Merge mozilla-central to mozilla-inbound

2024-10-08 02:14:43 +00:00 · 2017-03-13 15:25:16 +01:00 · 2017-03-13 15:25:16 +01:00 · e078579f28
commit e078579f28
parent 9201f186e0 c1edc7067d
233 changed files with 21806 additions and 19412 deletions
--- a/browser/base/content/test/plugins/browser.ini
+++ b/browser/base/content/test/plugins/browser.ini
@ -39,35 +39,56 @@ support-files =
  plugin_zoom.html

 [browser_bug743421.js]
+tags = blocklist
 [browser_bug744745.js]
 [browser_bug787619.js]
 [browser_bug797677.js]
 [browser_bug812562.js]
+tags = blocklist
 [browser_bug818118.js]
 [browser_bug820497.js]
 [browser_clearplugindata.js]
+tags = blocklist
 [browser_CTP_context_menu.js]
 skip-if = toolkit == "gtk2" || toolkit == "gtk3"   # fails intermittently on Linux (bug 909342)
+tags = blocklist
 [browser_CTP_crashreporting.js]
 skip-if = !crashreporter
+tags = blocklist
 [browser_CTP_data_urls.js]
+tags = blocklist
 [browser_CTP_drag_drop.js]
+tags = blocklist
 [browser_CTP_hide_overlay.js]
+tags = blocklist
 [browser_CTP_iframe.js]
+tags = blocklist
 [browser_CTP_multi_allow.js]
+tags = blocklist
 [browser_CTP_nonplugins.js]
+tags = blocklist
 [browser_CTP_notificationBar.js]
+tags = blocklist
 [browser_CTP_outsideScrollArea.js]
+tags = blocklist
 [browser_CTP_remove_navigate.js]
+tags = blocklist
 [browser_CTP_resize.js]
+tags = blocklist
 [browser_CTP_zoom.js]
+tags = blocklist
 [browser_blocking.js]
+tags = blocklist
 [browser_iterate_hidden_plugins.js]
 [browser_plugins_added_dynamically.js]
+tags = blocklist
 [browser_pluginnotification.js]
+tags = blocklist
 [browser_plugin_reloading.js]
+tags = blocklist
 [browser_blocklist_content.js]
 skip-if = !e10s
+tags = blocklist
 [browser_globalplugin_crashinfobar.js]
 skip-if = !crashreporter
 [browser_pluginCrashCommentAndURL.js]
--- a/browser/base/content/test/social/browser.ini
+++ b/browser/base/content/test/social/browser.ini
@ -19,5 +19,6 @@ support-files =
 [browser_aboutHome_activation.js]
 [browser_addons.js]
 [browser_blocklist.js]
+tags = blocklist
 [browser_share.js]
 [browser_social_activation.js]
--- a/browser/base/content/test/webextensions/browser.ini
+++ b/browser/base/content/test/webextensions/browser.ini
@ -6,6 +6,7 @@ support-files =
  browser_legacy_webext.xpi
  browser_webext_permissions.xpi
  browser_webext_nopermissions.xpi
+  browser_webext_unsigned.xpi
  browser_webext_update1.xpi
  browser_webext_update2.xpi
  browser_webext_update_icon1.xpi
@ -21,5 +22,7 @@ support-files =
 [browser_permissions_installTrigger.js]
 [browser_permissions_local_file.js]
 [browser_permissions_mozAddonManager.js]
+[browser_permissions_unsigned.js]
+skip-if = require_signing
 [browser_update_interactive.js]
 [browser_update_interactive_noprompt.js]
--- a/browser/base/content/test/webextensions/browser_permissions_unsigned.js
+++ b/browser/base/content/test/webextensions/browser_permissions_unsigned.js
@ -0,0 +1,44 @@
+"use strict";
+
+const ID = "permissions@test.mozilla.org";
+const WARNING_ICON = "chrome://browser/skin/warning.svg";
+
+add_task(async function test_unsigned() {
+  await SpecialPowers.pushPrefEnv({set: [
+    ["extensions.webapi.testing", true],
+    ["extensions.install.requireBuiltInCerts", false],
+
+    // XXX remove this when prompts are enabled by default
+    ["extensions.webextPermissionPrompts", true],
+  ]});
+
+  let testURI = makeURI("https://example.com/");
+  Services.perms.add(testURI, "install", Services.perms.ALLOW_ACTION);
+  registerCleanupFunction(() => Services.perms.remove(testURI, "install"));
+
+  let tab = await BrowserTestUtils.openNewForegroundTab(gBrowser);
+
+  gBrowser.selectedBrowser.loadURI(`${BASE}/file_install_extensions.html`);
+  await BrowserTestUtils.browserLoaded(gBrowser.selectedBrowser);
+
+  ContentTask.spawn(gBrowser.selectedBrowser, `${BASE}/browser_webext_unsigned.xpi`, function*(url) {
+    content.wrappedJSObject.installTrigger(url);
+  });
+
+  let panel = await promisePopupNotificationShown("addon-webext-permissions");
+
+  is(panel.getAttribute("icon"), WARNING_ICON);
+  checkPermissionString(document.getElementById("addon-webext-perm-text").textContent,
+                        "webextPerms.unsignedWarning", null,
+                        "Install notification includes unsigned warning");
+
+  // cancel the install
+  let promise = promiseInstallEvent({id: ID}, "onInstallCancelled");
+  panel.secondaryButton.click();
+  await promise;
+
+  let addon = await AddonManager.getAddonByID(ID);
+  is(addon, null, "Extension is not installed");
+
+  await BrowserTestUtils.removeTab(tab);
+});
--- a/browser/base/content/test/webextensions/browser_webext_unsigned.xpi
+++ b/browser/base/content/test/webextensions/browser_webext_unsigned.xpi
--- a/browser/locales/en-US/chrome/browser/browser.properties
+++ b/browser/locales/en-US/chrome/browser/browser.properties
@ -41,6 +41,8 @@ xpinstallDisabledButton.accesskey=n
 # Note, this string will be used as raw markup. Avoid characters like <, >, &
 webextPerms.header=Add %S?

+webextPerms.unsignedWarning=Caution: This add-on is unverified. Malicious add-ons can steal your private information or compromise your computer. Only install this add-on if you trust the source.
+
 # LOCALIZATION NOTE (webextPerms.listIntro)
 # This string will be followed by a list of permissions requested
 # by the webextension.
--- a/browser/modules/ExtensionsUI.jsm
+++ b/browser/modules/ExtensionsUI.jsm
@ -144,13 +144,17 @@ this.ExtensionsUI = {
        progressNotification.remove();
      }

+      info.unsigned = info.addon.signedState <= AddonManager.SIGNEDSTATE_MISSING;
      let strings = this._buildStrings(info);
+
      // If this is an update with no promptable permissions, just apply it
      if (info.type == "update" && strings.msgs.length == 0) {
        info.resolve();
        return;
      }

+      let icon = info.unsigned ? "chrome://browser/skin/warning.svg" : info.icon;
+
      let histkey;
      if (info.type == "sideload") {
        histkey = "sideload";
@ -164,7 +168,7 @@ this.ExtensionsUI = {
        histkey = "installWeb";
      }

-      this.showPermissionsPrompt(target, strings, info.icon, histkey)
+      this.showPermissionsPrompt(target, strings, icon, histkey)
          .then(answer => {
            if (answer) {
              info.resolve();
@ -298,7 +302,8 @@ this.ExtensionsUI = {
    let addonName = `<span class="addon-webext-name">${name}</span>`;

    result.header = bundle.formatStringFromName("webextPerms.header", [addonName], 1);
-    result.text = "";
+    result.text = info.unsigned ?
+                  bundle.GetStringFromName("webextPerms.unsignedWarning") : "";
    result.listIntro = bundle.GetStringFromName("webextPerms.listIntro");

    result.acceptText = bundle.GetStringFromName("webextPerms.add.label");
--- a/browser/modules/SelfSupportBackend.jsm
+++ b/browser/modules/SelfSupportBackend.jsm
@ -80,7 +80,7 @@ var SelfSupportBackendInternal = {

    this._log.trace("init");

-    Preferences.observe(PREF_BRANCH_LOG, this._configureLogging, this);
+    Services.prefs.addObserver(PREF_BRANCH_LOG, this, false);

    // Only allow to use SelfSupport if Unified Telemetry is enabled.
    let reportingEnabled = IS_UNIFIED_TELEMETRY;
@ -111,7 +111,7 @@ var SelfSupportBackendInternal = {
  uninit() {
    this._log.trace("uninit");

-    Preferences.ignore(PREF_BRANCH_LOG, this._configureLogging, this);
+    Services.prefs.removeObserver(PREF_BRANCH_LOG, this);

    // Cancel delayed loading, if still active, when shutting down.
    clearTimeout(this._delayedLoadTimerId);
@ -148,6 +148,8 @@ var SelfSupportBackendInternal = {
    if (aTopic === "sessionstore-windows-restored") {
      Services.obs.removeObserver(this, "sessionstore-windows-restored");
      this._delayedLoadTimerId = setTimeout(this._loadSelfSupport.bind(this), STARTUP_DELAY_MS);
+    } else if (aTopic === "nsPref:changed") {
+      this._configureLogging();
    }
  },

--- a/browser/themes/osx/browser.css
+++ b/browser/themes/osx/browser.css
@ -1490,14 +1490,7 @@ toolbar .toolbarbutton-1 > .toolbarbutton-menubutton-button {
 #urlbar[focused="true"],
 .searchbar-textbox[focused="true"] {
  border-color: -moz-mac-focusring;
-  box-shadow: @focusRingShadow@;
-}
-
-@media (-moz-mac-yosemite-theme) {
-  #urlbar[focused="true"],
-  .searchbar-textbox[focused="true"] {
-    box-shadow: @yosemiteFocusRingShadow@;
-  }
+  box-shadow: var(--focus-ring-box-shadow);
 }

 #urlbar-container {
@ -1572,8 +1565,7 @@ toolbar .toolbarbutton-1 > .toolbarbutton-menubutton-button {
 }

 #identity-box:-moz-focusring {
-  box-shadow: 0 0 2px 1px -moz-mac-focusring inset,
-              0 0 2px 2px -moz-mac-focusring;
+  box-shadow: var(--focus-ring-box-shadow);
  border-inline-end-style: none;
  padding-inline-end: 5px;
 }
@ -2070,7 +2062,7 @@ html|span.ac-emphasize-text-url {
 #editBMPanel_rows > row > textbox[focused="true"],
 #editBMPanel_rows > row > hbox > textbox[focused="true"] {
  border-color: -moz-mac-focusring !important;
-  box-shadow: @focusRingShadow@;
+  box-shadow: var(--focus-ring-box-shadow);
 }

 /**** HUD style buttons ****/
@ -2090,7 +2082,7 @@ html|span.ac-emphasize-text-url {

 .editBookmarkPanelHeaderButton:-moz-focusring,
 .editBookmarkPanelBottomButton:-moz-focusring {
-  @hudButtonFocused@
+  box-shadow: var(--focus-ring-box-shadow);
 }

 .editBookmarkPanelBottomButton[default="true"] {
@ -2144,7 +2136,7 @@ html|span.ac-emphasize-text-url {
 }

 #editBMPanel_newFolderButton:-moz-focusring {
-  @hudButtonFocused@
+  box-shadow: var(--focus-ring-box-shadow);
 }

 #editBMPanel_newFolderButton .button-text {
@ -2163,7 +2155,7 @@ html|span.ac-emphasize-text-url {
 }

 #editBMPanel_folderMenuList:-moz-focusring {
-  @hudButtonFocused@
+  box-shadow: var(--focus-ring-box-shadow);
 }

 #editBMPanel_folderMenuList[open="true"],
@ -2203,7 +2195,7 @@ html|span.ac-emphasize-text-url {
 #editBMPanel_folderTree:-moz-focusring,
 #editBMPanel_tagsSelector:-moz-focusring {
  border-color: -moz-mac-focusring;
-  box-shadow: @focusRingShadow@;
+  box-shadow: var(--focus-ring-box-shadow);
 }

 #editBMPanel_folderTree {
@ -2229,7 +2221,7 @@ html|span.ac-emphasize-text-url {

 #editBookmarkPanel .expander-up:-moz-focusring,
 #editBookmarkPanel .expander-down:-moz-focusring {
-  @hudButtonFocused@
+  box-shadow: var(--focus-ring-box-shadow);
 }

 #editBookmarkPanel .expander-up:hover:active,
@ -2533,7 +2525,7 @@ toolbarbutton.chevron > .toolbarbutton-menu-dropmarker {
 .tabbrowser-tab:focus > .tab-stack > .tab-content > .tab-label-container:not([pinned]),
 .tabbrowser-tab:focus > .tab-stack > .tab-content > .tab-icon-image[pinned],
 .tabbrowser-tab:focus > .tab-stack > .tab-content > .tab-throbber[pinned] {
-  box-shadow: @focusRingShadow@;
+  box-shadow: var(--focus-ring-box-shadow);
 }

 #TabsToolbar {
--- a/browser/themes/osx/controlcenter/panel.css
+++ b/browser/themes/osx/controlcenter/panel.css
@ -14,11 +14,11 @@
 }

 .identity-popup-expander:-moz-focusring > .button-box {
-  @hudButtonFocused@
+  box-shadow: var(--focus-ring-box-shadow);
 }

 .identity-popup-permission-remove-button:-moz-focusring {
-  box-shadow: @focusRingShadow@;
+  box-shadow: var(--focus-ring-box-shadow);
 }

 #identity-popup-multiView > .panel-viewcontainer > .panel-viewstack > .panel-subviews {
@ -49,6 +49,7 @@
 #tracking-action-unblock:-moz-focusring,
 #tracking-action-unblock-private:-moz-focusring,
 #identity-popup-securityView-body > button:-moz-focusring {
-  @hudButtonFocused@
+  box-shadow: var(--focus-ring-box-shadow);
 }

+
--- a/browser/themes/osx/shared.inc
+++ b/browser/themes/osx/shared.inc
@ -10,4 +10,3 @@
 %define fgTabBackgroundColor transparent
 %define hudButton -moz-appearance: none; color: #434343; border-radius: 4px; border: 1px solid #b5b5b5; background: linear-gradient(#fff, #f2f2f2); box-shadow: inset 0 1px rgba(255,255,255,.8), inset 0 0 1px rgba(255,255, 255,.25), 0 1px rgba(255,255,255,.3); background-clip: padding-box; background-origin: padding-box; padding: 2px 6px;
 %define hudButtonPressed box-shadow: inset 0 1px 4px -3px #000, 0 1px rgba(255,255,255,.3);
-%define hudButtonFocused box-shadow: 0 0 1px -moz-mac-focusring inset, 0 0 4px 1px -moz-mac-focusring, 0 0 2px 1px -moz-mac-focusring;
--- a/devtools/client/commandline/test/browser_cmd_highlight_01.js
+++ b/devtools/client/commandline/test/browser_cmd_highlight_01.js
@ -85,6 +85,12 @@ function* spawnTest() {
    }
  ]);

+  // Hide all highlighters before finishing the test.
+  yield helpers.audit(options, [{
+    setup: "unhighlight",
+    exec: {}
+  }]);
+
  yield helpers.closeToolbar(options);
  yield helpers.closeTab(options);
 }
--- a/devtools/client/inspector/grids/grid-inspector.js
+++ b/devtools/client/inspector/grids/grid-inspector.js
@ -47,6 +47,7 @@ function GridInspector(inspector, window) {

  this.onGridLayoutChange = this.onGridLayoutChange.bind(this);
  this.onHighlighterChange = this.onHighlighterChange.bind(this);
+  this.onMarkupMutation = this.onMarkupMutation.bind(this);
  this.onSetGridOverlayColor = this.onSetGridOverlayColor.bind(this);
  this.onShowBoxModelHighlighterForNode =
    this.onShowBoxModelHighlighterForNode.bind(this);
@ -86,6 +87,7 @@ GridInspector.prototype = {

    this.highlighters.on("grid-highlighter-hidden", this.onHighlighterChange);
    this.highlighters.on("grid-highlighter-shown", this.onHighlighterChange);
+    this.inspector.on("markupmutation", this.onMarkupMutation);
    this.inspector.sidebar.on("select", this.onSidebarSelect);

    this.onSidebarSelect();
@ -98,6 +100,7 @@ GridInspector.prototype = {
  destroy() {
    this.highlighters.off("grid-highlighter-hidden", this.onHighlighterChange);
    this.highlighters.off("grid-highlighter-shown", this.onHighlighterChange);
+    this.inspector.off("markupmutation", this.onMarkupMutation);
    this.inspector.sidebar.off("select", this.onSidebarSelect);
    this.layoutInspector.off("grid-layout-changed", this.onGridLayoutChange);

@ -298,6 +301,14 @@ GridInspector.prototype = {
    this.store.dispatch(updateGridColor(nodeFront, color));
  },

+  /**
+   * Handler for the "markupmutation" event fired by the inspector. On markup mutations,
+   * update the grid panel content.
+   */
+  onMarkupMutation() {
+    this.updateGridPanel();
+  },
+
  /**
   * Handler for a change in the grid overlay color picker for a grid container.
   *
--- a/devtools/client/inspector/inspector.js
+++ b/devtools/client/inspector/inspector.js
@ -86,6 +86,8 @@ const PORTRAIT_MODE_WIDTH = 700;
 *      to source-mapped files)
 */
 function Inspector(toolbox) {
+  EventEmitter.decorate(this);
+
  this._toolbox = toolbox;
  this._target = toolbox.target;
  this.panelDoc = window.document;
@ -114,8 +116,6 @@ function Inspector(toolbox) {

  this._target.on("will-navigate", this._onBeforeNavigate);
  this._detectingActorFeatures = this._detectActorFeatures();
-
-  EventEmitter.decorate(this);
 }

 Inspector.prototype = {
--- a/devtools/client/inspector/rules/test/browser.ini
+++ b/devtools/client/inspector/rules/test/browser.ini
@ -150,6 +150,7 @@ skip-if = os == "mac" # Bug 1245996 : click on scrollbar not working on OSX
 [browser_rules_filtereditor-commit-on-ENTER.js]
 [browser_rules_filtereditor-revert-on-ESC.js]
 skip-if = (os == "win" && debug) # bug 963492: win.
+[browser_rules_grid-highlighter-on-mutation.js]
 [browser_rules_grid-highlighter-on-navigate.js]
 [browser_rules_grid-highlighter-on-reload.js]
 [browser_rules_grid-highlighter-restored-after-reload.js]
--- a/devtools/client/inspector/rules/test/browser_rules_grid-highlighter-on-mutation.js
+++ b/devtools/client/inspector/rules/test/browser_rules_grid-highlighter-on-mutation.js
@ -0,0 +1,44 @@
+/* vim: set ft=javascript ts=2 et sw=2 tw=80: */
+/* Any copyright is dedicated to the Public Domain.
+ http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+// Tests that the grid highlighter is hidden when the highlighted grid container is
+// removed from the page.
+
+const TEST_URI = `
+  <style type='text/css'>
+    #grid {
+      display: grid;
+    }
+  </style>
+  <div id="grid">
+    <div id="cell1">cell1</div>
+    <div id="cell2">cell2</div>
+  </div>
+`;
+
+add_task(function* () {
+  yield addTab("data:text/html;charset=utf-8," + encodeURIComponent(TEST_URI));
+  let {inspector, view, testActor} = yield openRuleView();
+  let highlighters = view.highlighters;
+
+  yield selectNode("#grid", inspector);
+  let container = getRuleViewProperty(view, "#grid", "display").valueSpan;
+  let gridToggle = container.querySelector(".ruleview-grid");
+
+  info("Toggling ON the CSS grid highlighter from the rule-view.");
+  let onHighlighterShown = highlighters.once("grid-highlighter-shown");
+  gridToggle.click();
+  yield onHighlighterShown;
+  ok(highlighters.gridHighlighterShown, "CSS grid highlighter is shown.");
+
+  let onHighlighterHidden = highlighters.once("grid-highlighter-hidden");
+  info("Remove the #grid container in the content page");
+  testActor.eval(`
+    content.document.querySelector("#grid").remove();
+  `);
+  yield onHighlighterHidden;
+  ok(!highlighters.gridHighlighterShown, "CSS grid highlighter is hidden.");
+});
--- a/devtools/client/inspector/shared/highlighters-overlay.js
+++ b/devtools/client/inspector/shared/highlighters-overlay.js
@ -42,13 +42,15 @@ function HighlightersOverlay(inspector) {
  };

  this.onClick = this.onClick.bind(this);
+  this.onMarkupMutation = this.onMarkupMutation.bind(this);
  this.onMouseMove = this.onMouseMove.bind(this);
  this.onMouseOut = this.onMouseOut.bind(this);
  this.onWillNavigate = this.onWillNavigate.bind(this);
  this.onNavigate = this.onNavigate.bind(this);
  this._handleRejection = this._handleRejection.bind(this);

-  // Add target events, not specific to a given view.
+  // Add inspector events, not specific to a given view.
+  this.inspector.on("markupmutation", this.onMarkupMutation);
  this.inspector.target.on("navigate", this.onNavigate);
  this.inspector.target.on("will-navigate", this.onWillNavigate);

@ -428,6 +430,30 @@ HighlightersOverlay.prototype = {
    this._hideHoveredHighlighter();
  },

+  /**
+   * Handler function for "markupmutation" events. Hides the grid highlighter if the grid
+   * container is no longer in the DOM tree.
+   */
+  onMarkupMutation: Task.async(function* (evt, mutations) {
+    let hasInterestingMutation = mutations.some(mut => mut.type === "childList");
+    if (!hasInterestingMutation || !this.gridHighlighterShown) {
+      // Bail out if the mutations did not remove nodes, or if no grid highlighter is
+      // displayed.
+      return;
+    }
+
+    let nodeFront = this.gridHighlighterShown;
+
+    try {
+      let isInTree = yield this.inspector.walker.isInDOMTree(nodeFront);
+      if (!isInTree) {
+        this.hideGridHighlighter(nodeFront);
+      }
+    } catch (e) {
+      console.error(e);
+    }
+  }),
+
  /**
   * Restore saved highlighter state after navigate.
   */
@ -464,7 +490,8 @@ HighlightersOverlay.prototype = {
      }
    }

-    // Remove target events.
+    // Remove inspector events.
+    this.inspector.off("markupmutation", this.onMarkupMutation);
    this.inspector.target.off("navigate", this.onNavigate);
    this.inspector.target.off("will-navigate", this.onWillNavigate);

--- a/devtools/server/actors/highlighters/auto-refresh.js
+++ b/devtools/server/actors/highlighters/auto-refresh.js
@ -119,7 +119,7 @@ AutoRefreshHighlighter.prototype = {
   * Hide the highlighter
   */
  hide: function () {
-    if (!this._isNodeValid(this.currentNode)) {
+    if (Cu.isDeadWrapper(this.highlighterEnv.window)) {
      return;
    }

--- a/devtools/server/actors/highlighters/css-grid.js
+++ b/devtools/server/actors/highlighters/css-grid.js
@ -52,11 +52,7 @@ const GRID_GAP_ALPHA = 0.5;
 /**
 * Cached used by `CssGridHighlighter.getGridGapPattern`.
 */
-const gCachedGridPattern = new WeakMap();
-// WeakMap key for the Row grid pattern.
-const ROW_KEY = {};
-// WeakMap key for the Column grid pattern.
-const COLUMN_KEY = {};
+const gCachedGridPattern = new Map();

 // That's the maximum size we can allocate for the canvas, in bytes. See:
 // http://searchfox.org/mozilla-central/source/gfx/thebes/gfxPrefs.h#401
@ -362,22 +358,33 @@ CssGridHighlighter.prototype = extend(AutoRefreshHighlighter.prototype, {
  },

  /**
-   * Gets the grid gap pattern used to render the gap regions.
+   * Gets the grid gap pattern used to render the gap regions based on the device
+   * pixel ratio given.
   *
+   * @param {Number} devicePixelRatio
+   *         The device pixel ratio we want the pattern for.
   * @param  {Object} dimension
-   *         Refers to the WeakMap key for the grid dimension type which is either the
-   *         constant COLUMN or ROW.
+   *         Refers to the Map key for the grid dimension type which is either the
+   *         constant COLUMNS or ROWS.
   * @return {CanvasPattern} grid gap pattern.
   */
-  getGridGapPattern(dimension) {
-    if (gCachedGridPattern.has(dimension)) {
-      return gCachedGridPattern.get(dimension);
+  getGridGapPattern(devicePixelRatio, dimension) {
+    let gridPatternMap = null;
+
+    if (gCachedGridPattern.has(devicePixelRatio)) {
+      gridPatternMap = gCachedGridPattern.get(devicePixelRatio);
+    } else {
+      gridPatternMap = new Map();
+    }
+
+    if (gridPatternMap.has(dimension)) {
+      return gridPatternMap.get(dimension);
    }

