given below
-};
-Navigator includes NavigatorID;
-Navigator includes NavigatorLanguage;
-Navigator includes NavigatorOnLine;
-Navigator includes NavigatorContentUtils;
-Navigator includes NavigatorCookies;
-Navigator includes NavigatorPlugins;
-Navigator includes NavigatorConcurrentHardware;
-
-interface mixin NavigatorID {
-  readonly attribute DOMString appCodeName; // constant "Mozilla"
-  readonly attribute DOMString appName; // constant "Netscape"
-  readonly attribute DOMString appVersion;
-  readonly attribute DOMString platform;
-  readonly attribute DOMString product; // constant "Gecko"
-  [Exposed=Window] readonly attribute DOMString productSub;
-  readonly attribute DOMString userAgent;
-  [Exposed=Window] readonly attribute DOMString vendor;
-  [Exposed=Window] readonly attribute DOMString vendorSub; // constant ""
-};
-
-partial interface NavigatorID {
-  [Exposed=Window] boolean taintEnabled(); // constant false
-  [Exposed=Window] readonly attribute DOMString oscpu;
-};
-
-interface mixin NavigatorLanguage {
-  readonly attribute DOMString language;
-  readonly attribute FrozenArray<DOMString> languages;
-};
-
-interface mixin NavigatorContentUtils {
-  void registerProtocolHandler(DOMString scheme, USVString url, DOMString title);
-  void unregisterProtocolHandler(DOMString scheme, USVString url);
-};
-
-interface mixin NavigatorCookies {
-  readonly attribute boolean cookieEnabled;
-};
-
-interface mixin NavigatorPlugins {
-  [SameObject] readonly attribute PluginArray plugins;
-  [SameObject] readonly attribute MimeTypeArray mimeTypes;
-  boolean javaEnabled();
-};
-
-[Exposed=Window,
- LegacyUnenumerableNamedProperties]
-interface PluginArray {
-  void refresh(optional boolean reload = false);
-  readonly attribute unsigned long length;
-  getter Plugin? item(unsigned long index);
-  getter Plugin? namedItem(DOMString name);
-};
-
-[Exposed=Window,
- LegacyUnenumerableNamedProperties]
-interface MimeTypeArray {
-  readonly attribute unsigned long length;
-  getter MimeType? item(unsigned long index);
-  getter MimeType? namedItem(DOMString name);
-};
-
-[Exposed=Window,
- LegacyUnenumerableNamedProperties]
-interface Plugin {
-  readonly attribute DOMString name;
-  readonly attribute DOMString description;
-  readonly attribute DOMString filename;
-  readonly attribute unsigned long length;
-  getter MimeType? item(unsigned long index);
-  getter MimeType? namedItem(DOMString name);
-};
-
-[Exposed=Window]
-interface MimeType {
-  readonly attribute DOMString type;
-  readonly attribute DOMString description;
-  readonly attribute DOMString suffixes; // comma-separated
-  readonly attribute Plugin enabledPlugin;
-};
-
-[Exposed=(Window,Worker), Serializable, Transferable]
-interface ImageBitmap {
-  readonly attribute unsigned long width;
-  readonly attribute unsigned long height;
-  void close();
-};
-
-typedef (CanvasImageSource or
-         Blob or
-         ImageData) ImageBitmapSource;
-
-enum ImageOrientation { "none", "flipY" };
-enum PremultiplyAlpha { "none", "premultiply", "default" };
-enum ColorSpaceConversion { "none", "default" };
-enum ResizeQuality { "pixelated", "low", "medium", "high" };
-
-dictionary ImageBitmapOptions {
-  ImageOrientation imageOrientation = "none";
-  PremultiplyAlpha premultiplyAlpha = "default";
-  ColorSpaceConversion colorSpaceConversion = "default";
-  [EnforceRange] unsigned long resizeWidth;
-  [EnforceRange] unsigned long resizeHeight;
-  ResizeQuality resizeQuality = "low";
-};
-
-[Constructor(DOMString type, optional MessageEventInit eventInitDict = {}), Exposed=(Window,Worker,AudioWorklet)]
-interface MessageEvent : Event {
-  readonly attribute any data;
-  readonly attribute USVString origin;
-  readonly attribute DOMString lastEventId;
-  readonly attribute MessageEventSource? source;
-  readonly attribute FrozenArray<MessagePort> ports;
-
-  void initMessageEvent(DOMString type, optional boolean bubbles = false, optional boolean cancelable = false, optional any data = null, optional USVString origin = "", optional DOMString lastEventId = "", optional MessageEventSource? source = null, optional sequence<MessagePort> ports = []);
-};
-
-dictionary MessageEventInit : EventInit {
-  any data = null;
-  USVString origin = "";
-  DOMString lastEventId = "";
-  MessageEventSource? source = null;
-  sequence<MessagePort> ports = [];
-};
-
-typedef (WindowProxy or MessagePort or ServiceWorker) MessageEventSource;
-
-[Constructor(USVString url, optional EventSourceInit eventSourceInitDict = {}), Exposed=(Window,Worker)]
-interface EventSource : EventTarget {
-  readonly attribute USVString url;
-  readonly attribute boolean withCredentials;
-
-  // ready state
-  const unsigned short CONNECTING = 0;
-  const unsigned short OPEN = 1;
-  const unsigned short CLOSED = 2;
-  readonly attribute unsigned short readyState;
-
-  // networking
-  attribute EventHandler onopen;
-  attribute EventHandler onmessage;
-  attribute EventHandler onerror;
-  void close();
-};
-
-dictionary EventSourceInit {
-  boolean withCredentials = false;
-};
-
-enum BinaryType { "blob", "arraybuffer" };
-[Constructor(USVString url, optional (DOMString or sequence<DOMString>) protocols = []), Exposed=(Window,Worker)]
-interface WebSocket : EventTarget {
-  readonly attribute USVString url;
-
-  // ready state
-  const unsigned short CONNECTING = 0;
-  const unsigned short OPEN = 1;
-  const unsigned short CLOSING = 2;
-  const unsigned short CLOSED = 3;
-  readonly attribute unsigned short readyState;
-  readonly attribute unsigned long long bufferedAmount;
-
-  // networking
-  attribute EventHandler onopen;
-  attribute EventHandler onerror;
-  attribute EventHandler onclose;
-  readonly attribute DOMString extensions;
-  readonly attribute DOMString protocol;
-  void close(optional [Clamp] unsigned short code, optional USVString reason);
-
-  // messaging
-  attribute EventHandler onmessage;
-  attribute BinaryType binaryType;
-  void send(USVString data);
-  void send(Blob data);
-  void send(ArrayBuffer data);
-  void send(ArrayBufferView data);
-};
-
-[Constructor(DOMString type, optional CloseEventInit eventInitDict = {}), Exposed=(Window,Worker)]
-interface CloseEvent : Event {
-  readonly attribute boolean wasClean;
-  readonly attribute unsigned short code;
-  readonly attribute USVString reason;
-};
-
-dictionary CloseEventInit : EventInit {
-  boolean wasClean = false;
-  unsigned short code = 0;
-  USVString reason = "";
-};
-
-[Constructor, Exposed=(Window,Worker)]
-interface MessageChannel {
-  readonly attribute MessagePort port1;
-  readonly attribute MessagePort port2;
-};
-
-[Exposed=(Window,Worker,AudioWorklet), Transferable]
-interface MessagePort : EventTarget {
-  void postMessage(any message, optional sequence<object> transfer = []);
-  void start();
-  void close();
-
-  // event handlers
-  attribute EventHandler onmessage;
-  attribute EventHandler onmessageerror;
-};
-
-[Constructor(DOMString name), Exposed=(Window,Worker)]
-interface BroadcastChannel : EventTarget {
-  readonly attribute DOMString name;
-  void postMessage(any message);
-  void close();
-  attribute EventHandler onmessage;
-  attribute EventHandler onmessageerror;
-};
-
-[Exposed=Worker]
-interface WorkerGlobalScope : EventTarget {
-  readonly attribute WorkerGlobalScope self;
-  readonly attribute WorkerLocation location;
-  readonly attribute WorkerNavigator navigator;
-  void importScripts(USVString... urls);
-
-  attribute OnErrorEventHandler onerror;
-  attribute EventHandler onlanguagechange;
-  attribute EventHandler onoffline;
-  attribute EventHandler ononline;
-  attribute EventHandler onrejectionhandled;
-  attribute EventHandler onunhandledrejection;
-};
-
-[Global=(Worker,DedicatedWorker),Exposed=DedicatedWorker]
-interface DedicatedWorkerGlobalScope : WorkerGlobalScope {
-  [Replaceable] readonly attribute DOMString name;
-
-  void postMessage(any message, optional sequence<object> transfer = []);
-
-  void close();
-
-  attribute EventHandler onmessage;
-  attribute EventHandler onmessageerror;
-};
-
-[Global=(Worker,SharedWorker),Exposed=SharedWorker]
-interface SharedWorkerGlobalScope : WorkerGlobalScope {
-  [Replaceable] readonly attribute DOMString name;
-
-  void close();
-
-  attribute EventHandler onconnect;
-};
-
-interface mixin AbstractWorker {
-  attribute EventHandler onerror;
-};
-
-[Constructor(USVString scriptURL, optional WorkerOptions options = {}), Exposed=(Window,Worker)]
-interface Worker : EventTarget {
-  void terminate();
-
-  void postMessage(any message, optional sequence<object> transfer = []);
-  attribute EventHandler onmessage;
-  attribute EventHandler onmessageerror;
-};
-
-dictionary WorkerOptions {
-  WorkerType type = "classic";
-  RequestCredentials credentials = "omit"; // credentials is only used if type is "module"
-  DOMString name = "";
-};
-
-enum WorkerType { "classic", "module" };
-
-Worker includes AbstractWorker;
-
-[Constructor(USVString scriptURL, optional (DOMString or WorkerOptions) options = {}),
- Exposed=(Window,Worker)]
-interface SharedWorker : EventTarget {
-  readonly attribute MessagePort port;
-};
-SharedWorker includes AbstractWorker;
-
-interface mixin NavigatorConcurrentHardware {
-  readonly attribute unsigned long long hardwareConcurrency;
-};
-
-[Exposed=Worker]
-interface WorkerNavigator {};
-WorkerNavigator includes NavigatorID;
-WorkerNavigator includes NavigatorLanguage;
-WorkerNavigator includes NavigatorOnLine;
-WorkerNavigator includes NavigatorConcurrentHardware;
-
-[Exposed=Worker]
-interface WorkerLocation {
-  stringifier readonly attribute USVString href;
-  readonly attribute USVString origin;
-  readonly attribute USVString protocol;
-  readonly attribute USVString host;
-  readonly attribute USVString hostname;
-  readonly attribute USVString port;
-  readonly attribute USVString pathname;
-  readonly attribute USVString search;
-  readonly attribute USVString hash;
-};
-
-[Exposed=Window]
-interface Storage {
-  readonly attribute unsigned long length;
-  DOMString? key(unsigned long index);
-  getter DOMString? getItem(DOMString key);
-  setter void setItem(DOMString key, DOMString value);
-  deleter void removeItem(DOMString key);
-  void clear();
-};
-
-interface mixin WindowSessionStorage {
-  readonly attribute Storage sessionStorage;
-};
-Window includes WindowSessionStorage;
-
-interface mixin WindowLocalStorage {
-  readonly attribute Storage localStorage;
-};
-Window includes WindowLocalStorage;
-
-[Exposed=Window,
- Constructor(DOMString type, optional StorageEventInit eventInitDict = {})]
-interface StorageEvent : Event {
-  readonly attribute DOMString? key;
-  readonly attribute DOMString? oldValue;
-  readonly attribute DOMString? newValue;
-  readonly attribute USVString url;
-  readonly attribute Storage? storageArea;
-};
-
-dictionary StorageEventInit : EventInit {
-  DOMString? key = null;
-  DOMString? oldValue = null;
-  DOMString? newValue = null;
-  USVString url = "";
-  Storage? storageArea = null;
-};
-
-[Exposed=Window,
- HTMLConstructor]
-interface HTMLMarqueeElement : HTMLElement {
-  [CEReactions] attribute DOMString behavior;
-  [CEReactions] attribute DOMString bgColor;
-  [CEReactions] attribute DOMString direction;
-  [CEReactions] attribute DOMString height;
-  [CEReactions] attribute unsigned long hspace;
-  [CEReactions] attribute long loop;
-  [CEReactions] attribute unsigned long scrollAmount;
-  [CEReactions] attribute unsigned long scrollDelay;
-  [CEReactions] attribute boolean trueSpeed;
-  [CEReactions] attribute unsigned long vspace;
-  [CEReactions] attribute DOMString width;
-
-  attribute EventHandler onbounce;
-  attribute EventHandler onfinish;
-  attribute EventHandler onstart;
-
-  void start();
-  void stop();
-};
-
-[Exposed=Window,
- HTMLConstructor]
-interface HTMLFrameSetElement : HTMLElement {
-  [CEReactions] attribute DOMString cols;
-  [CEReactions] attribute DOMString rows;
-};
-HTMLFrameSetElement includes WindowEventHandlers;
-
-[Exposed=Window,
- HTMLConstructor]
-interface HTMLFrameElement : HTMLElement {
-  [CEReactions] attribute DOMString name;
-  [CEReactions] attribute DOMString scrolling;
-  [CEReactions] attribute USVString src;
-  [CEReactions] attribute DOMString frameBorder;
-  [CEReactions] attribute USVString longDesc;
-  [CEReactions] attribute boolean noResize;
-  readonly attribute Document? contentDocument;
-  readonly attribute WindowProxy? contentWindow;
-
-  [CEReactions] attribute [TreatNullAs=EmptyString] DOMString marginHeight;
-  [CEReactions] attribute [TreatNullAs=EmptyString] DOMString marginWidth;
-};
-
-partial interface HTMLAnchorElement {
-  [CEReactions] attribute DOMString coords;
-  [CEReactions] attribute DOMString charset;
-  [CEReactions] attribute DOMString name;
-  [CEReactions] attribute DOMString rev;
-  [CEReactions] attribute DOMString shape;
-};
-
-partial interface HTMLAreaElement {
-  [CEReactions] attribute boolean noHref;
-};
-
-partial interface HTMLBodyElement {
-  [CEReactions] attribute [TreatNullAs=EmptyString] DOMString text;
-  [CEReactions] attribute [TreatNullAs=EmptyString] DOMString link;
-  [CEReactions] attribute [TreatNullAs=EmptyString] DOMString vLink;
-  [CEReactions] attribute [TreatNullAs=EmptyString] DOMString aLink;
-  [CEReactions] attribute [TreatNullAs=EmptyString] DOMString bgColor;
-  [CEReactions] attribute DOMString background;
-};
-
-partial interface HTMLBRElement {
-  [CEReactions] attribute DOMString clear;
-};
-
-partial interface HTMLTableCaptionElement {
-  [CEReactions] attribute DOMString align;
-};
-
-partial interface HTMLTableColElement {
-  [CEReactions] attribute DOMString align;
-  [CEReactions] attribute DOMString ch;
-  [CEReactions] attribute DOMString chOff;
-  [CEReactions] attribute DOMString vAlign;
-  [CEReactions] attribute DOMString width;
-};
-
-[Exposed=Window,
- HTMLConstructor]
-interface HTMLDirectoryElement : HTMLElement {
-  [CEReactions] attribute boolean compact;
-};
-
-partial interface HTMLDivElement {
-  [CEReactions] attribute DOMString align;
-};
-
-partial interface HTMLDListElement {
-  [CEReactions] attribute boolean compact;
-};
-
-partial interface HTMLEmbedElement {
-  [CEReactions] attribute DOMString align;
-  [CEReactions] attribute DOMString name;
-};
-
-[Exposed=Window,
- HTMLConstructor]
-interface HTMLFontElement : HTMLElement {
-  [CEReactions] attribute [TreatNullAs=EmptyString] DOMString color;
-  [CEReactions] attribute DOMString face;
-  [CEReactions] attribute DOMString size;
-};
-
-partial interface HTMLHeadingElement {
-  [CEReactions] attribute DOMString align;
-};
-
-partial interface HTMLHRElement {
-  [CEReactions] attribute DOMString align;
-  [CEReactions] attribute DOMString color;
-  [CEReactions] attribute boolean noShade;
-  [CEReactions] attribute DOMString size;
-  [CEReactions] attribute DOMString width;
-};
-
-partial interface HTMLHtmlElement {
-  [CEReactions] attribute DOMString version;
-};
-
-partial interface HTMLIFrameElement {
-  [CEReactions] attribute DOMString align;
-  [CEReactions] attribute DOMString scrolling;
-  [CEReactions] attribute DOMString frameBorder;
-  [CEReactions] attribute USVString longDesc;
-
-  [CEReactions] attribute [TreatNullAs=EmptyString] DOMString marginHeight;
-  [CEReactions] attribute [TreatNullAs=EmptyString] DOMString marginWidth;
-};
-
-partial interface HTMLImageElement {
-  [CEReactions] attribute DOMString name;
-  [CEReactions] attribute USVString lowsrc;
-  [CEReactions] attribute DOMString align;
-  [CEReactions] attribute unsigned long hspace;
-  [CEReactions] attribute unsigned long vspace;
-  [CEReactions] attribute USVString longDesc;
-
-  [CEReactions] attribute [TreatNullAs=EmptyString] DOMString border;
-};
-
-partial interface HTMLInputElement {
-  [CEReactions] attribute DOMString align;
-  [CEReactions] attribute DOMString useMap;
-};
-
-partial interface HTMLLegendElement {
-  [CEReactions] attribute DOMString align;
-};
-
-partial interface HTMLLIElement {
-  [CEReactions] attribute DOMString type;
-};
-
-partial interface HTMLLinkElement {
-  [CEReactions] attribute DOMString charset;
-  [CEReactions] attribute DOMString rev;
-  [CEReactions] attribute DOMString target;
-};
-
-partial interface HTMLMenuElement {
-  [CEReactions] attribute boolean compact;
-};
-
-partial interface HTMLMetaElement {
-  [CEReactions] attribute DOMString scheme;
-};
-
-partial interface HTMLObjectElement {
-  [CEReactions] attribute DOMString align;
-  [CEReactions] attribute DOMString archive;
-  [CEReactions] attribute DOMString code;
-  [CEReactions] attribute boolean declare;
-  [CEReactions] attribute unsigned long hspace;
-  [CEReactions] attribute DOMString standby;
-  [CEReactions] attribute unsigned long vspace;
-  [CEReactions] attribute DOMString codeBase;
-  [CEReactions] attribute DOMString codeType;
-
-  [CEReactions] attribute [TreatNullAs=EmptyString] DOMString border;
-};
-
-partial interface HTMLOListElement {
-  [CEReactions] attribute boolean compact;
-};
-
-partial interface HTMLParagraphElement {
-  [CEReactions] attribute DOMString align;
-};
-
-partial interface HTMLParamElement {
-  [CEReactions] attribute DOMString type;
-  [CEReactions] attribute DOMString valueType;
-};
-
-partial interface HTMLPreElement {
-  [CEReactions] attribute long width;
-};
-
-partial interface HTMLStyleElement {
-  [CEReactions] attribute DOMString type;
-};
-
-partial interface HTMLScriptElement {
-  [CEReactions] attribute DOMString charset;
-  [CEReactions] attribute DOMString event;
-  [CEReactions] attribute DOMString htmlFor;
-};
-
-partial interface HTMLTableElement {
-  [CEReactions] attribute DOMString align;
-  [CEReactions] attribute DOMString border;
-  [CEReactions] attribute DOMString frame;
-  [CEReactions] attribute DOMString rules;
-  [CEReactions] attribute DOMString summary;
-  [CEReactions] attribute DOMString width;
-
-  [CEReactions] attribute [TreatNullAs=EmptyString] DOMString bgColor;
-  [CEReactions] attribute [TreatNullAs=EmptyString] DOMString cellPadding;
-  [CEReactions] attribute [TreatNullAs=EmptyString] DOMString cellSpacing;
-};
-
-partial interface HTMLTableSectionElement {
-  [CEReactions] attribute DOMString align;
-  [CEReactions] attribute DOMString ch;
-  [CEReactions] attribute DOMString chOff;
-  [CEReactions] attribute DOMString vAlign;
-};
-
-partial interface HTMLTableCellElement {
-  [CEReactions] attribute DOMString align;
-  [CEReactions] attribute DOMString axis;
-  [CEReactions] attribute DOMString height;
-  [CEReactions] attribute DOMString width;
-
-  [CEReactions] attribute DOMString ch;
-  [CEReactions] attribute DOMString chOff;
-  [CEReactions] attribute boolean noWrap;
-  [CEReactions] attribute DOMString vAlign;
-
-  [CEReactions] attribute [TreatNullAs=EmptyString] DOMString bgColor;
-};
-
-partial interface HTMLTableRowElement {
-  [CEReactions] attribute DOMString align;
-  [CEReactions] attribute DOMString ch;
-  [CEReactions] attribute DOMString chOff;
-  [CEReactions] attribute DOMString vAlign;
-
-  [CEReactions] attribute [TreatNullAs=EmptyString] DOMString bgColor;
-};
-
-partial interface HTMLUListElement {
-  [CEReactions] attribute boolean compact;
-  [CEReactions] attribute DOMString type;
-};
-
-partial interface Document {
-  [CEReactions] attribute [TreatNullAs=EmptyString] DOMString fgColor;
-  [CEReactions] attribute [TreatNullAs=EmptyString] DOMString linkColor;
-  [CEReactions] attribute [TreatNullAs=EmptyString] DOMString vlinkColor;
-  [CEReactions] attribute [TreatNullAs=EmptyString] DOMString alinkColor;
-  [CEReactions] attribute [TreatNullAs=EmptyString] DOMString bgColor;
-
-  [SameObject] readonly attribute HTMLCollection anchors;
-  [SameObject] readonly attribute HTMLCollection applets;
-
-  void clear();
-  void captureEvents();
-  void releaseEvents();
-
-  [SameObject] readonly attribute HTMLAllCollection all;
-};
-
-partial interface Window {
-  void captureEvents();
-  void releaseEvents();
-
-  [Replaceable, SameObject] readonly attribute External external;
-};
-
-[Exposed=Window,
- NoInterfaceObject]
-interface External {
-  void AddSearchProvider();
-  void IsSearchProviderInstalled();
-};
diff --git a/third_party/rust/weedle/tests/defs/interface-constructor.webidl b/third_party/rust/weedle/tests/defs/interface-constructor.webidl
deleted file mode 100644
index 93cb28a4af..0000000000
--- a/third_party/rust/weedle/tests/defs/interface-constructor.webidl
+++ /dev/null
@@ -1,4 +0,0 @@
-interface InterfaceWithConstructor {
-  [Throws]
-  constructor(long a);
-};
diff --git a/third_party/rust/weedle/tests/defs/mediacapture-streams.webidl b/third_party/rust/weedle/tests/defs/mediacapture-streams.webidl
deleted file mode 100644
index 5780cfb34e..0000000000
--- a/third_party/rust/weedle/tests/defs/mediacapture-streams.webidl
+++ /dev/null
@@ -1,246 +0,0 @@
-[Exposed=Window,
- Constructor,
- Constructor(MediaStream stream),
- Constructor(sequence<MediaStreamTrack> tracks)]
-interface MediaStream : EventTarget {
-    readonly        attribute DOMString id;
-    sequence<MediaStreamTrack> getAudioTracks();
-    sequence<MediaStreamTrack> getVideoTracks();
-    sequence<MediaStreamTrack> getTracks();
-    MediaStreamTrack? getTrackById(DOMString trackId);
-    void addTrack(MediaStreamTrack track);
-    void removeTrack(MediaStreamTrack track);
-    MediaStream clone();
-    readonly        attribute boolean active;
-                    attribute EventHandler onaddtrack;
-                    attribute EventHandler onremovetrack;
-};
-
-[Exposed=Window]
-interface MediaStreamTrack : EventTarget {
-    readonly        attribute DOMString kind;
-    readonly        attribute DOMString id;
-    readonly        attribute DOMString label;
-                    attribute boolean enabled;
-    readonly        attribute boolean muted;
-                    attribute EventHandler onmute;
-                    attribute EventHandler onunmute;
-    readonly        attribute MediaStreamTrackState readyState;
-                    attribute EventHandler onended;
-    MediaStreamTrack clone();
-    void stop();
-    MediaTrackCapabilities getCapabilities();
-    MediaTrackConstraints getConstraints();
-    MediaTrackSettings getSettings();
-    Promise<void> applyConstraints(optional MediaTrackConstraints constraints = {});
-};
-
-enum MediaStreamTrackState {
-    "live",
-    "ended"
-};
-
-dictionary MediaTrackSupportedConstraints {
-             boolean width = true;
-             boolean height = true;
-             boolean aspectRatio = true;
-             boolean frameRate = true;
-             boolean facingMode = true;
-             boolean resizeMode = true;
-             boolean volume = true;
-             boolean sampleRate = true;
-             boolean sampleSize = true;
-             boolean echoCancellation = true;
-             boolean autoGainControl = true;
-             boolean noiseSuppression = true;
-             boolean latency = true;
-             boolean channelCount = true;
-             boolean deviceId = true;
-             boolean groupId = true;
-};
-
-dictionary MediaTrackCapabilities {
-             ULongRange width;
-             ULongRange height;
-             DoubleRange aspectRatio;
-             DoubleRange frameRate;
-             sequence<DOMString> facingMode;
-             sequence<DOMString> resizeMode;
-             DoubleRange volume;
-             ULongRange sampleRate;
-             ULongRange sampleSize;
-             sequence<boolean> echoCancellation;
-             sequence<boolean> autoGainControl;
-             sequence<boolean> noiseSuppression;
-             DoubleRange latency;
-             ULongRange channelCount;
-             DOMString deviceId;
-             DOMString groupId;
-};
-
-dictionary MediaTrackConstraints : MediaTrackConstraintSet {
-             sequence<MediaTrackConstraintSet> advanced;
-};
-
-dictionary MediaTrackConstraintSet {
-             ConstrainULong width;
-             ConstrainULong height;
-             ConstrainDouble aspectRatio;
-             ConstrainDouble frameRate;
-             ConstrainDOMString facingMode;
-             ConstrainDOMString resizeMode;
-             ConstrainDouble volume;
-             ConstrainULong sampleRate;
-             ConstrainULong sampleSize;
-             ConstrainBoolean echoCancellation;
-             ConstrainBoolean autoGainControl;
-             ConstrainBoolean noiseSuppression;
-             ConstrainDouble latency;
-             ConstrainULong channelCount;
-             ConstrainDOMString deviceId;
-             ConstrainDOMString groupId;
-};
-
-dictionary MediaTrackSettings {
-             long width;
-             long height;
-             double aspectRatio;
-             double frameRate;
-             DOMString facingMode;
-             DOMString resizeMode;
-             double volume;
-             long sampleRate;
-             long sampleSize;
-             boolean echoCancellation;
-             boolean autoGainControl;
-             boolean noiseSuppression;
-             double latency;
-             long channelCount;
-             DOMString deviceId;
-             DOMString groupId;
-};
-
-enum VideoFacingModeEnum {
-    "user",
-    "environment",
-    "left",
-    "right"
-};
-
-enum VideoResizeModeEnum {
-    "none",
-    "crop-and-scale"
-};
-
-[Exposed=Window,
- Constructor(DOMString type, MediaStreamTrackEventInit eventInitDict)]
-interface MediaStreamTrackEvent : Event {
-    [SameObject]
-    readonly        attribute MediaStreamTrack track;
-};
-
-dictionary MediaStreamTrackEventInit : EventInit {
-    required MediaStreamTrack track;
-};
-
-partial interface Navigator {
-    [SameObject, SecureContext]
-    readonly        attribute MediaDevices mediaDevices;
-};
-
-[Exposed=Window, SecureContext]
-interface MediaDevices : EventTarget {
-                    attribute EventHandler ondevicechange;
-    Promise<sequence<MediaDeviceInfo>> enumerateDevices();
-};
-
-[Exposed=Window, SecureContext]
-interface MediaDeviceInfo {
-    readonly        attribute DOMString deviceId;
-    readonly        attribute MediaDeviceKind kind;
-    readonly        attribute DOMString label;
-    readonly        attribute DOMString groupId;
-    [Default] object toJSON();
-};
-
-enum MediaDeviceKind {
-    "audioinput",
-    "audiooutput",
-    "videoinput"
-};
-
-[Exposed=Window] interface InputDeviceInfo : MediaDeviceInfo {
-    MediaTrackCapabilities getCapabilities();
-};
-
-partial interface Navigator {
-    [SecureContext]
-    void getUserMedia(MediaStreamConstraints constraints, NavigatorUserMediaSuccessCallback successCallback, NavigatorUserMediaErrorCallback errorCallback);
-};
-
-partial interface MediaDevices {
-    MediaTrackSupportedConstraints getSupportedConstraints();
-    Promise<MediaStream> getUserMedia(optional MediaStreamConstraints constraints = {});
-};
-
-dictionary MediaStreamConstraints {
-             (boolean or MediaTrackConstraints) video = false;
-             (boolean or MediaTrackConstraints) audio = false;
-};
-
-callback NavigatorUserMediaSuccessCallback = void (MediaStream stream);
-
-callback NavigatorUserMediaErrorCallback = void (MediaStreamError error);
-
-typedef object MediaStreamError;
-
-dictionary DoubleRange {
-             double max;
-             double min;
-};
-
-dictionary ConstrainDoubleRange : DoubleRange {
-             double exact;
-             double ideal;
-};
-
-dictionary ULongRange {
-             [Clamp] unsigned long max;
-             [Clamp] unsigned long min;
-};
-
-dictionary ConstrainULongRange : ULongRange {
-             [Clamp] unsigned long exact;
-             [Clamp] unsigned long ideal;
-};
-
-dictionary ConstrainBooleanParameters {
-             boolean exact;
-             boolean ideal;
-};
-
-dictionary ConstrainDOMStringParameters {
-             (DOMString or sequence<DOMString>) exact;
-             (DOMString or sequence<DOMString>) ideal;
-};
-
-typedef ([Clamp] unsigned long or ConstrainULongRange) ConstrainULong;
-
-typedef (double or ConstrainDoubleRange) ConstrainDouble;
-
-typedef (boolean or ConstrainBooleanParameters) ConstrainBoolean;
-
-typedef (DOMString or sequence<DOMString> or ConstrainDOMStringParameters) ConstrainDOMString;
-
-dictionary Capabilities {
-};
-
-dictionary Settings {
-};
-
-dictionary ConstraintSet {
-};
-
-dictionary Constraints : ConstraintSet {
-             sequence<ConstraintSet> advanced;
-};
diff --git a/third_party/rust/weedle/tests/webidl.rs b/third_party/rust/weedle/tests/webidl.rs
deleted file mode 100644
index 7aaf815218..0000000000
--- a/third_party/rust/weedle/tests/webidl.rs
+++ /dev/null
@@ -1,99 +0,0 @@
-extern crate weedle;
-
-use std::fs;
-use std::io::Read;
-
-use weedle::*;
-
-fn read_file(path: &str) -> String {
-    let mut file = fs::File::open(path).unwrap();
-    let mut file_content = String::new();
-    file.read_to_string(&mut file_content).unwrap();
-    file_content
-}
-
-#[test]
-pub fn should_parse_dom_webidl() {
-    let content = read_file("./tests/defs/dom.webidl");
-    let parsed = weedle::parse(&content).unwrap();
-
-    assert_eq!(parsed.len(), 62);
-}
-
-#[test]
-fn should_parse_html_webidl() {
-    let content = read_file("./tests/defs/html.webidl");
-    let parsed = weedle::parse(&content).unwrap();
-
-    assert_eq!(parsed.len(), 325);
-}
-
-#[test]
-fn should_parse_mediacapture_streams_webidl() {
-    let content = read_file("./tests/defs/mediacapture-streams.webidl");
-    let parsed = weedle::parse(&content).unwrap();
-
-    assert_eq!(parsed.len(), 37);
-}
-
-#[test]
-fn interface_constructor() {
-    let content = read_file("./tests/defs/interface-constructor.webidl");
-    let mut parsed = weedle::parse(&content).unwrap();
-
-    assert_eq!(parsed.len(), 1);
-
-    let definition = parsed.pop().unwrap();
-
-    match definition {
-        Definition::Interface(mut interface) => {
-            assert!(interface.attributes.is_none());
-            assert_eq!(interface.interface, term!(interface));
-            assert_eq!(interface.identifier.0, "InterfaceWithConstructor");
-            assert_eq!(interface.inheritance, None);
-
-            assert_eq!(interface.members.body.len(), 1);
-
-            let body = interface.members.body.pop().unwrap();
-
-            match body {
-                interface::InterfaceMember::Constructor(constructor) => {
-                    let mut attributes = constructor.attributes.unwrap().body.list;
-                    assert_eq!(attributes.len(), 1);
-                    let attribute = attributes.pop().unwrap();
-
-                    match attribute {
-                        attribute::ExtendedAttribute::NoArgs(attribute) => {
-                            assert_eq!((attribute.0).0, "Throws");
-                        }
-                        _ => unreachable!(),
-                    }
-
-                    let mut args = constructor.args.body.list;
-                    assert_eq!(args.len(), 1);
-                    let arg = args.pop().unwrap();
-
-                    match arg {
-                        argument::Argument::Single(arg) => {
-                            assert!(arg.attributes.is_none());
-                            assert!(arg.optional.is_none());
-                            assert!(arg.type_.attributes.is_none());
-
-                            match arg.type_.type_ {
-                                types::Type::Single(types::SingleType::NonAny(
-                                    types::NonAnyType::Integer(_),
-                                )) => {}
-                                _ => unreachable!(),
-                            }
-                        }
-                        _ => unreachable!(),
-                    };
-
-                    assert_eq!(constructor.constructor, term::Constructor);
-                }
-                _ => unreachable!(),
-            }
-        }
-        _ => unreachable!(),
-    }
-}
diff --git a/toolkit/components/aboutmemory/content/aboutMemory.js b/toolkit/components/aboutmemory/content/aboutMemory.js
index 66a9cc7ccb..403e47d5a7 100644
--- a/toolkit/components/aboutmemory/content/aboutMemory.js
+++ b/toolkit/components/aboutmemory/content/aboutMemory.js
@@ -145,7 +145,7 @@ function stringMatchesFilter(aString, aFilter) {
 
 // ---------------------------------------------------------------------------
 
-function onUnload() {}
+window.onunload = function() {};
 
 // ---------------------------------------------------------------------------
 
@@ -302,7 +302,7 @@ function appendHiddenFileInput(aP, aId, aChangeListener) {
   return input;
 }
 
-function onLoad() {
+window.onload = function() {
   // Generate the header.
 
   let header = appendElement(document.body, "div", "ancillary");
@@ -492,7 +492,7 @@ function onLoad() {
       }
     }
   }
-}
+};
 
 // ---------------------------------------------------------------------------
 
diff --git a/toolkit/components/aboutmemory/content/aboutMemory.xhtml b/toolkit/components/aboutmemory/content/aboutMemory.xhtml
index 9d8626d595..fb85a7baf1 100644
--- a/toolkit/components/aboutmemory/content/aboutMemory.xhtml
+++ b/toolkit/components/aboutmemory/content/aboutMemory.xhtml
@@ -6,11 +6,12 @@
 
 <html xmlns="http://www.w3.org/1999/xhtml">
   <head>
+    <meta http-equiv="Content-Security-Policy" content="default-src chrome:" />
     <meta name="viewport" content="width=device-width"/>
     <title>Memory Analyzer</title>
     <link rel="stylesheet" href="chrome://global/skin/aboutMemory.css" type="text/css"/>
     <script src="chrome://global/content/aboutMemory.js"/>
   </head>
 
-  <body onload="onLoad()" onunload="onUnload()"></body>
+  <body></body>
 </html>
diff --git a/toolkit/components/aboutmemory/tests/test_memoryReporters.xul b/toolkit/components/aboutmemory/tests/test_memoryReporters.xul
index 840b61168e..a665df76bb 100644
--- a/toolkit/components/aboutmemory/tests/test_memoryReporters.xul
+++ b/toolkit/components/aboutmemory/tests/test_memoryReporters.xul
@@ -60,16 +60,18 @@
   let bigStringPrefix = bigString.substring(0, 100);
 
   // Generate many copies of two distinctive short strings, "!)(*&" and
-  // "@)(*&".  We'll check that these strings are reported in at least
-  // one of the memory reporters.
+  // "@)(*&". We'll check that these strings are reported in at least one of
+  // the memory reporters. We will create these strings in the tenured heap to
+  // avoid nursery string deduplication.
   let shortStrings = [];
+  let newString = Cu.getJSTestingFunctions().newString;
   for (let i = 0; i < 10000; i++) {
     let str = (Math.random() > 0.5 ? "!" : "@") + ")(*&";
-    shortStrings.push(str);
+    shortStrings.push(newString(str, {tenured: true}));
   }
 
   // Strings in the nursery are not reported, so make sure the above test
-  // strings are tenured.
+  // strings are tenured (not all are created tenured).
   Cu.forceGC();
 
   let mySandbox = Cu.Sandbox(document.nodePrincipal,
diff --git a/toolkit/components/aboutperformance/content/aboutPerformance.css b/toolkit/components/aboutperformance/content/aboutPerformance.css
new file mode 100644
index 0000000000..68d8d8219a
--- /dev/null
+++ b/toolkit/components/aboutperformance/content/aboutPerformance.css
@@ -0,0 +1,209 @@
+@import url("chrome://global/skin/in-content/common.css");
+
+html {
+  background-color: var(--in-content-page-background);
+}
+body {
+  overflow-x: hidden;
+}
+#dispatch-table {
+  -moz-user-select: none;
+  font-size: 1em;
+  border-spacing: 0;
+  background-color: var(--in-content-box-background);
+  margin: 0;
+  position: absolute;
+  top: 0;
+  left: 0;
+  width: 100%;
+  height: 100%;
+  min-width: 40em;
+}
+
+/* Avoid scrolling the header */
+#dispatch-tbody {
+  display: block;
+  margin-top: 2em;
+}
+#dispatch-thead {
+  position: fixed;
+  z-index: 1;
+  height: 2em;
+  border-bottom: 1px solid var(--in-content-border-color);
+  min-width: 40em;
+  background-color: var(--in-content-box-background);
+}
+tr {
+  display: table;
+  table-layout: fixed;
+  width: 100%;
+}
+td:nth-child(2) {
+  width: 8em;
+}
+td:nth-child(3) {
+  width: 12em;
+}
+td:nth-child(4) {
+  width: 5em;
+}
+#dispatch-tbody td:nth-child(4) {
+  text-align: end;
+}
+td:nth-child(5) {
+  width: 20px;
+}
+
+/* Show action icons on selected or hovered rows */
+tr:-moz-any([selected], :hover) > td > .action-icon {
+  padding: 1px 10px;
+  opacity: 1;
+}
+/* The action icons have a relative position, so that we can use
+ * absolutely positioned ::before and ::after pseudo elements.
+ * ::before is used to display the square background on hover/active
+ * ::after is used to display the icons as a background that can be
+ * flipped using a CSS transform in RTL mode. */
+.action-icon {
+  position: relative;
+  opacity: 0;
+}
+/* Ensure both pseudo elements have the same size and position. */
+.action-icon::before, .action-icon::after {
+  height: 200%;
+  position: absolute;
+  top: -50%;
+  left: -3px;
+  padding-left: 13px;
+  padding-right: 13px;
+}
+
+/* square background */
+.action-icon::before {
+  content: "";
+  background-color: currentColor;
+  opacity: 0;
+}
+.action-icon:hover::before {
+  opacity: 0.1;
+}
+.action-icon:hover:active::before {
+  opacity: 0.2;
+}
+
+/* icons */
+.action-icon::after {
+  -moz-context-properties: fill, fill-opacity;
+  fill-opacity: 0;
+  background-repeat: no-repeat;
+  background-position: center;
+  fill: currentColor;
+  line-height: 100%;
+}
+.addon-icon::after {
+  content: url("chrome://global/skin/icons/shortcut.svg");
+  top: 2px;
+  left: -11px;
+  width: 16px;
+}
+.addon-icon:dir(rtl)::after {
+  transform: scaleX(-1);
+}
+.close-icon::after {
+  content: url("chrome://global/skin/icons/close.svg");
+  height: 100%;
+  top: 0;
+  left: -13px;
+  transform: scale(1.2);
+}
+
+#dispatch-thead > tr {
+  height: inherit;
+}
+
+#dispatch-thead > tr > td {
+  border: none;
+  background-color: var(--in-content-box-background-hover);
+}
+#dispatch-thead > tr > td:not(:first-child) {
+  border-inline-start-width: 1px;
+  border-inline-start-style: solid;
+  border-image: linear-gradient(transparent 0%, transparent 20%, #c1c1c1 20%, #c1c1c1 80%, transparent 80%, transparent 100%) 1 1;
+  border-bottom: 1px solid var(--in-content-border-color);
+}
+td {
+  padding: 5px 10px;
+  min-height: 2em;
+  color: var(--in-content-text-color);
+  max-width: 70vw;
+  overflow: hidden;
+  white-space: nowrap;
+}
+#dispatch-tbody > tr > td:first-child {
+  text-overflow: ellipsis;
+  padding-inline-start: 32px;
+  background-repeat: no-repeat;
+  background-size: 16px 16px;
+  background-position-y: center;
+  -moz-context-properties: fill;
+  fill: currentColor;
+}
+#dispatch-tbody > tr > td.root{
+  background-position-x: left 36px;
+  padding-inline-start: 62px;
+}
+#dispatch-tbody > tr > td.root:dir(rtl) {
+  background-position-x: right 36px;
+}
+.twisty {
+  margin-inline-start: -62px;
+  margin-inline-end: 26px;
+  padding-inline-end: 18px;
+  padding-inline-start: 18px;
+  position: relative;
+}
+/* Putting the background image in a positioned pseudo element lets us
+ * use CSS transforms on the background image, which we need for rtl. */
+.twisty::before {
+  content: url("chrome://global/skin/icons/twisty-collapsed.svg");
+  position: absolute;
+  display: block;
+  line-height: 50%;
+  top: 4px; /* Half the image's height */
+  width: 100%;
+  left: 0;
+  text-align: center;
+  -moz-context-properties: fill;
+  fill: currentColor;
+}
+.twisty:dir(rtl)::before {
+  transform: scaleX(-1);
+}
+.twisty.open::before {
+  content: url("chrome://global/skin/icons/twisty-expanded.svg");
+}
+#dispatch-tbody > tr > td.indent {
+  padding-inline-start: 88px;
+  background-position-x: left 62px;
+}
+#dispatch-tbody > tr > td.indent:dir(rtl) {
+  background-position-x: right 62px;
+}
+#dispatch-tbody > tr > td.tracker {
+  background-image: url("chrome://browser/skin/controlcenter/trackers.svg");
+  -moz-context-properties: fill;
+  fill: rgb(224, 41, 29);
+}
+#dispatch-tbody > tr > td.worker {
+  background-image: url("chrome://devtools/skin/images/debugging-workers.svg");
+  -moz-context-properties: fill;
+  fill: #808080;
+}
+
+#dispatch-tbody > tr[selected] > td {
+  background-color: var(--in-content-item-selected);
+  color: var(--in-content-selected-text);
+}
+#dispatch-tbody > tr:hover {
+  background-color: var(--in-content-item-hover);
+}
diff --git a/toolkit/components/aboutperformance/content/aboutPerformance.js b/toolkit/components/aboutperformance/content/aboutPerformance.js
index 409c0e5275..bdc829b846 100644
--- a/toolkit/components/aboutperformance/content/aboutPerformance.js
+++ b/toolkit/components/aboutperformance/content/aboutPerformance.js
@@ -902,7 +902,7 @@ var Control = {
   },
 };
 
-var go = async function() {
+window.onload = async function() {
   Control.init();
 
   let addons = await AddonManager.getAddonsByTypes(["extension"]);
diff --git a/toolkit/components/aboutperformance/content/aboutPerformance.xhtml b/toolkit/components/aboutperformance/content/aboutPerformance.xhtml
index 1ec6722b36..a242b3e0ce 100644
--- a/toolkit/components/aboutperformance/content/aboutPerformance.xhtml
+++ b/toolkit/components/aboutperformance/content/aboutPerformance.xhtml
@@ -6,6 +6,7 @@
 
 <html xmlns="http://www.w3.org/1999/xhtml">
   <head>
+    <meta http-equiv="Content-Security-Policy" content="default-src chrome:;img-src data:" />
     <title data-l10n-id="about-performance-title"/>
     <link rel="icon" type="image/svg+xml" id="favicon"
           href="chrome://global/skin/icons/performance.svg"/>
@@ -13,219 +14,9 @@
           type="text/css"/>
     <link rel="localization" href="toolkit/about/aboutPerformance.ftl"/>
     <script src="chrome://global/content/aboutPerformance.js"></script>
-    <style>
-      @import url("chrome://global/skin/in-content/common.css");
-
-      html {
-        background-color: var(--in-content-page-background);
-      }
-      body {
-        overflow-x: hidden;
-      }
-      #dispatch-table {
-        -moz-user-select: none;
-        font-size: 1em;
-        border-spacing: 0;
-        background-color: var(--in-content-box-background);
-        margin: 0;
-        position: absolute;
-        top: 0;
-        left: 0;
-        width: 100%;
-        height: 100%;
-        min-width: 40em;
-      }
-
-      /* Avoid scrolling the header */
-      #dispatch-tbody {
-        display: block;
-        margin-top: 2em;
-      }
-      #dispatch-thead {
-        position: fixed;
-        z-index: 1;
-        height: 2em;
-        border-bottom: 1px solid var(--in-content-border-color);
-        min-width: 40em;
-        background-color: var(--in-content-box-background);
-      }
-      tr {
-        display: table;
-        table-layout: fixed;
-        width: 100%;
-      }
-      td:nth-child(2) {
-        width: 8em;
-      }
-      td:nth-child(3) {
-        width: 12em;
-      }
-      td:nth-child(4) {
-        width: 5em;
-      }
-      #dispatch-tbody td:nth-child(4) {
-        text-align: end;
-      }
-      td:nth-child(5) {
-        width: 20px;
-      }
-
-      /* Show action icons on selected or hovered rows */
-      tr:-moz-any([selected], :hover) > td > .action-icon {
-        padding: 1px 10px;
-        opacity: 1;
-      }
-      /* The action icons have a relative position, so that we can use
-       * absolutely positioned ::before and ::after pseudo elements.
-       * ::before is used to display the square background on hover/active
-       * ::after is used to display the icons as a background that can be
-       * flipped using a CSS transform in RTL mode. */
-      .action-icon {
-        position: relative;
-        opacity: 0;
-      }
-      /* Ensure both pseudo elements have the same size and position. */
-      .action-icon::before, .action-icon::after {
-        height: 200%;
-        position: absolute;
-        top: -50%;
-        left: -3px;
-        padding-left: 13px;
-        padding-right: 13px;
-      }
-
-      /* square background */
-      .action-icon::before {
-        content: "";
-        background-color: currentColor;
-        opacity: 0;
-      }
-      .action-icon:hover::before {
-        opacity: 0.1;
-      }
-      .action-icon:hover:active::before {
-        opacity: 0.2;
-      }
-
-      /* icons */
-      .action-icon::after {
-        -moz-context-properties: fill, fill-opacity;
-        fill-opacity: 0;
-        background-repeat: no-repeat;
-        background-position: center;
-        fill: currentColor;
-        line-height: 100%;
-      }
-      .addon-icon::after {
-        content: url("chrome://global/skin/icons/shortcut.svg");
-        top: 2px;
-        left: -11px;
-        width: 16px;
-      }
-      .addon-icon:dir(rtl)::after {
-        transform: scaleX(-1);
-      }
-      .close-icon::after {
-        content: url("chrome://global/skin/icons/close.svg");
-        height: 100%;
-        top: 0;
-        left: -13px;
-        transform: scale(1.2);
-      }
-
-      #dispatch-thead > tr {
-        height: inherit;
-      }
-
-      #dispatch-thead > tr > td {
-        border: none;
-        background-color: var(--in-content-box-background-hover);
-      }
-      #dispatch-thead > tr > td:not(:first-child) {
-        border-inline-start-width: 1px;
-        border-inline-start-style: solid;
-        border-image: linear-gradient(transparent 0%, transparent 20%, #c1c1c1 20%, #c1c1c1 80%, transparent 80%, transparent 100%) 1 1;
-        border-bottom: 1px solid var(--in-content-border-color);
-      }
-      td {
-        padding: 5px 10px;
-        min-height: 2em;
-        color: var(--in-content-text-color);
-        max-width: 70vw;
-        overflow: hidden;
-        white-space: nowrap;
-      }
-      #dispatch-tbody > tr > td:first-child {
-        text-overflow: ellipsis;
-        padding-inline-start: 32px;
-        background-repeat: no-repeat;
-        background-size: 16px 16px;
-        background-position-y: center;
-        -moz-context-properties: fill;
-        fill: currentColor;
-      }
-      #dispatch-tbody > tr > td.root{
-        background-position-x: left 36px;
-        padding-inline-start: 62px;
-      }
-      #dispatch-tbody > tr > td.root:dir(rtl) {
-        background-position-x: right 36px;
-      }
-      .twisty {
-        margin-inline-start: -62px;
-        margin-inline-end: 26px;
-        padding-inline-end: 18px;
-        padding-inline-start: 18px;
-        position: relative;
-      }
-      /* Putting the background image in a positioned pseudo element lets us
-       * use CSS transforms on the background image, which we need for rtl. */
-      .twisty::before {
-        content: url("chrome://global/skin/icons/twisty-collapsed.svg");
-        position: absolute;
-        display: block;
-        line-height: 50%;
-        top: 4px; /* Half the image's height */
-        width: 100%;
-        left: 0;
-        text-align: center;
-        -moz-context-properties: fill;
-        fill: currentColor;
-      }
-      .twisty:dir(rtl)::before {
-        transform: scaleX(-1);
-      }
-      .twisty.open::before {
-        content: url("chrome://global/skin/icons/twisty-expanded.svg");
-      }
-      #dispatch-tbody > tr > td.indent {
-        padding-inline-start: 88px;
-        background-position-x: left 62px;
-      }
-      #dispatch-tbody > tr > td.indent:dir(rtl) {
-        background-position-x: right 62px;
-      }
-      #dispatch-tbody > tr > td.tracker {
-        background-image: url("chrome://browser/skin/controlcenter/trackers.svg");
-        -moz-context-properties: fill;
-        fill: rgb(224, 41, 29);
-      }
-      #dispatch-tbody > tr > td.worker {
-        background-image: url("chrome://devtools/skin/images/debugging-workers.svg");
-        -moz-context-properties: fill;
-        fill: #808080;
-      }
-
-      #dispatch-tbody > tr[selected] > td {
-        background-color: var(--in-content-item-selected);
-        color: var(--in-content-selected-text);
-      }
-      #dispatch-tbody > tr:hover {
-        background-color: var(--in-content-item-hover);
-      }
-    </style>
+    <link rel="stylesheet" href="chrome://global/content/aboutPerformance.css"/>
   </head>
-  <body onload="go()">
+  <body>
     <table id="dispatch-table">
       <thead id="dispatch-thead">
         <tr>
diff --git a/toolkit/components/aboutperformance/jar.mn b/toolkit/components/aboutperformance/jar.mn
index 96e046d8ee..2f3577616f 100644
--- a/toolkit/components/aboutperformance/jar.mn
+++ b/toolkit/components/aboutperformance/jar.mn
@@ -5,3 +5,4 @@
 toolkit.jar:
   content/global/aboutPerformance.xhtml               (content/aboutPerformance.xhtml)
   content/global/aboutPerformance.js                  (content/aboutPerformance.js)
+  content/global/aboutPerformance.css                 (content/aboutPerformance.css)
diff --git a/toolkit/components/antitracking/AntiTrackingCommon.cpp b/toolkit/components/antitracking/AntiTrackingCommon.cpp
index 759a6e9a60..8b02617421 100644
--- a/toolkit/components/antitracking/AntiTrackingCommon.cpp
+++ b/toolkit/components/antitracking/AntiTrackingCommon.cpp
@@ -11,7 +11,6 @@
 #include "mozilla/IntegerPrintfMacros.h"
 #include "mozilla/Logging.h"
 #include "mozilla/MruCache.h"
-#include "mozilla/Pair.h"
 #include "mozilla/ScopeExit.h"
 #include "mozilla/StaticPrefs_extensions.h"
 #include "mozilla/StaticPrefs_privacy.h"
@@ -467,8 +466,8 @@ void ReportUnblockingToConsole(
   nsresult rv = NS_DispatchToCurrentThreadQueue(
       NS_NewRunnableFunction(
           "ReportUnblockingToConsoleDelayed",
-          [doc, principal, trackingOrigin, sourceLine, lineNumber,
-           columnNumber, aReason]() {
+          [doc, principal, trackingOrigin, sourceLine, lineNumber, columnNumber,
+           aReason]() {
             nsAutoString origin;
             nsresult rv = nsContentUtils::GetUTFOrigin(principal, origin);
             if (NS_WARN_IF(NS_FAILED(rv))) {
@@ -493,8 +492,9 @@ void ReportUnblockingToConsole(
             }
 
             nsContentUtils::ReportToConsole(
-                nsIScriptError::warningFlag, NS_LITERAL_CSTRING("Content Blocking"),
-                doc, nsContentUtils::eNECKO_PROPERTIES, messageWithSameOrigin,
+                nsIScriptError::warningFlag,
+                NS_LITERAL_CSTRING("Content Blocking"), doc,
+                nsContentUtils::eNECKO_PROPERTIES, messageWithSameOrigin,
                 params, nullptr, sourceLine, lineNumber, columnNumber);
           }),
       kMaxConsoleOutputDelayMs, EventQueuePriority::Idle);
@@ -529,19 +529,19 @@ already_AddRefed<nsPIDOMWindowOuter> GetTopWindow(nsPIDOMWindowInner* aWindow) {
 
 class TemporaryAccessGrantCacheKey : public PLDHashEntryHdr {
  public:
-  typedef Pair<nsCOMPtr<nsIPrincipal>, nsCString> KeyType;
+  typedef std::pair<nsCOMPtr<nsIPrincipal>, nsCString> KeyType;
   typedef const KeyType* KeyTypePointer;
 
   explicit TemporaryAccessGrantCacheKey(KeyTypePointer aKey)
-      : mPrincipal(aKey->first()), mType(aKey->second()) {}
+      : mPrincipal(aKey->first), mType(aKey->second) {}
   TemporaryAccessGrantCacheKey(TemporaryAccessGrantCacheKey&& aOther) = default;
 
   ~TemporaryAccessGrantCacheKey() = default;
 
-  KeyType GetKey() const { return MakePair(mPrincipal, mType); }
+  KeyType GetKey() const { return std::make_pair(mPrincipal, mType); }
   bool KeyEquals(KeyTypePointer aKey) const {
-    return !!mPrincipal == !!aKey->first() && mType == aKey->second() &&
-           (mPrincipal ? (mPrincipal->Equals(aKey->first())) : true);
+    return !!mPrincipal == !!aKey->first && mType == aKey->second &&
+           (mPrincipal ? (mPrincipal->Equals(aKey->first)) : true);
   }
 
   static KeyTypePointer KeyToPointer(KeyType& aKey) { return &aKey; }
@@ -550,9 +550,9 @@ class TemporaryAccessGrantCacheKey : public PLDHashEntryHdr {
       return 0;
     }
 
-    BasePrincipal* bp = BasePrincipal::Cast(aKey->first());
+    BasePrincipal* bp = BasePrincipal::Cast(aKey->first);
     return HashGeneric(bp->GetOriginNoSuffixHash(), bp->GetOriginSuffixHash(),
-                       HashString(aKey->second()));
+                       HashString(aKey->second));
   }
 
   enum { ALLOW_MEMMOVE = true };
@@ -575,8 +575,8 @@ class TemporaryAccessGrantObserver final : public nsIObserver {
       sObservers = MakeUnique<ObserversTable>();
     }
     Unused << sObservers
-                  ->LookupForAdd(MakePair(nsCOMPtr<nsIPrincipal>(aPrincipal),
-                                          nsCString(aType)))
+                  ->LookupForAdd(std::make_pair(
+                      nsCOMPtr<nsIPrincipal>(aPrincipal), nsCString(aType)))
                   .OrInsert([&]() -> nsITimer* {
                     // Only create a new observer if we don't have a matching
                     // entry in our hashtable.
@@ -641,7 +641,7 @@ TemporaryAccessGrantObserver::Observe(nsISupports* aSubject, const char* aTopic,
     Unused << mPM->RemoveFromPrincipal(mPrincipal, mType);
 
     MOZ_ASSERT(sObservers);
-    sObservers->Remove(MakePair(mPrincipal, mType));
+    sObservers->Remove(std::make_pair(mPrincipal, mType));
   } else if (strcmp(aTopic, NS_XPCOM_SHUTDOWN_OBSERVER_ID) == 0) {
     nsCOMPtr<nsIObserverService> observerService =
         mozilla::services::GetObserverService();
@@ -1763,23 +1763,23 @@ nsresult AntiTrackingCommon::IsOnContentBlockingAllowList(
 
   // Check both the normal mode and private browsing mode user override
   // permissions.
-  Pair<const nsLiteralCString, bool> types[] = {
+  std::pair<const nsLiteralCString, bool> types[] = {
       {NS_LITERAL_CSTRING("trackingprotection"), false},
       {NS_LITERAL_CSTRING("trackingprotection-pb"), true}};
 
   for (size_t i = 0; i < ArrayLength(types); ++i) {
-    if (aIsPrivateBrowsing != types[i].second()) {
+    if (aIsPrivateBrowsing != types[i].second) {
       continue;
     }
 
     uint32_t permissions = nsIPermissionManager::UNKNOWN_ACTION;
     nsresult rv = permManager->TestPermissionFromPrincipal(
-        aTopWinPrincipal, types[i].first(), &permissions);
+        aTopWinPrincipal, types[i].first, &permissions);
     NS_ENSURE_SUCCESS(rv, rv);
 
     if (permissions == nsIPermissionManager::ALLOW_ACTION) {
       aIsAllowListed = true;
-      LOG(("Found user override type %s", types[i].first().get()));
+      LOG(("Found user override type %s", types[i].first.get()));
       // Stop checking the next permisson type if we decided to override.
       break;
     }
diff --git a/toolkit/components/backgroundhangmonitor/BackgroundHangMonitor.cpp b/toolkit/components/backgroundhangmonitor/BackgroundHangMonitor.cpp
index 07ad2f465a..f17f032f81 100644
--- a/toolkit/components/backgroundhangmonitor/BackgroundHangMonitor.cpp
+++ b/toolkit/components/backgroundhangmonitor/BackgroundHangMonitor.cpp
@@ -492,9 +492,10 @@ void BackgroundHangThread::ReportHang(TimeDuration aHangTime) {
 
   // If the profiler is enabled, add a marker.
 #ifdef MOZ_GECKO_PROFILER
-  if (profiler_is_active()) {
+  if (profiler_can_accept_markers()) {
     TimeStamp endTime = TimeStamp::Now();
     TimeStamp startTime = endTime - aHangTime;
+    AUTO_PROFILER_STATS(add_marker_with_HangMarkerPayload);
     profiler_add_marker_for_thread(
         mStackHelper.GetThreadId(), JS::ProfilingCategoryPair::OTHER,
         "BHR-detected hang", MakeUnique<HangMarkerPayload>(startTime, endTime));
diff --git a/toolkit/components/backgroundhangmonitor/tests/child_cause_hang.js b/toolkit/components/backgroundhangmonitor/tests/child_cause_hang.js
index 7c468b93e9..f48b3b94dc 100644
--- a/toolkit/components/backgroundhangmonitor/tests/child_cause_hang.js
+++ b/toolkit/components/backgroundhangmonitor/tests/child_cause_hang.js
@@ -11,7 +11,7 @@ function ensureProfilerInitialized() {
     return false;
   }
   let features = ["stackwalk"];
-  Services.profiler.StartProfiler(1000, 10, features, features.length);
+  Services.profiler.StartProfiler(1000, 10, features);
   Services.profiler.StopProfiler();
   return true;
 }
diff --git a/toolkit/components/backgroundhangmonitor/tests/test_BHRObserver.js b/toolkit/components/backgroundhangmonitor/tests/test_BHRObserver.js
index b5ef90c3bf..b00f68578d 100644
--- a/toolkit/components/backgroundhangmonitor/tests/test_BHRObserver.js
+++ b/toolkit/components/backgroundhangmonitor/tests/test_BHRObserver.js
@@ -14,7 +14,7 @@ function ensureProfilerInitialized() {
     return false;
   }
   let features = ["stackwalk"];
-  Services.profiler.StartProfiler(1000, 10, features, features.length);
+  Services.profiler.StartProfiler(1000, 10, features);
   Services.profiler.StopProfiler();
   return true;
 }
diff --git a/toolkit/components/build/components.conf b/toolkit/components/build/components.conf
index 2429c9d21e..58ad0dfaba 100644
--- a/toolkit/components/build/components.conf
+++ b/toolkit/components/build/components.conf
@@ -78,8 +78,10 @@ Classes = [
     },
     {
         'name': 'AppStartup',
+        'js_name': 'startup',
         'cid': '{7dd4d320-c84b-4624-8d45-7bb9b2356977}',
         'contract_ids': ['@mozilla.org/toolkit/app-startup;1'],
+        'interfaces': ['nsIAppStartup'],
         'type': 'nsAppStartup',
         'headers': ['/toolkit/components/startup/nsAppStartup.h'],
         'init_method': 'Init',
diff --git a/toolkit/components/captivedetect/CaptiveDetect.jsm b/toolkit/components/captivedetect/CaptiveDetect.jsm
index e9aef2ccaf..6e222129c5 100644
--- a/toolkit/components/captivedetect/CaptiveDetect.jsm
+++ b/toolkit/components/captivedetect/CaptiveDetect.jsm
@@ -511,13 +511,14 @@ CaptivePortalDetector.prototype = {
   },
 };
 
-/* globals debug: true */
 var debug;
 if (DEBUG) {
+  // eslint-disable-next-line no-global-assign
   debug = function(s) {
     dump("-*- CaptivePortalDetector component: " + s + "\n");
   };
 } else {
+  // eslint-disable-next-line no-global-assign
   debug = function(s) {};
 }
 
diff --git a/toolkit/components/cleardata/components.conf b/toolkit/components/cleardata/components.conf
index 15cfdafd66..2bd2fdb3d0 100644
--- a/toolkit/components/cleardata/components.conf
+++ b/toolkit/components/cleardata/components.conf
@@ -4,8 +4,10 @@
 
 Classes = [
     {
+        'js_name': 'clearData',
         'cid': '{0c06583d-7dd8-4293-b1a5-912205f779aa}',
         'contract_ids': ['@mozilla.org/clear-data-service;1'],
+        'interfaces': ['nsIClearDataService'],
         'jsm': 'resource://gre/modules/ClearDataService.jsm',
         'constructor': 'ClearDataService',
     },
diff --git a/toolkit/components/commandlines/nsCommandLine.cpp b/toolkit/components/commandlines/nsCommandLine.cpp
index 78f52496de..8d453a3e7d 100644
--- a/toolkit/components/commandlines/nsCommandLine.cpp
+++ b/toolkit/components/commandlines/nsCommandLine.cpp
@@ -99,9 +99,7 @@ nsCommandLine::RemoveArguments(int32_t aStart, int32_t aEnd) {
   NS_ENSURE_ARG_MIN(aStart, 0);
   NS_ENSURE_ARG_MAX(uint32_t(aEnd) + 1, mArgs.Length());
 
-  for (int32_t i = aEnd; i >= aStart; --i) {
-    mArgs.RemoveElementAt(i);
-  }
+  mArgs.RemoveElementsAt(mArgs.begin() + aStart, mArgs.begin() + aEnd + 1);
 
   return NS_OK;
 }
diff --git a/toolkit/components/crashes/CrashManager.jsm b/toolkit/components/crashes/CrashManager.jsm
index ebb526a015..a9c79d629c 100644
--- a/toolkit/components/crashes/CrashManager.jsm
+++ b/toolkit/components/crashes/CrashManager.jsm
@@ -21,7 +21,7 @@ const { TelemetryController } = ChromeUtils.import(
 ChromeUtils.import("resource://gre/modules/Timer.jsm", this);
 ChromeUtils.import("resource://gre/modules/XPCOMUtils.jsm", this);
 
-var EXPORTED_SYMBOLS = ["CrashManager"];
+var EXPORTED_SYMBOLS = ["CrashManager", "getCrashManager"];
 
 /**
  * How long to wait after application startup before crash event files are
@@ -1552,3 +1552,7 @@ XPCOMUtils.defineLazyGetter(this.CrashManager, "Singleton", function() {
 
   return gCrashManager;
 });
+
+function getCrashManager() {
+  return CrashManager.Singleton;
+}
diff --git a/toolkit/components/crashes/components.conf b/toolkit/components/crashes/components.conf
index ad28e46ab4..38414e0c2e 100644
--- a/toolkit/components/crashes/components.conf
+++ b/toolkit/components/crashes/components.conf
@@ -10,4 +10,11 @@ Classes = [
         'constructor': 'CrashService',
         'categories': {'profile-after-change': 'CrashService'},
     },
+    {
+        'js_name': 'crashmanager',
+        'cid': '{c887b6a9-a5eb-4566-a440-bebaea3e54fd}',
+        'contract_ids': ['@mozilla.org/crashmanager;1'],
+        'jsm': 'resource://gre/modules/CrashManager.jsm',
+        'constructor': 'getCrashManager',
+    },
 ]
diff --git a/toolkit/components/ctypes/tests/unit/test_jsctypes.js b/toolkit/components/ctypes/tests/unit/test_jsctypes.js
index 5b84dd4043..06645dc780 100644
--- a/toolkit/components/ctypes/tests/unit/test_jsctypes.js
+++ b/toolkit/components/ctypes/tests/unit/test_jsctypes.js
@@ -3952,6 +3952,7 @@ function run_variadic_tests(library) {
     ctypes.int32_t.ptr,
     ctypes.uint8_t,
     ctypes.uint8_t,
+    ctypes.int32_t.ptr,
     "..."
   );
   // Note that vector_add_va zeroes out result first.
diff --git a/toolkit/components/enterprisepolicies/EnterprisePolicies.jsm b/toolkit/components/enterprisepolicies/EnterprisePolicies.jsm
new file mode 100644
index 0000000000..0d615ed560
--- /dev/null
+++ b/toolkit/components/enterprisepolicies/EnterprisePolicies.jsm
@@ -0,0 +1,22 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+var EXPORTED_SYMBOLS = ["EnterprisePolicies"];
+
+function EnterprisePolicies() {
+  // eslint-disable-next-line mozilla/use-services
+  const appinfo = Cc["@mozilla.org/xre/app-info;1"].getService(
+    Ci.nsIXULRuntime
+  );
+  if (appinfo.processType == appinfo.PROCESS_TYPE_DEFAULT) {
+    const { EnterprisePoliciesManager } = ChromeUtils.import(
+      "resource://gre/modules/EnterprisePoliciesParent.jsm"
+    );
+    return new EnterprisePoliciesManager();
+  }
+  const { EnterprisePoliciesManagerContent } = ChromeUtils.import(
+    "resource://gre/modules/EnterprisePoliciesContent.jsm"
+  );
+  return new EnterprisePoliciesManagerContent();
+}
diff --git a/toolkit/components/enterprisepolicies/EnterprisePolicies.manifest b/toolkit/components/enterprisepolicies/EnterprisePolicies.manifest
deleted file mode 100644
index b3a542b7fd..0000000000
--- a/toolkit/components/enterprisepolicies/EnterprisePolicies.manifest
+++ /dev/null
@@ -1,5 +0,0 @@
-component {ea4e1414-779b-458b-9d1f-d18e8efbc145} EnterprisePolicies.js process=main
-contract @mozilla.org/enterprisepolicies;1 {ea4e1414-779b-458b-9d1f-d18e8efbc145} process=main
-
-component {dc6358f8-d167-4566-bf5b-4350b5e6a7a2} EnterprisePoliciesContent.js process=content
-contract @mozilla.org/enterprisepolicies;1 {dc6358f8-d167-4566-bf5b-4350b5e6a7a2} process=content
diff --git a/toolkit/components/enterprisepolicies/EnterprisePoliciesContent.js b/toolkit/components/enterprisepolicies/EnterprisePoliciesContent.jsm
similarity index 55%
rename from toolkit/components/enterprisepolicies/EnterprisePoliciesContent.js
rename to toolkit/components/enterprisepolicies/EnterprisePoliciesContent.jsm
index c2efb692cc..367e7a5f85 100644
--- a/toolkit/components/enterprisepolicies/EnterprisePoliciesContent.js
+++ b/toolkit/components/enterprisepolicies/EnterprisePoliciesContent.jsm
@@ -2,35 +2,26 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-const { XPCOMUtils } = ChromeUtils.import(
-  "resource://gre/modules/XPCOMUtils.jsm"
-);
+var EXPORTED_SYMBOLS = ["EnterprisePoliciesManagerContent"];
+
 const { Services } = ChromeUtils.import("resource://gre/modules/Services.jsm");
 
-function EnterprisePoliciesManagerContent() {}
-
-EnterprisePoliciesManagerContent.prototype = {
-  classID: Components.ID("{dc6358f8-d167-4566-bf5b-4350b5e6a7a2}"),
-  QueryInterface: ChromeUtils.generateQI([Ci.nsIEnterprisePolicies]),
-  _xpcom_factory: XPCOMUtils.generateSingletonFactory(
-    EnterprisePoliciesManagerContent
-  ),
-
+class EnterprisePoliciesManagerContent {
   get status() {
     return (
       Services.cpmm.sharedData.get("EnterprisePolicies:Status") ||
       Ci.nsIEnterprisePolicies.INACTIVE
     );
-  },
+  }
 
   isAllowed(feature) {
     let disallowedFeatures = Services.cpmm.sharedData.get(
       "EnterprisePolicies:DisallowedFeatures"
     );
     return !(disallowedFeatures && disallowedFeatures.has(feature));
-  },
-};
+  }
+}
 
-this.NSGetFactory = XPCOMUtils.generateNSGetFactory([
-  EnterprisePoliciesManagerContent,
-]);
+EnterprisePoliciesManagerContent.prototype.QueryInterface = ChromeUtils.generateQI(
+  [Ci.nsIEnterprisePolicies]
+);
diff --git a/toolkit/components/enterprisepolicies/EnterprisePolicies.js b/toolkit/components/enterprisepolicies/EnterprisePoliciesParent.jsm
similarity index 98%
rename from toolkit/components/enterprisepolicies/EnterprisePolicies.js
rename to toolkit/components/enterprisepolicies/EnterprisePoliciesParent.jsm
index dd26f75ed2..0ff41fce38 100644
--- a/toolkit/components/enterprisepolicies/EnterprisePolicies.js
+++ b/toolkit/components/enterprisepolicies/EnterprisePoliciesParent.jsm
@@ -2,6 +2,8 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
+var EXPORTED_SYMBOLS = ["EnterprisePoliciesManager"];
+
 const { XPCOMUtils } = ChromeUtils.import(
   "resource://gre/modules/XPCOMUtils.jsm"
 );
@@ -77,15 +79,11 @@ function EnterprisePoliciesManager() {
 }
 
 EnterprisePoliciesManager.prototype = {
-  classID: Components.ID("{ea4e1414-779b-458b-9d1f-d18e8efbc145}"),
   QueryInterface: ChromeUtils.generateQI([
     Ci.nsIObserver,
     Ci.nsISupportsWeakReference,
     Ci.nsIEnterprisePolicies,
   ]),
-  _xpcom_factory: XPCOMUtils.generateSingletonFactory(
-    EnterprisePoliciesManager
-  ),
 
   _initialize() {
     let provider = this._chooseProvider();
@@ -622,6 +620,3 @@ class macOSPoliciesProvider {
     return this._failed;
   }
 }
-
-var components = [EnterprisePoliciesManager];
-this.NSGetFactory = XPCOMUtils.generateNSGetFactory(components);
diff --git a/toolkit/components/enterprisepolicies/components.conf b/toolkit/components/enterprisepolicies/components.conf
new file mode 100644
index 0000000000..c561ed2df7
--- /dev/null
+++ b/toolkit/components/enterprisepolicies/components.conf
@@ -0,0 +1,14 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+Classes = [
+    {
+        'js_name': 'policies',
+        'cid': '{49e8d8ef-a713-492a-a3d2-5c9dad4ce2e5}',
+        'contract_ids': ['@mozilla.org/enterprisepolicies;1'],
+        'interfaces': ['nsIEnterprisePolicies'],
+        'jsm': 'resource://gre/modules/EnterprisePolicies.jsm',
+        'constructor': 'EnterprisePolicies',
+    },
+]
diff --git a/toolkit/components/enterprisepolicies/moz.build b/toolkit/components/enterprisepolicies/moz.build
index cc24eab9c7..b5342108d3 100644
--- a/toolkit/components/enterprisepolicies/moz.build
+++ b/toolkit/components/enterprisepolicies/moz.build
@@ -16,10 +16,14 @@ TEST_DIRS += [
 ]
 
 if CONFIG['MOZ_WIDGET_TOOLKIT'] != "android":
-    EXTRA_COMPONENTS += [
-        'EnterprisePolicies.js',
-        'EnterprisePolicies.manifest',
-        'EnterprisePoliciesContent.js',
+    EXTRA_JS_MODULES += [
+        'EnterprisePolicies.jsm',
+        'EnterprisePoliciesContent.jsm',
+        'EnterprisePoliciesParent.jsm',
+    ]
+
+    XPCOM_MANIFESTS += [
+        'components.conf',
     ]
 
 if CONFIG['MOZ_WIDGET_TOOLKIT'] == 'windows':
diff --git a/toolkit/components/extensions/Extension.jsm b/toolkit/components/extensions/Extension.jsm
index b2c5d4a256..0550caca7c 100644
--- a/toolkit/components/extensions/Extension.jsm
+++ b/toolkit/components/extensions/Extension.jsm
@@ -12,7 +12,6 @@ var EXPORTED_SYMBOLS = [
 ];
 
 /* exported Extension, ExtensionData */
-/* globals Extension ExtensionData */
 
 /*
  * This file is the main entry point for extensions. When an extension
@@ -308,7 +307,7 @@ var UninstallObserver = {
 
       // If LSNG is not enabled, we need to clear localStorage explicitly using
       // the old API.
-      if (!Services.lsm.nextGenLocalStorageEnabled) {
+      if (!Services.domStorageManager.nextGenLocalStorageEnabled) {
         // Clear localStorage created by the extension
         let storage = Services.domStorageManager.getStorage(
           null,
diff --git a/toolkit/components/extensions/ExtensionContent.jsm b/toolkit/components/extensions/ExtensionContent.jsm
index 4220bf33bd..591cae7e01 100644
--- a/toolkit/components/extensions/ExtensionContent.jsm
+++ b/toolkit/components/extensions/ExtensionContent.jsm
@@ -5,8 +5,6 @@
 
 var EXPORTED_SYMBOLS = ["ExtensionContent"];
 
-/* globals ExtensionContent */
-
 const { Services } = ChromeUtils.import("resource://gre/modules/Services.jsm");
 const { XPCOMUtils } = ChromeUtils.import(
   "resource://gre/modules/XPCOMUtils.jsm"
diff --git a/toolkit/components/extensions/ExtensionPageChild.jsm b/toolkit/components/extensions/ExtensionPageChild.jsm
index e6e3f81415..4f7d98269b 100644
--- a/toolkit/components/extensions/ExtensionPageChild.jsm
+++ b/toolkit/components/extensions/ExtensionPageChild.jsm
@@ -292,6 +292,10 @@ class ExtensionPageContextChild extends ExtensionBaseContextChild {
   constructor(extension, params) {
     super(extension, Object.assign(params, { envType: "addon_child" }));
 
+    if (this.viewType == "background") {
+      initializeBackgroundPage(this);
+    }
+
     this.extension.views.add(this);
   }
 
@@ -319,10 +323,6 @@ defineLazyGetter(
 
     this.callOnClose(childManager);
 
-    if (this.viewType == "background") {
-      initializeBackgroundPage(this);
-    }
-
     return childManager;
   }
 );
diff --git a/toolkit/components/extensions/MatchPattern.h b/toolkit/components/extensions/MatchPattern.h
index fcf3590238..b8a544fbb0 100644
--- a/toolkit/components/extensions/MatchPattern.h
+++ b/toolkit/components/extensions/MatchPattern.h
@@ -5,6 +5,8 @@
 #ifndef mozilla_extensions_MatchPattern_h
 #define mozilla_extensions_MatchPattern_h
 
+#include <utility>
+
 #include "mozilla/dom/BindingDeclarations.h"
 #include "mozilla/dom/MatchPatternBinding.h"
 #include "mozilla/extensions/MatchGlob.h"
@@ -94,11 +96,11 @@ class AtomSet final : public RefCounted<AtomSet> {
     }
   }
 
-  auto begin() const -> decltype(DeclVal<const ArrayType>().begin()) {
+  auto begin() const -> decltype(std::declval<const ArrayType>().begin()) {
     return mElems.begin();
   }
 
-  auto end() const -> decltype(DeclVal<const ArrayType>().end()) {
+  auto end() const -> decltype(std::declval<const ArrayType>().end()) {
     return mElems.end();
   }
 
diff --git a/toolkit/components/extensions/parent/ext-geckoProfiler.js b/toolkit/components/extensions/parent/ext-geckoProfiler.js
index d316be3aa8..416e495564 100644
--- a/toolkit/components/extensions/parent/ext-geckoProfiler.js
+++ b/toolkit/components/extensions/parent/ext-geckoProfiler.js
@@ -91,9 +91,7 @@ this.geckoProfiler = class extends ExtensionAPI {
               bufferSize,
               interval,
               features,
-              features.length,
               threads,
-              threads.length,
               windowLength
             );
           } else {
@@ -101,9 +99,7 @@ this.geckoProfiler = class extends ExtensionAPI {
               bufferSize,
               interval,
               features,
-              features.length,
               [],
-              0,
               windowLength
             );
           }
@@ -125,6 +121,29 @@ this.geckoProfiler = class extends ExtensionAPI {
           Services.profiler.ResumeSampling();
         },
 
+        async dumpProfileToFile(fileName) {
+          if (!Services.profiler.IsActive()) {
+            throw new ExtensionError(
+              "The profiler is stopped. " +
+                "You need to start the profiler before you can capture a profile."
+            );
+          }
+
+          if (fileName.includes("\\") || fileName.includes("/")) {
+            throw new ExtensionError("Path cannot contain a subdirectory.");
+          }
+
+          let fragments = [OS.Constants.Path.profileDir, "profiler", fileName];
+          let filePath = OS.Path.join(...fragments);
+
+          try {
+            await Services.profiler.dumpProfileToFileAsync(filePath);
+          } catch (e) {
+            Cu.reportError(e);
+            throw new ExtensionError(`Dumping profile to ${filePath} failed.`);
+          }
+        },
+
         async getProfile() {
           if (!Services.profiler.IsActive()) {
             throw new ExtensionError(
diff --git a/toolkit/components/extensions/parent/ext-toolkit.js b/toolkit/components/extensions/parent/ext-toolkit.js
index f3ad585afa..43b3bd0968 100644
--- a/toolkit/components/extensions/parent/ext-toolkit.js
+++ b/toolkit/components/extensions/parent/ext-toolkit.js
@@ -6,7 +6,7 @@
             getContainerForCookieStoreId,
             isValidCookieStoreId, isContainerCookieStoreId,
             EventManager, URL */
-/* global getCookieStoreIdForTab:false, getCookieStoreIdForOriginAttributes:false,
+/* global getCookieStoreIdForTab:false,
           getCookieStoreIdForContainer:false,
           getContainerForCookieStoreId: false,
           isValidCookieStoreId:false, isContainerCookieStoreId:false,
diff --git a/toolkit/components/extensions/schemas/geckoProfiler.json b/toolkit/components/extensions/schemas/geckoProfiler.json
index 6df6f3e023..b88384baec 100644
--- a/toolkit/components/extensions/schemas/geckoProfiler.json
+++ b/toolkit/components/extensions/schemas/geckoProfiler.json
@@ -27,7 +27,6 @@
           "js",
           "leaf",
           "mainthreadio",
-          "memory",
           "privacy",
           "responsiveness",
           "screenshots",
@@ -35,9 +34,10 @@
           "stackwalk",
           "tasktracer",
           "threads",
-          "trackopts",
           "jstracer",
-          "jsallocations"
+          "jsallocations",
+          "nostacksampling",
+          "nativeallocations"
         ]
       },
       {
@@ -113,6 +113,19 @@
         "async": true,
         "parameters": []
       },
+      {
+        "name": "dumpProfileToFile",
+        "type": "function",
+        "description": "Gathers the profile data from the current profiling session, and writes it to disk. The returned promise resolves to a path that locates the created file.",
+        "async": true,
+        "parameters": [
+          {
+            "type": "string",
+            "name": "fileName",
+            "description": "The name of the file inside the profile/profiler directory"
+          }
+        ]
+      },
       {
         "name": "getProfile",
         "type": "function",
diff --git a/toolkit/components/extensions/test/browser/browser_ext_downloads_referrer.js b/toolkit/components/extensions/test/browser/browser_ext_downloads_referrer.js
index b2931e0b6f..a6e8b54041 100644
--- a/toolkit/components/extensions/test/browser/browser_ext_downloads_referrer.js
+++ b/toolkit/components/extensions/test/browser/browser_ext_downloads_referrer.js
@@ -1,6 +1,3 @@
-/* -*- Mode: indent-tabs-mode: nil; js-indent-level: 2 -*- */
-/* vim: set sts=2 sw=2 et tw=80: */
-
 "use strict";
 
 const { BrowserTestUtils } = ChromeUtils.import(
diff --git a/toolkit/components/extensions/test/browser/browser_ext_themes_additional_backgrounds_alignment.js b/toolkit/components/extensions/test/browser/browser_ext_themes_additional_backgrounds_alignment.js
index 537f1f9aa0..f265a724e5 100644
--- a/toolkit/components/extensions/test/browser/browser_ext_themes_additional_backgrounds_alignment.js
+++ b/toolkit/components/extensions/test/browser/browser_ext_themes_additional_backgrounds_alignment.js
@@ -1,7 +1,5 @@
 "use strict";
 
-/* globals InspectorUtils */
-
 // Case 1 - When there is a theme_frame image and additional_backgrounds_alignment is not specified.
 // So background-position should default to "right top"
 add_task(async function test_default_additional_backgrounds_alignment() {
diff --git a/toolkit/components/extensions/test/mochitest/head_unlimitedStorage.js b/toolkit/components/extensions/test/mochitest/head_unlimitedStorage.js
index 4f19730450..e2a899e05c 100644
--- a/toolkit/components/extensions/test/mochitest/head_unlimitedStorage.js
+++ b/toolkit/components/extensions/test/mochitest/head_unlimitedStorage.js
@@ -1,5 +1,3 @@
-/* -*- Mode: indent-tabs-mode: nil; js-indent-level: 2 -*- */
-/* vim: set sts=2 sw=2 et tw=80: */
 "use strict";
 
 /* exported checkSitePermissions */
diff --git a/toolkit/components/extensions/test/mochitest/test_ext_background_page.html b/toolkit/components/extensions/test/mochitest/test_ext_background_page.html
index 3107e09ec9..9cafd8a61a 100644
--- a/toolkit/components/extensions/test/mochitest/test_ext_background_page.html
+++ b/toolkit/components/extensions/test/mochitest/test_ext_background_page.html
@@ -1,83 +1,84 @@
 <!DOCTYPE HTML>
 <html>
-<head>
-  <title>WebExtension test</title>
-  <meta charset="utf-8">
-  <script src="/tests/SimpleTest/SimpleTest.js"></script>
-  <script src="/tests/SimpleTest/ExtensionTestUtils.js"></script>
-  <script type="text/javascript" src="head.js"></script>
-  <link rel="stylesheet" href="/tests/SimpleTest/test.css"/>
-</head>
-<body>
+  <head>
+    <title>WebExtension test</title>
+    <meta charset="utf-8">
+    <script src="/tests/SimpleTest/SimpleTest.js"></script>
+    <script src="/tests/SimpleTest/ExtensionTestUtils.js"></script>
+    <script src="head.js" type="text/javascript"></script>
+    <link href="/tests/SimpleTest/test.css" rel="stylesheet"/>
+  </head>
+  <body>
 
-<script type="text/javascript">
-"use strict";
+    <script type="text/javascript">
+      "use strict";
 
-/* eslint-disable mozilla/balanced-listeners */
+      /* eslint-disable mozilla/balanced-listeners */
 
-add_task(async function testAlertNotShownInBackgroundWindow() {
-  let extension = ExtensionTestUtils.loadExtension({
-    background: function() {
-      browser.test.log("background script executed");
+      add_task(async function testAlertNotShownInBackgroundWindow() {
+        let extension = ExtensionTestUtils.loadExtension({
+          background: function () {
+            alert("I am an alert in the background.");
 
-      alert("I am an alert in the background.");
+            browser.test.notifyPass("alertCalled");
+          }
+        });
 
-      browser.test.notifyPass("alertCalled");
-    },
-  });
+        let consoleOpened = loadChromeScript(() => {
+          const {sendAsyncMessage, assert} = this;
+          assert.ok(!Services.wm.getEnumerator("alert:alert").hasMoreElements(), "Alerts should not be present at the start of the test.");
 
-  let consoleOpened = loadChromeScript(() => {
-    const {sendAsyncMessage, assert} = this;
-    assert.ok(!Services.wm.getEnumerator("alert:alert").hasMoreElements(),
-              "Alerts should not be present at the start of the test.");
+          Services.obs.addObserver(function observer() {
+            sendAsyncMessage("web-console-created");
+            Services.obs.removeObserver(observer, "web-console-created");
+          }, "web-console-created");
+        });
+        let opened = consoleOpened.promiseOneMessage("web-console-created");
 
-    Services.obs.addObserver(function observer() {
-      sendAsyncMessage("web-console-created");
-      Services.obs.removeObserver(observer, "web-console-created");
-    }, "web-console-created");
-  });
-  let opened = consoleOpened.promiseOneMessage("web-console-created");
+        consoleMonitor.start([
+          {
+            message: /alert\(\) is not supported in background windows/
+          }, {
+            message: /I am an alert in the background/
+          }
+        ]);
 
-  consoleMonitor.start([{message: /alert\(\) is not supported in background windows/},
-                        {message: /I am an alert in the background/}]);
+        await extension.startup();
+        await extension.awaitFinish("alertCalled");
 
-  await extension.startup();
-  await extension.awaitFinish("alertCalled");
+        let chromeScript = loadChromeScript(async () => {
+          const {assert} = this;
+          assert.ok(!Services.wm.getEnumerator("alert:alert").hasMoreElements(), "Alerts should not be present after calling alert().");
+        });
+        chromeScript.destroy();
 
-  let chromeScript = loadChromeScript(async () => {
-    const {assert} = this;
-    assert.ok(!Services.wm.getEnumerator("alert:alert").hasMoreElements(),
-              "Alerts should not be present after calling alert().");
-  });
-  chromeScript.destroy();
+        await consoleMonitor.finished();
 
-  await consoleMonitor.finished();
+        await opened;
+        consoleOpened.destroy();
 
-  await opened;
-  consoleOpened.destroy();
+        chromeScript = loadChromeScript(async () => {
+          const {sendAsyncMessage} = this;
+          let {require} = ChromeUtils.import ("resource://devtools/shared/Loader.jsm");
+          require("devtools/client/framework/devtools-browser");
+          let {BrowserConsoleManager} = require("devtools/client/webconsole/browser-console-manager");
 
-  chromeScript = loadChromeScript(async () => {
-    const {sendAsyncMessage} = this;
-    let {require} = ChromeUtils.import("resource://devtools/shared/Loader.jsm");
-    require("devtools/client/framework/devtools-browser");
-    let {HUDService} = require("devtools/client/webconsole/hudservice");
+          // And then double check that we have an actual browser console.
+          let haveConsole = !!BrowserConsoleManager.getBrowserConsole();
 
-    // And then double check that we have an actual browser console.
-    let haveConsole = !!HUDService.getBrowserConsole();
+          if (haveConsole) {
+            await BrowserConsoleManager.toggleBrowserConsole();
+          }
+          sendAsyncMessage("done", haveConsole);
+        });
 
-    if (haveConsole) {
-      await HUDService.toggleBrowserConsole();
-    }
-    sendAsyncMessage("done", haveConsole);
-  });
+        let consoleShown = await chromeScript.promiseOneMessage("done");
+        ok(consoleShown, "console was shown");
+        chromeScript.destroy();
 
-  let consoleShown = await chromeScript.promiseOneMessage("done");
-  ok(consoleShown, "console was shown");
-  chromeScript.destroy();
+        await extension.unload();
+      });
+    </script>
 
-  await extension.unload();
-});
-</script>
-
-</body>
+  </body>
 </html>
diff --git a/toolkit/components/extensions/test/mochitest/test_ext_webnavigation.html b/toolkit/components/extensions/test/mochitest/test_ext_webnavigation.html
index 27fce6ba7d..f471ef6a2f 100644
--- a/toolkit/components/extensions/test/mochitest/test_ext_webnavigation.html
+++ b/toolkit/components/extensions/test/mochitest/test_ext_webnavigation.html
@@ -74,6 +74,7 @@ function backgroundScript() {
 
 const BASE = "http://mochi.test:8888/tests/toolkit/components/extensions/test/mochitest";
 const URL = BASE + "/file_WebNavigation_page1.html";
+const FORM_URL = URL + "?";
 const FRAME = BASE + "/file_WebNavigation_page2.html";
 const FRAME2 = BASE + "/file_WebNavigation_page3.html";
 const FRAME_PUSHSTATE = BASE + "/file_WebNavigation_page3_pushState.html";
@@ -187,11 +188,11 @@ add_task(async function webnav_transitions_props() {
 
   // transitionType: form_submit
   received = [];
-  await loadAndWait(win, "onCompleted", URL, () => {
+  await loadAndWait(win, "onCompleted", FORM_URL, () => {
     win.document.querySelector("form").submit();
   });
 
-  found = received.find((data) => (data.event == "onCommitted" && data.url == URL));
+  found = received.find((data) => (data.event == "onCommitted" && data.url == FORM_URL));
 
   ok(found, "Got the onCommitted event");
 
@@ -220,9 +221,9 @@ add_task(async function webnav_transitions_props() {
 
   // transitionQualifier: forward_back
   received = [];
-  await loadAndWait(win, "onCompleted", URL, () => { win.history.back(); });
+  await loadAndWait(win, "onCompleted", FORM_URL, () => { win.history.back(); });
 
-  found = received.find((data) => (data.event == "onCommitted" && data.url == URL));
+  found = received.find((data) => (data.event == "onCommitted" && data.url == FORM_URL));
 
   ok(found, "Got the onCommitted event");
 
diff --git a/toolkit/components/extensions/test/xpcshell/test_ext_adoption_with_private_field_xrays.js b/toolkit/components/extensions/test/xpcshell/test_ext_adoption_with_private_field_xrays.js
new file mode 100644
index 0000000000..bc4e0409cb
--- /dev/null
+++ b/toolkit/components/extensions/test/xpcshell/test_ext_adoption_with_private_field_xrays.js
@@ -0,0 +1,160 @@
+"use strict";
+
+// ExtensionContent.jsm needs to know when it's running from xpcshell,
+// to use the right timeout for content scripts executed at document_idle.
+ExtensionTestUtils.mockAppInfo();
+const server = createHttpServer();
+server.registerDirectory("/data/", do_get_file("data"));
+
+const BASE_URL = `http://localhost:${server.identity.primaryPort}/data`;
+
+add_task(async function test_contentscript_private_field_xrays() {
+  async function contentScript() {
+    let node = window.document.createElement("div");
+
+    class Base {
+      constructor(o) {
+        return o;
+      }
+    }
+
+    class A extends Base {
+      #x = 5;
+      static gx(o) {
+        return o.#x;
+      }
+      static sx(o, v) {
+        o.#x = v;
+      }
+    }
+
+    browser.test.log(A.toString());
+
+    // Stamp node with A's private field.
+    new A(node);
+
+    browser.test.log("stamped");
+
+    browser.test.assertEq(
+      A.gx(node),
+      5,
+      "We should be able to see our expando private field"
+    );
+    browser.test.log("Read");
+    browser.test.assertThrows(
+      () => A.gx(node.wrappedJSObject),
+      /Trying to read undeclared field/,
+      "Underlying object should not have our private field"
+    );
+
+    browser.test.log("threw");
+    window.frames[0].document.adoptNode(node);
+    browser.test.log("adopted");
+    browser.test.assertEq(
+      A.gx(node),
+      5,
+      "Adoption should not change expando private field"
+    );
+    browser.test.log("read");
+    browser.test.assertThrows(
+      () => A.gx(node.wrappedJSObject),
+      /Trying to read undeclared field/,
+      "Adoption should really not change expandos private fields"
+    );
+    browser.test.log("threw2");
+
+    // Repeat but now with an object that has a reference from the
+    // window it's being cloned into.
+    node = window.document.createElement("div");
+    // Stamp node with A's private field.
+    new A(node);
+    A.sx(node, 6);
+
+    browser.test.assertEq(
+      A.gx(node),
+      6,
+      "We should be able to see our expando (2)"
+    );
+    browser.test.assertThrows(
+      () => A.gx(node.wrappedJSObject),
+      /Trying to read undeclared field/,
+      "Underlying object should not have exxpando. (2)"
+    );
+
+    window.frames[0].wrappedJSObject.incoming = node.wrappedJSObject;
+    window.frames[0].document.adoptNode(node);
+
+    browser.test.assertEq(
+      A.gx(node),
+      6,
+      "We should be able to see our expando (3)"
+    );
+    browser.test.assertThrows(
+      () => A.gx(node.wrappedJSObject),
+      /Trying to read undeclared field/,
+      "Underlying object should not have exxpando. (3)"
+    );
+
+    // Repeat once more, now with an expando that refers to the object itself
+    node = window.document.createElement("div");
+    new A(node);
+    A.sx(node, node);
+
+    browser.test.assertEq(
+      A.gx(node),
+      node,
+      "We should be able to see our self-referential expando (4)"
+    );
+    browser.test.assertThrows(
+      () => A.gx(node.wrappedJSObject),
+      /Trying to read undeclared field/,
+      "Underlying object should not have exxpando. (4)"
+    );
+
+    window.frames[0].document.adoptNode(node);
+
+    browser.test.assertEq(
+      A.gx(node),
+      node,
+      "Adoption should not change our self-referential expando (4)"
+    );
+    browser.test.assertThrows(
+      () => A.gx(node.wrappedJSObject),
+      /Trying to read undeclared field/,
+      "Adoption should not change underlying object. (4)"
+    );
+
+    // And test what happens if we now set document.domain and cause
+    // wrapper remapping.
+    let doc = window.frames[0].document;
+    // eslint-disable-next-line no-self-assign
+    doc.domain = doc.domain;
+
+    browser.test.notifyPass("privateFieldXRayAdoption");
+  }
+
+  let extension = ExtensionTestUtils.loadExtension({
+    manifest: {
+      content_scripts: [
+        {
+          matches: ["http://*/*/file_toplevel.html"],
+          js: ["content_script.js"],
+        },
+      ],
+    },
+
+    files: {
+      "content_script.js": contentScript,
+    },
+  });
+
+  await extension.startup();
+  let contentPage = await ExtensionTestUtils.loadContentPage(
+    `${BASE_URL}/file_toplevel.html`
+  );
+
+  await extension.awaitFinish("privateFieldXRayAdoption");
+
+  await contentPage.close();
+  await extension.unload();
+});
diff --git a/toolkit/components/extensions/test/xpcshell/test_ext_geckoProfiler_control.js b/toolkit/components/extensions/test/xpcshell/test_ext_geckoProfiler_control.js
index 37c37ee2da..a92855d0de 100644
--- a/toolkit/components/extensions/test/xpcshell/test_ext_geckoProfiler_control.js
+++ b/toolkit/components/extensions/test/xpcshell/test_ext_geckoProfiler_control.js
@@ -1,5 +1,8 @@
 "use strict";
 
+const {OS} = ChromeUtils.import("resource://gre/modules/osfile.jsm");
+
+
 let getExtension = () => {
   return ExtensionTestUtils.loadExtension({
     background: async function() {
@@ -11,7 +14,7 @@ let getExtension = () => {
         }
       };
 
-      browser.test.onMessage.addListener(async message => {
+      browser.test.onMessage.addListener(async (message, data) => {
         let result;
         switch (message) {
           case "start":
@@ -58,6 +61,16 @@ let getExtension = () => {
             );
             browser.test.sendMessage("tested profile");
             break;
+          case "test dump to file":
+            try {
+              await browser.geckoProfiler.dumpProfileToFile(data.fileName);
+              browser.test.sendMessage("tested dump to file", {});
+            } catch (e) {
+              browser.test.sendMessage("tested dump to file", {
+                error: e.message,
+              });
+            }
+            break;
           case "test profile as array buffer":
             let arrayBuffer = await browser.geckoProfiler.getProfileAsArrayBuffer();
             browser.test.assertTrue(
@@ -107,6 +120,16 @@ let getExtension = () => {
   });
 };
 
+let verifyProfileData = bytes => {
+  let textDecoder = new TextDecoder();
+  let profile = JSON.parse(textDecoder.decode(bytes));
+  ok("libs" in profile, "The profile contains libs.");
+  ok("meta" in profile, "The profile contains meta.");
+  ok("threads" in profile, "The profile contains threads.");
+  ok(profile.threads.some(t => t.name == "GeckoMain"),
+     "The profile contains a GeckoMain thread.");
+};
+
 add_task(async function testProfilerControl() {
   const acceptedExtensionIdsPref =
     "extensions.geckoProfiler.acceptedExtensionIds";
@@ -126,6 +149,41 @@ add_task(async function testProfilerControl() {
   extension.sendMessage("test profile");
   await extension.awaitMessage("tested profile");
 
+  const profilerPath = OS.Path.join(OS.Constants.Path.profileDir, "profiler");
+  let data, fileName, targetPath;
+
+  // test with file name only
+  fileName = "bar.profile";
+  targetPath = OS.Path.join(profilerPath, fileName);
+  extension.sendMessage("test dump to file", {fileName});
+  data = await extension.awaitMessage("tested dump to file");
+  equal(data.error, undefined, "No error thrown");
+  ok(await OS.File.exists(targetPath), "Saved gecko profile exists.");
+  verifyProfileData(await OS.File.read(targetPath));
+
+  // test overwriting the formerly created file
+  extension.sendMessage("test dump to file", {fileName});
+  data = await extension.awaitMessage("tested dump to file");
+  equal(data.error, undefined, "No error thrown");
+  ok(await OS.File.exists(targetPath), "Saved gecko profile exists.");
+  verifyProfileData(await OS.File.read(targetPath));
+
+  // test with a POSIX path, which is not allowed
+  fileName = "foo/bar.profile";
+  targetPath = OS.Path.join(profilerPath, ...fileName.split("/"));
+  extension.sendMessage("test dump to file", {fileName});
+  data = await extension.awaitMessage("tested dump to file");
+  equal(data.error, "Path cannot contain a subdirectory.");
+  ok(!await OS.File.exists(targetPath), "Gecko profile hasn't been saved.");
+
+  // test with a non POSIX path which is not allowed
+  fileName = "foo\\bar.profile";
+  targetPath = OS.Path.join(profilerPath, ...fileName.split("\\"));
+  extension.sendMessage("test dump to file", {fileName});
+  data = await extension.awaitMessage("tested dump to file");
+  equal(data.error, "Path cannot contain a subdirectory.");
+  ok(!await OS.File.exists(targetPath), "Gecko profile hasn't been saved.");
+
   extension.sendMessage("test profile as array buffer");
   await extension.awaitMessage("tested profile as array buffer");
 
diff --git a/toolkit/components/extensions/test/xpcshell/test_ext_geckoProfiler_schema.js b/toolkit/components/extensions/test/xpcshell/test_ext_geckoProfiler_schema.js
index c9734c41dc..d0bbf7e60f 100644
--- a/toolkit/components/extensions/test/xpcshell/test_ext_geckoProfiler_schema.js
+++ b/toolkit/components/extensions/test/xpcshell/test_ext_geckoProfiler_schema.js
@@ -31,7 +31,7 @@ add_task(async function() {
 
   Services.prefs.clearUserPref(acceptedExtensionIdsPref);
 
-  const allFeaturesAcceptedByProfiler = Services.profiler.GetAllFeatures([]);
+  const allFeaturesAcceptedByProfiler = Services.profiler.GetAllFeatures();
   ok(
     allFeaturesAcceptedByProfiler.length >= 2,
     "Either we've massively reduced the profiler's feature set, or something is wrong."
@@ -47,7 +47,9 @@ add_task(async function() {
   }
   for (const feature of acceptedFeatures) {
     ok(
-      allFeaturesAcceptedByProfiler.includes(feature),
+      // Bug 1594566 - ignore Responsiveness until the extension is updated
+      allFeaturesAcceptedByProfiler.includes(feature) ||
+        feature == "responsiveness",
       `The schema of the geckoProfiler.start() method mentions a "${feature}" feature which is not supported by the profiler.`
     );
   }
diff --git a/toolkit/components/extensions/test/xpcshell/test_ext_schemas_interactive.js b/toolkit/components/extensions/test/xpcshell/test_ext_schemas_interactive.js
index 961cb3a23d..66de5c8aba 100644
--- a/toolkit/components/extensions/test/xpcshell/test_ext_schemas_interactive.js
+++ b/toolkit/components/extensions/test/xpcshell/test_ext_schemas_interactive.js
@@ -57,7 +57,6 @@ let experimentFiles = {
     };
   },
 
-  /* globals ExtensionAPI */
   "child.js": () => {
     this.userinputtest = class extends ExtensionAPI {
       getAPI(context) {
diff --git a/toolkit/components/extensions/test/xpcshell/test_ext_storage_sync.js b/toolkit/components/extensions/test/xpcshell/test_ext_storage_sync.js
index 8be8c82812..35cf46dbdf 100644
--- a/toolkit/components/extensions/test/xpcshell/test_ext_storage_sync.js
+++ b/toolkit/components/extensions/test/xpcshell/test_ext_storage_sync.js
@@ -22,9 +22,6 @@ const { BulkKeyBundle } = ChromeUtils.import(
 );
 const { Utils } = ChromeUtils.import("resource://services-sync/util.js");
 
-/* globals BulkKeyBundle, CommonUtils, EncryptionRemoteTransformer */
-/* globals Utils */
-
 function handleCannedResponse(cannedResponse, request, response) {
   response.setStatusLine(
     null,
diff --git a/toolkit/components/extensions/test/xpcshell/xpcshell-common.ini b/toolkit/components/extensions/test/xpcshell/xpcshell-common.ini
index 37314198d4..dc711e1d9e 100644
--- a/toolkit/components/extensions/test/xpcshell/xpcshell-common.ini
+++ b/toolkit/components/extensions/test/xpcshell/xpcshell-common.ini
@@ -23,7 +23,7 @@ skip-if = os == "android"
 skip-if = appname == "thunderbird" || os == "android"
 [test_ext_captivePortal.js]
 # As with test_captive_portal_service.js, we use the same limits here.
-skip-if = os == "android" # CP service is disabled on Android
+skip-if = os == "android" || (os == "mac" && debug) # CP service is disabled on Android, macosx1014/debug due to 1564534
 run-sequentially = node server exceptions dont replay well
 [test_ext_cookieBehaviors.js]
 [test_ext_cookies_samesite.js]
diff --git a/toolkit/components/extensions/test/xpcshell/xpcshell-content.ini b/toolkit/components/extensions/test/xpcshell/xpcshell-content.ini
index bfee483bda..e03f6c7791 100644
--- a/toolkit/components/extensions/test/xpcshell/xpcshell-content.ini
+++ b/toolkit/components/extensions/test/xpcshell/xpcshell-content.ini
@@ -11,4 +11,6 @@ skip-if = (os == "android" && debug) || (os == "win" && debug) # Windows: Bug 14
 [test_ext_contentScripts_register.js]
 [test_ext_contexts_gc.js]
 [test_ext_adoption_with_xrays.js]
+[test_ext_adoption_with_private_field_xrays.js]
+skip-if = !nightly_build
 [test_ext_shadowdom.js]
diff --git a/toolkit/components/finalizationwitness/FinalizationWitnessService.cpp b/toolkit/components/finalizationwitness/FinalizationWitnessService.cpp
index 86c0b9ae7b..0db4301bd1 100644
--- a/toolkit/components/finalizationwitness/FinalizationWitnessService.cpp
+++ b/toolkit/components/finalizationwitness/FinalizationWitnessService.cpp
@@ -7,6 +7,7 @@
 #include "nsString.h"
 #include "jsapi.h"
 #include "js/CallNonGenericMethod.h"
+#include "js/Object.h"  // JS::GetClass, JS::GetReservedSlot
 #include "js/PropertySpec.h"
 #include "mozJSComponentLoader.h"
 #include "nsZipArchive.h"
@@ -73,7 +74,7 @@ enum { WITNESS_SLOT_EVENT, WITNESS_INSTANCES_SLOTS };
  */
 already_AddRefed<FinalizationEvent> ExtractFinalizationEvent(
     JSObject* objSelf) {
-  JS::Value slotEvent = JS_GetReservedSlot(objSelf, WITNESS_SLOT_EVENT);
+  JS::Value slotEvent = JS::GetReservedSlot(objSelf, WITNESS_SLOT_EVENT);
   if (slotEvent.isUndefined()) {
     // Forget() has been called
     return nullptr;
@@ -124,7 +125,7 @@ static const JSClass sWitnessClass = {
     &sWitnessClassOps};
 
 bool IsWitness(JS::Handle<JS::Value> v) {
-  return v.isObject() && JS_GetClass(&v.toObject()) == &sWitnessClass;
+  return v.isObject() && JS::GetClass(&v.toObject()) == &sWitnessClass;
 }
 
 /**
diff --git a/toolkit/components/mozintl/components.conf b/toolkit/components/mozintl/components.conf
index ce80b692cc..9339f8ee4a 100644
--- a/toolkit/components/mozintl/components.conf
+++ b/toolkit/components/mozintl/components.conf
@@ -11,8 +11,10 @@ Classes = [
     },
 
     {
+        'js_name': 'intl',
         'cid': '{35ec195a-e8d0-4300-83af-c8a2cc84b4a3}',
         'contract_ids': ['@mozilla.org/mozintl;1'],
+        'interfaces': ['mozIMozIntl'],
         'jsm': 'resource://gre/modules/mozIntl.jsm',
         'constructor': 'MozIntl',
     },
diff --git a/toolkit/components/osfile/NativeOSFileInternals.cpp b/toolkit/components/osfile/NativeOSFileInternals.cpp
index 13436a77d5..deb0db9a27 100644
--- a/toolkit/components/osfile/NativeOSFileInternals.cpp
+++ b/toolkit/components/osfile/NativeOSFileInternals.cpp
@@ -35,6 +35,7 @@
 #include "jsfriendapi.h"
 #include "js/ArrayBuffer.h"  // JS::GetArrayBufferByteLength,IsArrayBufferObject,NewArrayBufferWithContents,StealArrayBufferContents
 #include "js/Conversions.h"
+#include "js/experimental/TypedData.h"  // JS_NewUint8ArrayWithBuffer
 #include "js/MemoryFunctions.h"
 #include "js/UniquePtr.h"
 #include "js/Utility.h"
diff --git a/toolkit/components/osfile/modules/osfile_win_back.jsm b/toolkit/components/osfile/modules/osfile_win_back.jsm
index ba44e8a50c..1b441c1ac3 100644
--- a/toolkit/components/osfile/modules/osfile_win_back.jsm
+++ b/toolkit/components/osfile/modules/osfile_win_back.jsm
@@ -20,7 +20,6 @@
  */
 
 /* eslint-env mozilla/chrome-worker, node */
-/* global OS */
 
 // eslint-disable-next-line no-lone-blocks
 {
diff --git a/toolkit/components/passwordmgr/LoginImport.jsm b/toolkit/components/passwordmgr/LoginImport.jsm
index c3d839aa07..b1752b9dff 100644
--- a/toolkit/components/passwordmgr/LoginImport.jsm
+++ b/toolkit/components/passwordmgr/LoginImport.jsm
@@ -1,5 +1,3 @@
-/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
-/* vim: set ts=2 et sw=2 tw=80 filetype=javascript: */
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
diff --git a/toolkit/components/passwordmgr/components.conf b/toolkit/components/passwordmgr/components.conf
index 8a442eb161..20d1d26d4e 100644
--- a/toolkit/components/passwordmgr/components.conf
+++ b/toolkit/components/passwordmgr/components.conf
@@ -4,8 +4,10 @@
 
 Classes = [
     {
+        'js_name': 'logins',
         'cid': '{cb9e0de8-3598-4ed7-857b-827f011ad5d8}',
         'contract_ids': ['@mozilla.org/login-manager;1'],
+        'interfaces': ['nsILoginManager'],
         'jsm': 'resource://gre/modules/LoginManager.jsm',
         'constructor': 'LoginManager',
     },
diff --git a/toolkit/components/passwordmgr/storage-mozStorage.js b/toolkit/components/passwordmgr/storage-mozStorage.js
index 7d8bf0d3d1..93b3441bb2 100644
--- a/toolkit/components/passwordmgr/storage-mozStorage.js
+++ b/toolkit/components/passwordmgr/storage-mozStorage.js
@@ -634,8 +634,6 @@ LoginManagerStorage_mozStorage.prototype = {
       let params = { guid: aLogin.guid, timeDeleted: Date.now() };
       let stmt = this._dbCreateStatement(query, params);
       stmt.execute();
-    } catch (ex) {
-      throw ex;
     } finally {
       if (stmt) {
         stmt.reset();
diff --git a/toolkit/components/passwordmgr/test/browser/head.js b/toolkit/components/passwordmgr/test/browser/head.js
index 73c8c5c4e1..17c6f19bc7 100644
--- a/toolkit/components/passwordmgr/test/browser/head.js
+++ b/toolkit/components/passwordmgr/test/browser/head.js
@@ -262,24 +262,22 @@ function openPasswordManager(openingFunc, waitForFilter) {
 
 // Autocomplete popup related functions //
 
-function openACPopup(popup, browser, inputSelector) {
-  return new Promise(async resolve => {
-    let promiseShown = BrowserTestUtils.waitForEvent(popup, "popupshown");
+async function openACPopup(popup, browser, inputSelector) {
+  let promiseShown = BrowserTestUtils.waitForEvent(popup, "popupshown");
 
-    await SimpleTest.promiseFocus(browser);
-    info("content window focused");
+  await SimpleTest.promiseFocus(browser);
+  info("content window focused");
 
-    // Focus the username field to open the popup.
-    await ContentTask.spawn(browser, [inputSelector], function openAutocomplete(
-      sel
-    ) {
-      content.document.querySelector(sel).focus();
-    });
-
-    let shown = await promiseShown;
-    ok(shown, "autocomplete popup shown");
-    resolve(shown);
+  // Focus the username field to open the popup.
+  await ContentTask.spawn(browser, [inputSelector], function openAutocomplete(
+    sel
+  ) {
+    content.document.querySelector(sel).focus();
   });
+
+  let shown = await promiseShown;
+  ok(shown, "autocomplete popup shown");
+  return shown;
 }
 
 // Contextmenu functions //
diff --git a/toolkit/components/places/UnifiedComplete.jsm b/toolkit/components/places/UnifiedComplete.jsm
index b4336422bf..66d2c29aff 100644
--- a/toolkit/components/places/UnifiedComplete.jsm
+++ b/toolkit/components/places/UnifiedComplete.jsm
@@ -2726,20 +2726,14 @@ UnifiedComplete.prototype = {
       this._promiseDatabase = (async () => {
         let conn = await PlacesUtils.promiseLargeCacheDBConnection();
 
-        try {
-          Sqlite.shutdown.addBlocker(
-            "Places UnifiedComplete.js closing",
-            () => {
-              // Break a possible cycle through the
-              // previous result, the controller and
-              // ourselves.
-              this._currentSearch = null;
-            }
-          );
-        } catch (ex) {
-          // It's too late to block shutdown.
-          throw ex;
-        }
+        // We don't catch exceptions here as it is too late to block shutdown.
+        Sqlite.shutdown.addBlocker("Places UnifiedComplete.js closing", () => {
+          // Break a possible cycle through the
+          // previous result, the controller and
+          // ourselves.
+          this._currentSearch = null;
+        });
+
         await UrlbarProviderOpenTabs.promiseDb();
         return conn;
       })().catch(ex => {
diff --git a/toolkit/components/prompts/src/components.conf b/toolkit/components/prompts/src/components.conf
index a26b600b29..1c663311de 100644
--- a/toolkit/components/prompts/src/components.conf
+++ b/toolkit/components/prompts/src/components.conf
@@ -16,8 +16,10 @@ Classes = [
         'constructor': 'AuthPromptAdapterFactory',
     },
     {
+        'js_name': 'prompt',
         'cid': '{7ad1b327-6dfa-46ec-9234-f2a620ea7e00}',
         'contract_ids': ['@mozilla.org/embedcomp/prompt-service;1'],
+        'interfaces': ['nsIPromptService'],
         'jsm': 'resource://gre/modules/Prompter.jsm',
         'constructor': 'EmbedPrompter',
     },
diff --git a/toolkit/components/search/components.conf b/toolkit/components/search/components.conf
index 01090a30c7..da1c172063 100644
--- a/toolkit/components/search/components.conf
+++ b/toolkit/components/search/components.conf
@@ -6,8 +6,10 @@ HAVE_SIDEBAR = buildconfig.substs['MOZ_BUILD_APP'] in ('browser', 'mobile/androi
 
 Classes = [
     {
+        'js_name': 'search',
         'cid': '{7319788a-fe93-4db3-9f39-818cf08f4256}',
         'contract_ids': ['@mozilla.org/browser/search-service;1'],
+        'interfaces': ['nsISearchService'],
         'jsm': 'resource://gre/modules/SearchService.jsm',
         'constructor': 'SearchService',
         'processes': ProcessSelector.MAIN_PROCESS_ONLY,
diff --git a/toolkit/components/search/tests/xpcshell/head_search.js b/toolkit/components/search/tests/xpcshell/head_search.js
index f43df0af69..8d1814f3a3 100644
--- a/toolkit/components/search/tests/xpcshell/head_search.js
+++ b/toolkit/components/search/tests/xpcshell/head_search.js
@@ -383,8 +383,6 @@ async function withGeoServer(
 
   try {
     await testFn(gRequests);
-  } catch (ex) {
-    throw ex;
   } finally {
     srv.stop(() => {});
     defaultBranch.setCharPref(PREF_SEARCH_URL, originalURL);
diff --git a/toolkit/components/startup/nsAppStartup.cpp b/toolkit/components/startup/nsAppStartup.cpp
index 50056de158..374abc98bd 100644
--- a/toolkit/components/startup/nsAppStartup.cpp
+++ b/toolkit/components/startup/nsAppStartup.cpp
@@ -48,7 +48,7 @@
 #  include <mach/mach_time.h>
 #endif
 
-//#include "mozilla/IOInterposer.h"
+#include "mozilla/IOInterposer.h"
 #include "mozilla/Telemetry.h"
 #include "mozilla/StartupTimeline.h"
 
@@ -591,11 +591,11 @@ nsAppStartup::Observe(nsISupports* aSubject, const char* aTopic,
     ExitLastWindowClosingSurvivalArea();
   } else if (!strcmp(aTopic, "sessionstore-windows-restored")) {
     StartupTimeline::Record(StartupTimeline::SESSION_RESTORED);
-    //IOInterposer::EnteringNextStage();
+    IOInterposer::EnteringNextStage();
   } else if (!strcmp(aTopic, "sessionstore-init-started")) {
     StartupTimeline::Record(StartupTimeline::SESSION_RESTORE_INIT);
   } else if (!strcmp(aTopic, "xpcom-shutdown")) {
-    //IOInterposer::EnteringNextStage();
+    IOInterposer::EnteringNextStage();
   } else if (!strcmp(aTopic, "quit-application")) {
     StartupTimeline::Record(StartupTimeline::QUIT_APPLICATION);
   } else if (!strcmp(aTopic, "profile-before-change")) {
diff --git a/toolkit/components/telemetry/Histograms.json b/toolkit/components/telemetry/Histograms.json
index 901f8f7b60..37e636202f 100644
--- a/toolkit/components/telemetry/Histograms.json
+++ b/toolkit/components/telemetry/Histograms.json
@@ -625,15 +625,6 @@
     "bug_numbers": [1545093],
     "description": "Time from the beginning of the first slice to the end of the last slice (ms)"
   },
-  "GC_BUDGET_MS": {
-    "record_in_processes": ["main", "content"],
-    "alert_emails": ["dev-telemetry-gc-alerts@mozilla.org"],
-    "expires_in_version": "never",
-    "kind": "linear",
-    "high": 100,
-    "n_buckets": 10,
-    "description": "Requested GC slice budget (ms)"
-  },
   "GC_ANIMATION_MS": {
     "record_in_processes": ["main", "content"],
     "alert_emails": ["dev-telemetry-gc-alerts@mozilla.org", "jcoppeard@mozilla.com", "sdetar@mozilla.com"],
@@ -683,24 +674,6 @@
     "n_buckets": 50,
     "description": "Time spent running JS GC compact phase (ms)"
   },
-  "GC_MARK_ROOTS_MS": {
-    "record_in_processes": ["main", "content"],
-    "alert_emails": ["dev-telemetry-gc-alerts@mozilla.org"],
-    "expires_in_version": "never",
-    "kind": "linear",
-    "high": 200,
-    "n_buckets": 50,
-    "description": "Time spent marking GC roots (ms)"
-  },
-  "GC_MARK_GRAY_MS": {
-    "record_in_processes": ["main", "content"],
-    "alert_emails": ["dev-telemetry-gc-alerts@mozilla.org"],
-    "expires_in_version": "never",
-    "kind": "linear",
-    "high": 200,
-    "n_buckets": 50,
-    "description": "Time spent marking gray GC objects (ms)"
-  },
   "GC_SLICE_MS": {
     "record_in_processes": ["main", "content"],
     "alert_emails": ["dev-telemetry-gc-alerts@mozilla.org"],
@@ -804,15 +777,6 @@
     "bug_numbers": [1528867],
     "description": "Size of the GC nursery (bytes)"
   },
-  "GC_PRETENURE_COUNT": {
-    "record_in_processes": ["main", "content"],
-    "alert_emails": ["dev-telemetry-gc-alerts@mozilla.org"],
-    "expires_in_version": "never",
-    "kind": "enumerated",
-    "n_values": 32,
-    "bug_numbers": [1293262],
-    "description": "How many objects groups were selected for pretenuring by a minor GC"
-  },
   "GC_SLICE_DURING_IDLE": {
     "record_in_processes": ["main", "content"],
     "alert_emails": ["dev-telemetry-gc-alerts@mozilla.org"],
@@ -843,17 +807,6 @@
     "bug_numbers": [1485299],
     "description": "The percentage of nursery objects that were promoted to tenured heap."
   },
-  "GC_MARK_RATE": {
-    "record_in_processes": ["main", "content"],
-    "alert_emails": ["dev-telemetry-gc-alerts@mozilla.org", "jcoppeard@mozilla.com"],
-    "expires_in_version": "never",
-    "kind": "linear",
-    "low": 1000,
-    "high": 1000000,
-    "n_buckets": 100,
-    "bug_numbers": [1475896],
-    "description": "The number of objects marked per ms during GC."
-  },
   "GEOLOCATION_ACCURACY_EXPONENTIAL": {
     "record_in_processes": ["main", "content"],
     "expires_in_version": "never",
@@ -959,28 +912,6 @@
     "n_values":  10,
     "description": "Count how often we use different fallbacks when the GPU process crashes: None=0, GPUProcessDecodingDisabled=1, GPUProcessDisabled=2"
   },
-  "JS_PRIVILEGED_PARSER_COMPILE_LAZY_AFTER_MS": {
-    "record_in_processes": ["main", "content"],
-    "alert_emails": ["dteller@mozilla.com"],
-    "expires_in_version": "70",
-    "bug_numbers": [1343483],
-    "kind": "exponential",
-    "low": 10,
-    "high": 10000,
-    "n_buckets": 10,
-    "description": "Time elapsed between the moment a function is lazy-parsed (end of parsing of the ScriptSource) and the moment it is recompiled as non-lazy (start of compilation), in milliseconds, for privileged code."
-  },
-  "JS_WEB_PARSER_COMPILE_LAZY_AFTER_MS": {
-    "record_in_processes": ["main", "content"],
-    "alert_emails": ["dteller@mozilla.com"],
-    "expires_in_version": "70",
-    "bug_numbers": [1343483],
-    "kind": "exponential",
-    "low": 10,
-    "high": 10000,
-    "n_buckets": 10,
-    "description": "Time elapsed between the moment a function is lazy-parsed (end of parsing of the ScriptSource) and the moment it is recompiled as non-lazy (start of compilation), in milliseconds, for web code."
-  },
   "XUL_CACHE_DISABLED": {
     "record_in_processes": ["main", "content"],
     "expires_in_version": "default",
diff --git a/toolkit/components/telemetry/build_scripts/gen_histogram_enum.py b/toolkit/components/telemetry/build_scripts/gen_histogram_enum.py
index 17e4b46dde..572e38696d 100644
--- a/toolkit/components/telemetry/build_scripts/gen_histogram_enum.py
+++ b/toolkit/components/telemetry/build_scripts/gen_histogram_enum.py
@@ -29,6 +29,7 @@ header = """
 #define mozilla_TelemetryHistogramEnums_h
 
 #include "mozilla/TemplateLib.h"
+#include "mozilla/TypeTraits.h"
 
 namespace mozilla {
 namespace Telemetry {
diff --git a/toolkit/components/telemetry/core/Telemetry.cpp b/toolkit/components/telemetry/core/Telemetry.cpp
index de4811f0fd..71c718d244 100644
--- a/toolkit/components/telemetry/core/Telemetry.cpp
+++ b/toolkit/components/telemetry/core/Telemetry.cpp
@@ -80,7 +80,6 @@
 #include "nsXULAppAPI.h"
 #include "other/CombinedStacks.h"
 //#include "other/TelemetryIOInterposeObserver.h"
-#include "other/WebrtcTelemetry.h"
 #include "plstr.h"
 #if defined(MOZ_GECKO_PROFILER)
 #  include "shared-libraries.h"
@@ -200,8 +199,6 @@ class TelemetryImpl final : public nsITelemetry, public nsIMemoryReporter {
   uint32_t mFailedLockCount;
   nsCOMArray<nsIFetchTelemetryDataCallback> mCallbacks;
   friend class nsFetchTelemetryData;
-
-  WebrtcTelemetry mWebrtcTelemetry;
 };
 
 TelemetryImpl* TelemetryImpl::sTelemetry = nullptr;
@@ -224,10 +221,6 @@ TelemetryImpl::CollectReports(nsIHandleReportCallback* aHandleReport,
       TelemetryScalar::GetMapShallowSizesOfExcludingThis(aMallocSizeOf),
       "Memory used by the Telemetry Scalar implemenation");
 
-  COLLECT_REPORT("explicit/telemetry/WebRTC",
-                 mWebrtcTelemetry.SizeOfExcludingThis(aMallocSizeOf),
-                 "Memory used by WebRTC Telemetry");
-
   {  // Scope for mHashMutex lock
     MutexAutoLock lock(mHashMutex);
     COLLECT_REPORT("explicit/telemetry/PrivateSQL",
@@ -673,12 +666,6 @@ TelemetryImpl::GetDebugSlowSQL(JSContext* cx,
   return NS_ERROR_FAILURE;
 }
 
-NS_IMETHODIMP
-TelemetryImpl::GetWebrtcStats(JSContext* cx, JS::MutableHandle<JS::Value> ret) {
-  if (mWebrtcTelemetry.GetWebrtcStats(cx, ret)) return NS_OK;
-  return NS_ERROR_FAILURE;
-}
-
 NS_IMETHODIMP
 TelemetryImpl::GetMaximalNumberOfConcurrentThreads(uint32_t* ret) {
   *ret = nsThreadManager::get().GetHighestNumberOfThreads();
@@ -1487,14 +1474,6 @@ void TelemetryImpl::RecordSlowStatement(const nsACString& sql,
   StoreSlowSQL(fullSQL, delay, Unsanitized);
 }
 
-void TelemetryImpl::RecordIceCandidates(const uint32_t iceCandidateBitmask,
-                                        const bool success) {
-  if (!sTelemetry || !TelemetryHistogram::CanRecordExtended()) return;
-
-  sTelemetry->mWebrtcTelemetry.RecordIceCandidateMask(iceCandidateBitmask,
-                                                      success);
-}
-
 #if defined(MOZ_GECKO_PROFILER)
 
 void TelemetryImpl::DoStackCapture(const nsACString& aKey) {
@@ -2002,11 +1981,6 @@ void RecordSlowSQLStatement(const nsACString& statement,
   TelemetryImpl::RecordSlowStatement(statement, dbName, delay);
 }
 
-void RecordWebrtcIceCandidates(const uint32_t iceCandidateBitmask,
-                               const bool success) {
-  TelemetryImpl::RecordIceCandidates(iceCandidateBitmask, success);
-}
-
 void Init() {
   // Make the service manager hold a long-lived reference to the service
   nsCOMPtr<nsITelemetry> telemetryService =
diff --git a/toolkit/components/telemetry/core/Telemetry.h b/toolkit/components/telemetry/core/Telemetry.h
index 10abe72654..60866f21ef 100644
--- a/toolkit/components/telemetry/core/Telemetry.h
+++ b/toolkit/components/telemetry/core/Telemetry.h
@@ -420,15 +420,6 @@ bool CanRecordPrereleaseData();
 void RecordSlowSQLStatement(const nsACString& statement,
                             const nsACString& dbName, uint32_t delay);
 
-/**
- * Record Webrtc ICE candidate type combinations in a 17bit bitmask
- *
- * @param iceCandidateBitmask - the bitmask representing local and remote ICE
- *                              candidate types present for the connection
- * @param success - did the peer connection connected
- */
-void RecordWebrtcIceCandidates(const uint32_t iceCandidateBitmask,
-                               const bool success);
 /**
  * Initialize I/O Reporting
  * Initially this only records I/O for files in the binary directory.
diff --git a/toolkit/components/telemetry/core/TelemetryEvent.cpp b/toolkit/components/telemetry/core/TelemetryEvent.cpp
index 607820eb27..f223b3fbc1 100644
--- a/toolkit/components/telemetry/core/TelemetryEvent.cpp
+++ b/toolkit/components/telemetry/core/TelemetryEvent.cpp
@@ -10,7 +10,6 @@
 #include "jsapi.h"
 #include "js/Array.h"  // JS::GetArrayLength, JS::IsArrayObject, JS::NewArrayObject
 #include "mozilla/Maybe.h"
-#include "mozilla/Pair.h"
 #include "mozilla/Preferences.h"
 #include "mozilla/Services.h"
 #include "mozilla/StaticMutex.h"
@@ -1236,8 +1235,8 @@ nsresult TelemetryEvent::CreateSnapshots(uint32_t aDataset, bool aClear,
   // from JS recording Telemetry.
 
