Adding upstream version 86.0.1.upstream/86.0.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 5734 insertions, 0 deletions

diff --git a/browser/components/BrowserGlue.jsm b/browser/components/BrowserGlue.jsm
new file mode 100644
index 0000000000..0c73eeef2e
--- /dev/null
+++ b/browser/components/BrowserGlue.jsm
@@ -0,0 +1,5734 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+var EXPORTED_SYMBOLS = [
+  "AboutHomeStartupCache",
+  "BrowserGlue",
+  "ContentPermissionPrompt",
+  "DefaultBrowserCheck",
+];
+
+const { XPCOMUtils } = ChromeUtils.import(
+  "resource://gre/modules/XPCOMUtils.jsm"
+);
+const { Services } = ChromeUtils.import("resource://gre/modules/Services.jsm");
+const { AppConstants } = ChromeUtils.import(
+  "resource://gre/modules/AppConstants.jsm"
+);
+
+XPCOMUtils.defineLazyModuleGetters(this, {
+  AboutNewTab: "resource:///modules/AboutNewTab.jsm",
+  ActorManagerParent: "resource://gre/modules/ActorManagerParent.jsm",
+  AddonManager: "resource://gre/modules/AddonManager.jsm",
+  AppMenuNotifications: "resource://gre/modules/AppMenuNotifications.jsm",
+  ASRouterDefaultConfig:
+    "resource://activity-stream/lib/ASRouterDefaultConfig.jsm",
+  ASRouterNewTabHook: "resource://activity-stream/lib/ASRouterNewTabHook.jsm",
+  ASRouter: "resource://activity-stream/lib/ASRouter.jsm",
+  AsyncShutdown: "resource://gre/modules/AsyncShutdown.jsm",
+  Blocklist: "resource://gre/modules/Blocklist.jsm",
+  BookmarkHTMLUtils: "resource://gre/modules/BookmarkHTMLUtils.jsm",
+  BookmarkJSONUtils: "resource://gre/modules/BookmarkJSONUtils.jsm",
+  BrowserSearchTelemetry: "resource:///modules/BrowserSearchTelemetry.jsm",
+  BrowserUsageTelemetry: "resource:///modules/BrowserUsageTelemetry.jsm",
+  BrowserUtils: "resource://gre/modules/BrowserUtils.jsm",
+  BrowserWindowTracker: "resource:///modules/BrowserWindowTracker.jsm",
+  ContextualIdentityService:
+    "resource://gre/modules/ContextualIdentityService.jsm",
+  Corroborate: "resource://gre/modules/Corroborate.jsm",
+  DeferredTask: "resource://gre/modules/DeferredTask.jsm",
+  Discovery: "resource:///modules/Discovery.jsm",
+  DoHController: "resource:///modules/DoHController.jsm",
+  DownloadsViewableInternally:
+    "resource:///modules/DownloadsViewableInternally.jsm",
+  E10SUtils: "resource://gre/modules/E10SUtils.jsm",
+  ExtensionsUI: "resource:///modules/ExtensionsUI.jsm",
+  ExperimentAPI: "resource://messaging-system/experiments/ExperimentAPI.jsm",
+  FeatureGate: "resource://featuregates/FeatureGate.jsm",
+  FirefoxMonitor: "resource:///modules/FirefoxMonitor.jsm",
+  FxAccounts: "resource://gre/modules/FxAccounts.jsm",
+  HomePage: "resource:///modules/HomePage.jsm",
+  Integration: "resource://gre/modules/Integration.jsm",
+  Log: "resource://gre/modules/Log.jsm",
+  LoginBreaches: "resource:///modules/LoginBreaches.jsm",
+  NetUtil: "resource://gre/modules/NetUtil.jsm",
+  NewTabUtils: "resource://gre/modules/NewTabUtils.jsm",
+  Normandy: "resource://normandy/Normandy.jsm",
+  OS: "resource://gre/modules/osfile.jsm",
+  OsEnvironment: "resource://gre/modules/OsEnvironment.jsm",
+  PageActions: "resource:///modules/PageActions.jsm",
+  PageThumbs: "resource://gre/modules/PageThumbs.jsm",
+  PdfJs: "resource://pdf.js/PdfJs.jsm",
+  PermissionUI: "resource:///modules/PermissionUI.jsm",
+  PlacesBackups: "resource://gre/modules/PlacesBackups.jsm",
+  PlacesDBUtils: "resource://gre/modules/PlacesDBUtils.jsm",
+  PlacesUIUtils: "resource:///modules/PlacesUIUtils.jsm",
+  PlacesUtils: "resource://gre/modules/PlacesUtils.jsm",
+  PluralForm: "resource://gre/modules/PluralForm.jsm",
+  PrivateBrowsingUtils: "resource://gre/modules/PrivateBrowsingUtils.jsm",
+  ProcessHangMonitor: "resource:///modules/ProcessHangMonitor.jsm",
+  PublicSuffixList: "resource://gre/modules/netwerk-dns/PublicSuffixList.jsm",
+  RemoteSettings: "resource://services-settings/remote-settings.js",
+  RemoteSecuritySettings:
+    "resource://gre/modules/psm/RemoteSecuritySettings.jsm",
+  RFPHelper: "resource://gre/modules/RFPHelper.jsm",
+  SafeBrowsing: "resource://gre/modules/SafeBrowsing.jsm",
+  Sanitizer: "resource:///modules/Sanitizer.jsm",
+  SaveToPocket: "chrome://pocket/content/SaveToPocket.jsm",
+  SearchSERPTelemetry: "resource:///modules/SearchSERPTelemetry.jsm",
+  SessionStartup: "resource:///modules/sessionstore/SessionStartup.jsm",
+  SessionStore: "resource:///modules/sessionstore/SessionStore.jsm",
+  TabCrashHandler: "resource:///modules/ContentCrashHandlers.jsm",
+  TabUnloader: "resource:///modules/TabUnloader.jsm",
+  TelemetryUtils: "resource://gre/modules/TelemetryUtils.jsm",
+  TRRRacer: "resource:///modules/TRRPerformance.jsm",
+  UIState: "resource://services-sync/UIState.jsm",
+  WebChannel: "resource://gre/modules/WebChannel.jsm",
+  WindowsRegistry: "resource://gre/modules/WindowsRegistry.jsm",
+});
+
+// eslint-disable-next-line no-unused-vars
+XPCOMUtils.defineLazyModuleGetters(this, {
+  AboutLoginsParent: "resource:///modules/AboutLoginsParent.jsm",
+  PluginManager: "resource:///actors/PluginParent.jsm",
+});
+
+// Modules requiring an initialization method call.
+let initializedModules = {};
+[
+  [
+    "ContentPrefServiceParent",
+    "resource://gre/modules/ContentPrefServiceParent.jsm",
+    "alwaysInit",
+  ],
+  ["UpdateListener", "resource://gre/modules/UpdateListener.jsm", "init"],
+].forEach(([name, resource, init]) => {
+  XPCOMUtils.defineLazyGetter(this, name, () => {
+    ChromeUtils.import(resource, initializedModules);
+    initializedModules[name][init]();
+    return initializedModules[name];
+  });
+});
+
+XPCOMUtils.defineLazyServiceGetter(
+  this,
+  "PushService",
+  "@mozilla.org/push/Service;1",
+  "nsIPushService"
+);
+
+const PREF_PDFJS_ISDEFAULT_CACHE_STATE = "pdfjs.enabledCache.state";
+
+/**
+ * Fission-compatible JSProcess implementations.
+ * Each actor options object takes the form of a ProcessActorOptions dictionary.
+ * Detailed documentation of these options is in dom/docs/ipc/jsactors.rst,
+ * available at https://firefox-source-docs.mozilla.org/dom/ipc/jsactors.html
+ */
+let JSPROCESSACTORS = {
+  // Miscellaneous stuff that needs to be initialized per process.
+  BrowserProcess: {
+    child: {
+      moduleURI: "resource:///actors/BrowserProcessChild.jsm",
+      observers: [
+        // WebRTC related notifications. They are here to avoid loading WebRTC
+        // components when not needed.
+        "getUserMedia:request",
+        "recording-device-stopped",
+        "PeerConnection:request",
+        "recording-device-events",
+        "recording-window-ended",
+      ],
+    },
+  },
+
+  RefreshBlockerObserver: {
+    child: {
+      moduleURI: "resource:///actors/RefreshBlockerChild.jsm",
+      observers: [
+        "webnavigation-create",
+        "chrome-webnavigation-create",
+        "webnavigation-destroy",
+        "chrome-webnavigation-destroy",
+      ],
+    },
+
+    enablePreference: "accessibility.blockautorefresh",
+    onPreferenceChanged: (prefName, prevValue, isEnabled) => {
+      BrowserWindowTracker.orderedWindows.forEach(win => {
+        for (let browser of win.gBrowser.browsers) {
+          try {
+            browser.sendMessageToActor(
+              "PreferenceChanged",
+              { isEnabled },
+              "RefreshBlocker",
+              "all"
+            );
+          } catch (ex) {}
+        }
+      });
+    },
+  },
+};
+
+/**
+ * Fission-compatible JSWindowActor implementations.
+ * Detailed documentation of these options is in dom/docs/ipc/jsactors.rst,
+ * available at https://firefox-source-docs.mozilla.org/dom/ipc/jsactors.html
+ */
+let JSWINDOWACTORS = {
+  AboutLogins: {
+    parent: {
+      moduleURI: "resource:///actors/AboutLoginsParent.jsm",
+    },
+    child: {
+      moduleURI: "resource:///actors/AboutLoginsChild.jsm",
+      events: {
+        AboutLoginsCopyLoginDetail: { wantUntrusted: true },
+        AboutLoginsCreateLogin: { wantUntrusted: true },
+        AboutLoginsDeleteLogin: { wantUntrusted: true },
+        AboutLoginsDismissBreachAlert: { wantUntrusted: true },
+        AboutLoginsImportFromBrowser: { wantUntrusted: true },
+        AboutLoginsImportFromFile: { wantUntrusted: true },
+        AboutLoginsInit: { wantUntrusted: true },
+        AboutLoginsGetHelp: { wantUntrusted: true },
+        AboutLoginsOpenPreferences: { wantUntrusted: true },
+        AboutLoginsOpenSite: { wantUntrusted: true },
+        AboutLoginsRecordTelemetryEvent: { wantUntrusted: true },
+        AboutLoginsRemoveAllLogins: { wantUntrusted: true },
+        AboutLoginsSortChanged: { wantUntrusted: true },
+        AboutLoginsSyncEnable: { wantUntrusted: true },
+        AboutLoginsSyncOptions: { wantUntrusted: true },
+        AboutLoginsUpdateLogin: { wantUntrusted: true },
+        AboutLoginsExportPasswords: { wantUntrusted: true },
+      },
+    },
+    matches: ["about:logins", "about:logins?*"],
+  },
+
+  AboutNewInstall: {
+    parent: {
+      moduleURI: "resource:///actors/AboutNewInstallParent.jsm",
+    },
+    child: {
+      moduleURI: "resource:///actors/AboutNewInstallChild.jsm",
+
+      events: {
+        DOMWindowCreated: { capture: true },
+      },
+    },
+
+    matches: ["about:newinstall"],
+  },
+
+  AboutNewTab: {
+    parent: {
+      moduleURI: "resource:///actors/AboutNewTabParent.jsm",
+    },
+    child: {
+      moduleURI: "resource:///actors/AboutNewTabChild.jsm",
+      events: {
+        DOMContentLoaded: {},
+        pageshow: {},
+        visibilitychange: {},
+      },
+    },
+    // The wildcard on about:newtab is for the ?endpoint query parameter
+    // that is used for snippets debugging. The wildcard for about:home
+    // is similar, and also allows for falling back to loading the
+    // about:home document dynamically if an attempt is made to load
+    // about:home?jscache from the AboutHomeStartupCache as a top-level
+    // load.
+    matches: ["about:home*", "about:welcome", "about:newtab*"],
+    remoteTypes: ["privilegedabout"],
+  },
+
+  AboutPlugins: {
+    parent: {
+      moduleURI: "resource:///actors/AboutPluginsParent.jsm",
+    },
+    child: {
+      moduleURI: "resource:///actors/AboutPluginsChild.jsm",
+
+      events: {
+        DOMWindowCreated: { capture: true },
+      },
+    },
+
+    matches: ["about:plugins"],
+  },
+
+  AboutPrivateBrowsing: {
+    parent: {
+      moduleURI: "resource:///actors/AboutPrivateBrowsingParent.jsm",
+    },
+    child: {
+      moduleURI: "resource:///actors/AboutPrivateBrowsingChild.jsm",
+
+      events: {
+        DOMWindowCreated: { capture: true },
+      },
+    },
+
+    matches: ["about:privatebrowsing"],
+  },
+
+  AboutProtections: {
+    parent: {
+      moduleURI: "resource:///actors/AboutProtectionsParent.jsm",
+    },
+    child: {
+      moduleURI: "resource:///actors/AboutProtectionsChild.jsm",
+
+      events: {
+        DOMWindowCreated: { capture: true },
+      },
+    },
+
+    matches: ["about:protections", "about:protections?*"],
+  },
+
+  AboutReader: {
+    parent: {
+      moduleURI: "resource:///actors/AboutReaderParent.jsm",
+    },
+    child: {
+      moduleURI: "resource:///actors/AboutReaderChild.jsm",
+      events: {
+        DOMContentLoaded: {},
+        pageshow: { mozSystemGroup: true },
+        pagehide: { mozSystemGroup: true },
+      },
+    },
+    messageManagerGroups: ["browsers"],
+  },
+
+  AboutTabCrashed: {
+    parent: {
+      moduleURI: "resource:///actors/AboutTabCrashedParent.jsm",
+    },
+    child: {
+      moduleURI: "resource:///actors/AboutTabCrashedChild.jsm",
+
+      events: {
+        DOMWindowCreated: { capture: true },
+      },
+    },
+
+    matches: ["about:tabcrashed*"],
+  },
+
+  AboutWelcome: {
+    parent: {
+      moduleURI: "resource:///actors/AboutWelcomeParent.jsm",
+    },
+    child: {
+      moduleURI: "resource:///actors/AboutWelcomeChild.jsm",
+      events: {
+        // This is added so the actor instantiates immediately and makes
+        // methods available to the page js on load.
+        DOMWindowCreated: {},
+      },
+    },
+    matches: ["about:welcome"],
+    remoteTypes: ["privilegedabout"],
+
+    // See Bug 1618306
+    // Remove this preference check when we turn on separate about:welcome for all users.
+    enablePreference: "browser.aboutwelcome.enabled",
+  },
+
+  BlockedSite: {
+    parent: {
+      moduleURI: "resource:///actors/BlockedSiteParent.jsm",
+    },
+    child: {
+      moduleURI: "resource:///actors/BlockedSiteChild.jsm",
+      events: {
+        AboutBlockedLoaded: { wantUntrusted: true },
+        click: {},
+      },
+    },
+    matches: ["about:blocked?*"],
+    allFrames: true,
+  },
+
+  BrowserTab: {
+    parent: {
+      moduleURI: "resource:///actors/BrowserTabParent.jsm",
+    },
+    child: {
+      moduleURI: "resource:///actors/BrowserTabChild.jsm",
+
+      events: {
+        DOMWindowCreated: {},
+        MozAfterPaint: {},
+      },
+    },
+
+    messageManagerGroups: ["browsers"],
+  },
+
+  ClickHandler: {
+    parent: {
+      moduleURI: "resource:///actors/ClickHandlerParent.jsm",
+    },
+    child: {
+      moduleURI: "resource:///actors/ClickHandlerChild.jsm",
+      events: {
+        click: { capture: true, mozSystemGroup: true },
+        auxclick: { capture: true, mozSystemGroup: true },
+      },
+    },
+
+    allFrames: true,
+  },
+
+  // Collects description and icon information from meta tags.