    // Create the diagonal lines pattern for the rendering the grid gaps.
    let canvas = createNode(this.win, { nodeType: "canvas" });
-    canvas.width = GRID_GAP_PATTERN_WIDTH;
-    canvas.height = GRID_GAP_PATTERN_HEIGHT;
+    let width = canvas.width = GRID_GAP_PATTERN_WIDTH * devicePixelRatio;
+    let height = canvas.height = GRID_GAP_PATTERN_HEIGHT * devicePixelRatio;

    let ctx = canvas.getContext("2d");
    ctx.save();
@ -385,12 +392,12 @@ CssGridHighlighter.prototype = extend(AutoRefreshHighlighter.prototype, {
    ctx.beginPath();
    ctx.translate(.5, .5);

-    if (dimension === COLUMN_KEY) {
+    if (dimension === COLUMNS) {
      ctx.moveTo(0, 0);
-      ctx.lineTo(GRID_GAP_PATTERN_WIDTH, GRID_GAP_PATTERN_HEIGHT);
+      ctx.lineTo(width, height);
    } else {
-      ctx.moveTo(GRID_GAP_PATTERN_WIDTH, 0);
-      ctx.lineTo(0, GRID_GAP_PATTERN_HEIGHT);
+      ctx.moveTo(width, 0);
+      ctx.lineTo(0, height);
    }

    ctx.strokeStyle = this.color;
@ -399,7 +406,10 @@ CssGridHighlighter.prototype = extend(AutoRefreshHighlighter.prototype, {
    ctx.restore();

    let pattern = ctx.createPattern(canvas, "repeat");
-    gCachedGridPattern.set(dimension, pattern);
+
+    gridPatternMap.set(dimension, pattern);
+    gCachedGridPattern.set(devicePixelRatio, gridPatternMap);
+
    return pattern;
  },

@ -433,8 +443,7 @@ CssGridHighlighter.prototype = extend(AutoRefreshHighlighter.prototype, {
  },

  _clearCache() {
-    gCachedGridPattern.delete(ROW_KEY);
-    gCachedGridPattern.delete(COLUMN_KEY);
+    gCachedGridPattern.clear();
  },

  /**
@ -555,7 +564,7 @@ CssGridHighlighter.prototype = extend(AutoRefreshHighlighter.prototype, {
    root.setAttribute("style",
      `position:absolute; width:${width}px;height:${height}px; overflow:hidden`);

-    setIgnoreLayoutChanges(false, this.highlighterEnv.window.document.documentElement);
+    setIgnoreLayoutChanges(false, this.highlighterEnv.document.documentElement);
    return true;
  },

@ -695,7 +704,6 @@ CssGridHighlighter.prototype = extend(AutoRefreshHighlighter.prototype, {
    this.canvas.setAttribute("height", height);
    this.canvas.setAttribute("style",
      `width:${width / ratio}px;height:${height / ratio}px;`);
-    this.ctx.scale(ratio, ratio);

    this.ctx.clearRect(0, 0, width, height);
  },
@ -821,6 +829,12 @@ CssGridHighlighter.prototype = extend(AutoRefreshHighlighter.prototype, {
   *         The grid line type - "edge", "explicit", or "implicit".
   */
  renderLine(linePos, startPos, endPos, dimensionType, lineType) {
+    let ratio = this.win.devicePixelRatio;
+
+    linePos = Math.round(linePos * ratio);
+    startPos = Math.round(startPos * ratio);
+    endPos = Math.round(endPos * ratio);
+
    this.ctx.save();
    this.ctx.setLineDash(GRID_LINES_PROPERTIES[lineType].lineDash);
    this.ctx.beginPath();
@ -855,6 +869,11 @@ CssGridHighlighter.prototype = extend(AutoRefreshHighlighter.prototype, {
   *         The grid dimension type which is either the constant COLUMNS or ROWS.
   */
  renderGridLineNumber(lineNumber, linePos, startPos, dimensionType) {
+    let ratio = this.win.devicePixelRatio;
+
+    linePos = Math.round(linePos * ratio);
+    startPos = Math.round(startPos * ratio);
+
    this.ctx.save();

    let textWidth = this.ctx.measureText(lineNumber).width;
@ -888,16 +907,21 @@ CssGridHighlighter.prototype = extend(AutoRefreshHighlighter.prototype, {
   *         The grid dimension type which is either the constant COLUMNS or ROWS.
   */
  renderGridGap(linePos, startPos, endPos, breadth, dimensionType) {
+    let ratio = this.win.devicePixelRatio;
+
+    linePos = Math.round(linePos * ratio);
+    startPos = Math.round(startPos * ratio);
+    endPos = Math.round(endPos * ratio);
+    breadth = Math.round(breadth * ratio);
+
    this.ctx.save();
+    this.ctx.fillStyle = this.getGridGapPattern(ratio, dimensionType);

    if (dimensionType === COLUMNS) {
-      this.ctx.fillStyle = this.getGridGapPattern(COLUMN_KEY);
      this.ctx.fillRect(linePos, startPos, breadth, endPos - startPos);
    } else {
-      this.ctx.fillStyle = this.getGridGapPattern(ROW_KEY);
      this.ctx.fillRect(startPos, linePos, endPos - startPos, breadth);
    }
-
    this.ctx.restore();
  },

@ -1004,7 +1028,7 @@ CssGridHighlighter.prototype = extend(AutoRefreshHighlighter.prototype, {
    this._hideGridElements();
    this._hideGridAreaInfoBar();
    this._hideGridCellInfoBar();
-    setIgnoreLayoutChanges(false, this.highlighterEnv.window.document.documentElement);
+    setIgnoreLayoutChanges(false, this.highlighterEnv.document.documentElement);
  },

  _hideGrid() {
--- a/devtools/server/actors/highlighters/geometry-editor.js
+++ b/devtools/server/actors/highlighters/geometry-editor.js
@ -516,7 +516,7 @@ GeometryEditorHighlighter.prototype = extend(AutoRefreshHighlighter.prototype, {
    let node = this.currentNode;
    this.markup.scaleRootElement(node, this.ID_CLASS_PREFIX + "root");

-    setIgnoreLayoutChanges(false, node.ownerDocument.documentElement);
+    setIgnoreLayoutChanges(false, this.highlighterEnv.document.documentElement);
    return true;
  },

@ -596,8 +596,7 @@ GeometryEditorHighlighter.prototype = extend(AutoRefreshHighlighter.prototype, {

    this.definedProperties.clear();

-    setIgnoreLayoutChanges(false,
-      this.currentNode.ownerDocument.documentElement);
+    setIgnoreLayoutChanges(false, this.highlighterEnv.document.documentElement);
  },

  hideArrows: function () {
--- a/devtools/server/actors/highlighters/utils/markup.js
+++ b/devtools/server/actors/highlighters/utils/markup.js
@ -253,13 +253,7 @@ function CanvasFrameAnonymousContentHelper(highlighterEnv, nodeBuilder) {

 CanvasFrameAnonymousContentHelper.prototype = {
  destroy: function () {
-    try {
-      let doc = this.anonymousContentDocument;
-      doc.removeAnonymousContent(this._content);
-    } catch (e) {
-      // If the current window isn't the one the content was inserted into, this
-      // will fail, but that's fine.
-    }
+    this._remove();
    this.highlighterEnv.off("window-ready", this._onWindowReady);
    this.highlighterEnv = this.nodeBuilder = this._content = null;
    this.anonymousContentDocument = null;
@ -306,8 +300,26 @@ CanvasFrameAnonymousContentHelper.prototype = {
    this._content = doc.insertAnonymousContent(node);
  },

+  _remove() {
+    try {
+      let doc = this.anonymousContentDocument;
+      doc.removeAnonymousContent(this._content);
+    } catch (e) {
+      // If the current window isn't the one the content was inserted into, this
+      // will fail, but that's fine.
+    }
+  },
+
+  /**
+   * The "window-ready" event can be triggered when:
+   *   - a new window is created
+   *   - a window is unfrozen from bfcache
+   *   - when first attaching to a page
+   *   - when swapping frame loaders (moving tabs, toggling RDM)
+   */
  _onWindowReady: function (e, {isTopLevel}) {
    if (isTopLevel) {
+      this._remove();
      this._removeAllListeners();
      this._insert();
      this.anonymousContentDocument = this.highlighterEnv.document;
--- a/devtools/server/actors/tab.js
+++ b/devtools/server/actors/tab.js
@ -152,7 +152,7 @@ function getInnerId(window) {
 *  - navigate
 *    This event is fired once the document's readyState is "complete".
 *  - window-ready
- *    This event is fired on three distinct scenarios:
+ *    This event is fired in various distinct scenarios:
 *     * When a new Window object is crafted, equivalent of `DOMWindowCreated`.
 *       It is dispatched before any page script is executed.
 *     * We will have already received a window-ready event for this window
@ -161,6 +161,8 @@ function getInnerId(window) {
 *       this page, so it's now live again and we should resume handling it.
 *     * For each existing document, when an `attach` request is received.
 *       At this point scripts in the page will be already loaded.
+ *     * When `swapFrameLoaders` is used, such as with moving tabs between
+ *       windows or toggling Responsive Design Mode.
 *  - window-destroyed
 *    This event is fired in two cases:
 *     * When the window object is destroyed, i.e. when the related document
--- a/dom/animation/KeyframeUtils.cpp
+++ b/dom/animation/KeyframeUtils.cpp
@ -598,22 +598,13 @@ KeyframeUtils::GetComputedKeyframeValues(
  const ServoComputedStyleValues& aServoValues)
 {
  MOZ_ASSERT(aElement);
-  MOZ_ASSERT(aElement->OwnerDoc()->IsStyledByServo());
+  MOZ_ASSERT(aElement->IsStyledByServo());

  nsPresContext* presContext = nsContentUtils::GetContextForContent(aElement);
  MOZ_ASSERT(presContext);

-  nsTArray<ComputedKeyframeValues> result(aKeyframes.Length());
-
-  // Construct each nsTArray<PropertyStyleAnimationValuePair> here.
-  result.AppendElements(aKeyframes.Length());
-
-  Servo_GetComputedKeyframeValues(&aKeyframes,
-                                  aServoValues.mCurrentStyle,
-                                  aServoValues.mParentStyle,
-                                  presContext,
-                                  &result);
-  return result;
+  return presContext->StyleSet()->AsServo()
+    ->GetComputedKeyframeValuesFor(aKeyframes, aElement, aServoValues);
 }

 /* static */ nsTArray<ComputedKeyframeValues>
--- a/dom/base/moz.build
+++ b/dom/base/moz.build
@ -186,7 +186,6 @@ EXPORTS.mozilla.dom += [
    'ImageEncoder.h',
    'ImageTracker.h',
    'ImportManager.h',
-    'IntlUtils.h',
    'Link.h',
    'Location.h',
    'NameSpaceConstants.h',
@ -260,7 +259,6 @@ UNIFIED_SOURCES += [
    'ImageEncoder.cpp',
    'ImageTracker.cpp',
    'ImportManager.cpp',
-    'IntlUtils.cpp',
    'Link.cpp',
    'Location.cpp',
    'Navigator.cpp',
@ -375,6 +373,14 @@ if CONFIG['FUZZING']:
        'FuzzingFunctions.cpp',
    ]

+if CONFIG['ENABLE_INTL_API']:
+    UNIFIED_SOURCES += [
+        'IntlUtils.cpp',
+    ]
+    EXPORTS.mozilla.dom += [
+        'IntlUtils.h',
+    ]
+
 # these files couldn't be in UNIFIED_SOURCES for now for reasons given below:
 SOURCES += [
    # Several conflicts with other bindings.
--- a/dom/base/nsAttrValue.cpp
+++ b/dom/base/nsAttrValue.cpp
@ -1725,7 +1725,8 @@ nsAttrValue::ParseStyleAttribute(const nsAString& aString,

  RefPtr<DeclarationBlock> decl;
  if (ownerDoc->GetStyleBackendType() == StyleBackendType::Servo) {
-    decl = ServoDeclarationBlock::FromCssText(aString);
+    GeckoParserExtraData data(baseURI, docURI, aElement->NodePrincipal());
+    decl = ServoDeclarationBlock::FromCssText(aString, data);
  } else {
    css::Loader* cssLoader = ownerDoc->CSSLoader();
    nsCSSParser cssParser(cssLoader);
--- a/dom/base/nsGkAtomList.h
+++ b/dom/base/nsGkAtomList.h
@ -2214,6 +2214,7 @@ GK_ATOM(sans_serif, "sans-serif")
 GK_ATOM(cursive, "cursive")
 GK_ATOM(fantasy, "fantasy")
 GK_ATOM(monospace, "monospace")
+GK_ATOM(mozfixed, "-moz-fixed")

 // IPC stuff
 GK_ATOM(Remote, "remote")
--- a/dom/base/nsGlobalWindow.cpp
+++ b/dom/base/nsGlobalWindow.cpp
@ -227,7 +227,9 @@
 #include "mozilla/dom/Fetch.h"
 #include "mozilla/dom/FunctionBinding.h"
 #include "mozilla/dom/HashChangeEvent.h"
+#ifdef ENABLE_INTL_API
 #include "mozilla/dom/IntlUtils.h"
+#endif
 #include "mozilla/dom/MozSelfSupportBinding.h"
 #include "mozilla/dom/PopStateEvent.h"
 #include "mozilla/dom/PopupBlockedEvent.h"
@ -1921,7 +1923,9 @@ nsGlobalWindow::CleanUp()

  mServiceWorkerRegistrationTable.Clear();

+#ifdef ENABLE_INTL_API
  mIntlUtils = nullptr;
+#endif
 }

 void
@ -2212,7 +2216,9 @@ NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN_INTERNAL(nsGlobalWindow)
  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mPaintWorklet)
  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mExternal)
  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mMozSelfSupport)
+#ifdef ENABLE_INTL_API
  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mIntlUtils)
+#endif

  tmp->TraverseHostObjectURIs(cb);
 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
@ -2287,7 +2293,9 @@ NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(nsGlobalWindow)
  NS_IMPL_CYCLE_COLLECTION_UNLINK(mPaintWorklet)
  NS_IMPL_CYCLE_COLLECTION_UNLINK(mExternal)
  NS_IMPL_CYCLE_COLLECTION_UNLINK(mMozSelfSupport)
+#ifdef ENABLE_INTL_API
  NS_IMPL_CYCLE_COLLECTION_UNLINK(mIntlUtils)
+#endif

  tmp->UnlinkHostObjectURIs();

@ -14931,6 +14939,7 @@ nsGlobalWindow::GetAppLocales(nsTArray<nsString>& aLocales)
  }
 }

+#ifdef ENABLE_INTL_API
 IntlUtils*
 nsGlobalWindow::GetIntlUtils(ErrorResult& aError)
 {
@ -14942,7 +14951,7 @@ nsGlobalWindow::GetIntlUtils(ErrorResult& aError)

  return mIntlUtils;
 }
-
+#endif

 template class nsPIDOMWindow<mozIDOMWindowProxy>;
 template class nsPIDOMWindow<mozIDOMWindow>;
--- a/dom/base/nsGlobalWindow.h
+++ b/dom/base/nsGlobalWindow.h
@ -122,7 +122,9 @@ enum class ImageBitmapFormat : uint8_t;
 class IdleRequest;
 class IdleRequestCallback;
 class IncrementalRunnable;
+#ifdef ENABLE_INTL_API
 class IntlUtils;
+#endif
 class Location;
 class MediaQueryList;
 class MozSelfSupport;
@ -951,8 +953,10 @@ public:
  void
  GetAppLocales(nsTArray<nsString>& aLocales);

+#ifdef ENABLE_INTL_API
  mozilla::dom::IntlUtils*
  GetIntlUtils(mozilla::ErrorResult& aRv);
+#endif

 protected:
  bool AlertOrConfirm(bool aAlert, const nsAString& aMessage,
@ -2036,7 +2040,9 @@ protected:

  RefPtr<mozilla::dom::VREventObserver> mVREventObserver;

+#ifdef ENABLE_INTL_API
  RefPtr<mozilla::dom::IntlUtils> mIntlUtils;
+#endif

  friend class nsDOMScriptableHelper;
  friend class nsDOMWindowUtils;
--- a/dom/bindings/Bindings.conf
+++ b/dom/bindings/Bindings.conf
@ -236,11 +236,6 @@ DOMInterfaces = {
    'wrapperCache': False
 },

-'CSSMediaRule': {
-    'nativeType': 'mozilla::css::MediaRule',
-    'headerFile': 'nsCSSRules.h',
-},
-
 'CSSMozDocumentRule': {
    'nativeType': 'mozilla::css::DocumentRule',
    'headerFile': 'nsCSSRules.h',
@ -615,10 +610,6 @@ DOMInterfaces = {
    'nativeType': 'mozilla::DOMLocalMediaStream'
 },

-'MediaList': {
-    'nativeType': 'nsMediaList',
-},
-
 'MediaKeys' : {
    'implicitJSContext': [ 'createSession']
 },
--- a/dom/ipc/ProcessHangMonitor.cpp
+++ b/dom/ipc/ProcessHangMonitor.cpp
@ -246,6 +246,12 @@ public:
 private:
  bool TakeBrowserMinidump(const PluginHangData& aPhd, nsString& aCrashId);

+  void SendHangNotification(const HangData& aHangData,
+                            const nsString& aBrowserDumpId,
+                            bool aTakeMinidump);
+
+  void ClearHangNotification();
+
  void DispatchTabChildNotReady(TabId aTabId);

  void ForcePaintOnThread(TabId aTabId, uint64_t aLayerObserverEpoch);
@ -701,55 +707,45 @@ HangMonitorParent::Bind(Endpoint<PProcessHangMonitorParent>&& aEndpoint)
  MOZ_ASSERT(ok);
 }

-class HangObserverNotifier final : public Runnable
+void
+HangMonitorParent::SendHangNotification(const HangData& aHangData,
+                                        const nsString& aBrowserDumpId,
+                                        bool aTakeMinidump)
 {
-public:
-  HangObserverNotifier(HangMonitoredProcess* aProcess,
-                       HangMonitorParent *aParent,
-                       const HangData& aHangData,
-                       const nsString& aBrowserDumpId,
-                       bool aTakeMinidump)
-    : mProcess(aProcess),
-      mParent(aParent),
-      mHangData(aHangData),
-      mBrowserDumpId(aBrowserDumpId),
-      mTakeMinidump(aTakeMinidump)
-  {}
+  // chrome process, main thread
+  MOZ_RELEASE_ASSERT(NS_IsMainThread());

-  NS_IMETHOD
-  Run() override
-  {
-    // chrome process, main thread
-    MOZ_RELEASE_ASSERT(NS_IsMainThread());
-
-    nsString dumpId;
-    if ((mHangData.type() == HangData::TPluginHangData) && mTakeMinidump) {
-      // We've been handed a partial minidump; complete it with plugin and
-      // content process dumps.
-      const PluginHangData& phd = mHangData.get_PluginHangData();
-      plugins::TakeFullMinidump(phd.pluginId(), phd.contentProcessId(),
-                                mBrowserDumpId, dumpId);
-      mParent->UpdateMinidump(phd.pluginId(), dumpId);
-    } else {
-      // We already have a full minidump; go ahead and use it.
-      dumpId = mBrowserDumpId;
-    }
-
-    mProcess->SetHangData(mHangData, dumpId);
-
-    nsCOMPtr<nsIObserverService> observerService =
-      mozilla::services::GetObserverService();
-    observerService->NotifyObservers(mProcess, "process-hang-report", nullptr);
-    return NS_OK;
+  nsString dumpId;
+  if ((aHangData.type() == HangData::TPluginHangData) && aTakeMinidump) {
+    // We've been handed a partial minidump; complete it with plugin and
+    // content process dumps.
+    const PluginHangData& phd = aHangData.get_PluginHangData();
+    plugins::TakeFullMinidump(phd.pluginId(), phd.contentProcessId(),
+                              aBrowserDumpId, dumpId);
+    UpdateMinidump(phd.pluginId(), dumpId);
+  } else {
+    // We already have a full minidump; go ahead and use it.
+    dumpId = aBrowserDumpId;
  }

-private:
-  RefPtr<HangMonitoredProcess> mProcess;
-  HangMonitorParent* mParent;
-  HangData mHangData;
-  nsAutoString mBrowserDumpId;
-  bool mTakeMinidump;
-};
+  mProcess->SetHangData(aHangData, dumpId);
+
+  nsCOMPtr<nsIObserverService> observerService =
+    mozilla::services::GetObserverService();
+  observerService->NotifyObservers(mProcess, "process-hang-report", nullptr);
+}
+
+void
+HangMonitorParent::ClearHangNotification()
+{
+  // chrome process, main thread
+  MOZ_RELEASE_ASSERT(NS_IsMainThread());
+  mProcess->ClearHang();
+
+  nsCOMPtr<nsIObserverService> observerService =
+    mozilla::services::GetObserverService();
+  observerService->NotifyObservers(mProcess, "clear-hang-report", nullptr);
+}

 // Take a minidump of the browser process if one wasn't already taken for the
 // plugin that caused the hang. Return false if a dump was already available or
@ -817,37 +813,14 @@ HangMonitorParent::RecvHangEvidence(const HangData& aHangData)

  MonitorAutoLock lock(mMonitor);

-  nsCOMPtr<nsIRunnable> notifier =
-    new HangObserverNotifier(mProcess, this, aHangData, crashId, takeMinidump);
-  NS_DispatchToMainThread(notifier);
+  NS_DispatchToMainThread(
+    mMainThreadTaskFactory.NewRunnableMethod(
+      &HangMonitorParent::SendHangNotification, aHangData, crashId,
+      takeMinidump));

  return IPC_OK();
 }

-class ClearHangNotifier final : public Runnable
-{
-public:
-  explicit ClearHangNotifier(HangMonitoredProcess* aProcess)
-    : mProcess(aProcess)
-  {}
-
-  NS_IMETHOD
-  Run() override
-  {
-    // chrome process, main thread
-    MOZ_RELEASE_ASSERT(NS_IsMainThread());
-    mProcess->ClearHang();
-
-    nsCOMPtr<nsIObserverService> observerService =
-      mozilla::services::GetObserverService();
-    observerService->NotifyObservers(mProcess, "clear-hang-report", nullptr);
-    return NS_OK;
-  }
-
-private:
-  RefPtr<HangMonitoredProcess> mProcess;
-};
-
 mozilla::ipc::IPCResult
 HangMonitorParent::RecvClearHang()
 {
@ -862,9 +835,9 @@ HangMonitorParent::RecvClearHang()

  MonitorAutoLock lock(mMonitor);

-  nsCOMPtr<nsIRunnable> notifier =
-    new ClearHangNotifier(mProcess);
-  NS_DispatchToMainThread(notifier);
+  NS_DispatchToMainThread(
+    mMainThreadTaskFactory.NewRunnableMethod(
+      &HangMonitorParent::ClearHangNotification));

  return IPC_OK();
 }
--- a/dom/media/MediaMIMETypes.h
+++ b/dom/media/MediaMIMETypes.h
@ -7,9 +7,9 @@
 #ifndef MediaMIMETypes_h_
 #define MediaMIMETypes_h_

+#include "VideoUtils.h"
 #include "mozilla/Maybe.h"
 #include "nsString.h"
-#include "VideoUtils.h"

 namespace mozilla {

@ -52,7 +52,8 @@ public:
  // Implicit so MEDIAMIMETYPE can be used wherever a MediaMIMEType is expected.
  MOZ_IMPLICIT MediaMIMEType(const DependentMediaMIMEType& aType)
    : mMIMEType(aType.AsDependentString())
-  {}
+  {
+  }