   // (1) Extract the events from storage with a lock held.
-  nsTArray<mozilla::Pair<const char*, EventRecordArray>> processEvents;
-  nsTArray<mozilla::Pair<uint32_t, EventRecordArray>> leftovers;
+  nsTArray<std::pair<const char*, EventRecordArray>> processEvents;
+  nsTArray<std::pair<uint32_t, EventRecordArray>> leftovers;
   {
     StaticMutexAutoLock locker(gTelemetryEventsMutex);
 
@@ -1273,10 +1272,10 @@ nsresult TelemetryEvent::CreateSnapshots(uint32_t aDataset, bool aClear,
         if (events.Length()) {
           const char* processName = GetNameForProcessID(ProcessID(iter.Key()));
           processEvents.AppendElement(
-              mozilla::MakePair(processName, std::move(events)));
+              std::make_pair(processName, std::move(events)));
           if (leftoverEvents.Length()) {
             leftovers.AppendElement(
-                mozilla::MakePair(iter.Key(), std::move(leftoverEvents)));
+                std::make_pair(iter.Key(), std::move(leftoverEvents)));
           }
         }
       }
@@ -1287,8 +1286,8 @@ nsresult TelemetryEvent::CreateSnapshots(uint32_t aDataset, bool aClear,
     if (aClear) {
       gEventRecords.Clear();
       for (auto pair : leftovers) {
-        gEventRecords.Put(pair.first(),
-                          new EventRecordArray(std::move(pair.second())));
+        gEventRecords.Put(pair.first,
+                          new EventRecordArray(std::move(pair.second)));
       }
       leftovers.Clear();
     }
@@ -1303,12 +1302,12 @@ nsresult TelemetryEvent::CreateSnapshots(uint32_t aDataset, bool aClear,
   const uint32_t processLength = processEvents.Length();
   for (uint32_t i = 0; i < processLength; ++i) {
     JS::RootedObject eventsArray(cx);
-    if (NS_FAILED(SerializeEventsArray(processEvents[i].second(), cx,
+    if (NS_FAILED(SerializeEventsArray(processEvents[i].second, cx,
                                        &eventsArray, aDataset))) {
       return NS_ERROR_FAILURE;
     }
 
-    if (!JS_DefineProperty(cx, rootObj, processEvents[i].first(), eventsArray,
+    if (!JS_DefineProperty(cx, rootObj, processEvents[i].first, eventsArray,
                            JSPROP_ENUMERATE)) {
       return NS_ERROR_FAILURE;
     }
diff --git a/toolkit/components/telemetry/core/TelemetryHistogram.cpp b/toolkit/components/telemetry/core/TelemetryHistogram.cpp
index b7f5c92cf9..8e0dda46df 100644
--- a/toolkit/components/telemetry/core/TelemetryHistogram.cpp
+++ b/toolkit/components/telemetry/core/TelemetryHistogram.cpp
@@ -11,6 +11,7 @@
 #include "jsfriendapi.h"
 #include "js/Array.h"  // JS::GetArrayLength, JS::IsArrayObject, JS::NewArrayObject
 #include "js/GCAPI.h"
+#include "js/Object.h"  // JS::GetClass, JS::GetPrivate, JS::SetPrivate
 #include "mozilla/dom/ToJSValue.h"
 #include "mozilla/gfx/GPUProcessManager.h"
 #include "mozilla/Atomics.h"
@@ -1788,13 +1789,13 @@ bool internal_JSHistogram_Add(JSContext* cx, unsigned argc, JS::Value* vp) {
   JS::CallArgs args = CallArgsFromVp(argc, vp);
 
   if (!args.thisv().isObject() ||
-      JS_GetClass(&args.thisv().toObject()) != &sJSHistogramClass) {
+      JS::GetClass(&args.thisv().toObject()) != &sJSHistogramClass) {
     JS_ReportErrorASCII(cx, "Wrong JS class, expected JSHistogram class");
     return false;
   }
 
   JSObject* obj = &args.thisv().toObject();
-  JSHistogramData* data = static_cast<JSHistogramData*>(JS_GetPrivate(obj));
+  JSHistogramData* data = static_cast<JSHistogramData*>(JS::GetPrivate(obj));
   MOZ_ASSERT(data);
   HistogramID id = data->histogramId;
   MOZ_ASSERT(internal_IsHistogramEnumId(id));
@@ -1824,13 +1825,13 @@ bool internal_JSHistogram_Name(JSContext* cx, unsigned argc, JS::Value* vp) {
   JS::CallArgs args = CallArgsFromVp(argc, vp);
 
   if (!args.thisv().isObject() ||
-      JS_GetClass(&args.thisv().toObject()) != &sJSHistogramClass) {
+      JS::GetClass(&args.thisv().toObject()) != &sJSHistogramClass) {
     JS_ReportErrorASCII(cx, "Wrong JS class, expected JSHistogram class");
     return false;
   }
 
   JSObject* obj = &args.thisv().toObject();
-  JSHistogramData* data = static_cast<JSHistogramData*>(JS_GetPrivate(obj));
+  JSHistogramData* data = static_cast<JSHistogramData*>(JS::GetPrivate(obj));
   MOZ_ASSERT(data);
   HistogramID id = data->histogramId;
   MOZ_ASSERT(internal_IsHistogramEnumId(id));
@@ -1893,13 +1894,13 @@ bool internal_JSHistogram_Snapshot(JSContext* cx, unsigned argc,
   }
 
   if (!args.thisv().isObject() ||
-      JS_GetClass(&args.thisv().toObject()) != &sJSHistogramClass) {
+      JS::GetClass(&args.thisv().toObject()) != &sJSHistogramClass) {
     JS_ReportErrorASCII(cx, "Wrong JS class, expected JSHistogram class");
     return false;
   }
 
   JSObject* obj = &args.thisv().toObject();
-  JSHistogramData* data = static_cast<JSHistogramData*>(JS_GetPrivate(obj));
+  JSHistogramData* data = static_cast<JSHistogramData*>(JS::GetPrivate(obj));
   MOZ_ASSERT(data);
   HistogramID id = data->histogramId;
 
@@ -1956,13 +1957,13 @@ bool internal_JSHistogram_Clear(JSContext* cx, unsigned argc, JS::Value* vp) {
   JS::CallArgs args = JS::CallArgsFromVp(argc, vp);
 
   if (!args.thisv().isObject() ||
-      JS_GetClass(&args.thisv().toObject()) != &sJSHistogramClass) {
+      JS::GetClass(&args.thisv().toObject()) != &sJSHistogramClass) {
     JS_ReportErrorASCII(cx, "Wrong JS class, expected JSHistogram class");
     return false;
   }
 
   JSObject* obj = &args.thisv().toObject();
-  JSHistogramData* data = static_cast<JSHistogramData*>(JS_GetPrivate(obj));
+  JSHistogramData* data = static_cast<JSHistogramData*>(JS::GetPrivate(obj));
   MOZ_ASSERT(data);
 
   nsAutoString storeName;
@@ -2007,19 +2008,19 @@ nsresult internal_WrapAndReturnHistogram(HistogramID id, JSContext* cx,
   }
 
   JSHistogramData* data = new JSHistogramData{id};
-  JS_SetPrivate(obj, data);
+  JS::SetPrivate(obj, data);
   ret.setObject(*obj);
 
   return NS_OK;
 }
 
 void internal_JSHistogram_finalize(JSFreeOp*, JSObject* obj) {
-  if (!obj || JS_GetClass(obj) != &sJSHistogramClass) {
+  if (!obj || JS::GetClass(obj) != &sJSHistogramClass) {
     MOZ_ASSERT_UNREACHABLE("Should have the right JS class.");
     return;
   }
 
-  JSHistogramData* data = static_cast<JSHistogramData*>(JS_GetPrivate(obj));
+  JSHistogramData* data = static_cast<JSHistogramData*>(JS::GetPrivate(obj));
   MOZ_ASSERT(data);
   delete data;
 }
@@ -2072,13 +2073,13 @@ bool internal_JSKeyedHistogram_Snapshot(JSContext* cx, unsigned argc,
   JS::CallArgs args = JS::CallArgsFromVp(argc, vp);
 
   if (!args.thisv().isObject() ||
-      JS_GetClass(&args.thisv().toObject()) != &sJSKeyedHistogramClass) {
+      JS::GetClass(&args.thisv().toObject()) != &sJSKeyedHistogramClass) {
     JS_ReportErrorASCII(cx, "Wrong JS class, expected JSKeyedHistogram class");
     return false;
   }
 
   JSObject* obj = &args.thisv().toObject();
-  JSHistogramData* data = static_cast<JSHistogramData*>(JS_GetPrivate(obj));
+  JSHistogramData* data = static_cast<JSHistogramData*>(JS::GetPrivate(obj));
   MOZ_ASSERT(data);
   HistogramID id = data->histogramId;
   MOZ_ASSERT(internal_IsHistogramEnumId(id));
@@ -2133,13 +2134,13 @@ bool internal_JSKeyedHistogram_Add(JSContext* cx, unsigned argc,
   JS::CallArgs args = JS::CallArgsFromVp(argc, vp);
 
   if (!args.thisv().isObject() ||
-      JS_GetClass(&args.thisv().toObject()) != &sJSKeyedHistogramClass) {
+      JS::GetClass(&args.thisv().toObject()) != &sJSKeyedHistogramClass) {
     JS_ReportErrorASCII(cx, "Wrong JS class, expected JSKeyedHistogram class");
     return false;
   }
 
   JSObject* obj = &args.thisv().toObject();
-  JSHistogramData* data = static_cast<JSHistogramData*>(JS_GetPrivate(obj));
+  JSHistogramData* data = static_cast<JSHistogramData*>(JS::GetPrivate(obj));
   MOZ_ASSERT(data);
   HistogramID id = data->histogramId;
   MOZ_ASSERT(internal_IsHistogramEnumId(id));
@@ -2195,13 +2196,13 @@ bool internal_JSKeyedHistogram_Name(JSContext* cx, unsigned argc,
   JS::CallArgs args = CallArgsFromVp(argc, vp);
 
   if (!args.thisv().isObject() ||
-      JS_GetClass(&args.thisv().toObject()) != &sJSKeyedHistogramClass) {
+      JS::GetClass(&args.thisv().toObject()) != &sJSKeyedHistogramClass) {
     JS_ReportErrorASCII(cx, "Wrong JS class, expected JSKeyedHistogram class");
     return false;
   }
 
   JSObject* obj = &args.thisv().toObject();
-  JSHistogramData* data = static_cast<JSHistogramData*>(JS_GetPrivate(obj));
+  JSHistogramData* data = static_cast<JSHistogramData*>(JS::GetPrivate(obj));
   MOZ_ASSERT(data);
   HistogramID id = data->histogramId;
   MOZ_ASSERT(internal_IsHistogramEnumId(id));
@@ -2218,13 +2219,13 @@ bool internal_JSKeyedHistogram_Keys(JSContext* cx, unsigned argc,
   JS::CallArgs args = JS::CallArgsFromVp(argc, vp);
 
   if (!args.thisv().isObject() ||
-      JS_GetClass(&args.thisv().toObject()) != &sJSKeyedHistogramClass) {
+      JS::GetClass(&args.thisv().toObject()) != &sJSKeyedHistogramClass) {
     JS_ReportErrorASCII(cx, "Wrong JS class, expected JSKeyedHistogram class");
     return false;
   }
 
   JSObject* obj = &args.thisv().toObject();
-  JSHistogramData* data = static_cast<JSHistogramData*>(JS_GetPrivate(obj));
+  JSHistogramData* data = static_cast<JSHistogramData*>(JS::GetPrivate(obj));
   MOZ_ASSERT(data);
   HistogramID id = data->histogramId;
 
@@ -2290,13 +2291,13 @@ bool internal_JSKeyedHistogram_Clear(JSContext* cx, unsigned argc,
   JS::CallArgs args = JS::CallArgsFromVp(argc, vp);
 
   if (!args.thisv().isObject() ||
-      JS_GetClass(&args.thisv().toObject()) != &sJSKeyedHistogramClass) {
+      JS::GetClass(&args.thisv().toObject()) != &sJSKeyedHistogramClass) {
     JS_ReportErrorASCII(cx, "Wrong JS class, expected JSKeyedHistogram class");
     return false;
   }
 
   JSObject* obj = &args.thisv().toObject();
-  JSHistogramData* data = static_cast<JSHistogramData*>(JS_GetPrivate(obj));
+  JSHistogramData* data = static_cast<JSHistogramData*>(JS::GetPrivate(obj));
   MOZ_ASSERT(data);
   HistogramID id = data->histogramId;
 
@@ -2353,19 +2354,19 @@ nsresult internal_WrapAndReturnKeyedHistogram(
   }
 
   JSHistogramData* data = new JSHistogramData{id};
-  JS_SetPrivate(obj, data);
+  JS::SetPrivate(obj, data);
   ret.setObject(*obj);
 
   return NS_OK;
 }
 
 void internal_JSKeyedHistogram_finalize(JSFreeOp*, JSObject* obj) {
-  if (!obj || JS_GetClass(obj) != &sJSKeyedHistogramClass) {
+  if (!obj || JS::GetClass(obj) != &sJSKeyedHistogramClass) {
     MOZ_ASSERT_UNREACHABLE("Should have the right JS class.");
     return;
   }
 
-  JSHistogramData* data = static_cast<JSHistogramData*>(JS_GetPrivate(obj));
+  JSHistogramData* data = static_cast<JSHistogramData*>(JS::GetPrivate(obj));
   MOZ_ASSERT(data);
   delete data;
 }
diff --git a/toolkit/components/telemetry/core/TelemetryOrigin.cpp b/toolkit/components/telemetry/core/TelemetryOrigin.cpp
index 1b20053d86..2fc672caf1 100644
--- a/toolkit/components/telemetry/core/TelemetryOrigin.cpp
+++ b/toolkit/components/telemetry/core/TelemetryOrigin.cpp
@@ -16,7 +16,6 @@
 #include "mozilla/Atomics.h"
 #include "mozilla/Base64.h"
 #include "mozilla/Preferences.h"
-#include "mozilla/Pair.h"
 #include "mozilla/Services.h"
 #include "mozilla/StaticMutex.h"
 #include "mozilla/Tuple.h"
@@ -26,11 +25,9 @@
 #include <type_traits>
 
 using mozilla::Get;
-using mozilla::MakePair;
 using mozilla::MakeTuple;
 using mozilla::MakeUnique;
 using mozilla::MallocSizeOf;
-using mozilla::Pair;
 using mozilla::StaticMutex;
 using mozilla::StaticMutexAutoLock;
 using mozilla::Tuple;
@@ -125,7 +122,7 @@ UniquePtr<IdToOriginBag> gMetricToOriginBag;
 mozilla::Atomic<bool, mozilla::Relaxed> gInitDone(false);
 
 // Useful for app-encoded data
-typedef nsTArray<Pair<OriginMetricID, nsTArray<nsTArray<bool>>>>
+typedef nsTArray<std::pair<OriginMetricID, nsTArray<nsTArray<bool>>>>
     IdBoolsPairArray;
 
 // Prio has a maximum supported number of bools it can encode at a time.
@@ -196,9 +193,7 @@ nsresult AppEncodeTo(const StaticMutexAutoLock& lock,
 //
 // EXTERNALLY VISIBLE FUNCTIONS in namespace TelemetryOrigin::
 
-void TelemetryOrigin::InitializeGlobalState() {
-  gInitDone = false;
-}
+void TelemetryOrigin::InitializeGlobalState() { gInitDone = false; }
 
 void TelemetryOrigin::DeInitializeGlobalState() {
   if (!XRE_IsParentProcess()) {
@@ -333,7 +328,7 @@ nsresult TelemetryOrigin::GetOriginSnapshot(bool aClear, JSContext* aCx,
 
 nsresult TelemetryOrigin::GetEncodedOriginSnapshot(
     bool aClear, JSContext* aCx, JS::MutableHandleValue aSnapshot) {
-    return NS_ERROR_FAILURE;
+  return NS_ERROR_FAILURE;
 }
 
 /**
diff --git a/toolkit/components/telemetry/core/TelemetryScalar.cpp b/toolkit/components/telemetry/core/TelemetryScalar.cpp
index 9c9f5f0069..9ebf0524a7 100644
--- a/toolkit/components/telemetry/core/TelemetryScalar.cpp
+++ b/toolkit/components/telemetry/core/TelemetryScalar.cpp
@@ -822,7 +822,7 @@ ScalarBase* internal_ScalarAllocate(const BaseScalarInfo& aInfo) {
  */
 class KeyedScalar {
  public:
-  typedef mozilla::Pair<nsCString, nsCOMPtr<nsIVariant>> KeyValuePair;
+  typedef std::pair<nsCString, nsCOMPtr<nsIVariant>> KeyValuePair;
 
   explicit KeyedScalar(const BaseScalarInfo& info)
       : mScalarName(info.name()), mMaximumNumberOfKeys(kMaximumNumberOfKeys){};
@@ -997,8 +997,7 @@ nsresult KeyedScalar::GetValue(const nsACString& aStoreName, bool aClearStorage,
     }
 
     // Append it to value list.
-    aValues.AppendElement(
-        mozilla::MakePair(nsCString(iter.Key()), scalarValue));
+    aValues.AppendElement(std::make_pair(nsCString(iter.Key()), scalarValue));
   }
 
   return NS_OK;
@@ -3243,13 +3242,13 @@ nsresult TelemetryScalar::CreateKeyedSnapshots(
         // Convert the value for the key to a JSValue.
         JS::Rooted<JS::Value> keyJsValue(aCx);
         nsresult rv = nsContentUtils::XPConnect()->VariantToJS(
-            aCx, keyedScalarObj, keyData.second(), &keyJsValue);
+            aCx, keyedScalarObj, keyData.second, &keyJsValue);
         if (NS_FAILED(rv)) {
           return rv;
         }
 
         // Add the key to the scalar representation.
-        const NS_ConvertUTF8toUTF16 key(keyData.first());
+        const NS_ConvertUTF8toUTF16 key(keyData.first);
         if (!JS_DefineUCProperty(aCx, keyedScalarObj, key.Data(), key.Length(),
                                  keyJsValue, JSPROP_ENUMERATE)) {
           return NS_ERROR_FAILURE;
@@ -3814,8 +3813,8 @@ nsresult TelemetryScalar::SerializeKeyedScalars(mozilla::JSONWriter& aWriter) {
       for (const KeyedScalar::KeyValuePair& keyData : keyProps) {
         nsresult rv = WriteVariantToJSONWriter(
             mozilla::Get<2>(keyedScalarData) /*aScalarType*/,
-            keyData.second() /*aInputValue*/,
-            PromiseFlatCString(keyData.first()).get() /*aOutKey*/,
+            keyData.second /*aInputValue*/,
+            PromiseFlatCString(keyData.first).get() /*aOutKey*/,
             aWriter /*aWriter*/);
         if (NS_FAILED(rv)) {
           // Skip this scalar if we failed to write it. We don't bail out just
@@ -3847,7 +3846,7 @@ nsresult TelemetryScalar::DeserializePersistedScalars(JSContext* aCx,
     return NS_ERROR_FAILURE;
   }
 
-  typedef mozilla::Pair<nsCString, nsCOMPtr<nsIVariant>> PersistedScalarPair;
+  typedef std::pair<nsCString, nsCOMPtr<nsIVariant>> PersistedScalarPair;
   typedef nsTArray<PersistedScalarPair> PersistedScalarArray;
   typedef nsDataHashtable<ProcessIDHashKey, PersistedScalarArray>
       PeristedScalarStorage;
@@ -3950,7 +3949,7 @@ nsresult TelemetryScalar::DeserializePersistedScalars(JSContext* aCx,
       // Add the scalar to the map.
       PersistedScalarArray& processScalars =
           scalarsToUpdate.GetOrInsert(static_cast<uint32_t>(processID));
-      processScalars.AppendElement(mozilla::MakePair(
+      processScalars.AppendElement(std::make_pair(
           nsCString(NS_ConvertUTF16toUTF8(scalarName)), unpackedVal));
     }
   }
@@ -3964,9 +3963,8 @@ nsresult TelemetryScalar::DeserializePersistedScalars(JSContext* aCx,
       for (PersistedScalarArray::size_type i = 0; i < processScalars.Length();
            i++) {
         mozilla::Unused << internal_UpdateScalar(
-            lock, processScalars[i].first(), ScalarActionType::eSet,
-            processScalars[i].second(), ProcessID(iter.Key()),
-            true /* aForce */);
+            lock, processScalars[i].first, ScalarActionType::eSet,
+            processScalars[i].second, ProcessID(iter.Key()), true /* aForce */);
       }
     }
   }
diff --git a/toolkit/components/telemetry/core/components.conf b/toolkit/components/telemetry/core/components.conf
index fb7ee858cf..0d766160f1 100644
--- a/toolkit/components/telemetry/core/components.conf
+++ b/toolkit/components/telemetry/core/components.conf
@@ -8,8 +8,10 @@ UnloadFunc = 'mozilla::Telemetry::ShutdownTelemetry'
 
 Classes = [
     {
+        'js_name': 'telemetry',
         'cid': '{aea477f2-b3a2-469c-aa29-0a82d132b829}',
         'contract_ids': ['@mozilla.org/base/telemetry;1'],
+        'interfaces': ['nsITelemetry'],
         'singleton': True,
         'type': 'nsITelemetry',
         'processes': ProcessSelector.ALLOW_IN_GPU_RDD_VR_AND_SOCKET_PROCESS,
diff --git a/toolkit/components/telemetry/core/ipc/TelemetryIPCAccumulator.cpp b/toolkit/components/telemetry/core/ipc/TelemetryIPCAccumulator.cpp
index 2015df91e6..50f9d3ec64 100644
--- a/toolkit/components/telemetry/core/ipc/TelemetryIPCAccumulator.cpp
+++ b/toolkit/components/telemetry/core/ipc/TelemetryIPCAccumulator.cpp
@@ -254,19 +254,19 @@ static void SendAccumulatedData(TActor* ipcActor) {
   {
     StaticMutexAutoLock locker(gTelemetryIPCAccumulatorMutex);
     if (gHistogramAccumulations) {
-      histogramsToSend.SwapElements(*gHistogramAccumulations);
+      histogramsToSend = std::move(*gHistogramAccumulations);
     }
     if (gKeyedHistogramAccumulations) {
-      keyedHistogramsToSend.SwapElements(*gKeyedHistogramAccumulations);
+      keyedHistogramsToSend = std::move(*gKeyedHistogramAccumulations);
     }
     if (gChildScalarsActions) {
-      scalarsToSend.SwapElements(*gChildScalarsActions);
+      scalarsToSend = std::move(*gChildScalarsActions);
     }
     if (gChildKeyedScalarsActions) {
-      keyedScalarsToSend.SwapElements(*gChildKeyedScalarsActions);
+      keyedScalarsToSend = std::move(*gChildKeyedScalarsActions);
     }
     if (gChildEvents) {
-      eventsToSend.SwapElements(*gChildEvents);
+      eventsToSend = std::move(*gChildEvents);
     }
     discardedData = gDiscardedData;
     gDiscardedData = {0};
diff --git a/toolkit/components/telemetry/core/nsITelemetry.idl b/toolkit/components/telemetry/core/nsITelemetry.idl
index 72d76d059d..7ad81e651e 100644
--- a/toolkit/components/telemetry/core/nsITelemetry.idl
+++ b/toolkit/components/telemetry/core/nsITelemetry.idl
@@ -178,14 +178,6 @@ interface nsITelemetry : nsISupports
   [implicit_jscontext]
   readonly attribute jsval debugSlowSQL;
 
-  /*
-   * An object containing information about Webrtc related stats. For now it
-   * only contains local and remote ICE candidates avaiable when a Webrtc
-   * PeerConnection gets terminated.
-   */
-  [implicit_jscontext]
-  readonly attribute jsval webrtcStats;
-
   /**
    * A number representing the highest number of concurrent threads
    * reached during this session.
diff --git a/toolkit/components/telemetry/docs/data/main-ping.rst b/toolkit/components/telemetry/docs/data/main-ping.rst
index 27694a4d7d..5aed3c9f3a 100644
--- a/toolkit/components/telemetry/docs/data/main-ping.rst
+++ b/toolkit/components/telemetry/docs/data/main-ping.rst
@@ -67,7 +67,6 @@ Structure:
       threadHangStats: [...], // obsolete in firefox 57, use the 'bhr' ping
       capturedStacks: {...},
       log: [...], // obsolete in firefox 61, use Event Telemetry or Scalars
-      webrtc: {...},
       gc: {...},
       fileIOReports: {...},
       lateWrites: {...},
@@ -399,151 +398,6 @@ At present there is one known users of this section: Telemetry Experiments.
 
 Telemetry Experiments uses it to note when experiments are activated and terminated.
 
-webrtc
-------
-Contains special statistics gathered by WebRTC related components.
-
-So far only a bitmask for the ICE candidate type present in a successful or
-failed WebRTC connection is getting reported through C++ code as
-IceCandidatesStats, because the required bitmask is too big to be represented
-in a regular enum histogram.
-
-Note: in most cases the webrtc dictionary inside of
-IceCandidatesStats will simply be empty as the user has not used any WebRTC
-PeerConnection at all during the ping report time.
-
-Structure:
-
-.. code-block:: js
-
-    "webrtc": {
-      "IceCandidatesStats": {
-        "webrtc": {
-          "34526345": {
-            "successCount": 5
-          },
-          "2354353": {
-            "failureCount": 1
-          }
-        },
-      }
-    },
-
-gc
---
-Contains statistics about selected garbage collections. To avoid
-bloating the ping, only a few GCs are included. There are two
-selection strategies. We always save the two GCs with the worst
-max_pause time. Additionally, in content processes, two collections
-are selected at random. If a GC runs for C milliseconds and the total
-time for all GCs since the session began is T milliseconds, then the
-GC has a C/T probablility of being selected for one of these "slots".
-
-Structure:
-
-.. code-block:: js
-
-    "gc": {
-      "random": [
-        {
-          // "completed" or "aborted" if an OOM occurred.
-          "status": "completed",
-          // Timestamps are in milliseconds since startup. All the times here
-          // are wall-clock times, which may not be monotonically increasing.
-          "timestamp": 294872.2,
-          // All durations are in milliseconds.
-          "max_pause": 73.629,
-          "total_time": 364.951, // Sum of all slice times.
-          "zones_collected": 9,
-          "total_zones": 9,
-          "total_compartments": 309,
-          "minor_gcs": 44,
-          // Present if non-zero.
-          "store_buffer_overflows": 19,
-          "mmu_20ms": 0,
-          "mmu_50ms": 0,
-          // Reasons include "None", "NonIncrementalRequested",
-          // "AbortRequested", "KeepAtomsSet", "IncrementalDisabled",
-          // "ModeChange", "MallocBytesTrigger", "GCBytesTrigger",
-          // "ZoneChange", "CompartmentRevived".
-          // Present for non-incremental GCs only.
-          "nonincremental_reason": "GCBytesTrigger",
-          "allocated_bytes": 38853696 // in bytes
-
-          // Present if non-zero.
-          "added_chunks": 54,
-          "removed_chunks": 12,
-
-          // Total number of slices (some of which may not appear
-          // in the "slices" array).
-          "slices": 15,
-          // We record at most 4 slices.
-          "slice_number": 218, // The first slice number for this GC event.
-          "slices_list": [
-            {
-              "slice": 218,  // The global index of this slice.
-              "pause": 23.221,  // How long the slice took (milliseconds).
-              "reason": "SET_NEW_DOCUMENT",
-              // GC state when the slice started
-              "initial_state": "NotActive",
-              // GC state when the slice ended
-              "final_state": "Mark",
-              // Budget is either "Xms", "work(Y)", or
-              // "unlimited".
-              "budget": "10ms",
-              // Number of page faults during the slice.
-              // optional field, missing means 0.
-              "page_faults": 1,
-              // The start time of this slice in seconds.  The end time is
-              // given by the start_timestamp + pause.
-              "start_timestamp": 294875,
-              // Time taken by each phase. There are at most 65 possible
-              // phases, but usually only a few phases run in a given slice.
-              "times": {
-                "wait_background_thread": 0.012,
-                "mark_discard_code": 2.845,
-                "purge": 0.723,
-                "mark": 9.831,
-                "mark_roots": 0.102,
-                "buffer_gray_roots": 3.095,
-                "mark_cross_compartment_wrappers": 0.039,
-                "mark_c_and_js_stacks": 0.005,
-                "mark_runtime_wide_data": 2.313,
-                "mark_embedding": 0.117,
-                "mark_compartments": 2.27,
-                "unmark": 1.063,
-                "minor_gcs_to_evict_nursery": 8.701,
-                ...
-              }
-            },
-            { ... },
-          ],
-          // Sum of the phase times across all slices, including
-          // omitted slices. As before, there are <= 65 possible phases.
-          "totals": {
-            "wait_background_thread": 0.012,
-            "mark_discard_code": 2.845,
-            "purge": 0.723,
-            "mark": 9.831,
-            "mark_roots": 0.102,
-            "buffer_gray_roots": 3.095,
-            "mark_cross_compartment_wrappers": 0.039,
-            "mark_c_and_js_stacks": 0.005,
-            "mark_runtime_wide_data": 2.313,
-            "mark_embedding": 0.117,
-            "mark_compartments": 2.27,
-            "unmark": 1.063,
-            "minor_gcs_to_evict_nursery": 8.701,
-            ...
-          }
-        },
-        ... // Up to four more selected GCs follow.
-      ],
-      "worst": [
-        ... // Same as above, but the 2 worst GCs by max_pause.
-      ]
-    },
-
 fileIOReports
 -------------
 Contains the statistics of main-thread I/O recorded during the execution. Only the I/O stats for the XRE and the profile directories are currently reported, neither of them disclosing the full local path.
@@ -682,3 +536,7 @@ Version History
 - Firefox 62:
 
   - ``events`` are now reported via the :doc:`../data/event-ping` (`bug 1460595 <https://bugzilla.mozilla.org/show_bug.cgi?id=1460595>`_).
+
+- Firefox 80:
+
+  - Stopped reporting ``GCTelemetry`` (`bug 1482089 <https://bugzilla.mozilla.org/show_bug.cgi?id=1482089>`_).
diff --git a/toolkit/components/telemetry/geckoview/GeckoViewTelemetryController.jsm b/toolkit/components/telemetry/geckoview/GeckoViewTelemetryController.jsm
index e4761b698c..3e24565ace 100644
--- a/toolkit/components/telemetry/geckoview/GeckoViewTelemetryController.jsm
+++ b/toolkit/components/telemetry/geckoview/GeckoViewTelemetryController.jsm
@@ -23,8 +23,6 @@ const { debug, warn } = GeckoViewUtils.initLogging(
 
 var EXPORTED_SYMBOLS = ["GeckoViewTelemetryController"];
 
-/* global debug warn */
-
 // Persistent data loading topic - see TelemetryGeckoViewPersistence.cpp.
 const LOAD_COMPLETE_TOPIC = "internal-telemetry-geckoview-load-complete";
 
diff --git a/toolkit/components/telemetry/histogram-whitelists.json b/toolkit/components/telemetry/histogram-whitelists.json
index 62cc232877..be84287411 100644
--- a/toolkit/components/telemetry/histogram-whitelists.json
+++ b/toolkit/components/telemetry/histogram-whitelists.json
@@ -659,12 +659,9 @@
     "FX_THUMBNAILS_STORE_TIME_MS",
     "FX_TOTAL_TOP_VISITS",
     "FX_TOUCH_USED",
-    "GC_BUDGET_MS",
     "GC_COMPACT_MS",
     "GC_IS_COMPARTMENTAL",
-    "GC_MARK_GRAY_MS",
     "GC_MARK_MS",
-    "GC_MARK_ROOTS_MS",
     "GC_MINOR_REASON",
     "GC_MINOR_REASON_LONG",
     "GC_MINOR_US",
diff --git a/toolkit/components/telemetry/moz.build b/toolkit/components/telemetry/moz.build
index 44e5b370a8..dd61d3a1b3 100644
--- a/toolkit/components/telemetry/moz.build
+++ b/toolkit/components/telemetry/moz.build
@@ -43,7 +43,6 @@ BROWSER_CHROME_MANIFESTS += ['tests/browser/browser.ini']
 
 XPIDL_SOURCES += [
     'core/nsITelemetry.idl',
-    'other/GCTelemetry.idl',
 ]
 
 XPIDL_MODULE = 'telemetry'
@@ -79,7 +78,6 @@ SOURCES += [
     'other/CombinedStacks.cpp',
     'other/ProcessedStack.cpp',
     #'other/TelemetryIOInterposeObserver.cpp',
-    'other/WebrtcTelemetry.cpp',
 ]
 
 if CONFIG['OS_ARCH'] == 'WINNT':
@@ -113,7 +111,6 @@ EXTRA_JS_MODULES += [
     'app/TelemetryStorage.jsm',
     'app/TelemetryTimestamps.jsm',
     'app/TelemetryUtils.jsm',
-    'other/GCTelemetry.jsm',
     'other/UITelemetry.jsm',
     'pings/CoveragePing.jsm',
     'pings/EcosystemTelemetry.jsm',
diff --git a/toolkit/components/telemetry/other/GCTelemetry.idl b/toolkit/components/telemetry/other/GCTelemetry.idl
deleted file mode 100644
index 1f92b73813..0000000000
--- a/toolkit/components/telemetry/other/GCTelemetry.idl
+++ /dev/null
@@ -1,17 +0,0 @@
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-#include "nsISupports.idl"
-
-[scriptable, uuid(6ab1c3c1-31cf-4a32-8484-97b5ef0627af)]
-interface mozIGCTelemetry : nsISupports {
-  void init();
-
-  void shutdown();
-};
-
-[scriptable, uuid(93b2a0ca-6306-41c1-b296-c57cad5175c7)]
-interface mozIGCTelemetryJSM : nsISupports {
-  readonly attribute mozIGCTelemetry GCTelemetry;
-};
diff --git a/toolkit/components/telemetry/other/GCTelemetry.jsm b/toolkit/components/telemetry/other/GCTelemetry.jsm
deleted file mode 100644
index 1a446e03db..0000000000
--- a/toolkit/components/telemetry/other/GCTelemetry.jsm
+++ /dev/null
@@ -1,251 +0,0 @@
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-"use strict";
-
-/**
- * This module records detailed timing information about selected
- * GCs. The data is sent back in the telemetry session ping. To avoid
- * bloating the ping, only a few GCs are included. There are two
- * selection strategies. We always save the two GCs with the worst
- * max_pause time. Additionally, two collections are selected at
- * random. If a GC runs for C milliseconds and the total time for all
- * GCs since the session began is T milliseconds, then the GC has a
- * 2*C/T probablility of being selected (the factor of 2 is because we
- * save two of them).
- *
- * GCs from both the main process and all content processes are
- * recorded. The data is cleared for each new subsession.
- */
-
-ChromeUtils.import("resource://gre/modules/Services.jsm", this);
-const { Log } = ChromeUtils.import("resource://gre/modules/Log.jsm");
-
-var EXPORTED_SYMBOLS = ["GCTelemetry"];
-
-// Names of processes where we record GCs.
-const PROCESS_NAMES = ["main", "content"];
-
-// Should be the time we started up in milliseconds since the epoch.
-const BASE_TIME = Date.now() - Services.telemetry.msSinceProcessStart();
-
-// Records selected GCs. There is one instance per process type.
-class GCData {
-  constructor(kind) {
-    let numRandom = { main: 0, content: 2 };
-    let numWorst = { main: 2, content: 2 };
-
-    this.totalGCTime = 0;
-    this.randomlySelected = Array(numRandom[kind]).fill(null);
-    this.worst = Array(numWorst[kind]).fill(null);
-  }
-
-  // Turn absolute timestamps (in microseconds since the epoch) into
-  // milliseconds since startup.
-  rebaseTimes(data) {
-    function fixup(t) {
-      return t / 1000.0 - BASE_TIME;
-    }
-
-    data.timestamp = fixup(data.timestamp);
-
-    for (let i = 0; i < data.slices_list.length; i++) {
-      let slice = data.slices_list[i];
-      slice.start_timestamp = fixup(slice.start_timestamp);
-      // Slices have no end_timestamp, instead they have a duration.
-    }
-  }
-
-  // Records a GC (represented by |data|) in the randomlySelected or
-  // worst batches depending on the criteria above.
-  record(data) {
-    this.rebaseTimes(data);
-
-    let time = data.total_time;
-    this.totalGCTime += time;
-
-    // Probability that we will replace any one of our
-    // current randomlySelected GCs with |data|.
-    let prob = time / this.totalGCTime;
-
-    // Note that we may replace multiple GCs in
-    // randomlySelected. It's easier to reason about the
-    // probabilities this way, and it's unlikely to have any effect in
-    // practice.
-    for (let i = 0; i < this.randomlySelected.length; i++) {
-      let r = Math.random();
-      if (r <= prob) {
-        this.randomlySelected[i] = data;
-      }
-    }
-
-    // Save the 2 worst GCs based on max_pause. A GC may appear in
-    // both worst and randomlySelected.
-    for (let i = 0; i < this.worst.length; i++) {
-      if (!this.worst[i]) {
-        this.worst[i] = data;
-        break;
-      }
-
-      if (this.worst[i].max_pause < data.max_pause) {
-        this.worst.splice(i, 0, data);
-        this.worst.length--;
-        break;
-      }
-    }
-  }
-
-  entries() {
-    return {
-      random: this.randomlySelected.filter(e => e !== null),
-      worst: this.worst.filter(e => e !== null),
-    };
-  }
-}
-
-// If you adjust any of the constants here (slice limit, number of keys, etc.)
-// make sure to update the JSON schema at:
-// https://github.com/mozilla-services/mozilla-pipeline-schemas/blob/master/telemetry/main.schema.json
-// You should also adjust browser_TelemetryGC.js.
-const MAX_GC_KEYS = 24;
-const MAX_SLICES = 4;
-const MAX_SLICE_KEYS = 12;
-const MAX_PHASES = 65;
-const LOGGER_NAME = "Toolkit.Telemetry";
-
-function limitProperties(name, obj, count, log) {
-  // If there are too many properties delete all/most of them. We don't
-  // expect this ever to happen.
-  let num_properties = Object.keys(obj).length;
-  if (num_properties > count) {
-    for (let key of Object.keys(obj)) {
-      // If this is the main GC object then save some of the critical
-      // properties.
-      if (
-        name === "data" &&
-        (key === "max_pause" ||
-          key === "slices" ||
-          key === "slices_list" ||
-          key === "status" ||
-          key === "timestamp" ||
-          key === "total_time" ||
-          key === "totals")
-      ) {
-        continue;
-      }
-
-      delete obj[key];
-    }
-    let log_fn;
-    if (name === "slice.times" || name === "data.totals") {
-      // This is a bit more likely, but is mostly-okay.
-      log_fn = s => log.info(s);
-    } else {
-      log_fn = s => log.warn(s);
-    }
-    log_fn(
-      `Number of properties exceeded in the GC telemetry ${name} ping, expected ${count} got ${num_properties}`
-    );
-  }
-}
-
-/*
- * Reduce the size of the object by limiting the number of slices or times
- * etc.
- */
-function limitSize(data, log) {
-  data.slices_list.sort((a, b) => b.pause - a.pause);
-
-  if (data.slices_list.length > MAX_SLICES) {
-    // Make sure we always keep the first slice since it has the
-    // reason the GC was started.
-    let firstSliceIndex = data.slices_list.findIndex(s => s.slice == 0);
-    if (firstSliceIndex >= MAX_SLICES) {
-      data.slices_list[MAX_SLICES - 1] = data.slices_list[firstSliceIndex];
-    }
-
-    data.slices_list.length = MAX_SLICES;
-  }
-
-  data.slices_list.sort((a, b) => a.slice - b.slice);
-
-  limitProperties("data", data, MAX_GC_KEYS, log);
-
-  for (let slice of data.slices_list) {
-    limitProperties("slice", slice, MAX_SLICE_KEYS, log);
-    limitProperties("slice.times", slice.times, MAX_PHASES, log);
-  }
-
-  limitProperties("data.totals", data.totals, MAX_PHASES, log);
-}
-
-let processData = new Map();
-for (let name of PROCESS_NAMES) {
-  processData.set(name, new GCData(name));
-}
-
-var GCTelemetry = {
-  initialized: false,
-
-  init() {
-    if (this.initialized) {
-      return false;
-    }
-
-    this.initialized = true;
-    this._log = Log.repository.getLoggerWithMessagePrefix(
-      LOGGER_NAME,
-      "GCTelemetry::"
-    );
-
-    Services.obs.addObserver(this, "garbage-collection-statistics");
-
-    if (Services.appinfo.processType == Services.appinfo.PROCESS_TYPE_DEFAULT) {
-      Services.ppmm.addMessageListener("Telemetry:GCStatistics", this);
-    }
-
-    return true;
-  },
-
-  shutdown() {
-    if (!this.initialized) {
-      return;
-    }
-
-    Services.obs.removeObserver(this, "garbage-collection-statistics");
-
-    if (Services.appinfo.processType == Services.appinfo.PROCESS_TYPE_DEFAULT) {
-      Services.ppmm.removeMessageListener("Telemetry:GCStatistics", this);
-    }
-    this.initialized = false;
-  },
-
-  observe(subject, topic, arg) {
-    this.observeRaw(JSON.parse(arg));
-  },
-
-  // We expose this method so unit tests can call it, no need to test JSON
-  // parsing.
-  observeRaw(data) {
-    limitSize(data, this._log);
-
-    if (Services.appinfo.processType == Services.appinfo.PROCESS_TYPE_DEFAULT) {
-      processData.get("main").record(data);
-    } else {
-      Services.cpmm.sendAsyncMessage("Telemetry:GCStatistics", data);
-    }
-  },
-
-  receiveMessage(msg) {
-    processData.get("content").record(msg.data);
-  },
-
-  entries(kind, clear) {
-    let result = processData.get(kind).entries();
-    if (clear) {
-      processData.set(kind, new GCData(kind));
-    }
-    return result;
-  },
-};
diff --git a/toolkit/components/telemetry/other/WebrtcTelemetry.cpp b/toolkit/components/telemetry/other/WebrtcTelemetry.cpp
deleted file mode 100644
index 475cfec7f0..0000000000
--- a/toolkit/components/telemetry/other/WebrtcTelemetry.cpp
+++ /dev/null
@@ -1,89 +0,0 @@
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-#include "WebrtcTelemetry.h"
-
-#include "jsapi.h"
-#include "mozilla/Telemetry.h"
-#include "nsPrintfCString.h"
-#include "nsTHashtable.h"
-void WebrtcTelemetry::RecordIceCandidateMask(const uint32_t iceCandidateBitmask,
-                                             const bool success) {
-  WebrtcIceCandidateType* entry =
-      mWebrtcIceCandidates.GetEntry(iceCandidateBitmask);
-  if (!entry) {
-    entry = mWebrtcIceCandidates.PutEntry(iceCandidateBitmask);
-    if (MOZ_UNLIKELY(!entry)) return;
-  }
-
-  if (success) {
-    entry->GetModifiableData()->webrtc.successCount++;
-  } else {
-    entry->GetModifiableData()->webrtc.failureCount++;
-  }
-}
-
-bool ReflectIceEntry(const WebrtcTelemetry::WebrtcIceCandidateType* entry,
-                     const WebrtcTelemetry::WebrtcIceCandidateStats* stat,
-                     JSContext* cx, JS::Handle<JSObject*> obj) {
-  if ((stat->successCount == 0) && (stat->failureCount == 0)) return true;
-
-  const uint32_t& bitmask = entry->GetKey();
-
-  JS::Rooted<JSObject*> statsObj(cx, JS_NewPlainObject(cx));
-  if (!statsObj) return false;
-  if (!JS_DefineProperty(cx, obj,
-                         nsPrintfCString("%" PRIu32, bitmask).BeginReading(),
-                         statsObj, JSPROP_ENUMERATE)) {
-    return false;
-  }
-  if (stat->successCount &&
-      !JS_DefineProperty(cx, statsObj, "successCount", stat->successCount,
-                         JSPROP_ENUMERATE)) {
-    return false;
-  }
-  if (stat->failureCount &&
-      !JS_DefineProperty(cx, statsObj, "failureCount", stat->failureCount,
-                         JSPROP_ENUMERATE)) {
-    return false;
-  }
-  return true;
-}
-
-bool ReflectIceWebrtc(WebrtcTelemetry::WebrtcIceCandidateType* entry,
-                      JSContext* cx, JS::Handle<JSObject*> obj) {
-  return ReflectIceEntry(entry, &entry->GetData().webrtc, cx, obj);
-}
-
-bool WebrtcTelemetry::AddIceInfo(JSContext* cx, JS::Handle<JSObject*> iceObj) {
-  JS::Rooted<JSObject*> statsObj(cx, JS_NewPlainObject(cx));
-  if (!statsObj) return false;
-
-  if (!mWebrtcIceCandidates.ReflectIntoJS(ReflectIceWebrtc, cx, statsObj)) {
-    return false;
-  }
-
-  return JS_DefineProperty(cx, iceObj, "webrtc", statsObj, JSPROP_ENUMERATE);
-}
-
-bool WebrtcTelemetry::GetWebrtcStats(JSContext* cx,
-                                     JS::MutableHandle<JS::Value> ret) {
-  JS::Rooted<JSObject*> root_obj(cx, JS_NewPlainObject(cx));
-  if (!root_obj) return false;
-  ret.setObject(*root_obj);
-
-  JS::Rooted<JSObject*> ice_obj(cx, JS_NewPlainObject(cx));
-  if (!ice_obj) return false;
-  JS_DefineProperty(cx, root_obj, "IceCandidatesStats", ice_obj,
-                    JSPROP_ENUMERATE);
-
-  if (!AddIceInfo(cx, ice_obj)) return false;
-
-  return true;
-}
-
-size_t WebrtcTelemetry::SizeOfExcludingThis(
-    mozilla::MallocSizeOf aMallocSizeOf) const {
-  return mWebrtcIceCandidates.ShallowSizeOfExcludingThis(aMallocSizeOf);
-}
diff --git a/toolkit/components/telemetry/other/WebrtcTelemetry.h b/toolkit/components/telemetry/other/WebrtcTelemetry.h
deleted file mode 100644
index 5e2545632a..0000000000
--- a/toolkit/components/telemetry/other/WebrtcTelemetry.h
+++ /dev/null
@@ -1,38 +0,0 @@
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-#ifndef WebrtcTelemetry_h__
-#define WebrtcTelemetry_h__
-
-#include "nsBaseHashtable.h"
-#include "nsHashKeys.h"
-#include "core/TelemetryCommon.h"
-
-class WebrtcTelemetry {
- public:
-  struct WebrtcIceCandidateStats {
-    uint32_t successCount;
-    uint32_t failureCount;
-    WebrtcIceCandidateStats() : successCount(0), failureCount(0) {}
-  };
-  struct WebrtcIceStatsCategory {
-    struct WebrtcIceCandidateStats webrtc;
-  };
-  typedef nsBaseHashtableET<nsUint32HashKey, WebrtcIceStatsCategory>
-      WebrtcIceCandidateType;
-
-  void RecordIceCandidateMask(const uint32_t iceCandidateBitmask, bool success);
-
-  bool GetWebrtcStats(JSContext* cx, JS::MutableHandle<JS::Value> ret);
-
-  size_t SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const;
-
- private:
-  bool AddIceInfo(JSContext* cx, JS::Handle<JSObject*> rootObj);
-
-  mozilla::Telemetry::Common::AutoHashtable<WebrtcIceCandidateType>
-      mWebrtcIceCandidates;
-};
-
-#endif  // WebrtcTelemetry_h__
diff --git a/toolkit/components/telemetry/pings/TelemetrySession.jsm b/toolkit/components/telemetry/pings/TelemetrySession.jsm
index ae65d30f69..11e5d6550a 100644
--- a/toolkit/components/telemetry/pings/TelemetrySession.jsm
+++ b/toolkit/components/telemetry/pings/TelemetrySession.jsm
@@ -17,7 +17,6 @@ XPCOMUtils.defineLazyModuleGetters(this, {
   TelemetryController: "resource://gre/modules/TelemetryController.jsm",
   TelemetryStorage: "resource://gre/modules/TelemetryStorage.jsm",
   UITelemetry: "resource://gre/modules/UITelemetry.jsm",
-  GCTelemetry: "resource://gre/modules/GCTelemetry.jsm",
   TelemetryEnvironment: "resource://gre/modules/TelemetryEnvironment.jsm",
   TelemetryReportingPolicy:
     "resource://gre/modules/TelemetryReportingPolicy.jsm",
@@ -627,7 +626,6 @@ var Impl = {
     // Add extended set measurements common to chrome & content processes
     if (Telemetry.canRecordExtended) {
       payloadObj.log = [];
-      payloadObj.webrtc = protect(() => Telemetry.webrtcStats);
     }
 
     if (Utils.isContentProcess) {
@@ -727,15 +725,6 @@ var Impl = {
         payloadObj.slowSQLStartup = this._slowSQLStartup;
       }
 
-      if (!this._isClassicReason(reason)) {
-        payloadObj.processes.parent.gc = protect(() =>
-          GCTelemetry.entries("main", clearSubsession)
-        );
-        payloadObj.processes.content.gc = protect(() =>
-          GCTelemetry.entries("content", clearSubsession)
-        );
-      }
-
       // Adding captured stacks to the payload only if any exist and clearing
       // captures for this sub-session.
       let stacks = protect(() => Telemetry.snapshotCapturedStacks(true));
diff --git a/toolkit/components/telemetry/tests/browser/browser.ini b/toolkit/components/telemetry/tests/browser/browser.ini
index 3271caf76b..584bf7d39b 100644
--- a/toolkit/components/telemetry/tests/browser/browser.ini
+++ b/toolkit/components/telemetry/tests/browser/browser.ini
@@ -2,7 +2,6 @@
 # License, v. 2.0. If a copy of the MPL was not distributed with this
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
-[browser_TelemetryGC.js]
 [browser_UpdatePingSuccess.js]
 [browser_DynamicScalars.js]
 skip-if = !e10s || verify # e10s specific test for definition broadcasting across processes.
diff --git a/toolkit/components/telemetry/tests/browser/browser_TelemetryGC.js b/toolkit/components/telemetry/tests/browser/browser_TelemetryGC.js
deleted file mode 100644
index 9cc1480beb..0000000000
--- a/toolkit/components/telemetry/tests/browser/browser_TelemetryGC.js
+++ /dev/null
@@ -1,221 +0,0 @@
-"use strict";
-
-/*
- *********************************************************************************
- *                                                                               *
- *                                  WARNING                                      *
- *                                                                               *
- * If you adjust any of the constants here (slice limit, number of keys, etc.)   *
- * make sure to update the JSON schema at:                                       *
- * https://github.com/mozilla-services/mozilla-pipeline-schemas/blob/master/     *
- * telemetry/main.schema.json                                                    *
- *                                                                               *
- * Otherwise, pings may be dropped by the telemetry backend!                     *
- *                                                                               *
- ********************************************************************************/
-
-const { GCTelemetry } = ChromeUtils.import(
-  "resource://gre/modules/GCTelemetry.jsm"
-);
-
-function check(entries) {
-  const FIELDS = ["random", "worst"];
-
-  // Check that all FIELDS are in |entries|.
-  for (let f of FIELDS) {
-    ok(f in entries, `${f} found in entries`);
-  }
-
-  // Check that only FIELDS are in |entries|.
-  for (let k of Object.keys(entries)) {
-    ok(FIELDS.includes(k), `${k} found in FIELDS`);
-  }
-
-  for (let f of FIELDS) {
-    ok(Array.isArray(entries[f]), "have an array of GCs");
-
-    ok(entries[f].length <= 2, "not too many GCs");
-
-    for (let gc of entries[f]) {
-      isnot(gc, null, "GC is non-null");
-
-      ok(Object.keys(gc).length <= 24, "number of keys in GC is not too large");
-
-      // Sanity check the GC data.
-      ok("status" in gc, "status field present");
-      is(gc.status, "completed", "status field correct");
-      ok("total_time" in gc, "total_time field present");
-      ok("max_pause" in gc, "max_pause field present");
-
-      ok("slices_list" in gc, "slices_list field present");
-      ok(Array.isArray(gc.slices_list), "slices_list is an array");
-      ok(gc.slices_list.length > 0, "slices_list array non-empty");
-      ok(gc.slices_list.length <= 4, "slices_list array is not too long");
-
-      ok("totals" in gc, "totals field present");
-      is(typeof gc.totals, "object", "totals is an object");
-      ok(Object.keys(gc.totals).length <= 65, "totals array is not too long");
-
-      // Make sure we don't skip any big objects.
-      for (let key in gc) {
-        if (key != "slices_list" && key != "totals") {
-          isnot(
-            typeof gc[key],
-            "object",
-            `${key} property should be primitive`
-          );
-        }
-      }
-
-      let phases = new Set();
-
-      for (let slice of gc.slices_list) {
-        ok(Object.keys(slice).length <= 12, "slice is not too large");
-
-        ok("pause" in slice, "pause field present in slice");
-        ok("reason" in slice, "reason field present in slice");
-        ok("times" in slice, "times field present in slice");
-
-        // Make sure we don't skip any big objects.
-        for (let key in slice) {
-          if (key != "times") {
-            isnot(
-              typeof slice[key],
-              "object",
-              `${key} property should be primitive`
-            );
-          }
-        }
-
-        ok(Object.keys(slice.times).length <= 65, "no more than 65 phases");
-
-        for (let phase in slice.times) {
-          phases.add(phase);
-          is(
-            typeof slice.times[phase],
-            "number",
-            `${phase} property should be a number`
-          );
-        }
-      }
-
-      let totals = gc.totals;
-      // Make sure we don't skip any big objects.
-      for (let phase in totals) {
-        is(
-          typeof totals[phase],
-          "number",
-          `${phase} property should be a number`
-        );
-      }
-
-      for (let phase of phases) {
-        ok(phase in totals, `${phase} is in totals`);
-      }
-    }
-  }
-}
-
-add_task(async function test() {
-  let multiprocess = Services.appinfo.browserTabsRemoteAutostart;
-
-  // Set these prefs to ensure that we get measurements.
-  await SpecialPowers.pushPrefEnv({
-    set: [["javascript.options.mem.notify", true]],
-  });
-
-  function runRemote(f) {
-    gBrowser.selectedBrowser.messageManager.loadFrameScript(
-      `data:,(${f})()`,
-      false
-    );
-  }
-
-  // These are available to frame scripts.
-  /* global addMessageListener:false, removeMessageListener: false */
-  function initScript() {
-    const { GCTelemetry } = ChromeUtils.import(
-      "resource://gre/modules/GCTelemetry.jsm"
-    );
-
-    /*
-     * Don't shut down GC telemetry if it was already running before the test!
-     * Note: We need to use a multiline comment here since this code is turned into a data: URI.
-     */
-    let shutdown = GCTelemetry.init();
-
-    function listener() {
-      removeMessageListener("GCTelemTest:Shutdown", listener);
-      if (shutdown) {
-        GCTelemetry.shutdown();
-      }
-    }
-    addMessageListener("GCTelemTest:Shutdown", listener);
-  }
-
-  if (multiprocess) {
-    runRemote(initScript);
-  }
-
-  // Don't shut down GC telemetry if it was already running before the test!
-  let shutdown = GCTelemetry.init();
-  registerCleanupFunction(() => {
-    if (shutdown) {
-      GCTelemetry.shutdown();
-    }
-
-    gBrowser.selectedBrowser.messageManager.sendAsyncMessage(
-      "GCTelemTest:Shutdown"
-    );
-  });
-
-  let localPromise = new Promise(resolve => {
-    function obs() {
-      Services.obs.removeObserver(obs, "garbage-collection-statistics");
-      resolve();
-    }
-    Services.obs.addObserver(obs, "garbage-collection-statistics");
-  });
-
-  let remotePromise;
-  if (multiprocess) {
-    remotePromise = new Promise(resolve => {
-      function obs() {
-        Services.ppmm.removeMessageListener("Telemetry:GCStatistics", obs);
-        resolve();
-      }
-      Services.ppmm.addMessageListener("Telemetry:GCStatistics", obs);
-    });
-  } else {
-    remotePromise = Promise.resolve();
-  }
-
-  // Make sure we have a GC to work with in both processes.
-  Cu.forceGC();
-  if (multiprocess) {
-    runRemote(() => Cu.forceGC());
-  }
-
-  info("Waiting for GCs");
-
-  await Promise.all([localPromise, remotePromise]);
-
-  let localEntries = GCTelemetry.entries("main", true);
-  let remoteEntries = multiprocess
-    ? GCTelemetry.entries("content", true)
-    : localEntries;
-
-  check(localEntries);
-  check(remoteEntries);
-
-  localEntries = GCTelemetry.entries("main", false);
-  remoteEntries = multiprocess
-    ? GCTelemetry.entries("content", false)
-    : localEntries;
-
-  is(localEntries.random.length, 0, "no random GCs after reset");
-  is(localEntries.worst.length, 0, "no worst GCs after reset");
-
-  is(remoteEntries.random.length, 0, "no random GCs after reset");
-  is(remoteEntries.worst.length, 0, "no worst GCs after reset");
-});
diff --git a/toolkit/components/telemetry/tests/unit/head.js b/toolkit/components/telemetry/tests/unit/head.js
index 3250a0391e..eb50b9bd88 100644
--- a/toolkit/components/telemetry/tests/unit/head.js
+++ b/toolkit/components/telemetry/tests/unit/head.js
@@ -552,7 +552,6 @@ if (runningInParent) {
   );
 
   // This gets imported via fakeNow();
-  /* global TelemetrySend */
   registerCleanupFunction(() => TelemetrySend.shutdown());
 }
 
diff --git a/toolkit/components/telemetry/tests/unit/test_SocketScalars.js b/toolkit/components/telemetry/tests/unit/test_SocketScalars.js
index aa7fc3e33d..1d7c0cebfd 100644
--- a/toolkit/components/telemetry/tests/unit/test_SocketScalars.js
+++ b/toolkit/components/telemetry/tests/unit/test_SocketScalars.js
@@ -37,7 +37,7 @@ add_task(async function() {
   do_get_profile(true);
   await TelemetryController.testSetup();
 
-  Services.netUtils.socketProcessTelemetryPing();
+  Services.io.socketProcessTelemetryPing();
 
   // Once scalars are set by the socket process, they don't immediately get
   // sent to the parent process. Wait for the Telemetry IPC Timer to trigger
diff --git a/toolkit/components/telemetry/tests/unit/test_TelemetryEnvironment.js b/toolkit/components/telemetry/tests/unit/test_TelemetryEnvironment.js
index be70bf74bd..6f83619ba3 100644
--- a/toolkit/components/telemetry/tests/unit/test_TelemetryEnvironment.js
+++ b/toolkit/components/telemetry/tests/unit/test_TelemetryEnvironment.js
@@ -167,11 +167,8 @@ var SysInfo = {
     if (name in this.overrides) {
       return this.overrides[name];
     }
-    try {
-      return this._genuine.getProperty(name);
-    } catch (ex) {
-      throw ex;
-    }
+
+    return this._genuine.getProperty(name);
   },
 
   getPropertyAsUint32(name) {
diff --git a/toolkit/components/telemetry/tests/unit/test_TelemetryGC.js b/toolkit/components/telemetry/tests/unit/test_TelemetryGC.js
deleted file mode 100644
index e3112cb57a..0000000000
--- a/toolkit/components/telemetry/tests/unit/test_TelemetryGC.js
+++ /dev/null
@@ -1,170 +0,0 @@
-/* Any copyright is dedicated to the Public Domain.
-   http://creativecommons.org/publicdomain/zero/1.0/
-*/
-
-"use strict";
-
-ChromeUtils.import("resource://gre/modules/GCTelemetry.jsm", this);
-
-function do_register_cleanup() {
-  GCTelemetry.shutdown();
-}
-
-/*
- * These tests are very basic, my goal was to add enough testing to support
- * a change made in Bug 1424760.  TODO Bug 1429635 for adding more extensive
- * tests and deleting this comment.
- */
-
-function run_test() {
-  // The limit on the number of fields in a GCMajor object.
-  const limit = 24;
-
-  // The number of fields that the make_gc() test function generates.
-  const make_gc_fields = 19;
-
-  // Test initialisation
-  Assert.ok(GCTelemetry.init(), "Initialize success");
-  Assert.ok(!GCTelemetry.init(), "Wont initialize twice");
-
-  // Test the basic success path.
-
-  // There are currently no entries
-  assert_num_entries(0, false);
-
-  // Add an entry
-  GCTelemetry.observeRaw(make_gc());
-  // Get it back.
-  assert_num_entries(1, false);
-  Assert.equal(make_gc_fields, Object.keys(get_entry()).length);
-  // "true" will cause the entry to be clared.
-  assert_num_entries(1, true);
-  // There are currently no entries.
-  assert_num_entries(0, false);
-
-  // Test too many fields
-  let my_big_gc = make_gc();
-  for (let i = 0; i < 100; i++) {
-    my_big_gc["new_property_" + i] = "Data";
-  }
-  GCTelemetry.observeRaw(my_big_gc);
-  // Assert that it was recorded but has only 7 fields.
-  Assert.equal(7, Object.keys(get_entry()).length);
-  assert_num_entries(1, true);
-  assert_num_entries(0, false);
-
-  let my_gc_exact = make_gc();
-  Assert.equal(make_gc_fields, Object.keys(my_gc_exact).length);
-
-  for (let i = 0; i < limit - make_gc_fields; i++) {
-    my_gc_exact["new_property_" + i] = "Data";
-  }
-  GCTelemetry.observeRaw(my_gc_exact);
-  // Assert that it was recorded has all the fields.
-  Assert.equal(limit, Object.keys(get_entry()).length);
-  assert_num_entries(1, true);
-  assert_num_entries(0, false);
-
-  // Exactly too many fields.
-  let my_gc_too_many = make_gc();
-  for (let i = 0; i < limit - make_gc_fields + 1; i++) {
-    my_gc_too_many["new_property_" + i] = "Data";
-  }
-  GCTelemetry.observeRaw(my_gc_too_many);
-  // Assert that it was recorded but has only 7 fields.
-  Assert.equal(7, Object.keys(get_entry()).length);
-  assert_num_entries(1, true);
-  assert_num_entries(0, false);
-}
-
-function assert_num_entries(expect, clear) {
-  let entries = GCTelemetry.entries("main", clear);
-  Assert.equal(expect, entries.worst.length, expect + " worst entries");
-  // Randomly sampled GCs are only recorded for content processes
-  Assert.equal(0, entries.random.length, expect + " random entries");
-}
-
-function get_entry() {
-  let entries = GCTelemetry.entries("main", false);
-  Assert.ok(entries, "Got entries object");
-  Assert.ok(entries.random, "Has random property");
-  Assert.ok(entries.worst, "Has worst property");
-  let entry = entries.worst[0];
-  Assert.ok(entry, "Got worst entry");
-  return entry;
-}
-
-/*
- * These events are not exactly well-formed, but good enough.  For example
- * there's no guantee that all the pause times add up to total time, or
- * that max_pause is correct.
- */
-function make_gc() {
-  // Timestamps are in milliseconds since startup. All the times here
-  // are wall-clock times, which may not be monotonically increasing.
-  let timestamp = Math.random() * 1000000;
-
-  let gc = {
-    status: "completed",
-    timestamp,
-    // All durations are in milliseconds.
-    max_pause: Math.random() * 95 + 5,
-    total_time: Math.random() * 500 + 500, // Sum of all slice times.
-    zones_collected: 9,
-    total_zones: 9,
-    total_compartments: 309,
-    minor_gcs: 44,
-    store_buffer_overflows: 19,
-    mmu_20ms: 0,
-    mmu_50ms: 0,
-    nonincremental_reason: "GCBytesTrigger",
-    allocated_bytes: 38853696, // in bytes
-    added_chunks: 54,
-    removed_chunks: 12,
-    slices: 15,
-    slice_number: 218, // The first slice number for this GC event.
-    slices_list: [
-      {
-        slice: 218, // The global index of this slice.
-        pause: Math.random() * 2 + 28,
-        reason: "SET_NEW_DOCUMENT",
-        initial_state: "NotActive",
-        final_state: "Mark",
-        budget: "10ms",
-        page_faults: 1,
-        start_timestamp: timestamp + Math.random() * 50000,
-        times: {
-          wait_background_thread: 0.012,
-          mark_discard_code: 2.845,
-          purge: 0.723,
-          mark: 9.831,
-          mark_roots: 0.102,
-          buffer_gray_roots: 3.095,
-          mark_cross_compartment_wrappers: 0.039,
-          mark_c_and_js_stacks: 0.005,
-          mark_runtime_wide_data: 2.313,
-          mark_embedding: 0.117,
-          mark_compartments: 2.27,
-          unmark: 1.063,
-          minor_gcs_to_evict_nursery: 8.701,
-        },
-      },
-    ],
-    totals: {
-      wait_background_thread: 0.012,
-      mark_discard_code: 2.845,
-      purge: 0.723,
-      mark: 9.831,
-      mark_roots: 0.102,
-      buffer_gray_roots: 3.095,
-      mark_cross_compartment_wrappers: 0.039,
-      mark_c_and_js_stacks: 0.005,
-      mark_runtime_wide_data: 2.313,
-      mark_embedding: 0.117,
-      mark_compartments: 2.27,
-      unmark: 1.063,
-      minor_gcs_to_evict_nursery: 8.701,
-    },
-  };
-  return gc;
-}
diff --git a/toolkit/components/telemetry/tests/unit/test_TelemetryHistograms.js b/toolkit/components/telemetry/tests/unit/test_TelemetryHistograms.js
index 911db0cbe7..b256e125f3 100644
--- a/toolkit/components/telemetry/tests/unit/test_TelemetryHistograms.js
+++ b/toolkit/components/telemetry/tests/unit/test_TelemetryHistograms.js
@@ -348,13 +348,6 @@ add_task(async function test_getSlowSQL() {
   Assert.ok("mainThread" in slow && "otherThreads" in slow);
 });
 
-add_task(async function test_getWebrtc() {
-  var webrtc = Telemetry.webrtcStats;
-  Assert.ok("IceCandidatesStats" in webrtc);
-  var icestats = webrtc.IceCandidatesStats;
-  Assert.ok("webrtc" in icestats);
-});
-
 // Check that telemetry doesn't record in private mode
 add_task(async function test_privateMode() {
   var h = Telemetry.getHistogramById("TELEMETRY_TEST_BOOLEAN");
diff --git a/toolkit/components/telemetry/tests/unit/test_TelemetrySession.js b/toolkit/components/telemetry/tests/unit/test_TelemetrySession.js
index 30a2ae3095..6d6c9fd21d 100644
--- a/toolkit/components/telemetry/tests/unit/test_TelemetrySession.js
+++ b/toolkit/components/telemetry/tests/unit/test_TelemetrySession.js
@@ -457,11 +457,6 @@ function checkPayload(payload, reason, successfulPings) {
     "mainThread" in payload.slowSQL && "otherThreads" in payload.slowSQL
   );
 
-  Assert.ok(
-    "IceCandidatesStats" in payload.webrtc &&
-      "webrtc" in payload.webrtc.IceCandidatesStats
-  );
-
   // Check keyed histogram payload.
 
   Assert.ok("keyedHistograms" in payload);
@@ -2012,7 +2007,6 @@ add_task(async function test_pingExtendedStats() {
     "fileIOReports",
     "lateWrites",
     "addonDetails",
-    "webrtc",
   ];
 
   if (AppConstants.platform == "android") {
diff --git a/toolkit/components/telemetry/tests/unit/xpcshell.ini b/toolkit/components/telemetry/tests/unit/xpcshell.ini
index ea014da12d..7afa5476c0 100644
--- a/toolkit/components/telemetry/tests/unit/xpcshell.ini
+++ b/toolkit/components/telemetry/tests/unit/xpcshell.ini
@@ -92,7 +92,6 @@ skip-if = os == "android" # Disabled due to crashes (see bug 1331366)
 skip-if = (os == "win" && processor == "aarch64") # bug 1530759
 [test_PingSender.js]
 skip-if = (os == "android") || (os == "linux" && bits == 32)
-[test_TelemetryGC.js]
 [test_TelemetryAndroidEnvironment.js]
 [test_TelemetryUtils.js]
 [test_UntrustedModulesPing.js]
diff --git a/toolkit/components/url-classifier/nsUrlClassifierPrefixSet.cpp b/toolkit/components/url-classifier/nsUrlClassifierPrefixSet.cpp
index 626575043f..61927d7427 100644
--- a/toolkit/components/url-classifier/nsUrlClassifierPrefixSet.cpp
+++ b/toolkit/components/url-classifier/nsUrlClassifierPrefixSet.cpp
@@ -538,7 +538,7 @@ nsresult nsUrlClassifierPrefixSet::WritePrefixes(
       totalDeltas += deltaLength;
       indexStarts.AppendElement(totalDeltas);
     }
-    indexStarts.RemoveElementAt(indexSize);  // we don't use the last element
+    indexStarts.RemoveLastElement();  // we don't use the last element
     MOZ_ASSERT(indexStarts.Length() == indexSize);
   }
 
diff --git a/toolkit/components/urlformatter/components.conf b/toolkit/components/urlformatter/components.conf
index 4ad714ed7c..7384ddb629 100644
--- a/toolkit/components/urlformatter/components.conf
+++ b/toolkit/components/urlformatter/components.conf
@@ -4,8 +4,10 @@
 
 Classes = [
     {
+        'js_name': 'urlFormatter',
         'cid': '{e6156350-2be8-11db-a98b-0800200c9a66}',
         'contract_ids': ['@mozilla.org/toolkit/URLFormatterService;1'],
+        'interfaces': ['nsIURLFormatter'],
         'jsm': 'resource://gre/modules/URLFormatter.jsm',
         'constructor': 'nsURLFormatterService',
     },
diff --git a/toolkit/components/xulstore/components.conf b/toolkit/components/xulstore/components.conf
index f74c60b32a..90d8d2ecaf 100644
--- a/toolkit/components/xulstore/components.conf
+++ b/toolkit/components/xulstore/components.conf
@@ -12,12 +12,21 @@ if defined('MOZ_NEW_XULSTORE'):
             'singleton': True,
             'constructor': 'mozilla::XULStore::GetService',
         },
+        {
+            'js_name': 'xulStore',
+            'cid': '{e8e12dba-b942-4c0d-aa21-2843cfc64529}',
+            'contract_ids': ['@mozilla.org/xul/js-xulstore;1'],
+            'jsm': 'resource://gre/modules/XULStore.jsm',
+            'constructor': 'getXULStore',
+        },
     ]
 else:
     Classes = [
         {
+            'js_name': 'xulStore',
             'cid': '{6f46b6f4-c8b1-4bd4-a4fa-9ebbed0753ea}',
             'contract_ids': ['@mozilla.org/xul/xulstore;1'],
+            'interfaces': ['nsIXULStore'],
             'jsm': 'resource://gre/modules/XULStore.jsm',
             'constructor': 'XULStore',
         },
diff --git a/toolkit/components/xulstore/new/XULStore.jsm b/toolkit/components/xulstore/new/XULStore.jsm
index 63299eed5e..84ef5d7de3 100644
--- a/toolkit/components/xulstore/new/XULStore.jsm
+++ b/toolkit/components/xulstore/new/XULStore.jsm
@@ -10,7 +10,7 @@
 // protocol.  It also implements the persist() method.  JS consumers should use
 // this module rather than accessing nsIXULStore directly.
 
-const EXPORTED_SYMBOLS = ["XULStore"];
+const EXPORTED_SYMBOLS = ["XULStore", "getXULStore"];
 
 // Services.xulStore loads this module and returns its `XULStore` symbol
 // when this implementation of XULStore is enabled, so using it here
@@ -99,3 +99,9 @@ class XULStoreEnumerator {
     }
   }
 }
+
+// Only here for the sake of component registration, which requires a
+// callable function.
+function getXULStore() {
+  return XULStore;
+}
diff --git a/toolkit/content/aboutAbout.xhtml b/toolkit/content/aboutAbout.xhtml
index 61ff1c45f3..156bcca0ff 100644
--- a/toolkit/content/aboutAbout.xhtml
+++ b/toolkit/content/aboutAbout.xhtml
@@ -7,6 +7,7 @@
 
 <html xmlns="http://www.w3.org/1999/xhtml">
 <head>
+  <meta http-equiv="Content-Security-Policy" content="default-src chrome:" />
   <title data-l10n-id="about-about-title"></title>
   <link rel="stylesheet" href="chrome://global/skin/in-content/info-pages.css" type="text/css"/>
   <link rel="localization" href="toolkit/about/aboutAbout.ftl"/>
diff --git a/toolkit/content/aboutNetworking.xhtml b/toolkit/content/aboutNetworking.xhtml
index dc3c51ae52..e620a25c37 100644
--- a/toolkit/content/aboutNetworking.xhtml
+++ b/toolkit/content/aboutNetworking.xhtml
@@ -8,6 +8,7 @@
 
 <html xmlns="http://www.w3.org/1999/xhtml">
     <head>
+        <meta http-equiv="Content-Security-Policy" content="default-src chrome:" />
         <title data-l10n-id="title"/>
         <link rel="stylesheet" href="chrome://mozapps/skin/aboutNetworking.css" type="text/css" />
         <script src="chrome://global/content/aboutNetworking.js" />
diff --git a/toolkit/content/aboutProfiles.xhtml b/toolkit/content/aboutProfiles.xhtml
index 7411c19ad1..8319831d1e 100644
--- a/toolkit/content/aboutProfiles.xhtml
+++ b/toolkit/content/aboutProfiles.xhtml
@@ -8,6 +8,7 @@
 
 <html xmlns="http://www.w3.org/1999/xhtml">
 <head>
+    <meta http-equiv="Content-Security-Policy" content="default-src chrome:" />
     <title data-l10n-id="profiles-title"></title>
     <link rel="icon" type="image/png" id="favicon" href="chrome://branding/content/icon32.png" />
     <link rel="stylesheet" href="chrome://mozapps/skin/aboutProfiles.css" type="text/css" />
diff --git a/toolkit/content/aboutServiceWorkers.xhtml b/toolkit/content/aboutServiceWorkers.xhtml
index 7ec8ef80b0..9aff19ecf2 100644
--- a/toolkit/content/aboutServiceWorkers.xhtml
+++ b/toolkit/content/aboutServiceWorkers.xhtml
@@ -10,6 +10,7 @@
 
 <html xmlns="http://www.w3.org/1999/xhtml">
     <head>
+        <meta http-equiv="Content-Security-Policy" content="default-src chrome:" />
         <title data-l10n-id="about-service-workers-title"></title>
         <link rel="stylesheet" href="chrome://global/skin/about.css" type="text/css" />
         <link rel="stylesheet" href="chrome://mozapps/skin/aboutServiceWorkers.css" type="text/css" />
diff --git a/toolkit/content/aboutSupport.xhtml b/toolkit/content/aboutSupport.xhtml
index d60bb9987f..2962aa91b5 100644
--- a/toolkit/content/aboutSupport.xhtml
+++ b/toolkit/content/aboutSupport.xhtml
@@ -11,6 +11,7 @@
 
 <html xmlns="http://www.w3.org/1999/xhtml">
   <head>
+    <meta http-equiv="Content-Security-Policy" content="default-src chrome:" />
     <title data-l10n-id="page-title"/>
 
     <link rel="icon" type="image/png" id="favicon"
diff --git a/toolkit/content/aboutTelemetry.xhtml b/toolkit/content/aboutTelemetry.xhtml
index fd46162611..452c1efc33 100644
--- a/toolkit/content/aboutTelemetry.xhtml
+++ b/toolkit/content/aboutTelemetry.xhtml
@@ -8,6 +8,7 @@
 
 <html xmlns="http://www.w3.org/1999/xhtml">
   <head>
+    <meta http-equiv="Content-Security-Policy" content="default-src chrome:" />
     <title data-l10n-id="about-telemetry-page-title"></title>
     <link rel="stylesheet" href="chrome://global/content/aboutTelemetry.css"
           type="text/css"/>
diff --git a/toolkit/content/aboutUrlClassifier.js b/toolkit/content/aboutUrlClassifier.js
index 79f6b78bb3..5e0bad4044 100644
--- a/toolkit/content/aboutUrlClassifier.js
+++ b/toolkit/content/aboutUrlClassifier.js
@@ -8,24 +8,19 @@ const UPDATE_BEGIN = "safebrowsing-update-begin";
 const UPDATE_FINISH = "safebrowsing-update-finished";
 const JSLOG_PREF = "browser.safebrowsing.debug";
 
-function unLoad() {
-  window.removeEventListener("unload", unLoad);
-
+window.onunload = function() {
   Search.uninit();
   Provider.uninit();
   Cache.uninit();
   Debug.uninit();
-}
-
-function onLoad() {
-  window.removeEventListener("load", onLoad);
-  window.addEventListener("unload", unLoad);
+};
 
+window.onload = function() {
   Search.init();
   Provider.init();
   Cache.init();
   Debug.init();
-}
+};
 
 /*
  * Search
diff --git a/toolkit/content/aboutUrlClassifier.xhtml b/toolkit/content/aboutUrlClassifier.xhtml
index 89aac0032c..f0eea6c71e 100644
--- a/toolkit/content/aboutUrlClassifier.xhtml
+++ b/toolkit/content/aboutUrlClassifier.xhtml
@@ -10,13 +10,14 @@
 
 <html xmlns="http://www.w3.org/1999/xhtml">
 <head>
+  <meta http-equiv="Content-Security-Policy" content="default-src chrome:" />
   <title data-l10n-id="url-classifier-title"></title>
   <link rel="stylesheet" href="chrome://global/content/aboutUrlClassifier.css" type="text/css"/>
   <link rel="localization" href="toolkit/about/url-classifier.ftl"/>
   <script src="chrome://global/content/aboutUrlClassifier.js"></script>
 </head>
 
-<body onload="onLoad()" class="wide-container">
+<body class="wide-container">
   <h1 data-l10n-id="url-classifier-title"></h1>
   <div id="search">
     <h2 class="major-section" data-l10n-id="url-classifier-search-title"></h2>
diff --git a/toolkit/content/browser-content.js b/toolkit/content/browser-content.js
index 90d6acf1b8..8c2b6a0994 100644
--- a/toolkit/content/browser-content.js
+++ b/toolkit/content/browser-content.js
@@ -4,7 +4,6 @@
 
 /* eslint-env mozilla/frame-script */
 /* eslint no-unused-vars: ["error", {args: "none"}] */
-/* global sendAsyncMessage */
 
 var { Services } = ChromeUtils.import("resource://gre/modules/Services.jsm");
 var { XPCOMUtils } = ChromeUtils.import(
diff --git a/toolkit/content/contentAreaUtils.js b/toolkit/content/contentAreaUtils.js
index 38783a28ed..c43ec92b6a 100644
--- a/toolkit/content/contentAreaUtils.js
+++ b/toolkit/content/contentAreaUtils.js
@@ -1396,7 +1396,7 @@ function getCharsetforSave(aDocument) {
  * WARNING: Please note that openURL() does not perform any content security checks!!!
  */
 function openURL(aURL) {
-  var uri = makeURI(aURL);
+  var uri = aURL instanceof Ci.nsIURI ? aURL : makeURI(aURL);
 
   var protocolSvc = Cc[
     "@mozilla.org/uriloader/external-protocol-service;1"
diff --git a/toolkit/content/directionDetector.html b/toolkit/content/directionDetector.html
deleted file mode 100644
index 5e91ba7f57..0000000000
--- a/toolkit/content/directionDetector.html
+++ /dev/null
@@ -1,13 +0,0 @@
-<!-- This Source Code Form is subject to the terms of the Mozilla Public
-   - License, v. 2.0. If a copy of the MPL was not distributed with this
-   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
-
-<!DOCTYPE html>
-<html>
-  <head>
-    <link rel="stylesheet" type="text/css" href="chrome://global/locale/intl.css">
-  </head>
-  <body>
-    <window id="target" style="display: none;"></window>
-  </body>
-</html>
diff --git a/toolkit/content/jar.mn b/toolkit/content/jar.mn
index 6859437d90..5452bff0b8 100644
--- a/toolkit/content/jar.mn
+++ b/toolkit/content/jar.mn
@@ -31,9 +31,9 @@ toolkit.jar:
    content/global/aboutUrlClassifier.js
    content/global/aboutUrlClassifier.xhtml
    content/global/aboutUrlClassifier.css
-   content/global/directionDetector.html
    content/global/plugins.html
    content/global/plugins.css
+   content/global/plugins.js
    content/global/browser-child.js
    content/global/browser-content.js
 *   content/global/buildconfig.html
diff --git a/toolkit/content/license.html b/toolkit/content/license.html
index 5074f33730..a766e2572e 100644
--- a/toolkit/content/license.html
+++ b/toolkit/content/license.html
@@ -157,7 +157,6 @@
       <li><a href="about:license#raven-js">Raven.js License</a></li>
       <li><a href="about:license#react">React License</a></li>
       <li><a href="about:license#react-mit">React MIT License</a></li>
-      <li><a href="about:license#react-intl">React Intl License</a></li>
       <li><a href="about:license#react-redux">React-Redux License</a></li>
       <li><a href="about:license#react-router">React Router License</a></li>
       <li><a href="about:license#xdg">Red Hat xdg_user_dir_lookup License</a></li>
@@ -5685,42 +5684,6 @@ SOFTWARE.
 
   <hr>
 
-    <h1><a id="react-intl"></a>React Intl License</h1>
-
-    <p>This license applies to the files
-    <code>browser/components/newtab/vendor/react-intl.js</code>.</p>
-<pre>
-Copyright 2014 Yahoo Inc.
-All rights reserved.
-
-Redistribution and use in source and binary forms, with or without
-modification, are permitted provided that the following conditions are met:
-
-    * Redistributions of source code must retain the above copyright
-      notice, this list of conditions and the following disclaimer.
-
-    * Redistributions in binary form must reproduce the above copyright
-      notice, this list of conditions and the following disclaimer in the
-      documentation and/or other materials provided with the distribution.
-
-    * Neither the name of the Yahoo Inc. nor the
-      names of its contributors may be used to endorse or promote products
-      derived from this software without specific prior written permission.
-
-THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
-ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
-WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
-DISCLAIMED. IN NO EVENT SHALL YAHOO! INC. BE LIABLE FOR ANY
-DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
-(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
-LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
-ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
-SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-</pre>
-
-    <hr>
-
     <h1><a id="react-redux"></a>React-Redux License</h1>
 
     <p>This license applies to the files
diff --git a/toolkit/content/moz.build b/toolkit/content/moz.build
index 103931fcd5..931b4f5819 100644
--- a/toolkit/content/moz.build
+++ b/toolkit/content/moz.build
@@ -258,9 +258,6 @@ with Files('contentAreaUtils.js'):
 with Files('*picker*'):
     BUG_COMPONENT = ('Toolkit', 'XUL Widgets')
 
-with Files('direction*'):
-    BUG_COMPONENT = ('Toolkit', 'XUL Widgets')
-
 with Files('edit*'):
     BUG_COMPONENT = ('Toolkit', 'XUL Widgets')
 
diff --git a/toolkit/content/plugins.html b/toolkit/content/plugins.html
index 6bb2aa0ac5..1e3dd0deaa 100644
--- a/toolkit/content/plugins.html
+++ b/toolkit/content/plugins.html
@@ -6,216 +6,15 @@
 
 <html>
 <head>
+<meta http-equiv="Content-Security-Policy" content="default-src chrome: resource:" />
 <title data-l10n-id="title-label"></title>
-<script>
-  "use strict";
-  const {Services} = ChromeUtils.import("resource://gre/modules/Services.jsm");
-</script>
 <link rel="stylesheet" type="text/css" href="chrome://global/content/plugins.css">
 <link rel="stylesheet" type="text/css" href="chrome://global/skin/plugins.css">
 <link rel="localization" href="toolkit/about/aboutPlugins.ftl"/>
 </head>
 <body>
 <div id="outside">
-<script>
-  /* eslint-env mozilla/frame-script */
-
-  "use strict";
-
-  function setDirection() {
-    var frame = document.getElementById("directionDetector");
-    var direction = frame.contentDocument
-                         .defaultView
-                         .window
-                         .getComputedStyle(frame.contentDocument.getElementById("target"))
-                         .getPropertyValue("direction");
-    document.body.removeChild(frame);
-    document.dir = direction;
-  }
-
-  function setupDirection() {
-    var frame = document.createElement("iframe");
-    frame.setAttribute("id", "directionDetector");
-    frame.setAttribute("src", "chrome://global/content/directionDetector.html");
-    frame.setAttribute("width", "0");
-    frame.setAttribute("height", "0");
-    frame.setAttribute("style", "visibility: hidden;");
-    frame.setAttribute("onload", "setDirection();");
-    document.body.appendChild(frame);
-  }
-  setupDirection();
-
-  /* JavaScript to enumerate and display all installed plug-ins
-
-   * First, refresh plugins in case anything has been changed recently in
-   * prefs: (The "false" argument tells refresh not to reload or activate
-   * any plug-ins that would be active otherwise.  In contrast, one would
-   * use "true" in the case of ASD instead of restarting)
-   */
-  navigator.plugins.refresh(false);
-
-  RPMAddMessageListener("PluginList", function({ data: aPlugins }) {
-    var fragment = document.createDocumentFragment();
-
-    // "Installed plugins"
-    var id, label;
-    if (aPlugins.length > 0) {
-      id = "plugs";
-      label = "installed-plugins-label";
-    } else {
-      id = "noplugs";
-      label = "no-plugins-are-installed-label";
-    }
-    var enabledplugins = document.createElement("h1");
-    enabledplugins.setAttribute("id", id);
-    document.l10n.setAttributes(enabledplugins, label);
-    fragment.appendChild(enabledplugins);
-
-    var deprecation = document.createElement("p");
-    var deprecationLink = document.createElement("a");
-    let deprecationLink_href = Services.urlFormatter.formatURLPref("app.support.baseURL") + "npapi";
-    deprecationLink.setAttribute("data-l10n-name", "deprecation-link");
-    deprecationLink.setAttribute("href", deprecationLink_href);
-    deprecation.appendChild(deprecationLink);
-    deprecation.setAttribute("class", "notice");
-    document.l10n.setAttributes(deprecation, "deprecation-description");
-    fragment.appendChild(deprecation);
-
-    var stateNames = {};
-    ["STATE_SOFTBLOCKED",
-     "STATE_BLOCKED",
-     "STATE_OUTDATED",
-     "STATE_VULNERABLE_UPDATE_AVAILABLE",
-     "STATE_VULNERABLE_NO_UPDATE"].forEach(function(label) {
-      stateNames[Ci.nsIBlocklistService[label]] = label;
-    });
-
-    for (var i = 0; i < aPlugins.length; i++) {
-      var plugin = aPlugins[i];
-      if (plugin) {
-        // "Shockwave Flash"
-        var plugname = document.createElement("h2");
-        plugname.setAttribute("class", "plugname");
-        plugname.appendChild(document.createTextNode(plugin.name));
-        fragment.appendChild(plugname);
-
-        var dl = document.createElement("dl");
-        fragment.appendChild(dl);
-
-        // "File: Flash Player.plugin"
-        var fileDd = document.createElement("dd");
-        var file = document.createElement("span");
-        file.setAttribute("data-l10n-name", "file");
-        file.setAttribute("class", "label");
-        fileDd.appendChild(file);
-        document.l10n.setAttributes(fileDd, "file-dd", { pluginLibraries: plugin.pluginLibraries[0] });
-        dl.appendChild(fileDd);
-
-        // "Path: /usr/lib/mozilla/plugins/libtotem-cone-plugin.so"
-        var pathDd = document.createElement("dd");
-        var path = document.createElement("span");
-        path.setAttribute("data-l10n-name", "path");
-        path.setAttribute("class", "label");
-        pathDd.appendChild(path);
-        document.l10n.setAttributes(pathDd, "path-dd", { pluginFullPath: plugin.pluginFullpath[0] });
-        dl.appendChild(pathDd);
-
-        // "Version: "
-        var versionDd = document.createElement("dd");
-        var version = document.createElement("span");
-        version.setAttribute("data-l10n-name", "version");
-        version.setAttribute("class", "label");
-        versionDd.appendChild(version);
-        document.l10n.setAttributes(versionDd, "version-dd", { version: plugin.version });
-        dl.appendChild(versionDd);
-
-        // "State: "
-        var stateDd = document.createElement("dd");
-        var state = document.createElement("span");
-        state.setAttribute("data-l10n-name", "state");
-        state.setAttribute("label", "state");
-        stateDd.appendChild(state);
-        if (plugin.isActive) {
-          if (plugin.blocklistState in stateNames) {
-            document.l10n.setAttributes(stateDd, "state-dd-enabled-block-list-state", { blockListState: stateNames[plugin.blocklistState] });
-          } else {
-            document.l10n.setAttributes(stateDd, "state-dd-enabled");
-          }
-        } else if (plugin.blocklistState in stateNames) {
-            document.l10n.setAttributes(stateDd, "state-dd-disabled-block-list-state", { blockListState: stateNames[plugin.blocklistState] });
-        } else {
-          document.l10n.setAttributes(stateDd, "state-dd-disabled");
-        }
-        dl.appendChild(stateDd);
-
-        // Plugin Description
-        var descDd = document.createElement("dd");
-        descDd.appendChild(document.createTextNode(plugin.description));
-        dl.appendChild(descDd);
-
-        // MIME Type table
-        var mimetypeTable = document.createElement("table");
-        mimetypeTable.setAttribute("border", "1");
-        mimetypeTable.setAttribute("class", "contenttable");
-        fragment.appendChild(mimetypeTable);
-
-        var thead = document.createElement("thead");
-        mimetypeTable.appendChild(thead);
-        var tr = document.createElement("tr");
-        thead.appendChild(tr);
-
-        // "MIME Type" column header
-        var typeTh = document.createElement("th");
-        typeTh.setAttribute("class", "type");
-        document.l10n.setAttributes(typeTh, "mime-type-label");
-        tr.appendChild(typeTh);
-
-        // "Description" column header
-        var descTh = document.createElement("th");
-        descTh.setAttribute("class", "desc");
-        document.l10n.setAttributes(descTh, "description-label");
-        tr.appendChild(descTh);
-
-        // "Suffixes" column header
-        var suffixesTh = document.createElement("th");
-        suffixesTh.setAttribute("class", "suff");
-        document.l10n.setAttributes(suffixesTh, "suffixes-label");
-        tr.appendChild(suffixesTh);
-
-        var tbody = document.createElement("tbody");
-        mimetypeTable.appendChild(tbody);
-
-        var mimeTypes = plugin.pluginMimeTypes;
-        for (var j = 0; j < mimeTypes.length; j++) {
-          var mimetype = mimeTypes[j];
-          if (mimetype) {
-            var mimetypeRow = document.createElement("tr");
-            tbody.appendChild(mimetypeRow);
-
-            // "application/x-shockwave-flash"
-            var typename = document.createElement("td");
-            typename.appendChild(document.createTextNode(mimetype.type));
-            mimetypeRow.appendChild(typename);
-
-            // "Shockwave Flash"
-            var description = document.createElement("td");
-            description.appendChild(document.createTextNode(mimetype.description));
-            mimetypeRow.appendChild(description);
-
-            // "swf"
-            var suffixes = document.createElement("td");
-            suffixes.appendChild(document.createTextNode(mimetype.suffixes));
-            mimetypeRow.appendChild(suffixes);
-          }
-        }
-      }
-    }
-
-    document.getElementById("outside").appendChild(fragment);
-  });
-
-  RPMSendAsyncMessage("RequestPlugins");
-</script>
+<script type="application/javascript" src="chrome://global/content/plugins.js"></script>
 </div>
 </body>
 </html>
diff --git a/toolkit/content/plugins.js b/toolkit/content/plugins.js
new file mode 100644
index 0000000000..73c31f151b
--- /dev/null
+++ b/toolkit/content/plugins.js
@@ -0,0 +1,199 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/* eslint-env mozilla/frame-script */
+
+"use strict";
+
+const { Services } = ChromeUtils.import("resource://gre/modules/Services.jsm");
+
+/* JavaScript to enumerate and display all installed plug-ins
+
+ * First, refresh plugins in case anything has been changed recently in
+ * prefs: (The "false" argument tells refresh not to reload or activate
+ * any plug-ins that would be active otherwise.  In contrast, one would
+ * use "true" in the case of ASD instead of restarting)
+ */
+navigator.plugins.refresh(false);
+
+RPMAddMessageListener("PluginList", function({ data: aPlugins }) {
+  var fragment = document.createDocumentFragment();
+
+  // "Installed plugins"
+  var id, label;
+  if (aPlugins.length > 0) {
+    id = "plugs";
+    label = "installed-plugins-label";
+  } else {
+    id = "noplugs";
+    label = "no-plugins-are-installed-label";
+  }
+  var enabledplugins = document.createElement("h1");
+  enabledplugins.setAttribute("id", id);
+  document.l10n.setAttributes(enabledplugins, label);
+  fragment.appendChild(enabledplugins);
+
+  var deprecation = document.createElement("p");
+  var deprecationLink = document.createElement("a");
+  let deprecationLink_href =
+    Services.urlFormatter.formatURLPref("app.support.baseURL") + "npapi";
+  deprecationLink.setAttribute("data-l10n-name", "deprecation-link");
+  deprecationLink.setAttribute("href", deprecationLink_href);
+  deprecation.appendChild(deprecationLink);
+  deprecation.setAttribute("class", "notice");
+  document.l10n.setAttributes(deprecation, "deprecation-description");
+  fragment.appendChild(deprecation);
+
+  var stateNames = {};
+  [
+    "STATE_SOFTBLOCKED",
+    "STATE_BLOCKED",
+    "STATE_OUTDATED",
+    "STATE_VULNERABLE_UPDATE_AVAILABLE",
+    "STATE_VULNERABLE_NO_UPDATE",
+  ].forEach(function(label) {
+    stateNames[Ci.nsIBlocklistService[label]] = label;
+  });
+
+  for (var i = 0; i < aPlugins.length; i++) {
+    var plugin = aPlugins[i];
+    if (plugin) {
+      // "Shockwave Flash"
+      var plugname = document.createElement("h2");
+      plugname.setAttribute("class", "plugname");
+      plugname.appendChild(document.createTextNode(plugin.name));
+      fragment.appendChild(plugname);
+
+      var dl = document.createElement("dl");
+      fragment.appendChild(dl);
+
+      // "File: Flash Player.plugin"
+      var fileDd = document.createElement("dd");
+      var file = document.createElement("span");
+      file.setAttribute("data-l10n-name", "file");
+      file.setAttribute("class", "label");
+      fileDd.appendChild(file);
+      document.l10n.setAttributes(fileDd, "file-dd", {
+        pluginLibraries: plugin.pluginLibraries[0],
+      });
+      dl.appendChild(fileDd);
+
+      // "Path: /usr/lib/mozilla/plugins/libtotem-cone-plugin.so"
+      var pathDd = document.createElement("dd");
+      var path = document.createElement("span");
+      path.setAttribute("data-l10n-name", "path");
+      path.setAttribute("class", "label");
+      pathDd.appendChild(path);
+      document.l10n.setAttributes(pathDd, "path-dd", {
+        pluginFullPath: plugin.pluginFullpath[0],
+      });
+      dl.appendChild(pathDd);
+
+      // "Version: "
+      var versionDd = document.createElement("dd");
+      var version = document.createElement("span");
+      version.setAttribute("data-l10n-name", "version");
+      version.setAttribute("class", "label");
+      versionDd.appendChild(version);
+      document.l10n.setAttributes(versionDd, "version-dd", {
+        version: plugin.version,
+      });
+      dl.appendChild(versionDd);
+
+      // "State: "
+      var stateDd = document.createElement("dd");
+      var state = document.createElement("span");
+      state.setAttribute("data-l10n-name", "state");
+      state.setAttribute("label", "state");
+      stateDd.appendChild(state);
+      if (plugin.isActive) {
+        if (plugin.blocklistState in stateNames) {
+          document.l10n.setAttributes(
+            stateDd,
+            "state-dd-enabled-block-list-state",
+            { blockListState: stateNames[plugin.blocklistState] }
+          );
+        } else {
+          document.l10n.setAttributes(stateDd, "state-dd-enabled");
+        }
+      } else if (plugin.blocklistState in stateNames) {
+        document.l10n.setAttributes(
+          stateDd,
+          "state-dd-disabled-block-list-state",
+          { blockListState: stateNames[plugin.blocklistState] }
+        );
+      } else {
+        document.l10n.setAttributes(stateDd, "state-dd-disabled");
+      }
+      dl.appendChild(stateDd);
+
+      // Plugin Description
+      var descDd = document.createElement("dd");
+      descDd.appendChild(document.createTextNode(plugin.description));
+      dl.appendChild(descDd);
+
+      // MIME Type table
+      var mimetypeTable = document.createElement("table");
+      mimetypeTable.setAttribute("border", "1");
+      mimetypeTable.setAttribute("class", "contenttable");
+      fragment.appendChild(mimetypeTable);
+
+      var thead = document.createElement("thead");
+      mimetypeTable.appendChild(thead);
+      var tr = document.createElement("tr");
+      thead.appendChild(tr);
+
+      // "MIME Type" column header
+      var typeTh = document.createElement("th");
+      typeTh.setAttribute("class", "type");
+      document.l10n.setAttributes(typeTh, "mime-type-label");
+      tr.appendChild(typeTh);
+
+      // "Description" column header
+      var descTh = document.createElement("th");
+      descTh.setAttribute("class", "desc");
+      document.l10n.setAttributes(descTh, "description-label");
+      tr.appendChild(descTh);
+
+      // "Suffixes" column header
+      var suffixesTh = document.createElement("th");
+      suffixesTh.setAttribute("class", "suff");
+      document.l10n.setAttributes(suffixesTh, "suffixes-label");
+      tr.appendChild(suffixesTh);
+
+      var tbody = document.createElement("tbody");
+      mimetypeTable.appendChild(tbody);
+
+      var mimeTypes = plugin.pluginMimeTypes;
+      for (var j = 0; j < mimeTypes.length; j++) {
+        var mimetype = mimeTypes[j];
+        if (mimetype) {
+          var mimetypeRow = document.createElement("tr");
+          tbody.appendChild(mimetypeRow);
+
+          // "application/x-shockwave-flash"
+          var typename = document.createElement("td");
+          typename.appendChild(document.createTextNode(mimetype.type));
+          mimetypeRow.appendChild(typename);
+
+          // "Shockwave Flash"
+          var description = document.createElement("td");
+          description.appendChild(
+            document.createTextNode(mimetype.description)
+          );
+          mimetypeRow.appendChild(description);
+
+          // "swf"
+          var suffixes = document.createElement("td");
+          suffixes.appendChild(document.createTextNode(mimetype.suffixes));
+          mimetypeRow.appendChild(suffixes);
+        }
+      }
+    }
+  }
+
+  document.getElementById("outside").appendChild(fragment);
+});
+
+RPMSendAsyncMessage("RequestPlugins");
diff --git a/toolkit/crashreporter/content/crashes.xhtml b/toolkit/crashreporter/content/crashes.xhtml
index 4a4a334ac6..51653ae32a 100644
--- a/toolkit/crashreporter/content/crashes.xhtml
+++ b/toolkit/crashreporter/content/crashes.xhtml
@@ -6,6 +6,7 @@
 <!DOCTYPE html>
 <html xmlns="http://www.w3.org/1999/xhtml">
   <head>
+    <meta http-equiv="Content-Security-Policy" content="default-src chrome:" />
     <link rel="localization" href="crashreporter/aboutcrashes.ftl"/>
     <link rel="stylesheet" type="text/css" href="chrome://global/content/crashes.css"/>
     <link rel="stylesheet" media="screen, projection" type="text/css"
diff --git a/toolkit/library/moz.build b/toolkit/library/moz.build
index 7ebecc7375..ca9c486436 100644
--- a/toolkit/library/moz.build
+++ b/toolkit/library/moz.build
@@ -365,6 +365,6 @@ if CONFIG['MOZ_WIDGET_TOOLKIT'] in ('cocoa', 'uikit'):
     libxul_list = 'XUL'
 else:
     libxul_list = '%sxul_%s' % (
-        CONFIG['DLL_PREFIX'], CONFIG['DLL_SUFFIX'].lstrip('.'))
+        CONFIG['DLL_PREFIX'], CONFIG['DLL_SUFFIX'].lstrip('.').replace('.','_'))
 GeneratedFile('buildid.cpp', script = 'gen_buildid.py',
               inputs=['!build/%s.list' % libxul_list])
diff --git a/toolkit/modules/Services.jsm b/toolkit/modules/Services.jsm
index 3597dfde18..9eb47cd456 100644
--- a/toolkit/modules/Services.jsm
+++ b/toolkit/modules/Services.jsm
@@ -2,166 +2,6 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-/* eslint mozilla/use-services:off */
-
 var EXPORTED_SYMBOLS = ["Services"];
 
-const { AppConstants } = ChromeUtils.import(
-  "resource://gre/modules/AppConstants.jsm"
-);
-const { XPCOMUtils } = ChromeUtils.import(
-  "resource://gre/modules/XPCOMUtils.jsm"
-);
-
-var Services = {};
-
-/**
- * WARNING: If you add a getter that isn't in the initTable, please update the
- * eslint rule in /tools/lint/eslint/eslint-plugin-mozilla/lib/rules/use-services.js
- */
-
-XPCOMUtils.defineLazyGetter(Services, "prefs", function() {
-  return Cc["@mozilla.org/preferences-service;1"]
-    .getService(Ci.nsIPrefService)
-    .QueryInterface(Ci.nsIPrefBranch);
-});
-
-XPCOMUtils.defineLazyGetter(Services, "appinfo", function() {
-  let appinfo = Cc["@mozilla.org/xre/app-info;1"].getService(Ci.nsIXULRuntime);
-  try {
-    appinfo.QueryInterface(Ci.nsIXULAppInfo);
-  } catch (ex) {
-    // Not all applications implement nsIXULAppInfo (e.g. xpcshell doesn't).
-    if (
-      !(ex instanceof Components.Exception) ||
-      ex.result != Cr.NS_NOINTERFACE
-    ) {
-      throw ex;
-    }
-  }
-  return appinfo;
-});
-
-XPCOMUtils.defineLazyGetter(Services, "dirsvc", function() {
-  return Cc["@mozilla.org/file/directory_service;1"]
-    .getService(Ci.nsIDirectoryService)
-    .QueryInterface(Ci.nsIProperties);
-});
-
-if (AppConstants.MOZ_CRASHREPORTER) {
-  XPCOMUtils.defineLazyGetter(Services, "crashmanager", () => {
-    let ns = {};
-    ChromeUtils.import("resource://gre/modules/CrashManager.jsm", ns);
-
-    return ns.CrashManager.Singleton;
-  });
-}
-
-XPCOMUtils.defineLazyGetter(Services, "io", () => {
-  return Cc["@mozilla.org/network/io-service;1"]
-    .getService(Ci.nsIIOService)
-    .QueryInterface(Ci.nsISpeculativeConnect);
-});
-
-var initTable = {
-  appShell: ["@mozilla.org/appshell/appShellService;1", "nsIAppShellService"],
-  cache2: [
-    "@mozilla.org/netwerk/cache-storage-service;1",
-    "nsICacheStorageService",
-  ],
-  catMan: ["@mozilla.org/categorymanager;1", "nsICategoryManager"],
-  clearData: ["@mozilla.org/clear-data-service;1", "nsIClearDataService"],
-  cpmm: ["@mozilla.org/childprocessmessagemanager;1", "nsIMessageSender"],
-  console: ["@mozilla.org/consoleservice;1", "nsIConsoleService"],
-  cookies: ["@mozilla.org/cookiemanager;1", "nsICookieManager"],
-  droppedLinkHandler: [
-    "@mozilla.org/content/dropped-link-handler;1",
-    "nsIDroppedLinkHandler",
-  ],
-  els: ["@mozilla.org/eventlistenerservice;1", "nsIEventListenerService"],
-  eTLD: [
-    "@mozilla.org/network/effective-tld-service;1",
-    "nsIEffectiveTLDService",
-  ],
-  intl: ["@mozilla.org/mozintl;1", "mozIMozIntl"],
-  locale: ["@mozilla.org/intl/localeservice;1", "mozILocaleService"],
-  logins: ["@mozilla.org/login-manager;1", "nsILoginManager"],
-  mm: ["@mozilla.org/globalmessagemanager;1", "nsISupports"],
-  obs: ["@mozilla.org/observer-service;1", "nsIObserverService"],
-  perms: ["@mozilla.org/permissionmanager;1", "nsIPermissionManager"],
-  ppmm: ["@mozilla.org/parentprocessmessagemanager;1", "nsISupports"],
-  prompt: ["@mozilla.org/embedcomp/prompt-service;1", "nsIPromptService"],
-  scriptloader: [
-    "@mozilla.org/moz/jssubscript-loader;1",
-    "mozIJSSubScriptLoader",
-  ],
-  scriptSecurityManager: [
-    "@mozilla.org/scriptsecuritymanager;1",
-    "nsIScriptSecurityManager",
-  ],
-  storage: ["@mozilla.org/storage/service;1", "mozIStorageService"],
-  domStorageManager: [
-    "@mozilla.org/dom/localStorage-manager;1",
-    "nsIDOMStorageManager",
-  ],
-  lsm: ["@mozilla.org/dom/localStorage-manager;1", "nsILocalStorageManager"],
-  search: ["@mozilla.org/browser/search-service;1", "nsISearchService"],
-  strings: ["@mozilla.org/intl/stringbundle;1", "nsIStringBundleService"],
-  telemetry: ["@mozilla.org/base/telemetry;1", "nsITelemetry"],
-  textToSubURI: ["@mozilla.org/intl/texttosuburi;1", "nsITextToSubURI"],
-  tm: ["@mozilla.org/thread-manager;1", "nsIThreadManager"],
-  urlFormatter: [
-    "@mozilla.org/toolkit/URLFormatterService;1",
-    "nsIURLFormatter",
-  ],
-  vc: ["@mozilla.org/xpcom/version-comparator;1", "nsIVersionComparator"],
-  wm: ["@mozilla.org/appshell/window-mediator;1", "nsIWindowMediator"],
-  ww: ["@mozilla.org/embedcomp/window-watcher;1", "nsIWindowWatcher"],
-  startup: ["@mozilla.org/toolkit/app-startup;1", "nsIAppStartup"],
-  sysinfo: ["@mozilla.org/system-info;1", "nsIPropertyBag2"],
-  clipboard: ["@mozilla.org/widget/clipboard;1", "nsIClipboard"],
-  DOMRequest: [
-    "@mozilla.org/dom/dom-request-service;1",
-    "nsIDOMRequestService",
-  ],
-  focus: ["@mozilla.org/focus-manager;1", "nsIFocusManager"],
-  uriFixup: ["@mozilla.org/docshell/urifixup;1", "nsIURIFixup"],
-  blocklist: ["@mozilla.org/extensions/blocklist;1"],
-  netUtils: ["@mozilla.org/network/util;1", "nsINetUtil"],
-  loadContextInfo: [
-    "@mozilla.org/load-context-info-factory;1",
-    "nsILoadContextInfoFactory",
-  ],
-  qms: ["@mozilla.org/dom/quota-manager-service;1", "nsIQuotaManagerService"],
-};
-
-if (AppConstants.platform == "android") {
-  initTable.androidBridge = [
-    "@mozilla.org/android/bridge;1",
-    "nsIAndroidBridge",
-  ];
-}
-if (AppConstants.MOZ_GECKO_PROFILER) {
-  initTable.profiler = ["@mozilla.org/tools/profiler;1", "nsIProfiler"];
-}
-if ("@mozilla.org/enterprisepolicies;1" in Cc) {
-  initTable.policies = [
-    "@mozilla.org/enterprisepolicies;1",
-    "nsIEnterprisePolicies",
-  ];
-}
-
-if (AppConstants.MOZ_NEW_XULSTORE) {
-  XPCOMUtils.defineLazyGetter(Services, "xulStore", () => {
-    const { XULStore } = ChromeUtils.import(
-      "resource://gre/modules/XULStore.jsm"
-    );
-    return XULStore;
-  });
-} else {
-  initTable.xulStore = ["@mozilla.org/xul/xulstore;1", "nsIXULStore"];
-}
-
-XPCOMUtils.defineLazyServiceGetters(Services, initTable);
-
-initTable = undefined;
+var Services = Cu.createServicesCache();
diff --git a/toolkit/moz.configure b/toolkit/moz.configure
index 54d2ff7378..c3f7d7aff9 100644
--- a/toolkit/moz.configure
+++ b/toolkit/moz.configure
@@ -76,10 +76,16 @@ set_define('MOZ_GECKO_PROFILER', gecko_profiler_define)
 # (for symbol table dumping).
 @depends(gecko_profiler, target)
 def gecko_profiler_parse_elf(value, target):
-    # Currently we only want to build this code on Android, in order to dump
-    # symbols from Android system libraries on the device. For other platforms
-    # there exist alternatives that don't require bloating up our binary size.
-    if value and target.os == 'Android':
+    # Currently we only want to build this code on Linux (including Android).
+    # For Android, this is in order to dump symbols from Android system, where
+    # on other platforms there exist alternatives that don't require bloating
+    # up our binary size. For Linux more generally, we use this in profile
+    # pre-symbolication support, since MozDescribeCodeAddress doesn't do
+    # anything useful on that platform. (Ideally, we would update
+    # MozDescribeCodeAddress to call into some Rust crates that parse ELF and
+    # DWARF data, but build system issues currently prevent Rust from being
+    # used in mozglue.)
+    if value and target.kernel == 'Linux':
         return True
 
 set_config('MOZ_GECKO_PROFILER_PARSE_ELF', gecko_profiler_parse_elf)
diff --git a/toolkit/mozapps/extensions/components.conf b/toolkit/mozapps/extensions/components.conf
index 94ba8f329f..8a61be29fe 100644
--- a/toolkit/mozapps/extensions/components.conf
+++ b/toolkit/mozapps/extensions/components.conf
@@ -4,6 +4,7 @@
 
 Classes = [
     {
+        'js_name': 'blocklist',
         'cid': '{66354bc9-7ed1-4692-ae1d-8da97d6b205e}',
         'contract_ids': ['@mozilla.org/extensions/blocklist;1'],
         'jsm': 'resource://gre/modules/addonManager.js',
diff --git a/toolkit/mozapps/extensions/internal/GMPProvider.jsm b/toolkit/mozapps/extensions/internal/GMPProvider.jsm
index 216b8a4b4c..ca203a890e 100644
--- a/toolkit/mozapps/extensions/internal/GMPProvider.jsm
+++ b/toolkit/mozapps/extensions/internal/GMPProvider.jsm
@@ -12,10 +12,8 @@ const { XPCOMUtils } = ChromeUtils.import(
 const { AddonManager, AddonManagerPrivate } = ChromeUtils.import(
   "resource://gre/modules/AddonManager.jsm"
 );
-/* globals AddonManagerPrivate*/
 const { Services } = ChromeUtils.import("resource://gre/modules/Services.jsm");
 const { OS } = ChromeUtils.import("resource://gre/modules/osfile.jsm");
-/* globals OS*/
 const { Log } = ChromeUtils.import("resource://gre/modules/Log.jsm");
 // These symbols are, unfortunately, accessed via the module global from
 // tests, and therefore cannot be lexical definitions.
diff --git a/toolkit/mozapps/extensions/internal/PluginProvider.jsm b/toolkit/mozapps/extensions/internal/PluginProvider.jsm
index 9941532e61..59977d3a54 100644
--- a/toolkit/mozapps/extensions/internal/PluginProvider.jsm
+++ b/toolkit/mozapps/extensions/internal/PluginProvider.jsm
@@ -11,7 +11,6 @@ var EXPORTED_SYMBOLS = [];
 const { AddonManager, AddonManagerPrivate } = ChromeUtils.import(
   "resource://gre/modules/AddonManager.jsm"
 );
-/* globals AddonManagerPrivate*/
 const { Services } = ChromeUtils.import("resource://gre/modules/Services.jsm");
 
 ChromeUtils.defineModuleGetter(
diff --git a/toolkit/mozapps/extensions/internal/ProductAddonChecker.jsm b/toolkit/mozapps/extensions/internal/ProductAddonChecker.jsm
index 90ca1f9492..f0950ad98a 100644
--- a/toolkit/mozapps/extensions/internal/ProductAddonChecker.jsm
+++ b/toolkit/mozapps/extensions/internal/ProductAddonChecker.jsm
@@ -31,15 +31,12 @@ const { OS } = ChromeUtils.import("resource://gre/modules/osfile.jsm");
 
 XPCOMUtils.defineLazyGlobalGetters(this, ["XMLHttpRequest"]);
 
-/* globals GMPPrefs */
 ChromeUtils.defineModuleGetter(
   this,
   "GMPPrefs",
   "resource://gre/modules/GMPUtils.jsm"
 );
 
-/* globals OS */
-
 ChromeUtils.defineModuleGetter(
   this,
   "UpdateUtils",
diff --git a/toolkit/mozapps/extensions/internal/XPIDatabase.jsm b/toolkit/mozapps/extensions/internal/XPIDatabase.jsm
index a3cc5613ac..ac6da5f19c 100644
--- a/toolkit/mozapps/extensions/internal/XPIDatabase.jsm
+++ b/toolkit/mozapps/extensions/internal/XPIDatabase.jsm
@@ -50,12 +50,7 @@ XPCOMUtils.defineLazyPreferenceGetter(
 const { nsIBlocklistService } = Ci;
 
 // These are injected from XPIProvider.jsm
-/* globals
- *         BOOTSTRAP_REASONS,
- *         DB_SCHEMA,
- *         XPIStates,
- *         migrateAddonLoader
- */
+/* globals BOOTSTRAP_REASONS, DB_SCHEMA, XPIStates, migrateAddonLoader */
 
 for (let sym of [
   "BOOTSTRAP_REASONS",
diff --git a/toolkit/mozapps/extensions/internal/XPIInstall.jsm b/toolkit/mozapps/extensions/internal/XPIInstall.jsm
index e772c41782..219437f2a2 100644
--- a/toolkit/mozapps/extensions/internal/XPIInstall.jsm
+++ b/toolkit/mozapps/extensions/internal/XPIInstall.jsm
@@ -23,8 +23,6 @@ var EXPORTED_SYMBOLS = [
   "verifyBundleSignedState",
 ];
 
-/* globals DownloadAddonInstall, LocalAddonInstall */
-
 const { Services } = ChromeUtils.import("resource://gre/modules/Services.jsm");
 const { XPCOMUtils } = ChromeUtils.import(
   "resource://gre/modules/XPCOMUtils.jsm"
diff --git a/toolkit/mozapps/extensions/internal/XPIProvider.jsm b/toolkit/mozapps/extensions/internal/XPIProvider.jsm
index 7a80a0adc5..e0dde31975 100644
--- a/toolkit/mozapps/extensions/internal/XPIProvider.jsm
+++ b/toolkit/mozapps/extensions/internal/XPIProvider.jsm
@@ -19,8 +19,6 @@
 
 var EXPORTED_SYMBOLS = ["XPIProvider", "XPIInternal"];
 
-/* globals WebExtensionPolicy */
-
 const { Services } = ChromeUtils.import("resource://gre/modules/Services.jsm");
 const { XPCOMUtils } = ChromeUtils.import(
   "resource://gre/modules/XPCOMUtils.jsm"
diff --git a/toolkit/mozapps/update/common/moz.build b/toolkit/mozapps/update/common/moz.build
index 92e88486c8..bd09a16b6e 100644
--- a/toolkit/mozapps/update/common/moz.build
+++ b/toolkit/mozapps/update/common/moz.build
@@ -53,9 +53,6 @@ SOURCES += [
     'updatecommon.cpp',
 ]
 
-if CONFIG['CC_TYPE'] == 'clang-cl':
-    AllowCompilerWarnings()  # workaround for bug 1090497
-
 LOCAL_INCLUDES += [
     '/other-licenses/nsis/Contrib/CityHash/cityhash',
 ]
diff --git a/toolkit/mozapps/update/tests/data/xpcshellUtilsAUS.js b/toolkit/mozapps/update/tests/data/xpcshellUtilsAUS.js
index d5ea178827..8473221a29 100644
--- a/toolkit/mozapps/update/tests/data/xpcshellUtilsAUS.js
+++ b/toolkit/mozapps/update/tests/data/xpcshellUtilsAUS.js
@@ -4222,6 +4222,7 @@ function start_httpserver() {
   gTestserver.registerPathHandler("/" + gHTTPHandlerPath, pathHandler);
   gTestserver.start(-1);
   let testserverPort = gTestserver.identity.primaryPort;
+  // eslint-disable-next-line no-global-assign
   gURLData = URL_HOST + ":" + testserverPort + "/";
   debugDump("http server port = " + testserverPort);
 }
diff --git a/toolkit/xre/components.conf b/toolkit/xre/components.conf
index 5d5a7191e1..35709ff0f1 100644
--- a/toolkit/xre/components.conf
+++ b/toolkit/xre/components.conf
@@ -9,13 +9,16 @@ else:
 
 Classes = [
     {
+        'js_name': 'appinfo',
         'cid': '{95d89e3e-a169-41a3-8e56-719978e15b12}',
         'contract_ids': [
             '@mozilla.org/xre/app-info;1',
             '@mozilla.org/xre/runtime;1',
         ] + crash_reporter,
+        'interfaces': ['nsIXULRuntime', 'nsIXULAppInfo'],
         'legacy_constructor': 'mozilla::AppInfoConstructor',
         'headers': ['nsAppRunner.h'],
+        'overridable': True,
     },
     {
         'cid': '{471f4944-1dd2-11b2-87ac-90be0a51d609}',
@@ -30,11 +33,14 @@ Classes = [
         'headers': ['/dom/webbrowserpersist/nsWebBrowserPersist.h'],
     },
     {
+        'js_name': 'ww',
         'cid': '{a21bfa01-f349-4394-a84c-8de5cf0737d0}',
         'contract_ids': ['@mozilla.org/embedcomp/window-watcher;1'],
+        'interfaces': ['nsIWindowWatcher'],
         'type': 'nsWindowWatcher',
         'headers': ['nsWindowWatcher.h'],
         'init_method': 'Init',
+        'overridable': True,
     },
     {
         'cid': '{5573967d-f6cf-4c63-8e0e-9ac06e04d62b}',
diff --git a/toolkit/xre/nsAppRunner.cpp b/toolkit/xre/nsAppRunner.cpp
index 041879837e..9c5e4407d4 100644
--- a/toolkit/xre/nsAppRunner.cpp
+++ b/toolkit/xre/nsAppRunner.cpp
@@ -13,7 +13,7 @@
 #include "mozilla/FilePreferences.h"
 #include "mozilla/ChaosMode.h"
 #include "mozilla/CmdLineAndEnvUtils.h"
-//#include "mozilla/IOInterposer.h"
+#include "mozilla/IOInterposer.h"
 #include "mozilla/Likely.h"
 #include "mozilla/MemoryChecking.h"
 #include "mozilla/Poison.h"
@@ -22,7 +22,6 @@
 #include "mozilla/ResultExtensions.h"
 #include "mozilla/ScopeExit.h"
 #include "mozilla/Services.h"
-//#include "mozilla/Telemetry.h"
 #include "mozilla/Utf8.h"
 #include "mozilla/intl/LocaleService.h"
 #include "mozilla/StaticPrefs_dom.h"
@@ -4082,7 +4081,7 @@ int XREMain::XRE_main(int argc, char* argv[], const BootstrapConfig& aConfig) {
   mAppData->sandboxPermissionsService = aConfig.sandboxPermissionsService;
 #endif
 
-  //mozilla::IOInterposerInit ioInterposerGuard;
+  mozilla::IOInterposerInit ioInterposerGuard;
 
 #if defined(XP_WIN)
   // Some COM settings are global to the process and must be set before any non-
diff --git a/tools/code-coverage/CodeCoverageHandler.cpp b/tools/code-coverage/CodeCoverageHandler.cpp
index 996d71a707..6984c6f01a 100644
--- a/tools/code-coverage/CodeCoverageHandler.cpp
+++ b/tools/code-coverage/CodeCoverageHandler.cpp
@@ -10,6 +10,7 @@
 #  include <signal.h>
 #  include <unistd.h>
 #endif
+#include "js/experimental/CodeCoverage.h"
 #include "mozilla/dom/ScriptSettings.h"  // for AutoJSAPI
 #include "mozilla/CodeCoverageHandler.h"
 #include "mozilla/ClearOnShutdown.h"
diff --git a/tools/lint/codespell.yml b/tools/lint/codespell.yml
index e8395dc818..e38f09c948 100644
--- a/tools/lint/codespell.yml
+++ b/tools/lint/codespell.yml
@@ -5,7 +5,6 @@ codespell:
         - browser/base/content/docs/
         - browser/branding/
         - browser/components/newtab/docs/
-        - browser/components/newtab/prerendered/locales/en-US/
         - browser/extensions/formautofill/locales/en-US/
         - browser/extensions/report-site-issue/locales/en-US/
         - browser/installer/windows/docs/
diff --git a/tools/lint/docs/coding-style/coding_style_cpp.rst b/tools/lint/docs/coding-style/coding_style_cpp.rst
index 9c42983e04..4c84eec193 100644
--- a/tools/lint/docs/coding-style/coding_style_cpp.rst
+++ b/tools/lint/docs/coding-style/coding_style_cpp.rst
@@ -291,8 +291,6 @@ files, use the following, specifying two-space indentation:
 
 .. code-block:: cpp
 
-   /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
-   /* vim: set ts=8 sts=2 et sw=2 tw=80: */
    /* This Source Code Form is subject to the terms of the Mozilla Public
     * License, v. 2.0. If a copy of the MPL was not distributed with this
     * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
diff --git a/tools/lint/eslint/eslint-plugin-mozilla/lib/configs/recommended.js b/tools/lint/eslint/eslint-plugin-mozilla/lib/configs/recommended.js
index 38a2e651d8..e8b6047c52 100644
--- a/tools/lint/eslint/eslint-plugin-mozilla/lib/configs/recommended.js
+++ b/tools/lint/eslint/eslint-plugin-mozilla/lib/configs/recommended.js
@@ -64,6 +64,9 @@ module.exports = {
       files: "**/*.jsm",
       rules: {
         "mozilla/mark-exported-symbols-as-used": "error",
+        // TODO: Bug 1575506 turn `builtinGlobals` on here.
+        // We can enable builtinGlobals for jsms due to their scopes.
+        "no-redeclare": ["error", { builtinGlobals: false }],
         // JSM modules are far easier to check for no-unused-vars on a global scope,
         // than our content files. Hence we turn that on here.
         "no-unused-vars": [
@@ -82,7 +85,11 @@ module.exports = {
   },
 
   // When adding items to this file please check for effects on sub-directories.
-  plugins: ["html", "no-unsanitized"],
+  plugins: [
+    "fetch-options",
+     "html",
+     "no-unsanitized",
+   ],
 
   // When adding items to this file please check for effects on all of toolkit
   // and browser
@@ -104,6 +111,10 @@ module.exports = {
     // Encourage the use of dot notation whenever possible.
     "dot-notation": "error",
 
+    // XXX This rule should be enabled, see Bug 1557040
+    // No credentials submitted with fetch calls
+    "fetch-options/no-fetch-credentials": "off",
+
     // XXX This rule line should be removed to enable it. See bug 1487642.
     // Enforce return statements in getters
     "getter-return": "off",
@@ -167,9 +178,18 @@ module.exports = {
     // Disallow unnecessary calls to .bind()
     "no-extra-bind": "error",
 
-    // XXX Bug 1487642 - decide if we want to enable this or not.
     // Disallow fallthrough of case statements
-    "no-fallthrough": "off",
+    "no-fallthrough": [
+      "error",
+      {
+        // The eslint rule doesn't allow for case-insensitive regex option.
+        // The following pattern allows for a dash between "fall through" as
+        // well as alternate spelling of "fall thru". The pattern also allows
+        // for an optional "s" at the end of "fall" ("falls through").
+        commentPattern:
+          "[Ff][Aa][Ll][Ll][Ss]?[\\s-]?([Tt][Hh][Rr][Oo][Uu][Gg][Hh]|[Tt][Hh][Rr][Uu])",
+      },
+    ],
 
     // Disallow assignments to native objects or read-only global variables
     "no-global-assign": "error",
@@ -199,9 +219,16 @@ module.exports = {
     // Use {} instead of new Object()
     "no-new-object": "error",
 
-    // Dissallow use of new wrappers
+    // Disallow use of new wrappers
     "no-new-wrappers": "error",
 
+    // We don't want this, see bug 1551829
+    "no-prototype-builtins": "off",
+
+    // Disable builtinGlobals for no-redeclare as this conflicts with our
+    // globals declarations especially for browser window.
+    "no-redeclare": ["error", { builtinGlobals: false }],
+
     // Disallow use of event global.
     "no-restricted-globals": ["error", "event"],
 
@@ -264,6 +291,10 @@ module.exports = {
     // Require object-literal shorthand with ES6 method syntax
     "object-shorthand": ["error", "always", { avoidQuotes: true }],
 
+    // This generates too many false positives that are not easy to work around,
+    // and false positives seem to be inherent in the rule.
+    "require-atomic-updates": "off",
+
     // XXX Bug 1487642 - decide if we want to enable this or not.
     // Require generator functions to contain yield
     "require-yield": "off",
diff --git a/tools/lint/eslint/eslint-plugin-mozilla/lib/globals.js b/tools/lint/eslint/eslint-plugin-mozilla/lib/globals.js
index b1f48c4cb7..7f1717ea7b 100644
--- a/tools/lint/eslint/eslint-plugin-mozilla/lib/globals.js
+++ b/tools/lint/eslint/eslint-plugin-mozilla/lib/globals.js
@@ -252,7 +252,10 @@ module.exports = {
         if (name === "script" && "src" in attribs) {
           scriptSrcs.push({
             src: attribs.src,
-            type: "type" in attribs ? attribs.type : "script",
+            type:
+              "type" in attribs && attribs.type == "module"
+                ? "module"
+                : "script",
           });
         }
       },
diff --git a/tools/lint/eslint/eslint-plugin-mozilla/manifest.tt b/tools/lint/eslint/eslint-plugin-mozilla/manifest.tt
index 4a5d37a4a5..a8bb059a6d 100644
--- a/tools/lint/eslint/eslint-plugin-mozilla/manifest.tt
+++ b/tools/lint/eslint/eslint-plugin-mozilla/manifest.tt
@@ -4,7 +4,7 @@
     "visibility": "public",
     "filename": "eslint-plugin-mozilla.tar.gz",
     "unpack": true,
-    "digest": "c43a5b4566aa75dac00e019772dc18d341c2efa3d7a9b469803d12383c3bffc2f8fcbbd5ec20b8311ea0c4849892251dd5bada53aea1237117c68c05c81c29fd",
-    "size": 4675325
+    "digest": "bb45acd4f16daf9c1ca2850a3e2a26405b560f8b991366e6651d62416d915bb10b23f52d22e075cc66564bae787580ece33ac90e4c7bcd41d3eacf03c03b5076",
+    "size": 4794148
   }
-]
+]
\ No newline at end of file
diff --git a/tools/lint/eslint/eslint-plugin-mozilla/package-lock.json b/tools/lint/eslint/eslint-plugin-mozilla/package-lock.json
index 81e8b5f44e..47eeec1e8c 100644
--- a/tools/lint/eslint/eslint-plugin-mozilla/package-lock.json
+++ b/tools/lint/eslint/eslint-plugin-mozilla/package-lock.json
@@ -1,6 +1,6 @@
 {
   "name": "eslint-plugin-mozilla",
-  "version": "2.0.0",
+  "version": "2.1.0",
   "lockfileVersion": 1,
   "requires": true,
   "dependencies": {
@@ -25,15 +25,15 @@
       }
     },
     "acorn": {
-      "version": "6.2.0",
-      "resolved": "https://registry.npmjs.org/acorn/-/acorn-6.2.0.tgz",
-      "integrity": "sha512-8oe72N3WPMjA+2zVG71Ia0nXZ8DpQH+QyyHO+p06jT8eg8FGG3FbcUIi8KziHlAfheJQZeoqbvq1mQSQHXKYLw==",
+      "version": "7.0.0",
+      "resolved": "https://registry.npmjs.org/acorn/-/acorn-7.0.0.tgz",
+      "integrity": "sha512-PaF/MduxijYYt7unVGRuds1vBC9bFxbNf+VWqhOClfdgy7RlVkQqt610ig1/yxTgsDIfW1cWDel5EBbOy3jdtQ==",
       "dev": true
     },
     "acorn-jsx": {
-      "version": "5.0.1",
-      "resolved": "https://registry.npmjs.org/acorn-jsx/-/acorn-jsx-5.0.1.tgz",
-      "integrity": "sha512-HJ7CfNHrfJLlNTzIEUTj43LNWGkqpRLxm3YjAlcD0ACydk9XynzYsCBHxut+iqt+1aBXkx9UP/w/ZqMr13XIzg==",
+      "version": "5.0.2",
+      "resolved": "https://registry.npmjs.org/acorn-jsx/-/acorn-jsx-5.0.2.tgz",
+      "integrity": "sha512-tiNTrP1MP0QrChmD2DdupCr6HWSFeKVw5d/dHTu4Y7rkAkRhU/Dt7dphAfIUyxtHpl/eBVip5uTNSpQJHylpAw==",
       "dev": true
     },
     "ajv": {
@@ -55,15 +55,18 @@
       "dev": true
     },
     "ansi-escapes": {
-      "version": "3.2.0",
-      "resolved": "https://registry.npmjs.org/ansi-escapes/-/ansi-escapes-3.2.0.tgz",
-      "integrity": "sha512-cBhpre4ma+U0T1oM5fXg7Dy1Jw7zzwv7lt/GoCpr+hDQJoYnKVPLL4dCvSEFMmQurOQvSrwT7SL/DAlhBI97RQ==",
-      "dev": true
+      "version": "4.2.1",
+      "resolved": "https://registry.npmjs.org/ansi-escapes/-/ansi-escapes-4.2.1.tgz",
+      "integrity": "sha512-Cg3ymMAdN10wOk/VYfLV7KCQyv7EDirJ64500sU7n9UlmioEtDuU5Gd+hj73hXSU/ex7tHJSssmyftDdkMLO8Q==",
+      "dev": true,
+      "requires": {
+        "type-fest": "^0.5.2"
+      }
     },
     "ansi-regex": {
-      "version": "3.0.0",
-      "resolved": "https://registry.npmjs.org/ansi-regex/-/ansi-regex-3.0.0.tgz",
-      "integrity": "sha1-7QMXwyIGT3lGbAKWa922Bas32Zg=",
+      "version": "4.1.0",
+      "resolved": "https://registry.npmjs.org/ansi-regex/-/ansi-regex-4.1.0.tgz",
+      "integrity": "sha512-1apePfXM1UOSqw0o9IiFAovVz9M5S1Dg+4TrDwfMewQ6p/rmMueb7tWZjQ1rx4Loy1ArBggoqGpfqqdI4rondg==",
       "dev": true
     },
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@@ -1402,9 +1475,9 @@
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@@ -1428,10 +1501,16 @@
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@@ -1444,15 +1523,6 @@
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@@ -1492,6 +1562,12 @@
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@@ -1506,6 +1582,12 @@
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@@ -1528,6 +1610,39 @@
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+          "integrity": "sha1-7QMXwyIGT3lGbAKWa922Bas32Zg=",
+          "dev": true
+        },
+        "is-fullwidth-code-point": {
+          "version": "2.0.0",
+          "resolved": "https://registry.npmjs.org/is-fullwidth-code-point/-/is-fullwidth-code-point-2.0.0.tgz",
+          "integrity": "sha1-o7MKXE8ZkYMWeqq5O+764937ZU8=",
+          "dev": true
+        },
+        "string-width": {
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+          "resolved": "https://registry.npmjs.org/string-width/-/string-width-2.1.1.tgz",
+          "integrity": "sha512-nOqH59deCq9SRHlxq1Aw85Jnt4w6KvLKqWVik6oA9ZklXLNIOlqg4F2yrT1MVaTjAqvVwdfeZ7w7aCvJD7ugkw==",
+          "dev": true,
+          "requires": {
+            "is-fullwidth-code-point": "^2.0.0",
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+        "strip-ansi": {
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+          "resolved": "https://registry.npmjs.org/strip-ansi/-/strip-ansi-4.0.0.tgz",
+          "integrity": "sha1-qEeQIusaw2iocTibY1JixQXuNo8=",
+          "dev": true,
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@@ -1623,10 +1738,16 @@
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+        "emoji-regex": {
+          "version": "7.0.3",
+          "resolved": "https://registry.npmjs.org/emoji-regex/-/emoji-regex-7.0.3.tgz",
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+          "dev": true
+        },
+        "is-fullwidth-code-point": {
+          "version": "2.0.0",
+          "resolved": "https://registry.npmjs.org/is-fullwidth-code-point/-/is-fullwidth-code-point-2.0.0.tgz",
+          "integrity": "sha1-o7MKXE8ZkYMWeqq5O+764937ZU8=",
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@@ -1639,15 +1760,6 @@
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-          }
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@@ -1672,18 +1784,49 @@
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+          "resolved": "https://registry.npmjs.org/ansi-regex/-/ansi-regex-3.0.0.tgz",
+          "integrity": "sha1-7QMXwyIGT3lGbAKWa922Bas32Zg=",
+          "dev": true
+        },
         "get-caller-file": {
           "version": "1.0.3",
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+        "is-fullwidth-code-point": {
+          "version": "2.0.0",
+          "resolved": "https://registry.npmjs.org/is-fullwidth-code-point/-/is-fullwidth-code-point-2.0.0.tgz",
+          "integrity": "sha1-o7MKXE8ZkYMWeqq5O+764937ZU8=",
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           "dev": true
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+        "string-width": {
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+          "resolved": "https://registry.npmjs.org/string-width/-/string-width-2.1.1.tgz",
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+          "dev": true,
+          "requires": {
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+            "strip-ansi": "^4.0.0"
+          }
+        },
+        "strip-ansi": {
+          "version": "4.0.0",
+          "resolved": "https://registry.npmjs.org/strip-ansi/-/strip-ansi-4.0.0.tgz",
+          "integrity": "sha1-qEeQIusaw2iocTibY1JixQXuNo8=",
+          "dev": true,
+          "requires": {
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diff --git a/tools/lint/eslint/eslint-plugin-mozilla/package.json b/tools/lint/eslint/eslint-plugin-mozilla/package.json
index 5389990b20..49fa2b6d2c 100644
--- a/tools/lint/eslint/eslint-plugin-mozilla/package.json
+++ b/tools/lint/eslint/eslint-plugin-mozilla/package.json
@@ -1,6 +1,6 @@
 {
   "name": "eslint-plugin-mozilla",
-  "version": "2.0.0",
+  "version": "2.1.0",
   "description": "A collection of rules that help enforce JavaScript coding standard in the Mozilla project.",
   "keywords": [
     "eslint",
@@ -25,15 +25,15 @@
     "htmlparser2": "3.10.1"
   },
   "devDependencies": {
-    "eslint": "5.16.0",
-    "mocha": "6.1.4"
+    "eslint": "6.1.0",
+    "mocha": "6.2.0"
   },
   "peerDependencies": {
-    "eslint-config-prettier": "^4.2.0",
+    "eslint-config-prettier": "^6.0.0",
     "eslint-plugin-fetch-options": "^0.0.5",
     "eslint-plugin-no-unsanitized": "^3.0.0",
     "eslint-plugin-prettier": "^3.0.1",
-    "eslint": "^5.0.1",
+    "eslint": "^6.1.0",
     "prettier": "^1.17.0"
   },
   "engines": {
diff --git a/tools/lint/eslint/eslint-plugin-mozilla/tests/avoid-Date-timing.js b/tools/lint/eslint/eslint-plugin-mozilla/tests/avoid-Date-timing.js
index 3f891a5784..597961e8cc 100644
--- a/tools/lint/eslint/eslint-plugin-mozilla/tests/avoid-Date-timing.js
+++ b/tools/lint/eslint/eslint-plugin-mozilla/tests/avoid-Date-timing.js
@@ -8,7 +8,7 @@
 // ------------------------------------------------------------------------------
 
 var rule = require("../lib/rules/avoid-Date-timing");
-var RuleTester = require("eslint/lib/testers/rule-tester");
+var RuleTester = require("eslint").RuleTester;
 
 const ruleTester = new RuleTester({ parserOptions: { ecmaVersion: 6 } });
 
diff --git a/tools/lint/eslint/eslint-plugin-mozilla/tests/avoid-removeChild.js b/tools/lint/eslint/eslint-plugin-mozilla/tests/avoid-removeChild.js
index 76fd872d5d..e6a146898d 100644
--- a/tools/lint/eslint/eslint-plugin-mozilla/tests/avoid-removeChild.js
+++ b/tools/lint/eslint/eslint-plugin-mozilla/tests/avoid-removeChild.js
@@ -8,7 +8,7 @@
 // ------------------------------------------------------------------------------
 
 var rule = require("../lib/rules/avoid-removeChild");
-var RuleTester = require("eslint/lib/testers/rule-tester");
+var RuleTester = require("eslint").RuleTester;
 
 const ruleTester = new RuleTester({ parserOptions: { ecmaVersion: 6 } });
 
diff --git a/tools/lint/eslint/eslint-plugin-mozilla/tests/balanced-listeners.js b/tools/lint/eslint/eslint-plugin-mozilla/tests/balanced-listeners.js
index e360c23704..ca84e3474f 100644
--- a/tools/lint/eslint/eslint-plugin-mozilla/tests/balanced-listeners.js
+++ b/tools/lint/eslint/eslint-plugin-mozilla/tests/balanced-listeners.js
@@ -8,7 +8,7 @@
 // ------------------------------------------------------------------------------
 
 var rule = require("../lib/rules/balanced-listeners");
-var RuleTester = require("eslint/lib/testers/rule-tester");
+var RuleTester = require("eslint").RuleTester;
 
 const ruleTester = new RuleTester({ parserOptions: { ecmaVersion: 6 } });
 
diff --git a/tools/lint/eslint/eslint-plugin-mozilla/tests/consistent-if-bracing.js b/tools/lint/eslint/eslint-plugin-mozilla/tests/consistent-if-bracing.js
index 74aa3a10db..b6b5b849b9 100644
--- a/tools/lint/eslint/eslint-plugin-mozilla/tests/consistent-if-bracing.js
+++ b/tools/lint/eslint/eslint-plugin-mozilla/tests/consistent-if-bracing.js
@@ -8,7 +8,7 @@
 // ------------------------------------------------------------------------------
 
 var rule = require("../lib/rules/consistent-if-bracing");
-var RuleTester = require("eslint/lib/testers/rule-tester");
+var RuleTester = require("eslint").RuleTester;
 
 const ruleTester = new RuleTester({ parserOptions: { ecmaVersion: 8 } });
 
diff --git a/tools/lint/eslint/eslint-plugin-mozilla/tests/mark-exported-symbols-as-used.js b/tools/lint/eslint/eslint-plugin-mozilla/tests/mark-exported-symbols-as-used.js
index 72af8304ff..d004650997 100644
--- a/tools/lint/eslint/eslint-plugin-mozilla/tests/mark-exported-symbols-as-used.js
+++ b/tools/lint/eslint/eslint-plugin-mozilla/tests/mark-exported-symbols-as-used.js
@@ -8,7 +8,7 @@
 // ------------------------------------------------------------------------------
 
 var rule = require("../lib/rules/mark-exported-symbols-as-used");
-var RuleTester = require("eslint/lib/testers/rule-tester");
+var RuleTester = require("eslint").RuleTester;
 
 const ruleTester = new RuleTester({ parserOptions: { ecmaVersion: 6 } });
 
diff --git a/tools/lint/eslint/eslint-plugin-mozilla/tests/no-arbitrary-setTimeout.js b/tools/lint/eslint/eslint-plugin-mozilla/tests/no-arbitrary-setTimeout.js
index 9abb2f9a6b..907b439b3c 100644
--- a/tools/lint/eslint/eslint-plugin-mozilla/tests/no-arbitrary-setTimeout.js
+++ b/tools/lint/eslint/eslint-plugin-mozilla/tests/no-arbitrary-setTimeout.js
@@ -8,7 +8,7 @@
 // ------------------------------------------------------------------------------
 
 var rule = require("../lib/rules/no-arbitrary-setTimeout");
-var RuleTester = require("eslint/lib/testers/rule-tester");
+var RuleTester = require("eslint").RuleTester;
 
 const ruleTester = new RuleTester({ parserOptions: { ecmaVersion: 6 } });
 
diff --git a/tools/lint/eslint/eslint-plugin-mozilla/tests/no-compare-against-boolean-literals.js b/tools/lint/eslint/eslint-plugin-mozilla/tests/no-compare-against-boolean-literals.js
index e2ba8bc1c9..722e6b5dda 100644
--- a/tools/lint/eslint/eslint-plugin-mozilla/tests/no-compare-against-boolean-literals.js
+++ b/tools/lint/eslint/eslint-plugin-mozilla/tests/no-compare-against-boolean-literals.js
@@ -8,7 +8,7 @@
 // ------------------------------------------------------------------------------
 
 var rule = require("../lib/rules/no-compare-against-boolean-literals");
-var RuleTester = require("eslint/lib/testers/rule-tester");
+var RuleTester = require("eslint").RuleTester;
 
 const ruleTester = new RuleTester({ parserOptions: { ecmaVersion: 6 } });
 
diff --git a/tools/lint/eslint/eslint-plugin-mozilla/tests/no-define-cc-etc.js b/tools/lint/eslint/eslint-plugin-mozilla/tests/no-define-cc-etc.js
index 70d6f51ad5..49c2ba0d2e 100644
--- a/tools/lint/eslint/eslint-plugin-mozilla/tests/no-define-cc-etc.js
+++ b/tools/lint/eslint/eslint-plugin-mozilla/tests/no-define-cc-etc.js
@@ -8,7 +8,7 @@
 // ------------------------------------------------------------------------------
 
 var rule = require("../lib/rules/no-define-cc-etc");
-var RuleTester = require("eslint/lib/testers/rule-tester");
+var RuleTester = require("eslint").RuleTester;
 
 const ruleTester = new RuleTester({ parserOptions: { ecmaVersion: 9 } });
 
diff --git a/tools/lint/eslint/eslint-plugin-mozilla/tests/no-useless-parameters.js b/tools/lint/eslint/eslint-plugin-mozilla/tests/no-useless-parameters.js
index 7e7d467540..0c9b12f6eb 100644
--- a/tools/lint/eslint/eslint-plugin-mozilla/tests/no-useless-parameters.js
+++ b/tools/lint/eslint/eslint-plugin-mozilla/tests/no-useless-parameters.js
@@ -8,7 +8,7 @@
 // ------------------------------------------------------------------------------
 
 var rule = require("../lib/rules/no-useless-parameters");
-var RuleTester = require("eslint/lib/testers/rule-tester");
+var RuleTester = require("eslint").RuleTester;
 
 const ruleTester = new RuleTester({ parserOptions: { ecmaVersion: 6 } });
 
diff --git a/tools/lint/eslint/eslint-plugin-mozilla/tests/no-useless-removeEventListener.js b/tools/lint/eslint/eslint-plugin-mozilla/tests/no-useless-removeEventListener.js
index dc857d78c4..9f59c78d05 100644
--- a/tools/lint/eslint/eslint-plugin-mozilla/tests/no-useless-removeEventListener.js
+++ b/tools/lint/eslint/eslint-plugin-mozilla/tests/no-useless-removeEventListener.js
@@ -8,7 +8,7 @@
 // ------------------------------------------------------------------------------
 
 var rule = require("../lib/rules/no-useless-removeEventListener");
-var RuleTester = require("eslint/lib/testers/rule-tester");
+var RuleTester = require("eslint").RuleTester;
 
 const ruleTester = new RuleTester({ parserOptions: { ecmaVersion: 6 } });
 
diff --git a/tools/lint/eslint/eslint-plugin-mozilla/tests/no-useless-run-test.js b/tools/lint/eslint/eslint-plugin-mozilla/tests/no-useless-run-test.js
index 608f84f54d..3541467143 100644
--- a/tools/lint/eslint/eslint-plugin-mozilla/tests/no-useless-run-test.js
+++ b/tools/lint/eslint/eslint-plugin-mozilla/tests/no-useless-run-test.js
@@ -8,7 +8,7 @@
 // ------------------------------------------------------------------------------
 
 var rule = require("../lib/rules/no-useless-run-test");
-var RuleTester = require("eslint/lib/testers/rule-tester");
+var RuleTester = require("eslint").RuleTester;
 
 const ruleTester = new RuleTester({ parserOptions: { ecmaVersion: 6 } });
 
diff --git a/tools/lint/eslint/eslint-plugin-mozilla/tests/reject-importGlobalProperties.js b/tools/lint/eslint/eslint-plugin-mozilla/tests/reject-importGlobalProperties.js
index 6b964dc81a..04c0e0408b 100644
--- a/tools/lint/eslint/eslint-plugin-mozilla/tests/reject-importGlobalProperties.js
+++ b/tools/lint/eslint/eslint-plugin-mozilla/tests/reject-importGlobalProperties.js
@@ -8,7 +8,7 @@
 // ------------------------------------------------------------------------------
 
 var rule = require("../lib/rules/reject-importGlobalProperties");
-var RuleTester = require("eslint/lib/testers/rule-tester");
+var RuleTester = require("eslint").RuleTester;
 
 const ruleTester = new RuleTester({ parserOptions: { ecmaVersion: 8 } });
 
diff --git a/tools/lint/eslint/eslint-plugin-mozilla/tests/rejects-requires-await.js b/tools/lint/eslint/eslint-plugin-mozilla/tests/rejects-requires-await.js
index debf14a493..ea6273a8ee 100644
--- a/tools/lint/eslint/eslint-plugin-mozilla/tests/rejects-requires-await.js
+++ b/tools/lint/eslint/eslint-plugin-mozilla/tests/rejects-requires-await.js
@@ -8,7 +8,7 @@
 // ------------------------------------------------------------------------------
 
 var rule = require("../lib/rules/rejects-requires-await");
-var RuleTester = require("eslint/lib/testers/rule-tester");
+var RuleTester = require("eslint").RuleTester;
 
 const ruleTester = new RuleTester({ parserOptions: { ecmaVersion: 8 } });
 
diff --git a/tools/lint/eslint/eslint-plugin-mozilla/tests/use-cc-etc.js b/tools/lint/eslint/eslint-plugin-mozilla/tests/use-cc-etc.js
index a32d7cc5ad..7ad729d22b 100644
--- a/tools/lint/eslint/eslint-plugin-mozilla/tests/use-cc-etc.js
+++ b/tools/lint/eslint/eslint-plugin-mozilla/tests/use-cc-etc.js
@@ -8,7 +8,7 @@
 // ------------------------------------------------------------------------------
 
 var rule = require("../lib/rules/use-cc-etc");
-var RuleTester = require("eslint/lib/testers/rule-tester");
+var RuleTester = require("eslint").RuleTester;
 
 const ruleTester = new RuleTester({ parserOptions: { ecmaVersion: 6 } });
 
diff --git a/tools/lint/eslint/eslint-plugin-mozilla/tests/use-chromeutils-generateqi.js b/tools/lint/eslint/eslint-plugin-mozilla/tests/use-chromeutils-generateqi.js
index e0f509322e..e696917346 100644
--- a/tools/lint/eslint/eslint-plugin-mozilla/tests/use-chromeutils-generateqi.js
+++ b/tools/lint/eslint/eslint-plugin-mozilla/tests/use-chromeutils-generateqi.js
@@ -8,7 +8,7 @@
 // ------------------------------------------------------------------------------
 
 var rule = require("../lib/rules/use-chromeutils-generateqi");
-var RuleTester = require("eslint/lib/testers/rule-tester");
+var RuleTester = require("eslint").RuleTester;
 
 const ruleTester = new RuleTester({ parserOptions: { ecmaVersion: 6 } });
 
diff --git a/tools/lint/eslint/eslint-plugin-mozilla/tests/use-chromeutils-import.js b/tools/lint/eslint/eslint-plugin-mozilla/tests/use-chromeutils-import.js
index 2f4ee90251..635c436233 100644
--- a/tools/lint/eslint/eslint-plugin-mozilla/tests/use-chromeutils-import.js
+++ b/tools/lint/eslint/eslint-plugin-mozilla/tests/use-chromeutils-import.js
@@ -8,7 +8,7 @@
 // ------------------------------------------------------------------------------
 
 var rule = require("../lib/rules/use-chromeutils-import");
-var RuleTester = require("eslint/lib/testers/rule-tester");
+var RuleTester = require("eslint").RuleTester;
 
 const ruleTester = new RuleTester({ parserOptions: { ecmaVersion: 6 } });
 
diff --git a/tools/lint/eslint/eslint-plugin-mozilla/tests/use-default-preference-values.js b/tools/lint/eslint/eslint-plugin-mozilla/tests/use-default-preference-values.js
index 1473d85c42..f4ad001a08 100644
--- a/tools/lint/eslint/eslint-plugin-mozilla/tests/use-default-preference-values.js
+++ b/tools/lint/eslint/eslint-plugin-mozilla/tests/use-default-preference-values.js
@@ -8,7 +8,7 @@
 // ------------------------------------------------------------------------------
 
 var rule = require("../lib/rules/use-default-preference-values");
-var RuleTester = require("eslint/lib/testers/rule-tester");
+var RuleTester = require("eslint").RuleTester;
 
 const ruleTester = new RuleTester({ parserOptions: { ecmaVersion: 6 } });
 
diff --git a/tools/lint/eslint/eslint-plugin-mozilla/tests/use-includes-instead-of-indexOf.js b/tools/lint/eslint/eslint-plugin-mozilla/tests/use-includes-instead-of-indexOf.js
index 71dc44a76d..cb1810b305 100644
--- a/tools/lint/eslint/eslint-plugin-mozilla/tests/use-includes-instead-of-indexOf.js
+++ b/tools/lint/eslint/eslint-plugin-mozilla/tests/use-includes-instead-of-indexOf.js
@@ -8,7 +8,7 @@
 // ------------------------------------------------------------------------------
 
 var rule = require("../lib/rules/use-includes-instead-of-indexOf");
-var RuleTester = require("eslint/lib/testers/rule-tester");
+var RuleTester = require("eslint").RuleTester;
 
 const ruleTester = new RuleTester({ parserOptions: { ecmaVersion: 6 } });
 
diff --git a/tools/lint/eslint/eslint-plugin-mozilla/tests/use-ownerGlobal.js b/tools/lint/eslint/eslint-plugin-mozilla/tests/use-ownerGlobal.js
index 7be0f53dac..b08bdf1632 100644
--- a/tools/lint/eslint/eslint-plugin-mozilla/tests/use-ownerGlobal.js
+++ b/tools/lint/eslint/eslint-plugin-mozilla/tests/use-ownerGlobal.js
@@ -8,7 +8,7 @@
 // ------------------------------------------------------------------------------
 
 var rule = require("../lib/rules/use-ownerGlobal");
-var RuleTester = require("eslint/lib/testers/rule-tester");
+var RuleTester = require("eslint").RuleTester;
 
 const ruleTester = new RuleTester({ parserOptions: { ecmaVersion: 6 } });
 
diff --git a/tools/lint/eslint/eslint-plugin-mozilla/tests/use-returnValue.js b/tools/lint/eslint/eslint-plugin-mozilla/tests/use-returnValue.js
index 20d7aaa786..81952452e4 100644
--- a/tools/lint/eslint/eslint-plugin-mozilla/tests/use-returnValue.js
+++ b/tools/lint/eslint/eslint-plugin-mozilla/tests/use-returnValue.js
@@ -8,7 +8,7 @@
 // ------------------------------------------------------------------------------
 
 var rule = require("../lib/rules/use-returnValue");
-var RuleTester = require("eslint/lib/testers/rule-tester");
+var RuleTester = require("eslint").RuleTester;
 
 const ruleTester = new RuleTester({ parserOptions: { ecmaVersion: 6 } });
 
diff --git a/tools/lint/eslint/eslint-plugin-mozilla/tests/use-services.js b/tools/lint/eslint/eslint-plugin-mozilla/tests/use-services.js
deleted file mode 100644
index d26b68294c..0000000000
--- a/tools/lint/eslint/eslint-plugin-mozilla/tests/use-services.js
+++ /dev/null
@@ -1,40 +0,0 @@
-/* Any copyright is dedicated to the Public Domain.
- * http://creativecommons.org/publicdomain/zero/1.0/ */
-
-"use strict";
-
-// ------------------------------------------------------------------------------
-// Requirements
-// ------------------------------------------------------------------------------
-
-var rule = require("../lib/rules/use-services");
-var RuleTester = require("eslint/lib/testers/rule-tester");
-
-const ruleTester = new RuleTester({ parserOptions: { ecmaVersion: 6 } });
-
-// ------------------------------------------------------------------------------
-// Tests
-// ------------------------------------------------------------------------------
-
-function invalidCode(code, name) {
-  let message = `Use Services.${name} rather than getService().`;
-  return { code, errors: [{ message, type: "CallExpression" }] };
-}
-
-ruleTester.run("use-services", rule, {
-  valid: [
-    'Cc["@mozilla.org/uuid-generator;1"].getService(Ci.nsIUUIDGenerator)',
-    'Components.classes["@mozilla.org/uuid-generator;1"].getService(Components.interfaces.nsIUUIDGenerator)',
-    "Services.wm.addListener()",
-  ],
-  invalid: [
-    invalidCode(
-      'Cc["@mozilla.org/appshell/window-mediator;1"].getService(Ci.nsIWindowMediator);',
-      "wm"
-    ),
-    invalidCode(
-      'Components.classes["@mozilla.org/toolkit/app-startup;1"].getService(Components.interfaces.nsIAppStartup);',
-      "startup"
-    ),
-  ],
-});
diff --git a/tools/lint/eslint/eslint-plugin-spidermonkey-js/lib/index.js b/tools/lint/eslint/eslint-plugin-spidermonkey-js/lib/index.js
index a54505aea2..4fb6e340ed 100644
--- a/tools/lint/eslint/eslint-plugin-spidermonkey-js/lib/index.js
+++ b/tools/lint/eslint/eslint-plugin-spidermonkey-js/lib/index.js
@@ -12,6 +12,6 @@
 // ------------------------------------------------------------------------------
 module.exports = {
   processors: {
-    ".js": require("../lib/processors/self-hosted"),
+    processor: require("../lib/processors/self-hosted"),
   },
 };
diff --git a/tools/lint/eslint/manifest.tt b/tools/lint/eslint/manifest.tt
index 11eeedcd58..5253946031 100644
--- a/tools/lint/eslint/manifest.tt
+++ b/tools/lint/eslint/manifest.tt
@@ -4,7 +4,7 @@
     "visibility": "public",
     "filename": "eslint.tar.gz",
     "unpack": true,
-    "digest": "51de863dc5775bedea68538d185dc2fe0149bf263399951d549205fd9e9ebd6a46bc7c95fa02adcf21ecc22654eb368fd5c31f146b1521e2155639188159cf93",
-    "size": 7399474
+    "digest": "dcbe1cb0526d8a120fdb5a268212c37d1b26f4e07dee2e33f17275578eb7f487a4316af76687839205a905b28f6deaadf4d9f788d56f9e102ee4d210930b30a1",
+    "size": 8914031
   }
-]
+]
\ No newline at end of file
diff --git a/tools/lint/eslint/modules.json b/tools/lint/eslint/modules.json
index ffd80fa88f..8c56cd5d39 100644
--- a/tools/lint/eslint/modules.json
+++ b/tools/lint/eslint/modules.json
@@ -186,7 +186,6 @@
   "resource://testing-common/services/sync/utils.js": ["AccountState", "MockFxaStorageManager", "SyncTestingInfrastructure", "configureFxAccountIdentity", "configureIdentity", "encryptPayload", "getLoginTelemetryScalar", "makeFxAccountsInternalMock", "makeIdentityConfig", "promiseNamedTimer", "promiseZeroTimer", "sumHistogram", "syncTestLogging", "waitForZeroTimer"],
   "rest.js": ["RESTRequest", "RESTResponse", "TokenAuthenticatedRESTRequest"],
   "rotaryengine.js": ["RotaryEngine", "RotaryRecord", "RotaryStore", "RotaryTracker"],
-  "RTCStatsReport.jsm": ["convertToRTCStatsReport"],
   "Schemas.jsm": ["SchemaRoot", "Schemas"],
   "scratchpad-manager.jsm": ["ScratchpadManager"],
   "SearchShortcuts.jsm": ["checkHasSearchEngine", "getSearchProvider", "SEARCH_SHORTCUTS", "CUSTOM_SEARCH_SHORTCUTS", "SEARCH_SHORTCUTS_EXPERIMENT", "SEARCH_SHORTCUTS_SEARCH_ENGINES_PREF", "SEARCH_SHORTCUTS_HAVE_PINNED_PREF"],
diff --git a/tools/lint/spell/codespell_requirements.txt b/tools/lint/spell/codespell_requirements.txt
index 22edc8ab78..ceffdf96c7 100644
--- a/tools/lint/spell/codespell_requirements.txt
+++ b/tools/lint/spell/codespell_requirements.txt
@@ -1,2 +1,2 @@
-codespell==1.14.0 \
-    --hash=sha256:b1b60867773ffc5643a3724b62d12fe6797aa735831733f8a45f6d28db5ef34f
+codespell==1.15.0 \
+    --hash=sha256:8f1bc15ca4322b72213b1cf13eb437b3c3956e0f423ab414d294d7e77e0e4130
diff --git a/tools/lint/spell/exclude-list.txt b/tools/lint/spell/exclude-list.txt
index a826f611a4..79674c437b 100644
--- a/tools/lint/spell/exclude-list.txt
+++ b/tools/lint/spell/exclude-list.txt
@@ -7,3 +7,6 @@ wasn
 incrementall
 aare
 whats
+crate
+files'
+thru
diff --git a/tools/profiler/core/ProfileBuffer.cpp b/tools/profiler/core/ProfileBuffer.cpp
index aec8b0eb63..91e69d70bf 100644
--- a/tools/profiler/core/ProfileBuffer.cpp
+++ b/tools/profiler/core/ProfileBuffer.cpp
@@ -4,8 +4,8 @@
 