+  ContentMeta: {
+    parent: {
+      moduleURI: "resource:///actors/ContentMetaParent.jsm",
+    },
+
+    child: {
+      moduleURI: "resource:///actors/ContentMetaChild.jsm",
+      events: {
+        DOMMetaAdded: {},
+      },
+    },
+  },
+
+  ContentSearch: {
+    parent: {
+      moduleURI: "resource:///actors/ContentSearchParent.jsm",
+    },
+    child: {
+      moduleURI: "resource:///actors/ContentSearchChild.jsm",
+      events: {
+        ContentSearchClient: { capture: true, wantUntrusted: true },
+      },
+    },
+    matches: [
+      "about:home",
+      "about:welcome",
+      "about:newtab",
+      "about:privatebrowsing",
+      "about:test-about-content-search-ui",
+    ],
+    remoteTypes: ["privilegedabout"],
+  },
+
+  ContextMenu: {
+    parent: {
+      moduleURI: "resource:///actors/ContextMenuParent.jsm",
+    },
+
+    child: {
+      moduleURI: "resource:///actors/ContextMenuChild.jsm",
+      events: {
+        contextmenu: { mozSystemGroup: true },
+      },
+    },
+
+    allFrames: true,
+  },
+
+  DecoderDoctor: {
+    parent: {
+      moduleURI: "resource:///actors/DecoderDoctorParent.jsm",
+    },
+
+    child: {
+      moduleURI: "resource:///actors/DecoderDoctorChild.jsm",
+      observers: ["decoder-doctor-notification"],
+    },
+
+    messageManagerGroups: ["browsers"],
+    allFrames: true,
+  },
+
+  DOMFullscreen: {
+    parent: {
+      moduleURI: "resource:///actors/DOMFullscreenParent.jsm",
+    },
+
+    child: {
+      moduleURI: "resource:///actors/DOMFullscreenChild.jsm",
+      group: "browsers",
+      events: {
+        "MozDOMFullscreen:Request": {},
+        "MozDOMFullscreen:Entered": {},
+        "MozDOMFullscreen:NewOrigin": {},
+        "MozDOMFullscreen:Exit": {},
+        "MozDOMFullscreen:Exited": {},
+      },
+    },
+
+    allFrames: true,
+  },
+
+  EncryptedMedia: {
+    parent: {
+      moduleURI: "resource:///actors/EncryptedMediaParent.jsm",
+    },
+
+    child: {
+      moduleURI: "resource:///actors/EncryptedMediaChild.jsm",
+      observers: ["mediakeys-request"],
+    },
+
+    messageManagerGroups: ["browsers"],
+    allFrames: true,
+  },
+
+  FormValidation: {
+    parent: {
+      moduleURI: "resource:///actors/FormValidationParent.jsm",
+    },
+
+    child: {
+      moduleURI: "resource:///actors/FormValidationChild.jsm",
+      events: {
+        MozInvalidForm: {},
+      },
+    },
+
+    allFrames: true,
+  },
+
+  LightweightTheme: {
+    child: {
+      moduleURI: "resource:///actors/LightweightThemeChild.jsm",
+      events: {
+        pageshow: { mozSystemGroup: true },
+      },
+    },
+    includeChrome: true,
+    allFrames: true,
+    matches: [
+      "about:home",
+      "about:newtab",
+      "about:welcome",
+      "chrome://browser/content/syncedtabs/sidebar.xhtml",
+      "chrome://browser/content/places/historySidebar.xhtml",
+      "chrome://browser/content/places/bookmarksSidebar.xhtml",
+    ],
+  },
+
+  LinkHandler: {
+    parent: {
+      moduleURI: "resource:///actors/LinkHandlerParent.jsm",
+    },
+    child: {
+      moduleURI: "resource:///actors/LinkHandlerChild.jsm",
+      events: {
+        DOMHeadElementParsed: {},
+        DOMLinkAdded: {},
+        DOMLinkChanged: {},
+        pageshow: {},
+        pagehide: {},
+      },
+    },
+  },
+
+  NetError: {
+    parent: {
+      moduleURI: "resource:///actors/NetErrorParent.jsm",
+    },
+    child: {
+      moduleURI: "resource:///actors/NetErrorChild.jsm",
+      events: {
+        DOMWindowCreated: {},
+        click: {},
+      },
+    },
+
+    matches: ["about:certerror?*", "about:neterror?*"],
+    allFrames: true,
+  },
+
+  PageInfo: {
+    child: {
+      moduleURI: "resource:///actors/PageInfoChild.jsm",
+    },
+
+    allFrames: true,
+  },
+
+  PageStyle: {
+    parent: {
+      moduleURI: "resource:///actors/PageStyleParent.jsm",
+    },
+    child: {
+      moduleURI: "resource:///actors/PageStyleChild.jsm",
+      events: {
+        pageshow: {},
+      },
+    },
+
+    // Only matching web pages, as opposed to internal about:, chrome: or
+    // resource: pages. See https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/Match_patterns
+    matches: ["*://*/*", "file:///*"],
+    messageManagerGroups: ["browsers"],
+    allFrames: true,
+  },
+
+  Pdfjs: {
+    parent: {
+      moduleURI: "resource://pdf.js/PdfjsParent.jsm",
+    },
+    child: {
+      moduleURI: "resource://pdf.js/PdfjsChild.jsm",
+    },
+    allFrames: true,
+  },
+
+  Plugin: {
+    parent: {
+      moduleURI: "resource:///actors/PluginParent.jsm",
+    },
+    child: {
+      moduleURI: "resource:///actors/PluginChild.jsm",
+      events: {
+        PluginBindingAttached: { capture: true, wantUntrusted: true },
+        PluginCrashed: { capture: true },
+        PluginOutdated: { capture: true },
+        PluginInstantiated: { capture: true },
+        PluginRemoved: { capture: true },
+        HiddenPlugin: { capture: true },
+      },
+
+      observers: ["decoder-doctor-notification"],
+    },
+
+    allFrames: true,
+  },
+
+  PointerLock: {
+    parent: {
+      moduleURI: "resource:///actors/PointerLockParent.jsm",
+    },
+    child: {
+      moduleURI: "resource:///actors/PointerLockChild.jsm",
+      events: {
+        "MozDOMPointerLock:Entered": {},
+        "MozDOMPointerLock:Exited": {},
+      },
+    },
+
+    messageManagerGroups: ["browsers"],
+    allFrames: true,
+  },
+
+  Prompt: {
+    parent: {
+      moduleURI: "resource:///actors/PromptParent.jsm",
+    },
+    includeChrome: true,
+    allFrames: true,
+  },
+
+  RefreshBlocker: {
+    parent: {
+      moduleURI: "resource:///actors/RefreshBlockerParent.jsm",
+    },
+    child: {
+      moduleURI: "resource:///actors/RefreshBlockerChild.jsm",
+    },
+
+    messageManagerGroups: ["browsers"],
+    enablePreference: "accessibility.blockautorefresh",
+  },
+
+  SearchSERPTelemetry: {
+    parent: {
+      moduleURI: "resource:///actors/SearchSERPTelemetryParent.jsm",
+    },
+    child: {
+      moduleURI: "resource:///actors/SearchSERPTelemetryChild.jsm",
+      events: {
+        DOMContentLoaded: {},
+        pageshow: { mozSystemGroup: true },
+        unload: {},
+      },
+    },
+  },
+
+  ShieldFrame: {
+    parent: {
+      moduleURI: "resource://normandy-content/ShieldFrameParent.jsm",
+    },
+    child: {
+      moduleURI: "resource://normandy-content/ShieldFrameChild.jsm",
+      events: {
+        pageshow: {},
+        pagehide: {},
+        ShieldPageEvent: { wantUntrusted: true },
+      },
+    },
+    matches: ["about:studies"],
+  },
+
+  ASRouter: {
+    parent: {
+      moduleURI: "resource:///actors/ASRouterParent.jsm",
+    },
+    child: {
+      moduleURI: "resource:///actors/ASRouterChild.jsm",
+      events: {
+        // This is added so the actor instantiates immediately and makes
+        // methods available to the page js on load.
+        DOMWindowCreated: {},
+      },
+    },
+    matches: ["about:home*", "about:newtab*", "about:welcome*"],
+    remoteTypes: ["privilegedabout"],
+  },
+
+  SwitchDocumentDirection: {
+    child: {
+      moduleURI: "resource:///actors/SwitchDocumentDirectionChild.jsm",
+    },
+
+    allFrames: true,
+  },
+
+  Translation: {
+    parent: {
+      moduleURI: "resource:///modules/translation/TranslationParent.jsm",
+    },
+    child: {
+      moduleURI: "resource:///modules/translation/TranslationChild.jsm",
+      events: {
+        pageshow: {},
+        load: { mozSystemGroup: true, capture: true },
+      },
+    },
+    enablePreference: "browser.translation.detectLanguage",
+  },
+
+  UITour: {
+    parent: {
+      moduleURI: "resource:///modules/UITourParent.jsm",
+    },
+    child: {
+      moduleURI: "resource:///modules/UITourChild.jsm",
+      events: {
+        mozUITour: { wantUntrusted: true },
+      },
+    },
+  },
+
+  WebRTC: {
+    parent: {
+      moduleURI: "resource:///actors/WebRTCParent.jsm",
+    },
+    child: {
+      moduleURI: "resource:///actors/WebRTCChild.jsm",
+    },
+
+    allFrames: true,
+  },
+};
+
+(function earlyBlankFirstPaint() {
+  let startTime = Cu.now();
+  if (
+    AppConstants.platform == "macosx" ||
+    !Services.prefs.getBoolPref("browser.startup.blankWindow", false)
+  ) {
+    return;
+  }
+
+  // Until bug 1450626 and bug 1488384 are fixed, skip the blank window when
+  // using a non-default theme.
+  if (
+    Services.prefs.getCharPref(
+      "extensions.activeThemeID",
+      "default-theme@mozilla.org"
+    ) != "default-theme@mozilla.org"
+  ) {
+    return;
+  }
+
+  let store = Services.xulStore;
+  let getValue = attr =>
+    store.getValue(AppConstants.BROWSER_CHROME_URL, "main-window", attr);
+  let width = getValue("width");
+  let height = getValue("height");
+
+  // The clean profile case isn't handled yet. Return early for now.
+  if (!width || !height) {
+    return;
+  }
+
+  let browserWindowFeatures =
+    "chrome,all,dialog=no,extrachrome,menubar,resizable,scrollbars,status," +
+    "location,toolbar,personalbar";
+  let win = Services.ww.openWindow(
+    null,
+    "about:blank",
+    null,
+    browserWindowFeatures,
+    null
+  );
+
+  // Hide the titlebar if the actual browser window will draw in it.
+  let hiddenTitlebar = Services.prefs.getBoolPref(
+    "browser.tabs.drawInTitlebar",
+    win.matchMedia("(-moz-gtk-csd-hide-titlebar-by-default)").matches
+  );
+  if (hiddenTitlebar) {
+    win.windowUtils.setChromeMargin(0, 2, 2, 2);
+  }
+
+  let docElt = win.document.documentElement;
+  docElt.setAttribute("screenX", getValue("screenX"));
+  docElt.setAttribute("screenY", getValue("screenY"));
+
+  // The sizemode="maximized" attribute needs to be set before first paint.
+  let sizemode = getValue("sizemode");
+  if (sizemode == "maximized") {
+    docElt.setAttribute("sizemode", sizemode);
+
+    // Set the size to use when the user leaves the maximized mode.
+    // The persisted size is the outer size, but the height/width
+    // attributes set the inner size.
+    let appWin = win.docShell.treeOwner
+      .QueryInterface(Ci.nsIInterfaceRequestor)
+      .getInterface(Ci.nsIAppWindow);
+    height -= appWin.outerToInnerHeightDifferenceInCSSPixels;
+    width -= appWin.outerToInnerWidthDifferenceInCSSPixels;
+    docElt.setAttribute("height", height);
+    docElt.setAttribute("width", width);
+  } else {
+    // Setting the size of the window in the features string instead of here
+    // causes the window to grow by the size of the titlebar.
+    win.resizeTo(width, height);
+  }
+
+  // Set this before showing the window so that graphics code can use it to
+  // decide to skip some expensive code paths (eg. starting the GPU process).
+  docElt.setAttribute("windowtype", "navigator:blank");
+
+  // The window becomes visible after OnStopRequest, so make this happen now.
+  win.stop();
+
+  ChromeUtils.addProfilerMarker("earlyBlankFirstPaint", startTime);
+  win.openTime = Cu.now();
+
+  let { TelemetryTimestamps } = ChromeUtils.import(
+    "resource://gre/modules/TelemetryTimestamps.jsm"
+  );
+  TelemetryTimestamps.add("blankWindowShown");
+})();
+
+XPCOMUtils.defineLazyGetter(
+  this,
+  "WeaveService",
+  () => Cc["@mozilla.org/weave/service;1"].getService().wrappedJSObject
+);
+
+if (AppConstants.MOZ_CRASHREPORTER) {
+  XPCOMUtils.defineLazyModuleGetters(this, {
+    UnsubmittedCrashHandler: "resource:///modules/ContentCrashHandlers.jsm",
+  });
+}
+
+XPCOMUtils.defineLazyGetter(this, "gBrandBundle", function() {
+  return Services.strings.createBundle(
+    "chrome://branding/locale/brand.properties"
+  );
+});
+
+XPCOMUtils.defineLazyGetter(this, "gBrowserBundle", function() {
+  return Services.strings.createBundle(
+    "chrome://browser/locale/browser.properties"
+  );
+});
+
+XPCOMUtils.defineLazyGetter(this, "gTabbrowserBundle", function() {
+  return Services.strings.createBundle(
+    "chrome://browser/locale/tabbrowser.properties"
+  );
+});
+
+const global = this;
+
+const listeners = {
+  observers: {
+    "update-downloading": ["UpdateListener"],
+    "update-staged": ["UpdateListener"],
+    "update-downloaded": ["UpdateListener"],
+    "update-available": ["UpdateListener"],
+    "update-error": ["UpdateListener"],
+    "update-swap": ["UpdateListener"],
+    "gmp-plugin-crash": ["PluginManager"],
+    "plugin-crashed": ["PluginManager"],
+  },
+
+  observe(subject, topic, data) {
+    for (let module of this.observers[topic]) {
+      try {
+        global[module].observe(subject, topic, data);
+      } catch (e) {
+        Cu.reportError(e);
+      }
+    }
+  },
+
+  init() {
+    for (let observer of Object.keys(this.observers)) {
+      Services.obs.addObserver(this, observer);
+    }
+  },
+};
+
+// Seconds of idle before trying to create a bookmarks backup.
+const BOOKMARKS_BACKUP_IDLE_TIME_SEC = 8 * 60;
+// Minimum interval between backups.  We try to not create more than one backup
+// per interval.
+const BOOKMARKS_BACKUP_MIN_INTERVAL_DAYS = 1;
+// Maximum interval between backups.  If the last backup is older than these
+// days we will try to create a new one more aggressively.
+const BOOKMARKS_BACKUP_MAX_INTERVAL_DAYS = 3;
+// Seconds of idle time before the late idle tasks will be scheduled.
+const LATE_TASKS_IDLE_TIME_SEC = 20;
+// Time after we stop tracking startup crashes.
+const STARTUP_CRASHES_END_DELAY_MS = 30 * 1000;
+
+/*
+ * OS X has the concept of zero-window sessions and therefore ignores the
+ * browser-lastwindow-close-* topics.
+ */
+const OBSERVE_LASTWINDOW_CLOSE_TOPICS = AppConstants.platform != "macosx";
+
+function BrowserGlue() {
+  XPCOMUtils.defineLazyServiceGetter(
+    this,
+    "_userIdleService",
+    "@mozilla.org/widget/useridleservice;1",
+    "nsIUserIdleService"
+  );
+
+  XPCOMUtils.defineLazyGetter(this, "_distributionCustomizer", function() {
+    const { DistributionCustomizer } = ChromeUtils.import(
+      "resource:///modules/distribution.js"
+    );
+    return new DistributionCustomizer();
+  });
+
+  XPCOMUtils.defineLazyServiceGetter(
+    this,
+    "AlertsService",
+    "@mozilla.org/alerts-service;1",
+    "nsIAlertsService"
+  );
+
+  this._init();
+}
+
+BrowserGlue.prototype = {
+  _saveSession: false,
+  _migrationImportsDefaultBookmarks: false,
+  _placesBrowserInitComplete: false,
+  _isNewProfile: undefined,
+
+  _setPrefToSaveSession: function BG__setPrefToSaveSession(aForce) {
+    if (!this._saveSession && !aForce) {
+      return;
+    }
+
+    if (!PrivateBrowsingUtils.permanentPrivateBrowsing) {
+      Services.prefs.setBoolPref(
+        "browser.sessionstore.resume_session_once",
+        true
+      );
+    }
+
+    // This method can be called via [NSApplication terminate:] on Mac, which
+    // ends up causing prefs not to be flushed to disk, so we need to do that
+    // explicitly here. See bug 497652.
+    Services.prefs.savePrefFile(null);
+  },
+
+  _setSyncAutoconnectDelay: function BG__setSyncAutoconnectDelay() {
+    // Assume that a non-zero value for services.sync.autoconnectDelay should override
+    if (Services.prefs.prefHasUserValue("services.sync.autoconnectDelay")) {
+      let prefDelay = Services.prefs.getIntPref(
+        "services.sync.autoconnectDelay"
+      );
+
+      if (prefDelay > 0) {
+        return;
+      }
+    }
+
+    // delays are in seconds
+    const MAX_DELAY = 300;
+    let delay = 3;
+    for (let win of Services.wm.getEnumerator("navigator:browser")) {
+      // browser windows without a gBrowser almost certainly means we are
+      // shutting down, so instead of just ignoring that window we abort.
+      if (win.closed || !win.gBrowser) {
+        return;
+      }
+      delay += win.gBrowser.tabs.length;
+    }
+    delay = delay <= MAX_DELAY ? delay : MAX_DELAY;
+
+    const { Weave } = ChromeUtils.import("resource://services-sync/main.js");
+    Weave.Service.scheduler.delayedAutoConnect(delay);
+  },
+
+  // nsIObserver implementation
+  observe: async function BG_observe(subject, topic, data) {
+    switch (topic) {
+      case "notifications-open-settings":
+        this._openPreferences("privacy-permissions");
+        break;
+      case "final-ui-startup":
+        this._beforeUIStartup();
+        break;
+      case "browser-delayed-startup-finished":
+        this._onFirstWindowLoaded(subject);
+        Services.obs.removeObserver(this, "browser-delayed-startup-finished");
+        break;
+      case "sessionstore-windows-restored":
+        this._onWindowsRestored();
+        break;
+      case "browser:purge-session-history":
+        // reset the console service's error buffer
+        Services.console.logStringMessage(null); // clear the console (in case it's open)
+        Services.console.reset();
+        break;
+      case "restart-in-safe-mode":
+        this._onSafeModeRestart();
+        break;
+      case "quit-application-requested":
+        this._onQuitRequest(subject, data);
+        break;
+      case "quit-application-granted":
+        this._onQuitApplicationGranted();
+        break;
+      case "browser-lastwindow-close-requested":
+        if (OBSERVE_LASTWINDOW_CLOSE_TOPICS) {
+          // The application is not actually quitting, but the last full browser
+          // window is about to be closed.
+          this._onQuitRequest(subject, "lastwindow");
+        }
+        break;
+      case "browser-lastwindow-close-granted":
+        if (OBSERVE_LASTWINDOW_CLOSE_TOPICS) {
+          this._setPrefToSaveSession();
+        }
+        break;
+      case "weave:service:ready":
+        this._setSyncAutoconnectDelay();
+        break;
+      case "fxaccounts:onverified":
+        this._onThisDeviceConnected();
+        break;
+      case "fxaccounts:device_connected":
+        this._onDeviceConnected(data);
+        break;
+      case "fxaccounts:verify_login":
+        this._onVerifyLoginNotification(JSON.parse(data));
+        break;
+      case "fxaccounts:device_disconnected":
+        data = JSON.parse(data);
+        if (data.isLocalDevice) {
+          this._onDeviceDisconnected();
+        }
+        break;
+      case "fxaccounts:commands:open-uri":
+      case "weave:engine:clients:display-uris":
+        this._onDisplaySyncURIs(subject);
+        break;
+      case "session-save":
+        this._setPrefToSaveSession(true);
+        subject.QueryInterface(Ci.nsISupportsPRBool);
+        subject.data = true;
+        break;
+      case "places-init-complete":
+        Services.obs.removeObserver(this, "places-init-complete");
+        if (!this._migrationImportsDefaultBookmarks) {
+          this._initPlaces(false);
+        }
+        break;
+      case "idle":
+        this._backupBookmarks();
+        break;
+      case "distribution-customization-complete":
+        Services.obs.removeObserver(
+          this,
+          "distribution-customization-complete"
+        );
+        // Customization has finished, we don't need the customizer anymore.
+        delete this._distributionCustomizer;
+        break;
+      case "browser-glue-test": // used by tests
+        if (data == "force-ui-migration") {
+          this._migrateUI();
+        } else if (data == "force-distribution-customization") {
+          this._distributionCustomizer.applyCustomizations();
+          // To apply distribution bookmarks use "places-init-complete".
+        } else if (data == "force-places-init") {
+          this._initPlaces(false);
+        } else if (data == "mock-alerts-service") {
+          Object.defineProperty(this, "AlertsService", {
+            value: subject.wrappedJSObject,
+          });
+        } else if (data == "places-browser-init-complete") {
+          if (this._placesBrowserInitComplete) {
+            Services.obs.notifyObservers(null, "places-browser-init-complete");
+          }
+        } else if (data == "add-breaches-sync-handler") {
+          this._addBreachesSyncHandler();
+        }
+        break;
+      case "initial-migration-will-import-default-bookmarks":
+        this._migrationImportsDefaultBookmarks = true;
+        break;
+      case "initial-migration-did-import-default-bookmarks":
+        this._initPlaces(true);
+        break;
+      case "handle-xul-text-link":
+        let linkHandled = subject.QueryInterface(Ci.nsISupportsPRBool);
+        if (!linkHandled.data) {
+          let win = BrowserWindowTracker.getTopWindow();
+          if (win) {
+            data = JSON.parse(data);
+            let where = win.whereToOpenLink(data);
+            // Preserve legacy behavior of non-modifier left-clicks
+            // opening in a new selected tab.