  // MIME "type/subtype", always lowercase.
  const nsACString& AsString() const { return mMIMEType; }
@ -106,16 +107,15 @@ Maybe<MediaMIMEType> MakeMediaMIMEType(const char* aType);
 class MediaCodecs
 {
 public:
-  MediaCodecs() {}
+  MediaCodecs() { }
  // Construction from a comma-separated list of codecs. Unchecked.
-  explicit MediaCodecs(const nsAString& aCodecs)
-    : mCodecs(aCodecs)
-  {}
+  explicit MediaCodecs(const nsAString& aCodecs) : mCodecs(aCodecs) { }
  // Construction from a literal comma-separated list of codecs. Unchecked.
  template <size_t N>
  explicit MediaCodecs(const char (&aCodecs)[N])
    : mCodecs(NS_ConvertUTF8toUTF16(aCodecs, N - 1))
-  {}
+  {
+  }

  bool IsEmpty() const { return mCodecs.IsEmpty(); }
  const nsAString& AsString() const { return mCodecs; }
--- a/dom/media/mediasource/MediaSourceDemuxer.cpp
+++ b/dom/media/mediasource/MediaSourceDemuxer.cpp
@ -4,16 +4,17 @@
 * 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 "MediaSourceDemuxer.h"
+
+#include "MediaSourceUtils.h"
+#include "OpusDecoder.h"
+#include "SourceBufferList.h"
+#include "nsPrintfCString.h"
+
 #include <algorithm>
 #include <limits>
 #include <stdint.h>

-#include "MediaSourceDemuxer.h"
-#include "MediaSourceUtils.h"
-#include "SourceBufferList.h"
-#include "nsPrintfCString.h"
-#include "OpusDecoder.h"
-
 namespace mozilla {

 typedef TrackInfo::TrackType TrackType;
@ -30,7 +31,8 @@ MediaSourceDemuxer::MediaSourceDemuxer(AbstractThread* aAbstractMainThread)

 // Due to inaccuracies in determining buffer end
 // frames (Bug 1065207). This value is based on videos seen in the wild.
-const TimeUnit MediaSourceDemuxer::EOS_FUZZ = media::TimeUnit::FromMicroseconds(500000);
+const TimeUnit MediaSourceDemuxer::EOS_FUZZ =
+  media::TimeUnit::FromMicroseconds(500000);

 RefPtr<MediaSourceDemuxer::InitPromise>
 MediaSourceDemuxer::Init()
@ -49,7 +51,8 @@ MediaSourceDemuxer::Init()
 }

 void
-MediaSourceDemuxer::AddSizeOfResources(MediaSourceDecoder::ResourceSizes* aSizes)
+MediaSourceDemuxer::AddSizeOfResources(
+  MediaSourceDecoder::ResourceSizes* aSizes)
 {
  MOZ_ASSERT(NS_IsMainThread());

@ -252,36 +255,40 @@ MediaSourceDemuxer::GetMozDebugReaderData(nsACString& aString)
  nsAutoCString result;
  result += nsPrintfCString("Dumping Data for Demuxer: %p\n", this);
  if (mAudioTrack) {
-    result += nsPrintfCString("\tDumping Audio Track Buffer(%s): mLastAudioTime=%f\n"
-                              "\t\tAudio Track Buffer Details: NumSamples=%"
-                              PRIuSIZE " Size=%u Evictable=%u "
-                              "NextGetSampleIndex=%u NextInsertionIndex=%d\n",
-                              mAudioTrack->mAudioTracks.mInfo->mMimeType.get(),
-                              mAudioTrack->mAudioTracks.mNextSampleTime.ToSeconds(),
-                              mAudioTrack->mAudioTracks.mBuffers[0].Length(),
-                              mAudioTrack->mAudioTracks.mSizeBuffer,
-                              mAudioTrack->Evictable(TrackInfo::kAudioTrack),
-                              mAudioTrack->mAudioTracks.mNextGetSampleIndex.valueOr(-1),
-                              mAudioTrack->mAudioTracks.mNextInsertionIndex.valueOr(-1));
+    result += nsPrintfCString(
+      "\tDumping Audio Track Buffer(%s): mLastAudioTime=%f\n"
+      "\t\tAudio Track Buffer Details: NumSamples=%" PRIuSIZE
+      " Size=%u Evictable=%u "
+      "NextGetSampleIndex=%u NextInsertionIndex=%d\n",
+      mAudioTrack->mAudioTracks.mInfo->mMimeType.get(),
+      mAudioTrack->mAudioTracks.mNextSampleTime.ToSeconds(),
+      mAudioTrack->mAudioTracks.mBuffers[0].Length(),
+      mAudioTrack->mAudioTracks.mSizeBuffer,
+      mAudioTrack->Evictable(TrackInfo::kAudioTrack),
+      mAudioTrack->mAudioTracks.mNextGetSampleIndex.valueOr(-1),
+      mAudioTrack->mAudioTracks.mNextInsertionIndex.valueOr(-1));

-    result += nsPrintfCString("\t\tAudio Track Buffered: ranges=%s\n",
-                              DumpTimeRanges(mAudioTrack->SafeBuffered(TrackInfo::kAudioTrack)).get());
+    result += nsPrintfCString(
+      "\t\tAudio Track Buffered: ranges=%s\n",
+      DumpTimeRanges(mAudioTrack->SafeBuffered(TrackInfo::kAudioTrack)).get());
  }
  if (mVideoTrack) {
-    result += nsPrintfCString("\tDumping Video Track Buffer(%s): mLastVideoTime=%f\n"
-                              "\t\tVideo Track Buffer Details: NumSamples=%"
-                              PRIuSIZE " Size=%u Evictable=%u "
-                              "NextGetSampleIndex=%u NextInsertionIndex=%d\n",
-                              mVideoTrack->mVideoTracks.mInfo->mMimeType.get(),
-                              mVideoTrack->mVideoTracks.mNextSampleTime.ToSeconds(),
-                              mVideoTrack->mVideoTracks.mBuffers[0].Length(),
-                              mVideoTrack->mVideoTracks.mSizeBuffer,
-                              mVideoTrack->Evictable(TrackInfo::kVideoTrack),
-                              mVideoTrack->mVideoTracks.mNextGetSampleIndex.valueOr(-1),
-                              mVideoTrack->mVideoTracks.mNextInsertionIndex.valueOr(-1));
+    result += nsPrintfCString(
+      "\tDumping Video Track Buffer(%s): mLastVideoTime=%f\n"
+      "\t\tVideo Track Buffer Details: NumSamples=%" PRIuSIZE
+      " Size=%u Evictable=%u "
+      "NextGetSampleIndex=%u NextInsertionIndex=%d\n",
+      mVideoTrack->mVideoTracks.mInfo->mMimeType.get(),
+      mVideoTrack->mVideoTracks.mNextSampleTime.ToSeconds(),
+      mVideoTrack->mVideoTracks.mBuffers[0].Length(),
+      mVideoTrack->mVideoTracks.mSizeBuffer,
+      mVideoTrack->Evictable(TrackInfo::kVideoTrack),
+      mVideoTrack->mVideoTracks.mNextGetSampleIndex.valueOr(-1),
+      mVideoTrack->mVideoTracks.mNextInsertionIndex.valueOr(-1));

-    result += nsPrintfCString("\t\tVideo Track Buffered: ranges=%s\n",
-                              DumpTimeRanges(mVideoTrack->SafeBuffered(TrackInfo::kVideoTrack)).get());
+    result += nsPrintfCString(
+      "\t\tVideo Track Buffered: ranges=%s\n",
+      DumpTimeRanges(mVideoTrack->SafeBuffered(TrackInfo::kVideoTrack)).get());
  }
  aString += result;
 }
@ -295,8 +302,15 @@ MediaSourceTrackDemuxer::MediaSourceTrackDemuxer(MediaSourceDemuxer* aParent,
  , mMonitor("MediaSourceTrackDemuxer")
  , mReset(true)
  , mPreRoll(TimeUnit::FromMicroseconds(
-      OpusDataDecoder::IsOpus(mParent->GetTrackInfo(mType)->mMimeType) ? 80000
-                                                                       : 0))
+      OpusDataDecoder::IsOpus(mParent->GetTrackInfo(mType)->mMimeType)
+      ? 80000
+      : mParent->GetTrackInfo(mType)->mMimeType.EqualsLiteral("audio/mp4a-latm")
+        // AAC encoder delay is by default 2112 audio frames.
+        // See https://developer.apple.com/library/content/documentation/QuickTime/QTFF/QTFFAppenG/QTFFAppenG.html
+        // So we always seek 2112 frames
+        ? (2112 * 1000000ULL
+           / mParent->GetTrackInfo(mType)->GetAsAudioInfo()->mRate)
+        : 0))
 {
 }

@ -335,9 +349,8 @@ MediaSourceTrackDemuxer::Reset()
      self->mManager->Seek(self->mType, TimeUnit(), TimeUnit());
      {
        MonitorAutoLock mon(self->mMonitor);
-        self->mNextRandomAccessPoint =
-          self->mManager->GetNextRandomAccessPoint(self->mType,
-                                                   MediaSourceDemuxer::EOS_FUZZ);
+        self->mNextRandomAccessPoint = self->mManager->GetNextRandomAccessPoint(
+          self->mType, MediaSourceDemuxer::EOS_FUZZ);
      }
    });
  mParent->GetTaskQueue()->Dispatch(task.forget());
@ -352,7 +365,8 @@ MediaSourceTrackDemuxer::GetNextRandomAccessPoint(media::TimeUnit* aTime)
 }

 RefPtr<MediaSourceTrackDemuxer::SkipAccessPointPromise>
-MediaSourceTrackDemuxer::SkipToNextRandomAccessPoint(const media::TimeUnit& aTimeThreshold)
+MediaSourceTrackDemuxer::SkipToNextRandomAccessPoint(
+  const media::TimeUnit& aTimeThreshold)
 {
  return InvokeAsync<media::TimeUnit&&>(
           mParent->GetTaskQueue(), this, __func__,
@ -440,8 +454,8 @@ MediaSourceTrackDemuxer::DoGetSamples(int32_t aNumSamples)
                                             __func__);
    }
    if (!buffered.ContainsWithStrictEnd(TimeUnit::FromMicroseconds(0))) {
-      return SamplesPromise::CreateAndReject(NS_ERROR_DOM_MEDIA_WAITING_FOR_DATA,
-                                             __func__);
+      return SamplesPromise::CreateAndReject(
+        NS_ERROR_DOM_MEDIA_WAITING_FOR_DATA, __func__);
    }
    mReset = false;
  }
@ -474,7 +488,8 @@ MediaSourceTrackDemuxer::DoGetSamples(int32_t aNumSamples)
 }

 RefPtr<MediaSourceTrackDemuxer::SkipAccessPointPromise>
-MediaSourceTrackDemuxer::DoSkipToNextRandomAccessPoint(const media::TimeUnit& aTimeThreadshold)
+MediaSourceTrackDemuxer::DoSkipToNextRandomAccessPoint(
+  const media::TimeUnit& aTimeThreadshold)
 {
  uint32_t parsed = 0;
  // Ensure that the data we are about to skip to is still available.
--- a/dom/media/mediasource/test/mochitest.ini
+++ b/dom/media/mediasource/test/mochitest.ini
@ -113,6 +113,8 @@ skip-if = ((os == "win" && os_version == "5.1") || (toolkit == 'android')) # Not
 skip-if = ((os == "win" && os_version == "5.1") || (toolkit == 'android')) # Not supported on xp and android 2.3
 [test_SeekToEnd_mp4.html]
 skip-if = ((os == "win" && os_version == "5.1") || (toolkit == 'android')) # Not supported on xp and android 2.3
+[test_SeekToLastFrame_mp4.html]
+skip-if = ((os == "win" && os_version == "5.1") || (toolkit == 'android')) # Not supported on xp and android 2.3
 [test_SeekTwice_mp4.html]
 skip-if = ((os == "win" && os_version == "5.1") || (toolkit == 'android')) # Not supported on xp and android 2.3
 [test_Sequence_mp4.html]
--- a/dom/media/mediasource/test/test_SeekToLastFrame_mp4.html
+++ b/dom/media/mediasource/test/test_SeekToLastFrame_mp4.html
@ -0,0 +1,40 @@
+<!DOCTYPE html>
+<html><head>
+<meta http-equiv="content-type" content="text/html; charset=windows-1252">
+  <title>MSE: Can seek to last frame</title>
+  <script type="text/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
+  <script type="text/javascript" src="mediasource.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
+</head>
+<body>
+<pre id="test"><script class="testbody" type="text/javascript">
+
+SimpleTest.waitForExplicitFinish();
+
+runWithMSE(function(ms, el) {
+  el.controls = true;
+  once(ms, 'sourceopen').then(function() {
+    ok(true, "Receive a sourceopen event");
+    var sb = ms.addSourceBuffer("video/mp4");
+    fetchAndLoad(sb, 'bipbop/bipbop_480_624kbps-video', ['init'], '.mp4')
+    .then(fetchAndLoad.bind(null, sb, 'bipbop/bipbop_480_624kbps-video', range(1, 3), '.m4s'))
+    .then(function() {
+      el.play();
+      // let seek to the last audio frame.
+      el.currentTime = 1.532517;
+      return once(el, 'seeked');
+    })
+    .then(function() {
+      ok(true, "seek completed");
+      ms.endOfStream();
+      return once(el, 'ended');
+    }).then(function() {
+      SimpleTest.finish();
+    });
+  });
+});
+
+</script>
+</pre>
+</body>
+</html>
--- a/dom/media/tests/mochitest/mochitest.ini
+++ b/dom/media/tests/mochitest/mochitest.ini
@ -271,6 +271,8 @@ skip-if = (android_version == '18') # android(Bug 1189784, timeouts on 4.3 emula
 skip-if = (android_version == '18') # android(Bug 1189784, timeouts on 4.3 emulator)
 [test_peerConnection_remoteReofferRollback.html]
 skip-if = (android_version == '18') # android(Bug 1189784, timeouts on 4.3 emulator)
+[test_peerConnection_threeUnbundledConnections.html]
+skip-if = (android_version == '18') # android(Bug 1189784, timeouts on 4.3 emulator)
 [test_selftest.html]
 # Bug 1227781: Crash with bogus TURN server.
 [test_peerConnection_bug1227781.html]
--- a/dom/media/tests/mochitest/test_peerConnection_threeUnbundledConnections.html
+++ b/dom/media/tests/mochitest/test_peerConnection_threeUnbundledConnections.html
@ -0,0 +1,125 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+  <script type="application/javascript" src="pc.js"></script>
+</head>
+<body>
+<pre id="test">
+<script type="application/javascript;version=1.8">
+  createHTML({
+    bug: "1342579",
+    title: "Unbundled PC connects to two different PCs",
+    visible: true
+  });
+
+  const fakeFingerPrint = "a=fingerprint:sha-256 11:11:11:11:11:11:11:11:11:11:11:11:11:11:11:11:11:11:11:11:11:11:11:11:11:11:11:11:11:11:11:11";
+
+  var pc1 = new RTCPeerConnection();
+  var pc2 = new RTCPeerConnection();
+  var pc3 = new RTCPeerConnection();
+
+  var add = (pc, can, failed) => can && pc.addIceCandidate(can).catch(failed);
+  pc1.onicecandidate = e => {
+    add(pc2, e.candidate, generateErrorCallback())
+    add(pc3, e.candidate, generateErrorCallback())
+  };
+  pc2.onicecandidate = e => add(pc1, e.candidate, generateErrorCallback());
+  pc3.onicecandidate = e => add(pc1, e.candidate, generateErrorCallback());
+
+  var ice1Finished, ice2Finished, ice3Finished;
+  var ice1Done = new Promise(r => ice1Finished = r);
+  var ice2Done = new Promise(r => ice2Finished = r);
+  var ice3Done = new Promise(r => ice3Finished = r);
+
+  var icsc = (pc, str, resolve) => {
+    var state = pc.iceConnectionState;
+    info(str + " ICE connection state is: " + state);
+    if (state == "connected") {
+      ok(true, str + " ICE connected");
+      resolve();
+    } else if (state == "failed") {
+      ok(false, str + " ICE failed")
+      resolve();
+    }
+  };
+
+  pc1.oniceconnectionstatechange = e => icsc(pc1, "PC1", ice1Finished);
+  pc2.oniceconnectionstatechange = e => icsc(pc2, "PC2", ice2Finished);
+  pc3.oniceconnectionstatechange = e => icsc(pc3, "PC3", ice3Finished);
+
+
+  async function getAnswer(pc, offer, answer) {
+    await pc.setLocalDescription(
+      await pc.createAnswer(
+        await pc.setRemoteDescription(offer)));
+    const sdplines = pc.localDescription.sdp.split('\r\n');
+    const fpIndex = sdplines.findIndex(l => l.match('^a=fingerprint'));
+    const FP = sdplines[fpIndex];
+    const audioIndex = sdplines.findIndex(l => l.match(/^m=audio [1-9]/));
+    const videoIndex = sdplines.findIndex(l => l.match(/^m=video [1-9]/));
+    if (audioIndex > -1) {
+      var ss = sdplines.slice(0, audioIndex);
+      ss.splice(fpIndex, 1);
+      answer.sessionSection = ss;
+      const rejectedVideoIndex = sdplines.findIndex(l => l.match('m=video 0'));
+      var ams = sdplines.slice(audioIndex, rejectedVideoIndex);
+      ams.push(FP);
+      ams.push(fakeFingerPrint);
+      answer.audioMsection = ams;
+    }
+    if (videoIndex > -1) {
+      var vms = sdplines.slice(videoIndex, sdplines.length -1);
+      vms.push(fakeFingerPrint);
+      vms.push(FP);
+      answer.videoMsection = vms;
+    }
+    return answer;
+  }
+
+  runNetworkTest(function() {
+    var v1 = createMediaElement('video', 'v1');
+    var v2 = createMediaElement('video', 'v2');
+    var v3 = createMediaElement('video', 'v3');
+    var offer, offerVideo, offerAudio;
+
+    navigator.mediaDevices.getUserMedia({ video: true, audio: true })
+    .then(stream => (v1.srcObject = stream).getTracks().forEach(t => pc1.addTrack(t, stream)))
+    .then(() => navigator.mediaDevices.getUserMedia({ video: true }))
+    .then(stream2 => (v2.srcObject = stream2).getTracks().forEach(t => pc2.addTrack(t, stream2)))
+    .then(() => navigator.mediaDevices.getUserMedia({ audio: true }))
+    .then(stream3 => (v3.srcObject = stream3).getTracks().forEach(t => pc3.addTrack(t, stream3)))
+    .then(() => pc1.createOffer())
+    .then(offer => pc1.setLocalDescription(offer))
+    .then(() => {
+      offer = pc1.localDescription;
+      //info("Original OFFER: " + JSON.stringify(offer));
+      offer.sdp = sdputils.removeBundle(offer.sdp);
+      //info("OFFER w/o BUNDLE: " + JSON.stringify(offer));
+      offerAudio = new RTCSessionDescription(JSON.parse(JSON.stringify(offer)));
+      offerAudio.sdp = offerAudio.sdp.replace('m=video 9', 'm=video 0');
+      //info("offerAudio: " + JSON.stringify(offerAudio));
+      offerVideo = new RTCSessionDescription(JSON.parse(JSON.stringify(offer)));
+      offerVideo.sdp = offerVideo.sdp.replace('m=audio 9', 'm=audio 0');
+      //info("offerVideo: " + JSON.stringify(offerVideo));
+    })
+    .then(() => {
+      return getAnswer(pc2, offerVideo, {});
+    })
+    .then((partialAnswer) => {
+      return getAnswer(pc3, offerAudio, partialAnswer);
+    })
+    .then((answer) => {
+      var fakeAnswer = answer.sessionSection.concat(answer.audioMsection, answer.videoMsection).join('\r\n');
+      info("ANSWER: " + fakeAnswer);
+      pc1.setRemoteDescription({type: 'answer', sdp: fakeAnswer});
+    })
+
+    .then(() => Promise.all([ice1Done, ice2Done, ice3Done]))
+    .then(() => ok(true, "Connected."))
+    .catch(reason => ok(false, "unexpected failure: " + reason))
+    .then(networkTestFinished);
+  });
+</script>
+</pre>
+</body>
+</html>
--- a/dom/webidl/Window.webidl
+++ b/dom/webidl/Window.webidl
@ -534,10 +534,12 @@ partial interface Window {
  [Func="IsChromeOrXBL"]
  sequence<DOMString> getAppLocales();

+#ifdef ENABLE_INTL_API
  /**
   * Getter funcion for IntlUtils, which provides helper functions for
   * localization.
   */
  [Throws, Func="IsChromeOrXBL"]
  readonly attribute IntlUtils intlUtils;
+#endif
 };
--- a/dom/webidl/moz.build
+++ b/dom/webidl/moz.build
@ -649,7 +649,6 @@ WEBIDL_FILES = [
    'InputEvent.webidl',
    'InspectorUtils.webidl',
    'IntersectionObserver.webidl',
-    'IntlUtils.webidl',
    'IterableIterator.webidl',
    'KeyAlgorithm.webidl',
    'KeyboardEvent.webidl',
@ -1136,3 +1135,8 @@ if CONFIG['ACCESSIBILITY']:
    WEBIDL_FILES += [
        'AccessibleNode.webidl',
    ]
+
+if CONFIG['ENABLE_INTL_API']:
+    WEBIDL_FILES += [
+        'IntlUtils.webidl',
+    ]
--- a/editor/libeditor/EditorBase.h
+++ b/editor/libeditor/EditorBase.h
@ -113,12 +113,14 @@ class DeleteNodeTransaction;
 class DeleteTextTransaction;
 class EditAggregateTransaction;
 class ErrorResult;
+class HTMLEditor;
 class InsertNodeTransaction;
 class InsertTextTransaction;
 class JoinNodeTransaction;
 class RemoveStyleSheetTransaction;
 class SplitNodeTransaction;
 class TextComposition;
+class TextEditor;
 struct EditorDOMPoint;

 namespace dom {
@ -164,6 +166,11 @@ public:
   */
  EditorBase();

+  virtual TextEditor* AsTextEditor() = 0;
+  virtual const TextEditor* AsTextEditor() const = 0;
+  virtual HTMLEditor* AsHTMLEditor() = 0;
+  virtual const HTMLEditor* AsHTMLEditor() const = 0;
+
 protected:
  /**
   * The default destructor. This should suffice. Should this be pure virtual
--- a/editor/libeditor/HTMLEditRules.cpp
+++ b/editor/libeditor/HTMLEditRules.cpp
@ -241,9 +241,16 @@ NS_IMPL_CYCLE_COLLECTION_INHERITED(HTMLEditRules, TextEditRules,
 NS_IMETHODIMP
 HTMLEditRules::Init(TextEditor* aTextEditor)
 {
+  if (NS_WARN_IF(!aTextEditor)) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
  InitFields();

-  mHTMLEditor = static_cast<HTMLEditor*>(aTextEditor);
+  mHTMLEditor = aTextEditor->AsHTMLEditor();
+  if (NS_WARN_IF(!mHTMLEditor)) {
+    return NS_ERROR_INVALID_ARG;
+  }

  // call through to base class Init
  nsresult rv = TextEditRules::Init(aTextEditor);
--- a/editor/libeditor/HTMLEditor.cpp
+++ b/editor/libeditor/HTMLEditor.cpp
@ -510,7 +510,7 @@ HTMLEditor::InitRules()
    // instantiate the rules for the html editor
    mRules = new HTMLEditRules();
  }
-  return mRules->Init(static_cast<TextEditor*>(this));
+  return mRules->Init(this);
 }

 NS_IMETHODIMP
--- a/editor/libeditor/HTMLEditor.h
+++ b/editor/libeditor/HTMLEditor.h
@ -99,6 +99,9 @@ public:

  HTMLEditor();

+  virtual HTMLEditor* AsHTMLEditor() override { return this; }
+  virtual const HTMLEditor* AsHTMLEditor() const override { return this; }
+
  bool GetReturnInParagraphCreatesNewParagraph();
  Element* GetSelectionContainer();

--- a/editor/libeditor/HTMLEditorEventListener.cpp
+++ b/editor/libeditor/HTMLEditorEventListener.cpp
@ -30,24 +30,18 @@ namespace mozilla {

 using namespace dom;

-#ifdef DEBUG
 nsresult
 HTMLEditorEventListener::Connect(EditorBase* aEditorBase)
 {
-  nsCOMPtr<nsIHTMLEditor> htmlEditor = do_QueryObject(aEditorBase);
-  nsCOMPtr<nsIHTMLInlineTableEditor> htmlInlineTableEditor =
-    do_QueryObject(aEditorBase);
-  NS_PRECONDITION(htmlEditor && htmlInlineTableEditor,
-                  "Set HTMLEditor or its sub class");
-  return EditorEventListener::Connect(aEditorBase);
-}
-#endif
-
-HTMLEditor*
-HTMLEditorEventListener::GetHTMLEditor()
-{
-  // mEditor must be HTMLEditor or its subclass.
-  return static_cast<HTMLEditor*>(mEditorBase);
+  if (NS_WARN_IF(!aEditorBase)) {
+    return NS_ERROR_INVALID_ARG;
+  }
+  // Guarantee that mEditorBase is always HTMLEditor.
+  HTMLEditor* htmlEditor = aEditorBase->AsHTMLEditor();
+  if (NS_WARN_IF(!htmlEditor)) {
+    return NS_ERROR_INVALID_ARG;
+  }
+  return EditorEventListener::Connect(htmlEditor);
 }

 nsresult
@ -59,7 +53,8 @@ HTMLEditorEventListener::MouseUp(nsIDOMMouseEvent* aMouseEvent)