 #include "ProfileBuffer.h"
 
-#include "ProfilerMarker.h"
-
+#include "BaseProfiler.h"
+#include "js/GCAPI.h"
 #include "jsfriendapi.h"
 #include "mozilla/MathAlgorithms.h"
 #include "nsJSPrincipals.h"
@@ -13,44 +13,63 @@
 
 using namespace mozilla;
 
-ProfileBuffer::ProfileBuffer(uint32_t aCapacity)
-    : mEntryIndexMask(0), mRangeStart(0), mRangeEnd(0), mCapacity(0) {
-  // Round aCapacity up to the nearest power of two, so that we can index
-  // mEntries with a simple mask and don't need to do a slow modulo operation.
-  const uint32_t UINT32_MAX_POWER_OF_TWO = 1 << 31;
-  MOZ_RELEASE_ASSERT(aCapacity <= UINT32_MAX_POWER_OF_TWO,
-                     "aCapacity is larger than what we support");
-  mCapacity = RoundUpPow2(aCapacity);
-  mEntryIndexMask = mCapacity - 1;
-  mEntries = MakeUnique<ProfileBufferEntry[]>(mCapacity);
+// 65536 bytes should be plenty for a single backtrace.
+static constexpr auto WorkerBufferBytes = MakePowerOfTwo32<65536>();
+
+ProfileBuffer::ProfileBuffer(BlocksRingBuffer& aBuffer, PowerOfTwo32 aCapacity)
+    : mEntries(aBuffer),
+      mWorkerBuffer(
+          MakeUnique<BlocksRingBuffer::Byte[]>(WorkerBufferBytes.Value())) {
+  // Only ProfileBuffer should control this buffer, and it should be empty when
+  // there is no ProfileBuffer using it.
+  MOZ_ASSERT(mEntries.BufferLength().isNothing());
+  // Allocate the requested capacity.
+  mEntries.Set(aCapacity);
+}
+
+ProfileBuffer::ProfileBuffer(BlocksRingBuffer& aBuffer) : mEntries(aBuffer) {
+  // Assume the given buffer is not empty.
+  MOZ_ASSERT(mEntries.BufferLength().isSome());
 }
 
 ProfileBuffer::~ProfileBuffer() {
-  while (mStoredMarkers.peek()) {
-    delete mStoredMarkers.popHead();
+  // Only ProfileBuffer controls this buffer, and it should be empty when there
+  // is no ProfileBuffer using it.
+  mEntries.Reset();
+  MOZ_ASSERT(mEntries.BufferLength().isNothing());
+}
+
+/* static */
+BlocksRingBuffer::BlockIndex ProfileBuffer::AddEntry(
+    BlocksRingBuffer& aBlocksRingBuffer, const ProfileBufferEntry& aEntry) {
+  switch (aEntry.GetKind()) {
+#define SWITCH_KIND(KIND, TYPE, SIZE)                      \
+  case ProfileBufferEntry::Kind::KIND: {                   \
+    return aBlocksRingBuffer.PutFrom(&aEntry, 1 + (SIZE)); \
+  }
+
+    FOR_EACH_PROFILE_BUFFER_ENTRY_KIND(SWITCH_KIND)
+
+#undef SWITCH_KIND
+    default:
+      MOZ_ASSERT(false, "Unhandled ProfilerBuffer entry KIND");
+      return BlockIndex{};
   }
 }
 
 // Called from signal, call only reentrant functions
-void ProfileBuffer::AddEntry(const ProfileBufferEntry& aEntry) {
-  GetEntry(mRangeEnd++) = aEntry;
+uint64_t ProfileBuffer::AddEntry(const ProfileBufferEntry& aEntry) {
+  return AddEntry(mEntries, aEntry).ConvertToU64();
+}
 
-  // The distance between mRangeStart and mRangeEnd must never exceed
-  // mCapacity, so advance mRangeStart if necessary.
-  if (mRangeEnd - mRangeStart > mCapacity) {
-    mRangeStart++;
-  }
+/* static */
+BlocksRingBuffer::BlockIndex ProfileBuffer::AddThreadIdEntry(
+    BlocksRingBuffer& aBlocksRingBuffer, int aThreadId) {
+  return AddEntry(aBlocksRingBuffer, ProfileBufferEntry::ThreadId(aThreadId));
 }
 
 uint64_t ProfileBuffer::AddThreadIdEntry(int aThreadId) {
-  uint64_t pos = mRangeEnd;
-  AddEntry(ProfileBufferEntry::ThreadId(aThreadId));
-  return pos;
-}
-
-void ProfileBuffer::AddStoredMarker(ProfilerMarker* aStoredMarker) {
-  aStoredMarker->SetPositionInBuffer(mRangeEnd);
-  mStoredMarkers.insert(aStoredMarker);
+  return AddThreadIdEntry(mEntries, aThreadId).ConvertToU64();
 }
 
 void ProfileBuffer::CollectCodeLocation(
@@ -90,26 +109,61 @@ void ProfileBuffer::CollectCodeLocation(
   }
 }
 
-void ProfileBuffer::DeleteExpiredStoredMarkers() {
-  // Delete markers of samples that have been overwritten due to circular
-  // buffer wraparound.
-  while (mStoredMarkers.peek() &&
-         mStoredMarkers.peek()->HasExpired(mRangeStart)) {
-    delete mStoredMarkers.popHead();
-  }
-}
-
-size_t ProfileBuffer::SizeOfIncludingThis(
-    mozilla::MallocSizeOf aMallocSizeOf) const {
-  size_t n = aMallocSizeOf(this);
-  n += aMallocSizeOf(mEntries.get());
-
+size_t ProfileBuffer::SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const {
   // Measurement of the following members may be added later if DMD finds it
   // is worthwhile:
   // - memory pointed to by the elements within mEntries
-  // - mStoredMarkers
+  return mEntries.SizeOfExcludingThis(aMallocSizeOf);
+}
 
-  return n;
+size_t ProfileBuffer::SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const {
+  return aMallocSizeOf(this) + SizeOfExcludingThis(aMallocSizeOf);
+}
+
+void ProfileBuffer::CollectOverheadStats(TimeDuration aSamplingTime,
+                                         TimeDuration aLocking,
+                                         TimeDuration aCleaning,
+                                         TimeDuration aCounters,
+                                         TimeDuration aThreads) {
+  double time = aSamplingTime.ToMilliseconds() * 1000.0;
+  if (mFirstSamplingTimeNs == 0.0) {
+    mFirstSamplingTimeNs = time;
+  } else {
+    // Note that we'll have 1 fewer interval than other numbers (because
+    // we need both ends of an interval to know its duration). The final
+    // difference should be insignificant over the expected many thousands
+    // of iterations.
+    mIntervalsNs.Count(time - mLastSamplingTimeNs);
+  }
+  mLastSamplingTimeNs = time;
+  double locking = aLocking.ToMilliseconds() * 1000.0;
+  double cleaning = aCleaning.ToMilliseconds() * 1000.0;
+  double counters = aCounters.ToMilliseconds() * 1000.0;
+  double threads = aThreads.ToMilliseconds() * 1000.0;
+
+  mOverheadsNs.Count(locking + cleaning + counters + threads);
+  mLockingsNs.Count(locking);
+  mCleaningsNs.Count(cleaning);
+  mCountersNs.Count(counters);
+  mThreadsNs.Count(threads);
+
+  AddEntry(ProfileBufferEntry::ProfilerOverheadTime(time));
+  AddEntry(ProfileBufferEntry::ProfilerOverheadDuration(locking));
+  AddEntry(ProfileBufferEntry::ProfilerOverheadDuration(cleaning));
+  AddEntry(ProfileBufferEntry::ProfilerOverheadDuration(counters));
+  AddEntry(ProfileBufferEntry::ProfilerOverheadDuration(threads));
+}
+
+ProfilerBufferInfo ProfileBuffer::GetProfilerBufferInfo() const {
+  return {BufferRangeStart(),
+          BufferRangeEnd(),
+          mEntries.BufferLength()->Value() / 8,  // 8 bytes per entry.
+          mIntervalsNs,
+          mOverheadsNs,
+          mLockingsNs,
+          mCleaningsNs,
+          mCountersNs,
+          mThreadsNs};
 }
 
 /* ProfileBufferCollector */
diff --git a/tools/profiler/core/ProfileBuffer.h b/tools/profiler/core/ProfileBuffer.h
index e945b65f75..070f3a345a 100644
--- a/tools/profiler/core/ProfileBuffer.h
+++ b/tools/profiler/core/ProfileBuffer.h
@@ -5,35 +5,42 @@
 #ifndef MOZ_PROFILE_BUFFER_H
 #define MOZ_PROFILE_BUFFER_H
 
+#include "GeckoProfiler.h"
 #include "ProfileBufferEntry.h"
-#include "ProfilerMarker.h"
 
+#include "mozilla/BlocksRingBuffer.h"
 #include "mozilla/Maybe.h"
+#include "mozilla/PowerOfTwo.h"
 
-// A fixed-capacity circular buffer.
+// Class storing most profiling data in a BlocksRingBuffer.
+//
 // This class is used as a queue of entries which, after construction, never
 // allocates. This makes it safe to use in the profiler's "critical section".
-// Entries are appended at the end. Once the queue capacity has been reached,
-// adding a new entry will evict an old entry from the start of the queue.
-// Positions in the queue are represented as 64-bit unsigned integers which
-// only increase and never wrap around.
-// mRangeStart and mRangeEnd describe the range in that uint64_t space which is
-// covered by the queue contents.
-// Internally, the buffer uses a fixed-size storage and applies a modulo
-// operation when accessing entries in that storage buffer. "Evicting" an entry
-// really just means that an existing entry in the storage buffer gets
-// overwritten and that mRangeStart gets incremented.
 class ProfileBuffer final {
  public:
+  // Opaque type containing a block index, which should not be modified outside
+  // of BlocksRingBuffer.
+  // TODO: Eventually, all uint64_t values should be replaced with BlockIndex,
+  // because external users should only store and compare them, but not do other
+  // arithmetic operations (that uint64_t supports).
+  using BlockIndex = mozilla::BlocksRingBuffer::BlockIndex;
+
   // ProfileBuffer constructor
-  // @param aCapacity The minimum capacity of the buffer. The actual buffer
-  //                   capacity will be rounded up to the next power of two.
-  explicit ProfileBuffer(uint32_t aCapacity);
+  // @param aBuffer The empty BlocksRingBuffer to use as buffer manager.
+  // @param aCapacity The capacity of the buffer.
+  ProfileBuffer(mozilla::BlocksRingBuffer& aBuffer,
+                mozilla::PowerOfTwo32 aCapacity);
+
+  // ProfileBuffer constructor
+  // @param aBuffer The pre-filled BlocksRingBuffer to use as buffer manager.
+  explicit ProfileBuffer(mozilla::BlocksRingBuffer& aBuffer);
 
   ~ProfileBuffer();
 
+  bool IsThreadSafe() const { return mEntries.IsThreadSafe(); }
+
   // Add |aEntry| to the buffer, ignoring what kind of entry it is.
-  void AddEntry(const ProfileBufferEntry& aEntry);
+  uint64_t AddEntry(const ProfileBufferEntry& aEntry);
 
   // Add to the buffer a sample start (ThreadId) entry for aThreadId.
   // Returns the position of the entry.
@@ -79,9 +86,6 @@ class ProfileBuffer final {
   void StreamCountersToJSON(SpliceableJSONWriter& aWriter,
                             const mozilla::TimeStamp& aProcessStartTime,
                             double aSinceTime) const;
-  void StreamMemoryToJSON(SpliceableJSONWriter& aWriter,
-                          const mozilla::TimeStamp& aProcessStartTime,
-                          double aSinceTime) const;
 
   // Find (via |aLastSample|) the most recent sample for the thread denoted by
   // |aThreadId| and clone it, patching in the current time as appropriate.
@@ -93,52 +97,91 @@ class ProfileBuffer final {
 
   void DiscardSamplesBeforeTime(double aTime);
 
-  void AddStoredMarker(ProfilerMarker* aStoredMarker);
-
-  // The following method is not signal safe!
-  void DeleteExpiredStoredMarkers();
-
-  // Access an entry in the buffer.
-  ProfileBufferEntry& GetEntry(uint64_t aPosition) const {
-    return mEntries[aPosition & mEntryIndexMask];
+  // Read an entry in the buffer. Slow!
+  ProfileBufferEntry GetEntry(uint64_t aPosition) const {
+    ProfileBufferEntry entry;
+    mEntries.Read([&](mozilla::BlocksRingBuffer::Reader* aReader) {
+      // BlocksRingBuffer cannot be out-of-session when sampler is running.
+      MOZ_ASSERT(aReader);
+      for (mozilla::BlocksRingBuffer::EntryReader er : *aReader) {
+        if (er.CurrentBlockIndex().ConvertToU64() > aPosition) {
+          // Passed the block. (We need a precise position.)
+          return;
+        }
+        if (er.CurrentBlockIndex().ConvertToU64() == aPosition) {
+          MOZ_RELEASE_ASSERT(er.RemainingBytes() <= sizeof(entry));
+          er.Read(&entry, er.RemainingBytes());
+          return;
+        }
+      }
+    });
+    return entry;
   }
 
+  size_t SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const;
   size_t SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const;
 
- private:
-  // The storage that backs our buffer. Holds mCapacity entries.
-  // All accesses to entries in mEntries need to go through GetEntry(), which
-  // translates the given buffer position from the near-infinite uint64_t space
-  // into the entry storage space.
-  mozilla::UniquePtr<ProfileBufferEntry[]> mEntries;
+  void CollectOverheadStats(mozilla::TimeDuration aSamplingTime,
+                            mozilla::TimeDuration aLocking,
+                            mozilla::TimeDuration aCleaning,
+                            mozilla::TimeDuration aCounters,
+                            mozilla::TimeDuration aThreads);
 
-  // A mask such that pos & mEntryIndexMask == pos % mCapacity.
-  uint32_t mEntryIndexMask;
+  ProfilerBufferInfo GetProfilerBufferInfo() const;
+
+ private:
+  // Add |aEntry| to the provided BlocksRingBuffer.
+  // `static` because it may be used to add an entry to a `BlocksRingBuffer`
+  // that is not attached to a `ProfileBuffer`.
+  static BlockIndex AddEntry(mozilla::BlocksRingBuffer& aBlocksRingBuffer,
+                             const ProfileBufferEntry& aEntry);
+
+  // Add a sample start (ThreadId) entry for aThreadId to the provided
+  // BlocksRingBuffer. Returns the position of the entry.
+  // `static` because it may be used to add an entry to a `BlocksRingBuffer`
+  // that is not attached to a `ProfileBuffer`.
+  static BlockIndex AddThreadIdEntry(
+      mozilla::BlocksRingBuffer& aBlocksRingBuffer, int aThreadId);
+
+  // The circular-ring storage in which this ProfileBuffer stores its data.
+  mozilla::BlocksRingBuffer& mEntries;
 
  public:
-  // mRangeStart and mRangeEnd are uint64_t values that strictly advance and
-  // never wrap around. mRangeEnd is always greater than or equal to
-  // mRangeStart, but never gets more than mCapacity steps ahead of
-  // mRangeStart, because we can only store a fixed number of entries in the
-  // buffer. Once the entire buffer is in use, adding a new entry will evict an
-  // entry from the front of the buffer (and increase mRangeStart).
-  // In other words, the following conditions hold true at all times:
-  //  (1) mRangeStart <= mRangeEnd
-  //  (2) mRangeEnd - mRangeStart <= mCapacity
+  // `BufferRangeStart()` and `BufferRangeEnd()` return `uint64_t` values
+  // corresponding to the first entry and past the last entry stored in
+  // `mEntries`.
   //
-  // If there are no live entries, then mRangeStart == mRangeEnd.
-  // Otherwise, mRangeStart is the first live entry and mRangeEnd is one past
-  // the last live entry, and also the position at which the next entry will be
-  // added.
-  // (mRangeEnd - mRangeStart) always gives the number of live entries.
-  uint64_t mRangeStart;
-  uint64_t mRangeEnd;
+  // The returned values are not guaranteed to be stable, because other threads
+  // may also be accessing the buffer concurrently. But they will always
+  // increase, and can therefore give an indication of how far these values have
+  // *at least* reached. In particular:
+  // - Entries whose index is strictly less that `BufferRangeStart()` have been
+  //   discarded by now, so any related data may also be safely discarded.
+  // - It is safe to try and read entries at any index strictly less than
+  //   `BufferRangeEnd()` -- but note that these reads may fail by the time you
+  //   request them, as old entries get overwritten by new ones.
+  uint64_t BufferRangeStart() const {
+    return mEntries.GetState().mRangeStart.ConvertToU64();
+  }
+  uint64_t BufferRangeEnd() const {
+    return mEntries.GetState().mRangeEnd.ConvertToU64();
+  }
 
-  // The number of entries in our buffer. Always a power of two.
-  uint32_t mCapacity;
+ private:
+  // Pre-allocated (to avoid spurious mallocs) temporary buffer used when:
+  // - Duplicating sleeping stacks.
+  // - Adding JIT info.
+  // - Streaming stacks to JSON.
+  mozilla::UniquePtr<mozilla::BlocksRingBuffer::Byte[]> mWorkerBuffer;
 
-  // Markers that marker entries in the buffer might refer to.
-  ProfilerMarkerLinkedList mStoredMarkers;
+  double mFirstSamplingTimeNs = 0.0;
+  double mLastSamplingTimeNs = 0.0;
+  ProfilerStats mIntervalsNs;
+  ProfilerStats mOverheadsNs;
+  ProfilerStats mLockingsNs;
+  ProfilerStats mCleaningsNs;
+  ProfilerStats mCountersNs;
+  ProfilerStats mThreadsNs;
 };
 
 /**
@@ -158,7 +201,7 @@ class ProfileBufferCollector final : public ProfilerStackCollector {
   }
 
   mozilla::Maybe<uint64_t> BufferRangeStart() override {
-    return mozilla::Some(mBuf.mRangeStart);
+    return mozilla::Some(mBuf.BufferRangeStart());
   }
 
   virtual void CollectNativeLeafAddr(void* aAddr) override;
diff --git a/tools/profiler/core/ProfileBufferEntry.cpp b/tools/profiler/core/ProfileBufferEntry.cpp
index c77f5be152..d2e600a14c 100644
--- a/tools/profiler/core/ProfileBufferEntry.cpp
+++ b/tools/profiler/core/ProfileBufferEntry.cpp
@@ -6,6 +6,7 @@
 
 #include "platform.h"
 #include "ProfileBuffer.h"
+#include "ProfilerMarkerPayload.h"
 
 #include "jsapi.h"
 #include "jsfriendapi.h"
@@ -14,6 +15,7 @@
 #include "mozilla/StackWalk.h"
 #include "nsThreadUtils.h"
 #include "nsXULAppAPI.h"
+#include "ProfilerCodeAddressService.h"
 
 #include <ostream>
 
@@ -28,11 +30,13 @@ ProfileBufferEntry::ProfileBufferEntry()
 // aString must be a static string.
 ProfileBufferEntry::ProfileBufferEntry(Kind aKind, const char* aString)
     : mKind(aKind) {
+  MOZ_ASSERT(aKind == Kind::Label);
   memcpy(mStorage, &aString, sizeof(aString));
 }
 
 ProfileBufferEntry::ProfileBufferEntry(Kind aKind, char aChars[kNumChars])
     : mKind(aKind) {
+  MOZ_ASSERT(aKind == Kind::DynamicStringFragment);
   memcpy(mStorage, aChars, kNumChars);
 }
 
@@ -40,11 +44,6 @@ ProfileBufferEntry::ProfileBufferEntry(Kind aKind, void* aPtr) : mKind(aKind) {
   memcpy(mStorage, &aPtr, sizeof(aPtr));
 }
 
-ProfileBufferEntry::ProfileBufferEntry(Kind aKind, ProfilerMarker* aMarker)
-    : mKind(aKind) {
-  memcpy(mStorage, &aMarker, sizeof(aMarker));
-}
-
 ProfileBufferEntry::ProfileBufferEntry(Kind aKind, double aDouble)
     : mKind(aKind) {
   memcpy(mStorage, &aDouble, sizeof(aDouble));
@@ -76,12 +75,6 @@ void* ProfileBufferEntry::GetPtr() const {
   return result;
 }
 
-ProfilerMarker* ProfileBufferEntry::GetMarker() const {
-  ProfilerMarker* result;
-  memcpy(&result, mStorage, sizeof(result));
-  return result;
-}
-
 double ProfileBufferEntry::GetDouble() const {
   double result;
   memcpy(&result, mStorage, sizeof(result));
@@ -321,17 +314,6 @@ uint32_t UniqueStacks::GetOrAddStackIndex(const StackKey& aStack) {
   return count;
 }
 
-template <typename RangeT, typename PosT>
-struct PositionInRangeComparator final {
-  bool Equals(const RangeT& aRange, PosT aPos) const {
-    return aRange.mRangeStart <= aPos && aPos < aRange.mRangeEnd;
-  }
-
-  bool LessThan(const RangeT& aRange, PosT aPos) const {
-    return aRange.mRangeEnd <= aPos;
-  }
-};
-
 Maybe<Vector<UniqueStacks::FrameKey>>
 UniqueStacks::LookupFramesForJITAddressFromBufferPos(void* aJITAddress,
                                                      uint64_t aBufferPos) {
@@ -421,7 +403,8 @@ void UniqueStacks::StreamNonJITFrame(const FrameKey& aFrame) {
     OPTIMIZATIONS = 3,
     LINE = 4,
     COLUMN = 5,
-    CATEGORY = 6
+    CATEGORY = 6,
+    SUBCATEGORY = 7
   };
 
   AutoArraySchemaWriter writer(mFrameTableWriter, *mUniqueStrings);
@@ -439,6 +422,7 @@ void UniqueStacks::StreamNonJITFrame(const FrameKey& aFrame) {
     const JS::ProfilingCategoryPairInfo& info =
         JS::GetProfilingCategoryPairInfo(*data.mCategoryPair);
     writer.IntElement(CATEGORY, uint32_t(info.mCategory));
+    writer.IntElement(SUBCATEGORY, info.mSubcategoryIndex);
   }
 }
 
@@ -452,7 +436,8 @@ static void StreamJITFrame(JSContext* aContext, SpliceableJSONWriter& aWriter,
     OPTIMIZATIONS = 3,
     LINE = 4,
     COLUMN = 5,
-    CATEGORY = 6
+    CATEGORY = 6,
+    SUBCATEGORY = 7
   };
 
   AutoArraySchemaWriter writer(aWriter, aUniqueStrings);
@@ -467,6 +452,10 @@ static void StreamJITFrame(JSContext* aContext, SpliceableJSONWriter& aWriter,
       IMPLEMENTATION,
       frameKind == JS::ProfilingFrameIterator::Frame_Ion ? "ion" : "baseline");
 
+  const JS::ProfilingCategoryPairInfo& info =
+      JS::GetProfilingCategoryPairInfo(JS::ProfilingCategoryPair::JS);
+  writer.IntElement(CATEGORY, uint32_t(info.mCategory));
+  writer.IntElement(SUBCATEGORY, info.mSubcategoryIndex);
 }
 
 struct CStringWriteFunc : public JSONWriteFunc {
@@ -537,8 +526,6 @@ struct ProfileSample {
   uint32_t mStack;
   double mTime;
   Maybe<double> mResponsiveness;
-  Maybe<double> mRSS;
-  Maybe<double> mUSS;
 };
 
 static void WriteSample(SpliceableJSONWriter& aWriter,
@@ -548,8 +535,6 @@ static void WriteSample(SpliceableJSONWriter& aWriter,
     STACK = 0,
     TIME = 1,
     RESPONSIVENESS = 2,
-    RSS = 3,
-    USS = 4
   };
 
   AutoArraySchemaWriter writer(aWriter, aUniqueStrings);
@@ -561,36 +546,75 @@ static void WriteSample(SpliceableJSONWriter& aWriter,
   if (aSample.mResponsiveness.isSome()) {
     writer.DoubleElement(RESPONSIVENESS, *aSample.mResponsiveness);
   }
-
-  if (aSample.mRSS.isSome()) {
-    writer.DoubleElement(RSS, *aSample.mRSS);
-  }
-
-  if (aSample.mUSS.isSome()) {
-    writer.DoubleElement(USS, *aSample.mUSS);
-  }
 }
 
 class EntryGetter {
  public:
-  explicit EntryGetter(const ProfileBuffer& aBuffer,
+  explicit EntryGetter(BlocksRingBuffer::Reader& aReader,
                        uint64_t aInitialReadPos = 0)
-      : mBuffer(aBuffer), mReadPos(aBuffer.mRangeStart) {
-    if (aInitialReadPos != 0) {
-      MOZ_RELEASE_ASSERT(aInitialReadPos >= aBuffer.mRangeStart &&
-                         aInitialReadPos <= aBuffer.mRangeEnd);
-      mReadPos = aInitialReadPos;
+      : mBlockIt(aReader.At(
+            BlocksRingBuffer::BlockIndex::ConvertFromU64(aInitialReadPos))),
+        mBlockItEnd(aReader.end()) {
+    if (!ReadLegacyOrEnd()) {
+      // Find and read the next non-legacy entry.
+      Next();
     }
   }
 
-  bool Has() const { return mReadPos != mBuffer.mRangeEnd; }
-  const ProfileBufferEntry& Get() const { return mBuffer.GetEntry(mReadPos); }
-  void Next() { mReadPos++; }
-  uint64_t CurPos() { return mReadPos; }
+  bool Has() const { return mBlockIt != mBlockItEnd; }
+
+  const ProfileBufferEntry& Get() const {
+    MOZ_ASSERT(Has(), "Caller should have checked `Has()` before `Get()`");
+    return mEntry;
+  }
+
+  void Next() {
+    MOZ_ASSERT(Has(), "Caller should have checked `Has()` before `Get()`");
+    for (;;) {
+      ++mBlockIt;
+      if (ReadLegacyOrEnd()) {
+        // Either we're at the end, or we could read a legacy entry -> Done.
+        break;
+      }
+      // Otherwise loop around until we hit a legacy entry or the end.
+    }
+  }
+
+  BlocksRingBuffer::BlockIterator Iterator() const { return mBlockIt; }
+
+  ProfileBuffer::BlockIndex CurBlockIndex() const {
+    return mBlockIt.CurrentBlockIndex();
+  }
+
+  uint64_t CurPos() const { return CurBlockIndex().ConvertToU64(); }
 
  private:
-  const ProfileBuffer& mBuffer;
-  uint64_t mReadPos;
+  // Try to read the entry at the current `mBlockIt` position.
+  // * If we're at the end of the buffer, just return `true`.
+  // * If there is a "legacy" entry (containing a real `ProfileBufferEntry`),
+  //   read it into `mEntry`, and return `true` as well.
+  // * Otherwise the entry contains a "modern" type that cannot be read into
+  // `mEntry`, return `false` (so `EntryGetter` can skip to another entry).
+  bool ReadLegacyOrEnd() {
+    if (!Has()) {
+      return true;
+    }
+    BlocksRingBuffer::EntryReader aER = *mBlockIt;
+    auto type = static_cast<ProfileBufferEntry::Kind>(
+        aER.PeekObject<ProfileBufferEntry::KindUnderlyingType>());
+    MOZ_ASSERT(static_cast<ProfileBufferEntry::KindUnderlyingType>(type) <
+               static_cast<ProfileBufferEntry::KindUnderlyingType>(
+                   ProfileBufferEntry::Kind::MODERN_LIMIT));
+    if (type >= ProfileBufferEntry::Kind::LEGACY_LIMIT) {
+      return false;
+    }
+    aER.Read(&mEntry, aER.RemainingBytes());
+    return true;
+  }
+
+  ProfileBufferEntry mEntry;
+  BlocksRingBuffer::BlockIterator mBlockIt;
+  const BlocksRingBuffer::BlockIterator mBlockItEnd;
 };
 
 // The following grammar shows legal sequences of profile buffer entries.
@@ -599,17 +623,18 @@ class EntryGetter {
 // (
 //   ( /* Samples */
 //     ThreadId
-//     Time
-//     ( NativeLeafAddr
-//     | Label FrameFlags? DynamicStringFragment* LineNumber? CategoryPair?
-//     | JitReturnAddr
-//     )+
-//     Marker*
-//     Responsiveness?
-//     ResidentMemory?
-//     UnsharedMemory?
+//     TimeBeforeCompactStack
+//     UnresponsivenessDurationMs?
+//     CompactStack
+//         /* internally including:
+//           ( NativeLeafAddr
+//           | Label FrameFlags? DynamicStringFragment*
+//             LineNumber? CategoryPair?
+//           | JitReturnAddr
+//           )+
+//         */
 //   )
-//   | ( ResidentMemory UnsharedMemory? Time)  /* Memory */
+//   | MarkerData
 //   | ( /* Counters */
 //       CounterId
 //       Time
@@ -740,239 +765,275 @@ void ProfileBuffer::StreamSamplesToJSON(SpliceableJSONWriter& aWriter,
                                         UniqueStacks& aUniqueStacks) const {
   UniquePtr<char[]> dynStrBuf = MakeUnique<char[]>(kMaxFrameKeyLength);
 
-  EntryGetter e(*this);
+  mEntries.Read([&](BlocksRingBuffer::Reader* aReader) {
+    MOZ_ASSERT(
+        aReader,
+        "BlocksRingBuffer cannot be out-of-session when sampler is running");
 
-  for (;;) {
-    // This block skips entries until we find the start of the next sample.
-    // This is useful in three situations.
-    //
-    // - The circular buffer overwrites old entries, so when we start parsing
-    //   we might be in the middle of a sample, and we must skip forward to the
-    //   start of the next sample.
-    //
-    // - We skip samples that don't have an appropriate ThreadId or Time.
-    //
-    // - We skip range Pause, Resume, CollectionStart, Marker, Counter
-    //   and CollectionEnd entries between samples.
-    while (e.Has()) {
-      if (e.Get().IsThreadId()) {
+    EntryGetter e(*aReader);
+
+    for (;;) {
+      // This block skips entries until we find the start of the next sample.
+      // This is useful in three situations.
+      //
+      // - The circular buffer overwrites old entries, so when we start parsing
+      //   we might be in the middle of a sample, and we must skip forward to
+      //   the start of the next sample.
+      //
+      // - We skip samples that don't have an appropriate ThreadId or Time.
+      //
+      // - We skip range Pause, Resume, CollectionStart, Marker, Counter
+      //   and CollectionEnd entries between samples.
+      while (e.Has()) {
+        if (e.Get().IsThreadId()) {
+          break;
+        }
+        e.Next();
+      }
+
+      if (!e.Has()) {
         break;
+      }
+
+      if (e.Get().IsThreadId()) {
+        int threadId = e.Get().GetInt();
+        e.Next();
+
+        // Ignore samples that are for the wrong thread.
+        if (threadId != aThreadId) {
+          continue;
+        }
       } else {
-        e.Next();
+        // Due to the skip_to_next_sample block above, if we have an entry here
+        // it must be a ThreadId entry.
+        MOZ_CRASH();
       }
-    }
 
-    if (!e.Has()) {
-      break;
-    }
+      ProfileSample sample;
 
-    if (e.Get().IsThreadId()) {
-      int threadId = e.Get().GetInt();
-      e.Next();
+      auto ReadStack = [&](EntryGetter& e, uint64_t entryPosition,
+                           const Maybe<double>& unresponsiveDuration) {
+        UniqueStacks::StackKey stack =
+            aUniqueStacks.BeginStack(UniqueStacks::FrameKey("(root)"));
 
-      // Ignore samples that are for the wrong thread.
-      if (threadId != aThreadId) {
-        continue;
-      }
-    } else {
-      // Due to the skip_to_next_sample block above, if we have an entry here
-      // it must be a ThreadId entry.
-      MOZ_CRASH();
-    }
-
-    ProfileSample sample;
-
-    if (e.Has() && e.Get().IsTime()) {
-      sample.mTime = e.Get().GetDouble();
-      e.Next();
-
-      // Ignore samples that are too old.
-      if (sample.mTime < aSinceTime) {
-        continue;
-      }
-    } else {
-      ERROR_AND_CONTINUE("expected a Time entry");
-    }
-
-    UniqueStacks::StackKey stack =
-        aUniqueStacks.BeginStack(UniqueStacks::FrameKey("(root)"));
-
-    int numFrames = 0;
-    while (e.Has()) {
-      if (e.Get().IsNativeLeafAddr()) {
-        numFrames++;
-
-        void* pc = e.Get().GetPtr();
-        e.Next();
-
-        static const uint32_t BUF_SIZE = 256;
-        char buf[BUF_SIZE];
-
-        // Bug 753041: We need a double cast here to tell GCC that we don't
-        // want to sign extend 32-bit addresses starting with 0xFXXXXXX.
-        unsigned long long pcULL = (unsigned long long)(uintptr_t)pc;
-        SprintfLiteral(buf, "%#llx", pcULL);
-
-        // If the "MOZ_PROFILER_SYMBOLICATE" env-var is set, we add a local
-        // symbolication description to the PC address. This is off by default,
-        // and mainly intended for local development.
-        static const bool preSymbolicate = []() {
-          const char* symbolicate = getenv("MOZ_PROFILER_SYMBOLICATE");
-          return symbolicate && symbolicate[0] != '\0';
-        }();
-        if (preSymbolicate) {
-          MozCodeAddressDetails details;
-          if (MozDescribeCodeAddress(pc, &details)) {
-            // Replace \0 terminator with space.
-            const uint32_t pcLen = strlen(buf);
-            buf[pcLen] = ' ';
-            // Add description after space. Note: Using a frame number of 0,
-            // as using `numFrames` wouldn't help here, and would prevent
-            // combining same function calls that happen at different depths.
-            // TODO: Remove unsightly "#00: " if too annoying. :-)
-            MozFormatCodeAddressDetails(buf + pcLen + 1, BUF_SIZE - (pcLen + 1),
-                                        0, pc, &details);
-          }
-        }
-
-        stack = aUniqueStacks.AppendFrame(stack, UniqueStacks::FrameKey(buf));
-
-      } else if (e.Get().IsLabel()) {
-        numFrames++;
-
-        const char* label = e.Get().GetString();
-        e.Next();
-
-        using FrameFlags = js::ProfilingStackFrame::Flags;
-        uint32_t frameFlags = 0;
-        if (e.Has() && e.Get().IsFrameFlags()) {
-          frameFlags = uint32_t(e.Get().GetUint64());
-          e.Next();
-        }
-
-        bool relevantForJS = frameFlags & uint32_t(FrameFlags::RELEVANT_FOR_JS);
-
-        // Copy potential dynamic string fragments into dynStrBuf, so that
-        // dynStrBuf will then contain the entire dynamic string.
-        size_t i = 0;
-        dynStrBuf[0] = '\0';
+        int numFrames = 0;
         while (e.Has()) {
-          if (e.Get().IsDynamicStringFragment()) {
-            char chars[ProfileBufferEntry::kNumChars];
-            e.Get().CopyCharsInto(chars);
-            for (char c : chars) {
-              if (i < kMaxFrameKeyLength) {
-                dynStrBuf[i] = c;
-                i++;
+          if (e.Get().IsNativeLeafAddr()) {
+            numFrames++;
+
+            void* pc = e.Get().GetPtr();
+            e.Next();
+
+            nsAutoCString buf;
+
+            if (!aUniqueStacks.mCodeAddressService ||
+                !aUniqueStacks.mCodeAddressService->GetFunction(pc, buf) ||
+                buf.IsEmpty()) {
+              buf.AppendASCII("0x");
+              // `AppendInt` only knows `uint32_t` or `uint64_t`, but because
+              // these are just aliases for *two* of (`unsigned`, `unsigned
+              // long`, and `unsigned long long`), a call with `uintptr_t` could
+              // use the third type and therefore would be ambiguous.
+              // So we want to force using exactly `uint32_t` or `uint64_t`,
+              // whichever matches the size of `uintptr_t`.
+              // (The outer cast to `uint` should then be a no-op.)
+              using uint =
+                  std::conditional_t<sizeof(uintptr_t) <= sizeof(uint32_t),
+                                     uint32_t, uint64_t>;
+              buf.AppendInt(static_cast<uint>(reinterpret_cast<uintptr_t>(pc)),
+                            16);
+            }
+
+            stack = aUniqueStacks.AppendFrame(
+                stack, UniqueStacks::FrameKey(buf.get()));
+
+          } else if (e.Get().IsLabel()) {
+            numFrames++;
+
+            const char* label = e.Get().GetString();
+            e.Next();
+
+            using FrameFlags = js::ProfilingStackFrame::Flags;
+            uint32_t frameFlags = 0;
+            if (e.Has() && e.Get().IsFrameFlags()) {
+              frameFlags = uint32_t(e.Get().GetUint64());
+              e.Next();
+            }
+
+            bool relevantForJS =
+                frameFlags & uint32_t(FrameFlags::RELEVANT_FOR_JS);
+
+            // Copy potential dynamic string fragments into dynStrBuf, so that
+            // dynStrBuf will then contain the entire dynamic string.
+            size_t i = 0;
+            dynStrBuf[0] = '\0';
+            while (e.Has()) {
+              if (e.Get().IsDynamicStringFragment()) {
+                char chars[ProfileBufferEntry::kNumChars];
+                e.Get().CopyCharsInto(chars);
+                for (char c : chars) {
+                  if (i < kMaxFrameKeyLength) {
+                    dynStrBuf[i] = c;
+                    i++;
+                  }
+                }
+                e.Next();
+              } else {
+                break;
               }
             }
+            dynStrBuf[kMaxFrameKeyLength - 1] = '\0';
+            bool hasDynamicString = (i != 0);
+
+            nsAutoCStringN<1024> frameLabel;
+            if (label[0] != '\0' && hasDynamicString) {
+              if (frameFlags & uint32_t(FrameFlags::STRING_TEMPLATE_METHOD)) {
+                frameLabel.AppendPrintf("%s.%s", label, dynStrBuf.get());
+              } else if (frameFlags &
+                         uint32_t(FrameFlags::STRING_TEMPLATE_GETTER)) {
+                frameLabel.AppendPrintf("get %s.%s", label, dynStrBuf.get());
+              } else if (frameFlags &
+                         uint32_t(FrameFlags::STRING_TEMPLATE_SETTER)) {
+                frameLabel.AppendPrintf("set %s.%s", label, dynStrBuf.get());
+              } else {
+                frameLabel.AppendPrintf("%s %s", label, dynStrBuf.get());
+              }
+            } else if (hasDynamicString) {
+              frameLabel.Append(dynStrBuf.get());
+            } else {
+              frameLabel.Append(label);
+            }
+
+            Maybe<unsigned> line;
+            if (e.Has() && e.Get().IsLineNumber()) {
+              line = Some(unsigned(e.Get().GetInt()));
+              e.Next();
+            }
+
+            Maybe<unsigned> column;
+            if (e.Has() && e.Get().IsColumnNumber()) {
+              column = Some(unsigned(e.Get().GetInt()));
+              e.Next();
+            }
+
+            Maybe<JS::ProfilingCategoryPair> categoryPair;
+            if (e.Has() && e.Get().IsCategoryPair()) {
+              categoryPair =
+                  Some(JS::ProfilingCategoryPair(uint32_t(e.Get().GetInt())));
+              e.Next();
+            }
+
+            stack = aUniqueStacks.AppendFrame(
+                stack,
+                UniqueStacks::FrameKey(std::move(frameLabel), relevantForJS,
+                                       line, column, categoryPair));
+
+          } else if (e.Get().IsJitReturnAddr()) {
+            numFrames++;
+
+            // A JIT frame may expand to multiple frames due to inlining.
+            void* pc = e.Get().GetPtr();
+            const Maybe<Vector<UniqueStacks::FrameKey>>& frameKeys =
+                aUniqueStacks.LookupFramesForJITAddressFromBufferPos(
+                    pc, entryPosition ? entryPosition : e.CurPos());
+            MOZ_RELEASE_ASSERT(
+                frameKeys,
+                "Attempting to stream samples for a buffer range "
+                "for which we don't have JITFrameInfo?");
+            for (const UniqueStacks::FrameKey& frameKey : *frameKeys) {
+              stack = aUniqueStacks.AppendFrame(stack, frameKey);
+            }
+
             e.Next();
+
           } else {
             break;
           }
         }
-        dynStrBuf[kMaxFrameKeyLength - 1] = '\0';
-        bool hasDynamicString = (i != 0);
 
-        nsCString frameLabel;
-        if (label[0] != '\0' && hasDynamicString) {
-          if (frameFlags & uint32_t(FrameFlags::STRING_TEMPLATE_METHOD)) {
-            frameLabel.AppendPrintf("%s.%s", label, dynStrBuf.get());
-          } else if (frameFlags &
-                     uint32_t(FrameFlags::STRING_TEMPLATE_GETTER)) {
-            frameLabel.AppendPrintf("get %s.%s", label, dynStrBuf.get());
-          } else if (frameFlags &
-                     uint32_t(FrameFlags::STRING_TEMPLATE_SETTER)) {
-            frameLabel.AppendPrintf("set %s.%s", label, dynStrBuf.get());
-          } else {
-            frameLabel.AppendPrintf("%s %s", label, dynStrBuf.get());
+        if (numFrames == 0) {
+          // It is possible to have empty stacks if native stackwalking is
+          // disabled. Skip samples with empty stacks. (See Bug 1497985).
+          // Thus, don't use ERROR_AND_CONTINUE, but just continue by returning
+          // from this lambda.
+          return;
+        }
+
+        sample.mStack = aUniqueStacks.GetOrAddStackIndex(stack);
+
+        if (unresponsiveDuration.isSome()) {
+          sample.mResponsiveness = unresponsiveDuration;
+        }
+
+        WriteSample(aWriter, *aUniqueStacks.mUniqueStrings, sample);
+      };  // End of `ReadStack(EntryGetter&)` lambda.
+
+      if (e.Has() && e.Get().IsTime()) {
+        sample.mTime = e.Get().GetDouble();
+        e.Next();
+
+        // Ignore samples that are too old.
+        if (sample.mTime < aSinceTime) {
+          continue;
+        }
+
+        ReadStack(e, 0, Nothing{});
+      } else if (e.Has() && e.Get().IsTimeBeforeCompactStack()) {
+        sample.mTime = e.Get().GetDouble();
+
+        // Ignore samples that are too old.
+        if (sample.mTime < aSinceTime) {
+          e.Next();
+          continue;
+        }
+
+        Maybe<double> unresponsiveDuration;
+
+        BlocksRingBuffer::BlockIterator it = e.Iterator();
+        for (;;) {
+          ++it;
+          if (it.IsAtEnd()) {
+            break;
           }
-        } else if (hasDynamicString) {
-          frameLabel.Append(dynStrBuf.get());
-        } else {
-          frameLabel.Append(label);
-        }
+          BlocksRingBuffer::EntryReader er = *it;
+          ProfileBufferEntry::Kind kind =
+              er.ReadObject<ProfileBufferEntry::Kind>();
 
-        Maybe<unsigned> line;
-        if (e.Has() && e.Get().IsLineNumber()) {
-          line = Some(unsigned(e.Get().GetInt()));
-          e.Next();
-        }
+          // There may be an UnresponsiveDurationMs before the CompactStack.
+          if (kind == ProfileBufferEntry::Kind::UnresponsiveDurationMs) {
+            unresponsiveDuration = Some(er.ReadObject<double>());
+            continue;
+          }
 
-        Maybe<unsigned> column;
-        if (e.Has() && e.Get().IsColumnNumber()) {
-          column = Some(unsigned(e.Get().GetInt()));
-          e.Next();
-        }
+          if (kind == ProfileBufferEntry::Kind::CompactStack) {
+            BlocksRingBuffer tempBuffer(
+                BlocksRingBuffer::ThreadSafety::WithoutMutex,
+                mWorkerBuffer.get(), WorkerBufferBytes);
+            er.ReadIntoObject(tempBuffer);
+            tempBuffer.Read([&](BlocksRingBuffer::Reader* aReader) {
+              MOZ_ASSERT(aReader,
+                         "Local BlocksRingBuffer cannot be out-of-session");
+              EntryGetter stackEntryGetter(*aReader);
+              if (stackEntryGetter.Has()) {
+                ReadStack(stackEntryGetter,
+                          er.CurrentBlockIndex().ConvertToU64(),
+                          unresponsiveDuration);
+              }
+            });
+            break;
+          }
 
-        Maybe<JS::ProfilingCategoryPair> categoryPair;
-        if (e.Has() && e.Get().IsCategoryPair()) {
-          categoryPair =
-              Some(JS::ProfilingCategoryPair(uint32_t(e.Get().GetInt())));
-          e.Next();
-        }
-
-        stack = aUniqueStacks.AppendFrame(
-            stack, UniqueStacks::FrameKey(std::move(frameLabel), relevantForJS,
-                                          line, column, categoryPair));
-
-      } else if (e.Get().IsJitReturnAddr()) {
-        numFrames++;
-
-        // A JIT frame may expand to multiple frames due to inlining.
-        void* pc = e.Get().GetPtr();
-        const Maybe<Vector<UniqueStacks::FrameKey>>& frameKeys =
-            aUniqueStacks.LookupFramesForJITAddressFromBufferPos(pc,
-                                                                 e.CurPos());
-        MOZ_RELEASE_ASSERT(frameKeys,
-                           "Attempting to stream samples for a buffer range "
-                           "for which we don't have JITFrameInfo?");
-        for (const UniqueStacks::FrameKey& frameKey : *frameKeys) {
-          stack = aUniqueStacks.AppendFrame(stack, frameKey);
+          MOZ_ASSERT(kind >= ProfileBufferEntry::Kind::LEGACY_LIMIT,
+                     "There should be no legacy entries between "
+                     "TimeBeforeCompactStack and CompactStack");
         }
 
         e.Next();
-
       } else {
-        break;
+        ERROR_AND_CONTINUE("expected a Time entry");
       }
     }
-
-    if (numFrames == 0) {
-      // It is possible to have empty stacks if native stackwalking is
-      // disabled. Skip samples with empty stacks. (See Bug 1497985).
-      // Thus, don't use ERROR_AND_CONTINUE, but just continue.
-      continue;
-    }
-
-    sample.mStack = aUniqueStacks.GetOrAddStackIndex(stack);
-
-    // Skip over the markers. We process them in StreamMarkersToJSON().
-    while (e.Has()) {
-      if (e.Get().IsMarker()) {
-        e.Next();
-      } else {
-        break;
-      }
-    }
-
-    if (e.Has() && e.Get().IsResponsiveness()) {
-      sample.mResponsiveness = Some(e.Get().GetDouble());
-      e.Next();
-    }
-
-    if (e.Has() && e.Get().IsResidentMemory()) {
-      sample.mRSS = Some(e.Get().GetDouble());
-      e.Next();
-    }
-
-    if (e.Has() && e.Get().IsUnsharedMemory()) {
-      sample.mUSS = Some(e.Get().GetDouble());
-      e.Next();
-    }
-
-    WriteSample(aWriter, *aUniqueStacks.mUniqueStrings, sample);
-  }
+  });
 }
 
 void ProfileBuffer::AddJITInfoForRange(uint64_t aRangeStart, int aThreadId,
@@ -981,39 +1042,88 @@ void ProfileBuffer::AddJITInfoForRange(uint64_t aRangeStart, int aThreadId,
   // We can only process JitReturnAddr entries if we have a JSContext.
   MOZ_RELEASE_ASSERT(aContext);
 
-  aRangeStart = std::max(aRangeStart, mRangeStart);
+  aRangeStart = std::max(aRangeStart, BufferRangeStart());
   aJITFrameInfo.AddInfoForRange(
-      aRangeStart, mRangeEnd, aContext,
+      aRangeStart, BufferRangeEnd(), aContext,
       [&](const std::function<void(void*)>& aJITAddressConsumer) {
         // Find all JitReturnAddr entries in the given range for the given
         // thread, and call aJITAddressConsumer with those addresses.
 
-        EntryGetter e(*this, aRangeStart);
-        while (true) {
-          // Advance to the next ThreadId entry.
-          while (e.Has() && !e.Get().IsThreadId()) {
-            e.Next();
-          }
-          if (!e.Has()) {
-            break;
-          }
+        mEntries.Read([&](BlocksRingBuffer::Reader* aReader) {
+          MOZ_ASSERT(aReader,
+                     "BlocksRingBuffer cannot be out-of-session when sampler "
+                     "is running");
 
-          MOZ_ASSERT(e.Get().IsThreadId());
-          int threadId = e.Get().GetInt();
-          e.Next();
+          EntryGetter e(*aReader, aRangeStart);
 
-          // Ignore samples that are for a different thread.
-          if (threadId != aThreadId) {
-            continue;
-          }
-
-          while (e.Has() && !e.Get().IsThreadId()) {
-            if (e.Get().IsJitReturnAddr()) {
-              aJITAddressConsumer(e.Get().GetPtr());
+          while (true) {
+            // Advance to the next ThreadId entry.
+            while (e.Has() && !e.Get().IsThreadId()) {
+              e.Next();
             }
+            if (!e.Has()) {
+              break;
+            }
+
+            MOZ_ASSERT(e.Get().IsThreadId());
+            int threadId = e.Get().GetInt();
             e.Next();
+
+            // Ignore samples that are for a different thread.
+            if (threadId != aThreadId) {
+              continue;
+            }
+
+            if (e.Has() && e.Get().IsTime()) {
+              // Legacy stack.
+              e.Next();
+              while (e.Has() && !e.Get().IsThreadId()) {
+                if (e.Get().IsJitReturnAddr()) {
+                  aJITAddressConsumer(e.Get().GetPtr());
+                }
+                e.Next();
+              }
+            } else if (e.Has() && e.Get().IsTimeBeforeCompactStack()) {
+              // Compact stack.
+              BlocksRingBuffer::BlockIterator it = e.Iterator();
+              for (;;) {
+                ++it;
+                if (it.IsAtEnd()) {
+                  break;
+                }
+                BlocksRingBuffer::EntryReader er = *it;
+                ProfileBufferEntry::Kind kind =
+                    er.ReadObject<ProfileBufferEntry::Kind>();
+                if (kind == ProfileBufferEntry::Kind::CompactStack) {
+                  BlocksRingBuffer tempBuffer(
+                      BlocksRingBuffer::ThreadSafety::WithoutMutex,
+                      mWorkerBuffer.get(), WorkerBufferBytes);
+                  er.ReadIntoObject(tempBuffer);
+                  tempBuffer.Read([&](BlocksRingBuffer::Reader* aReader) {
+                    MOZ_ASSERT(
+                        aReader,
+                        "Local BlocksRingBuffer cannot be out-of-session");
+                    EntryGetter stackEntryGetter(*aReader);
+                    while (stackEntryGetter.Has()) {
+                      if (stackEntryGetter.Get().IsJitReturnAddr()) {
+                        aJITAddressConsumer(stackEntryGetter.Get().GetPtr());
+                      }
+                      stackEntryGetter.Next();
+                    }
+                  });
+                  break;
+                }
+                MOZ_ASSERT(kind >= ProfileBufferEntry::Kind::LEGACY_LIMIT,
+                           "There should be no legacy entries between "
+                           "TimeBeforeCompactStack and CompactStack");
+              }
+
+              e.Next();
+            } else {
+              ERROR_AND_CONTINUE("expected a Time entry");
+            }
           }
-        }
+        });
       });
 }
 
@@ -1022,156 +1132,163 @@ void ProfileBuffer::StreamMarkersToJSON(SpliceableJSONWriter& aWriter,
                                         const TimeStamp& aProcessStartTime,
                                         double aSinceTime,
                                         UniqueStacks& aUniqueStacks) const {
-  EntryGetter e(*this);
+  mEntries.ReadEach([&](BlocksRingBuffer::EntryReader& aER) {
+    auto type = static_cast<ProfileBufferEntry::Kind>(
+        aER.ReadObject<ProfileBufferEntry::KindUnderlyingType>());
+    MOZ_ASSERT(static_cast<ProfileBufferEntry::KindUnderlyingType>(type) <
+               static_cast<ProfileBufferEntry::KindUnderlyingType>(
+                   ProfileBufferEntry::Kind::MODERN_LIMIT));
+    if (type == ProfileBufferEntry::Kind::MarkerData &&
+        aER.ReadObject<int>() == aThreadId) {
+      // Schema:
+      //   [name, time, category, data]
 
-  // Stream all markers whose threadId matches aThreadId. We skip other entries,
-  // because we process them in StreamSamplesToJSON().
-  //
-  // NOTE: The ThreadId of a marker is determined by its GetThreadId() method,
-  // rather than ThreadId buffer entries, as markers can be added outside of
-  // samples.
-  while (e.Has()) {
-    if (e.Get().IsMarker()) {
-      const ProfilerMarker* marker = e.Get().GetMarker();
-      if (marker->GetTime() >= aSinceTime &&
-          marker->GetThreadId() == aThreadId) {
-        marker->StreamJSON(aWriter, aProcessStartTime, aUniqueStacks);
+      aWriter.StartArrayElement();
+      {
+        std::string name = aER.ReadObject<std::string>();
+        const JS::ProfilingCategoryPairInfo& info =
+            GetProfilingCategoryPairInfo(static_cast<JS::ProfilingCategoryPair>(
+                aER.ReadObject<uint32_t>()));
+        auto payload = aER.ReadObject<UniquePtr<ProfilerMarkerPayload>>();
+        double time = aER.ReadObject<double>();
+        MOZ_ASSERT(aER.IndexInEntry() == aER.EntryBytes());
+
+        aUniqueStacks.mUniqueStrings->WriteElement(aWriter, name.c_str());
+        aWriter.DoubleElement(time);
+        aWriter.IntElement(unsigned(info.mCategory));
+        if (payload) {
+          aWriter.StartObjectElement(SpliceableJSONWriter::SingleLineStyle);
+          { payload->StreamPayload(aWriter, aProcessStartTime, aUniqueStacks); }
+          aWriter.EndObject();
+        }
       }
+      aWriter.EndArray();
     }
-    e.Next();
-  }
+  });
 }
 
 void ProfileBuffer::StreamProfilerOverheadToJSON(
     SpliceableJSONWriter& aWriter, const TimeStamp& aProcessStartTime,
     double aSinceTime) const {
-  enum Schema : uint32_t {
-    TIME = 0,
-    LOCKING = 1,
-    MARKER_CLEANING = 2,
-    COUNTERS = 3,
-    THREADS = 4
-  };
+  mEntries.Read([&](BlocksRingBuffer::Reader* aReader) {
+    MOZ_ASSERT(
+        aReader,
+        "BlocksRingBuffer cannot be out-of-session when sampler is running");
 
-  EntryGetter e(*this);
+    EntryGetter e(*aReader);
 
-  aWriter.StartObjectProperty("profilerOverhead_UNSTABLE");
-  // Stream all sampling overhead data. We skip other entries, because we
-  // process them in StreamSamplesToJSON()/etc.
-  {
-    JSONSchemaWriter schema(aWriter);
-    schema.WriteField("time");
-    schema.WriteField("locking");
-    schema.WriteField("expiredMarkerCleaning");
-    schema.WriteField("counters");
-    schema.WriteField("threads");
-  }
+    enum Schema : uint32_t {
+      TIME = 0,
+      LOCKING = 1,
+      MARKER_CLEANING = 2,
+      COUNTERS = 3,
+      THREADS = 4
+    };
 
-  aWriter.StartArrayProperty("data");
-  double firstTime = 0.0;
-  double lastTime = 0.0;
-  struct Stats {
-    unsigned n = 0;
-    double sum = 0;
-    double min = std::numeric_limits<double>::max();
-    double max = 0;
-    void Count(double v) {
-      ++n;
-      sum += v;
-      if (v < min) {
-        min = v;
-      }
-      if (v > max) {
-        max = v;
-      }
+    aWriter.StartObjectProperty("profilerOverhead");
+    aWriter.StartObjectProperty("samples");
+    // Stream all sampling overhead data. We skip other entries, because we
+    // process them in StreamSamplesToJSON()/etc.
+    {
+      JSONSchemaWriter schema(aWriter);
+      schema.WriteField("time");
+      schema.WriteField("locking");
+      schema.WriteField("expiredMarkerCleaning");
+      schema.WriteField("counters");
+      schema.WriteField("threads");
     }
-  };
-  Stats intervals, overheads, lockings, cleanings, counters, threads;
-  while (e.Has()) {
-    // valid sequence: ProfilerOverheadTime, ProfilerOverheadDuration * 4
-    if (e.Get().IsProfilerOverheadTime()) {
-      double time = e.Get().GetDouble();
-      if (time >= aSinceTime) {
-        e.Next();
-        if (!e.Has() || !e.Get().IsProfilerOverheadDuration()) {
-          ERROR_AND_CONTINUE(
-              "expected a ProfilerOverheadDuration entry after "
-              "ProfilerOverheadTime");
-        }
-        double locking = e.Get().GetDouble();
-        e.Next();
-        if (!e.Has() || !e.Get().IsProfilerOverheadDuration()) {
-          ERROR_AND_CONTINUE(
-              "expected a ProfilerOverheadDuration entry after "
-              "ProfilerOverheadTime,ProfilerOverheadDuration");
-        }
-        double cleaning = e.Get().GetDouble();
-        e.Next();
-        if (!e.Has() || !e.Get().IsProfilerOverheadDuration()) {
-          ERROR_AND_CONTINUE(
-              "expected a ProfilerOverheadDuration entry after "
-              "ProfilerOverheadTime,ProfilerOverheadDuration*2");
-        }
-        double counter = e.Get().GetDouble();
-        e.Next();
-        if (!e.Has() || !e.Get().IsProfilerOverheadDuration()) {
-          ERROR_AND_CONTINUE(
-              "expected a ProfilerOverheadDuration entry after "
-              "ProfilerOverheadTime,ProfilerOverheadDuration*3");
-        }
-        double thread = e.Get().GetDouble();
 
-        if (firstTime == 0.0) {
-          firstTime = time;
-        } else {
-          // Note that we'll have 1 fewer interval than other numbers (because
-          // we need both ends of an interval to know its duration). The final
-          // difference should be insignificant over the expected many thousands
-          // of iterations.
-          intervals.Count(time - lastTime);
-        }
-        lastTime = time;
-        overheads.Count(locking + cleaning + counter + thread);
-        lockings.Count(locking);
-        cleanings.Count(cleaning);
-        counters.Count(counter);
-        threads.Count(thread);
+    aWriter.StartArrayProperty("data");
+    double firstTime = 0.0;
+    double lastTime = 0.0;
+    ProfilerStats intervals, overheads, lockings, cleanings, counters, threads;
+    while (e.Has()) {
+      // valid sequence: ProfilerOverheadTime, ProfilerOverheadDuration * 4
+      if (e.Get().IsProfilerOverheadTime()) {
+        double time = e.Get().GetDouble();
+        if (time >= aSinceTime) {
+          e.Next();
+          if (!e.Has() || !e.Get().IsProfilerOverheadDuration()) {
+            ERROR_AND_CONTINUE(
+                "expected a ProfilerOverheadDuration entry after "
+                "ProfilerOverheadTime");
+          }
+          double locking = e.Get().GetDouble();
+          e.Next();
+          if (!e.Has() || !e.Get().IsProfilerOverheadDuration()) {
+            ERROR_AND_CONTINUE(
+                "expected a ProfilerOverheadDuration entry after "
+                "ProfilerOverheadTime,ProfilerOverheadDuration");
+          }
+          double cleaning = e.Get().GetDouble();
+          e.Next();
+          if (!e.Has() || !e.Get().IsProfilerOverheadDuration()) {
+            ERROR_AND_CONTINUE(
+                "expected a ProfilerOverheadDuration entry after "
+                "ProfilerOverheadTime,ProfilerOverheadDuration*2");
+          }
+          double counter = e.Get().GetDouble();
+          e.Next();
+          if (!e.Has() || !e.Get().IsProfilerOverheadDuration()) {
+            ERROR_AND_CONTINUE(
+                "expected a ProfilerOverheadDuration entry after "
+                "ProfilerOverheadTime,ProfilerOverheadDuration*3");
+          }
+          double thread = e.Get().GetDouble();
 
-        AutoArraySchemaWriter writer(aWriter);
-        writer.DoubleElement(TIME, time);
-        writer.DoubleElement(LOCKING, locking);
-        writer.DoubleElement(MARKER_CLEANING, cleaning);
-        writer.DoubleElement(COUNTERS, counter);
-        writer.DoubleElement(THREADS, thread);
+          if (firstTime == 0.0) {
+            firstTime = time;
+          } else {
+            // Note that we'll have 1 fewer interval than other numbers (because
+            // we need both ends of an interval to know its duration). The final
+            // difference should be insignificant over the expected many
+            // thousands of iterations.
+            intervals.Count(time - lastTime);
+          }
+          lastTime = time;
+          overheads.Count(locking + cleaning + counter + thread);
+          lockings.Count(locking);
+          cleanings.Count(cleaning);
+          counters.Count(counter);
+          threads.Count(thread);
+
+          AutoArraySchemaWriter writer(aWriter);
+          writer.DoubleElement(TIME, time);
+          writer.DoubleElement(LOCKING, locking);
+          writer.DoubleElement(MARKER_CLEANING, cleaning);
+          writer.DoubleElement(COUNTERS, counter);
+          writer.DoubleElement(THREADS, thread);
+        }
       }
+      e.Next();
     }
-    e.Next();
-  }
-  aWriter.EndArray();  // data
+    aWriter.EndArray();   // data
+    aWriter.EndObject();  // samples
 
-  // Only output statistics if there is at least one full interval (and
-  // therefore at least two samplings.)
-  if (intervals.n > 0) {
-    aWriter.StartObjectProperty("statistics");
-    aWriter.DoubleProperty("profiledDuration", lastTime - firstTime);
-    aWriter.IntProperty("samplingCount", overheads.n);
-    aWriter.DoubleProperty("overheadDurations", overheads.sum);
-    aWriter.DoubleProperty("overheadPercentage",
-                           overheads.sum / (lastTime - firstTime));
+    // Only output statistics if there is at least one full interval (and
+    // therefore at least two samplings.)
+    if (intervals.n > 0) {
+      aWriter.StartObjectProperty("statistics");
+      aWriter.DoubleProperty("profiledDuration", lastTime - firstTime);
+      aWriter.IntProperty("samplingCount", overheads.n);
+      aWriter.DoubleProperty("overheadDurations", overheads.sum);
+      aWriter.DoubleProperty("overheadPercentage",
+                             overheads.sum / (lastTime - firstTime));
 #define PROFILER_STATS(name, var)                           \
   aWriter.DoubleProperty("mean" name, (var).sum / (var).n); \
   aWriter.DoubleProperty("min" name, (var).min);            \
   aWriter.DoubleProperty("max" name, (var).max);
-    PROFILER_STATS("Interval", intervals);
-    PROFILER_STATS("Overhead", overheads);
-    PROFILER_STATS("Lockings", lockings);
-    PROFILER_STATS("Cleaning", cleanings);
-    PROFILER_STATS("Counter", counters);
-    PROFILER_STATS("Thread", threads);
+      PROFILER_STATS("Interval", intervals);
+      PROFILER_STATS("Overhead", overheads);
+      PROFILER_STATS("Lockings", lockings);
+      PROFILER_STATS("Cleaning", cleanings);
+      PROFILER_STATS("Counter", counters);
+      PROFILER_STATS("Thread", threads);
 #undef PROFILER_STATS
-    aWriter.EndObject();  // statistics
-  }
-  aWriter.EndObject();  // profilerOverhead
+      aWriter.EndObject();  // statistics
+    }
+    aWriter.EndObject();  // profilerOverhead
+  });
 }
 
 struct CounterKeyedSample {
@@ -1206,213 +1323,160 @@ void ProfileBuffer::StreamCountersToJSON(SpliceableJSONWriter& aWriter,
   // error indicates a bug in the ProfileBuffer writing or the parser itself,
   // or possibly flaky hardware.
 
-  EntryGetter e(*this);
-  enum Schema : uint32_t { TIME = 0, NUMBER = 1, COUNT = 2 };
+  mEntries.Read([&](BlocksRingBuffer::Reader* aReader) {
+    MOZ_ASSERT(
+        aReader,
+        "BlocksRingBuffer cannot be out-of-session when sampler is running");
 
-  // Stream all counters. We skip other entries, because we process them in
-  // StreamSamplesToJSON()/etc.
-  //
-  // Valid sequence in the buffer:
-  // CounterID
-  // Time
-  // ( CounterKey Count Number? )*
-  //
-  // And the JSON (example):
-  // "counters": {
-  //  "name": "malloc",
-  //  "category": "Memory",
-  //  "description": "Amount of allocated memory",
-  //  "sample_groups": {
-  //   "id": 0,
-  //   "samples": {
-  //    "schema": {"time": 0, "number": 1, "count": 2},
-  //    "data": [
-  //     [
-  //      16117.033968000002,
-  //      2446216,
-  //      6801320
-  //     ],
-  //     [
-  //      16118.037638,
-  //      2446216,
-  //      6801320
-  //     ],
-  //    ],
-  //   }
-  //  }
-  // },
+    EntryGetter e(*aReader);
 
-  // Build the map of counters and populate it
-  HashMap<void*, CounterMap> counters;
+    enum Schema : uint32_t { TIME = 0, NUMBER = 1, COUNT = 2 };
 
-  while (e.Has()) {
-    // skip all non-Counters, including if we start in the middle of a counter
-    if (e.Get().IsCounterId()) {
-      void* id = e.Get().GetPtr();
-      CounterMap& counter = LookupOrAdd(counters, id);
-      e.Next();
-      if (!e.Has() || !e.Get().IsTime()) {
-        ERROR_AND_CONTINUE("expected a Time entry");
-      }
-      double time = e.Get().GetDouble();
-      if (time >= aSinceTime) {
+    // Stream all counters. We skip other entries, because we process them in
+    // StreamSamplesToJSON()/etc.
+    //
+    // Valid sequence in the buffer:
+    // CounterID
+    // Time
+    // ( CounterKey Count Number? )*
+    //
+    // And the JSON (example):
+    // "counters": {
+    //  "name": "malloc",
+    //  "category": "Memory",
+    //  "description": "Amount of allocated memory",
+    //  "sample_groups": {
+    //   "id": 0,
+    //   "samples": {
+    //    "schema": {"time": 0, "number": 1, "count": 2},
+    //    "data": [
+    //     [
+    //      16117.033968000002,
+    //      2446216,
+    //      6801320
+    //     ],
+    //     [
+    //      16118.037638,
+    //      2446216,
+    //      6801320
+    //     ],
+    //    ],
+    //   }
+    //  }
+    // },
+
+    // Build the map of counters and populate it
+    HashMap<void*, CounterMap> counters;
+
+    while (e.Has()) {
+      // skip all non-Counters, including if we start in the middle of a counter
+      if (e.Get().IsCounterId()) {
+        void* id = e.Get().GetPtr();
+        CounterMap& counter = LookupOrAdd(counters, id);
         e.Next();
-        while (e.Has() && e.Get().IsCounterKey()) {
-          uint64_t key = e.Get().GetUint64();
-          CounterKeyedSamples& data = LookupOrAdd(counter, key);
-          e.Next();
-          if (!e.Has() || !e.Get().IsCount()) {
-            ERROR_AND_CONTINUE("expected a Count entry");
-          }
-          int64_t count = e.Get().GetUint64();
-          e.Next();
-          uint64_t number;
-          if (!e.Has() || !e.Get().IsNumber()) {
-            number = 0;
-          } else {
-            number = e.Get().GetInt64();
-          }
-          CounterKeyedSample sample = {time, number, count};
-          MOZ_RELEASE_ASSERT(data.append(sample));
-        }
-      } else {
-        // skip counter sample - only need to skip the initial counter
-        // id, then let the loop at the top skip the rest
-      }
-    }
-    e.Next();
-  }
-  // we have a map of a map of counter entries; dump them to JSON
-  if (counters.count() == 0) {
-    return;
-  }
-
-  aWriter.StartArrayProperty("counters");
-  for (auto iter = counters.iter(); !iter.done(); iter.next()) {
-    CounterMap& counter = iter.get().value();
-    const BaseProfilerCount* base_counter =
-        static_cast<const BaseProfilerCount*>(iter.get().key());
-
-    aWriter.Start();
-    aWriter.StringProperty("name", base_counter->mLabel);
-    aWriter.StringProperty("category", base_counter->mCategory);
-    aWriter.StringProperty("description", base_counter->mDescription);
-
-    aWriter.StartObjectProperty("sample_groups");
-    for (auto counter_iter = counter.iter(); !counter_iter.done();
-         counter_iter.next()) {
-      CounterKeyedSamples& samples = counter_iter.get().value();
-      uint64_t key = counter_iter.get().key();
-
-      size_t size = samples.length();
-      if (size == 0) {
-        continue;
-      }
-      aWriter.IntProperty("id", static_cast<int64_t>(key));
-      aWriter.StartObjectProperty("samples");
-      {
-        // XXX Can we assume a missing count means 0?
-        JSONSchemaWriter schema(aWriter);
-        schema.WriteField("time");
-        schema.WriteField("number");
-        schema.WriteField("count");
-      }
-
-      aWriter.StartArrayProperty("data");
-      uint64_t previousNumber = 0;
-      int64_t previousCount = 0;
-      for (size_t i = 0; i < size; i++) {
-        // Encode as deltas, and only encode if different than the last sample
-        if (i == 0 || samples[i].mNumber != previousNumber ||
-            samples[i].mCount != previousCount) {
-          if (i != 0 && samples[i].mTime >= samples[i - 1].mTime) {
-            MOZ_LOG(sFuzzyfoxLog, mozilla::LogLevel::Error,
-                    ("Fuzzyfox Profiler Assertion: %f >= %f", samples[i].mTime,
-                     samples[i - 1].mTime));
-          }
-          MOZ_ASSERT(i == 0 || samples[i].mTime >= samples[i - 1].mTime);
-          MOZ_ASSERT(samples[i].mNumber >= previousNumber);
-          MOZ_ASSERT(samples[i].mNumber - previousNumber <=
-                     uint64_t(std::numeric_limits<int64_t>::max()));
-
-          AutoArraySchemaWriter writer(aWriter);
-          writer.DoubleElement(TIME, samples[i].mTime);
-          writer.IntElement(NUMBER, static_cast<int64_t>(samples[i].mNumber -
-                                                         previousNumber));
-          writer.IntElement(COUNT, samples[i].mCount - previousCount);
-          previousNumber = samples[i].mNumber;
-          previousCount = samples[i].mCount;
-        }
-      }
-      aWriter.EndArray();   // data
-      aWriter.EndObject();  // samples
-    }
-    aWriter.EndObject();  // sample groups
-    aWriter.End();        // for each counter
-  }
-  aWriter.EndArray();  // counters
-}
-
-void ProfileBuffer::StreamMemoryToJSON(SpliceableJSONWriter& aWriter,
-                                       const TimeStamp& aProcessStartTime,
-                                       double aSinceTime) const {
-  enum Schema : uint32_t { TIME = 0, RSS = 1, USS = 2 };
-
-  EntryGetter e(*this);
-
-  aWriter.StartObjectProperty("memory");
-  // Stream all memory (rss/uss) data. We skip other entries, because we
-  // process them in StreamSamplesToJSON()/etc.
-  aWriter.IntProperty("initial_heap", 0);  // XXX FIX
-  aWriter.StartObjectProperty("samples");
-  {
-    JSONSchemaWriter schema(aWriter);
-    schema.WriteField("time");
-    schema.WriteField("rss");
-    schema.WriteField("uss");
-  }
-
-  aWriter.StartArrayProperty("data");
-  int64_t previous_rss = 0;
-  int64_t previous_uss = 0;
-  while (e.Has()) {
-    // valid sequence: Resident, Unshared?, Time
-    if (e.Get().IsResidentMemory()) {
-      int64_t rss = e.Get().GetInt64();
-      int64_t uss = 0;
-      e.Next();
-      if (e.Has()) {
-        if (e.Get().IsUnsharedMemory()) {
-          uss = e.Get().GetDouble();
-          e.Next();
-          if (!e.Has()) {
-            break;
-          }
-        }
-        if (e.Get().IsTime()) {
-          double time = e.Get().GetDouble();
-          if (time >= aSinceTime &&
-              (previous_rss != rss || previous_uss != uss)) {
-            AutoArraySchemaWriter writer(aWriter);
-            writer.DoubleElement(TIME, time);
-            writer.IntElement(RSS, rss);
-            if (uss != 0) {
-              writer.IntElement(USS, uss);
-            }
-            previous_rss = rss;
-            previous_uss = uss;
-          }
-        } else {
+        if (!e.Has() || !e.Get().IsTime()) {
           ERROR_AND_CONTINUE("expected a Time entry");
         }
+        double time = e.Get().GetDouble();
+        if (time >= aSinceTime) {
+          e.Next();
+          while (e.Has() && e.Get().IsCounterKey()) {
+            uint64_t key = e.Get().GetUint64();
+            CounterKeyedSamples& data = LookupOrAdd(counter, key);
+            e.Next();
+            if (!e.Has() || !e.Get().IsCount()) {
+              ERROR_AND_CONTINUE("expected a Count entry");
+            }
+            int64_t count = e.Get().GetUint64();
+            e.Next();
+            uint64_t number;
+            if (!e.Has() || !e.Get().IsNumber()) {
+              number = 0;
+            } else {
+              number = e.Get().GetInt64();
+            }
+            CounterKeyedSample sample = {time, number, count};
+            MOZ_RELEASE_ASSERT(data.append(sample));
+          }
+        } else {
+          // skip counter sample - only need to skip the initial counter
+          // id, then let the loop at the top skip the rest
+        }
       }
+      e.Next();
     }
-    e.Next();
-  }
-  aWriter.EndArray();   // data
-  aWriter.EndObject();  // samples
-  aWriter.EndObject();  // memory
+    // we have a map of a map of counter entries; dump them to JSON
+    if (counters.count() == 0) {
+      return;
+    }
+
+    aWriter.StartArrayProperty("counters");
+    for (auto iter = counters.iter(); !iter.done(); iter.next()) {
+      CounterMap& counter = iter.get().value();
+      const BaseProfilerCount* base_counter =
+          static_cast<const BaseProfilerCount*>(iter.get().key());
+
+      aWriter.Start();
+      aWriter.StringProperty("name", base_counter->mLabel);
+      aWriter.StringProperty("category", base_counter->mCategory);
+      aWriter.StringProperty("description", base_counter->mDescription);
+
+      aWriter.StartObjectProperty("sample_groups");
+      for (auto counter_iter = counter.iter(); !counter_iter.done();
+           counter_iter.next()) {
+        CounterKeyedSamples& samples = counter_iter.get().value();
+        uint64_t key = counter_iter.get().key();
+
+        size_t size = samples.length();
+        if (size == 0) {
+          continue;
+        }
+        aWriter.IntProperty("id", static_cast<int64_t>(key));
+        aWriter.StartObjectProperty("samples");
+        {
+          // XXX Can we assume a missing count means 0?
+          JSONSchemaWriter schema(aWriter);
+          schema.WriteField("time");
+          schema.WriteField("number");
+          schema.WriteField("count");
+        }
+
+        aWriter.StartArrayProperty("data");
+        uint64_t previousNumber = 0;
+        int64_t previousCount = 0;
+        for (size_t i = 0; i < size; i++) {
+          // Encode as deltas, and only encode if different than the last sample
+          if (i == 0 || samples[i].mNumber != previousNumber ||
+              samples[i].mCount != previousCount) {
+            if (i != 0 && samples[i].mTime >= samples[i - 1].mTime) {
+              MOZ_LOG(sFuzzyfoxLog, mozilla::LogLevel::Error,
+                      ("Fuzzyfox Profiler Assertion: %f >= %f",
+                       samples[i].mTime, samples[i - 1].mTime));
+            }
+            MOZ_ASSERT(i == 0 || samples[i].mTime >= samples[i - 1].mTime);
+            MOZ_ASSERT(samples[i].mNumber >= previousNumber);
+            MOZ_ASSERT(samples[i].mNumber - previousNumber <=
+                       uint64_t(std::numeric_limits<int64_t>::max()));
+
+            AutoArraySchemaWriter writer(aWriter);
+            writer.DoubleElement(TIME, samples[i].mTime);
+            writer.IntElement(NUMBER, static_cast<int64_t>(samples[i].mNumber -
+                                                           previousNumber));
+            writer.IntElement(COUNT, samples[i].mCount - previousCount);
+            previousNumber = samples[i].mNumber;
+            previousCount = samples[i].mCount;
+          }
+        }
+        aWriter.EndArray();   // data
+        aWriter.EndObject();  // samples
+      }
+      aWriter.EndObject();  // sample groups
+      aWriter.End();        // for each counter
+    }
+    aWriter.EndArray();  // counters
+  });
 }
+
 #undef ERROR_AND_CONTINUE
 
 static void AddPausedRange(SpliceableJSONWriter& aWriter, const char* aReason,
@@ -1435,180 +1499,267 @@ static void AddPausedRange(SpliceableJSONWriter& aWriter, const char* aReason,
 
 void ProfileBuffer::StreamPausedRangesToJSON(SpliceableJSONWriter& aWriter,
                                              double aSinceTime) const {
-  EntryGetter e(*this);
+  mEntries.Read([&](BlocksRingBuffer::Reader* aReader) {
+    MOZ_ASSERT(
+        aReader,
+        "BlocksRingBuffer cannot be out-of-session when sampler is running");
 
-  Maybe<double> currentPauseStartTime;
-  Maybe<double> currentCollectionStartTime;
+    EntryGetter e(*aReader);
 
-  while (e.Has()) {
-    if (e.Get().IsPause()) {
-      currentPauseStartTime = Some(e.Get().GetDouble());
-    } else if (e.Get().IsResume()) {
-      AddPausedRange(aWriter, "profiler-paused", currentPauseStartTime,
-                     Some(e.Get().GetDouble()));
-      currentPauseStartTime = Nothing();
-    } else if (e.Get().IsCollectionStart()) {
-      currentCollectionStartTime = Some(e.Get().GetDouble());
-    } else if (e.Get().IsCollectionEnd()) {
-      AddPausedRange(aWriter, "collecting", currentCollectionStartTime,
-                     Some(e.Get().GetDouble()));
-      currentCollectionStartTime = Nothing();
+    Maybe<double> currentPauseStartTime;
+    Maybe<double> currentCollectionStartTime;
+
+    while (e.Has()) {
+      if (e.Get().IsPause()) {
+        currentPauseStartTime = Some(e.Get().GetDouble());
+      } else if (e.Get().IsResume()) {
+        AddPausedRange(aWriter, "profiler-paused", currentPauseStartTime,
+                       Some(e.Get().GetDouble()));
+        currentPauseStartTime = Nothing();
+      } else if (e.Get().IsCollectionStart()) {
+        currentCollectionStartTime = Some(e.Get().GetDouble());
+      } else if (e.Get().IsCollectionEnd()) {
+        AddPausedRange(aWriter, "collecting", currentCollectionStartTime,
+                       Some(e.Get().GetDouble()));
+        currentCollectionStartTime = Nothing();
+      }
+      e.Next();
     }
-    e.Next();
-  }
 
-  if (currentPauseStartTime) {
-    AddPausedRange(aWriter, "profiler-paused", currentPauseStartTime,
-                   Nothing());
-  }
-  if (currentCollectionStartTime) {
-    AddPausedRange(aWriter, "collecting", currentCollectionStartTime,
-                   Nothing());
-  }
+    if (currentPauseStartTime) {
+      AddPausedRange(aWriter, "profiler-paused", currentPauseStartTime,
+                     Nothing());
+    }
+    if (currentCollectionStartTime) {
+      AddPausedRange(aWriter, "collecting", currentCollectionStartTime,
+                     Nothing());
+    }
+  });
 }
 
 bool ProfileBuffer::DuplicateLastSample(int aThreadId,
                                         const TimeStamp& aProcessStartTime,
                                         Maybe<uint64_t>& aLastSample) {
-  if (aLastSample && *aLastSample < mRangeStart) {
-    // The last sample is no longer within the buffer range, so we cannot use
-    // it. Reset the stored buffer position to Nothing().
-    aLastSample.reset();
-  }
-
   if (!aLastSample) {
     return false;
   }
 
-  uint64_t lastSampleStartPos = *aLastSample;
+  BlocksRingBuffer tempBuffer(BlocksRingBuffer::ThreadSafety::WithoutMutex,
+                              mWorkerBuffer.get(), WorkerBufferBytes);
 
-  MOZ_RELEASE_ASSERT(GetEntry(lastSampleStartPos).IsThreadId() &&
-                     GetEntry(lastSampleStartPos).GetInt() == aThreadId);
+  const bool ok = mEntries.Read([&](BlocksRingBuffer::Reader* aReader) {
+    MOZ_ASSERT(
+        aReader,
+        "BlocksRingBuffer cannot be out-of-session when sampler is running");
+
+    EntryGetter e(*aReader, *aLastSample);
+
+    if (e.CurPos() != *aLastSample) {
+      // The last sample is no longer within the buffer range, so we cannot
+      // use it. Reset the stored buffer position to Nothing().
+      aLastSample.reset();
+      return false;
+    }
+
+    MOZ_RELEASE_ASSERT(e.Has() && e.Get().IsThreadId() &&
+                       e.Get().GetInt() == aThreadId);
+
+    e.Next();
+
+    // Go through the whole entry and duplicate it, until we find the next
+    // one.
+    while (e.Has()) {
+      switch (e.Get().GetKind()) {
+        case ProfileBufferEntry::Kind::Pause:
+        case ProfileBufferEntry::Kind::Resume:
+        case ProfileBufferEntry::Kind::CollectionStart:
+        case ProfileBufferEntry::Kind::CollectionEnd:
+        case ProfileBufferEntry::Kind::ThreadId:
+          // We're done.
+          return true;
+        case ProfileBufferEntry::Kind::Time:
+          // Copy with new time
+          AddEntry(tempBuffer,
+                   ProfileBufferEntry::Time(
+                       (TimeStamp::NowUnfuzzed() - aProcessStartTime)
+                           .ToMilliseconds()));
+          break;
+        case ProfileBufferEntry::Kind::TimeBeforeCompactStack: {
+          // Copy with new time, followed by a compact stack.
+          AddEntry(tempBuffer,
+                   ProfileBufferEntry::TimeBeforeCompactStack(
+                       (TimeStamp::NowUnfuzzed() - aProcessStartTime)
+                           .ToMilliseconds()));
+
+          // The `CompactStack` *must* be present afterwards, but may not
+          // immediately follow `TimeBeforeCompactStack` (e.g., some markers
+          // could be written in-between), so we need to look for it in the
+          // following entries.
+          BlocksRingBuffer::BlockIterator it = e.Iterator();
+          for (;;) {
+            ++it;
+            if (it.IsAtEnd()) {
+              break;
+            }
+            BlocksRingBuffer::EntryReader er = *it;
+            auto kind = static_cast<ProfileBufferEntry::Kind>(
+                er.PeekObject<ProfileBufferEntry::KindUnderlyingType>());
+            MOZ_ASSERT(
+                static_cast<ProfileBufferEntry::KindUnderlyingType>(kind) <
+                static_cast<ProfileBufferEntry::KindUnderlyingType>(
+                    ProfileBufferEntry::Kind::MODERN_LIMIT));
+            if (kind == ProfileBufferEntry::Kind::CompactStack) {
+              // Found our CompactStack, just make a copy of the whole entry.
+              auto bytes = er.RemainingBytes();
+              MOZ_ASSERT(bytes < 65536);
+              tempBuffer.Put(bytes, [&](BlocksRingBuffer::EntryWriter* aEW) {
+                MOZ_ASSERT(aEW, "tempBuffer cannot be out-of-session");
+                er.ReadInto(*aEW, bytes);
+              });
+              break;
+            }
+            MOZ_ASSERT(kind >= ProfileBufferEntry::Kind::LEGACY_LIMIT,
+                       "There should be no legacy entries between "
+                       "TimeBeforeCompactStack and CompactStack");
+            // Here, we have encountered a non-legacy entry that was not the
+            // CompactStack we're looking for; just continue the search...
+          }
+          // We're done.
+          return true;
+        }
+        case ProfileBufferEntry::Kind::CounterKey:
+        case ProfileBufferEntry::Kind::Number:
+        case ProfileBufferEntry::Kind::Count:
+          // Don't copy anything not part of a thread's stack sample
+          break;
+        case ProfileBufferEntry::Kind::CounterId:
+          // CounterId is normally followed by Time - if so, we'd like
+          // to skip it.  If we duplicate Time, it won't hurt anything, just
+          // waste buffer space (and this can happen if the CounterId has
+          // fallen off the end of the buffer, but Time (and Number/Count)
+          // are still in the buffer).
+          e.Next();
+          if (e.Has() && e.Get().GetKind() != ProfileBufferEntry::Kind::Time) {
+            // this would only happen if there was an invalid sequence
+            // in the buffer.  Don't skip it.
+            continue;
+          }
+          // we've skipped Time
+          break;
+        case ProfileBufferEntry::Kind::ProfilerOverheadTime:
+          // ProfilerOverheadTime is normally followed by
+          // ProfilerOverheadDuration*4 - if so, we'd like to skip it. Don't
+          // duplicate, as we are in the middle of a sampling and will soon
+          // capture its own overhead.
+          e.Next();
+          // A missing Time would only happen if there was an invalid
+          // sequence in the buffer. Don't skip unexpected entry.
+          if (e.Has() &&
+              e.Get().GetKind() !=
+                  ProfileBufferEntry::Kind::ProfilerOverheadDuration) {
+            continue;
+          }
+          e.Next();
+          if (e.Has() &&
+              e.Get().GetKind() !=
+                  ProfileBufferEntry::Kind::ProfilerOverheadDuration) {
+            continue;
+          }
+          e.Next();
+          if (e.Has() &&
+              e.Get().GetKind() !=
+                  ProfileBufferEntry::Kind::ProfilerOverheadDuration) {
+            continue;
+          }
+          e.Next();
+          if (e.Has() &&
+              e.Get().GetKind() !=
+                  ProfileBufferEntry::Kind::ProfilerOverheadDuration) {
+            continue;
+          }
+          // we've skipped ProfilerOverheadTime and
+          // ProfilerOverheadDuration*4.
+          break;
+        default: {
+          // Copy anything else we don't know about.
+          AddEntry(tempBuffer, e.Get());
+          break;
+        }
+      }
+      e.Next();
+    }
+    return true;
+  });
+
+  if (!ok) {
+    return false;
+  }
+
+  // If the buffer was big enough, there won't be any cleared blocks.
+  if (tempBuffer.GetState().mClearedBlockCount != 0) {
+    // No need to try to read stack again as it won't fit. Reset the stored
+    // buffer position to Nothing().
+    aLastSample.reset();
+    return false;
+  }
 
   aLastSample = Some(AddThreadIdEntry(aThreadId));
 
-  EntryGetter e(*this, lastSampleStartPos + 1);
+  mEntries.AppendContents(tempBuffer);
 
-  // Go through the whole entry and duplicate it, until we find the next one.
-  while (e.Has()) {
-    switch (e.Get().GetKind()) {
-      case ProfileBufferEntry::Kind::Pause:
-      case ProfileBufferEntry::Kind::Resume:
-      case ProfileBufferEntry::Kind::CollectionStart:
-      case ProfileBufferEntry::Kind::CollectionEnd:
-      case ProfileBufferEntry::Kind::ThreadId:
-        // We're done.
-        return true;
-      case ProfileBufferEntry::Kind::Time:
-        // Copy with new time
-        AddEntry(ProfileBufferEntry::Time(
-            (TimeStamp::Now() - aProcessStartTime).ToMilliseconds()));
-        break;
-      case ProfileBufferEntry::Kind::Marker:
-      case ProfileBufferEntry::Kind::ResidentMemory:
-      case ProfileBufferEntry::Kind::UnsharedMemory:
-      case ProfileBufferEntry::Kind::CounterKey:
-      case ProfileBufferEntry::Kind::Number:
-      case ProfileBufferEntry::Kind::Count:
-      case ProfileBufferEntry::Kind::Responsiveness:
-        // Don't copy anything not part of a thread's stack sample
-        break;
-      case ProfileBufferEntry::Kind::CounterId:
-        // CounterId is normally followed by Time - if so, we'd like
-        // to skip it.  If we duplicate Time, it won't hurt anything, just
-        // waste buffer space (and this can happen if the CounterId has
-        // fallen off the end of the buffer, but Time (and Number/Count)
-        // are still in the buffer).
-        e.Next();
-        if (e.Has() && e.Get().GetKind() != ProfileBufferEntry::Kind::Time) {
-          // this would only happen if there was an invalid sequence
-          // in the buffer.  Don't skip it.
-          continue;
-        }
-        // we've skipped Time
-        break;
-      case ProfileBufferEntry::Kind::ProfilerOverheadTime:
-        // ProfilerOverheadTime is normally followed by
-        // ProfilerOverheadDuration*4 - if so, we'd like to skip it. Don't
-        // duplicate, as we are in the middle of a sampling and will soon
-        // capture its own overhead.
-        e.Next();
-        // A missing Time would only happen if there was an invalid sequence
-        // in the buffer. Don't skip unexpected entry.
-        if (e.Has() && e.Get().GetKind() !=
-                           ProfileBufferEntry::Kind::ProfilerOverheadDuration) {
-          continue;
-        }
-        e.Next();
-        if (e.Has() && e.Get().GetKind() !=
-                           ProfileBufferEntry::Kind::ProfilerOverheadDuration) {
-          continue;
-        }
-        e.Next();
-        if (e.Has() && e.Get().GetKind() !=
-                           ProfileBufferEntry::Kind::ProfilerOverheadDuration) {
-          continue;
-        }
-        e.Next();
-        if (e.Has() && e.Get().GetKind() !=
-                           ProfileBufferEntry::Kind::ProfilerOverheadDuration) {
-          continue;
-        }
-        // we've skipped ProfilerOverheadTime and ProfilerOverheadDuration*4.
-        break;
-      default: {
-        // Copy anything else we don't know about.
-        ProfileBufferEntry entry = e.Get();
-        AddEntry(entry);
-        break;
-      }
-    }
-    e.Next();
-  }
   return true;
 }
 
 void ProfileBuffer::DiscardSamplesBeforeTime(double aTime) {
-  EntryGetter e(*this);
-  for (;;) {
-    // This block skips entries until we find the start of the next sample.
-    // This is useful in three situations.
-    //
-    // - The circular buffer overwrites old entries, so when we start parsing
-    //   we might be in the middle of a sample, and we must skip forward to the
-    //   start of the next sample.
-    //
-    // - We skip samples that don't have an appropriate ThreadId or Time.
-    //
-    // - We skip range Pause, Resume, CollectionStart, Marker, and CollectionEnd
-    //   entries between samples.
-    while (e.Has()) {
-      if (e.Get().IsThreadId()) {
-        break;
-      } else {
+  const BlockIndex firstBlockToKeep = mEntries.Read([&](BlocksRingBuffer::
+                                                            Reader* aReader) {
+    MOZ_ASSERT(
+        aReader,
+        "BlocksRingBuffer cannot be out-of-session when sampler is running");
+
+    EntryGetter e(*aReader);
+
+    const BlockIndex bufferStartPos = e.CurBlockIndex();
+    for (;;) {
+      // This block skips entries until we find the start of the next
+      // sample. This is useful in three situations.
+      //
+      // - The circular buffer overwrites old entries, so when we start
+      //   parsing we might be in the middle of a sample, and we must skip
+      //   forward to the start of the next sample.
+      //
+      // - We skip samples that don't have an appropriate ThreadId or Time.
+      //
+      // - We skip range Pause, Resume, CollectionStart, Marker, and
+      //   CollectionEnd entries between samples.
+      while (e.Has()) {
+        if (e.Get().IsThreadId()) {
+          break;
+        }
         e.Next();
       }
-    }
 
-    if (!e.Has()) {
-      break;
-    }
+      if (!e.Has()) {
+        return bufferStartPos;
+      }
 
-    MOZ_RELEASE_ASSERT(e.Get().IsThreadId());
-    uint64_t sampleStartPos = e.CurPos();
-    e.Next();
+      MOZ_RELEASE_ASSERT(e.Get().IsThreadId());
+      const BlockIndex sampleStartPos = e.CurBlockIndex();
+      e.Next();
 
-    if (e.Has() && e.Get().IsTime()) {
-      double sampleTime = e.Get().GetDouble();
+      if (e.Has() && (e.Get().IsTime() || e.Get().IsTimeBeforeCompactStack())) {
+        double sampleTime = e.Get().GetDouble();
 
-      if (sampleTime >= aTime) {
-        // This is the first sample within the window of time that we want to
-        // keep. Throw away all samples before sampleStartPos and return.
-        mRangeStart = sampleStartPos;
-        return;
+        if (sampleTime >= aTime) {
+          // This is the first sample within the window of time that we want
+          // to keep. Throw away all samples before sampleStartPos and
+          // return.
+          return sampleStartPos;
+        }
       }
     }
-  }
+  });
+  mEntries.ClearBefore(firstBlockToKeep);
 }
 
 // END ProfileBuffer
diff --git a/tools/profiler/core/ProfileBufferEntry.h b/tools/profiler/core/ProfileBufferEntry.h
index 884f7431ea..8a39bf8285 100644
--- a/tools/profiler/core/ProfileBufferEntry.h
+++ b/tools/profiler/core/ProfileBufferEntry.h
@@ -18,44 +18,73 @@
 #include "mozilla/Vector.h"
 #include "nsString.h"
 
-class ProfilerMarker;
+class ProfilerCodeAddressService;
 
 // NOTE!  If you add entries, you need to verify if they need to be added to the
 // switch statement in DuplicateLastSample!
-#define FOR_EACH_PROFILE_BUFFER_ENTRY_KIND(MACRO)                   \
-  MACRO(CategoryPair, int)                                          \
-  MACRO(CollectionStart, double)                                    \
-  MACRO(CollectionEnd, double)                                      \
-  MACRO(Label, const char*)                                         \
-  MACRO(FrameFlags, uint64_t)                                       \
-  MACRO(DynamicStringFragment, char*) /* char[kNumChars], really */ \
-  MACRO(JitReturnAddr, void*)                                       \
-  MACRO(LineNumber, int)                                            \
-  MACRO(ColumnNumber, int)                                          \
-  MACRO(NativeLeafAddr, void*)                                      \
-  MACRO(Marker, ProfilerMarker*)                                    \
-  MACRO(Pause, double)                                              \
-  MACRO(Responsiveness, double)                                     \
-  MACRO(Resume, double)                                             \
-  MACRO(ThreadId, int)                                              \
-  MACRO(Time, double)                                               \
-  MACRO(ResidentMemory, uint64_t)                                   \
-  MACRO(UnsharedMemory, uint64_t)                                   \
-  MACRO(CounterId, void*)                                           \
-  MACRO(CounterKey, uint64_t)                                       \
-  MACRO(Number, uint64_t)                                           \
-  MACRO(Count, int64_t)                                             \
-  MACRO(ProfilerOverheadTime, double)                               \
-  MACRO(ProfilerOverheadDuration, double)
+// This will evaluate the MACRO with (KIND, TYPE, SIZE)
+#define FOR_EACH_PROFILE_BUFFER_ENTRY_KIND(MACRO)                    \
+  MACRO(CategoryPair, int, sizeof(int))                              \
+  MACRO(CollectionStart, double, sizeof(double))                     \
+  MACRO(CollectionEnd, double, sizeof(double))                       \
+  MACRO(Label, const char*, sizeof(const char*))                     \
+  MACRO(FrameFlags, uint64_t, sizeof(uint64_t))                      \
+  MACRO(DynamicStringFragment, char*, ProfileBufferEntry::kNumChars) \
+  MACRO(JitReturnAddr, void*, sizeof(void*))                         \
+  MACRO(LineNumber, int, sizeof(int))                                \
+  MACRO(ColumnNumber, int, sizeof(int))                              \
+  MACRO(NativeLeafAddr, void*, sizeof(void*))                        \
+  MACRO(Pause, double, sizeof(double))                               \
+  MACRO(Resume, double, sizeof(double))                              \
+  MACRO(ThreadId, int, sizeof(int))                                  \
+  MACRO(Time, double, sizeof(double))                                \
+  MACRO(TimeBeforeCompactStack, double, sizeof(double))              \
+  MACRO(CounterId, void*, sizeof(void*))                             \
+  MACRO(CounterKey, uint64_t, sizeof(uint64_t))                      \
+  MACRO(Number, uint64_t, sizeof(uint64_t))                          \
+  MACRO(Count, int64_t, sizeof(int64_t))                             \
+  MACRO(ProfilerOverheadTime, double, sizeof(double))                \
+  MACRO(ProfilerOverheadDuration, double, sizeof(double))
 
 class ProfileBufferEntry {
  public:
-  enum class Kind : uint8_t {
+  // The `Kind` is a single byte identifying the type of data that is actually
+  // stored in a `ProfileBufferEntry`, as per the list in
+  // `FOR_EACH_PROFILE_BUFFER_ENTRY_KIND`.
+  //
+  // This byte is also used to identify entries in BlocksRingBuffer blocks, for
+  // both "legacy" entries that do contain a `ProfileBufferEntry`, and for new
+  // types of entries that may carry more data of different types.
+  // TODO: Eventually each type of "legacy" entry should be replaced with newer,
+  // more efficient kinds of entries (e.g., stack frames could be stored in one
+  // bigger entry, instead of multiple `ProfileBufferEntry`s); then we could
+  // discard `ProfileBufferEntry` and move this enum to a more appropriate spot.
+  using KindUnderlyingType = uint8_t;
+  enum class Kind : KindUnderlyingType {
     INVALID = 0,
-#define KIND(k, t) k,
+#define KIND(KIND, TYPE, SIZE) KIND,
     FOR_EACH_PROFILE_BUFFER_ENTRY_KIND(KIND)
 #undef KIND
-        LIMIT
+
+    // Any value under `LEGACY_LIMIT` represents a `ProfileBufferEntry`.
+    LEGACY_LIMIT,
+
+    // Any value starting here does *not* represent a `ProfileBufferEntry` and
+    // requires separate decoding and handling.
+
+    // Marker data, including payload.
+    MarkerData = LEGACY_LIMIT,
+
+    // Optional between TimeBeforeCompactStack and CompactStack.
+    UnresponsiveDurationMs,
+
+    // Collection of legacy stack entries, must follow a ThreadId and
+    // TimeBeforeCompactStack (which are not included in the CompactStack;
+    // TimeBeforeCompactStack is equivalent to Time, but indicates that a
+    // CompactStack follows shortly afterwards).
+    CompactStack,
+
+    MODERN_LIMIT
   };
 
   ProfileBufferEntry();
@@ -69,24 +98,23 @@ class ProfileBufferEntry {
   ProfileBufferEntry(Kind aKind, const char* aString);
   ProfileBufferEntry(Kind aKind, char aChars[kNumChars]);
   ProfileBufferEntry(Kind aKind, void* aPtr);
-  ProfileBufferEntry(Kind aKind, ProfilerMarker* aMarker);
   ProfileBufferEntry(Kind aKind, double aDouble);
   ProfileBufferEntry(Kind aKind, int64_t aInt64);
   ProfileBufferEntry(Kind aKind, uint64_t aUint64);
   ProfileBufferEntry(Kind aKind, int aInt);
 
  public:
-#define CTOR(k, t)                            \
-  static ProfileBufferEntry k(t aVal) {       \
-    return ProfileBufferEntry(Kind::k, aVal); \
+#define CTOR(KIND, TYPE, SIZE)                   \
+  static ProfileBufferEntry KIND(TYPE aVal) {    \
+    return ProfileBufferEntry(Kind::KIND, aVal); \
   }
   FOR_EACH_PROFILE_BUFFER_ENTRY_KIND(CTOR)
 #undef CTOR
 
   Kind GetKind() const { return mKind; }
 
-#define IS_KIND(k, t) \
-  bool Is##k() const { return mKind == Kind::k; }
+#define IS_KIND(KIND, TYPE, SIZE) \
+  bool Is##KIND() const { return mKind == Kind::KIND; }
   FOR_EACH_PROFILE_BUFFER_ENTRY_KIND(IS_KIND)
 #undef IS_KIND
 
@@ -103,7 +131,6 @@ class ProfileBufferEntry {
 
   const char* GetString() const;
   void* GetPtr() const;
-  ProfilerMarker* GetMarker() const;
   double GetDouble() const;
   int GetInt() const;
   int64_t GetInt64() const;
@@ -389,6 +416,8 @@ class UniqueStacks {
  public:
   mozilla::UniquePtr<UniqueJSONStrings> mUniqueStrings;
 
+  ProfilerCodeAddressService* mCodeAddressService = nullptr;
+
  private:
   SpliceableChunkedJSONWriter mFrameTableWriter;
   mozilla::HashMap<FrameKey, uint32_t, FrameKeyHasher> mFrameToIndexMap;
@@ -466,11 +495,14 @@ class UniqueStacks {
 //     "schema":
 //     {
 //       "location": 0,       /* index into stringTable */
-//       "implementation": 1, /* index into stringTable */
-//       "optimizations": 2,  /* arbitrary JSON */
-//       "line": 3,           /* number */
-//       "column": 4,         /* number */
-//       "category": 5        /* number */
+//       "relevantForJS": 1,  /* bool */
+//       "implementation": 2, /* index into stringTable */
+//       "optimizations": 3,  /* arbitrary JSON */
+//       "line": 4,           /* number */
+//       "column": 5,         /* number */
+//       "category": 6        /* index into profile.meta.categories */
+//       "subcategory": 7     /* index into
+//       profile.meta.categories[category].subcategories */
 //     },
 //     "data":
 //     [
@@ -527,24 +559,6 @@ class UniqueStacks {
 //     },
 //     /* more counters */
 //   ],
-//   "memory":
-//   {
-//     "initial_heap": 12345678,
-//     "samples:
-//     {
-//       "schema":
-//       {
-//         "time": 1,            /* number */
-//         "rss": 2,             /* number */
-//         "uss": 3              /* number */
-//       },
-//       "data":
-//       [
-//         /* { time: 0.1, rss: 12345678, uss: 87654321} */
-//         [ 0.1, 12345678, 87654321 ]
-//       ]
-//     },
-//   },
 // }
 //
 #endif /* ndef ProfileBufferEntry_h */
diff --git a/tools/profiler/core/ProfiledThreadData.cpp b/tools/profiler/core/ProfiledThreadData.cpp
index 9d0b210580..98414a212d 100644
--- a/tools/profiler/core/ProfiledThreadData.cpp
+++ b/tools/profiler/core/ProfiledThreadData.cpp
@@ -15,13 +15,9 @@
 #endif
 
 ProfiledThreadData::ProfiledThreadData(ThreadInfo* aThreadInfo,
-                                       nsIEventTarget* aEventTarget,
-                                       bool aIncludeResponsiveness)
+                                       nsIEventTarget* aEventTarget)
     : mThreadInfo(aThreadInfo) {
   MOZ_COUNT_CTOR(ProfiledThreadData);
-  if (aIncludeResponsiveness) {
-    mResponsiveness.emplace(aEventTarget, aThreadInfo->IsMainThread());
-  }
 }
 
 ProfiledThreadData::~ProfiledThreadData() {
@@ -33,9 +29,11 @@ void ProfiledThreadData::StreamJSON(const ProfileBuffer& aBuffer,
                                     SpliceableJSONWriter& aWriter,
                                     const nsACString& aProcessName,
                                     const mozilla::TimeStamp& aProcessStartTime,
-                                    double aSinceTime, bool JSTracerEnabled) {
+                                    double aSinceTime, bool JSTracerEnabled,
+                                    ProfilerCodeAddressService* aService) {
   if (mJITFrameInfoForPreviousJSContexts &&
-      mJITFrameInfoForPreviousJSContexts->HasExpired(aBuffer.mRangeStart)) {
+      mJITFrameInfoForPreviousJSContexts->HasExpired(
+          aBuffer.BufferRangeStart())) {
     mJITFrameInfoForPreviousJSContexts = nullptr;
   }
 
@@ -52,6 +50,7 @@ void ProfiledThreadData::StreamJSON(const ProfileBuffer& aBuffer,
   }
 
   UniqueStacks uniqueStacks(std::move(jitFrameInfo));
+  uniqueStacks.mCodeAddressService = aService;
 
   aWriter.Start();
   {
@@ -85,6 +84,7 @@ void ProfiledThreadData::StreamJSON(const ProfileBuffer& aBuffer,
         schema.WriteField("line");
         schema.WriteField("column");
         schema.WriteField("category");
+        schema.WriteField("subcategory");
       }
 
       aWriter.StartArrayProperty("data");
@@ -241,8 +241,6 @@ void StreamSamplesAndMarkers(const char* aName, int aThreadId,
       schema.WriteField("stack");
       schema.WriteField("time");
       schema.WriteField("responsiveness");
-      schema.WriteField("rss");
-      schema.WriteField("uss");
     }
 
     aWriter.StartArrayProperty("data");
@@ -284,7 +282,8 @@ void ProfiledThreadData::NotifyAboutToLoseJSContext(
   MOZ_RELEASE_ASSERT(aContext);
 
   if (mJITFrameInfoForPreviousJSContexts &&
-      mJITFrameInfoForPreviousJSContexts->HasExpired(aBuffer.mRangeStart)) {
+      mJITFrameInfoForPreviousJSContexts->HasExpired(
+          aBuffer.BufferRangeStart())) {
     mJITFrameInfoForPreviousJSContexts = nullptr;
   }
 
diff --git a/tools/profiler/core/ProfiledThreadData.h b/tools/profiler/core/ProfiledThreadData.h
index 11f8d82f8f..0e76d8c71d 100644
--- a/tools/profiler/core/ProfiledThreadData.h
+++ b/tools/profiler/core/ProfiledThreadData.h
@@ -8,7 +8,6 @@
 #include "platform.h"
 #include "ProfileBufferEntry.h"
 #include "ThreadInfo.h"
-#include "ThreadResponsiveness.h"
 
 #include "js/ProfilingStack.h"
 #include "mozilla/TimeStamp.h"
@@ -41,17 +40,15 @@ class ProfileBuffer;
 // when the profiler is stopped.
 class ProfiledThreadData final {
  public:
-  ProfiledThreadData(ThreadInfo* aThreadInfo, nsIEventTarget* aEventTarget,
-                     bool aIncludeResponsiveness);
+  ProfiledThreadData(ThreadInfo* aThreadInfo, nsIEventTarget* aEventTarget);
   ~ProfiledThreadData();
 
   void NotifyUnregistered(uint64_t aBufferPosition) {
-    mResponsiveness.reset();
     mLastSample = mozilla::Nothing();
     MOZ_ASSERT(!mBufferPositionWhenReceivedJSContext,
                "JSContext should have been cleared before the thread was "
                "unregistered");
-    mUnregisterTime = mozilla::TimeStamp::Now();
+    mUnregisterTime = mozilla::TimeStamp::NowUnfuzzed();
     mBufferPositionWhenUnregistered = mozilla::Some(aBufferPosition);
   }
   mozilla::Maybe<uint64_t> BufferPositionWhenUnregistered() {
@@ -63,18 +60,12 @@ class ProfiledThreadData final {
   void StreamJSON(const ProfileBuffer& aBuffer, JSContext* aCx,
                   SpliceableJSONWriter& aWriter, const nsACString& aProcessName,
                   const mozilla::TimeStamp& aProcessStartTime,
-                  double aSinceTime, bool aJSTracerEnabled);
+                  double aSinceTime, bool aJSTracerEnabled,
+                  ProfilerCodeAddressService* aService);
 
   void StreamTraceLoggerJSON(JSContext* aCx, SpliceableJSONWriter& aWriter,
                              const mozilla::TimeStamp& aProcessStartTime);
 
-  // Returns nullptr if this is not the main thread, the responsiveness
-  // feature is not turned on, or if this thread is not being profiled.
-  ThreadResponsiveness* GetThreadResponsiveness() {
-    ThreadResponsiveness* responsiveness = mResponsiveness.ptrOr(nullptr);
-    return responsiveness;
-  }
-
   const RefPtr<ThreadInfo> Info() const { return mThreadInfo; }
 
   void NotifyReceivedJSContext(uint64_t aCurrentBufferPosition) {
@@ -106,10 +97,6 @@ class ProfiledThreadData final {
   // The following fields are only used while this thread is alive and
   // registered. They become Nothing() once the thread is unregistered.
 