+            if (where == "current") {
+              where = "tab";
+            }
+            win.openTrustedLinkIn(data.href, where);
+            linkHandled.data = true;
+          }
+        }
+        break;
+      case "profile-before-change":
+        // Any component depending on Places should be finalized in
+        // _onPlacesShutdown.  Any component that doesn't need to act after
+        // the UI has gone should be finalized in _onQuitApplicationGranted.
+        this._dispose();
+        break;
+      case "keyword-search":
+        // This notification is broadcast by the docshell when it "fixes up" a
+        // URI that it's been asked to load into a keyword search.
+        let engine = null;
+        try {
+          engine = subject.QueryInterface(Ci.nsISearchEngine);
+        } catch (ex) {
+          Cu.reportError(ex);
+        }
+        let win = BrowserWindowTracker.getTopWindow();
+        BrowserSearchTelemetry.recordSearch(
+          win.gBrowser.selectedBrowser,
+          engine,
+          "urlbar"
+        );
+        break;
+      case "browser-search-engine-modified":
+        // Ensure we cleanup the hiddenOneOffs pref when removing
+        // an engine, and that newly added engines are visible.
+        if (data == "engine-added" || data == "engine-removed") {
+          let engineName = subject.QueryInterface(Ci.nsISearchEngine).name;
+          let pref = Services.prefs.getStringPref(
+            "browser.search.hiddenOneOffs"
+          );
+          let hiddenList = pref ? pref.split(",") : [];
+          hiddenList = hiddenList.filter(x => x !== engineName);
+          Services.prefs.setStringPref(
+            "browser.search.hiddenOneOffs",
+            hiddenList.join(",")
+          );
+        }
+        break;
+      case "flash-plugin-hang":
+        this._handleFlashHang();
+        break;
+      case "xpi-signature-changed":
+        let disabledAddons = JSON.parse(data).disabled;
+        let addons = await AddonManager.getAddonsByIDs(disabledAddons);
+        if (addons.some(addon => addon)) {
+          this._notifyUnsignedAddonsDisabled();
+        }
+        break;
+      case "sync-ui-state:update":
+        this._updateFxaBadges();
+        break;
+      case "handlersvc-store-initialized":
+        // Initialize PdfJs when running in-process and remote. This only
+        // happens once since PdfJs registers global hooks. If the PdfJs
+        // extension is installed the init method below will be overridden
+        // leaving initialization to the extension.
+        // parent only: configure default prefs, set up pref observers, register
+        // pdf content handler, and initializes parent side message manager
+        // shim for privileged api access.
+        PdfJs.init(this._isNewProfile);
+
+        // Allow certain viewable internally types to be opened from downloads.
+        DownloadsViewableInternally.register();
+
+        break;
+    }
+  },
+
+  // initialization (called on application startup)
+  _init: function BG__init() {
+    let os = Services.obs;
+    os.addObserver(this, "notifications-open-settings");
+    os.addObserver(this, "final-ui-startup");
+    os.addObserver(this, "browser-delayed-startup-finished");
+    os.addObserver(this, "sessionstore-windows-restored");
+    os.addObserver(this, "browser:purge-session-history");
+    os.addObserver(this, "quit-application-requested");
+    os.addObserver(this, "quit-application-granted");
+    if (OBSERVE_LASTWINDOW_CLOSE_TOPICS) {
+      os.addObserver(this, "browser-lastwindow-close-requested");
+      os.addObserver(this, "browser-lastwindow-close-granted");
+    }
+    os.addObserver(this, "weave:service:ready");
+    os.addObserver(this, "fxaccounts:onverified");
+    os.addObserver(this, "fxaccounts:device_connected");
+    os.addObserver(this, "fxaccounts:verify_login");
+    os.addObserver(this, "fxaccounts:device_disconnected");
+    os.addObserver(this, "fxaccounts:commands:open-uri");
+    os.addObserver(this, "weave:engine:clients:display-uris");
+    os.addObserver(this, "session-save");
+    os.addObserver(this, "places-init-complete");
+    os.addObserver(this, "distribution-customization-complete");
+    os.addObserver(this, "handle-xul-text-link");
+    os.addObserver(this, "profile-before-change");
+    os.addObserver(this, "keyword-search");
+    os.addObserver(this, "browser-search-engine-modified");
+    os.addObserver(this, "restart-in-safe-mode");
+    os.addObserver(this, "flash-plugin-hang");
+    os.addObserver(this, "xpi-signature-changed");
+    os.addObserver(this, "sync-ui-state:update");
+    os.addObserver(this, "handlersvc-store-initialized");
+
+    ActorManagerParent.addJSProcessActors(JSPROCESSACTORS);
+    ActorManagerParent.addJSWindowActors(JSWINDOWACTORS);
+
+    this._flashHangCount = 0;
+    this._firstWindowReady = new Promise(
+      resolve => (this._firstWindowLoaded = resolve)
+    );
+    if (AppConstants.platform == "win") {
+      JawsScreenReaderVersionCheck.init();
+    }
+
+    // This value is to limit collecting Places telemetry once per session.
+    this._placesTelemetryGathered = false;
+  },
+
+  // cleanup (called on application shutdown)
+  _dispose: function BG__dispose() {
+    // AboutHomeStartupCache might write to the cache during
+    // quit-application-granted, so we defer uninitialization
+    // until here.
+    AboutHomeStartupCache.uninit();
+
+    let os = Services.obs;
+    os.removeObserver(this, "notifications-open-settings");
+    os.removeObserver(this, "final-ui-startup");
+    os.removeObserver(this, "sessionstore-windows-restored");
+    os.removeObserver(this, "browser:purge-session-history");
+    os.removeObserver(this, "quit-application-requested");
+    os.removeObserver(this, "quit-application-granted");
+    os.removeObserver(this, "restart-in-safe-mode");
+    if (OBSERVE_LASTWINDOW_CLOSE_TOPICS) {
+      os.removeObserver(this, "browser-lastwindow-close-requested");
+      os.removeObserver(this, "browser-lastwindow-close-granted");
+    }
+    os.removeObserver(this, "weave:service:ready");
+    os.removeObserver(this, "fxaccounts:onverified");
+    os.removeObserver(this, "fxaccounts:device_connected");
+    os.removeObserver(this, "fxaccounts:verify_login");
+    os.removeObserver(this, "fxaccounts:device_disconnected");
+    os.removeObserver(this, "fxaccounts:commands:open-uri");
+    os.removeObserver(this, "weave:engine:clients:display-uris");
+    os.removeObserver(this, "session-save");
+    if (this._bookmarksBackupIdleTime) {
+      this._userIdleService.removeIdleObserver(
+        this,
+        this._bookmarksBackupIdleTime
+      );
+      delete this._bookmarksBackupIdleTime;
+    }
+    if (this._lateTasksIdleObserver) {
+      this._userIdleService.removeIdleObserver(
+        this._lateTasksIdleObserver,
+        LATE_TASKS_IDLE_TIME_SEC
+      );
+      delete this._lateTasksIdleObserver;
+    }
+    if (this._gmpInstallManager) {
+      this._gmpInstallManager.uninit();
+      delete this._gmpInstallManager;
+    }
+    try {
+      os.removeObserver(this, "places-init-complete");
+    } catch (ex) {
+      /* Could have been removed already */
+    }
+    os.removeObserver(this, "handle-xul-text-link");
+    os.removeObserver(this, "profile-before-change");
+    os.removeObserver(this, "keyword-search");
+    os.removeObserver(this, "browser-search-engine-modified");
+    os.removeObserver(this, "flash-plugin-hang");
+    os.removeObserver(this, "xpi-signature-changed");
+    os.removeObserver(this, "sync-ui-state:update");
+
+    Services.prefs.removeObserver(
+      "privacy.trackingprotection",
+      this._matchCBCategory
+    );
+    Services.prefs.removeObserver(
+      "network.cookie.cookieBehavior",
+      this._matchCBCategory
+    );
+    Services.prefs.removeObserver(
+      ContentBlockingCategoriesPrefs.PREF_CB_CATEGORY,
+      this._updateCBCategory
+    );
+    Services.prefs.removeObserver(
+      "privacy.trackingprotection",
+      this._setPrefExpectations
+    );
+    Services.prefs.removeObserver(
+      "browser.contentblocking.features.strict",
+      this._setPrefExpectationsAndUpdate
+    );
+  },
+
+  // runs on startup, before the first command line handler is invoked
+  // (i.e. before the first window is opened)
+  _beforeUIStartup: function BG__beforeUIStartup() {
+    SessionStartup.init();
+
+    // check if we're in safe mode
+    if (Services.appinfo.inSafeMode) {
+      Services.ww.openWindow(
+        null,
+        "chrome://browser/content/safeMode.xhtml",
+        "_blank",
+        "chrome,centerscreen,modal,resizable=no",
+        null
+      );
+    }
+
+    // apply distribution customizations
+    this._distributionCustomizer.applyCustomizations();
+
+    // handle any UI migration
+    this._migrateUI();
+
+    if (!Services.prefs.prefHasUserValue(PREF_PDFJS_ISDEFAULT_CACHE_STATE)) {
+      PdfJs.checkIsDefault(this._isNewProfile);
+    }
+
+    listeners.init();
+
+    SessionStore.init();
+
+    AddonManager.maybeInstallBuiltinAddon(
+      "firefox-compact-light@mozilla.org",
+      "1.1",
+      "resource://builtin-themes/light/"
+    );
+    AddonManager.maybeInstallBuiltinAddon(
+      "firefox-compact-dark@mozilla.org",
+      "1.1",
+      "resource://builtin-themes/dark/"
+    );
+    AddonManager.maybeInstallBuiltinAddon(
+      "firefox-alpenglow@mozilla.org",
+      "1.2",
+      "resource://builtin-themes/alpenglow/"
+    );
+
+    if (AppConstants.MOZ_NORMANDY) {
+      Normandy.init();
+    }
+
+    SaveToPocket.init();
+
+    AboutHomeStartupCache.init();
+
+    Services.obs.notifyObservers(null, "browser-ui-startup-complete");
+  },
+
+  _checkForOldBuildUpdates() {
+    // check for update if our build is old
+    if (
+      AppConstants.MOZ_UPDATER &&
+      Services.prefs.getBoolPref("app.update.checkInstallTime")
+    ) {
+      let buildID = Services.appinfo.appBuildID;
+      let today = new Date().getTime();
+      /* eslint-disable no-multi-spaces */
+      let buildDate = new Date(
+        buildID.slice(0, 4), // year
+        buildID.slice(4, 6) - 1, // months are zero-based.
+        buildID.slice(6, 8), // day
+        buildID.slice(8, 10), // hour
+        buildID.slice(10, 12), // min
+        buildID.slice(12, 14)
+      ) // ms
+        .getTime();
+      /* eslint-enable no-multi-spaces */
+
+      const millisecondsIn24Hours = 86400000;
+      let acceptableAge =
+        Services.prefs.getIntPref("app.update.checkInstallTime.days") *
+        millisecondsIn24Hours;
+
+      if (buildDate + acceptableAge < today) {
+        Cc["@mozilla.org/updates/update-service;1"]
+          .getService(Ci.nsIApplicationUpdateService)
+          .checkForBackgroundUpdates();
+      }
+    }
+  },
+
+  _onSafeModeRestart: function BG_onSafeModeRestart() {
+    // prompt the user to confirm
+    let strings = gBrowserBundle;
+    let promptTitle = strings.GetStringFromName("safeModeRestartPromptTitle");
+    let promptMessage = strings.GetStringFromName(
+      "safeModeRestartPromptMessage"
+    );
+    let restartText = strings.GetStringFromName("safeModeRestartButton");
+    let buttonFlags =
+      Services.prompt.BUTTON_POS_0 * Services.prompt.BUTTON_TITLE_IS_STRING +
+      Services.prompt.BUTTON_POS_1 * Services.prompt.BUTTON_TITLE_CANCEL +
+      Services.prompt.BUTTON_POS_0_DEFAULT;
+
+    let rv = Services.prompt.confirmEx(
+      null,
+      promptTitle,
+      promptMessage,
+      buttonFlags,
+      restartText,
+      null,
+      null,
+      null,
+      {}
+    );
+    if (rv != 0) {
+      return;
+    }
+
+    let cancelQuit = Cc["@mozilla.org/supports-PRBool;1"].createInstance(
+      Ci.nsISupportsPRBool
+    );
+    Services.obs.notifyObservers(
+      cancelQuit,
+      "quit-application-requested",
+      "restart"
+    );
+
+    if (!cancelQuit.data) {
+      Services.startup.restartInSafeMode(Ci.nsIAppStartup.eAttemptQuit);
+    }
+  },
+
+  _trackSlowStartup() {
+    let disabled = Services.prefs.getBoolPref(
+      "browser.slowStartup.notificationDisabled"
+    );
+
+    Services.telemetry.scalarSet(
+      "browser.startup.slow_startup_notification_disabled",
+      disabled
+    );
+
+    if (Services.startup.interrupted || disabled) {
+      return;
+    }
+
+    let currentTime = Math.round(Cu.now());
+
+    Services.telemetry.scalarSet("browser.startup.recorded_time", currentTime);
+
+    let averageTime = 0;
+    let samples = 0;
+    try {
+      averageTime = Services.prefs.getIntPref(
+        "browser.slowStartup.averageTime"
+      );
+      samples = Services.prefs.getIntPref("browser.slowStartup.samples");
+    } catch (e) {}
+
+    let totalTime = averageTime * samples + currentTime;
+    samples++;
+    averageTime = totalTime / samples;
+
+    Services.telemetry.scalarSet("browser.startup.average_time", averageTime);
+    Services.telemetry.scalarSet(
+      "browser.startup.slow_startup_notified",
+      false
+    );
+    Services.telemetry.scalarSet(
+      "browser.startup.too_new_for_notification",
+      false
+    );
+
+    if (
+      samples >= Services.prefs.getIntPref("browser.slowStartup.maxSamples")
+    ) {
+      if (
+        averageTime >
+        Services.prefs.getIntPref("browser.slowStartup.timeThreshold")
+      ) {
+        this._calculateProfileAgeInDays().then(
+          this._showSlowStartupNotification,
+          null
+        );
+      }
+      averageTime = 0;
+      samples = 0;
+    }
+
+    Services.prefs.setIntPref("browser.slowStartup.averageTime", averageTime);
+    Services.prefs.setIntPref("browser.slowStartup.samples", samples);
+  },
+
+  async _calculateProfileAgeInDays() {
+    let ProfileAge = ChromeUtils.import(
+      "resource://gre/modules/ProfileAge.jsm",
+      {}
+    ).ProfileAge;
+    let profileAge = await ProfileAge();
+
+    let creationDate = await profileAge.created;
+    let resetDate = await profileAge.reset;
+
+    // if the profile was reset, consider the
+    // reset date for its age.
+    let profileDate = resetDate || creationDate;
+
+    const ONE_DAY = 24 * 60 * 60 * 1000;
+    return (Date.now() - profileDate) / ONE_DAY;
+  },
+
+  _showSlowStartupNotification(profileAge) {
+    if (profileAge < 90) {
+      // 3 months
+      Services.telemetry.scalarSet(
+        "browser.startup.too_new_for_notification",
+        true
+      );
+      return;
+    }
+
+    let win = BrowserWindowTracker.getTopWindow();
+    if (!win) {
+      return;
+    }
+
+    Services.telemetry.scalarSet("browser.startup.slow_startup_notified", true);
+
+    const NO_ACTION = 0;
+    const OPENED_SUMO = 1;
+    const NEVER_SHOW_AGAIN = 2;
+    const DISMISS_NOTIFICATION = 3;
+
+    Services.telemetry.scalarSet("browser.startup.action", NO_ACTION);
+
+    let productName = gBrandBundle.GetStringFromName("brandFullName");
+    let message = win.gNavigatorBundle.getFormattedString(
+      "slowStartup.message",
+      [productName]
+    );
+
+    let buttons = [
+      {
+        label: win.gNavigatorBundle.getString("slowStartup.helpButton.label"),
+        accessKey: win.gNavigatorBundle.getString(
+          "slowStartup.helpButton.accesskey"
+        ),
+        callback() {
+          Services.telemetry.scalarSet("browser.startup.action", OPENED_SUMO);
+          win.openTrustedLinkIn(
+            "https://support.mozilla.org/kb/reset-firefox-easily-fix-most-problems",
+            "tab"
+          );
+        },
+      },
+      {
+        label: win.gNavigatorBundle.getString(
+          "slowStartup.disableNotificationButton.label"
+        ),
+        accessKey: win.gNavigatorBundle.getString(
+          "slowStartup.disableNotificationButton.accesskey"
+        ),
+        callback() {
+          Services.telemetry.scalarSet(
+            "browser.startup.action",
+            NEVER_SHOW_AGAIN
+          );
+          Services.prefs.setBoolPref(
+            "browser.slowStartup.notificationDisabled",
+            true
+          );
+        },
+      },
+    ];
+
+    let closeCallback = closeType => {
+      if (closeType == "dismissed") {
+        Services.telemetry.scalarSet(
+          "browser.startup.action",
+          DISMISS_NOTIFICATION
+        );
+      }
+    };
+
+    win.gNotificationBox.appendNotification(
+      message,
+      "slow-startup",
+      "chrome://browser/skin/slowStartup-16.png",
+      win.gNotificationBox.PRIORITY_INFO_LOW,
+      buttons,
+      closeCallback
+    );
+  },
+
+  /**
+   * Show a notification bar offering a reset.
+   *
+   * @param reason
+   *        String of either "unused" or "uninstall", specifying the reason
+   *        why a profile reset is offered.