  // FYI: We need to notify HTML editor of mouseup even if it's consumed
  //      because HTML editor always needs to release grabbing resizer.
-  HTMLEditor* htmlEditor = GetHTMLEditor();
+  HTMLEditor* htmlEditor = mEditorBase->AsHTMLEditor();
+  MOZ_ASSERT(htmlEditor);

  nsCOMPtr<nsIDOMEventTarget> target;
  nsresult rv = aMouseEvent->AsEvent()->GetTarget(getter_AddRefs(target));
@ -93,7 +88,9 @@ HTMLEditorEventListener::MouseDown(nsIDOMMouseEvent* aMouseEvent)
  WidgetMouseEvent* mousedownEvent =
    aMouseEvent->AsEvent()->WidgetEventPtr()->AsMouseEvent();

-  HTMLEditor* htmlEditor = GetHTMLEditor();
+  HTMLEditor* htmlEditor = mEditorBase->AsHTMLEditor();
+  MOZ_ASSERT(htmlEditor);
+
  // Contenteditable should disregard mousedowns outside it.
  // IsAcceptableInputEvent() checks it for a mouse event.
  if (!htmlEditor->IsAcceptableInputEvent(mousedownEvent)) {
@ -222,13 +219,19 @@ HTMLEditorEventListener::MouseDown(nsIDOMMouseEvent* aMouseEvent)
 nsresult
 HTMLEditorEventListener::MouseClick(nsIDOMMouseEvent* aMouseEvent)
 {
+  if (NS_WARN_IF(DetachedFromEditor())) {
+    return NS_OK;
+  }
+
  nsCOMPtr<nsIDOMEventTarget> target;
  nsresult rv = aMouseEvent->AsEvent()->GetTarget(getter_AddRefs(target));
  NS_ENSURE_SUCCESS(rv, rv);
  NS_ENSURE_TRUE(target, NS_ERROR_NULL_POINTER);
  nsCOMPtr<nsIDOMElement> element = do_QueryInterface(target);

-  GetHTMLEditor()->DoInlineTableEditingAction(element);
+  HTMLEditor* htmlEditor = mEditorBase->AsHTMLEditor();
+  MOZ_ASSERT(htmlEditor);
+  htmlEditor->DoInlineTableEditingAction(element);

  return EditorEventListener::MouseClick(aMouseEvent);
 }
--- a/editor/libeditor/HTMLEditorEventListener.h
+++ b/editor/libeditor/HTMLEditorEventListener.h
@ -25,17 +25,15 @@ public:
  {
  }

-#ifdef DEBUG
-  // WARNING: You must be use HTMLEditor or its sub class for this class.
+  /**
+   * Connect() fails if aEditorBase isn't an HTMLEditor instance.
+   */
  virtual nsresult Connect(EditorBase* aEditorBase) override;
-#endif

 protected:
  virtual nsresult MouseDown(nsIDOMMouseEvent* aMouseEvent) override;
  virtual nsresult MouseUp(nsIDOMMouseEvent* aMouseEvent) override;
  virtual nsresult MouseClick(nsIDOMMouseEvent* aMouseEvent) override;
-
-  inline HTMLEditor* GetHTMLEditor();
 };

 } // namespace mozilla
--- a/editor/libeditor/TextEditor.cpp
+++ b/editor/libeditor/TextEditor.cpp
@ -10,6 +10,7 @@
 #include "gfxFontUtils.h"
 #include "mozilla/Assertions.h"
 #include "mozilla/EditorUtils.h" // AutoEditBatch, AutoRules
+#include "mozilla/HTMLEditor.h"
 #include "mozilla/mozalloc.h"
 #include "mozilla/Preferences.h"
 #include "mozilla/TextEditRules.h"
@ -78,6 +79,18 @@ TextEditor::TextEditor()
  GetDefaultEditorPrefs(mNewlineHandling, mCaretStyle);
 }

+HTMLEditor*
+TextEditor::AsHTMLEditor()
+{
+  return nullptr;
+}
+
+const HTMLEditor*
+TextEditor::AsHTMLEditor() const
+{
+  return nullptr;
+}
+
 TextEditor::~TextEditor()
 {
  // Remove event listeners. Note that if we had an HTML editor,
--- a/editor/libeditor/TextEditor.h
+++ b/editor/libeditor/TextEditor.h
@ -56,6 +56,11 @@ public:

  TextEditor();

+  virtual TextEditor* AsTextEditor() override { return this; }
+  virtual const TextEditor* AsTextEditor() const override { return this; }
+  virtual HTMLEditor* AsHTMLEditor() override;
+  virtual const HTMLEditor* AsHTMLEditor() const override;
+
  // nsIPlaintextEditor methods
  NS_DECL_NSIPLAINTEXTEDITOR

--- a/gfx/thebes/gfxAndroidPlatform.h
+++ b/gfx/thebes/gfxAndroidPlatform.h
@ -66,10 +66,6 @@ public:

    virtual already_AddRefed<mozilla::gfx::VsyncSource> CreateHardwareVsyncSource() override;

-    virtual bool SupportsApzTouchInput() const override {
-      return true;
-    }
-
 protected:
    bool AccelerateLayersByDefault() override {
      return true;
--- a/gfx/thebes/gfxFont.cpp
+++ b/gfx/thebes/gfxFont.cpp
@ -3642,7 +3642,7 @@ gfxFont::SanitizeMetrics(gfxFont::Metrics *aMetrics, bool aIsBadUnderlineFont)
 // usual font tables (which can happen in the case of a legacy bitmap or Type1
 // font for which the platform-specific backend used platform APIs instead of
 // sfnt tables to create the horizontal metrics).
-const gfxFont::Metrics*
+UniquePtr<const gfxFont::Metrics>
 gfxFont::CreateVerticalMetrics()
 {
    const uint32_t kHheaTableTag = TRUETYPE_TAG('h','h','e','a');
@ -3651,8 +3651,8 @@ gfxFont::CreateVerticalMetrics()
    const uint32_t kOS_2TableTag = TRUETYPE_TAG('O','S','/','2');
    uint32_t len;

-    Metrics* metrics = new Metrics;
-    ::memset(metrics, 0, sizeof(Metrics));
+    UniquePtr<Metrics> metrics = MakeUnique<Metrics>();
+    ::memset(metrics.get(), 0, sizeof(Metrics));

    // Some basic defaults, in case the font lacks any real metrics tables.
    // TODO: consider what rounding (if any) we should apply to these.
@ -3797,7 +3797,7 @@ gfxFont::CreateVerticalMetrics()
    metrics->xHeight = metrics->emHeight / 2;
    metrics->capHeight = metrics->maxAscent;

-    return metrics;
+    return Move(metrics);
 }

 gfxFloat
@ -3848,8 +3848,8 @@ void
 gfxFont::AddGlyphChangeObserver(GlyphChangeObserver *aObserver)
 {
    if (!mGlyphChangeObservers) {
-        mGlyphChangeObservers.reset(
-            new nsTHashtable<nsPtrHashKey<GlyphChangeObserver>>);
+        mGlyphChangeObservers =
+            MakeUnique<nsTHashtable<nsPtrHashKey<GlyphChangeObserver>>>();
    }
    mGlyphChangeObservers->PutEntry(aObserver);
 }
--- a/gfx/thebes/gfxFont.h
+++ b/gfx/thebes/gfxFont.h
@ -1551,7 +1551,7 @@ public:
            return GetHorizontalMetrics();
        }
        if (!mVerticalMetrics) {
-            mVerticalMetrics.reset(CreateVerticalMetrics());
+            mVerticalMetrics = CreateVerticalMetrics();
        }
        return *mVerticalMetrics;
    }
@ -1868,7 +1868,7 @@ public:
 protected:
    virtual const Metrics& GetHorizontalMetrics() = 0;

-    const Metrics* CreateVerticalMetrics();
+    mozilla::UniquePtr<const Metrics> CreateVerticalMetrics();

    // Output a single glyph at *aPt, which is updated by the glyph's advance.
    // Normal glyphs are simply accumulated in aBuffer until it is full and
--- a/gfx/thebes/gfxPlatform.cpp
+++ b/gfx/thebes/gfxPlatform.cpp
@ -137,6 +137,7 @@ class mozilla::gl::SkiaGLGlue : public GenericAtomicRefCounted {
 #include "SoftwareVsyncSource.h"
 #include "nscore.h" // for NS_FREE_PERMANENT_DATA
 #include "mozilla/dom/ContentChild.h"
+#include "mozilla/dom/TouchEvent.h"
 #include "gfxVR.h"
 #include "VRManagerChild.h"
 #include "mozilla/gfx/GPUParent.h"
@ -2644,6 +2645,12 @@ gfxPlatform::ImportGPUDeviceData(const mozilla::gfx::GPUDeviceData& aData)
  gfxConfig::ImportChange(Feature::OPENGL_COMPOSITING, aData.oglCompositing());
 }

+bool
+gfxPlatform::SupportsApzTouchInput() const
+{
+  return dom::TouchEvent::PrefEnabled(nullptr);
+}
+
 bool
 gfxPlatform::SupportsApzDragInput() const
 {
--- a/gfx/thebes/gfxPlatform.h
+++ b/gfx/thebes/gfxPlatform.h
@ -626,9 +626,7 @@ public:
    virtual bool SupportsApzWheelInput() const {
      return false;
    }
-    virtual bool SupportsApzTouchInput() const {
-      return false;
-    }
+    bool SupportsApzTouchInput() const;
    bool SupportsApzDragInput() const;

    virtual void FlushContentDrawing() {}
--- a/gfx/thebes/gfxPlatformGtk.cpp
+++ b/gfx/thebes/gfxPlatformGtk.cpp
@ -909,11 +909,4 @@ gfxPlatformGtk::CreateHardwareVsyncSource()
  return gfxPlatform::CreateHardwareVsyncSource();
 }

-bool
-gfxPlatformGtk::SupportsApzTouchInput() const
-{
-  int value = gfxPrefs::TouchEventsEnabled();
-  return value == 1 || value == 2;
-}
-
 #endif
--- a/gfx/thebes/gfxPlatformGtk.h
+++ b/gfx/thebes/gfxPlatformGtk.h
@ -123,8 +123,6 @@ public:
      return true;
    }

-    bool SupportsApzTouchInput() const override;
-
    void FontsPrefsChanged(const char *aPref) override;

    // maximum number of fonts to substitute for a generic
--- a/gfx/thebes/gfxWindowsPlatform.cpp
+++ b/gfx/thebes/gfxWindowsPlatform.cpp
@ -1878,13 +1878,6 @@ gfxWindowsPlatform::CreateHardwareVsyncSource()
  return d3dVsyncSource.forget();
 }

-bool
-gfxWindowsPlatform::SupportsApzTouchInput() const
-{
-  int value = gfxPrefs::TouchEventsEnabled();
-  return value == 1 || value == 2;
-}
-
 void
 gfxWindowsPlatform::GetAcceleratedCompositorBackends(nsTArray<LayersBackend>& aBackends)
 {
--- a/gfx/thebes/gfxWindowsPlatform.h
+++ b/gfx/thebes/gfxWindowsPlatform.h
@ -209,7 +209,6 @@ public:
    bool SupportsApzWheelInput() const override {
      return true;
    }
-    bool SupportsApzTouchInput() const override;

    // Recreate devices as needed for a device reset. Returns true if a device
    // reset occurred.
--- a/gfx/thebes/moz.build
+++ b/gfx/thebes/moz.build
@ -248,6 +248,7 @@ include('/ipc/chromium/chromium-config.mozbuild')
 FINAL_LIBRARY = 'xul'

 LOCAL_INCLUDES += [
+    '/dom/base',
    '/dom/workers',
    '/dom/xml',
 ]
--- a/image/test/reftest/downscaling/reftest-stylo.list
+++ b/image/test/reftest/downscaling/reftest-stylo.list
@ -27,12 +27,12 @@

 # RUN TESTS NOT AFFECTED BY DOWNSCALE-DURING-DECODE:
 # #
-fails == downscale-svg-1a.html downscale-svg-1a.html
-fails == downscale-svg-1b.html downscale-svg-1b.html
-fails == downscale-svg-1c.html downscale-svg-1c.html
-fails == downscale-svg-1d.html downscale-svg-1d.html
-fails == downscale-svg-1e.html downscale-svg-1e.html
-fails == downscale-svg-1f.html downscale-svg-1f.html
+== downscale-svg-1a.html downscale-svg-1a.html
+== downscale-svg-1b.html downscale-svg-1b.html
+== downscale-svg-1c.html downscale-svg-1c.html
+== downscale-svg-1d.html downscale-svg-1d.html
+== downscale-svg-1e.html downscale-svg-1e.html
+== downscale-svg-1f.html downscale-svg-1f.html

 # RUN TESTS WITH DOWNSCALE-DURING-DECODE DISABLED:
 # #
--- a/image/test/reftest/gif/reftest-stylo.list
+++ b/image/test/reftest/gif/reftest-stylo.list
@ -24,7 +24,7 @@ random == delaytest.html?transparent-animation.gif delaytest.html?transparent-an
 fails == one-color-offset.gif one-color-offset.gif

 # Bug 1068230
-fails == tile-transform.html tile-transform.html
+== tile-transform.html tile-transform.html

 # Bug 1234077
 == truncated-framerect.html truncated-framerect.html
--- a/intl/locale/LocaleService.cpp
+++ b/intl/locale/LocaleService.cpp
@ -8,6 +8,8 @@
 #include <algorithm>  // find_if()
 #include "mozilla/ClearOnShutdown.h"
 #include "mozilla/Services.h"
+#include "mozilla/Preferences.h"
+#include "mozilla/intl/OSPreferences.h"
 #include "nsIObserverService.h"
 #include "nsIToolkitChromeRegistry.h"

@ -15,9 +17,18 @@
 #include "unicode/uloc.h"
 #endif

+#define MATCH_OS_LOCALE_PREF "intl.locale.matchOS"
+#define SELECTED_LOCALE_PREF "general.useragent.locale"
+
+static const char* kObservedPrefs[] = {
+  MATCH_OS_LOCALE_PREF,
+  SELECTED_LOCALE_PREF,
+  nullptr
+};
+
 using namespace mozilla::intl;

-NS_IMPL_ISUPPORTS(LocaleService, mozILocaleService)
+NS_IMPL_ISUPPORTS(LocaleService, mozILocaleService, nsIObserver)

 mozilla::StaticRefPtr<LocaleService> LocaleService::sInstance;

@ -53,11 +64,21 @@ LocaleService::GetInstance()
 {
  if (!sInstance) {
    sInstance = new LocaleService();
+
+    // We're going to observe for requested languages changes which come
+    // from prefs.
+    DebugOnly<nsresult> rv = Preferences::AddStrongObservers(sInstance, kObservedPrefs);
+    MOZ_ASSERT(NS_SUCCEEDED(rv), "Adding observers failed.");
    ClearOnShutdown(&sInstance);
  }
  return sInstance;
 }

+LocaleService::~LocaleService()
+{
+  Preferences::RemoveObservers(sInstance, kObservedPrefs);
+}
+
 void
 LocaleService::GetAppLocales(nsTArray<nsCString>& aRetVal)
 {
@ -67,6 +88,43 @@ LocaleService::GetAppLocales(nsTArray<nsCString>& aRetVal)
  aRetVal = mAppLocales;
 }

+bool
+LocaleService::GetRequestedLocales(nsTArray<nsCString>& aRetVal)
+{
+  nsAutoCString locale;
+
+  nsCOMPtr<nsIPrefBranch> prefs(do_GetService("@mozilla.org/preferences-service;1"));
+
+  // First, we'll try to check if the user has `matchOS` pref selected
+  bool matchOSLocale = Preferences::GetBool(MATCH_OS_LOCALE_PREF);
+
+  if (matchOSLocale) {
+    // If he has, we'll pick the locale from the system
+    if (OSPreferences::GetInstance()->GetSystemLocales(aRetVal)) {
+      // If we succeeded, return.
+      return true;
+    }
+  }
+
+  // Otherwise, we'll try to get the requested locale from the prefs.
+
+  // In some cases, mainly on Fennec and on Linux version,
+  // `general.useragent.locale` is a special 'localized' value, like:
+  // "chrome://global/locale/intl.properties"
+  if (!NS_SUCCEEDED(Preferences::GetLocalizedCString(SELECTED_LOCALE_PREF, &locale))) {
+    // If not, we can attempt to retrieve it as a simple string value.
+    //rv = prefs->GetCharPref(SELECTED_LOCALE_PREF, getter_Copies(locale));
+    if (!NS_SUCCEEDED(Preferences::GetCString(SELECTED_LOCALE_PREF, &locale))) {
+      return false;
+    }
+  }
+
+  // At the moment we just take a single locale, but in the future
+  // we'll want to allow user to specify a list of requested locales.
+  aRetVal.AppendElement(locale);
+  return true;
+}
+
 void
 LocaleService::Refresh()
 {
@ -245,10 +303,37 @@ LocaleService::NegotiateLanguages(const nsTArray<nsCString>& aRequested,
  return true;
 }

+NS_IMETHODIMP
+LocaleService::Observe(nsISupports *aSubject, const char *aTopic,
+                      const char16_t *aData)
+{
+  // At the moment the only thing we're observing are settings indicating
+  // user requested locales.
+  NS_ConvertUTF16toUTF8 pref(aData);
+  if (pref.EqualsLiteral(MATCH_OS_LOCALE_PREF) || pref.EqualsLiteral(SELECTED_LOCALE_PREF)) {
+    nsCOMPtr<nsIObserverService> obs = mozilla::services::GetObserverService();
+    if (obs) {
+      obs->NotifyObservers(nullptr, "intl:requested-locales-changed", nullptr);
+    }
+  }
+  return NS_OK;
+}

 /**
 * mozILocaleService methods
 */
+
+static char**
+CreateOutArray(const nsTArray<nsCString>& aArray)
+{
+  uint32_t n = aArray.Length();
+  char** result = static_cast<char**>(moz_xmalloc(n * sizeof(char*)));
+  for (uint32_t i = 0; i < n; i++) {
+    result[i] = moz_xstrdup(aArray[i].get());
+  }
+  return result;
+}
+
 NS_IMETHODIMP
 LocaleService::GetAppLocales(uint32_t* aCount, char*** aOutArray)
 {
@ -257,11 +342,7 @@ LocaleService::GetAppLocales(uint32_t* aCount, char*** aOutArray)
  }

  *aCount = mAppLocales.Length();
-  *aOutArray = static_cast<char**>(moz_xmalloc(*aCount * sizeof(char*)));
-
-  for (uint32_t i = 0; i < *aCount; i++) {
-    (*aOutArray)[i] = moz_xstrdup(mAppLocales[i].get());
-  }
+  *aOutArray = CreateOutArray(mAppLocales);

  return NS_OK;
 }
@ -470,3 +551,20 @@ LocaleService::Locale::AddLikelySubtags()
  return false;
 #endif
 }
+
+NS_IMETHODIMP
+LocaleService::GetRequestedLocales(uint32_t* aCount, char*** aOutArray)
+{
+  AutoTArray<nsCString, 16> requestedLocales;
+  bool res = GetRequestedLocales(requestedLocales);
+
+  if (!res) {
+    NS_ERROR("Couldn't retrieve selected locales from prefs!");
+    return NS_ERROR_FAILURE;
+  }
+
+  *aCount = requestedLocales.Length();
+  *aOutArray = CreateOutArray(requestedLocales);
+
+  return NS_OK;
+}
--- a/intl/locale/LocaleService.h
+++ b/intl/locale/LocaleService.h
@ -7,6 +7,7 @@
 #define mozilla_intl_LocaleService_h__

 #include "mozilla/StaticPtr.h"
+#include "nsIObserver.h"
 #include "nsString.h"
 #include "nsTArray.h"

@ -37,10 +38,12 @@ namespace intl {
 * try to be specific when naming APIs, so the service is for locales,
 * but we negotiate between languages etc.
 */
-class LocaleService : public mozILocaleService
+class LocaleService : public mozILocaleService,
+                      public nsIObserver
 {
 public:
  NS_DECL_ISUPPORTS
+  NS_DECL_NSIOBSERVER
  NS_DECL_MOZILOCALESERVICE

  /**
@ -91,6 +94,26 @@ public:
   */
  void GetAppLocales(nsTArray<nsCString>& aRetVal);

+  /**
+   * Returns a list of locales that the user requested the app to be
+   * localized to.
+   *
+   * The result is a sorted list of valid locale IDs and it should be
+   * used as a requestedLocales input list for languages negotiation.
+   *
+   * Example: ["en-US", "de", "pl", "sr-Cyrl", "zh-Hans-HK"]
+   *
+   * Usage:
+   *   nsTArray<nsCString> appLocales;
+   *   LocaleService::GetInstance()->GetRequestedLocales(appLocales);
+   *
+   * Returns a boolean indicating if the attempt to retrieve prefs
+   * was successful.
+   *
+   * (See mozILocaleService.idl for a JS-callable version of this.)
+   */
+  bool GetRequestedLocales(nsTArray<nsCString>& aRetVal);
+
  /**
   * Triggers a refresh of the language negotiation process.
   *
@ -169,7 +192,7 @@ private:
                     LangNegStrategy aStrategy,
                     nsTArray<nsCString>& aRetVal);

-  virtual ~LocaleService() {};
+  virtual ~LocaleService();

  nsTArray<nsCString> mAppLocales;

--- a/intl/locale/mozILocaleService.idl
+++ b/intl/locale/mozILocaleService.idl
@ -108,4 +108,16 @@ interface mozILocaleService : nsISupports
   * Example: "zh-Hans-HK"
   */
  ACString getAppLocale();
+
+  /**
+   * Returns a list of locales that the user requested the app to be
+   * localized to.
+   *
+   * The result is an ordered list of locale IDs which should be
+   * used as a requestedLocales input list for language negotiation.
+   *
+   * Example: ["en-US", "de", "pl", "sr-Cyrl", "zh-Hans-HK"]
+   */
+  void getRequestedLocales([optional] out unsigned long aCount,
+                           [retval, array, size_is(aCount)] out string aLocales);
 };
--- a/intl/locale/tests/gtest/TestLocaleService.cpp
+++ b/intl/locale/tests/gtest/TestLocaleService.cpp
@ -40,6 +40,14 @@ TEST(Intl_Locale_LocaleService, GetAppLocales_lastIsEnUS) {
  ASSERT_TRUE(appLocales[len - 1].EqualsLiteral("en-US"));
 }

+TEST(Intl_Locale_LocaleService, GetRequestedLocales) {
+  nsTArray<nsCString> reqLocales;
+  LocaleService::GetInstance()->GetRequestedLocales(reqLocales);
+
+  int32_t len = reqLocales.Length();
+  ASSERT_TRUE(len > 0);
+}
+
 TEST(Intl_Locale_LocaleService, GetAppLocale) {
  nsTArray<nsCString> appLocales;
  LocaleService::GetInstance()->GetAppLocales(appLocales);
--- a/intl/locale/tests/unit/test_localeService.js
+++ b/intl/locale/tests/unit/test_localeService.js
@ -2,26 +2,130 @@
 * 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/. */

-/**
- * Make sure the locale service can be instantiated,
- * and returns something plausible for getAppLocale and getAppLocales.
- */
+const Cc = Components.classes;
+const Ci = Components.interfaces;
+const Cu = Components.utils;

+const { Services } = Cu.import('resource://gre/modules/Services.jsm', {});
+const osPrefs = Cc["@mozilla.org/intl/ospreferences;1"].
+  getService(Ci.mozIOSPreferences);
+
+/**
+ * Make sure the locale service can be instantiated.
+ */
 function run_test()
 {
-  var localeService =
+  const localeService =
    Components.classes["@mozilla.org/intl/localeservice;1"]
    .getService(Components.interfaces.mozILocaleService);