-  // A helper object that instruments nsIThreads to obtain responsiveness
-  // information about their event loop.
-  mozilla::Maybe<ThreadResponsiveness> mResponsiveness;
-
   // When sampling, this holds the position in ActivePS::mBuffer of the most
   // recent sample for this thread, or Nothing() if there is no sample for this
   // thread in the buffer.
diff --git a/tools/profiler/core/ProfilerBacktrace.cpp b/tools/profiler/core/ProfilerBacktrace.cpp
index 4d78ba5703..f8d15a5c10 100644
--- a/tools/profiler/core/ProfilerBacktrace.cpp
+++ b/tools/profiler/core/ProfilerBacktrace.cpp
@@ -9,10 +9,23 @@
 #include "ProfileJSONWriter.h"
 #include "ThreadInfo.h"
 
-ProfilerBacktrace::ProfilerBacktrace(const char* aName, int aThreadId,
-                                     mozilla::UniquePtr<ProfileBuffer> aBuffer)
-    : mName(strdup(aName)), mThreadId(aThreadId), mBuffer(std::move(aBuffer)) {
+ProfilerBacktrace::ProfilerBacktrace(
+    const char* aName, int aThreadId,
+    UniquePtr<mozilla::BlocksRingBuffer> aBlocksRingBuffer,
+    mozilla::UniquePtr<ProfileBuffer> aProfileBuffer)
+    : mName(strdup(aName)),
+      mThreadId(aThreadId),
+      mBlocksRingBuffer(std::move(aBlocksRingBuffer)),
+      mProfileBuffer(std::move(aProfileBuffer)) {
   MOZ_COUNT_CTOR(ProfilerBacktrace);
+  MOZ_ASSERT(
+      !!mBlocksRingBuffer,
+      "ProfilerBacktrace only takes a non-null UniquePtr<BlocksRingBuffer>");
+  MOZ_ASSERT(
+      !!mProfileBuffer,
+      "ProfilerBacktrace only takes a non-null UniquePtr<ProfileBuffer>");
+  MOZ_ASSERT(!mBlocksRingBuffer->IsThreadSafe(),
+             "ProfilerBacktrace only takes a non-thread-safe BlocksRingBuffer");
 }
 
 ProfilerBacktrace::~ProfilerBacktrace() { MOZ_COUNT_DTOR(ProfilerBacktrace); }
@@ -21,10 +34,10 @@ void ProfilerBacktrace::StreamJSON(SpliceableJSONWriter& aWriter,
                                    const mozilla::TimeStamp& aProcessStartTime,
                                    UniqueStacks& aUniqueStacks) {
   // Unlike ProfiledThreadData::StreamJSON, we don't need to call
-  // ProfileBuffer::AddJITInfoForRange because mBuffer does not contain any
-  // JitReturnAddr entries. For synchronous samples, JIT frames get expanded
+  // ProfileBuffer::AddJITInfoForRange because mProfileBuffer does not contain
+  // any JitReturnAddr entries. For synchronous samples, JIT frames get expanded
   // at sample time.
-  StreamSamplesAndMarkers(mName.get(), mThreadId, *mBuffer.get(), aWriter,
+  StreamSamplesAndMarkers(mName.get(), mThreadId, *mProfileBuffer, aWriter,
                           NS_LITERAL_CSTRING(""), aProcessStartTime,
                           /* aRegisterTime */ mozilla::TimeStamp(),
                           /* aUnregisterTime */ mozilla::TimeStamp(),
diff --git a/tools/profiler/core/ProfilerBacktrace.h b/tools/profiler/core/ProfilerBacktrace.h
index aad2c88d9b..a802aa9842 100644
--- a/tools/profiler/core/ProfilerBacktrace.h
+++ b/tools/profiler/core/ProfilerBacktrace.h
@@ -5,22 +5,27 @@
 #ifndef __PROFILER_BACKTRACE_H
 #define __PROFILER_BACKTRACE_H
 
+#include "ProfileBuffer.h"
+
 #include "mozilla/UniquePtrExtensions.h"
 
 class ProfileBuffer;
+class ProfilerCodeAddressService;
 class SpliceableJSONWriter;
 class ThreadInfo;
 class UniqueStacks;
 
 namespace mozilla {
+class BlocksRingBuffer;
 class TimeStamp;
-}
+}  // namespace mozilla
 
 // ProfilerBacktrace encapsulates a synchronous sample.
 class ProfilerBacktrace {
  public:
   ProfilerBacktrace(const char* aName, int aThreadId,
-                    mozilla::UniquePtr<ProfileBuffer> aBuffer);
+                    UniquePtr<mozilla::BlocksRingBuffer> aBlocksRingBuffer,
+                    mozilla::UniquePtr<ProfileBuffer> aProfileBuffer);
   ~ProfilerBacktrace();
 
   // ProfilerBacktraces' stacks are deduplicated in the context of the
@@ -34,12 +39,91 @@ class ProfilerBacktrace {
                   UniqueStacks& aUniqueStacks);
 
  private:
-  ProfilerBacktrace(const ProfilerBacktrace&);
-  ProfilerBacktrace& operator=(const ProfilerBacktrace&);
+  // Used to serialize a ProfilerBacktrace.
+  friend struct BlocksRingBuffer::Serializer<ProfilerBacktrace>;
+  friend struct BlocksRingBuffer::Deserializer<ProfilerBacktrace>;
 
   mozilla::UniqueFreePtr<char> mName;
   int mThreadId;
-  mozilla::UniquePtr<ProfileBuffer> mBuffer;
+  // `BlocksRingBuffer` in which `mProfileBuffer` stores its data; must be
+  // located before `mProfileBuffer` so that it's destroyed after.
+  UniquePtr<mozilla::BlocksRingBuffer> mBlocksRingBuffer;
+  mozilla::UniquePtr<ProfileBuffer> mProfileBuffer;
 };
 
+namespace mozilla {
+
+// Format: [ UniquePtr<BlockRingsBuffer> | threadId | name ]
+// Initial len==0 marks a nullptr or empty backtrace.
+template <>
+struct BlocksRingBuffer::Serializer<ProfilerBacktrace> {
+  static Length Bytes(const ProfilerBacktrace& aBacktrace) {
+    if (!aBacktrace.mProfileBuffer) {
+      return ULEB128Size<Length>(0);
+    }
+    auto bufferBytes = SumBytes(*aBacktrace.mBlocksRingBuffer);
+    if (bufferBytes == 0) {
+      return ULEB128Size<Length>(0);
+    }
+    return bufferBytes +
+           SumBytes(aBacktrace.mThreadId,
+                    WrapBlocksRingBufferUnownedCString(aBacktrace.mName.get()));
+  }
+  static void Write(EntryWriter& aEW, const ProfilerBacktrace& aBacktrace) {
+    if (!aBacktrace.mProfileBuffer ||
+        SumBytes(*aBacktrace.mBlocksRingBuffer) == 0) {
+      aEW.WriteULEB128(0u);
+      return;
+    }
+    aEW.WriteObject(*aBacktrace.mBlocksRingBuffer);
+    aEW.WriteObject(aBacktrace.mThreadId);
+    aEW.WriteObject(WrapBlocksRingBufferUnownedCString(aBacktrace.mName.get()));
+  }
+};
+
+template <typename Destructor>
+struct BlocksRingBuffer::Serializer<UniquePtr<ProfilerBacktrace, Destructor>> {
+  static Length Bytes(
+      const UniquePtr<ProfilerBacktrace, Destructor>& aBacktrace) {
+    if (!aBacktrace) {
+      return ULEB128Size<Length>(0);
+    }
+    return SumBytes(*aBacktrace);
+  }
+  static void Write(
+      EntryWriter& aEW,
+      const UniquePtr<ProfilerBacktrace, Destructor>& aBacktrace) {
+    if (!aBacktrace) {
+      aEW.WriteULEB128(0u);
+      return;
+    }
+    aEW.WriteObject(*aBacktrace);
+  }
+};
+template <typename Destructor>
+struct BlocksRingBuffer::Deserializer<
+    UniquePtr<ProfilerBacktrace, Destructor>> {
+  static void ReadInto(EntryReader& aER,
+                       UniquePtr<ProfilerBacktrace, Destructor>& aBacktrace) {
+    aBacktrace = Read(aER);
+  }
+  static UniquePtr<ProfilerBacktrace, Destructor> Read(EntryReader& aER) {
+    auto blocksRingBuffer = aER.ReadObject<UniquePtr<BlocksRingBuffer>>();
+    if (!blocksRingBuffer) {
+      return nullptr;
+    }
+    MOZ_ASSERT(
+        !blocksRingBuffer->IsThreadSafe(),
+        "ProfilerBacktrace only stores non-thread-safe BlocksRingBuffers");
+    int threadId = aER.ReadObject<int>();
+    std::string name = aER.ReadObject<std::string>();
+    auto profileBuffer = MakeUnique<ProfileBuffer>(*blocksRingBuffer);
+    return UniquePtr<ProfilerBacktrace, Destructor>{new ProfilerBacktrace(
+        name.c_str(), threadId, std::move(blocksRingBuffer),
+        std::move(profileBuffer))};
+  }
+};
+
+}  // namespace mozilla
+
 #endif  // __PROFILER_BACKTRACE_H
diff --git a/tools/profiler/core/ProfilerCodeAddressService.cpp b/tools/profiler/core/ProfilerCodeAddressService.cpp
new file mode 100644
index 0000000000..f167bd13fb
--- /dev/null
+++ b/tools/profiler/core/ProfilerCodeAddressService.cpp
@@ -0,0 +1,73 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "ProfilerCodeAddressService.h"
+
+#include "platform.h"
+#include "mozilla/StackWalk.h"
+
+using namespace mozilla;
+
+#ifdef XP_LINUX
+static char* SearchSymbolTable(SymbolTable& aTable, uint32_t aOffset) {
+  size_t index;
+  bool exact =
+      BinarySearch(aTable.mAddrs, 0, aTable.mAddrs.Length(), aOffset, &index);
+
+  if (index == 0 && !exact) {
+    // Our offset is before the first symbol in the table; no result.
+    return nullptr;
+  }
+
+  // Extract the (mangled) symbol name out of the string table.
+  auto strings = reinterpret_cast<char*>(aTable.mBuffer.Elements());
+  nsCString symbol;
+  symbol.Append(strings + aTable.mIndex[index - 1],
+                aTable.mIndex[index] - aTable.mIndex[index - 1]);
+
+  // First try demangling as a Rust identifier.
+  char demangled[1024];
+  if (!profiler_demangle_rust(symbol.get(), demangled,
+                              ArrayLength(demangled))) {
+    // Then as a C++ identifier.
+    DemangleSymbol(symbol.get(), demangled, ArrayLength(demangled));
+  }
+  demangled[ArrayLength(demangled) - 1] = '\0';
+
+  // Use the mangled name if we didn't successfully demangle.
+  return strdup(demangled[0] != '\0' ? demangled : symbol.get());
+}
+#endif
+
+bool ProfilerCodeAddressService::GetFunction(const void* aPc,
+                                             nsACString& aResult) {
+  Entry& entry = GetEntry(aPc);
+
+#ifdef XP_LINUX
+  // On Linux, most symbols will not be found by the MozDescribeCodeAddress call
+  // that GetEntry does.  So we read the symbol table directly from the ELF
+  // image.
+
+  // SymbolTable currently assumes library offsets will not be larger than
+  // 4 GiB.
+  if (entry.mLOffset <= 0xFFFFFFFF && !entry.mFunction) {
+    auto p = mSymbolTables.lookupForAdd(entry.mLibrary);
+    if (!p) {
+      if (!mSymbolTables.add(p, entry.mLibrary, SymbolTable())) {
+        MOZ_CRASH("ProfilerCodeAddressService OOM");
+      }
+      profiler_get_symbol_table(entry.mLibrary, nullptr, &p->value());
+    }
+    entry.mFunction =
+        SearchSymbolTable(p->value(), static_cast<uint32_t>(entry.mLOffset));
+  }
+#endif
+
+  if (!entry.mFunction || entry.mFunction[0] == '\0') {
+    return false;
+  }
+
+  aResult = nsDependentCString(entry.mFunction);
+  return true;
+}
diff --git a/tools/profiler/core/ProfilerMarker.h b/tools/profiler/core/ProfilerMarker.h
deleted file mode 100644
index 3d377cf3a7..0000000000
--- a/tools/profiler/core/ProfilerMarker.h
+++ /dev/null
@@ -1,168 +0,0 @@
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-#ifndef ProfilerMarker_h
-#define ProfilerMarker_h
-
-#include "ProfileBufferEntry.h"
-#include "ProfileJSONWriter.h"
-#include "ProfilerMarkerPayload.h"
-
-#include "mozilla/UniquePtrExtensions.h"
-
-template <typename T>
-class ProfilerLinkedList;
-
-class ProfilerMarker {
-  friend class ProfilerLinkedList<ProfilerMarker>;
-
- public:
-  explicit ProfilerMarker(
-      const char* aMarkerName, JS::ProfilingCategoryPair aCategoryPair,
-      int aThreadId,
-      mozilla::UniquePtr<ProfilerMarkerPayload> aPayload = nullptr,
-      double aTime = 0)
-      : mMarkerName(strdup(aMarkerName)),
-        mPayload(std::move(aPayload)),
-        mNext{nullptr},
-        mTime(aTime),
-        mPositionInBuffer{0},
-        mThreadId{aThreadId},
-        mCategoryPair{aCategoryPair} {}
-
-  void SetPositionInBuffer(uint64_t aPosition) {
-    mPositionInBuffer = aPosition;
-  }
-
-  bool HasExpired(uint64_t aBufferRangeStart) const {
-    return mPositionInBuffer < aBufferRangeStart;
-  }
-
-  double GetTime() const { return mTime; }
-
-  int GetThreadId() const { return mThreadId; }
-
-  void StreamJSON(SpliceableJSONWriter& aWriter,
-                  const mozilla::TimeStamp& aProcessStartTime,
-                  UniqueStacks& aUniqueStacks) const {
-    // Schema:
-    //   [name, time, category, data]
-
-    aWriter.StartArrayElement();
-    {
-      aUniqueStacks.mUniqueStrings->WriteElement(aWriter, mMarkerName.get());
-      aWriter.DoubleElement(mTime);
-      const JS::ProfilingCategoryPairInfo& info =
-          JS::GetProfilingCategoryPairInfo(mCategoryPair);
-      aWriter.IntElement(unsigned(info.mCategory));
-      // TODO: Store the callsite for this marker if available:
-      // if have location data
-      //   b.NameValue(marker, "location", ...);
-      if (mPayload) {
-        aWriter.StartObjectElement(SpliceableJSONWriter::SingleLineStyle);
-        { mPayload->StreamPayload(aWriter, aProcessStartTime, aUniqueStacks); }
-        aWriter.EndObject();
-      }
-    }
-    aWriter.EndArray();
-  }
-
- private:
-  mozilla::UniqueFreePtr<char> mMarkerName;
-  mozilla::UniquePtr<ProfilerMarkerPayload> mPayload;
-  ProfilerMarker* mNext;
-  double mTime;
-  uint64_t mPositionInBuffer;
-  int mThreadId;
-  JS::ProfilingCategoryPair mCategoryPair;
-};
-
-template <typename T>
-class ProfilerLinkedList {
- public:
-  ProfilerLinkedList() : mHead(nullptr), mTail(nullptr) {}
-
-  void insert(T* aElem) {
-    if (!mTail) {
-      mHead = aElem;
-      mTail = aElem;
-    } else {
-      mTail->mNext = aElem;
-      mTail = aElem;
-    }
-    aElem->mNext = nullptr;
-  }
-
-  T* popHead() {
-    if (!mHead) {
-      MOZ_ASSERT(false);
-      return nullptr;
-    }
-
-    T* head = mHead;
-
-    mHead = head->mNext;
-    if (!mHead) {
-      mTail = nullptr;
-    }
-
-    return head;
-  }
-
-  const T* peek() { return mHead; }
-
- private:
-  T* mHead;
-  T* mTail;
-};
-
-typedef ProfilerLinkedList<ProfilerMarker> ProfilerMarkerLinkedList;
-
-template <typename T>
-class ProfilerSignalSafeLinkedList {
- public:
-  ProfilerSignalSafeLinkedList() : mSignalLock(false) {}
-
-  ~ProfilerSignalSafeLinkedList() {
-    if (mSignalLock) {
-      // Some thread is modifying the list. We should only be released on that
-      // thread.
-      abort();
-    }
-
-    while (mList.peek()) {
-      delete mList.popHead();
-    }
-  }
-
-  // Insert an item into the list. Must only be called from the owning thread.
-  // Must not be called while the list from accessList() is being accessed.
-  // In the profiler, we ensure that by interrupting the profiled thread
-  // (which is the one that owns this list and calls insert() on it) until
-  // we're done reading the list from the signal handler.
-  void insert(T* aElement) {
-    MOZ_ASSERT(aElement);
-
-    mSignalLock = true;
-
-    mList.insert(aElement);
-
-    mSignalLock = false;
-  }
-
-  // Called within signal, from any thread, possibly while insert() is in the
-  // middle of modifying the list (on the owning thread). Will return null if
-  // that is the case.
-  // Function must be reentrant.
-  ProfilerLinkedList<T>* accessList() { return mSignalLock ? nullptr : &mList; }
-
- private:
-  ProfilerLinkedList<T> mList;
-
-  // If this is set, then it's not safe to read the list because its contents
-  // are being changed.
-  mozilla::Atomic<bool> mSignalLock;
-};
-
-#endif  // ProfilerMarker_h
diff --git a/tools/profiler/core/ProfilerMarkerPayload.cpp b/tools/profiler/core/ProfilerMarkerPayload.cpp
index c42da31c10..680a07644a 100644
--- a/tools/profiler/core/ProfilerMarkerPayload.cpp
+++ b/tools/profiler/core/ProfilerMarkerPayload.cpp
@@ -11,6 +11,7 @@
 
 #include "gfxASurface.h"
 #include "Layers.h"
+#include "mozilla/BlocksRingBufferGeckoExtensions.h"
 #include "mozilla/Maybe.h"
 #include "mozilla/net/HttpBaseChannel.h"
 #include "mozilla/Sprintf.h"
@@ -19,6 +20,75 @@
 
 using namespace mozilla;
 
+static UniquePtr<ProfilerMarkerPayload> DeserializeNothing(
+    BlocksRingBuffer::EntryReader&) {
+  return nullptr;
+}
+
+// Starting at 1 for the initial `DeserializeNothing`.
+// static
+Atomic<ProfilerMarkerPayload::DeserializerTagAtomic, ReleaseAcquire>
+    ProfilerMarkerPayload::sDeserializerCount{1};
+
+// Initialize `sDeserializers` with `DeserializeNothing` at index 0, all others
+// are nullptrs.
+// static
+ProfilerMarkerPayload::Deserializer
+    ProfilerMarkerPayload::sDeserializers[DeserializerMax] = {
+        DeserializeNothing};
+
+// static
+ProfilerMarkerPayload::DeserializerTag
+ProfilerMarkerPayload::TagForDeserializer(
+    ProfilerMarkerPayload::Deserializer aDeserializer) {
+  if (!aDeserializer) {
+    return 0;
+  }
+  // Start first search at index 0.
+  DeserializerTagAtomic start = 0;
+  for (;;) {
+    // Read the current count of deserializers.
+    const DeserializerTagAtomic tagCount = sDeserializerCount;
+    if (tagCount == 0) {
+      // Someone else is currently writing into the array, loop around until we
+      // get a valid count.
+      continue;
+    }
+    for (DeserializerTagAtomic i = start; i < tagCount; ++i) {
+      if (sDeserializers[i] == aDeserializer) {
+        // Deserializer already registered, return its tag.
+        return static_cast<ProfilerMarkerPayload::DeserializerTag>(i);
+      }
+    }
+    // Not found yet, let's register this new deserializer.
+    // Make sure we haven't reached the limit yet.
+    MOZ_RELEASE_ASSERT(tagCount < DeserializerMax);
+    // Reserve `tagCount` as an index, if not already claimed:
+    // If `sDeserializerCount` is still at our previously-read `tagCount`,
+    // replace it with a special 0 value to indicate a write.
+    if (sDeserializerCount.compareExchange(tagCount, 0)) {
+      // Here we own the `tagCount` index, write the deserializer there.
+      sDeserializers[tagCount] = aDeserializer;
+      // And publish by writing the real new count (1 past our index).
+      sDeserializerCount = tagCount + 1;
+      return static_cast<ProfilerMarkerPayload::DeserializerTag>(tagCount);
+    }
+    // Someone else beat us to grab an index, and it could be for the same
+    // deserializer! So let's just try searching starting from our recorded
+    // `tagCount` (and maybe attempting again to register). It should be rare
+    // enough and quick enough that it won't impact performances.
+    start = tagCount;
+  }
+}
+
+// static
+ProfilerMarkerPayload::Deserializer ProfilerMarkerPayload::DeserializerForTag(
+    ProfilerMarkerPayload::DeserializerTag aTag) {
+  MOZ_RELEASE_ASSERT(aTag < DeserializerMax);
+  MOZ_RELEASE_ASSERT(aTag < sDeserializerCount);
+  return sDeserializers[aTag];
+}
+
 static void MOZ_ALWAYS_INLINE WriteTime(SpliceableJSONWriter& aWriter,
                                         const TimeStamp& aProcessStartTime,
                                         const TimeStamp& aTime,
@@ -29,33 +99,103 @@ static void MOZ_ALWAYS_INLINE WriteTime(SpliceableJSONWriter& aWriter,
 }
 
 void ProfilerMarkerPayload::StreamType(const char* aMarkerType,
-                                       SpliceableJSONWriter& aWriter) {
+                                       SpliceableJSONWriter& aWriter) const {
   MOZ_ASSERT(aMarkerType);
   aWriter.StringProperty("type", aMarkerType);
 }
 
+BlocksRingBuffer::Length
+ProfilerMarkerPayload::CommonPropsTagAndSerializationBytes() const {
+  return sizeof(DeserializerTag) +
+         BlocksRingBuffer::SumBytes(mCommonProps.mStartTime,
+                                    mCommonProps.mEndTime, mCommonProps.mStack,
+                                    mCommonProps.mDocShellId,
+                                    mCommonProps.mDocShellHistoryId);
+}
+
+void ProfilerMarkerPayload::SerializeTagAndCommonProps(
+    DeserializerTag aDeserializerTag,
+    BlocksRingBuffer::EntryWriter& aEntryWriter) const {
+  aEntryWriter.WriteObject(aDeserializerTag);
+  aEntryWriter.WriteObject(mCommonProps.mStartTime);
+  aEntryWriter.WriteObject(mCommonProps.mEndTime);
+  aEntryWriter.WriteObject(mCommonProps.mStack);
+  aEntryWriter.WriteObject(mCommonProps.mDocShellId);
+  aEntryWriter.WriteObject(mCommonProps.mDocShellHistoryId);
+}
+
+// static
+ProfilerMarkerPayload::CommonProps
+ProfilerMarkerPayload::DeserializeCommonProps(
+    BlocksRingBuffer::EntryReader& aEntryReader) {
+  CommonProps props;
+  aEntryReader.ReadIntoObject(props.mStartTime);
+  aEntryReader.ReadIntoObject(props.mEndTime);
+  aEntryReader.ReadIntoObject(props.mStack);
+  aEntryReader.ReadIntoObject(props.mDocShellId);
+  aEntryReader.ReadIntoObject(props.mDocShellHistoryId);
+  return props;
+}
+
 void ProfilerMarkerPayload::StreamCommonProps(
     const char* aMarkerType, SpliceableJSONWriter& aWriter,
-    const TimeStamp& aProcessStartTime, UniqueStacks& aUniqueStacks) {
+    const TimeStamp& aProcessStartTime, UniqueStacks& aUniqueStacks) const {
   StreamType(aMarkerType, aWriter);
-  WriteTime(aWriter, aProcessStartTime, mStartTime, "startTime");
-  WriteTime(aWriter, aProcessStartTime, mEndTime, "endTime");
-  if (mDocShellId) {
-    aWriter.StringProperty("docShellId", nsIDToCString(*mDocShellId).get());
+  WriteTime(aWriter, aProcessStartTime, mCommonProps.mStartTime, "startTime");
+  WriteTime(aWriter, aProcessStartTime, mCommonProps.mEndTime, "endTime");
+  if (mCommonProps.mDocShellId) {
+    aWriter.StringProperty("docShellId",
+                           nsIDToCString(*mCommonProps.mDocShellId).get());
   }
-  if (mDocShellHistoryId) {
-    aWriter.DoubleProperty("docshellHistoryId", mDocShellHistoryId.ref());
+  if (mCommonProps.mDocShellHistoryId) {
+    aWriter.DoubleProperty("docshellHistoryId",
+                           mCommonProps.mDocShellHistoryId.ref());
   }
-  if (mStack) {
+  if (mCommonProps.mStack) {
     aWriter.StartObjectProperty("stack");
-    { mStack->StreamJSON(aWriter, aProcessStartTime, aUniqueStacks); }
+    {
+      mCommonProps.mStack->StreamJSON(aWriter, aProcessStartTime,
+                                      aUniqueStacks);
+    }
     aWriter.EndObject();
   }
 }
 
+BlocksRingBuffer::Length TracingMarkerPayload::TagAndSerializationBytes()
+    const {
+  return CommonPropsTagAndSerializationBytes() +
+         BlocksRingBuffer::SumBytes(WrapBlocksRingBufferRawPointer(mCategory),
+                                    mKind);
+}
+
+void TracingMarkerPayload::SerializeTagAndPayload(
+    BlocksRingBuffer::EntryWriter& aEntryWriter) const {
+  static const DeserializerTag tag = TagForDeserializer(Deserialize);
+  SerializeTagAndPayload(tag, aEntryWriter);
+}
+
+void TracingMarkerPayload::SerializeTagAndPayload(
+    DeserializerTag aDeserializerTag,
+    BlocksRingBuffer::EntryWriter& aEntryWriter) const {
+  SerializeTagAndCommonProps(aDeserializerTag, aEntryWriter);
+  aEntryWriter.WriteObject(WrapBlocksRingBufferRawPointer(mCategory));
+  aEntryWriter.WriteObject(mKind);
+}
+
+// static
+UniquePtr<ProfilerMarkerPayload> TracingMarkerPayload::Deserialize(
+    BlocksRingBuffer::EntryReader& aEntryReader) {
+  ProfilerMarkerPayload::CommonProps props =
+      DeserializeCommonProps(aEntryReader);
+  const char* category = aEntryReader.ReadObject<const char*>();
+  TracingKind kind = aEntryReader.ReadObject<TracingKind>();
+  return UniquePtr<ProfilerMarkerPayload>(
+      new TracingMarkerPayload(std::move(props), category, kind));
+}
+
 void TracingMarkerPayload::StreamPayload(SpliceableJSONWriter& aWriter,
                                          const TimeStamp& aProcessStartTime,
-                                         UniqueStacks& aUniqueStacks) {
+                                         UniqueStacks& aUniqueStacks) const {
   StreamCommonProps("tracing", aWriter, aProcessStartTime, aUniqueStacks);
 
   if (mCategory) {
@@ -69,9 +209,36 @@ void TracingMarkerPayload::StreamPayload(SpliceableJSONWriter& aWriter,
   }
 }
 
+BlocksRingBuffer::Length FileIOMarkerPayload::TagAndSerializationBytes() const {
+  return CommonPropsTagAndSerializationBytes() +
+         BlocksRingBuffer::SumBytes(WrapBlocksRingBufferRawPointer(mSource),
+                                    mOperation, mFilename);
+}
+
+void FileIOMarkerPayload::SerializeTagAndPayload(
+    BlocksRingBuffer::EntryWriter& aEntryWriter) const {
+  static const DeserializerTag tag = TagForDeserializer(Deserialize);
+  SerializeTagAndCommonProps(tag, aEntryWriter);
+  aEntryWriter.WriteObject(WrapBlocksRingBufferRawPointer(mSource));
+  aEntryWriter.WriteObject(mOperation);
+  aEntryWriter.WriteObject(mFilename);
+}
+
+// static
+UniquePtr<ProfilerMarkerPayload> FileIOMarkerPayload::Deserialize(
+    BlocksRingBuffer::EntryReader& aEntryReader) {
+  ProfilerMarkerPayload::CommonProps props =
+      DeserializeCommonProps(aEntryReader);
+  auto source = aEntryReader.ReadObject<const char*>();
+  auto operation = aEntryReader.ReadObject<UniqueFreePtr<char>>();
+  auto filename = aEntryReader.ReadObject<UniqueFreePtr<char>>();
+  return UniquePtr<ProfilerMarkerPayload>(new FileIOMarkerPayload(
+      std::move(props), source, std::move(operation), std::move(filename)));
+}
+
 void FileIOMarkerPayload::StreamPayload(SpliceableJSONWriter& aWriter,
                                         const TimeStamp& aProcessStartTime,
-                                        UniqueStacks& aUniqueStacks) {
+                                        UniqueStacks& aUniqueStacks) const {
   StreamCommonProps("FileIO", aWriter, aProcessStartTime, aUniqueStacks);
   aWriter.StringProperty("operation", mOperation.get());
   aWriter.StringProperty("source", mSource);
@@ -80,9 +247,40 @@ void FileIOMarkerPayload::StreamPayload(SpliceableJSONWriter& aWriter,
   }
 }
 
+BlocksRingBuffer::Length UserTimingMarkerPayload::TagAndSerializationBytes()
+    const {
+  return CommonPropsTagAndSerializationBytes() +
+         BlocksRingBuffer::SumBytes(WrapBlocksRingBufferRawPointer(mEntryType),
+                                    mName, mStartMark, mEndMark);
+}
+
+void UserTimingMarkerPayload::SerializeTagAndPayload(
+    BlocksRingBuffer::EntryWriter& aEntryWriter) const {
+  static const DeserializerTag tag = TagForDeserializer(Deserialize);
+  SerializeTagAndCommonProps(tag, aEntryWriter);
+  aEntryWriter.WriteObject(WrapBlocksRingBufferRawPointer(mEntryType));
+  aEntryWriter.WriteObject(mName);
+  aEntryWriter.WriteObject(mStartMark);
+  aEntryWriter.WriteObject(mEndMark);
+}
+
+// static
+UniquePtr<ProfilerMarkerPayload> UserTimingMarkerPayload::Deserialize(
+    BlocksRingBuffer::EntryReader& aEntryReader) {
+  ProfilerMarkerPayload::CommonProps props =
+      DeserializeCommonProps(aEntryReader);
+  auto entryType = aEntryReader.ReadObject<const char*>();
+  auto name = aEntryReader.ReadObject<nsString>();
+  auto startMark = aEntryReader.ReadObject<Maybe<nsString>>();
+  auto endMark = aEntryReader.ReadObject<Maybe<nsString>>();
+  return UniquePtr<ProfilerMarkerPayload>(
+      new UserTimingMarkerPayload(std::move(props), entryType, std::move(name),
+                                  std::move(startMark), std::move(endMark)));
+}
+
 void UserTimingMarkerPayload::StreamPayload(SpliceableJSONWriter& aWriter,
                                             const TimeStamp& aProcessStartTime,
-                                            UniqueStacks& aUniqueStacks) {
+                                            UniqueStacks& aUniqueStacks) const {
   StreamCommonProps("UserTiming", aWriter, aProcessStartTime, aUniqueStacks);
   aWriter.StringProperty("name", NS_ConvertUTF16toUTF8(mName).get());
   aWriter.StringProperty("entryType", mEntryType);
@@ -101,24 +299,99 @@ void UserTimingMarkerPayload::StreamPayload(SpliceableJSONWriter& aWriter,
   }
 }
 
+BlocksRingBuffer::Length TextMarkerPayload::TagAndSerializationBytes() const {
+  return CommonPropsTagAndSerializationBytes() +
+         BlocksRingBuffer::SumBytes(mText);
+}
+
+void TextMarkerPayload::SerializeTagAndPayload(
+    BlocksRingBuffer::EntryWriter& aEntryWriter) const {
+  static const DeserializerTag tag = TagForDeserializer(Deserialize);
+  SerializeTagAndCommonProps(tag, aEntryWriter);
+  aEntryWriter.WriteObject(mText);
+}
+
+// static
+UniquePtr<ProfilerMarkerPayload> TextMarkerPayload::Deserialize(
+    BlocksRingBuffer::EntryReader& aEntryReader) {
+  ProfilerMarkerPayload::CommonProps props =
+      DeserializeCommonProps(aEntryReader);
+  auto text = aEntryReader.ReadObject<nsCString>();
+  return UniquePtr<ProfilerMarkerPayload>(
+      new TextMarkerPayload(std::move(props), std::move(text)));
+}
+
 void TextMarkerPayload::StreamPayload(SpliceableJSONWriter& aWriter,
                                       const TimeStamp& aProcessStartTime,
-                                      UniqueStacks& aUniqueStacks) {
+                                      UniqueStacks& aUniqueStacks) const {
   StreamCommonProps("Text", aWriter, aProcessStartTime, aUniqueStacks);
   aWriter.StringProperty("name", mText.get());
 }
 
+BlocksRingBuffer::Length LogMarkerPayload::TagAndSerializationBytes() const {
+  return CommonPropsTagAndSerializationBytes() +
+         BlocksRingBuffer::SumBytes(mModule, mText);
+}
+
+void LogMarkerPayload::SerializeTagAndPayload(
+    BlocksRingBuffer::EntryWriter& aEntryWriter) const {
+  static const DeserializerTag tag = TagForDeserializer(Deserialize);
+  SerializeTagAndCommonProps(tag, aEntryWriter);
+  aEntryWriter.WriteObject(mModule);
+  aEntryWriter.WriteObject(mText);
+}
+
+// static
+UniquePtr<ProfilerMarkerPayload> LogMarkerPayload::Deserialize(
+    BlocksRingBuffer::EntryReader& aEntryReader) {
+  ProfilerMarkerPayload::CommonProps props =
+      DeserializeCommonProps(aEntryReader);
+  auto module = aEntryReader.ReadObject<nsAutoCStringN<32>>();
+  auto text = aEntryReader.ReadObject<nsCString>();
+  return UniquePtr<ProfilerMarkerPayload>(new LogMarkerPayload(
+      std::move(props), std::move(module), std::move(text)));
+}
+
 void LogMarkerPayload::StreamPayload(SpliceableJSONWriter& aWriter,
                                      const TimeStamp& aProcessStartTime,
-                                     UniqueStacks& aUniqueStacks) {
+                                     UniqueStacks& aUniqueStacks) const {
   StreamCommonProps("Log", aWriter, aProcessStartTime, aUniqueStacks);
   aWriter.StringProperty("name", mText.get());
   aWriter.StringProperty("module", mModule.get());
 }
 
+BlocksRingBuffer::Length DOMEventMarkerPayload::TagAndSerializationBytes()
+    const {
+  return TracingMarkerPayload::TagAndSerializationBytes() +
+         BlocksRingBuffer::SumBytes(mTimeStamp, mEventType);
+}
+
+void DOMEventMarkerPayload::SerializeTagAndPayload(
+    BlocksRingBuffer::EntryWriter& aEntryWriter) const {
+  static const DeserializerTag tag = TagForDeserializer(Deserialize);
+  // Let our parent class serialize our tag with its payload.
+  TracingMarkerPayload::SerializeTagAndPayload(tag, aEntryWriter);
+  // Then write our extra data.
+  aEntryWriter.WriteObject(mTimeStamp);
+  aEntryWriter.WriteObject(mEventType);
+}
+
+// static
+UniquePtr<ProfilerMarkerPayload> DOMEventMarkerPayload::Deserialize(
+    BlocksRingBuffer::EntryReader& aEntryReader) {
+  ProfilerMarkerPayload::CommonProps props =
+      DeserializeCommonProps(aEntryReader);
+  const char* category = aEntryReader.ReadObject<const char*>();
+  TracingKind kind = aEntryReader.ReadObject<TracingKind>();
+  auto timeStamp = aEntryReader.ReadObject<TimeStamp>();
+  auto eventType = aEntryReader.ReadObject<nsString>();
+  return UniquePtr<ProfilerMarkerPayload>(new DOMEventMarkerPayload(
+      std::move(props), category, kind, timeStamp, std::move(eventType)));
+}
+
 void DOMEventMarkerPayload::StreamPayload(SpliceableJSONWriter& aWriter,
                                           const TimeStamp& aProcessStartTime,
-                                          UniqueStacks& aUniqueStacks) {
+                                          UniqueStacks& aUniqueStacks) const {
   TracingMarkerPayload::StreamPayload(aWriter, aProcessStartTime,
                                       aUniqueStacks);
 
@@ -126,9 +399,35 @@ void DOMEventMarkerPayload::StreamPayload(SpliceableJSONWriter& aWriter,
   aWriter.StringProperty("eventType", NS_ConvertUTF16toUTF8(mEventType).get());
 }
 
+BlocksRingBuffer::Length
+LayerTranslationMarkerPayload::TagAndSerializationBytes() const {
+  return CommonPropsTagAndSerializationBytes() +
+         BlocksRingBuffer::SumBytes(WrapBlocksRingBufferRawPointer(mLayer),
+                                    mPoint);
+}
+
+void LayerTranslationMarkerPayload::SerializeTagAndPayload(
+    BlocksRingBuffer::EntryWriter& aEntryWriter) const {
+  static const DeserializerTag tag = TagForDeserializer(Deserialize);
+  SerializeTagAndCommonProps(tag, aEntryWriter);
+  aEntryWriter.WriteObject(WrapBlocksRingBufferRawPointer(mLayer));
+  aEntryWriter.WriteObject(mPoint);
+}
+
+// static
+UniquePtr<ProfilerMarkerPayload> LayerTranslationMarkerPayload::Deserialize(
+    BlocksRingBuffer::EntryReader& aEntryReader) {
+  ProfilerMarkerPayload::CommonProps props =
+      DeserializeCommonProps(aEntryReader);
+  auto layer = aEntryReader.ReadObject<layers::Layer*>();
+  auto point = aEntryReader.ReadObject<gfx::Point>();
+  return UniquePtr<ProfilerMarkerPayload>(
+      new LayerTranslationMarkerPayload(std::move(props), layer, point));
+}
+
 void LayerTranslationMarkerPayload::StreamPayload(
     SpliceableJSONWriter& aWriter, const TimeStamp& aProcessStartTime,
-    UniqueStacks& aUniqueStacks) {
+    UniqueStacks& aUniqueStacks) const {
   StreamType("LayerTranslation", aWriter);
   const size_t bufferSize = 32;
   char buffer[bufferSize];
@@ -139,12 +438,70 @@ void LayerTranslationMarkerPayload::StreamPayload(
   aWriter.IntProperty("y", mPoint.y);
 }
 
+BlocksRingBuffer::Length VsyncMarkerPayload::TagAndSerializationBytes() const {
+  return CommonPropsTagAndSerializationBytes();
+}
+
+void VsyncMarkerPayload::SerializeTagAndPayload(
+    BlocksRingBuffer::EntryWriter& aEntryWriter) const {
+  static const DeserializerTag tag = TagForDeserializer(Deserialize);
+  SerializeTagAndCommonProps(tag, aEntryWriter);
+}
+
+// static
+UniquePtr<ProfilerMarkerPayload> VsyncMarkerPayload::Deserialize(
+    BlocksRingBuffer::EntryReader& aEntryReader) {
+  ProfilerMarkerPayload::CommonProps props =
+      DeserializeCommonProps(aEntryReader);
+  return UniquePtr<ProfilerMarkerPayload>(
+      new VsyncMarkerPayload(std::move(props)));
+}
+
 void VsyncMarkerPayload::StreamPayload(SpliceableJSONWriter& aWriter,
                                        const TimeStamp& aProcessStartTime,
-                                       UniqueStacks& aUniqueStacks) {
+                                       UniqueStacks& aUniqueStacks) const {
   StreamType("VsyncTimestamp", aWriter);
 }
 
+BlocksRingBuffer::Length NetworkMarkerPayload::TagAndSerializationBytes()
+    const {
+  return CommonPropsTagAndSerializationBytes() +
+         BlocksRingBuffer::SumBytes(mID, mURI, mRedirectURI, mType, mPri,
+                                    mCount, mTimings, mCacheDisposition);
+}
+
+void NetworkMarkerPayload::SerializeTagAndPayload(
+    BlocksRingBuffer::EntryWriter& aEntryWriter) const {
+  static const DeserializerTag tag = TagForDeserializer(Deserialize);
+  SerializeTagAndCommonProps(tag, aEntryWriter);
+  aEntryWriter.WriteObject(mID);
+  aEntryWriter.WriteObject(mURI);
+  aEntryWriter.WriteObject(mRedirectURI);
+  aEntryWriter.WriteObject(mType);
+  aEntryWriter.WriteObject(mPri);
+  aEntryWriter.WriteObject(mCount);
+  aEntryWriter.WriteObject(mTimings);
+  aEntryWriter.WriteObject(mCacheDisposition);
+}
+
+// static
+UniquePtr<ProfilerMarkerPayload> NetworkMarkerPayload::Deserialize(
+    BlocksRingBuffer::EntryReader& aEntryReader) {
+  ProfilerMarkerPayload::CommonProps props =
+      DeserializeCommonProps(aEntryReader);
+  auto id = aEntryReader.ReadObject<int64_t>();
+  auto uri = aEntryReader.ReadObject<UniqueFreePtr<char>>();
+  auto redirectURI = aEntryReader.ReadObject<UniqueFreePtr<char>>();
+  auto type = aEntryReader.ReadObject<NetworkLoadType>();
+  auto pri = aEntryReader.ReadObject<int32_t>();
+  auto count = aEntryReader.ReadObject<int64_t>();
+  auto timings = aEntryReader.ReadObject<net::TimingStruct>();
+  auto cacheDisposition = aEntryReader.ReadObject<net::CacheDisposition>();
+  return UniquePtr<ProfilerMarkerPayload>(new NetworkMarkerPayload(
+      std::move(props), id, std::move(uri), std::move(redirectURI), type, pri,
+      count, timings, cacheDisposition));
+}
+
 static const char* GetNetworkState(NetworkLoadType aType) {
   switch (aType) {
     case NetworkLoadType::LOAD_START:
@@ -157,20 +514,19 @@ static const char* GetNetworkState(NetworkLoadType aType) {
   return "";
 }
 
-static const char* GetCacheState(
-    mozilla::net::CacheDisposition aCacheDisposition) {
+static const char* GetCacheState(net::CacheDisposition aCacheDisposition) {
   switch (aCacheDisposition) {
-    case mozilla::net::kCacheUnresolved:
+    case net::kCacheUnresolved:
       return "Unresolved";
-    case mozilla::net::kCacheHit:
+    case net::kCacheHit:
       return "Hit";
-    case mozilla::net::kCacheHitViaReval:
+    case net::kCacheHitViaReval:
       return "HitViaReval";
-    case mozilla::net::kCacheMissedViaReval:
+    case net::kCacheMissedViaReval:
       return "MissedViaReval";
-    case mozilla::net::kCacheMissed:
+    case net::kCacheMissed:
       return "Missed";
-    case mozilla::net::kCacheUnknown:
+    case net::kCacheUnknown:
     default:
       return nullptr;
   }
@@ -178,7 +534,7 @@ static const char* GetCacheState(
 
 void NetworkMarkerPayload::StreamPayload(SpliceableJSONWriter& aWriter,
                                          const TimeStamp& aProcessStartTime,
-                                         UniqueStacks& aUniqueStacks) {
+                                         UniqueStacks& aUniqueStacks) const {
   StreamCommonProps("Network", aWriter, aProcessStartTime, aUniqueStacks);
   aWriter.IntProperty("id", mID);
   const char* typeString = GetNetworkState(mType);
@@ -219,9 +575,37 @@ void NetworkMarkerPayload::StreamPayload(SpliceableJSONWriter& aWriter,
   }
 }
 
+BlocksRingBuffer::Length ScreenshotPayload::TagAndSerializationBytes() const {
+  return CommonPropsTagAndSerializationBytes() +
+         BlocksRingBuffer::SumBytes(mScreenshotDataURL, mWindowSize,
+                                    mWindowIdentifier);
+}
+
+void ScreenshotPayload::SerializeTagAndPayload(
+    BlocksRingBuffer::EntryWriter& aEntryWriter) const {
+  static const DeserializerTag tag = TagForDeserializer(Deserialize);
+  SerializeTagAndCommonProps(tag, aEntryWriter);
+  aEntryWriter.WriteObject(mScreenshotDataURL);
+  aEntryWriter.WriteObject(mWindowSize);
+  aEntryWriter.WriteObject(mWindowIdentifier);
+}
+
+// static
+UniquePtr<ProfilerMarkerPayload> ScreenshotPayload::Deserialize(
+    BlocksRingBuffer::EntryReader& aEntryReader) {
+  ProfilerMarkerPayload::CommonProps props =
+      DeserializeCommonProps(aEntryReader);
+  auto screenshotDataURL = aEntryReader.ReadObject<nsCString>();
+  auto windowSize = aEntryReader.ReadObject<gfx::IntSize>();
+  auto windowIdentifier = aEntryReader.ReadObject<uintptr_t>();
+  return UniquePtr<ProfilerMarkerPayload>(
+      new ScreenshotPayload(std::move(props), std::move(screenshotDataURL),
+                            windowSize, windowIdentifier));
+}
+
 void ScreenshotPayload::StreamPayload(SpliceableJSONWriter& aWriter,
                                       const TimeStamp& aProcessStartTime,
-                                      UniqueStacks& aUniqueStacks) {
+                                      UniqueStacks& aUniqueStacks) const {
   StreamType("CompositorScreenshot", aWriter);
   aUniqueStacks.mUniqueStrings->WriteProperty(aWriter, "url",
                                               mScreenshotDataURL.get());
@@ -233,9 +617,32 @@ void ScreenshotPayload::StreamPayload(SpliceableJSONWriter& aWriter,
   aWriter.DoubleProperty("windowHeight", mWindowSize.height);
 }
 
+BlocksRingBuffer::Length GCSliceMarkerPayload::TagAndSerializationBytes()
+    const {
+  return CommonPropsTagAndSerializationBytes() +
+         BlocksRingBuffer::SumBytes(mTimingJSON);
+}
+
+void GCSliceMarkerPayload::SerializeTagAndPayload(
+    BlocksRingBuffer::EntryWriter& aEntryWriter) const {
+  static const DeserializerTag tag = TagForDeserializer(Deserialize);
+  SerializeTagAndCommonProps(tag, aEntryWriter);
+  aEntryWriter.WriteObject(mTimingJSON);
+}
+
+// static
+UniquePtr<ProfilerMarkerPayload> GCSliceMarkerPayload::Deserialize(
+    BlocksRingBuffer::EntryReader& aEntryReader) {
+  ProfilerMarkerPayload::CommonProps props =
+      DeserializeCommonProps(aEntryReader);
+  auto timingJSON = aEntryReader.ReadObject<JS::UniqueChars>();
+  return UniquePtr<ProfilerMarkerPayload>(
+      new GCSliceMarkerPayload(std::move(props), std::move(timingJSON)));
+}
+
 void GCSliceMarkerPayload::StreamPayload(SpliceableJSONWriter& aWriter,
                                          const TimeStamp& aProcessStartTime,
-                                         UniqueStacks& aUniqueStacks) {
+                                         UniqueStacks& aUniqueStacks) const {
   MOZ_ASSERT(mTimingJSON);
   StreamCommonProps("GCSlice", aWriter, aProcessStartTime, aUniqueStacks);
   if (mTimingJSON) {
@@ -245,9 +652,32 @@ void GCSliceMarkerPayload::StreamPayload(SpliceableJSONWriter& aWriter,
   }
 }
 
+BlocksRingBuffer::Length GCMajorMarkerPayload::TagAndSerializationBytes()
+    const {
+  return CommonPropsTagAndSerializationBytes() +
+         BlocksRingBuffer::SumBytes(mTimingJSON);
+}
+
+void GCMajorMarkerPayload::SerializeTagAndPayload(
+    BlocksRingBuffer::EntryWriter& aEntryWriter) const {
+  static const DeserializerTag tag = TagForDeserializer(Deserialize);
+  SerializeTagAndCommonProps(tag, aEntryWriter);
+  aEntryWriter.WriteObject(mTimingJSON);
+}
+
+// static
+UniquePtr<ProfilerMarkerPayload> GCMajorMarkerPayload::Deserialize(
+    BlocksRingBuffer::EntryReader& aEntryReader) {
+  ProfilerMarkerPayload::CommonProps props =
+      DeserializeCommonProps(aEntryReader);
+  auto timingJSON = aEntryReader.ReadObject<JS::UniqueChars>();
+  return UniquePtr<ProfilerMarkerPayload>(
+      new GCMajorMarkerPayload(std::move(props), std::move(timingJSON)));
+}
+
 void GCMajorMarkerPayload::StreamPayload(SpliceableJSONWriter& aWriter,
                                          const TimeStamp& aProcessStartTime,
-                                         UniqueStacks& aUniqueStacks) {
+                                         UniqueStacks& aUniqueStacks) const {
   MOZ_ASSERT(mTimingJSON);
   StreamCommonProps("GCMajor", aWriter, aProcessStartTime, aUniqueStacks);
   if (mTimingJSON) {
@@ -257,9 +687,32 @@ void GCMajorMarkerPayload::StreamPayload(SpliceableJSONWriter& aWriter,
   }
 }
 
+BlocksRingBuffer::Length GCMinorMarkerPayload::TagAndSerializationBytes()
+    const {
+  return CommonPropsTagAndSerializationBytes() +
+         BlocksRingBuffer::SumBytes(mTimingData);
+}
+
+void GCMinorMarkerPayload::SerializeTagAndPayload(
+    BlocksRingBuffer::EntryWriter& aEntryWriter) const {
+  static const DeserializerTag tag = TagForDeserializer(Deserialize);
+  SerializeTagAndCommonProps(tag, aEntryWriter);
+  aEntryWriter.WriteObject(mTimingData);
+}
+
+// static
+UniquePtr<ProfilerMarkerPayload> GCMinorMarkerPayload::Deserialize(
+    BlocksRingBuffer::EntryReader& aEntryReader) {
+  ProfilerMarkerPayload::CommonProps props =
+      DeserializeCommonProps(aEntryReader);
+  auto timingData = aEntryReader.ReadObject<JS::UniqueChars>();
+  return UniquePtr<ProfilerMarkerPayload>(
+      new GCMinorMarkerPayload(std::move(props), std::move(timingData)));
+}
+
 void GCMinorMarkerPayload::StreamPayload(SpliceableJSONWriter& aWriter,
                                          const TimeStamp& aProcessStartTime,
-                                         UniqueStacks& aUniqueStacks) {
+                                         UniqueStacks& aUniqueStacks) const {
   MOZ_ASSERT(mTimingData);
   StreamCommonProps("GCMinor", aWriter, aProcessStartTime, aUniqueStacks);
   if (mTimingData) {
@@ -269,16 +722,57 @@ void GCMinorMarkerPayload::StreamPayload(SpliceableJSONWriter& aWriter,
   }
 }
 
+BlocksRingBuffer::Length HangMarkerPayload::TagAndSerializationBytes() const {
+  return CommonPropsTagAndSerializationBytes();
+}
+
+void HangMarkerPayload::SerializeTagAndPayload(
+    BlocksRingBuffer::EntryWriter& aEntryWriter) const {
+  static const DeserializerTag tag = TagForDeserializer(Deserialize);
+  SerializeTagAndCommonProps(tag, aEntryWriter);
+}
+
+// static
+UniquePtr<ProfilerMarkerPayload> HangMarkerPayload::Deserialize(
+    BlocksRingBuffer::EntryReader& aEntryReader) {
+  ProfilerMarkerPayload::CommonProps props =
+      DeserializeCommonProps(aEntryReader);
+  return UniquePtr<ProfilerMarkerPayload>(
+      new HangMarkerPayload(std::move(props)));
+}
+
 void HangMarkerPayload::StreamPayload(SpliceableJSONWriter& aWriter,
                                       const TimeStamp& aProcessStartTime,
-                                      UniqueStacks& aUniqueStacks) {
+                                      UniqueStacks& aUniqueStacks) const {
   StreamCommonProps("BHR-detected hang", aWriter, aProcessStartTime,
                     aUniqueStacks);
 }
 
+BlocksRingBuffer::Length StyleMarkerPayload::TagAndSerializationBytes() const {
+  return CommonPropsTagAndSerializationBytes() +
+         BlocksRingBuffer::SumBytes(mStats);
+}
+
+void StyleMarkerPayload::SerializeTagAndPayload(
+    BlocksRingBuffer::EntryWriter& aEntryWriter) const {
+  static const DeserializerTag tag = TagForDeserializer(Deserialize);
+  SerializeTagAndCommonProps(tag, aEntryWriter);
+  aEntryWriter.WriteObject(mStats);
+}
+
+// static
+UniquePtr<ProfilerMarkerPayload> StyleMarkerPayload::Deserialize(
+    BlocksRingBuffer::EntryReader& aEntryReader) {
+  ProfilerMarkerPayload::CommonProps props =
+      DeserializeCommonProps(aEntryReader);
+  auto stats = aEntryReader.ReadObject<ServoTraversalStatistics>();
+  return UniquePtr<ProfilerMarkerPayload>(
+      new StyleMarkerPayload(std::move(props), stats));
+}
+
 void StyleMarkerPayload::StreamPayload(SpliceableJSONWriter& aWriter,
                                        const TimeStamp& aProcessStartTime,
-                                       UniqueStacks& aUniqueStacks) {
+                                       UniqueStacks& aUniqueStacks) const {
   StreamCommonProps("Styles", aWriter, aProcessStartTime, aUniqueStacks);
   aWriter.StringProperty("category", "Paint");
   aWriter.IntProperty("elementsTraversed", mStats.mElementsTraversed);
@@ -288,25 +782,78 @@ void StyleMarkerPayload::StreamPayload(SpliceableJSONWriter& aWriter,
   aWriter.IntProperty("stylesReused", mStats.mStylesReused);
 }
 
+BlocksRingBuffer::Length LongTaskMarkerPayload::TagAndSerializationBytes()
+    const {
+  return CommonPropsTagAndSerializationBytes();
+}
+
+void LongTaskMarkerPayload::SerializeTagAndPayload(
+    BlocksRingBuffer::EntryWriter& aEntryWriter) const {
+  static const DeserializerTag tag = TagForDeserializer(Deserialize);
+  SerializeTagAndCommonProps(tag, aEntryWriter);
+}
+
+// static
+UniquePtr<ProfilerMarkerPayload> LongTaskMarkerPayload::Deserialize(
+    BlocksRingBuffer::EntryReader& aEntryReader) {
+  ProfilerMarkerPayload::CommonProps props =
+      DeserializeCommonProps(aEntryReader);
+  return UniquePtr<ProfilerMarkerPayload>(
+      new LongTaskMarkerPayload(std::move(props)));
+}
+
 void LongTaskMarkerPayload::StreamPayload(SpliceableJSONWriter& aWriter,
                                           const TimeStamp& aProcessStartTime,
-                                          UniqueStacks& aUniqueStacks) {
+                                          UniqueStacks& aUniqueStacks) const {
   StreamCommonProps("MainThreadLongTask", aWriter, aProcessStartTime,
                     aUniqueStacks);
   aWriter.StringProperty("category", "LongTask");
 }
 
+BlocksRingBuffer::Length JsAllocationMarkerPayload::TagAndSerializationBytes()
+    const {
+  return CommonPropsTagAndSerializationBytes() +
+         BlocksRingBuffer::SumBytes(mTypeName, mClassName, mDescriptiveTypeName,
+                                    mCoarseType, mSize, mInNursery);
+}
+
+void JsAllocationMarkerPayload::SerializeTagAndPayload(
+    BlocksRingBuffer::EntryWriter& aEntryWriter) const {
+  static const DeserializerTag tag = TagForDeserializer(Deserialize);
+  SerializeTagAndCommonProps(tag, aEntryWriter);
+  aEntryWriter.WriteObject(mTypeName);
+  aEntryWriter.WriteObject(mClassName);
+  aEntryWriter.WriteObject(mDescriptiveTypeName);
+  aEntryWriter.WriteObject(WrapBlocksRingBufferRawPointer(mCoarseType));
+  aEntryWriter.WriteObject(mSize);
+  aEntryWriter.WriteObject(mInNursery);
+}
+
+// static
+UniquePtr<ProfilerMarkerPayload> JsAllocationMarkerPayload::Deserialize(
+    BlocksRingBuffer::EntryReader& aEntryReader) {
+  ProfilerMarkerPayload::CommonProps props =
+      DeserializeCommonProps(aEntryReader);
+  auto typeName = aEntryReader.ReadObject<UniqueFreePtr<const char16_t>>();
+  auto className = aEntryReader.ReadObject<UniqueFreePtr<const char>>();
+  auto descriptiveTypeName =
+      aEntryReader.ReadObject<UniqueFreePtr<const char16_t>>();
+  auto coarseType = aEntryReader.ReadObject<const char*>();
+  auto size = aEntryReader.ReadObject<uint64_t>();
+  auto inNursery = aEntryReader.ReadObject<bool>();
+  return UniquePtr<ProfilerMarkerPayload>(new JsAllocationMarkerPayload(
+      std::move(props), std::move(typeName), std::move(className),
+      std::move(descriptiveTypeName), coarseType, size, inNursery));
+}
+
 void JsAllocationMarkerPayload::StreamPayload(
     SpliceableJSONWriter& aWriter, const TimeStamp& aProcessStartTime,
-    UniqueStacks& aUniqueStacks) {
+    UniqueStacks& aUniqueStacks) const {
   StreamCommonProps("JS allocation", aWriter, aProcessStartTime, aUniqueStacks);
 
   if (mClassName) {
     aWriter.StringProperty("className", mClassName.get());
   }
-  if (mScriptFilename) {
-    aWriter.StringProperty("scriptFilename", mScriptFilename.get());
-  }
   if (mTypeName) {
     aWriter.StringProperty("typeName",
                            NS_ConvertUTF16toUTF8(mTypeName.get()).get());
@@ -320,3 +867,34 @@ void JsAllocationMarkerPayload::StreamPayload(
   aWriter.IntProperty("size", mSize);
   aWriter.BoolProperty("inNursery", mInNursery);
 }
+
+BlocksRingBuffer::Length
+NativeAllocationMarkerPayload::TagAndSerializationBytes() const {
+  return CommonPropsTagAndSerializationBytes() +
+         BlocksRingBuffer::SumBytes(mSize);
+}
+
+void NativeAllocationMarkerPayload::SerializeTagAndPayload(
+    BlocksRingBuffer::EntryWriter& aEntryWriter) const {
+  static const DeserializerTag tag = TagForDeserializer(Deserialize);
+  SerializeTagAndCommonProps(tag, aEntryWriter);
+  aEntryWriter.WriteObject(mSize);
+}
+
+// static
+UniquePtr<ProfilerMarkerPayload> NativeAllocationMarkerPayload::Deserialize(
+    BlocksRingBuffer::EntryReader& aEntryReader) {
+  ProfilerMarkerPayload::CommonProps props =
+      DeserializeCommonProps(aEntryReader);
+  auto size = aEntryReader.ReadObject<int64_t>();
+  return UniquePtr<ProfilerMarkerPayload>(
+      new NativeAllocationMarkerPayload(std::move(props), size));
+}
+
+void NativeAllocationMarkerPayload::StreamPayload(
+    SpliceableJSONWriter& aWriter, const TimeStamp& aProcessStartTime,
+    UniqueStacks& aUniqueStacks) const {
+  StreamCommonProps("Native allocation", aWriter, aProcessStartTime,
+                    aUniqueStacks);
+  aWriter.IntProperty("size", mSize);
+}
diff --git a/tools/profiler/core/RegisteredThread.cpp b/tools/profiler/core/RegisteredThread.cpp
index d3f084b5da..618f2c8dfb 100644
--- a/tools/profiler/core/RegisteredThread.cpp
+++ b/tools/profiler/core/RegisteredThread.cpp
@@ -4,7 +4,7 @@
 
 #include "RegisteredThread.h"
 
-RegisteredThread::RegisteredThread(ThreadInfo* aInfo, nsIEventTarget* aThread,
+RegisteredThread::RegisteredThread(ThreadInfo* aInfo, nsIThread* aThread,
                                    void* aStackTop)
     : mRacyRegisteredThread(aInfo->ThreadId()),
       mPlatformData(AllocPlatformData(aInfo->ThreadId())),
@@ -16,6 +16,9 @@ RegisteredThread::RegisteredThread(ThreadInfo* aInfo, nsIEventTarget* aThread,
       mJSFlags(0) {
   MOZ_COUNT_CTOR(RegisteredThread);
 
+  // NOTE: aThread can be null for the first thread, before the ThreadManager
+  // is initialized.
+
   // We don't have to guess on mac
 #if defined(GP_OS_darwin)
   pthread_t self = pthread_self();
@@ -39,3 +42,21 @@ size_t RegisteredThread::SizeOfIncludingThis(
 
   return n;
 }
+
+void RegisteredThread::GetRunningEventDelay(const TimeStamp& aNow,
+                                            TimeDuration& aDelay,
+                                            TimeDuration& aRunning) {
+  if (mThread) {  // can be null right at the start of a process
+    TimeStamp start;
+    mThread->GetRunningEventDelay(&aDelay, &start);
+    if (!start.IsNull()) {
+      // Note: the timestamp used here will be from when we started to
+      // suspend and sample the thread; which is also the timestamp
+      // associated with the sample.
+      aRunning = aNow - start;
+      return;
+    }
+  }
+  aDelay = TimeDuration();
+  aRunning = TimeDuration();
+}
diff --git a/tools/profiler/core/RegisteredThread.h b/tools/profiler/core/RegisteredThread.h
index eba12150c3..e63f546dac 100644
--- a/tools/profiler/core/RegisteredThread.h
+++ b/tools/profiler/core/RegisteredThread.h
@@ -6,8 +6,6 @@
 #define RegisteredThread_h
 
 #include "platform.h"
-#include "ProfilerMarker.h"
-#include "ProfilerMarkerPayload.h"
 #include "ThreadInfo.h"
 
 #include "js/TraceLoggerAPI.h"
@@ -35,25 +33,6 @@ class RacyRegisteredThread final {
 
   bool IsBeingProfiled() const { return mIsBeingProfiled; }
 
-  void AddPendingMarker(const char* aMarkerName,
-                        JS::ProfilingCategoryPair aCategoryPair,
-                        mozilla::UniquePtr<ProfilerMarkerPayload> aPayload,
-                        double aTime) {
-    // Note: We don't assert on mIsBeingProfiled, because it could have changed
-    // between the check in the caller and now.
-    ProfilerMarker* marker = new ProfilerMarker(
-        aMarkerName, aCategoryPair, mThreadId, std::move(aPayload), aTime);
-    mPendingMarkers.insert(marker);
-  }
-
-  // Called within signal. Function must be reentrant.
-  ProfilerMarkerLinkedList* GetPendingMarkers() {
-    // The profiled thread is interrupted, so we can access the list safely.
-    // Unless the profiled thread was in the middle of changing the list when
-    // we interrupted it - in that case, accessList() will return null.
-    return mPendingMarkers.accessList();
-  }
-
   // This is called on every profiler restart. Put things that should happen at
   // that time here.
   void ReinitializeOnResume() {
@@ -103,9 +82,6 @@ class RacyRegisteredThread final {
  private:
   class ProfilingStack mProfilingStack;
 
-  // A list of pending markers that must be moved to the circular buffer.
-  ProfilerSignalSafeLinkedList<ProfilerMarker> mPendingMarkers;
-
   // mThreadId contains the thread ID of the current thread. It is safe to read
   // this from multiple threads concurrently, as it will never be mutated.
   const int mThreadId;
@@ -158,7 +134,7 @@ class RacyRegisteredThread final {
 // protected by the profiler state lock.
 class RegisteredThread final {
  public:
-  RegisteredThread(ThreadInfo* aInfo, nsIEventTarget* aThread, void* aStackTop);
+  RegisteredThread(ThreadInfo* aInfo, nsIThread* aThread, void* aStackTop);
   ~RegisteredThread();
 
   class RacyRegisteredThread& RacyRegisteredThread() {
@@ -171,6 +147,16 @@ class RegisteredThread final {
   PlatformData* GetPlatformData() const { return mPlatformData.get(); }
   const void* StackTop() const { return mStackTop; }
 
+  // aDelay is the time the event that is currently running on the thread
+  // was queued before starting to run (if a PrioritizedEventQueue
+  // (i.e. MainThread), this will be 0 for any event at a lower priority
+  // than Input).
+  // aRunning is the time the event has been running.  If no event is
+  // running these will both be TimeDuration() (i.e. 0).  Both are out
+  // params, and are always set.  Their initial value is discarded.
+  void GetRunningEventDelay(const TimeStamp& aNow, TimeDuration& aDelay,
+                            TimeDuration& aRunning);
+
   size_t SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const;
 
   // Set the JSContext of the thread to be sampled. Sampling cannot begin until
@@ -197,6 +183,7 @@ class RegisteredThread final {
 
   const RefPtr<ThreadInfo> Info() const { return mThreadInfo; }
   const nsCOMPtr<nsIEventTarget> GetEventTarget() const { return mThread; }
+  void ResetMainThread(nsIThread* aThread) { mThread = aThread; }
 
   // Request that this thread start JS sampling. JS sampling won't actually
   // start until a subsequent PollJSSampling() call occurs *and* mContext has
@@ -269,7 +256,7 @@ class RegisteredThread final {
   const void* mStackTop;
 
   const RefPtr<ThreadInfo> mThreadInfo;
-  const nsCOMPtr<nsIEventTarget> mThread;
+  nsCOMPtr<nsIThread> mThread;
 
   // If this is a JS thread, this is its JSContext, which is required for any
   // JS sampling.
@@ -324,10 +311,6 @@ class RegisteredThread final {
 
   uint32_t mJSFlags;
 
-  bool TrackOptimizationsEnabled() {
-    return mJSFlags & uint32_t(JSInstrumentationFlags::TrackOptimizations);
-  }
-
   bool JSTracerEnabled() {
     return mJSFlags & uint32_t(JSInstrumentationFlags::TraceLogging);
   }
diff --git a/tools/profiler/core/ThreadInfo.h b/tools/profiler/core/ThreadInfo.h
index 0f87b8f285..1506e034cf 100644
--- a/tools/profiler/core/ThreadInfo.h
+++ b/tools/profiler/core/ThreadInfo.h
@@ -17,9 +17,9 @@ class ThreadInfo final {
  public:
   NS_INLINE_DECL_THREADSAFE_REFCOUNTING(ThreadInfo)
 
-  ThreadInfo(
-      const char* aName, int aThreadId, bool aIsMainThread,
-      const mozilla::TimeStamp& aRegisterTime = mozilla::TimeStamp::Now())
+  ThreadInfo(const char* aName, int aThreadId, bool aIsMainThread,
+             const mozilla::TimeStamp& aRegisterTime =
+                 mozilla::TimeStamp::NowUnfuzzed())
       : mName(aName),
         mRegisterTime(aRegisterTime),
         mThreadId(aThreadId),
diff --git a/tools/profiler/core/memory_hooks.cpp b/tools/profiler/core/memory_hooks.cpp
index 8fe45f826c..1c86c0bb76 100644
--- a/tools/profiler/core/memory_hooks.cpp
+++ b/tools/profiler/core/memory_hooks.cpp
@@ -7,11 +7,16 @@
 #include "nscore.h"
 
 #include "mozilla/Assertions.h"
+#include "mozilla/Atomics.h"
+#include "mozilla/FastBernoulliTrial.h"
 #include "mozilla/IntegerPrintfMacros.h"
 #include "mozilla/JSONWriter.h"
 #include "mozilla/MemoryReporting.h"
 #include "mozilla/ProfilerCounts.h"
+#include "mozilla/ThreadLocal.h"
 
+#include "GeckoProfiler.h"
+#include "prenv.h"
 #include "replace_malloc.h"
 
 #include <ctype.h>
@@ -35,7 +40,23 @@
 #  include <android/log.h>
 #endif
 
-static mozilla::UniquePtr<ProfilerCounterTotal> sCounter;
+// The counters start out as a nullptr, and then get initialized only once. They
+// are never destroyed, as it would cause race conditions for the memory hooks
+// that use the counters. This helps guard against potentially expensive
+// operations like using a mutex.
+//
+// In addition, this is a raw pointer and not a UniquePtr, as the counter
+// machinery will try and de-register itself from the profiler. This could
+// happen after the profiler and its PSMutex was already destroyed, resulting in
+// a crash.
+static ProfilerCounterTotal* sCounter;
+
+// The gBernoulli value starts out as a nullptr, and only gets initialized once.
+// It then lives for the entire lifetime of the process. It cannot be deleted
+// without additional multi-threaded protections, since if we deleted it during
+// profiler_stop then there could be a race between threads already in a
+// memory hook that might try to access the value after or during deletion.
+static mozilla::FastBernoulliTrial* gBernoulli;
 
 namespace mozilla {
 namespace profiler {
@@ -51,6 +72,116 @@ static size_t MallocSizeOf(const void* aPtr) {
   return gMallocTable.malloc_usable_size(const_cast<void*>(aPtr));
 }
 
+// The values for the Bernoulli trial are taken from DMD. According to DMD:
+//
+//   In testing, a probability of 0.003 resulted in ~25% of heap blocks getting
+//   a stack trace and ~80% of heap bytes getting a stack trace. (This is
+//   possible because big heap blocks are more likely to get a stack trace.)
+//
+//   The random number seeds are arbitrary and were obtained from random.org.
+//
+// However this value resulted in a lot of slowdown since the profiler stacks
+// are pretty heavy to collect. The value was lowered to 10% of the original to
+// 0.0003.
+static void EnsureBernoulliIsInstalled() {
+  if (!gBernoulli) {
+    // This is only installed once. See the gBernoulli definition for more
+    // information.
+    gBernoulli =
+        new FastBernoulliTrial(0.0003, 0x8e26eeee166bc8ca, 0x56820f304a9c9ae0);
+  }
+}
+
+//---------------------------------------------------------------------------
+// Per-thread blocking of intercepts
+//---------------------------------------------------------------------------
+
+// On MacOS, and Linux the first __thread/thread_local access calls malloc,
+// which leads to an infinite loop. So we use pthread-based TLS instead, which
+// somehow doesn't have this problem.
+#if !defined(XP_DARWIN) && !defined(XP_LINUX)
+#  define PROFILER_THREAD_LOCAL(T) MOZ_THREAD_LOCAL(T)
+#else
+#  define PROFILER_THREAD_LOCAL(T) \
+    ::mozilla::detail::ThreadLocal<T, ::mozilla::detail::ThreadLocalKeyStorage>
+#endif
+
+class ThreadIntercept {
+  // When set to true, malloc does not intercept additional allocations. This is
+  // needed because collecting stacks creates new allocations. When blocked,
+  // these allocations are then ignored by the memory hook.
+  static PROFILER_THREAD_LOCAL(bool) tlsIsBlocked;
+
+  // This is a quick flag to check and see if the allocations feature is enabled
+  // or disabled.
+  static mozilla::Atomic<bool, mozilla::Relaxed>
+      sAllocationsFeatureEnabled;
+
+  ThreadIntercept() = default;
+
+  // Only allow consumers to access this information if they run
+  // ThreadIntercept::MaybeGet and ask through the non-static version.
+  static bool IsBlocked_() {
+    return tlsIsBlocked.get() || profiler_could_be_locked_on_current_thread();
+  }
+
+ public:
+  static void Init() { tlsIsBlocked.infallibleInit(); }
+
+  // The ThreadIntercept object can only be created through this method, the
+  // constructor is private. This is so that we only check to see if the native
+  // allocations are turned on once, and not multiple times through the calls.
+  // The feature maybe be toggled between different stages of the memory hook.
+  static Maybe<ThreadIntercept> MaybeGet() {
+    if (sAllocationsFeatureEnabled && !ThreadIntercept::IsBlocked_()) {
+      // Only return thread intercepts when the native allocations feature is
+      // enabled and we aren't blocked.
+      return Some(ThreadIntercept());
+    }
+    return Nothing();
+  }
+
+  void Block() {
+    MOZ_ASSERT(!tlsIsBlocked.get());
+    tlsIsBlocked.set(true);
+  }
+
+  void Unblock() {
+    MOZ_ASSERT(tlsIsBlocked.get());
+    tlsIsBlocked.set(false);
+  }
+
+  bool IsBlocked() const { return ThreadIntercept::IsBlocked_(); }
+
+  static void EnableAllocationFeature() { sAllocationsFeatureEnabled = true; }
+
+  static void DisableAllocationFeature() { sAllocationsFeatureEnabled = false; }
+};
+
+PROFILER_THREAD_LOCAL(bool) ThreadIntercept::tlsIsBlocked;
+mozilla::Atomic<bool, mozilla::Relaxed>
+    ThreadIntercept::sAllocationsFeatureEnabled(false);
+
+// An object of this class must be created (on the stack) before running any
+// code that might allocate.
+class AutoBlockIntercepts {
+  ThreadIntercept& mThreadIntercept;
+
+ public:
+  // Disallow copy and assign.
+  AutoBlockIntercepts(const AutoBlockIntercepts&) = delete;
+  void operator=(const AutoBlockIntercepts&) = delete;
+
+  explicit AutoBlockIntercepts(ThreadIntercept& aThreadIntercept)
+      : mThreadIntercept(aThreadIntercept) {
+    mThreadIntercept.Block();
+  }
+  ~AutoBlockIntercepts() {
+    MOZ_ASSERT(mThreadIntercept.IsBlocked());
+    mThreadIntercept.Unblock();
+  }
+};
+
 //---------------------------------------------------------------------------
 // malloc/free callbacks
 //---------------------------------------------------------------------------
@@ -59,13 +190,34 @@ static void AllocCallback(void* aPtr, size_t aReqSize) {
   if (!aPtr) {
     return;
   }
+
+  // The first part of this function does not allocate.
   size_t actualSize = gMallocTable.malloc_usable_size(aPtr);
   if (actualSize > 0) {
-    // this never allocates
     sCounter->Add(actualSize);
   }
 
-  // XXX add optional stackwalk here
+  auto threadIntercept = ThreadIntercept::MaybeGet();
+  if (threadIntercept.isNothing()) {
+    // Either the native allocations feature is not turned on, or we  may be
+    // recursing into a memory hook, return. We'll still collect counter
+    // information about this allocation, but no stack.
+    return;
+  }
+
+  // The next part of the function requires allocations, so block the memory
+  // hooks from recursing on any new allocations coming in.
+  AutoBlockIntercepts block(threadIntercept.ref());
+
+  // Perform a bernoulli trial, which will return true or false based on its
+  // configured probability. It takes into account the byte size so that
+  // larger allocations are weighted heavier than smaller allocations.
+  MOZ_ASSERT(gBernoulli,
+             "gBernoulli must be properly installed for the memory hooks.");
+  if (gBernoulli->trial(actualSize)) {
+    profiler_add_native_allocation_marker((int64_t)actualSize);
+  }
+
   // We're ignoring aReqSize here
 }
 
@@ -74,10 +226,31 @@ static void FreeCallback(void* aPtr) {
     return;
   }
 
-  // this never allocates
-  sCounter->Add(-((int64_t)MallocSizeOf(aPtr)));
+  // The first part of this function does not allocate.
+  size_t unsignedSize = MallocSizeOf(aPtr);
+  int64_t signedSize = -((int64_t)unsignedSize);
+  sCounter->Add(signedSize);
 
-  // XXX add optional stackwalk here
+  auto threadIntercept = ThreadIntercept::MaybeGet();
+  if (threadIntercept.isNothing()) {
+    // Either the native allocations feature is not turned on, or we  may be
+    // recursing into a memory hook, return. We'll still collect counter
+    // information about this allocation, but no stack.
+    return;
+  }
+
+  // The next part of the function requires allocations, so block the memory
+  // hooks from recursing on any new allocations coming in.
+  AutoBlockIntercepts block(threadIntercept.ref());
+
+  // Perform a bernoulli trial, which will return true or false based on its
+  // configured probability. It takes into account the byte size so that
+  // larger allocations are weighted heavier than smaller allocations.
+  MOZ_ASSERT(gBernoulli,
+             "gBernoulli must be properly installed for the memory hooks.");
+  if (gBernoulli->trial(unsignedSize)) {
+    profiler_add_native_allocation_marker(signedSize);
+  }
 }
 
 }  // namespace profiler
@@ -194,16 +367,55 @@ namespace profiler {
 // Initialization
 //---------------------------------------------------------------------------
 
-void install_memory_counter(bool aInstall) {
-  if (aInstall) {
-    if (!sCounter) {
-      sCounter = MakeUnique<ProfilerCounterTotal>("malloc", "Memory",
-                                                  "Amount of allocated memory");
-    }
-    jemalloc_replace_dynamic(replace_init);
-  } else {
-    jemalloc_replace_dynamic(nullptr);
+void install_memory_hooks() {
+  if (!sCounter) {
+    sCounter = new ProfilerCounterTotal("malloc", "Memory",
+                                        "Amount of allocated memory");
+    // Also initialize the ThreadIntercept, even if native allocation tracking
+    // won't be turned on. This way the TLS will be initialized.
+    ThreadIntercept::Init();
   }
+  jemalloc_replace_dynamic(replace_init);
+}
+
+// Remove the hooks, but leave the sCounter machinery. Deleting the counter
+// would race with any existing memory hooks that are currently running. Rather
+// than adding overhead here of mutexes it's cheaper for the performance to just
+// leak these values.
+void remove_memory_hooks() { jemalloc_replace_dynamic(nullptr); }
+
+void enable_native_allocations() {
+  // The bloat log tracks allocations and de-allocations. This can conflict
+  // with the memory hook machinery, as the bloat log creates its own
+  // allocations. This means we can re-enter inside the bloat log machinery. At
+  // this time, the bloat log does not know about cannot handle the native
+  // allocation feature. For now just disable the feature.
+  //
+  // At the time of this writing, we hit this assertion:
+  // IsIdle(oldState) || IsRead(oldState) in Checker::StartReadOp()
+  //
+  //    #01: GetBloatEntry(char const*, unsigned int)
+  //    #02: NS_LogCtor
+  //    #03: profiler_get_backtrace()
+  //    #04: profiler_add_native_allocation_marker(long long)
+  //    #05: mozilla::profiler::AllocCallback(void*, unsigned long)
+  //    #06: replace_calloc(unsigned long, unsigned long)
+  //    #07: PLDHashTable::ChangeTable(int)
+  //    #08: PLDHashTable::Add(void const*, std::nothrow_t const&)
+  //    #09: nsBaseHashtable<nsDepCharHashKey, nsAutoPtr<BloatEntry>, ...
+  //    #10: GetBloatEntry(char const*, unsigned int)
+  //    #11: NS_LogCtor
+  //    #12: profiler_get_backtrace()
+  //    ...
+  if (!PR_GetEnv("XPCOM_MEM_BLOAT_LOG")) {
+    EnsureBernoulliIsInstalled();
+    ThreadIntercept::EnableAllocationFeature();
+  }
+}
+
+// This is safe to call even if native allocations hasn't been enabled.
+void disable_native_allocations() {
+  ThreadIntercept::DisableAllocationFeature();
 }
 
 }  // namespace profiler
diff --git a/tools/profiler/core/memory_hooks.h b/tools/profiler/core/memory_hooks.h
index fe870e93de..be5101a062 100644
--- a/tools/profiler/core/memory_hooks.h
+++ b/tools/profiler/core/memory_hooks.h
@@ -8,8 +8,13 @@
 #if defined(MOZ_REPLACE_MALLOC) && defined(MOZ_PROFILER_MEMORY)
 namespace mozilla {
 namespace profiler {
-void install_memory_counter(bool aInstall);
-}
+
+void install_memory_hooks();
+void remove_memory_hooks();
+void enable_native_allocations();
+void disable_native_allocations();
+
+}  // namespace profiler
 }  // namespace mozilla
 #endif
 
diff --git a/tools/profiler/core/platform-linux-android.cpp b/tools/profiler/core/platform-linux-android.cpp
index 05dd4d5dd2..5400e061e4 100644
--- a/tools/profiler/core/platform-linux-android.cpp
+++ b/tools/profiler/core/platform-linux-android.cpp
@@ -277,7 +277,7 @@ void Sampler::Disable(PSLockRef aLock) {
 template <typename Func>
 void Sampler::SuspendAndSampleAndResumeThread(
     PSLockRef aLock, const RegisteredThread& aRegisteredThread,
-    const Func& aProcessRegs) {
+    const TimeStamp& aNow, const Func& aProcessRegs) {
   // Only one sampler thread can be sampling at once.  So we expect to have
   // complete control over |sSigHandlerCoordinator|.
   MOZ_ASSERT(!sSigHandlerCoordinator);
@@ -332,7 +332,7 @@ void Sampler::SuspendAndSampleAndResumeThread(
   // Extract the current register values.
   Registers regs;
   PopulateRegsFromContext(regs, &sSigHandlerCoordinator->mUContext);
-  aProcessRegs(regs);
+  aProcessRegs(regs, aNow);
 
   //----------------------------------------------------------------//
   // Resume the target thread.
@@ -376,7 +376,7 @@ static void* ThreadEntry(void* aArg) {
 
 SamplerThread::SamplerThread(PSLockRef aLock, uint32_t aActivityGeneration,
                              double aIntervalMilliseconds)
-    : Sampler(aLock),
+    : mSampler(aLock),
       mActivityGeneration(aActivityGeneration),
       mIntervalMicroseconds(
           std::max(1, int(floor(aIntervalMilliseconds * 1000 + 0.5)))) {
@@ -440,7 +440,7 @@ void SamplerThread::Stop(PSLockRef aLock) {
   // though this SamplerThread is still alive, because the next time the main
   // loop of Run() iterates it won't get past the mActivityGeneration check,
   // and so won't send any signals.
-  Sampler::Disable(aLock);
+  mSampler.Disable(aLock);
 }
 
 // END SamplerThread target specifics
diff --git a/tools/profiler/core/platform-macos.cpp b/tools/profiler/core/platform-macos.cpp
index 36c41f7283..3c3b12323c 100644
--- a/tools/profiler/core/platform-macos.cpp
+++ b/tools/profiler/core/platform-macos.cpp
@@ -74,7 +74,7 @@ void Sampler::Disable(PSLockRef aLock) {}
 template <typename Func>
 void Sampler::SuspendAndSampleAndResumeThread(
     PSLockRef aLock, const RegisteredThread& aRegisteredThread,
-    const Func& aProcessRegs) {
+    const TimeStamp& aNow, const Func& aProcessRegs) {
   thread_act_t samplee_thread =
       aRegisteredThread.GetPlatformData()->ProfiledThread();
 
@@ -117,7 +117,7 @@ void Sampler::SuspendAndSampleAndResumeThread(
     regs.mFP = reinterpret_cast<Address>(state.REGISTER_FIELD(bp));
     regs.mLR = 0;
 
-    aProcessRegs(regs);
+    aProcessRegs(regs, aNow);
   }
 
 #undef REGISTER_FIELD
@@ -146,7 +146,7 @@ static void* ThreadEntry(void* aArg) {
 
 SamplerThread::SamplerThread(PSLockRef aLock, uint32_t aActivityGeneration,
                              double aIntervalMilliseconds)
-    : Sampler(aLock),
+    : mSampler(aLock),
       mActivityGeneration(aActivityGeneration),
       mIntervalMicroseconds(
           std::max(1, int(floor(aIntervalMilliseconds * 1000 + 0.5)))),
@@ -167,7 +167,7 @@ void SamplerThread::SleepMicro(uint32_t aMicroseconds) {
   // case where the usleep call is interrupted by a signal.
 }
 
-void SamplerThread::Stop(PSLockRef aLock) { Sampler::Disable(aLock); }
+void SamplerThread::Stop(PSLockRef aLock) { mSampler.Disable(aLock); }
 
 // END SamplerThread target specifics
 ////////////////////////////////////////////////////////////////////////
diff --git a/tools/profiler/core/platform-win32.cpp b/tools/profiler/core/platform-win32.cpp
index 3e5421eb98..478cf683db 100644
--- a/tools/profiler/core/platform-win32.cpp
+++ b/tools/profiler/core/platform-win32.cpp
@@ -124,7 +124,7 @@ void Sampler::Disable(PSLockRef aLock) {}
 template <typename Func>
 void Sampler::SuspendAndSampleAndResumeThread(
     PSLockRef aLock, const RegisteredThread& aRegisteredThread,
-    const Func& aProcessRegs) {
+    const TimeStamp& aNow, const Func& aProcessRegs) {
   HANDLE profiled_thread =
       aRegisteredThread.GetPlatformData()->ProfiledThread();
   if (profiled_thread == nullptr) {
@@ -170,7 +170,7 @@ void Sampler::SuspendAndSampleAndResumeThread(
 
   Registers regs;
   PopulateRegsFromContext(regs, &context);
-  aProcessRegs(regs);
+  aProcessRegs(regs, aNow);
 
   //----------------------------------------------------------------//
   // Resume the target thread.
@@ -196,7 +196,7 @@ static unsigned int __stdcall ThreadEntry(void* aArg) {
 
 SamplerThread::SamplerThread(PSLockRef aLock, uint32_t aActivityGeneration,
                              double aIntervalMilliseconds)
-    : Sampler(aLock),
+    : mSampler(aLock),
       mActivityGeneration(aActivityGeneration),
       mIntervalMicroseconds(
           std::max(1, int(floor(aIntervalMilliseconds * 1000 + 0.5)))) {
@@ -235,7 +235,7 @@ void SamplerThread::SleepMicro(uint32_t aMicroseconds) {
   if (mIntervalMicroseconds >= 1000) {
     ::Sleep(std::max(1u, aMicroseconds / 1000));
   } else {
-    TimeStamp start = TimeStamp::Now();
+    TimeStamp start = TimeStamp::NowUnfuzzed();
     TimeStamp end = start + TimeDuration::FromMicroseconds(aMicroseconds);
 
     // First, sleep for as many whole milliseconds as possible.
@@ -244,7 +244,7 @@ void SamplerThread::SleepMicro(uint32_t aMicroseconds) {
     }
 
     // Then, spin until enough time has passed.
-    while (TimeStamp::Now() < end) {
+    while (TimeStamp::NowUnfuzzed() < end) {
       YieldProcessor();
     }
   }
@@ -263,7 +263,7 @@ void SamplerThread::Stop(PSLockRef aLock) {
     ::timeEndPeriod(mIntervalMicroseconds / 1000);
   }
 
-  Sampler::Disable(aLock);
+  mSampler.Disable(aLock);
 }
 
 // END SamplerThread target specifics
diff --git a/tools/profiler/core/platform.cpp b/tools/profiler/core/platform.cpp
index 9173888e44..1fe07ad940 100644
--- a/tools/profiler/core/platform.cpp
+++ b/tools/profiler/core/platform.cpp
@@ -32,7 +32,7 @@
 #include "ProfiledThreadData.h"
 #include "ProfilerBacktrace.h"
 #include "ProfileBuffer.h"
-//#include "ProfilerIOInterposeObserver.h"
+#include "ProfilerIOInterposeObserver.h"
 #include "ProfilerMarkerPayload.h"
 #include "ProfilerParent.h"
 #include "RegisteredThread.h"
@@ -210,9 +210,6 @@ static uint32_t AvailableFeatures() {
 #endif
 #if !defined(MOZ_TASK_TRACER)
   ProfilerFeature::ClearTaskTracer(features);
-#endif
-#if !(defined(MOZ_REPLACE_MALLOC) && defined(MOZ_PROFILER_MEMORY))
-  ProfilerFeature::ClearMemory(features);
 #endif
   if (!JS::TraceLoggerSupported()) {
     ProfilerFeature::ClearJSTracer(features);
@@ -224,8 +221,7 @@ static uint32_t AvailableFeatures() {
 // Default features common to all contexts (even if not available).
 static uint32_t DefaultFeatures() {
   return ProfilerFeature::Java | ProfilerFeature::JS | ProfilerFeature::Leaf |
-         ProfilerFeature::StackWalk | ProfilerFeature::Threads |
-         ProfilerFeature::Responsiveness;
+         ProfilerFeature::StackWalk | ProfilerFeature::Threads;
 }
 
 // Extra default features when MOZ_PROFILER_STARTUP is set (even if not
@@ -233,12 +229,67 @@ static uint32_t DefaultFeatures() {
 static uint32_t StartupExtraDefaultFeatures() {
   // Enable mainthreadio by default for startup profiles as startup is heavy on
   // I/O operations, and main thread I/O is really important to see there.
-  return ProfilerFeature::MainThreadIO | ProfilerFeature::Memory;
+  return ProfilerFeature::MainThreadIO;
 }
 
-class PSMutex : public StaticMutex {};
+// The class is a thin shell around mozglue PlatformMutex. It does not preserve
+// behavior in JS record/replay. It provides a mechanism to determine if it is
+// locked or not in order for memory hooks to avoid re-entering the profiler
+// locked state.
+class PSMutex : private ::mozilla::detail::MutexImpl {
+ public:
+  PSMutex() : ::mozilla::detail::MutexImpl(), mIsLocked(false) {}
+  void Lock() {
+    ::mozilla::detail::MutexImpl::lock();
+    // Set mIsLocked to true, don't trust this value too much!
+    mIsLocked = true;
+  }
 
-typedef BaseAutoLock<PSMutex&> PSAutoLock;
+  void Unlock() {
+    mIsLocked = false;
+    ::mozilla::detail::MutexImpl::unlock();
+  }
+
+  // Warning! Do not mis-use this method.
+  //
+  // When the native allocations feature is turned on, memory hooks run on
+  // every single allocation. For a subset of these allocations, the stack
+  // gets sampled by running profiler_get_backtrace(), which locks the PSMutex.
+  //
+  // An issue arises when allocating while the profiler is locked FOR THE
+  // CURRENT THREAD. In this situation, if profiler_get_backtrace() were to be
+  // run, it would try to re-acquire this lock and deadlock. In order to guard
+  // against this deadlock, this method provides a check to see if the mutex is
+  // already locked.
+  //
+  // This method is not perfect, and will return many false positives when the
+  // mutex is modified by ANOTHER THREAD. In this case we will fail to collect a
+  // stack when it is valid to do so. While not a perfect solution, it is an
+  // acceptable limitation in order to have full-featured stack information.
+  //
+  // However, despite these false positives from another thread, we will not get
+  // false positive or false negatives from THE CURRENT THREAD, which is the
+  // only situation where we will get a deadlock.
+  //
+  // This non-perfect, but functional solution could be worked around if the
+  // profile_get_backtrace() mechanism were to remove all allocations.
+  // See Bug 1578792 for tracking this work.
+  bool CouldBeLockedOnCurrentThread() const { return mIsLocked; }
+
+  // This value protects against re-entering in the current thread from a
+  // a memory hook when the profiler state is locked BY THE CURRENT THREAD.
+  Atomic<bool, MemoryOrdering::Relaxed> mIsLocked;
+};
+
+// RAII class to lock the profiler mutex.
+class MOZ_RAII PSAutoLock {
+ public:
+  explicit PSAutoLock(PSMutex& aMutex) : mMutex(aMutex) { mMutex.Lock(); }
+  ~PSAutoLock() { mMutex.Unlock(); }
+
+ private:
+  PSMutex& mMutex;
+};
 
 // Only functions that take a PSLockRef arg can access CorePS's and ActivePS's
 // fields.
@@ -280,7 +331,12 @@ typedef const PSAutoLock& PSLockRef;
 class CorePS {
  private:
   CorePS()
-      : mProcessStartTime(TimeStamp::ProcessCreation())
+      : mProcessStartTime(TimeStamp::ProcessCreation()),
+        // This needs its own mutex, because it is used concurrently from
+        // functions guarded by gPSMutex as well as others without safety (e.g.,
+        // profiler_add_marker). It is *not* used inside the critical section of
+        // the sampler, because mutexes cannot be used there.
+        mCoreBlocksRingBuffer(BlocksRingBuffer::ThreadSafety::WithMutex)
 #ifdef USE_LUL_STACKWALK
         ,
         mLul(nullptr)
@@ -333,6 +389,9 @@ class CorePS {
   // No PSLockRef is needed for this field because it's immutable.
   PS_GET_LOCKLESS(TimeStamp, ProcessStartTime)
 
+  // No PSLockRef is needed for this field because it's thread-safe.
+  PS_GET_LOCKLESS(BlocksRingBuffer&, CoreBlocksRingBuffer)
+
   PS_GET(const Vector<UniquePtr<RegisteredThread>>&, RegisteredThreads)
 
   static void AppendRegisteredThread(
@@ -417,6 +476,17 @@ class CorePS {
   // The time that the process started.
   const TimeStamp mProcessStartTime;
 
+  // The thread-safe blocks-oriented ring buffer into which all profiling data
+  // is recorded.
+  // ActivePS controls the lifetime of the underlying contents buffer: When
+  // ActivePS does not exist, mCoreBlocksRingBuffer is empty and rejects all
+  // reads&writes; see ActivePS for further details.
+  // Note: This needs to live here outside of ActivePS, because some producers
+  // are indirectly controlled (e.g., by atomic flags) and therefore may still
+  // attempt to write some data shortly after ActivePS has shutdown and deleted
+  // the underlying buffer in memory.
+  BlocksRingBuffer mCoreBlocksRingBuffer;
+
   // Info on all the registered threads.
   // ThreadIds in mRegisteredThreads are unique.
   Vector<UniquePtr<RegisteredThread>> mRegisteredThreads;
@@ -471,7 +541,7 @@ class ActivePS {
     return aFeatures;
   }
 
-  ActivePS(PSLockRef aLock, uint32_t aCapacity, double aInterval,
+  ActivePS(PSLockRef aLock, PowerOfTwo32 aCapacity, double aInterval,
            uint32_t aFeatures, const char** aFilters, uint32_t aFilterCount,
            const Maybe<double>& aDuration)
       : mGeneration(sNextGeneration++),
@@ -479,17 +549,16 @@ class ActivePS {
         mDuration(aDuration),
         mInterval(aInterval),
         mFeatures(AdjustFeatures(aFeatures, aFilterCount)),
-        mBuffer(MakeUnique<ProfileBuffer>(aCapacity))
+        // 8 bytes per entry.
+        mProfileBuffer(CorePS::CoreBlocksRingBuffer(),
+                       PowerOfTwo32(aCapacity.Value() * 8)),
         // The new sampler thread doesn't start sampling immediately because the
         // main loop within Run() is blocked until this function's caller
         // unlocks gPSMutex.
-        ,
-        mSamplerThread(NewSamplerThread(aLock, mGeneration, aInterval))
-        /*mInterposeObserver(ProfilerFeature::HasMainThreadIO(aFeatures)
+        mSamplerThread(NewSamplerThread(aLock, mGeneration, aInterval)),
+        mInterposeObserver(ProfilerFeature::HasMainThreadIO(aFeatures)
                                ? new ProfilerIOInterposeObserver()
-                               : nullptr)*/
-#undef HAS_FEATURE
-        ,
+                               : nullptr),
         mIsPaused(false)
 #if defined(GP_OS_linux)
         ,
@@ -502,7 +571,7 @@ class ActivePS {
       mFilters[i] = aFilters[i];
     }
 
-/*#if !defined(RELEASE_OR_BETA)
+#if !defined(RELEASE_OR_BETA)
     if (mInterposeObserver) {
       // We need to register the observer on the main thread, because we want
       // to observe IO that happens on the main thread.
@@ -520,11 +589,11 @@ class ActivePS {
             }));
       }
     }
-#endif*/
+#endif
   }
 
   ~ActivePS() {
-/*#if !defined(RELEASE_OR_BETA)
+#if !defined(RELEASE_OR_BETA)
     if (mInterposeObserver) {
       // We need to unregister the observer on the main thread, because that's
       // where we've registered it.
@@ -539,7 +608,7 @@ class ActivePS {
             }));
       }
     }
-#endif*/
+#endif
   }
 
   bool ThreadSelected(const char* aThreadName) {
@@ -574,7 +643,7 @@ class ActivePS {
   }
 
  public:
-  static void Create(PSLockRef aLock, uint32_t aCapacity, double aInterval,
+  static void Create(PSLockRef aLock, PowerOfTwo32 aCapacity, double aInterval,
                      uint32_t aFeatures, const char** aFilters,
                      uint32_t aFilterCount, const Maybe<double>& aDuration) {
     sInstance = new ActivePS(aLock, aCapacity, aInterval, aFeatures, aFilters,
@@ -591,7 +660,7 @@ class ActivePS {
 
   static bool Exists(PSLockRef) { return !!sInstance; }
 
-  static bool Equals(PSLockRef, uint32_t aCapacity,
+  static bool Equals(PSLockRef, PowerOfTwo32 aCapacity,
                      const Maybe<double>& aDuration, double aInterval,
                      uint32_t aFeatures, const char** aFilters,
                      uint32_t aFilterCount) {
@@ -614,7 +683,7 @@ class ActivePS {
   static size_t SizeOf(PSLockRef, MallocSizeOf aMallocSizeOf) {
     size_t n = aMallocSizeOf(sInstance);
 
-    n += sInstance->mBuffer->SizeOfIncludingThis(aMallocSizeOf);
+    n += sInstance->mProfileBuffer.SizeOfExcludingThis(aMallocSizeOf);
 
     // Measurement of the following members may be added later if DMD finds it
     // is worthwhile:
@@ -634,7 +703,7 @@ class ActivePS {
 
   PS_GET(uint32_t, Generation)
 
-  PS_GET(uint32_t, Capacity)
+  PS_GET(PowerOfTwo32, Capacity)
 
   PS_GET(Maybe<double>, Duration)
 
@@ -655,9 +724,6 @@ class ActivePS {
     uint32_t Flags = 0;
     Flags |=
         FeatureJS(aLock) ? uint32_t(JSInstrumentationFlags::StackSampling) : 0;
-    Flags |= FeatureTrackOptimizations(aLock)
-                 ? uint32_t(JSInstrumentationFlags::TrackOptimizations)
-                 : 0;
     Flags |= FeatureJSTracer(aLock)
                  ? uint32_t(JSInstrumentationFlags::TraceLogging)
                  : 0;
@@ -669,7 +735,7 @@ class ActivePS {
 
   PS_GET(const Vector<std::string>&, Filters)
 
-  static ProfileBuffer& Buffer(PSLockRef) { return *sInstance->mBuffer.get(); }
+  static ProfileBuffer& Buffer(PSLockRef) { return sInstance->mProfileBuffer; }
 
   static const Vector<LiveProfiledThreadData>& LiveProfiledThreads(PSLockRef) {
     return sInstance->mLiveProfiledThreads;
@@ -684,26 +750,26 @@ class ActivePS {
   // The returned array is sorted by thread register time.
   // Do not hold on to the return value across thread registration or profiler
   // restarts.
-  static Vector<Pair<RegisteredThread*, ProfiledThreadData*>> ProfiledThreads(
-      PSLockRef) {
-    Vector<Pair<RegisteredThread*, ProfiledThreadData*>> array;
+  static Vector<std::pair<RegisteredThread*, ProfiledThreadData*>>
+  ProfiledThreads(PSLockRef) {
+    Vector<std::pair<RegisteredThread*, ProfiledThreadData*>> array;
     MOZ_RELEASE_ASSERT(
         array.initCapacity(sInstance->mLiveProfiledThreads.length() +
                            sInstance->mDeadProfiledThreads.length()));
     for (auto& t : sInstance->mLiveProfiledThreads) {
       MOZ_RELEASE_ASSERT(array.append(
-          MakePair(t.mRegisteredThread, t.mProfiledThreadData.get())));
+          std::make_pair(t.mRegisteredThread, t.mProfiledThreadData.get())));
     }
     for (auto& t : sInstance->mDeadProfiledThreads) {
       MOZ_RELEASE_ASSERT(
-          array.append(MakePair((RegisteredThread*)nullptr, t.get())));
+          array.append(std::make_pair((RegisteredThread*)nullptr, t.get())));
     }
 
     std::sort(array.begin(), array.end(),
-              [](const Pair<RegisteredThread*, ProfiledThreadData*>& a,
-                 const Pair<RegisteredThread*, ProfiledThreadData*>& b) {
-                return a.second()->Info()->RegisterTime() <
-                       b.second()->Info()->RegisterTime();
+              [](const std::pair<RegisteredThread*, ProfiledThreadData*>& a,
+                 const std::pair<RegisteredThread*, ProfiledThreadData*>& b) {
+                return a.second->Info()->RegisterTime() <
+                       b.second->Info()->RegisterTime();
               });
     return array;
   }
@@ -757,7 +823,7 @@ class ActivePS {
       LiveProfiledThreadData& thread = sInstance->mLiveProfiledThreads[i];
       if (thread.mRegisteredThread == aRegisteredThread) {
         thread.mProfiledThreadData->NotifyUnregistered(
-            sInstance->mBuffer->mRangeEnd);
+            sInstance->mProfileBuffer.BufferRangeEnd());
         MOZ_RELEASE_ASSERT(sInstance->mDeadProfiledThreads.append(
             std::move(thread.mProfiledThreadData)));
         sInstance->mLiveProfiledThreads.erase(
@@ -774,7 +840,7 @@ class ActivePS {
 #endif
 
   static void DiscardExpiredDeadProfiledThreads(PSLockRef) {
-    uint64_t bufferRangeStart = sInstance->mBuffer->mRangeStart;
+    uint64_t bufferRangeStart = sInstance->mProfileBuffer.BufferRangeStart();
     // Discard any dead threads that were unregistered before bufferRangeStart.
     sInstance->mDeadProfiledThreads.eraseIf(
         [bufferRangeStart](
@@ -793,7 +859,7 @@ class ActivePS {
     for (size_t i = 0; i < registeredPages.length(); i++) {
       RefPtr<PageInformation>& page = registeredPages[i];
       if (page->DocShellId().Equals(aRegisteredDocShellId)) {
-        page->NotifyUnregistered(sInstance->mBuffer->mRangeEnd);
+        page->NotifyUnregistered(sInstance->mProfileBuffer.BufferRangeEnd());
         MOZ_RELEASE_ASSERT(
             sInstance->mDeadProfiledPages.append(std::move(page)));
         registeredPages.erase(&registeredPages[i--]);
@@ -802,7 +868,7 @@ class ActivePS {
   }
 
   static void DiscardExpiredPages(PSLockRef) {
-    uint64_t bufferRangeStart = sInstance->mBuffer->mRangeStart;
+    uint64_t bufferRangeStart = sInstance->mProfileBuffer.BufferRangeStart();
     // Discard any dead pages that were unregistered before
     // bufferRangeStart.
     sInstance->mDeadProfiledPages.eraseIf(
@@ -819,7 +885,7 @@ class ActivePS {
     sInstance->mDeadProfiledPages.clear();
   }
 
-/*#if !defined(RELEASE_OR_BETA)
+#if !defined(RELEASE_OR_BETA)
   static void UnregisterIOInterposer(PSLockRef) {
     if (!sInstance->mInterposeObserver) {
       return;
@@ -848,13 +914,16 @@ class ActivePS {
     IOInterposer::Register(IOInterposeObserver::OpAll,
                            sInstance->mInterposeObserver);
   }
-#endif*/
+#endif
 
   static void ClearExpiredExitProfiles(PSLockRef) {
-    uint64_t bufferRangeStart = sInstance->mBuffer->mRangeStart;
+    uint64_t bufferRangeStart = sInstance->mProfileBuffer.BufferRangeStart();
     // Discard exit profiles that were gathered before our buffer RangeStart.
 #ifdef MOZ_BASE_PROFILER
-    if (bufferRangeStart != 0 && sInstance->mBaseProfileThreads) {
+    // The buffer range starts at 1 (the first valid entry, 0 is reserved as
+    // null marker). So if it now starts *after* 1, it means we have started to
+    // overwrite our oldest data, and we should get rid of Base profiles if any.
+    if (bufferRangeStart > 1 && sInstance->mBaseProfileThreads) {
       sInstance->mBaseProfileThreads.reset();
     }
 #endif
@@ -881,7 +950,7 @@ class ActivePS {
     ClearExpiredExitProfiles(aLock);
 
     MOZ_RELEASE_ASSERT(sInstance->mExitProfiles.append(
-        ExitProfile{aExitProfile, sInstance->mBuffer->mRangeEnd}));
+        ExitProfile{aExitProfile, sInstance->mProfileBuffer.BufferRangeEnd()}));
   }
 
   static Vector<nsCString> MoveExitProfiles(PSLockRef aLock) {
@@ -921,10 +990,10 @@ class ActivePS {
   const uint32_t mGeneration;
   static uint32_t sNextGeneration;
 
-  // The maximum number of entries in mBuffer.
-  const uint32_t mCapacity;
+  // The maximum number of entries in mProfileBuffer.
+  const PowerOfTwo32 mCapacity;
 
-  // The maximum duration of entries in mBuffer, in seconds.
+  // The maximum duration of entries in mProfileBuffer, in seconds.
   const Maybe<double> mDuration;
 
   // The interval between samples, measured in milliseconds.
@@ -936,9 +1005,8 @@ class ActivePS {
   // Substrings of names of threads we want to profile.
   Vector<std::string> mFilters;
 
-  // The buffer into which all samples are recorded. Always non-null. Always
-  // used in conjunction with CorePS::m{Live,Dead}Threads.
-  const UniquePtr<ProfileBuffer> mBuffer;
+  // The buffer into which all samples are recorded.
+  ProfileBuffer mProfileBuffer;
 
   // ProfiledThreadData objects for any threads that were profiled at any point
   // during this run of the profiler:
@@ -960,7 +1028,7 @@ class ActivePS {
   SamplerThread* const mSamplerThread;
 
   // The interposer that records main thread I/O.
-  //RefPtr<ProfilerIOInterposeObserver> mInterposeObserver;
+  RefPtr<ProfilerIOInterposeObserver> mInterposeObserver;
 
   // Is the profiler paused?
   bool mIsPaused;
@@ -1080,8 +1148,8 @@ class Registers {
   void Clear() { memset(this, 0, sizeof(*this)); }
 
   // These fields are filled in by
-  // SamplerThread::SuspendAndSampleAndResumeThread() for periodic and
-  // backtrace samples, and by SyncPopulate() for synchronous samples.
+  // Sampler::SuspendAndSampleAndResumeThread() for periodic and backtrace
+  // samples, and by SyncPopulate() for synchronous samples.
   Address mPC;  // Instruction pointer.
   Address mSP;  // Stack pointer.
   Address mFP;  // Frame pointer.
@@ -1675,24 +1743,17 @@ static void DoNativeBacktrace(PSLockRef aLock,
 // ProfileBuffer::StreamSamplesToJSON.
 static inline void DoSharedSample(PSLockRef aLock, bool aIsSynchronous,
                                   RegisteredThread& aRegisteredThread,
-                                  const TimeStamp& aNow, const Registers& aRegs,
-                                  Maybe<uint64_t>* aLastSample,
+                                  const Registers& aRegs, uint64_t aSamplePos,
                                   ProfileBuffer& aBuffer) {
   // WARNING: this function runs within the profiler's "critical section".
 
+  MOZ_ASSERT(!aBuffer.IsThreadSafe(),
+             "Mutexes cannot be used inside this critical section");
+
   MOZ_RELEASE_ASSERT(ActivePS::Exists(aLock));
 
-  uint64_t samplePos =
-      aBuffer.AddThreadIdEntry(aRegisteredThread.Info()->ThreadId());
-  if (aLastSample) {
-    *aLastSample = Some(samplePos);
-  }
-
-  TimeDuration delta = aNow - CorePS::ProcessStartTime();
-  aBuffer.AddEntry(ProfileBufferEntry::Time(delta.ToMilliseconds()));
-
   ProfileBufferCollector collector(aBuffer, ActivePS::Features(aLock),
-                                   samplePos);
+                                   aSamplePos);
   NativeStack nativeStack;
 #if defined(HAVE_NATIVE_UNWIND)
   if (ActivePS::FeatureStackWalk(aLock)) {
@@ -1719,36 +1780,29 @@ static void DoSyncSample(PSLockRef aLock, RegisteredThread& aRegisteredThread,
                          ProfileBuffer& aBuffer) {
   // WARNING: this function runs within the profiler's "critical section".
 
-  DoSharedSample(aLock, /* aIsSynchronous = */ true, aRegisteredThread, aNow,
-                 aRegs, /* aLastSample = */ nullptr, aBuffer);
+  uint64_t samplePos =
+      aBuffer.AddThreadIdEntry(aRegisteredThread.Info()->ThreadId());
+
+  TimeDuration delta = aNow - CorePS::ProcessStartTime();
+  aBuffer.AddEntry(ProfileBufferEntry::Time(delta.ToMilliseconds()));
+
+  DoSharedSample(aLock, /* aIsSynchronous = */ true, aRegisteredThread, aRegs,
+                 samplePos, aBuffer);
 }
 
 // Writes the components of a periodic sample to ActivePS's ProfileBuffer.
-static void DoPeriodicSample(PSLockRef aLock,
-                             RegisteredThread& aRegisteredThread,
-                             ProfiledThreadData& aProfiledThreadData,
-                             const TimeStamp& aNow, const Registers& aRegs) {
+// The ThreadId entry is already written in the main ProfileBuffer, its location
+// is `aSamplePos`, we can write the rest to `aBuffer` (which may be different).
+static inline void DoPeriodicSample(PSLockRef aLock,
+                                    RegisteredThread& aRegisteredThread,
+                                    ProfiledThreadData& aProfiledThreadData,
+                                    const TimeStamp& aNow,
+                                    const Registers& aRegs, uint64_t aSamplePos,
+                                    ProfileBuffer& aBuffer) {
   // WARNING: this function runs within the profiler's "critical section".
 
-  ProfileBuffer& buffer = ActivePS::Buffer(aLock);
-
-  DoSharedSample(aLock, /* aIsSynchronous = */ false, aRegisteredThread, aNow,
-                 aRegs, &aProfiledThreadData.LastSample(), buffer);
-
-  ProfilerMarkerLinkedList* pendingMarkersList =
-      aRegisteredThread.RacyRegisteredThread().GetPendingMarkers();
-  while (pendingMarkersList && pendingMarkersList->peek()) {
-    ProfilerMarker* marker = pendingMarkersList->popHead();
-    buffer.AddStoredMarker(marker);
-    buffer.AddEntry(ProfileBufferEntry::Marker(marker));
-  }
-
-  ThreadResponsiveness* resp = aProfiledThreadData.GetThreadResponsiveness();
-  if (resp && resp->HasData()) {
-    double delta = resp->GetUnresponsiveDuration(
-        (aNow - CorePS::ProcessStartTime()).ToMilliseconds());
-    buffer.AddEntry(ProfileBufferEntry::Responsiveness(delta));
-  }
+  DoSharedSample(aLock, /* aIsSynchronous = */ false, aRegisteredThread, aRegs,
+                 aSamplePos, aBuffer);
 }
 
 // END sampling/unwinding code
@@ -1824,10 +1878,10 @@ static void StreamTaskTracer(PSLockRef aLock, SpliceableJSONWriter& aWriter) {
   aWriter.StartArrayProperty("threads");
   {
     ActivePS::DiscardExpiredDeadProfiledThreads(aLock);
-    Vector<Pair<RegisteredThread*, ProfiledThreadData*>> threads =
+    Vector<std::pair<RegisteredThread*, ProfiledThreadData*>> threads =
         ActivePS::ProfiledThreads(aLock);
     for (auto& thread : threads) {
-      RefPtr<ThreadInfo> info = thread.second()->Info();
+      RefPtr<ThreadInfo> info = thread.second->Info();
       StreamNameAndThreadId(aWriter, info->Name(), info->ThreadId());
     }
   }
@@ -1839,14 +1893,35 @@ static void StreamTaskTracer(PSLockRef aLock, SpliceableJSONWriter& aWriter) {
 }
 
 static void StreamCategories(SpliceableJSONWriter& aWriter) {
-  // Same order as ProfilingCategory.
+  // Same order as ProfilingCategory. Format:
+  // [
+  //   {
+  //     name: "Idle",
+  //     color: "transparent",
+  //     subcategories: ["Other"],
+  //   },
+  //   {
+  //     name: "Other",
+  //     color: "grey",
+  //     subcategories: [
+  //       "JSM loading",
+  //       "Subprocess launching",
+  //       "DLL loading"
+  //     ]
+  //   },
+  //   ...
+  // ]
 
 #define CATEGORY_JSON_BEGIN_CATEGORY(name, labelAsString, color) \
   aWriter.Start();                                               \
   aWriter.StringProperty("name", labelAsString);                 \
-  aWriter.StringProperty("color", color);
-#define CATEGORY_JSON_SUBCATEGORY(category, name, labelAsString)
-#define CATEGORY_JSON_END_CATEGORY aWriter.EndObject();
+  aWriter.StringProperty("color", color);                        \
+  aWriter.StartArrayProperty("subcategories");
+#define CATEGORY_JSON_SUBCATEGORY(supercategory, name, labelAsString) \
+  aWriter.StringElement(labelAsString);
+#define CATEGORY_JSON_END_CATEGORY \
+  aWriter.EndArray();              \
+  aWriter.EndObject();
 
   PROFILING_CATEGORY_LIST(CATEGORY_JSON_BEGIN_CATEGORY,
                           CATEGORY_JSON_SUBCATEGORY, CATEGORY_JSON_END_CATEGORY)
@@ -1861,12 +1936,12 @@ static void StreamMetaJSCustomObject(PSLockRef aLock,
                                      bool aIsShuttingDown) {
   MOZ_RELEASE_ASSERT(CorePS::Exists() && ActivePS::Exists(aLock));
 
-  aWriter.IntProperty("version", 15);
+  aWriter.IntProperty("version", 16);
 
   // The "startTime" field holds the number of milliseconds since midnight
   // January 1, 1970 GMT. This grotty code computes (Now - (Now -
   // ProcessStartTime)) to convert CorePS::ProcessStartTime() into that form.
-  TimeDuration delta = TimeStamp::Now() - CorePS::ProcessStartTime();
+  TimeDuration delta = TimeStamp::NowUnfuzzed() - CorePS::ProcessStartTime();
   aWriter.DoubleProperty(
       "startTime",
       static_cast<double>(PR_Now() / 1000.0 - delta.ToMilliseconds()));
@@ -2024,11 +2099,13 @@ static void StreamPages(PSLockRef aLock, SpliceableJSONWriter& aWriter) {
 }
 
 #if defined(GP_OS_android)
-static UniquePtr<ProfileBuffer> CollectJavaThreadProfileData() {
+static UniquePtr<ProfileBuffer> CollectJavaThreadProfileData(
+    BlocksRingBuffer& bufferManager) {
   // locked_profiler_start uses sample count is 1000 for Java thread.
   // This entry size is enough now, but we might have to estimate it
   // if we can customize it
-  auto buffer = MakeUnique<ProfileBuffer>(1000 * 1000);
+  auto buffer = MakeUnique<ProfileBuffer>(bufferManager,
+                                          MakePowerOfTwo32<8 * 1024 * 1024>());
 
   int sampleId = 0;
   while (true) {
@@ -2072,17 +2149,35 @@ static UniquePtr<ProfileBuffer> CollectJavaThreadProfileData() {
 }
 #endif
 
+UniquePtr<ProfilerCodeAddressService>
+profiler_code_address_service_for_presymbolication() {
+  static const bool preSymbolicate = []() {
+    const char* symbolicate = getenv("MOZ_PROFILER_SYMBOLICATE");
+    return symbolicate && symbolicate[0] != '\0';
+  }();
+  return preSymbolicate ? MakeUnique<ProfilerCodeAddressService>() : nullptr;
+}
+
 static void locked_profiler_stream_json_for_this_process(
     PSLockRef aLock, SpliceableJSONWriter& aWriter, double aSinceTime,
-    bool aIsShuttingDown) {
+    bool aIsShuttingDown, ProfilerCodeAddressService* aService) {
   LOG("locked_profiler_stream_json_for_this_process");
 
   MOZ_RELEASE_ASSERT(CorePS::Exists() && ActivePS::Exists(aLock));
 
-  double collectionStart = profiler_time();
+  AUTO_PROFILER_STATS(locked_profiler_stream_json_for_this_process);
+
+  const double collectionStartMs = profiler_time();
 
   ProfileBuffer& buffer = ActivePS::Buffer(aLock);
 
+  // If there is a set "Window length", discard older data.
+  Maybe<double> durationS = ActivePS::Duration(aLock);
+  if (durationS.isSome()) {
+    const double durationStartMs = collectionStartMs - *durationS * 1000;
+    buffer.DiscardSamplesBeforeTime(durationStartMs);
+  }
+
   // Put shared library info
   aWriter.StartArrayProperty("libs");
   AppendSharedLibraries(aWriter);
@@ -2101,7 +2196,6 @@ static void locked_profiler_stream_json_for_this_process(
   buffer.StreamProfilerOverheadToJSON(aWriter, CorePS::ProcessStartTime(),
                                       aSinceTime);
   buffer.StreamCountersToJSON(aWriter, CorePS::ProcessStartTime(), aSinceTime);
-  buffer.StreamMemoryToJSON(aWriter, CorePS::ProcessStartTime(), aSinceTime);
 
   // Data of TaskTracer doesn't belong in the circular buffer.
   if (ActivePS::FeatureTaskTracer(aLock)) {
@@ -2114,35 +2208,37 @@ static void locked_profiler_stream_json_for_this_process(
   aWriter.StartArrayProperty("threads");
   {
     ActivePS::DiscardExpiredDeadProfiledThreads(aLock);
-    Vector<Pair<RegisteredThread*, ProfiledThreadData*>> threads =
+    Vector<std::pair<RegisteredThread*, ProfiledThreadData*>> threads =
         ActivePS::ProfiledThreads(aLock);
     for (auto& thread : threads) {
-      RegisteredThread* registeredThread = thread.first();
+      RegisteredThread* registeredThread = thread.first;
       JSContext* cx =
           registeredThread ? registeredThread->GetJSContext() : nullptr;
-      ProfiledThreadData* profiledThreadData = thread.second();
-      profiledThreadData->StreamJSON(buffer, cx, aWriter,
-                                     CorePS::ProcessName(aLock),
-                                     CorePS::ProcessStartTime(), aSinceTime,
-                                     ActivePS::FeatureJSTracer(aLock));
+      ProfiledThreadData* profiledThreadData = thread.second;
+      profiledThreadData->StreamJSON(
+          buffer, cx, aWriter, CorePS::ProcessName(aLock),
+          CorePS::ProcessStartTime(), aSinceTime,
+          ActivePS::FeatureJSTracer(aLock), aService);
     }
 
 #if defined(GP_OS_android)
     if (ActivePS::FeatureJava(aLock)) {
       java::GeckoJavaSampler::Pause();
 
-      UniquePtr<ProfileBuffer> javaBuffer = CollectJavaThreadProfileData();
+      BlocksRingBuffer bufferManager(
+          BlocksRingBuffer::ThreadSafety::WithoutMutex);
+      UniquePtr<ProfileBuffer> javaBuffer =
+          CollectJavaThreadProfileData(bufferManager);
 
       // Thread id of java Main thread is 0, if we support profiling of other
       // java thread, we have to get thread id and name via JNI.
       RefPtr<ThreadInfo> threadInfo = new ThreadInfo(
           "Java Main Thread", 0, false, CorePS::ProcessStartTime());
-      ProfiledThreadData profiledThreadData(
-          threadInfo, nullptr, ActivePS::FeatureResponsiveness(aLock));
+      ProfiledThreadData profiledThreadData(threadInfo, nullptr);
       profiledThreadData.StreamJSON(*javaBuffer.get(), nullptr, aWriter,
                                     CorePS::ProcessName(aLock),
                                     CorePS::ProcessStartTime(), aSinceTime,
-                                    ActivePS::FeatureJSTracer(aLock));
+                                    ActivePS::FeatureJSTracer(aLock), nullptr);
 
       java::GeckoJavaSampler::Unpause();
     }
@@ -2175,20 +2271,20 @@ static void locked_profiler_stream_json_for_this_process(
   { buffer.StreamPausedRangesToJSON(aWriter, aSinceTime); }
   aWriter.EndArray();
 
-  double collectionEnd = profiler_time();
+  const double collectionEndMs = profiler_time();
 
   // Record timestamps for the collection into the buffer, so that consumers
   // know why we didn't collect any samples for its duration.
   // We put these entries into the buffer after we've collected the profile,
   // so they'll be visible for the *next* profile collection (if they haven't
   // been overwritten due to buffer wraparound by then).
-  buffer.AddEntry(ProfileBufferEntry::CollectionStart(collectionStart));
-  buffer.AddEntry(ProfileBufferEntry::CollectionEnd(collectionEnd));
+  buffer.AddEntry(ProfileBufferEntry::CollectionStart(collectionStartMs));
+  buffer.AddEntry(ProfileBufferEntry::CollectionEnd(collectionEndMs));
 }
 
-bool profiler_stream_json_for_this_process(SpliceableJSONWriter& aWriter,
-                                           double aSinceTime,
-                                           bool aIsShuttingDown) {
+bool profiler_stream_json_for_this_process(
+    SpliceableJSONWriter& aWriter, double aSinceTime, bool aIsShuttingDown,
+    ProfilerCodeAddressService* aService) {
   LOG("profiler_stream_json_for_this_process");
 
   MOZ_RELEASE_ASSERT(CorePS::Exists());
@@ -2199,15 +2295,15 @@ bool profiler_stream_json_for_this_process(SpliceableJSONWriter& aWriter,
     return false;
   }
 
-/*#if !defined(RELEASE_OR_BETA)
+#if !defined(RELEASE_OR_BETA)
   ActivePS::PauseIOInterposer(lock);
-#endif*/
+#endif
 
   locked_profiler_stream_json_for_this_process(lock, aWriter, aSinceTime,
-                                               aIsShuttingDown);
-/*#if !defined(RELEASE_OR_BETA)
+                                               aIsShuttingDown, aService);
+#if !defined(RELEASE_OR_BETA)
   ActivePS::ResumeIOInterposer(lock);
-#endif*/
+#endif
 
   return true;
 }
@@ -2236,6 +2332,7 @@ static char FeatureCategory(uint32_t aFeature) {
   return 'x';
 }
 
+// Doesn't exist if aExitCode is 0
 static void PrintUsageThenExit(int aExitCode) {
   MOZ_RELEASE_ASSERT(NS_IsMainThread());
 
@@ -2254,7 +2351,8 @@ static void PrintUsageThenExit(int aExitCode) {
       "  'prof:3' (least verbose), 'prof:4', 'prof:5' (most verbose).\n"
       "\n"
       "  MOZ_PROFILER_STARTUP\n"
-      "  If set to any value, starts the profiler immediately on start-up.\n"
+      "  If set to any value other than '' or '0'/'N'/'n', starts the\n"
+      "  profiler immediately on start-up.\n"
       "  Useful if you want profile code that runs very early.\n"
       "\n"
       "  MOZ_PROFILER_STARTUP_ENTRIES=<1..>\n"
@@ -2263,7 +2361,7 @@ static void PrintUsageThenExit(int aExitCode) {
       "  started.\n"
       "  If unset, the platform default is used:\n"
       "  %u entries per process, or %u when MOZ_PROFILER_STARTUP is set.\n"
-      "  (%zu bytes per entry -> %zu or %zu total bytes per process)\n"
+      "  (8 bytes per entry -> %u or %u total bytes per process)\n"
       "\n"
       "  MOZ_PROFILER_STARTUP_DURATION=<1..>\n"
       "  If MOZ_PROFILER_STARTUP is set, specifies the maximum life time of\n"
@@ -2273,7 +2371,7 @@ static void PrintUsageThenExit(int aExitCode) {
       "  MOZ_PROFILER_STARTUP_ENTRIES (or its default value), and no\n"
       "  additional time duration restriction will be applied.\n"
       "\n"
-      "  MOZ_PROFILER_STARTUP_INTERVAL=<1..1000>\n"
+      "  MOZ_PROFILER_STARTUP_INTERVAL=<1..%d>\n"
       "  If MOZ_PROFILER_STARTUP is set, specifies the sample interval,\n"
       "  measured in milliseconds, when the profiler is first started.\n"
       "  If unset, the platform default is used.\n"
@@ -2291,10 +2389,11 @@ static void PrintUsageThenExit(int aExitCode) {
       "\n"
       "    Features: (x=unavailable, D/d=default/unavailable,\n"
       "               S/s=MOZ_PROFILER_STARTUP extra default/unavailable)\n",
-      unsigned(PROFILER_DEFAULT_ENTRIES),
-      unsigned(PROFILER_DEFAULT_STARTUP_ENTRIES), sizeof(ProfileBufferEntry),
-      sizeof(ProfileBufferEntry) * PROFILER_DEFAULT_ENTRIES,
-      sizeof(ProfileBufferEntry) * PROFILER_DEFAULT_STARTUP_ENTRIES);
+      unsigned(PROFILER_DEFAULT_ENTRIES.Value()),
+      unsigned(PROFILER_DEFAULT_STARTUP_ENTRIES.Value()),
+      unsigned(PROFILER_DEFAULT_ENTRIES.Value() * 8),
+      unsigned(PROFILER_DEFAULT_STARTUP_ENTRIES.Value() * 8),
+      PROFILER_MAX_INTERVAL);
 
 #define PRINT_FEATURE(n_, str_, Name_, desc_)                                  \
   printf("    %c %5u: \"%s\" (%s)\n", FeatureCategory(ProfilerFeature::Name_), \
@@ -2333,7 +2432,9 @@ static void PrintUsageThenExit(int aExitCode) {
 #endif
   );
 
-  exit(aExitCode);
+  if (aExitCode != 0) {
+    exit(aExitCode);
+  }
 }
 
 ////////////////////////////////////////////////////////////////////////
@@ -2367,13 +2468,17 @@ class Sampler {
 
   // This method suspends and resumes the samplee thread. It calls the passed-in
   // function-like object aProcessRegs (passing it a populated |const
-  // Registers&| arg) while the samplee thread is suspended.
+  // Registers&| arg) while the samplee thread is suspended.  Note that
+  // the aProcessRegs function must be very careful not to do anything that
+  // requires a lock, since we may have interrupted the thread at any point.
+  // As an example, you can't call TimeStamp::Now() since on windows it
+  // takes a lock on the performance counter.
   //
   // Func must be a function-like object of type `void()`.
   template <typename Func>
   void SuspendAndSampleAndResumeThread(
       PSLockRef aLock, const RegisteredThread& aRegisteredThread,
-      const Func& aProcessRegs);
+      const TimeStamp& aNow, const Func& aProcessRegs);
 
  private:
 #if defined(GP_OS_linux) || defined(GP_OS_android)
@@ -2406,7 +2511,7 @@ class Sampler {
 // active. It periodically runs through all registered threads, finds those
 // that should be sampled, then pauses and samples them.
 
-class SamplerThread : public Sampler {
+class SamplerThread {
  public:
   // Creates a sampler thread, but doesn't start it.
   SamplerThread(PSLockRef aLock, uint32_t aActivityGeneration,
@@ -2424,6 +2529,9 @@ class SamplerThread : public Sampler {
   // Best effort timing.
   void SleepMicro(uint32_t aMicroseconds);
 
+  // The sampler used to suspend and sample threads.
+  Sampler mSampler;
+
   // The activity generation, for detecting when the sampler thread must stop.
   const uint32_t mActivityGeneration;
 
@@ -2454,16 +2562,40 @@ static SamplerThread* NewSamplerThread(PSLockRef aLock, uint32_t aGeneration,
 void SamplerThread::Run() {
   PR_SetCurrentThreadName("SamplerThread");
 
+  // Features won't change during this SamplerThread's lifetime, so we can
+  // determine now whether stack sampling is required.
+  const bool noStackSampling = []() {
+    PSAutoLock lock(gPSMutex);
+    if (!ActivePS::Exists(lock)) {
+      // If there is no active profiler, it doesn't matter what we return,
+      // because this thread will exit before any stack sampling is attempted.
+      return false;
+    }
+    return ActivePS::FeatureNoStackSampling(lock);
+  }();
+
+  // Use local BlocksRingBuffer&ProfileBuffer to capture the stack.
+  // (This is to avoid touching the CorePS::BlocksRingBuffer lock while
+  // a thread is suspended, because that thread could be working with
+  // the CorePS::BlocksRingBuffer as well.)
+  BlocksRingBuffer localBlocksRingBuffer(
+      BlocksRingBuffer::ThreadSafety::WithoutMutex);
+  ProfileBuffer localProfileBuffer(localBlocksRingBuffer,
+                                   MakePowerOfTwo32<65536>());
+
+  // Will be kept between collections, to know what each collection does.
+  auto previousState = localBlocksRingBuffer.GetState();
+
   // This will be positive if we are running behind schedule (sampling less
   // frequently than desired) and negative if we are ahead of schedule.
   TimeDuration lastSleepOvershoot = 0;
-  TimeStamp sampleStart = TimeStamp::Now();
+  TimeStamp sampleStart = TimeStamp::NowUnfuzzed();
 
   while (true) {
     // This scope is for |lock|. It ends before we sleep below.
     {
       PSAutoLock lock(gPSMutex);
-      TimeStamp lockAcquired = TimeStamp::Now();
+      TimeStamp lockAcquired = TimeStamp::NowUnfuzzed();
 
       if (!ActivePS::Exists(lock)) {
         return;
@@ -2478,36 +2610,14 @@ void SamplerThread::Run() {
 
       ActivePS::ClearExpiredExitProfiles(lock);
 
-      ActivePS::Buffer(lock).DeleteExpiredStoredMarkers();
-      TimeStamp expiredMarkersCleaned = TimeStamp::Now();
+      TimeStamp expiredMarkersCleaned = TimeStamp::NowUnfuzzed();
 
       if (!ActivePS::IsPaused(lock)) {
-        const Vector<LiveProfiledThreadData>& liveThreads =
-            ActivePS::LiveProfiledThreads(lock);
-
         TimeDuration delta = sampleStart - CorePS::ProcessStartTime();
         ProfileBuffer& buffer = ActivePS::Buffer(lock);
 
-        // Report memory use
-        int64_t rssMemory = 0;
-        int64_t ussMemory = 0;
-        if (ActivePS::FeatureMemory(lock)) {
-          rssMemory = nsMemoryReporterManager::ResidentFast();
-#if defined(GP_OS_linux) || defined(GP_OS_android)
-          ussMemory = nsMemoryReporterManager::ResidentUnique();
-#endif
-          if (rssMemory != 0) {
-            buffer.AddEntry(ProfileBufferEntry::ResidentMemory(rssMemory));
-            if (ussMemory != 0) {
-              buffer.AddEntry(ProfileBufferEntry::UnsharedMemory(ussMemory));
-            }
-          }
-          buffer.AddEntry(ProfileBufferEntry::Time(delta.ToMilliseconds()));
-        }
-
         // handle per-process generic counters
         const Vector<BaseProfilerCount*>& counters = CorePS::Counters(lock);
-        TimeStamp now = TimeStamp::Now();
         for (auto& counter : counters) {
           // create Buffer entries for each counter
           buffer.AddEntry(ProfileBufferEntry::CounterId(counter));
@@ -2525,44 +2635,294 @@ void SamplerThread::Run() {
             buffer.AddEntry(ProfileBufferEntry::Number(number));
           }
         }
-        TimeStamp countersSampled = TimeStamp::Now();
+        TimeStamp countersSampled = TimeStamp::NowUnfuzzed();
 
-        for (auto& thread : liveThreads) {
-          RegisteredThread* registeredThread = thread.mRegisteredThread;
-          ProfiledThreadData* profiledThreadData =
-              thread.mProfiledThreadData.get();
-          RefPtr<ThreadInfo> info = registeredThread->Info();
+        if (!noStackSampling) {
+          const Vector<LiveProfiledThreadData>& liveThreads =
+              ActivePS::LiveProfiledThreads(lock);
 
-          // If the thread is asleep and has been sampled before in the same
-          // sleep episode, find and copy the previous sample, as that's
-          // cheaper than taking a new sample.
-          if (registeredThread->RacyRegisteredThread()
-                  .CanDuplicateLastSampleDueToSleep()) {
-            bool dup_ok = ActivePS::Buffer(lock).DuplicateLastSample(
-                info->ThreadId(), CorePS::ProcessStartTime(),
-                profiledThreadData->LastSample());
-            if (dup_ok) {
-              continue;
+          for (auto& thread : liveThreads) {
+            RegisteredThread* registeredThread = thread.mRegisteredThread;
+            ProfiledThreadData* profiledThreadData =
+                thread.mProfiledThreadData.get();
+            RefPtr<ThreadInfo> info = registeredThread->Info();
+
+            // If the thread is asleep and has been sampled before in the same
+            // sleep episode, find and copy the previous sample, as that's
+            // cheaper than taking a new sample.
+            if (registeredThread->RacyRegisteredThread()
+                    .CanDuplicateLastSampleDueToSleep()) {
+              bool dup_ok = ActivePS::Buffer(lock).DuplicateLastSample(
+                  info->ThreadId(), CorePS::ProcessStartTime(),
+                  profiledThreadData->LastSample());
+              if (dup_ok) {
+                continue;
+              }
             }
-          }
 
-          ThreadResponsiveness* resp =
-              profiledThreadData->GetThreadResponsiveness();
-          if (resp) {
-            resp->Update();
-          }
+            AUTO_PROFILER_STATS(gecko_SamplerThread_Run_DoPeriodicSample);
 
-          now = TimeStamp::Now();
-          SuspendAndSampleAndResumeThread(
-              lock, *registeredThread, [&](const Registers& aRegs) {
-                DoPeriodicSample(lock, *registeredThread, *profiledThreadData,
-                                 now, aRegs);
-                // only report these once per sample-time (if 0 we don't put
-                // them in the buffer, so for the rest of the threads we won't
-                // insert them)
-                rssMemory = 0;
-                ussMemory = 0;
-              });
+            TimeStamp now = TimeStamp::NowUnfuzzed();
+
+            // Add the thread ID now, so we know its position in the main
+            // buffer, which is used by some JS data.
+            // (DoPeriodicSample only knows about the temporary local buffer.)
+            uint64_t samplePos =
+                buffer.AddThreadIdEntry(registeredThread->Info()->ThreadId());
+            profiledThreadData->LastSample() = Some(samplePos);
+
+            // Also add the time, so it's always there after the thread ID, as
+            // expected by the parser. (Other stack data is optional.)
+            TimeDuration delta = now - CorePS::ProcessStartTime();
+            buffer.AddEntry(ProfileBufferEntry::TimeBeforeCompactStack(
+                delta.ToMilliseconds()));
+
+            Maybe<double> unresponsiveDuration_ms;
+
+            // Suspend the thread and collect its stack data in the local
+            // buffer.
+            mSampler.SuspendAndSampleAndResumeThread(
+                lock, *registeredThread, now,
+                [&](const Registers& aRegs, const TimeStamp& aNow) {
+                  DoPeriodicSample(lock, *registeredThread, *profiledThreadData,
+                                   now, aRegs, samplePos, localProfileBuffer);
+
+                  // For "responsiveness", we want the input delay - but if
+                  // there are no events in the input queue (or even if there
+                  // are), we're interested in how long the delay *would* be for
+                  // an input event now, which would be the time to finish the
+                  // current event + the delay caused by any events already in
+                  // the input queue (plus any High priority events).  Events at
+                  // lower priorities (in a PrioritizedEventQueue) than Input
+                  // count for input delay only for the duration that they're
+                  // running, since when they finish, any queued input event
+                  // would run.
+                  //
+                  // Unless we record the time state of all events and queue
+                  // states at all times, this is hard to precisely calculate,
+                  // but we can approximate it well in post-processing with
+                  // RunningEventDelay and RunningEventStart.
+                  //
+                  // RunningEventDelay is the time duration the event was queued
+                  // before starting execution.  RunningEventStart is the time
+                  // the event started. (Note: since we care about Input event
+                  // delays on MainThread, for PrioritizedEventQueues we return
+                  // 0 for RunningEventDelay if the currently running event has
+                  // a lower priority than Input (since Input events won't queue
+                  // behind them).
+                  //
+                  // To directly measure this we would need to record the time
+                  // at which the newest event currently in each queue at time X
+                  // (the sample time) finishes running.  This of course would
+                  // require looking into the future, or recording all this
+                  // state and then post-processing it later. If we were to
+                  // trace every event start and end we could do this, but it
+                  // would have significant overhead to do so (and buffer
+                  // usage).  From a recording of RunningEventDelays and
+                  // RunningEventStarts we can infer the actual delay:
+                  //
+                  // clang-format off
+                  // Event queue: <tail> D  :  C  :  B  : A <head>
+                  // Time inserted (ms): 40 :  20 : 10  : 0
+                  // Run Time (ms):      30 : 100 : 40  : 30
+                  //
+                  // 0    10   20   30   40   50   60   70   80   90  100  110  120  130  140  150  160  170
+                  // [A||||||||||||]
+                  //      ----------[B|||||||||||||||||]
+                  //           -------------------------[C|||||||||||||||||||||||||||||||||||||||||||||||]
+                  //                     -----------------------------------------------------------------[D|||||||||...]
+                  //
+                  // Calculate the delay of a new event added at time t: (run every sample)
+                  //    TimeSinceRunningEventBlockedInputEvents = RunningEventDelay + (now - RunningEventStart);
+                  //    effective_submission = now - TimeSinceRunningEventBlockedInputEvents;
+                  //    delta = (now - last_sample_time);
+                  //    last_sample_time = now;
+                  //    for (t=effective_submission to now) {
+                  //       delay[t] += delta;
+                  //    }
+                  //
+                  // Can be reduced in overhead by:
+                  //    TimeSinceRunningEventBlockedInputEvents = RunningEventDelay + (now - RunningEventStart);
+                  //    effective_submission = now - TimeSinceRunningEventBlockedInputEvents;
+                  //    if (effective_submission != last_submission) {
+                  //      delta = (now - last_submision);
+                  //      // this loop should be made to match each sample point in the range
+                  //      // intead of assuming 1ms sampling as this pseudocode does
+                  //      for (t=last_submission to effective_submission-1) {
+                  //         delay[t] += delta;
+                  //         delta -= 1; // assumes 1ms; adjust as needed to match for()
+                  //      }
+                  //      last_submission = effective_submission;
+                  //    }
+                  //
+                  // Time  Head of queue   Running Event  RunningEventDelay  Delay of       Effective     Started    Calc (submission->now add 10ms)  Final
+                  //                                                         hypothetical   Submission    Running @                                   result
+                  //                                                         event E
+                  // 0        Empty            A                0                30              0           0       @0=10                             30
+                  // 10         B              A                0                60              0           0       @0=20, @10=10                     60
+                  // 20         B              A                0               150              0           0       @0=30, @10=20, @20=10            150
+                  // 30         C              B               20               140             10          30       @10=20, @20=10, @30=0            140
+                  // 40         C              B               20               160                                  @10=30, @20=20...                160
+                  // 50         C              B               20               150                                                                   150
+                  // 60         C              B               20               140                                  @10=50, @20=40...                140
+                  // 70         D              C               50               130             20          70       @20=50, @30=40...                130
+                  // ...
+                  // 160        D              C               50                40                                  @20=140, @30=130...               40
+                  // 170      <empty>          D              140                30             40                   @40=140, @50=130... (rounding)    30
+                  // 180      <empty>          D              140                20             40                   @40=150                           20
+                  // 190      <empty>          D              140                10             40                   @40=160                           10
+                  // 200      <empty>        <empty>            0                 0             NA                                                      0
+                  //
+                  // Function Delay(t) = the time between t and the time at which a hypothetical
+                  // event e would start executing, if e was enqueued at time t.
+                  //
+                  // Delay(-1) = 0 // Before A was enqueued. No wait time, can start running
+                  //               // instantly.
+                  // Delay(0) = 30 // The hypothetical event e got enqueued just after A got
+                  //               // enqueued. It can start running at 30, when A is done.
+                  // Delay(5) = 25
+                  // Delay(10) = 60 // Can start running at 70, after both A and B are done.
+                  // Delay(19) = 51
+                  // Delay(20) = 150 // Can start running at 170, after A, B & C.
+                  // Delay(25) = 145
+                  // Delay(30) = 170 // Can start running at 200, after A, B, C & D.
+                  // Delay(120) = 80
+                  // Delay(200) = 0 // (assuming nothing was enqueued after D)
+                  //
+                  // For every event that gets enqueued, the Delay time will go up by the
+                  // event's running time at the time at which the event is enqueued.
+                  // The Delay function will be a sawtooth of the following shape:
+                  //
+                  //             |\           |...
+                  //             | \          |
+                  //        |\   |  \         |
+                  //        | \  |   \        |
+                  //     |\ |  \ |    \       |
+                  //  |\ | \|   \|     \      |
+                  //  | \|              \     |
+                  // _|                  \____|
+                  //
+                  //
+                  // A more complex example with a PrioritizedEventQueue:
+                  //
+                  // Event queue: <tail> D  :  C  :  B  : A <head>
+                  // Time inserted (ms): 40 :  20 : 10  : 0
+                  // Run Time (ms):      30 : 100 : 40  : 30
+                  // Priority:         Input: Norm: Norm: Norm
+                  //
+                  // 0    10   20   30   40   50   60   70   80   90  100  110  120  130  140  150  160  170
+                  // [A||||||||||||]
+                  //      ----------[B|||||||||||||||||]
+                  //           ----------------------------------------[C|||||||||||||||||||||||||||||||||||||||||||||||]
+                  //                     ---------------[D||||||||||||]
+                  //
+                  //
+                  // Time  Head of queue   Running Event  RunningEventDelay  Delay of       Effective   Started    Calc (submission->now add 10ms)   Final
+                  //                                                         hypothetical   Submission  Running @                                    result
+                  //                                                         event
+                  // 0        Empty            A                0                30              0           0       @0=10                             30
+                  // 10         B              A                0                20              0           0       @0=20, @10=10                     20
+                  // 20         B              A                0                10              0           0       @0=30, @10=20, @20=10             10
+                  // 30         C              B                0                40             30          30       @30=10                            40
+                  // 40         C              B                0                60             30                   @40=10, @30=20                    60
+                  // 50         C              B                0                50             30                   @50=10, @40=20, @30=30            50
+                  // 60         C              B                0                40             30                   @60=10, @50=20, @40=30, @30=40    40
+                  // 70         C              D               30                30             40          70       @60=20, @50=30, @40=40            30
+                  // 80         C              D               30                20             40          70       ...@50=40, @40=50                 20
+                  // 90         C              D               30                10             40          70       ...@60=40, @50=50, @40=60         10
+                  // 100      <empty>          C                0               100             100        100       @100=10                          100
+                  // 110      <empty>          C                0                90             100        100       @110=10, @100=20                  90
+
+                  //
+                  // For PrioritizedEventQueue, the definition of the Delay(t) function is adjusted: the hypothetical event e has Input priority.
+                  // Delay(-1) = 0 // Before A was enqueued. No wait time, can start running
+                  //               // instantly.
+                  // Delay(0) = 30 // The hypothetical input event e got enqueued just after A got
+                  //               // enqueued. It can start running at 30, when A is done.
+                  // Delay(5) = 25
+                  // Delay(10) = 20
+                  // Delay(25) = 5 // B has been queued, but e does not need to wait for B because e has Input priority and B does not.
+                  //               // So e can start running at 30, when A is done.
+                  // Delay(30) = 40 // Can start running at 70, after B is done.
+                  // Delay(40) = 60 // Can start at 100, after B and D are done (D is Input Priority)
+                  // Delay(80) = 20
+                  // Delay(100) = 100 // Wait for C to finish
+
+                  // clang-format on
+                  //
+                  // Alternatively we could insert (recycled instead of
+                  // allocated/freed) input events at every sample period
+                  // (1ms...), and use them to back-calculate the delay.  This
+                  // might also be somewhat expensive, and would require
+                  // guessing at the maximum delay, which would likely be in the
+                  // seconds, and so you'd need 1000's of pre-allocated events
+                  // per queue per thread - so there would be a memory impact as
+                  // well.
+
+                  TimeDuration currentEventDelay;
+                  TimeDuration currentEventRunning;
+                  registeredThread->GetRunningEventDelay(
+                      aNow, currentEventDelay, currentEventRunning);
+
+                  // Note: a different definition of responsiveness than the
+                  // 16ms event injection.
+
+                  // Don't suppress 0's for now; that can be a future
+                  // optimization.  We probably want one zero to be stored
+                  // before we start suppressing, which would be more
+                  // complex.
+                  unresponsiveDuration_ms =
+                      Some(currentEventDelay.ToMilliseconds() +
+                           currentEventRunning.ToMilliseconds());
+                });
+
+            // If we got responsiveness data, store it before the CompactStack.
+            // Note: It is not stored inside the CompactStack so that it doesn't
+            // get incorrectly duplicated when the thread is sleeping.
+            if (unresponsiveDuration_ms.isSome()) {
+              CorePS::CoreBlocksRingBuffer().PutObjects(
+                  ProfileBufferEntry::Kind::UnresponsiveDurationMs,
+                  *unresponsiveDuration_ms);
+            }
+
+            // There *must* be a CompactStack after a TimeBeforeCompactStack;
+            // but note that other entries may have been concurrently inserted
+            // between the TimeBeforeCompactStack above and now. If the captured
+            // sample from `DoPeriodicSample` is complete, copy it into the
+            // global buffer, otherwise add an empty one to satisfy the parser
+            // that expects one.
+            auto state = localBlocksRingBuffer.GetState();
+            if (NS_WARN_IF(state.mClearedBlockCount !=
+                           previousState.mClearedBlockCount)) {
+              LOG("Stack sample too big for local storage, needed %u bytes",
+                  unsigned(state.mRangeEnd.ConvertToU64() -
+                           previousState.mRangeEnd.ConvertToU64()));
+              // There *must* be a CompactStack after a TimeBeforeCompactStack,
+              // even an empty one.
+              CorePS::CoreBlocksRingBuffer().PutObjects(
+                  ProfileBufferEntry::Kind::CompactStack,
+                  UniquePtr<BlocksRingBuffer>(nullptr));
+            } else if (state.mRangeEnd.ConvertToU64() -
+                           previousState.mRangeEnd.ConvertToU64() >=
+                       CorePS::CoreBlocksRingBuffer().BufferLength()->Value()) {
+              LOG("Stack sample too big for profiler storage, needed %u bytes",
+                  unsigned(state.mRangeEnd.ConvertToU64() -
+                           previousState.mRangeEnd.ConvertToU64()));
+              // There *must* be a CompactStack after a TimeBeforeCompactStack,
+              // even an empty one.
+              CorePS::CoreBlocksRingBuffer().PutObjects(
+                  ProfileBufferEntry::Kind::CompactStack,
+                  UniquePtr<BlocksRingBuffer>(nullptr));
+            } else {
+              CorePS::CoreBlocksRingBuffer().PutObjects(
+                  ProfileBufferEntry::Kind::CompactStack,
+                  localBlocksRingBuffer);
+            }
+
+            // Clean up for the next run.
+            localBlocksRingBuffer.Clear();
+            previousState = localBlocksRingBuffer.GetState();
+          }
         }
 
 #if defined(USE_LUL_STACKWALK)
@@ -2573,26 +2933,12 @@ void SamplerThread::Run() {
         // SuspendAndSampleAndResumeThread, which is why it is done here.
         CorePS::Lul(lock)->MaybeShowStats();
 #endif
-        TimeStamp threadsSampled = TimeStamp::Now();
+        TimeStamp threadsSampled = TimeStamp::NowUnfuzzed();
 
-        buffer.AddEntry(
-            ProfileBufferEntry::ProfilerOverheadTime(delta.ToMilliseconds()));
-        buffer.AddEntry(ProfileBufferEntry::ProfilerOverheadDuration(
-            (lockAcquired - sampleStart).ToMilliseconds()));
-        buffer.AddEntry(ProfileBufferEntry::ProfilerOverheadDuration(
-            (expiredMarkersCleaned - lockAcquired).ToMilliseconds()));
-        buffer.AddEntry(ProfileBufferEntry::ProfilerOverheadDuration(
-            (countersSampled - expiredMarkersCleaned).ToMilliseconds()));
-        buffer.AddEntry(ProfileBufferEntry::ProfilerOverheadDuration(
-            (threadsSampled - countersSampled).ToMilliseconds()));
-      }
-
-      Maybe<double> duration = ActivePS::Duration(lock);
-      if (duration) {
-        ActivePS::Buffer(lock).DiscardSamplesBeforeTime(
-            (TimeStamp::Now() - TimeDuration::FromSeconds(*duration) -
-             CorePS::ProcessStartTime())
-                .ToMilliseconds());
+        buffer.CollectOverheadStats(delta, lockAcquired - sampleStart,
+                                    expiredMarkersCleaned - lockAcquired,
+                                    countersSampled - expiredMarkersCleaned,
+                                    threadsSampled - countersSampled);
       }
     }
     // gPSMutex is not held after this point.
@@ -2604,12 +2950,12 @@ void SamplerThread::Run() {
     // actual sleep intervals.
     TimeStamp targetSleepEndTime =
         sampleStart + TimeDuration::FromMicroseconds(mIntervalMicroseconds);
-    TimeStamp beforeSleep = TimeStamp::Now();
+    TimeStamp beforeSleep = TimeStamp::NowUnfuzzed();
     TimeDuration targetSleepDuration = targetSleepEndTime - beforeSleep;
     double sleepTime = std::max(
         0.0, (targetSleepDuration - lastSleepOvershoot).ToMicroseconds());
     SleepMicro(static_cast<uint32_t>(sleepTime));
-    sampleStart = TimeStamp::Now();
+    sampleStart = TimeStamp::NowUnfuzzed();
     lastSleepOvershoot =
         sampleStart - (beforeSleep + TimeDuration::FromMicroseconds(sleepTime));
   }
@@ -2695,7 +3041,8 @@ static uint32_t ParseFeature(const char* aFeature, bool aIsStartup) {
 #undef PARSE_FEATURE_BIT
 
   printf("\nUnrecognized feature \"%s\".\n\n", aFeature);
-  PrintUsageThenExit(1);
+  // Since we may have an old feature we don't implement anymore, don't exit
+  PrintUsageThenExit(0);
   return 0;
 }
 