+   */
+  _resetProfileNotification(reason) {
+    let win = BrowserWindowTracker.getTopWindow();
+    if (!win) {
+      return;
+    }
+
+    const { ResetProfile } = ChromeUtils.import(
+      "resource://gre/modules/ResetProfile.jsm"
+    );
+    if (!ResetProfile.resetSupported()) {
+      return;
+    }
+
+    let productName = gBrandBundle.GetStringFromName("brandShortName");
+    let resetBundle = Services.strings.createBundle(
+      "chrome://global/locale/resetProfile.properties"
+    );
+
+    let message;
+    if (reason == "unused") {
+      message = resetBundle.formatStringFromName("resetUnusedProfile.message", [
+        productName,
+      ]);
+    } else if (reason == "uninstall") {
+      message = resetBundle.formatStringFromName("resetUninstalled.message", [
+        productName,
+      ]);
+    } else {
+      throw new Error(
+        `Unknown reason (${reason}) given to _resetProfileNotification.`
+      );
+    }
+    let buttons = [
+      {
+        label: resetBundle.formatStringFromName(
+          "refreshProfile.resetButton.label",
+          [productName]
+        ),
+        accessKey: resetBundle.GetStringFromName(
+          "refreshProfile.resetButton.accesskey"
+        ),
+        callback() {
+          ResetProfile.openConfirmationDialog(win);
+        },
+      },
+    ];
+
+    win.gNotificationBox.appendNotification(
+      message,
+      "reset-profile-notification",
+      "chrome://global/skin/icons/question-64.png",
+      win.gNotificationBox.PRIORITY_INFO_LOW,
+      buttons
+    );
+  },
+
+  _notifyUnsignedAddonsDisabled() {
+    let win = BrowserWindowTracker.getTopWindow();
+    if (!win) {
+      return;
+    }
+
+    let message = win.gNavigatorBundle.getString(
+      "unsignedAddonsDisabled.message"
+    );
+    let buttons = [
+      {
+        label: win.gNavigatorBundle.getString(
+          "unsignedAddonsDisabled.learnMore.label"
+        ),
+        accessKey: win.gNavigatorBundle.getString(
+          "unsignedAddonsDisabled.learnMore.accesskey"
+        ),
+        callback() {
+          win.BrowserOpenAddonsMgr("addons://list/extension?unsigned=true");
+        },
+      },
+    ];
+
+    win.gHighPriorityNotificationBox.appendNotification(
+      message,
+      "unsigned-addons-disabled",
+      "",
+      win.gHighPriorityNotificationBox.PRIORITY_WARNING_MEDIUM,
+      buttons
+    );
+  },
+
+  _firstWindowTelemetry(aWindow) {
+    let scaling = aWindow.devicePixelRatio * 100;
+    try {
+      Services.telemetry.getHistogramById("DISPLAY_SCALING").add(scaling);
+    } catch (ex) {}
+  },
+
+  _collectStartupConditionsTelemetry() {
+    let nowSeconds = Math.round(Date.now() / 1000);
+    // Don't include cases where we don't have the pref. This rules out the first install
+    // as well as the first run of a build since this was introduced. These could by some
+    // definitions be referred to as "cold" startups, but probably not since we likely
+    // just wrote many of the files we use to disk. This way we should approximate a lower
+    // bound to the number of cold startups rather than an upper bound.
+    let lastCheckSeconds = Services.prefs.getIntPref(
+      "browser.startup.lastColdStartupCheck",
+      nowSeconds
+    );
+    Services.prefs.setIntPref(
+      "browser.startup.lastColdStartupCheck",
+      nowSeconds
+    );
+    try {
+      let secondsSinceLastOSRestart =
+        Services.startup.secondsSinceLastOSRestart;
+      let isColdStartup =
+        nowSeconds - secondsSinceLastOSRestart > lastCheckSeconds;
+      Services.telemetry.scalarSet("startup.is_cold", isColdStartup);
+      Services.telemetry.scalarSet(
+        "startup.seconds_since_last_os_restart",
+        secondsSinceLastOSRestart
+      );
+    } catch (ex) {
+      Cu.reportError(ex);
+    }
+  },
+
+  _collectFirstPartyIsolationTelemetry() {
+    let update = aIsFirstPartyIsolated => {
+      Services.telemetry.scalarSet(
+        "privacy.feature.first_party_isolation_enabled",
+        aIsFirstPartyIsolated
+      );
+    };
+
+    XPCOMUtils.defineLazyPreferenceGetter(
+      this,
+      "_firstPartyIsolated",
+      "privacy.firstparty.isolate",
+      false,
+      (_data, _previous, latest) => {
+        update(latest);
+      }
+    );
+    update(this._firstPartyIsolated);
+  },
+
+  // the first browser window has finished initializing
+  _onFirstWindowLoaded: function BG__onFirstWindowLoaded(aWindow) {
+    AboutNewTab.init();
+
+    TabCrashHandler.init();
+
+    ProcessHangMonitor.init();
+
+    // A channel for "remote troubleshooting" code...
+    let channel = new WebChannel(
+      "remote-troubleshooting",
+      "remote-troubleshooting"
+    );
+    channel.listen((id, data, target) => {
+      if (data.command == "request") {
+        let { Troubleshoot } = ChromeUtils.import(
+          "resource://gre/modules/Troubleshoot.jsm"
+        );
+        Troubleshoot.snapshot(snapshotData => {
+          // for privacy we remove crash IDs and all preferences (but bug 1091944
+          // exists to expose prefs once we are confident of privacy implications)
+          delete snapshotData.crashes;
+          delete snapshotData.modifiedPreferences;
+          delete snapshotData.printingPreferences;
+          channel.send(snapshotData, target);
+        });
+      }
+    });
+
+    this._trackSlowStartup();
+
+    // Offer to reset a user's profile if it hasn't been used for 60 days.
+    const OFFER_PROFILE_RESET_INTERVAL_MS = 60 * 24 * 60 * 60 * 1000;
+    let lastUse = Services.appinfo.replacedLockTime;
+    let disableResetPrompt = Services.prefs.getBoolPref(
+      "browser.disableResetPrompt",
+      false
+    );
+
+    if (
+      !disableResetPrompt &&
+      lastUse &&
+      Date.now() - lastUse >= OFFER_PROFILE_RESET_INTERVAL_MS
+    ) {
+      this._resetProfileNotification("unused");
+    } else if (AppConstants.platform == "win" && !disableResetPrompt) {
+      // Check if we were just re-installed and offer Firefox Reset
+      let updateChannel;
+      try {
+        updateChannel = ChromeUtils.import(
+          "resource://gre/modules/UpdateUtils.jsm",
+          {}
+        ).UpdateUtils.UpdateChannel;
+      } catch (ex) {}
+      if (updateChannel) {
+        let uninstalledValue = WindowsRegistry.readRegKey(
+          Ci.nsIWindowsRegKey.ROOT_KEY_CURRENT_USER,
+          "Software\\Mozilla\\Firefox",
+          `Uninstalled-${updateChannel}`
+        );
+        let removalSuccessful = WindowsRegistry.removeRegKey(
+          Ci.nsIWindowsRegKey.ROOT_KEY_CURRENT_USER,
+          "Software\\Mozilla\\Firefox",
+          `Uninstalled-${updateChannel}`
+        );
+        if (removalSuccessful && uninstalledValue == "True") {
+          this._resetProfileNotification("uninstall");
+        }
+      }
+    }
+
+    this._checkForOldBuildUpdates();
+
+    // Check if Sync is configured
+    if (Services.prefs.prefHasUserValue("services.sync.username")) {
+      WeaveService.init();
+    }
+
+    PageThumbs.init();
+
+    NewTabUtils.init();
+
+    Services.telemetry.setEventRecordingEnabled(
+      "security.ui.protections",
+      true
+    );
+
+    PageActions.init();
+
+    DoHController.init();
+
+    this._firstWindowTelemetry(aWindow);
+    this._firstWindowLoaded();
+
+    this._collectStartupConditionsTelemetry();
+
+    this._collectFirstPartyIsolationTelemetry();
+
+    if (!this._placesTelemetryGathered && TelemetryUtils.isTelemetryEnabled) {
+      this._placesTelemetryGathered = true;
+      // Collect Places telemetry on the first idle.
+      Services.tm.idleDispatchToMainThread(() => {
+        PlacesDBUtils.telemetry();
+      });
+    }
+
+    // Set the default favicon size for UI views that use the page-icon protocol.
+    PlacesUtils.favicons.setDefaultIconURIPreferredSize(
+      16 * aWindow.devicePixelRatio
+    );
+    this._setPrefExpectationsAndUpdate();
+    this._matchCBCategory();
+
+    // This observes the entire privacy.trackingprotection.* pref tree.
+    Services.prefs.addObserver(
+      "privacy.trackingprotection",
+      this._matchCBCategory
+    );
+    Services.prefs.addObserver(
+      "network.cookie.cookieBehavior",
+      this._matchCBCategory
+    );
+    Services.prefs.addObserver(
+      ContentBlockingCategoriesPrefs.PREF_CB_CATEGORY,
+      this._updateCBCategory
+    );
+    Services.prefs.addObserver(
+      "media.autoplay.default",
+      this._updateAutoplayPref
+    );
+    Services.prefs.addObserver(
+      "media.hardwaremediakeys.enabled",
+      this._updateMediaControlPref
+    );
+    Services.prefs.addObserver(
+      "privacy.trackingprotection",
+      this._setPrefExpectations
+    );
+    Services.prefs.addObserver(
+      "browser.contentblocking.features.strict",
+      this._setPrefExpectationsAndUpdate
+    );
+  },
+
+  _updateAutoplayPref() {
+    const blocked = Services.prefs.getIntPref("media.autoplay.default", 1);
+    const telemetry = Services.telemetry.getHistogramById(
+      "AUTOPLAY_DEFAULT_SETTING_CHANGE"
+    );
+    const labels = { 0: "allow", 1: "blockAudible", 5: "blockAll" };
+    if (blocked in labels) {
+      telemetry.add(labels[blocked]);
+    }
+  },
+
+  _updateMediaControlPref() {
+    const enabled = Services.prefs.getBoolPref(
+      "media.hardwaremediakeys.enabled"
+    );
+    const telemetry = Services.telemetry.getHistogramById(
+      "MEDIA_CONTROL_SETTING_CHANGE"
+    );
+    telemetry.add(enabled ? "EnableTotal" : "DisableTotal");
+  },
+
+  _setPrefExpectations() {
+    ContentBlockingCategoriesPrefs.setPrefExpectations();
+  },
+
+  _setPrefExpectationsAndUpdate() {
+    ContentBlockingCategoriesPrefs.setPrefExpectations();
+    ContentBlockingCategoriesPrefs.updateCBCategory();
+  },
+
+  _matchCBCategory() {
+    ContentBlockingCategoriesPrefs.matchCBCategory();
+  },
+
+  _updateCBCategory() {
+    ContentBlockingCategoriesPrefs.updateCBCategory();
+  },
+
+  _recordContentBlockingTelemetry() {
+    Services.telemetry.setEventRecordingEnabled(
+      "security.ui.protectionspopup",
+      Services.prefs.getBoolPref(
+        "security.protectionspopup.recordEventTelemetry"
+      )
+    );
+    Services.telemetry.setEventRecordingEnabled(
+      "security.ui.app_menu",
+      Services.prefs.getBoolPref("security.app_menu.recordEventTelemetry")
+    );
+
+    let tpEnabled = Services.prefs.getBoolPref(
+      "privacy.trackingprotection.enabled"
+    );
+    Services.telemetry
+      .getHistogramById("TRACKING_PROTECTION_ENABLED")
+      .add(tpEnabled);
+
+    let tpPBDisabled = Services.prefs.getBoolPref(
+      "privacy.trackingprotection.pbmode.enabled"
+    );
+    Services.telemetry
+      .getHistogramById("TRACKING_PROTECTION_PBM_DISABLED")
+      .add(!tpPBDisabled);
+
+    let cookieBehavior = Services.prefs.getIntPref(
+      "network.cookie.cookieBehavior"
+    );
+    Services.telemetry.getHistogramById("COOKIE_BEHAVIOR").add(cookieBehavior);
+
+    let fpEnabled = Services.prefs.getBoolPref(
+      "privacy.trackingprotection.fingerprinting.enabled"
+    );
+    let cmEnabled = Services.prefs.getBoolPref(
+      "privacy.trackingprotection.cryptomining.enabled"
+    );
+    let categoryPref;
+    switch (
+      Services.prefs.getStringPref("browser.contentblocking.category", null)
+    ) {
+      case "standard":
+        categoryPref = 0;
+        break;
+      case "strict":
+        categoryPref = 1;
+        break;
+      case "custom":
+        categoryPref = 2;
+        break;
+      default:
+        // Any other value is unsupported.
+        categoryPref = 3;
+        break;
+    }
+
+    Services.telemetry.scalarSet(
+      "contentblocking.fingerprinting_blocking_enabled",
+      fpEnabled
+    );
+    Services.telemetry.scalarSet(
+      "contentblocking.cryptomining_blocking_enabled",
+      cmEnabled
+    );
+    Services.telemetry.scalarSet("contentblocking.category", categoryPref);
+  },
+
+  _recordDataSanitizationPrefs() {
+    Services.telemetry.scalarSet(
+      "datasanitization.network_cookie_lifetimePolicy",
+      Services.prefs.getIntPref("network.cookie.lifetimePolicy")
+    );
+    Services.telemetry.scalarSet(
+      "datasanitization.privacy_sanitize_sanitizeOnShutdown",
+      Services.prefs.getBoolPref("privacy.sanitize.sanitizeOnShutdown")
+    );
+    Services.telemetry.scalarSet(
+      "datasanitization.privacy_clearOnShutdown_cookies",
+      Services.prefs.getBoolPref("privacy.clearOnShutdown.cookies")
+    );
+    Services.telemetry.scalarSet(
+      "datasanitization.privacy_clearOnShutdown_history",
+      Services.prefs.getBoolPref("privacy.clearOnShutdown.history")
+    );
+    Services.telemetry.scalarSet(
+      "datasanitization.privacy_clearOnShutdown_formdata",
+      Services.prefs.getBoolPref("privacy.clearOnShutdown.formdata")
+    );
+    Services.telemetry.scalarSet(
+      "datasanitization.privacy_clearOnShutdown_downloads",
+      Services.prefs.getBoolPref("privacy.clearOnShutdown.downloads")
+    );
+    Services.telemetry.scalarSet(
+      "datasanitization.privacy_clearOnShutdown_cache",
+      Services.prefs.getBoolPref("privacy.clearOnShutdown.cache")
+    );
+    Services.telemetry.scalarSet(
+      "datasanitization.privacy_clearOnShutdown_sessions",
+      Services.prefs.getBoolPref("privacy.clearOnShutdown.sessions")
+    );
+    Services.telemetry.scalarSet(
+      "datasanitization.privacy_clearOnShutdown_offlineApps",
+      Services.prefs.getBoolPref("privacy.clearOnShutdown.offlineApps")
+    );
+    Services.telemetry.scalarSet(
+      "datasanitization.privacy_clearOnShutdown_siteSettings",
+      Services.prefs.getBoolPref("privacy.clearOnShutdown.siteSettings")
+    );
+    Services.telemetry.scalarSet(
+      "datasanitization.privacy_clearOnShutdown_openWindows",
+      Services.prefs.getBoolPref("privacy.clearOnShutdown.openWindows")
+    );
+
+    let exceptions = 0;
+    for (let permission of Services.perms.all) {
+      // We consider just permissions set for http, https and file URLs.
+      if (
+        permission.type == "cookie" &&
+        permission.capability == Ci.nsICookiePermission.ACCESS_SESSION &&
+        ["http", "https", "file"].some(scheme =>
+          permission.principal.schemeIs(scheme)
+        )
+      ) {
+        exceptions++;
+      }
+    }
+    Services.telemetry.scalarSet(
+      "datasanitization.session_permission_exceptions",
+      exceptions
+    );
+  },
+
+  _sendMediaTelemetry() {
+    let win = Services.wm.getMostRecentWindow("navigator:browser");
+    if (win) {
+      let v = win.document.createElementNS(
+        "http://www.w3.org/1999/xhtml",
+        "video"
+      );
+      v.reportCanPlayTelemetry();
+    }
+  },
+
+  /**
+   * Application shutdown handler.
+   */
+  _onQuitApplicationGranted() {
+    // This pref must be set here because SessionStore will use its value
+    // on quit-application.
+    this._setPrefToSaveSession();
+
+    // Call trackStartupCrashEnd here in case the delayed call on startup hasn't
+    // yet occurred (see trackStartupCrashEnd caller in browser.js).
+    try {
+      Services.startup.trackStartupCrashEnd();
+    } catch (e) {
+      Cu.reportError(
+        "Could not end startup crash tracking in quit-application-granted: " + e
+      );
+    }
+
+    if (this._bookmarksBackupIdleTime) {
+      this._userIdleService.removeIdleObserver(
+        this,
+        this._bookmarksBackupIdleTime
+      );
+      delete this._bookmarksBackupIdleTime;
+    }
+
+    for (let mod of Object.values(initializedModules)) {
+      if (mod.uninit) {
+        mod.uninit();
+      }
+    }
+
+    BrowserUsageTelemetry.uninit();
+    SearchSERPTelemetry.uninit();
+    PageThumbs.uninit();
+    NewTabUtils.uninit();
+
+    Normandy.uninit();
+    RFPHelper.uninit();
+    ASRouterNewTabHook.destroy();
+  },
+
+  // Set up a listener to enable/disable the screenshots extension
+  // based on its preference.