-  var appLocale = localeService.getAppLocale();
+  run_next_test();
+}
+
+add_test(function test_getAppLocales() {
+  const localeService =
+    Components.classes["@mozilla.org/intl/localeservice;1"]
+    .getService(Components.interfaces.mozILocaleService);
+
+  const appLocale = localeService.getAppLocale();
  do_check_true(appLocale != "", "appLocale is non-empty");

-  var appLocales = localeService.getAppLocales();
+  const appLocales = localeService.getAppLocales();
  do_check_true(Array.isArray(appLocales), "appLocales returns an array");

  do_check_true(appLocale == appLocales[0], "appLocale matches first entry in appLocales");

-  var enUScount = 0;
-  appLocales.forEach(function(loc) { if (loc == "en-US") { enUScount++; } });
-  do_check_true(enUScount == 1, "en-US is present exactly one time");
-}
+  const enUSLocales = appLocales.filter(loc => loc === "en-US");
+  do_check_true(enUSLocales.length == 1, "en-US is present exactly one time");
+
+  run_next_test();
+});
+
+const PREF_MATCH_OS_LOCALE = "intl.locale.matchOS";
+const PREF_SELECTED_LOCALE = "general.useragent.locale";
+const REQ_LOC_CHANGE_EVENT = "intl:requested-locales-changed";
+
+add_test(function test_getRequestedLocales() {
+  const localeService =
+    Components.classes["@mozilla.org/intl/localeservice;1"]
+    .getService(Components.interfaces.mozILocaleService);
+
+  const requestedLocales = localeService.getRequestedLocales();
+  do_check_true(Array.isArray(requestedLocales), "requestedLocales returns an array");
+
+  run_next_test();
+});
+
+/**
+ * In this test we verify that after we set an observer on the LocaleService
+ * event for requested locales change, it will be fired when the
+ * pref for matchOS is set to true.
+ *
+ * Then, we test that when the matchOS is set to true, we will retrieve
+ * OS locale from getRequestedLocales.
+ */
+add_test(function test_getRequestedLocales_matchOS() {
+  do_test_pending();
+
+  const localeService =
+    Components.classes["@mozilla.org/intl/localeservice;1"]
+    .getService(Components.interfaces.mozILocaleService);
+
+  Services.prefs.setBoolPref(PREF_MATCH_OS_LOCALE, false);
+  Services.prefs.setCharPref(PREF_SELECTED_LOCALE, "ar-IR");
+
+  const observer = {
+    observe: function (aSubject, aTopic, aData) {
+      switch (aTopic) {
+        case REQ_LOC_CHANGE_EVENT:
+          const reqLocs = localeService.getRequestedLocales();
+          do_check_true(reqLocs[0] === osPrefs.systemLocale);
+          Services.obs.removeObserver(observer, REQ_LOC_CHANGE_EVENT);
+          do_test_finished();
+      }
+    }
+  };
+
+  Services.obs.addObserver(observer, REQ_LOC_CHANGE_EVENT, false);
+  Services.prefs.setBoolPref(PREF_MATCH_OS_LOCALE, true);
+
+  run_next_test();
+});
+
+/**
+ * In this test we verify that after we set an observer on the LocaleService
+ * event for requested locales change, it will be fired when the
+ * pref for browser UI locale changes.
+ */
+add_test(function test_getRequestedLocales_matchOS() {
+  do_test_pending();
+
+  const localeService =
+    Components.classes["@mozilla.org/intl/localeservice;1"]
+    .getService(Components.interfaces.mozILocaleService);
+
+  Services.prefs.setBoolPref(PREF_MATCH_OS_LOCALE, false);
+  Services.prefs.setCharPref(PREF_SELECTED_LOCALE, "ar-IR");
+
+  const observer = {
+    observe: function (aSubject, aTopic, aData) {
+      switch (aTopic) {
+        case REQ_LOC_CHANGE_EVENT:
+          const reqLocs = localeService.getRequestedLocales();
+          do_check_true(reqLocs[0] === "sr-RU");
+          Services.obs.removeObserver(observer, REQ_LOC_CHANGE_EVENT);
+          do_test_finished();
+      }
+    }
+  };
+
+  Services.obs.addObserver(observer, REQ_LOC_CHANGE_EVENT, false);
+  Services.prefs.setCharPref(PREF_SELECTED_LOCALE, "sr-RU");
+
+  run_next_test();
+});
+
+do_register_cleanup(() => {
+    Services.prefs.clearUserPref(PREF_SELECTED_LOCALE);
+    Services.prefs.clearUserPref(PREF_MATCH_OS_LOCALE);
+});
--- a/ipc/glue/TaskFactory.h
+++ b/ipc/glue/TaskFactory.h
@ -58,22 +58,16 @@ public:
    return task.forget();
  }

-  template <class Method>
-  inline already_AddRefed<Runnable> NewRunnableMethod(Method method) {
-    typedef TaskWrapper<RunnableMethod<Method, Tuple0> > TaskWrapper;
+  template <class Method, typename... Args>
+  inline already_AddRefed<Runnable>
+  NewRunnableMethod(Method method, Args&&... args) {
+    typedef decltype(base::MakeTuple(mozilla::Forward<Args>(args)...)) ArgTuple;
+    typedef RunnableMethod<Method, ArgTuple> RunnableMethod;
+    typedef TaskWrapper<RunnableMethod> TaskWrapper;

-    RefPtr<TaskWrapper> task = new TaskWrapper(this, object_, method,
-                                               base::MakeTuple());
-
-    return task.forget();
-  }
-
-  template <class Method, class A>
-  inline already_AddRefed<Runnable> NewRunnableMethod(Method method, const A& a) {
-    typedef TaskWrapper<RunnableMethod<Method, Tuple1<A> > > TaskWrapper;
-
-    RefPtr<TaskWrapper> task = new TaskWrapper(this, object_, method,
-                                               base::MakeTuple(a));
+    RefPtr<TaskWrapper> task =
+      new TaskWrapper(this, object_, method,
+                      base::MakeTuple(mozilla::Forward<Args>(args)...));

    return task.forget();
  }
--- a/layout/base/ServoRestyleManager.cpp
+++ b/layout/base/ServoRestyleManager.cpp
@ -62,16 +62,6 @@ ServoRestyleManager::PostRestyleEvent(Element* aElement,
    aRestyleHint |= eRestyle_Self | eRestyle_Subtree;
  }

-  // XXX For now, convert eRestyle_Subtree into (eRestyle_Self |
-  // eRestyle_SomeDescendants), which Servo will interpret as
-  // RESTYLE_SELF | RESTYLE_DESCENDANTS, since this is a commonly
-  // posted restyle hint that doesn't yet align with RestyleHint's
-  // bits.
-  if (aRestyleHint & eRestyle_Subtree) {
-    aRestyleHint &= ~eRestyle_Subtree;
-    aRestyleHint |= eRestyle_Self | eRestyle_SomeDescendants;
-  }
-
  if (aRestyleHint || aMinChangeHint) {
    Servo_NoteExplicitHints(aElement, aRestyleHint, aMinChangeHint);
  }
--- a/layout/reftests/async-scrolling/reftest-stylo.list
+++ b/layout/reftests/async-scrolling/reftest-stylo.list
@ -1,14 +1,14 @@
 # DO NOT EDIT! This is a auto-generated temporary list for Stylo testing
-fails == bg-fixed-1.html bg-fixed-1.html
+== bg-fixed-1.html bg-fixed-1.html
 == bg-fixed-cover-1.html bg-fixed-cover-1.html
-fails == bg-fixed-cover-2.html bg-fixed-cover-2.html
+== bg-fixed-cover-2.html bg-fixed-cover-2.html
 skip-if(!asyncPan) == bg-fixed-cover-3.html bg-fixed-cover-3.html
 skip-if(!asyncPan) == bg-fixed-child.html bg-fixed-child.html
-fails == bg-fixed-child-clip-1.html bg-fixed-child-clip-1.html
-fails == bg-fixed-child-clip-2.html bg-fixed-child-clip-2.html
+== bg-fixed-child-clip-1.html bg-fixed-child-clip-1.html
+== bg-fixed-child-clip-2.html bg-fixed-child-clip-2.html
 fuzzy(1,246) fuzzy-if(skiaContent,2,160) fuzzy-if(browserIsRemote&&d2d,53,185) skip-if(!asyncPan) == bg-fixed-child-mask.html bg-fixed-child-mask.html
 == bg-fixed-in-opacity.html bg-fixed-in-opacity.html
-fails == bg-fixed-child-no-culling-1.html bg-fixed-child-no-culling-1.html
+== bg-fixed-child-no-culling-1.html bg-fixed-child-no-culling-1.html
 == bg-fixed-child-no-culling-2.html bg-fixed-child-no-culling-2.html
 fuzzy-if(Android,2,4000) fuzzy-if(browserIsRemote&&cocoaWidget,2,179524) fuzzy-if(browserIsRemote&&winWidget,1,74590) fuzzy-if(gtkWidget&&layersGPUAccelerated,1,3528) skip-if(!asyncPan) == bg-fixed-transformed-image.html bg-fixed-transformed-image.html
 == element-1.html element-1.html
--- a/layout/reftests/backgrounds/reftest-stylo.list
+++ b/layout/reftests/backgrounds/reftest-stylo.list
@ -8,26 +8,26 @@ include vector/reftest-stylo.list
 == layers-layer-count-cascade-2.xhtml layers-layer-count-cascade-2.xhtml
 fails == layers-layer-count-inheritance-2.xhtml layers-layer-count-inheritance-2.xhtml
 == viewport-translucent-color-1.html viewport-translucent-color-1.html
-fails == viewport-translucent-color-2.html viewport-translucent-color-2.html
-fails == viewport-translucent-color-3.html viewport-translucent-color-3.html
+== viewport-translucent-color-2.html viewport-translucent-color-2.html
+== viewport-translucent-color-3.html viewport-translucent-color-3.html
 == viewport-translucent-color-ref.html viewport-translucent-color-ref.html
 == iframe-translucent-color-1.html iframe-translucent-color-1.html
 == translucent-color-1.html translucent-color-1.html
-fails == translucent-color-2.html translucent-color-2.html
+== translucent-color-2.html translucent-color-2.html
 fuzzy-if(skiaContent,1,1024) == translucent-color-3.html translucent-color-3.html
 == translucent-color-ref.html translucent-color-ref.html
 == root-element-display-none-1.html root-element-display-none-1.html
-fails == continuous-inline-1a.html continuous-inline-1a.html
-fails == continuous-inline-1b.html continuous-inline-1b.html
-fails == continuous-inline-1c.html continuous-inline-1c.html
-fails == continuous-inline-1d.html continuous-inline-1d.html
-fails == continuous-inline-2a.html continuous-inline-2a.html
-fails == continuous-inline-2b.html continuous-inline-2b.html
-fails == continuous-inline-3.html continuous-inline-3.html
-fails == continuous-inline-4a.html continuous-inline-4a.html
-fails == continuous-inline-4b.html continuous-inline-4b.html
-fails == continuous-inline-5a.html continuous-inline-5a.html
-fails == continuous-inline-5b.html continuous-inline-5b.html
+== continuous-inline-1a.html continuous-inline-1a.html
+== continuous-inline-1b.html continuous-inline-1b.html
+== continuous-inline-1c.html continuous-inline-1c.html
+== continuous-inline-1d.html continuous-inline-1d.html
+== continuous-inline-2a.html continuous-inline-2a.html
+== continuous-inline-2b.html continuous-inline-2b.html
+== continuous-inline-3.html continuous-inline-3.html
+== continuous-inline-4a.html continuous-inline-4a.html
+== continuous-inline-4b.html continuous-inline-4b.html
+== continuous-inline-5a.html continuous-inline-5a.html
+== continuous-inline-5b.html continuous-inline-5b.html
 == background-redraw-237766.html background-redraw-237766.html

 == background-clip-1.html background-clip-1.html
@ -135,8 +135,8 @@ fails == background-moz-default-background-color.html background-moz-default-bac
 fails == fixed-bg-with-transform-outside-viewport-1.html fixed-bg-with-transform-outside-viewport-1.html
 fuzzy(2,83) == fixed-bg-border-radius.html fixed-bg-border-radius.html

-fails HTTP == root-background-1.html root-background-1.html
-fails HTTP == root-background-1.html root-background-1.html
+HTTP == root-background-1.html root-background-1.html
+HTTP == root-background-1.html root-background-1.html

 fails == really-big-background.html really-big-background.html # Bug 1341690
 fails == body-background.html body-background.html # Bug 1339711
--- a/layout/reftests/bugs/reftest-stylo.list
+++ b/layout/reftests/bugs/reftest-stylo.list
@ -441,8 +441,8 @@ fails == 331809-1.html 331809-1.html
 fails == 332557-1.html 332557-1.html
 == 332975-1.html 332975-1.html
 == 333970-1.html 333970-1.html
-== 334829-1a.xhtml 334829-1a.xhtml
-== 334829-1b.xhtml 334829-1b.xhtml
+fails == 334829-1a.xhtml 334829-1a.xhtml
+fails == 334829-1b.xhtml 334829-1b.xhtml
 fails == 335628-1.html 335628-1.html
 == 335628-2.xul 335628-2.xul
 == 336096-1.xul 336096-1.xul
@ -601,10 +601,10 @@ fails == 367247-l-scroll.html 367247-l-scroll.html
 == 367612-1e.html 367612-1e.html
 == 367612-1f.html 367612-1f.html
 == 367612-1g.html 367612-1g.html
-fails == 368020-1.html 368020-1.html
-fails == 368020-2.html 368020-2.html
-fails == 368020-3.html 368020-3.html
-fails pref(layout.css.box-decoration-break.enabled,true) == 368020-5.html 368020-5.html
+random == 368020-1.html 368020-1.html
+== 368020-2.html 368020-2.html
+== 368020-3.html 368020-3.html
+pref(layout.css.box-decoration-break.enabled,true) == 368020-5.html 368020-5.html
 == 368155-1.xhtml 368155-1.xhtml
 asserts(4-8) == 368155-negative-margins-1.html 368155-negative-margins-1.html
 # we can't test this because there's antialiasing involved, and our comparison
@ -999,7 +999,7 @@ fails == 419531-1.html 419531-1.html
 == 420069-1.html 420069-1.html
 == 420069-2.html 420069-2.html
 == 420351-1.html 420351-1.html
-fails == 420790-1.xhtml 420790-1.xhtml
+== 420790-1.xhtml 420790-1.xhtml
 == 421069.html 421069.html
 == 421069.html 421069.html
 == 421069-ref.html 421069-ref.html
@ -1211,21 +1211,21 @@ fails == 456330-1.gif 456330-1.gif
 fails == 458296-1b.html 458296-1b.html
 fails == 458296-1c.html 458296-1c.html
 fails == 458296-1d.html 458296-1d.html
-fails == 458487-1a.html 458487-1a.html
-fails == 458487-1b.html 458487-1b.html
-fails == 458487-1c.html 458487-1c.html
-fails == 458487-1d.html 458487-1d.html
-fails == 458487-1e.html 458487-1e.html
-fails == 458487-1f.html 458487-1f.html
-fails == 458487-1g.html 458487-1g.html
-fails == 458487-1h.html 458487-1h.html
+== 458487-1a.html 458487-1a.html
+== 458487-1b.html 458487-1b.html
+== 458487-1c.html 458487-1c.html
+== 458487-1d.html 458487-1d.html
+== 458487-1e.html 458487-1e.html
+== 458487-1f.html 458487-1f.html
+== 458487-1g.html 458487-1g.html
+== 458487-1h.html 458487-1h.html
 == 458487-2.html 458487-2.html
 == 458487-3.html 458487-3.html
-fails == 458487-4a.html 458487-4a.html
-fails == 458487-4b.html 458487-4b.html
-fails == 458487-4c.html 458487-4c.html
-fails == 458487-5a.html 458487-5a.html
-fails == 458487-5b.html 458487-5b.html
+== 458487-4a.html 458487-4a.html
+== 458487-4b.html 458487-4b.html
+== 458487-4c.html 458487-4c.html
+== 458487-5a.html 458487-5a.html
+== 458487-5b.html 458487-5b.html
 == 459443-1.html 459443-1.html
 == 459613-1.html 459613-1.html
 == 460012-1.html 460012-1.html
@ -1237,10 +1237,10 @@ fails == 458487-5b.html 458487-5b.html
 == 462844-4.html 462844-4.html
 == 463204-1.html 463204-1.html
 == 463217-1.xul 463217-1.xul
-fails == 463952-1.html 463952-1.html
-fails == 464811-1.html 464811-1.html
+== 463952-1.html 463952-1.html
+== 464811-1.html 464811-1.html
 == 465574-1.html 465574-1.html
-fails == 466258-1.html 466258-1.html
+== 466258-1.html 466258-1.html
 == 466395-1.html 466395-1.html
 == 466395-2.html 466395-2.html
 fails == 467084-1.html 467084-1.html
@ -1642,10 +1642,10 @@ fails == 617242-1.html 617242-1.html
 fails == 618071.html 618071.html
 fails == 619117-1.html 619117-1.html
 fails HTTP(..) == 619511-1.html 619511-1.html
-fails == 621253-1-externalFilter.html 621253-1-externalFilter.html
-fails == 621253-1-internalFilter.html 621253-1-internalFilter.html
-fails HTTP(..) == 621253-2-externalFilter.html 621253-2-externalFilter.html
-fails == 621253-2-internalFilter.html 621253-2-internalFilter.html
+== 621253-1-externalFilter.html 621253-1-externalFilter.html
+== 621253-1-internalFilter.html 621253-1-internalFilter.html
+HTTP(..) == 621253-2-externalFilter.html 621253-2-externalFilter.html
+== 621253-2-internalFilter.html 621253-2-internalFilter.html
 random-if(winWidget) fuzzy-if(OSX==1008,19,17) == 621918-1.svg 621918-1.svg
 random-if(winWidget) HTTP(..) == 621918-2.svg 621918-2.svg
 fails == 622585-1.html 622585-1.html
@ -1834,7 +1834,7 @@ fails == 1018522-1.html 1018522-1.html
 == 1021564-2.html 1021564-2.html
 == 1021564-3.html 1021564-3.html
 == 1021564-4.html 1021564-4.html
-fails pref(browser.display.use_document_fonts,0) == 1022481-1.html 1022481-1.html
+pref(browser.display.use_document_fonts,0) == 1022481-1.html 1022481-1.html
 == 1022612-1.html 1022612-1.html
 == 1024473-1.html 1024473-1.html
 == 1025914-1.html 1025914-1.html
--- a/layout/reftests/css-valuesandunits/reftest-stylo.list
+++ b/layout/reftests/css-valuesandunits/reftest-stylo.list
@ -7,8 +7,8 @@
 == unit-rem-root-fontsize.html unit-rem-root-fontsize.html
 fails == unit-rem-root-width.html unit-rem-root-width.html
 == unit-rem.svg unit-rem.svg
-fails == unit-vh-vw.html unit-vh-vw.html
-fails == unit-vh-vw-zoom.html unit-vh-vw-zoom.html
+== unit-vh-vw.html unit-vh-vw.html
+random == unit-vh-vw-zoom.html unit-vh-vw-zoom.html
 fails == unit-vh-vw-overflow-auto.html unit-vh-vw-overflow-auto.html
 fails == unit-vh-vw-overflow-scroll.html unit-vh-vw-overflow-scroll.html
 fails == unit-vh-vw-overflow-scroll-x.html unit-vh-vw-overflow-scroll-x.html
--- a/layout/reftests/dom/reftest-stylo.list
+++ b/layout/reftests/dom/reftest-stylo.list
@ -32,7 +32,7 @@
 == insertmultiplemultiple-2.html insertmultiplemultiple-2.html

 # testing bindings that have multiple insertion points
-fails == multipleinsertionpoints-ref2.xhtml multipleinsertionpoints-ref2.xhtml
+== multipleinsertionpoints-ref2.xhtml multipleinsertionpoints-ref2.xhtml
 # append a single element
 fails == multipleinsertionpoints-appendsingle-1.xhtml multipleinsertionpoints-appendsingle-1.xhtml
 fails == multipleinsertionpoints-appendsingle-2.xhtml multipleinsertionpoints-appendsingle-2.xhtml
--- a/layout/reftests/font-inflation/reftest-stylo.list
+++ b/layout/reftests/font-inflation/reftest-stylo.list
@ -63,7 +63,7 @@ pref(font.size.inflation.emPerLine,15) pref(font.size.inflation.forceEnabled,tru
 pref(font.size.inflation.emPerLine,15) pref(font.size.inflation.forceEnabled,true) pref(font.size.inflation.lineThreshold,0) == disable-fontinfl-on-mobile-2.html disable-fontinfl-on-mobile-2.html
 pref(font.size.inflation.emPerLine,15) pref(font.size.inflation.forceEnabled,true) pref(font.size.inflation.lineThreshold,0) == disable-fontinfl-on-mobile-3.html disable-fontinfl-on-mobile-3.html
 pref(font.size.inflation.emPerLine,15) pref(font.size.inflation.forceEnabled,true) pref(font.size.inflation.lineThreshold,0) == disable-fontinfl-on-mobile-5.html disable-fontinfl-on-mobile-5.html
-fails pref(font.size.inflation.emPerLine,15) pref(font.size.inflation.forceEnabled,true) pref(font.size.inflation.lineThreshold,0) == preformatted-text.html preformatted-text.html
+pref(font.size.inflation.emPerLine,15) pref(font.size.inflation.forceEnabled,true) pref(font.size.inflation.lineThreshold,0) == preformatted-text.html preformatted-text.html
 pref(font.size.inflation.emPerLine,15) pref(font.size.inflation.forceEnabled,true) pref(font.size.inflation.lineThreshold,0) == fixed-height-body.html fixed-height-body.html
 pref(font.size.inflation.emPerLine,15) pref(font.size.inflation.forceEnabled,true) pref(font.size.inflation.lineThreshold,0) == fixed-height-body-child.html fixed-height-body-child.html
 pref(font.size.inflation.emPerLine,15) pref(font.size.inflation.forceEnabled,true) pref(font.size.inflation.lineThreshold,0) == consecutive-inline.html consecutive-inline.html
--- a/layout/reftests/scrolling/reftest-stylo.list
+++ b/layout/reftests/scrolling/reftest-stylo.list
@ -1,11 +1,11 @@
 # DO NOT EDIT! This is a auto-generated temporary list for Stylo testing
 HTTP == deferred-anchor.xhtml#d deferred-anchor-ref.xhtml#d
 fuzzy-if(xulRuntime.widgetToolkit=="gtk3",1,23) == deferred-anchor2.xhtml deferred-anchor2.xhtml
-fails HTTP == fixed-1.html fixed-1.html
-fails == fixed-table-1.html fixed-table-1.html
-fails HTTP == fixed-opacity-1.html fixed-opacity-1.html
-fails HTTP == fixed-opacity-2.html fixed-opacity-2.html
-fails == fixed-text-1.html fixed-text-1.html
+HTTP == fixed-1.html fixed-1.html
+random == fixed-table-1.html fixed-table-1.html
+HTTP == fixed-opacity-1.html fixed-opacity-1.html
+HTTP == fixed-opacity-2.html fixed-opacity-2.html
+== fixed-text-1.html fixed-text-1.html
 HTTP == fixed-text-2.html fixed-text-2.html
 fails == iframe-border-radius.html iframe-border-radius.html
 == image-1.html image-1.html
@ -22,7 +22,7 @@ fails == scroll-behavior-8.html scroll-behavior-8.html
 fails == scroll-behavior-9.html scroll-behavior-9.html
 skip-if(Android) pref(layout.css.scroll-behavior.enabled,true) pref(layout.css.scroll-behavior.property-enabled,true) == scroll-behavior-10.html scroll-behavior-10.html
 fails == scroll-behavior-textarea.html scroll-behavior-textarea.html
-fails HTTP == simple-1.html simple-1.html
+HTTP == simple-1.html simple-1.html
 fails HTTP == subpixel-1.html#d subpixel-1-ref.html#d
 == text-1.html text-1.html
 == text-2.html?up text-2.html?up
--- a/layout/reftests/svg/as-image/reftest-stylo.list
+++ b/layout/reftests/svg/as-image/reftest-stylo.list
@ -6,17 +6,17 @@ include zoom/reftest-stylo.list

 # Background-image tests
 == background-display-none-1.html background-display-none-1.html
-fails == background-simple-1.html background-simple-1.html
-fails == background-simple-2.html background-simple-2.html
+== background-simple-1.html background-simple-1.html
+== background-simple-2.html background-simple-2.html

 # Sightly trickier background-image test
-fails == background-viewBox-1.html background-viewBox-1.html
+== background-viewBox-1.html background-viewBox-1.html