@@ -2749,8 +3096,7 @@ static ProfilingStack* locked_register_thread(PSLockRef aLock,
     nsCOMPtr<nsIEventTarget> eventTarget = registeredThread->GetEventTarget();
     ProfiledThreadData* profiledThreadData = ActivePS::AddLiveProfiledThread(
         aLock, registeredThread.get(),
-        MakeUnique<ProfiledThreadData>(info, eventTarget,
-                                       ActivePS::FeatureResponsiveness(aLock)));
+        MakeUnique<ProfiledThreadData>(info, eventTarget));
 
     if (ActivePS::FeatureJS(aLock)) {
       // This StartJSSampling() call is on-thread, so we can poll manually to
@@ -2759,7 +3105,7 @@ static ProfilingStack* locked_register_thread(PSLockRef aLock,
       registeredThread->PollJSSampling();
       if (registeredThread->GetJSContext()) {
         profiledThreadData->NotifyReceivedJSContext(
-            ActivePS::Buffer(aLock).mRangeEnd);
+            ActivePS::Buffer(aLock).BufferRangeEnd());
       }
     }
   }
@@ -2793,7 +3139,7 @@ static void NotifyObservers(const char* aTopic,
   }
 }
 
-static void NotifyProfilerStarted(const int aCapacity,
+static void NotifyProfilerStarted(const PowerOfTwo32& aCapacity,
                                   const Maybe<double>& aDuration,
                                   double aInterval, uint32_t aFeatures,
                                   const char** aFilters,
@@ -2803,21 +3149,22 @@ static void NotifyProfilerStarted(const int aCapacity,
     filtersArray.AppendElement(aFilters[i]);
   }
 
-  nsCOMPtr<nsIProfilerStartParams> params = new nsProfilerStartParams(
-      aCapacity, aDuration, aInterval, aFeatures, std::move(filtersArray));
+  nsCOMPtr<nsIProfilerStartParams> params =
+      new nsProfilerStartParams(aCapacity.Value(), aDuration, aInterval,
+                                aFeatures, std::move(filtersArray));
 
   ProfilerParent::ProfilerStarted(params);
   NotifyObservers("profiler-started", params);
 }
 
-static void locked_profiler_start(PSLockRef aLock, uint32_t aCapacity,
+static void locked_profiler_start(PSLockRef aLock, PowerOfTwo32 aCapacity,
                                   double aInterval, uint32_t aFeatures,
                                   const char** aFilters, uint32_t aFilterCount,
                                   const Maybe<double>& aDuration);
 
 // This basically duplicates AutoProfilerLabel's constructor.
-ProfilingStack* MozGlueLabelEnter(const char* aLabel,
-                                  const char* aDynamicString, void* aSp) {
+static void* MozGlueLabelEnter(const char* aLabel, const char* aDynamicString,
+                               void* aSp) {
   ProfilingStack* profilingStack = AutoProfilerLabel::sProfilingStack.get();
   if (profilingStack) {
     profilingStack->pushLabelFrame(aLabel, aDynamicString, aSp,
@@ -2827,9 +3174,9 @@ ProfilingStack* MozGlueLabelEnter(const char* aLabel,
 }
 
 // This basically duplicates AutoProfilerLabel's destructor.
-void MozGlueLabelExit(ProfilingStack* sProfilingStack) {
+static void MozGlueLabelExit(void* sProfilingStack) {
   if (sProfilingStack) {
-    sProfilingStack->pop();
+    reinterpret_cast<ProfilingStack*>(sProfilingStack)->pop();
   }
 }
 
@@ -2855,6 +3202,17 @@ static Vector<const char*> SplitAtCommas(const char* aString,
   return array;
 }
 
+void profiler_init_threadmanager() {
+  LOG("profiler_init_threadmanager");
+
+  PSAutoLock lock(gPSMutex);
+  RegisteredThread* registeredThread =
+      TLSRegisteredThread::RegisteredThread(lock);
+  if (!registeredThread->GetEventTarget()) {
+    registeredThread->ResetMainThread(NS_GetCurrentThreadNoCreate());
+  }
+}
+
 void profiler_init(void* aStackTop) {
   LOG("profiler_init");
 
@@ -2863,7 +3221,7 @@ void profiler_init(void* aStackTop) {
   MOZ_RELEASE_ASSERT(!CorePS::Exists());
 
   if (getenv("MOZ_PROFILER_HELP")) {
-    PrintUsageThenExit(0);  // terminates execution
+    PrintUsageThenExit(1);  // terminates execution
   }
 
   SharedLibraryInfo::Initialize();
@@ -2877,7 +3235,7 @@ void profiler_init(void* aStackTop) {
   MOZ_RELEASE_ASSERT(filters.append("Compositor"));
   MOZ_RELEASE_ASSERT(filters.append("DOM Worker"));
 
-  uint32_t capacity = PROFILER_DEFAULT_ENTRIES;
+  PowerOfTwo32 capacity = PROFILER_DEFAULT_ENTRIES;
   Maybe<double> duration = Nothing();
   double interval = PROFILER_DEFAULT_INTERVAL;
 
@@ -2903,9 +3261,6 @@ void profiler_init(void* aStackTop) {
     }
 #endif
 
-    // Setup support for pushing/popping labels in mozglue.
-    RegisterProfilerLabelEnterExit(MozGlueLabelEnter, MozGlueLabelExit);
-
     // (Linux-only) We could create CorePS::mLul and read unwind info into it
     // at this point. That would match the lifetime implied by destruction of
     // it in profiler_shutdown() just below. However, that gives a big delay on
@@ -2913,7 +3268,10 @@ void profiler_init(void* aStackTop) {
     // created on demand at the first call to PlatformStart().
 
     const char* startupEnv = getenv("MOZ_PROFILER_STARTUP");
-    if (!startupEnv || startupEnv[0] == '\0') {
+    if (!startupEnv || startupEnv[0] == '\0' ||
+        ((startupEnv[0] == '0' || startupEnv[0] == 'N' ||
+          startupEnv[0] == 'n') &&
+         startupEnv[1] == '\0')) {
       return;
     }
 
@@ -2927,12 +3285,13 @@ void profiler_init(void* aStackTop) {
       errno = 0;
       long capacityLong = strtol(startupCapacity, nullptr, 10);
       // `long` could be 32 or 64 bits, so we force a 64-bit comparison with
-      // the maximum 32-bit unsigned number.
+      // the maximum 32-bit signed number (as more than that is clamped down to
+      // 2^31 anyway).
       if (errno == 0 && capacityLong > 0 &&
           static_cast<uint64_t>(capacityLong) <=
-              static_cast<uint64_t>(UINT32_MAX)) {
-        capacity = static_cast<uint32_t>(capacityLong);
-        LOG("- MOZ_PROFILER_STARTUP_ENTRIES = %u", unsigned(capacity));
+              static_cast<uint64_t>(INT32_MAX)) {
+        capacity = PowerOfTwo32(static_cast<uint32_t>(capacityLong));
+        LOG("- MOZ_PROFILER_STARTUP_ENTRIES = %u", unsigned(capacity.Value()));
       } else {
         LOG("- MOZ_PROFILER_STARTUP_ENTRIES not a valid integer: %s",
             startupCapacity);
@@ -2960,7 +3319,7 @@ void profiler_init(void* aStackTop) {
     if (startupInterval && startupInterval[0] != '\0') {
       errno = 0;
       interval = PR_strtod(startupInterval, nullptr);
-      if (errno == 0 && interval > 0.0 && interval <= 1000.0) {
+      if (errno == 0 && interval > 0.0 && interval <= PROFILER_MAX_INTERVAL) {
         LOG("- MOZ_PROFILER_STARTUP_INTERVAL = %f", interval);
       } else {
         LOG("- MOZ_PROFILER_STARTUP_INTERVAL not a valid float: %s",
@@ -3009,11 +3368,9 @@ void profiler_init(void* aStackTop) {
   }
 
 #if defined(MOZ_REPLACE_MALLOC) && defined(MOZ_PROFILER_MEMORY)
-  if (ProfilerFeature::HasMemory(features)) {
-    // start counting memory allocations (outside of lock because this may call
-    // profiler_add_sampled_counter which would attempt to take the lock.)
-    mozilla::profiler::install_memory_counter(true);
-  }
+  // Start counting memory allocations (outside of lock because this may call
+  // profiler_add_sampled_counter which would attempt to take the lock.)
+  mozilla::profiler::install_memory_hooks();
 #endif
 
   // We do this with gPSMutex unlocked. The comment in profiler_stop() explains
@@ -3046,11 +3403,11 @@ void profiler_shutdown() {
     if (ActivePS::Exists(lock)) {
       const char* filename = getenv("MOZ_PROFILER_SHUTDOWN");
       if (filename) {
-/*#if !defined(RELEASE_OR_BETA)
+#if !defined(RELEASE_OR_BETA)
         // Attempting to record the I/O we are doing to the shutdown profile
         // file while we are locked will deadlock.
         ActivePS::UnregisterIOInterposer(lock);
-#endif*/
+#endif
         locked_profiler_save_profile_to_file(lock, filename,
                                              /* aIsShuttingDown */ true);
       }
@@ -3079,7 +3436,8 @@ void profiler_shutdown() {
 }
 
 static bool WriteProfileToJSONWriter(SpliceableChunkedJSONWriter& aWriter,
-                                     double aSinceTime, bool aIsShuttingDown) {
+                                     double aSinceTime, bool aIsShuttingDown,
+                                     ProfilerCodeAddressService* aService) {
   LOG("WriteProfileToJSONWriter");
 
   MOZ_RELEASE_ASSERT(CorePS::Exists());
@@ -3087,7 +3445,7 @@ static bool WriteProfileToJSONWriter(SpliceableChunkedJSONWriter& aWriter,
   aWriter.Start();
   {
     if (!profiler_stream_json_for_this_process(aWriter, aSinceTime,
-                                               aIsShuttingDown)) {
+                                               aIsShuttingDown, aService)) {
       return false;
     }
 
@@ -3110,8 +3468,12 @@ UniquePtr<char[]> profiler_get_profile(double aSinceTime,
                                        bool aIsShuttingDown) {
   LOG("profiler_get_profile");
 
+  UniquePtr<ProfilerCodeAddressService> service =
+      profiler_code_address_service_for_presymbolication();
+
   SpliceableChunkedJSONWriter b;
-  if (!WriteProfileToJSONWriter(b, aSinceTime, aIsShuttingDown)) {
+  if (!WriteProfileToJSONWriter(b, aSinceTime, aIsShuttingDown,
+                                service.get())) {
     return nullptr;
   }
   return b.WriteFunc()->CopyData();
@@ -3122,8 +3484,12 @@ void profiler_get_profile_json_into_lazily_allocated_buffer(
     bool aIsShuttingDown) {
   LOG("profiler_get_profile_json_into_lazily_allocated_buffer");
 
+  UniquePtr<ProfilerCodeAddressService> service =
+      profiler_code_address_service_for_presymbolication();
+
   SpliceableChunkedJSONWriter b;
-  if (!WriteProfileToJSONWriter(b, aSinceTime, aIsShuttingDown)) {
+  if (!WriteProfileToJSONWriter(b, aSinceTime, aIsShuttingDown,
+                                service.get())) {
     return;
   }
 
@@ -3152,7 +3518,7 @@ void profiler_get_start_params(int* aCapacity, Maybe<double>* aDuration,
     return;
   }
 
-  *aCapacity = ActivePS::Capacity(lock);
+  *aCapacity = ActivePS::Capacity(lock).Value();
   *aDuration = ActivePS::Duration(lock);
   *aInterval = ActivePS::Interval(lock);
   *aFeatures = ActivePS::Features(lock);
@@ -3178,7 +3544,8 @@ void GetProfilerEnvVarsForChildProcess(
   }
 
   aSetEnv("MOZ_PROFILER_STARTUP", "1");
-  auto capacityString = Smprintf("%d", ActivePS::Capacity(lock));
+  auto capacityString =
+      Smprintf("%u", unsigned(ActivePS::Capacity(lock).Value()));
   aSetEnv("MOZ_PROFILER_STARTUP_ENTRIES", capacityString.get());
 
   // Use AppendFloat instead of Smprintf with %f because the decimal
@@ -3256,7 +3623,7 @@ static void locked_profiler_save_profile_to_file(PSLockRef aLock,
     w.Start();
     {
       locked_profiler_stream_json_for_this_process(aLock, w, /* sinceTime */ 0,
-                                                   aIsShuttingDown);
+                                                   aIsShuttingDown, nullptr);
 
       w.StartArrayProperty("processes");
       Vector<nsCString> exitProfiles = ActivePS::MoveExitProfiles(aLock);
@@ -3301,9 +3668,7 @@ Maybe<ProfilerBufferInfo> profiler_get_buffer_info() {
     return Nothing();
   }
 
-  return Some(ProfilerBufferInfo{ActivePS::Buffer(lock).mRangeStart,
-                                 ActivePS::Buffer(lock).mRangeEnd,
-                                 ActivePS::Capacity(lock)});
+  return Some(ActivePS::Buffer(lock).GetProfilerBufferInfo());
 }
 
 static void PollJSSamplingForCurrentThread() {
@@ -3342,13 +3707,13 @@ static void TriggerPollJSSamplingOnMainThread() {
   }
 }
 
-static void locked_profiler_start(PSLockRef aLock, uint32_t aCapacity,
+static void locked_profiler_start(PSLockRef aLock, PowerOfTwo32 aCapacity,
                                   double aInterval, uint32_t aFeatures,
                                   const char** aFilters, uint32_t aFilterCount,
                                   const Maybe<double>& aDuration) {
   if (LOG_TEST) {
     LOG("locked_profiler_start");
-    LOG("- capacity  = %d", aCapacity);
+    LOG("- capacity  = %u", unsigned(aCapacity.Value()));
     LOG("- duration  = %.2f", aDuration ? *aDuration : -1);
     LOG("- interval = %.2f", aInterval);
 
@@ -3373,7 +3738,11 @@ static void locked_profiler_start(PSLockRef aLock, uint32_t aCapacity,
 #endif
 
   // Fall back to the default values if the passed-in values are unreasonable.
-  uint32_t capacity = aCapacity > 0 ? aCapacity : PROFILER_DEFAULT_ENTRIES;
+  // Less than 8192 entries (65536 bytes) may not be enough for the most complex
+  // stack, so we should be able to store at least one full stack.
+  // TODO: Review magic numbers.
+  PowerOfTwo32 capacity =
+      (aCapacity.Value() >= 8192u) ? aCapacity : PROFILER_DEFAULT_ENTRIES;
   Maybe<double> duration = aDuration;
 
   if (aDuration && *aDuration <= 0) {
@@ -3426,8 +3795,7 @@ static void locked_profiler_start(PSLockRef aLock, uint32_t aCapacity,
       nsCOMPtr<nsIEventTarget> eventTarget = registeredThread->GetEventTarget();
       ProfiledThreadData* profiledThreadData = ActivePS::AddLiveProfiledThread(
           aLock, registeredThread.get(),
-          MakeUnique<ProfiledThreadData>(
-              info, eventTarget, ActivePS::FeatureResponsiveness(aLock)));
+          MakeUnique<ProfiledThreadData>(info, eventTarget));
       if (ActivePS::FeatureJS(aLock)) {
         registeredThread->StartJSSampling(ActivePS::JSFlags(aLock));
         if (info->ThreadId() == tid) {
@@ -3448,6 +3816,9 @@ static void locked_profiler_start(PSLockRef aLock, uint32_t aCapacity,
     }
   }
 
+  // Setup support for pushing/popping labels in mozglue.
+  RegisterProfilerLabelEnterExit(MozGlueLabelEnter, MozGlueLabelExit);
+
 #ifdef MOZ_TASK_TRACER
   if (ActivePS::FeatureTaskTracer(aLock)) {
     tasktracer::StartLogging();
@@ -3465,13 +3836,19 @@ static void locked_profiler_start(PSLockRef aLock, uint32_t aCapacity,
   }
 #endif
 
+#if defined(MOZ_REPLACE_MALLOC) && defined(MOZ_PROFILER_MEMORY)
+  if (ActivePS::FeatureNativeAllocations(aLock)) {
+    mozilla::profiler::enable_native_allocations();
+  }
+#endif
+
   // At the very end, set up RacyFeatures.
   RacyFeatures::SetActive(ActivePS::Features(aLock));
 }
 
-void profiler_start(uint32_t aCapacity, double aInterval, uint32_t aFeatures,
-                    const char** aFilters, uint32_t aFilterCount,
-                    const Maybe<double>& aDuration) {
+void profiler_start(PowerOfTwo32 aCapacity, double aInterval,
+                    uint32_t aFeatures, const char** aFilters,
+                    uint32_t aFilterCount, const Maybe<double>& aDuration) {
   LOG("profiler_start");
 
   SamplerThread* samplerThread = nullptr;
@@ -3493,11 +3870,9 @@ void profiler_start(uint32_t aCapacity, double aInterval, uint32_t aFeatures,
   }
 
 #if defined(MOZ_REPLACE_MALLOC) && defined(MOZ_PROFILER_MEMORY)
-  if (ProfilerFeature::HasMemory(aFeatures)) {
-    // start counting memory allocations (outside of lock because this may call
-    // profiler_add_sampled_counter which would attempt to take the lock.)
-    mozilla::profiler::install_memory_counter(true);
-  }
+  // Start counting memory allocations (outside of lock because this may call
+  // profiler_add_sampled_counter which would attempt to take the lock.)
+  mozilla::profiler::install_memory_hooks();
 #endif
 
   // We do these operations with gPSMutex unlocked. The comments in
@@ -3511,7 +3886,7 @@ void profiler_start(uint32_t aCapacity, double aInterval, uint32_t aFeatures,
                         aFilterCount);
 }
 
-void profiler_ensure_started(uint32_t aCapacity, double aInterval,
+void profiler_ensure_started(PowerOfTwo32 aCapacity, double aInterval,
                              uint32_t aFeatures, const char** aFilters,
                              uint32_t aFilterCount,
                              const Maybe<double>& aDuration) {
@@ -3533,12 +3908,6 @@ void profiler_ensure_started(uint32_t aCapacity, double aInterval,
                             aFilters, aFilterCount)) {
         // Stop and restart with different settings.
         samplerThread = locked_profiler_stop(lock);
-#if defined(MOZ_REPLACE_MALLOC) && defined(MOZ_PROFILER_MEMORY)
-        if (!ProfilerFeature::HasMemory(aFeatures)) {
-          // Ensure we don't record memory measurements anymore (if we were).
-          mozilla::profiler::install_memory_counter(false);
-        }
-#endif
         locked_profiler_start(lock, aCapacity, aInterval, aFeatures, aFilters,
                               aFilterCount, aDuration);
         startedProfiler = true;
@@ -3551,15 +3920,6 @@ void profiler_ensure_started(uint32_t aCapacity, double aInterval,
     }
   }
 
-#if defined(MOZ_REPLACE_MALLOC) && defined(MOZ_PROFILER_MEMORY)
-  if (startedProfiler && ProfilerFeature::HasMemory(aFeatures)) {
-    // start counting memory allocations (outside of lock because this may
-    // call profiler_add_sampled_counter which would attempt to take the
-    // lock.)
-    mozilla::profiler::install_memory_counter(true);
-  }
-#endif
-
   // We do these operations with gPSMutex unlocked. The comments in
   // profiler_stop() explain why.
   if (samplerThread) {
@@ -3582,10 +3942,6 @@ static MOZ_MUST_USE SamplerThread* locked_profiler_stop(PSLockRef aLock) {
   // At the very start, clear RacyFeatures.
   RacyFeatures::SetInactive();
 
-#if defined(MOZ_REPLACE_MALLOC) && defined(MOZ_PROFILER_MEMORY)
-  mozilla::profiler::install_memory_counter(false);
-#endif
-
 #if defined(GP_OS_android)
   if (ActivePS::FeatureJava(aLock)) {
     java::GeckoJavaSampler::Stop();
@@ -3598,6 +3954,9 @@ static MOZ_MUST_USE SamplerThread* locked_profiler_stop(PSLockRef aLock) {
   }
 #endif
 
+  // Remove support for pushing/popping labels in mozglue.
+  RegisterProfilerLabelEnterExit(nullptr, nullptr);
+
   // Stop sampling live threads.
   int tid = profiler_current_thread_id();
   const Vector<LiveProfiledThreadData>& liveProfiledThreads =
@@ -3621,6 +3980,12 @@ static MOZ_MUST_USE SamplerThread* locked_profiler_stop(PSLockRef aLock) {
     }
   }
 
+#if defined(MOZ_REPLACE_MALLOC) && defined(MOZ_PROFILER_MEMORY)
+  if (ActivePS::FeatureNativeAllocations(aLock)) {
+    mozilla::profiler::disable_native_allocations();
+  }
+#endif
+
   // The Stop() call doesn't actually stop Run(); that happens in this
   // function's caller when the sampler thread is destroyed. Stop() just gives
   // the SamplerThread a chance to do some cleanup with gPSMutex locked.
@@ -3635,6 +4000,12 @@ void profiler_stop() {
 
   MOZ_RELEASE_ASSERT(CorePS::Exists());
 
+#if defined(MOZ_REPLACE_MALLOC) && defined(MOZ_PROFILER_MEMORY)
+  // Remove the hooks early, as native allocations (if they are on) can be
+  // quite expensive.
+  mozilla::profiler::remove_memory_hooks();
+#endif
+
   SamplerThread* samplerThread;
   {
     PSAutoLock lock(gPSMutex);
@@ -3690,6 +4061,7 @@ void profiler_pause() {
       return;
     }
 
+    RacyFeatures::SetPaused();
     ActivePS::SetIsPaused(lock, true);
     ActivePS::Buffer(lock).AddEntry(ProfileBufferEntry::Pause(profiler_time()));
   }
@@ -3714,6 +4086,7 @@ void profiler_resume() {
     ActivePS::Buffer(lock).AddEntry(
         ProfileBufferEntry::Resume(profiler_time()));
     ActivePS::SetIsPaused(lock, false);
+    RacyFeatures::SetUnpaused();
   }
 
   // gPSMutex must be unlocked when we notify, to avoid potential deadlocks.
@@ -3926,13 +4299,18 @@ void profiler_js_interrupt_callback() {
 double profiler_time() {
   MOZ_RELEASE_ASSERT(CorePS::Exists());
 
-  TimeDuration delta = TimeStamp::Now() - CorePS::ProcessStartTime();
+  TimeDuration delta = TimeStamp::NowUnfuzzed() - CorePS::ProcessStartTime();
   return delta.ToMilliseconds();
 }
 
 UniqueProfilerBacktrace profiler_get_backtrace() {
   MOZ_RELEASE_ASSERT(CorePS::Exists());
 
+  // Fast racy early return.
+  if (!profiler_is_active()) {
+    return nullptr;
+  }
+
   PSAutoLock lock(gPSMutex);
 
   if (!ActivePS::Exists(lock) || ActivePS::FeaturePrivacy(lock)) {
@@ -3942,13 +4320,16 @@ UniqueProfilerBacktrace profiler_get_backtrace() {
   RegisteredThread* registeredThread =
       TLSRegisteredThread::RegisteredThread(lock);
   if (!registeredThread) {
-    MOZ_ASSERT(registeredThread);
+    // If this was called from a non-registered thread, return a nullptr
+    // and do no more work. This can happen from a memory hook. Before
+    // the allocation tracking there was a MOZ_ASSERT() here checking
+    // for the existence of a registeredThread.
     return nullptr;
   }
 
   int tid = profiler_current_thread_id();
 
-  TimeStamp now = TimeStamp::Now();
+  TimeStamp now = TimeStamp::NowUnfuzzed();
 
   Registers regs;
 #if defined(HAVE_NATIVE_UNWIND)
@@ -3957,30 +4338,35 @@ UniqueProfilerBacktrace profiler_get_backtrace() {
   regs.Clear();
 #endif
 
-  // 1000 should be plenty for a single backtrace.
-  auto buffer = MakeUnique<ProfileBuffer>(1000);
+  // 65536 bytes should be plenty for a single backtrace.
+  auto bufferManager = MakeUnique<BlocksRingBuffer>(
+      BlocksRingBuffer::ThreadSafety::WithoutMutex);
+  auto buffer =
+      MakeUnique<ProfileBuffer>(*bufferManager, MakePowerOfTwo32<65536>());
 
   DoSyncSample(lock, *registeredThread, now, regs, *buffer.get());
 
-  return UniqueProfilerBacktrace(
-      new ProfilerBacktrace("SyncProfile", tid, std::move(buffer)));
+  return UniqueProfilerBacktrace(new ProfilerBacktrace(
+      "SyncProfile", tid, std::move(bufferManager), std::move(buffer)));
 }
 
 void ProfilerBacktraceDestructor::operator()(ProfilerBacktrace* aBacktrace) {
   delete aBacktrace;
 }
 
-static void racy_profiler_add_marker(
-    const char* aMarkerName, JS::ProfilingCategoryPair aCategoryPair,
-    UniquePtr<ProfilerMarkerPayload> aPayload) {
+static void racy_profiler_add_marker(const char* aMarkerName,
+                                     JS::ProfilingCategoryPair aCategoryPair,
+                                     const ProfilerMarkerPayload* aPayload) {
   MOZ_RELEASE_ASSERT(CorePS::Exists());
 
-  // We don't assert that RacyFeatures::IsActiveWithoutPrivacy() or
-  // RacyRegisteredThread::IsBeingProfiled() is true here, because it's
-  // possible that the result has changed since we tested it in the caller.
-  //
-  // Because of this imprecision it's possible to miss a marker or record one
-  // we shouldn't. Either way is not a big deal.
+  // This function is hot enough that we use RacyFeatures, not ActivePS.
+  if (!profiler_can_accept_markers()) {
+    return;
+  }
+
+  // Note that it's possible that the above test would change again before we
+  // actually record the marker. Because of this imprecision it's possible to
+  // miss a marker or record one we shouldn't. Either way is not a big deal.
 
   RacyRegisteredThread* racyRegisteredThread =
       TLSRegisteredThread::RacyRegisteredThread();
@@ -3990,41 +4376,59 @@ static void racy_profiler_add_marker(
 
   TimeStamp origin = (aPayload && !aPayload->GetStartTime().IsNull())
                          ? aPayload->GetStartTime()
-                         : TimeStamp::Now();
+                         : TimeStamp::NowUnfuzzed();
   TimeDuration delta = origin - CorePS::ProcessStartTime();
-  racyRegisteredThread->AddPendingMarker(
-      aMarkerName, aCategoryPair, std::move(aPayload), delta.ToMilliseconds());
+  CorePS::CoreBlocksRingBuffer().PutObjects(
+      ProfileBufferEntry::Kind::MarkerData, racyRegisteredThread->ThreadId(),
+      WrapBlocksRingBufferUnownedCString(aMarkerName),
+      static_cast<uint32_t>(aCategoryPair), aPayload, delta.ToMilliseconds());
 }
 
 void profiler_add_marker(const char* aMarkerName,
                          JS::ProfilingCategoryPair aCategoryPair,
-                         UniquePtr<ProfilerMarkerPayload> aPayload) {
-  MOZ_RELEASE_ASSERT(CorePS::Exists());
-
-  // This function is hot enough that we use RacyFeatures, not ActivePS.
-  if (!RacyFeatures::IsActiveWithoutPrivacy()) {
-    return;
-  }
-
-  racy_profiler_add_marker(aMarkerName, aCategoryPair, std::move(aPayload));
+                         const ProfilerMarkerPayload& aPayload) {
+  racy_profiler_add_marker(aMarkerName, aCategoryPair, &aPayload);
 }
 
 void profiler_add_marker(const char* aMarkerName,
                          JS::ProfilingCategoryPair aCategoryPair) {
-  profiler_add_marker(aMarkerName, aCategoryPair, nullptr);
+  racy_profiler_add_marker(aMarkerName, aCategoryPair, nullptr);
 }
 
 // This is a simplified version of profiler_add_marker that can be easily passed
 // into the JS engine.
 void profiler_add_js_marker(const char* aMarkerName) {
-  profiler_add_marker(aMarkerName, JS::ProfilingCategoryPair::JS, nullptr);
+  AUTO_PROFILER_STATS(add_marker);
+  profiler_add_marker(aMarkerName, JS::ProfilingCategoryPair::JS);
 }
 
 void profiler_add_js_allocation_marker(JS::RecordAllocationInfo&& info) {
+  if (!profiler_can_accept_markers()) {
+    return;
+  }
+  AUTO_PROFILER_STATS(add_marker_with_JsAllocationMarkerPayload);
   profiler_add_marker(
       "JS allocation", JS::ProfilingCategoryPair::JS,
-      MakeUnique<JsAllocationMarkerPayload>(TimeStamp::Now(), std::move(info),
-                                            profiler_get_backtrace()));
+      JsAllocationMarkerPayload(TimeStamp::Now(), std::move(info),
+                                profiler_get_backtrace()));
+}
+
+// Memory hooks can re-enter into the locked profiler state. This function
+// provides a check to avoid sampling memory allocations while the profiler
+// could potentially be locked on the current thread. There will be many false
+// positives with this check. See PSMutex::CouldBeLockedOnCurrentThread.
+bool profiler_could_be_locked_on_current_thread() {
+  return gPSMutex.CouldBeLockedOnCurrentThread();
+}
+
+void profiler_add_native_allocation_marker(const int64_t aSize) {
+  if (!profiler_can_accept_markers()) {
+    return;
+  }
+  AUTO_PROFILER_STATS(add_marker_with_NativeAllocationMarkerPayload);
+  profiler_add_marker("Native allocation", JS::ProfilingCategoryPair::OTHER,
+                      NativeAllocationMarkerPayload(TimeStamp::Now(), aSize,
+                                                    profiler_get_backtrace()));
 }
 
 void profiler_add_network_marker(
@@ -4032,7 +4436,7 @@ void profiler_add_network_marker(
     mozilla::TimeStamp aStart, mozilla::TimeStamp aEnd, int64_t aCount,
     mozilla::net::CacheDisposition aCacheDisposition,
     const mozilla::net::TimingStruct* aTimings, nsIURI* aRedirectURI) {
-  if (!profiler_is_active()) {
+  if (!profiler_can_accept_markers()) {
     return;
   }
   // These do allocations/frees/etc; avoid if not active
@@ -4048,55 +4452,55 @@ void profiler_add_network_marker(
   uint32_t id = static_cast<uint32_t>(aChannelId & 0xFFFFFFFF);
   char name[2048];
   SprintfLiteral(name, "Load %d: %s", id, PromiseFlatCString(spec).get());
+  AUTO_PROFILER_STATS(add_marker_with_NetworkMarkerPayload);
   profiler_add_marker(
       name, JS::ProfilingCategoryPair::NETWORK,
-      MakeUnique<NetworkMarkerPayload>(
-          static_cast<int64_t>(aChannelId), PromiseFlatCString(spec).get(),
-          aType, aStart, aEnd, aPriority, aCount, aCacheDisposition, aTimings,
-          PromiseFlatCString(redirect_spec).get()));
+      NetworkMarkerPayload(static_cast<int64_t>(aChannelId),
+                           PromiseFlatCString(spec).get(), aType, aStart, aEnd,
+                           aPriority, aCount, aCacheDisposition, aTimings,
+                           PromiseFlatCString(redirect_spec).get()));
 }
 
-// This logic needs to add a marker for a different thread, so we actually need
-// to lock here.
 void profiler_add_marker_for_thread(int aThreadId,
                                     JS::ProfilingCategoryPair aCategoryPair,
                                     const char* aMarkerName,
                                     UniquePtr<ProfilerMarkerPayload> aPayload) {
   MOZ_RELEASE_ASSERT(CorePS::Exists());
 
-  PSAutoLock lock(gPSMutex);
-  if (!ActivePS::Exists(lock)) {
+  if (!profiler_can_accept_markers()) {
     return;
   }
 
-  // Create the ProfilerMarker which we're going to store.
-  TimeStamp origin = (aPayload && !aPayload->GetStartTime().IsNull())
-                         ? aPayload->GetStartTime()
-                         : TimeStamp::Now();
-  TimeDuration delta = origin - CorePS::ProcessStartTime();
-  ProfilerMarker* marker =
-      new ProfilerMarker(aMarkerName, aCategoryPair, aThreadId,
-                         std::move(aPayload), delta.ToMilliseconds());
-
 #ifdef DEBUG
-  // Assert that our thread ID makes sense
-  bool realThread = false;
-  const Vector<UniquePtr<RegisteredThread>>& registeredThreads =
-      CorePS::RegisteredThreads(lock);
-  for (auto& thread : registeredThreads) {
-    RefPtr<ThreadInfo> info = thread->Info();
-    if (info->ThreadId() == aThreadId) {
-      realThread = true;
-      break;
+  {
+    PSAutoLock lock(gPSMutex);
+    if (!ActivePS::Exists(lock)) {
+      return;
     }
+
+    // Assert that our thread ID makes sense
+    bool realThread = false;
+    const Vector<UniquePtr<RegisteredThread>>& registeredThreads =
+        CorePS::RegisteredThreads(lock);
+    for (auto& thread : registeredThreads) {
+      RefPtr<ThreadInfo> info = thread->Info();
+      if (info->ThreadId() == aThreadId) {
+        realThread = true;
+        break;
+      }
+    }
+    MOZ_ASSERT(realThread, "Invalid thread id");
   }
-  MOZ_ASSERT(realThread, "Invalid thread id");
 #endif
 
-  // Insert the marker into the buffer
-  ProfileBuffer& buffer = ActivePS::Buffer(lock);
-  buffer.AddStoredMarker(marker);
-  buffer.AddEntry(ProfileBufferEntry::Marker(marker));
+  TimeStamp origin = (aPayload && !aPayload->GetStartTime().IsNull())
+                         ? aPayload->GetStartTime()
+                         : TimeStamp::NowUnfuzzed();
+  TimeDuration delta = origin - CorePS::ProcessStartTime();
+  CorePS::CoreBlocksRingBuffer().PutObjects(
+      ProfileBufferEntry::Kind::MarkerData, aThreadId,
+      WrapBlocksRingBufferUnownedCString(aMarkerName),
+      static_cast<uint32_t>(aCategoryPair), aPayload, delta.ToMilliseconds());
 }
 
 void profiler_tracing(const char* aCategoryString, const char* aMarkerName,
@@ -4108,13 +4512,14 @@ void profiler_tracing(const char* aCategoryString, const char* aMarkerName,
   VTUNE_TRACING(aMarkerName, aKind);
 
   // This function is hot enough that we use RacyFeatures, notActivePS.
-  if (!RacyFeatures::IsActiveWithoutPrivacy()) {
+  if (!profiler_can_accept_markers()) {
     return;
   }
 
-  auto payload = MakeUnique<TracingMarkerPayload>(
-      aCategoryString, aKind, aDocShellId, aDocShellHistoryId);
-  racy_profiler_add_marker(aMarkerName, aCategoryPair, std::move(payload));
+  AUTO_PROFILER_STATS(add_marker_with_TracingMarkerPayload);
+  profiler_add_marker(aMarkerName, aCategoryPair,
+                      TracingMarkerPayload(aCategoryString, aKind, aDocShellId,
+                                           aDocShellHistoryId));
 }
 
 void profiler_tracing(const char* aCategoryString, const char* aMarkerName,
@@ -4127,14 +4532,15 @@ void profiler_tracing(const char* aCategoryString, const char* aMarkerName,
   VTUNE_TRACING(aMarkerName, aKind);
 
   // This function is hot enough that we use RacyFeatures, notActivePS.
-  if (!RacyFeatures::IsActiveWithoutPrivacy()) {
+  if (!profiler_can_accept_markers()) {
     return;
   }
 
-  auto payload =
-      MakeUnique<TracingMarkerPayload>(aCategoryString, aKind, aDocShellId,
-                                       aDocShellHistoryId, std::move(aCause));
-  racy_profiler_add_marker(aMarkerName, aCategoryPair, std::move(payload));
+  AUTO_PROFILER_STATS(add_marker_with_TracingMarkerPayload);
+  profiler_add_marker(
+      aMarkerName, aCategoryPair,
+      TracingMarkerPayload(aCategoryString, aKind, aDocShellId,
+                           aDocShellHistoryId, std::move(aCause)));
 }
 
 void profiler_add_text_marker(
@@ -4144,10 +4550,11 @@ void profiler_add_text_marker(
     const mozilla::Maybe<nsID>& aDocShellId,
     const mozilla::Maybe<uint32_t>& aDocShellHistoryId,
     UniqueProfilerBacktrace aCause) {
+  AUTO_PROFILER_STATS(add_marker_with_TextMarkerPayload);
   profiler_add_marker(
       aMarkerName, aCategoryPair,
-      MakeUnique<TextMarkerPayload>(aText, aStartTime, aEndTime, aDocShellId,
-                                    aDocShellHistoryId, std::move(aCause)));
+      TextMarkerPayload(aText, aStartTime, aEndTime, aDocShellId,
+                        aDocShellHistoryId, std::move(aCause)));
 }
 
 void profiler_set_js_context(JSContext* aCx) {
@@ -4172,7 +4579,7 @@ void profiler_set_js_context(JSContext* aCx) {
         ActivePS::GetProfiledThreadData(lock, registeredThread);
     if (profiledThreadData) {
       profiledThreadData->NotifyReceivedJSContext(
-          ActivePS::Buffer(lock).mRangeEnd);
+          ActivePS::Buffer(lock).BufferRangeEnd());
     }
   }
 }
@@ -4243,8 +4650,10 @@ void profiler_suspend_and_sample_thread(int aThreadId, uint32_t aFeatures,
 
       // Suspend, sample, and then resume the target thread.
       Sampler sampler(lock);
+      TimeStamp now = TimeStamp::Now();
       sampler.SuspendAndSampleAndResumeThread(
-          lock, registeredThread, [&](const Registers& aRegs) {
+          lock, registeredThread, now,
+          [&](const Registers& aRegs, const TimeStamp& aNow) {
             // The target thread is now suspended. Collect a native backtrace,
             // and call the callback.
             bool isSynchronous = false;
@@ -4257,7 +4666,8 @@ void profiler_suspend_and_sample_thread(int aThreadId, uint32_t aFeatures,
               DoFramePointerBacktrace(lock, registeredThread, aRegs,
                                       nativeStack);
 #  elif defined(USE_MOZ_STACK_WALK)
-          DoMozStackWalkBacktrace(lock, registeredThread, aRegs, nativeStack);
+              DoMozStackWalkBacktrace(lock, registeredThread, aRegs,
+                                      nativeStack);
 #  else
 #    error "Invalid configuration"
 #  endif
diff --git a/tools/profiler/core/platform.h b/tools/profiler/core/platform.h
index afa940cd2b..92782ff6f3 100644
--- a/tools/profiler/core/platform.h
+++ b/tools/profiler/core/platform.h
@@ -41,6 +41,10 @@
 #include <functional>
 #include <stdint.h>
 
+namespace mozilla {
+struct SymbolTable;
+}
+
 extern mozilla::LazyLogModule gProfilerLog;
 
 // These are for MOZ_LOG="prof:3" or higher. It's the default logging level for
@@ -91,9 +95,8 @@ void profiler_get_profile_json_into_lazily_allocated_buffer(
 // Flags to conveniently track various JS instrumentations.
 enum class JSInstrumentationFlags {
   StackSampling = 0x1,
-  TrackOptimizations = 0x2,
-  TraceLogging = 0x4,
-  Allocations = 0x8
+  TraceLogging = 0x2,
+  Allocations = 0x4,
 };
 
 // Record an exit profile from a child process.
@@ -103,4 +106,20 @@ void profiler_received_exit_profile(const nsCString& aExitProfile);
 // still intersect with this process' buffer range).
 mozilla::Vector<nsCString> profiler_move_exit_profiles();
 
+// If the "MOZ_PROFILER_SYMBOLICATE" env-var is set, we return a new
+// ProfilerCodeAddressService object to use for local symbolication of profiles.
+// This is off by default, and mainly intended for local development.
+mozilla::UniquePtr<ProfilerCodeAddressService>
+profiler_code_address_service_for_presymbolication();
+
+extern "C" {
+// This function is defined in the profiler rust module at
+// tools/profiler/rust-helper. mozilla::SymbolTable and CompactSymbolTable
+// have identical memory layout.
+bool profiler_get_symbol_table(const char* debug_path, const char* breakpad_id,
+                               mozilla::SymbolTable* symbol_table);
+
+bool profiler_demangle_rust(const char* mangled, char* buffer, size_t len);
+}
+
 #endif /* ndef TOOLS_PLATFORM_H_ */
diff --git a/tools/profiler/gecko/ProfilerChild.cpp b/tools/profiler/gecko/ProfilerChild.cpp
index ec4b33b956..1bcd53666b 100644
--- a/tools/profiler/gecko/ProfilerChild.cpp
+++ b/tools/profiler/gecko/ProfilerChild.cpp
@@ -25,9 +25,9 @@ mozilla::ipc::IPCResult ProfilerChild::RecvStart(
     filterArray.AppendElement(params.filters()[i].get());
   }
 
-  profiler_start(params.entries(), params.interval(), params.features(),
-                 filterArray.Elements(), filterArray.Length(),
-                 params.duration());
+  profiler_start(PowerOfTwo32(params.entries()), params.interval(),
+                 params.features(), filterArray.Elements(),
+                 filterArray.Length(), params.duration());
 
   return IPC_OK();
 }
@@ -39,7 +39,7 @@ mozilla::ipc::IPCResult ProfilerChild::RecvEnsureStarted(
     filterArray.AppendElement(params.filters()[i].get());
   }
 
-  profiler_ensure_started(params.entries(), params.interval(),
+  profiler_ensure_started(PowerOfTwo32(params.entries()), params.interval(),
                           params.features(), filterArray.Elements(),
                           filterArray.Length(), params.duration());
 
diff --git a/tools/profiler/gecko/ProfilerIOInterposeObserver.cpp b/tools/profiler/gecko/ProfilerIOInterposeObserver.cpp
index f338c4d73b..5138d343a8 100644
--- a/tools/profiler/gecko/ProfilerIOInterposeObserver.cpp
+++ b/tools/profiler/gecko/ProfilerIOInterposeObserver.cpp
@@ -18,10 +18,9 @@ void ProfilerIOInterposeObserver::Observe(Observation& aObservation) {
 
   nsString filename;
   aObservation.Filename(filename);
-  profiler_add_marker(
-      "FileIO", JS::ProfilingCategoryPair::OTHER,
-      MakeUnique<FileIOMarkerPayload>(
-          aObservation.ObservedOperationString(), aObservation.Reference(),
-          NS_ConvertUTF16toUTF8(filename).get(), aObservation.Start(),
-          aObservation.End(), std::move(stack)));
+  PROFILER_ADD_MARKER_WITH_PAYLOAD(
+      "FileIO", OTHER, FileIOMarkerPayload,
+      (aObservation.ObservedOperationString(), aObservation.Reference(),
+       NS_ConvertUTF16toUTF8(filename).get(), aObservation.Start(),
+       aObservation.End(), std::move(stack)));
 }
diff --git a/tools/profiler/gecko/ThreadResponsiveness.cpp b/tools/profiler/gecko/ThreadResponsiveness.cpp
deleted file mode 100644
index eeed6d31b3..0000000000
--- a/tools/profiler/gecko/ThreadResponsiveness.cpp
+++ /dev/null
@@ -1,161 +0,0 @@
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-#include "ThreadResponsiveness.h"
-
-#include "platform.h"
-
-#include "mozilla/Atomics.h"
-#include "mozilla/SystemGroup.h"
-#include "nsITimer.h"
-
-using namespace mozilla;
-
-class CheckResponsivenessTask : public CancelableRunnable,
-                                public nsITimerCallback {
- public:
-  explicit CheckResponsivenessTask(nsIEventTarget* aThread, bool aIsMainThread)
-      : CancelableRunnable("CheckResponsivenessTask"),
-        mStartToPrevTracer_us(uint64_t(profiler_time() * 1000.0)),
-        mStop(false),
-        mHasEverBeenSuccessfullyDispatched(false),
-        mThread(aThread),
-        mIsMainThread(aIsMainThread) {}
-
- protected:
-  ~CheckResponsivenessTask() {}
-
- public:
-  // Must be called from the same thread every time. Call that the update
-  // thread, because it's the thread that ThreadResponsiveness::Update() is
-  // called on. In reality it's the profiler's sampler thread.
-  bool DoFirstDispatchIfNeeded() {
-    if (mHasEverBeenSuccessfullyDispatched) {
-      return true;
-    }
-
-    // The profiler for the main thread is set up before the thread manager is,
-    // meaning we can't get the nsIThread when the CheckResponsivenessTask is
-    // constructed. We _do_ know whether it is the main thread at that time,
-    // however, so here's the workaround. We can still hit this code before the
-    // thread manager is initted, in which case we won't try to record
-    // responsiveness, which is fine because there's no event queue to check
-    // responsiveness on anyway.
-    if (mIsMainThread) {
-      if (!mThread) {
-        nsCOMPtr<nsIThread> temp;
-        NS_GetMainThread(getter_AddRefs(temp));
-        mThread = temp.forget();
-      }
-
-      if (mThread) {
-        nsresult rv =
-            SystemGroup::Dispatch(TaskCategory::Other, do_AddRef(this));
-        if (NS_SUCCEEDED(rv)) {
-          mHasEverBeenSuccessfullyDispatched = true;
-        }
-      }
-    } else if (mThread) {
-      nsresult rv = mThread->Dispatch(this, nsIThread::NS_DISPATCH_NORMAL);
-      if (NS_SUCCEEDED(rv)) {
-        mHasEverBeenSuccessfullyDispatched = true;
-      }
-    }
-
-    return mHasEverBeenSuccessfullyDispatched;
-  }
-
-  nsresult Cancel() override {
-    // No special work needed.
-    return NS_OK;
-  }
-
-  // Only runs on the thread being profiled. Always called via a thread
-  // dispatch, so inherently functions as a responsiveness statistic.
-  NS_IMETHOD Run() override {
-    // This approach means that the 16ms delay in the timer below, _plus_ any
-    // additional delays in the TimerThread itself, become part of the
-    // responsiveness statistic for this thread. What we should probably be
-    // doing is recording responsiveness only when we have dispatched (but not
-    // executed) a call to this function, either because of a call to
-    // DoFirstDispatchIfNeeded, or a call to Notify.
-    mStartToPrevTracer_us = uint64_t(profiler_time() * 1000.0);
-
-    if (!mStop) {
-      if (!mTimer) {
-        if (mIsMainThread) {
-          mTimer =
-              NS_NewTimer(SystemGroup::EventTargetFor(TaskCategory::Other));
-        } else {
-          mTimer = NS_NewTimer();
-        }
-      }
-      mTimer->InitWithCallback(this, 16, nsITimer::TYPE_ONE_SHOT);
-    }
-
-    return NS_OK;
-  }
-
-  // Should always fire on the thread being profiled
-  NS_IMETHOD Notify(nsITimer* aTimer) final {
-    Run();
-    return NS_OK;
-  }
-
-  // Can be called on any thread.
-  void Terminate() { mStop = true; }
-
-  // Can be called on any thread.
-  double GetStartToPrevTracer_ms() const {
-    return mStartToPrevTracer_us / 1000.0;
-  }
-
-  NS_DECL_ISUPPORTS_INHERITED
-
- private:
-  // The timer that's responsible for redispatching this event to the thread we
-  // are profiling (ie; mThread). Only touched on mThread.
-  nsCOMPtr<nsITimer> mTimer;
-
-  // The time (in integer microseconds since process startup) at which this
-  // event was last processed (Run() was last called).
-  // This field is written on mThread and read on the update thread.
-  // This is stored as integer microseconds instead of double milliseconds
-  // because Atomic<double> is not available.
-  Atomic<uint64_t> mStartToPrevTracer_us;
-
-  // Whether we should stop redispatching this event once the timer fires the
-  // next time. Set to true by any thread when the profiler is stopped; read on
-  // mThread.
-  Atomic<bool> mStop;
-
-  // Only accessed on the update thread.
-  bool mHasEverBeenSuccessfullyDispatched;
-
-  // The thread that we're profiling. Use nsIEventTarget to allow for checking
-  // responsiveness on non-nsIThreads someday.
-  nsCOMPtr<nsIEventTarget> mThread;
-  bool mIsMainThread;
-};
-
-NS_IMPL_ISUPPORTS_INHERITED(CheckResponsivenessTask, CancelableRunnable,
-                            nsITimerCallback)
-
-ThreadResponsiveness::ThreadResponsiveness(nsIEventTarget* aThread,
-                                           bool aIsMainThread)
-    : mActiveTracerEvent(new CheckResponsivenessTask(aThread, aIsMainThread)) {
-  MOZ_COUNT_CTOR(ThreadResponsiveness);
-}
-
-ThreadResponsiveness::~ThreadResponsiveness() {
-  MOZ_COUNT_DTOR(ThreadResponsiveness);
-  mActiveTracerEvent->Terminate();
-}
-
-void ThreadResponsiveness::Update() {
-  if (!mActiveTracerEvent->DoFirstDispatchIfNeeded()) {
-    return;
-  }
-  mStartToPrevTracer_ms = Some(mActiveTracerEvent->GetStartToPrevTracer_ms());
-}
diff --git a/tools/profiler/gecko/ThreadResponsiveness.h b/tools/profiler/gecko/ThreadResponsiveness.h
deleted file mode 100644
index 8a98b87bd0..0000000000
--- a/tools/profiler/gecko/ThreadResponsiveness.h
+++ /dev/null
@@ -1,40 +0,0 @@
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-#ifndef ThreadResponsiveness_h
-#define ThreadResponsiveness_h
-
-#include "mozilla/Maybe.h"
-#include "mozilla/RefPtr.h"
-#include "mozilla/TimeStamp.h"
-#include "nsISupports.h"
-
-class CheckResponsivenessTask;
-class nsIEventTarget;
-
-// This class should only be used for the main thread.
-class ThreadResponsiveness {
- public:
-  explicit ThreadResponsiveness(nsIEventTarget* aThread, bool aIsMainThread);
-
-  ~ThreadResponsiveness();
-
-  void Update();
-
-  // The number of milliseconds that elapsed since the last
-  // CheckResponsivenessTask was processed.
-  double GetUnresponsiveDuration(double aStartToNow_ms) const {
-    return aStartToNow_ms - *mStartToPrevTracer_ms;
-  }
-
-  bool HasData() const { return mStartToPrevTracer_ms.isSome(); }
-
- private:
-  RefPtr<CheckResponsivenessTask> mActiveTracerEvent;
-  // The time at which the last CheckResponsivenessTask was processed, in
-  // milliseconds since process start (i.e. what you get from profiler_time()).
-  mozilla::Maybe<double> mStartToPrevTracer_ms;
-};
-
-#endif
diff --git a/tools/profiler/gecko/components.conf b/tools/profiler/gecko/components.conf
index 66b0f25313..a347642b12 100644
--- a/tools/profiler/gecko/components.conf
+++ b/tools/profiler/gecko/components.conf
@@ -4,8 +4,10 @@
 
 Classes = [
     {
+        'js_name': 'profiler',
         'cid': '{25db9b8e-8123-4de1-b66d-8bbbedf2cdf4}',
         'contract_ids': ['@mozilla.org/tools/profiler;1'],
+        'interfaces': ['nsIProfiler'],
         'type': 'nsProfiler',
         'headers': ['/tools/profiler/gecko/nsProfiler.h'],
         'init_method': 'Init',
diff --git a/tools/profiler/gecko/nsIProfiler.idl b/tools/profiler/gecko/nsIProfiler.idl
index dd37325d2a..d83bc387b1 100644
--- a/tools/profiler/gecko/nsIProfiler.idl
+++ b/tools/profiler/gecko/nsIProfiler.idl
@@ -34,11 +34,9 @@ interface nsIProfiler : nsISupports
 {
   boolean CanProfile();
   void StartProfiler(in uint32_t aEntries, in double aInterval,
-                      [array, size_is(aFeatureCount)] in string aFeatures,
-                      in uint32_t aFeatureCount,
-                      [array, size_is(aFilterCount), optional] in string aFilters,
-                      [optional] in uint32_t aFilterCount,
-                      [optional] in double aDuration);
+                     in Array<AUTF8String> aFeatures,
+                     [optional] in Array<AUTF8String> aFilters,
+                     [optional] in double aDuration);
   void StopProfiler();
   boolean IsPaused();
   void PauseSampling();
@@ -84,13 +82,13 @@ interface nsIProfiler : nsISupports
    * Returns an array of the features that are supported in this build.
    * Features may vary depending on platform and build flags.
    */
-  void GetFeatures(out uint32_t aCount, [retval, array, size_is(aCount)] out string aFeatures);
+  Array<AUTF8String> GetFeatures();
 
   /**
    * Returns an array of all features that are supported by the profiler.
    * The array may contain features that are not supported in this build.
    */
-  void GetAllFeatures(out uint32_t aCount, [retval, array, size_is(aCount)] out string aFeatures);
+  Array<AUTF8String> GetAllFeatures();
 
   void GetBufferInfo(out uint32_t aCurrentPosition, out uint32_t aTotalSize,
                      out uint32_t aGeneration);
diff --git a/tools/profiler/gecko/nsProfiler.cpp b/tools/profiler/gecko/nsProfiler.cpp
index c0cbf91666..84a1251ee0 100644
--- a/tools/profiler/gecko/nsProfiler.cpp
+++ b/tools/profiler/gecko/nsProfiler.cpp
@@ -40,14 +40,6 @@ using dom::AutoJSAPI;
 using dom::Promise;
 using std::string;
 
-extern "C" {
-// This function is defined in the profiler rust module at
-// tools/profiler/rust-helper. nsProfiler::SymbolTable and CompactSymbolTable
-// have identical memory layout.
-bool profiler_get_symbol_table(const char* debug_path, const char* breakpad_id,
-                               nsProfiler::SymbolTable* symbol_table);
-}
-
 NS_IMPL_ISUPPORTS(nsProfiler, nsIProfiler, nsIObserver)
 
 nsProfiler::nsProfiler()
@@ -104,10 +96,21 @@ nsProfiler::CanProfile(bool* aCanProfile) {
   return NS_OK;
 }
 
+static nsresult FillVectorFromStringArray(Vector<const char*>& aVector,
+                                          const nsTArray<nsCString>& aArray) {
+  if (NS_WARN_IF(!aVector.reserve(aArray.Length()))) {
+    return NS_ERROR_OUT_OF_MEMORY;
+  }
+  for (auto& entry : aArray) {
+    aVector.infallibleAppend(entry.get());
+  }
+  return NS_OK;
+}
+
 NS_IMETHODIMP
 nsProfiler::StartProfiler(uint32_t aEntries, double aInterval,
-                          const char** aFeatures, uint32_t aFeatureCount,
-                          const char** aFilters, uint32_t aFilterCount,
+                          const nsTArray<nsCString>& aFeatures,
+                          const nsTArray<nsCString>& aFilters,
                           double aDuration) {
   if (mLockedForPrivateBrowsing) {
     return NS_ERROR_NOT_AVAILABLE;
@@ -115,9 +118,22 @@ nsProfiler::StartProfiler(uint32_t aEntries, double aInterval,
 
   ResetGathering();
 
-  uint32_t features = ParseFeaturesFromStringArray(aFeatures, aFeatureCount);
+  Vector<const char*> featureStringVector;
+  nsresult rv = FillVectorFromStringArray(featureStringVector, aFeatures);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+  uint32_t features = ParseFeaturesFromStringArray(
+      featureStringVector.begin(), featureStringVector.length());
   Maybe<double> duration = aDuration > 0.0 ? Some(aDuration) : Nothing();
-  profiler_start(aEntries, aInterval, features, aFilters, aFilterCount,
+
+  Vector<const char*> filterStringVector;
+  rv = FillVectorFromStringArray(filterStringVector, aFilters);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+  profiler_start(PowerOfTwo32(aEntries), aInterval, features,
+                 filterStringVector.begin(), filterStringVector.length(),
                  duration);
 
   return NS_OK;
@@ -156,7 +172,7 @@ nsProfiler::ResumeSampling() {
 
 NS_IMETHODIMP
 nsProfiler::AddMarker(const char* aMarker) {
-  profiler_add_marker(aMarker, JS::ProfilingCategoryPair::OTHER);
+  PROFILER_ADD_MARKER(aMarker, OTHER);
   return NS_OK;
 }
 
@@ -570,8 +586,8 @@ nsProfiler::IsActive(bool* aIsActive) {
   return NS_OK;
 }
 
-static void GetArrayOfStringsForFeatures(uint32_t aFeatures, uint32_t* aCount,
-                                         char*** aFeatureList) {
+static void GetArrayOfStringsForFeatures(uint32_t aFeatures,
+                                         nsTArray<nsCString>& aFeatureList) {
 #define COUNT_IF_SET(n_, str_, Name_, desc_)    \
   if (ProfilerFeature::Has##Name_(aFeatures)) { \
     len++;                                      \
@@ -583,34 +599,29 @@ static void GetArrayOfStringsForFeatures(uint32_t aFeatures, uint32_t* aCount,
 
 #undef COUNT_IF_SET
 
-  auto featureList = static_cast<char**>(moz_xmalloc(len * sizeof(char*)));
+  aFeatureList.SetCapacity(len);
 
 #define DUP_IF_SET(n_, str_, Name_, desc_)      \
   if (ProfilerFeature::Has##Name_(aFeatures)) { \
-    featureList[i] = moz_xstrdup(str_);         \
-    i++;                                        \
+    aFeatureList.AppendElement(str_);           \
   }
 
   // Insert the strings for the features in use.
-  size_t i = 0;
   PROFILER_FOR_EACH_FEATURE(DUP_IF_SET)
 
 #undef DUP_IF_SET
-
-  *aFeatureList = featureList;
-  *aCount = len;
 }
 
 NS_IMETHODIMP
-nsProfiler::GetFeatures(uint32_t* aCount, char*** aFeatureList) {
+nsProfiler::GetFeatures(nsTArray<nsCString>& aFeatureList) {
   uint32_t features = profiler_get_available_features();
-  GetArrayOfStringsForFeatures(features, aCount, aFeatureList);
+  GetArrayOfStringsForFeatures(features, aFeatureList);
   return NS_OK;
 }
 
 NS_IMETHODIMP
-nsProfiler::GetAllFeatures(uint32_t* aCount, char*** aFeatureList) {
-  GetArrayOfStringsForFeatures((uint32_t)-1, aCount, aFeatureList);
+nsProfiler::GetAllFeatures(nsTArray<nsCString>& aFeatureList) {
+  GetArrayOfStringsForFeatures((uint32_t)-1, aFeatureList);
   return NS_OK;
 }
 
@@ -691,10 +702,14 @@ RefPtr<nsProfiler::GatheringPromise> nsProfiler::StartGathering(
 
   mWriter.emplace();
 
+  UniquePtr<ProfilerCodeAddressService> service =
+      profiler_code_address_service_for_presymbolication();
+
   // Start building up the JSON result and grab the profile from this process.
   mWriter->Start();
   if (!profiler_stream_json_for_this_process(*mWriter, aSinceTime,
-                                             /* aIsShuttingDown */ false)) {
+                                             /* aIsShuttingDown */ false,
+                                             service.get())) {
     // The profiler is inactive. This either means that it was inactive even
     // at the time that ProfileGatherer::Start() was called, or that it was
     // stopped on a different thread since that call. Either way, we need to
diff --git a/tools/profiler/gecko/nsProfiler.h b/tools/profiler/gecko/nsProfiler.h
index d388d4abce..209d3ecf1a 100644
--- a/tools/profiler/gecko/nsProfiler.h
+++ b/tools/profiler/gecko/nsProfiler.h
@@ -14,6 +14,7 @@
 #include "mozilla/Vector.h"
 #include "nsServiceManagerUtils.h"
 #include "ProfileJSONWriter.h"
+#include "ProfilerCodeAddressService.h"
 
 class nsProfiler final : public nsIProfiler, public nsIObserver {
  public:
@@ -33,24 +34,12 @@ class nsProfiler final : public nsIProfiler, public nsIObserver {
 
   void GatheredOOPProfile(const nsACString& aProfile);
 
-  // This SymbolTable struct, and the CompactSymbolTable struct in the
-  // profiler rust module, have the exact same memory layout.
-  // nsTArray and ThinVec are FFI-compatible, because the thin-vec crate is
-  // being compiled with the "gecko-ffi" feature enabled.
-  struct SymbolTable {
-    SymbolTable() = default;
-    SymbolTable(SymbolTable&& aOther) = default;
-
-    nsTArray<uint32_t> mAddrs;
-    nsTArray<uint32_t> mIndex;
-    nsTArray<uint8_t> mBuffer;
-  };
-
  private:
   ~nsProfiler();
 
   typedef mozilla::MozPromise<nsCString, nsresult, false> GatheringPromise;
-  typedef mozilla::MozPromise<SymbolTable, nsresult, true> SymbolTablePromise;
+  typedef mozilla::MozPromise<mozilla::SymbolTable, nsresult, true>
+      SymbolTablePromise;
 
   RefPtr<GatheringPromise> StartGathering(double aSinceTime);
   void FinishGathering();
diff --git a/tools/profiler/moz.build b/tools/profiler/moz.build
index fa37685a66..52a1c284df 100644
--- a/tools/profiler/moz.build
+++ b/tools/profiler/moz.build
@@ -13,6 +13,7 @@ if CONFIG['MOZ_GECKO_PROFILER']:
         'public/GeckoProfilerReporter.h',
         'public/ProfileJSONWriter.h',
         'public/ProfilerChild.h',
+        'public/ProfilerCodeAddressService.h',
         'public/ProfilerMarkerPayload.h',
         'public/ProfilerParent.h',
         'public/shared-libraries.h',
@@ -25,14 +26,14 @@ if CONFIG['MOZ_GECKO_PROFILER']:
         'core/ProfiledThreadData.cpp',
         'core/ProfileJSONWriter.cpp',
         'core/ProfilerBacktrace.cpp',
+        'core/ProfilerCodeAddressService.cpp',
         'core/ProfilerMarkerPayload.cpp',
         'core/RegisteredThread.cpp',
         'gecko/ChildProfilerController.cpp',
         'gecko/nsProfilerStartParams.cpp',
         'gecko/ProfilerChild.cpp',
-        #'gecko/ProfilerIOInterposeObserver.cpp',
+        'gecko/ProfilerIOInterposeObserver.cpp',
         'gecko/ProfilerParent.cpp',
-        'gecko/ThreadResponsiveness.cpp',
     ]
     if CONFIG['MOZ_REPLACE_MALLOC'] and CONFIG['MOZ_PROFILER_MEMORY']:
         SOURCES += [
@@ -135,8 +136,9 @@ EXPORTS += [
     'public/GeckoProfiler.h',
 ]
 
-# vm/GeckoProfiler.h needs to include this and doesn't like #include "ProfilerCounts.h"
 EXPORTS.mozilla += [
+    'public/BlocksRingBufferGeckoExtensions.h',
+    # vm/GeckoProfiler.h needs to include this and doesn't like #include "ProfilerCounts.h"
     'public/ProfilerCounts.h',
 ]
 
diff --git a/tools/profiler/public/BlocksRingBufferGeckoExtensions.h b/tools/profiler/public/BlocksRingBufferGeckoExtensions.h
new file mode 100644
index 0000000000..a0cd5a2762
--- /dev/null
+++ b/tools/profiler/public/BlocksRingBufferGeckoExtensions.h
@@ -0,0 +1,155 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef BlocksRingBufferGeckoExtensions_h
+#define BlocksRingBufferGeckoExtensions_h
+
+#include "mozilla/BlocksRingBuffer.h"
+
+#include "js/AllocPolicy.h"
+#include "js/Utility.h"
+#include "nsString.h"
+
+namespace mozilla {
+
+// ----------------------------------------------------------------------------
+// ns[C]String
+
+// nsString or nsCString contents are serialized as the number of bytes (encoded
+// as ULEB128) and all the characters in the string. The terminal '\0' is
+// omitted.
+// Make sure you write and read with the same character type!
+//
+// Usage: `nsCString s = ...; aEW.WriteObject(s);`
+template <typename T>
+struct BlocksRingBuffer::Serializer<nsTString<T>> {
+  static Length Bytes(const nsTString<T>& aS) {
+    // Note that we store the size in *bytes*, not in number of characters.
+    const auto bytes = aS.Length() * sizeof(T);
+    return EntryWriter::ULEB128Size(bytes) + static_cast<Length>(bytes);
+  }
+
+  static void Write(EntryWriter& aEW, const nsTString<T>& aS) {
+    // Note that we store the size in *bytes*, not in number of characters.
+    const auto bytes = aS.Length() * sizeof(T);
+    aEW.WriteULEB128(bytes);
+    // Copy the bytes from the string's buffer.
+    aEW.Write(reinterpret_cast<const char*>(aS.BeginReading()), bytes);
+  }
+};
+
+template <typename T>
+struct BlocksRingBuffer::Deserializer<nsTString<T>> {
+  static void ReadInto(EntryReader& aER, nsTString<T>& aS) { aS = Read(aER); }
+
+  static nsTString<T> Read(EntryReader& aER) {
+    // Note that the stored size is in *bytes*, not in number of characters.
+    const auto bytes = aER.ReadULEB128<Length>();
+    nsTString<T> s;
+    nsresult rv;
+    // BulkWrite is the most efficient way to copy bytes into the target string.
+    auto writer = s.BulkWrite(bytes / sizeof(T), 0, true, rv);
+    MOZ_RELEASE_ASSERT(NS_SUCCEEDED(rv));
+    aER.Read(reinterpret_cast<char*>(writer.Elements()), bytes);
+    writer.Finish(bytes / sizeof(T), true);
+    return s;
+  }
+};
+
+// ----------------------------------------------------------------------------
+// nsAuto[C]String
+
+// nsAuto[C]String contents are serialized as the number of bytes (encoded as
+// ULEB128) and all the characters in the string. The terminal '\0' is omitted.
+// Make sure you write and read with the same character type!
+//
+// Usage: `nsAutoCString s = ...; aEW.WriteObject(s);`
+template <typename T, size_t N>
+struct BlocksRingBuffer::Serializer<nsTAutoStringN<T, N>> {
+  static Length Bytes(const nsTAutoStringN<T, N>& aS) {
+    // Note that we store the size in *bytes*, not in number of characters.
+    const auto bytes = aS.Length() * sizeof(T);
+    return EntryWriter::ULEB128Size(bytes) + static_cast<Length>(bytes);
+  }
+
+  static void Write(EntryWriter& aEW, const nsTAutoStringN<T, N>& aS) {
+    const auto bytes = aS.Length() * sizeof(T);
+    // Note that we store the size in *bytes*, not in number of characters.
+    aEW.WriteULEB128(bytes);
+    // Copy the bytes from the string's buffer.
+    aEW.Write(reinterpret_cast<const char*>(aS.BeginReading()), bytes);
+  }
+};
+
+template <typename T, size_t N>
+struct BlocksRingBuffer::Deserializer<nsTAutoStringN<T, N>> {
+  static void ReadInto(EntryReader& aER, nsTAutoStringN<T, N>& aS) {
+    aS = Read(aER);
+  }
+
+  static nsTAutoStringN<T, N> Read(EntryReader& aER) {
+    // Note that the stored size is in *bytes*, not in number of characters.
+    const auto bytes = aER.ReadULEB128<Length>();
+    nsTAutoStringN<T, N> s;
+    nsresult rv;
+    // BulkWrite is the most efficient way to copy bytes into the target string.
+    auto writer = s.BulkWrite(bytes / sizeof(T), 0, true, rv);
+    MOZ_RELEASE_ASSERT(NS_SUCCEEDED(rv));
+    aER.Read(reinterpret_cast<char*>(writer.Elements()), bytes);
+    writer.Finish(bytes / sizeof(T), true);
+    return s;
+  }
+};
+
+// ----------------------------------------------------------------------------
+// JS::UniqueChars
+
+// JS::UniqueChars contents are serialized as the number of bytes (encoded as
+// ULEB128) and all the characters in the string. The terminal '\0' is omitted.
+// Note: A nullptr pointer will be serialized like an empty string, so when
+// deserializing it will result in an allocated buffer only containing a
+// single null terminator.
+//
+// Usage: `JS::UniqueChars s = ...; aEW.WriteObject(s);`
+template <>
+struct BlocksRingBuffer::Serializer<JS::UniqueChars> {
+  static Length Bytes(const JS::UniqueChars& aS) {
+    if (!aS) {
+      return EntryWriter::ULEB128Size<Length>(0);
+    }
+    const auto len = static_cast<Length>(strlen(aS.get()));
+    return EntryWriter::ULEB128Size(len) + len;
+  }
+
+  static void Write(EntryWriter& aEW, const JS::UniqueChars& aS) {
+    if (!aS) {
+      aEW.WriteULEB128<Length>(0);
+      return;
+    }
+    const auto len = static_cast<Length>(strlen(aS.get()));
+    aEW.WriteULEB128(len);
+    aEW.Write(aS.get(), len);
+  }
+};
+
+template <>
+struct BlocksRingBuffer::Deserializer<JS::UniqueChars> {
+  static void ReadInto(EntryReader& aER, JS::UniqueChars& aS) {
+    aS = Read(aER);
+  }
+
+  static JS::UniqueChars Read(EntryReader& aER) {
+    const auto len = aER.ReadULEB128<Length>();
+    // Use the same allocation policy as JS_smprintf.
+    char* buffer =
+        static_cast<char*>(js::SystemAllocPolicy{}.pod_malloc<char>(len + 1));
+    aER.Read(buffer, len);
+    buffer[len] = '\0';
+    return JS::UniqueChars(buffer);
+  }
+};
+
+}  // namespace mozilla
+
+#endif  // BlocksRingBufferGeckoExtensions_h
diff --git a/tools/profiler/public/GeckoProfiler.h b/tools/profiler/public/GeckoProfiler.h
index f5396835a0..9a90b2c38e 100644
--- a/tools/profiler/public/GeckoProfiler.h
+++ b/tools/profiler/public/GeckoProfiler.h
@@ -26,6 +26,7 @@
 // avoid the need for many #ifdefs.
 
 #  define AUTO_PROFILER_INIT
+#  define AUTO_PROFILER_INIT2
 
 #  define PROFILER_REGISTER_THREAD(name)
 #  define PROFILER_UNREGISTER_THREAD()
@@ -49,6 +50,8 @@
                                            ctx, flags)
 
 #  define PROFILER_ADD_MARKER(markerName, categoryPair)
+#  define PROFILER_ADD_MARKER_WITH_PAYLOAD(markerName, categoryPair, \
+                                           PayloadType, payloadArgs)
 #  define PROFILER_ADD_NETWORK_MARKER(uri, pri, channel, type, start, end, \
                                       count, cache, timings, redirect)
 
@@ -67,6 +70,7 @@
 
 #else  // !MOZ_GECKO_PROFILER
 
+#  include "BaseProfiler.h"
 #  include "js/AllocationRecording.h"
 #  include "js/ProfilingFrameIterator.h"
 #  include "js/ProfilingStack.h"
@@ -77,6 +81,7 @@
 #  include "mozilla/Attributes.h"
 #  include "mozilla/GuardObjects.h"
 #  include "mozilla/Maybe.h"
+#  include "mozilla/PowerOfTwo.h"
 #  include "mozilla/Sprintf.h"
 #  include "mozilla/ThreadLocal.h"
 #  include "mozilla/TimeStamp.h"
@@ -89,6 +94,7 @@
 #  include <stdint.h>
 
 class ProfilerBacktrace;
+class ProfilerCodeAddressService;
 class ProfilerMarkerPayload;
 class SpliceableJSONWriter;
 namespace mozilla {
@@ -131,35 +137,35 @@ class Vector;
     MACRO(3, "mainthreadio", MainThreadIO,                                     \
           "Add main thread I/O to the profile")                                \
                                                                                \
-    MACRO(4, "memory", Memory, "Add memory measurements")                      \
-                                                                               \
-    MACRO(5, "privacy", Privacy,                                               \
+    MACRO(4, "privacy", Privacy,                                               \
           "Do not include user-identifiable information")                      \
                                                                                \
-    MACRO(6, "responsiveness", Responsiveness,                                 \
-          "Collect thread responsiveness information")                         \
-                                                                               \
-    MACRO(7, "screenshots", Screenshots,                                       \
+    MACRO(5, "screenshots", Screenshots,                                       \
           "Take a snapshot of the window on every composition")                \
                                                                                \
-    MACRO(8, "seqstyle", SequentialStyle,                                      \
+    MACRO(6, "seqstyle", SequentialStyle,                                      \
           "Disable parallel traversal in styling")                             \
                                                                                \
-    MACRO(9, "stackwalk", StackWalk,                                           \
+    MACRO(7, "stackwalk", StackWalk,                                           \
           "Walk the C++ stack, not available on all platforms")                \
                                                                                \
-    MACRO(10, "tasktracer", TaskTracer,                                        \
+    MACRO(8, "tasktracer", TaskTracer,                                         \
           "Start profiling with feature TaskTracer")                           \
                                                                                \
-    MACRO(11, "threads", Threads, "Profile the registered secondary threads")  \
+    MACRO(9, "threads", Threads, "Profile the registered secondary threads")   \
                                                                                \
-    MACRO(12, "trackopts", TrackOptimizations,                                 \
-          "Have the JavaScript engine track JIT optimizations")                \
+    MACRO(10, "jstracer", JSTracer, "Enable tracing of the JavaScript engine") \
                                                                                \
-    MACRO(13, "jstracer", JSTracer, "Enable tracing of the JavaScript engine") \
+    MACRO(11, "jsallocations", JSAllocations,                                  \
+          "Have the JavaScript engine track allocations")                      \
                                                                                \
-    MACRO(14, "jsallocations", JSAllocations,                                  \
-          "Have the JavaScript engine track allocations")
+    MACRO(14, "nostacksampling", NoStackSampling,                              \
+          "Disable all stack sampling: Cancels \"js\", \"leaf\", "             \
+          "\"stackwalk\" and labels")                                          \
+                                                                               \
+    MACRO(16, "nativeallocations", NativeAllocations,                          \
+          "Collect the stacks from a smaller subset of all native "            \
+          "allocations, biasing towards collecting larger allocations")
 
 struct ProfilerFeature {
 #  define DECLARE(n_, str_, Name_, desc_)                     \
@@ -200,6 +206,10 @@ class RacyFeatures {
 
   static void SetInactive() { sActiveAndFeatures = 0; }
 
+  static void SetPaused() { sActiveAndFeatures |= Paused; }
+
+  static void SetUnpaused() { sActiveAndFeatures &= ~Paused; }
+
   static bool IsActive() { return uint32_t(sActiveAndFeatures) & Active; }
 
   static bool IsActiveWithFeature(uint32_t aFeature) {
@@ -212,12 +222,18 @@ class RacyFeatures {
     return (af & Active) && !(af & ProfilerFeature::Privacy);
   }
 
- private:
-  static const uint32_t Active = 1u << 31;
+  static bool IsActiveAndUnpausedWithoutPrivacy() {
+    uint32_t af = sActiveAndFeatures;  // copy it first
+    return (af & Active) && !(af & (Paused | ProfilerFeature::Privacy));
+  }
 
-// Ensure Active doesn't overlap with any of the feature bits.
+ private:
+  static constexpr uint32_t Active = 1u << 31;
+  static constexpr uint32_t Paused = 1u << 30;
+
+// Ensure Active/Paused don't overlap with any of the feature bits.
 #  define NO_OVERLAP(n_, str_, Name_, desc_) \
-    static_assert(ProfilerFeature::Name_ != Active, "bad Active value");
+    static_assert(ProfilerFeature::Name_ != Paused, "bad feature value");
 
   PROFILER_FOR_EACH_FEATURE(NO_OVERLAP);
 
@@ -240,32 +256,37 @@ bool IsThreadBeingProfiled();
 // Start and stop the profiler
 //---------------------------------------------------------------------------
 
-static constexpr uint32_t PROFILER_DEFAULT_ENTRIES =
+static constexpr mozilla::PowerOfTwo32 PROFILER_DEFAULT_ENTRIES =
 #  if !defined(ARCH_ARMV6)
-    1u << 20;  // 1'048'576
+    mozilla::MakePowerOfTwo32<1u << 20>();  // 1'048'576 entries = 8MB
 #  else
-    1u << 17;  // 131'072
+    mozilla::MakePowerOfTwo32<1u << 17>();  // 131'072 entries = 1MB
 #  endif
 
 // Startup profiling usually need to capture more data, especially on slow
 // systems.
-static constexpr uint32_t PROFILER_DEFAULT_STARTUP_ENTRIES =
+static constexpr mozilla::PowerOfTwo32 PROFILER_DEFAULT_STARTUP_ENTRIES =
 #  if !defined(ARCH_ARMV6)
-    1u << 22;  // 4'194'304
+    mozilla::MakePowerOfTwo32<1u << 22>();  // 4'194'304 entries = 32MB
 #  else
-    1u << 17;  // 131'072
+    mozilla::MakePowerOfTwo32<1u << 17>();  // 131'072 entries = 1MB
 #  endif
 
-#  define PROFILER_DEFAULT_DURATION 20
-#  define PROFILER_DEFAULT_INTERVAL 1
+#  define PROFILER_DEFAULT_DURATION 20 /* seconds, for tests only */
+#  define PROFILER_DEFAULT_INTERVAL 1  /* millisecond */
+#  define PROFILER_MAX_INTERVAL 5000   /* milliseconds */
 
 // Initialize the profiler. If MOZ_PROFILER_STARTUP is set the profiler will
 // also be started. This call must happen before any other profiler calls
 // (except profiler_start(), which will call profiler_init() if it hasn't
 // already run).
 void profiler_init(void* stackTop);
+void profiler_init_threadmanager();
 
+// Call this as early as possible
 #  define AUTO_PROFILER_INIT mozilla::AutoProfilerInit PROFILER_RAII
+// Call this after the nsThreadManager is Init()ed
+#  define AUTO_PROFILER_INIT2 mozilla::AutoProfilerInit2 PROFILER_RAII
 
 // Clean up the profiler module, stopping it if required. This function may
 // also save a shutdown profile if requested. No profiler calls should happen
@@ -276,8 +297,8 @@ void profiler_shutdown();
 // selected options. Stops and restarts the profiler if it is already active.
 // After starting the profiler is "active". The samples will be recorded in a
 // circular buffer.
-//   "aCapacity" is the maximum number of entries in the profiler's circular
-//               buffer.
+//   "aCapacity" is the maximum number of 8-bytes entries in the profiler's
+//               circular buffer.
 //   "aInterval" the sampling interval, measured in millseconds.
 //   "aFeatures" is the feature set. Features unsupported by this
 //               platform/configuration are ignored.
@@ -289,7 +310,7 @@ void profiler_shutdown();
 //                  id of the process that the thread is running in.
 //   "aDuration" is the duration of entries in the profiler's circular buffer.
 void profiler_start(
-    uint32_t aCapacity, double aInterval, uint32_t aFeatures,
+    mozilla::PowerOfTwo32 aCapacity, double aInterval, uint32_t aFeatures,
     const char** aFilters, uint32_t aFilterCount,
     const mozilla::Maybe<double>& aDuration = mozilla::Nothing());
 
@@ -303,7 +324,7 @@ void profiler_stop();
 // The only difference to profiler_start is that the current buffer contents are
 // not discarded if the profiler is already running with the requested settings.
 void profiler_ensure_started(
-    uint32_t aCapacity, double aInterval, uint32_t aFeatures,
+    mozilla::PowerOfTwo32 aCapacity, double aInterval, uint32_t aFeatures,
     const char** aFilters, uint32_t aFilterCount,
     const mozilla::Maybe<double>& aDuration = mozilla::Nothing());
 
@@ -416,6 +437,19 @@ inline bool profiler_is_active() {
   return mozilla::profiler::detail::RacyFeatures::IsActive();
 }
 
+// Same as profiler_is_active(), but with the same extra checks that determine
+// if the profiler would currently store markers. So this should be used before
+// doing some potentially-expensive work that's used in a marker. E.g.:
+//
+//   if (profiler_can_accept_markers()) {
+//     ExpensiveMarkerPayload expensivePayload = CreateExpensivePayload();
+//     BASE_PROFILER_ADD_MARKER_WITH_PAYLOAD(name, OTHER, expensivePayload);
+//   }
+inline bool profiler_can_accept_markers() {
+  return mozilla::profiler::detail::RacyFeatures::
+      IsActiveAndUnpausedWithoutPrivacy();
+}
+
 // Is the profiler active, and is the current thread being profiled?
 // (Same caveats and recommented usage as profiler_is_active().)
 inline bool profiler_thread_is_being_profiled() {
@@ -511,10 +545,42 @@ using UniqueProfilerBacktrace =
 // if the profiler is inactive or in privacy mode.
 UniqueProfilerBacktrace profiler_get_backtrace();
 
+struct ProfilerStats {
+  unsigned n = 0;
+  double sum = 0;
+  double min = std::numeric_limits<double>::max();
+  double max = 0;
+  void Count(double v) {
+    ++n;
+    sum += v;
+    if (v < min) {
+      min = v;
+    }
+    if (v > max) {
+      max = v;
+    }
+  }
+};
+
 struct ProfilerBufferInfo {
+  // Index of the oldest entry.
   uint64_t mRangeStart;
+  // Index of the newest entry.
   uint64_t mRangeEnd;
+  // Buffer capacity in number of 8-byte entries.
   uint32_t mEntryCount;
+  // Sampling stats: Interval between successive samplings.
+  ProfilerStats mIntervalsNs;
+  // Sampling stats: Total sampling duration. (Split detail below.)
+  ProfilerStats mOverheadsNs;
+  // Sampling stats: Time to acquire the lock before sampling.
+  ProfilerStats mLockingsNs;
+  // Sampling stats: Time to discard expired data.
+  ProfilerStats mCleaningsNs;
+  // Sampling stats: Time to collect counter data.
+  ProfilerStats mCountersNs;
+  // Sampling stats: Time to sample thread stacks.
+  ProfilerStats mThreadsNs;
 };
 
 // Get information about the current buffer status.
@@ -637,16 +703,37 @@ mozilla::Maybe<ProfilerBufferInfo> profiler_get_buffer_info();
 // certain length of time. A no-op if the profiler is inactive or in privacy
 // mode.
 
-#  define PROFILER_ADD_MARKER(markerName, categoryPair) \
-    profiler_add_marker(markerName, JS::ProfilingCategoryPair::categoryPair)
+#  define PROFILER_ADD_MARKER(markerName, categoryPair)                 \
+    do {                                                                \
+      AUTO_PROFILER_STATS(add_marker);                                  \
+      ::profiler_add_marker(markerName,                                 \
+                            ::JS::ProfilingCategoryPair::categoryPair); \
+    } while (false)
 
 void profiler_add_marker(const char* aMarkerName,
                          JS::ProfilingCategoryPair aCategoryPair);
+
+// `PayloadType` is a sub-class of MarkerPayload, `parenthesizedPayloadArgs` is
+// the argument list used to construct that `PayloadType`. E.g.:
+// `PROFILER_ADD_MARKER_WITH_PAYLOAD("Load", DOM, TextMarkerPayload,
+//                                   ("text", start, end, ds, dsh))`
+#  define PROFILER_ADD_MARKER_WITH_PAYLOAD(                            \
+      markerName, categoryPair, PayloadType, parenthesizedPayloadArgs) \
+    do {                                                               \
+      AUTO_PROFILER_STATS(add_marker_with_##PayloadType);              \
+      ::profiler_add_marker(markerName,                                \
+                            ::JS::ProfilingCategoryPair::categoryPair, \
+                            PayloadType parenthesizedPayloadArgs);     \
+    } while (false)
+
 void profiler_add_marker(const char* aMarkerName,
                          JS::ProfilingCategoryPair aCategoryPair,
-                         mozilla::UniquePtr<ProfilerMarkerPayload> aPayload);
+                         const ProfilerMarkerPayload& aPayload);
+
 void profiler_add_js_marker(const char* aMarkerName);
 void profiler_add_js_allocation_marker(JS::RecordAllocationInfo&& info);
+void profiler_add_native_allocation_marker(int64_t aSize);
+bool profiler_could_be_locked_on_current_thread();
 
 // Insert a marker in the profile timeline for a specified thread.
 void profiler_add_marker_for_thread(
@@ -754,7 +841,7 @@ class MOZ_RAII AutoProfilerTextMarker {
       : mMarkerName(aMarkerName),
         mText(aText),
         mCategoryPair(aCategoryPair),
-        mStartTime(mozilla::TimeStamp::Now()),
+        mStartTime(mozilla::TimeStamp::NowUnfuzzed()),
         mCause(std::move(aCause)),
         mDocShellId(aDocShellId),
         mDocShellHistoryId(aDocShellHistoryId) {
@@ -763,7 +850,7 @@ class MOZ_RAII AutoProfilerTextMarker {
 
   ~AutoProfilerTextMarker() {
     profiler_add_text_marker(mMarkerName, mText, mCategoryPair, mStartTime,
-                             mozilla::TimeStamp::Now(), mDocShellId,
+                             mozilla::TimeStamp::NowUnfuzzed(), mDocShellId,
                              mDocShellHistoryId, std::move(mCause));
   }
 
@@ -814,9 +901,10 @@ mozilla::UniquePtr<char[]> profiler_get_profile(double aSinceTime = 0,
 
 // Write the profile for this process (excluding subprocesses) into aWriter.
 // Returns false if the profiler is inactive.
-bool profiler_stream_json_for_this_process(SpliceableJSONWriter& aWriter,
-                                           double aSinceTime = 0,
-                                           bool aIsShuttingDown = false);
+bool profiler_stream_json_for_this_process(
+    SpliceableJSONWriter& aWriter, double aSinceTime = 0,
+    bool aIsShuttingDown = false,
+    ProfilerCodeAddressService* aService = nullptr);
 
 // Get the profile and write it into a file. A no-op if the profile is
 // inactive.
@@ -847,6 +935,17 @@ class MOZ_RAII AutoProfilerInit {
   MOZ_DECL_USE_GUARD_OBJECT_NOTIFIER
 };
 
+class MOZ_RAII AutoProfilerInit2 {
+ public:
+  explicit AutoProfilerInit2(MOZ_GUARD_OBJECT_NOTIFIER_ONLY_PARAM) {
+    MOZ_GUARD_OBJECT_NOTIFIER_INIT;
+    profiler_init_threadmanager();
+  }
+
+ private:
+  MOZ_DECL_USE_GUARD_OBJECT_NOTIFIER
+};
+
 // Convenience class to register and unregister a thread with the profiler.
 // Needs to be the first object on the stack of the thread.
 class MOZ_RAII AutoProfilerRegisterThread final {
diff --git a/tools/profiler/public/ProfilerCodeAddressService.h b/tools/profiler/public/ProfilerCodeAddressService.h
new file mode 100644
index 0000000000..c21fc1ee08
--- /dev/null
+++ b/tools/profiler/public/ProfilerCodeAddressService.h
@@ -0,0 +1,49 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef ProfilerCodeAddressService_h
+#define ProfilerCodeAddressService_h
+
+#include "CodeAddressService.h"
+
+namespace mozilla {
+
+// This SymbolTable struct, and the CompactSymbolTable struct in the
+// profiler rust module, have the exact same memory layout.
+// nsTArray and ThinVec are FFI-compatible, because the thin-vec crate is
+// being compiled with the "gecko-ffi" feature enabled.
+struct SymbolTable {
+  SymbolTable() = default;
+  SymbolTable(SymbolTable&& aOther) = default;
+
+  nsTArray<uint32_t> mAddrs;
+  nsTArray<uint32_t> mIndex;
+  nsTArray<uint8_t> mBuffer;
+};
+
+}  // namespace mozilla
+
+/**
+ * Cache and look up function symbol names.
+ *
+ * We don't template this on AllocPolicy since we need to use nsTArray in
+ * SymbolTable above, which doesn't work with AllocPolicy.  (We can't switch
+ * to Vector, as we would lose FFI compatibility with ThinVec.)
+ */
+class ProfilerCodeAddressService : public mozilla::CodeAddressService<> {
+ public:
+  // Like GetLocation, but only returns the symbol name.
+  bool GetFunction(const void* aPc, nsACString& aResult);
+
+ private:
+#ifdef XP_LINUX
+  // Map of library names (owned by mLibraryStrings) to SymbolTables filled
+  // in by profiler_get_symbol_table.
+  mozilla::HashMap<const char*, mozilla::SymbolTable,
+                   mozilla::DefaultHasher<const char*>, AllocPolicy>
+      mSymbolTables;
+#endif
+};
+
+#endif  // ProfilerCodeAddressService_h
diff --git a/tools/profiler/public/ProfilerCounts.h b/tools/profiler/public/ProfilerCounts.h
index e433f88b6b..0ea64c01bf 100644
--- a/tools/profiler/public/ProfilerCounts.h
+++ b/tools/profiler/public/ProfilerCounts.h
@@ -90,11 +90,14 @@ class BaseProfilerCount {
 #  endif
     // Can't call profiler_* here since this may be non-xul-library
   }
-#  ifdef DEBUG
-  ~BaseProfilerCount() { mCanary = 0; }
-#  endif
 
-  void Sample(int64_t& aCounter, uint64_t& aNumber) {
+  virtual ~BaseProfilerCount() {
+#  ifdef DEBUG
+    mCanary = 0;
+#  endif
+  }
+
+  virtual void Sample(int64_t& aCounter, uint64_t& aNumber) {
     MOZ_ASSERT(mCanary == COUNTER_CANARY);
 
     aCounter = *mCounter;
diff --git a/tools/profiler/public/ProfilerMarkerPayload.h b/tools/profiler/public/ProfilerMarkerPayload.h
index 8b2b441561..341cd9f83c 100644
--- a/tools/profiler/public/ProfilerMarkerPayload.h
+++ b/tools/profiler/public/ProfilerMarkerPayload.h
@@ -5,7 +5,9 @@
 #ifndef ProfilerMarkerPayload_h
 #define ProfilerMarkerPayload_h
 
+#include "mozilla/Atomics.h"
 #include "mozilla/Attributes.h"
+#include "mozilla/BlocksRingBuffer.h"
 #include "mozilla/Maybe.h"
 #include "mozilla/RefPtr.h"
 #include "mozilla/TimeStamp.h"
@@ -43,58 +45,143 @@ class ProfilerMarkerPayload {
       const mozilla::Maybe<nsID>& aDocShellId = mozilla::Nothing(),
       const mozilla::Maybe<uint32_t>& aDocShellHistoryId = mozilla::Nothing(),
       UniqueProfilerBacktrace aStack = nullptr)
-      : mStack(std::move(aStack)),
-        mDocShellId(aDocShellId),
-        mDocShellHistoryId(aDocShellHistoryId) {}
+      : mCommonProps{mozilla::TimeStamp{}, mozilla::TimeStamp{},
+                     std::move(aStack), std::move(aDocShellId),
+                     std::move(aDocShellHistoryId)} {}
 
   ProfilerMarkerPayload(
       const mozilla::TimeStamp& aStartTime, const mozilla::TimeStamp& aEndTime,
       const mozilla::Maybe<nsID>& aDocShellId = mozilla::Nothing(),
       const mozilla::Maybe<uint32_t>& aDocShellHistoryId = mozilla::Nothing(),
       UniqueProfilerBacktrace aStack = nullptr)
-      : mStartTime(aStartTime),
-        mEndTime(aEndTime),
-        mStack(std::move(aStack)),
-        mDocShellId(aDocShellId),
-        mDocShellHistoryId(aDocShellHistoryId) {}
+      : mCommonProps{aStartTime, aEndTime, std::move(aStack),
+                     std::move(aDocShellId), std::move(aDocShellHistoryId)} {}
 
   virtual ~ProfilerMarkerPayload() {}
 
+  // Compute the number of bytes needed to serialize the `DeserializerTag` and
+  // payload, including in the no-payload (nullptr) case.
+  static mozilla::BlocksRingBuffer::Length TagAndSerializationBytes(
+      const ProfilerMarkerPayload* aPayload) {
+    if (!aPayload) {
+      return sizeof(DeserializerTag);
+    }
+    return aPayload->TagAndSerializationBytes();
+  }
+
+  // Serialize the payload into an EntryWriter, including in the no-payload
+  // (nullptr) case. Must be of the exact size given by
+  // `TagAndSerializationBytes(aPayload)`.
+  static void TagAndSerialize(
+      const ProfilerMarkerPayload* aPayload,
+      mozilla::BlocksRingBuffer::EntryWriter& aEntryWriter) {
+    if (!aPayload) {
+      aEntryWriter.WriteObject(DeserializerTag(0));
+      return;
+    }
+    aPayload->SerializeTagAndPayload(aEntryWriter);
+  }
+
+  // Deserialize a payload from an EntryReader, including in the no-payload
+  // (nullptr) case.
+  static mozilla::UniquePtr<ProfilerMarkerPayload> DeserializeTagAndPayload(
+      mozilla::BlocksRingBuffer::EntryReader& aER) {
+    const auto tag = aER.ReadObject<DeserializerTag>();
+    Deserializer deserializer = DeserializerForTag(tag);
+    return deserializer(aER);
+  }
+
   virtual void StreamPayload(SpliceableJSONWriter& aWriter,
                              const mozilla::TimeStamp& aProcessStartTime,
-                             UniqueStacks& aUniqueStacks) = 0;
+                             UniqueStacks& aUniqueStacks) const = 0;
 
-  mozilla::TimeStamp GetStartTime() const { return mStartTime; }
+  mozilla::TimeStamp GetStartTime() const { return mCommonProps.mStartTime; }
 
  protected:
-  void StreamType(const char* aMarkerType, SpliceableJSONWriter& aWriter);
+  // A `Deserializer` is a free function that can read a serialized payload from
+  // an `EntryReader` and return a reconstructed `ProfilerMarkerPayload`
+  // sub-object (may be null if there was no payload).
+  typedef mozilla::UniquePtr<ProfilerMarkerPayload> (*Deserializer)(
+      mozilla::BlocksRingBuffer::EntryReader&);
+
+  // A `DeserializerTag` will be added before the payload, to help select the
+  // correct deserializer when reading back the payload.
+  using DeserializerTag = unsigned char;
+
+  // This needs to be big enough to handle all possible sub-types of
+  // ProfilerMarkerPayload.
+  static constexpr DeserializerTag DeserializerMax = 32;
+
+  // We need an atomic type that can hold a `DeserializerTag`. (Atomic doesn't
+  // work with too-small types.)
+  using DeserializerTagAtomic = int;
+
+  // Number of currently-registered deserializers.
+  static mozilla::Atomic<DeserializerTagAtomic, mozilla::ReleaseAcquire>
+      sDeserializerCount;
+
+  // List of currently-registered deserializers.
+  // sDeserializers[0] is a no-payload deserializer.
+  static Deserializer sDeserializers[DeserializerMax];
+
+  // Get the `DeserializerTag` for a `Deserializer` (which gets registered on
+  // the first call.) Tag 0 means no payload; a null `aDeserializer` gives that
+  // 0 tag.
+  static DeserializerTag TagForDeserializer(Deserializer aDeserializer);
+
+  // Get the `Deserializer` for a given `DeserializerTag`.
+  // Tag 0 is reserved as no-payload deserializer (which returns nullptr).
+  static Deserializer DeserializerForTag(DeserializerTag aTag);
+
+  struct CommonProps {
+    mozilla::TimeStamp mStartTime;
+    mozilla::TimeStamp mEndTime;
+    UniqueProfilerBacktrace mStack;
+    mozilla::Maybe<nsID> mDocShellId;
+    mozilla::Maybe<uint32_t> mDocShellHistoryId;
+  };
+
+  // Deserializers can use this base constructor.
+  explicit ProfilerMarkerPayload(CommonProps&& aCommonProps)
+      : mCommonProps(std::move(aCommonProps)) {}
+
+  // Serialization/deserialization of common props in ProfilerMarkerPayload.
+  mozilla::BlocksRingBuffer::Length CommonPropsTagAndSerializationBytes() const;
+  void SerializeTagAndCommonProps(
+      DeserializerTag aDeserializerTag,
+      mozilla::BlocksRingBuffer::EntryWriter& aEntryWriter) const;
+  static CommonProps DeserializeCommonProps(
+      mozilla::BlocksRingBuffer::EntryReader& aEntryReader);
+
+  void StreamType(const char* aMarkerType, SpliceableJSONWriter& aWriter) const;
+
   void StreamCommonProps(const char* aMarkerType, SpliceableJSONWriter& aWriter,
                          const mozilla::TimeStamp& aProcessStartTime,
-                         UniqueStacks& aUniqueStacks);
-
-  void SetStack(UniqueProfilerBacktrace aStack) { mStack = std::move(aStack); }
-
-  void SetDocShellHistoryId(
-      const mozilla::Maybe<uint32_t>& aDocShellHistoryId) {
-    mDocShellHistoryId = aDocShellHistoryId;
-  }
-
-  void SetDocShellId(const mozilla::Maybe<nsID>& aDocShellId) {
-    mDocShellId = aDocShellId;
-  }
+                         UniqueStacks& aUniqueStacks) const;
 
  private:
-  mozilla::TimeStamp mStartTime;
-  mozilla::TimeStamp mEndTime;
-  UniqueProfilerBacktrace mStack;
-  mozilla::Maybe<nsID> mDocShellId;
-  mozilla::Maybe<uint32_t> mDocShellHistoryId;
+  // Compute the number of bytes needed to serialize payload in
+  // `SerializeTagAndPayload` below.
+  virtual mozilla::BlocksRingBuffer::Length TagAndSerializationBytes()
+      const = 0;
+
+  // Serialize the payload into an EntryWriter.
+  // Must be of the exact size given by `TagAndSerializationBytes()`.
+  virtual void SerializeTagAndPayload(
+      mozilla::BlocksRingBuffer::EntryWriter& aEntryWriter) const = 0;
+
+  CommonProps mCommonProps;
 };
 
-#define DECL_STREAM_PAYLOAD                                               \
-  virtual void StreamPayload(SpliceableJSONWriter& aWriter,               \
-                             const mozilla::TimeStamp& aProcessStartTime, \
-                             UniqueStacks& aUniqueStacks) override;
+#define DECL_STREAM_PAYLOAD                                                    \
+  void StreamPayload(SpliceableJSONWriter& aWriter,                            \
+                     const mozilla::TimeStamp& aProcessStartTime,              \
+                     UniqueStacks& aUniqueStacks) const override;              \
+  static mozilla::UniquePtr<ProfilerMarkerPayload> Deserialize(                \
+      mozilla::BlocksRingBuffer::EntryReader& aEntryReader);                   \
+  mozilla::BlocksRingBuffer::Length TagAndSerializationBytes() const override; \
+  void SerializeTagAndPayload(                                                 \
+      mozilla::BlocksRingBuffer::EntryWriter& aEntryWriter) const override;
 
 // TODO: Increase the coverage of tracing markers that include DocShell
 // information
@@ -105,16 +192,25 @@ class TracingMarkerPayload : public ProfilerMarkerPayload {
       const mozilla::Maybe<nsID>& aDocShellId = mozilla::Nothing(),
       const mozilla::Maybe<uint32_t>& aDocShellHistoryId = mozilla::Nothing(),
       UniqueProfilerBacktrace aCause = nullptr)
-      : mCategory(aCategory), mKind(aKind) {
-    if (aCause) {
-      SetStack(std::move(aCause));
-    }
-    SetDocShellId(aDocShellId);
-    SetDocShellHistoryId(aDocShellHistoryId);
-  }
+      : ProfilerMarkerPayload(aDocShellId, aDocShellHistoryId,
+                              std::move(aCause)),
+        mCategory(aCategory),
+        mKind(aKind) {}
 
   DECL_STREAM_PAYLOAD
 
+ protected:
+  TracingMarkerPayload(CommonProps&& aCommonProps, const char* aCategory,
+                       TracingKind aKind)
+      : ProfilerMarkerPayload(std::move(aCommonProps)),
+        mCategory(aCategory),
+        mKind(aKind) {}
+
+  // May be used by derived classes.
+  void SerializeTagAndPayload(
+      DeserializerTag aDeserializerTag,
+      mozilla::BlocksRingBuffer::EntryWriter& aEntryWriter) const;
+
  private:
   const char* mCategory;
   TracingKind mKind;
@@ -138,6 +234,14 @@ class FileIOMarkerPayload : public ProfilerMarkerPayload {
   DECL_STREAM_PAYLOAD
 
  private:
+  FileIOMarkerPayload(CommonProps&& aCommonProps, const char* aSource,
+                      mozilla::UniqueFreePtr<char>&& aOperation,
+                      mozilla::UniqueFreePtr<char>&& aFilename)
+      : ProfilerMarkerPayload(std::move(aCommonProps)),
+        mSource(aSource),
+        mOperation(std::move(aOperation)),
+        mFilename(std::move(aFilename)) {}
+
   const char* mSource;
   mozilla::UniqueFreePtr<char> mOperation;
   mozilla::UniqueFreePtr<char> mFilename;
@@ -157,6 +261,13 @@ class DOMEventMarkerPayload : public TracingMarkerPayload {
   DECL_STREAM_PAYLOAD
 
  private:
+  DOMEventMarkerPayload(CommonProps&& aCommonProps, const char* aCategory,
+                        TracingKind aKind, mozilla::TimeStamp aTimeStamp,
+                        nsString aEventType)
+      : TracingMarkerPayload(std::move(aCommonProps), aCategory, aKind),
+        mTimeStamp(aTimeStamp),
+        mEventType(aEventType) {}
+
   mozilla::TimeStamp mTimeStamp;
   nsString mEventType;
 };
@@ -189,6 +300,16 @@ class UserTimingMarkerPayload : public ProfilerMarkerPayload {
   DECL_STREAM_PAYLOAD
 
  private:
+  UserTimingMarkerPayload(CommonProps&& aCommonProps, const char* aEntryType,
+                          nsString&& aName,
+                          mozilla::Maybe<nsString>&& aStartMark,
+                          mozilla::Maybe<nsString>&& aEndMark)
+      : ProfilerMarkerPayload(std::move(aCommonProps)),
+        mEntryType(aEntryType),
+        mName(std::move(aName)),
+        mStartMark(std::move(aStartMark)),
+        mEndMark(std::move(aEndMark)) {}
+
   // Either "mark" or "measure".
   const char* mEntryType;
   nsString mName;
@@ -210,6 +331,13 @@ class LayerTranslationMarkerPayload : public ProfilerMarkerPayload {
   DECL_STREAM_PAYLOAD
 
  private:
+  LayerTranslationMarkerPayload(CommonProps&& aCommonProps,
+                                mozilla::layers::Layer* aLayer,
+                                mozilla::gfx::Point aPoint)
+      : ProfilerMarkerPayload(std::move(aCommonProps)),
+        mLayer(aLayer),
+        mPoint(aPoint) {}
+
   mozilla::layers::Layer* mLayer;
   mozilla::gfx::Point mPoint;
 };
@@ -223,6 +351,10 @@ class VsyncMarkerPayload : public ProfilerMarkerPayload {
       : ProfilerMarkerPayload(aVsyncTimestamp, aVsyncTimestamp) {}
 
   DECL_STREAM_PAYLOAD
+
+ private:
+  explicit VsyncMarkerPayload(CommonProps&& aCommonProps)
+      : ProfilerMarkerPayload(std::move(aCommonProps)) {}
 };
 
 class NetworkMarkerPayload : public ProfilerMarkerPayload {
@@ -252,6 +384,22 @@ class NetworkMarkerPayload : public ProfilerMarkerPayload {
   DECL_STREAM_PAYLOAD
 
  private:
+  NetworkMarkerPayload(CommonProps&& aCommonProps, int64_t aID,
+                       mozilla::UniqueFreePtr<char>&& aURI,
+                       mozilla::UniqueFreePtr<char>&& aRedirectURI,
+                       NetworkLoadType aType, int32_t aPri, int64_t aCount,
+                       mozilla::net::TimingStruct aTimings,
+                       mozilla::net::CacheDisposition aCacheDisposition)
+      : ProfilerMarkerPayload(std::move(aCommonProps)),
+        mID(aID),
+        mURI(std::move(aURI)),
+        mRedirectURI(std::move(aRedirectURI)),
+        mType(aType),
+        mPri(aPri),
+        mCount(aCount),
+        mTimings(aTimings),
+        mCacheDisposition(aCacheDisposition) {}
+
   int64_t mID;
   mozilla::UniqueFreePtr<char> mURI;
   mozilla::UniqueFreePtr<char> mRedirectURI;
@@ -276,6 +424,14 @@ class ScreenshotPayload : public ProfilerMarkerPayload {
   DECL_STREAM_PAYLOAD
 
  private:
+  ScreenshotPayload(CommonProps&& aCommonProps, nsCString&& aScreenshotDataURL,
+                    mozilla::gfx::IntSize aWindowSize,
+                    uintptr_t aWindowIdentifier)
+      : ProfilerMarkerPayload(std::move(aCommonProps)),
+        mScreenshotDataURL(std::move(aScreenshotDataURL)),
+        mWindowSize(aWindowSize),
+        mWindowIdentifier(aWindowIdentifier) {}
+
   nsCString mScreenshotDataURL;
   mozilla::gfx::IntSize mWindowSize;
   uintptr_t mWindowIdentifier;
@@ -292,6 +448,11 @@ class GCSliceMarkerPayload : public ProfilerMarkerPayload {
   DECL_STREAM_PAYLOAD
 
  private:
+  GCSliceMarkerPayload(CommonProps&& aCommonProps,
+                       JS::UniqueChars&& aTimingJSON)
+      : ProfilerMarkerPayload(std::move(aCommonProps)),
+        mTimingJSON(std::move(aTimingJSON)) {}
+
   JS::UniqueChars mTimingJSON;
 };
 
@@ -306,6 +467,11 @@ class GCMajorMarkerPayload : public ProfilerMarkerPayload {
   DECL_STREAM_PAYLOAD
 
  private:
+  GCMajorMarkerPayload(CommonProps&& aCommonProps,
+                       JS::UniqueChars&& aTimingJSON)
+      : ProfilerMarkerPayload(std::move(aCommonProps)),
+        mTimingJSON(std::move(aTimingJSON)) {}
+
   JS::UniqueChars mTimingJSON;
 };
 
@@ -320,6 +486,11 @@ class GCMinorMarkerPayload : public ProfilerMarkerPayload {
   DECL_STREAM_PAYLOAD
 
  private:
+  GCMinorMarkerPayload(CommonProps&& aCommonProps,
+                       JS::UniqueChars&& aTimingData)
+      : ProfilerMarkerPayload(std::move(aCommonProps)),
+        mTimingData(std::move(aTimingData)) {}
+
   JS::UniqueChars mTimingData;
 };
 
@@ -331,6 +502,8 @@ class HangMarkerPayload : public ProfilerMarkerPayload {
 
   DECL_STREAM_PAYLOAD
  private:
+  explicit HangMarkerPayload(CommonProps&& aCommonProps)
+      : ProfilerMarkerPayload(std::move(aCommonProps)) {}
 };
 
 class StyleMarkerPayload : public ProfilerMarkerPayload {
@@ -342,16 +515,16 @@ class StyleMarkerPayload : public ProfilerMarkerPayload {
                      const mozilla::Maybe<nsID>& aDocShellId,
                      const mozilla::Maybe<uint32_t>& aDocShellHistoryId)
       : ProfilerMarkerPayload(aStartTime, aEndTime, aDocShellId,
-                              aDocShellHistoryId),
-        mStats(aStats) {
-    if (aCause) {
-      SetStack(std::move(aCause));
-    }
-  }
+                              aDocShellHistoryId, std::move(aCause)),
+        mStats(aStats) {}
 
   DECL_STREAM_PAYLOAD
 
  private:
+  StyleMarkerPayload(CommonProps&& aCommonProps,
+                     mozilla::ServoTraversalStatistics aStats)
+      : ProfilerMarkerPayload(std::move(aCommonProps)), mStats(aStats) {}
+
   mozilla::ServoTraversalStatistics mStats;
 };
 
@@ -362,6 +535,10 @@ class LongTaskMarkerPayload : public ProfilerMarkerPayload {
       : ProfilerMarkerPayload(aStartTime, aEndTime) {}
 
   DECL_STREAM_PAYLOAD
+
+ private:
+  explicit LongTaskMarkerPayload(CommonProps&& aCommonProps)
+      : ProfilerMarkerPayload(std::move(aCommonProps)) {}
 };
 
 class TextMarkerPayload : public ProfilerMarkerPayload {
@@ -396,6 +573,10 @@ class TextMarkerPayload : public ProfilerMarkerPayload {
   DECL_STREAM_PAYLOAD
 
  private:
+  TextMarkerPayload(CommonProps&& aCommonProps, nsCString&& aText)
+      : ProfilerMarkerPayload(std::move(aCommonProps)),
+        mText(std::move(aText)) {}
+
   nsCString mText;
 };
 
@@ -410,6 +591,12 @@ class LogMarkerPayload : public ProfilerMarkerPayload {
   DECL_STREAM_PAYLOAD
 
  private:
+  LogMarkerPayload(CommonProps&& aCommonProps, nsAutoCStringN<32>&& aModule,
+                   nsCString&& aText)
+      : ProfilerMarkerPayload(std::move(aCommonProps)),
+        mModule(std::move(aModule)),
+        mText(std::move(aText)) {}
+
   nsAutoCStringN<32> mModule;  // longest known LazyLogModule name is ~24
   nsCString mText;
 };
@@ -417,7 +604,7 @@ class LogMarkerPayload : public ProfilerMarkerPayload {
 class JsAllocationMarkerPayload : public ProfilerMarkerPayload {
  public:
   JsAllocationMarkerPayload(const mozilla::TimeStamp& aStartTime,
-                            const JS::RecordAllocationInfo& aInfo,
+                            JS::RecordAllocationInfo&& aInfo,
                             UniqueProfilerBacktrace aStack)
       : ProfilerMarkerPayload(aStartTime, aStartTime, mozilla::Nothing(),
                               mozilla::Nothing(), std::move(aStack)),
@@ -427,8 +614,6 @@ class JsAllocationMarkerPayload : public ProfilerMarkerPayload {
         mDescriptiveTypeName(aInfo.descriptiveTypeName
                                  ? NS_xstrdup(aInfo.descriptiveTypeName)
                                  : nullptr),
-        mScriptFilename(aInfo.scriptFilename ? strdup(aInfo.scriptFilename)
-                                             : nullptr),
         // The coarseType points to a string literal, so does not need to be
         // duplicated.
         mCoarseType(aInfo.coarseType),
@@ -438,10 +623,23 @@ class JsAllocationMarkerPayload : public ProfilerMarkerPayload {
   DECL_STREAM_PAYLOAD
 
  private:
+  JsAllocationMarkerPayload(
+      CommonProps&& aCommonProps,
+      mozilla::UniqueFreePtr<const char16_t>&& aTypeName,
+      mozilla::UniqueFreePtr<const char>&& aClassName,
+      mozilla::UniqueFreePtr<const char16_t>&& aDescriptiveTypeName,
+      const char* aCoarseType, uint64_t aSize, bool aInNursery)
+      : ProfilerMarkerPayload(std::move(aCommonProps)),
+        mTypeName(std::move(aTypeName)),
+        mClassName(std::move(aClassName)),
+        mDescriptiveTypeName(std::move(aDescriptiveTypeName)),
+        mCoarseType(aCoarseType),
+        mSize(aSize),
+        mInNursery(aInNursery) {}
+
   mozilla::UniqueFreePtr<const char16_t> mTypeName;
   mozilla::UniqueFreePtr<const char> mClassName;
   mozilla::UniqueFreePtr<const char16_t> mDescriptiveTypeName;
-  mozilla::UniqueFreePtr<const char> mScriptFilename;
   // Points to a string literal, so does not need to be freed.
   const char* mCoarseType;
 
@@ -452,4 +650,71 @@ class JsAllocationMarkerPayload : public ProfilerMarkerPayload {
   bool mInNursery;
 };
 
+// This payload is for collecting information about native allocations. There is
+// a memory hook into malloc and other memory functions that can sample a subset
+// of the allocations. This information is then stored in this payload.
+class NativeAllocationMarkerPayload : public ProfilerMarkerPayload {
+ public:
+  NativeAllocationMarkerPayload(const mozilla::TimeStamp& aStartTime,
+                                const int64_t aSize,
+                                UniqueProfilerBacktrace aStack)
+      : ProfilerMarkerPayload(aStartTime, aStartTime, mozilla::Nothing(),
+                              mozilla::Nothing(), std::move(aStack)),
+        mSize(aSize) {}
+
+  DECL_STREAM_PAYLOAD
+
+ private:
+  NativeAllocationMarkerPayload(CommonProps&& aCommonProps, int64_t aSize)
+      : ProfilerMarkerPayload(std::move(aCommonProps)), mSize(aSize) {}
+
+  // The size in bytes of the allocation or de-allocation.
+  int64_t mSize;
+};
+
+namespace mozilla {
+
+// Serialize a pointed-at ProfilerMarkerPayload, may be null when there are no
+// payloads.
+template <>
+struct BlocksRingBuffer::Serializer<const ProfilerMarkerPayload*> {
+  static Length Bytes(const ProfilerMarkerPayload* aPayload) {
+    return ProfilerMarkerPayload::TagAndSerializationBytes(aPayload);
+  }
+
+  static void Write(EntryWriter& aEW, const ProfilerMarkerPayload* aPayload) {
+    ProfilerMarkerPayload::TagAndSerialize(aPayload, aEW);
+  }
+};
+
+// Serialize a pointed-at ProfilerMarkerPayload, may be null when there are no
+// payloads.
+template <>
+struct BlocksRingBuffer::Serializer<UniquePtr<ProfilerMarkerPayload>> {
+  static Length Bytes(const UniquePtr<ProfilerMarkerPayload>& aPayload) {
+    return ProfilerMarkerPayload::TagAndSerializationBytes(aPayload.get());
+  }
+
+  static void Write(EntryWriter& aEW,
+                    const UniquePtr<ProfilerMarkerPayload>& aPayload) {
+    ProfilerMarkerPayload::TagAndSerialize(aPayload.get(), aEW);
+  }
+};
+
+// Deserialize a ProfilerMarkerPayload into a UniquePtr, may be null if there
+// are no payloads.
+template <>
+struct BlocksRingBuffer::Deserializer<UniquePtr<ProfilerMarkerPayload>> {
+  static void ReadInto(EntryReader& aER,
+                       UniquePtr<ProfilerMarkerPayload>& aPayload) {
+    aPayload = Read(aER);
+  }
+
+  static UniquePtr<ProfilerMarkerPayload> Read(EntryReader& aER) {
+    return ProfilerMarkerPayload::DeserializeTagAndPayload(aER);
+  }
+};
+
+}  // namespace mozilla
+
 #endif  // ProfilerMarkerPayload_h
diff --git a/tools/profiler/rust-helper/Cargo.toml b/tools/profiler/rust-helper/Cargo.toml
index 1c82f4b3b7..54e2ce442a 100644
--- a/tools/profiler/rust-helper/Cargo.toml
+++ b/tools/profiler/rust-helper/Cargo.toml
@@ -5,6 +5,7 @@ authors = ["Markus Stange <mstange@themasta.com>"]
 
 [dependencies]
 memmap = "0.7"
+rustc-demangle = "0.1"
 uuid = "0.8"
 
 [dependencies.object]
diff --git a/tools/profiler/rust-helper/src/elf.rs b/tools/profiler/rust-helper/src/elf.rs
index a4fbcc5629..e2d74e9365 100644
--- a/tools/profiler/rust-helper/src/elf.rs
+++ b/tools/profiler/rust-helper/src/elf.rs
@@ -1,9 +1,13 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
 use compact_symbol_table::CompactSymbolTable;
+use goblin::elf;
 use object::SymbolKind;
 use object::read::{ElfFile, Object};
-use std::collections::HashMap;
 use std::cmp;
-use goblin::elf;
+use std::collections::HashMap;
 use uuid::Uuid;
 
 const UUID_SIZE: usize = 16;
@@ -11,41 +15,44 @@ const PAGE_SIZE: usize = 4096;
 
 fn get_symbol_map<'a, 'b, T>(object_file: &'b T) -> HashMap<u32, &'a str>
 where
-  T: Object<'a, 'b>,
+    T: Object<'a, 'b>,
 {
-  object_file
-    .dynamic_symbols()
-    .chain(object_file.symbols())
-    .filter(|(_, symbol)| symbol.kind() == SymbolKind::Text)
-    .filter_map(|(_, symbol)| symbol.name().map(|name| (symbol.address() as u32, name)))
-    .collect()
+    object_file
+        .dynamic_symbols()
+        .chain(object_file.symbols())
+        .filter(|(_, symbol)| symbol.kind() == SymbolKind::Text)
+        .filter_map(|(_, symbol)| symbol.name().map(|name| (symbol.address() as u32, name)))
+        .collect()
 }
 
-pub fn get_compact_symbol_table(buffer: &[u8], breakpad_id: &str) -> Option<CompactSymbolTable> {
-  let elf_file = ElfFile::parse(buffer).ok()?;
-  let elf_id = get_elf_id(&elf_file, buffer)?;
-  if format!("{:X}0", elf_id.simple()) != breakpad_id {
-    return None;
-  }
-  return Some(CompactSymbolTable::from_map(get_symbol_map(&elf_file)));
+pub fn get_compact_symbol_table(
+    buffer: &[u8],
+    breakpad_id: Option<&str>,
+) -> Option<CompactSymbolTable> {
+    let elf_file = ElfFile::parse(buffer).ok()?;
+    let elf_id = get_elf_id(&elf_file, buffer)?;
+    if !breakpad_id.map_or(true, |id| id == format!("{:X}0", elf_id.to_simple_ref())) {
+        return None;
+    }
+    return Some(CompactSymbolTable::from_map(get_symbol_map(&elf_file)));
 }
 
 fn create_elf_id(identifier: &[u8], little_endian: bool) -> Uuid {
-  // Make sure that we have exactly UUID_SIZE bytes available
-  let mut data = [0 as u8; UUID_SIZE];
-  let len = cmp::min(identifier.len(), UUID_SIZE);
-  data[0..len].copy_from_slice(&identifier[0..len]);
+    // Make sure that we have exactly UUID_SIZE bytes available
+    let mut data = [0 as u8; UUID_SIZE];
+    let len = cmp::min(identifier.len(), UUID_SIZE);
+    data[0..len].copy_from_slice(&identifier[0..len]);
 
-  if little_endian {
-    // The file ELF file targets a little endian architecture. Convert to
-    // network byte order (big endian) to match the Breakpad processor's
-    // expectations. For big endian object files, this is not needed.
-    data[0..4].reverse(); // uuid field 1
-    data[4..6].reverse(); // uuid field 2
-    data[6..8].reverse(); // uuid field 3
-  }
+    if little_endian {
+        // The file ELF file targets a little endian architecture. Convert to
+        // network byte order (big endian) to match the Breakpad processor's
+        // expectations. For big endian object files, this is not needed.
+        data[0..4].reverse(); // uuid field 1
+        data[4..6].reverse(); // uuid field 2
+        data[6..8].reverse(); // uuid field 3
+    }
 
-  Uuid::from_bytes(data)
+    Uuid::from_bytes(data)
 }
 
 /// Tries to obtain the object identifier of an ELF object.
@@ -61,35 +68,33 @@ fn create_elf_id(identifier: &[u8], little_endian: bool) -> Uuid {
 ///
 /// If all of the above fails, this function will return `None`.
 pub fn get_elf_id(elf_file: &ElfFile, data: &[u8]) -> Option<Uuid> {
-  if let Some(identifier) = elf_file.build_id() {
-    return Some(create_elf_id(identifier, elf_file.elf().little_endian));
-  }
-
-  // We were not able to locate the build ID, so fall back to hashing the
-  // first page of the ".text" (program code) section. This algorithm XORs
-  // 16-byte chunks directly into a UUID buffer.
-  if let Some(section_data) = find_text_section(elf_file.elf(), data) {
-    let mut hash = [0; UUID_SIZE];
-    for i in 0..cmp::min(section_data.len(), PAGE_SIZE) {
-      hash[i % UUID_SIZE] ^= section_data[i];
+    if let Some(identifier) = elf_file.build_id() {
+        return Some(create_elf_id(identifier, elf_file.elf().little_endian));
     }
 
-    return Some(create_elf_id(&hash, elf_file.elf().little_endian));
-  }
+    // We were not able to locate the build ID, so fall back to hashing the
+    // first page of the ".text" (program code) section. This algorithm XORs
+    // 16-byte chunks directly into a UUID buffer.
+    if let Some(section_data) = find_text_section(elf_file.elf(), data) {
+        let mut hash = [0; UUID_SIZE];
+        for i in 0..cmp::min(section_data.len(), PAGE_SIZE) {
+            hash[i % UUID_SIZE] ^= section_data[i];
+        }
 
-  None
+        return Some(create_elf_id(&hash, elf_file.elf().little_endian));
+    }
+
+    None
 }
 
 /// Returns a reference to the data of the the .text section in an ELF binary.
-fn find_text_section<'elf, 'data>(
-  elf: &'elf elf::Elf,
-  data: &'data [u8],
-) -> Option<&'data[u8]> {
-  elf.section_headers.iter().find_map(|header| {
-    match (header.sh_type, elf.shdr_strtab.get(header.sh_name)) {
-      (elf::section_header::SHT_PROGBITS, Some(Ok(".text"))) =>
-        Some(&data[header.sh_offset as usize..][..header.sh_size as usize]),
-      _ => None
-    }
-  })
+fn find_text_section<'elf, 'data>(elf: &'elf elf::Elf, data: &'data [u8]) -> Option<&'data [u8]> {
+    elf.section_headers.iter().find_map(|header| {
+        match (header.sh_type, elf.shdr_strtab.get(header.sh_name)) {
+            (elf::section_header::SHT_PROGBITS, Some(Ok(".text"))) => {
+                Some(&data[header.sh_offset as usize..][..header.sh_size as usize])
+            }
+            _ => None,
+        }
+    })
 }
diff --git a/tools/profiler/rust-helper/src/lib.rs b/tools/profiler/rust-helper/src/lib.rs
index 3c4a0cfece..a22e631852 100644
--- a/tools/profiler/rust-helper/src/lib.rs
+++ b/tools/profiler/rust-helper/src/lib.rs
@@ -1,11 +1,16 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
 extern crate memmap;
+extern crate rustc_demangle;
 extern crate thin_vec;
 extern crate uuid;
 
-#[cfg(feature = "parse_elf")]
-extern crate object;
 #[cfg(feature = "parse_elf")]
 extern crate goblin;
+#[cfg(feature = "parse_elf")]
+extern crate object;
 
 mod compact_symbol_table;
 
@@ -17,14 +22,17 @@ use memmap::MmapOptions;
 #[cfg(feature = "parse_elf")]
 use std::fs::File;
 
-use std::ffi::CStr;
-use std::os::raw::c_char;
 use compact_symbol_table::CompactSymbolTable;
+use rustc_demangle::try_demangle;
+use std::ffi::CStr;
+use std::mem;
+use std::os::raw::c_char;
+use std::ptr;
 
 #[cfg(feature = "parse_elf")]
 pub fn get_compact_symbol_table_from_file(
     debug_path: &str,
-    breakpad_id: &str,
+    breakpad_id: Option<&str>,
 ) -> Option<CompactSymbolTable> {
     let file = File::open(debug_path).ok()?;
     let buffer = unsafe { MmapOptions::new().map(&file).ok()? };
@@ -34,7 +42,7 @@ pub fn get_compact_symbol_table_from_file(
 #[cfg(not(feature = "parse_elf"))]
 pub fn get_compact_symbol_table_from_file(
     _debug_path: &str,
-    _breakpad_id: &str,
+    _breakpad_id: Option<&str>,
 ) -> Option<CompactSymbolTable> {
     None
 }
@@ -46,9 +54,16 @@ pub extern "C" fn profiler_get_symbol_table(
     symbol_table: &mut CompactSymbolTable,
 ) -> bool {
     let debug_path = unsafe { CStr::from_ptr(debug_path).to_string_lossy() };
-    let breakpad_id = unsafe { CStr::from_ptr(breakpad_id).to_string_lossy() };
+    let breakpad_id = if breakpad_id.is_null() {
+        None
+    } else {
+        match unsafe { CStr::from_ptr(breakpad_id).to_str() } {
+            Ok(s) => Some(s),
+            Err(_) => return false,
+        }
+    };
 
-    match get_compact_symbol_table_from_file(&debug_path, &breakpad_id) {
+    match get_compact_symbol_table_from_file(&debug_path, breakpad_id.map(|id| id.as_ref())) {
         Some(mut st) => {
             std::mem::swap(symbol_table, &mut st);
             true
@@ -56,3 +71,41 @@ pub extern "C" fn profiler_get_symbol_table(
         None => false,
     }
 }
+
+#[no_mangle]
+pub extern "C" fn profiler_demangle_rust(
+    mangled: *const c_char,
+    buffer: *mut c_char,
+    buffer_len: usize,
+) -> bool {
+    assert!(!mangled.is_null());
+    assert!(!buffer.is_null());
+
+    if buffer_len == 0 {
+        return false;
+    }
+
+    let buffer: *mut u8 = unsafe { mem::transmute(buffer) };
+    let mangled = match unsafe { CStr::from_ptr(mangled).to_str() } {
+        Ok(s) => s,
+        Err(_) => return false,
+    };
+
+    match try_demangle(mangled) {
+        Ok(demangled) => {
+            let mut demangled = format!("{:#}", demangled);
+            if !demangled.is_ascii() {
+                return false;
+            }
+            demangled.truncate(buffer_len - 1);
+
+            let bytes = demangled.as_bytes();
+            unsafe {
+                ptr::copy(bytes.as_ptr(), buffer, bytes.len());
+                ptr::write(buffer.offset(bytes.len() as isize), 0);
+            }
+            true
+        }
+        Err(_) => false,
+    }
+}
diff --git a/tools/profiler/tests/browser/browser.ini b/tools/profiler/tests/browser/browser.ini
index c0e22d88e2..f443b22829 100644
--- a/tools/profiler/tests/browser/browser.ini
+++ b/tools/profiler/tests/browser/browser.ini
@@ -8,6 +8,7 @@ support-files =
   single_frame_replacestate.html
 
 [browser_test_feature_jsallocations.js]
+[browser_test_feature_nativeallocations.js]
 [browser_test_profile_single_frame_page_info.js]
 [browser_test_profile_multi_frame_page_info.js]
 [browser_test_profile_pushstate_page_info.js]
diff --git a/tools/profiler/tests/browser/browser_test_feature_nativeallocations.js b/tools/profiler/tests/browser/browser_test_feature_nativeallocations.js
new file mode 100644
index 0000000000..0ce5f2b608
--- /dev/null
+++ b/tools/profiler/tests/browser/browser_test_feature_nativeallocations.js
@@ -0,0 +1,107 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * Test the native allocations feature. This is done as a browser test to ensure
+ * that we realistically try out how the native allocations are running. This
+ * ensures that we are collecting allocations for the content process and the
+ * parent process.
+ */
+add_task(async function test_profile_feature_nativeallocations() {
+  if (!AppConstants.MOZ_GECKO_PROFILER) {
+    return;
+  }
+  Assert.ok(
+    !Services.profiler.IsActive(),
+    "The profiler is not currently active"
+  );
+
+  info("Start the profiler to test the native allocations.");
+  startProfiler({
+    features: ["threads", "leaf", "nativeallocations"],
+  });
+
+  const env = Cc["@mozilla.org/process/environment;1"].getService(
+    Ci.nsIEnvironment
+  );
+
+  if (env.get("XPCOM_MEM_BLOAT_LOG")) {
+    info("Native allocations do not currently work with the bloat log.");
+    // Stop the profiler and exit. Note that this happens after we have already
+    // turned on the profiler so that we can still test this code path.
+    Services.profiler.StopProfiler();
+    return;
+  }
+
+  info("Launch a new tab to kick off a content process.");
+
+  const url = BASE_URL + "do_work_500ms.html";
+  await BrowserTestUtils.withNewTab(url, async contentBrowser => {
+    const contentPid = await ContentTask.spawn(
+      contentBrowser,
+      null,
+      () => Services.appinfo.processID
+    );
+
+    info("Wait 100ms so that we know some work has been done.");
+    await wait(100);
+
+    info(
+      "Check that we can get some allocations when the feature is turned on."
+    );
+    {
+      const { parentThread, contentThread } = await stopProfilerAndGetThreads(
+        contentPid
+      );
+      Assert.greater(
+        getPayloadsOfType(parentThread, "Native allocation").length,
+        0,
+        "Allocations were recorded for the parent process' main thread when the " +
+          "Native Allocation feature was turned on."
+      );
+      Assert.greater(
+        getPayloadsOfType(contentThread, "Native allocation").length,
+        0,
+        "Allocations were recorded for the content process' main thread when the " +
+          "Native Allocation feature was turned on."
+      );
+    }
+
+    info(
+      "Flush out any straggling allocation markers that may have not been " +
+        "collected yet by starting and stopping the profiler once."
+    );
+    startProfiler({ features: ["threads", "leaf"] });
+    await stopProfilerAndGetThreads(contentPid);
+
+    info("Now reload the tab with a clean run.");
+    gBrowser.reload();
+    await wait(100);
+    startProfiler({ features: ["threads", "leaf"] });
+
+    info(
+      "Check that no allocations were recorded, and allocation tracking was " +
+        "correctly turned off."
+    );
+
+    {
+      const { parentThread, contentThread } = await stopProfilerAndGetThreads(
+        contentPid
+      );
+      Assert.equal(
+        getPayloadsOfType(parentThread, "Native allocation").length,
+        0,
+        "No allocations were recorded for the parent processes' main thread when " +
+          "Native allocation was not turned on."
+      );
+
+      Assert.equal(
+        getPayloadsOfType(contentThread, "Native allocation").length,
+        0,
+        "No allocations were recorded for the content processes' main thread when " +
+          "Native allocation was not turned on."
+      );
+    }
+  });
+});
diff --git a/tools/profiler/tests/browser/browser_test_profile_multi_frame_page_info.js b/tools/profiler/tests/browser/browser_test_profile_multi_frame_page_info.js
index d20cb5652f..e989be168e 100644
--- a/tools/profiler/tests/browser/browser_test_profile_multi_frame_page_info.js
+++ b/tools/profiler/tests/browser/browser_test_profile_multi_frame_page_info.js
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-add_task(async function test_profile_single_frame_page_info() {
+add_task(async function test_profile_multi_frame_page_info() {
   if (!AppConstants.MOZ_GECKO_PROFILER) {
     return;
   }
@@ -11,7 +11,8 @@ add_task(async function test_profile_single_frame_page_info() {
   await Services.profiler.ClearAllPages();
   startProfiler();
 
-  const url = BASE_URL + "single_frame.html";
+  // multi_frame.html embeds single_frame.html inside an iframe.
+  const url = BASE_URL + "multi_frame.html";
   let contentPid;
   await BrowserTestUtils.withNewTab(url, async function(contentBrowser) {
     contentPid = await ContentTask.spawn(contentBrowser, null, () => {
@@ -22,20 +23,29 @@ add_task(async function test_profile_single_frame_page_info() {
   const profile = await Services.profiler.getProfileDataAsync();
   Services.profiler.StopProfiler();
 
-  let pageFound = false;
+  let foundPage = 0;
   // We need to find the correct content process for that tab.
   let contentProcess = profile.processes.find(
     p => p.threads[0].pid == contentPid
   );
   for (const page of contentProcess.pages) {
+    // Parent page
     if (page.url == url) {
       Assert.equal(page.url, url);
       Assert.equal(typeof page.docshellId, "string");
       Assert.equal(typeof page.historyId, "number");
       Assert.equal(page.isSubFrame, false);
-      pageFound = true;
-      break;
+      foundPage++;
+    }
+
+    // Child page (iframe)
+    if (page.url == BASE_URL + "single_frame.html") {
+      Assert.equal(page.url, BASE_URL + "single_frame.html");
+      Assert.equal(typeof page.docshellId, "string");
+      Assert.equal(typeof page.historyId, "number");
+      Assert.equal(page.isSubFrame, true);
+      foundPage++;
     }
   }
-  Assert.equal(pageFound, true);
+  Assert.equal(foundPage, 2);
 });
diff --git a/tools/profiler/tests/browser/browser_test_profile_single_frame_page_info.js b/tools/profiler/tests/browser/browser_test_profile_single_frame_page_info.js
index e989be168e..d20cb5652f 100644
--- a/tools/profiler/tests/browser/browser_test_profile_single_frame_page_info.js
+++ b/tools/profiler/tests/browser/browser_test_profile_single_frame_page_info.js
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-add_task(async function test_profile_multi_frame_page_info() {
+add_task(async function test_profile_single_frame_page_info() {
   if (!AppConstants.MOZ_GECKO_PROFILER) {
     return;
   }
@@ -11,8 +11,7 @@ add_task(async function test_profile_multi_frame_page_info() {
   await Services.profiler.ClearAllPages();
   startProfiler();
 
-  // multi_frame.html embeds single_frame.html inside an iframe.
-  const url = BASE_URL + "multi_frame.html";
+  const url = BASE_URL + "single_frame.html";
   let contentPid;
   await BrowserTestUtils.withNewTab(url, async function(contentBrowser) {
     contentPid = await ContentTask.spawn(contentBrowser, null, () => {
@@ -23,29 +22,20 @@ add_task(async function test_profile_multi_frame_page_info() {
   const profile = await Services.profiler.getProfileDataAsync();
   Services.profiler.StopProfiler();
 
-  let foundPage = 0;
+  let pageFound = false;
   // We need to find the correct content process for that tab.
   let contentProcess = profile.processes.find(
     p => p.threads[0].pid == contentPid
   );
   for (const page of contentProcess.pages) {
-    // Parent page
     if (page.url == url) {
       Assert.equal(page.url, url);
       Assert.equal(typeof page.docshellId, "string");
       Assert.equal(typeof page.historyId, "number");
       Assert.equal(page.isSubFrame, false);
-      foundPage++;
-    }
-
-    // Child page (iframe)
-    if (page.url == BASE_URL + "single_frame.html") {
-      Assert.equal(page.url, BASE_URL + "single_frame.html");
-      Assert.equal(typeof page.docshellId, "string");
-      Assert.equal(typeof page.historyId, "number");
-      Assert.equal(page.isSubFrame, true);
-      foundPage++;
+      pageFound = true;
+      break;
     }
   }
-  Assert.equal(foundPage, 2);
+  Assert.equal(pageFound, true);
 });
diff --git a/tools/profiler/tests/browser/head.js b/tools/profiler/tests/browser/head.js
index 0c1e823652..37f63e22d9 100644
--- a/tools/profiler/tests/browser/head.js
+++ b/tools/profiler/tests/browser/head.js
@@ -17,9 +17,7 @@ function startProfiler(callersSettings) {
     settings.entries,
     settings.interval,
     settings.features,
-    settings.features.length,
     settings.threads,
-    settings.threads.length,
     settings.duration
   );
 }
diff --git a/tools/profiler/tests/chrome/profiler_test_utils.js b/tools/profiler/tests/chrome/profiler_test_utils.js
index 9ae926a26f..7068b0f2d8 100644
--- a/tools/profiler/tests/chrome/profiler_test_utils.js
+++ b/tools/profiler/tests/chrome/profiler_test_utils.js
@@ -10,9 +10,7 @@
       settings.entries,
       settings.interval,
       settings.features,
-      settings.features.length,
       settings.threads,
-      settings.threads.length,
       settings.duration
     );
 
diff --git a/tools/profiler/tests/gtest/GeckoProfiler.cpp b/tools/profiler/tests/gtest/GeckoProfiler.cpp
index c4464e5b82..18b90c6ae5 100644
--- a/tools/profiler/tests/gtest/GeckoProfiler.cpp
+++ b/tools/profiler/tests/gtest/GeckoProfiler.cpp
@@ -14,7 +14,9 @@
 #include "ProfilerMarkerPayload.h"
 