+  _monitorScreenshotsPref() {
+    const PREF = "extensions.screenshots.disabled";
+    const ID = "screenshots@mozilla.org";
+    const _checkScreenshotsPref = async () => {
+      let addon = await AddonManager.getAddonByID(ID);
+      let disabled = Services.prefs.getBoolPref(PREF, false);
+      if (disabled) {
+        await addon.disable({ allowSystemAddons: true });
+      } else {
+        await addon.enable({ allowSystemAddons: true });
+      }
+    };
+    Services.prefs.addObserver(PREF, _checkScreenshotsPref);
+    _checkScreenshotsPref();
+  },
+
+  _monitorWebcompatReporterPref() {
+    const PREF = "extensions.webcompat-reporter.enabled";
+    const ID = "webcompat-reporter@mozilla.org";
+    Services.prefs.addObserver(PREF, async () => {
+      let addon = await AddonManager.getAddonByID(ID);
+      let enabled = Services.prefs.getBoolPref(PREF, false);
+      if (enabled && !addon.isActive) {
+        await addon.enable({ allowSystemAddons: true });
+      } else if (!enabled && addon.isActive) {
+        await addon.disable({ allowSystemAddons: true });
+      }
+    });
+  },
+
+  _monitorHTTPSOnlyPref() {
+    const PREF_ENABLED = "dom.security.https_only_mode";
+    const PREF_WAS_ENABLED = "dom.security.https_only_mode_ever_enabled";
+    const _checkHTTPSOnlyPref = async () => {
+      const enabled = Services.prefs.getBoolPref(PREF_ENABLED, false);
+      const was_enabled = Services.prefs.getBoolPref(PREF_WAS_ENABLED, false);
+      let value = 0;
+      if (enabled) {
+        value = 1;
+        Services.prefs.setBoolPref(PREF_WAS_ENABLED, true);
+      } else if (was_enabled) {
+        value = 2;
+      }
+      Services.telemetry.scalarSet("security.https_only_mode_enabled", value);
+    };
+
+    Services.prefs.addObserver(PREF_ENABLED, _checkHTTPSOnlyPref);
+    _checkHTTPSOnlyPref();
+
+    const PREF_PBM_WAS_ENABLED =
+      "dom.security.https_only_mode_ever_enabled_pbm";
+    const PREF_PBM_ENABLED = "dom.security.https_only_mode_pbm";
+
+    const _checkHTTPSOnlyPBMPref = async () => {
+      const enabledPBM = Services.prefs.getBoolPref(PREF_PBM_ENABLED, false);
+      const was_enabledPBM = Services.prefs.getBoolPref(
+        PREF_PBM_WAS_ENABLED,
+        false
+      );
+      let valuePBM = 0;
+      if (enabledPBM) {
+        valuePBM = 1;
+        Services.prefs.setBoolPref(PREF_PBM_WAS_ENABLED, true);
+      } else if (was_enabledPBM) {
+        valuePBM = 2;
+      }
+      Services.telemetry.scalarSet(
+        "security.https_only_mode_enabled_pbm",
+        valuePBM
+      );
+    };
+
+    Services.prefs.addObserver(PREF_PBM_ENABLED, _checkHTTPSOnlyPBMPref);
+    _checkHTTPSOnlyPBMPref();
+  },
+
+  _monitorIonPref() {
+    const PREF_ION_ID = "toolkit.telemetry.pioneerId";
+
+    const _checkIonPref = async () => {
+      for (let win of Services.wm.getEnumerator("navigator:browser")) {
+        win.document.getElementById(
+          "ion-button"
+        ).hidden = !Services.prefs.getStringPref(PREF_ION_ID, null);
+      }
+    };
+
+    const windowListener = {
+      onOpenWindow(xulWindow) {
+        const win = xulWindow.docShell.domWindow;
+        win.addEventListener("load", () => {
+          const ionButton = win.document.getElementById("ion-button");
+          if (ionButton) {
+            ionButton.hidden = !Services.prefs.getStringPref(PREF_ION_ID, null);
+          }
+        });
+      },
+      onCloseWindow() {},
+    };
+
+    Services.prefs.addObserver(PREF_ION_ID, _checkIonPref);
+    Services.wm.addListener(windowListener);
+    _checkIonPref();
+  },
+
+  _monitorIonStudies() {
+    const STUDY_ADDON_COLLECTION_KEY = "pioneer-study-addons-v1";
+    const PREF_ION_NEW_STUDIES_AVAILABLE =
+      "toolkit.telemetry.pioneer-new-studies-available";
+
+    const _badgeIcon = async () => {
+      for (let win of Services.wm.getEnumerator("navigator:browser")) {
+        win.document
+          .getElementById("ion-button")
+          .querySelector(".toolbarbutton-badge")
+          .classList.add("feature-callout");
+      }
+    };
+
+    const windowListener = {
+      onOpenWindow(xulWindow) {
+        const win = xulWindow.docShell.domWindow;
+        win.addEventListener("load", () => {
+          const ionButton = win.document.getElementById("ion-button");
+          if (ionButton) {
+            const badge = ionButton.querySelector(".toolbarbutton-badge");
+            if (
+              Services.prefs.getBoolPref(PREF_ION_NEW_STUDIES_AVAILABLE, false)
+            ) {
+              badge.classList.add("feature-callout");
+            } else {
+              badge.classList.remove("feature-callout");
+            }
+          }
+        });
+      },
+      onCloseWindow() {},
+    };
+
+    // Update all open windows if the pref changes.
+    Services.prefs.addObserver(PREF_ION_NEW_STUDIES_AVAILABLE, _badgeIcon);
+
+    // Badge any currently-open windows.
+    if (Services.prefs.getBoolPref(PREF_ION_NEW_STUDIES_AVAILABLE, false)) {
+      _badgeIcon();
+    }
+
+    RemoteSettings(STUDY_ADDON_COLLECTION_KEY).on("sync", async event => {
+      Services.prefs.setBoolPref(PREF_ION_NEW_STUDIES_AVAILABLE, true);
+    });
+
+    // When a new window opens, check if we need to badge the icon.
+    Services.wm.addListener(windowListener);
+  },
+
+  _showNewInstallModal() {
+    // Allow other observers of the same topic to run while we open the dialog.
+    Services.tm.dispatchToMainThread(() => {
+      let win = BrowserWindowTracker.getTopWindow();
+
+      let stack = win.gBrowser.getPanel().querySelector(".browserStack");
+      let mask = win.document.createXULElement("box");
+      mask.setAttribute("id", "content-mask");
+      stack.appendChild(mask);
+
+      Services.ww.openWindow(
+        win,
+        "chrome://browser/content/newInstall.xhtml",
+        "_blank",
+        "chrome,modal,resizable=no,centerscreen",
+        null
+      );
+      mask.remove();
+    });
+  },
+
+  // All initial windows have opened.
+  _onWindowsRestored: function BG__onWindowsRestored() {
+    if (this._windowsWereRestored) {
+      return;
+    }
+    this._windowsWereRestored = true;
+
+    BrowserUsageTelemetry.init();
+    SearchSERPTelemetry.init();
+
+    ExtensionsUI.init();
+
+    let signingRequired;
+    if (AppConstants.MOZ_REQUIRE_SIGNING) {
+      signingRequired = true;
+    } else {
+      signingRequired = Services.prefs.getBoolPref(
+        "xpinstall.signatures.required"
+      );
+    }
+
+    if (signingRequired) {
+      let disabledAddons = AddonManager.getStartupChanges(
+        AddonManager.STARTUP_CHANGE_DISABLED
+      );
+      AddonManager.getAddonsByIDs(disabledAddons).then(addons => {
+        for (let addon of addons) {
+          if (addon.signedState <= AddonManager.SIGNEDSTATE_MISSING) {
+            this._notifyUnsignedAddonsDisabled();
+            break;
+          }
+        }
+      });
+    }
+
+    if (AppConstants.MOZ_CRASHREPORTER) {
+      UnsubmittedCrashHandler.init();
+      UnsubmittedCrashHandler.scheduleCheckForUnsubmittedCrashReports();
+      FeatureGate.annotateCrashReporter();
+      FeatureGate.observePrefChangesForCrashReportAnnotation();
+    }
+
+    if (AppConstants.ASAN_REPORTER) {
+      var { AsanReporter } = ChromeUtils.import(
+        "resource:///modules/AsanReporter.jsm"
+      );
+      AsanReporter.init();
+    }
+
+    Sanitizer.onStartup();
+    this._scheduleStartupIdleTasks();
+    this._lateTasksIdleObserver = (idleService, topic, data) => {
+      if (topic == "idle") {
+        idleService.removeIdleObserver(
+          this._lateTasksIdleObserver,
+          LATE_TASKS_IDLE_TIME_SEC
+        );
+        delete this._lateTasksIdleObserver;
+        this._scheduleBestEffortUserIdleTasks();
+      }
+    };
+    this._userIdleService.addIdleObserver(
+      this._lateTasksIdleObserver,
+      LATE_TASKS_IDLE_TIME_SEC
+    );
+
+    this._monitorScreenshotsPref();
+    this._monitorWebcompatReporterPref();
+    this._monitorHTTPSOnlyPref();
+    this._monitorIonPref();
+    this._monitorIonStudies();
+
+    let pService = Cc["@mozilla.org/toolkit/profile-service;1"].getService(
+      Ci.nsIToolkitProfileService
+    );
+    if (pService.createdAlternateProfile) {
+      this._showNewInstallModal();
+    }
+
+    FirefoxMonitor.init();
+  },
+
+  /**
+   * Use this function as an entry point to schedule tasks that
+   * need to run only once after startup, and can be scheduled
+   * by using an idle callback.
+   *
+   * The functions scheduled here will fire from idle callbacks
+   * once every window has finished being restored by session
+   * restore, and it's guaranteed that they will run before
+   * the equivalent per-window idle tasks
+   * (from _schedulePerWindowIdleTasks in browser.js).
+   *
+   * If you have something that can wait even further than the
+   * per-window initialization, and is okay with not being run in some
+   * sessions, please schedule them using
+   * _scheduleBestEffortUserIdleTasks.
+   * Don't be fooled by thinking that the use of the timeout parameter
+   * will delay your function: it will just ensure that it potentially
+   * happens _earlier_ than expected (when the timeout limit has been reached),
+   * but it will not make it happen later (and out of order) compared
+   * to the other ones scheduled together.
+   */
+  _scheduleStartupIdleTasks() {
+    const idleTasks = [
+      // It's important that SafeBrowsing is initialized reasonably
+      // early, so we use a maximum timeout for it.
+      {
+        task: () => {
+          SafeBrowsing.init();
+        },
+        timeout: 5000,
+      },
+
+      {
+        task: async () => {
+          await ContextualIdentityService.load();
+          Discovery.update();
+        },
+      },
+
+      {
+        task: () => {
+          // We postponed loading bookmarks toolbar content until startup
+          // has finished, so we can start loading it now:
+          PlacesUIUtils.unblockToolbars();
+        },
+      },
+
+      // Begin listening for incoming push messages.
+      {
+        task: () => {
+          try {
+            PushService.wrappedJSObject.ensureReady();
+          } catch (ex) {
+            // NS_ERROR_NOT_AVAILABLE will get thrown for the PushService
+            // getter if the PushService is disabled.
+            if (ex.result != Cr.NS_ERROR_NOT_AVAILABLE) {
+              throw ex;
+            }
+          }
+        },
+      },
+
+      {
+        task: () => {
+          this._recordContentBlockingTelemetry();
+        },
+      },
+
+      {
+        task: () => {
+          this._recordDataSanitizationPrefs();
+        },
+      },
+
+      {
+        task: () => {
+          let enableCertErrorUITelemetry = Services.prefs.getBoolPref(
+            "security.certerrors.recordEventTelemetry",
+            true
+          );
+          Services.telemetry.setEventRecordingEnabled(
+            "security.ui.certerror",
+            enableCertErrorUITelemetry
+          );
+        },
+      },
+
+      // Load the Login Manager data from disk off the main thread, some time
+      // after startup.  If the data is required before this runs, for example
+      // because a restored page contains a password field, it will be loaded on
+      // the main thread, and this initialization request will be ignored.
+      {
+        task: () => {
+          try {
+            Services.logins;
+          } catch (ex) {
+            Cu.reportError(ex);
+          }
+        },
+        timeout: 3000,
+      },
+
+      // Add breach alerts pref observer reasonably early so the pref flip works
+      {
+        task: () => {
+          this._addBreachAlertsPrefObserver();
+        },
+      },
+
+      {
+        condition: AppConstants.platform == "win",
+        task: () => {
+          // For Windows 7, initialize the jump list module.
+          const WINTASKBAR_CONTRACTID = "@mozilla.org/windows-taskbar;1";
+          if (
+            WINTASKBAR_CONTRACTID in Cc &&
+            Cc[WINTASKBAR_CONTRACTID].getService(Ci.nsIWinTaskbar).available
+          ) {
+            let temp = {};
+            ChromeUtils.import(
+              "resource:///modules/WindowsJumpLists.jsm",
+              temp
+            );
+            temp.WinTaskbarJumpList.startup();
+          }
+        },
+      },
+
+      {
+        task: () => {
+          this._maybeShowDefaultBrowserPrompt();
+        },
+      },
+
+      {
+        task: () => {
+          let { setTimeout } = ChromeUtils.import(
+            "resource://gre/modules/Timer.jsm"
+          );
+          setTimeout(function() {
+            Services.tm.idleDispatchToMainThread(
+              Services.startup.trackStartupCrashEnd
+            );
+          }, STARTUP_CRASHES_END_DELAY_MS);
+        },
+      },
+
+      {
+        task: () => {
+          let handlerService = Cc[
+            "@mozilla.org/uriloader/handler-service;1"
+          ].getService(Ci.nsIHandlerService);
+          handlerService.asyncInit();
+        },
+      },
+
+      {
+        condition: AppConstants.platform == "win",
+        task: () => {
+          JawsScreenReaderVersionCheck.onWindowsRestored();
+        },
+      },
+
+      {
+        task: () => {
+          RFPHelper.init();
+        },
+      },
+
+      {
+        task: () => {
+          Blocklist.loadBlocklistAsync();
+        },
+      },
+
+      {
+        task: () => {
+          TabUnloader.init();
+        },
+      },
+
+      // request startup of Chromium remote debugging protocol
+      // (observer will only be notified when --remote-debugging-port is passed)
+      {
+        condition: AppConstants.ENABLE_REMOTE_AGENT,
+        task: () => {
+          Services.obs.notifyObservers(null, "remote-startup-requested");
+        },
+      },
+
+      // Run TRR performance measurements for DoH.
+      {
+        task: () => {
+          let enabledPref = "doh-rollout.trrRace.enabled";
+          let completePref = "doh-rollout.trrRace.complete";
+
+          if (Services.prefs.getBoolPref(enabledPref, false)) {
+            if (!Services.prefs.getBoolPref(completePref, false)) {
+              new TRRRacer().run(() => {
+                Services.prefs.setBoolPref(completePref, true);
+              });
+            }
+          } else {
+            Services.prefs.addObserver(enabledPref, function observer() {
+              if (Services.prefs.getBoolPref(enabledPref, false)) {
+                Services.prefs.removeObserver(enabledPref, observer);
+
+                if (!Services.prefs.getBoolPref(completePref, false)) {
+                  new TRRRacer().run(() => {
+                    Services.prefs.setBoolPref(completePref, true);
+                  });
+                }
+              }
+            });
+          }
+        },
+      },
+
+      // FOG doesn't need to be initialized _too_ early because it has a
+      // pre-init buffer.
+      {
+        task: () => {
+          if (AppConstants.MOZ_GLEAN) {
+            let FOG = Cc["@mozilla.org/toolkit/glean;1"].createInstance(
+              Ci.nsIFOG
+            );
+            FOG.initializeFOG();
+          }
+        },
+      },
+
+      // Add the import button if this is the first startup.
+      {
+        task: async () => {
+          // First check if we've already added the import button, in which
+          // case we should check for events indicating we can remove it.
+          if (
+            Services.prefs.getBoolPref(
+              "browser.bookmarks.addedImportButton",
+              false
+            )
+          ) {
+            PlacesUIUtils.removeImportButtonWhenImportSucceeds();
+            return;
+          }
+
+          // Otherwise, check if this is a new profile where we need to add it.
+          // `maybeAddImportButton` will call
+          // `removeImportButtonWhenImportSucceeds`itself if/when it adds the
+          // button. Doing things in this order avoids listening for removal
+          // more than once.
+          if (
+            this._isNewProfile &&
+            // Not in automation: the button changes CUI state, breaking tests
+            !Cu.isInAutomation
+          ) {
+            await PlacesUIUtils.maybeAddImportButton();
+          }
+        },
+      },
+
+      {
+        task: () => {
+          ASRouterNewTabHook.createInstance(ASRouterDefaultConfig());
+        },
+      },
+
+      {
+        task: () => {
+          PlacesUIUtils.ensureBookmarkToolbarTelemetryListening();
+        },
+      },
+
+      // Marionette needs to be initialized as very last step
+      {
+        task: () => {
+          // Use idleDispatch a second time to run this after the per-window
+          // idle tasks.
+          ChromeUtils.idleDispatch(() => {
+            Services.obs.notifyObservers(
+              null,
+              "browser-startup-idle-tasks-finished"
+            );
+            Services.obs.notifyObservers(null, "marionette-startup-requested");
+          });
+        },
+      },
+      // Do NOT add anything after marionette initialization.
+    ];
+
+    for (let task of idleTasks) {
+      if ("condition" in task && !task.condition) {
+        continue;
+      }
+
+      ChromeUtils.idleDispatch(
+        () => {
+          if (!Services.startup.shuttingDown) {
+            let startTime = Cu.now();
+            try {
+              task.task();
+            } catch (ex) {
+              Cu.reportError(ex);
+            } finally {
+              ChromeUtils.addProfilerMarker("startupIdleTask", startTime);
+            }
+          }
+        },
+        task.timeout ? { timeout: task.timeout } : undefined
+      );
+    }
+  },
+
+  /**
+   * Use this function as an entry point to schedule tasks that we hope
+   * to run once per session, at any arbitrary point in time, and which we
+   * are okay with sometimes not running at all.
+   *
+   * This function will be called from an idle observer. Check the value of
+   * LATE_TASKS_IDLE_TIME_SEC to see the current value for this idle
+   * observer.
+   *
+   * Note: this function may never be called if the user is never idle for the
+   * requisite time (LATE_TASKS_IDLE_TIME_SEC). Be certain before adding
+   * something here that it's okay that it never be run.
+   */
+  _scheduleBestEffortUserIdleTasks() {
+    const idleTasks = [
+      () => {
+        this._sendMediaTelemetry();
+      },
+
+      () => {
+        // Telemetry for master-password - we do this after a delay as it
+        // can cause IO if NSS/PSM has not already initialized.
+        let tokenDB = Cc["@mozilla.org/security/pk11tokendb;1"].getService(
+          Ci.nsIPK11TokenDB
+        );
+        let token = tokenDB.getInternalKeyToken();
+        let mpEnabled = token.hasPassword;
+        if (mpEnabled) {
+          Services.telemetry
+            .getHistogramById("MASTER_PASSWORD_ENABLED")
+            .add(mpEnabled);
+        }
+      },
+
+      () => {
+        let obj = {};
+        ChromeUtils.import("resource://gre/modules/GMPInstallManager.jsm", obj);
+        this._gmpInstallManager = new obj.GMPInstallManager();
+        // We don't really care about the results, if someone is interested they
+        // can check the log.
+        this._gmpInstallManager.simpleCheckAndInstall().catch(() => {});
+      },
+
+      () => {
+        RemoteSettings.init();
+        this._addBreachesSyncHandler();
+      },
+
+      () => {
+        PublicSuffixList.init();
+      },
+
+      () => {
+        RemoteSecuritySettings.init();
+      },
+
+      () => {
+        if (Services.prefs.getBoolPref("corroborator.enabled", false)) {
+          Corroborate.init().catch(Cu.reportError);
+        }
+      },
+
+      () => BrowserUsageTelemetry.reportProfileCount(),
+
+      () => OsEnvironment.reportAllowedAppSources(),
+
+      () => Services.search.checkWebExtensionEngines(),
+    ];
+
+    for (let task of idleTasks) {
+      ChromeUtils.idleDispatch(async () => {
+        if (!Services.startup.shuttingDown) {
+          let startTime = Cu.now();
+          try {
+            await task();
+          } catch (ex) {
+            Cu.reportError(ex);
+          } finally {
+            ChromeUtils.addProfilerMarker("startupLateIdleTask", startTime);
+          }
+        }
+      });
+    }
+  },
+
+  _addBreachesSyncHandler() {
+    if (
+      Services.prefs.getBoolPref(
+        "signon.management.page.breach-alerts.enabled",
+        false
+      )
+    ) {
+      RemoteSettings(LoginBreaches.REMOTE_SETTINGS_COLLECTION).on(
+        "sync",
+        async event => {
+          await LoginBreaches.update(event.data.current);
+        }
+      );
+    }
+  },
+
+  _addBreachAlertsPrefObserver() {
+    const BREACH_ALERTS_PREF = "signon.management.page.breach-alerts.enabled";
+    const clearVulnerablePasswordsIfBreachAlertsDisabled = async function() {
+      if (!Services.prefs.getBoolPref(BREACH_ALERTS_PREF)) {
+        await LoginBreaches.clearAllPotentiallyVulnerablePasswords();
+      }
+    };
+    clearVulnerablePasswordsIfBreachAlertsDisabled();
+    Services.prefs.addObserver(
+      BREACH_ALERTS_PREF,
+      clearVulnerablePasswordsIfBreachAlertsDisabled
+    );
+  },
+
+  _onQuitRequest: function BG__onQuitRequest(aCancelQuit, aQuitType) {
+    // If user has already dismissed quit request, then do nothing
+    if (aCancelQuit instanceof Ci.nsISupportsPRBool && aCancelQuit.data) {
+      return;
+    }
+
+    // There are several cases where we won't show a dialog here:
+    // 1. There is only 1 tab open in 1 window
+    // 2. browser.warnOnQuit == false
+    // 3. The browser is currently in Private Browsing mode
+    // 4. The browser will be restarted.