 # background tests with the background area getting resized
-fails == background-resize-1.html background-resize-1.html
-fails == background-resize-2.html background-resize-2.html
-fails == background-resize-3.html background-resize-3.html
-fails == background-resize-4.html background-resize-4.html
+== background-resize-1.html background-resize-1.html
+== background-resize-2.html background-resize-2.html
+== background-resize-3.html background-resize-3.html
+== background-resize-4.html background-resize-4.html

 # Test for stretching background images by different amounts in each dimension
 == background-stretch-1.html background-stretch-1.html
--- a/layout/reftests/svg/svg-integration/reftest-stylo.list
+++ b/layout/reftests/svg/svg-integration/reftest-stylo.list
@ -2,21 +2,21 @@
 # clip-path tests
 include clip-path/reftest-stylo.list

-fails == clipPath-html-01.xhtml clipPath-html-01.xhtml
-fails == clipPath-html-01-extref.xhtml clipPath-html-01-extref.xhtml
-fails == clipPath-html-02.xhtml clipPath-html-02.xhtml
-fails == clipPath-html-02-extref.xhtml clipPath-html-02-extref.xhtml
-fails == clipPath-html-03.xhtml clipPath-html-03.xhtml
-fails == clipPath-html-03-extref.xhtml clipPath-html-03-extref.xhtml
-fails == clipPath-html-04.xhtml clipPath-html-04.xhtml
-fails == clipPath-html-04-extref.xhtml clipPath-html-04-extref.xhtml
-fails == clipPath-html-05.xhtml clipPath-html-05.xhtml
-fails == clipPath-html-05-extref.xhtml clipPath-html-05-extref.xhtml
-fails == clipPath-html-06.xhtml clipPath-html-06.xhtml
-fails == clipPath-html-06-extref.xhtml clipPath-html-06-extref.xhtml
+== clipPath-html-01.xhtml clipPath-html-01.xhtml
+== clipPath-html-01-extref.xhtml clipPath-html-01-extref.xhtml
+== clipPath-html-02.xhtml clipPath-html-02.xhtml
+== clipPath-html-02-extref.xhtml clipPath-html-02-extref.xhtml
+== clipPath-html-03.xhtml clipPath-html-03.xhtml
+== clipPath-html-03-extref.xhtml clipPath-html-03-extref.xhtml
+== clipPath-html-04.xhtml clipPath-html-04.xhtml
+== clipPath-html-04-extref.xhtml clipPath-html-04-extref.xhtml
+== clipPath-html-05.xhtml clipPath-html-05.xhtml
+== clipPath-html-05-extref.xhtml clipPath-html-05-extref.xhtml
+== clipPath-html-06.xhtml clipPath-html-06.xhtml
+== clipPath-html-06-extref.xhtml clipPath-html-06-extref.xhtml
 == clipPath-html-07.xhtml clipPath-html-07.xhtml
-fails == clipPath-html-08.xhtml clipPath-html-08.xhtml
-fails == clipPath-html-zoomed-01.xhtml clipPath-html-zoomed-01.xhtml
+== clipPath-html-08.xhtml clipPath-html-08.xhtml
+== clipPath-html-zoomed-01.xhtml clipPath-html-zoomed-01.xhtml
 == clipPath-transformed-html-01.xhtml clipPath-transformed-html-01.xhtml
 == clipPath-transformed-html-02.xhtml clipPath-transformed-html-02.xhtml
 == conditions-outer-svg-01.xhtml conditions-outer-svg-01.xhtml
@ -25,9 +25,9 @@ fails == dynamic-conditions-outer-svg-01.xhtml dynamic-conditions-outer-svg-01.x
 fails == dynamic-conditions-outer-svg-02.xhtml dynamic-conditions-outer-svg-02.xhtml
 fails == dynamic-conditions-outer-svg-03.xhtml dynamic-conditions-outer-svg-03.xhtml
 == dynamic-conditions-outer-svg-04.xhtml dynamic-conditions-outer-svg-04.xhtml
-fails == filter-html-01.xhtml filter-html-01.xhtml
-fails == filter-html-01-extref.xhtml filter-html-01-extref.xhtml
-fails == filter-html-zoomed-01.xhtml filter-html-zoomed-01.xhtml
+== filter-html-01.xhtml filter-html-01.xhtml
+random == filter-html-01-extref.xhtml filter-html-01-extref.xhtml
+== filter-html-zoomed-01.xhtml filter-html-zoomed-01.xhtml
 fails == mask-html-01.xhtml mask-html-01.xhtml
 fails == mask-html-01-extref-01.xhtml mask-html-01-extref-01.xhtml
 random == mask-html-01-extref-02.xhtml mask-html-01-extref-02.xhtml
--- a/layout/reftests/text/reftest-stylo.list
+++ b/layout/reftests/text/reftest-stylo.list
@ -131,8 +131,8 @@ fails == wordwrap-03.html wordwrap-03.html
 == overflowwrap-04.html overflowwrap-04.html
 fails == wordwrap-05.html wordwrap-05.html
 fails == overflowwrap-05.html overflowwrap-05.html
-fails == wordwrap-06.html wordwrap-06.html
-fails == overflowwrap-06.html overflowwrap-06.html
+== wordwrap-06.html wordwrap-06.html
+== overflowwrap-06.html overflowwrap-06.html
 == wordwrap-07.html wordwrap-07.html
 == overflowwrap-07.html overflowwrap-07.html
 fails == wordwrap-08.html wordwrap-08.html # Bug 1341637, bug 1321769?
--- a/layout/reftests/transform-3d/reftest-stylo.list
+++ b/layout/reftests/transform-3d/reftest-stylo.list
@ -39,7 +39,7 @@ fails == backface-visibility-1b.html backface-visibility-1b.html
 fails == backface-visibility-1c.html backface-visibility-1c.html
 fails == backface-visibility-2.html backface-visibility-2.html
 == backface-visibility-3.html backface-visibility-3.html
-fails == perspective-clipping-1.html perspective-clipping-1.html
+== perspective-clipping-1.html perspective-clipping-1.html
 fails == perspective-origin-1a.html perspective-origin-1a.html
 fails == perspective-origin-1b.html perspective-origin-1b.html
 fails == perspective-origin-2a.html perspective-origin-2a.html
--- a/layout/reftests/w3c-css/received/reftest-stylo.list
+++ b/layout/reftests/w3c-css/received/reftest-stylo.list
@ -226,18 +226,18 @@ fails == css-values-3/calc-in-media-queries-002.html css-values-3/calc-in-media-
 == css-values-3/calc-parenthesis-stack.html css-values-3/calc-parenthesis-stack.html
 fails == css-values-3/ch-unit-001.html css-values-3/ch-unit-001.html
 == css-values-3/initial-background-color.html css-values-3/initial-background-color.html
-fails == css-values-3/vh-calc-support-pct.html css-values-3/vh-calc-support-pct.html
-fails == css-values-3/vh-calc-support.html css-values-3/vh-calc-support.html
-fails == css-values-3/vh-em-inherit.html css-values-3/vh-em-inherit.html
-fails == css-values-3/vh-inherit.html css-values-3/vh-inherit.html
-fails == css-values-3/vh-interpolate-pct.html css-values-3/vh-interpolate-pct.html
-fails == css-values-3/vh-interpolate-px.html css-values-3/vh-interpolate-px.html
-fails == css-values-3/vh-interpolate-vh.html css-values-3/vh-interpolate-vh.html
+== css-values-3/vh-calc-support-pct.html css-values-3/vh-calc-support-pct.html
+== css-values-3/vh-calc-support.html css-values-3/vh-calc-support.html
+== css-values-3/vh-em-inherit.html css-values-3/vh-em-inherit.html
+== css-values-3/vh-inherit.html css-values-3/vh-inherit.html
+== css-values-3/vh-interpolate-pct.html css-values-3/vh-interpolate-pct.html
+== css-values-3/vh-interpolate-px.html css-values-3/vh-interpolate-px.html
+== css-values-3/vh-interpolate-vh.html css-values-3/vh-interpolate-vh.html
 fails == css-values-3/vh-support-atviewport.html css-values-3/vh-support-atviewport.html
 == css-values-3/vh-support-margin.html css-values-3/vh-support-margin.html
 == css-values-3/vh-support-transform-origin.html css-values-3/vh-support-transform-origin.html
 == css-values-3/vh-support-transform-translate.html css-values-3/vh-support-transform-translate.html
-fails == css-values-3/vh-support.html css-values-3/vh-support.html
+== css-values-3/vh-support.html css-values-3/vh-support.html
 == css-values-3/vh-zero-support.html css-values-3/vh-zero-support.html
 fails == css-values-3/vh_not_refreshing_on_chrome.html css-values-3/vh_not_refreshing_on_chrome.html
 skip-if(stylo) == css-values-3/vh_not_refreshing_on_chrome_iframe.html css-values-3/vh_not_refreshing_on_chrome_iframe.html # Why does this fail to load?
--- a/layout/reftests/w3c-css/submitted/transforms/perspective-zero-2.html
+++ b/layout/reftests/w3c-css/submitted/transforms/perspective-zero-2.html
@ -5,6 +5,7 @@
 <title>CSS transforms: perspective: 0px</title>
 <link rel="author" title="Miko Mynttinen" href="mailto:mmynttinen@mozilla.com">
 <link rel="author" title="Mozilla" href="https://www.mozilla.org">
+<link rel="help" href="https://drafts.csswg.org/css-transforms-2/#propdef-perspective">
 <link rel="help" href="https://github.com/w3c/csswg-drafts/issues/413">
 <meta name="assert" content="Test checks that perspective: 0px behaves like transform: perspective(0) on parent container">
 <link rel="match" href="perspective-zero-2-ref.html">
--- a/layout/reftests/writing-mode/reftest-stylo.list
+++ b/layout/reftests/writing-mode/reftest-stylo.list
@ -147,7 +147,7 @@ skip-if(stylo) == 1172774-percent-padding-1.html 1172774-percent-padding-1.html
 skip-if(stylo) == 1172774-percent-padding-2.html 1172774-percent-padding-2.html
 skip-if(stylo) == 1172774-percent-padding-3.html 1172774-percent-padding-3.html
 skip-if(stylo) == 1172774-percent-padding-4.html 1172774-percent-padding-4.html
-fails == 1174450-intrinsic-sizing.html 1174450-intrinsic-sizing.html
+== 1174450-intrinsic-sizing.html 1174450-intrinsic-sizing.html
 fails == 1175789-underline-overline-1.html 1175789-underline-overline-1.html
 == 1188061-1-nsChangeHint_ClearAncestorIntrinsics.html 1188061-1-nsChangeHint_ClearAncestorIntrinsics.html
 == 1188061-2-nsChangeHint_UpdateComputedBSize.html 1188061-2-nsChangeHint_UpdateComputedBSize.html
--- a/layout/style/CSSMediaRule.cpp
+++ b/layout/style/CSSMediaRule.cpp
@ -0,0 +1,72 @@
+/* -*- 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 http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/dom/CSSMediaRule.h"
+
+#include "mozilla/dom/CSSMediaRuleBinding.h"
+#include "mozilla/dom/MediaList.h"
+
+namespace mozilla {
+namespace dom {
+
+NS_IMPL_ADDREF_INHERITED(CSSMediaRule, css::ConditionRule)
+NS_IMPL_RELEASE_INHERITED(CSSMediaRule, css::ConditionRule)
+
+// QueryInterface implementation for CSSMediaRule
+NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION_INHERITED(CSSMediaRule)
+  NS_INTERFACE_MAP_ENTRY(nsIDOMCSSGroupingRule)
+  NS_INTERFACE_MAP_ENTRY(nsIDOMCSSConditionRule)
+  NS_INTERFACE_MAP_ENTRY(nsIDOMCSSMediaRule)
+NS_INTERFACE_MAP_END_INHERITING(css::ConditionRule)
+
+// nsIDOMCSSGroupingRule methods
+NS_IMETHODIMP
+CSSMediaRule::GetCssRules(nsIDOMCSSRuleList** aRuleList)
+{
+  return GroupRule::GetCssRules(aRuleList);
+}
+
+NS_IMETHODIMP
+CSSMediaRule::InsertRule(const nsAString& aRule,
+                         uint32_t aIndex, uint32_t* _retval)
+{
+  return GroupRule::InsertRule(aRule, aIndex, _retval);
+}
+
+NS_IMETHODIMP
+CSSMediaRule::DeleteRule(uint32_t aIndex)
+{
+  return GroupRule::DeleteRule(aIndex);
+}
+
+// nsIDOMCSSMediaRule methods
+NS_IMETHODIMP
+CSSMediaRule::GetMedia(nsIDOMMediaList* *aMedia)
+{
+  NS_ENSURE_ARG_POINTER(aMedia);
+  NS_IF_ADDREF(*aMedia = Media());
+  return NS_OK;
+}
+
+void
+CSSMediaRule::SetConditionText(const nsAString& aConditionText,
+                               ErrorResult& aRv)
+{
+  nsresult rv = static_cast<nsIDOMCSSConditionRule*>(this)->
+    SetConditionText(aConditionText);
+  if (NS_FAILED(rv)) {
+    aRv.Throw(rv);
+  }
+}
+
+/* virtual */ JSObject*
+CSSMediaRule::WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto)
+{
+  return CSSMediaRuleBinding::Wrap(aCx, this, aGivenProto);
+}
+
+} // namespace dom
+} // namespace mozilla
--- a/layout/style/CSSMediaRule.h
+++ b/layout/style/CSSMediaRule.h
@ -0,0 +1,54 @@
+/* -*- 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 http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_dom_CSSMediaRule_h
+#define mozilla_dom_CSSMediaRule_h
+
+#include "mozilla/css/GroupRule.h"
+#include "nsIDOMCSSMediaRule.h"
+
+namespace mozilla {
+namespace dom {
+
+class CSSMediaRule : public css::ConditionRule
+                   , public nsIDOMCSSMediaRule
+{
+protected:
+  using ConditionRule::ConditionRule;
+  virtual ~CSSMediaRule() {}
+
+public:
+  NS_DECL_ISUPPORTS_INHERITED
+
+  int32_t GetType() const override { return css::Rule::MEDIA_RULE; }
+
+  // XPCOM interface
+  using Rule::GetType;
+
+  // nsIDOMCSSGroupingRule interface
+  NS_DECL_NSIDOMCSSGROUPINGRULE
+
+  // nsIDOMCSSConditionRule interface
+  NS_IMETHOD SetConditionText(const nsAString& aConditionText) override = 0;
+
+  // nsIDOMCSSMediaRule interface
+  NS_DECL_NSIDOMCSSMEDIARULE
+
+  // WebIDL interface
+  uint16_t Type() const override { return nsIDOMCSSRule::MEDIA_RULE; }
+  // Our XPCOM GetConditionText is OK
+  void SetConditionText(const nsAString& aConditionText,
+                        ErrorResult& aRv) final;
+  virtual MediaList* Media() = 0;
+
+  JSObject* WrapObject(JSContext* aCx,
+                       JS::Handle<JSObject*> aGivenProto) override;
+};
+
+} // namespace dom
+} // namespace mozilla
+
+#endif // mozilla_dom_CSSMediaRule_h
--- a/layout/style/CSSStyleSheet.cpp
+++ b/layout/style/CSSStyleSheet.cpp
@ -513,7 +513,8 @@ CSSStyleSheet::UseForPresentation(nsPresContext* aPresContext,
                                  nsMediaQueryResultCacheKey& aKey) const
 {
  if (mMedia) {
-    return mMedia->Matches(aPresContext, &aKey);
+    auto media = static_cast<nsMediaList*>(mMedia.get());
+    return media->Matches(aPresContext, &aKey);
  }
  return true;
 }
@ -900,48 +901,10 @@ CSSStyleSheet::DeleteRuleInternal(uint32_t aIndex, ErrorResult& aRv)
 }

 nsresult
-CSSStyleSheet::DeleteRuleFromGroup(css::GroupRule* aGroup, uint32_t aIndex)
+CSSStyleSheet::InsertRuleIntoGroupInternal(const nsAString& aRule,
+                                           css::GroupRule* aGroup,
+                                           uint32_t aIndex)
 {
-  NS_ENSURE_ARG_POINTER(aGroup);
-  NS_ASSERTION(mInner->mComplete, "No deleting from an incomplete sheet!");
-  RefPtr<css::Rule> rule = aGroup->GetStyleRuleAt(aIndex);
-  NS_ENSURE_TRUE(rule, NS_ERROR_ILLEGAL_VALUE);
-
-  // check that the rule actually belongs to this sheet!
-  if (this != rule->GetStyleSheet()) {
-    return NS_ERROR_INVALID_ARG;
-  }
-
-  mozAutoDocUpdate updateBatch(mDocument, UPDATE_STYLE, true);
-  
-  WillDirty();
-
-  nsresult result = aGroup->DeleteStyleRuleAt(aIndex);
-  NS_ENSURE_SUCCESS(result, result);
-  
-  rule->SetStyleSheet(nullptr);
-  
-  DidDirty();
-
-  if (mDocument) {
-    mDocument->StyleRuleRemoved(this, rule);
-  }
-
-  return NS_OK;
-}
-
-nsresult
-CSSStyleSheet::InsertRuleIntoGroup(const nsAString & aRule,
-                                   css::GroupRule* aGroup,
-                                   uint32_t aIndex,
-                                   uint32_t* _retval)
-{
-  NS_ASSERTION(mInner->mComplete, "No inserting into an incomplete sheet!");
-  // check that the group actually belongs to this sheet!
-  if (this != aGroup->GetStyleSheet()) {
-    return NS_ERROR_INVALID_ARG;
-  }
-
  // Hold strong ref to the CSSLoader in case the document update
  // kills the document
  RefPtr<css::Loader> loader;
@ -952,11 +915,6 @@ CSSStyleSheet::InsertRuleIntoGroup(const nsAString & aRule,

  nsCSSParser css(loader, this);

-  // parse and grab the rule
-  mozAutoDocUpdate updateBatch(mDocument, UPDATE_STYLE, true);
-
-  WillDirty();
-
  RefPtr<css::Rule> rule;
  nsresult result = css.ParseRule(aRule, mInner->mSheetURI, mInner->mBaseURI,
                                  mInner->mPrincipal, getter_AddRefs(rule));
@ -984,16 +942,7 @@ CSSStyleSheet::InsertRuleIntoGroup(const nsAString & aRule,
      return NS_ERROR_DOM_HIERARCHY_REQUEST_ERR;
  }

-  result = aGroup->InsertStyleRuleAt(aIndex, rule);
-  NS_ENSURE_SUCCESS(result, result);
-  DidDirty();
-
-  if (mDocument) {
-    mDocument->StyleRuleAdded(this, rule);
-  }
-
-  *_retval = aIndex;
-  return NS_OK;
+  return aGroup->InsertStyleRuleAt(aIndex, rule);
 }

 // nsICSSLoaderObserver implementation
--- a/layout/style/CSSStyleSheet.h
+++ b/layout/style/CSSStyleSheet.h
@ -116,9 +116,6 @@ public:
  int32_t StyleRuleCount() const;
  css::Rule* GetStyleRuleAt(int32_t aIndex) const;

-  nsresult DeleteRuleFromGroup(css::GroupRule* aGroup, uint32_t aIndex);
-  nsresult InsertRuleIntoGroup(const nsAString& aRule, css::GroupRule* aGroup, uint32_t aIndex, uint32_t* _retval);
-
  void SetOwnerRule(css::ImportRule* aOwnerRule) { mOwnerRule = aOwnerRule; /* Not ref counted */ }
  css::ImportRule* GetOwnerRule() const { return mOwnerRule; }
  // Workaround overloaded-virtual warning in GCC.
@ -222,6 +219,9 @@ protected:
  uint32_t InsertRuleInternal(const nsAString& aRule,
                              uint32_t aIndex, ErrorResult& aRv);
  void DeleteRuleInternal(uint32_t aIndex, ErrorResult& aRv);
+  nsresult InsertRuleIntoGroupInternal(const nsAString& aRule,
+                                       css::GroupRule* aGroup,
+                                       uint32_t aIndex);

  void EnabledStateChangedInternal();