 #include "js/Initialization.h"
+#include "js/Printf.h"
 #include "jsapi.h"
+#include "mozilla/BlocksRingBufferGeckoExtensions.h"
 #include "mozilla/UniquePtrExtensions.h"
 #include "nsIThread.h"
 #include "nsThreadUtils.h"
@@ -29,6 +31,53 @@
 
 using namespace mozilla;
 
+TEST(BaseProfiler, BlocksRingBuffer)
+{
+  constexpr uint32_t MBSize = 256;
+  uint8_t buffer[MBSize * 3];
+  for (size_t i = 0; i < MBSize * 3; ++i) {
+    buffer[i] = uint8_t('A' + i);
+  }
+  BlocksRingBuffer rb(BlocksRingBuffer::ThreadSafety::WithMutex,
+                      &buffer[MBSize], MakePowerOfTwo32<MBSize>());
+
+  {
+    nsCString cs(NS_LITERAL_CSTRING("nsCString"));
+    nsString s(NS_LITERAL_STRING("nsString"));
+    nsAutoCString acs(NS_LITERAL_CSTRING("nsAutoCString"));
+    nsAutoString as(NS_LITERAL_STRING("nsAutoString"));
+    nsAutoCStringN<8> acs8(NS_LITERAL_CSTRING("nsAutoCStringN"));
+    nsAutoStringN<8> as8(NS_LITERAL_STRING("nsAutoStringN"));
+    JS::UniqueChars jsuc = JS_smprintf("%s", "JS::UniqueChars");
+
+    rb.PutObjects(cs, s, acs, as, acs8, as8, jsuc);
+  }
+
+  rb.ReadEach([](BlocksRingBuffer::EntryReader& aER) {
+    ASSERT_EQ(aER.ReadObject<nsCString>(), NS_LITERAL_CSTRING("nsCString"));
+    ASSERT_EQ(aER.ReadObject<nsString>(), NS_LITERAL_STRING("nsString"));
+    ASSERT_EQ(aER.ReadObject<nsAutoCString>(),
+              NS_LITERAL_CSTRING("nsAutoCString"));
+    ASSERT_EQ(aER.ReadObject<nsAutoString>(),
+              NS_LITERAL_STRING("nsAutoString"));
+    ASSERT_EQ(aER.ReadObject<nsAutoCStringN<8>>(),
+              NS_LITERAL_CSTRING("nsAutoCStringN"));
+    ASSERT_EQ(aER.ReadObject<nsAutoStringN<8>>(),
+              NS_LITERAL_STRING("nsAutoStringN"));
+    auto jsuc2 = aER.ReadObject<JS::UniqueChars>();
+    ASSERT_TRUE(!!jsuc2);
+    ASSERT_TRUE(strcmp(jsuc2.get(), "JS::UniqueChars") == 0);
+  });
+
+  // Everything around the sub-buffer should be unchanged.
+  for (size_t i = 0; i < MBSize; ++i) {
+    ASSERT_EQ(buffer[i], uint8_t('A' + i));
+  }
+  for (size_t i = MBSize * 2; i < MBSize * 3; ++i) {
+    ASSERT_EQ(buffer[i], uint8_t('A' + i));
+  }
+}
+
 typedef Vector<const char*> StrVec;
 
 static void InactiveFeaturesAndParamsCheck() {
@@ -92,9 +141,9 @@ TEST(GeckoProfiler, FeaturesAndParams)
     ASSERT_TRUE(!profiler_feature_active(ProfilerFeature::MainThreadIO));
     ASSERT_TRUE(!profiler_feature_active(ProfilerFeature::Privacy));
 
-    ActiveParamsCheck(PROFILER_DEFAULT_ENTRIES, PROFILER_DEFAULT_INTERVAL,
-                      features, filters, MOZ_ARRAY_LENGTH(filters),
-                      Some(PROFILER_DEFAULT_DURATION));
+    ActiveParamsCheck(
+        PROFILER_DEFAULT_ENTRIES.Value(), PROFILER_DEFAULT_INTERVAL, features,
+        filters, MOZ_ARRAY_LENGTH(filters), Some(PROFILER_DEFAULT_DURATION));
 
     profiler_stop();
 
@@ -107,15 +156,18 @@ TEST(GeckoProfiler, FeaturesAndParams)
         ProfilerFeature::MainThreadIO | ProfilerFeature::Privacy;
     const char* filters[] = {"GeckoMain", "Foo", "Bar"};
 
-    profiler_start(999999, 3, features, filters, MOZ_ARRAY_LENGTH(filters),
-                   Some(25.0));
+    // Testing with some arbitrary buffer size (as could be provided by
+    // external code), which we convert to the appropriate power of 2.
+    profiler_start(PowerOfTwo32(999999), 3, features, filters,
+                   MOZ_ARRAY_LENGTH(filters), Some(25.0));
 
     ASSERT_TRUE(profiler_is_active());
     ASSERT_TRUE(profiler_feature_active(ProfilerFeature::MainThreadIO));
     ASSERT_TRUE(profiler_feature_active(ProfilerFeature::Privacy));
 
     // Profiler::Threads is added because filters has multiple entries.
-    ActiveParamsCheck(999999, 3, features | ProfilerFeature::Threads, filters,
+    ActiveParamsCheck(PowerOfTwo32(999999).Value(), 3,
+                      features | ProfilerFeature::Threads, filters,
                       MOZ_ARRAY_LENGTH(filters), Some(25.0));
 
     profiler_stop();
@@ -129,15 +181,16 @@ TEST(GeckoProfiler, FeaturesAndParams)
         ProfilerFeature::MainThreadIO | ProfilerFeature::Privacy;
     const char* filters[] = {"GeckoMain", "Foo", "Bar"};
 
-    profiler_start(999999, 3, features, filters, MOZ_ARRAY_LENGTH(filters),
-                   Nothing());
+    profiler_start(PowerOfTwo32(999999), 3, features, filters,
+                   MOZ_ARRAY_LENGTH(filters), Nothing());
 
     ASSERT_TRUE(profiler_is_active());
     ASSERT_TRUE(profiler_feature_active(ProfilerFeature::MainThreadIO));
     ASSERT_TRUE(profiler_feature_active(ProfilerFeature::Privacy));
 
     // Profiler::Threads is added because filters has multiple entries.
-    ActiveParamsCheck(999999, 3, features | ProfilerFeature::Threads, filters,
+    ActiveParamsCheck(PowerOfTwo32(999999).Value(), 3,
+                      features | ProfilerFeature::Threads, filters,
                       MOZ_ARRAY_LENGTH(filters), Nothing());
 
     profiler_stop();
@@ -150,15 +203,15 @@ TEST(GeckoProfiler, FeaturesAndParams)
     uint32_t availableFeatures = profiler_get_available_features();
     const char* filters[] = {""};
 
-    profiler_start(88888, 10, availableFeatures, filters,
+    profiler_start(PowerOfTwo32(88888), 10, availableFeatures, filters,
                    MOZ_ARRAY_LENGTH(filters), Some(15.0));
 
     ASSERT_TRUE(profiler_is_active());
     ASSERT_TRUE(profiler_feature_active(ProfilerFeature::MainThreadIO));
     ASSERT_TRUE(profiler_feature_active(ProfilerFeature::Privacy));
 
-    ActiveParamsCheck(88888, 10, availableFeatures, filters,
-                      MOZ_ARRAY_LENGTH(filters), Some(15.0));
+    ActiveParamsCheck(PowerOfTwo32(88888).Value(), 10, availableFeatures,
+                      filters, MOZ_ARRAY_LENGTH(filters), Some(15.0));
 
     // Don't call profiler_stop() here.
   }
@@ -170,15 +223,16 @@ TEST(GeckoProfiler, FeaturesAndParams)
 
     // Second profiler_start() call in a row without an intervening
     // profiler_stop(); this will do an implicit profiler_stop() and restart.
-    profiler_start(0, 0, features, filters, MOZ_ARRAY_LENGTH(filters),
-                   Some(0.0));
+    profiler_start(PowerOfTwo32(0), 0, features, filters,
+                   MOZ_ARRAY_LENGTH(filters), Some(0.0));
 
     ASSERT_TRUE(profiler_is_active());
     ASSERT_TRUE(!profiler_feature_active(ProfilerFeature::MainThreadIO));
     ASSERT_TRUE(!profiler_feature_active(ProfilerFeature::Privacy));
 
     // Entries and intervals go to defaults if 0 is specified.
-    ActiveParamsCheck(PROFILER_DEFAULT_ENTRIES, PROFILER_DEFAULT_INTERVAL,
+    ActiveParamsCheck(PROFILER_DEFAULT_ENTRIES.Value(),
+                      PROFILER_DEFAULT_INTERVAL,
                       features | ProfilerFeature::Threads, filters,
                       MOZ_ARRAY_LENGTH(filters), Nothing());
 
@@ -206,19 +260,22 @@ TEST(GeckoProfiler, EnsureStarted)
                             features, filters, MOZ_ARRAY_LENGTH(filters),
                             Some(PROFILER_DEFAULT_DURATION));
 
-    ActiveParamsCheck(PROFILER_DEFAULT_ENTRIES, PROFILER_DEFAULT_INTERVAL,
-                      features, filters, MOZ_ARRAY_LENGTH(filters),
-                      Some(PROFILER_DEFAULT_DURATION));
+    ActiveParamsCheck(
+        PROFILER_DEFAULT_ENTRIES.Value(), PROFILER_DEFAULT_INTERVAL, features,
+        filters, MOZ_ARRAY_LENGTH(filters), Some(PROFILER_DEFAULT_DURATION));
   }
 
   {
     // Active -> Active with same settings
 
+    Maybe<ProfilerBufferInfo> info0 = profiler_get_buffer_info();
+    ASSERT_TRUE(info0->mRangeEnd > 0);
+
     // First, write some samples into the buffer.
     PR_Sleep(PR_MillisecondsToInterval(500));
 
     Maybe<ProfilerBufferInfo> info1 = profiler_get_buffer_info();
-    ASSERT_TRUE(info1->mRangeEnd > 0);
+    ASSERT_TRUE(info1->mRangeEnd > info0->mRangeEnd);
 
     // Call profiler_ensure_started with the same settings as before.
     // This operation must not clear our buffer!
@@ -226,14 +283,18 @@ TEST(GeckoProfiler, EnsureStarted)
                             features, filters, MOZ_ARRAY_LENGTH(filters),
                             Some(PROFILER_DEFAULT_DURATION));
 
-    ActiveParamsCheck(PROFILER_DEFAULT_ENTRIES, PROFILER_DEFAULT_INTERVAL,
-                      features, filters, MOZ_ARRAY_LENGTH(filters),
-                      Some(PROFILER_DEFAULT_DURATION));
+    ActiveParamsCheck(
+        PROFILER_DEFAULT_ENTRIES.Value(), PROFILER_DEFAULT_INTERVAL, features,
+        filters, MOZ_ARRAY_LENGTH(filters), Some(PROFILER_DEFAULT_DURATION));
 
-    // Check that our position in the buffer stayed the same or advanced.
-    // In particular, it shouldn't have reverted to the start.
+    // Check that our position in the buffer stayed the same or advanced, but
+    // not by much, and the range-start after profiler_ensure_started shouldn't
+    // have passed the range-end before.
     Maybe<ProfilerBufferInfo> info2 = profiler_get_buffer_info();
     ASSERT_TRUE(info2->mRangeEnd >= info1->mRangeEnd);
+    ASSERT_TRUE(info2->mRangeEnd - info1->mRangeEnd <
+                info1->mRangeEnd - info0->mRangeEnd);
+    ASSERT_TRUE(info2->mRangeStart < info1->mRangeEnd);
   }
 
   {
@@ -249,11 +310,14 @@ TEST(GeckoProfiler, EnsureStarted)
                             differentFeatures, filters,
                             MOZ_ARRAY_LENGTH(filters));
 
-    ActiveParamsCheck(PROFILER_DEFAULT_ENTRIES, PROFILER_DEFAULT_INTERVAL,
-                      differentFeatures, filters, MOZ_ARRAY_LENGTH(filters));
+    ActiveParamsCheck(PROFILER_DEFAULT_ENTRIES.Value(),
+                      PROFILER_DEFAULT_INTERVAL, differentFeatures, filters,
+                      MOZ_ARRAY_LENGTH(filters));
 
+    // Check the the buffer was cleared, so its range-start should be at/after
+    // its range-end before.
     Maybe<ProfilerBufferInfo> info2 = profiler_get_buffer_info();
-    ASSERT_TRUE(info2->mRangeEnd < info1->mRangeEnd);
+    ASSERT_TRUE(info2->mRangeStart >= info1->mRangeEnd);
   }
 
   {
@@ -292,8 +356,9 @@ TEST(GeckoProfiler, DifferentThreads)
     ASSERT_TRUE(!profiler_feature_active(ProfilerFeature::MainThreadIO));
     ASSERT_TRUE(!profiler_feature_active(ProfilerFeature::Privacy));
 
-    ActiveParamsCheck(PROFILER_DEFAULT_ENTRIES, PROFILER_DEFAULT_INTERVAL,
-                      features, filters, MOZ_ARRAY_LENGTH(filters));
+    ActiveParamsCheck(PROFILER_DEFAULT_ENTRIES.Value(),
+                      PROFILER_DEFAULT_INTERVAL, features, filters,
+                      MOZ_ARRAY_LENGTH(filters));
 
     thread->Dispatch(
         NS_NewRunnableFunction("GeckoProfiler_DifferentThreads_Test::TestBody",
@@ -321,7 +386,7 @@ TEST(GeckoProfiler, DifferentThreads)
                   !profiler_feature_active(ProfilerFeature::MainThreadIO));
               ASSERT_TRUE(!profiler_feature_active(ProfilerFeature::Privacy));
 
-              ActiveParamsCheck(PROFILER_DEFAULT_ENTRIES,
+              ActiveParamsCheck(PROFILER_DEFAULT_ENTRIES.Value(),
                                 PROFILER_DEFAULT_INTERVAL, features, filters,
                                 MOZ_ARRAY_LENGTH(filters));
             }),
@@ -391,11 +456,13 @@ TEST(GeckoProfiler, Pause)
   const char* filters[] = {"GeckoMain"};
 
   ASSERT_TRUE(!profiler_is_paused());
+  ASSERT_TRUE(!profiler_can_accept_markers());
 
   profiler_start(PROFILER_DEFAULT_ENTRIES, PROFILER_DEFAULT_INTERVAL, features,
                  filters, MOZ_ARRAY_LENGTH(filters));
 
   ASSERT_TRUE(!profiler_is_paused());
+  ASSERT_TRUE(profiler_can_accept_markers());
 
   // Check that we are writing samples while not paused.
   Maybe<ProfilerBufferInfo> info1 = profiler_get_buffer_info();
@@ -403,9 +470,16 @@ TEST(GeckoProfiler, Pause)
   Maybe<ProfilerBufferInfo> info2 = profiler_get_buffer_info();
   ASSERT_TRUE(info1->mRangeEnd != info2->mRangeEnd);
 
+  // Check that we are writing markers while not paused.
+  info1 = profiler_get_buffer_info();
+  PROFILER_ADD_MARKER("Not paused", OTHER);
+  info2 = profiler_get_buffer_info();
+  ASSERT_TRUE(info1->mRangeEnd != info2->mRangeEnd);
+
   profiler_pause();
 
   ASSERT_TRUE(profiler_is_paused());
+  ASSERT_TRUE(!profiler_can_accept_markers());
 
   // Check that we are not writing samples while paused.
   info1 = profiler_get_buffer_info();
@@ -413,48 +487,89 @@ TEST(GeckoProfiler, Pause)
   info2 = profiler_get_buffer_info();
   ASSERT_TRUE(info1->mRangeEnd == info2->mRangeEnd);
 
+  // Check that we are now writing markers while paused.
+  info1 = profiler_get_buffer_info();
+  PROFILER_ADD_MARKER("Paused", OTHER);
+  info2 = profiler_get_buffer_info();
+  ASSERT_TRUE(info1->mRangeEnd == info2->mRangeEnd);
+
   profiler_resume();
 
   ASSERT_TRUE(!profiler_is_paused());
+  ASSERT_TRUE(profiler_can_accept_markers());
 
   profiler_stop();
 
   ASSERT_TRUE(!profiler_is_paused());
+  ASSERT_TRUE(!profiler_can_accept_markers());
 }
 
 // A class that keeps track of how many instances have been created, streamed,
 // and destroyed.
 class GTestMarkerPayload : public ProfilerMarkerPayload {
  public:
-  explicit GTestMarkerPayload(int aN) : mN(aN) { sNumCreated++; }
+  explicit GTestMarkerPayload(int aN) : mN(aN) { ++sNumCreated; }
 
-  virtual ~GTestMarkerPayload() { sNumDestroyed++; }
+  virtual ~GTestMarkerPayload() { ++sNumDestroyed; }
 
-  virtual void StreamPayload(SpliceableJSONWriter& aWriter,
-                             const mozilla::TimeStamp& aStartTime,
-                             UniqueStacks& aUniqueStacks) override {
-    StreamCommonProps("gtest", aWriter, aStartTime, aUniqueStacks);
-    char buf[64];
-    SprintfLiteral(buf, "gtest-%d", mN);
-    aWriter.IntProperty(buf, mN);
-    sNumStreamed++;
-  }
+  DECL_STREAM_PAYLOAD
 
  private:
+  GTestMarkerPayload(CommonProps&& aCommonProps, int aN)
+      : ProfilerMarkerPayload(std::move(aCommonProps)), mN(aN) {
+    ++sNumDeserialized;
+  }
+
   int mN;
 
  public:
   // The number of GTestMarkerPayload instances that have been created,
   // streamed, and destroyed.
   static int sNumCreated;
+  static int sNumSerialized;
+  static int sNumDeserialized;
   static int sNumStreamed;
   static int sNumDestroyed;
 };
 
 int GTestMarkerPayload::sNumCreated = 0;
+int GTestMarkerPayload::sNumSerialized = 0;
+int GTestMarkerPayload::sNumDeserialized = 0;
 int GTestMarkerPayload::sNumStreamed = 0;
 int GTestMarkerPayload::sNumDestroyed = 0;
 
+BlocksRingBuffer::Length GTestMarkerPayload::TagAndSerializationBytes() const {
+  return CommonPropsTagAndSerializationBytes() + BlocksRingBuffer::SumBytes(mN);
+}
+
+void GTestMarkerPayload::SerializeTagAndPayload(
+    BlocksRingBuffer::EntryWriter& aEntryWriter) const {
+  static const DeserializerTag tag = TagForDeserializer(Deserialize);
+  SerializeTagAndCommonProps(tag, aEntryWriter);
+  aEntryWriter.WriteObject(mN);
+  ++sNumSerialized;
+}
+
+// static
+UniquePtr<ProfilerMarkerPayload> GTestMarkerPayload::Deserialize(
+    BlocksRingBuffer::EntryReader& aEntryReader) {
+  ProfilerMarkerPayload::CommonProps props =
+      DeserializeCommonProps(aEntryReader);
+  auto n = aEntryReader.ReadObject<int>();
+  return UniquePtr<ProfilerMarkerPayload>(
+      new GTestMarkerPayload(std::move(props), n));
+}
+
+void GTestMarkerPayload::StreamPayload(SpliceableJSONWriter& aWriter,
+                                       const mozilla::TimeStamp& aStartTime,
+                                       UniqueStacks& aUniqueStacks) const {
+  StreamCommonProps("gtest", aWriter, aStartTime, aUniqueStacks);
+  char buf[64];
+  SprintfLiteral(buf, "gtest-%d", mN);
+  aWriter.IntProperty(buf, mN);
+  ++sNumStreamed;
+}
+
 TEST(GeckoProfiler, Markers)
 {
   uint32_t features = ProfilerFeature::StackWalk;
@@ -473,19 +588,25 @@ TEST(GeckoProfiler, Markers)
 
   { AUTO_PROFILER_TRACING("C", "A", OTHER); }
 
-  profiler_add_marker("M1", JS::ProfilingCategoryPair::OTHER);
-  profiler_add_marker("M2", JS::ProfilingCategoryPair::OTHER,
-                      MakeUnique<TracingMarkerPayload>("C", TRACING_EVENT));
+  PROFILER_ADD_MARKER("M1", OTHER);
+  PROFILER_ADD_MARKER_WITH_PAYLOAD("M2", OTHER, TracingMarkerPayload,
+                                   ("C", TRACING_EVENT));
   PROFILER_ADD_MARKER("M3", OTHER);
-  profiler_add_marker("M4", JS::ProfilingCategoryPair::OTHER,
-                      MakeUnique<TracingMarkerPayload>(
-                          "C", TRACING_EVENT, mozilla::Nothing(),
-                          mozilla::Nothing(), profiler_get_backtrace()));
+  PROFILER_ADD_MARKER_WITH_PAYLOAD(
+      "M4", OTHER, TracingMarkerPayload,
+      ("C", TRACING_EVENT, mozilla::Nothing(), mozilla::Nothing(),
+       profiler_get_backtrace()));
 
   for (int i = 0; i < 10; i++) {
-    profiler_add_marker("M5", JS::ProfilingCategoryPair::OTHER,
-                        MakeUnique<GTestMarkerPayload>(i));
+    PROFILER_ADD_MARKER_WITH_PAYLOAD("M5", OTHER, GTestMarkerPayload, (i));
   }
+  // The GTestMarkerPayloads should have been created, serialized, and
+  // destroyed.
+  ASSERT_EQ(GTestMarkerPayload::sNumCreated, 10);
+  ASSERT_EQ(GTestMarkerPayload::sNumSerialized, 10);
+  ASSERT_EQ(GTestMarkerPayload::sNumDeserialized, 0);
+  ASSERT_EQ(GTestMarkerPayload::sNumStreamed, 0);
+  ASSERT_EQ(GTestMarkerPayload::sNumDestroyed, 10);
 
   // Create two strings: one that is the maximum allowed length, and one that
   // is one char longer.
@@ -514,11 +635,13 @@ TEST(GeckoProfiler, Markers)
 
   UniquePtr<char[]> profile = w.WriteFunc()->CopyData();
 
-  // The GTestMarkerPayloads should have been created and streamed, but not yet
+  // The GTestMarkerPayloads should have been deserialized, streamed, and
   // destroyed.
-  ASSERT_TRUE(GTestMarkerPayload::sNumCreated == 10);
-  ASSERT_TRUE(GTestMarkerPayload::sNumStreamed == 10);
-  ASSERT_TRUE(GTestMarkerPayload::sNumDestroyed == 0);
+  ASSERT_EQ(GTestMarkerPayload::sNumCreated, 10 + 0);
+  ASSERT_EQ(GTestMarkerPayload::sNumSerialized, 10 + 0);
+  ASSERT_EQ(GTestMarkerPayload::sNumDeserialized, 0 + 10);
+  ASSERT_EQ(GTestMarkerPayload::sNumStreamed, 0 + 10);
+  ASSERT_EQ(GTestMarkerPayload::sNumDestroyed, 10 + 10);
   for (int i = 0; i < 10; i++) {
     char buf[64];
     SprintfLiteral(buf, "\"gtest-%d\"", i);
@@ -536,14 +659,46 @@ TEST(GeckoProfiler, Markers)
   ASSERT_TRUE(!strstr(profile.get(), longstr.get()));
   ASSERT_TRUE(strstr(profile.get(), "(too long)"));
 
+  Maybe<ProfilerBufferInfo> info = profiler_get_buffer_info();
+  MOZ_RELEASE_ASSERT(info.isSome());
+  printf("Profiler buffer range: %llu .. %llu (%llu bytes)\n",
+         static_cast<unsigned long long>(info->mRangeStart),
+         static_cast<unsigned long long>(info->mRangeEnd),
+         // sizeof(ProfileBufferEntry) == 9
+         (static_cast<unsigned long long>(info->mRangeEnd) -
+          static_cast<unsigned long long>(info->mRangeStart)) *
+             9);
+  printf("Stats:         min(ns) .. mean(ns) .. max(ns)  [count]\n");
+  printf("- Intervals:   %7.1f .. %7.1f  .. %7.1f  [%u]\n",
+         info->mIntervalsNs.min, info->mIntervalsNs.sum / info->mIntervalsNs.n,
+         info->mIntervalsNs.max, info->mIntervalsNs.n);
+  printf("- Overheads:   %7.1f .. %7.1f  .. %7.1f  [%u]\n",
+         info->mOverheadsNs.min, info->mOverheadsNs.sum / info->mOverheadsNs.n,
+         info->mOverheadsNs.max, info->mOverheadsNs.n);
+  printf("  - Locking:   %7.1f .. %7.1f  .. %7.1f  [%u]\n",
+         info->mLockingsNs.min, info->mLockingsNs.sum / info->mLockingsNs.n,
+         info->mLockingsNs.max, info->mLockingsNs.n);
+  printf("  - Clearning: %7.1f .. %7.1f  .. %7.1f  [%u]\n",
+         info->mCleaningsNs.min, info->mCleaningsNs.sum / info->mCleaningsNs.n,
+         info->mCleaningsNs.max, info->mCleaningsNs.n);
+  printf("  - Counters:  %7.1f .. %7.1f  .. %7.1f  [%u]\n",
+         info->mCountersNs.min, info->mCountersNs.sum / info->mCountersNs.n,
+         info->mCountersNs.max, info->mCountersNs.n);
+  printf("  - Threads:   %7.1f .. %7.1f  .. %7.1f  [%u]\n",
+         info->mThreadsNs.min, info->mThreadsNs.sum / info->mThreadsNs.n,
+         info->mThreadsNs.max, info->mThreadsNs.n);
+
   profiler_stop();
 
-  // The GTestMarkerPayloads should have been destroyed.
-  ASSERT_TRUE(GTestMarkerPayload::sNumDestroyed == 10);
+  // Nothing more should have happened to the GTestMarkerPayloads.
+  ASSERT_EQ(GTestMarkerPayload::sNumCreated, 10 + 0 + 0);
+  ASSERT_EQ(GTestMarkerPayload::sNumSerialized, 10 + 0 + 0);
+  ASSERT_EQ(GTestMarkerPayload::sNumDeserialized, 0 + 10 + 0);
+  ASSERT_EQ(GTestMarkerPayload::sNumStreamed, 0 + 10 + 0);
+  ASSERT_EQ(GTestMarkerPayload::sNumDestroyed, 10 + 10 + 0);
 
   for (int i = 0; i < 10; i++) {
-    profiler_add_marker("M5", JS::ProfilingCategoryPair::OTHER,
-                        MakeUnique<GTestMarkerPayload>(i));
+    PROFILER_ADD_MARKER_WITH_PAYLOAD("M5", OTHER, GTestMarkerPayload, (i));
   }
 
   // Warning: this could be racy
@@ -554,10 +709,13 @@ TEST(GeckoProfiler, Markers)
 
   profiler_stop();
 
-  // The second set of GTestMarkerPayloads should not have been streamed.
-  ASSERT_TRUE(GTestMarkerPayload::sNumCreated == 20);
-  ASSERT_TRUE(GTestMarkerPayload::sNumStreamed == 10);
-  ASSERT_TRUE(GTestMarkerPayload::sNumDestroyed == 20);
+  // The second set of GTestMarkerPayloads should not have been serialized or
+  // streamed.
+  ASSERT_EQ(GTestMarkerPayload::sNumCreated, 10 + 0 + 0 + 10);
+  ASSERT_EQ(GTestMarkerPayload::sNumSerialized, 10 + 0 + 0 + 0);
+  ASSERT_EQ(GTestMarkerPayload::sNumDeserialized, 0 + 10 + 0 + 0);
+  ASSERT_EQ(GTestMarkerPayload::sNumStreamed, 0 + 10 + 0 + 0);
+  ASSERT_EQ(GTestMarkerPayload::sNumDestroyed, 10 + 10 + 0 + 10);
 }
 
 TEST(GeckoProfiler, DurationLimit)
@@ -570,23 +728,26 @@ TEST(GeckoProfiler, DurationLimit)
 
   // Clear up the counters after the last test.
   GTestMarkerPayload::sNumCreated = 0;
+  GTestMarkerPayload::sNumSerialized = 0;
+  GTestMarkerPayload::sNumDeserialized = 0;
   GTestMarkerPayload::sNumStreamed = 0;
   GTestMarkerPayload::sNumDestroyed = 0;
 
-  profiler_add_marker("M1", JS::ProfilingCategoryPair::OTHER,
-                      MakeUnique<GTestMarkerPayload>(1));
+  PROFILER_ADD_MARKER_WITH_PAYLOAD("M1", OTHER, GTestMarkerPayload, (1));
   PR_Sleep(PR_MillisecondsToInterval(1100));
-  profiler_add_marker("M2", JS::ProfilingCategoryPair::OTHER,
-                      MakeUnique<GTestMarkerPayload>(2));
+  PROFILER_ADD_MARKER_WITH_PAYLOAD("M2", OTHER, GTestMarkerPayload, (2));
   PR_Sleep(PR_MillisecondsToInterval(500));
 
   SpliceableChunkedJSONWriter w;
   ASSERT_TRUE(profiler_stream_json_for_this_process(w));
 
-  // The first marker should be destroyed.
-  ASSERT_TRUE(GTestMarkerPayload::sNumCreated == 2);
-  ASSERT_TRUE(GTestMarkerPayload::sNumStreamed == 1);
-  ASSERT_TRUE(GTestMarkerPayload::sNumDestroyed == 1);
+  // Both markers created, serialized, destroyed; Only the first marker should
+  // have been deserialized, streamed, and destroyed again.
+  ASSERT_EQ(GTestMarkerPayload::sNumCreated, 2);
+  ASSERT_EQ(GTestMarkerPayload::sNumSerialized, 2);
+  ASSERT_EQ(GTestMarkerPayload::sNumDeserialized, 1);
+  ASSERT_EQ(GTestMarkerPayload::sNumStreamed, 1);
+  ASSERT_EQ(GTestMarkerPayload::sNumDestroyed, 3);
 }
 
 #define COUNTER_NAME "TestCounter"
diff --git a/tools/profiler/tests/gtest/ThreadProfileTest.cpp b/tools/profiler/tests/gtest/ThreadProfileTest.cpp
index 745e3a4918..17f3a8da56 100644
--- a/tools/profiler/tests/gtest/ThreadProfileTest.cpp
+++ b/tools/profiler/tests/gtest/ThreadProfileTest.cpp
@@ -5,51 +5,47 @@
 #include "ProfileBufferEntry.h"
 #include "ThreadInfo.h"
 
+#include "mozilla/PowerOfTwo.h"
+
 #include "gtest/gtest.h"
 
 // Make sure we can record one entry and read it
 TEST(ThreadProfile, InsertOneEntry)
 {
-  auto pb = MakeUnique<ProfileBuffer>(10);
+  mozilla::BlocksRingBuffer blocksRingBuffer(
+      BlocksRingBuffer::ThreadSafety::WithMutex);
+  auto pb = MakeUnique<ProfileBuffer>(
+      blocksRingBuffer,
+      mozilla::PowerOfTwo32(2 * (1 + uint32_t(sizeof(ProfileBufferEntry)))));
   pb->AddEntry(ProfileBufferEntry::Time(123.1));
-  ASSERT_TRUE(pb->GetEntry(pb->mRangeStart).IsTime());
-  ASSERT_TRUE(pb->GetEntry(pb->mRangeStart).GetDouble() == 123.1);
+  ProfileBufferEntry entry = pb->GetEntry(pb->BufferRangeStart());
+  ASSERT_TRUE(entry.IsTime());
+  ASSERT_EQ(123.1, entry.GetDouble());
 }
 
 // See if we can insert some entries
 TEST(ThreadProfile, InsertEntriesNoWrap)
 {
-  auto pb = MakeUnique<ProfileBuffer>(100);
-  int test_size = 50;
+  mozilla::BlocksRingBuffer blocksRingBuffer(
+      BlocksRingBuffer::ThreadSafety::WithMutex);
+  auto pb = MakeUnique<ProfileBuffer>(
+      blocksRingBuffer,
+      mozilla::PowerOfTwo32(100 * (1 + uint32_t(sizeof(ProfileBufferEntry)))));
+  const int test_size = 50;
   for (int i = 0; i < test_size; i++) {
     pb->AddEntry(ProfileBufferEntry::Time(i));
   }
-  uint64_t readPos = pb->mRangeStart;
-  while (readPos != pb->mRangeEnd) {
-    ASSERT_TRUE(pb->GetEntry(readPos).IsTime());
-    ASSERT_TRUE(pb->GetEntry(readPos).GetDouble() == readPos);
-    readPos++;
-  }
-}
-
-// See if evicting works as it should in the basic case
-TEST(ThreadProfile, InsertEntriesWrap)
-{
-  int entries = 32;
-  auto pb = MakeUnique<ProfileBuffer>(entries);
-  ASSERT_TRUE(pb->mRangeStart == 0);
-  ASSERT_TRUE(pb->mRangeEnd == 0);
-  int test_size = 43;
-  for (int i = 0; i < test_size; i++) {
-    pb->AddEntry(ProfileBufferEntry::Time(i));
-  }
-  // We inserted 11 more entries than fit in the buffer, so the first 11 entries
-  // should have been evicted, and the range start should have increased to 11.
-  ASSERT_TRUE(pb->mRangeStart == 11);
-  uint64_t readPos = pb->mRangeStart;
-  while (readPos != pb->mRangeEnd) {
-    ASSERT_TRUE(pb->GetEntry(readPos).IsTime());
-    ASSERT_TRUE(pb->GetEntry(readPos).GetDouble() == readPos);
+  int times = 0;
+  uint64_t readPos = pb->BufferRangeStart();
+  while (readPos != pb->BufferRangeEnd()) {
+    ProfileBufferEntry entry = pb->GetEntry(readPos);
     readPos++;
+    if (entry.GetKind() == ProfileBufferEntry::Kind::INVALID) {
+      continue;
+    }
+    ASSERT_TRUE(entry.IsTime());
+    ASSERT_EQ(times, entry.GetDouble());
+    times++;
   }
+  ASSERT_EQ(test_size, times);
 }
diff --git a/tools/profiler/tests/xpcshell/test_asm.js b/tools/profiler/tests/xpcshell/test_asm.js
index ce555b0474..fe04782c0d 100644
--- a/tools/profiler/tests/xpcshell/test_asm.js
+++ b/tools/profiler/tests/xpcshell/test_asm.js
@@ -16,7 +16,7 @@ function run_test() {
   }
 
   const ms = 10;
-  Services.profiler.StartProfiler(10000, ms, ["js"], 1);
+  Services.profiler.StartProfiler(10000, ms, ["js"]);
 
   let stack = null;
   function ffi_function() {
diff --git a/tools/profiler/tests/xpcshell/test_enterjit_osr.js b/tools/profiler/tests/xpcshell/test_enterjit_osr.js
index df4451f352..87fc711138 100644
--- a/tools/profiler/tests/xpcshell/test_enterjit_osr.js
+++ b/tools/profiler/tests/xpcshell/test_enterjit_osr.js
@@ -12,7 +12,7 @@ function run_test() {
   Assert.ok(!Services.profiler.IsActive());
 
   const ms = 5;
-  Services.profiler.StartProfiler(10000, ms, ["js"], 1);
+  Services.profiler.StartProfiler(10000, ms, ["js"]);
 
   function has_arbitrary_name_in_stack() {
     // A frame for |arbitrary_name| has been pushed.  Do a sequence of
diff --git a/tools/profiler/tests/xpcshell/test_enterjit_osr_disabling.js b/tools/profiler/tests/xpcshell/test_enterjit_osr_disabling.js
index b1a898c459..2d4ffe5a10 100644
--- a/tools/profiler/tests/xpcshell/test_enterjit_osr_disabling.js
+++ b/tools/profiler/tests/xpcshell/test_enterjit_osr_disabling.js
@@ -6,7 +6,7 @@ function run_test() {
 
   Assert.ok(!Services.profiler.IsActive());
 
-  Services.profiler.StartProfiler(100, 10, ["js"], 1);
+  Services.profiler.StartProfiler(100, 10, ["js"]);
   // The function is entered with the profiler enabled
   (function() {
     Services.profiler.StopProfiler();
diff --git a/tools/profiler/tests/xpcshell/test_enterjit_osr_enabling.js b/tools/profiler/tests/xpcshell/test_enterjit_osr_enabling.js
index 4195ed7ee0..3084a00018 100644
--- a/tools/profiler/tests/xpcshell/test_enterjit_osr_enabling.js
+++ b/tools/profiler/tests/xpcshell/test_enterjit_osr_enabling.js
@@ -7,7 +7,7 @@ function run_test() {
 
   // The function is entered with the profiler disabled.
   (function() {
-    Services.profiler.StartProfiler(100, 10, ["js"], 1);
+    Services.profiler.StartProfiler(100, 10, ["js"]);
     let n = 10000;
     // eslint-disable-next-line no-empty
     while (--n) {} // OSR happens here with the profiler enabled.
diff --git a/tools/profiler/tests/xpcshell/test_feature_mainthreadio.js b/tools/profiler/tests/xpcshell/test_feature_mainthreadio.js
index 6c533c1908..f7d82917ab 100644
--- a/tools/profiler/tests/xpcshell/test_feature_mainthreadio.js
+++ b/tools/profiler/tests/xpcshell/test_feature_mainthreadio.js
@@ -86,9 +86,7 @@ async function startProfilerAndgetFileIOPayloads(features, filename) {
     entries,
     interval,
     features,
-    features.length,
     threads,
-    threads.length
   );
 
   const file = FileUtils.getFile("TmpD", [filename]);
diff --git a/tools/profiler/tests/xpcshell/test_get_features.js b/tools/profiler/tests/xpcshell/test_get_features.js
index 04d9732995..23aee089a3 100644
--- a/tools/profiler/tests/xpcshell/test_get_features.js
+++ b/tools/profiler/tests/xpcshell/test_get_features.js
@@ -7,6 +7,6 @@ function run_test() {
     return;
   }
 
-  var profilerFeatures = Services.profiler.GetFeatures([]);
+  var profilerFeatures = Services.profiler.GetFeatures();
   Assert.ok(profilerFeatures != null);
 }
diff --git a/tools/profiler/tests/xpcshell/test_pause.js b/tools/profiler/tests/xpcshell/test_pause.js
index 2c3b425629..dcda26359f 100644
--- a/tools/profiler/tests/xpcshell/test_pause.js
+++ b/tools/profiler/tests/xpcshell/test_pause.js
@@ -10,7 +10,7 @@ function run_test() {
   Assert.ok(!Services.profiler.IsActive());
   Assert.ok(!Services.profiler.IsPaused());
 
-  Services.profiler.StartProfiler(1000, 10, [], 0);
+  Services.profiler.StartProfiler(1000, 10, []);
 
   Assert.ok(Services.profiler.IsActive());
 
diff --git a/tools/profiler/tests/xpcshell/test_responsiveness.js b/tools/profiler/tests/xpcshell/test_responsiveness.js
new file mode 100644
index 0000000000..22cdac6c55
--- /dev/null
+++ b/tools/profiler/tests/xpcshell/test_responsiveness.js
@@ -0,0 +1,53 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * Test that we can measure non-zero event delays (responsiveness)
+ */
+
+add_task(async () => {
+  if (!AppConstants.MOZ_GECKO_PROFILER) {
+    return;
+  }
+  const entries = 10000;
+  const interval = 1;
+  const threads = [];
+  const features = [];
+
+  Services.profiler.StartProfiler(entries, interval, features, threads);
+
+  await functionA();
+
+  const profile = await Services.profiler.getProfileDataAsync();
+  const [thread] = profile.threads;
+  const { samples } = thread;
+  const message = "Responsiveness > 0 not found.";
+  let SAMPLE_STACK_SLOT = thread.samples.schema.responsiveness;
+
+  for (let i = 0; i < samples.data.length; i++) {
+    if (samples.data[i][SAMPLE_STACK_SLOT] > 0) {
+      Assert.ok(true, message);
+      return;
+    }
+  }
+  Assert.ok(false, message);
+});
+
+function doSyncWork(milliseconds) {
+  const start = Date.now();
+  while (true) {
+    this.n = 0;
+    for (let i = 0; i < 1e5; i++) {
+      this.n += Math.random();
+    }
+    if (Date.now() - start > milliseconds) {
+      return;
+    }
+  }
+}
+
+function functionA() {
+  doSyncWork(100);
+  doAtLeastOnePeriodicSample();
+}
diff --git a/tools/profiler/tests/xpcshell/test_run.js b/tools/profiler/tests/xpcshell/test_run.js
index d38c55da22..607c828677 100644
--- a/tools/profiler/tests/xpcshell/test_run.js
+++ b/tools/profiler/tests/xpcshell/test_run.js
@@ -9,7 +9,7 @@ function run_test() {
 
   Assert.ok(!Services.profiler.IsActive());
 
-  Services.profiler.StartProfiler(1000, 10, [], 0);
+  Services.profiler.StartProfiler(1000, 10, []);
 
   Assert.ok(Services.profiler.IsActive());
 
diff --git a/tools/profiler/tests/xpcshell/test_start.js b/tools/profiler/tests/xpcshell/test_start.js
index a6465d7b90..c220ba22eb 100644
--- a/tools/profiler/tests/xpcshell/test_start.js
+++ b/tools/profiler/tests/xpcshell/test_start.js
@@ -9,7 +9,7 @@ function run_test() {
 
   Assert.ok(!Services.profiler.IsActive());
 
-  Services.profiler.StartProfiler(10, 100, [], 0);
+  Services.profiler.StartProfiler(10, 100, []);
 
   Assert.ok(Services.profiler.IsActive());
 
diff --git a/tools/profiler/tests/xpcshell/xpcshell.ini b/tools/profiler/tests/xpcshell/xpcshell.ini
index ed1f385248..f079e0dc87 100644
--- a/tools/profiler/tests/xpcshell/xpcshell.ini
+++ b/tools/profiler/tests/xpcshell/xpcshell.ini
@@ -5,6 +5,7 @@ skip-if = toolkit == 'android'
 [test_start.js]
 skip-if = true
 [test_get_features.js]
+[test_responsiveness.js]
 [test_shared_library.js]
 [test_run.js]
 skip-if = true
diff --git a/tools/rewriting/ThirdPartyPaths.txt b/tools/rewriting/ThirdPartyPaths.txt
index 52ce74b1d1..106832a47f 100644
--- a/tools/rewriting/ThirdPartyPaths.txt
+++ b/tools/rewriting/ThirdPartyPaths.txt
@@ -1,10 +1,13 @@
 browser/components/translation/cld2/
-devtools/client/aboutdebugging-new/test/jest/node_modules/
+devtools/client/aboutdebugging/test/jest/node_modules/
 devtools/client/application/test/components/node_modules/
+devtools/client/debugger/flow-typed/npm/
 devtools/client/debugger/node_modules/
 devtools/client/shared/build/babel.js
 devtools/client/shared/sourceeditor/codemirror/
 devtools/client/shared/sourceeditor/tern/
+devtools/client/shared/vendor/
+devtools/shared/jsbeautify/
 devtools/shared/heapsnapshot/CoreDump.pb.cc
 devtools/shared/heapsnapshot/CoreDump.pb.h
 dom/canvas/test/webgl-conf/checkout/closure-library/
@@ -104,6 +107,7 @@ mozglue/misc/decimal/
 netwerk/dns/nsIDNKitInterface.h
 netwerk/sctp/src/
 netwerk/srtp/src/
+node_modules/
 nsprpub/
 other-licenses/
 parser/expat/
diff --git a/uriloader/exthandler/nsMIMEInfoImpl.cpp b/uriloader/exthandler/nsMIMEInfoImpl.cpp
index 02b7bab209..f0d58ed6d5 100644
--- a/uriloader/exthandler/nsMIMEInfoImpl.cpp
+++ b/uriloader/exthandler/nsMIMEInfoImpl.cpp
@@ -271,9 +271,7 @@ nsMIMEInfoBase::LaunchWithFile(nsIFile* aFile) {
 NS_IMETHODIMP
 nsMIMEInfoBase::LaunchWithURI(nsIURI* aURI,
                               nsIInterfaceRequestor* aWindowContext) {
-  // for now, this is only being called with protocol handlers; that
-  // will change once we get to more general registerContentHandler
-  // support
+  // This is only being called with protocol handlers
   NS_ASSERTION(mClass == eProtocolInfo,
                "nsMIMEInfoBase should be a protocol handler");
 
diff --git a/uriloader/exthandler/tests/mochitest/mochitest.ini b/uriloader/exthandler/tests/mochitest/mochitest.ini
index 062df2fac7..4d00ebc0e9 100644
--- a/uriloader/exthandler/tests/mochitest/mochitest.ini
+++ b/uriloader/exthandler/tests/mochitest/mochitest.ini
@@ -11,4 +11,3 @@ scheme = https
 [test_unknown_ext_protocol_handlers.html]
 [test_unsafeBidiChars.xhtml]
 skip-if = toolkit == 'android' && !is_fennec # Bug 1525959
-[test_web_protocol_handlers.html]
diff --git a/uriloader/exthandler/tests/mochitest/test_web_protocol_handlers.html b/uriloader/exthandler/tests/mochitest/test_web_protocol_handlers.html
deleted file mode 100644
index be773239bd..0000000000
--- a/uriloader/exthandler/tests/mochitest/test_web_protocol_handlers.html
+++ /dev/null
@@ -1,25 +0,0 @@
-<!DOCTYPE html>
-<html>
-<head>
-  <title>Test for disabled registerProtocolHandler</title>
-  <script src="/tests/SimpleTest/SimpleTest.js"></script>
-  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
-</head>
-<body>
-<p id="display"></p>
-<iframe id="test"></iframe>
-<script type="text/javascript">
-add_task(async function() {
-  await SpecialPowers.pushPrefEnv({
-    set: [
-      ["dom.registerContentHandler.enabled", true],
-      ["dom.registerProtocolHandler.insecure.enabled", false],
-    ],
-  });
-
-  let result = "registerProtocolHandler" in navigator;
-  ok(!result, "Insecure registerProtocolHandler is undefined");
-});
-</script>
-</body>
-</html>
diff --git a/widget/ProcInfo.h b/widget/ProcInfo.h
index 20ff7ee53f..9090192f02 100644
--- a/widget/ProcInfo.h
+++ b/widget/ProcInfo.h
@@ -11,6 +11,10 @@
 
 namespace mozilla {
 
+namespace ipc {
+class GeckoChildProcessHost;
+}
+
 // Process types
 enum class ProcType {
   // These must match the ones in ContentParent.h and E10SUtils.jsm
@@ -19,14 +23,16 @@ enum class ProcType {
   Extension,
   Privileged,
   WebLargeAllocation,
-  // GPU process (only on Windows)
-  Gpu,
-  // RDD process (Windows and macOS)
-  Rdd,
-  // Socket process
+  // the rest matches GeckoProcessTypes.h
+  Browser,  // Default is named Browser here
+  Plugin,
+  IPDLUnitTest,
+  GMPlugin,
+  GPU,
+  VR,
+  RDD,
   Socket,
-  // Main process
-  Browser,
+  RemoteSandboxBroker,
   // Unknown type of process
   Unknown
 };
@@ -71,8 +77,14 @@ typedef MozPromise<ProcInfo, nsresult, true> ProcInfoPromise;
  * Depending on the platform, this call can be quite expensive and the
  * promise may return after several ms.
  */
+#ifdef XP_MACOSX
+RefPtr<ProcInfoPromise> GetProcInfo(base::ProcessId pid, int32_t childId,
+                                    const ProcType& type,
+                                    mach_port_t aChildTask = MACH_PORT_NULL);
+#else
 RefPtr<ProcInfoPromise> GetProcInfo(base::ProcessId pid, int32_t childId,
                                     const ProcType& type);
+#endif
 
 }  // namespace mozilla
 #endif  // ProcInfo_h
diff --git a/widget/android/ANRReporter.cpp b/widget/android/ANRReporter.cpp
index dd7158e2c6..12ce631624 100644
--- a/widget/android/ANRReporter.cpp
+++ b/widget/android/ANRReporter.cpp
@@ -27,8 +27,8 @@ bool ANRReporter::RequestNativeStack(bool aUnwind) {
   const char* NATIVE_STACK_THREADS[] = {"GeckoMain", "Compositor"};
 
   // Buffer one sample and let the profiler wait a long time
-  profiler_start(/* entries */ 100, /* interval */ 10000, features,
-                 NATIVE_STACK_THREADS,
+  profiler_start(/* entries */ PowerOfTwo<uint32_t>(100), /* interval */ 10000,
+                 features, NATIVE_STACK_THREADS,
                  sizeof(NATIVE_STACK_THREADS) / sizeof(char*));
 #endif
   return true;
diff --git a/widget/android/EventDispatcher.cpp b/widget/android/EventDispatcher.cpp
index d8e96e5e57..8050c7b030 100644
--- a/widget/android/EventDispatcher.cpp
+++ b/widget/android/EventDispatcher.cpp
@@ -8,6 +8,7 @@
 #include "nsAppShell.h"
 #include "nsJSUtils.h"
 #include "js/Array.h"  // JS::GetArrayLength, JS::IsArrayObject, JS::NewArrayObject
+#include "js/String.h"    // JS::StringHasLatin1Chars
 #include "js/Warnings.h"  // JS::WarnUTF8
 #include "xpcpublic.h"
 
@@ -43,7 +44,7 @@ nsresult BoxString(JSContext* aCx, JS::HandleValue aData,
 
   JS::RootedString str(aCx, aData.toString());
 
-  if (JS_StringHasLatin1Chars(str)) {
+  if (JS::StringHasLatin1Chars(str)) {
     nsAutoJSString autoStr;
     NS_ENSURE_TRUE(CheckJS(aCx, autoStr.init(aCx, str)), NS_ERROR_FAILURE);
 
diff --git a/widget/android/ProcInfo.cpp b/widget/android/ProcInfo.cpp
index 5dfb5be3c1..1fb2064e09 100644
--- a/widget/android/ProcInfo.cpp
+++ b/widget/android/ProcInfo.cpp
@@ -3,6 +3,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #include "mozilla/ProcInfo.h"
+#include "mozilla/ipc/GeckoChildProcessHost.h"
 
 namespace mozilla {
 
diff --git a/widget/android/components.conf b/widget/android/components.conf
index f12815e2ec..9b617a90be 100644
--- a/widget/android/components.conf
+++ b/widget/android/components.conf
@@ -40,11 +40,14 @@ Classes = [
         'headers': ['/widget/nsTransferable.h'],
     },
     {
+        'js_name': 'clipboard',
         'cid': '{8b5314ba-db01-11d2-96ce-0060b0fb9956}',
         'contract_ids': ['@mozilla.org/widget/clipboard;1'],
+        'interfaces': ['nsIClipboard'],
         'type': 'nsClipboard',
         'headers': ['/widget/android/nsClipboard.h'],
         'processes': ProcessSelector.MAIN_PROCESS_ONLY,
+        'overridable': True,
     },
     {
         'cid': '{77221d5a-1dd2-11b2-8c69-c710f15d2ed5}',
@@ -86,8 +89,10 @@ Classes = [
         'init_method': 'Init',
     },
     {
+        'js_name': 'androidBridge',
         'cid': '{0fe2321d-ebd9-467d-a743-03a68d40599e}',
         'contract_ids': ['@mozilla.org/android/bridge;1'],
+        'interfaces': ['nsIAndroidBridge'],
         'type': 'nsAndroidBridge',
         'headers': ['/widget/android/AndroidBridge.h'],
     },
diff --git a/widget/android/jni/Natives.h b/widget/android/jni/Natives.h
index 0b68672d0a..df64d3065f 100644
--- a/widget/android/jni/Natives.h
+++ b/widget/android/jni/Natives.h
@@ -1,22 +1,26 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
 #ifndef mozilla_jni_Natives_h__
 #define mozilla_jni_Natives_h__
 
 #include <jni.h>
+
+#include <type_traits>
 #include <utility>
 
-#include "nsThreadUtils.h"
-
-#include "mozilla/Move.h"
 #include "mozilla/RefPtr.h"
 #include "mozilla/Tuple.h"
 #include "mozilla/TypeTraits.h"
 #include "mozilla/UniquePtr.h"
-#include "mozilla/WeakPtr.h"
 #include "mozilla/Unused.h"
+#include "mozilla/WeakPtr.h"
 #include "mozilla/jni/Accessors.h"
 #include "mozilla/jni/Refs.h"
 #include "mozilla/jni/Types.h"
 #include "mozilla/jni/Utils.h"
+#include "nsThreadUtils.h"
 
 struct NativeException {
   const char* str;
@@ -122,8 +126,8 @@ enum NativePtrType { OWNING, WEAK, REFPTR };
 template <class Impl>
 class NativePtrPicker {
   template <class I>
-  static typename EnableIf<std::is_base_of<SupportsWeakPtr<I>, I>::value,
-                           char (&)[NativePtrType::WEAK]>::Type
+  static std::enable_if_t<std::is_base_of<SupportsWeakPtr<I>, I>::value,
+                          char (&)[NativePtrType::WEAK]>
   Test(char);
 
   template <class I, typename = decltype(&I::AddRef, &I::Release)>
@@ -356,21 +360,18 @@ class ProxyNativeCall {
   // "this arg" refers to the Class::LocalRef (for static methods) or
   // Owner::LocalRef (for instance methods) that we optionally (as indicated
   // by HasThisArg) pass into the destination C++ function.
-  typedef
-      typename mozilla::Conditional<IsStatic, Class, Owner>::Type ThisArgClass;
-  typedef typename mozilla::Conditional<IsStatic, jclass, jobject>::Type
-      ThisArgJNIType;
+  using ThisArgClass = std::conditional_t<IsStatic, Class, Owner>;
+  using ThisArgJNIType = std::conditional_t<IsStatic, jclass, jobject>;
 
   // Type signature of the destination C++ function, which matches the
   // Method template parameter in NativeStubImpl::Wrap.
-  typedef typename mozilla::Conditional<
+  using NativeCallType = std::conditional_t<
       IsStatic,
-      typename mozilla::Conditional<HasThisArg,
-                                    void (*)(const Class::LocalRef&, Args...),
-                                    void (*)(Args...)>::Type,
-      typename mozilla::Conditional<
+      std::conditional_t<HasThisArg, void (*)(const Class::LocalRef&, Args...),
+                         void (*)(Args...)>,
+      std::conditional_t<
           HasThisArg, void (Impl::*)(const typename Owner::LocalRef&, Args...),
-          void (Impl::*)(Args...)>::Type>::Type NativeCallType;
+          void (Impl::*)(Args...)>>;
 
   // Destination C++ function.
   NativeCallType mNativeCall;
@@ -384,19 +385,19 @@ class ProxyNativeCall {
   // another pair of template parameters, Static and ThisArg.
 
   template <bool Static, bool ThisArg, size_t... Indices>
-  typename mozilla::EnableIf<Static && ThisArg, void>::Type Call(
+  std::enable_if_t<Static && ThisArg, void> Call(
       const Class::LocalRef& cls, std::index_sequence<Indices...>) const {
     (*mNativeCall)(cls, mozilla::Get<Indices>(mArgs)...);
   }
 
   template <bool Static, bool ThisArg, size_t... Indices>
-  typename mozilla::EnableIf<Static && !ThisArg, void>::Type Call(
+  std::enable_if_t<Static && !ThisArg, void> Call(
       const Class::LocalRef& cls, std::index_sequence<Indices...>) const {
     (*mNativeCall)(mozilla::Get<Indices>(mArgs)...);
   }
 
   template <bool Static, bool ThisArg, size_t... Indices>
-  typename mozilla::EnableIf<!Static && ThisArg, void>::Type Call(
+  std::enable_if_t<!Static && ThisArg, void> Call(
       const typename Owner::LocalRef& inst,
       std::index_sequence<Indices...>) const {
     Impl* const impl = NativePtr<Impl>::Get(inst);
@@ -405,7 +406,7 @@ class ProxyNativeCall {
   }
 
   template <bool Static, bool ThisArg, size_t... Indices>
-  typename mozilla::EnableIf<!Static && !ThisArg, void>::Type Call(
+  std::enable_if_t<!Static && !ThisArg, void> Call(
       const typename Owner::LocalRef& inst,
       std::index_sequence<Indices...>) const {
     Impl* const impl = NativePtr<Impl>::Get(inst);
@@ -484,8 +485,7 @@ template <class Impl, bool HasThisArg, typename... Args>
 struct Dispatcher {
   template <class Traits, bool IsStatic = Traits::isStatic,
             typename... ProxyArgs>
-  static typename EnableIf<Traits::dispatchTarget == DispatchTarget::PROXY,
-                           void>::Type
+  static std::enable_if_t<Traits::dispatchTarget == DispatchTarget::PROXY, void>
   Run(ProxyArgs&&... args) {
     Impl::OnNativeCall(
         ProxyNativeCall<Impl, typename Traits::Owner, IsStatic, HasThisArg,
@@ -494,8 +494,8 @@ struct Dispatcher {
 
   template <class Traits, bool IsStatic = Traits::isStatic, typename ThisArg,
             typename... ProxyArgs>
-  static typename EnableIf<
-      Traits::dispatchTarget == DispatchTarget::GECKO_PRIORITY, void>::Type
+  static std::enable_if_t<
+      Traits::dispatchTarget == DispatchTarget::GECKO_PRIORITY, void>
   Run(ThisArg thisArg, ProxyArgs&&... args) {
     // For a static method, do not forward the "this arg" (i.e. the class
     // local ref) if the implementation does not request it. This saves us
@@ -510,8 +510,7 @@ struct Dispatcher {
 
   template <class Traits, bool IsStatic = Traits::isStatic, typename ThisArg,
             typename... ProxyArgs>
-  static typename EnableIf<Traits::dispatchTarget == DispatchTarget::GECKO,
-                           void>::Type
+  static std::enable_if_t<Traits::dispatchTarget == DispatchTarget::GECKO, void>
   Run(ThisArg thisArg, ProxyArgs&&... args) {
     // For a static method, do not forward the "this arg" (i.e. the class
     // local ref) if the implementation does not request it. This saves us
@@ -525,8 +524,8 @@ struct Dispatcher {
   }
 
   template <class Traits, bool IsStatic = false, typename... ProxyArgs>
-  static typename EnableIf<Traits::dispatchTarget == DispatchTarget::CURRENT,
-                           void>::Type
+  static std::enable_if_t<Traits::dispatchTarget == DispatchTarget::CURRENT,
+                          void>
   Run(ProxyArgs&&... args) {
     MOZ_CRASH("Unreachable code");
   }
@@ -565,17 +564,17 @@ class NativeStub<Traits, Impl, jni::Args<Args...>> {
     using JNIType = void;
   };
   using ReturnJNIType =
-      typename Conditional<isVoid, VoidType,
-                           TypeAdapter<ReturnType>>::Type::JNIType;
+      typename std::conditional_t<isVoid, VoidType,
+                                  TypeAdapter<ReturnType>>::JNIType;
 
   using ReturnTypeForNonVoidInstance =
-      typename Conditional<!isStatic && !isVoid, ReturnType, VoidType>::Type;
+      std::conditional_t<!isStatic && !isVoid, ReturnType, VoidType>;
   using ReturnTypeForVoidInstance =
-      typename Conditional<!isStatic && isVoid, ReturnType, VoidType&>::Type;
+      std::conditional_t<!isStatic && isVoid, ReturnType, VoidType&>;
   using ReturnTypeForNonVoidStatic =
-      typename Conditional<isStatic && !isVoid, ReturnType, VoidType>::Type;
+      std::conditional_t<isStatic && !isVoid, ReturnType, VoidType>;
   using ReturnTypeForVoidStatic =
-      typename Conditional<isStatic && isVoid, ReturnType, VoidType&>::Type;
+      std::conditional_t<isStatic && isVoid, ReturnType, VoidType&>;
 
   static_assert(Traits::dispatchTarget == DispatchTarget::CURRENT || isVoid,
                 "Dispatched calls must have void return type");
diff --git a/widget/android/nsAppShell.h b/widget/android/nsAppShell.h
index b306d06ec1..70c209e5ac 100644
--- a/widget/android/nsAppShell.h
+++ b/widget/android/nsAppShell.h
@@ -7,10 +7,12 @@
 
 #include <time.h>
 
+#include <type_traits>
+#include <utility>
+
 #include "mozilla/BackgroundHangMonitor.h"
 #include "mozilla/LinkedList.h"
 #include "mozilla/Monitor.h"
-#include "mozilla/Move.h"
 #include "mozilla/StaticPtr.h"
 #include "mozilla/TimeStamp.h"  // for mozilla::TimeDuration
 #include "mozilla/TypeTraits.h"
@@ -19,9 +21,9 @@
 #include "mozilla/jni/Natives.h"
 #include "nsBaseAppShell.h"
 #include "nsCOMPtr.h"
-#include "nsTArray.h"
-#include "nsInterfaceHashtable.h"
 #include "nsIAndroidBridge.h"
+#include "nsInterfaceHashtable.h"
+#include "nsTArray.h"
 
 namespace mozilla {
 bool ProcessNextEvent();
@@ -130,9 +132,8 @@ class nsAppShell : public nsBaseAppShell {
       const mozilla::TimeDuration timeout = mozilla::TimeDuration::Forever());
 
   template <typename T>
-  static
-      typename mozilla::EnableIf<!std::is_base_of<Event, T>::value, void>::Type
-      SyncRunEvent(T&& lambda) {
+  static std::enable_if_t<!std::is_base_of<Event, T>::value, void> SyncRunEvent(
+      T&& lambda) {
     SyncRunEvent(LambdaEvent<T>(std::forward<T>(lambda)));
   }
 
diff --git a/widget/android/nsWindow.cpp b/widget/android/nsWindow.cpp
index 1a333de3b6..86ec1fa5a3 100644
--- a/widget/android/nsWindow.cpp
+++ b/widget/android/nsWindow.cpp
@@ -7,6 +7,7 @@
 #include <android/native_window_jni.h>
 #include <math.h>
 #include <queue>
+#include <type_traits>
 #include <unistd.h>
 
 #include "mozilla/MiscEvents.h"
@@ -158,17 +159,15 @@ class nsWindow::WindowEvent : public Runnable {
 
 namespace {
 template <class Instance, class Impl>
-typename EnableIf<jni::detail::NativePtrPicker<Impl>::value ==
-                      jni::detail::REFPTR,
-                  void>::Type
+std::enable_if_t<
+    jni::detail::NativePtrPicker<Impl>::value == jni::detail::REFPTR, void>
 CallAttachNative(Instance aInstance, Impl* aImpl) {
   Impl::AttachNative(aInstance, RefPtr<Impl>(aImpl).get());
 }
 
 template <class Instance, class Impl>
-typename EnableIf<jni::detail::NativePtrPicker<Impl>::value ==
-                      jni::detail::OWNING,
-                  void>::Type
+std::enable_if_t<
+    jni::detail::NativePtrPicker<Impl>::value == jni::detail::OWNING, void>
 CallAttachNative(Instance aInstance, Impl* aImpl) {
   Impl::AttachNative(aInstance, UniquePtr<Impl>(aImpl));
 }
diff --git a/widget/cocoa/ProcInfo.mm b/widget/cocoa/ProcInfo.mm
index 7cf467edb1..7f39f997e0 100644
--- a/widget/cocoa/ProcInfo.mm
+++ b/widget/cocoa/ProcInfo.mm
@@ -3,8 +3,8 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #include "mozilla/ProcInfo.h"
-#include "mozilla/Sprintf.h"
-#include "mozilla/Logging.h"
+#include "mozilla/ipc/GeckoChildProcessHost.h"
+
 #include "nsNetCID.h"
 
 #include <cstdio>
@@ -17,7 +17,8 @@
 
 namespace mozilla {
 
-RefPtr<ProcInfoPromise> GetProcInfo(base::ProcessId pid, int32_t childId, const ProcType& type) {
+RefPtr<ProcInfoPromise> GetProcInfo(base::ProcessId pid, int32_t childId, const ProcType& type,
+                                    mach_port_t aChildTask) {
   auto holder = MakeUnique<MozPromiseHolder<ProcInfoPromise>>();
   RefPtr<ProcInfoPromise> promise = holder->Ensure(__func__);
 
@@ -29,7 +30,7 @@ RefPtr<ProcInfoPromise> GetProcInfo(base::ProcessId pid, int32_t childId, const
     return promise;
   }
 
-  auto ResolveGetProcinfo = [holder = std::move(holder), pid, type, childId]() {
+  auto ResolveGetProcinfo = [holder = std::move(holder), pid, type, childId, aChildTask]() {
     ProcInfo info;
     info.pid = pid;
     info.childId = childId;
@@ -56,40 +57,42 @@ RefPtr<ProcInfoPromise> GetProcInfo(base::ProcessId pid, int32_t childId, const
     info.cpuKernel = pti.pti_total_system;
 
     // Now getting threads info
-    mach_port_t task;
-    kern_return_t kret = task_for_pid(mach_task_self(), pid, &task);
-    if (kret != KERN_SUCCESS) {
-      // If we can't get threads detail, we just ignore that.
-      holder->Resolve(info, __func__);
-      return;
+    mach_port_t selectedTask;
+    // If we did not get a task from a child process, we use mach_task_self()
+    if (aChildTask == MACH_PORT_NULL) {
+      selectedTask = mach_task_self();
+    } else {
+      selectedTask = aChildTask;
     }
-
     // task_threads() gives us a snapshot of the process threads
     // but those threads can go away. All the code below makes
     // the assumption that thread_info() calls may fail, and
     // these errors will be ignored.
     thread_act_port_array_t threadList;
     mach_msg_type_number_t threadCount;
-    kret = task_threads(task, &threadList, &threadCount);
+    kern_return_t kret = task_threads(selectedTask, &threadList, &threadCount);
     if (kret != KERN_SUCCESS) {
       holder->Resolve(info, __func__);
       return;
     }
 
+    mach_msg_type_number_t count;
+
     for (mach_msg_type_number_t i = 0; i < threadCount; i++) {
       // Basic thread info.
-      mach_msg_type_number_t threadInfoCount = THREAD_EXTENDED_INFO_COUNT;
       thread_extended_info_data_t threadInfoData;
-      kret = thread_info(threadList[i], THREAD_EXTENDED_INFO, (thread_info_t)&threadInfoData,
-                         &threadInfoCount);
+      count = THREAD_EXTENDED_INFO_COUNT;
+      kret =
+          thread_info(threadList[i], THREAD_EXTENDED_INFO, (thread_info_t)&threadInfoData, &count);
       if (kret != KERN_SUCCESS) {
         continue;
       }
 
       // Getting the thread id.
       thread_identifier_info identifierInfo;
+      count = THREAD_IDENTIFIER_INFO_COUNT;
       kret = thread_info(threadList[i], THREAD_IDENTIFIER_INFO, (thread_info_t)&identifierInfo,
-                         &threadInfoCount);
+                         &count);
       if (kret != KERN_SUCCESS) {
         continue;
       }
@@ -112,5 +115,4 @@ RefPtr<ProcInfoPromise> GetProcInfo(base::ProcessId pid, int32_t childId, const
   }
   return promise;
 }
-
 }
diff --git a/widget/cocoa/ViewRegion.mm b/widget/cocoa/ViewRegion.mm
index 86d98fac29..41b66e5fa3 100644
--- a/widget/cocoa/ViewRegion.mm
+++ b/widget/cocoa/ViewRegion.mm
@@ -27,8 +27,7 @@ bool ViewRegion::UpdateRegion(const LayoutDeviceIntRegion& aRegion,
   // possible, or create new ones or remove old ones if the number of
   // rects in the region has changed.
 
-  nsTArray<NSView*> viewsToRecycle;
-  mViews.SwapElements(viewsToRecycle);
+  nsTArray<NSView*> viewsToRecycle = std::move(mViews);
   // The mViews array is now empty.
 
   size_t i = 0;
diff --git a/widget/cocoa/components.conf b/widget/cocoa/components.conf
new file mode 100644
index 0000000000..c3afd73b9f
--- /dev/null
+++ b/widget/cocoa/components.conf
@@ -0,0 +1,15 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+Classes = [
+    {
+        'js_name': 'clipboard',
+        'cid': '{8b5314ba-db01-11d2-96ce-0060b0fb9956}',
+        'contract_ids': ['@mozilla.org/widget/clipboard;1'],
+        'interfaces': ['nsIClipboard'],
+        'type': 'nsIClipboard',
+        'processes': ProcessSelector.MAIN_PROCESS_ONLY,
+        'overridable': True,
+    },
+]
diff --git a/widget/cocoa/moz.build b/widget/cocoa/moz.build
index c58372696b..700c25c1e2 100644
--- a/widget/cocoa/moz.build
+++ b/widget/cocoa/moz.build
@@ -80,6 +80,10 @@ if not CONFIG['RELEASE_OR_BETA'] or CONFIG['MOZ_DEBUG']:
         'nsSandboxViolationSink.mm',
     ]
 
+XPCOM_MANIFESTS += [
+    'components.conf',
+]
+
 include('/ipc/chromium/chromium-config.mozbuild')
 
 FINAL_LIBRARY = 'xul'
diff --git a/widget/cocoa/nsCocoaUtils.mm b/widget/cocoa/nsCocoaUtils.mm
index fea5faa972..455bd70325 100644
--- a/widget/cocoa/nsCocoaUtils.mm
+++ b/widget/cocoa/nsCocoaUtils.mm
@@ -1234,8 +1234,7 @@ void nsCocoaUtils::ResolveMediaCapturePromises(bool aGranted, PromiseArray& aPro
 
   // Remove each promise from the list and resolve it.
   while (aPromiseList->Length() > 0) {
-    RefPtr<Promise> promise = aPromiseList->LastElement();
-    aPromiseList->RemoveLastElement();
+    RefPtr<Promise> promise = aPromiseList->PopLastElement();
 
     // Resolve on main thread
     nsCOMPtr<nsIRunnable> runnable(NS_NewRunnableFunction(
diff --git a/widget/cocoa/nsWidgetFactory.mm b/widget/cocoa/nsWidgetFactory.mm
index 61b901c71f..bbddac308e 100644
--- a/widget/cocoa/nsWidgetFactory.mm
+++ b/widget/cocoa/nsWidgetFactory.mm
@@ -3,6 +3,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #include "nsISupports.h"
+#include "mozilla/Components.h"
 #include "mozilla/ModuleUtils.h"
 #include "mozilla/WidgetUtils.h"
 
@@ -41,21 +42,15 @@
 using namespace mozilla;
 using namespace mozilla::widget;
 
-static nsresult nsClipboardConstructor(nsISupports* aOuter, REFNSIID aIID, void** aResult) {
+NS_IMPL_COMPONENT_FACTORY(nsIClipboard) {
   nsCOMPtr<nsIClipboard> inst;
-
-  *aResult = nullptr;
-  if (aOuter != nullptr) {
-    return NS_ERROR_NO_AGGREGATION;
-  }
-
   if (gfxPlatform::IsHeadless()) {
     inst = new HeadlessClipboard();
   } else {
     inst = new nsClipboard();
   }
 
-  return inst->QueryInterface(aIID, aResult);
+  return inst.forget();
 }
 
 NS_GENERIC_FACTORY_CONSTRUCTOR(nsFilePicker)
@@ -105,7 +100,6 @@ NS_DEFINE_NAMED_CID(NS_APPSHELL_CID);
 NS_DEFINE_NAMED_CID(NS_SOUND_CID);
 NS_DEFINE_NAMED_CID(NS_TRANSFERABLE_CID);
 NS_DEFINE_NAMED_CID(NS_HTMLFORMATCONVERTER_CID);
-NS_DEFINE_NAMED_CID(NS_CLIPBOARD_CID);
 NS_DEFINE_NAMED_CID(NS_CLIPBOARDHELPER_CID);
 NS_DEFINE_NAMED_CID(NS_DRAGSERVICE_CID);
 NS_DEFINE_NAMED_CID(NS_SCREENMANAGER_CID);
@@ -132,7 +126,6 @@ static const mozilla::Module::CIDEntry kWidgetCIDs[] = {
     {&kNS_SOUND_CID, false, NULL, nsSoundConstructor, mozilla::Module::MAIN_PROCESS_ONLY},
     {&kNS_TRANSFERABLE_CID, false, NULL, nsTransferableConstructor},
     {&kNS_HTMLFORMATCONVERTER_CID, false, NULL, nsHTMLFormatConverterConstructor},
-    {&kNS_CLIPBOARD_CID, false, NULL, nsClipboardConstructor, mozilla::Module::MAIN_PROCESS_ONLY},
     {&kNS_CLIPBOARDHELPER_CID, false, NULL, nsClipboardHelperConstructor},
     {&kNS_DRAGSERVICE_CID, false, NULL, nsDragServiceConstructor,
      mozilla::Module::MAIN_PROCESS_ONLY},
@@ -161,7 +154,6 @@ static const mozilla::Module::ContractIDEntry kWidgetContracts[] = {
     {"@mozilla.org/sound;1", &kNS_SOUND_CID, mozilla::Module::MAIN_PROCESS_ONLY},
     {"@mozilla.org/widget/transferable;1", &kNS_TRANSFERABLE_CID},
     {"@mozilla.org/widget/htmlformatconverter;1", &kNS_HTMLFORMATCONVERTER_CID},
-    {"@mozilla.org/widget/clipboard;1", &kNS_CLIPBOARD_CID, mozilla::Module::MAIN_PROCESS_ONLY},
     {"@mozilla.org/widget/clipboardhelper;1", &kNS_CLIPBOARDHELPER_CID},
     {"@mozilla.org/widget/dragservice;1", &kNS_DRAGSERVICE_CID, mozilla::Module::MAIN_PROCESS_ONLY},
     {"@mozilla.org/gfx/screenmanager;1", &kNS_SCREENMANAGER_CID,
diff --git a/widget/gtk/ProcInfo.cpp b/widget/gtk/ProcInfo.cpp
index 8e424bc27d..bb33afefbd 100644
--- a/widget/gtk/ProcInfo.cpp
+++ b/widget/gtk/ProcInfo.cpp
@@ -5,6 +5,7 @@
 #include "mozilla/ProcInfo.h"
 #include "mozilla/Sprintf.h"
 #include "mozilla/Logging.h"
+#include "mozilla/ipc/GeckoChildProcessHost.h"
 #include "nsAutoRef.h"
 #include "nsLocalFile.h"
 #include "nsNetCID.h"
diff --git a/widget/gtk/components.conf b/widget/gtk/components.conf
index 41656397ef..d1ec058627 100644
--- a/widget/gtk/components.conf
+++ b/widget/gtk/components.conf
@@ -85,10 +85,13 @@ Classes = [
 if defined('MOZ_X11'):
     Classes += [
         {
+            'js_name': 'clipboard',
             'cid': '{8b5314ba-db01-11d2-96ce-0060b0fb9956}',
             'contract_ids': ['@mozilla.org/widget/clipboard;1'],
+            'interfaces': ['nsIClipboard'],
             'type': 'nsIClipboard',
             'processes': ProcessSelector.MAIN_PROCESS_ONLY,
+            'overridable': True,
         },
         {
             'cid': '{77221d5a-1dd2-11b2-8c69-c710f15d2ed5}',
diff --git a/widget/windows/ProcInfo.cpp b/widget/windows/ProcInfo.cpp
index c24c6ee8b8..3f9e8be71c 100644
--- a/widget/windows/ProcInfo.cpp
+++ b/widget/windows/ProcInfo.cpp
@@ -3,6 +3,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #include "mozilla/ProcInfo.h"
+#include "mozilla/ipc/GeckoChildProcessHost.h"
 #include <windows.h>
 #include <psapi.h>
 #include <tlhelp32.h>
diff --git a/widget/windows/ShellHeaderOnlyUtils.h b/widget/windows/ShellHeaderOnlyUtils.h
index 81a301337f..b195ed7f33 100644
--- a/widget/windows/ShellHeaderOnlyUtils.h
+++ b/widget/windows/ShellHeaderOnlyUtils.h
@@ -19,6 +19,7 @@
 // NB: include this after shldisp.h so its macros do not conflict with COM
 // interfaces defined by shldisp.h
 #include <shellapi.h>
+#include <type_traits>
 
 #include <comdef.h>
 #include <comutil.h>
@@ -157,7 +158,7 @@ inline LauncherVoidResult ShellExecuteByExplorer(const _bstr_t& aPath,
 }
 
 using UniqueAbsolutePidl =
-    UniquePtr<RemovePointer<PIDLIST_ABSOLUTE>::Type, CoTaskMemFreeDeleter>;
+    UniquePtr<std::remove_pointer_t<PIDLIST_ABSOLUTE>, CoTaskMemFreeDeleter>;
 
 inline LauncherResult<PIDLIST_ABSOLUTE> ShellParseDisplayName(
     const wchar_t* aPath) {
diff --git a/widget/windows/WinUtils.cpp b/widget/windows/WinUtils.cpp
index 7ee2bfeaf6..558360a8cb 100644
--- a/widget/windows/WinUtils.cpp
+++ b/widget/windows/WinUtils.cpp
@@ -415,25 +415,34 @@ const char FaviconHelper::kJumpListCacheDir[] = "jumpListCache";
 const char FaviconHelper::kShortcutCacheDir[] = "shortcutCache";
 
 // apis available on vista and up.
-WinUtils::SHCreateItemFromParsingNamePtr WinUtils::sCreateItemFromParsingName = nullptr;
+WinUtils::SHCreateItemFromParsingNamePtr WinUtils::sCreateItemFromParsingName =
+    nullptr;
 WinUtils::SHGetKnownFolderPathPtr WinUtils::sGetKnownFolderPath = nullptr;
 
 // We just leak these DLL HMODULEs. There's no point in calling FreeLibrary
 // on them during shutdown anyway.
-static const wchar_t kShellLibraryName[] =  L"shell32.dll";
+static const wchar_t kShellLibraryName[] = L"shell32.dll";
 static HMODULE sShellDll = nullptr;
 static const wchar_t kDwmLibraryName[] = L"dwmapi.dll";
 static HMODULE sDwmDll = nullptr;
 
-WinUtils::DwmExtendFrameIntoClientAreaProc WinUtils::dwmExtendFrameIntoClientAreaPtr = nullptr;
-WinUtils::DwmIsCompositionEnabledProc WinUtils::dwmIsCompositionEnabledPtr = nullptr;
-WinUtils::DwmSetIconicThumbnailProc WinUtils::dwmSetIconicThumbnailPtr = nullptr;
-WinUtils::DwmSetIconicLivePreviewBitmapProc WinUtils::dwmSetIconicLivePreviewBitmapPtr = nullptr;
-WinUtils::DwmGetWindowAttributeProc WinUtils::dwmGetWindowAttributePtr = nullptr;
-WinUtils::DwmSetWindowAttributeProc WinUtils::dwmSetWindowAttributePtr = nullptr;
-WinUtils::DwmInvalidateIconicBitmapsProc WinUtils::dwmInvalidateIconicBitmapsPtr = nullptr;
+WinUtils::DwmExtendFrameIntoClientAreaProc
+    WinUtils::dwmExtendFrameIntoClientAreaPtr = nullptr;
+WinUtils::DwmIsCompositionEnabledProc WinUtils::dwmIsCompositionEnabledPtr =
+    nullptr;
+WinUtils::DwmSetIconicThumbnailProc WinUtils::dwmSetIconicThumbnailPtr =
+    nullptr;
+WinUtils::DwmSetIconicLivePreviewBitmapProc
+    WinUtils::dwmSetIconicLivePreviewBitmapPtr = nullptr;
+WinUtils::DwmGetWindowAttributeProc WinUtils::dwmGetWindowAttributePtr =
+    nullptr;
+WinUtils::DwmSetWindowAttributeProc WinUtils::dwmSetWindowAttributePtr =
+    nullptr;
+WinUtils::DwmInvalidateIconicBitmapsProc
+    WinUtils::dwmInvalidateIconicBitmapsPtr = nullptr;
 WinUtils::DwmDefWindowProcProc WinUtils::dwmDwmDefWindowProcPtr = nullptr;
-WinUtils::DwmGetCompositionTimingInfoProc WinUtils::dwmGetCompositionTimingInfoPtr = nullptr;
+WinUtils::DwmGetCompositionTimingInfoProc
+    WinUtils::dwmGetCompositionTimingInfoPtr = nullptr;
 WinUtils::DwmFlushProc WinUtils::dwmFlushProcPtr = nullptr;
 
 // Prefix for path used by NT calls.
@@ -454,15 +463,29 @@ void WinUtils::Initialize() {
     sDwmDll = ::LoadLibraryW(kDwmLibraryName);
 
     if (sDwmDll) {
-      dwmExtendFrameIntoClientAreaPtr = (DwmExtendFrameIntoClientAreaProc)::GetProcAddress(sDwmDll, "DwmExtendFrameIntoClientArea");
-      dwmIsCompositionEnabledPtr = (DwmIsCompositionEnabledProc)::GetProcAddress(sDwmDll, "DwmIsCompositionEnabled");
-      dwmSetIconicThumbnailPtr = (DwmSetIconicThumbnailProc)::GetProcAddress(sDwmDll, "DwmSetIconicThumbnail");
-      dwmSetIconicLivePreviewBitmapPtr = (DwmSetIconicLivePreviewBitmapProc)::GetProcAddress(sDwmDll, "DwmSetIconicLivePreviewBitmap");
-      dwmGetWindowAttributePtr = (DwmGetWindowAttributeProc)::GetProcAddress(sDwmDll, "DwmGetWindowAttribute");
-      dwmSetWindowAttributePtr = (DwmSetWindowAttributeProc)::GetProcAddress(sDwmDll, "DwmSetWindowAttribute");
-      dwmInvalidateIconicBitmapsPtr = (DwmInvalidateIconicBitmapsProc)::GetProcAddress(sDwmDll, "DwmInvalidateIconicBitmaps");
-      dwmDwmDefWindowProcPtr = (DwmDefWindowProcProc)::GetProcAddress(sDwmDll, "DwmDefWindowProc");
-      dwmGetCompositionTimingInfoPtr = (DwmGetCompositionTimingInfoProc)::GetProcAddress(sDwmDll, "DwmGetCompositionTimingInfo");
+      dwmExtendFrameIntoClientAreaPtr =
+          (DwmExtendFrameIntoClientAreaProc)::GetProcAddress(
+              sDwmDll, "DwmExtendFrameIntoClientArea");
+      dwmIsCompositionEnabledPtr =
+          (DwmIsCompositionEnabledProc)::GetProcAddress(
+              sDwmDll, "DwmIsCompositionEnabled");
+      dwmSetIconicThumbnailPtr = (DwmSetIconicThumbnailProc)::GetProcAddress(
+          sDwmDll, "DwmSetIconicThumbnail");
+      dwmSetIconicLivePreviewBitmapPtr =
+          (DwmSetIconicLivePreviewBitmapProc)::GetProcAddress(
+              sDwmDll, "DwmSetIconicLivePreviewBitmap");
+      dwmGetWindowAttributePtr = (DwmGetWindowAttributeProc)::GetProcAddress(
+          sDwmDll, "DwmGetWindowAttribute");
+      dwmSetWindowAttributePtr = (DwmSetWindowAttributeProc)::GetProcAddress(
+          sDwmDll, "DwmSetWindowAttribute");
+      dwmInvalidateIconicBitmapsPtr =
+          (DwmInvalidateIconicBitmapsProc)::GetProcAddress(
+              sDwmDll, "DwmInvalidateIconicBitmaps");
+      dwmDwmDefWindowProcPtr =
+          (DwmDefWindowProcProc)::GetProcAddress(sDwmDll, "DwmDefWindowProc");
+      dwmGetCompositionTimingInfoPtr =
+          (DwmGetCompositionTimingInfoProc)::GetProcAddress(
+              sDwmDll, "DwmGetCompositionTimingInfo");
       dwmFlushProcPtr = (DwmFlushProc)::GetProcAddress(sDwmDll, "DwmFlush");
     }
   }
@@ -622,7 +645,8 @@ GETPROCESSDPIAWARENESSPROC sGetProcessDpiAwareness;
 static bool SlowIsPerMonitorDPIAware() {
   if (IsVistaOrLater()) {
     // Intentionally leak the handle.
-    HMODULE shcore = LoadLibraryEx(L"shcore", NULL, LOAD_LIBRARY_SEARCH_SYSTEM32);
+    HMODULE shcore =
+        LoadLibraryEx(L"shcore", NULL, LOAD_LIBRARY_SEARCH_SYSTEM32);
     if (shcore) {
       sGetDpiForMonitor =
           (GETDPIFORMONITORPROC)GetProcAddress(shcore, "GetDpiForMonitor");
@@ -1094,8 +1118,8 @@ MSG WinUtils::InitMSG(UINT aMessage, WPARAM wParam, LPARAM lParam, HWND aWnd) {
 }
 
 /* static */
-HRESULT WinUtils::SHCreateItemFromParsingName(PCWSTR pszPath, IBindCtx *pbc,
-                                      REFIID riid, void **ppv) {
+HRESULT WinUtils::SHCreateItemFromParsingName(PCWSTR pszPath, IBindCtx* pbc,
+                                              REFIID riid, void** ppv) {
   if (sCreateItemFromParsingName) {
     return sCreateItemFromParsingName(pszPath, pbc, riid, ppv);
   }
@@ -1107,19 +1131,16 @@ HRESULT WinUtils::SHCreateItemFromParsingName(PCWSTR pszPath, IBindCtx *pbc,
     }
   }
 
-  sCreateItemFromParsingName = (SHCreateItemFromParsingNamePtr)
-    GetProcAddress(sShellDll, "SHCreateItemFromParsingName");
-  if (!sCreateItemFromParsingName)
-    return E_FAIL;
+  sCreateItemFromParsingName = (SHCreateItemFromParsingNamePtr)GetProcAddress(
+      sShellDll, "SHCreateItemFromParsingName");
+  if (!sCreateItemFromParsingName) return E_FAIL;
 
   return sCreateItemFromParsingName(pszPath, pbc, riid, ppv);
 }
 
 /* static */
-HRESULT WinUtils::SHGetKnownFolderPath(REFKNOWNFOLDERID rfid,
-                               DWORD dwFlags,
-                               HANDLE hToken,
-                               PWSTR *ppszPath) {
+HRESULT WinUtils::SHGetKnownFolderPath(REFKNOWNFOLDERID rfid, DWORD dwFlags,
+                                       HANDLE hToken, PWSTR* ppszPath) {
   if (sGetKnownFolderPath) {
     return sGetKnownFolderPath(rfid, dwFlags, hToken, ppszPath);
   }
@@ -1131,10 +1152,9 @@ HRESULT WinUtils::SHGetKnownFolderPath(REFKNOWNFOLDERID rfid,
     }
   }
 
-  sGetKnownFolderPath = (SHGetKnownFolderPathPtr)
-    GetProcAddress(sShellDll, "SHGetKnownFolderPath");
-  if (!sGetKnownFolderPath)
-    return E_FAIL;
+  sGetKnownFolderPath = (SHGetKnownFolderPathPtr)GetProcAddress(
+      sShellDll, "SHGetKnownFolderPath");
+  if (!sGetKnownFolderPath) return E_FAIL;
 
   return sGetKnownFolderPath(rfid, dwFlags, hToken, ppszPath);
 }
@@ -1974,10 +1994,10 @@ PointerCapabilities WinUtils::GetAllPointerCapabilities() {
   return result;
 }
 
-typedef DWORD (WINAPI * GetFinalPathNameByHandlePtr)(HANDLE hFile,
-                                                    LPTSTR lpszFilePath,
-                                                    DWORD cchFilePath,
-                                                    DWORD dwFlags);
+typedef DWORD(WINAPI* GetFinalPathNameByHandlePtr)(HANDLE hFile,
+                                                   LPTSTR lpszFilePath,
+                                                   DWORD cchFilePath,
+                                                   DWORD dwFlags);
 /* static */
 bool WinUtils::ResolveJunctionPointsAndSymLinks(std::wstring& aPath) {
   LOG_D("ResolveJunctionPointsAndSymLinks: Resolving path: %S", aPath.c_str());
@@ -1999,16 +2019,16 @@ bool WinUtils::ResolveJunctionPointsAndSymLinks(std::wstring& aPath) {
   GetFinalPathNameByHandlePtr getFinalPathNameFnPtr = nullptr;
   HMODULE kernel32Dll = ::GetModuleHandleW(L"Kernel32");
   if (kernel32Dll) {
-    getFinalPathNameFnPtr = (GetFinalPathNameByHandlePtr)
-      ::GetProcAddress(kernel32Dll, "GetFinalPathNameByHandleW");
+    getFinalPathNameFnPtr = (GetFinalPathNameByHandlePtr)::GetProcAddress(
+        kernel32Dll, "GetFinalPathNameByHandleW");
   }
 
   if (!getFinalPathNameFnPtr) {
     return false;
   }
 
-  DWORD pathLen = getFinalPathNameFnPtr(
-    handle, path, MAX_PATH, FILE_NAME_NORMALIZED | VOLUME_NAME_DOS);
+  DWORD pathLen = getFinalPathNameFnPtr(handle, path, MAX_PATH,
+                                        FILE_NAME_NORMALIZED | VOLUME_NAME_DOS);
   if (pathLen == 0 || pathLen >= MAX_PATH) {
     return false;
   }
@@ -2148,23 +2168,23 @@ bool WinUtils::UnexpandEnvVars(nsAString& aPath) {
  * @see PreparePathForTelemetry for an example of its usage.
  */
 /* static */
-const nsTArray<mozilla::Pair<nsString, nsDependentString>>&
+const nsTArray<std::pair<nsString, nsDependentString>>&
 WinUtils::GetWhitelistedPaths() {
   // We know the maximum number of items this array will hold, so avoid a heap
   // allocation by using AutoTArray<T,N>
   static const size_t kMaxWhitelistedItems = 2;
   static StaticAutoPtr<
-      AutoTArray<Pair<nsString, nsDependentString>, kMaxWhitelistedItems>>
+      AutoTArray<std::pair<nsString, nsDependentString>, kMaxWhitelistedItems>>
       sWhitelist;
   if (sWhitelist) {
     return *sWhitelist;
   }
-  sWhitelist =
-      new AutoTArray<Pair<nsString, nsDependentString>, kMaxWhitelistedItems>();
-  sWhitelist->AppendElement(mozilla::MakePair(
+  sWhitelist = new AutoTArray<std::pair<nsString, nsDependentString>,
+                              kMaxWhitelistedItems>();
+  sWhitelist->AppendElement(std::make_pair(
       nsString(NS_LITERAL_STRING("%ProgramFiles%")), nsDependentString()));
   // When no substitution is required, set the void flag
-  sWhitelist->LastElement().second().SetIsVoid(true);
+  sWhitelist->LastElement().second.SetIsVoid(true);
   wchar_t tmpPath[MAX_PATH + 1] = {0};
   if (GetTempPath(MAX_PATH, tmpPath)) {
     // GetTempPath's result always ends with a backslash, which we don't want
@@ -2174,8 +2194,8 @@ WinUtils::GetWhitelistedPaths() {
     }
     nsAutoString cleanTmpPath(tmpPath);
     if (UnexpandEnvVars(cleanTmpPath)) {
-      sWhitelist->AppendElement(mozilla::MakePair(
-          nsString(cleanTmpPath), nsDependentString(L"%TEMP%")));
+      sWhitelist->AppendElement(
+          std::make_pair(nsString(cleanTmpPath), nsDependentString(L"%TEMP%")));
     }
   }
   ClearOnShutdown(&sWhitelist);
@@ -2273,12 +2293,12 @@ bool WinUtils::PreparePathForTelemetry(nsAString& aPath,
     }
   }
 
-  const nsTArray<Pair<nsString, nsDependentString>>& whitelistedPaths =
+  const nsTArray<std::pair<nsString, nsDependentString>>& whitelistedPaths =
       GetWhitelistedPaths();
 
   for (uint32_t i = 0; i < whitelistedPaths.Length(); ++i) {
-    const nsString& testPath = whitelistedPaths[i].first();
-    const nsDependentString& substitution = whitelistedPaths[i].second();
+    const nsString& testPath = whitelistedPaths[i].first;
+    const nsDependentString& substitution = whitelistedPaths[i].second;
     if (StringBeginsWith(aPath, testPath,
                          nsCaseInsensitiveStringComparator())) {
       if (!substitution.IsVoid()) {
diff --git a/widget/windows/WinUtils.h b/widget/windows/WinUtils.h
index d47290d0ac..43c64266e2 100644
--- a/widget/windows/WinUtils.h
+++ b/widget/windows/WinUtils.h
@@ -615,7 +615,7 @@ class WinUtils {
                                                      PWSTR *ppszPath);
   static SHGetKnownFolderPathPtr sGetKnownFolderPath;
 
-  static const nsTArray<Pair<nsString, nsDependentString>>&
+  static const nsTArray<std::pair<nsString, nsDependentString>>&
   GetWhitelistedPaths();
 
 #ifdef ACCESSIBILITY
diff --git a/widget/windows/components.conf b/widget/windows/components.conf
index 10e3cf7641..773d2b752f 100644
--- a/widget/windows/components.conf
+++ b/widget/windows/components.conf
@@ -139,10 +139,13 @@ Classes = [
         'processes': ProcessSelector.MAIN_PROCESS_ONLY,
     },
     {
+        'js_name': 'clipboard',
         'cid': '{8b5314ba-db01-11d2-96ce-0060b0fb9956}',
         'contract_ids': ['@mozilla.org/widget/clipboard;1'],
+        'interfaces': ['nsIClipboard'],
         'type': 'nsIClipboard',
         'processes': ProcessSelector.MAIN_PROCESS_ONLY,
+        'overridable': True,
     },
 ]
 
diff --git a/widget/windows/nsPrintSettingsServiceWin.cpp b/widget/windows/nsPrintSettingsServiceWin.cpp
index 56d1c30e1e..601f7c7043 100644
--- a/widget/windows/nsPrintSettingsServiceWin.cpp
+++ b/widget/windows/nsPrintSettingsServiceWin.cpp
@@ -68,7 +68,7 @@ nsPrintSettingsServiceWin::SerializeToPrintData(nsIPrintSettings* aSettings,
       const char* devModeData = reinterpret_cast<const char*>(devMode.get());
       nsTArray<uint8_t> arrayBuf;
       arrayBuf.AppendElements(devModeData, devModeTotalSize);
-      data->devModeData().SwapElements(arrayBuf);
+      data->devModeData() = std::move(arrayBuf);
     }
   }
 
diff --git a/xpcom/base/AutoRestore.h b/xpcom/base/AutoRestore.h
index 3bdc5dd699..bf8da21d82 100644
--- a/xpcom/base/AutoRestore.h
+++ b/xpcom/base/AutoRestore.h
@@ -8,7 +8,6 @@
 #define mozilla_AutoRestore_h_
 
 #include "mozilla/Attributes.h"  // MOZ_STACK_CLASS
-#include "mozilla/GuardObjects.h"
 
 namespace mozilla {
 
@@ -29,12 +28,8 @@ class MOZ_RAII AutoRestore {
  private:
   T& mLocation;
   T mValue;
-  MOZ_DECL_USE_GUARD_OBJECT_NOTIFIER
  public:
-  explicit AutoRestore(T& aValue MOZ_GUARD_OBJECT_NOTIFIER_PARAM)
-      : mLocation(aValue), mValue(aValue) {
-    MOZ_GUARD_OBJECT_NOTIFIER_INIT;
-  }
+  explicit AutoRestore(T& aValue) : mLocation(aValue), mValue(aValue) {}
   ~AutoRestore() { mLocation = mValue; }
   T SavedValue() const { return mValue; }
 };
diff --git a/xpcom/base/CodeAddressService.h b/xpcom/base/CodeAddressService.h
index cae9c752eb..02c08d46cb 100644
--- a/xpcom/base/CodeAddressService.h
+++ b/xpcom/base/CodeAddressService.h
@@ -5,30 +5,56 @@
 #ifndef CodeAddressService_h__
 #define CodeAddressService_h__
 
+#include "mozilla/AllocPolicy.h"
 #include "mozilla/Assertions.h"
 #include "mozilla/HashFunctions.h"
+#include "mozilla/HashTable.h"
 #include "mozilla/IntegerPrintfMacros.h"
 #include "mozilla/MemoryReporting.h"
-#include "mozilla/Types.h"
-
 #include "mozilla/StackWalk.h"
+#include "mozilla/Types.h"
 
 namespace mozilla {
 
+namespace detail {
+
+template <class AllocPolicy>
+class CodeAddressServiceAllocPolicy : public AllocPolicy {
+ public:
+  char* strdup_(const char* aStr) {
+    char* s = AllocPolicy::template pod_malloc<char>(strlen(aStr) + 1);
+    if (!s) {
+      MOZ_CRASH("CodeAddressService OOM");
+    }
+    strcpy(s, aStr);
+    return s;
+  }
+};
+
+// Default implementation of DescribeCodeAddressLock.
+struct DefaultDescribeCodeAddressLock {
+  static void Unlock() {}
+  static void Lock() {}
+  // Because CodeAddressService asserts that IsLocked() is true, returning true
+  // here is a sensible default when there is no relevant lock.
+  static bool IsLocked() { return true; }
+};
+
+}  // namespace detail
+
 // This class is used to print details about code locations.
 //
-// |StringTable| must implement an Intern() method that returns an interned
-// copy of the string that was passed in, as well as a standard
-// SizeOfExcludingThis() method.
-//
-// |StringAlloc| must implement |copy| and |free|. |copy| copies a string,
-// while |free| is used to free strings created by |copy|.
+// |AllocPolicy_| must adhere to the description in mfbt/AllocPolicy.h.
 //
 // |DescribeCodeAddressLock| is needed when the callers may be holding a lock
 // used by MozDescribeCodeAddress.  |DescribeCodeAddressLock| must implement
 // static methods IsLocked(), Unlock() and Lock().
-template <class StringTable, class StringAlloc, class DescribeCodeAddressLock>
-class CodeAddressService {
+template <class AllocPolicy_ = MallocAllocPolicy,
+          class DescribeCodeAddressLock =
+              detail::DefaultDescribeCodeAddressLock>
+class CodeAddressService
+    : private detail::CodeAddressServiceAllocPolicy<AllocPolicy_> {
+ protected:
   // GetLocation() is the key function in this class.  It's basically a wrapper
   // around MozDescribeCodeAddress.
   //
@@ -47,9 +73,12 @@ class CodeAddressService {
   //   overwritten, and their copies released.  In addition, empty function
   //   names are common, so we use nullptr to represent them compactly.
 
-  StringTable mLibraryStrings;
+  using AllocPolicy = detail::CodeAddressServiceAllocPolicy<AllocPolicy_>;
+  using StringHashSet = HashSet<const char*, CStringHasher, AllocPolicy>;
 
-  struct Entry {
+  StringHashSet mLibraryStrings;
+
+  struct Entry : private AllocPolicy {
     const void* mPc;
     char* mFunction;       // owned by the Entry;  may be null
     const char* mLibrary;  // owned by mLibraryStrings;  never null
@@ -70,8 +99,8 @@ class CodeAddressService {
 
     ~Entry() {
       // We don't free mLibrary because it's externally owned.
-      StringAlloc::free(mFunction);
-      StringAlloc::free(mFileName);
+      AllocPolicy::free_(mFunction);
+      AllocPolicy::free_(mFileName);
     }
 
     void Replace(const void* aPc, const char* aFunction, const char* aLibrary,
@@ -80,10 +109,10 @@ class CodeAddressService {
       mPc = aPc;
 
       // Convert "" to nullptr.  Otherwise, make a copy of the name.
-      StringAlloc::free(mFunction);
-      mFunction = !aFunction[0] ? nullptr : StringAlloc::copy(aFunction);
-      StringAlloc::free(mFileName);
-      mFileName = !aFileName[0] ? nullptr : StringAlloc::copy(aFileName);
+      AllocPolicy::free_(mFunction);
+      mFunction = !aFunction[0] ? nullptr : AllocPolicy::strdup_(aFunction);
+      AllocPolicy::free_(mFileName);
+      mFileName = !aFileName[0] ? nullptr : AllocPolicy::strdup_(aFileName);
 
       mLibrary = aLibrary;
       mLOffset = aLOffset;
@@ -101,24 +130,20 @@ class CodeAddressService {
     }
   };
 
-  // A direct-mapped cache.  When doing dmd::Analyze() just after starting
-  // desktop Firefox (which is similar to analyzing after a longer-running
-  // session, thanks to the limit on how many records we print), a cache with
-  // 2^24 entries (which approximates an infinite-entry cache) has a ~91% hit
-  // rate.  A cache with 2^12 entries has a ~83% hit rate, and takes up ~85 KiB
-  // (on 32-bit platforms) or ~150 KiB (on 64-bit platforms).
-  static const size_t kNumEntries = 1 << 12;
-  static const size_t kMask = kNumEntries - 1;
-  Entry mEntries[kNumEntries];
+  const char* InternLibraryString(const char* aString) {
+    auto p = mLibraryStrings.lookupForAdd(aString);
+    if (p) {
+      return *p;
+    }
 
-  size_t mNumCacheHits;
-  size_t mNumCacheMisses;
+    const char* newString = AllocPolicy::strdup_(aString);
+    if (!mLibraryStrings.add(p, newString)) {
+      MOZ_CRASH("CodeAddressService OOM");
+    }
+    return newString;
+  }
 
- public:
-  CodeAddressService() : mEntries(), mNumCacheHits(0), mNumCacheMisses(0) {}
-
-  void GetLocation(uint32_t aFrameNumber, const void* aPc, char* aBuf,
-                   size_t aBufLen) {
+  Entry& GetEntry(const void* aPc) {
     MOZ_ASSERT(DescribeCodeAddressLock::IsLocked());
 
     uint32_t index = HashGeneric(aPc) & kMask;
@@ -140,7 +165,7 @@ class CodeAddressService {
         DescribeCodeAddressLock::Lock();
       }
 
-      const char* library = mLibraryStrings.Intern(details.library);
+      const char* library = InternLibraryString(details.library);
       entry.Replace(aPc, details.function, library, details.loffset,
                     details.filename, details.lineno);
 
@@ -150,6 +175,35 @@ class CodeAddressService {
 
     MOZ_ASSERT(entry.mPc == aPc);
 
+    return entry;
+  }
+
+  // A direct-mapped cache.  When doing dmd::Analyze() just after starting
+  // desktop Firefox (which is similar to analyzing after a longer-running
+  // session, thanks to the limit on how many records we print), a cache with
+  // 2^24 entries (which approximates an infinite-entry cache) has a ~91% hit
+  // rate.  A cache with 2^12 entries has a ~83% hit rate, and takes up ~85 KiB
+  // (on 32-bit platforms) or ~150 KiB (on 64-bit platforms).
+  static const size_t kNumEntries = 1 << 12;
+  static const size_t kMask = kNumEntries - 1;
+  Entry mEntries[kNumEntries];
+
+  size_t mNumCacheHits;
+  size_t mNumCacheMisses;
+
+ public:
+  CodeAddressService()
+      : mLibraryStrings(64), mEntries(), mNumCacheHits(0), mNumCacheMisses(0) {}
+
+  ~CodeAddressService() {
+    for (auto iter = mLibraryStrings.iter(); !iter.done(); iter.next()) {
+      AllocPolicy::free_(const_cast<char*>(iter.get()));
+    }
+  }
+
+  void GetLocation(uint32_t aFrameNumber, const void* aPc, char* aBuf,
+                   size_t aBufLen) {
+    Entry& entry = GetEntry(aPc);
     MozFormatCodeAddress(aBuf, aBufLen, aFrameNumber, entry.mPc,
                          entry.mFunction, entry.mLibrary, entry.mLOffset,
                          entry.mFileName, entry.mLineNo);
@@ -161,7 +215,10 @@ class CodeAddressService {
       n += mEntries[i].SizeOfExcludingThis(aMallocSizeOf);
     }
 
-    n += mLibraryStrings.SizeOfExcludingThis(aMallocSizeOf);
+    n += mLibraryStrings.shallowSizeOfExcludingThis(aMallocSizeOf);
+    for (auto iter = mLibraryStrings.iter(); !iter.done(); iter.next()) {
+      n += aMallocSizeOf(iter.get());
+    }
 
     return n;
   }
diff --git a/xpcom/base/CycleCollectedJSContext.cpp b/xpcom/base/CycleCollectedJSContext.cpp
index 5f3068f1ab..1ed8a78766 100644
--- a/xpcom/base/CycleCollectedJSContext.cpp
+++ b/xpcom/base/CycleCollectedJSContext.cpp
@@ -3,12 +3,19 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #include "mozilla/CycleCollectedJSContext.h"
+
 #include <algorithm>
+#include <utility>
+
+#include "js/Debug.h"
+#include "js/GCAPI.h"
+#include "js/Utility.h"
+#include "jsapi.h"
 #include "mozilla/ArrayUtils.h"
 #include "mozilla/AsyncEventDispatcher.h"
 #include "mozilla/AutoRestore.h"
 #include "mozilla/CycleCollectedJSRuntime.h"
-#include "mozilla/Move.h"
+#include "mozilla/DebuggerOnGCRunnable.h"
 #include "mozilla/MemoryReporting.h"
 #include "mozilla/Sprintf.h"
 #include "mozilla/SystemGroup.h"
@@ -16,9 +23,9 @@
 #include "mozilla/TimelineConsumers.h"
 #include "mozilla/TimelineMarker.h"
 #include "mozilla/Unused.h"
-#include "mozilla/DebuggerOnGCRunnable.h"
-#include "mozilla/dom/DOMJSClass.h"
 #include "mozilla/dom/DOMException.h"
+#include "mozilla/dom/DOMJSClass.h"
+#include "mozilla/dom/FinalizationRegistryBinding.h"
 #include "mozilla/dom/ProfileTimelineMarkerBinding.h"
 #include "mozilla/dom/PromiseBinding.h"
 #include "mozilla/dom/PromiseDebugging.h"
@@ -26,10 +33,6 @@
 #include "mozilla/dom/PromiseRejectionEventBinding.h"
 #include "mozilla/dom/ScriptSettings.h"
 #include "mozilla/dom/UserActivation.h"
-#include "jsapi.h"
-#include "js/Debug.h"
-#include "js/GCAPI.h"
-#include "js/Utility.h"
 #include "nsContentUtils.h"
 #include "nsCycleCollectionNoteRootCallback.h"
 #include "nsCycleCollectionParticipant.h"
@@ -38,11 +41,10 @@
 #include "nsDOMMutationObserver.h"
 #include "nsJSUtils.h"
 #include "nsPIDOMWindow.h"
-#include "nsWrapperCache.h"
 #include "nsStringBuffer.h"
-
 #include "nsThread.h"
 #include "nsThreadUtils.h"
+#include "nsWrapperCache.h"
 #include "xpcpublic.h"
 
 using namespace mozilla;
@@ -57,13 +59,10 @@ CycleCollectedJSContext::CycleCollectedJSContext()
       mTargetedMicroTaskRecursionDepth(0),
       mMicroTaskLevel(0),
       mDebuggerRecursionDepth(0),
-      mMicroTaskRecursionDepth(0) {
+      mMicroTaskRecursionDepth(0),
+      mFinalizationRegistryCleanup(this) {
   MOZ_COUNT_CTOR(CycleCollectedJSContext);
 
-  // Reinitialize PerThreadAtomCache because dom/bindings/Codegen.py compares
-  // against zero rather than JSID_VOID to detect uninitialized jsid members.
-  memset(static_cast<PerThreadAtomCache*>(this), 0, sizeof(PerThreadAtomCache));
-
   nsCOMPtr<nsIThread> thread = do_GetCurrentThread();
   mOwningThread = thread.forget().downcast<nsThread>().take();
   MOZ_RELEASE_ASSERT(mOwningThread);
@@ -77,7 +76,6 @@ CycleCollectedJSContext::~CycleCollectedJSContext() {
   }
 
   JS::SetHostCleanupFinalizationRegistryCallback(mJSContext, nullptr, nullptr);
-  mFinalizationRegistriesToCleanUp.reset();
 
   JS_SetContextPrivate(mJSContext, nullptr);
 
@@ -103,6 +101,8 @@ CycleCollectedJSContext::~CycleCollectedJSContext() {
   mAboutToBeNotifiedRejectedPromises.Clear();
   mPendingUnhandledRejections.Clear();
 
+  mFinalizationRegistryCleanup.Destroy();
+
   JS_DestroyContext(mJSContext);
   mJSContext = nullptr;
 
@@ -146,9 +146,7 @@ nsresult CycleCollectedJSContext::Initialize(JSRuntime* aParentRuntime,
                            JS::GCVector<JSObject*, 0, js::SystemAllocPolicy>(
                                js::SystemAllocPolicy()));
 
-  mFinalizationRegistriesToCleanUp.init(mJSContext);
-  JS::SetHostCleanupFinalizationRegistryCallback(
-      mJSContext, CleanupFinalizationRegistryCallback, this);
+  mFinalizationRegistryCleanup.Init();
 
   // Cast to PerThreadAtomCache for dom::GetAtomCache(JSContext*).
   JS_SetContextPrivate(mJSContext, static_cast<PerThreadAtomCache*>(this));
@@ -738,56 +736,96 @@ nsresult CycleCollectedJSContext::NotifyUnhandledRejections::Cancel() {
   return NS_OK;
 }
 
-class CleanupFinalizationRegistriesRunnable : public CancelableRunnable {
+class FinalizationRegistryCleanup::CleanupRunnable : public CancelableRunnable {
  public:
-  explicit CleanupFinalizationRegistriesRunnable(
-      CycleCollectedJSContext* aContext)
-      : CancelableRunnable("CleanupFinalizationRegistriesRunnable"),
-        mContext(aContext) {}
-  NS_DECL_NSIRUNNABLE
- private:
-  CycleCollectedJSContext* mContext;
-};
+  explicit CleanupRunnable(FinalizationRegistryCleanup* aCleanupWork)
+      : CancelableRunnable("CleanupRunnable"), mCleanupWork(aCleanupWork) {}
 
-NS_IMETHODIMP
-CleanupFinalizationRegistriesRunnable::Run() {
-  if (mContext->mFinalizationRegistriesToCleanUp.empty()) {
+  // MOZ_CAN_RUN_SCRIPT_BOUNDARY until Runnable::Run is MOZ_CAN_RUN_SCRIPT.  See
+  // bug 1535398.
+  MOZ_CAN_RUN_SCRIPT_BOUNDARY
+  NS_IMETHODIMP Run() {
+    mCleanupWork->DoCleanup();
     return NS_OK;
   }
 
-  JS::RootingContext* cx = mContext->RootingCx();
+ private:
+  FinalizationRegistryCleanup* mCleanupWork;
+};
 
-  JS::Rooted<CycleCollectedJSContext::ObjectVector> registries(cx);
-  std::swap(registries.get(), mContext->mFinalizationRegistriesToCleanUp.get());
+FinalizationRegistryCleanup::FinalizationRegistryCleanup(
+    CycleCollectedJSContext* aContext)
+    : mContext(aContext) {}
 
-  JS::Rooted<JSObject*> registry(cx);
-  for (const auto& r : registries) {
-    registry = r;
+void FinalizationRegistryCleanup::Destroy() {
+  // This must happen before the CycleCollectedJSContext destructor calls
+  // JS_DestroyContext().
+  mCallbacks.reset();
+}
 
-    AutoEntryScript aes(registry, "cleanupFinalizationRegistry");
-    mozilla::Unused << JS::CleanupQueuedFinalizationRegistry(aes.cx(),
-                                                             registry);
-  }
-
-  return NS_OK;
+void FinalizationRegistryCleanup::Init() {
+  JSContext* cx = mContext->Context();
+  mCallbacks.init(cx);
+  JS::SetHostCleanupFinalizationRegistryCallback(cx, QueueCallback, this);
 }
 
 /* static */
-void CycleCollectedJSContext::CleanupFinalizationRegistryCallback(
-    JSObject* aRegistry, void* aData) {
-  CycleCollectedJSContext* ccjs = static_cast<CycleCollectedJSContext*>(aData);
-  ccjs->QueueFinalizationRegistryForCleanup(aRegistry);
+void FinalizationRegistryCleanup::QueueCallback(JSFunction* aDoCleanup,
+                                                JSObject* aIncumbentGlobal,
+                                                void* aData) {
+  FinalizationRegistryCleanup* cleanup =
+      static_cast<FinalizationRegistryCleanup*>(aData);
+  cleanup->QueueCallback(aDoCleanup, aIncumbentGlobal);
 }
 
-void CycleCollectedJSContext::QueueFinalizationRegistryForCleanup(
-    JSObject* aRegistry) {
-  bool firstRegistry = mFinalizationRegistriesToCleanUp.empty();
-  MOZ_ALWAYS_TRUE(mFinalizationRegistriesToCleanUp.append(aRegistry));
-  if (firstRegistry) {
-    RefPtr<CleanupFinalizationRegistriesRunnable> cleanup =
-        new CleanupFinalizationRegistriesRunnable(this);
+void FinalizationRegistryCleanup::QueueCallback(JSFunction* aDoCleanup,
+                                                JSObject* aIncumbentGlobal) {
+  bool firstCallback = mCallbacks.empty();
+
+  MOZ_ALWAYS_TRUE(mCallbacks.append(Callback{aDoCleanup, aIncumbentGlobal}));
+
+  if (firstCallback) {
+    RefPtr<CleanupRunnable> cleanup = new CleanupRunnable(this);
     NS_DispatchToCurrentThread(cleanup.forget());
   }
 }
 
+void FinalizationRegistryCleanup::DoCleanup() {
+  if (mCallbacks.empty()) {
+    return;
+  }
+
+  JS::RootingContext* cx = mContext->RootingCx();
+
+  JS::Rooted<CallbackVector> callbacks(cx);
+  std::swap(callbacks.get(), mCallbacks.get());
+
+  for (const Callback& callback : callbacks) {
+    JS::RootedObject functionObj(
+        cx, JS_GetFunctionObject(callback.mCallbackFunction));
+    JS::RootedObject globalObj(cx, JS::GetNonCCWObjectGlobal(functionObj));
+
+    nsIGlobalObject* incumbentGlobal =
+        xpc::NativeGlobal(callback.mIncumbentGlobal);
+    if (!incumbentGlobal) {
+      continue;
+    }
+
+    RefPtr<FinalizationRegistryCleanupCallback> cleanupCallback(
+        new FinalizationRegistryCleanupCallback(functionObj, globalObj, nullptr,
+                                                incumbentGlobal));
+
+    nsIGlobalObject* global =
+        xpc::NativeGlobal(cleanupCallback->CallbackPreserveColor());
+    if (global) {
+      cleanupCallback->Call("FinalizationRegistryCleanup::DoCleanup");
+    }
+  }
+}
+
+void FinalizationRegistryCleanup::Callback::trace(JSTracer* trc) {
+  JS::UnsafeTraceRoot(trc, &mCallbackFunction, "mCallbackFunction");
+  JS::UnsafeTraceRoot(trc, &mIncumbentGlobal, "mIncumbentGlobal");
+}
+
 }  // namespace mozilla
diff --git a/xpcom/base/CycleCollectedJSContext.h b/xpcom/base/CycleCollectedJSContext.h
index 84b3ea3726..b50d4cb5c2 100644
--- a/xpcom/base/CycleCollectedJSContext.h
+++ b/xpcom/base/CycleCollectedJSContext.h
@@ -30,6 +30,7 @@ class nsWrapperCache;
 namespace mozilla {
 class AutoSlowOperation;
 
+class CycleCollectedJSContext;
 class CycleCollectedJSRuntime;
 
 namespace dom {
@@ -83,6 +84,40 @@ class MicroTaskRunnable {
   virtual ~MicroTaskRunnable() = default;
 };
 
+// Support for JS FinalizationRegistry objects, which allow a JS callback to be
+// registered that is called when objects die.
+//
+// We keep a vector of functions that call back into the JS engine along
+// with their associated incumbent globals, one per FinalizationRegistry object
+// that has pending cleanup work. These are run in their own task.
+class FinalizationRegistryCleanup {
+ public:
+  explicit FinalizationRegistryCleanup(CycleCollectedJSContext* aContext);
+  void Init();
+  void Destroy();
+  void QueueCallback(JSFunction* aDoCleanup, JSObject* aIncumbentGlobal);
+  MOZ_CAN_RUN_SCRIPT void DoCleanup();
+
+ private:
+  static void QueueCallback(JSFunction* aDoCleanup, JSObject* aIncumbentGlobal,
+                            void* aData);
+
+  class CleanupRunnable;
+
+  struct Callback {
+    JSFunction* mCallbackFunction;
+    JSObject* mIncumbentGlobal;
+    void trace(JSTracer* trc);
+  };
+
+  // This object is part of CycleCollectedJSContext, so it's safe to have a raw
+  // pointer to its containing context here.
+  CycleCollectedJSContext* mContext;
+
+  using CallbackVector = JS::GCVector<Callback, 0, InfallibleAllocPolicy>;
+  JS::PersistentRooted<CallbackVector> mCallbacks;
+};
+
 class CycleCollectedJSContext : dom::PerThreadAtomCache, private JS::JobQueue {
   friend class CycleCollectedJSRuntime;
 
@@ -260,10 +295,6 @@ class CycleCollectedJSContext : dom::PerThreadAtomCache, private JS::JobQueue {
   class SavedMicroTaskQueue;
   js::UniquePtr<SavedJobQueue> saveJobQueue(JSContext*) override;
 
-  static void CleanupFinalizationRegistryCallback(JSObject* aRegistry,
-                                                  void* aData);
-  void QueueFinalizationRegistryForCleanup(JSObject* aRegistry);
-
  private:
   CycleCollectedJSRuntime* mRuntime;
 
@@ -338,14 +369,7 @@ class CycleCollectedJSContext : dom::PerThreadAtomCache, private JS::JobQueue {
     PromiseArray mUnhandledRejections;
   };
 
-  // Support for JS FinalizationRegistry objects.
-  //
-  // These allow a JS callback to be registered that is called when an object
-  // dies. The browser part of the implementation keeps a vector of
-  // FinalizationRegistries with pending callbacks here.
-  friend class CleanupFinalizationRegistriesRunnable;
-  using ObjectVector = JS::GCVector<JSObject*, 0, InfallibleAllocPolicy>;
-  JS::PersistentRooted<ObjectVector> mFinalizationRegistriesToCleanUp;
+  FinalizationRegistryCleanup mFinalizationRegistryCleanup;
 };
 
 class MOZ_STACK_CLASS nsAutoMicroTask {
diff --git a/xpcom/base/CycleCollectedJSRuntime.cpp b/xpcom/base/CycleCollectedJSRuntime.cpp
index a1e101cf9c..27b9e199c1 100644
--- a/xpcom/base/CycleCollectedJSRuntime.cpp
+++ b/xpcom/base/CycleCollectedJSRuntime.cpp
@@ -52,29 +52,35 @@
 // traversed.
 