+    // 5. The user has automatic session restore enabled and
+    //    browser.sessionstore.warnOnQuit is not set to true.
+    // 6. The user doesn't have automatic session restore enabled
+    //    and browser.tabs.warnOnClose is not set to true.
+    //
+    // Otherwise, we will show the "closing multiple tabs" dialog.
+    //
+    // aQuitType == "lastwindow" is overloaded. "lastwindow" is used to indicate
+    // "the last window is closing but we're not quitting (a non-browser window is open)"
+    // and also "we're quitting by closing the last window".
+
+    if (aQuitType == "restart" || aQuitType == "os-restart") {
+      return;
+    }
+
+    var windowcount = 0;
+    var pagecount = 0;
+    for (let win of BrowserWindowTracker.orderedWindows) {
+      if (win.closed) {
+        continue;
+      }
+      windowcount++;
+      let tabbrowser = win.gBrowser;
+      if (tabbrowser) {
+        pagecount +=
+          tabbrowser.browsers.length -
+          tabbrowser._numPinnedTabs -
+          tabbrowser._removingTabs.length;
+      }
+    }
+
+    if (pagecount < 2) {
+      return;
+    }
+
+    if (!aQuitType) {
+      aQuitType = "quit";
+    }
+
+    // browser.warnOnQuit is a hidden global boolean to override all quit prompts
+    if (!Services.prefs.getBoolPref("browser.warnOnQuit")) {
+      return;
+    }
+
+    // If we're going to automatically restore the session, only warn if the user asked for that.
+    let sessionWillBeRestored =
+      Services.prefs.getIntPref("browser.startup.page") == 3 ||
+      Services.prefs.getBoolPref("browser.sessionstore.resume_session_once");
+    // In the sessionWillBeRestored case, we only check the sessionstore-specific pref:
+    if (sessionWillBeRestored) {
+      if (
+        !Services.prefs.getBoolPref("browser.sessionstore.warnOnQuit", false)
+      ) {
+        return;
+      }
+      // Otherwise, we check browser.tabs.warnOnClose
+    } else if (!Services.prefs.getBoolPref("browser.tabs.warnOnClose")) {
+      return;
+    }
+
+    let win = BrowserWindowTracker.getTopWindow();
+
+    let warningMessage;
+    // More than 1 window. Compose our own message.
+    if (windowcount > 1) {
+      let tabSubstring = gTabbrowserBundle.GetStringFromName(
+        "tabs.closeWarningMultipleWindowsTabSnippet"
+      );
+      tabSubstring = PluralForm.get(pagecount, tabSubstring).replace(
+        /#1/,
+        pagecount
+      );
+
+      let stringID = sessionWillBeRestored
+        ? "tabs.closeWarningMultipleWindowsSessionRestore2"
+        : "tabs.closeWarningMultipleWindows";
+      let windowString = gTabbrowserBundle.GetStringFromName(stringID);
+      windowString = PluralForm.get(windowcount, windowString).replace(
+        /#1/,
+        windowcount
+      );
+      warningMessage = windowString.replace(/%(?:1\$)?S/i, tabSubstring);
+    } else {
+      let stringID = sessionWillBeRestored
+        ? "tabs.closeWarningMultipleSessionRestore2"
+        : "tabs.closeWarningMultiple";
+      warningMessage = gTabbrowserBundle.GetStringFromName(stringID);
+      warningMessage = PluralForm.get(pagecount, warningMessage).replace(
+        "#1",
+        pagecount
+      );
+    }
+
+    let warnOnClose = { value: true };
+    let titleId =
+      AppConstants.platform == "win"
+        ? "tabs.closeAndQuitTitleTabsWin"
+        : "tabs.closeAndQuitTitleTabs";
+    let flags =
+      Services.prompt.BUTTON_TITLE_IS_STRING * Services.prompt.BUTTON_POS_0 +
+      Services.prompt.BUTTON_TITLE_CANCEL * Services.prompt.BUTTON_POS_1;
+    // Only display the checkbox in the non-sessionrestore case.
+    let checkboxLabel = !sessionWillBeRestored
+      ? gTabbrowserBundle.GetStringFromName("tabs.closeWarningPromptMe")
+      : null;
+
+    // buttonPressed will be 0 for closing, 1 for cancel (don't close/quit)
+    let buttonPressed = Services.prompt.confirmEx(
+      win,
+      gTabbrowserBundle.GetStringFromName(titleId),
+      warningMessage,
+      flags,
+      gTabbrowserBundle.GetStringFromName("tabs.closeButtonMultiple"),
+      null,
+      null,
+      checkboxLabel,
+      warnOnClose
+    );
+    // If the user has unticked the box, and has confirmed closing, stop showing
+    // the warning.
+    if (!sessionWillBeRestored && buttonPressed == 0 && !warnOnClose.value) {
+      Services.prefs.setBoolPref("browser.tabs.warnOnClose", false);
+    }
+    aCancelQuit.data = buttonPressed != 0;
+  },
+
+  /**
+   * Initialize Places
+   * - imports the bookmarks html file if bookmarks database is empty, try to
+   *   restore bookmarks from a JSON backup if the backend indicates that the
+   *   database was corrupt.
+   *
+   * These prefs can be set up by the frontend:
+   *
+   * WARNING: setting these preferences to true will overwite existing bookmarks
+   *
+   * - browser.places.importBookmarksHTML
+   *   Set to true will import the bookmarks.html file from the profile folder.
+   * - browser.bookmarks.restore_default_bookmarks
+   *   Set to true by safe-mode dialog to indicate we must restore default
+   *   bookmarks.
+   */
+  _initPlaces: function BG__initPlaces(aInitialMigrationPerformed) {
+    // We must instantiate the history service since it will tell us if we
+    // need to import or restore bookmarks due to first-run, corruption or
+    // forced migration (due to a major schema change).
+    // If the database is corrupt or has been newly created we should
+    // import bookmarks.
+    let dbStatus = PlacesUtils.history.databaseStatus;
+
+    // Show a notification with a "more info" link for a locked places.sqlite.
+    if (dbStatus == PlacesUtils.history.DATABASE_STATUS_LOCKED) {
+      // Note: initPlaces should always happen when the first window is ready,
+      // in any case, better safe than sorry.
+      this._firstWindowReady.then(() => {
+        this._showPlacesLockedNotificationBox();
+        this._placesBrowserInitComplete = true;
+        Services.obs.notifyObservers(null, "places-browser-init-complete");
+      });
+      return;
+    }
+
+    let importBookmarks =
+      !aInitialMigrationPerformed &&
+      (dbStatus == PlacesUtils.history.DATABASE_STATUS_CREATE ||
+        dbStatus == PlacesUtils.history.DATABASE_STATUS_CORRUPT);
+
+    // Check if user or an extension has required to import bookmarks.html
+    let importBookmarksHTML = false;
+    try {
+      importBookmarksHTML = Services.prefs.getBoolPref(
+        "browser.places.importBookmarksHTML"
+      );
+      if (importBookmarksHTML) {
+        importBookmarks = true;
+      }
+    } catch (ex) {}
+
+    // Support legacy bookmarks.html format for apps that depend on that format.
+    let autoExportHTML = Services.prefs.getBoolPref(
+      "browser.bookmarks.autoExportHTML",
+      false
+    ); // Do not export.
+    if (autoExportHTML) {
+      // Sqlite.jsm and Places shutdown happen at profile-before-change, thus,
+      // to be on the safe side, this should run earlier.
+      AsyncShutdown.profileChangeTeardown.addBlocker(
+        "Places: export bookmarks.html",
+        () => BookmarkHTMLUtils.exportToFile(BookmarkHTMLUtils.defaultPath)
+      );
+    }
+
+    (async () => {
+      // Check if Safe Mode or the user has required to restore bookmarks from
+      // default profile's bookmarks.html
+      let restoreDefaultBookmarks = false;
+      try {
+        restoreDefaultBookmarks = Services.prefs.getBoolPref(
+          "browser.bookmarks.restore_default_bookmarks"
+        );
+        if (restoreDefaultBookmarks) {
+          // Ensure that we already have a bookmarks backup for today.
+          await this._backupBookmarks();
+          importBookmarks = true;
+        }
+      } catch (ex) {}
+
+      // This may be reused later, check for "=== undefined" to see if it has
+      // been populated already.
+      let lastBackupFile;
+
+      // If the user did not require to restore default bookmarks, or import
+      // from bookmarks.html, we will try to restore from JSON
+      if (importBookmarks && !restoreDefaultBookmarks && !importBookmarksHTML) {
+        // get latest JSON backup
+        lastBackupFile = await PlacesBackups.getMostRecentBackup();
+        if (lastBackupFile) {
+          // restore from JSON backup
+          await BookmarkJSONUtils.importFromFile(lastBackupFile, {
+            replace: true,
+            source: PlacesUtils.bookmarks.SOURCES.RESTORE_ON_STARTUP,
+          });
+          importBookmarks = false;
+        } else {
+          // We have created a new database but we don't have any backup available
+          importBookmarks = true;
+          if (await OS.File.exists(BookmarkHTMLUtils.defaultPath)) {
+            // If bookmarks.html is available in current profile import it...
+            importBookmarksHTML = true;
+          } else {
+            // ...otherwise we will restore defaults
+            restoreDefaultBookmarks = true;
+          }
+        }
+      }
+
+      // Import default bookmarks when necessary.
+      // Otherwise, if any kind of import runs, default bookmarks creation should be
+      // delayed till the import operations has finished.  Not doing so would
+      // cause them to be overwritten by the newly imported bookmarks.
+      if (!importBookmarks) {
+        // Now apply distribution customized bookmarks.
+        // This should always run after Places initialization.
+        try {
+          await this._distributionCustomizer.applyBookmarks();
+        } catch (e) {
+          Cu.reportError(e);
+        }
+      } else {
+        // An import operation is about to run.
+        let bookmarksUrl = null;
+        if (restoreDefaultBookmarks) {
+          // User wants to restore bookmarks.html file from default profile folder
+          bookmarksUrl = "chrome://browser/locale/bookmarks.html";
+        } else if (await OS.File.exists(BookmarkHTMLUtils.defaultPath)) {
+          bookmarksUrl = OS.Path.toFileURI(BookmarkHTMLUtils.defaultPath);
+        }
+
+        if (bookmarksUrl) {
+          // Import from bookmarks.html file.
+          try {
+            if (Services.policies.isAllowed("defaultBookmarks")) {
+              await BookmarkHTMLUtils.importFromURL(bookmarksUrl, {
+                replace: true,
+                source: PlacesUtils.bookmarks.SOURCES.RESTORE_ON_STARTUP,
+              });
+            }
+          } catch (e) {
+            Cu.reportError("Bookmarks.html file could be corrupt. " + e);
+          }
+          try {
+            // Now apply distribution customized bookmarks.
+            // This should always run after Places initialization.
+            await this._distributionCustomizer.applyBookmarks();
+          } catch (e) {
+            Cu.reportError(e);
+          }
+        } else {
+          Cu.reportError(new Error("Unable to find bookmarks.html file."));
+        }
+
+        // Reset preferences, so we won't try to import again at next run
+        if (importBookmarksHTML) {
+          Services.prefs.setBoolPref(
+            "browser.places.importBookmarksHTML",
+            false
+          );
+        }
+        if (restoreDefaultBookmarks) {
+          Services.prefs.setBoolPref(
+            "browser.bookmarks.restore_default_bookmarks",
+            false
+          );
+        }
+      }
+
+      // Initialize bookmark archiving on idle.
+      if (!this._bookmarksBackupIdleTime) {
+        this._bookmarksBackupIdleTime = BOOKMARKS_BACKUP_IDLE_TIME_SEC;
+
+        // If there is no backup, or the last bookmarks backup is too old, use
+        // a more aggressive idle observer.
+        if (lastBackupFile === undefined) {
+          lastBackupFile = await PlacesBackups.getMostRecentBackup();
+        }
+        if (!lastBackupFile) {
+          this._bookmarksBackupIdleTime /= 2;
+        } else {
+          let lastBackupTime = PlacesBackups.getDateForFile(lastBackupFile);
+          let profileLastUse = Services.appinfo.replacedLockTime || Date.now();
+
+          // If there is a backup after the last profile usage date it's fine,
+          // regardless its age.  Otherwise check how old is the last
+          // available backup compared to that session.
+          if (profileLastUse > lastBackupTime) {
+            let backupAge = Math.round(
+              (profileLastUse - lastBackupTime) / 86400000
+            );
+            // Report the age of the last available backup.
+            try {
+              Services.telemetry
+                .getHistogramById("PLACES_BACKUPS_DAYSFROMLAST")
+                .add(backupAge);
+            } catch (ex) {
+              Cu.reportError(new Error("Unable to report telemetry."));
+            }
+
+            if (backupAge > BOOKMARKS_BACKUP_MAX_INTERVAL_DAYS) {
+              this._bookmarksBackupIdleTime /= 2;
+            }
+          }
+        }
+        this._userIdleService.addIdleObserver(
+          this,
+          this._bookmarksBackupIdleTime
+        );
+      }
+
+      if (this._isNewProfile) {
+        try {
+          // New profiles may have existing bookmarks (imported from another browser or
+          // copied into the profile) and we want to show the bookmark toolbar for them
+          // in some cases.
+          PlacesUIUtils.maybeToggleBookmarkToolbarVisibility();
+        } catch (ex) {
+          Cu.reportError(ex);
+        }
+      }
+    })()
+      .catch(ex => {
+        Cu.reportError(ex);
+      })
+      .then(() => {
+        // NB: deliberately after the catch so that we always do this, even if
+        // we threw halfway through initializing in the Task above.
+        this._placesBrowserInitComplete = true;
+        Services.obs.notifyObservers(null, "places-browser-init-complete");
+      });
+  },
+
+  /**
+   * If a backup for today doesn't exist, this creates one.
+   */
+  _backupBookmarks: function BG__backupBookmarks() {
+    return (async function() {
+      let lastBackupFile = await PlacesBackups.getMostRecentBackup();
+      // Should backup bookmarks if there are no backups or the maximum
+      // interval between backups elapsed.
+      if (
+        !lastBackupFile ||
+        new Date() - PlacesBackups.getDateForFile(lastBackupFile) >
+          BOOKMARKS_BACKUP_MIN_INTERVAL_DAYS * 86400000
+      ) {
+        let maxBackups = Services.prefs.getIntPref(
+          "browser.bookmarks.max_backups"
+        );
+        await PlacesBackups.create(maxBackups);
+      }
+    })();
+  },
+
+  /**
+   * Show the notificationBox for a locked places database.
+   */
+  _showPlacesLockedNotificationBox: function BG__showPlacesLockedNotificationBox() {
+    var applicationName = gBrandBundle.GetStringFromName("brandShortName");
+    var placesBundle = Services.strings.createBundle(
+      "chrome://browser/locale/places/places.properties"
+    );
+    var title = placesBundle.GetStringFromName("lockPrompt.title");
+    var text = placesBundle.formatStringFromName("lockPrompt.text", [
+      applicationName,
+    ]);
+    var buttonText = placesBundle.GetStringFromName(
+      "lockPromptInfoButton.label"
+    );
+    var accessKey = placesBundle.GetStringFromName(
+      "lockPromptInfoButton.accessKey"
+    );
+
+    var helpTopic = "places-locked";
+    var url = Services.urlFormatter.formatURLPref("app.support.baseURL");
+    url += helpTopic;
+
+    var win = BrowserWindowTracker.getTopWindow();
+
+    var buttons = [
+      {
+        label: buttonText,
+        accessKey,
+        popup: null,
+        callback(aNotificationBar, aButton) {
+          win.openTrustedLinkIn(url, "tab");
+        },
+      },
+    ];
+
+    var notifyBox = win.gBrowser.getNotificationBox();
+    var notification = notifyBox.appendNotification(
+      text,
+      title,
+      null,
+      notifyBox.PRIORITY_CRITICAL_MEDIUM,
+      buttons
+    );
+    notification.persistence = -1; // Until user closes it
+  },
+
+  _onThisDeviceConnected() {
+    let bundle = Services.strings.createBundle(
+      "chrome://browser/locale/accounts.properties"
+    );
+    let title = bundle.GetStringFromName("deviceConnDisconnTitle");
+    let body = bundle.GetStringFromName("thisDeviceConnectedBody");
+
+    let clickCallback = (subject, topic, data) => {
+      if (topic != "alertclickcallback") {
+        return;
+      }
+      this._openPreferences("sync");
+    };
+    this.AlertsService.showAlertNotification(
+      null,
+      title,
+      body,
+      true,
+      null,
+      clickCallback
+    );
+  },
+
+  _migrateXULStoreForDocument(fromURL, toURL) {
+    Array.from(Services.xulStore.getIDsEnumerator(fromURL)).forEach(id => {
+      Array.from(Services.xulStore.getAttributeEnumerator(fromURL, id)).forEach(
+        attr => {
+          let value = Services.xulStore.getValue(fromURL, id, attr);
+          Services.xulStore.setValue(toURL, id, attr, value);
+        }
+      );
+    });
+  },
+
+  // eslint-disable-next-line complexity
+  _migrateUI: function BG__migrateUI() {
+    // Use an increasing number to keep track of the current migration state.
+    // Completely unrelated to the current Firefox release number.
+    const UI_VERSION = 104;
+    const BROWSER_DOCURL = AppConstants.BROWSER_CHROME_URL;
+
+    if (!Services.prefs.prefHasUserValue("browser.migration.version")) {
+      // This is a new profile, nothing to migrate.