--- a/layout/style/GroupRule.cpp
+++ b/layout/style/GroupRule.cpp
@ -0,0 +1,420 @@
+/* -*- 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 http://mozilla.org/MPL/2.0/. */
+
+/*
+ * internal interface representing CSS style rules that contain other
+ * rules, such as @media rules
+ */
+
+#include "mozilla/css/GroupRule.h"
+
+#include "mozilla/dom/CSSRuleList.h"
+
+using namespace mozilla::dom;
+
+namespace mozilla {
+namespace css {
+
+#define CALL_INNER(inner_, call_)               \
+  ((inner_).is<GeckoGroupRuleRules>()           \
+    ? (inner_).as<GeckoGroupRuleRules>().call_  \
+    : (inner_).as<ServoGroupRuleRules>().call_)
+
+// -------------------------------
+// Style Rule List for group rules
+//
+
+class GroupRuleRuleList final : public dom::CSSRuleList
+{
+public:
+  explicit GroupRuleRuleList(GroupRule *aGroupRule);
+
+  virtual CSSStyleSheet* GetParentObject() override;
+
+  virtual Rule*
+  IndexedGetter(uint32_t aIndex, bool& aFound) override;
+  virtual uint32_t
+  Length() override;
+
+  void DropReference() { mGroupRule = nullptr; }
+
+private:
+  ~GroupRuleRuleList();
+
+private:
+  GroupRule* mGroupRule;
+};
+
+GroupRuleRuleList::GroupRuleRuleList(GroupRule *aGroupRule)
+{
+  // Not reference counted to avoid circular references.
+  // The rule will tell us when its going away.
+  mGroupRule = aGroupRule;
+}
+
+GroupRuleRuleList::~GroupRuleRuleList()
+{
+}
+
+CSSStyleSheet*
+GroupRuleRuleList::GetParentObject()
+{
+  if (!mGroupRule) {
+    return nullptr;
+  }
+  StyleSheet* sheet = mGroupRule->GetStyleSheet();
+  return sheet ? sheet->AsGecko() : nullptr;
+}
+
+uint32_t
+GroupRuleRuleList::Length()
+{
+  if (!mGroupRule) {
+    return 0;
+  }
+
+  return AssertedCast<uint32_t>(mGroupRule->StyleRuleCount());
+}
+
+Rule*
+GroupRuleRuleList::IndexedGetter(uint32_t aIndex, bool& aFound)
+{
+  aFound = false;
+
+  if (mGroupRule) {
+    RefPtr<Rule> rule = mGroupRule->GetStyleRuleAt(aIndex);
+    if (rule) {
+      aFound = true;
+      return rule;
+    }
+  }
+
+  return nullptr;
+}
+
+// -------------------------------
+// GeckoGroupRuleRules
+//
+
+GeckoGroupRuleRules::GeckoGroupRuleRules()
+{
+}
+
+GeckoGroupRuleRules::GeckoGroupRuleRules(GeckoGroupRuleRules&& aOther)
+  : mRules(Move(aOther.mRules))
+  , mRuleCollection(Move(aOther.mRuleCollection))
+{
+}
+
+GeckoGroupRuleRules::GeckoGroupRuleRules(const GeckoGroupRuleRules& aCopy)
+{
+  for (const Rule* rule : aCopy.mRules) {
+    RefPtr<Rule> clone = rule->Clone();
+    mRules.AppendObject(clone);
+  }
+}
+
+GeckoGroupRuleRules::~GeckoGroupRuleRules()
+{
+  for (Rule* rule : mRules) {
+    rule->SetParentRule(nullptr);
+  }
+  if (mRuleCollection) {
+    mRuleCollection->DropReference();
+  }
+}
+
+void
+GeckoGroupRuleRules::Clear()
+{
+  mRules.Clear();
+  if (mRuleCollection) {
+    mRuleCollection->DropReference();
+    mRuleCollection = nullptr;
+  }
+}
+
+void
+GeckoGroupRuleRules::Traverse(nsCycleCollectionTraversalCallback& cb)
+{
+  IncrementalClearCOMRuleArray& rules = mRules;
+  for (int32_t i = 0, count = rules.Count(); i < count; ++i) {
+    if (!rules[i]->IsCCLeaf()) {
+      NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(cb, "mRules[i]");
+      cb.NoteXPCOMChild(rules[i]);
+    }
+  }
+  ImplCycleCollectionTraverse(cb, mRuleCollection, "mRuleCollection");
+}
+
+#ifdef DEBUG
+void
+GeckoGroupRuleRules::List(FILE* out, int32_t aIndent) const
+{
+  for (const Rule* rule : mRules) {
+    rule->List(out, aIndent + 1);
+  }
+}
+#endif
+
+nsresult
+GeckoGroupRuleRules::DeleteStyleRuleAt(uint32_t aIndex)
+{
+  Rule* rule = mRules.SafeObjectAt(aIndex);
+  if (rule) {
+    rule->SetStyleSheet(nullptr);
+    rule->SetParentRule(nullptr);
+  }
+  return mRules.RemoveObjectAt(aIndex) ? NS_OK : NS_ERROR_ILLEGAL_VALUE;
+}
+
+CSSRuleList*
+GeckoGroupRuleRules::CssRules(GroupRule* aParentRule)
+{
+  if (!mRuleCollection) {
+    mRuleCollection = new GroupRuleRuleList(aParentRule);
+  }
+  return mRuleCollection;
+}
+
+size_t
+GeckoGroupRuleRules::SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const
+{
+  size_t n = mRules.ShallowSizeOfExcludingThis(aMallocSizeOf);
+  for (const Rule* rule : mRules) {
+    n += rule->SizeOfIncludingThis(aMallocSizeOf);
+  }
+
+  // Measurement of the following members may be added later if DMD finds it is
+  // worthwhile:
+  // - mRuleCollection
+  return n;
+}
+
+// -------------------------------
+// ServoGroupRuleRules
+//
+
+#ifdef DEBUG
+void
+ServoGroupRuleRules::List(FILE* out, int32_t aIndent) const
+{
+  // TODO list something reasonable?
+}
+#endif
+
+size_t
+ServoGroupRuleRules::SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const
+{
+  // TODO how to implement?
+  return 0;
+}
+
+// -------------------------------
+// GroupRule
+//
+
+GroupRule::GroupRule(uint32_t aLineNumber, uint32_t aColumnNumber)
+  : Rule(aLineNumber, aColumnNumber)
+  , mInner(GeckoGroupRuleRules())
+{
+}
+
+GroupRule::GroupRule(already_AddRefed<ServoCssRules> aRules)
+  : Rule(0, 0) // TODO
+  , mInner(ServoGroupRuleRules(Move(aRules)))
+{
+  mInner.as<ServoGroupRuleRules>().SetParentRule(this);
+}
+
+GroupRule::GroupRule(const GroupRule& aCopy)
+  : Rule(aCopy)
+  , mInner(aCopy.mInner)
+{
+  CALL_INNER(mInner, SetParentRule(this));
+}
+
+GroupRule::~GroupRule()
+{
+  MOZ_ASSERT(!mSheet, "SetStyleSheet should have been called");
+}
+
+NS_IMPL_ADDREF_INHERITED(GroupRule, Rule)
+NS_IMPL_RELEASE_INHERITED(GroupRule, Rule)
+
+NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION_INHERITED(GroupRule)
+NS_INTERFACE_MAP_END_INHERITING(Rule)
+
+bool
+GroupRule::IsCCLeaf() const
+{
+  // Let's not worry for now about sorting out whether we're a leaf or not.
+  return false;
+}
+
+NS_IMPL_CYCLE_COLLECTION_CLASS(GroupRule)
+
+NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN_INHERITED(GroupRule, Rule)
+  CALL_INNER(tmp->mInner, SetParentRule(nullptr));
+  // If tmp does not have a stylesheet, neither do its descendants.  In that
+  // case, don't try to null out their stylesheet, to avoid O(N^2) behavior in
+  // depth of group rule nesting.  But if tmp _does_ have a stylesheet (which
+  // can happen if it gets unlinked earlier than its owning stylesheet), then we
+  // need to null out the stylesheet pointer on descendants now, before we clear
+  // tmp->mRules.
+  if (tmp->GetStyleSheet()) {
+    CALL_INNER(tmp->mInner, SetStyleSheet(nullptr));
+  }
+  CALL_INNER(tmp->mInner, Clear());
+NS_IMPL_CYCLE_COLLECTION_UNLINK_END
+
+NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN_INHERITED(GroupRule, Rule)
+  CALL_INNER(tmp->mInner, Traverse(cb));
+NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
+
+/* virtual */ void
+GroupRule::SetStyleSheet(StyleSheet* aSheet)
+{
+  // Don't set the sheet on the kids if it's already the same as the sheet we
+  // already have.  This is needed to avoid O(N^2) behavior in group nesting
+  // depth when seting the sheet to null during unlink, if we happen to unlin in
+  // order from most nested rule up to least nested rule.
+  if (aSheet != GetStyleSheet()) {
+    CALL_INNER(mInner, SetStyleSheet(aSheet));
+    Rule::SetStyleSheet(aSheet);
+  }
+}
+
+void
+GroupRule::AppendStyleRule(Rule* aRule)
+{
+  GeckoRules().AppendObject(aRule);
+  StyleSheet* sheet = GetStyleSheet();
+  aRule->SetStyleSheet(sheet);
+  aRule->SetParentRule(this);
+  if (sheet) {
+    sheet->AsGecko()->SetModifiedByChildRule();
+  }
+}
+
+bool
+GroupRule::EnumerateRulesForwards(RuleEnumFunc aFunc, void * aData) const
+{
+  for (const Rule* rule : GeckoRules()) {
+    if (!aFunc(const_cast<Rule*>(rule), aData)) {
+      return false;
+    }
+  }
+  return true;
+}
+
+nsresult
+GroupRule::InsertStyleRuleAt(uint32_t aIndex, Rule* aRule)
+{
+  aRule->SetStyleSheet(GetStyleSheet());
+  aRule->SetParentRule(this);
+  if (!GeckoRules().InsertObjectAt(aRule, aIndex)) {
+    return NS_ERROR_FAILURE;
+  }
+  return NS_OK;
+}
+
+void
+GroupRule::AppendRulesToCssText(nsAString& aCssText) const
+{
+  aCssText.AppendLiteral(" {\n");
+  for (const Rule* rule : GeckoRules()) {
+    nsAutoString cssText;
+    rule->GetCssText(cssText);
+    aCssText.AppendLiteral("  ");
+    aCssText.Append(cssText);
+    aCssText.Append('\n');
+  }
+  aCssText.Append('}');
+}
+
+// nsIDOMCSSMediaRule or nsIDOMCSSMozDocumentRule methods
+nsresult
+GroupRule::GetCssRules(nsIDOMCSSRuleList* *aRuleList)
+{
+  NS_ADDREF(*aRuleList = CssRules());
+  return NS_OK;
+}
+
+CSSRuleList*
+GroupRule::CssRules()
+{
+  return CALL_INNER(mInner, CssRules(this));
+}
+
+nsresult
+GroupRule::InsertRule(const nsAString & aRule, uint32_t aIndex, uint32_t* _retval)
+{
+  ErrorResult rv;
+  *_retval = InsertRule(aRule, aIndex, rv);
+  return rv.StealNSResult();
+}
+
+uint32_t
+GroupRule::InsertRule(const nsAString& aRule, uint32_t aIndex, ErrorResult& aRv)
+{
+  StyleSheet* sheet = GetStyleSheet();
+  if (NS_WARN_IF(!sheet)) {
+    aRv.Throw(NS_ERROR_FAILURE);
+    return 0;
+  }
+
+  uint32_t count = StyleRuleCount();
+  if (aIndex > count) {
+    aRv.Throw(NS_ERROR_DOM_INDEX_SIZE_ERR);
+    return 0;
+  }
+
+  NS_ASSERTION(count <= INT32_MAX, "Too many style rules!");
+
+  nsresult rv = sheet->InsertRuleIntoGroup(aRule, this, aIndex);
+  if (NS_FAILED(rv)) {
+    aRv.Throw(rv);
+    return 0;
+  }
+  return aIndex;
+}
+
+nsresult
+GroupRule::DeleteRule(uint32_t aIndex)
+{
+  ErrorResult rv;
+  DeleteRule(aIndex, rv);
+  return rv.StealNSResult();
+}
+
+void
+GroupRule::DeleteRule(uint32_t aIndex, ErrorResult& aRv)
+{
+  StyleSheet* sheet = GetStyleSheet();
+  if (NS_WARN_IF(!sheet)) {
+    aRv.Throw(NS_ERROR_FAILURE);
+    return;
+  }
+
+  uint32_t count = StyleRuleCount();
+  if (aIndex >= count) {
+    aRv.Throw(NS_ERROR_DOM_INDEX_SIZE_ERR);
+    return;
+  }
+
+  NS_ASSERTION(count <= INT32_MAX, "Too many style rules!");
+
+  nsresult rv = sheet->DeleteRuleFromGroup(this, aIndex);
+  if (NS_FAILED(rv)) {
+    aRv.Throw(rv);
+  }
+}
+
+#undef CALL_INNER
+
+} // namespace css
+} // namespace mozilla
--- a/layout/style/GroupRule.h
+++ b/layout/style/GroupRule.h
@ -15,6 +15,8 @@
 #include "mozilla/ErrorResult.h"
 #include "mozilla/IncrementalClearCOMRuleArray.h"
 #include "mozilla/MemoryReporting.h"
+#include "mozilla/ServoCSSRuleList.h"
+#include "mozilla/Variant.h"
 #include "mozilla/css/Rule.h"
 #include "nsCycleCollectionParticipant.h"

@ -31,14 +33,115 @@ class CSSRuleList;

 namespace css {

+class GroupRule;
 class GroupRuleRuleList;

+struct GeckoGroupRuleRules
+{
+  GeckoGroupRuleRules();
+  GeckoGroupRuleRules(GeckoGroupRuleRules&& aOther);
+  GeckoGroupRuleRules(const GeckoGroupRuleRules& aCopy);
+  ~GeckoGroupRuleRules();
+
+  void SetParentRule(GroupRule* aParentRule) {
+    for (Rule* rule : mRules) {
+      rule->SetParentRule(aParentRule);
+    }
+  }
+  void SetStyleSheet(StyleSheet* aSheet) {
+    for (Rule* rule : mRules) {
+      rule->SetStyleSheet(aSheet);
+    }
+  }
+
+  void Clear();
+  void Traverse(nsCycleCollectionTraversalCallback& cb);
+
+#ifdef DEBUG
+  void List(FILE* out, int32_t aIndent) const;
+#endif
+
+  int32_t StyleRuleCount() const { return mRules.Count(); }
+  Rule* GetStyleRuleAt(int32_t aIndex) const {
+    return mRules.SafeObjectAt(aIndex);
+  }
+
+  nsresult DeleteStyleRuleAt(uint32_t aIndex);
+
+  dom::CSSRuleList* CssRules(GroupRule* aParentRule);
+
+  size_t SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const;
+
+  IncrementalClearCOMRuleArray mRules;
+  RefPtr<GroupRuleRuleList> mRuleCollection; // lazily constructed
+};
+
+struct ServoGroupRuleRules
+{
+  explicit ServoGroupRuleRules(already_AddRefed<ServoCssRules> aRawRules)
+    : mRuleList(new ServoCSSRuleList(Move(aRawRules))) {}
+  ServoGroupRuleRules(ServoGroupRuleRules&& aOther)
+    : mRuleList(Move(aOther.mRuleList)) {}
+  ServoGroupRuleRules(const ServoGroupRuleRules& aCopy) {
+    // Do we ever clone Servo rules?
+    MOZ_ASSERT_UNREACHABLE("stylo: Cloning GroupRule not implemented");
+  }
+
+  void SetParentRule(GroupRule* aParentRule) {
+    if (mRuleList) {
+      mRuleList->SetParentRule(aParentRule);
+    }
+  }
+  void SetStyleSheet(StyleSheet* aSheet) {
+    if (mRuleList) {
+      mRuleList->SetStyleSheet(aSheet);
+    }
+  }
+
+  void Clear() {
+    mRuleList->DropReference();
+    mRuleList = nullptr;
+  }
+  void Traverse(nsCycleCollectionTraversalCallback& cb) {
+    ImplCycleCollectionTraverse(cb, mRuleList, "mRuleList");
+  }
+
+#ifdef DEBUG
+  void List(FILE* out, int32_t aIndent) const;
+#endif
+
+  int32_t StyleRuleCount() const { return mRuleList->Length(); }
+  Rule* GetStyleRuleAt(int32_t aIndex) const {
+    return mRuleList->GetRule(aIndex);
+  }
+
+  nsresult DeleteStyleRuleAt(uint32_t aIndex) {
+    return mRuleList->DeleteRule(aIndex);
+  }
+
+  dom::CSSRuleList* CssRules(GroupRule* aParentRule) {
+    return mRuleList;
+  }
+
+  size_t SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const;
+
+  RefPtr<ServoCSSRuleList> mRuleList;
+};
+
+#define REDIRECT_TO_INNER(call_)                   \
+  if (mInner.is<GeckoGroupRuleRules>()) {          \
+    return mInner.as<GeckoGroupRuleRules>().call_; \
+  } else {                                         \
+    return mInner.as<ServoGroupRuleRules>().call_; \
+  }                                                \
+
 // inherits from Rule so it can be shared between
 // MediaRule and DocumentRule
 class GroupRule : public Rule
 {
 protected:
  GroupRule(uint32_t aLineNumber, uint32_t aColumnNumber);
+  explicit GroupRule(already_AddRefed<ServoCssRules> aRules);
  GroupRule(const GroupRule& aCopy);
  virtual ~GroupRule();
 public:
@ -48,32 +151,42 @@ public:
  virtual bool IsCCLeaf() const override;

 #ifdef DEBUG
-  virtual void List(FILE* out = stdout, int32_t aIndent = 0) const override;
+  void List(FILE* out = stdout, int32_t aIndent = 0) const override {
+    REDIRECT_TO_INNER(List(out, aIndent))
+  }
 #endif
  virtual void SetStyleSheet(StyleSheet* aSheet) override;

 public:
  void AppendStyleRule(Rule* aRule);

-  int32_t StyleRuleCount() const { return mRules.Count(); }
-  Rule* GetStyleRuleAt(int32_t aIndex) const;
+  int32_t StyleRuleCount() const {
+    REDIRECT_TO_INNER(StyleRuleCount())
+  }
+  Rule* GetStyleRuleAt(uint32_t aIndex) const {
+    REDIRECT_TO_INNER(GetStyleRuleAt(aIndex))
+  }

  typedef bool (*RuleEnumFunc)(Rule* aElement, void* aData);
  bool EnumerateRulesForwards(RuleEnumFunc aFunc, void * aData) const;

  /*
-   * The next three methods should never be called unless you have first
+   * The next two methods should never be called unless you have first
   * called WillDirty() on the parent stylesheet.  After they are
   * called, DidDirty() needs to be called on the sheet.
   */
-  nsresult DeleteStyleRuleAt(uint32_t aIndex);
+  nsresult DeleteStyleRuleAt(uint32_t aIndex) {
+    REDIRECT_TO_INNER(DeleteStyleRuleAt(aIndex));
+  }
  nsresult InsertStyleRuleAt(uint32_t aIndex, Rule* aRule);

  virtual bool UseForPresentation(nsPresContext* aPresContext,
                                    nsMediaQueryResultCacheKey& aKey) = 0;

  // non-virtual -- it is only called by subclasses
-  size_t SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const;
+  size_t SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const {
+    REDIRECT_TO_INNER(SizeOfExcludingThis(aMallocSizeOf))
+  }
  virtual size_t SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const override = 0;

  // WebIDL API
@ -93,20 +206,27 @@ protected:
                      uint32_t* _retval);
  nsresult DeleteRule(uint32_t aIndex);

-  IncrementalClearCOMRuleArray mRules;
-  RefPtr<GroupRuleRuleList> mRuleCollection; // lazily constructed
+  // Must only be called if this is a Gecko GroupRule.
+  IncrementalClearCOMRuleArray& GeckoRules() {
+    return mInner.as<GeckoGroupRuleRules>().mRules;
+  }
+  const IncrementalClearCOMRuleArray& GeckoRules() const {
+    return mInner.as<GeckoGroupRuleRules>().mRules;
+  }
+
+private:
+  Variant<GeckoGroupRuleRules, ServoGroupRuleRules> mInner;
 };

+#undef REDIRECT_TO_INNER
+
 // Implementation of WebIDL CSSConditionRule.
 class ConditionRule : public GroupRule
 {
 protected:
-  ConditionRule(uint32_t aLineNumber, uint32_t aColumnNumber);
-  ConditionRule(const ConditionRule& aCopy);
-  virtual ~ConditionRule();
+  using GroupRule::GroupRule;

 public:
-
  // GetConditionText signature matches nsIDOMCSSConditionRule, so subclasses
  // can implement this easily.  The implementations should never return
  // anything other than NS_OK.
--- a/layout/style/ImportRule.h
+++ b/layout/style/ImportRule.h
@ -22,6 +22,10 @@ namespace mozilla {
 class CSSStyleSheet;
 class StyleSheet;

+namespace dom {
+class MediaList;
+}
+
 namespace css {

 class ImportRule final : public Rule,
@ -63,7 +67,7 @@ public:
  uint16_t Type() const override;
  void GetCssTextImpl(nsAString& aCssText) const override;
  // The XPCOM GetHref is fine, since it never fails.
-  nsMediaList* Media() const { return mMedia; }
+  dom::MediaList* Media() const;
  StyleSheet* GetStyleSheet() const;

 private:
--- a/layout/style/MediaList.cpp
+++ b/layout/style/MediaList.cpp
@ -0,0 +1,117 @@
+/* -*- 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 http://mozilla.org/MPL/2.0/. */
+
+/* base class for representation of media lists */
+
+#include "mozilla/dom/MediaList.h"
+
+#include "mozAutoDocUpdate.h"
+#include "mozilla/dom/MediaListBinding.h"
+#include "mozilla/StyleSheetInlines.h"
+
+namespace mozilla {
+namespace dom {
+
+NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(MediaList)
+  NS_WRAPPERCACHE_INTERFACE_MAP_ENTRY
+  NS_INTERFACE_MAP_ENTRY(nsIDOMMediaList)
+  NS_INTERFACE_MAP_ENTRY(nsISupports)
+NS_INTERFACE_MAP_END
+
+NS_IMPL_CYCLE_COLLECTING_ADDREF(MediaList)
+NS_IMPL_CYCLE_COLLECTING_RELEASE(MediaList)
+
+NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE_0(MediaList)
+
+JSObject*
+MediaList::WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto)
+{
+  return MediaListBinding::Wrap(aCx, this, aGivenProto);
+}
+
+void
+MediaList::SetStyleSheet(StyleSheet* aSheet)
+{
+  MOZ_ASSERT(aSheet == mStyleSheet || !aSheet || !mStyleSheet,
+             "Multiple style sheets competing for one media list");
+  mStyleSheet = aSheet;
+}
+
+template<typename Func>
+nsresult
+MediaList::DoMediaChange(Func aCallback)
+{
+  nsCOMPtr<nsIDocument> doc;
+  if (mStyleSheet) {
+    doc = mStyleSheet->GetAssociatedDocument();
+  }
+  mozAutoDocUpdate updateBatch(doc, UPDATE_STYLE, true);
+  if (mStyleSheet) {
+    mStyleSheet->WillDirty();
+  }
+
+  nsresult rv = aCallback();
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  if (mStyleSheet) {
+    mStyleSheet->DidDirty();
+  }
+  /* XXXldb Pass something meaningful? */
+  if (doc) {
+    doc->StyleRuleChanged(mStyleSheet, nullptr);
+  }
+  return rv;
+}
+
+NS_IMETHODIMP
+MediaList::GetMediaText(nsAString& aMediaText)
+{
+  GetText(aMediaText);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+MediaList::SetMediaText(const nsAString& aMediaText)
+{
+  return DoMediaChange([&]() {
+    SetText(aMediaText);
+    return NS_OK;
+  });
+}
+
+NS_IMETHODIMP
+MediaList::GetLength(uint32_t* aLength)
+{
+  NS_ENSURE_ARG_POINTER(aLength);
+
+  *aLength = Length();
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+MediaList::Item(uint32_t aIndex, nsAString& aReturn)
+{
+  bool dummy;
+  IndexedGetter(aIndex, dummy, aReturn);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+MediaList::DeleteMedium(const nsAString& aOldMedium)
+{
+  return DoMediaChange([&]() { return Delete(aOldMedium); });
+}
+
+NS_IMETHODIMP
+MediaList::AppendMedium(const nsAString& aNewMedium)
+{
+  return DoMediaChange([&]() { return Append(aNewMedium); });
+}
+
+} // namespace dom
+} // namespace mozilla
--- a/layout/style/MediaList.h
+++ b/layout/style/MediaList.h
@ -0,0 +1,84 @@
+/* -*- 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 http://mozilla.org/MPL/2.0/. */
+
+/* base class for representation of media lists */
+
+#ifndef mozilla_dom_MediaList_h
+#define mozilla_dom_MediaList_h
+
+#include "mozilla/ErrorResult.h"
+#include "mozilla/ServoUtils.h"
+
+#include "nsIDOMMediaList.h"
+#include "nsWrapperCache.h"
+
+namespace mozilla {
+class StyleSheet;
+
+namespace dom {
+
+// XXX This class doesn't use the branch dispatch approach that we use
+//     elsewhere for stylo, but instead just relies on virtual call.
+//     That's because this class should not be critical to performance,
+//     and using branch dispatch would make it much more complicated.
+//     Performance critical path should hold a subclass of this class
+//     directly. We may want to determine in the future whether the
+//     above is correct.
+
+class MediaList : public nsIDOMMediaList
+                , public nsWrapperCache
+{
+public:
+  NS_DECL_CYCLE_COLLECTING_ISUPPORTS
+  NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS(MediaList)
+
+  virtual already_AddRefed<MediaList> Clone() = 0;
+
+  JSObject* WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto) final;
+  nsISupports* GetParentObject() const { return nullptr; }
+
+  virtual void GetText(nsAString& aMediaText) = 0;
+  virtual void SetText(const nsAString& aMediaText) = 0;
+
+  void SetStyleSheet(StyleSheet* aSheet);
+
+  NS_DECL_NSIDOMMEDIALIST
+
+  // WebIDL
+  // XPCOM GetMediaText and SetMediaText are fine.
+  virtual uint32_t Length() = 0;
+  virtual void IndexedGetter(uint32_t aIndex, bool& aFound,
+                             nsAString& aReturn) = 0;
+  // XPCOM Item is fine.
+  void DeleteMedium(const nsAString& aMedium, ErrorResult& aRv)
+  {
+    aRv = DeleteMedium(aMedium);
+  }
+  void AppendMedium(const nsAString& aMedium, ErrorResult& aRv)
+  {
+    aRv = AppendMedium(aMedium);
+  }
+
+protected:
+  virtual nsresult Delete(const nsAString& aOldMedium) = 0;
+  virtual nsresult Append(const nsAString& aNewMedium) = 0;
+
+  virtual ~MediaList() {}
+
+  // not refcounted; sheet will let us know when it goes away
+  // mStyleSheet is the sheet that needs to be dirtied when this
+  // medialist changes
+  StyleSheet* mStyleSheet = nullptr;
+
+private:
+  template<typename Func>
+  inline nsresult DoMediaChange(Func aCallback);
+};
+
+} // namespace dom
+} // namespace mozilla
+
+#endif // mozilla_dom_MediaList_h
--- a/layout/style/Rule.h
+++ b/layout/style/Rule.h
@ -118,7 +118,7 @@ public:
  // WebIDL interface, aka helpers for nsIDOMCSSRule implementation.
  virtual uint16_t Type() const = 0;
  virtual void GetCssTextImpl(nsAString& aCssText) const = 0;
-  // XPCOM GetCssText is OK, since it never throws.
+  void GetCssText(nsAString& aCssText) const { GetCssTextImpl(aCssText); }
  // XPCOM SetCssText is OK, since it never throws.
  Rule* GetParentRule() const;
  StyleSheet* GetParentStyleSheet() const { return GetStyleSheet(); }
--- a/layout/style/ServoArcTypeList.h
+++ b/layout/style/ServoArcTypeList.h
@ -13,3 +13,5 @@ SERVO_ARC_TYPE(DeclarationBlock, RawServoDeclarationBlock)
 SERVO_ARC_TYPE(StyleRule, RawServoStyleRule)
 SERVO_ARC_TYPE(ImportRule, RawServoImportRule)
 SERVO_ARC_TYPE(AnimationValue, RawServoAnimationValue)
+SERVO_ARC_TYPE(MediaList, RawServoMediaList)
+SERVO_ARC_TYPE(MediaRule, RawServoMediaRule)
--- a/layout/style/ServoBindingList.h
+++ b/layout/style/ServoBindingList.h
@ -78,6 +78,8 @@ SERVO_BINDING_FUNC(Servo_CssRules_ListTypes, void,
                   nsTArrayBorrowed_uintptr_t result)
 SERVO_BINDING_FUNC(Servo_CssRules_GetStyleRuleAt, RawServoStyleRuleStrong,
                   ServoCssRulesBorrowed rules, uint32_t index)
+SERVO_BINDING_FUNC(Servo_CssRules_GetMediaRuleAt, RawServoMediaRuleStrong,
+                   ServoCssRulesBorrowed rules, uint32_t index)
 SERVO_BINDING_FUNC(Servo_CssRules_InsertRule, nsresult,
                   ServoCssRulesBorrowed rules,
                   RawServoStyleSheetBorrowed sheet, const nsACString* rule,
@ -97,6 +99,14 @@ SERVO_BINDING_FUNC(Servo_StyleRule_GetCssText, void,
                   RawServoStyleRuleBorrowed rule, nsAString* result)
 SERVO_BINDING_FUNC(Servo_StyleRule_GetSelectorText, void,
                   RawServoStyleRuleBorrowed rule, nsAString* result)
+SERVO_BINDING_FUNC(Servo_MediaRule_Debug, void,
+                   RawServoMediaRuleBorrowed rule, nsACString* result)
+SERVO_BINDING_FUNC(Servo_MediaRule_GetMedia, RawServoMediaListStrong,
+                   RawServoMediaRuleBorrowed rule)
+SERVO_BINDING_FUNC(Servo_MediaRule_GetRules, ServoCssRulesStrong,
+                   RawServoMediaRuleBorrowed rule)
+SERVO_BINDING_FUNC(Servo_MediaRule_GetCssText, void,
+                   RawServoMediaRuleBorrowed rule, nsAString* result)