 #include "mozilla/CycleCollectedJSRuntime.h"
+
 #include <algorithm>
+#include <utility>
+
+#include "GeckoProfiler.h"
+#include "js/Debug.h"
+#include "js/friend/DumpFunctions.h"  // js::DumpHeap
+#include "js/GCAPI.h"
+#include "js/HeapAPI.h"
+#include "js/Object.h"    // JS::GetClass, JS::GetCompartment, JS::GetPrivate
+#include "js/Warnings.h"  // JS::SetWarningReporter
+#include "jsfriendapi.h"
 #include "mozilla/ArrayUtils.h"
 #include "mozilla/AutoRestore.h"
 #include "mozilla/CycleCollectedJSContext.h"
-#include "mozilla/Move.h"
+#include "mozilla/DebuggerOnGCRunnable.h"
 #include "mozilla/MemoryReporting.h"
 #include "mozilla/Sprintf.h"
 #include "mozilla/Telemetry.h"
 #include "mozilla/TimelineConsumers.h"
 #include "mozilla/TimelineMarker.h"
 #include "mozilla/Unused.h"
-#include "mozilla/DebuggerOnGCRunnable.h"
 #include "mozilla/dom/DOMJSClass.h"
+#include "mozilla/dom/JSExecutionManager.h"
 #include "mozilla/dom/ProfileTimelineMarkerBinding.h"
 #include "mozilla/dom/Promise.h"
 #include "mozilla/dom/PromiseBinding.h"
 #include "mozilla/dom/PromiseDebugging.h"
 #include "mozilla/dom/ScriptSettings.h"
-#include "js/Debug.h"
-#include "js/GCAPI.h"
-#include "js/HeapAPI.h"
-#include "js/Warnings.h"  // JS::SetWarningReporter
-#include "jsfriendapi.h"
 #include "nsContentUtils.h"
 #include "nsCycleCollectionNoteRootCallback.h"
 #include "nsCycleCollectionParticipant.h"
@@ -82,9 +88,8 @@
 #include "nsDOMJSUtils.h"
 #include "nsExceptionHandler.h"
 #include "nsJSUtils.h"
-#include "nsWrapperCache.h"
 #include "nsStringBuffer.h"
-#include "GeckoProfiler.h"
+#include "nsWrapperCache.h"
 
 #ifdef MOZ_GECKO_PROFILER
 #  include "ProfilerMarkerPayload.h"
@@ -432,7 +437,8 @@ bool TraversalTracer::onChild(const JS::GCCellPtr& aThing) {
   return true;
 }
 
-static void NoteJSChildGrayWrapperShim(void* aData, JS::GCCellPtr aThing) {
+static void NoteJSChildGrayWrapperShim(void* aData, JS::GCCellPtr aThing,
+                                       const JS::AutoRequireNoGC& nogc) {
   TraversalTracer* trc = static_cast<TraversalTracer*>(aData);
   trc->onChild(aThing);
 }
@@ -684,6 +690,8 @@ CycleCollectedJSRuntime::CycleCollectedJSRuntime(JSContext* aCx)
 
   JS_SetObjectsTenuredCallback(aCx, JSObjectsTenuredCb, this);
   JS::SetOutOfMemoryCallback(aCx, OutOfMemoryCallback, this);
+  JS::SetWaitCallback(mJSRuntime, BeforeWaitCallback, AfterWaitCallback,
+                      sizeof(dom::AutoYieldJSThreadExecution));
   JS::SetWarningReporter(aCx, MozCrashWarningReporter);
 
   js::AutoEnterOOMUnsafeRegion::setAnnotateOOMAllocationSizeCallback(
@@ -767,8 +775,8 @@ void CycleCollectedJSRuntime::DescribeGCThing(
   uint64_t compartmentAddress = 0;
   if (aThing.is<JSObject>()) {
     JSObject* obj = &aThing.as<JSObject>();
-    compartmentAddress = (uint64_t)js::GetObjectCompartment(obj);
-    const JSClass* clasp = js::GetObjectClass(obj);
+    compartmentAddress = (uint64_t)JS::GetCompartment(obj);
+    const JSClass* clasp = JS::GetClass(obj);
 
     // Give the subclass a chance to do something
     if (DescribeCustomObjects(obj, clasp, name)) {
@@ -806,7 +814,7 @@ void CycleCollectedJSRuntime::NoteGCThingXPCOMChildren(
     const JSClass* aClasp, JSObject* aObj,
     nsCycleCollectionTraversalCallback& aCb) const {
   MOZ_ASSERT(aClasp);
-  MOZ_ASSERT(aClasp == js::GetObjectClass(aObj));
+  MOZ_ASSERT(aClasp == JS::GetClass(aObj));
 
   JS::Rooted<JSObject*> obj(RootingCx(), aObj);
 
@@ -819,8 +827,8 @@ void CycleCollectedJSRuntime::NoteGCThingXPCOMChildren(
   //     that do hold a strong reference, but that might not be possible.
   if (aClasp->flags & JSCLASS_HAS_PRIVATE &&
       aClasp->flags & JSCLASS_PRIVATE_IS_NSISUPPORTS) {
-    NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(aCb, "js::GetObjectPrivate(obj)");
-    aCb.NoteXPCOMChild(static_cast<nsISupports*>(js::GetObjectPrivate(obj)));
+    NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(aCb, "JS::GetPrivate(obj)");
+    aCb.NoteXPCOMChild(static_cast<nsISupports*>(JS::GetPrivate(obj)));
     return;
   }
 
@@ -877,7 +885,7 @@ void CycleCollectedJSRuntime::TraverseGCThing(
 
   if (aThing.is<JSObject>()) {
     JSObject* obj = &aThing.as<JSObject>();
-    NoteGCThingXPCOMChildren(js::GetObjectClass(obj), obj, aCb);
+    NoteGCThingXPCOMChildren(JS::GetClass(obj), obj, aCb);
   }
 }
 
@@ -920,8 +928,8 @@ void CycleCollectedJSRuntime::TraverseZone(
 }
 
 /* static */
-void CycleCollectedJSRuntime::TraverseObjectShim(void* aData,
-                                                 JS::GCCellPtr aThing) {
+void CycleCollectedJSRuntime::TraverseObjectShim(
+    void* aData, JS::GCCellPtr aThing, const JS::AutoRequireNoGC& nogc) {
   TraverseObjectShimClosure* closure =
       static_cast<TraverseObjectShimClosure*>(aData);
 
@@ -999,17 +1007,15 @@ void CycleCollectedJSRuntime::GCSliceCallback(JSContext* aContext,
 #ifdef MOZ_GECKO_PROFILER
   if (profiler_thread_is_being_profiled()) {
     if (aProgress == JS::GC_CYCLE_END) {
-      profiler_add_marker(
-          "GCMajor", JS::ProfilingCategoryPair::GCCC,
-          MakeUnique<GCMajorMarkerPayload>(aDesc.startTime(aContext),
-                                           aDesc.endTime(aContext),
-                                           aDesc.formatJSONProfiler(aContext)));
+      PROFILER_ADD_MARKER_WITH_PAYLOAD(
+          "GCMajor", GCCC, GCMajorMarkerPayload,
+          (aDesc.startTime(aContext), aDesc.endTime(aContext),
+           aDesc.formatJSONProfiler(aContext)));
     } else if (aProgress == JS::GC_SLICE_END) {
-      profiler_add_marker(
-          "GCSlice", JS::ProfilingCategoryPair::GCCC,
-          MakeUnique<GCSliceMarkerPayload>(
-              aDesc.lastSliceStart(aContext), aDesc.lastSliceEnd(aContext),
-              aDesc.sliceToJSONProfiler(aContext)));
+      PROFILER_ADD_MARKER_WITH_PAYLOAD(
+          "GCSlice", GCCC, GCSliceMarkerPayload,
+          (aDesc.lastSliceStart(aContext), aDesc.lastSliceEnd(aContext),
+           aDesc.sliceToJSONProfiler(aContext)));
     }
   }
 #endif
@@ -1088,10 +1094,10 @@ void CycleCollectedJSRuntime::GCNurseryCollectionCallback(
 #ifdef MOZ_GECKO_PROFILER
   else if (aProgress == JS::GCNurseryProgress::GC_NURSERY_COLLECTION_END &&
            profiler_thread_is_being_profiled()) {
-    profiler_add_marker("GCMinor", JS::ProfilingCategoryPair::GCCC,
-                        MakeUnique<GCMinorMarkerPayload>(
-                            self->mLatestNurseryCollectionStart,
-                            TimeStamp::Now(), JS::MinorGcToJSON(aContext)));
+    PROFILER_ADD_MARKER_WITH_PAYLOAD(
+        "GCMinor", GCCC, GCMinorMarkerPayload,
+        (self->mLatestNurseryCollectionStart, TimeStamp::Now(),
+         JS::MinorGcToJSON(aContext)));
   }
 #endif
 
@@ -1111,6 +1117,22 @@ void CycleCollectedJSRuntime::OutOfMemoryCallback(JSContext* aContext,
   self->OnOutOfMemory();
 }
 
+/* static */
+void* CycleCollectedJSRuntime::BeforeWaitCallback(uint8_t* aMemory) {
+  MOZ_ASSERT(aMemory);
+
+  // aMemory is stack allocated memory to contain our RAII object. This allows
+  // for us to avoid allocations on the heap during this callback.
+  return new (aMemory) dom::AutoYieldJSThreadExecution;
+}
+
+/* static */
+void CycleCollectedJSRuntime::AfterWaitCallback(void* aCookie) {
+  MOZ_ASSERT(aCookie);
+  static_cast<dom::AutoYieldJSThreadExecution*>(aCookie)
+      ->~AutoYieldJSThreadExecution();
+}
+
 struct JsGcTracer : public TraceCallbacks {
   virtual void Trace(JS::Heap<JS::Value>* aPtr, const char* aName,
                      void* aClosure) const override {
diff --git a/xpcom/base/CycleCollectedJSRuntime.h b/xpcom/base/CycleCollectedJSRuntime.h
index 1a8a825f4b..70893b4b4d 100644
--- a/xpcom/base/CycleCollectedJSRuntime.h
+++ b/xpcom/base/CycleCollectedJSRuntime.h
@@ -196,7 +196,8 @@ class CycleCollectedJSRuntime {
 
   void TraverseZone(JS::Zone* aZone, nsCycleCollectionTraversalCallback& aCb);
 
-  static void TraverseObjectShim(void* aData, JS::GCCellPtr aThing);
+  static void TraverseObjectShim(void* aData, JS::GCCellPtr aThing,
+                                 const JS::AutoRequireNoGC& nogc);
 
   void TraverseNativeRoots(nsCycleCollectionNoteRootCallback& aCb);
 
@@ -213,6 +214,9 @@ class CycleCollectedJSRuntime {
 
   static bool ContextCallback(JSContext* aCx, unsigned aOperation, void* aData);
 
+  static void* BeforeWaitCallback(uint8_t* aMemory);
+  static void AfterWaitCallback(void* aCookie);
+
   virtual void TraceNativeBlackRoots(JSTracer* aTracer){};
   void TraceNativeGrayRoots(JSTracer* aTracer,
                             JSHolderMap::WhichHolders aWhich);
diff --git a/xpcom/base/DebuggerOnGCRunnable.cpp b/xpcom/base/DebuggerOnGCRunnable.cpp
index f1df084946..f354ad72e9 100644
--- a/xpcom/base/DebuggerOnGCRunnable.cpp
+++ b/xpcom/base/DebuggerOnGCRunnable.cpp
@@ -4,11 +4,12 @@
 
 #include "mozilla/DebuggerOnGCRunnable.h"
 
-#include "mozilla/dom/ScriptSettings.h"
-#include "mozilla/CycleCollectedJSContext.h"
-#include "mozilla/Move.h"
-#include "mozilla/SystemGroup.h"
+#include <utility>
+
 #include "js/Debug.h"
+#include "mozilla/CycleCollectedJSContext.h"
+#include "mozilla/SystemGroup.h"
+#include "mozilla/dom/ScriptSettings.h"
 
 namespace mozilla {
 
diff --git a/xpcom/base/DebuggerOnGCRunnable.h b/xpcom/base/DebuggerOnGCRunnable.h
index d7926a04e7..88e69837db 100644
--- a/xpcom/base/DebuggerOnGCRunnable.h
+++ b/xpcom/base/DebuggerOnGCRunnable.h
@@ -5,10 +5,11 @@
 #ifndef mozilla_DebuggerOnGCRunnable_h
 #define mozilla_DebuggerOnGCRunnable_h
 
-#include "nsThreadUtils.h"
+#include <utility>
+
 #include "js/GCAPI.h"
-#include "mozilla/Move.h"
 #include "mozilla/UniquePtr.h"
+#include "nsThreadUtils.h"
 
 namespace mozilla {
 
diff --git a/xpcom/base/Logging.cpp b/xpcom/base/Logging.cpp
index 5f0b3fcb2e..a68ada533f 100644
--- a/xpcom/base/Logging.cpp
+++ b/xpcom/base/Logging.cpp
@@ -391,10 +391,9 @@ class LogModuleManager {
     }
 
 #ifdef MOZ_GECKO_PROFILER
-    if (mAddProfilerMarker && profiler_is_active()) {
-      profiler_add_marker(
-          "LogMessages", JS::ProfilingCategoryPair::OTHER,
-          MakeUnique<LogMarkerPayload>(aName, buffToWrite, TimeStamp::Now()));
+    if (mAddProfilerMarker && profiler_can_accept_markers()) {
+      PROFILER_ADD_MARKER_WITH_PAYLOAD("LogMessages", OTHER, LogMarkerPayload,
+                                       (aName, buffToWrite, TimeStamp::Now()));
     }
 #endif
 
diff --git a/xpcom/base/MemoryTelemetry.cpp b/xpcom/base/MemoryTelemetry.cpp
index 3c9a41e9c7..d66e13efd2 100644
--- a/xpcom/base/MemoryTelemetry.cpp
+++ b/xpcom/base/MemoryTelemetry.cpp
@@ -5,7 +5,6 @@
 #include "MemoryTelemetry.h"
 #include "nsMemoryReporterManager.h"
 
-#include "GCTelemetry.h"
 #include "mozilla/ClearOnShutdown.h"
 #include "mozilla/Result.h"
 #include "mozilla/ResultExtensions.h"
@@ -46,19 +45,6 @@ static constexpr const char* kTopicCycleCollectorBegin =
 // How long to wait in millis for all the child memory reports to come in
 static constexpr uint32_t kTotalMemoryCollectorTimeout = 200;
 
-static Result<nsCOMPtr<mozIGCTelemetry>, nsresult> GetGCTelemetry() {
-  nsresult rv;
-
-  nsCOMPtr<mozIGCTelemetryJSM> jsm =
-      do_ImportModule("resource://gre/modules/GCTelemetry.jsm", &rv);
-  MOZ_TRY(rv);
-
-  nsCOMPtr<mozIGCTelemetry> gcTelemetry;
-  MOZ_TRY(jsm->GetGCTelemetry(getter_AddRefs(gcTelemetry)));
-
-  return std::move(gcTelemetry);
-}
-
 namespace {
 
 enum class PrevValue : uint32_t {
@@ -140,13 +126,6 @@ nsresult MemoryTelemetry::DelayedInit() {
 
   GatherReports();
 
-  if (Telemetry::CanRecordExtended()) {
-    nsCOMPtr<mozIGCTelemetry> gcTelemetry;
-    MOZ_TRY_VAR(gcTelemetry, GetGCTelemetry());
-
-    MOZ_TRY(gcTelemetry->Init());
-  }
-
   return NS_OK;
 }
 
@@ -156,13 +135,6 @@ nsresult MemoryTelemetry::Shutdown() {
 
   obs->RemoveObserver(this, kTopicCycleCollectorBegin);
 
-  if (Telemetry::CanRecordExtended()) {
-    nsCOMPtr<mozIGCTelemetry> gcTelemetry;
-    MOZ_TRY_VAR(gcTelemetry, GetGCTelemetry());
-
-    MOZ_TRY(gcTelemetry->Shutdown());
-  }
-
   return NS_OK;
 }
 
diff --git a/xpcom/base/OwningNonNull.h b/xpcom/base/OwningNonNull.h
index 3f31200aaf..5115949cbc 100644
--- a/xpcom/base/OwningNonNull.h
+++ b/xpcom/base/OwningNonNull.h
@@ -7,7 +7,7 @@
 #ifndef mozilla_OwningNonNull_h
 #define mozilla_OwningNonNull_h
 
-#include "nsAutoPtr.h"
+#include "nsCOMPtr.h"
 #include "nsCycleCollectionNoteChild.h"
 
 namespace mozilla {
diff --git a/xpcom/base/nsCOMPtr.h b/xpcom/base/nsCOMPtr.h
index a2cc70c4d8..ed533dd5db 100644
--- a/xpcom/base/nsCOMPtr.h
+++ b/xpcom/base/nsCOMPtr.h
@@ -18,17 +18,17 @@
  *                      -- scc
  */
 
+#include <type_traits>
+#include <utility>
+
 #include "mozilla/AlreadyAddRefed.h"
 #include "mozilla/Assertions.h"
 #include "mozilla/Attributes.h"
-#include "mozilla/Move.h"
+#include "mozilla/RefPtr.h"
 #include "mozilla/TypeTraits.h"
-
+#include "nsCycleCollectionNoteChild.h"
 #include "nsDebug.h"  // for |NS_ASSERTION|
 #include "nsISupportsUtils.h"  // for |nsresult|, |NS_ADDREF|, |NS_GET_TEMPLATE_IID| et al
-#include "mozilla/RefPtr.h"
-
-#include "nsCycleCollectionNoteChild.h"
 
 /*
  * WARNING: This file defines several macros for internal use only. These
@@ -202,8 +202,7 @@ namespace mozilla {
 // variety of smart pointer types in addition to raw pointers. These types
 // include RefPtr<>, nsCOMPtr<>, and OwningNonNull<>.
 template <class T>
-using PointedToType =
-    typename mozilla::RemovePointer<decltype(&*mozilla::DeclVal<T>())>::Type;
+using PointedToType = std::remove_pointer_t<decltype(&*std::declval<T>())>;
 }  // namespace mozilla
 
 #ifdef NSCAP_FEATURE_USE_BASE
@@ -1507,4 +1506,20 @@ RefPtr<T> ToRefPtr(nsCOMPtr<T>&& aObj) {
   return aObj.forget();
 }
 
+// Integration with ResultExtensions.h
+template <typename R>
+auto ResultRefAsParam(nsCOMPtr<R>& aResult) {
+  return getter_AddRefs(aResult);
+}
+
+namespace mozilla::detail {
+template <typename T>
+struct outparam_as_pointer;
+
+template <typename T>
+struct outparam_as_pointer<nsGetterAddRefs<T>> {
+  using type = T**;
+};
+}  // namespace mozilla::detail
+
 #endif  // !defined(nsCOMPtr_h___)
diff --git a/xpcom/base/nsCycleCollector.cpp b/xpcom/base/nsCycleCollector.cpp
index 4d9ede8b90..5278abc52a 100644
--- a/xpcom/base/nsCycleCollector.cpp
+++ b/xpcom/base/nsCycleCollector.cpp
@@ -21,7 +21,7 @@
 // unlinking them they will self-destruct (since a garbage cycle is
 // only keeping itself alive with internal links, by definition).
 //
-// Snow-white is an addition to the original algorithm. Snow-white object
+// Snow-white is an addition to the original algorithm. A snow-white node
 // has reference count zero and is just waiting for deletion.
 //
 // Grey nodes are being scanned. Nodes that turn grey will turn
@@ -158,39 +158,40 @@
 #include "mozilla/HashTable.h"
 #include "mozilla/HoldDropJSObjects.h"
 /* This must occur *after* base/process_util.h to avoid typedefs conflicts. */
-#include "mozilla/LinkedList.h"
-#include "mozilla/MemoryReporting.h"
-#include "mozilla/Move.h"
-#include "mozilla/MruCache.h"
-#include "mozilla/SegmentedVector.h"
-
-#include "nsCycleCollectionParticipant.h"
-#include "nsCycleCollectionNoteRootCallback.h"
-#include "nsDeque.h"
-#include "nsExceptionHandler.h"
-#include "nsCycleCollector.h"
-#include "nsThreadUtils.h"
-#include "nsXULAppAPI.h"
-#include "prenv.h"
-#include "nsPrintfCString.h"
-#include "nsTArray.h"
-#include "nsIConsoleService.h"
-#include "mozilla/Attributes.h"
-#include "nsICycleCollectorListener.h"
-#include "nsISerialEventTarget.h"
-#include "nsIMemoryReporter.h"
-#include "nsIFile.h"
-#include "nsDumpUtils.h"
-#include "xpcpublic.h"
-#include "GeckoProfiler.h"
 #include <stdint.h>
 #include <stdio.h>
 
+#include <utility>
+
+#include "GeckoProfiler.h"
+#include "mozilla/Attributes.h"
 #include "mozilla/AutoGlobalTimelineMarker.h"
 #include "mozilla/Likely.h"
-//#include "mozilla/PoisonIOInterposer.h"
+#include "mozilla/LinkedList.h"
+#include "mozilla/MemoryReporting.h"
+#include "mozilla/MruCache.h"
+#include "mozilla/PoisonIOInterposer.h"
+#include "mozilla/SegmentedVector.h"
 #include "mozilla/Telemetry.h"
 #include "mozilla/ThreadLocal.h"
+#include "mozilla/UniquePtr.h"
+#include "nsCycleCollectionNoteRootCallback.h"
+#include "nsCycleCollectionParticipant.h"
+#include "nsCycleCollector.h"
+#include "nsDeque.h"
+#include "nsDumpUtils.h"
+#include "nsExceptionHandler.h"
+#include "nsIConsoleService.h"
+#include "nsICycleCollectorListener.h"
+#include "nsIFile.h"
+#include "nsIMemoryReporter.h"
+#include "nsISerialEventTarget.h"
+#include "nsPrintfCString.h"
+#include "nsTArray.h"
+#include "nsThreadUtils.h"
+#include "nsXULAppAPI.h"
+#include "prenv.h"
+#include "xpcpublic.h"
 
 using namespace mozilla;
 
@@ -519,9 +520,9 @@ enum NodeColor { black, white, grey };
 // This structure should be kept as small as possible; we may expect
 // hundreds of thousands of them to be allocated and touched
 // repeatedly during each cycle collection.
-
 class PtrInfo final {
  public:
+  // mParticipant knows a more concrete type.
   void* mPointer;
   nsCycleCollectionParticipant* mParticipant;
   uint32_t mColor : 2;
@@ -1008,7 +1009,7 @@ struct nsPurpleBuffer {
   // (1) if !aAsyncSnowWhiteFreeing and nsPurpleBufferEntry::mRefCnt is 0 or
   // (2) if nsXPCOMCycleCollectionParticipant::CanSkip() for the obj or
   // (3) if nsPurpleBufferEntry::mRefCnt->IsPurple() is false.
-  // (4) If removeChildlessNodes is true, then any nodes in the purple buffer
+  // (4) If aRemoveChildlessNodes is true, then any nodes in the purple buffer
   //     that will have no children in the cycle collector graph will also be
   //     removed. CanSkip() may be run on these children.
   void RemoveSkippable(nsCycleCollector* aCollector, js::SliceBudget& aBudget,
@@ -1107,7 +1108,7 @@ class nsCycleCollector : public nsIMemoryReporter {
 
   ccPhase mIncrementalPhase;
   CCGraph mGraph;
-  nsAutoPtr<CCGraphBuilder> mBuilder;
+  UniquePtr<CCGraphBuilder> mBuilder;
   RefPtr<nsCycleCollectorLogger> mLogger;
 
 #ifdef DEBUG
@@ -1826,7 +1827,7 @@ class CCGraphBuilder final : public nsCycleCollectionTraversalCallback,
   nsCString mNextEdgeName;
   RefPtr<nsCycleCollectorLogger> mLogger;
   bool mMergeZones;
-  nsAutoPtr<NodePool::Enumerator> mCurrNode;
+  UniquePtr<NodePool::Enumerator> mCurrNode;
   uint32_t mNoteChildCount;
 
   struct PtrInfoCache : public MruCache<void*, PtrInfo*, PtrInfoCache, 491> {
@@ -2032,7 +2033,7 @@ void CCGraphBuilder::DoneAddingRoots() {
   // We've finished adding roots, and everything in the graph is a root.
   mGraph.mRootCount = mGraph.MapCount();
 
-  mCurrNode = new NodePool::Enumerator(mGraph.mNodes);
+  mCurrNode = MakeUnique<NodePool::Enumerator>(mGraph.mNodes);
 }
 
 MOZ_NEVER_INLINE bool CCGraphBuilder::BuildGraph(SliceBudget& aBudget) {
@@ -2415,6 +2416,7 @@ class SnowWhiteKiller : public TraceCallbacks {
     }
   }
 
+ private:
   void MaybeKillObject(SnowWhiteObject& aObject) {
     if (!aObject.mRefCnt->get() && !aObject.mRefCnt->IsInPurpleBuffer()) {
       mCollector->RemoveObjectFromGraph(aObject.mPointer);
@@ -2427,6 +2429,7 @@ class SnowWhiteKiller : public TraceCallbacks {
     }
   }
 
+ public:
   bool Visit(nsPurpleBuffer& aBuffer, nsPurpleBufferEntry* aEntry) {
     if (mBudget) {
       if (mBudget->isOverBudget()) {
@@ -3587,8 +3590,8 @@ void nsCycleCollector::BeginCollection(
   mResults.mMergedZones = mergeZones;
 
   MOZ_ASSERT(!mBuilder, "Forgot to clear mBuilder");
-  mBuilder =
-      new CCGraphBuilder(mGraph, mResults, mCCJSRuntime, mLogger, mergeZones);
+  mBuilder = MakeUnique<CCGraphBuilder>(mGraph, mResults, mCCJSRuntime, mLogger,
+                                        mergeZones);
   timeLog.Checkpoint("BeginCollection prepare graph builder");
 
   if (mCCJSRuntime) {
diff --git a/xpcom/base/nsErrorService.cpp b/xpcom/base/nsErrorService.cpp
index 330f59644e..0bcef2b6e6 100644
--- a/xpcom/base/nsErrorService.cpp
+++ b/xpcom/base/nsErrorService.cpp
@@ -4,7 +4,6 @@
 
 #include "nsErrorService.h"
 #include "nsCRTGlue.h"
-#include "nsAutoPtr.h"
 #include "mozilla/StaticPtr.h"
 #include "mozilla/ClearOnShutdown.h"
 
diff --git a/xpcom/base/nsISupportsImpl.h b/xpcom/base/nsISupportsImpl.h
index 33f38c4d20..84a9edf641 100644
--- a/xpcom/base/nsISupportsImpl.h
+++ b/xpcom/base/nsISupportsImpl.h
@@ -17,6 +17,7 @@
 #include "nsDebug.h"
 #include "nsXPCOM.h"
 #include <atomic>
+#include <type_traits>
 #include "mozilla/Attributes.h"
 #include "mozilla/Assertions.h"
 #include "mozilla/Atomics.h"
@@ -1202,12 +1203,12 @@ namespace mozilla {
 class Runnable;
 }  // namespace mozilla
 
-#define NS_IMPL_ADDREF_INHERITED_GUTS(Class, Super)                 \
-  MOZ_ASSERT_TYPE_OK_FOR_REFCOUNTING(Class)                         \
-  nsrefcnt r = Super::AddRef();                                     \
-  if (!mozilla::IsConvertible<Class*, mozilla::Runnable*>::value) { \
-    NS_LOG_ADDREF(this, r, #Class, sizeof(*this));                  \
-  }                                                                 \
+#define NS_IMPL_ADDREF_INHERITED_GUTS(Class, Super)         \
+  MOZ_ASSERT_TYPE_OK_FOR_REFCOUNTING(Class)                 \
+  nsrefcnt r = Super::AddRef();                             \
+  if (!std::is_convertible_v<Class*, mozilla::Runnable*>) { \
+    NS_LOG_ADDREF(this, r, #Class, sizeof(*this));          \
+  }                                                         \
   return r /* Purposefully no trailing semicolon */
 
 #define NS_IMPL_ADDREF_INHERITED(Class, Super)                  \
@@ -1215,11 +1216,11 @@ class Runnable;
     NS_IMPL_ADDREF_INHERITED_GUTS(Class, Super);                \
   }
 
-#define NS_IMPL_RELEASE_INHERITED_GUTS(Class, Super)                \
-  nsrefcnt r = Super::Release();                                    \
-  if (!mozilla::IsConvertible<Class*, mozilla::Runnable*>::value) { \
-    NS_LOG_RELEASE(this, r, #Class);                                \
-  }                                                                 \
+#define NS_IMPL_RELEASE_INHERITED_GUTS(Class, Super)        \
+  nsrefcnt r = Super::Release();                            \
+  if (!std::is_convertible_v<Class*, mozilla::Runnable*>) { \
+    NS_LOG_RELEASE(this, r, #Class);                        \
+  }                                                         \
   return r /* Purposefully no trailing semicolon */
 
 #define NS_IMPL_RELEASE_INHERITED(Class, Super)                  \
diff --git a/xpcom/base/nsMemoryReporterManager.cpp b/xpcom/base/nsMemoryReporterManager.cpp
index 5030dab46e..299a8b062b 100644
--- a/xpcom/base/nsMemoryReporterManager.cpp
+++ b/xpcom/base/nsMemoryReporterManager.cpp
@@ -3,7 +3,6 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #include "nsAtomTable.h"
-#include "nsAutoPtr.h"
 #include "nsCOMPtr.h"
 #include "nsCOMArray.h"
 #include "nsPrintfCString.h"
@@ -2049,9 +2048,8 @@ void nsMemoryReporterManager::EndProcessReport(uint32_t aGeneration,
   while (s->mNumProcessesRunning < s->mConcurrencyLimit &&
          !s->mChildrenPending.IsEmpty()) {
     // Pop last element from s->mChildrenPending
-    RefPtr<MemoryReportingProcess> nextChild;
-    nextChild.swap(s->mChildrenPending.LastElement());
-    s->mChildrenPending.TruncateLength(s->mChildrenPending.Length() - 1);
+    const RefPtr<MemoryReportingProcess> nextChild =
+        s->mChildrenPending.PopLastElement();
     // Start report (if the child is still alive).
     if (StartChildReport(nextChild, s)) {
       ++s->mNumProcessesRunning;
diff --git a/xpcom/base/nsMessageLoop.cpp b/xpcom/base/nsMessageLoop.cpp
index eeaf00d088..5cd79c1959 100644
--- a/xpcom/base/nsMessageLoop.cpp
+++ b/xpcom/base/nsMessageLoop.cpp
@@ -10,7 +10,6 @@
 #include "nsIRunnable.h"
 #include "nsITimer.h"
 #include "nsCOMPtr.h"
-#include "nsAutoPtr.h"
 #include "nsComponentManagerUtils.h"
 #include "nsThreadUtils.h"
 
diff --git a/xpcom/base/nsTraceRefcnt.cpp b/xpcom/base/nsTraceRefcnt.cpp
index 7254272b77..a9277abfb8 100644
--- a/xpcom/base/nsTraceRefcnt.cpp
+++ b/xpcom/base/nsTraceRefcnt.cpp
@@ -35,7 +35,7 @@
 #include "mozilla/Atomics.h"
 #include "mozilla/AutoRestore.h"
 #include "mozilla/BlockingResourceBase.h"
-//#include "mozilla/PoisonIOInterposer.h"
+#include "mozilla/PoisonIOInterposer.h"
 #include "mozilla/UniquePtr.h"
 
 #include <string>
@@ -201,43 +201,7 @@ static void AssertActivityIsLegal() {
 
 ////////////////////////////////////////////////////////////////////////////////
 
-class CodeAddressServiceStringTable final {
- public:
-  CodeAddressServiceStringTable() : mSet(32) {}
-
-  const char* Intern(const char* aString) {
-    nsCharPtrHashKey* e = mSet.PutEntry(aString);
-    return e->GetKey();
-  }
-
-  size_t SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const {
-    return mSet.SizeOfExcludingThis(aMallocSizeOf);
-  }
-
- private:
-  typedef nsTHashtable<nsCharPtrHashKey> StringSet;
-  StringSet mSet;
-};
-
-struct CodeAddressServiceStringAlloc final {
-  static char* copy(const char* aStr) { return strdup(aStr); }
-  static void free(char* aPtr) { ::free(aPtr); }
-};
-
-// WalkTheStack does not hold any locks needed by MozDescribeCodeAddress, so
-// this class does not need to do anything.
-struct CodeAddressServiceLock final {
-  static void Unlock() {}
-  static void Lock() {}
-  static bool IsLocked() { return true; }
-};
-
-typedef mozilla::CodeAddressService<CodeAddressServiceStringTable,
-                                    CodeAddressServiceStringAlloc,
-                                    CodeAddressServiceLock>
-    WalkTheStackCodeAddressService;
-
-mozilla::StaticAutoPtr<WalkTheStackCodeAddressService> gCodeAddressService;
+mozilla::StaticAutoPtr<CodeAddressService<>> gCodeAddressService;
 
 ////////////////////////////////////////////////////////////////////////////////
 
@@ -799,7 +763,7 @@ void nsTraceRefcnt::WalkTheStack(void (*aWriter)(uint32_t, void*, void*,
  */
 static void WalkTheStackCached(FILE* aStream) {
   if (!gCodeAddressService) {
-    gCodeAddressService = new WalkTheStackCodeAddressService();
+    gCodeAddressService = new CodeAddressService<>();
   }
   MozStackWalk(PrintStackFrameCached, /* skipFrames */ 2, /* maxFrames */ 0,
                aStream);
@@ -807,7 +771,7 @@ static void WalkTheStackCached(FILE* aStream) {
 
 static void WalkTheStackSavingLocations(std::vector<void*>& aLocations) {
   if (!gCodeAddressService) {
-    gCodeAddressService = new WalkTheStackCodeAddressService();
+    gCodeAddressService = new CodeAddressService<>();
   }
   static const int kFramesToSkip = 0 +  // this frame gets inlined
                                    1 +  // GetSerialNumber
diff --git a/xpcom/base/nscore.h b/xpcom/base/nscore.h
index 23d1631394..f08fe35c2a 100644
--- a/xpcom/base/nscore.h
+++ b/xpcom/base/nscore.h
@@ -217,7 +217,19 @@ template <typename T>
 struct UnusedZero;
 template <>
 struct UnusedZero<nsresult> {
-  static const bool value = true;
+  using StorageType = nsresult;
+
+  static constexpr bool value = true;
+  static constexpr StorageType nullValue = NS_OK;
+
+  static constexpr StorageType GetDefaultValue() { return NS_ERROR_FAILURE; }
+
+  static constexpr void AssertValid(StorageType aValue) {}
+  static constexpr const nsresult& Inspect(const StorageType& aValue) {
+    return aValue;
+  }
+  static constexpr nsresult Unwrap(StorageType aValue) { return aValue; }
+  static constexpr StorageType Store(nsresult aValue) { return aValue; }
 };
 }  // namespace detail
 
diff --git a/xpcom/build/FileLocation.h b/xpcom/build/FileLocation.h
index 05149cce51..bbe63d5c04 100644
--- a/xpcom/build/FileLocation.h
+++ b/xpcom/build/FileLocation.h
@@ -7,7 +7,6 @@
 
 #include "nsString.h"
 #include "nsCOMPtr.h"
-#include "nsAutoPtr.h"
 #include "nsIFile.h"
 #include "FileUtils.h"
 
diff --git a/xpcom/build/GeckoProcessTypes.h b/xpcom/build/GeckoProcessTypes.h
index d684162a4d..ff3079d1e8 100644
--- a/xpcom/build/GeckoProcessTypes.h
+++ b/xpcom/build/GeckoProcessTypes.h
@@ -18,7 +18,8 @@
 // said values are exposed to things like telemetry as well, so please
 // do not reorder lines in this file.
 //
-// Please add new process types at the end of this list.
+// Please add new process types at the end of this list
+// and update widget/ProcInfo.h
 GECKO_PROCESS_TYPE(Default, "default", Parent, Self)
 GECKO_PROCESS_TYPE(Plugin, "plugin", Plugin, PluginContainer)
 GECKO_PROCESS_TYPE(Content, "tab", Content, Self)
diff --git a/xpcom/build/IOInterposer.h b/xpcom/build/IOInterposer.h
index 18fdc2548b..de2b7b2900 100644
--- a/xpcom/build/IOInterposer.h
+++ b/xpcom/build/IOInterposer.h
@@ -6,7 +6,6 @@
 #define mozilla_IOInterposer_h
 
 #include "mozilla/Attributes.h"
-#include "mozilla/GuardObjects.h"
 #include "mozilla/TimeStamp.h"
 #include "nsString.h"
 
@@ -268,14 +267,10 @@ class IOInterposerInit {
 
 class MOZ_RAII AutoIOInterposerDisable final {
  public:
-  explicit AutoIOInterposerDisable(MOZ_GUARD_OBJECT_NOTIFIER_ONLY_PARAM) {
-    MOZ_GUARD_OBJECT_NOTIFIER_INIT;
-    IOInterposer::Disable();
-  }
+  explicit AutoIOInterposerDisable() { IOInterposer::Disable(); }
   ~AutoIOInterposerDisable() { IOInterposer::Enable(); }
 
  private:
-  MOZ_DECL_USE_GUARD_OBJECT_NOTIFIER
 };
 
 }  // namespace mozilla
diff --git a/xpcom/build/LateWriteChecks.cpp b/xpcom/build/LateWriteChecks.cpp
index f12f7f7438..09a4a89d9a 100644
--- a/xpcom/build/LateWriteChecks.cpp
+++ b/xpcom/build/LateWriteChecks.cpp
@@ -4,8 +4,8 @@
 
 #include <algorithm>
 
-//#include "mozilla/IOInterposer.h"
-//#include "mozilla/PoisonIOInterposer.h"
+#include "mozilla/IOInterposer.h"
+#include "mozilla/PoisonIOInterposer.h"
 #include "mozilla/ProcessedStack.h"
 #include "mozilla/SHA1.h"
 #include "mozilla/Scoped.h"
@@ -227,7 +227,7 @@ void StopLateWriteChecks() {
     IOInterposer::Unregister(IOInterposeObserver::OpAll, sLateWriteObserver);
     // Deallocation would not be thread-safe, and StopLateWriteChecks() is
     // called at shutdown and only in special cases.
-    // sLateWriteObserver = nullptr;
+    sLateWriteObserver = nullptr;
   }
 }
 
diff --git a/xpcom/build/MainThreadIOLogger.cpp b/xpcom/build/MainThreadIOLogger.cpp
index 2bea5d4e53..fced3ccc75 100644
--- a/xpcom/build/MainThreadIOLogger.cpp
+++ b/xpcom/build/MainThreadIOLogger.cpp
@@ -9,7 +9,7 @@
 #include "mozilla/IOInterposer.h"
 #include "mozilla/StaticPtr.h"
 #include "mozilla/TimeStamp.h"
-#include "nsAutoPtr.h"
+#include "mozilla/UniquePtr.h"
 #include "nsNativeCharsetUtils.h"
 #include "nsThreadUtils.h"
 
@@ -207,11 +207,11 @@ namespace mozilla {
 namespace MainThreadIOLogger {
 
 bool Init() {
-  nsAutoPtr<MainThreadIOLoggerImpl> impl(new MainThreadIOLoggerImpl());
+  auto impl = MakeUnique<MainThreadIOLoggerImpl>();
   if (!impl->Init()) {
     return false;
   }
-  sImpl = impl.forget();
+  sImpl = impl.release();
   IOInterposer::Register(IOInterposeObserver::OpAllWithStaging, sImpl);
   return true;
 }
diff --git a/xpcom/build/XPCOMInit.cpp b/xpcom/build/XPCOMInit.cpp
index aafa741c15..03881662ee 100644
--- a/xpcom/build/XPCOMInit.cpp
+++ b/xpcom/build/XPCOMInit.cpp
@@ -21,6 +21,7 @@
 #include "nsXPCOMPrivate.h"
 #include "nsXPCOMCIDInternal.h"
 
+#include "mozilla/dom/JSExecutionManager.h"
 #include "mozilla/layers/ImageBridgeChild.h"
 #include "mozilla/layers/CompositorBridgeParent.h"
 
@@ -71,8 +72,8 @@
 #include "mozilla/Telemetry.h"
 #include "mozilla/BackgroundHangMonitor.h"
 
-//#include "mozilla/PoisonIOInterposer.h"
-//#include "mozilla/LateWriteChecks.h"
+#include "mozilla/PoisonIOInterposer.h"
+#include "mozilla/LateWriteChecks.h"
 
 #include "mozilla/scache/StartupCache.h"
 
@@ -321,6 +322,7 @@ NS_InitXPCOM(nsIServiceManager** aResult, nsIFile* aBinDirectory,
   if (NS_WARN_IF(NS_FAILED(rv))) {
     return rv;
   }
+  AUTO_PROFILER_INIT2;
 
   // Init the SystemGroup for dispatching main thread runnables.
   SystemGroup::InitStatic();
@@ -482,6 +484,8 @@ NS_InitXPCOM(nsIServiceManager** aResult, nsIFile* aBinDirectory,
       loop->thread_name().c_str(), loop->transient_hang_timeout(),
       loop->permanent_hang_timeout());
 
+  mozilla::dom::JSExecutionManager::Initialize();
+
   return NS_OK;
 }
 
@@ -648,6 +652,8 @@ nsresult ShutdownXPCOM(nsIServiceManager* aServMgr) {
 
     BackgroundHangMonitor().NotifyActivity();
 
+    mozilla::dom::JSExecutionManager::Shutdown();
+
     // Late-write checks needs to find the profile directory, so it has to
     // be initialized before mozilla::services::Shutdown or (because of
     // xpcshell tests replacing the service) modules being unloaded.
diff --git a/xpcom/build/components.conf b/xpcom/build/components.conf
index d9f1ea4444..d8eac48947 100644
--- a/xpcom/build/components.conf
+++ b/xpcom/build/components.conf
@@ -30,8 +30,10 @@ Classes = [
         'constructor': 'nsChromeRegistry::GetSingleton',
     },
     {
+        'js_name': 'console',
         'cid': '{7e3ff85c-1dd2-11b2-8d4b-eb452cb0ff40}',
         'contract_ids': ['@mozilla.org/consoleservice;1'],
+        'interfaces': ['nsIConsoleService'],
         'type': 'nsConsoleService',
         'headers': ['/xpcom/base/nsConsoleService.h'],
         'init_method': 'Init',
@@ -182,15 +184,20 @@ Classes = [
         'headers': ['nsSupportsPrimitives.h'],
     },
     {
+        'js_name': 'sysinfo',
         'cid': '{d962398a-99e5-49b2-857a-c159049c7f6c}',
         'contract_ids': ['@mozilla.org/system-info;1'],
+        'interfaces': ['nsIPropertyBag2'],
         'type': 'nsSystemInfo',
         'headers': ['nsSystemInfo.h'],
         'init_method': 'Init',
+        'overridable': True,
     },
     {
+        'js_name': 'tm',
         'cid': '{7a4204c6-e45a-4c37-8ebb-6709a22c917c}',
         'contract_ids': ['@mozilla.org/thread-manager;1'],
+        'interfaces': ['nsIThreadManager'],
         'legacy_constructor': 'nsThreadManagerGetSingleton',
         'headers': ['/xpcom/build/XPCOMModule.h'],
     },
@@ -208,8 +215,10 @@ Classes = [
         'headers': ['nsVariant.h'],
     },
     {
+        'js_name': 'vc',
         'cid': '{c6e47036-ca94-4be3-963a-9abd8705f7a8}',
         'contract_ids': ['@mozilla.org/xpcom/version-comparator;1'],
+        'interfaces': ['nsIVersionComparator'],
         'type': 'nsVersionComparatorImpl',
         'headers': ['/xpcom/base/nsVersionComparatorImpl.h'],
     },
diff --git a/xpcom/build/moz.build b/xpcom/build/moz.build
index 1c3cd28a24..f0ee8c77d9 100644
--- a/xpcom/build/moz.build
+++ b/xpcom/build/moz.build
@@ -16,11 +16,36 @@ EXPORTS.mozilla += [
     '!Services.h',
     'FileLocation.h',
     'GeckoProcessTypes.h',
+    'IOInterposer.h',
+    'LateWriteChecks.h',
     'Omnijar.h',
+    'PoisonIOInterposer.h',
     'XPCOM.h',
     'XREAppData.h',
 ]
 
+if CONFIG['OS_ARCH'] == 'WINNT':
+    EXPORTS.mozilla += [
+        'perfprobe.h',
+    ]
+    SOURCES += ['perfprobe.cpp']
+    if CONFIG['CC_TYPE'] not in ('gcc', 'clang'):
+        SOURCES += [
+            'PoisonIOInterposerBase.cpp',
+            'PoisonIOInterposerWin.cpp',
+        ]
+    else:
+        SOURCES += ['PoisonIOInterposerStub.cpp']
+elif CONFIG['MOZ_WIDGET_TOOLKIT'] == 'cocoa':
+    UNIFIED_SOURCES += [
+        'PoisonIOInterposerBase.cpp',
+        'PoisonIOInterposerMac.cpp',
+    ]
+    SOURCES += ['mach_override.c']
+    SOURCES['mach_override.c'].flags += ['-Wno-unused-function']
+else:
+    SOURCES += ['PoisonIOInterposerStub.cpp']
+
 include('../glue/objs.mozbuild')
 
 XPCOM_MANIFESTS += [
@@ -32,7 +57,8 @@ UNIFIED_SOURCES += xpcom_glue_src_cppsrcs
 
 UNIFIED_SOURCES += [
     'FileLocation.cpp',
-#    'MainThreadIOLogger.cpp',
+    'IOInterposer.cpp',
+    'MainThreadIOLogger.cpp',
     'Omnijar.cpp',
     'XPCOMInit.cpp',
 ]
@@ -41,7 +67,7 @@ SOURCES += ['!Services.cpp']
 
 if CONFIG['OS_ARCH'] != 'WINNT':
     SOURCES += [
-#        'NSPRInterposer.cpp',
+        'NSPRInterposer.cpp',
     ]
 
 GeneratedFile('Services.cpp', script='Services.py', entry_point='services_cpp')
diff --git a/xpcom/build/perfprobe.cpp b/xpcom/build/perfprobe.cpp
index 5a3154e17a..ac7f6cf1bc 100644
--- a/xpcom/build/perfprobe.cpp
+++ b/xpcom/build/perfprobe.cpp
@@ -10,7 +10,6 @@
 #include <evntrace.h>
 
 #include "perfprobe.h"
-#include "nsAutoPtr.h"
 
 namespace mozilla {
 namespace probes {
diff --git a/xpcom/build/perfprobe.h b/xpcom/build/perfprobe.h
index 2ebc6875a0..2730f2f1f5 100644
--- a/xpcom/build/perfprobe.h
+++ b/xpcom/build/perfprobe.h
@@ -18,7 +18,6 @@
 #include "nsString.h"
 #include "mozilla/Logging.h"
 #include "nsTArray.h"
-#include "nsAutoPtr.h"
 #include <windows.h>
 #undef GetStartupInfo  // Prevent Windows from polluting global namespace
 #include <wmistr.h>
diff --git a/xpcom/components/StaticComponents.cpp.in b/xpcom/components/StaticComponents.cpp.in
index 8bc79b6700..7d65876f68 100644
--- a/xpcom/components/StaticComponents.cpp.in
+++ b/xpcom/components/StaticComponents.cpp.in
@@ -4,6 +4,7 @@
 
 #include "StaticComponents.h"
 
+#include "mozilla/ArrayUtils.h"
 #include "mozilla/PerfectHash.h"
 #include "mozilla/ResultExtensions.h"
 #include "mozilla/StaticPtr.h"
@@ -18,6 +19,8 @@
 #include "nsIXPConnect.h"
 #include "nsString.h"
 #include "nsStringEnumerator.h"
+#include "nsTArray.h"
+#include "xptinfo.h"
 
 // Cleanup pollution from zipstruct.h
 #undef UNSUPPORTED
@@ -69,6 +72,10 @@ const StaticCategoryEntry gStaticCategoryEntries[] = {
 //# @category_entries@
 };
 
+const nsXPTInterface gInterfaces[] = {
+//# @interfaces@
+};
+
 const StringOffset gComponentJSMs[] = {
 //# @component_jsms@
 };
@@ -129,6 +136,8 @@ static nsresult ConstructJSMComponent(const nsACString& aURI,
 
 //# @module_contract_id_table@
 
+//# @js_services_table@
+
 static inline bool CalledInit(size_t aIdx) {
   return GetBit(gInitCalled, aIdx);
 }
@@ -223,6 +232,14 @@ nsresult StaticModule::CreateInstance(nsISupports* aOuter, const nsIID& aIID,
   return CreateInstanceImpl(ID(), aOuter, aIID, aResult);
 }
 
+GetServiceHelper StaticModule::GetService() const {
+  return { ID(), nullptr };
+}
+
+GetServiceHelper StaticModule::GetService(nsresult* aRv) const {
+  return { ID(), aRv };
+}
+
 
 nsISupports* StaticModule::ServiceInstance() const {
   return gServiceInstances[Idx()];
@@ -248,6 +265,26 @@ nsCString StaticCategory::Name() const {
   return GetString(mName);
 }
 
+nsCString JSServiceEntry::Name() const {
+  return GetString(mName);
+}
+
+JSServiceEntry::InterfaceList JSServiceEntry::Interfaces() const {
+  InterfaceList iids;
+  iids.SetCapacity(mInterfaceCount);
+
+  for (size_t i = 0; i < mInterfaceCount; i++) {
+    nsXPTInterface ifaceID = gInterfaces[mInterfaceOffset.mOffset + i];
+    iids.AppendElement(&nsXPTInterfaceInfo::Get(ifaceID)->IID());
+  }
+  return iids;
+}
+
+
+/* static */
+const JSServiceEntry* JSServiceEntry::Lookup(const nsACString& aName) {
+  return LookupJSService(aName);
+}
 
 /* static */ const StaticModule* StaticComponents::LookupByCID(
     const nsID& aCID) {
@@ -287,6 +324,10 @@ StaticComponents::GetComponentJSMs() {
   return result.forget();
 }
 
+/* static */ Span<const JSServiceEntry> StaticComponents::GetJSServices() {
+  return { gJSServices, ArrayLength(gJSServices) };
+}
+
 /* static */ void StaticComponents::Shutdown() {
   CallUnloadFuncs();
 }
diff --git a/xpcom/components/StaticComponents.h b/xpcom/components/StaticComponents.h
index d6522ae695..112fe0edc8 100644
--- a/xpcom/components/StaticComponents.h
+++ b/xpcom/components/StaticComponents.h
@@ -7,6 +7,7 @@
 
 #include "mozilla/AlreadyAddRefed.h"
 #include "mozilla/Module.h"
+#include "mozilla/Span.h"
 #include "nsID.h"
 #include "nsStringFwd.h"
 #include "nscore.h"
@@ -17,6 +18,8 @@
 class nsIFactory;
 class nsIUTF8StringEnumerator;
 class nsISupports;
+template <typename T, size_t N>
+class AutoTArray;
 
 namespace mozilla {
 namespace xpcom {
@@ -70,6 +73,13 @@ struct StringOffset final {
   uint32_t mOffset;
 };
 
+/**
+ * Represents an offset into the interfaces table.
+ */
+struct InterfaceOffset final {
+  uint32_t mOffset;
+};
+
 /**
  * Represents a static component entry defined in a `Classes` list in an XPCOM
  * manifest. Handles creating instances of and caching service instances for
@@ -116,6 +126,9 @@ struct StaticModule {
   nsresult CreateInstance(nsISupports* aOuter, const nsIID& aIID,
                           void** aResult) const;
 
+  GetServiceHelper GetService() const;
+  GetServiceHelper GetService(nsresult*) const;
+
   nsISupports* ServiceInstance() const;
   void SetServiceInstance(already_AddRefed<nsISupports> aInst) const;
 };
@@ -194,6 +207,26 @@ struct StaticCategory final {
   }
 };
 
+struct JSServiceEntry final {
+  using InterfaceList = AutoTArray<const nsIID*, 4>;
+
+  static const JSServiceEntry* Lookup(const nsACString& aName);
+
+  StringOffset mName;
+  ModuleID mModuleID;
+
+  InterfaceOffset mInterfaceOffset;
+  uint8_t mInterfaceCount;
+
+  nsCString Name() const;
+
+  const StaticModule& Module() const {
+    return gStaticModules[size_t(mModuleID)];
+  }
+
+  InterfaceList Interfaces() const;
+};
+
 class StaticComponents final {
  public:
   static const StaticModule* LookupByCID(const nsID& aCID);
@@ -209,6 +242,8 @@ class StaticComponents final {
 
   static already_AddRefed<nsIUTF8StringEnumerator> GetComponentJSMs();
 
+  static Span<const JSServiceEntry> GetJSServices();
+
   /**
    * Calls any module unload from manifests whose components have been loaded.
    */
diff --git a/xpcom/components/components.conf b/xpcom/components/components.conf
index 10a0ba3978..5a2f7f5d3d 100644
--- a/xpcom/components/components.conf
+++ b/xpcom/components/components.conf
@@ -4,8 +4,10 @@
 
 Classes = [
     {
+        'js_name': 'catMan',
         'cid': '{16d222a6-1dd2-11b2-b693-f38b02c021b2}',
         'contract_ids': ['@mozilla.org/categorymanager;1'],
+        'interfaces': ['nsICategoryManager'],
         'legacy_constructor': 'nsCategoryManager::Create',
         'headers': ['/xpcom/components/nsCategoryManager.h'],
         'processes': ProcessSelector.ALLOW_IN_GPU_RDD_AND_SOCKET_PROCESS,
diff --git a/xpcom/components/gen_static_components.py b/xpcom/components/gen_static_components.py
index 9c45fbaf40..5ec12cf893 100644
--- a/xpcom/components/gen_static_components.py
+++ b/xpcom/components/gen_static_components.py
@@ -173,6 +173,8 @@ class StringTable(object):
 
 strings = StringTable()
 
+interfaces = []
+
 
 # Represents a C++ namespace, containing a set of classes and potentially
 # sub-namespaces. This is used to generate pre-declarations for incomplete
@@ -223,6 +225,17 @@ class ModuleEntry(object):
         self.processes = data.get('processes', 0)
         self.headers = data.get('headers', [])
 
+        self.js_name = data.get('js_name', None)
+        self.interfaces = data.get('interfaces', [])
+
+        if len(self.interfaces) > 255:
+            raise Exception('JS service %s may not have more than 255 '
+                            'interfaces' % self.js_name)
+
+        self.interfaces_offset = len(interfaces)
+        for iface in self.interfaces:
+            interfaces.append(iface)
+
         # If the manifest declares Init or Unload functions, this contains its
         # index, as understood by the `CallInitFunc()` function.
         #
@@ -304,6 +317,19 @@ class ModuleEntry(object):
                      contract_id=contract_id,
                      processes=lower_processes(self.processes))
 
+    # Generates the C++ code for a JSServiceEntry represengin this module.
+    def lower_js_service(self):
+        return """
+        {{
+          {js_name},
+          ModuleID::{name},
+          {{ {iface_offset} }},
+          {iface_count}
+        }}""".format(js_name=strings.entry_to_cxx(self.js_name),
+                     name=self.name,
+                     iface_offset=self.interfaces_offset,
+                     iface_count=len(self.interfaces))
+
     # Generates the C++ code necessary to construct an instance of this
     # component.
     #
@@ -495,6 +521,13 @@ def gen_module_funcs(substs, funcs):
     substs['init_count'] = len(funcs)
 
 
+def gen_interfaces(ifaces):
+    res = []
+    for iface in ifaces:
+        res.append('  nsXPTInterface::%s,\n' % iface)
+    return ''.join(res)
+
+
 # Generates class pre-declarations for any types referenced in `Classes` array
 # entries which do not have corresponding `headers` entries to fully declare
 # their types.
@@ -586,6 +619,7 @@ def gen_substs(manifests):
     contracts = []
     contract_map = {}
     categories = defaultdict(list)
+    js_services = {}
 
     jsms = set()
 
@@ -613,12 +647,20 @@ def gen_substs(manifests):
         if mod.jsm:
             jsms.add(mod.jsm)
 
+        if mod.js_name:
+            if mod.js_name in js_services:
+                raise Exception('Duplicate JS service name: %s' % mod.js_name)
+            js_services[mod.js_name] = mod
+
     cid_phf = PerfectHash(modules, PHF_SIZE,
                           key=lambda module: module.cid.bytes)
 
     contract_phf = PerfectHash(contracts, PHF_SIZE,
                                key=lambda entry: entry.contract)
 
+    js_services_phf = PerfectHash(list(js_services.values()), PHF_SIZE,
+                                  key=lambda entry: entry.js_name)
+
     substs = {}
 
     gen_categories(substs, categories)
@@ -636,6 +678,8 @@ def gen_substs(manifests):
     substs['component_jsms'] = '\n'.join(' %s,' % strings.entry_to_cxx(jsm)
                                          for jsm in sorted(jsms)) + '\n'
 
+    substs['interfaces'] = gen_interfaces(interfaces)
+
     substs['decls'] = gen_decls(types)
 
     substs['constructors'] = gen_constructors(cid_phf.entries)
@@ -669,6 +713,19 @@ def gen_substs(manifests):
         key_bytes='aKey.BeginReading()',
         key_length='aKey.Length()')
 
+    substs['js_services_table'] = js_services_phf.cxx_codegen(
+        name='LookupJSService',
+        entry_type='JSServiceEntry',
+        entries_name='gJSServices',
+        lower_entry=lambda entry: entry.lower_js_service(),
+
+        return_type='const JSServiceEntry*',
+        return_entry='return entry.Name() == aKey ? &entry : nullptr;',
+
+        key_type='const nsACString&',
+        key_bytes='aKey.BeginReading()',
+        key_length='aKey.Length()')
+
     # Do this only after everything else has been emitted so we're sure the
     # string table is complete.
     substs['strings'] = strings.to_cxx()
diff --git a/xpcom/components/nsCategoryCache.h b/xpcom/components/nsCategoryCache.h
index 0d8e715c6f..3068e81d29 100644
--- a/xpcom/components/nsCategoryCache.h
+++ b/xpcom/components/nsCategoryCache.h
@@ -11,7 +11,6 @@
 
 #include "nsServiceManagerUtils.h"
 
-#include "nsAutoPtr.h"
 #include "nsCOMArray.h"
 #include "nsInterfaceHashtable.h"
 
diff --git a/xpcom/components/nsComponentManager.cpp b/xpcom/components/nsComponentManager.cpp
index b6b5c5d737..f632013ecf 100644
--- a/xpcom/components/nsComponentManager.cpp
+++ b/xpcom/components/nsComponentManager.cpp
@@ -1448,10 +1448,6 @@ nsresult nsComponentManagerImpl::GetService(ModuleID aId, const nsIID& aIID,
 
   MutexLock lock(mLock);
 
-  if (!entry.Active()) {
-    return NS_ERROR_FACTORY_NOT_REGISTERED;
-  }
-
   Maybe<EntryWrapper> wrapper;
   if (entry.Overridable()) {
     // If we expect this service to be overridden by test code, we need to look
@@ -1460,6 +1456,8 @@ nsresult nsComponentManagerImpl::GetService(ModuleID aId, const nsIID& aIID,
     if (!wrapper) {
       return NS_ERROR_FACTORY_NOT_REGISTERED;
     }
+  } else if (!entry.Active()) {
+    return NS_ERROR_FACTORY_NOT_REGISTERED;
   } else {
     wrapper.emplace(&entry);
   }
@@ -1596,7 +1594,7 @@ nsComponentManagerImpl::RegisterFactory(const nsCID& aClass, const char* aName,
     return NS_ERROR_FACTORY_NOT_REGISTERED;
   }
 
-  nsAutoPtr<nsFactoryEntry> f(new nsFactoryEntry(aClass, aFactory));
+  auto f = MakeUnique<nsFactoryEntry>(aClass, aFactory);
 
   SafeMutexAutoLock lock(mLock);
   if (auto entry = mFactories.LookupForAdd(f->mCIDEntry->cid)) {
@@ -1608,12 +1606,12 @@ nsComponentManagerImpl::RegisterFactory(const nsCID& aClass, const char* aName,
     }
     if (aContractID) {
       nsDependentCString contractID(aContractID);
-      mContractIDs.Put(contractID, f);
+      mContractIDs.Put(contractID, f.get());
       // We allow dynamically-registered contract IDs to override static
       // entries, so invalidate any static entry for this contract ID.
       StaticComponents::InvalidateContractID(contractID);
     }
-    entry.OrInsert([&f]() { return f.forget(); });
+    entry.OrInsert([&f]() { return f.release(); });
   }
 
   return NS_OK;
diff --git a/xpcom/components/nsComponentManager.h b/xpcom/components/nsComponentManager.h
index fff10e068d..77c5699f36 100644
--- a/xpcom/components/nsComponentManager.h
+++ b/xpcom/components/nsComponentManager.h
@@ -18,6 +18,7 @@
 #include "mozilla/MemoryReporting.h"
 #include "mozilla/Module.h"
 #include "mozilla/Mutex.h"
+#include "mozilla/UniquePtr.h"
 #include "nsXULAppAPI.h"
 #include "nsIFactory.h"
 #include "nsIInterfaceRequestor.h"
@@ -25,7 +26,6 @@
 #include "PLDHashTable.h"
 #include "prtime.h"
 #include "nsCOMPtr.h"
-#include "nsAutoPtr.h"
 #include "nsWeakReference.h"
 #include "nsCOMArray.h"
 #include "nsDataHashtable.h"
@@ -220,7 +220,7 @@ class nsComponentManagerImpl final : public nsIComponentManager,
 
   // The KnownModule is kept alive by these members, it is
   // referenced by pointer from the factory entries.
-  nsTArray<nsAutoPtr<KnownModule>> mKnownStaticModules;
+  nsTArray<mozilla::UniquePtr<KnownModule>> mKnownStaticModules;
   // The key is the URI string of the module
   nsClassHashtable<nsCStringHashKey, KnownModule> mKnownModules;
 
diff --git a/xpcom/ds/ArrayAlgorithm.h b/xpcom/ds/ArrayAlgorithm.h
new file mode 100644
index 0000000000..1e193d4c2a
--- /dev/null
+++ b/xpcom/ds/ArrayAlgorithm.h
@@ -0,0 +1,107 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef ArrayAlgorithm_h___
+#define ArrayAlgorithm_h___
+
+#include "nsTArray.h"
+
+#include "mozilla/Algorithm.h"
+#include "mozilla/ResultExtensions.h"
+
+namespace mozilla {
+
+// An algorithm similar to TransformAbortOnErr, which creates a new nsTArray
+// rather than inserting into an output iterator. The capacity of the result
+// array is set to the number of elements that will be inserted if all
+// transformations are successful. This variant is fallible, i.e. if setting the
+// capacity fails, NS_ERROR_OUT_OF_MEMORY is returned as an error value. This
+// variant only works with nsresult errors.
+template <
+    typename SrcIter, typename Transform,
+    typename = std::enable_if_t<std::is_same_v<
+        typename detail::TransformTraits<Transform, SrcIter>::result_err_type,
+        nsresult>>>
+Result<nsTArray<typename detail::TransformTraits<Transform,
+                                                 SrcIter>::result_ok_type>,
+       nsresult>
+TransformIntoNewArrayAbortOnErr(SrcIter aIter, SrcIter aEnd,
+                                Transform aTransform, fallible_t) {
+  nsTArray<typename detail::TransformTraits<Transform, SrcIter>::result_ok_type>
+      res;
+  if (!res.SetCapacity(std::distance(aIter, aEnd), fallible)) {
+    return Err(NS_ERROR_OUT_OF_MEMORY);
+  }
+
+  auto transformRes = TransformAbortOnErr(aIter, aEnd, MakeBackInserter(res),
+                                          std::move(aTransform));
+  if (NS_WARN_IF(transformRes.isErr())) {
+    return Err(transformRes.unwrapErr());
+  }
+
+  return res;
+}
+
+template <typename SrcRange, typename Transform>
+auto TransformIntoNewArrayAbortOnErr(SrcRange& aRange, Transform aTransform,
+                                     fallible_t) {
+  using std::begin;
+  using std::end;
+  return TransformIntoNewArrayAbortOnErr(begin(aRange), end(aRange), aTransform,
+                                         fallible);
+}
+
+// An algorithm similar to std::transform, which creates a new nsTArray
+// rather than inserting into an output iterator. The capacity of the result
+// array is set to the number of elements that will be inserted. This variant is
+// fallible, i.e. if setting the capacity fails, NS_ERROR_OUT_OF_MEMORY is
+// returned as an error value. This variant only works with nsresult errors.
+template <typename SrcIter, typename Transform>
+Result<nsTArray<detail::ArrayElementTransformType<Transform, SrcIter>>,
+       nsresult>
+TransformIntoNewArray(SrcIter aIter, SrcIter aEnd, Transform aTransform,
+                      fallible_t) {
+  nsTArray<detail::ArrayElementTransformType<Transform, SrcIter>> res;
+  if (!res.SetCapacity(std::distance(aIter, aEnd), fallible)) {
+    return Err(NS_ERROR_OUT_OF_MEMORY);
+  }
+
+  std::transform(aIter, aEnd, MakeBackInserter(res), std::move(aTransform));
+
+  return res;
+}
+
+template <typename SrcRange, typename Transform>
+auto TransformIntoNewArray(SrcRange& aRange, Transform aTransform, fallible_t) {
+  using std::begin;
+  using std::end;
+  return TransformIntoNewArray(begin(aRange), end(aRange), aTransform,
+                               fallible);
+}
+
+// An algorithm similar to std::transform, which creates a new nsTArray
+// rather than inserting into an output iterator. The capacity of the result
+// array is set to the number of elements that will be inserted. This variant is
+// infallible, i.e. if setting the capacity fails, the process is aborted.
+template <typename SrcIter, typename Transform>
+nsTArray<detail::ArrayElementTransformType<Transform, SrcIter>>
+TransformIntoNewArray(SrcIter aIter, SrcIter aEnd, Transform aTransform) {
+  nsTArray<detail::ArrayElementTransformType<Transform, SrcIter>> res;
+  res.SetCapacity(std::distance(aIter, aEnd));
+
+  std::transform(aIter, aEnd, MakeBackInserter(res), std::move(aTransform));
+
+  return res;
+}
+
+template <typename SrcRange, typename Transform>
+auto TransformIntoNewArray(SrcRange& aRange, Transform aTransform) {
+  using std::begin;
+  using std::end;
+  return TransformIntoNewArray(begin(aRange), end(aRange), aTransform);
+}
+
+}  // namespace mozilla
+
+#endif  // !defined(ArrayAlgorithm_h___)
diff --git a/xpcom/ds/StaticAtoms.py b/xpcom/ds/StaticAtoms.py
index 8b9faee7e2..805e451351 100644
--- a/xpcom/ds/StaticAtoms.py
+++ b/xpcom/ds/StaticAtoms.py
@@ -1636,6 +1636,7 @@ STATIC_ATOMS = [
     Atom("csch_", "csch"),
     Atom("cs_", "cs"),
     Atom("csymbol_", "csymbol"),
+    Atom("csp", "csp"),
     Atom("curl_", "curl"),
     Atom("decimalpoint_", "decimalpoint"),
     Atom("definitionURL_", "definitionURL"),
diff --git a/xpcom/ds/Tokenizer.h b/xpcom/ds/Tokenizer.h
index 439a85c46e..ab136220aa 100644
--- a/xpcom/ds/Tokenizer.h
+++ b/xpcom/ds/Tokenizer.h
@@ -383,9 +383,9 @@ class TTokenizer : public TokenizerBase<TChar> {
   /**
    * Same as above, but accepts an integer with an optional minus sign.
    */
-  template <typename T, typename V = typename EnableIf<
-                            std::is_signed_v<typename RemovePointer<T>::Type>,
-                            typename RemovePointer<T>::Type>::Type>
+  template <typename T, typename V = std::enable_if_t<
+                            std::is_signed_v<std::remove_pointer_t<T>>,
+                            std::remove_pointer_t<T>>>
   [[nodiscard]] bool ReadSignedInteger(T* aValue) {
     MOZ_RELEASE_ASSERT(aValue);
 
diff --git a/xpcom/ds/components.conf b/xpcom/ds/components.conf
index 1810ebc6df..a057800c56 100644
--- a/xpcom/ds/components.conf
+++ b/xpcom/ds/components.conf
@@ -10,8 +10,10 @@ Classes = [
         'headers': ['nsArray.h'],
     },
     {
+        'js_name': 'obs',
         'cid': '{d07f5195-e3d1-11d2-8acd-00105a1b8860}',
         'contract_ids': ['@mozilla.org/observer-service;1'],
+        'interfaces': ['nsIObserverService'],
         'legacy_constructor': 'nsObserverService::Create',
         'headers': ['/xpcom/ds/nsObserverService.h'],
         'processes': ProcessSelector.ALLOW_IN_GPU_RDD_VR_AND_SOCKET_PROCESS,
diff --git a/xpcom/ds/moz.build b/xpcom/ds/moz.build
index cb09364453..ac2a5ae083 100644
--- a/xpcom/ds/moz.build
+++ b/xpcom/ds/moz.build
@@ -86,6 +86,7 @@ EXPORTS += [
 EXPORTS.mozilla += [
     'ArenaAllocator.h',
     'ArenaAllocatorExtensions.h',
+    'ArrayAlgorithm.h',
     'ArrayIterator.h',
     'AtomArray.h',
     'Dafsa.h',
diff --git a/xpcom/ds/nsAtomTable.cpp b/xpcom/ds/nsAtomTable.cpp
index 089dfd3c53..b281571eea 100644
--- a/xpcom/ds/nsAtomTable.cpp
+++ b/xpcom/ds/nsAtomTable.cpp
@@ -15,7 +15,6 @@
 
 #include "nsAtom.h"
 #include "nsAtomTable.h"
-#include "nsAutoPtr.h"
 #include "nsCRT.h"
 #include "nsDataHashtable.h"
 #include "nsGkAtoms.h"
diff --git a/xpcom/ds/nsCOMArray.h b/xpcom/ds/nsCOMArray.h
index d06795bd59..5842f782d7 100644
--- a/xpcom/ds/nsCOMArray.h
+++ b/xpcom/ds/nsCOMArray.h
@@ -8,12 +8,13 @@
 #include "mozilla/Attributes.h"
 #include "mozilla/ArrayIterator.h"
 #include "mozilla/MemoryReporting.h"
-#include "mozilla/ReverseIterator.h"
 
 #include "nsCycleCollectionNoteChild.h"
 #include "nsTArray.h"
 #include "nsISupports.h"
 
+#include <iterator>
+
 // See below for the definition of nsCOMArray<T>
 
 // a class that's nsISupports-specific, so that we can contain the
@@ -205,8 +206,8 @@ class nsCOMArray : public nsCOMArray_base {
   typedef int32_t index_type;
   typedef mozilla::ArrayIterator<T*, nsCOMArray> iterator;
   typedef mozilla::ArrayIterator<const T*, nsCOMArray> const_iterator;
-  typedef mozilla::ReverseIterator<iterator> reverse_iterator;
-  typedef mozilla::ReverseIterator<const_iterator> const_reverse_iterator;
+  typedef std::reverse_iterator<iterator> reverse_iterator;
+  typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
 
   nsCOMArray() = default;
   explicit nsCOMArray(int32_t aCount) : nsCOMArray_base(aCount) {}
diff --git a/xpcom/ds/nsExpirationTracker.h b/xpcom/ds/nsExpirationTracker.h
index 0b44e84be6..84073949c9 100644
--- a/xpcom/ds/nsExpirationTracker.h
+++ b/xpcom/ds/nsExpirationTracker.h
@@ -9,7 +9,6 @@
 #include "nsTArray.h"
 #include "nsITimer.h"
 #include "nsCOMPtr.h"
-#include "nsAutoPtr.h"
 #include "nsComponentManagerUtils.h"
 #include "nsIEventTarget.h"
 #include "nsIObserver.h"
@@ -188,12 +187,13 @@ class ExpirationTrackerImpl {
     MOZ_ASSERT(generation.Length() > index && generation[index] == aObj,
                "Object is lying about its index");
     // Move the last object to fill the hole created by removing aObj
-    uint32_t last = generation.Length() - 1;
-    T* lastObj = generation[last];
-    generation[index] = lastObj;
+    T* lastObj = generation.PopLastElement();
+    // XXX It looks weird that index might point to the element that was just
+    // removed. Is that really correct?
+    if (index < generation.Length()) {
+      generation[index] = lastObj;
+    }
     lastObj->GetExpirationState()->mIndexInGeneration = index;
-    generation.RemoveElementAt(last);
-    MOZ_ASSERT(generation.Length() == last);
     state->mGeneration = nsExpirationState::NOT_TRACKED;
     // We do not check whether we need to stop the timer here. The timer
     // will check that itself next time it fires. Checking here would not
diff --git a/xpcom/ds/nsHashKeys.h b/xpcom/ds/nsHashKeys.h
index d1f46b68b6..dcf62fa809 100644
--- a/xpcom/ds/nsHashKeys.h
+++ b/xpcom/ds/nsHashKeys.h
@@ -7,7 +7,6 @@
 
 #include "nsID.h"
 #include "nsISupports.h"
-#include "nsAutoPtr.h"
 #include "nsCOMPtr.h"
 #include "PLDHashTable.h"
 #include <new>
diff --git a/xpcom/ds/nsObserverList.cpp b/xpcom/ds/nsObserverList.cpp
index a292d523eb..fd4c537aa1 100644
--- a/xpcom/ds/nsObserverList.cpp
+++ b/xpcom/ds/nsObserverList.cpp
@@ -5,7 +5,6 @@
 #include "nsObserverList.h"
 
 #include "mozilla/ResultExtensions.h"
-#include "nsAutoPtr.h"
 #include "nsCOMArray.h"
 #include "xpcpublic.h"
 
diff --git a/xpcom/ds/nsObserverService.cpp b/xpcom/ds/nsObserverService.cpp
index c943b76a4e..a2851738ca 100644
--- a/xpcom/ds/nsObserverService.cpp
+++ b/xpcom/ds/nsObserverService.cpp
@@ -3,7 +3,6 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #include "mozilla/Logging.h"
-#include "nsAutoPtr.h"
 #include "nsComponentManagerUtils.h"
 #include "nsIConsoleService.h"
 #include "nsIObserverService.h"
diff --git a/xpcom/ds/nsPersistentProperties.cpp b/xpcom/ds/nsPersistentProperties.cpp
index 410806b8a9..52d69e8cc4 100644
--- a/xpcom/ds/nsPersistentProperties.cpp
+++ b/xpcom/ds/nsPersistentProperties.cpp
@@ -7,7 +7,6 @@
 #include "nsCOMArray.h"
 #include "nsUnicharInputStream.h"
 #include "nsPrintfCString.h"
-#include "nsAutoPtr.h"
 
 #include "nsPersistentProperties.h"
 #include "nsIProperties.h"
diff --git a/xpcom/ds/nsRefPtrHashtable.h b/xpcom/ds/nsRefPtrHashtable.h
index c00303b0b3..9a947cc51b 100644
--- a/xpcom/ds/nsRefPtrHashtable.h
+++ b/xpcom/ds/nsRefPtrHashtable.h
@@ -7,7 +7,6 @@
 
 #include "nsBaseHashtable.h"
 #include "nsHashKeys.h"
-#include "nsAutoPtr.h"
 
 /**
  * templated hashtable class maps keys to reference pointers.
diff --git a/xpcom/ds/nsTArray.h b/xpcom/ds/nsTArray.h
index b0a5598154..a9c508d3ed 100644
--- a/xpcom/ds/nsTArray.h
+++ b/xpcom/ds/nsTArray.h
@@ -9,6 +9,7 @@
 
 #include <functional>
 #include <initializer_list>
+#include <iterator>
 #include <new>
 #include <ostream>
 #include <type_traits>
@@ -25,7 +26,6 @@
 #include "mozilla/MathAlgorithms.h"
 #include "mozilla/MemoryReporting.h"
 #include "mozilla/NotNull.h"
-#include "mozilla/ReverseIterator.h"
 #include "mozilla/Span.h"
 #include "mozilla/TypeTraits.h"
 #include "mozilla/fallible.h"
@@ -912,8 +912,8 @@ class nsTArray_Impl
       safeelementat_helper_type;
   typedef mozilla::ArrayIterator<elem_type&, nsTArray<E>> iterator;
   typedef mozilla::ArrayIterator<const elem_type&, nsTArray<E>> const_iterator;
-  typedef mozilla::ReverseIterator<iterator> reverse_iterator;
-  typedef mozilla::ReverseIterator<const_iterator> const_reverse_iterator;
+  typedef std::reverse_iterator<iterator> reverse_iterator;
+  typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
 
   using base_type::EmptyHdr;
   using safeelementat_helper_type::SafeElementAt;
diff --git a/xpcom/ds/nsTObserverArray.h b/xpcom/ds/nsTObserverArray.h
index 17eb580e80..17c9f752ab 100644
--- a/xpcom/ds/nsTObserverArray.h
+++ b/xpcom/ds/nsTObserverArray.h
@@ -6,6 +6,7 @@
 #define nsTObserverArray_h___
 
 #include "mozilla/MemoryReporting.h"
+#include "mozilla/ReverseIterator.h"
 #include "nsTArray.h"
 #include "nsCycleCollectionNoteChild.h"
 
@@ -29,6 +30,9 @@ class nsTObserverArray_base {
 
  protected:
   class Iterator_base {
+   public:
+    Iterator_base(const Iterator_base&) = delete;
+
    protected:
     friend class nsTObserverArray_base;
 
@@ -181,8 +185,8 @@ class nsAutoTObserverArray : protected nsTObserverArray_base {
   // Append an element to the array.
   // @param aItem The item to append.
   template <class Item>
-  void AppendElement(const Item& aItem) {
-    mArray.AppendElement(aItem);
+  void AppendElement(Item&& aItem) {
+    mArray.AppendElement(std::forward<Item>(aItem));
   }
 
   // Same as above, but without copy-constructing. This is useful to avoid
@@ -268,6 +272,9 @@ class nsAutoTObserverArray : protected nsTObserverArray_base {
     friend class nsAutoTObserverArray;
     typedef nsAutoTObserverArray<T, N> array_type;
 
+    Iterator(const Iterator& aOther)
+        : Iterator(aOther.mPosition, aOther.mArray) {}
+
     Iterator(index_type aPosition, const array_type& aArray)
         : Iterator_base(aPosition, aArray.mIterators),
           mArray(const_cast<array_type&>(aArray)) {
@@ -388,6 +395,110 @@ class nsAutoTObserverArray : protected nsTObserverArray_base {
     }
   };
 
+  struct EndSentinel {};
+
+  // Internal type, do not use directly, see
+  // ForwardRange()/EndLimitedRange()/BackwardRange().
+  template <typename Iterator, typename U>
+  struct STLIterator {
+    using value_type = std::remove_reference_t<U>;
+
+    explicit STLIterator(const nsAutoTObserverArray<T, N>& aArray)
+        : mIterator{aArray} {
+      operator++();
+    }
+
+    bool operator!=(const EndSentinel&) const {
+      // We are a non-end-sentinel and the other is an end-sentinel, so we are
+      // still valid if mCurrent is valid.
+      return mCurrent;
+    }
+
+    STLIterator& operator++() {
+      mCurrent = mIterator.HasMore() ? &mIterator.GetNext() : nullptr;
+      return *this;
+    }
+
+    value_type* operator->() { return mCurrent; }
+    U& operator*() { return *mCurrent; }
+
+   private:
+    Iterator mIterator;
+    value_type* mCurrent;
+  };
+
+  // Internal type, do not use directly, see
+  // ForwardRange()/EndLimitedRange()/BackwardRange().
+  template <typename Iterator, typename U>
+  class STLIteratorRange {
+   public:
+    using iterator = STLIterator<Iterator, U>;
+
+    explicit STLIteratorRange(const nsAutoTObserverArray<T, N>& aArray)
+        : mArray{aArray} {}
+
+    STLIteratorRange(const STLIteratorRange& aOther) = delete;
+
+    iterator begin() const { return iterator{mArray}; }
+    EndSentinel end() const { return {}; }
+
+   private:
+    const nsAutoTObserverArray<T, N>& mArray;
+  };
+
+  template <typename U>
+  using STLForwardIteratorRange = STLIteratorRange<ForwardIterator, U>;
+
+  template <typename U>
+  using STLEndLimitedIteratorRange = STLIteratorRange<EndLimitedIterator, U>;
+
+  template <typename U>
+  using STLBackwardIteratorRange = STLIteratorRange<BackwardIterator, U>;
+
+  // Constructs a range (usable with range-based for) based on the
+  // ForwardIterator semantics. Note that this range does not provide
+  // full-feature STL-style iterators usable with STL-style algorithms.
+  auto ForwardRange() { return STLForwardIteratorRange<T>{*this}; }
+
+  // Constructs a const range (usable with range-based for) based on the
+  // ForwardIterator semantics. Note that this range does not provide
+  // full-feature STL-style iterators usable with STL-style algorithms.
+  auto ForwardRange() const { return STLForwardIteratorRange<const T>{*this}; }
+
+  // Constructs a range (usable with range-based for) based on the
+  // EndLimitedIterator semantics. Note that this range does not provide
+  // full-feature STL-style iterators usable with STL-style algorithms.
+  auto EndLimitedRange() { return STLEndLimitedIteratorRange<T>{*this}; }
+
+  // Constructs a const range (usable with range-based for) based on the
+  // EndLimitedIterator semantics. Note that this range does not provide
+  // full-feature STL-style iterators usable with STL-style algorithms.
+  auto EndLimitedRange() const {
+    return STLEndLimitedIteratorRange<const T>{*this};
+  }
+
+  // Constructs a range (usable with range-based for) based on the
+  // BackwardIterator semantics. Note that this range does not provide
+  // full-feature STL-style iterators usable with STL-style algorithms.
+  auto BackwardRange() { return STLBackwardIteratorRange<T>{*this}; }
+
+  // Constructs a const range (usable with range-based for) based on the
+  // BackwardIterator semantics. Note that this range does not provide
+  // full-feature STL-style iterators usable with STL-style algorithms.
+  auto BackwardRange() const {
+    return STLBackwardIteratorRange<const T>{*this};
+  }
+
+  // Constructs a const range (usable with range-based for and STL-style
+  // algorithms) based on a non-observing iterator. The array must not be
+  // modified during iteration.
+  auto NonObservingRange() const {
+    return mozilla::detail::IteratorRange<
+        typename AutoTArray<T, N>::const_iterator,
+        typename AutoTArray<T, N>::const_reverse_iterator>{mArray.cbegin(),
+                                                           mArray.cend()};
+  }
+
  protected:
   AutoTArray<T, N> mArray;
 };
diff --git a/xpcom/ds/nsTPriorityQueue.h b/xpcom/ds/nsTPriorityQueue.h
index 7832e15caf..032b03c1bf 100644
--- a/xpcom/ds/nsTPriorityQueue.h
+++ b/xpcom/ds/nsTPriorityQueue.h
@@ -91,11 +91,15 @@ class nsTPriorityQueue {
    */
   T Pop() {
     MOZ_ASSERT(!mElements.IsEmpty(), "Empty queue");
-    T pop = mElements[0];
+    T pop = std::move(mElements[0]);
+
+    if (mElements.Length() == 1) {
+      mElements.Clear();
+      return pop;
+    }
 
     // Move last to front
-    mElements[0] = mElements[mElements.Length() - 1];
-    mElements.TruncateLength(mElements.Length() - 1);
+    mElements[0] = mElements.PopLastElement();
 
     // Sift down
     size_type i = 0;
diff --git a/xpcom/ds/nsWindowsRegKey.cpp b/xpcom/ds/nsWindowsRegKey.cpp
index 8065726638..d5fb716af7 100644
--- a/xpcom/ds/nsWindowsRegKey.cpp
+++ b/xpcom/ds/nsWindowsRegKey.cpp
@@ -9,7 +9,6 @@
 #include "nsString.h"
 #include "nsCOMPtr.h"
 #include "mozilla/Attributes.h"
-#include "nsAutoPtr.h"
 
 //-----------------------------------------------------------------------------
 
diff --git a/xpcom/ds/tools/perfecthash.py b/xpcom/ds/tools/perfecthash.py
index a88c590dbd..eefc3a5092 100644
--- a/xpcom/ds/tools/perfecthash.py
+++ b/xpcom/ds/tools/perfecthash.py
@@ -301,18 +301,18 @@ class CGHelper(object):
             {
               %(basis_table)s
 
-              size_t length = js::GetLinearStringLength(aKey);
+              size_t length = JS::GetLinearStringLength(aKey);
 
               JS::AutoCheckCannotGC nogc;
-              if (js::LinearStringHasLatin1Chars(aKey)) {
+              if (JS::LinearStringHasLatin1Chars(aKey)) {
                 auto& entry = mozilla::perfecthash::Lookup(
-                  js::GetLatin1LinearStringChars(nogc, aKey),
+                  JS::GetLatin1LinearStringChars(nogc, aKey),
                   length, BASES, %(entries_name)s);
 
                 %(return_entry)s
               } else {
                 auto& entry = mozilla::perfecthash::Lookup(
-                  js::GetTwoByteLinearStringChars(nogc, aKey),
+                  JS::GetTwoByteLinearStringChars(nogc, aKey),
                   length, BASES, %(entries_name)s);
 
                 %(return_entry)s
diff --git a/xpcom/io/FilePreferences.cpp b/xpcom/io/FilePreferences.cpp
index 852e8c9855..82b5c93073 100644
--- a/xpcom/io/FilePreferences.cpp
+++ b/xpcom/io/FilePreferences.cpp
@@ -8,6 +8,7 @@
 #include "mozilla/Preferences.h"
 #include "mozilla/StaticMutex.h"
 #include "mozilla/StaticPtr.h"
+#include "mozilla/TextUtils.h"
 #include "mozilla/Tokenizer.h"
 #include "nsAppDirectoryServiceDefs.h"
 #include "nsDirectoryServiceDefs.h"
@@ -30,6 +31,8 @@ static WinPaths& PathWhitelist() {
 }
 
 #ifdef XP_WIN
+const auto kDevicePathSpecifier = NS_LITERAL_STRING("\\\\?\\");
+
 typedef char16_t char_path_t;
 #else
 typedef char char_path_t;
@@ -217,6 +220,28 @@ class TNormalizer : public TTokenizer<TChar> {
   nsTArray<nsTDependentSubstring<TChar>> mStack;
 };
 
+#ifdef XP_WIN
+bool IsDOSDevicePathWithDrive(const nsAString& aFilePath) {
+  if (!StringBeginsWith(aFilePath, kDevicePathSpecifier)) {
+    return false;
+  }
+
+  const auto pathNoPrefix =
+      nsDependentSubstring(aFilePath, kDevicePathSpecifier.Length());
+
+  // After the device path specifier, the rest of file path can be:
+  // - starts with the volume or drive. e.g. \\?\C:\...
+  // - UNCs. e.g. \\?\UNC\Server\Share\Test\Foo.txt
+  // - device UNCs. e.g. \\?\server1\e:\utilities\\filecomparer\...
+  // The first case should not be blocked by IsBlockedUNCPath.
+  if (!StartsWithDiskDesignatorAndBackslash(pathNoPrefix)) {
+    return false;
+  }
+
+  return true;
+}
+#endif
+
 }  // namespace
 
 bool IsBlockedUNCPath(const nsAString& aFilePath) {
@@ -229,6 +254,15 @@ bool IsBlockedUNCPath(const nsAString& aFilePath) {
     return false;
   }
 
+#ifdef XP_WIN
+  // ToDo: We don't need to check this once we can check if there is a valid
+  // server or host name that is prefaced by "\\".
+  // https://docs.microsoft.com/en-us/dotnet/standard/io/file-path-formats
+  if (IsDOSDevicePathWithDrive(aFilePath)) {
+    return false;
+  }
+#endif
+
   nsAutoString normalized;
   if (!Normalizer(aFilePath, Normalizer::Token::Char('\\')).Get(normalized)) {
     // Broken paths are considered invalid and thus inaccessible
@@ -304,6 +338,18 @@ bool IsAllowedPath(const nsTSubstring<char_path_t>& aFilePath) {
   return true;
 }
 
+#ifdef XP_WIN
+bool StartsWithDiskDesignatorAndBackslash(const nsAString& aAbsolutePath) {
+  // aAbsolutePath can only be (in regular expression):
+  // UNC path: ^\\\\.*
+  // A single backslash: ^\\.*
+  // A disk designator with a backslash: ^[A-Za-z]:\\.*
+  return aAbsolutePath.Length() >= 3 && IsAsciiAlpha(aAbsolutePath.CharAt(0)) &&
+         aAbsolutePath.CharAt(1) == L':' &&
+         aAbsolutePath.CharAt(2) == kPathSeparator;
+}
+#endif
+
 void testing::SetBlockUNCPaths(bool aBlock) { sBlockUNCPaths = aBlock; }
 
 void testing::AddDirectoryToWhitelist(nsAString const& aPath) {
diff --git a/xpcom/io/FilePreferences.h b/xpcom/io/FilePreferences.h
index 262e1f160f..962b1c1b5a 100644
--- a/xpcom/io/FilePreferences.h
+++ b/xpcom/io/FilePreferences.h
@@ -17,6 +17,15 @@ bool IsAllowedPath(const nsAString& aFilePath);
 bool IsAllowedPath(const nsACString& aFilePath);
 #endif
 
+#ifdef XP_WIN
+bool StartsWithDiskDesignatorAndBackslash(const nsAString& aAbsolutePath);
+#endif
+
+extern const char kPathSeparator;
+#ifdef XP_WIN
+extern const nsLiteralString kDevicePathSpecifier;
+#endif
+
 namespace testing {
 
 void SetBlockUNCPaths(bool aBlock);
diff --git a/xpcom/io/SpecialSystemDirectory.cpp b/xpcom/io/SpecialSystemDirectory.cpp
index 645bdb383b..8b4d6bc46a 100644
--- a/xpcom/io/SpecialSystemDirectory.cpp
+++ b/xpcom/io/SpecialSystemDirectory.cpp
@@ -5,7 +5,6 @@
 #include "SpecialSystemDirectory.h"
 #include "nsString.h"
 #include "nsDependentString.h"
-#include "nsAutoPtr.h"
 
 #if defined(XP_WIN)
 
diff --git a/xpcom/io/components.conf b/xpcom/io/components.conf
index f66c0ab86a..ddeb08b665 100644
--- a/xpcom/io/components.conf
+++ b/xpcom/io/components.conf
@@ -4,8 +4,10 @@
 
 Classes = [
     {
+        'js_name': 'dirsvc',
         'cid': '{f00152d0-b40b-11d3-8c9c-000064657374}',
         'contract_ids': ['@mozilla.org/file/directory_service;1'],
+        'interfaces': ['nsIDirectoryService', 'nsIProperties'],
         'legacy_constructor': 'nsDirectoryService::Create',
         'headers': ['nsDirectoryService.h'],
     },
diff --git a/xpcom/io/nsAnonymousTemporaryFile.cpp b/xpcom/io/nsAnonymousTemporaryFile.cpp
index 81253cfd80..2108ea106c 100644
--- a/xpcom/io/nsAnonymousTemporaryFile.cpp
+++ b/xpcom/io/nsAnonymousTemporaryFile.cpp
@@ -19,7 +19,6 @@
 #  include "nsIIdleService.h"
 #  include "nsISimpleEnumerator.h"
 #  include "nsIFile.h"
-#  include "nsAutoPtr.h"
 #  include "nsITimer.h"
 #  include "nsCRT.h"
 
diff --git a/xpcom/io/nsDirectoryService.cpp b/xpcom/io/nsDirectoryService.cpp
index b7a89ed57c..f3ade99210 100644
--- a/xpcom/io/nsDirectoryService.cpp
+++ b/xpcom/io/nsDirectoryService.cpp
@@ -5,7 +5,6 @@
 #include "mozilla/ArrayUtils.h"
 
 #include "nsCOMPtr.h"
-#include "nsAutoPtr.h"
 #include "nsDirectoryService.h"
 #include "nsLocalFile.h"
 #include "nsDebug.h"
diff --git a/xpcom/io/nsILocalFileWin.idl b/xpcom/io/nsILocalFileWin.idl
index f3b3d78580..b77c9af9ba 100644
--- a/xpcom/io/nsILocalFileWin.idl
+++ b/xpcom/io/nsILocalFileWin.idl
@@ -72,12 +72,32 @@ interface nsILocalFileWin : nsIFile
      * fileAttributesWin
      *
      * Set or get windows specific file attributes.
-     * 
+     *
      * Throws NS_ERROR_FILE_INVALID_PATH for an invalid file.
      * Throws NS_ERROR_FAILURE if the set or get fails.
      */
     attribute unsigned long fileAttributesWin;
 
+    /**
+     * Setting this to true will prepend the prefix "\\?\" to all parsed file
+     * paths which match ^[A-Za-z]:\\.* (regex) syntax.
+     *
+     * There are two known issues (and potentially more) which can be resolved
+     * by the prefix:
+     * - In the Windows API, the maximum length for a path is MAX_PATH in
+     *   general. However, Windows API has many functions that also have Unicode
+     *   versions to permit an extended-length path for a maximum total path
+     *   length of 32,767 characters.
+     *
+     * - A path component which ends with a dot is not allowed for Windows
+     *   API.
+     *
+     * If either of these issues are expected to be common in your code, you
+     * should set this flag to true. (You should probably not have to set this
+     * flag to true.)
+     */
+    attribute boolean useDOSDevicePathSyntax;
+
     /**
      * Identical to nsIFile::openNSPRFileDesc except it also uses the
      * FILE_SHARE_DELETE flag.
diff --git a/xpcom/io/nsInputStreamTee.cpp b/xpcom/io/nsInputStreamTee.cpp
index 705c34ef08..8b970f4482 100644
--- a/xpcom/io/nsInputStreamTee.cpp
+++ b/xpcom/io/nsInputStreamTee.cpp
@@ -5,13 +5,13 @@
 #include <stdlib.h>
 #include "mozilla/Logging.h"
 
+#include "mozilla/Maybe.h"
 #include "mozilla/Mutex.h"
 #include "mozilla/Attributes.h"
 #include "nsIInputStreamTee.h"
 #include "nsIInputStream.h"
 #include "nsIOutputStream.h"
 #include "nsCOMPtr.h"
-#include "nsAutoPtr.h"
 #include "nsIEventTarget.h"
 #include "nsThreadUtils.h"
 
@@ -48,7 +48,7 @@ class nsInputStreamTee final : public nsIInputStreamTee {
   nsCOMPtr<nsIEventTarget> mEventTarget;
   nsWriteSegmentFun mWriter;  // for implementing ReadSegments
   void* mClosure;             // for implementing ReadSegments
-  nsAutoPtr<Mutex> mLock;     // synchronize access to mSinkIsValid
+  Maybe<Mutex> mLock;         // synchronize access to mSinkIsValid
   bool mSinkIsValid;          // False if TeeWriteEvent fails
 };
 
@@ -126,7 +126,7 @@ class nsInputStreamTeeWriteEvent : public Runnable {
 };
 
 nsInputStreamTee::nsInputStreamTee()
-    : mWriter(nullptr), mClosure(nullptr), mLock(nullptr), mSinkIsValid(true) {}
+    : mWriter(nullptr), mClosure(nullptr), mLock(), mSinkIsValid(true) {}
 
 bool nsInputStreamTee::SinkIsValid() {
   MutexAutoLock lock(*mLock);
@@ -286,7 +286,7 @@ nsInputStreamTee::SetEventTarget(nsIEventTarget* aEventTarget) {
   mEventTarget = aEventTarget;
   if (mEventTarget) {
     // Only need synchronization if this is an async tee
-    mLock = new Mutex("nsInputStreamTee.mLock");
+    mLock.emplace("nsInputStreamTee.mLock");
   }
   return NS_OK;
 }
diff --git a/xpcom/io/nsLocalFileWin.cpp b/xpcom/io/nsLocalFileWin.cpp
index 8166e2082b..1532c18832 100644
--- a/xpcom/io/nsLocalFileWin.cpp
+++ b/xpcom/io/nsLocalFileWin.cpp
@@ -9,7 +9,6 @@
 #include "mozilla/WindowsVersion.h"
 
 #include "nsCOMPtr.h"
-#include "nsAutoPtr.h"
 #include "nsMemory.h"
 #include "GeckoProfiler.h"
 
@@ -59,6 +58,8 @@
 #include "mozilla/WidgetUtils.h"
 
 using namespace mozilla;
+using mozilla::FilePreferences::kDevicePathSpecifier;
+using mozilla::FilePreferences::kPathSeparator;
 
 #define CHECK_mWorkingPath()                                     \
   do {                                                           \
@@ -78,6 +79,28 @@ using namespace mozilla;
 #  define DRIVE_REMOTE 4
 #endif
 
+namespace {
+
+nsresult NewLocalFile(const nsAString& aPath, bool aFollowLinks,
+                      bool aUseDOSDevicePathSyntax, nsIFile** aResult) {
+  RefPtr<nsLocalFile> file = new nsLocalFile();
+
+  file->SetFollowLinks(aFollowLinks);
+  file->SetUseDOSDevicePathSyntax(aUseDOSDevicePathSyntax);
+
+  if (!aPath.IsEmpty()) {
+    nsresult rv = file->InitWithPath(aPath);
+    if (NS_FAILED(rv)) {
+      return rv;
+    }
+  }
+
+  file.forget(aResult);
+  return NS_OK;
+}
+
+}  // anonymous namespace
+
 static HWND GetMostRecentNavigatorHWND() {
   nsresult rv;
   nsCOMPtr<nsIWindowMediator> winMediator(
@@ -222,7 +245,7 @@ class AsyncRevealOperation : public Runnable {
 class nsDriveEnumerator : public nsSimpleEnumerator,
                           public nsIDirectoryEnumerator {
  public:
-  nsDriveEnumerator();
+  explicit nsDriveEnumerator(bool aUseDOSDevicePathSyntax);
   NS_DECL_ISUPPORTS_INHERITED
   NS_DECL_NSISIMPLEENUMERATOR
   NS_FORWARD_NSISIMPLEENUMERATORBASE(nsSimpleEnumerator::)
@@ -258,6 +281,7 @@ class nsDriveEnumerator : public nsSimpleEnumerator,
   nsString mDrives;
   nsAString::const_iterator mStartOfCurrentDrive;
   nsAString::const_iterator mEndOfDrivesString;
+  const bool mUseDOSDevicePathSyntax;
 };
 
 //-----------------------------------------------------------------------------
@@ -503,12 +527,21 @@ static void FileTimeToPRTime(const FILETIME* aFiletime, PRTime* aPrtm) {
 // copied from nsprpub/pr/src/{io/prfile.c | md/windows/w95io.c} with some
 // changes : PR_GetFileInfo64, _PR_MD_GETFILEINFO64
 static nsresult GetFileInfo(const nsString& aName, PRFileInfo64* aInfo) {
-  WIN32_FILE_ATTRIBUTE_DATA fileData;
-
-  if (aName.IsEmpty() || aName.FindCharInSet(u"?*") != kNotFound) {
+  if (aName.IsEmpty()) {
     return NS_ERROR_INVALID_ARG;
   }
 
+  // Checking u"?*" for the file path excluding the kDevicePathSpecifier.
+  // ToDo: Check if checking "?" for the file path is still needed.
+  const int32_t offset = StringBeginsWith(aName, kDevicePathSpecifier)
+                             ? kDevicePathSpecifier.Length()
+                             : 0;
+
+  if (aName.FindCharInSet(u"?*", offset) != kNotFound) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  WIN32_FILE_ATTRIBUTE_DATA fileData;
   if (!::GetFileAttributesExW(aName.get(), GetFileExInfoStandard, &fileData)) {
     return ConvertWinError(GetLastError());
   }
@@ -546,9 +579,6 @@ static nsresult OpenDir(const nsString& aName, nsDir** aDir) {
   }
 
   *aDir = nullptr;
-  if (aName.Length() + 3 >= MAX_PATH) {
-    return NS_ERROR_FILE_NAME_TOO_LONG;
-  }
 
   nsDir* d = new nsDir();
   nsAutoString filename(aName);
@@ -762,9 +792,13 @@ NS_IMPL_ISUPPORTS_INHERITED(nsDirEnumerator, nsSimpleEnumerator,
 //-----------------------------------------------------------------------------
 
 nsLocalFile::nsLocalFile()
-    : mDirty(true), mResolveDirty(true), mFollowSymlinks(false) {}
+    : mDirty(true),
+      mResolveDirty(true),
+      mFollowSymlinks(false),
+      mUseDOSDevicePathSyntax(false) {}
 
-nsLocalFile::nsLocalFile(const nsAString& aFilePath) : mFollowSymlinks(false) {
+nsLocalFile::nsLocalFile(const nsAString& aFilePath)
+    : mFollowSymlinks(false), mUseDOSDevicePathSyntax(false) {
   InitWithPath(aFilePath);
 }
 
@@ -801,6 +835,7 @@ nsLocalFile::nsLocalFile(const nsLocalFile& aOther)
     : mDirty(true),
       mResolveDirty(true),
       mFollowSymlinks(aOther.mFollowSymlinks),
+      mUseDOSDevicePathSyntax(aOther.mUseDOSDevicePathSyntax),
       mWorkingPath(aOther.mWorkingPath) {}
 
 // Resolve the shortcut file from mWorkingPath and write the path
@@ -995,6 +1030,15 @@ nsLocalFile::InitWithPath(const nsAString& aFilePath) {
     mWorkingPath.Truncate(mWorkingPath.Length() - 1);
   }
 
+  // Bug 1626514: make sure that we don't end up with multiple prefixes.
+
+  // Prepend the "\\?\" prefix if the useDOSDevicePathSyntax is set and the path
+  // starts with a disk designator and backslash.
+  if (mUseDOSDevicePathSyntax &&
+      FilePreferences::StartsWithDiskDesignatorAndBackslash(mWorkingPath)) {
+    mWorkingPath = kDevicePathSpecifier + mWorkingPath;
+  }
+
   return NS_OK;
 }
 
@@ -1526,6 +1570,9 @@ nsLocalFile::SetLeafName(const nsAString& aLeafName) {
 
 NS_IMETHODIMP
 nsLocalFile::GetPath(nsAString& aResult) {
+  MOZ_ASSERT_IF(
+      mUseDOSDevicePathSyntax,
+      !FilePreferences::StartsWithDiskDesignatorAndBackslash(mWorkingPath));
   aResult = mWorkingPath;
   return NS_OK;
 }
@@ -1676,6 +1723,24 @@ nsresult nsLocalFile::CopySingleFile(nsIFile* aSourceFile, nsIFile* aDestParent,
     return rv;
   }
 
+#ifdef DEBUG
+  nsCOMPtr<nsILocalFileWin> srcWinFile = do_QueryInterface(aSourceFile);
+  MOZ_ASSERT(srcWinFile);
+
+  bool srcUseDOSDevicePathSyntax;
+  srcWinFile->GetUseDOSDevicePathSyntax(&srcUseDOSDevicePathSyntax);
+
+  nsCOMPtr<nsILocalFileWin> destWinFile = do_QueryInterface(aDestParent);
+  MOZ_ASSERT(destWinFile);
+
+  bool destUseDOSDevicePathSyntax;
+  destWinFile->GetUseDOSDevicePathSyntax(&destUseDOSDevicePathSyntax);
+
+  MOZ_ASSERT(srcUseDOSDevicePathSyntax == destUseDOSDevicePathSyntax,
+             "Copy or Move files with different values for "
+             "useDOSDevicePathSyntax would fail");
+#endif
+
   if (FilePreferences::IsBlockedUNCPath(destPath)) {
     return NS_ERROR_FILE_ACCESS_DENIED;
   }
@@ -2606,8 +2671,8 @@ nsLocalFile::GetParent(nsIFile** aParent) {
 
   nsCOMPtr<nsIFile> localFile;
   nsresult rv =
-      NS_NewLocalFile(parentPath, mFollowSymlinks, getter_AddRefs(localFile));
-
+      NewLocalFile(parentPath, mFollowSymlinks, mUseDOSDevicePathSyntax,
+                   getter_AddRefs(localFile));
   if (NS_FAILED(rv)) {
     return rv;
   }
@@ -2863,8 +2928,32 @@ nsLocalFile::Equals(nsIFile* aInFile, bool* aResult) {
   nsAutoString inFilePath;
   lf->GetCanonicalPath(inFilePath);
 
+  bool inUseDOSDevicePathSyntax;
+  lf->GetUseDOSDevicePathSyntax(&inUseDOSDevicePathSyntax);
+
+  // Remove the prefix for both inFilePath and mShortWorkingPath if the
+  // useDOSDevicePathSyntax from them are not the same.
+  // This is added because of Omnijar. It compare files from different moduals
+  // with itself
+  nsAutoString shortWorkingPath;
+  if (inUseDOSDevicePathSyntax == mUseDOSDevicePathSyntax) {
+    shortWorkingPath = mShortWorkingPath;
+  } else if (inUseDOSDevicePathSyntax &&
+             StringBeginsWith(inFilePath, kDevicePathSpecifier)) {
+    MOZ_ASSERT(!StringBeginsWith(mShortWorkingPath, kDevicePathSpecifier));
+
+    shortWorkingPath = mShortWorkingPath;
+    inFilePath = Substring(inFilePath, kDevicePathSpecifier.Length());
+  } else if (mUseDOSDevicePathSyntax &&
+             StringBeginsWith(mShortWorkingPath, kDevicePathSpecifier)) {
+    MOZ_ASSERT(!StringBeginsWith(inFilePath, kDevicePathSpecifier));
+
+    shortWorkingPath =
+        Substring(mShortWorkingPath, kDevicePathSpecifier.Length());
+  }
+
   // Ok : Win9x
-  *aResult = _wcsicmp(mShortWorkingPath.get(), inFilePath.get()) == 0;
+  *aResult = _wcsicmp(shortWorkingPath.get(), inFilePath.get()) == 0;
 
   return NS_OK;
 }
@@ -2904,6 +2993,10 @@ nsLocalFile::GetTarget(nsAString& aResult) {
   aResult.Truncate();
   Resolve();
 
+  MOZ_ASSERT_IF(
+      mUseDOSDevicePathSyntax,
+      !FilePreferences::StartsWithDiskDesignatorAndBackslash(mResolvedPath));
+
   aResult = mResolvedPath;
   return NS_OK;
 }
@@ -2926,7 +3019,8 @@ nsLocalFile::GetDirectoryEntriesImpl(nsIDirectoryEnumerator** aEntries) {
 
   *aEntries = nullptr;
   if (mWorkingPath.EqualsLiteral("\\\\.")) {
-    RefPtr<nsDriveEnumerator> drives = new nsDriveEnumerator;
+    RefPtr<nsDriveEnumerator> drives =
+        new nsDriveEnumerator(mUseDOSDevicePathSyntax);
     rv = drives->Init();
     if (NS_FAILED(rv)) {
       return rv;
@@ -3002,6 +3096,38 @@ nsLocalFile::SetFileAttributesWin(uint32_t aAttribs) {
   return NS_OK;
 }
 
+NS_IMETHODIMP
+nsLocalFile::GetUseDOSDevicePathSyntax(bool* aUseDOSDevicePathSyntax) {
+  MOZ_ASSERT(aUseDOSDevicePathSyntax);
+
+  *aUseDOSDevicePathSyntax = mUseDOSDevicePathSyntax;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsLocalFile::SetUseDOSDevicePathSyntax(bool aUseDOSDevicePathSyntax) {
+  if (mUseDOSDevicePathSyntax == aUseDOSDevicePathSyntax) {
+    return NS_OK;
+  }
+
+  if (mUseDOSDevicePathSyntax) {
+    if (StringBeginsWith(mWorkingPath, kDevicePathSpecifier)) {
+      MakeDirty();
+      // Remove the prefix
+      mWorkingPath = Substring(mWorkingPath, kDevicePathSpecifier.Length());
+    }
+  } else {
+    if (FilePreferences::StartsWithDiskDesignatorAndBackslash(mWorkingPath)) {
+      MakeDirty();
+      // Prepend the prefix
+      mWorkingPath = kDevicePathSpecifier + mWorkingPath;
+    }
+  }
+
+  mUseDOSDevicePathSyntax = aUseDOSDevicePathSyntax;
+  return NS_OK;
+}
+
 NS_IMETHODIMP
 nsLocalFile::Reveal() {
   // This API should be main thread only
@@ -3279,7 +3405,8 @@ void nsLocalFile::EnsureShortPath() {
 NS_IMPL_ISUPPORTS_INHERITED(nsDriveEnumerator, nsSimpleEnumerator,
                             nsIDirectoryEnumerator)
 
-nsDriveEnumerator::nsDriveEnumerator() {}
+nsDriveEnumerator::nsDriveEnumerator(bool aUseDOSDevicePathSyntax)
+    : mUseDOSDevicePathSyntax(aUseDOSDevicePathSyntax) {}
 
 nsDriveEnumerator::~nsDriveEnumerator() {}
 
@@ -3323,7 +3450,7 @@ nsDriveEnumerator::GetNext(nsISupports** aNext) {
   mStartOfCurrentDrive = ++driveEnd;
 
   nsIFile* file;
-  nsresult rv = NS_NewLocalFile(drive, false, &file);
+  nsresult rv = NewLocalFile(drive, false, mUseDOSDevicePathSyntax, &file);
 
   *aNext = file;
   return rv;
diff --git a/xpcom/io/nsLocalFileWin.h b/xpcom/io/nsLocalFileWin.h
index 199c8d8846..a9341efcc2 100644
--- a/xpcom/io/nsLocalFileWin.h
+++ b/xpcom/io/nsLocalFileWin.h
@@ -61,6 +61,8 @@ class nsLocalFile final : public nsILocalFileWin {
   bool mResolveDirty;
   bool mFollowSymlinks;  // should we follow symlinks when working on this file
 
+  bool mUseDOSDevicePathSyntax;
+
   // this string will always be in native format!
   nsString mWorkingPath;
 
diff --git a/xpcom/io/nsStreamUtils.cpp b/xpcom/io/nsStreamUtils.cpp
index 9ec53974b8..677733b0d8 100644
--- a/xpcom/io/nsStreamUtils.cpp
+++ b/xpcom/io/nsStreamUtils.cpp
@@ -5,7 +5,6 @@
 #include "mozilla/Mutex.h"
 #include "mozilla/Attributes.h"
 #include "nsStreamUtils.h"
-#include "nsAutoPtr.h"
 #include "nsCOMPtr.h"
 #include "nsICloneableInputStream.h"
 #include "nsIEventTarget.h"
diff --git a/xpcom/io/nsUnicharInputStream.cpp b/xpcom/io/nsUnicharInputStream.cpp
index 2d771a0e02..63f5bd372d 100644
--- a/xpcom/io/nsUnicharInputStream.cpp
+++ b/xpcom/io/nsUnicharInputStream.cpp
@@ -6,7 +6,6 @@
 #include "nsIInputStream.h"
 #include "nsString.h"
 #include "nsTArray.h"
-#include "nsAutoPtr.h"
 #include "nsCRT.h"
 #include "nsStreamUtils.h"
 #include "nsConverterInputStream.h"
diff --git a/xpcom/reflect/xptcall/xptcprivate.h b/xpcom/reflect/xptcall/xptcprivate.h
index 26ad270cad..ec66b0d969 100644
--- a/xpcom/reflect/xptcall/xptcprivate.h
+++ b/xpcom/reflect/xptcall/xptcprivate.h
@@ -8,7 +8,6 @@
 #define xptcprivate_h___
 
 #include "xptcall.h"
-#include "nsAutoPtr.h"
 #include "mozilla/Attributes.h"
 
 #if !defined(__ia64) || \
diff --git a/xpcom/reflect/xptinfo/xptcodegen.py b/xpcom/reflect/xptinfo/xptcodegen.py
index 901c92a0f1..1d70c9ada8 100644
--- a/xpcom/reflect/xptinfo/xptcodegen.py
+++ b/xpcom/reflect/xptinfo/xptcodegen.py
@@ -179,7 +179,7 @@ utility_types = [
 
 # Core of the code generator. Takes a list of raw JSON XPT interfaces, and
 # writes out a file containing the necessary static declarations into fd.
-def link_to_cpp(interfaces, fd):
+def link_to_cpp(interfaces, fd, header_fd):
     # Perfect Hash from IID to interface.
     iid_phf = PerfectHash(interfaces, PHFSIZE,
                           key=lambda i: iid_bytes(i['uuid']))
@@ -445,8 +445,20 @@ def link_to_cpp(interfaces, fd):
     for iface in iid_phf.entries:
         lower_iface(iface)
 
-    # Write out the final output file
+    # Write out the final output files
     fd.write("/* THIS FILE WAS GENERATED BY xptcodegen.py - DO NOT EDIT */\n\n")
+    header_fd.write("/* THIS FILE WAS GENERATED BY xptcodegen.py - DO NOT EDIT */\n\n")
+
+    header_fd.write("""
+enum class nsXPTInterface : uint16_t {
+""")
+
+    for entry in iid_phf.entries:
+        header_fd.write("  %s,\n" % entry['name'])
+
+    header_fd.write("""
+};
+""")
 
     # Include any bindings files which we need to include for webidl types
     for include in sorted(includes):
@@ -545,7 +557,7 @@ const uint16_t sInterfacesSize = mozilla::ArrayLength(sInterfaces);
 """)
 
 
-def link_and_write(files, outfile):
+def link_and_write(files, outfile, outheader):
     interfaces = []
     for file in files:
         with open(file, 'r') as fd:
@@ -559,7 +571,7 @@ def link_and_write(files, outfile):
         iids.add(interface['uuid'])
         names.add(interface['name'])
 
-    link_to_cpp(interfaces, outfile)
+    link_to_cpp(interfaces, outfile, outheader)
 
 
 def main():
@@ -568,11 +580,12 @@ def main():
 
     parser = ArgumentParser()
     parser.add_argument('outfile', help='Output C++ file to generate')
+    parser.add_argument('outheader', help='Output C++ header file to generate')
     parser.add_argument('xpts', nargs='*', help='source xpt files')
 
     args = parser.parse_args(sys.argv[1:])
-    with open(args.outfile, 'w') as fd:
-        link_and_write(args.xpts, fd)
+    with open(args.outfile, 'w') as fd, open(args.outheader, 'w') as header_fd:
+        link_and_write(args.xpts, fd, header_fd)
 
 
 if __name__ == '__main__':
diff --git a/xpcom/reflect/xptinfo/xptinfo.h b/xpcom/reflect/xptinfo/xptinfo.h
index 952cc7857a..a0c5fb3cc1 100644
--- a/xpcom/reflect/xptinfo/xptinfo.h
+++ b/xpcom/reflect/xptinfo/xptinfo.h
@@ -19,6 +19,7 @@
 #include "js/Value.h"
 #include "nsString.h"
 #include "nsTArray.h"
+#include "xptdata.h"
 
 // Forward Declarations
 namespace mozilla {
@@ -67,6 +68,10 @@ struct nsXPTInterfaceInfo {
     return xpt::detail::InterfaceByName(aName);
   }
 
+  static const nsXPTInterfaceInfo* Get(nsXPTInterface aID) {
+    return ByIndex(uint16_t(aID));
+  }
+
   // These are only needed for Components_interfaces's enumerator.
   static const nsXPTInterfaceInfo* ByIndex(uint16_t aIndex) {
     // NOTE: We add 1 here, as the internal index 0 is reserved for null.
diff --git a/xpcom/rust/gtest/nsstring/Test.cpp b/xpcom/rust/gtest/nsstring/Test.cpp
index b0adec7c52..c601b52ee7 100644
--- a/xpcom/rust/gtest/nsstring/Test.cpp
+++ b/xpcom/rust/gtest/nsstring/Test.cpp
@@ -1,5 +1,6 @@
 #include "gtest/gtest.h"
 #include <stdint.h>
+#include <utility>
 #include "nsString.h"
 
 extern "C" {
@@ -22,23 +23,23 @@ void GTest_ExpectFailure(const char* aMessage) { EXPECT_STREQ(aMessage, ""); }
 SIZE_ALIGN_CHECK(nsString)
 SIZE_ALIGN_CHECK(nsCString)
 
-#define MEMBER_CHECK(Clazz, Member)                                           \
-  extern "C" void Rust_Test_Member_##Clazz##_##Member(                        \
-      size_t* size, size_t* align, size_t* offset);                           \
-  TEST(RustNsString, ReprMember_##Clazz##_##Member)                           \
-  {                                                                           \
-    class Hack : public Clazz {                                               \
-     public:                                                                  \
-      static void RunTest() {                                                 \
-        size_t size, align, offset;                                           \
-        Rust_Test_Member_##Clazz##_##Member(&size, &align, &offset);          \
-        EXPECT_EQ(size, sizeof(mozilla::DeclVal<Hack>().Member));             \
-        EXPECT_EQ(align, alignof(decltype(mozilla::DeclVal<Hack>().Member))); \
-        EXPECT_EQ(offset, offsetof(Hack, Member));                            \
-      }                                                                       \
-    };                                                                        \
-    static_assert(sizeof(Clazz) == sizeof(Hack), "Hack matches class");       \
-    Hack::RunTest();                                                          \
+#define MEMBER_CHECK(Clazz, Member)                                       \
+  extern "C" void Rust_Test_Member_##Clazz##_##Member(                    \
+      size_t* size, size_t* align, size_t* offset);                       \
+  TEST(RustNsString, ReprMember_##Clazz##_##Member)                       \
+  {                                                                       \
+    class Hack : public Clazz {                                           \
+     public:                                                              \
+      static void RunTest() {                                             \
+        size_t size, align, offset;                                       \
+        Rust_Test_Member_##Clazz##_##Member(&size, &align, &offset);      \
+        EXPECT_EQ(size, sizeof(std::declval<Hack>().Member));             \
+        EXPECT_EQ(align, alignof(decltype(std::declval<Hack>().Member))); \
+        EXPECT_EQ(offset, offsetof(Hack, Member));                        \
+      }                                                                   \
+    };                                                                    \
+    static_assert(sizeof(Clazz) == sizeof(Hack), "Hack matches class");   \
+    Hack::RunTest();                                                      \
   }
 
 MEMBER_CHECK(nsString, mData)
diff --git a/xpcom/rust/nsstring/src/lib.rs b/xpcom/rust/nsstring/src/lib.rs
index dd95c72ee5..2485a3598b 100644
--- a/xpcom/rust/nsstring/src/lib.rs
+++ b/xpcom/rust/nsstring/src/lib.rs
@@ -113,6 +113,9 @@
 //! which invoke their member's destructors through C++ code.
 
 #![allow(non_camel_case_types)]
+#![allow(clippy::missing_safety_doc)]
+#![allow(clippy::new_without_default)]
+#![allow(clippy::result_unit_err)]
 
 use bitflags::bitflags;
 use std::borrow;
@@ -277,7 +280,7 @@ impl<'a> Drop for nsAStringBulkWriteHandle<'a> {
             let mut this = self.string.as_repr_mut();
             this.as_mut().length = 1u32;
             *(this.as_mut().data.as_mut()) = 0xFFFDu16;
-            *(this.as_mut().data.as_ptr().offset(1isize)) = 0;
+            *(this.as_mut().data.as_ptr().add(1)) = 0;
         }
     }
 }
@@ -307,13 +310,13 @@ impl<'a> Drop for nsACStringBulkWriteHandle<'a> {
             if self.capacity >= 3 {
                 this.as_mut().length = 3u32;
                 *(this.as_mut().data.as_mut()) = 0xEFu8;
-                *(this.as_mut().data.as_ptr().offset(1isize)) = 0xBFu8;
-                *(this.as_mut().data.as_ptr().offset(2isize)) = 0xBDu8;
-                *(this.as_mut().data.as_ptr().offset(3isize)) = 0;
+                *(this.as_mut().data.as_ptr().add(1)) = 0xBFu8;
+                *(this.as_mut().data.as_ptr().add(2)) = 0xBDu8;
+                *(this.as_mut().data.as_ptr().add(3)) = 0;
             } else {
                 this.as_mut().length = 1u32;
                 *(this.as_mut().data.as_mut()) = 0x1Au8; // U+FFFD doesn't fit
-                *(this.as_mut().data.as_ptr().offset(1isize)) = 0;
+                *(this.as_mut().data.as_ptr().add(1)) = 0;
             }
         }
     }
@@ -378,7 +381,7 @@ macro_rules! define_string_types {
             type Target = $AString;
             fn deref(&self) -> &$AString {
                 unsafe {
-                    mem::transmute(self)
+                    &*(self as *const _ as *const $AString)
                 }
             }
         }
@@ -386,7 +389,7 @@ macro_rules! define_string_types {
         impl DerefMut for $StringRepr {
             fn deref_mut(&mut self) -> &mut $AString {
                 unsafe {
-                    mem::transmute(self)
+                    &mut *(self as *mut _ as *mut $AString)
                 }
             }
         }
@@ -441,7 +444,7 @@ macro_rules! define_string_types {
                 unsafe {
                     let mut this = self.string.as_repr_mut();
                     this.as_mut().length = length as u32;
-                    *(this.as_mut().data.as_ptr().offset(length as isize)) = 0;
+                    *(this.as_mut().data.as_ptr().add(length)) = 0;
                     if cfg!(debug_assertions) {
                         // Overwrite the unused part in debug builds. Note
                         // that capacity doesn't include space for the zero
@@ -450,7 +453,7 @@ macro_rules! define_string_types {
                         // not reflected in the capacity number.
                         // write_bytes() takes care of multiplying the length
                         // by the size of T.
-                        ptr::write_bytes(this.as_mut().data.as_ptr().offset((length + 1) as isize),
+                        ptr::write_bytes(this.as_mut().data.as_ptr().add(length + 1),
                                          0xE4u8,
                                          self.capacity - length);
                     }
@@ -649,9 +652,9 @@ macro_rules! define_string_types {
 
             fn as_repr(&self) -> &$StringRepr {
                 // All $AString values point to a struct prefix which is
-                // identical to $StringRepr, this we can transmute `self`
-                // into $StringRepr to get the reference to the underlying
-                // data.
+                // identical to $StringRepr, thus we can cast `self`
+                // into *const $StringRepr to get the reference to the
+                // underlying data.
                 unsafe {
                     &*(self as *const _ as *const $StringRepr)
                 }
@@ -684,10 +687,10 @@ macro_rules! define_string_types {
             fn deref(&self) -> &[$char_t] {
                 unsafe {
                     // All $AString values point to a struct prefix which is
-                    // identical to $StringRepr, this we can transmute `self`
-                    // into $StringRepr to get the reference to the underlying
-                    // data.
-                    let this: &$StringRepr = mem::transmute(self);
+                    // identical to $StringRepr, thus we can cast `self`
+                    // into *const $StringRepr to get the reference to the
+                    // underlying data.
+                    let this = &*(self as *const _ as *const $StringRepr);
                     slice::from_raw_parts(this.data.as_ptr(), this.length as usize)
                 }
             }
@@ -949,7 +952,7 @@ macro_rules! define_string_types {
                 $String {
                     hdr: $StringRepr {
                         data: unsafe { ptr::NonNull::new_unchecked(ptr) },
-                        length: length,
+                        length,
                         dataflags: DataFlags::OWNED | DataFlags::TERMINATED,
                         classflags: ClassFlags::NULL_TERMINATED,
                     }
@@ -1254,6 +1257,7 @@ impl nsAString {
     ///
     /// This is needed because the default ToString implementation goes through
     /// fmt::Display, and thus allocates the string twice.
+    #[allow(clippy::inherent_to_string_shadow_display)]
     pub fn to_string(&self) -> String {
         String::from_utf16_lossy(&self[..])
     }
@@ -1348,26 +1352,22 @@ pub mod test_helpers {
         ($T:ty, $fname:ident) => {
             #[no_mangle]
             #[allow(non_snake_case)]
-            pub extern "C" fn $fname(size: *mut usize, align: *mut usize) {
-                unsafe {
-                    *size = mem::size_of::<$T>();
-                    *align = mem::align_of::<$T>();
-                }
+            pub unsafe extern "C" fn $fname(size: *mut usize, align: *mut usize) {
+                *size = mem::size_of::<$T>();
+                *align = mem::align_of::<$T>();
             }
         };
         ($T:ty, $U:ty, $V:ty, $fname:ident) => {
             #[no_mangle]
             #[allow(non_snake_case)]
-            pub extern "C" fn $fname(size: *mut usize, align: *mut usize) {
-                unsafe {
-                    *size = mem::size_of::<$T>();
-                    *align = mem::align_of::<$T>();
+            pub unsafe extern "C" fn $fname(size: *mut usize, align: *mut usize) {
+                *size = mem::size_of::<$T>();
+                *align = mem::align_of::<$T>();
 
-                    assert_eq!(*size, mem::size_of::<$U>());
-                    assert_eq!(*align, mem::align_of::<$U>());
-                    assert_eq!(*size, mem::size_of::<$V>());
-                    assert_eq!(*align, mem::align_of::<$V>());
-                }
+                assert_eq!(*size, mem::size_of::<$U>());
+                assert_eq!(*align, mem::align_of::<$U>());
+                assert_eq!(*size, mem::size_of::<$V>());
+                assert_eq!(*align, mem::align_of::<$V>());
             }
         };
     }
@@ -1395,38 +1395,36 @@ pub mod test_helpers {
         ($T:ty, $U:ty, $V:ty, $member:ident, $method:ident) => {
             #[no_mangle]
             #[allow(non_snake_case)]
-            pub extern "C" fn $method(size: *mut usize, align: *mut usize, offset: *mut usize) {
-                unsafe {
-                    // Create a temporary value of type T to get offsets, sizes
-                    // and alignments from.
-                    let tmp: mem::MaybeUninit<$T> = mem::MaybeUninit::uninit();
-                    // FIXME: This should use &raw references when available,
-                    // this is technically UB as it creates a reference to
-                    // uninitialized memory, but there's no better way to do
-                    // this right now.
-                    let tmp = &*tmp.as_ptr();
-                    *size = mem::size_of_val(&tmp.$member);
-                    *align = mem::align_of_val(&tmp.$member);
-                    *offset = (&tmp.$member as *const _ as usize) - (tmp as *const $T as usize);
+            pub unsafe extern "C" fn $method(size: *mut usize, align: *mut usize, offset: *mut usize) {
+                // Create a temporary value of type T to get offsets, sizes
+                // and alignments from.
+                let tmp: mem::MaybeUninit<$T> = mem::MaybeUninit::uninit();
+                // FIXME: This should use &raw references when available,
+                // this is technically UB as it creates a reference to
+                // uninitialized memory, but there's no better way to do
+                // this right now.
+                let tmp = &*tmp.as_ptr();
+                *size = mem::size_of_val(&tmp.$member);
+                *align = mem::align_of_val(&tmp.$member);
+                *offset = (&tmp.$member as *const _ as usize) - (tmp as *const $T as usize);
 
-                    let tmp: mem::MaybeUninit<$U> = mem::MaybeUninit::uninit();
-                    let tmp = &*tmp.as_ptr();
-                    assert_eq!(*size, mem::size_of_val(&tmp.hdr.$member));
-                    assert_eq!(*align, mem::align_of_val(&tmp.hdr.$member));
-                    assert_eq!(
-                        *offset,
-                        (&tmp.hdr.$member as *const _ as usize) - (tmp as *const $U as usize)
-                    );
+                let tmp: mem::MaybeUninit<$U> = mem::MaybeUninit::uninit();
+                let tmp = &*tmp.as_ptr();
+                assert_eq!(*size, mem::size_of_val(&tmp.hdr.$member));
+                assert_eq!(*align, mem::align_of_val(&tmp.hdr.$member));
+                assert_eq!(
+                    *offset,
+                    (&tmp.hdr.$member as *const _ as usize) - (tmp as *const $U as usize)
+                );
 
-                    let tmp: mem::MaybeUninit<$V> = mem::MaybeUninit::uninit();
-                    let tmp = &*tmp.as_ptr();
-                    assert_eq!(*size, mem::size_of_val(&tmp.hdr.$member));
-                    assert_eq!(*align, mem::align_of_val(&tmp.hdr.$member));
-                    assert_eq!(
-                        *offset,
-                        (&tmp.hdr.$member as *const _ as usize) - (tmp as *const $V as usize)
-                    );
-                }
+                let tmp: mem::MaybeUninit<$V> = mem::MaybeUninit::uninit();
+                let tmp = &*tmp.as_ptr();
+                assert_eq!(*size, mem::size_of_val(&tmp.hdr.$member));
+                assert_eq!(*align, mem::align_of_val(&tmp.hdr.$member));
+                assert_eq!(
+                    *offset,
+                    (&tmp.hdr.$member as *const _ as usize) - (tmp as *const $V as usize)
+                );
             }
         };
     }
@@ -1490,7 +1488,7 @@ pub mod test_helpers {
 
     #[no_mangle]
     #[allow(non_snake_case)]
-    pub extern "C" fn Rust_Test_NsStringFlags(
+    pub unsafe extern "C" fn Rust_Test_NsStringFlags(
         f_terminated: *mut u16,
         f_voided: *mut u16,
         f_refcounted: *mut u16,
@@ -1500,29 +1498,25 @@ pub mod test_helpers {
         f_class_inline: *mut u16,
         f_class_null_terminated: *mut u16,
     ) {
-        unsafe {
-            *f_terminated = DataFlags::TERMINATED.bits();
-            *f_voided = DataFlags::VOIDED.bits();
-            *f_refcounted = DataFlags::REFCOUNTED.bits();
-            *f_owned = DataFlags::OWNED.bits();
-            *f_inline = DataFlags::INLINE.bits();
-            *f_literal = DataFlags::LITERAL.bits();
-            *f_class_inline = ClassFlags::INLINE.bits();
-            *f_class_null_terminated = ClassFlags::NULL_TERMINATED.bits();
-        }
+        *f_terminated = DataFlags::TERMINATED.bits();
+        *f_voided = DataFlags::VOIDED.bits();
+        *f_refcounted = DataFlags::REFCOUNTED.bits();
+        *f_owned = DataFlags::OWNED.bits();
+        *f_inline = DataFlags::INLINE.bits();
+        *f_literal = DataFlags::LITERAL.bits();
+        *f_class_inline = ClassFlags::INLINE.bits();
+        *f_class_null_terminated = ClassFlags::NULL_TERMINATED.bits();
     }
 
     #[no_mangle]
     #[allow(non_snake_case)]
-    pub extern "C" fn Rust_InlineCapacityFromRust(
+    pub unsafe extern "C" fn Rust_InlineCapacityFromRust(
         cstring: *const nsACString,
         string: *const nsAString,
         cstring_capacity: *mut usize,
         string_capacity: *mut usize,
     ) {
-        unsafe {
-            *cstring_capacity = (*cstring).inline_capacity().unwrap();
-            *string_capacity = (*string).inline_capacity().unwrap();
-        }
+        *cstring_capacity = (*cstring).inline_capacity().unwrap();
+        *string_capacity = (*string).inline_capacity().unwrap();
     }
 }
diff --git a/xpcom/string/nsTSubstring.h b/xpcom/string/nsTSubstring.h
index 8f1eb86239..b570dd4ed6 100644
--- a/xpcom/string/nsTSubstring.h
+++ b/xpcom/string/nsTSubstring.h
@@ -15,6 +15,7 @@
 #include "mozilla/MemoryReporting.h"
 #include "mozilla/IntegerTypeTraits.h"
 #include "mozilla/Result.h"
+#include "mozilla/ResultExtensions.h"
 #include "mozilla/Span.h"
 #include "mozilla/Unused.h"
 
@@ -172,16 +173,8 @@ class BulkWriteHandle final {
   mozilla::Result<mozilla::Ok, nsresult> RestartBulkWrite(
       size_type aCapacity, size_type aPrefixToPreserve, bool aAllowShrinking) {
     MOZ_ASSERT(mString);
-    auto r = mString->StartBulkWriteImpl(aCapacity, aPrefixToPreserve,
-                                         aAllowShrinking);
-    if (MOZ_UNLIKELY(r.isErr())) {
-      nsresult rv = r.unwrapErr();
-      // MOZ_TRY or manual unwrapErr() without the intermediate
-      // assignment complains about an incomplete type.
-      // andThen() is not enabled on r.
-      return mozilla::Err(rv);
-    }
-    mCapacity = r.unwrap();
+    MOZ_TRY_VAR(mCapacity, mString->StartBulkWriteImpl(
+                               aCapacity, aPrefixToPreserve, aAllowShrinking));
     return mozilla::Ok();
   }
 
diff --git a/xpcom/tests/TestHarness.h b/xpcom/tests/TestHarness.h
index 3c90c52306..0dafba67f4 100644
--- a/xpcom/tests/TestHarness.h
+++ b/xpcom/tests/TestHarness.h
@@ -18,7 +18,6 @@
 #include "nsComponentManagerUtils.h"
 #include "nsServiceManagerUtils.h"
 #include "nsCOMPtr.h"
-#include "nsAutoPtr.h"
 #include "nsString.h"
 #include "nsAppDirectoryServiceDefs.h"
 #include "nsDirectoryServiceDefs.h"
diff --git a/xpcom/tests/gtest/TestArrayAlgorithm.cpp b/xpcom/tests/gtest/TestArrayAlgorithm.cpp
new file mode 100644
index 0000000000..054a43097d
--- /dev/null
+++ b/xpcom/tests/gtest/TestArrayAlgorithm.cpp
@@ -0,0 +1,106 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "gtest/gtest.h"
+
+#include "mozilla/ArrayAlgorithm.h"
+#include "mozilla/Result.h"
+#include "mozilla/ResultExtensions.h"
+#include "nsTArray.h"
+
+using namespace mozilla;
+using std::begin;
+using std::end;
+
+namespace {
+constexpr static int32_t arr1[3] = {1, 2, 3};
+}
+
+TEST(nsAlgorithm_TransformIntoNewArrayAbortOnErr, NoError_Fallible)
+{
+  auto res = TransformIntoNewArrayAbortOnErr(
+      begin(arr1), end(arr1),
+      [](const int32_t value) -> Result<int64_t, nsresult> {
+        return value * 10;
+      },
+      fallible);
+  ASSERT_TRUE(res.isOk());
+  const nsTArray<int64_t>& out = res.inspect();
+
+  const nsTArray<int64_t> expected = {10, 20, 30};
+  ASSERT_EQ(expected, out);
+}
+
+TEST(nsAlgorithm_TransformIntoNewArrayAbortOnErr, NoError_Fallible_Range)
+{
+  auto res = TransformIntoNewArrayAbortOnErr(
+      arr1,
+      [](const int32_t value) -> Result<int64_t, nsresult> {
+        return value * 10;
+      },
+      fallible);
+  ASSERT_TRUE(res.isOk());
+  const nsTArray<int64_t>& out = res.inspect();
+
+  const nsTArray<int64_t> expected = {10, 20, 30};
+  ASSERT_EQ(expected, out);
+}
+
+TEST(nsAlgorithm_TransformIntoNewArrayAbortOnErr, ErrorOnOther_Fallible)
+{
+  auto res = TransformIntoNewArrayAbortOnErr(
+      begin(arr1), end(arr1),
+      [](const int32_t value) -> Result<int64_t, nsresult> {
+        if (value > 1) {
+          return Err(NS_ERROR_FAILURE);
+        }
+        return value * 10;
+      },
+      fallible);
+  ASSERT_TRUE(res.isErr());
+  ASSERT_EQ(NS_ERROR_FAILURE, res.inspectErr());
+}
+
+TEST(nsAlgorithm_TransformIntoNewArray, NoError)
+{
+  auto res = TransformIntoNewArray(
+      begin(arr1), end(arr1),
+      [](const int32_t value) -> int64_t { return value * 10; });
+
+  const nsTArray<int64_t> expected = {10, 20, 30};
+  ASSERT_EQ(expected, res);
+}
+
+TEST(nsAlgorithm_TransformIntoNewArray, NoError_Range)
+{
+  auto res = TransformIntoNewArray(
+      arr1, [](const int32_t value) -> int64_t { return value * 10; });
+
+  const nsTArray<int64_t> expected = {10, 20, 30};
+  ASSERT_EQ(expected, res);
+}
+
+TEST(nsAlgorithm_TransformIntoNewArray, NoError_Fallible)
+{
+  auto res = TransformIntoNewArray(
+      begin(arr1), end(arr1),
+      [](const int32_t value) -> int64_t { return value * 10; }, fallible);
+  ASSERT_TRUE(res.isOk());
+  const nsTArray<int64_t>& out = res.inspect();
+
+  const nsTArray<int64_t> expected = {10, 20, 30};
+  ASSERT_EQ(expected, out);
+}
+
+TEST(nsAlgorithm_TransformIntoNewArray, NoError_Fallible_Range)
+{
+  auto res = TransformIntoNewArray(
+      arr1, [](const int32_t value) -> int64_t { return value * 10; },
+      fallible);
+  ASSERT_TRUE(res.isOk());
+  const nsTArray<int64_t>& out = res.inspect();
+
+  const nsTArray<int64_t> expected = {10, 20, 30};
+  ASSERT_EQ(expected, out);
+}
diff --git a/xpcom/tests/gtest/TestCallTemplates.cpp b/xpcom/tests/gtest/TestCallTemplates.cpp
index 48d462406c..15dc4a28e2 100644
--- a/xpcom/tests/gtest/TestCallTemplates.cpp
+++ b/xpcom/tests/gtest/TestCallTemplates.cpp
@@ -14,7 +14,6 @@
 #include "nsIInterfaceRequestorUtils.h"
 #include "nsComponentManagerUtils.h"
 #include "nsServiceManagerUtils.h"
-#include "nsAutoPtr.h"
 #include "mozilla/Attributes.h"
 
 #define NS_ITESTSERVICE_IID                          \
diff --git a/xpcom/tests/gtest/TestExpirationTracker.cpp b/xpcom/tests/gtest/TestExpirationTracker.cpp
index accfb38b4b..4b6d78f426 100644
--- a/xpcom/tests/gtest/TestExpirationTracker.cpp
+++ b/xpcom/tests/gtest/TestExpirationTracker.cpp
@@ -7,7 +7,6 @@
 #include <prthread.h>
 #include "nsExpirationTracker.h"
 #include "nsMemory.h"
-#include "nsAutoPtr.h"
 #include "nsString.h"
 #include "nsDirectoryServiceDefs.h"
 #include "nsDirectoryServiceUtils.h"
diff --git a/xpcom/tests/gtest/TestFile.cpp b/xpcom/tests/gtest/TestFile.cpp
index 9d8bd78318..4319591ba2 100644
--- a/xpcom/tests/gtest/TestFile.cpp
+++ b/xpcom/tests/gtest/TestFile.cpp
@@ -6,24 +6,50 @@
 #include "prsystem.h"
 
 #include "nsIFile.h"
+#ifdef XP_WIN
+#  include "nsILocalFileWin.h"
+#endif
 #include "nsString.h"
 #include "nsDirectoryServiceDefs.h"
 #include "nsDirectoryServiceUtils.h"
+#include "nsPrintfCString.h"
 
 #include "gtest/gtest.h"
 
+#ifdef XP_WIN
+bool gTestWithPrefix_Win = false;
+#endif
+
 static bool VerifyResult(nsresult aRV, const char* aMsg) {
   bool failed = NS_FAILED(aRV);
   EXPECT_FALSE(failed) << aMsg << " rv=" << std::hex << (unsigned int)aRV;
   return !failed;
 }
 
+#ifdef XP_WIN
+static void SetUseDOSDevicePathSyntax(nsIFile* aFile) {
+  if (gTestWithPrefix_Win) {
+    nsresult rv;
+    nsCOMPtr<nsILocalFileWin> winFile = do_QueryInterface(aFile, &rv);
+    VerifyResult(rv, "Querying nsILocalFileWin");
+
+    MOZ_ASSERT(winFile);
+    winFile->SetUseDOSDevicePathSyntax(true);
+  }
+}
+#endif
+
 static already_AddRefed<nsIFile> NewFile(nsIFile* aBase) {
   nsresult rv;
   nsCOMPtr<nsIFile> file = do_CreateInstance(NS_LOCAL_FILE_CONTRACTID, &rv);
   VerifyResult(rv, "Creating nsIFile");
   rv = file->InitWithFile(aBase);
   VerifyResult(rv, "InitWithFile");
+
+#ifdef XP_WIN
+  SetUseDOSDevicePathSyntax(file);
+#endif
+
   return file.forget();
 }
 
@@ -364,15 +390,21 @@ static bool TestNormalizeNativePath(nsIFile* aBase, nsIFile* aStart) {
   return true;
 }
 
-TEST(TestFile, Tests)
-{
+static void SetupAndTestFunctions(const nsAString& aDirName,
+                                  bool aTestCreateUnique, bool aTestNormalize) {
   nsCOMPtr<nsIFile> base;
   nsresult rv = NS_GetSpecialDirectory(NS_OS_TEMP_DIR, getter_AddRefs(base));
   ASSERT_TRUE(VerifyResult(rv, "Getting temp directory"));
 
-  rv = base->AppendNative(nsDependentCString("mozfiletests"));
+#ifdef XP_WIN
+  SetUseDOSDevicePathSyntax(base);
+#endif
+
+  rv = base->Append(aDirName);
   ASSERT_TRUE(
-      VerifyResult(rv, "Appending mozfiletests to temp directory name"));
+      VerifyResult(rv, nsPrintfCString("Appending %s to temp directory name",
+                                       NS_ConvertUTF16toUTF8(aDirName).get())
+                           .get()));
 
   // Remove the directory in case tests failed and left it behind.
   // don't check result since it might not be there
@@ -383,8 +415,10 @@ TEST(TestFile, Tests)
   ASSERT_TRUE(VerifyResult(rv, "Creating temp directory"));
 
   // Now we can safely normalize the path
-  rv = base->Normalize();
-  ASSERT_TRUE(VerifyResult(rv, "Normalizing temp directory name"));
+  if (aTestNormalize) {
+    rv = base->Normalize();
+    ASSERT_TRUE(VerifyResult(rv, "Normalizing temp directory name"));
+  }
 
   // Initialize subdir object for later use
   nsCOMPtr<nsIFile> subdir = NewFile(base);
@@ -397,6 +431,12 @@ TEST(TestFile, Tests)
   // End setup code.
   // ---------------
 
+  // Test leafName
+  nsString leafName;
+  rv = base->GetLeafName(leafName);
+  ASSERT_TRUE(VerifyResult(rv, "Getting leafName"));
+  ASSERT_TRUE(leafName.Equals(aDirName));
+
   // Test path parsing
   ASSERT_TRUE(TestInvalidFileName(base, "a/b"));
   ASSERT_TRUE(TestParent(base, subdir));
@@ -422,16 +462,22 @@ TEST(TestFile, Tests)
   // Test copying across directoreis
   ASSERT_TRUE(TestCopy(base, subdir, "file4.txt", "file5.txt"));
 
-  // Run normalization tests while the directory exists
-  ASSERT_TRUE(TestNormalizeNativePath(base, subdir));
+  if (aTestNormalize) {
+    // Run normalization tests while the directory exists
+    ASSERT_TRUE(TestNormalizeNativePath(base, subdir));
+  }
 
   // Test recursive directory removal
   ASSERT_TRUE(TestRemove(base, "subdir", true));
 
-  ASSERT_TRUE(TestCreateUnique(base, "foo", nsIFile::NORMAL_FILE_TYPE, 0600));
-  ASSERT_TRUE(TestCreateUnique(base, "foo", nsIFile::NORMAL_FILE_TYPE, 0600));
-  ASSERT_TRUE(TestCreateUnique(base, "bar.xx", nsIFile::DIRECTORY_TYPE, 0700));
-  ASSERT_TRUE(TestCreateUnique(base, "bar.xx", nsIFile::DIRECTORY_TYPE, 0700));
+  if (aTestCreateUnique) {
+    ASSERT_TRUE(TestCreateUnique(base, "foo", nsIFile::NORMAL_FILE_TYPE, 0600));
+    ASSERT_TRUE(TestCreateUnique(base, "foo", nsIFile::NORMAL_FILE_TYPE, 0600));
+    ASSERT_TRUE(
+        TestCreateUnique(base, "bar.xx", nsIFile::DIRECTORY_TYPE, 0700));
+    ASSERT_TRUE(
+        TestCreateUnique(base, "bar.xx", nsIFile::DIRECTORY_TYPE, 0700));
+  }
 
   ASSERT_TRUE(
       TestDeleteOnClose(base, "file7.txt", PR_RDWR | PR_CREATE_FILE, 0600));
@@ -440,3 +486,55 @@ TEST(TestFile, Tests)
   rv = base->Remove(true);
   VerifyResult(rv, "Cleaning up temp directory");
 }
+
+TEST(TestFile, Unprefixed)
+{
+#ifdef XP_WIN
+  gTestWithPrefix_Win = false;
+#endif
+
+  SetupAndTestFunctions(NS_LITERAL_STRING("mozfiletests"),
+                        /* aTestCreateUnique */ true,
+                        /* aTestNormalize */ true);
+
+#ifdef XP_WIN
+  gTestWithPrefix_Win = true;
+#endif
+}
+
+// This simulates what QM_NewLocalFile does (NS_NewLocalFiles and then
+// SetUseDOSDevicePathSyntax if it's on Windows for NewFile)
+TEST(TestFile, PrefixedOnWin)
+{
+  SetupAndTestFunctions(NS_LITERAL_STRING("mozfiletests"),
+                        /* aTestCreateUnique */ true,
+                        /* aTestNormalize */ true);
+}
+
+TEST(TestFile, PrefixedOnWin_PathExceedsMaxPath)
+{
+  // We want to verify if the prefix would allow as to create a file with over
+  // 260 char for its path. However, on Windows, the maximum length of filename
+  // is 255. Given the base file path and we are going append some other file
+  // to the current base file, let's assume the file path will exceed 260 so
+  // that we are able to verify if the prefix works or not.
+  nsString dirName;
+  dirName.AssignLiteral("mozfiletests");
+  for (uint32_t i = 255 - dirName.Length(); i > 0; --i) {
+    dirName.AppendLiteral("a");
+  }
+
+  // Bypass the test for CreateUnique because there is a check for the max
+  // length of the root on all platforms.
+  SetupAndTestFunctions(dirName, /* aTestCreateUnique */ false,
+                        /* aTestNormalize */ true);
+}
+
+TEST(TestFile, PrefixedOnWin_ComponentEndsWithPeriod)
+{
+  // Bypass the normalization for this because it would strip the trailing
+  // period.
+  SetupAndTestFunctions(NS_LITERAL_STRING("mozfiletests."),
+                        /* aTestCreateUnique */ true,
+                        /* aTestNormalize */ false);
+}
diff --git a/xpcom/tests/gtest/TestFilePreferencesWin.cpp b/xpcom/tests/gtest/TestFilePreferencesWin.cpp
index e11126bba4..16ad5a037b 100644
--- a/xpcom/tests/gtest/TestFilePreferencesWin.cpp
+++ b/xpcom/tests/gtest/TestFilePreferencesWin.cpp
@@ -140,3 +140,65 @@ TEST(FilePreferencesWin, AccessUNC)
   rv = lf->InitWithPath(NS_LITERAL_STRING("\\\\nice\\..\\evil\\share"));
   ASSERT_EQ(rv, NS_ERROR_FILE_ACCESS_DENIED);
 }
+
+TEST(FilePreferencesWin, AccessDOSDevicePath)
+{
+  const auto devicePathSpecifier = NS_LITERAL_STRING("\\\\?\\");
+
+  nsCOMPtr<nsIFile> lf = do_CreateInstance(NS_LOCAL_FILE_CONTRACTID);
+
+  nsresult rv;
+
+  mozilla::FilePreferences::testing::SetBlockUNCPaths(true);
+
+  rv = lf->InitWithPath(devicePathSpecifier +
+                        NS_LITERAL_STRING("evil\\z:\\share"));
+  ASSERT_EQ(rv, NS_ERROR_FILE_ACCESS_DENIED);
+
+  rv = lf->InitWithPath(devicePathSpecifier +
+                        NS_LITERAL_STRING("UNC\\evil\\share"));
+  ASSERT_EQ(rv, NS_ERROR_FILE_ACCESS_DENIED);
+
+  rv = lf->InitWithPath(devicePathSpecifier + NS_LITERAL_STRING("C:\\"));
+  ASSERT_EQ(rv, NS_OK);
+
+  nsCOMPtr<nsIFile> base;
+  rv = NS_GetSpecialDirectory(NS_OS_TEMP_DIR, getter_AddRefs(base));
+  ASSERT_EQ(rv, NS_OK);
+
+  nsAutoString path;
+  rv = base->GetPath(path);
+  ASSERT_EQ(rv, NS_OK);
+
+  rv = lf->InitWithPath(devicePathSpecifier + path);
+  ASSERT_EQ(rv, NS_OK);
+}
+
+TEST(FilePreferencesWin, StartsWithDiskDesignatorAndBackslash)
+{
+  bool result;
+
+  result = mozilla::FilePreferences::StartsWithDiskDesignatorAndBackslash(
+      NS_LITERAL_STRING("\\\\UNC\\path"));
+  ASSERT_FALSE(result);
+
+  result = mozilla::FilePreferences::StartsWithDiskDesignatorAndBackslash(
+      NS_LITERAL_STRING("\\single\\backslash"));
+  ASSERT_FALSE(result);
+
+  result = mozilla::FilePreferences::StartsWithDiskDesignatorAndBackslash(
+      NS_LITERAL_STRING("C:relative"));
+  ASSERT_FALSE(result);
+
+  result = mozilla::FilePreferences::StartsWithDiskDesignatorAndBackslash(
+      NS_LITERAL_STRING("\\\\?\\C:\\"));
+  ASSERT_FALSE(result);
+
+  result = mozilla::FilePreferences::StartsWithDiskDesignatorAndBackslash(
+      NS_LITERAL_STRING("C:\\"));
+  ASSERT_TRUE(result);
+
+  result = mozilla::FilePreferences::StartsWithDiskDesignatorAndBackslash(
+      NS_LITERAL_STRING("c:\\"));
+  ASSERT_TRUE(result);
+}
diff --git a/xpcom/tests/gtest/TestNsDeque.cpp b/xpcom/tests/gtest/TestNsDeque.cpp
index d4a39bfd76..ef043944ef 100644
--- a/xpcom/tests/gtest/TestNsDeque.cpp
+++ b/xpcom/tests/gtest/TestNsDeque.cpp
@@ -8,8 +8,8 @@
 #include "mozilla/TypeTraits.h"
 #include <stdio.h>
 #include <functional>
+#include <utility>
 
-using mozilla::DeclVal;
 using mozilla::IsSame;
 
 /**************************************************************
@@ -344,10 +344,10 @@ TEST(NsDeque, TestConstRangeFor)
   }
 
   static_assert(IsSame<nsDeque::ConstDequeIterator,
-                       decltype(DeclVal<const nsDeque&>().begin())>::value,
+                       decltype(std::declval<const nsDeque&>().begin())>::value,
                 "(const nsDeque).begin() should return ConstDequeIterator");
   static_assert(IsSame<nsDeque::ConstDequeIterator,
-                       decltype(DeclVal<const nsDeque&>().end())>::value,
+                       decltype(std::declval<const nsDeque&>().end())>::value,
                 "(const nsDeque).end() should return ConstDequeIterator");
 
   int sum = 0;
diff --git a/xpcom/tests/gtest/TestObserverArray.cpp b/xpcom/tests/gtest/TestObserverArray.cpp
index fa503d85d0..4a8b95c82b 100644
--- a/xpcom/tests/gtest/TestObserverArray.cpp
+++ b/xpcom/tests/gtest/TestObserverArray.cpp
@@ -5,6 +5,7 @@
 #include "nsTObserverArray.h"
 #include "gtest/gtest.h"
 #include "mozilla/ArrayUtils.h"
+#include "mozilla/UniquePtr.h"
 
 using namespace mozilla;
 