+      Services.prefs.setIntPref("browser.migration.version", UI_VERSION);
+      this._isNewProfile = true;
+      return;
+    }
+
+    this._isNewProfile = false;
+    let currentUIVersion = Services.prefs.getIntPref(
+      "browser.migration.version"
+    );
+    if (currentUIVersion >= UI_VERSION) {
+      return;
+    }
+
+    let xulStore = Services.xulStore;
+
+    if (currentUIVersion < 64) {
+      OS.File.remove(
+        OS.Path.join(OS.Constants.Path.profileDir, "directoryLinks.json"),
+        { ignoreAbsent: true }
+      );
+    }
+
+    if (
+      currentUIVersion < 65 &&
+      Services.prefs.getCharPref("general.config.filename", "") ==
+        "dsengine.cfg"
+    ) {
+      let searchInitializedPromise = new Promise(resolve => {
+        if (Services.search.isInitialized) {
+          resolve();
+        }
+        const SEARCH_SERVICE_TOPIC = "browser-search-service";
+        Services.obs.addObserver(function observer(subject, topic, data) {
+          if (data != "init-complete") {
+            return;
+          }
+          Services.obs.removeObserver(observer, SEARCH_SERVICE_TOPIC);
+          resolve();
+        }, SEARCH_SERVICE_TOPIC);
+      });
+      searchInitializedPromise.then(() => {
+        let engineNames = [
+          "Bing Search Engine",
+          "Yahoo! Search Engine",
+          "Yandex Search Engine",
+        ];
+        for (let engineName of engineNames) {
+          let engine = Services.search.getEngineByName(engineName);
+          if (engine) {
+            Services.search.removeEngine(engine);
+          }
+        }
+      });
+    }
+
+    if (currentUIVersion < 67) {
+      // Migrate devtools firebug theme users to light theme (bug 1378108):
+      if (Services.prefs.getCharPref("devtools.theme") == "firebug") {
+        Services.prefs.setCharPref("devtools.theme", "light");
+      }
+    }
+
+    if (currentUIVersion < 68) {
+      // Remove blocklists legacy storage, now relying on IndexedDB.
+      OS.File.remove(
+        OS.Path.join(OS.Constants.Path.profileDir, "kinto.sqlite"),
+        { ignoreAbsent: true }
+      );
+    }
+
+    if (currentUIVersion < 69) {
+      // Clear old social prefs from profile (bug 1460675)
+      let socialPrefs = Services.prefs.getBranch("social.");
+      if (socialPrefs) {
+        let socialPrefsArray = socialPrefs.getChildList("");
+        for (let item of socialPrefsArray) {
+          Services.prefs.clearUserPref("social." + item);
+        }
+      }
+    }
+
+    if (currentUIVersion < 70) {
+      // Migrate old ctrl-tab pref to new one in existing profiles. (This code
+      // doesn't run at all in new profiles.)
+      Services.prefs.setBoolPref(
+        "browser.ctrlTab.recentlyUsedOrder",
+        Services.prefs.getBoolPref("browser.ctrlTab.previews", false)
+      );
+      Services.prefs.clearUserPref("browser.ctrlTab.previews");
+      // Remember that we migrated the pref in case we decide to flip it for
+      // these users.
+      Services.prefs.setBoolPref("browser.ctrlTab.migrated", true);
+    }
+
+    if (currentUIVersion < 71) {
+      // Clear legacy saved prefs for content handlers.
+      let savedContentHandlers = Services.prefs.getChildList(
+        "browser.contentHandlers.types"
+      );
+      for (let savedHandlerPref of savedContentHandlers) {
+        Services.prefs.clearUserPref(savedHandlerPref);
+      }
+    }
+
+    if (currentUIVersion < 72) {
+      // Migrate performance tool's recording interval value from msec to usec.
+      let pref = "devtools.performance.recording.interval";
+      Services.prefs.setIntPref(
+        pref,
+        Services.prefs.getIntPref(pref, 1) * 1000
+      );
+    }
+
+    if (currentUIVersion < 73) {
+      // Remove blocklist JSON local dumps in profile.
+      OS.File.removeDir(
+        OS.Path.join(OS.Constants.Path.profileDir, "blocklists"),
+        { ignoreAbsent: true }
+      );
+      OS.File.removeDir(
+        OS.Path.join(OS.Constants.Path.profileDir, "blocklists-preview"),
+        { ignoreAbsent: true }
+      );
+      for (const filename of ["addons.json", "plugins.json", "gfx.json"]) {
+        // Some old versions used to dump without subfolders. Clean them while we are at it.
+        const path = OS.Path.join(
+          OS.Constants.Path.profileDir,
+          `blocklists-${filename}`
+        );
+        OS.File.remove(path, { ignoreAbsent: true });
+      }
+    }
+
+    if (currentUIVersion < 76) {
+      // Clear old onboarding prefs from profile (bug 1462415)
+      let onboardingPrefs = Services.prefs.getBranch("browser.onboarding.");
+      if (onboardingPrefs) {
+        let onboardingPrefsArray = onboardingPrefs.getChildList("");
+        for (let item of onboardingPrefsArray) {
+          Services.prefs.clearUserPref("browser.onboarding." + item);
+        }
+      }
+    }
+
+    if (currentUIVersion < 77) {
+      // Remove currentset from all the toolbars
+      let toolbars = [
+        "nav-bar",
+        "PersonalToolbar",
+        "TabsToolbar",
+        "toolbar-menubar",
+      ];
+      for (let toolbarId of toolbars) {
+        xulStore.removeValue(BROWSER_DOCURL, toolbarId, "currentset");
+      }
+    }
+
+    if (currentUIVersion < 78) {
+      Services.prefs.clearUserPref("browser.search.region");
+    }
+
+    if (currentUIVersion < 79) {
+      // The handler app service will read this. We need to wait with migrating
+      // until the handler service has started up, so just set a pref here.
+      Services.prefs.setCharPref("browser.handlers.migrations", "30boxes");
+    }
+
+    if (currentUIVersion < 80) {
+      let hosts = Services.prefs.getCharPref("network.proxy.no_proxies_on");
+      // remove "localhost" and "127.0.0.1" from the no_proxies_on list
+      const kLocalHosts = new Set(["localhost", "127.0.0.1"]);
+      hosts = hosts
+        .split(/[ ,]+/)
+        .filter(host => !kLocalHosts.has(host))
+        .join(", ");
+      Services.prefs.setCharPref("network.proxy.no_proxies_on", hosts);
+    }
+
+    if (currentUIVersion < 81) {
+      // Reset homepage pref for users who have it set to a default from before Firefox 4:
+      //   <locale>.(start|start2|start3).mozilla.(com|org)
+      if (HomePage.overridden) {
+        const DEFAULT = HomePage.getDefault();
+        let value = HomePage.get();
+        let updated = value.replace(
+          /https?:\/\/([\w\-]+\.)?start\d*\.mozilla\.(org|com)[^|]*/gi,
+          DEFAULT
+        );
+        if (updated != value) {
+          if (updated == DEFAULT) {
+            HomePage.reset();
+          } else {
+            value = updated;
+            HomePage.safeSet(value);
+          }
+        }
+      }
+    }
+
+    if (currentUIVersion < 82) {
+      this._migrateXULStoreForDocument(
+        "chrome://browser/content/browser.xul",
+        "chrome://browser/content/browser.xhtml"
+      );
+    }
+
+    if (currentUIVersion < 83) {
+      Services.prefs.clearUserPref("browser.search.reset.status");
+    }
+
+    if (currentUIVersion < 84) {
+      // Reset flash "always allow/block" permissions
+      // We keep session and policy permissions, which could both be
+      // the result of enterprise policy settings. "Never/Always allow"
+      // settings for flash were actually time-bound on recent-ish Firefoxen,
+      // so we remove EXPIRE_TIME entries, too.
+      const { EXPIRE_NEVER, EXPIRE_TIME } = Services.perms;
+      let flashPermissions = Services.perms
+        .getAllWithTypePrefix("plugin:flash")
+        .filter(
+          p =>
+            p.type == "plugin:flash" &&
+            (p.expireType == EXPIRE_NEVER || p.expireType == EXPIRE_TIME)
+        );
+      flashPermissions.forEach(p => Services.perms.removePermission(p));
+    }
+
+    // currentUIVersion < 85 is missing due to the following:
+    // Origianlly, Bug #1568900 added currentUIVersion 85 but was targeting FF70 release.
+    // In between it landing in FF70, Bug #1562601 (currentUIVersion 86) landed and
+    // was uplifted to Beta. To make sure the migration doesn't get skipped, the
+    // code block that was at 85 has been moved/bumped to currentUIVersion 87.
+
+    if (currentUIVersion < 86) {
+      // If the user has set "media.autoplay.allow-muted" to false
+      // migrate that to media.autoplay.default=BLOCKED_ALL.
+      if (
+        Services.prefs.prefHasUserValue("media.autoplay.allow-muted") &&
+        !Services.prefs.getBoolPref("media.autoplay.allow-muted") &&
+        !Services.prefs.prefHasUserValue("media.autoplay.default") &&
+        Services.prefs.getIntPref("media.autoplay.default") ==
+          Ci.nsIAutoplay.BLOCKED
+      ) {
+        Services.prefs.setIntPref(
+          "media.autoplay.default",
+          Ci.nsIAutoplay.BLOCKED_ALL
+        );
+      }
+      Services.prefs.clearUserPref("media.autoplay.allow-muted");
+    }
+
+    if (currentUIVersion < 87) {
+      const TRACKING_TABLE_PREF = "urlclassifier.trackingTable";
+      const CUSTOM_BLOCKING_PREF =
+        "browser.contentblocking.customBlockList.preferences.ui.enabled";
+      // Check if user has set custom tables pref, and show custom block list UI
+      // in the about:preferences#privacy custom panel.
+      if (Services.prefs.prefHasUserValue(TRACKING_TABLE_PREF)) {
+        Services.prefs.setBoolPref(CUSTOM_BLOCKING_PREF, true);
+      }
+    }
+
+    if (currentUIVersion < 88) {
+      // If the user the has "browser.contentblocking.category = custom", but has
+      // the exact same settings as "standard", move them once to "standard". This is
+      // to reset users who we may have moved accidentally, or moved to get ETP early.
+      let category_prefs = [
+        "network.cookie.cookieBehavior",
+        "privacy.trackingprotection.pbmode.enabled",
+        "privacy.trackingprotection.enabled",
+        "privacy.trackingprotection.socialtracking.enabled",
+        "privacy.trackingprotection.fingerprinting.enabled",
+        "privacy.trackingprotection.cryptomining.enabled",
+      ];
+      if (
+        Services.prefs.getStringPref(
+          "browser.contentblocking.category",
+          "standard"
+        ) == "custom"
+      ) {
+        let shouldMigrate = true;
+        for (let pref of category_prefs) {
+          if (Services.prefs.prefHasUserValue(pref)) {
+            shouldMigrate = false;
+          }
+        }
+        if (shouldMigrate) {
+          Services.prefs.setStringPref(
+            "browser.contentblocking.category",
+            "standard"
+          );
+        }
+      }
+    }
+
+    if (currentUIVersion < 89) {
+      // This file was renamed in https://bugzilla.mozilla.org/show_bug.cgi?id=1595636.
+      this._migrateXULStoreForDocument(
+        "chrome://devtools/content/framework/toolbox-window.xul",
+        "chrome://devtools/content/framework/toolbox-window.xhtml"
+      );
+    }
+
+    if (currentUIVersion < 90) {
+      this._migrateXULStoreForDocument(
+        "chrome://browser/content/places/historySidebar.xul",
+        "chrome://browser/content/places/historySidebar.xhtml"
+      );
+      this._migrateXULStoreForDocument(
+        "chrome://browser/content/places/places.xul",
+        "chrome://browser/content/places/places.xhtml"
+      );
+      this._migrateXULStoreForDocument(
+        "chrome://browser/content/places/bookmarksSidebar.xul",
+        "chrome://browser/content/places/bookmarksSidebar.xhtml"
+      );
+    }
+
+    // Clear socks proxy values if they were shared from http, to prevent
+    // websocket breakage after bug 1577862 (see bug 969282).
+    if (
+      currentUIVersion < 91 &&
+      Services.prefs.getBoolPref("network.proxy.share_proxy_settings", false) &&
+      Services.prefs.getIntPref("network.proxy.type", 0) == 1
+    ) {
+      let httpProxy = Services.prefs.getCharPref("network.proxy.http", "");
+      let httpPort = Services.prefs.getIntPref("network.proxy.http_port", 0);
+      let socksProxy = Services.prefs.getCharPref("network.proxy.socks", "");
+      let socksPort = Services.prefs.getIntPref("network.proxy.socks_port", 0);
+      if (httpProxy && httpProxy == socksProxy && httpPort == socksPort) {
+        Services.prefs.setCharPref(
+          "network.proxy.socks",
+          Services.prefs.getCharPref("network.proxy.backup.socks", "")
+        );
+        Services.prefs.setIntPref(
+          "network.proxy.socks_port",
+          Services.prefs.getIntPref("network.proxy.backup.socks_port", 0)
+        );
+      }
+    }
+
+    if (currentUIVersion < 92) {
+      // privacy.userContext.longPressBehavior pref was renamed and changed to a boolean
+      let longpress = Services.prefs.getIntPref(
+        "privacy.userContext.longPressBehavior",
+        0
+      );
+      if (longpress == 1) {
+        Services.prefs.setBoolPref(
+          "privacy.userContext.newTabContainerOnLeftClick.enabled",
+          true
+        );
+      }
+    }
+
+    if (currentUIVersion < 93) {
+      // The Gecko Profiler Addon is now an internal component. Remove the old
+      // addon, and enable the new UI.
+
+      function enableProfilerButton(wasAddonActive) {
+        // Enable the feature pref. This will add it to the customization palette,
+        // but not to the the navbar.
+        Services.prefs.setBoolPref(
+          "devtools.performance.popup.feature-flag",
+          true
+        );
+
+        if (wasAddonActive) {
+          const { ProfilerMenuButton } = ChromeUtils.import(
+            "resource://devtools/client/performance-new/popup/menu-button.jsm.js"
+          );
+          if (!ProfilerMenuButton.isInNavbar()) {
+            // The profiler menu button is not enabled. Turn it on now.
+            const win = BrowserWindowTracker.getTopWindow();
+            if (win && win.document) {
+              ProfilerMenuButton.addToNavbar(win.document);
+            }
+          }
+        }
+      }
+
+      let addonPromise;
+      try {
+        addonPromise = AddonManager.getAddonByID("geckoprofiler@mozilla.com");
+      } catch (error) {
+        Cu.reportError(
+          "Could not access the AddonManager to upgrade the profile. This is most " +
+            "likely because the upgrader is being run from an xpcshell test where " +
+            "the AddonManager is not initialized."
+        );
+      }
+      Promise.resolve(addonPromise).then(addon => {
+        if (!addon) {
+          // Either the addon wasn't installed, or the call to getAddonByID failed.
+          return;
+        }
+        // Remove the old addon.
+        const wasAddonActive = addon.isActive;
+        addon
+          .uninstall()
+          .catch(Cu.reportError)
+          .then(() => enableProfilerButton(wasAddonActive))
+          .catch(Cu.reportError);
+      }, Cu.reportError);
+    }
+
+    // Clear unused socks proxy backup values - see bug 1625773.
+    if (currentUIVersion < 94) {
+      let backup = Services.prefs.getCharPref("network.proxy.backup.socks", "");
+      let backupPort = Services.prefs.getIntPref(
+        "network.proxy.backup.socks_port",
+        0
+      );
+      let socksProxy = Services.prefs.getCharPref("network.proxy.socks", "");
+      let socksPort = Services.prefs.getIntPref("network.proxy.socks_port", 0);
+      if (backup == socksProxy) {
+        Services.prefs.clearUserPref("network.proxy.backup.socks");
+      }
+      if (backupPort == socksPort) {
+        Services.prefs.clearUserPref("network.proxy.backup.socks_port");
+      }
+    }
+
+    if (currentUIVersion < 95) {
+      const oldPrefName = "media.autoplay.enabled.user-gestures-needed";
+      const oldPrefValue = Services.prefs.getBoolPref(oldPrefName, true);
+      const newPrefValue = oldPrefValue ? 0 : 1;
+      Services.prefs.setIntPref("media.autoplay.blocking_policy", newPrefValue);
+      Services.prefs.clearUserPref(oldPrefName);
+    }
+
+    if (currentUIVersion < 96) {
+      const oldPrefName = "browser.urlbar.openViewOnFocus";
+      const oldPrefValue = Services.prefs.getBoolPref(oldPrefName, true);
+      Services.prefs.setBoolPref(
+        "browser.urlbar.suggest.topsites",
+        oldPrefValue
+      );
+      Services.prefs.clearUserPref(oldPrefName);
+    }
+
+    if (currentUIVersion < 97) {
+      let userCustomizedWheelMax = Services.prefs.prefHasUserValue(
+        "general.smoothScroll.mouseWheel.durationMaxMS"
+      );
+      let userCustomizedWheelMin = Services.prefs.prefHasUserValue(
+        "general.smoothScroll.mouseWheel.durationMinMS"
+      );
+
+      if (!userCustomizedWheelMin && !userCustomizedWheelMax) {
+        // If the user has an existing profile but hasn't customized the wheel
+        // animation duration, indicate that they need to be migrated to the new
+        // values by setting their "migration complete" percentage to 0.
+        Services.prefs.setIntPref(
+          "general.smoothScroll.mouseWheel.migrationPercent",
+          0
+        );
+      } else if (userCustomizedWheelMin && !userCustomizedWheelMax) {
+        // If they customized just one of the two, save the old value for the
+        // other one as well, because the two values go hand-in-hand and we
+        // don't want to move just one to a new value and leave the other one
+        // at a customized value. In both of these cases, we leave the "migration
+        // complete" percentage at 100, because they have customized this and
+        // don't need any further migration.
+        Services.prefs.setIntPref(
+          "general.smoothScroll.mouseWheel.durationMaxMS",
+          400
+        );
+      } else if (!userCustomizedWheelMin && userCustomizedWheelMax) {
+        // Same as above case, but for the other pref.
+        Services.prefs.setIntPref(
+          "general.smoothScroll.mouseWheel.durationMinMS",
+          200
+        );
+      } else {
+        // The last remaining case is if they customized both values, in which
+        // case also we leave the "migration complete" percentage at 100, as no
+        // further migration is needed.
+      }
+    }
+
+    if (currentUIVersion < 98) {
+      Services.prefs.clearUserPref("browser.search.cohort");
+    }
+
+    if (currentUIVersion < 99) {
+      Services.prefs.clearUserPref("security.tls.version.enable-deprecated");
+    }
+
+    if (currentUIVersion < 102) {
+      // In Firefox 83, we moved to a dynamic button, so it needs to be removed
+      // from default placement. This is done early enough that it doesn't
+      // impact adding new managed bookmarks.
+      const { CustomizableUI } = ChromeUtils.import(
+        "resource:///modules/CustomizableUI.jsm"
+      );
+      CustomizableUI.removeWidgetFromArea("managed-bookmarks");
+    }
+
+    // We have to rerun these because we had to use 102 on beta.