 // Animations API
 SERVO_BINDING_FUNC(Servo_ParseProperty,
@ -108,7 +118,7 @@ SERVO_BINDING_FUNC(Servo_GetComputedKeyframeValues, void,
                   RawGeckoKeyframeListBorrowed keyframes,
                   ServoComputedValuesBorrowed style,
                   ServoComputedValuesBorrowedOrNull parent_style,
-                   RawGeckoPresContextBorrowed pres_context,
+                   RawServoStyleSetBorrowed set,
                   RawGeckoComputedKeyframeValuesListBorrowedMut result)

 // AnimationValues handling
@ -135,7 +145,9 @@ SERVO_BINDING_FUNC(Servo_AnimationValue_DeepEqual, bool,

 // Style attribute
 SERVO_BINDING_FUNC(Servo_ParseStyleAttribute, RawServoDeclarationBlockStrong,
-                   const nsACString* data)
+                   const nsACString* data,
+                   const nsACString* base,
+                   const GeckoParserExtraData* extraData)
 SERVO_BINDING_FUNC(Servo_DeclarationBlock_CreateEmpty,
                   RawServoDeclarationBlockStrong)
 SERVO_BINDING_FUNC(Servo_DeclarationBlock_Clone, RawServoDeclarationBlockStrong,
@ -222,6 +234,21 @@ SERVO_BINDING_FUNC(Servo_DeclarationBlock_SetFontFamily, void,
 SERVO_BINDING_FUNC(Servo_DeclarationBlock_SetTextDecorationColorOverride, void,
                   RawServoDeclarationBlockBorrowed declarations)

+// MediaList
+SERVO_BINDING_FUNC(Servo_MediaList_GetText, void,
+                   RawServoMediaListBorrowed list, nsAString* result)
+SERVO_BINDING_FUNC(Servo_MediaList_SetText, void,
+                   RawServoMediaListBorrowed list, const nsACString* text)
+SERVO_BINDING_FUNC(Servo_MediaList_GetLength, uint32_t,
+                   RawServoMediaListBorrowed list)
+SERVO_BINDING_FUNC(Servo_MediaList_GetMediumAt, bool,
+                   RawServoMediaListBorrowed list, uint32_t index,
+                   nsAString* result)
+SERVO_BINDING_FUNC(Servo_MediaList_AppendMedium, void,
+                   RawServoMediaListBorrowed list, const nsACString* new_medium)
+SERVO_BINDING_FUNC(Servo_MediaList_DeleteMedium, bool,
+                   RawServoMediaListBorrowed list, const nsACString* old_medium)
+
 // CSS supports()
 SERVO_BINDING_FUNC(Servo_CSSSupports2, bool,
                   const nsACString* name, const nsACString* value)
--- a/layout/style/ServoCSSRuleList.cpp
+++ b/layout/style/ServoCSSRuleList.cpp
@ -10,13 +10,12 @@

 #include "mozilla/ServoBindings.h"
 #include "mozilla/ServoStyleRule.h"
+#include "mozilla/ServoMediaRule.h"

 namespace mozilla {

-ServoCSSRuleList::ServoCSSRuleList(ServoStyleSheet* aStyleSheet,
-                                   already_AddRefed<ServoCssRules> aRawRules)
-  : mStyleSheet(aStyleSheet)
-  , mRawRules(aRawRules)
+ServoCSSRuleList::ServoCSSRuleList(already_AddRefed<ServoCssRules> aRawRules)
+  : mRawRules(aRawRules)
 {
  Servo_CssRules_ListTypes(mRawRules, &mRules);
  // XXX We may want to eagerly create object for import rule, so that
@ -34,14 +33,7 @@ NS_IMPL_RELEASE_INHERITED(ServoCSSRuleList, dom::CSSRuleList)
 NS_IMPL_CYCLE_COLLECTION_CLASS(ServoCSSRuleList)

 NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(ServoCSSRuleList)
-  for (uintptr_t& rule : tmp->mRules) {
-    if (rule > kMaxRuleType) {
-      CastToPtr(rule)->Release();
-      // Safest to set it to zero, in case someone else pokes at it
-      // during their own unlinking process.
-      rule = 0;
-    }
-  }
+  tmp->DropAllRules();
 NS_IMPL_CYCLE_COLLECTION_UNLINK_END_INHERITED(dom::CSSRuleList)
 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN_INHERITED(ServoCSSRuleList,
                                                  dom::CSSRuleList)
@ -53,6 +45,24 @@ NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN_INHERITED(ServoCSSRuleList,
  });
 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END

+void
+ServoCSSRuleList::SetParentRule(css::GroupRule* aParentRule)
+{
+  mParentRule = aParentRule;
+  EnumerateInstantiatedRules([aParentRule](css::Rule* rule) {
+    rule->SetParentRule(aParentRule);
+  });
+}
+
+void
+ServoCSSRuleList::SetStyleSheet(StyleSheet* aStyleSheet)
+{
+  mStyleSheet = aStyleSheet ? aStyleSheet->AsServo() : nullptr;
+  EnumerateInstantiatedRules([aStyleSheet](css::Rule* rule) {
+    rule->SetStyleSheet(aStyleSheet);
+  });
+}
+
 css::Rule*
 ServoCSSRuleList::GetRule(uint32_t aIndex)
 {
@ -65,7 +75,11 @@ ServoCSSRuleList::GetRule(uint32_t aIndex)
          Servo_CssRules_GetStyleRuleAt(mRawRules, aIndex).Consume());
        break;
      }
-      case nsIDOMCSSRule::MEDIA_RULE:
+      case nsIDOMCSSRule::MEDIA_RULE: {
+        ruleObj = new ServoMediaRule(
+          Servo_CssRules_GetMediaRuleAt(mRawRules, aIndex).Consume());
+        break;
+      }
      case nsIDOMCSSRule::FONT_FACE_RULE:
      case nsIDOMCSSRule::KEYFRAMES_RULE:
      case nsIDOMCSSRule::NAMESPACE_RULE:
@ -75,6 +89,7 @@ ServoCSSRuleList::GetRule(uint32_t aIndex)
        return nullptr;
    }
    ruleObj->SetStyleSheet(mStyleSheet);
+    ruleObj->SetParentRule(mParentRule);
    rule = CastToUint(ruleObj.forget().take());
    mRules[aIndex] = rule;
  }
@ -103,22 +118,36 @@ ServoCSSRuleList::EnumerateInstantiatedRules(Func aCallback)
  }
 }

+static void
+DropRule(already_AddRefed<css::Rule> aRule)
+{
+  RefPtr<css::Rule> rule = aRule;
+  rule->SetStyleSheet(nullptr);
+  rule->SetParentRule(nullptr);
+}
+
+void
+ServoCSSRuleList::DropAllRules()
+{
+  EnumerateInstantiatedRules([](css::Rule* rule) {
+    DropRule(already_AddRefed<css::Rule>(rule));
+  });
+  mRules.Clear();
+}
+
 void
 ServoCSSRuleList::DropReference()
 {
  mStyleSheet = nullptr;
-  EnumerateInstantiatedRules([](css::Rule* rule) {
-    rule->SetStyleSheet(nullptr);
-  });
+  mParentRule = nullptr;
+  DropAllRules();
 }

 nsresult
 ServoCSSRuleList::InsertRule(const nsAString& aRule, uint32_t aIndex)
 {
  NS_ConvertUTF16toUTF8 rule(aRule);
-  // XXX This needs to actually reflect whether it is nested when we
-  // support using CSSRuleList in CSSGroupingRules.
-  bool nested = false;
+  bool nested = !!mParentRule;
  uint16_t type;
  nsresult rv = Servo_CssRules_InsertRule(mRawRules, mStyleSheet->RawSheet(),
                                          &rule, aIndex, nested, &type);
@ -135,7 +164,7 @@ ServoCSSRuleList::DeleteRule(uint32_t aIndex)
  if (!NS_FAILED(rv)) {
    uintptr_t rule = mRules[aIndex];
    if (rule > kMaxRuleType) {
-      CastToPtr(rule)->Release();
+      DropRule(already_AddRefed<css::Rule>(CastToPtr(rule)));
    }
    mRules.RemoveElementAt(aIndex);
  }
@ -144,7 +173,7 @@ ServoCSSRuleList::DeleteRule(uint32_t aIndex)

 ServoCSSRuleList::~ServoCSSRuleList()
 {
-  EnumerateInstantiatedRules([](css::Rule* rule) { rule->Release(); });
+  DropAllRules();
 }

 } // namespace mozilla
--- a/layout/style/ServoCSSRuleList.h
+++ b/layout/style/ServoCSSRuleList.h
@ -16,14 +16,17 @@ namespace mozilla {

 class ServoStyleSheet;
 namespace css {
+class GroupRule;
 class Rule;
 } // namespace css

 class ServoCSSRuleList final : public dom::CSSRuleList
 {
 public:
-  ServoCSSRuleList(ServoStyleSheet* aStyleSheet,
-                   already_AddRefed<ServoCssRules> aRawRules);
+  explicit ServoCSSRuleList(already_AddRefed<ServoCssRules> aRawRules);
+  css::GroupRule* GetParentRule() const { return mParentRule; }
+  void SetParentRule(css::GroupRule* aParentRule);
+  void SetStyleSheet(StyleSheet* aSheet);

  NS_DECL_ISUPPORTS_INHERITED
  NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(ServoCSSRuleList, dom::CSSRuleList)
@ -57,8 +60,12 @@ private:
  template<typename Func>
  void EnumerateInstantiatedRules(Func aCallback);

+  void DropAllRules();
+
  // mStyleSheet may be nullptr when it drops the reference to us.
-  ServoStyleSheet* mStyleSheet;
+  ServoStyleSheet* mStyleSheet = nullptr;
+  // mParentRule is nullptr if it isn't a nested rule list.
+  css::GroupRule* mParentRule = nullptr;
  RefPtr<ServoCssRules> mRawRules;
  // Array stores either a number indicating rule type, or a pointer to
  // css::Rule. If the value is less than kMaxRuleType, the given rule
--- a/layout/style/ServoDeclarationBlock.cpp
+++ b/layout/style/ServoDeclarationBlock.cpp
@ -12,11 +12,15 @@
 namespace mozilla {

 /* static */ already_AddRefed<ServoDeclarationBlock>
-ServoDeclarationBlock::FromCssText(const nsAString& aCssText)
+ServoDeclarationBlock::FromCssText(const nsAString& aCssText,
+                                   const GeckoParserExtraData& aExtraData)
 {
  NS_ConvertUTF16toUTF8 value(aCssText);
+  nsCString baseString;
+  // FIXME (bug 1343964): Figure out a better solution for sending the base uri to servo
+  aExtraData.mBaseURI->get()->GetSpec(baseString);
  RefPtr<RawServoDeclarationBlock>
-    raw = Servo_ParseStyleAttribute(&value).Consume();
+    raw = Servo_ParseStyleAttribute(&value, &baseString, &aExtraData).Consume();
  RefPtr<ServoDeclarationBlock> decl = new ServoDeclarationBlock(raw.forget());
  return decl.forget();
 }
--- a/layout/style/ServoDeclarationBlock.h
+++ b/layout/style/ServoDeclarationBlock.h
@ -28,7 +28,8 @@ public:
  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(ServoDeclarationBlock)

  static already_AddRefed<ServoDeclarationBlock>
-  FromCssText(const nsAString& aCssText);
+  FromCssText(const nsAString& aCssText,
+              const GeckoParserExtraData& aExtraData);

  RawServoDeclarationBlock* Raw() const { return mRaw; }
  RawServoDeclarationBlock* const* RefRaw() const {
--- a/layout/style/ServoMediaList.cpp
+++ b/layout/style/ServoMediaList.cpp
@ -0,0 +1,71 @@
+/* -*- 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 http://mozilla.org/MPL/2.0/. */
+
+/* representation of media lists for servo backend */
+
+#include "mozilla/ServoMediaList.h"
+
+#include "mozilla/ServoBindings.h"
+
+namespace mozilla {
+
+already_AddRefed<dom::MediaList>
+ServoMediaList::Clone()
+{
+  // Currently MediaList::Clone() is only called from CSSStyleSheet's
+  // constructor, so we don't need to support it at the moment.
+  MOZ_ASSERT_UNREACHABLE("stylo: ServoMediaList doesn't support clone");
+  return nullptr;
+}
+
+void
+ServoMediaList::GetText(nsAString& aMediaText)
+{
+  Servo_MediaList_GetText(mRawList, &aMediaText);
+}
+
+void
+ServoMediaList::SetText(const nsAString& aMediaText)
+{
+  NS_ConvertUTF16toUTF8 mediaText(aMediaText);
+  Servo_MediaList_SetText(mRawList, &mediaText);
+}
+
+uint32_t
+ServoMediaList::Length()
+{
+  return Servo_MediaList_GetLength(mRawList);
+}
+
+void
+ServoMediaList::IndexedGetter(uint32_t aIndex, bool& aFound,
+                              nsAString& aReturn)
+{
+  aFound = Servo_MediaList_GetMediumAt(mRawList, aIndex, &aReturn);
+}
+
+nsresult
+ServoMediaList::Append(const nsAString& aNewMedium)
+{
+  if (aNewMedium.IsEmpty()) {
+    return NS_ERROR_DOM_NOT_FOUND_ERR;
+  }
+  NS_ConvertUTF16toUTF8 newMedium(aNewMedium);
+  Servo_MediaList_AppendMedium(mRawList, &newMedium);
+  return NS_OK;
+}
+
+nsresult
+ServoMediaList::Delete(const nsAString& aOldMedium)
+{
+  NS_ConvertUTF16toUTF8 oldMedium(aOldMedium);
+  if (Servo_MediaList_DeleteMedium(mRawList, &oldMedium)) {
+    return NS_OK;
+  }
+  return NS_ERROR_DOM_NOT_FOUND_ERR;
+}
+
+} // namespace mozilla
--- a/layout/style/ServoMediaList.h
+++ b/layout/style/ServoMediaList.h
@ -0,0 +1,44 @@
+/* -*- 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 http://mozilla.org/MPL/2.0/. */
+
+/* representation of media lists for servo backend */
+
+#ifndef mozilla_ServoMediaList_h
+#define mozilla_ServoMediaList_h
+
+#include "mozilla/dom/MediaList.h"
+#include "mozilla/ServoBindingTypes.h"
+
+namespace mozilla {
+
+class ServoMediaList final : public dom::MediaList
+{
+public:
+  explicit ServoMediaList(already_AddRefed<RawServoMediaList> aRawList)
+    : mRawList(aRawList) {}
+
+  already_AddRefed<dom::MediaList> Clone() final;
+
+  void GetText(nsAString& aMediaText) final;
+  void SetText(const nsAString& aMediaText) final;
+
+  uint32_t Length() final;
+  void IndexedGetter(uint32_t aIndex, bool& aFound,
+                     nsAString& aReturn) final;
+
+protected:
+  nsresult Delete(const nsAString& aOldMedium) final;
+  nsresult Append(const nsAString& aNewMedium) final;
+
+  ~ServoMediaList() {}
+
+private:
+  RefPtr<RawServoMediaList> mRawList;
+};
+
+} // namespace mozilla
+
+#endif // mozilla_ServoMediaList_h
--- a/layout/style/ServoMediaRule.cpp
+++ b/layout/style/ServoMediaRule.cpp
@ -0,0 +1,117 @@
+/* -*- 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 http://mozilla.org/MPL/2.0/. */
+
+/* representation of CSSMediaRule for stylo */
+
+#include "mozilla/ServoMediaRule.h"
+
+#include "mozilla/ServoBindings.h"
+
+using namespace mozilla::dom;
+
+namespace mozilla {
+
+ServoMediaRule::ServoMediaRule(RefPtr<RawServoMediaRule> aRawRule)
+  : CSSMediaRule(Servo_MediaRule_GetRules(aRawRule).Consume())
+  , mRawRule(Move(aRawRule))
+{
+}
+
+ServoMediaRule::~ServoMediaRule()
+{
+}
+
+NS_IMPL_ADDREF_INHERITED(ServoMediaRule, CSSMediaRule)
+NS_IMPL_RELEASE_INHERITED(ServoMediaRule, CSSMediaRule)
+
+// QueryInterface implementation for MediaRule
+NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION_INHERITED(ServoMediaRule)
+NS_INTERFACE_MAP_END_INHERITING(CSSMediaRule)
+
+NS_IMPL_CYCLE_COLLECTION_INHERITED(ServoMediaRule, CSSMediaRule,
+                                   mMediaList)
+
+/* virtual */ already_AddRefed<css::Rule>
+ServoMediaRule::Clone() const
+{
+  // Rule::Clone is only used when CSSStyleSheetInner is cloned in
+  // preparation of being mutated. However, ServoStyleSheet never clones
+  // anything, so this method should never be called.
+  MOZ_ASSERT_UNREACHABLE("Shouldn't be cloning ServoMediaRule");
+  return nullptr;
+}
+
+/* virtual */ bool
+ServoMediaRule::UseForPresentation(nsPresContext* aPresContext,
+                                   nsMediaQueryResultCacheKey& aKey)
+{
+  // GroupRule::UseForPresentation is only used in nsCSSRuleProcessor,
+  // so this should never be called.
+  MOZ_ASSERT_UNREACHABLE("Shouldn't be calling UseForPresentation");
+  return false;
+}
+
+/* virtual */ void
+ServoMediaRule::SetStyleSheet(StyleSheet* aSheet)
+{
+  if (mMediaList) {
+    mMediaList->SetStyleSheet(aSheet);
+  }
+  CSSMediaRule::SetStyleSheet(aSheet);
+}
+
+#ifdef DEBUG
+/* virtual */ void
+ServoMediaRule::List(FILE* out, int32_t aIndent) const
+{
+  nsAutoCString str;
+  for (int32_t i = 0; i < aIndent; i++) {
+    str.AppendLiteral("  ");
+  }
+  Servo_MediaRule_Debug(mRawRule, &str);
+  fprintf_stderr(out, "%s\n", str.get());
+}
+#endif
+
+// nsIDOMCSSConditionRule methods
+
+NS_IMETHODIMP
+ServoMediaRule::GetConditionText(nsAString& aConditionText)
+{
+  return Media()->GetMediaText(aConditionText);
+}
+
+NS_IMETHODIMP
+ServoMediaRule::SetConditionText(const nsAString& aConditionText)
+{
+  return Media()->SetMediaText(aConditionText);
+}
+
+/* virtual */ void
+ServoMediaRule::GetCssTextImpl(nsAString& aCssText) const
+{
+  Servo_MediaRule_GetCssText(mRawRule, &aCssText);
+}
+
+/* virtual */ dom::MediaList*
+ServoMediaRule::Media()
+{
+  if (!mMediaList) {
+    mMediaList =
+      new ServoMediaList(Servo_MediaRule_GetMedia(mRawRule).Consume());
+    mMediaList->SetStyleSheet(GetStyleSheet());
+  }
+  return mMediaList;
+}
+
+/* virtual */ size_t
+ServoMediaRule::SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const
+{
+  // TODO Implement this!
+  return aMallocSizeOf(this);
+}
+
+} // namespace mozilla
--- a/layout/style/ServoMediaRule.h
+++ b/layout/style/ServoMediaRule.h
@ -0,0 +1,57 @@
+/* -*- 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 http://mozilla.org/MPL/2.0/. */
+
+/* representation of CSSMediaRule for stylo */
+
+#ifndef mozilla_ServoMediaRule_h
+#define mozilla_ServoMediaRule_h
+
+#include "mozilla/dom/CSSMediaRule.h"
+#include "mozilla/ServoBindingTypes.h"
+
+namespace mozilla {
+
+class ServoMediaList;
+
+class ServoMediaRule final : public dom::CSSMediaRule
+{
+public:
+  explicit ServoMediaRule(RefPtr<RawServoMediaRule> aRawRule);
+
+  NS_DECL_ISUPPORTS_INHERITED
+  NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(ServoMediaRule, dom::CSSMediaRule)
+
+  already_AddRefed<css::Rule> Clone() const override;
+  bool UseForPresentation(nsPresContext* aPresContext,
+                          nsMediaQueryResultCacheKey& aKey) final;
+  void SetStyleSheet(StyleSheet* aSheet) override;
+#ifdef DEBUG
+  void List(FILE* out = stdout, int32_t aIndent = 0) const final;
+#endif
+
+  RawServoMediaRule* Raw() const { return mRawRule; }
+
+  // nsIDOMCSSConditionRule interface
+  NS_DECL_NSIDOMCSSCONDITIONRULE
+
+  // WebIDL interface
+  void GetCssTextImpl(nsAString& aCssText) const override;
+  using CSSMediaRule::SetConditionText;
+  dom::MediaList* Media() override;
+
+  size_t SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf)
+    const override;
+
+private:
+  virtual ~ServoMediaRule();
+
+  RefPtr<RawServoMediaRule> mRawRule;
+  RefPtr<ServoMediaList> mMediaList;
+};
+
+} // namespace mozilla
+
+#endif // mozilla_ServoMediaRule_h
--- a/layout/style/ServoStyleSet.cpp
+++ b/layout/style/ServoStyleSet.cpp
@ -11,6 +11,7 @@
 #include "mozilla/dom/ChildIterator.h"
 #include "mozilla/dom/Element.h"
 #include "mozilla/dom/ElementInlines.h"
+#include "mozilla/dom/KeyframeEffectReadOnly.h"
 #include "nsCSSAnonBoxes.h"
 #include "nsCSSPseudoElements.h"
 #include "nsHTMLStyleSheet.h"
@ -710,6 +711,24 @@ ServoStyleSet::FillKeyframesForName(const nsString& aName,
                                             &aKeyframes);
 }

+nsTArray<ComputedKeyframeValues>
+ServoStyleSet::GetComputedKeyframeValuesFor(const nsTArray<Keyframe>& aKeyframes,
+                                            dom::Element* aElement,
+                                            const ServoComputedStyleValues& aServoValues)
+{
+  nsTArray<ComputedKeyframeValues> result(aKeyframes.Length());
+
+  // Construct each nsTArray<PropertyStyleAnimationValuePair> here.
+  result.AppendElements(aKeyframes.Length());
+
+  Servo_GetComputedKeyframeValues(&aKeyframes,
+                                  aServoValues.mCurrentStyle,
+                                  aServoValues.mParentStyle,
+                                  mRawSet.get(),
+                                  &result);
+  return result;
+}
+
 void
 ServoStyleSet::RebuildData()
 {
@ -728,7 +747,7 @@ ServoStyleSet::ClearNonInheritingStyleContexts()
 {
  for (RefPtr<nsStyleContext>& ptr : mNonInheritingStyleContexts) {
    ptr = nullptr;
-  }  
+  }
 }

 already_AddRefed<ServoComputedValues>
--- a/Show More
+++ b/Show More