@@ -152,3 +153,398 @@ TEST(ObserverArray, Tests)
    * In that case BackwardIterator does not traverse the newly prepended Element
    */
 }
+
+TEST(ObserverArray, RangeBasedFor_Value_Forward_NonEmpty)
+{
+  IntArray arr;
+  arr.AppendElement(3);
+  arr.AppendElement(4);
+
+  size_t iterations = 0;
+  int sum = 0;
+  for (int element : arr.ForwardRange()) {
+    sum += element;
+    ++iterations;
+  }
+
+  EXPECT_EQ(2u, iterations);
+  EXPECT_EQ(7, sum);
+}
+
+TEST(ObserverArray, RangeBasedFor_Value_Forward_RemoveCurrent)
+{
+  IntArray arr;
+  arr.AppendElement(3);
+  arr.AppendElement(4);
+
+  size_t iterations = 0;
+  int sum = 0;
+  for (int element : arr.ForwardRange()) {
+    sum += element;
+    ++iterations;
+    arr.RemoveElementAt(0);
+  }
+
+  EXPECT_EQ(2u, iterations);
+  EXPECT_EQ(7, sum);
+}
+
+TEST(ObserverArray, RangeBasedFor_Value_Forward_Append)
+{
+  IntArray arr;
+  arr.AppendElement(3);
+  arr.AppendElement(4);
+
+  size_t iterations = 0;
+  int sum = 0;
+  for (int element : arr.ForwardRange()) {
+    if (!iterations) {
+      arr.AppendElement(5);
+    }
+    sum += element;
+    ++iterations;
+  }
+
+  EXPECT_EQ(3u, iterations);
+  EXPECT_EQ(12, sum);
+}
+
+TEST(ObserverArray, RangeBasedFor_Value_Forward_Prepend)
+{
+  IntArray arr;
+  arr.AppendElement(3);
+  arr.AppendElement(4);
+
+  size_t iterations = 0;
+  int sum = 0;
+  for (int element : arr.ForwardRange()) {
+    if (!iterations) {
+      arr.InsertElementAt(0, 5);
+    }
+    sum += element;
+    ++iterations;
+  }
+
+  EXPECT_EQ(2u, iterations);
+  EXPECT_EQ(7, sum);
+}
+
+TEST(ObserverArray, RangeBasedFor_Value_Forward_Empty)
+{
+  IntArray arr;
+
+  size_t iterations = 0;
+  for (int element : arr.ForwardRange()) {
+    (void)element;
+    ++iterations;
+  }
+
+  EXPECT_EQ(0u, iterations);
+}
+
+TEST(ObserverArray, RangeBasedFor_Reference_Forward_NonEmpty)
+{
+  const auto arr = [] {
+    nsTObserverArray<UniquePtr<int>> arr;
+    arr.AppendElement(MakeUnique<int>(3));
+    arr.AppendElement(MakeUnique<int>(4));
+    return arr;
+  }();
+
+  size_t iterations = 0;
+  int sum = 0;
+  for (const UniquePtr<int>& element : arr.ForwardRange()) {
+    sum += *element;
+    ++iterations;
+  }
+
+  EXPECT_EQ(2u, iterations);
+  EXPECT_EQ(7, sum);
+}
+
+TEST(ObserverArray, RangeBasedFor_NonConstReference_Forward_NonEmpty)
+{
+  nsTObserverArray<UniquePtr<int>> arr;
+  arr.AppendElement(MakeUnique<int>(3));
+  arr.AppendElement(MakeUnique<int>(4));
+
+  size_t iterations = 0;
+  int sum = 0;
+  for (UniquePtr<int>& element : arr.ForwardRange()) {
+    sum += *element;
+    ++iterations;
+  }
+
+  EXPECT_EQ(2u, iterations);
+  EXPECT_EQ(7, sum);
+}
+
+TEST(ObserverArray, RangeBasedFor_Value_Backward_NonEmpty)
+{
+  IntArray arr;
+  arr.AppendElement(3);
+  arr.AppendElement(4);
+
+  size_t iterations = 0;
+  int sum = 0;
+  for (int element : arr.BackwardRange()) {
+    sum += element;
+    ++iterations;
+  }
+
+  EXPECT_EQ(2u, iterations);
+  EXPECT_EQ(7, sum);
+}
+
+TEST(ObserverArray, RangeBasedFor_Value_Backward_RemoveCurrent)
+{
+  IntArray arr;
+  arr.AppendElement(3);
+  arr.AppendElement(4);
+
+  size_t iterations = 0;
+  int sum = 0;
+  for (int element : arr.BackwardRange()) {
+    sum += element;
+    ++iterations;
+    arr.RemoveElementAt(arr.Length() - 1);
+  }
+
+  EXPECT_EQ(2u, iterations);
+  EXPECT_EQ(7, sum);
+}
+
+TEST(ObserverArray, RangeBasedFor_Value_Backward_Append)
+{
+  IntArray arr;
+  arr.AppendElement(3);
+  arr.AppendElement(4);
+
+  size_t iterations = 0;
+  int sum = 0;
+  for (int element : arr.BackwardRange()) {
+    if (!iterations) {
+      arr.AppendElement(5);
+    }
+    sum += element;
+    ++iterations;
+  }
+
+  EXPECT_EQ(2u, iterations);
+  EXPECT_EQ(7, sum);
+}
+
+TEST(ObserverArray, RangeBasedFor_Value_Backward_Prepend)
+{
+  IntArray arr;
+  arr.AppendElement(3);
+  arr.AppendElement(4);
+
+  size_t iterations = 0;
+  int sum = 0;
+  for (int element : arr.BackwardRange()) {
+    if (!iterations) {
+      arr.InsertElementAt(0, 5);
+    }
+    sum += element;
+    ++iterations;
+  }
+
+  EXPECT_EQ(3u, iterations);
+  EXPECT_EQ(12, sum);
+}
+
+TEST(ObserverArray, RangeBasedFor_Value_Backward_Empty)
+{
+  IntArray arr;
+
+  size_t iterations = 0;
+  for (int element : arr.BackwardRange()) {
+    (void)element;
+    ++iterations;
+  }
+
+  EXPECT_EQ(0u, iterations);
+}
+
+TEST(ObserverArray, RangeBasedFor_Reference_Backward_NonEmpty)
+{
+  const auto arr = [] {
+    nsTObserverArray<UniquePtr<int>> arr;
+    arr.AppendElement(MakeUnique<int>(3));
+    arr.AppendElement(MakeUnique<int>(4));
+    return arr;
+  }();
+
+  size_t iterations = 0;
+  int sum = 0;
+  for (const UniquePtr<int>& element : arr.BackwardRange()) {
+    sum += *element;
+    ++iterations;
+  }
+
+  EXPECT_EQ(2u, iterations);
+  EXPECT_EQ(7, sum);
+}
+
+TEST(ObserverArray, RangeBasedFor_NonConstReference_Backward_NonEmpty)
+{
+  nsTObserverArray<UniquePtr<int>> arr;
+  arr.AppendElement(MakeUnique<int>(3));
+  arr.AppendElement(MakeUnique<int>(4));
+
+  size_t iterations = 0;
+  int sum = 0;
+  for (UniquePtr<int>& element : arr.BackwardRange()) {
+    sum += *element;
+    ++iterations;
+  }
+
+  EXPECT_EQ(2u, iterations);
+  EXPECT_EQ(7, sum);
+}
+
+TEST(ObserverArray, RangeBasedFor_Value_EndLimited_NonEmpty)
+{
+  IntArray arr;
+  arr.AppendElement(3);
+  arr.AppendElement(4);
+
+  size_t iterations = 0;
+  int sum = 0;
+  for (int element : arr.EndLimitedRange()) {
+    sum += element;
+    ++iterations;
+  }
+
+  EXPECT_EQ(2u, iterations);
+  EXPECT_EQ(7, sum);
+}
+
+TEST(ObserverArray, RangeBasedFor_Value_EndLimited_RemoveCurrent)
+{
+  IntArray arr;
+  arr.AppendElement(3);
+  arr.AppendElement(4);
+
+  size_t iterations = 0;
+  int sum = 0;
+  for (int element : arr.EndLimitedRange()) {
+    sum += element;
+    ++iterations;
+    arr.RemoveElementAt(0);
+  }
+
+  EXPECT_EQ(2u, iterations);
+  EXPECT_EQ(7, sum);
+}
+
+TEST(ObserverArray, RangeBasedFor_Value_EndLimited_Append)
+{
+  IntArray arr;
+  arr.AppendElement(3);
+  arr.AppendElement(4);
+
+  size_t iterations = 0;
+  int sum = 0;
+  for (int element : arr.EndLimitedRange()) {
+    if (!iterations) {
+      arr.AppendElement(5);
+    }
+    sum += element;
+    ++iterations;
+  }
+
+  EXPECT_EQ(2u, iterations);
+  EXPECT_EQ(7, sum);
+}
+
+TEST(ObserverArray, RangeBasedFor_Value_EndLimited_Prepend)
+{
+  IntArray arr;
+  arr.AppendElement(3);
+  arr.AppendElement(4);
+
+  size_t iterations = 0;
+  int sum = 0;
+  for (int element : arr.EndLimitedRange()) {
+    if (!iterations) {
+      arr.InsertElementAt(0, 5);
+    }
+    sum += element;
+    ++iterations;
+  }
+
+  EXPECT_EQ(2u, iterations);
+  EXPECT_EQ(7, sum);
+}
+
+TEST(ObserverArray, RangeBasedFor_Value_EndLimited_Empty)
+{
+  IntArray arr;
+
+  size_t iterations = 0;
+  for (int element : arr.EndLimitedRange()) {
+    (void)element;
+    ++iterations;
+  }
+
+  EXPECT_EQ(0u, iterations);
+}
+
+TEST(ObserverArray, RangeBasedFor_Reference_EndLimited_NonEmpty)
+{
+  const auto arr = [] {
+    nsTObserverArray<UniquePtr<int>> arr;
+    arr.AppendElement(MakeUnique<int>(3));
+    arr.AppendElement(MakeUnique<int>(4));
+    return arr;
+  }();
+
+  size_t iterations = 0;
+  int sum = 0;
+  for (const UniquePtr<int>& element : arr.EndLimitedRange()) {
+    sum += *element;
+    ++iterations;
+  }
+
+  EXPECT_EQ(2u, iterations);
+  EXPECT_EQ(7, sum);
+}
+
+TEST(ObserverArray, RangeBasedFor_NonConstReference_EndLimited_NonEmpty)
+{
+  nsTObserverArray<UniquePtr<int>> arr;
+  arr.AppendElement(MakeUnique<int>(3));
+  arr.AppendElement(MakeUnique<int>(4));
+
+  size_t iterations = 0;
+  int sum = 0;
+  for (UniquePtr<int>& element : arr.EndLimitedRange()) {
+    sum += *element;
+    ++iterations;
+  }
+
+  EXPECT_EQ(2u, iterations);
+  EXPECT_EQ(7, sum);
+}
+
+TEST(ObserverArray, RangeBasedFor_Reference_NonObserving_NonEmpty)
+{
+  const auto arr = [] {
+    nsTObserverArray<UniquePtr<int>> arr;
+    arr.AppendElement(MakeUnique<int>(3));
+    arr.AppendElement(MakeUnique<int>(4));
+    return arr;
+  }();
+
+  size_t iterations = 0;
+  int sum = 0;
+  for (const UniquePtr<int>& element : arr.NonObservingRange()) {
+    sum += *element;
+    ++iterations;
+  }
+
+  EXPECT_EQ(2u, iterations);
+  EXPECT_EQ(7, sum);
+}
diff --git a/xpcom/tests/gtest/TestRacingServiceManager.cpp b/xpcom/tests/gtest/TestRacingServiceManager.cpp
index 2d30f66572..c914755ab8 100644
--- a/xpcom/tests/gtest/TestRacingServiceManager.cpp
+++ b/xpcom/tests/gtest/TestRacingServiceManager.cpp
@@ -7,7 +7,6 @@
 #include "nsXULAppAPI.h"
 #include "nsIThread.h"
 
-#include "nsAutoPtr.h"
 #include "nsThreadUtils.h"
 #include "nsXPCOMCIDInternal.h"
 #include "pratom.h"
diff --git a/xpcom/tests/gtest/TestTArray2.cpp b/xpcom/tests/gtest/TestTArray2.cpp
index a66d0e2aaf..c0f575801a 100644
--- a/xpcom/tests/gtest/TestTArray2.cpp
+++ b/xpcom/tests/gtest/TestTArray2.cpp
@@ -9,7 +9,6 @@
 #include <stdio.h>
 #include <iostream>
 #include "nsTArray.h"
-#include "nsAutoPtr.h"
 #include "nsString.h"
 #include "nsDirectoryServiceDefs.h"
 #include "nsDirectoryServiceUtils.h"
diff --git a/xpcom/tests/gtest/moz.build b/xpcom/tests/gtest/moz.build
index cda7705015..0cd4b03c3f 100644
--- a/xpcom/tests/gtest/moz.build
+++ b/xpcom/tests/gtest/moz.build
@@ -5,6 +5,7 @@
 UNIFIED_SOURCES += [
     'Helpers.cpp',
     'TestArenaAllocator.cpp',
+    'TestArrayAlgorithm.cpp',
     'TestAtoms.cpp',
     'TestAutoPtr.cpp',
     'TestAutoRef.cpp',
diff --git a/xpcom/threads/AbstractEventQueue.h b/xpcom/threads/AbstractEventQueue.h
index 646297b2d2..7658145c30 100644
--- a/xpcom/threads/AbstractEventQueue.h
+++ b/xpcom/threads/AbstractEventQueue.h
@@ -8,6 +8,7 @@
 #include "base/lock.h"
 #include "mozilla/AlreadyAddRefed.h"
 #include "mozilla/MemoryReporting.h"
+#include "mozilla/TimeStamp.h"
 
 class nsIRunnable;
 
@@ -42,19 +43,26 @@ enum class EventQueuePriority {
 class AbstractEventQueue {
  public:
   // Add an event to the end of the queue. Implementors are free to use
-  // aPriority however they wish.  If the runnable supports nsIRunnablePriority
-  // and the implementing class supports prioritization, aPriority represents
-  // the result of calling nsIRunnablePriority::GetPriority().
+  // aPriority however they wish.  If the runnable supports
+  // nsIRunnablePriority and the implementing class supports
+  // prioritization, aPriority represents the result of calling
+  // nsIRunnablePriority::GetPriority().  *aDelay is time the event has
+  // already been delayed (used when moving an event from one queue to
+  // another)
   virtual void PutEvent(already_AddRefed<nsIRunnable>&& aEvent,
                         EventQueuePriority aPriority,
-                        const AutoLock& aProofOfLock) = 0;
+                        const AutoLock& aProofOfLock,
+                        mozilla::TimeDuration* aDelay = nullptr) = 0;
 
   // Get an event from the front of the queue. aPriority is an out param. If the
   // implementation supports priorities, then this should be the same priority
   // that the event was pushed with. aPriority may be null. This should return
   // null if the queue is non-empty but the event in front is not ready to run.
+  // *aLastEventDelay is the time the event spent in queues before being
+  // retrieved.
   virtual already_AddRefed<nsIRunnable> GetEvent(
-      EventQueuePriority* aPriority, const AutoLock& aProofOfLock) = 0;
+      EventQueuePriority* aPriority, const AutoLock& aProofOfLock,
+      mozilla::TimeDuration* aLastEventDelay = nullptr) = 0;
 
   // Returns true if the queue is empty. Implies !HasReadyEvent().
   virtual bool IsEmpty(const AutoLock& aProofOfLock) = 0;
diff --git a/xpcom/threads/BlockingResourceBase.cpp b/xpcom/threads/BlockingResourceBase.cpp
index b4a802d5ea..d55211f16d 100644
--- a/xpcom/threads/BlockingResourceBase.cpp
+++ b/xpcom/threads/BlockingResourceBase.cpp
@@ -7,8 +7,6 @@
 #ifdef DEBUG
 #  include "prthread.h"
 
-#  include "nsAutoPtr.h"
-
 #  ifndef MOZ_CALLSTACK_DISABLED
 #    include "CodeAddressService.h"
 #    include "nsHashKeys.h"
@@ -22,6 +20,7 @@
 #  include "mozilla/ReentrantMonitor.h"
 #  include "mozilla/Mutex.h"
 #  include "mozilla/RWLock.h"
+#  include "mozilla/UniquePtr.h"
 
 #  if defined(MOZILLA_INTERNAL_API)
 #    include "GeckoProfiler.h"
@@ -87,9 +86,9 @@ void BlockingResourceBase::GetStackTrace(AcquisitionState& aState) {
  * some info is written into |aOut|
  */
 static bool PrintCycle(
-    const BlockingResourceBase::DDT::ResourceAcquisitionArray* aCycle,
+    const BlockingResourceBase::DDT::ResourceAcquisitionArray& aCycle,
     nsACString& aOut) {
-  NS_ASSERTION(aCycle->Length() > 1, "need > 1 element for cycle!");
+  NS_ASSERTION(aCycle.Length() > 1, "need > 1 element for cycle!");
 
   bool maybeImminent = true;
 
@@ -97,14 +96,14 @@ static bool PrintCycle(
   aOut += "Cyclical dependency starts at\n";
 
   const BlockingResourceBase::DDT::ResourceAcquisitionArray::elem_type res =
-      aCycle->ElementAt(0);
+      aCycle.ElementAt(0);
   maybeImminent &= res->Print(aOut);
 
   BlockingResourceBase::DDT::ResourceAcquisitionArray::index_type i;
   BlockingResourceBase::DDT::ResourceAcquisitionArray::size_type len =
-      aCycle->Length();
+      aCycle.Length();
   const BlockingResourceBase::DDT::ResourceAcquisitionArray::elem_type* it =
-      1 + aCycle->Elements();
+      1 + aCycle.Elements();
   for (i = 1; i < len - 1; ++i, ++it) {
     fputs("\n--- Next dependency:\n", stderr);
     aOut += "\nNext dependency:\n";
@@ -119,42 +118,6 @@ static bool PrintCycle(
   return maybeImminent;
 }
 
-#  ifndef MOZ_CALLSTACK_DISABLED
-struct CodeAddressServiceLock final {
-  static void Unlock() {}
-  static void Lock() {}
-  static bool IsLocked() { return true; }
-};
-
-struct CodeAddressServiceStringAlloc final {
-  static char* copy(const char* aString) { return ::strdup(aString); }
-  static void free(char* aString) { ::free(aString); }
-};
-
-class CodeAddressServiceStringTable final {
- public:
-  CodeAddressServiceStringTable() : mSet(32) {}
-
-  const char* Intern(const char* aString) {
-    nsCharPtrHashKey* e = mSet.PutEntry(aString);
-    return e->GetKey();
-  }
-
-  size_t SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const {
-    return mSet.SizeOfExcludingThis(aMallocSizeOf);
-  }
-
- private:
-  typedef nsTHashtable<nsCharPtrHashKey> StringSet;
-  StringSet mSet;
-};
-
-typedef CodeAddressService<CodeAddressServiceStringTable,
-                           CodeAddressServiceStringAlloc,
-                           CodeAddressServiceLock>
-    WalkTheStackCodeAddressService;
-#  endif
-
 bool BlockingResourceBase::Print(nsACString& aOut) const {
   fprintf(stderr, "--- %s : %s", kResourceTypeName[mType], mName);
   aOut += BlockingResourceBase::kResourceTypeName[mType];
@@ -174,7 +137,7 @@ bool BlockingResourceBase::Print(nsACString& aOut) const {
 #  else
   const AcquisitionState& state = acquired ? mAcquired : mFirstSeen;
 
-  WalkTheStackCodeAddressService addressService;
+  CodeAddressService<> addressService;
 
   for (uint32_t i = 0; i < state.ref().Length(); i++) {
     const size_t kMaxLength = 1024;
@@ -255,7 +218,7 @@ void BlockingResourceBase::CheckAcquire() {
   }
 
   BlockingResourceBase* chainFront = ResourceChainFront();
-  nsAutoPtr<DDT::ResourceAcquisitionArray> cycle(
+  mozilla::UniquePtr<DDT::ResourceAcquisitionArray> cycle(
       sDeadlockDetector->CheckAcquisition(chainFront ? chainFront : 0, this));
   if (!cycle) {
     return;
@@ -268,7 +231,7 @@ void BlockingResourceBase::CheckAcquire() {
 
   fputs("###!!! ERROR: Potential deadlock detected:\n", stderr);
   nsAutoCString out("Potential deadlock detected:\n");
-  bool maybeImminent = PrintCycle(cycle, out);
+  bool maybeImminent = PrintCycle(*cycle, out);
 
   if (maybeImminent) {
     fputs("\n###!!! Deadlock may happen NOW!\n\n", stderr);
diff --git a/xpcom/threads/EventQueue.cpp b/xpcom/threads/EventQueue.cpp
index 5ca5269c64..a58857becd 100644
--- a/xpcom/threads/EventQueue.cpp
+++ b/xpcom/threads/EventQueue.cpp
@@ -6,19 +6,39 @@
 #include "nsIRunnable.h"
 
 using namespace mozilla;
+using namespace mozilla::detail;
 
-EventQueue::EventQueue(EventQueuePriority aPriority) {}
+template <size_t ItemsPerPage>
+EventQueueInternal<ItemsPerPage>::EventQueueInternal(
+    EventQueuePriority aPriority) {}
+
+template <size_t ItemsPerPage>
+void EventQueueInternal<ItemsPerPage>::PutEvent(
+    already_AddRefed<nsIRunnable>&& aEvent, EventQueuePriority aPriority,
+    const AutoLock& aProofOfLock, mozilla::TimeDuration* aDelay) {
+#ifdef MOZ_GECKO_PROFILER
+  // Sigh, this doesn't check if this thread is being profiled
+  if (profiler_is_active()) {
+    // check to see if the profiler has been enabled since the last PutEvent
+    while (mDispatchTimes.Count() < mQueue.Count()) {
+      mDispatchTimes.Push(TimeStamp());
+    }
+    mDispatchTimes.Push(aDelay ? TimeStamp::Now() - *aDelay : TimeStamp::Now());
+  }
+#endif
 
-void EventQueue::PutEvent(already_AddRefed<nsIRunnable>&& aEvent,
-                          EventQueuePriority aPriority,
-                          const AutoLock& aProofOfLock) {
   nsCOMPtr<nsIRunnable> event(aEvent);
   mQueue.Push(std::move(event));
 }
 
-already_AddRefed<nsIRunnable> EventQueue::GetEvent(
-    EventQueuePriority* aPriority, const AutoLock& aProofOfLock) {
+template <size_t ItemsPerPage>
+already_AddRefed<nsIRunnable> EventQueueInternal<ItemsPerPage>::GetEvent(
+    EventQueuePriority* aPriority, const AutoLock& aProofOfLock,
+    mozilla::TimeDuration* aLastEventDelay) {
   if (mQueue.IsEmpty()) {
+    if (aLastEventDelay) {
+      *aLastEventDelay = TimeDuration();
+    }
     return nullptr;
   }
 
@@ -26,28 +46,47 @@ already_AddRefed<nsIRunnable> EventQueue::GetEvent(
     *aPriority = EventQueuePriority::Normal;
   }
 
+#ifdef MOZ_GECKO_PROFILER
+  // We always want to clear the dispatch times, even if the profiler is turned
+  // off, because we want to empty the (previously-collected) dispatch times, if
+  // any, from when the profiler was turned on.  We only want to do something
+  // interesting with the dispatch times if the profiler is turned on, though.
+  if (!mDispatchTimes.IsEmpty()) {
+    TimeStamp dispatch_time = mDispatchTimes.Pop();
+    if (profiler_is_active()) {
+      if (!dispatch_time.IsNull()) {
+        if (aLastEventDelay) {
+          *aLastEventDelay = TimeStamp::Now() - dispatch_time;
+        }
+      }
+    }
+  } else if (profiler_is_active()) {
+    if (aLastEventDelay) {
+      // if we just turned on the profiler, we don't have dispatch
+      // times for events already in the queue.
+      *aLastEventDelay = TimeDuration();
+    }
+  }
+#endif
+
   nsCOMPtr<nsIRunnable> result = mQueue.Pop();
   return result.forget();
 }
 
-bool EventQueue::IsEmpty(const AutoLock& aProofOfLock) {
+template <size_t ItemsPerPage>
+bool EventQueueInternal<ItemsPerPage>::IsEmpty(
+    const AutoLock& aProofOfLock) {
   return mQueue.IsEmpty();
 }
 
-bool EventQueue::HasReadyEvent(const AutoLock& aProofOfLock) {
+template <size_t ItemsPerPage>
+bool EventQueueInternal<ItemsPerPage>::HasReadyEvent(
+    const AutoLock& aProofOfLock) {
   return !IsEmpty(aProofOfLock);
 }
 
-already_AddRefed<nsIRunnable> EventQueue::PeekEvent(
-    const AutoLock& aProofOfLock) {
-  if (mQueue.IsEmpty()) {
-    return nullptr;
-  }
-
-  nsCOMPtr<nsIRunnable> result = mQueue.FirstElement();
-  return result.forget();
-}
-
-size_t EventQueue::Count(const AutoLock& aProofOfLock) const {
+template <size_t ItemsPerPage>
+size_t EventQueueInternal<ItemsPerPage>::Count(
+    const AutoLock& aProofOfLock) const {
   return mQueue.Count();
 }
diff --git a/xpcom/threads/EventQueue.h b/xpcom/threads/EventQueue.h
index 379d9bcdd0..523576d961 100644
--- a/xpcom/threads/EventQueue.h
+++ b/xpcom/threads/EventQueue.h
@@ -13,28 +13,40 @@ class nsIRunnable;
 
 namespace mozilla {
 
-class EventQueue final : public AbstractEventQueue {
+namespace detail {
+
+template <size_t ItemsPerPage>
+class EventQueueInternal : public AbstractEventQueue {
  public:
   static const bool SupportsPrioritization = false;
 
-  EventQueue() {}
-  explicit EventQueue(EventQueuePriority aPriority);
+  EventQueueInternal() {}
+  explicit EventQueueInternal(EventQueuePriority aPriority);
 
   void PutEvent(already_AddRefed<nsIRunnable>&& aEvent,
-                EventQueuePriority aPriority,
-                const AutoLock& aProofOfLock) final;
+                EventQueuePriority aPriority, const AutoLock& aProofOfLock,
+                mozilla::TimeDuration* aDelay = nullptr) final;
   already_AddRefed<nsIRunnable> GetEvent(
-      EventQueuePriority* aPriority, const AutoLock& aProofOfLock) final;
+      EventQueuePriority* aPriority, const AutoLock& aProofOfLock,
+      mozilla::TimeDuration* aLastEventDelay = nullptr) final;
 
   bool IsEmpty(const AutoLock& aProofOfLock) final;
   bool HasReadyEvent(const AutoLock& aProofOfLock) final;
   bool HasPendingHighPriorityEvents(const AutoLock& aProofOfLock) final {
-    // EventQueue doesn't support any prioritization.
+    // EventQueueInternal doesn't support any prioritization.
     return false;
   }
 
   size_t Count(const AutoLock& aProofOfLock) const final;
-  already_AddRefed<nsIRunnable> PeekEvent(const AutoLock& aProofOfLock);
+  // For some reason, if we put this in the .cpp file the linker can't find it
+  already_AddRefed<nsIRunnable> PeekEvent(const AutoLock& aProofOfLock) {
+    if (mQueue.IsEmpty()) {
+      return nullptr;
+    }
+
+    nsCOMPtr<nsIRunnable> result = mQueue.FirstElement();
+    return result.forget();
+  }
 
   void EnableInputEventPrioritization(const AutoLock& aProofOfLock) final {
   }
@@ -46,11 +58,38 @@ class EventQueue final : public AbstractEventQueue {
 
   size_t SizeOfExcludingThis(
       mozilla::MallocSizeOf aMallocSizeOf) const override {
-    return mQueue.ShallowSizeOfExcludingThis(aMallocSizeOf);
+    size_t size = mQueue.ShallowSizeOfExcludingThis(aMallocSizeOf);
+#ifdef MOZ_GECKO_PROFILER
+    size += mDispatchTimes.ShallowSizeOfExcludingThis(aMallocSizeOf);
+#endif
+    return size;
   }
 
  private:
-  mozilla::Queue<nsCOMPtr<nsIRunnable>> mQueue;
+  mozilla::Queue<nsCOMPtr<nsIRunnable>, ItemsPerPage> mQueue;
+#ifdef MOZ_GECKO_PROFILER
+  // This queue is only populated when the profiler is turned on.
+  mozilla::Queue<mozilla::TimeStamp, ItemsPerPage> mDispatchTimes;
+  TimeDuration mLastEventDelay;
+#endif
+};
+
+}  // namespace detail
+
+class EventQueue final : public mozilla::detail::EventQueueInternal<16> {
+ public:
+  EventQueue() : mozilla::detail::EventQueueInternal<16>() {}
+  explicit EventQueue(EventQueuePriority aPriority)
+      : mozilla::detail::EventQueueInternal<16>(aPriority){};
+};
+
+template <size_t ItemsPerPage = 16>
+class EventQueueSized final
+    : public mozilla::detail::EventQueueInternal<ItemsPerPage> {
+ public:
+  EventQueueSized() : mozilla::detail::EventQueueInternal<ItemsPerPage>() {}
+  explicit EventQueueSized(EventQueuePriority aPriority)
+      : mozilla::detail::EventQueueInternal<ItemsPerPage>(aPriority){};
 };
 
 }  // namespace mozilla
diff --git a/xpcom/threads/LazyIdleThread.cpp b/xpcom/threads/LazyIdleThread.cpp
index 08a57a3e76..8410fa07e9 100644
--- a/xpcom/threads/LazyIdleThread.cpp
+++ b/xpcom/threads/LazyIdleThread.cpp
@@ -392,6 +392,24 @@ LazyIdleThread::DelayedDispatch(already_AddRefed<nsIRunnable>, uint32_t) {
   return NS_ERROR_NOT_IMPLEMENTED;
 }
 
+NS_IMETHODIMP
+LazyIdleThread::GetRunningEventDelay(TimeDuration* aDelay, TimeStamp* aStart) {
+  if (mThread) {
+    return mThread->GetRunningEventDelay(aDelay, aStart);
+  }
+  *aDelay = TimeDuration();
+  *aStart = TimeStamp();
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+LazyIdleThread::SetRunningEventDelay(TimeDuration aDelay, TimeStamp aStart) {
+  if (mThread) {
+    return mThread->SetRunningEventDelay(aDelay, aStart);
+  }
+  return NS_OK;
+}
+
 NS_IMETHODIMP
 LazyIdleThread::IsOnCurrentThread(bool* aIsOnCurrentThread) {
   if (mThread) {
diff --git a/xpcom/threads/MainThreadQueue.h b/xpcom/threads/MainThreadQueue.h
index e1e4db78c9..82bf8dd896 100644
--- a/xpcom/threads/MainThreadQueue.h
+++ b/xpcom/threads/MainThreadQueue.h
@@ -33,10 +33,6 @@ inline already_AddRefed<nsThread> CreateMainThread(
   RefPtr<nsThread> mainThread =
       new nsThread(WrapNotNull(synchronizedQueue), nsThread::MAIN_THREAD, 0);
 
-#ifndef RELEASE_OR_BETA
-  prioritized->SetNextIdleDeadlineRef(mainThread->NextIdleDeadlineRef());
-#endif
-
   if (aSynchronizedQueue) {
     synchronizedQueue.forget(aSynchronizedQueue);
   }
diff --git a/xpcom/threads/MozPromise.h b/xpcom/threads/MozPromise.h
index bf0b30443e..c7e3a43042 100644
--- a/xpcom/threads/MozPromise.h
+++ b/xpcom/threads/MozPromise.h
@@ -6,6 +6,7 @@
 #  define MozPromise_h_
 
 #  include <type_traits>
+#  include <utility>
 
 #  include "mozilla/Logging.h"
 #  include "mozilla/Maybe.h"
@@ -13,6 +14,7 @@
 #  include "mozilla/RefPtr.h"
 #  include "mozilla/Tuple.h"
 #  include "mozilla/TypeTraits.h"
+#  include "mozilla/UniquePtr.h"
 #  include "mozilla/Variant.h"
 
 #  include "nsISerialEventTarget.h"
@@ -62,7 +64,7 @@ struct MethodTraitsHelper<Ret (ThisType::*)(ArgTypes...) const volatile> {
   static const size_t ArgSize = sizeof...(ArgTypes);
 };
 template <typename T>
-struct MethodTrait : MethodTraitsHelper<typename RemoveReference<T>::Type> {};
+struct MethodTrait : MethodTraitsHelper<std::remove_reference_t<T>> {};
 
 }  // namespace detail
 
@@ -72,8 +74,8 @@ using TakesArgument =
 
 template <typename MethodType, typename TargetType>
 using ReturnTypeIs =
-    IsConvertible<typename detail::MethodTrait<MethodType>::ReturnType,
-                  TargetType>;
+    std::is_convertible<typename detail::MethodTrait<MethodType>::ReturnType,
+                        TargetType>;
 
 template <typename ResolveValueT, typename RejectValueT, bool IsExclusive>
 class MozPromise;
@@ -154,7 +156,7 @@ class MozPromise : public MozPromiseBase {
   // Return a |T&&| to enable move when IsExclusive is true or
   // a |const T&| to enforce copy otherwise.
   template <typename T,
-            typename R = typename Conditional<IsExclusive, T&&, const T&>::Type>
+            typename R = std::conditional_t<IsExclusive, T&&, const T&>>
   static R MaybeMove(T& aX) {
     return static_cast<R>(aX);
   }
@@ -241,35 +243,35 @@ class MozPromise : public MozPromiseBase {
   class Private;
 
   template <typename ResolveValueType_>
-  static RefPtr<MozPromise> CreateAndResolve(ResolveValueType_&& aResolveValue,
-                                             const char* aResolveSite) {
-    static_assert(IsConvertible<ResolveValueType_, ResolveValueT>::value,
+  [[nodiscard]] static RefPtr<MozPromise> CreateAndResolve(
+      ResolveValueType_&& aResolveValue, const char* aResolveSite) {
+    static_assert(std::is_convertible_v<ResolveValueType_, ResolveValueT>,
                   "Resolve() argument must be implicitly convertible to "
                   "MozPromise's ResolveValueT");
     RefPtr<typename MozPromise::Private> p =
         new MozPromise::Private(aResolveSite);
     p->Resolve(std::forward<ResolveValueType_>(aResolveValue), aResolveSite);
-    return p.forget();
+    return p;
   }
 
   template <typename RejectValueType_>
-  static RefPtr<MozPromise> CreateAndReject(RejectValueType_&& aRejectValue,
-                                            const char* aRejectSite) {
-    static_assert(IsConvertible<RejectValueType_, RejectValueT>::value,
+  [[nodiscard]] static RefPtr<MozPromise> CreateAndReject(
+      RejectValueType_&& aRejectValue, const char* aRejectSite) {
+    static_assert(std::is_convertible_v<RejectValueType_, RejectValueT>,
                   "Reject() argument must be implicitly convertible to "
                   "MozPromise's RejectValueT");
     RefPtr<typename MozPromise::Private> p =
         new MozPromise::Private(aRejectSite);
     p->Reject(std::forward<RejectValueType_>(aRejectValue), aRejectSite);
-    return p.forget();
+    return p;
   }
 
   template <typename ResolveOrRejectValueType_>
-  static RefPtr<MozPromise> CreateAndResolveOrReject(
+  [[nodiscard]] static RefPtr<MozPromise> CreateAndResolveOrReject(
       ResolveOrRejectValueType_&& aValue, const char* aSite) {
     RefPtr<typename MozPromise::Private> p = new MozPromise::Private(aSite);
     p->ResolveOrReject(std::forward<ResolveOrRejectValueType_>(aValue), aSite);
-    return p.forget();
+    return p;
   }
 
   typedef MozPromise<nsTArray<ResolveValueType>, RejectValueType, IsExclusive>
@@ -325,8 +327,9 @@ class MozPromise : public MozPromiseBase {
   };
 
  public:
-  static RefPtr<AllPromiseType> All(nsISerialEventTarget* aProcessingTarget,
-                                    nsTArray<RefPtr<MozPromise>>& aPromises) {
+  [[nodiscard]] static RefPtr<AllPromiseType> All(
+      nsISerialEventTarget* aProcessingTarget,
+      nsTArray<RefPtr<MozPromise>>& aPromises) {
     if (aPromises.Length() == 0) {
       return AllPromiseType::CreateAndResolve(nsTArray<ResolveValueType>(),
                                               __func__);
@@ -495,17 +498,15 @@ class MozPromise : public MozPromiseBase {
    * make the resolve/reject value argument "optional".
    */
   template <typename ThisType, typename MethodType, typename ValueType>
-  static typename EnableIf<
-      TakesArgument<MethodType>::value,
-      typename detail::MethodTrait<MethodType>::ReturnType>::Type
+  static std::enable_if_t<TakesArgument<MethodType>::value,
+                          typename detail::MethodTrait<MethodType>::ReturnType>
   InvokeMethod(ThisType* aThisVal, MethodType aMethod, ValueType&& aValue) {
     return (aThisVal->*aMethod)(std::forward<ValueType>(aValue));
   }
 
   template <typename ThisType, typename MethodType, typename ValueType>
-  static typename EnableIf<
-      !TakesArgument<MethodType>::value,
-      typename detail::MethodTrait<MethodType>::ReturnType>::Type
+  static std::enable_if_t<!TakesArgument<MethodType>::value,
+                          typename detail::MethodTrait<MethodType>::ReturnType>
   InvokeMethod(ThisType* aThisVal, MethodType aMethod, ValueType&& aValue) {
     return (aThisVal->*aMethod)();
   }
@@ -513,7 +514,7 @@ class MozPromise : public MozPromiseBase {
   // Called when promise chaining is supported.
   template <bool SupportChaining, typename ThisType, typename MethodType,
             typename ValueType, typename CompletionPromiseType>
-  static typename EnableIf<SupportChaining, void>::Type InvokeCallbackMethod(
+  static std::enable_if_t<SupportChaining, void> InvokeCallbackMethod(
       ThisType* aThisVal, MethodType aMethod, ValueType&& aValue,
       CompletionPromiseType&& aCompletionPromise) {
     auto p = InvokeMethod(aThisVal, aMethod, std::forward<ValueType>(aValue));
@@ -525,7 +526,7 @@ class MozPromise : public MozPromiseBase {
   // Called when promise chaining is not supported.
   template <bool SupportChaining, typename ThisType, typename MethodType,
             typename ValueType, typename CompletionPromiseType>
-  static typename EnableIf<!SupportChaining, void>::Type InvokeCallbackMethod(
+  static std::enable_if_t<!SupportChaining, void> InvokeCallbackMethod(
       ThisType* aThisVal, MethodType aMethod, ValueType&& aValue,
       CompletionPromiseType&& aCompletionPromise) {
     MOZ_DIAGNOSTIC_ASSERT(
@@ -556,7 +557,7 @@ class MozPromise : public MozPromiseBase {
     // Fall back to MozPromise when promise chaining is not supported to make
     // code compile.
     using PromiseType =
-        typename Conditional<SupportChaining::value, R1, MozPromise>::Type;
+        std::conditional_t<SupportChaining::value, R1, MozPromise>;
 
    public:
     ThenValue(nsISerialEventTarget* aResponseTarget, ThisType* aThisVal,
@@ -619,7 +620,7 @@ class MozPromise : public MozPromiseBase {
     // Fall back to MozPromise when promise chaining is not supported to make
     // code compile.
     using PromiseType =
-        typename Conditional<SupportChaining::value, R1, MozPromise>::Type;
+        std::conditional_t<SupportChaining::value, R1, MozPromise>;
 
    public:
     ThenValue(nsISerialEventTarget* aResponseTarget, ThisType* aThisVal,
@@ -679,7 +680,7 @@ class MozPromise : public MozPromiseBase {
     // Fall back to MozPromise when promise chaining is not supported to make
     // code compile.
     using PromiseType =
-        typename Conditional<SupportChaining::value, R1, MozPromise>::Type;
+        std::conditional_t<SupportChaining::value, R1, MozPromise>;
 
    public:
     ThenValue(nsISerialEventTarget* aResponseTarget,
@@ -749,7 +750,7 @@ class MozPromise : public MozPromiseBase {
     // Fall back to MozPromise when promise chaining is not supported to make
     // code compile.
     using PromiseType =
-        typename Conditional<SupportChaining::value, R1, MozPromise>::Type;
+        std::conditional_t<SupportChaining::value, R1, MozPromise>;
 
    public:
     ThenValue(nsISerialEventTarget* aResponseTarget,
@@ -873,8 +874,8 @@ class MozPromise : public MozPromiseBase {
     }
 
     template <typename... Ts>
-    auto Then(Ts&&... aArgs)
-        -> decltype(DeclVal<PromiseType>().Then(std::forward<Ts>(aArgs)...)) {
+    auto Then(Ts&&... aArgs) -> decltype(
+        std::declval<PromiseType>().Then(std::forward<Ts>(aArgs)...)) {
       return static_cast<RefPtr<PromiseType>>(*this)->Then(
           std::forward<Ts>(aArgs)...);
     }
@@ -1096,29 +1097,18 @@ typedef MozPromise<bool, nsresult, /* IsExclusive = */ false>
  * Class to encapsulate a promise for a particular role. Use this as the member
  * variable for a class whose method returns a promise.
  */
-template <typename PromiseType>
-class MozPromiseHolder {
+template <typename PromiseType, typename ImplType>
+class MozPromiseHolderBase {
  public:
-  MozPromiseHolder() : mMonitor(nullptr) {}
+  MozPromiseHolderBase() = default;
 
-  MozPromiseHolder(MozPromiseHolder&& aOther)
-      : mMonitor(nullptr), mPromise(aOther.mPromise.forget()) {}
+  MozPromiseHolderBase(MozPromiseHolderBase&& aOther) = default;
+  MozPromiseHolderBase& operator=(MozPromiseHolderBase&& aOther) = default;
 
-  // Move semantics.
-  MozPromiseHolder& operator=(MozPromiseHolder&& aOther) {
-    MOZ_ASSERT(!mMonitor && !aOther.mMonitor);
-    MOZ_DIAGNOSTIC_ASSERT(!mPromise);
-    mPromise = aOther.mPromise;
-    aOther.mPromise = nullptr;
-    return *this;
-  }
-
-  ~MozPromiseHolder() { MOZ_ASSERT(!mPromise); }
+  ~MozPromiseHolderBase() { MOZ_ASSERT(!mPromise); }
 
   already_AddRefed<PromiseType> Ensure(const char* aMethodName) {
-    if (mMonitor) {
-      mMonitor->AssertCurrentThreadOwns();
-    }
+    static_cast<ImplType*>(this)->Check();
     if (!mPromise) {
       mPromise = new (typename PromiseType::Private)(aMethodName);
     }
@@ -1126,33 +1116,24 @@ class MozPromiseHolder {
     return p.forget();
   }
 
-  // Provide a Monitor that should always be held when accessing this instance.
-  void SetMonitor(Monitor2* aMonitor) { mMonitor = aMonitor; }
-
   bool IsEmpty() const {
-    if (mMonitor) {
-      mMonitor->AssertCurrentThreadOwns();
-    }
+    static_cast<const ImplType*>(this)->Check();
     return !mPromise;
   }
 
   already_AddRefed<typename PromiseType::Private> Steal() {
-    if (mMonitor) {
-      mMonitor->AssertCurrentThreadOwns();
-    }
+    static_cast<ImplType*>(this)->Check();
     return mPromise.forget();
   }
 
   template <typename ResolveValueType_>
   void Resolve(ResolveValueType_&& aResolveValue, const char* aMethodName) {
-    static_assert(IsConvertible<ResolveValueType_,
-                                typename PromiseType::ResolveValueType>::value,
+    static_assert(std::is_convertible_v<ResolveValueType_,
+                                        typename PromiseType::ResolveValueType>,
                   "Resolve() argument must be implicitly convertible to "
                   "MozPromise's ResolveValueT");
 
-    if (mMonitor) {
-      mMonitor->AssertCurrentThreadOwns();
-    }
+    static_cast<ImplType*>(this)->Check();
     MOZ_ASSERT(mPromise);
     mPromise->Resolve(std::forward<ResolveValueType_>(aResolveValue),
                       aMethodName);
@@ -1169,14 +1150,12 @@ class MozPromiseHolder {
 
   template <typename RejectValueType_>
   void Reject(RejectValueType_&& aRejectValue, const char* aMethodName) {
-    static_assert(IsConvertible<RejectValueType_,
-                                typename PromiseType::RejectValueType>::value,
+    static_assert(std::is_convertible_v<RejectValueType_,
+                                        typename PromiseType::RejectValueType>,
                   "Reject() argument must be implicitly convertible to "
                   "MozPromise's RejectValueT");
 
-    if (mMonitor) {
-      mMonitor->AssertCurrentThreadOwns();
-    }
+    static_cast<ImplType*>(this)->Check();
     MOZ_ASSERT(mPromise);
     mPromise->Reject(std::forward<RejectValueType_>(aRejectValue), aMethodName);
     mPromise = nullptr;
@@ -1193,9 +1172,7 @@ class MozPromiseHolder {
   template <typename ResolveOrRejectValueType_>
   void ResolveOrReject(ResolveOrRejectValueType_&& aValue,
                        const char* aMethodName) {
-    if (mMonitor) {
-      mMonitor->AssertCurrentThreadOwns();
-    }
+    static_cast<ImplType*>(this)->Check();
     MOZ_ASSERT(mPromise);
     mPromise->ResolveOrReject(std::forward<ResolveOrRejectValueType_>(aValue),
                               aMethodName);
@@ -1212,10 +1189,39 @@ class MozPromiseHolder {
   }
 
  private:
-  Monitor2* mMonitor;
   RefPtr<typename PromiseType::Private> mPromise;
 };
 
+template <typename PromiseType>
+class MozPromiseHolder
+    : public MozPromiseHolderBase<PromiseType, MozPromiseHolder<PromiseType>> {
+ public:
+  using MozPromiseHolderBase<
+      PromiseType, MozPromiseHolder<PromiseType>>::MozPromiseHolderBase;
+  static constexpr void Check(){};
+};
+
+template <typename PromiseType>
+class MozMonitoredPromiseHolder
+    : public MozPromiseHolderBase<PromiseType,
+                                  MozMonitoredPromiseHolder<PromiseType>> {
+ public:
+  // Provide a Monitor that should always be held when accessing this instance.
+  explicit MozMonitoredPromiseHolder(Monitor2* const aMonitor)
+      : mMonitor(aMonitor) {
+    MOZ_ASSERT(aMonitor);
+  }
+
+  MozMonitoredPromiseHolder(MozMonitoredPromiseHolder&& aOther) = delete;
+  MozMonitoredPromiseHolder& operator=(MozMonitoredPromiseHolder&& aOther) =
+      delete;
+
+  void Check() const { mMonitor->AssertCurrentThreadOwns(); }
+
+ private:
+  Monitor2* const mMonitor;
+};
+
 /*
  * Class to encapsulate a MozPromise::Request reference. Use this as the member
  * variable for a class waiting on a MozPromise.
@@ -1319,7 +1325,7 @@ class ProxyRunnable : public CancelableRunnable {
 
  private:
   RefPtr<typename PromiseType::Private> mProxyPromise;
-  nsAutoPtr<MethodCall<PromiseType, MethodType, ThisType, Storages...>>
+  UniquePtr<MethodCall<PromiseType, MethodType, ThisType, Storages...>>
       mMethodCall;
 };
 
@@ -1343,7 +1349,7 @@ static RefPtr<PromiseType> InvokeAsyncImpl(
       new (typename PromiseType::Private)(aCallerName);
   RefPtr<ProxyRunnableType> r = new ProxyRunnableType(p, methodCall);
   aTarget->Dispatch(r.forget());
-  return p.forget();
+  return p;
 }
 
 constexpr bool Any() { return false; }
@@ -1364,7 +1370,7 @@ constexpr bool Any(T1 a, Ts... aOthers) {
 // See ParameterStorage in nsThreadUtils.h for help.
 template <typename... Storages, typename PromiseType, typename ThisType,
           typename... ArgTypes, typename... ActualArgTypes,
-          typename EnableIf<sizeof...(Storages) != 0, int>::Type = 0>
+          std::enable_if_t<sizeof...(Storages) != 0, int> = 0>
 static RefPtr<PromiseType> InvokeAsync(
     nsISerialEventTarget* aTarget, ThisType* aThisVal, const char* aCallerName,
     RefPtr<PromiseType> (ThisType::*aMethod)(ArgTypes...),
@@ -1383,14 +1389,14 @@ static RefPtr<PromiseType> InvokeAsync(
 // then move them out of the runnable into the target method parameters.
 template <typename... Storages, typename PromiseType, typename ThisType,
           typename... ArgTypes, typename... ActualArgTypes,
-          typename EnableIf<sizeof...(Storages) == 0, int>::Type = 0>
+          std::enable_if_t<sizeof...(Storages) == 0, int> = 0>
 static RefPtr<PromiseType> InvokeAsync(
     nsISerialEventTarget* aTarget, ThisType* aThisVal, const char* aCallerName,
     RefPtr<PromiseType> (ThisType::*aMethod)(ArgTypes...),
     ActualArgTypes&&... aArgs) {
   static_assert(
       !detail::Any(
-          std::is_pointer_v<typename RemoveReference<ActualArgTypes>::Type>...),
+          std::is_pointer_v<std::remove_reference_t<ActualArgTypes>>...),
       "Cannot pass pointer types through InvokeAsync, Storages must be "
       "provided");
   static_assert(sizeof...(ArgTypes) == sizeof...(ActualArgTypes),
@@ -1459,7 +1465,7 @@ static auto InvokeAsync(nsISerialEventTarget* aTarget, const char* aCallerName,
   auto p = MakeRefPtr<typename PromiseType::Private>(aCallerName);
   auto r = MakeRefPtr<ProxyRunnableType>(p, std::forward<Function>(aFunction));
   aTarget->Dispatch(r.forget());
-  return p.forget();
+  return p;
 }
 
 }  // namespace detail
diff --git a/xpcom/threads/PrioritizedEventQueue.cpp b/xpcom/threads/PrioritizedEventQueue.cpp
index 1c7337c898..87eb07fb02 100644
--- a/xpcom/threads/PrioritizedEventQueue.cpp
+++ b/xpcom/threads/PrioritizedEventQueue.cpp
@@ -12,10 +12,23 @@
 
 using namespace mozilla;
 
-void PrioritizedEventQueue::PutEvent(
-    already_AddRefed<nsIRunnable>&& aEvent, EventQueuePriority aPriority,
-    const AutoLock& aProofOfLock) {
+PrioritizedEventQueue::PrioritizedEventQueue(
+    already_AddRefed<nsIIdlePeriod> aIdlePeriod)
+    : mHighQueue(MakeUnique<EventQueue>(EventQueuePriority::High)),
+      mInputQueue(MakeUnique<EventQueueSized<32>>(EventQueuePriority::Input)),
+      mMediumHighQueue(MakeUnique<EventQueue>(EventQueuePriority::MediumHigh)),
+      mNormalQueue(MakeUnique<EventQueueSized<64>>(EventQueuePriority::Normal)),
+      mDeferredTimersQueue(
+          MakeUnique<EventQueue>(EventQueuePriority::DeferredTimers)),
+      mIdleQueue(MakeUnique<EventQueue>(EventQueuePriority::Idle)),
+      mIdlePeriod(aIdlePeriod) {}
 
+PrioritizedEventQueue::~PrioritizedEventQueue() = default;
+
+void PrioritizedEventQueue::PutEvent(already_AddRefed<nsIRunnable>&& aEvent,
+                                     EventQueuePriority aPriority,
+                                     const AutoLock& aProofOfLock,
+                                     mozilla::TimeDuration* aDelay) {
   // Double check the priority with a QI.
   RefPtr<nsIRunnable> event(aEvent);
   EventQueuePriority priority = aPriority;
@@ -30,22 +43,24 @@ void PrioritizedEventQueue::PutEvent(
 
   switch (priority) {
     case EventQueuePriority::High:
-      mHighQueue->PutEvent(event.forget(), priority, aProofOfLock);
+      mHighQueue->PutEvent(event.forget(), priority, aProofOfLock, aDelay);
       break;
     case EventQueuePriority::Input:
-      mInputQueue->PutEvent(event.forget(), priority, aProofOfLock);
+      mInputQueue->PutEvent(event.forget(), priority, aProofOfLock, aDelay);
       break;
     case EventQueuePriority::MediumHigh:
-      mMediumHighQueue->PutEvent(event.forget(), priority, aProofOfLock);
+      mMediumHighQueue->PutEvent(event.forget(), priority, aProofOfLock,
+                                 aDelay);
       break;
     case EventQueuePriority::Normal:
-      mNormalQueue->PutEvent(event.forget(), priority, aProofOfLock);
+      mNormalQueue->PutEvent(event.forget(), priority, aProofOfLock, aDelay);
       break;
     case EventQueuePriority::DeferredTimers:
-      mDeferredTimersQueue->PutEvent(event.forget(), priority, aProofOfLock);
+      mDeferredTimersQueue->PutEvent(event.forget(), priority, aProofOfLock,
+                                     aDelay);
       break;
     case EventQueuePriority::Idle:
-      mIdleQueue->PutEvent(event.forget(), priority, aProofOfLock);
+      mIdleQueue->PutEvent(event.forget(), priority, aProofOfLock, aDelay);
       break;
     case EventQueuePriority::Count:
       MOZ_CRASH("EventQueuePriority::Count isn't a valid priority");
@@ -174,88 +189,102 @@ EventQueuePriority PrioritizedEventQueue::SelectQueue(
   return queue;
 }
 
+// The delay returned is the queuing delay a hypothetical Input event would
+// see due to the current running event if it had arrived while the current
+// event was queued.  This means that any event running at  priority below
+// Input doesn't cause queuing delay for Input events, and we return
+// TimeDuration() for those cases.
 already_AddRefed<nsIRunnable> PrioritizedEventQueue::GetEvent(
-    EventQueuePriority* aPriority, const AutoLock& aProofOfLock) {
+    EventQueuePriority* aPriority, const AutoLock& aProofOfLock,
+    mozilla::TimeDuration* aHypotheticalInputEventDelay) {
   auto guard =
       MakeScopeExit([&] { mHasPendingEventsPromisedIdleEvent = false; });
 
-#ifndef RELEASE_OR_BETA
-  // Clear mNextIdleDeadline so that it is possible to determine that
-  // we're running an idle runnable in ProcessNextEvent.
-  *mNextIdleDeadline = TimeStamp();
-#endif
-
   EventQueuePriority queue = SelectQueue(true, aProofOfLock);
 
   if (aPriority) {
     *aPriority = queue;
   }
 
-  if (queue == EventQueuePriority::High) {
-    nsCOMPtr<nsIRunnable> event = mHighQueue->GetEvent(aPriority, aProofOfLock);
-    MOZ_ASSERT(event);
-    mInputHandlingStartTime = TimeStamp();
-    mProcessHighPriorityQueue = false;
-    return event.forget();
-  }
+  // Since Input events will only be delayed behind Input or High events,
+  // the amount of time a lower-priority event spent in the queue is
+  // irrelevant in knowing how long an input event would be delayed.
+  // Alternatively, we could export the delay and let the higher-level code
+  // key off the returned priority level (though then it'd need to know
+  // if the thread's queue was a PrioritizedEventQueue or normal/other
+  // EventQueue).
+  nsCOMPtr<nsIRunnable> event;
+  switch (queue) {
+    default:
+      MOZ_CRASH();
+      break;
 
-  if (queue == EventQueuePriority::Input) {
-    nsCOMPtr<nsIRunnable> event =
-        mInputQueue->GetEvent(aPriority, aProofOfLock);
-    MOZ_ASSERT(event);
-    return event.forget();
-  }
+    case EventQueuePriority::High:
+      event = mHighQueue->GetEvent(aPriority, aProofOfLock,
+                                   aHypotheticalInputEventDelay);
+      MOZ_ASSERT(event);
+      mInputHandlingStartTime = TimeStamp();
+      mProcessHighPriorityQueue = false;
+      break;
 
-  if (queue == EventQueuePriority::MediumHigh) {
-    nsCOMPtr<nsIRunnable> event =
-        mMediumHighQueue->GetEvent(aPriority, aProofOfLock);
-    return event.forget();
-  }
+    case EventQueuePriority::Input:
+      event = mInputQueue->GetEvent(aPriority, aProofOfLock,
+                                    aHypotheticalInputEventDelay);
+      MOZ_ASSERT(event);
+      break;
 
-  if (queue == EventQueuePriority::Normal) {
-    nsCOMPtr<nsIRunnable> event =
-        mNormalQueue->GetEvent(aPriority, aProofOfLock);
-    return event.forget();
-  }
+      // All queue priorities below Input don't add their queuing time to the
+      // time an input event will be delayed, so report 0 for time-in-queue
+      // if we're below Input; input events will only be delayed by the time
+      // an event actually runs (if the event is below Input event's priority)
+    case EventQueuePriority::MediumHigh:
+      event = mMediumHighQueue->GetEvent(aPriority, aProofOfLock);
+      *aHypotheticalInputEventDelay = TimeDuration();
+      break;
 
-  // If we get here, then all queues except deferredtimers and idle are empty.
-  MOZ_ASSERT(queue == EventQueuePriority::Idle ||
-             queue == EventQueuePriority::DeferredTimers);
+    case EventQueuePriority::Normal:
+      event = mNormalQueue->GetEvent(aPriority, aProofOfLock);
+      *aHypotheticalInputEventDelay = TimeDuration();
+      break;
 
-  if (mIdleQueue->IsEmpty(aProofOfLock) &&
-      mDeferredTimersQueue->IsEmpty(aProofOfLock)) {
-    MOZ_ASSERT(!mHasPendingEventsPromisedIdleEvent);
-    return nullptr;
-  }
+    case EventQueuePriority::Idle:
+    case EventQueuePriority::DeferredTimers:
+      *aHypotheticalInputEventDelay = TimeDuration();
+      // If we get here, then all queues except deferredtimers and idle are
+      // empty.
 
-  TimeStamp idleDeadline = GetIdleDeadline();
-  if (!idleDeadline) {
-    return nullptr;
-  }
+      if (mIdleQueue->IsEmpty(aProofOfLock) &&
+          mDeferredTimersQueue->IsEmpty(aProofOfLock)) {
+        MOZ_ASSERT(!mHasPendingEventsPromisedIdleEvent);
+        return nullptr;
+      }
+
+      TimeStamp idleDeadline = GetIdleDeadline();
+      if (!idleDeadline) {
+        return nullptr;
+      }
+
+      event = mDeferredTimersQueue->GetEvent(aPriority, aProofOfLock);
+      if (!event) {
+        event = mIdleQueue->GetEvent(aPriority, aProofOfLock);
+      }
+      if (event) {
+        nsCOMPtr<nsIIdleRunnable> idleEvent = do_QueryInterface(event);
+        if (idleEvent) {
+          idleEvent->SetDeadline(idleDeadline);
+        }
+      }
+      break;
+  }  // switch (queue)
 
-  nsCOMPtr<nsIRunnable> event =
-      mDeferredTimersQueue->GetEvent(aPriority, aProofOfLock);
   if (!event) {
-    event = mIdleQueue->GetEvent(aPriority, aProofOfLock);
-  }
-  if (event) {
-    nsCOMPtr<nsIIdleRunnable> idleEvent = do_QueryInterface(event);
-    if (idleEvent) {
-      idleEvent->SetDeadline(idleDeadline);
-    }
-
-#ifndef RELEASE_OR_BETA
-    // Store the next idle deadline to be able to determine budget use
-    // in ProcessNextEvent.
-    *mNextIdleDeadline = idleDeadline;
-#endif
+    *aHypotheticalInputEventDelay = TimeDuration();
   }
 
   return event.forget();
 }
 
-bool PrioritizedEventQueue::IsEmpty(
-    const AutoLock& aProofOfLock) {
+bool PrioritizedEventQueue::IsEmpty(const AutoLock& aProofOfLock) {
   // Just check IsEmpty() on the sub-queues. Don't bother checking the idle
   // deadline since that only determines whether an idle event is ready or not.
   return mHighQueue->IsEmpty(aProofOfLock) &&
@@ -266,8 +295,7 @@ bool PrioritizedEventQueue::IsEmpty(
          mIdleQueue->IsEmpty(aProofOfLock);
 }
 
-bool PrioritizedEventQueue::HasReadyEvent(
-    const AutoLock& aProofOfLock) {
+bool PrioritizedEventQueue::HasReadyEvent(const AutoLock& aProofOfLock) {
   mHasPendingEventsPromisedIdleEvent = false;
 
   EventQueuePriority queue = SelectQueue(false, aProofOfLock);
@@ -307,8 +335,7 @@ bool PrioritizedEventQueue::HasPendingHighPriorityEvents(
   return !mHighQueue->IsEmpty(aProofOfLock);
 }
 
-size_t PrioritizedEventQueue::Count(
-    const AutoLock& aProofOfLock) const {
+size_t PrioritizedEventQueue::Count(const AutoLock& aProofOfLock) const {
   MOZ_CRASH("unimplemented");
 }
 
diff --git a/xpcom/threads/PrioritizedEventQueue.h b/xpcom/threads/PrioritizedEventQueue.h
index 5dd8ecd3af..b788b2fbfd 100644
--- a/xpcom/threads/PrioritizedEventQueue.h
+++ b/xpcom/threads/PrioritizedEventQueue.h
@@ -38,22 +38,18 @@ class PrioritizedEventQueue final : public AbstractEventQueue {
  public:
   static const bool SupportsPrioritization = true;
 
-  explicit PrioritizedEventQueue(already_AddRefed<nsIIdlePeriod> aIdlePeriod)
-      : mHighQueue(MakeUnique<EventQueue>(EventQueuePriority::High)),
-        mInputQueue(MakeUnique<EventQueue>(EventQueuePriority::Input)),
-        mMediumHighQueue(
-            MakeUnique<EventQueue>(EventQueuePriority::MediumHigh)),
-        mNormalQueue(MakeUnique<EventQueue>(EventQueuePriority::Normal)),
-        mDeferredTimersQueue(
-            MakeUnique<EventQueue>(EventQueuePriority::DeferredTimers)),
-        mIdleQueue(MakeUnique<EventQueue>(EventQueuePriority::Idle)),
-        mIdlePeriod(aIdlePeriod) {}
+  explicit PrioritizedEventQueue(already_AddRefed<nsIIdlePeriod> aIdlePeriod);
+
+  virtual ~PrioritizedEventQueue();
 
   void PutEvent(already_AddRefed<nsIRunnable>&& aEvent,
-                EventQueuePriority aPriority,
-                const AutoLock& aProofOfLock) final;
+                EventQueuePriority aPriority, const AutoLock& aProofOfLock,
+                mozilla::TimeDuration* aDelay = nullptr) final;
+  // See PrioritizedEventQueue.cpp for explanation of
+  // aHypotheticalInputEventDelay
   already_AddRefed<nsIRunnable> GetEvent(
-      EventQueuePriority* aPriority, const AutoLock& aProofOfLock) final;
+      EventQueuePriority* aPriority, const AutoLock& aProofOfLock,
+      mozilla::TimeDuration* aHypotheticalInputEventDelay = nullptr) final;
 
   bool IsEmpty(const AutoLock& aProofOfLock) final;
   size_t Count(const AutoLock& aProofOfLock) const final;
@@ -66,15 +62,6 @@ class PrioritizedEventQueue final : public AbstractEventQueue {
   // least as long as the queue.
   void SetMutexRef(Lock& aMutex) { mMutex = &aMutex; }
 
-#ifndef RELEASE_OR_BETA
-  // nsThread.cpp sends telemetry containing the most recently computed idle
-  // deadline. We store a reference to a field in nsThread where this deadline
-  // will be stored so that it can be fetched quickly for telemetry.
-  void SetNextIdleDeadlineRef(TimeStamp& aDeadline) {
-    mNextIdleDeadline = &aDeadline;
-  }
-#endif
-
   void EnableInputEventPrioritization(const AutoLock& aProofOfLock) final;
   void FlushInputEventPrioritization(const AutoLock& aProofOfLock) final;
   void SuspendInputEventPrioritization(const AutoLock& aProofOfLock) final;
@@ -106,9 +93,9 @@ class PrioritizedEventQueue final : public AbstractEventQueue {
   mozilla::TimeStamp GetIdleDeadline();
 
   UniquePtr<EventQueue> mHighQueue;
-  UniquePtr<EventQueue> mInputQueue;
+  UniquePtr<EventQueueSized<32>> mInputQueue;
   UniquePtr<EventQueue> mMediumHighQueue;
-  UniquePtr<EventQueue> mNormalQueue;
+  UniquePtr<EventQueueSized<64>> mNormalQueue;
   UniquePtr<EventQueue> mDeferredTimersQueue;
   UniquePtr<EventQueue> mIdleQueue;
 
@@ -116,11 +103,8 @@ class PrioritizedEventQueue final : public AbstractEventQueue {
   // a pointer to it here.
   Lock* mMutex = nullptr;
 
-#ifndef RELEASE_OR_BETA
-  // Pointer to a place where the most recently computed idle deadline is
-  // stored.
-  TimeStamp* mNextIdleDeadline = nullptr;
-#endif
+  TimeDuration mLastEventDelay;
+  TimeStamp mLastEventStart;
 
   // Try to process one high priority runnable after each normal
   // priority runnable. This gives the processing model HTML spec has for
diff --git a/xpcom/threads/Queue.h b/xpcom/threads/Queue.h
index f1751ca2ad..9c77f0eb09 100644
--- a/xpcom/threads/Queue.h
+++ b/xpcom/threads/Queue.h
@@ -9,6 +9,9 @@
 
 namespace mozilla {
 
+// define to turn on additional (DEBUG) asserts
+// #define EXTRA_ASSERTS 1
+
 // A queue implements a singly linked list of pages, each of which contains some
 // number of elements. Since the queue needs to store a "next" pointer, the
 // actual number of elements per page won't be quite as many as were requested.
@@ -17,6 +20,32 @@ namespace mozilla {
 // zeroes. The class also fails to call the destructor on items. However, it
 // will only destroy items after it has moved out their contents. The queue is
 // required to be empty when it is destroyed.
+//
+// Each page consists of N entries.  We use the head buffer as a circular buffer
+// if it's the only buffer; if we have more than one buffer when the head is
+// empty we release it.  This avoids occasional freeing and reallocating buffers
+// every N entries.  We'll still allocate and free every N if the normal queue
+// depth is greated than N.  A fancier solution would be to move an empty Head
+// buffer to be an empty tail buffer, freeing if we have multiple empty tails,
+// but that probably isn't worth it.
+//
+// Cases:
+//   a) single buffer, circular
+//      Push: if not full:
+//              Add to tail, bump tail and reset to 0 if at end
+//            full:
+//              Add new page, insert there and set tail to 1
+//      Pop:
+//            take entry and bump head, reset to 0 if at end
+//   b) multiple buffers:
+//      Push: if not full:
+//              Add to tail, bump tail
+//            full:
+//              Add new page, insert there and set tail to 1
+//      Pop:
+//            take entry and bump head, reset to 0 if at end
+//            if buffer is empty, free head buffer and promote next to head
+//
 template <class T, size_t RequestedItemsPerPage = 256>
 class Queue {
  public:
@@ -31,84 +60,117 @@ class Queue {
   }
 
   T& Push(T&& aElement) {
+#if defined(EXTRA_ASSERTS) && DEBUG
+    size_t original_length = Count();
+#endif
     if (!mHead) {
       mHead = NewPage();
       MOZ_ASSERT(mHead);
 
       mTail = mHead;
+      T& eltLocation = mTail->mEvents[0];
+      eltLocation = std::move(aElement);
       mOffsetHead = 0;
-      mOffsetTail = 0;
-    } else if (mOffsetTail == ItemsPerPage) {
+      mHeadLength = 1;
+#ifdef EXTRA_ASSERTS
+      MOZ_ASSERT(Count() == original_length + 1);
+#endif
+      return eltLocation;
+    }
+    if ((mHead == mTail && mHeadLength == ItemsPerPage) ||
+        (mHead != mTail && mTailLength == ItemsPerPage)) {
+      // either we have one (circular) buffer and it's full, or
+      // we have multiple buffers and the last buffer is full
       Page* page = NewPage();
       MOZ_ASSERT(page);
 
       mTail->mNext = page;
       mTail = page;
-      mOffsetTail = 0;
+      T& eltLocation = page->mEvents[0];
+      eltLocation = std::move(aElement);
+      mTailLength = 1;
+#ifdef EXTRA_ASSERTS
+      MOZ_ASSERT(Count() == original_length + 1);
+#endif
+      return eltLocation;
     }
-
-    T& eltLocation = mTail->mEvents[mOffsetTail];
+    if (mHead == mTail) {
+      // we have space in the (single) head buffer
+      uint16_t offset = (mOffsetHead + mHeadLength++) % ItemsPerPage;
+      T& eltLocation = mTail->mEvents[offset];
+      eltLocation = std::move(aElement);
+#ifdef EXTRA_ASSERTS
+      MOZ_ASSERT(Count() == original_length + 1);
+#endif
+      return eltLocation;
+    }
+    // else we have space to insert into last buffer
+    T& eltLocation = mTail->mEvents[mTailLength++];
     eltLocation = std::move(aElement);
-    ++mOffsetTail;
-
+#ifdef EXTRA_ASSERTS
+    MOZ_ASSERT(Count() == original_length + 1);
+#endif
     return eltLocation;
   }
 
   bool IsEmpty() const {
-    return !mHead || (mHead == mTail && mOffsetHead == mOffsetTail);
+    return !mHead || (mHead == mTail && mHeadLength == 0);
   }
 
   T Pop() {
+#if defined(EXTRA_ASSERTS) && DEBUG
+    size_t original_length = Count();
+#endif
     MOZ_ASSERT(!IsEmpty());
 
-    MOZ_ASSERT(mOffsetHead < ItemsPerPage);
-    MOZ_ASSERT_IF(mHead == mTail, mOffsetHead <= mOffsetTail);
-    T result = std::move(mHead->mEvents[mOffsetHead++]);
+    T result = std::move(mHead->mEvents[mOffsetHead]);
+    mOffsetHead = (mOffsetHead + 1) % ItemsPerPage;
+    mHeadLength -= 1;
 
-    MOZ_ASSERT(mOffsetHead <= ItemsPerPage);
-
-    // Check if mHead points to empty Page
-    if (mOffsetHead == ItemsPerPage) {
+    // Check if mHead points to empty (circular) Page and we have more
+    // pages
+    if (mHead != mTail && mHeadLength == 0) {
       Page* dead = mHead;
       mHead = mHead->mNext;
       free(dead);
       mOffsetHead = 0;
+      // if there are still >1 pages, the new head is full.
+      if (mHead != mTail) {
+        mHeadLength = ItemsPerPage;
+      } else {
+        mHeadLength = mTailLength;
+        mTailLength = 0;
+      }
     }
 
+#ifdef EXTRA_ASSERTS
+    MOZ_ASSERT(Count() == original_length - 1);
+#endif
     return result;
   }
 
-  void FirstElementAssertions() const {
-    MOZ_ASSERT(!IsEmpty());
-    MOZ_ASSERT(mOffsetHead < ItemsPerPage);
-    MOZ_ASSERT_IF(mHead == mTail, mOffsetHead <= mOffsetTail);
-  }
-
   T& FirstElement() {
-    FirstElementAssertions();
+    MOZ_ASSERT(!IsEmpty());
     return mHead->mEvents[mOffsetHead];
   }
 
   const T& FirstElement() const {
-    FirstElementAssertions();
+    MOZ_ASSERT(!IsEmpty());
     return mHead->mEvents[mOffsetHead];
   }
 
-  void LastElementAssertions() const {
-    MOZ_ASSERT(!IsEmpty());
-    MOZ_ASSERT(mOffsetTail > 0);
-    MOZ_ASSERT(mOffsetTail <= ItemsPerPage);
-    MOZ_ASSERT_IF(mHead == mTail, mOffsetHead <= mOffsetTail);
-  }
-
   T& LastElement() {
-    LastElementAssertions();
-    return mTail->mEvents[mOffsetTail - 1];
+    MOZ_ASSERT(!IsEmpty());
+    uint16_t offset =
+        mHead == mTail ? mOffsetHead + mHeadLength - 1 : mTailLength - 1;
+    return mTail->mEvents[offset];
   }
 
   const T& LastElement() const {
-    LastElementAssertions();
-    return mTail->mEvents[mOffsetTail - 1];
+    MOZ_ASSERT(!IsEmpty());
+    uint16_t offset =
+        mHead == mTail ? mOffsetHead + mHeadLength - 1 : mTailLength - 1;
+    return mTail->mEvents[offset];
   }
 
   size_t Count() const {
@@ -117,28 +179,15 @@ class Queue {
       return 0;
     }
 
-    /* How we count the number of events in the queue:
-     * 1. Let pageCount(x, y) denote the number of pages excluding the tail page
-     *    where x is the index of head page and y is the index of the tail page.
-     * 2. Then we have pageCount(x, y) = y - x.
-     *
-     * Ex: pageCount(0, 0) = 0 where both head and tail pages point to page 0.
-     *     pageCount(0, 1) = 1 where head points to page 0 and tail points
-     *     page 1.
-     *
-     * 3. number of events = (ItemsPerPage * pageCount(x, y))
-     *      - (empty slots in head page) + (non-empty slots in tail page)
-     *      = (ItemsPerPage * pageCount(x, y)) - mOffsetHead + mOffsetTail
-     */
-
-    int count = -mOffsetHead;
-
-    // Compute (ItemsPerPage * pageCount(x, y))
-    for (Page* page = mHead; page != mTail; page = page->mNext) {
+    // Compute full (intermediate) pages; Doesn't count first or last page
+    int count = 0;
+    // 1 buffer will have mHead == mTail; 2 will have mHead->mNext == mTail
+    for (Page* page = mHead; page != mTail && page->mNext != mTail;
+         page = page->mNext) {
       count += ItemsPerPage;
     }
-
-    count += mOffsetTail;
+    // add first and last page
+    count += mHeadLength + mTailLength;
     MOZ_ASSERT(count >= 0);
 
     return count;
@@ -181,8 +230,9 @@ class Queue {
   Page* mHead = nullptr;
   Page* mTail = nullptr;
 
-  uint16_t mOffsetHead = 0;  // offset into mHead where next item is removed
-  uint16_t mOffsetTail = 0;  // offset into mTail where next item is added
+  uint16_t mOffsetHead = 0;  // Read position in head page
+  uint16_t mHeadLength = 0;  // Number of items in the head page
+  uint16_t mTailLength = 0;  // Number of items in the tail page
 };
 
 }  // namespace mozilla
diff --git a/xpcom/threads/SyncRunnable.h b/xpcom/threads/SyncRunnable.h
index 8793d1698c..9d6d45199c 100644
--- a/xpcom/threads/SyncRunnable.h
+++ b/xpcom/threads/SyncRunnable.h
@@ -5,10 +5,12 @@
 #ifndef mozilla_SyncRunnable_h
 #define mozilla_SyncRunnable_h
 
-#include "nsThreadUtils.h"
+#include <utility>
+
 #include "mozilla/AbstractThread.h"
+#include "mozilla/dom/JSExecutionManager.h"
 #include "mozilla/Monitor2.h"
-#include "mozilla/Move.h"
+#include "nsThreadUtils.h"
 
 namespace mozilla {
 
@@ -58,6 +60,10 @@ class SyncRunnable : public Runnable {
     rv = aThread->Dispatch(this, NS_DISPATCH_NORMAL);
     if (NS_SUCCEEDED(rv)) {
       mozilla::Monitor2AutoLock lock(mMonitor);
+      // This could be synchronously dispatching to a thread currently waiting
+      // for JS execution clearance. Yield JS execution.
+      dom::AutoYieldJSThreadExecution yield;
+
       while (!mDone) {
         lock.Wait();
       }
diff --git a/xpcom/threads/SynchronizedEventQueue.h b/xpcom/threads/SynchronizedEventQueue.h
index fe7a009a41..7d5cec08ce 100644
--- a/xpcom/threads/SynchronizedEventQueue.h
+++ b/xpcom/threads/SynchronizedEventQueue.h
@@ -55,7 +55,8 @@ class ThreadTargetSink {
 class SynchronizedEventQueue : public ThreadTargetSink {
  public:
   virtual already_AddRefed<nsIRunnable> GetEvent(
-      bool aMayWait, EventQueuePriority* aPriority) = 0;
+      bool aMayWait, EventQueuePriority* aPriority,
+      mozilla::TimeDuration* aLastEventDelay = nullptr) = 0;
   virtual bool HasPendingEvent() = 0;
 
   virtual bool HasPendingHighPriorityEvents() = 0;
diff --git a/xpcom/threads/ThreadEventQueue.cpp b/xpcom/threads/ThreadEventQueue.cpp
index 2bf0664797..140c72e958 100644
--- a/xpcom/threads/ThreadEventQueue.cpp
+++ b/xpcom/threads/ThreadEventQueue.cpp
@@ -129,17 +129,19 @@ bool ThreadEventQueue<InnerQueueT>::PutEventInternal(
 
 template <class InnerQueueT>
 already_AddRefed<nsIRunnable> ThreadEventQueue<InnerQueueT>::GetEvent(
-    bool aMayWait, EventQueuePriority* aPriority) {
+    bool aMayWait, EventQueuePriority* aPriority,
+    mozilla::TimeDuration* aLastEventDelay) {
   AutoLock lock(mLock);
 
   nsCOMPtr<nsIRunnable> event;
   for (;;) {
     if (mNestedQueues.IsEmpty()) {
-      event = mBaseQueue->GetEvent(aPriority, lock);
+      event = mBaseQueue->GetEvent(aPriority, lock, aLastEventDelay);
     } else {
       // We always get events from the topmost queue when there are nested
       // queues.
-      event = mNestedQueues.LastElement().mQueue->GetEvent(aPriority, lock);
+      event = mNestedQueues.LastElement().mQueue->GetEvent(aPriority, lock,
+                                                           aLastEventDelay);
     }
 
     if (event || !aMayWait) {
@@ -249,8 +251,10 @@ void ThreadEventQueue<InnerQueueT>::PopEventQueue(nsIEventTarget* aTarget) {
   // Move events from the old queue to the new one.
   nsCOMPtr<nsIRunnable> event;
   EventQueuePriority prio;
-  while ((event = item.mQueue->GetEvent(&prio, lock))) {
-    prevQueue->PutEvent(event.forget(), prio, lock);
+  TimeDuration delay;
+  while ((event = item.mQueue->GetEvent(&prio, lock, &delay))) {
+    // preserve the event delay so far
+    prevQueue->PutEvent(event.forget(), prio, lock, &delay);
   }
 
   mNestedQueues.RemoveLastElement();
diff --git a/xpcom/threads/ThreadEventQueue.h b/xpcom/threads/ThreadEventQueue.h
index 9520f0cf5b..0259926c61 100644
--- a/xpcom/threads/ThreadEventQueue.h
+++ b/xpcom/threads/ThreadEventQueue.h
@@ -34,8 +34,9 @@ class ThreadEventQueue final : public SynchronizedEventQueue {
   bool PutEvent(already_AddRefed<nsIRunnable>&& aEvent,
                 EventQueuePriority aPriority) final;
 
-  already_AddRefed<nsIRunnable> GetEvent(bool aMayWait,
-                                         EventQueuePriority* aPriority) final;
+  already_AddRefed<nsIRunnable> GetEvent(
+      bool aMayWait, EventQueuePriority* aPriority,
+      mozilla::TimeDuration* aLastEventDelay = nullptr) final;
   bool HasPendingEvent() final;
   bool HasPendingHighPriorityEvents() final;
 
diff --git a/xpcom/threads/ThrottledEventQueue.cpp b/xpcom/threads/ThrottledEventQueue.cpp
index 68fee839ea..7c4420eaa8 100644
--- a/xpcom/threads/ThrottledEventQueue.cpp
+++ b/xpcom/threads/ThrottledEventQueue.cpp
@@ -98,7 +98,7 @@ class ThrottledEventQueue::Inner final : public nsISupports {
   //
   // Used from any thread; protected by mMutex. Signals mIdleCondVar when
   // emptied.
-  EventQueue mEventQueue;
+  EventQueueSized<64> mEventQueue;
 
   // The event target we dispatch our events (actually, just our Executor) to.
   //
diff --git a/xpcom/threads/nsIThread.idl b/xpcom/threads/nsIThread.idl
index c911ffa073..2c5378cf2f 100644
--- a/xpcom/threads/nsIThread.idl
+++ b/xpcom/threads/nsIThread.idl
@@ -8,6 +8,9 @@
 #include "mozilla/AlreadyAddRefed.h"
 namespace mozilla {
 class TimeStamp;
+class TimeDurationValueCalculator;
+template <typename T> class BaseTimeDuration;
+typedef BaseTimeDuration<TimeDurationValueCalculator> TimeDuration;
 enum class EventQueuePriority;
 }
 %}
@@ -18,6 +21,7 @@ native EventQueuePriority(mozilla::EventQueuePriority);
 native nsIEventTargetPtr(nsIEventTarget*);
 native nsISerialEventTargetPtr(nsISerialEventTarget*);
 native TimeStamp(mozilla::TimeStamp);
+native TimeDuration(mozilla::TimeDuration);
 
 /**
  * This interface provides a high-level abstraction for an operating system
@@ -174,4 +178,32 @@ interface nsIThread : nsISerialEventTarget
    */
   [noscript] readonly attribute TimeStamp lastLongTaskEnd;
   [noscript] readonly attribute TimeStamp lastLongNonIdleTaskEnd;
+
+  /**
+   * Get information on the timing of the currently-running event.
+   *
+   * @param delay
+   *   The amount of time the current running event in the specified queue waited
+   *   to run. Will return TimeDuration() if the queue is empty or has not run any
+   *   new events since event delay monitoring started.  NOTE: delay will be
+   *   TimeDuration() if this thread uses a PrioritizedEventQueue (i.e. MainThread)
+   *   and the event priority is below Input.
+   * @param start
+   *   The time the currently running event began to run, or TimeStamp() if no
+   *   event is running.
+   */
+  [noscript] void getRunningEventDelay(out TimeDuration delay, out TimeStamp start);
+
+  /**
+   * Set information on the timing of the currently-running event.
+   * Overrides the values returned by getRunningEventDelay
+   *
+   * @param delay
+   *   Delay the running event spent in queues, or TimeDuration() if
+   *   there's no running event.
+   * @param start
+   *   The time the currently running event began to run, or TimeStamp() if no
+   *   event is running.
+   */
+  [noscript] void setRunningEventDelay(in TimeDuration delay, in TimeStamp start);
 };
diff --git a/xpcom/threads/nsProcessCommon.cpp b/xpcom/threads/nsProcessCommon.cpp
index f43b3c9e13..1a14da54ae 100644
--- a/xpcom/threads/nsProcessCommon.cpp
+++ b/xpcom/threads/nsProcessCommon.cpp
@@ -13,7 +13,6 @@
 #include "mozilla/ArrayUtils.h"
 
 #include "nsCOMPtr.h"
-#include "nsAutoPtr.h"
 #include "nsMemory.h"
 #include "nsProcess.h"
 #include "prio.h"
diff --git a/xpcom/threads/nsProxyRelease.h b/xpcom/threads/nsProxyRelease.h
index f2a1dc1042..a12ccd6c7a 100644
--- a/xpcom/threads/nsProxyRelease.h
+++ b/xpcom/threads/nsProxyRelease.h
@@ -5,17 +5,16 @@
 #ifndef nsProxyRelease_h__
 #define nsProxyRelease_h__
 
-#include "nsIEventTarget.h"
-#include "nsCOMPtr.h"
-#include "nsAutoPtr.h"
 #include "MainThreadUtils.h"
-#include "nsPrintfCString.h"
-#include "nsThreadUtils.h"
 #include "mozilla/Likely.h"
 #include "mozilla/Move.h"
 #include "mozilla/SystemGroup.h"
 #include "mozilla/TypeTraits.h"
 #include "mozilla/Unused.h"
+#include "nsCOMPtr.h"
+#include "nsIEventTarget.h"
+#include "nsPrintfCString.h"
+#include "nsThreadUtils.h"
 
 #ifdef XPCOM_GLUE_AVOID_NSPR
 #  error NS_ProxyRelease implementation depends on NSPR.
@@ -110,7 +109,7 @@ struct ProxyReleaseChooser<true> {
  * Ensures that the delete of a smart pointer occurs on the target thread.
  *
  * @param aName
- *        the labelling name of the runnable involved in the releasing
+ *        the labelling name of the runnable involved in the releasing.
  * @param aTarget
  *        the target thread where the doomed object should be released.
  * @param aDoomed
@@ -181,15 +180,15 @@ inline NS_HIDDEN_(void)
  *
  * Classes like XPCWrappedJS are main-thread-only, which means that it is
  * forbidden to call methods on instances of these classes off the main thread.
- * For various reasons (see bug 771074), this restriction recently began to
- * apply to AddRef/Release as well.
+ * For various reasons (see bug 771074), this restriction applies to
+ * AddRef/Release as well.
  *
  * This presents a problem for consumers that wish to hold a callback alive
  * on non-main-thread code. A common example of this is the proxy callback
  * pattern, where non-main-thread code holds a strong-reference to the callback
  * object, and dispatches new Runnables (also with a strong reference) to the
  * main thread in order to execute the callback. This involves several AddRef
- * and Release calls on the other thread, which is (now) verboten.
+ * and Release calls on the other thread, which is verboten.
  *
  * The basic idea of this class is to introduce a layer of indirection.
  * nsMainThreadPtrHolder is a threadsafe reference-counted class that internally
@@ -199,10 +198,10 @@ inline NS_HIDDEN_(void)
  * to the holder anywhere they please. These references are meant to be opaque
  * when accessed off-main-thread (assertions enforce this).
  *
- * The semantics of RefPtr<nsMainThreadPtrHolder<T> > would be cumbersome, so
- * we also introduce nsMainThreadPtrHandle<T>, which is conceptually identical
- * to the above (though it includes various convenience methods). The basic
- * pattern is as follows.
+ * The semantics of RefPtr<nsMainThreadPtrHolder<T>> would be cumbersome, so we
+ * also introduce nsMainThreadPtrHandle<T>, which is conceptually identical to
+ * the above (though it includes various convenience methods). The basic pattern
+ * is as follows.
  *
  * // On the main thread:
  * nsCOMPtr<nsIFooCallback> callback = ...;
@@ -217,14 +216,14 @@ inline NS_HIDDEN_(void)
 template <class T>
 class MOZ_IS_SMARTPTR_TO_REFCOUNTED nsMainThreadPtrHolder final {
  public:
-  // We can only acquire a pointer on the main thread. We to fail fast for
+  // We can only acquire a pointer on the main thread. We want to fail fast for
   // threading bugs, so by default we assert if our pointer is used or acquired
   // off-main-thread. But some consumers need to use the same pointer for
   // multiple classes, some of which are main-thread-only and some of which
   // aren't. So we allow them to explicitly disable this strict checking.
   nsMainThreadPtrHolder(const char* aName, T* aPtr, bool aStrict = true,
                         nsIEventTarget* aMainThreadEventTarget = nullptr)
-      : mRawPtr(nullptr),
+      : mRawPtr(aPtr),
         mStrict(aStrict),
         mMainThreadEventTarget(aMainThreadEventTarget)
 #ifndef RELEASE_OR_BETA
@@ -235,7 +234,7 @@ class MOZ_IS_SMARTPTR_TO_REFCOUNTED nsMainThreadPtrHolder final {
     // We can only AddRef our pointer on the main thread, which means that the
     // holder must be constructed on the main thread.
     MOZ_ASSERT(!mStrict || NS_IsMainThread());
-    NS_IF_ADDREF(mRawPtr = aPtr);
+    NS_IF_ADDREF(mRawPtr);
   }
   nsMainThreadPtrHolder(const char* aName, already_AddRefed<T> aPtr,
                         bool aStrict = true,
@@ -252,6 +251,11 @@ class MOZ_IS_SMARTPTR_TO_REFCOUNTED nsMainThreadPtrHolder final {
     // call on any thread.
   }
 
+  // Copy constructor and operator= deleted. Once constructed, the holder is
+  // immutable.
+  T& operator=(nsMainThreadPtrHolder& aOther) = delete;
+  nsMainThreadPtrHolder(const nsMainThreadPtrHolder& aOther) = delete;
+
  private:
   // We can be released on any thread.
   ~nsMainThreadPtrHolder() {
@@ -273,7 +277,7 @@ class MOZ_IS_SMARTPTR_TO_REFCOUNTED nsMainThreadPtrHolder final {
   }
 
  public:
-  T* get() {
+  T* get() const {
     // Nobody should be touching the raw pointer off-main-thread.
     if (mStrict && MOZ_UNLIKELY(!NS_IsMainThread())) {
       NS_ERROR("Can't dereference nsMainThreadPtrHolder off main thread");
@@ -291,27 +295,20 @@ class MOZ_IS_SMARTPTR_TO_REFCOUNTED nsMainThreadPtrHolder final {
 
  private:
   // Our wrapped pointer.
-  T* mRawPtr;
+  T* mRawPtr = nullptr;
 
   // Whether to strictly enforce thread invariants in this class.
-  bool mStrict;
+  bool mStrict = true;
 
   nsCOMPtr<nsIEventTarget> mMainThreadEventTarget;
 
 #ifndef RELEASE_OR_BETA
   const char* mName = nullptr;
 #endif
-
-  // Copy constructor and operator= not implemented. Once constructed, the
-  // holder is immutable.
-  T& operator=(nsMainThreadPtrHolder& aOther);
-  nsMainThreadPtrHolder(const nsMainThreadPtrHolder& aOther);
 };
 
 template <class T>
 class MOZ_IS_SMARTPTR_TO_REFCOUNTED nsMainThreadPtrHandle {
-  RefPtr<nsMainThreadPtrHolder<T>> mPtr;
-
  public:
   nsMainThreadPtrHandle() : mPtr(nullptr) {}
   MOZ_IMPLICIT nsMainThreadPtrHandle(decltype(nullptr)) : mPtr(nullptr) {}
@@ -322,18 +319,24 @@ class MOZ_IS_SMARTPTR_TO_REFCOUNTED nsMainThreadPtrHandle {
       : mPtr(aHolder) {}
   nsMainThreadPtrHandle(const nsMainThreadPtrHandle& aOther)
       : mPtr(aOther.mPtr) {}
+  nsMainThreadPtrHandle(nsMainThreadPtrHandle&& aOther)
+      : mPtr(std::move(aOther.mPtr)) {}
   nsMainThreadPtrHandle& operator=(const nsMainThreadPtrHandle& aOther) {
     mPtr = aOther.mPtr;
     return *this;
   }
+  nsMainThreadPtrHandle& operator=(nsMainThreadPtrHandle&& aOther) {
+    mPtr = std::move(aOther.mPtr);
+    return *this;
+  }
   nsMainThreadPtrHandle& operator=(nsMainThreadPtrHolder<T>* aHolder) {
     mPtr = aHolder;
     return *this;
   }
 
   // These all call through to nsMainThreadPtrHolder, and thus implicitly
-  // assert that we're on the main thread. Off-main-thread consumers must treat
-  // these handles as opaque.
+  // assert that we're on the main thread (if strict). Off-main-thread consumers
+  // must treat these handles as opaque.
   T* get() const {
     if (mPtr) {
       return mPtr.get()->get();
@@ -357,18 +360,11 @@ class MOZ_IS_SMARTPTR_TO_REFCOUNTED nsMainThreadPtrHandle {
   bool operator==(decltype(nullptr)) const { return mPtr == nullptr; }
   bool operator!=(decltype(nullptr)) const { return mPtr != nullptr; }
   bool operator!() const { return !mPtr || !*mPtr; }
+
+ private:
+  RefPtr<nsMainThreadPtrHolder<T>> mPtr;
 };
 
-namespace mozilla {
-
-template <typename T>
-using PtrHolder = nsMainThreadPtrHolder<T>;
-
-template <typename T>
-using PtrHandle = nsMainThreadPtrHandle<T>;
-
-}  // namespace mozilla
-
 class nsCycleCollectionTraversalCallback;
 template <typename T>
 void CycleCollectionNoteChild(nsCycleCollectionTraversalCallback& aCallback,
diff --git a/xpcom/threads/nsThread.cpp b/xpcom/threads/nsThread.cpp
index 80d88ec002..9850a3be19 100644
--- a/xpcom/threads/nsThread.cpp
+++ b/xpcom/threads/nsThread.cpp
@@ -16,7 +16,6 @@
 #include "nsMemoryPressure.h"
 #include "nsThreadManager.h"
 #include "nsIClassInfoImpl.h"
-#include "nsAutoPtr.h"
 #include "nsCOMPtr.h"
 #include "nsQueryObject.h"
 #include "pratom.h"
@@ -25,7 +24,7 @@
 #include "mozilla/Logging.h"
 #include "nsIObserverService.h"
 #include "mozilla/IntegerTypeTraits.h"
-//#include "mozilla/IOInterposer.h"
+#include "mozilla/IOInterposer.h"
 #include "mozilla/ipc/MessageChannel.h"
 #include "mozilla/ipc/BackgroundChild.h"
 #include "mozilla/Preferences.h"
@@ -254,6 +253,12 @@ struct nsThreadShutdownContext {
   bool mIsMainThreadJoining;
 };
 
+bool nsThread::ShutdownContextsComp::Equals(
+    const ShutdownContexts::elem_type& a,
+    const ShutdownContexts::elem_type::Pointer b) const {
+  return a.get() == b;
+}
+
 // This event is responsible for notifying nsThread::Shutdown that it is time
 // to call PR_JoinThread. It implements nsICancelableRunnable so that it can
 // run on a DOM Worker thread (where all events must implement
@@ -428,7 +433,7 @@ void nsThread::ThreadFunc(void* aArg) {
   // Inform the ThreadManager
   nsThreadManager::get().RegisterCurrentThread(*self);
 
-  //mozilla::IOInterposer::RegisterCurrentThread();
+  mozilla::IOInterposer::RegisterCurrentThread();
 
   // This must come after the call to nsThreadManager::RegisterCurrentThread(),
   // because that call is needed to properly set up this thread as an nsThread,
@@ -448,11 +453,10 @@ void nsThread::ThreadFunc(void* aArg) {
 
   {
     // Scope for MessageLoop.
-    nsAutoPtr<MessageLoop> loop(
-        new MessageLoop(MessageLoop::TYPE_MOZILLA_NONMAINTHREAD, self));
+    MessageLoop loop(MessageLoop::TYPE_MOZILLA_NONMAINTHREAD, self);
 
     // Now, process incoming events...
-    loop->Run();
+    loop.Run();
 
     BackgroundChild::CloseForCurrentThread();
 
@@ -476,7 +480,7 @@ void nsThread::ThreadFunc(void* aArg) {
     }
   }
 
-  //mozilla::IOInterposer::UnregisterCurrentThread();
+  mozilla::IOInterposer::UnregisterCurrentThread();
 
   // Inform the threadmanager that this thread is going away
   nsThreadManager::get().UnregisterCurrentThread(*self);
@@ -599,6 +603,7 @@ nsThread::nsThread(NotNull<SynchronizedEventQueue*> aQueue,
       mShutdownRequired(false),
       mPriority(PRIORITY_NORMAL),
       mIsMainThread(aMainThread == MAIN_THREAD),
+      mIsAPoolThreadFree(nullptr),
       mCanInvokeJS(false),
       mCurrentEvent(nullptr),
       mCurrentEventStart(TimeStamp::Now()),
@@ -641,7 +646,7 @@ nsThread::~nsThread() {
   // requesting shutdown on another, which can be helpful for diagnosing
   // the leak.
   for (size_t i = 0; i < mRequestedShutdownContexts.Length(); ++i) {
-    Unused << mRequestedShutdownContexts[i].forget();
+    Unused << mRequestedShutdownContexts[i].release();
   }
 #endif
 }
@@ -721,6 +726,27 @@ nsThread::DelayedDispatch(already_AddRefed<nsIRunnable> aEvent,
   return mEventTarget->DelayedDispatch(std::move(aEvent), aDelayMs);
 }
 
+NS_IMETHODIMP
+nsThread::GetRunningEventDelay(TimeDuration* aDelay, TimeStamp* aStart) {
+  if (mIsAPoolThreadFree && *mIsAPoolThreadFree) {
+    // if there are unstarted threads in the pool, a new event to the
+    // pool would not be delayed at all (beyond thread start time)
+    *aDelay = TimeDuration();
+    *aStart = TimeStamp();
+  } else {
+    *aDelay = mLastEventDelay;
+    *aStart = mLastEventStart;
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsThread::SetRunningEventDelay(TimeDuration aDelay, TimeStamp aStart) {
+  mLastEventDelay = aDelay;
+  mLastEventStart = aStart;
+  return NS_OK;
+}
+
 NS_IMETHODIMP
 nsThread::IsOnCurrentThread(bool* aResult) {
   if (mEventTarget) {
@@ -802,15 +828,15 @@ nsThreadShutdownContext* nsThread::ShutdownInternal(bool aSync) {
   MOZ_DIAGNOSTIC_ASSERT(currentThread->EventQueue(),
                         "Shutdown() may only be called from an XPCOM thread");
 
-  nsAutoPtr<nsThreadShutdownContext>& context =
-      *currentThread->mRequestedShutdownContexts.AppendElement();
-  context =
+  // Allocate a shutdown context and store a strong ref.
+  auto context =
       new nsThreadShutdownContext(WrapNotNull(this), currentThread, aSync);
+  Unused << *currentThread->mRequestedShutdownContexts.EmplaceBack(context);
 
   // Set mShutdownContext and wake up the thread in case it is waiting for
   // events to process.
   nsCOMPtr<nsIRunnable> event =
-      new nsThreadShutdownEvent(WrapNotNull(this), WrapNotNull(context.get()));
+      new nsThreadShutdownEvent(WrapNotNull(this), WrapNotNull(context));
   // XXXroc What if posting the event fails due to OOM?
   mEvents->PutEvent(event.forget(), EventQueuePriority::Normal);
 
@@ -846,7 +872,8 @@ void nsThread::ShutdownComplete(NotNull<nsThreadShutdownContext*> aContext) {
   // Delete aContext.
   // aContext might not be in mRequestedShutdownContexts if it belongs to a
   // thread that was leaked by calling nsIThreadPool::ShutdownWithTimeout.
-  aContext->mJoiningThread->mRequestedShutdownContexts.RemoveElement(aContext);
+  aContext->mJoiningThread->mRequestedShutdownContexts.RemoveElement(
+      aContext, ShutdownContextsComp{});
 }
 
 void nsThread::WaitForAllAsynchronousShutdowns() {
@@ -1062,6 +1089,7 @@ nsThread::ProcessNextEvent(bool aMayWait, bool* aResult) {
     return NS_OK;
   }
 
+  Maybe<dom::AutoNoJSAPI> noJSAPI;
   if (mIsMainThread) {
     DoMainThreadSpecificProcessing(reallyWait);
   }
@@ -1071,7 +1099,6 @@ nsThread::ProcessNextEvent(bool aMayWait, bool* aResult) {
   // We only want to create an AutoNoJSAPI on threads that actually do DOM stuff
   // (including workers).  Those are exactly the threads that have an
   // mScriptObserver.
-  Maybe<dom::AutoNoJSAPI> noJSAPI;
   bool callScriptObserver = !!mScriptObserver;
   if (callScriptObserver) {
     noJSAPI.emplace();
@@ -1096,7 +1123,8 @@ nsThread::ProcessNextEvent(bool aMayWait, bool* aResult) {
     // mNestedEventLoopDepth has been incremented, since that destructor can
     // also do work.
     EventQueuePriority priority;
-    nsCOMPtr<nsIRunnable> event = mEvents->GetEvent(reallyWait, &priority);
+    nsCOMPtr<nsIRunnable> event =
+        mEvents->GetEvent(reallyWait, &priority, &mLastEventDelay);
 
     *aResult = (event.get() != nullptr);
 
@@ -1107,6 +1135,8 @@ nsThread::ProcessNextEvent(bool aMayWait, bool* aResult) {
       // to run.
       DelayForChaosMode(ChaosFeature::TaskRunning, 1000);
 
+      mozilla::TimeStamp now = mozilla::TimeStamp::Now();
+
       if (mIsMainThread) {
         BackgroundHangMonitor().NotifyActivity();
       }
@@ -1115,7 +1145,7 @@ nsThread::ProcessNextEvent(bool aMayWait, bool* aResult) {
           mCurrentPerformanceCounter) {
         // This is a recursive call, we're saving the time
         // spent in the parent event if the runnable is linked to a DocGroup.
-        mozilla::TimeDuration duration = TimeStamp::Now() - mCurrentEventStart;
+        mozilla::TimeDuration duration = now - mCurrentEventStart;
         mCurrentPerformanceCounter->IncrementExecutionDuration(
             duration.ToMicroseconds());
       }
@@ -1155,10 +1185,10 @@ nsThread::ProcessNextEvent(bool aMayWait, bool* aResult) {
       bool recursiveEvent = mNestedEventLoopDepth > mCurrentEventLoopDepth;
       mCurrentEventLoopDepth = mNestedEventLoopDepth;
       if (mIsMainThread && !recursiveEvent) {
-        mCurrentEventStart = mozilla::TimeStamp::Now();
+        mCurrentEventStart = now;
       }
       RefPtr<mozilla::PerformanceCounter> currentPerformanceCounter;
-      mCurrentEventStart = mozilla::TimeStamp::Now();
+      mLastEventStart = now;
       mCurrentEvent = event;
       mCurrentPerformanceCounter = GetPerformanceCounter(event);
       currentPerformanceCounter = mCurrentPerformanceCounter;
@@ -1178,11 +1208,10 @@ nsThread::ProcessNextEvent(bool aMayWait, bool* aResult) {
           mLastLongTaskEnd = now;
 #ifdef MOZ_GECKO_PROFILER
           if (profiler_thread_is_being_profiled()) {
-            profiler_add_marker(
+            PROFILER_ADD_MARKER_WITH_PAYLOAD(
                 (priority != EventQueuePriority::Idle) ? "LongTask"
                                                        : "LongIdleTask",
-                JS::ProfilingCategoryPair::OTHER,
-                MakeUnique<LongTaskMarkerPayload>(mCurrentEventStart, now));
+                OTHER, LongTaskMarkerPayload, (mCurrentEventStart, now));
           }
 #endif
         }
@@ -1206,9 +1235,14 @@ nsThread::ProcessNextEvent(bool aMayWait, bool* aResult) {
         mCurrentEventLoopDepth = std::numeric_limits<uint32_t>::max();
         mCurrentPerformanceCounter = nullptr;
       }
-    } else if (aMayWait) {
-      MOZ_ASSERT(ShuttingDown(), "This should only happen when shutting down");
-      rv = NS_ERROR_UNEXPECTED;
+    } else {
+      mLastEventDelay = TimeDuration();
+      mLastEventStart = TimeStamp();
+      if (aMayWait) {
+        MOZ_ASSERT(ShuttingDown(),
+                   "This should only happen when shutting down");
+        rv = NS_ERROR_UNEXPECTED;
+      }
     }
   }
 
diff --git a/xpcom/threads/nsThread.h b/xpcom/threads/nsThread.h
index b6cb63342d..20f883245f 100644
--- a/xpcom/threads/nsThread.h
+++ b/xpcom/threads/nsThread.h
@@ -11,13 +11,13 @@
 #include "nsThreadUtils.h"
 #include "nsString.h"
 #include "nsTObserverArray.h"
+#include "mozilla/Atomics.h"
 #include "mozilla/Attributes.h"
 #include "mozilla/LinkedList.h"
 #include "mozilla/MemoryReporting.h"
 #include "mozilla/SynchronizedEventQueue.h"
 #include "mozilla/NotNull.h"
 #include "mozilla/TimeStamp.h"
-#include "nsAutoPtr.h"
 #include "mozilla/AlreadyAddRefed.h"
 #include "mozilla/UniquePtr.h"
 #include "mozilla/Array.h"
@@ -86,6 +86,12 @@ class nsThread : public nsIThreadInternal,
   // nsIThreadManager::NewThread.
   bool ShutdownRequired() { return mShutdownRequired; }
 
+  // Lets GetRunningEventDelay() determine if the pool this is part
+  // of has an unstarted thread
+  void SetPoolThreadFreePtr(mozilla::Atomic<bool, mozilla::Relaxed>* aPtr) {
+    mIsAPoolThreadFree = aPtr;
+  }
+
   void SetScriptObserver(mozilla::CycleCollectedJSContext* aScriptObserver);
 
   uint32_t RecursionDepth() const;
@@ -113,10 +119,6 @@ class nsThread : public nsIThreadInternal,
     EventQueue()->ResumeInputEventPrioritization();
   }
 
-#ifndef RELEASE_OR_BETA
-  mozilla::TimeStamp& NextIdleDeadlineRef() { return mNextIdleDeadline; }
-#endif
-
   mozilla::SynchronizedEventQueue* EventQueue() { return mEvents.get(); }
 
   bool ShuttingDown() { return mShutdownContext != nullptr; }
@@ -202,7 +204,15 @@ class nsThread : public nsIThreadInternal,
   RefPtr<mozilla::ThreadEventTarget> mEventTarget;
 
   // The shutdown contexts for any other threads we've asked to shut down.
-  using ShutdownContexts = nsTArray<nsAutoPtr<struct nsThreadShutdownContext>>;
+  using ShutdownContexts =
+      nsTArray<mozilla::UniquePtr<struct nsThreadShutdownContext>>;
+
+  // Helper for finding a ShutdownContext in the contexts array.
+  struct ShutdownContextsComp {
+    bool Equals(const ShutdownContexts::elem_type& a,
+                const ShutdownContexts::elem_type::Pointer b) const;
+  };
+
   ShutdownContexts mRequestedShutdownContexts;
   // The shutdown context for ourselves.
   struct nsThreadShutdownContext* mShutdownContext;
@@ -224,6 +234,7 @@ class nsThread : public nsIThreadInternal,
   int8_t mPriority;
 
   bool mIsMainThread;
+  mozilla::Atomic<bool, mozilla::Relaxed>* mIsAPoolThreadFree;
 
   // Set to true if this thread creates a JSRuntime.
   bool mCanInvokeJS;
@@ -233,8 +244,16 @@ class nsThread : public nsIThreadInternal,
   // Used to track which event is being executed by ProcessNextEvent
   nsCOMPtr<nsIRunnable> mCurrentEvent;
 
+  // When the current event started.  Note: recursive events use the time
+  // the outmost event started, so the entire recursion chain is considered
+  // one event.
   mozilla::TimeStamp mCurrentEventStart;
-  mozilla::TimeStamp mNextIdleDeadline;
+
+  // The time the currently running event spent in event queues, and
+  // when it started running.  If no event is running, they are
+  // TimeDuration() & TimeStamp().
+  mozilla::TimeDuration mLastEventDelay;
+  mozilla::TimeStamp mLastEventStart;
 
   RefPtr<mozilla::PerformanceCounter> mCurrentPerformanceCounter;
 
diff --git a/xpcom/threads/nsThreadManager.cpp b/xpcom/threads/nsThreadManager.cpp
index 3c80a17f61..cdc769f0c7 100644
--- a/xpcom/threads/nsThreadManager.cpp
+++ b/xpcom/threads/nsThreadManager.cpp
@@ -8,7 +8,6 @@
 #include "nsThreadUtils.h"
 #include "nsIClassInfoImpl.h"
 #include "nsTArray.h"
-#include "nsAutoPtr.h"
 #include "nsXULAppAPI.h"
 #include "MainThreadQueue.h"
 #include "mozilla/AbstractThread.h"
@@ -45,8 +44,8 @@ class BackgroundEventTarget final : public nsIEventTarget {
 
   nsresult Init();
 
-  already_AddRefed<nsISerialEventTarget>
-    CreateBackgroundTaskQueue(const char* aName);
+  already_AddRefed<nsISerialEventTarget> CreateBackgroundTaskQueue(
+      const char* aName);
 
   void BeginShutdown(nsTArray<RefPtr<ShutdownPromise>>&);
   void FinishShutdown();
@@ -64,8 +63,7 @@ class BackgroundEventTarget final : public nsIEventTarget {
 NS_IMPL_ISUPPORTS(BackgroundEventTarget, nsIEventTarget)
 
 BackgroundEventTarget::BackgroundEventTarget()
-    : mMutex("BEvtTgt")
-{}
+    : mMutex("BEvtTgt") {}
 
 nsresult BackgroundEventTarget::Init() {
   nsCOMPtr<nsIThreadPool> pool(new nsThreadPool());
@@ -168,7 +166,8 @@ BackgroundEventTarget::DelayedDispatch(already_AddRefed<nsIRunnable> aRunnable,
   return NS_ERROR_NOT_IMPLEMENTED;
 }
 
-void BackgroundEventTarget::BeginShutdown(nsTArray<RefPtr<ShutdownPromise>>& promises) {
+void BackgroundEventTarget::BeginShutdown(
+    nsTArray<RefPtr<ShutdownPromise>>& promises) {
   for (auto& queue : mTaskQueues) {
     promises.AppendElement(queue->BeginShutdown());
   }
@@ -179,12 +178,13 @@ void BackgroundEventTarget::FinishShutdown() {
   mIOPool->Shutdown();
 }
 
-already_AddRefed<nsISerialEventTarget> BackgroundEventTarget::CreateBackgroundTaskQueue(const char* aName) {
+already_AddRefed<nsISerialEventTarget>
+BackgroundEventTarget::CreateBackgroundTaskQueue(const char* aName) {
   AutoLock lock(mMutex);
 
   RefPtr<TaskQueue> queue = new TaskQueue(do_AddRef(this), aName,
-                                          /*aSupportsTailDispatch=*/ false,
-                                          /*aRetainFlags=*/ true);
+                                          /*aSupportsTailDispatch=*/false,
+                                          /*aRetainFlags=*/true);
   nsCOMPtr<nsISerialEventTarget> target(queue->WrapAsEventTarget());
 
   mTaskQueues.AppendElement(queue.forget());
@@ -424,20 +424,22 @@ void nsThreadManager::Shutdown() {
 
   bool taskQueuesShutdown = false;
 
-  complete->Then(mMainThread, __func__,
-                 [&](const ResolveValueT& aResolveValue) {
-                   mBackgroundEventTarget->FinishShutdown();
-                   taskQueuesShutdown = true;
-                 },
-                 [&](RejectValueT aRejectValue) {
-                   mBackgroundEventTarget->FinishShutdown();
-                   taskQueuesShutdown = true;
-                 });
+  complete->Then(
+      mMainThread, __func__,
+      [&](const ResolveValueT& aResolveValue) {
+        mBackgroundEventTarget->FinishShutdown();
+        taskQueuesShutdown = true;
+      },
+      [&](RejectValueT aRejectValue) {
+        mBackgroundEventTarget->FinishShutdown();
+        taskQueuesShutdown = true;
+      });
 
-  // Wait for task queues to shutdown, so we don't shut down the underlying threads
-  // of the background event target in the block below, thereby preventing the task
-  // queues from emptying, preventing the shutdown promises from resolving, and
-  // prevent anything checking `taskQueuesShutdown` from working.
+  // Wait for task queues to shutdown, so we don't shut down the underlying
+  // threads of the background event target in the block below, thereby
+  // preventing the task queues from emptying, preventing the shutdown promises
+  // from resolving, and prevent anything checking `taskQueuesShutdown` from
+  // working.
   ::SpinEventLoopUntil([&]() { return taskQueuesShutdown; }, mMainThread);
 
   {
@@ -550,7 +552,8 @@ nsresult nsThreadManager::DispatchToBackgroundThread(nsIRunnable* aEvent,
   return backgroundTarget->Dispatch(aEvent, aDispatchFlags);
 }
 
-already_AddRefed<nsISerialEventTarget> nsThreadManager::CreateBackgroundTaskQueue(const char* aName) {
+already_AddRefed<nsISerialEventTarget>
+nsThreadManager::CreateBackgroundTaskQueue(const char* aName) {
   if (!mInitialized) {
     return nullptr;
   }
diff --git a/xpcom/threads/nsThreadPool.cpp b/xpcom/threads/nsThreadPool.cpp
index e5e5624b77..f21d33a95c 100644
--- a/xpcom/threads/nsThreadPool.cpp
+++ b/xpcom/threads/nsThreadPool.cpp
@@ -9,7 +9,6 @@
 #include "nsThreadManager.h"
 #include "nsThread.h"
 #include "nsMemory.h"
-#include "nsAutoPtr.h"
 #include "prinrval.h"
 #include "mozilla/Logging.h"
 #include "mozilla/SystemGroup.h"
@@ -50,7 +49,8 @@ nsThreadPool::nsThreadPool()
       mIdleCount(0),
       mStackSize(nsIThreadManager::DEFAULT_STACK_SIZE),
       mShutdown(false),
-      mRegressiveMaxIdleTime(false) {
+      mRegressiveMaxIdleTime(false),
+      mIsAPoolThreadFree(true) {
   LOG(("THRD-P(%p) constructor!!!\n", this));
 }
 
@@ -119,7 +119,11 @@ nsresult nsThreadPool::PutEvent(already_AddRefed<nsIRunnable> aEvent,
       killThread = true;
     } else if (mThreads.Count() < (int32_t)mThreadLimit) {
       mThreads.AppendObject(thread);
+      if (mThreads.Count() >= (int32_t)mThreadLimit) {
+        mIsAPoolThreadFree = false;
+      }
     } else {
+      // Someone else may have also been starting a thread
       killThread = true;  // okay, we don't need this thread anymore
     }
   }
@@ -153,6 +157,35 @@ void nsThreadPool::ShutdownThread(nsIThread* aThread) {
                                           &nsIThread::AsyncShutdown));
 }
 
+// This event 'runs' for the lifetime of the worker thread.  The actual
+// eventqueue is mEvents, and is shared by all the worker threads.  This
+// means that the set of threads together define the delay seen by a new
+// event sent to the pool.
+//
+// To model the delay experienced by the pool, we can have each thread in
+// the pool report 0 if it's idle OR if the pool is below the threadlimit;
+// or otherwise the current event's queuing delay plus current running
+// time.
+//
+// To reconstruct the delays for the pool, the profiler can look at all the
+// threads that are part of a pool (pools have defined naming patterns that
+// can be user to connect them).  If all threads have delays at time X,
+// that means that all threads saturated at that point and any event
+// dispatched to the pool would get a delay.
+//
+// The delay experienced by an event dispatched when all pool threads are
+// busy is based on the calculations shown in platform.cpp.  Run that
+// algorithm for each thread in the pool, and the delay at time X is the
+// longest value for time X of any of the threads, OR the time from X until
+// any one of the threads reports 0 (i.e. it's not busy), whichever is
+// shorter.
+
+// In order to record this when the profiler samples threads in the pool,
+// each thread must (effectively) override GetRunnningEventDelay, by
+// resetting the mLastEventDelay/Start values in the nsThread when we start
+// to run an event (or when we run out of events to run).  Note that handling
+// the shutdown of a thread may be a little tricky.
+
 NS_IMETHODIMP
 nsThreadPool::Run() {
   LOG(("THRD-P(%p) enter %s\n", this, mName.BeginReading()));
@@ -165,6 +198,10 @@ nsThreadPool::Run() {
   bool wasIdle = false;
   TimeStamp idleSince;
 
+  // This thread is an nsThread created below with NS_NewNamedThread()
+  static_cast<nsThread*>(current.get())
+      ->SetPoolThreadFreePtr(&mIsAPoolThreadFree);
+
   nsCOMPtr<nsIThreadPoolListener> listener;
   {
     AutoLock lock(mMutex);
@@ -177,10 +214,11 @@ nsThreadPool::Run() {
 
   do {
     nsCOMPtr<nsIRunnable> event;
+    TimeDuration delay;
     {
       AutoLock lock(mMutex);
 
-      event = mEvents.GetEvent(nullptr, lock);
+      event = mEvents.GetEvent(nullptr, lock, &delay);
       if (!event) {
         TimeStamp now = TimeStamp::Now();
         uint32_t idleTimeoutDivider =
@@ -216,7 +254,12 @@ nsThreadPool::Run() {
             --mIdleCount;
           }
           shutdownThreadOnExit = mThreads.RemoveObject(current);
+
+          // keep track if there are threads available to start
+          mIsAPoolThreadFree = (mThreads.Count() < (int32_t)mThreadLimit);
         } else {
+          current->SetRunningEventDelay(TimeDuration(), TimeStamp());
+
           AUTO_PROFILER_LABEL("nsThreadPool::Run::Wait", IDLE);
 
           TimeDuration delta = timeout - (now - idleSince);
@@ -241,6 +284,10 @@ nsThreadPool::Run() {
       // to run.
       DelayForChaosMode(ChaosFeature::TaskRunning, 1000);
 
+      // We'll handle the case of unstarted threads available
+      // when we sample.
+      current->SetRunningEventDelay(delay, TimeStamp::Now());
+
       event->Run();
     }
   } while (!exitThread);
@@ -430,17 +477,18 @@ nsThreadPool::ShutdownWithTimeout(int32_t aTimeoutMs) {
   // For any threads that have not shutdown yet, we need to remove them from
   // mRequestedShutdownContexts so the thread manager does not wait for them
   // at shutdown.
+  static const nsThread::ShutdownContextsComp comparator{};
   for (int32_t i = 0; i < threads.Count(); ++i) {
     nsThread* thread = static_cast<nsThread*>(threads[i]);
     // If mThread is not null on the thread it means that it hasn't shutdown
     // context[i] corresponds to thread[i]
     if (thread->mThread && contexts[i]) {
-      auto index =
-          currentThread->mRequestedShutdownContexts.IndexOf(contexts[i]);
+      auto index = currentThread->mRequestedShutdownContexts.IndexOf(
+          contexts[i], 0, comparator);
       if (index != nsThread::ShutdownContexts::NoIndex) {
         // We must leak the shutdown context just in case the leaked thread
         // does get unstuck and completes before the main thread is done.
-        currentThread->mRequestedShutdownContexts[index].forget();
+        Unused << currentThread->mRequestedShutdownContexts[index].release();
         currentThread->mRequestedShutdownContexts.RemoveElementsAt(index, 1);
       }
     }
diff --git a/xpcom/threads/nsThreadPool.h b/xpcom/threads/nsThreadPool.h
index 3f9d12d9c8..4dcc491656 100644
--- a/xpcom/threads/nsThreadPool.h
+++ b/xpcom/threads/nsThreadPool.h
@@ -11,6 +11,7 @@
 #include "nsCOMArray.h"
 #include "nsCOMPtr.h"
 #include "nsThreadUtils.h"
+#include "mozilla/Atomics.h"
 #include "mozilla/Attributes.h"
 #include "mozilla/AlreadyAddRefed.h"
 #include "mozilla/EventQueue.h"
@@ -45,6 +46,7 @@ class nsThreadPool final : public nsIThreadPool, public nsIRunnable {
   nsCOMPtr<nsIThreadPoolListener> mListener;
   bool mShutdown;
   bool mRegressiveMaxIdleTime;
+  mozilla::Atomic<bool, mozilla::Relaxed> mIsAPoolThreadFree;
   nsCString mName;
   nsThreadPoolNaming mThreadNaming;
 };
diff --git a/xpcom/threads/nsThreadUtils.h b/xpcom/threads/nsThreadUtils.h
index c0bdafe92d..0ae0ec9149 100644
--- a/xpcom/threads/nsThreadUtils.h
+++ b/xpcom/threads/nsThreadUtils.h
@@ -16,7 +16,6 @@
 #include "mozilla/TimeStamp.h"
 #include "mozilla/Tuple.h"
 #include "mozilla/TypeTraits.h"
-#include "nsAutoPtr.h"
 #include "nsCOMPtr.h"
 #include "nsICancelableRunnable.h"
 #include "nsIIdlePeriod.h"
@@ -568,7 +567,7 @@ class RunnableFunction : public Runnable {
 template <typename Function>
 using RunnableFunctionImpl =
     // Make sure we store a non-reference in nsRunnableFunction.
-    typename detail::RunnableFunction<typename RemoveReference<Function>::Type>;
+    typename detail::RunnableFunction<std::remove_reference_t<Function>>;
 }  // namespace detail
 
 namespace detail {
@@ -700,17 +699,16 @@ class TimerBehaviour<RunnableKind::IdleWithTimer> {
 template <class ClassType, typename ReturnType = void, bool Owning = true,
           mozilla::RunnableKind Kind = mozilla::RunnableKind::Standard>
 class nsRunnableMethod
-    : public mozilla::Conditional<
+    : public std::conditional_t<
           Kind == mozilla::RunnableKind::Standard, mozilla::Runnable,
-          typename mozilla::Conditional<
-              Kind == mozilla::RunnableKind::Cancelable,
-              mozilla::CancelableRunnable, mozilla::IdleRunnable>::Type>::Type,
+          std::conditional_t<Kind == mozilla::RunnableKind::Cancelable,
+                             mozilla::CancelableRunnable,
+                             mozilla::IdleRunnable>>,
       protected mozilla::detail::TimerBehaviour<Kind> {
-  using BaseType = typename mozilla::Conditional<
+  using BaseType = std::conditional_t<
       Kind == mozilla::RunnableKind::Standard, mozilla::Runnable,
-      typename mozilla::Conditional<Kind == mozilla::RunnableKind::Cancelable,
-                                    mozilla::CancelableRunnable,
-                                    mozilla::IdleRunnable>::Type>::Type;
+      std::conditional_t<Kind == mozilla::RunnableKind::Cancelable,
+                         mozilla::CancelableRunnable, mozilla::IdleRunnable>>;
 
  public:
   nsRunnableMethod(const char* aName) : BaseType(aName) {}
@@ -997,8 +995,8 @@ struct SFINAE1True : mozilla::TrueType {};
 
 template <class T>
 static auto HasRefCountMethodsTest(int)
-    -> SFINAE1True<decltype(mozilla::DeclVal<T>().AddRef(),
-                            mozilla::DeclVal<T>().Release())>;
+    -> SFINAE1True<decltype(std::declval<T>().AddRef(),
+                            std::declval<T>().Release())>;
 template <class>
 static auto HasRefCountMethodsTest(long) -> mozilla::FalseType;
 
@@ -1007,55 +1005,66 @@ struct HasRefCountMethods : decltype(HasRefCountMethodsTest<T>(0)) {};
 
 template <typename TWithoutPointer>
 struct NonnsISupportsPointerStorageClass
-    : mozilla::Conditional<
+    : std::conditional<
           std::is_const_v<TWithoutPointer>,
           StoreConstPtrPassByConstPtr<
               typename mozilla::RemoveConst<TWithoutPointer>::Type>,
-          StorePtrPassByPtr<TWithoutPointer>> {};
+          StorePtrPassByPtr<TWithoutPointer>> {
+  using Type = typename NonnsISupportsPointerStorageClass::conditional::type;
+};
 
 template <typename TWithoutPointer>
 struct PointerStorageClass
-    : mozilla::Conditional<
+    : std::conditional<
           HasRefCountMethods<TWithoutPointer>::value,
           StoreRefPtrPassByPtr<TWithoutPointer>,
-          typename NonnsISupportsPointerStorageClass<TWithoutPointer>::Type> {};
+          typename NonnsISupportsPointerStorageClass<TWithoutPointer>::Type> {
+  using Type = typename PointerStorageClass::conditional::type;
+};
 
 template <typename TWithoutRef>
 struct LValueReferenceStorageClass
-    : mozilla::Conditional<
-          std::is_const_v<TWithoutRef>,
-          StoreConstRefPassByConstLRef<
-              typename mozilla::RemoveConst<TWithoutRef>::Type>,
-          StoreRefPassByLRef<TWithoutRef>> {};
+    : std::conditional<std::is_const_v<TWithoutRef>,
+                       StoreConstRefPassByConstLRef<
+                           typename mozilla::RemoveConst<TWithoutRef>::Type>,
+                       StoreRefPassByLRef<TWithoutRef>> {
+  using Type = typename LValueReferenceStorageClass::conditional::type;
+};
 
 template <typename T>
 struct SmartPointerStorageClass
-    : mozilla::Conditional<
+    : std::conditional<
           mozilla::IsRefcountedSmartPointer<T>::value,
           StoreRefPtrPassByPtr<typename mozilla::RemoveSmartPointer<T>::Type>,
-          StoreCopyPassByConstLRef<T>> {};
+          StoreCopyPassByConstLRef<T>> {
+  using Type = typename SmartPointerStorageClass::conditional::type;
+};
 
 template <typename T>
 struct NonLValueReferenceStorageClass
-    : mozilla::Conditional<
-          std::is_rvalue_reference_v<T>,
-          StoreCopyPassByRRef<typename mozilla::RemoveReference<T>::Type>,
-          typename SmartPointerStorageClass<T>::Type> {};
+    : std::conditional<std::is_rvalue_reference_v<T>,
+                       StoreCopyPassByRRef<std::remove_reference_t<T>>,
+                       typename SmartPointerStorageClass<T>::Type> {
+  using Type = typename NonLValueReferenceStorageClass::conditional::type;
+};
 
 template <typename T>
 struct NonPointerStorageClass
-    : mozilla::Conditional<
-          std::is_lvalue_reference_v<T>,
-          typename LValueReferenceStorageClass<
-              typename mozilla::RemoveReference<T>::Type>::Type,
-          typename NonLValueReferenceStorageClass<T>::Type> {};
+    : std::conditional<std::is_lvalue_reference_v<T>,
+                       typename LValueReferenceStorageClass<
+                           std::remove_reference_t<T>>::Type,
+                       typename NonLValueReferenceStorageClass<T>::Type> {
+  using Type = typename NonPointerStorageClass::conditional::type;
+};
 
 template <typename T>
 struct NonParameterStorageClass
-    : mozilla::Conditional<std::is_pointer_v<T>,
-                           typename PointerStorageClass<
-                               typename mozilla::RemovePointer<T>::Type>::Type,
-                           typename NonPointerStorageClass<T>::Type> {};
+    : std::conditional<
+          std::is_pointer_v<T>,
+          typename PointerStorageClass<std::remove_pointer_t<T>>::Type,
+          typename NonPointerStorageClass<T>::Type> {
+  using Type = typename NonParameterStorageClass::conditional::type;
+};
 
 // Choose storage&passing strategy based on preferred storage type:
 // - If IsParameterStorageClass<T>::value is true, use as-is.
@@ -1078,12 +1087,14 @@ struct NonParameterStorageClass
 // clean-up in destructor, and with associated IsParameterStorageClass<>.
 template <typename T>
 struct ParameterStorage
-    : mozilla::Conditional<IsParameterStorageClass<T>::value, T,
-                           typename NonParameterStorageClass<T>::Type> {};
+    : std::conditional<IsParameterStorageClass<T>::value, T,
+                       typename NonParameterStorageClass<T>::Type> {
+  using Type = typename ParameterStorage::conditional::type;
+};
 
 template <class T>
 static auto HasSetDeadlineTest(int) -> SFINAE1True<decltype(
-    mozilla::DeclVal<T>().SetDeadline(mozilla::DeclVal<mozilla::TimeStamp>()))>;
+    std::declval<T>().SetDeadline(std::declval<mozilla::TimeStamp>()))>;
 
 template <class T>
 static auto HasSetDeadlineTest(long) -> mozilla::FalseType;
@@ -1092,14 +1103,14 @@ template <class T>
 struct HasSetDeadline : decltype(HasSetDeadlineTest<T>(0)) {};
 
 template <class T>
-typename mozilla::EnableIf<::detail::HasSetDeadline<T>::value>::Type
-SetDeadlineImpl(T* aObj, mozilla::TimeStamp aTimeStamp) {
+std::enable_if_t<::detail::HasSetDeadline<T>::value> SetDeadlineImpl(
+    T* aObj, mozilla::TimeStamp aTimeStamp) {
   aObj->SetDeadline(aTimeStamp);
 }
 
 template <class T>
-typename mozilla::EnableIf<!::detail::HasSetDeadline<T>::value>::Type
-SetDeadlineImpl(T* aObj, mozilla::TimeStamp aTimeStamp) {}
+std::enable_if_t<!::detail::HasSetDeadline<T>::value> SetDeadlineImpl(
+    T* aObj, mozilla::TimeStamp aTimeStamp) {}
 } /* namespace detail */
 
 namespace mozilla {
@@ -1207,89 +1218,85 @@ class RunnableMethodImpl final
 // Type aliases for NewRunnableMethod.
 template <typename PtrType, typename Method>
 using OwningRunnableMethod =
-    typename ::nsRunnableMethodTraits<typename RemoveReference<PtrType>::Type,
-                                      Method, true,
-                                      RunnableKind::Standard>::base_type;
+    typename ::nsRunnableMethodTraits<std::remove_reference_t<PtrType>, Method,
+                                      true, RunnableKind::Standard>::base_type;
 template <typename PtrType, typename Method, typename... Storages>
 using OwningRunnableMethodImpl =
-    RunnableMethodImpl<typename RemoveReference<PtrType>::Type, Method, true,
+    RunnableMethodImpl<std::remove_reference_t<PtrType>, Method, true,
                        RunnableKind::Standard, Storages...>;
 
 // Type aliases for NewCancelableRunnableMethod.
 template <typename PtrType, typename Method>
 using CancelableRunnableMethod =
-    typename ::nsRunnableMethodTraits<typename RemoveReference<PtrType>::Type,
-                                      Method, true,
+    typename ::nsRunnableMethodTraits<std::remove_reference_t<PtrType>, Method,
+                                      true,
                                       RunnableKind::Cancelable>::base_type;
 template <typename PtrType, typename Method, typename... Storages>
 using CancelableRunnableMethodImpl =
-    RunnableMethodImpl<typename RemoveReference<PtrType>::Type, Method, true,
+    RunnableMethodImpl<std::remove_reference_t<PtrType>, Method, true,
                        RunnableKind::Cancelable, Storages...>;
 
 // Type aliases for NewIdleRunnableMethod.
 template <typename PtrType, typename Method>
 using IdleRunnableMethod =
-    typename ::nsRunnableMethodTraits<typename RemoveReference<PtrType>::Type,
-                                      Method, true,
-                                      RunnableKind::Idle>::base_type;
+    typename ::nsRunnableMethodTraits<std::remove_reference_t<PtrType>, Method,
+                                      true, RunnableKind::Idle>::base_type;
 template <typename PtrType, typename Method, typename... Storages>
 using IdleRunnableMethodImpl =
-    RunnableMethodImpl<typename RemoveReference<PtrType>::Type, Method, true,
+    RunnableMethodImpl<std::remove_reference_t<PtrType>, Method, true,
                        RunnableKind::Idle, Storages...>;
 
 // Type aliases for NewIdleRunnableMethodWithTimer.
 template <typename PtrType, typename Method>
 using IdleRunnableMethodWithTimer =
-    typename ::nsRunnableMethodTraits<typename RemoveReference<PtrType>::Type,
-                                      Method, true,
+    typename ::nsRunnableMethodTraits<std::remove_reference_t<PtrType>, Method,
+                                      true,
                                       RunnableKind::IdleWithTimer>::base_type;
 template <typename PtrType, typename Method, typename... Storages>
 using IdleRunnableMethodWithTimerImpl =
-    RunnableMethodImpl<typename RemoveReference<PtrType>::Type, Method, true,
+    RunnableMethodImpl<std::remove_reference_t<PtrType>, Method, true,
                        RunnableKind::IdleWithTimer, Storages...>;
 
 // Type aliases for NewNonOwningRunnableMethod.
 template <typename PtrType, typename Method>
 using NonOwningRunnableMethod =
-    typename ::nsRunnableMethodTraits<typename RemoveReference<PtrType>::Type,
-                                      Method, false,
-                                      RunnableKind::Standard>::base_type;
+    typename ::nsRunnableMethodTraits<std::remove_reference_t<PtrType>, Method,
+                                      false, RunnableKind::Standard>::base_type;
 template <typename PtrType, typename Method, typename... Storages>
 using NonOwningRunnableMethodImpl =
-    RunnableMethodImpl<typename RemoveReference<PtrType>::Type, Method, false,
+    RunnableMethodImpl<std::remove_reference_t<PtrType>, Method, false,
                        RunnableKind::Standard, Storages...>;
 
 // Type aliases for NonOwningCancelableRunnableMethod
 template <typename PtrType, typename Method>
 using NonOwningCancelableRunnableMethod =
-    typename ::nsRunnableMethodTraits<typename RemoveReference<PtrType>::Type,
-                                      Method, false,
+    typename ::nsRunnableMethodTraits<std::remove_reference_t<PtrType>, Method,
+                                      false,
                                       RunnableKind::Cancelable>::base_type;
 template <typename PtrType, typename Method, typename... Storages>
 using NonOwningCancelableRunnableMethodImpl =
-    RunnableMethodImpl<typename RemoveReference<PtrType>::Type, Method, false,
+    RunnableMethodImpl<std::remove_reference_t<PtrType>, Method, false,
                        RunnableKind::Cancelable, Storages...>;
 
 // Type aliases for NonOwningIdleRunnableMethod
 template <typename PtrType, typename Method>
 using NonOwningIdleRunnableMethod =
-    typename ::nsRunnableMethodTraits<typename RemoveReference<PtrType>::Type,
-                                      Method, false,
-                                      RunnableKind::Idle>::base_type;
+    typename ::nsRunnableMethodTraits<std::remove_reference_t<PtrType>, Method,
+                                      false, RunnableKind::Idle>::base_type;
 template <typename PtrType, typename Method, typename... Storages>
 using NonOwningIdleRunnableMethodImpl =
-    RunnableMethodImpl<typename RemoveReference<PtrType>::Type, Method, false,
+    RunnableMethodImpl<std::remove_reference_t<PtrType>, Method, false,
                        RunnableKind::Idle, Storages...>;
 
 // Type aliases for NewIdleRunnableMethodWithTimer.
 template <typename PtrType, typename Method>
 using NonOwningIdleRunnableMethodWithTimer =
-    typename ::nsRunnableMethodTraits<typename RemoveReference<PtrType>::Type,
-                                      Method, false,
+    typename ::nsRunnableMethodTraits<std::remove_reference_t<PtrType>, Method,
+                                      false,
                                       RunnableKind::IdleWithTimer>::base_type;
 template <typename PtrType, typename Method, typename... Storages>
 using NonOwningIdleRunnableMethodWithTimerImpl =
-    RunnableMethodImpl<typename RemoveReference<PtrType>::Type, Method, false,
+    RunnableMethodImpl<std::remove_reference_t<PtrType>, Method, false,
                        RunnableKind::IdleWithTimer, Storages...>;
 
 }  // namespace detail
diff --git a/xpcom/threads/nsTimerImpl.cpp b/xpcom/threads/nsTimerImpl.cpp
index d8cce6f31d..038e245b42 100644
--- a/xpcom/threads/nsTimerImpl.cpp
+++ b/xpcom/threads/nsTimerImpl.cpp
@@ -4,7 +4,6 @@
 
 #include "nsTimerImpl.h"
 #include "TimerThread.h"
-#include "nsAutoPtr.h"
 #include "nsThreadManager.h"
 #include "nsThreadUtils.h"
 #include "pratom.h"
diff --git a/xpfe/appshell/components.conf b/xpfe/appshell/components.conf
index 78322433d4..17673cd60f 100644
--- a/xpfe/appshell/components.conf
+++ b/xpfe/appshell/components.conf
@@ -4,14 +4,18 @@
 
 Classes = [
     {
+        'js_name': 'appShell',
         'cid': '{0099907d-123c-4853-a46a-43098b5fb68c}',
         'contract_ids': ['@mozilla.org/appshell/appShellService;1'],
+        'interfaces': ['nsIAppShellService'],
         'type': 'nsAppShellService',
         'headers': ['/xpfe/appshell/nsAppShellService.h'],
     },
     {
+        'js_name': 'wm',
         'cid': '{79a2b7cc-f05b-4605-bfa0-fac54f27eec8}',
         'contract_ids': ['@mozilla.org/appshell/window-mediator;1'],
+        'interfaces': ['nsIWindowMediator'],
         'type': 'nsWindowMediator',
         'headers': ['/xpfe/appshell/nsWindowMediator.h'],
         'init_method': 'Init',