+    // They were 101 and 102 before.
+    if (currentUIVersion < 103) {
+      // Set a pref if the bookmarks toolbar was already visible,
+      // so we can keep it visible when navigating away from newtab
+      let bookmarksToolbarWasVisible =
+        Services.xulStore.getValue(
+          BROWSER_DOCURL,
+          "PersonalToolbar",
+          "collapsed"
+        ) == "false";
+      if (bookmarksToolbarWasVisible) {
+        // Migrate the user to the "always visible" value. See firefox.js for
+        // the other possible states.
+        Services.prefs.setCharPref(
+          "browser.toolbars.bookmarks.visibility",
+          "always"
+        );
+      }
+      Services.xulStore.removeValue(
+        BROWSER_DOCURL,
+        "PersonalToolbar",
+        "collapsed"
+      );
+
+      Services.prefs.clearUserPref(
+        "browser.livebookmarks.migrationAttemptsLeft"
+      );
+    }
+
+    // For existing profiles, continue putting bookmarks in the
+    // "other bookmarks" folder.
+    if (currentUIVersion < 104) {
+      Services.prefs.setCharPref(
+        "browser.bookmarks.defaultLocation",
+        "unfiled"
+      );
+    }
+
+    // Update the migration version.
+    Services.prefs.setIntPref("browser.migration.version", UI_VERSION);
+  },
+
+  _maybeShowDefaultBrowserPrompt() {
+    Promise.all([
+      DefaultBrowserCheck.willCheckDefaultBrowser(/* isStartupCheck */ true),
+      ExperimentAPI.ready,
+    ]).then(async ([willPrompt]) => {
+      let { DefaultBrowserNotification } = ChromeUtils.import(
+        "resource:///actors/AboutNewTabParent.jsm",
+        {}
+      );
+      let isFeatureEnabled = false;
+      try {
+        isFeatureEnabled = ExperimentAPI.getExperiment({
+          featureId: "infobar",
+          sendExposurePing: false,
+        })?.branch.feature.enabled;
+      } catch (e) {}
+      if (willPrompt) {
+        // Prevent the related notification from appearing and
+        // show the modal prompt.
+        DefaultBrowserNotification.notifyModalDisplayed();
+      }
+      // If no experiment go ahead with default experience
+      if (willPrompt && !isFeatureEnabled) {
+        let win = BrowserWindowTracker.getTopWindow();
+        DefaultBrowserCheck.prompt(win);
+      }
+      // If in experiment notify ASRouter to dispatch message
+      if (isFeatureEnabled) {
+        ASRouter.waitForInitialized.then(() =>
+          ASRouter.sendTriggerMessage({
+            browser: BrowserWindowTracker.getTopWindow()?.gBrowser
+              .selectedBrowser,
+            // triggerId and triggerContext
+            id: "defaultBrowserCheck",
+            context: { willShowDefaultPrompt: willPrompt },
+          })
+        );
+      }
+    });
+  },
+
+  /**
+   * Open preferences even if there are no open windows.
+   */
+  _openPreferences(...args) {
+    let chromeWindow = BrowserWindowTracker.getTopWindow();
+    if (chromeWindow) {
+      chromeWindow.openPreferences(...args);
+      return;
+    }
+
+    if (Services.appShell.hiddenDOMWindow.openPreferences) {
+      Services.appShell.hiddenDOMWindow.openPreferences(...args);
+    }
+  },
+
+  _openURLInNewWindow(url) {
+    let urlString = Cc["@mozilla.org/supports-string;1"].createInstance(
+      Ci.nsISupportsString
+    );
+    urlString.data = url;
+    return new Promise(resolve => {
+      let win = Services.ww.openWindow(
+        null,
+        AppConstants.BROWSER_CHROME_URL,
+        "_blank",
+        "chrome,all,dialog=no",
+        urlString
+      );
+      win.addEventListener(
+        "load",
+        () => {
+          resolve(win);
+        },
+        { once: true }
+      );
+    });
+  },
+
+  /**
+   * Called as an observer when Sync's "display URIs" notification is fired.
+   *
+   * We open the received URIs in background tabs.
+   */
+  async _onDisplaySyncURIs(data) {
+    try {
+      // The payload is wrapped weirdly because of how Sync does notifications.
+      const URIs = data.wrappedJSObject.object;
+
+      // win can be null, but it's ok, we'll assign it later in openTab()
+      let win = BrowserWindowTracker.getTopWindow({ private: false });
+
+      const openTab = async URI => {
+        let tab;
+        if (!win) {
+          win = await this._openURLInNewWindow(URI.uri);
+          let tabs = win.gBrowser.tabs;
+          tab = tabs[tabs.length - 1];
+        } else {
+          tab = win.gBrowser.addWebTab(URI.uri);
+        }
+        tab.setAttribute("attention", true);
+        return tab;
+      };
+
+      const firstTab = await openTab(URIs[0]);
+      await Promise.all(URIs.slice(1).map(URI => openTab(URI)));
+
+      const deviceName = URIs[0].sender && URIs[0].sender.name;
+      let title, body;
+      const bundle = Services.strings.createBundle(
+        "chrome://browser/locale/accounts.properties"
+      );
+      if (URIs.length == 1) {
+        // Due to bug 1305895, tabs from iOS may not have device information, so
+        // we have separate strings to handle those cases. (See Also
+        // unnamedTabsArrivingNotificationNoDevice.body below)
+        if (deviceName) {
+          title = bundle.formatStringFromName(
+            "tabArrivingNotificationWithDevice.title",
+            [deviceName]
+          );
+        } else {
+          title = bundle.GetStringFromName("tabArrivingNotification.title");
+        }
+        // Use the page URL as the body. We strip the fragment and query (after
+        // the `?` and `#` respectively) to reduce size, and also format it the
+        // same way that the url bar would.
+        body = URIs[0].uri.replace(/([?#]).*$/, "$1");
+        let wasTruncated = body.length < URIs[0].uri.length;
+        body = BrowserUtils.trimURL(body);
+        if (wasTruncated) {
+          body = bundle.formatStringFromName(
+            "singleTabArrivingWithTruncatedURL.body",
+            [body]
+          );
+        }
+      } else {
+        title = bundle.GetStringFromName(
+          "multipleTabsArrivingNotification.title"
+        );
+        const allKnownSender = URIs.every(URI => URI.sender != null);
+        const allSameDevice =
+          allKnownSender &&
+          URIs.every(URI => URI.sender.id == URIs[0].sender.id);
+        let tabArrivingBody;
+        if (allSameDevice) {
+          if (deviceName) {
+            tabArrivingBody = "unnamedTabsArrivingNotification2.body";
+          } else {
+            tabArrivingBody = "unnamedTabsArrivingNotificationNoDevice.body";
+          }
+        } else {
+          tabArrivingBody = "unnamedTabsArrivingNotificationMultiple2.body";
+        }
+
+        body = bundle.GetStringFromName(tabArrivingBody);
+        body = PluralForm.get(URIs.length, body);
+        body = body.replace("#1", URIs.length);
+        body = body.replace("#2", deviceName);
+      }
+
+      const clickCallback = (obsSubject, obsTopic, obsData) => {
+        if (obsTopic == "alertclickcallback") {
+          win.gBrowser.selectedTab = firstTab;
+        }
+      };
+
+      // Specify an icon because on Windows no icon is shown at the moment
+      let imageURL;
+      if (AppConstants.platform == "win") {
+        imageURL = "chrome://branding/content/icon64.png";
+      }
+      this.AlertsService.showAlertNotification(
+        imageURL,
+        title,
+        body,
+        true,
+        null,
+        clickCallback
+      );
+    } catch (ex) {
+      Cu.reportError("Error displaying tab(s) received by Sync: " + ex);
+    }
+  },
+
+  async _onVerifyLoginNotification({ body, title, url }) {
+    let tab;
+    let imageURL;
+    if (AppConstants.platform == "win") {
+      imageURL = "chrome://branding/content/icon64.png";
+    }
+    let win = BrowserWindowTracker.getTopWindow({ private: false });
+    if (!win) {
+      win = await this._openURLInNewWindow(url);
+      let tabs = win.gBrowser.tabs;
+      tab = tabs[tabs.length - 1];
+    } else {
+      tab = win.gBrowser.addWebTab(url);
+    }
+    tab.setAttribute("attention", true);
+    let clickCallback = (subject, topic, data) => {
+      if (topic != "alertclickcallback") {
+        return;
+      }
+      win.gBrowser.selectedTab = tab;
+    };
+
+    try {
+      this.AlertsService.showAlertNotification(
+        imageURL,
+        title,
+        body,
+        true,
+        null,
+        clickCallback
+      );
+    } catch (ex) {
+      Cu.reportError("Error notifying of a verify login event: " + ex);
+    }
+  },
+
+  _onDeviceConnected(deviceName) {
+    let accountsBundle = Services.strings.createBundle(
+      "chrome://browser/locale/accounts.properties"
+    );
+    let title = accountsBundle.GetStringFromName("deviceConnDisconnTitle");
+    let body = accountsBundle.formatStringFromName(
+      "otherDeviceConnectedBody" + (deviceName ? "" : ".noDeviceName"),
+      [deviceName]
+    );
+
+    let clickCallback = async (subject, topic, data) => {
+      if (topic != "alertclickcallback") {
+        return;
+      }
+      let url = await FxAccounts.config.promiseManageDevicesURI(
+        "device-connected-notification"
+      );
+      let win = BrowserWindowTracker.getTopWindow({ private: false });
+      if (!win) {
+        this._openURLInNewWindow(url);
+      } else {
+        win.gBrowser.addWebTab(url);
+      }
+    };
+
+    try {
+      this.AlertsService.showAlertNotification(
+        null,
+        title,
+        body,
+        true,
+        null,
+        clickCallback
+      );
+    } catch (ex) {
+      Cu.reportError("Error notifying of a new Sync device: " + ex);
+    }
+  },
+
+  _onDeviceDisconnected() {
+    let bundle = Services.strings.createBundle(
+      "chrome://browser/locale/accounts.properties"
+    );
+    let title = bundle.GetStringFromName("deviceConnDisconnTitle");
+    let body = bundle.GetStringFromName("thisDeviceDisconnectedBody");
+
+    let clickCallback = (subject, topic, data) => {
+      if (topic != "alertclickcallback") {
+        return;
+      }
+      this._openPreferences("sync");
+    };
+    this.AlertsService.showAlertNotification(
+      null,
+      title,
+      body,
+      true,
+      null,
+      clickCallback
+    );
+  },
+
+  _handleFlashHang() {
+    ++this._flashHangCount;
+    if (this._flashHangCount < 2) {
+      return;
+    }
+    // protected mode only applies to win32
+    if (Services.appinfo.XPCOMABI != "x86-msvc") {
+      return;
+    }
+
+    if (
+      Services.prefs.getBoolPref("dom.ipc.plugins.flash.disable-protected-mode")
+    ) {
+      return;
+    }
+    if (
+      !Services.prefs.getBoolPref("browser.flash-protected-mode-flip.enable")
+    ) {
+      return;
+    }
+    if (Services.prefs.getBoolPref("browser.flash-protected-mode-flip.done")) {
+      return;
+    }
+    Services.prefs.setBoolPref(
+      "dom.ipc.plugins.flash.disable-protected-mode",
+      true
+    );
+    Services.prefs.setBoolPref("browser.flash-protected-mode-flip.done", true);
+
+    let win = BrowserWindowTracker.getTopWindow();
+    if (!win) {
+      return;
+    }
+    let productName = gBrandBundle.GetStringFromName("brandShortName");
+    let message = win.gNavigatorBundle.getFormattedString("flashHang.message", [
+      productName,
+    ]);
+    let buttons = [
+      {
+        label: win.gNavigatorBundle.getString("flashHang.helpButton.label"),
+        accessKey: win.gNavigatorBundle.getString(
+          "flashHang.helpButton.accesskey"
+        ),
+        callback() {
+          win.openTrustedLinkIn(
+            "https://support.mozilla.org/kb/flash-protected-mode-autodisabled",
+            "tab"
+          );
+        },
+      },
+    ];
+
+    win.gNotificationBox.appendNotification(
+      message,
+      "flash-hang",
+      null,
+      win.gNotificationBox.PRIORITY_INFO_MEDIUM,
+      buttons
+    );
+  },
+
+  _updateFxaBadges() {
+    let state = UIState.get();
+    if (
+      state.status == UIState.STATUS_LOGIN_FAILED ||
+      state.status == UIState.STATUS_NOT_VERIFIED
+    ) {
+      AppMenuNotifications.showBadgeOnlyNotification(
+        "fxa-needs-authentication"
+      );
+    } else {
+      AppMenuNotifications.removeNotification("fxa-needs-authentication");
+    }
+  },
+
+  QueryInterface: ChromeUtils.generateQI([
+    "nsIObserver",
+    "nsISupportsWeakReference",
+  ]),
+};
+
+var ContentBlockingCategoriesPrefs = {
+  PREF_CB_CATEGORY: "browser.contentblocking.category",
+  PREF_STRICT_DEF: "browser.contentblocking.features.strict",
+  switchingCategory: false,
+
+  setPrefExpectations() {
+    // The prefs inside CATEGORY_PREFS are initial values.
+    // If the pref remains null, then it will expect the default value.
+    // The "standard" category is defined as expecting all 5 default values.
+    this.CATEGORY_PREFS = {
+      strict: {
+        "network.cookie.cookieBehavior": null,
+        "privacy.trackingprotection.pbmode.enabled": null,
+        "privacy.trackingprotection.enabled": null,
+        "privacy.trackingprotection.socialtracking.enabled": null,
+        "privacy.trackingprotection.fingerprinting.enabled": null,
+        "privacy.trackingprotection.cryptomining.enabled": null,
+        "privacy.annotate_channels.strict_list.enabled": null,
+      },
+      standard: {
+        "network.cookie.cookieBehavior": null,
+        "privacy.trackingprotection.pbmode.enabled": null,
+        "privacy.trackingprotection.enabled": null,
+        "privacy.trackingprotection.socialtracking.enabled": null,
+        "privacy.trackingprotection.fingerprinting.enabled": null,
+        "privacy.trackingprotection.cryptomining.enabled": null,
+        "privacy.annotate_channels.strict_list.enabled": null,
+      },
+    };
+    let type = "strict";
+    let rulesArray = Services.prefs
+      .getStringPref(this.PREF_STRICT_DEF)
+      .split(",");
+    for (let item of rulesArray) {
+      switch (item) {
+        case "tp":
+          this.CATEGORY_PREFS[type][
+            "privacy.trackingprotection.enabled"
+          ] = true;
+          break;
+        case "-tp":
+          this.CATEGORY_PREFS[type][
+            "privacy.trackingprotection.enabled"
+          ] = false;
+          break;
+        case "tpPrivate":
+          this.CATEGORY_PREFS[type][
+            "privacy.trackingprotection.pbmode.enabled"
+          ] = true;
+          break;
+        case "-tpPrivate":
+          this.CATEGORY_PREFS[type][
+            "privacy.trackingprotection.pbmode.enabled"
+          ] = false;
+          break;
+        case "fp":
+          this.CATEGORY_PREFS[type][
+            "privacy.trackingprotection.fingerprinting.enabled"
+          ] = true;
+          break;
+        case "-fp":
+          this.CATEGORY_PREFS[type][
+            "privacy.trackingprotection.fingerprinting.enabled"
+          ] = false;
+          break;
+        case "cm":
+          this.CATEGORY_PREFS[type][
+            "privacy.trackingprotection.cryptomining.enabled"
+          ] = true;
+          break;
+        case "-cm":
+          this.CATEGORY_PREFS[type][
+            "privacy.trackingprotection.cryptomining.enabled"
+          ] = false;
+          break;
+        case "stp":
+          this.CATEGORY_PREFS[type][
+            "privacy.trackingprotection.socialtracking.enabled"
+          ] = true;
+          break;
+        case "-stp":
+          this.CATEGORY_PREFS[type][
+            "privacy.trackingprotection.socialtracking.enabled"
+          ] = false;
+          break;
+        case "lvl2":
+          this.CATEGORY_PREFS[type][
+            "privacy.annotate_channels.strict_list.enabled"
+          ] = true;
+          break;
+        case "-lvl2":
+          this.CATEGORY_PREFS[type][
+            "privacy.annotate_channels.strict_list.enabled"
+          ] = false;
+          break;
+        case "cookieBehavior0":
+          this.CATEGORY_PREFS[type]["network.cookie.cookieBehavior"] =
+            Ci.nsICookieService.BEHAVIOR_ACCEPT;
+          break;
+        case "cookieBehavior1":
+          this.CATEGORY_PREFS[type]["network.cookie.cookieBehavior"] =
+            Ci.nsICookieService.BEHAVIOR_REJECT_FOREIGN;
+          break;
+        case "cookieBehavior2":
+          this.CATEGORY_PREFS[type]["network.cookie.cookieBehavior"] =
+            Ci.nsICookieService.BEHAVIOR_REJECT;
+          break;
+        case "cookieBehavior3":
+          this.CATEGORY_PREFS[type]["network.cookie.cookieBehavior"] =
+            Ci.nsICookieService.BEHAVIOR_LIMIT_FOREIGN;
+          break;
+        case "cookieBehavior4":
+          this.CATEGORY_PREFS[type]["network.cookie.cookieBehavior"] =
+            Ci.nsICookieService.BEHAVIOR_REJECT_TRACKER;
+          break;
+        case "cookieBehavior5":
+          this.CATEGORY_PREFS[type]["network.cookie.cookieBehavior"] =
+            Ci.nsICookieService.BEHAVIOR_REJECT_TRACKER_AND_PARTITION_FOREIGN;
+          break;
+        default:
+          Cu.reportError(`Error: Unknown rule observed ${item}`);
+      }
+    }
+  },
+
+  /**
+   * Checks if CB prefs match perfectly with one of our pre-defined categories.
+   */
+  prefsMatch(category) {
+    // The category pref must be either unset, or match.
+    if (
+      Services.prefs.prefHasUserValue(this.PREF_CB_CATEGORY) &&
+      Services.prefs.getStringPref(this.PREF_CB_CATEGORY) != category
+    ) {
+      return false;
+    }
+    for (let pref in this.CATEGORY_PREFS[category]) {
+      let value = this.CATEGORY_PREFS[category][pref];
+      if (value == null) {
+        if (Services.prefs.prefHasUserValue(pref)) {
+          return false;
+        }
+      } else {
+        let prefType = Services.prefs.getPrefType(pref);
+        if (
+          (prefType == Services.prefs.PREF_BOOL &&
+            Services.prefs.getBoolPref(pref) != value) ||
+          (prefType == Services.prefs.PREF_INT &&
+            Services.prefs.getIntPref(pref) != value) ||
+          (prefType == Services.prefs.PREF_STRING &&
+            Services.prefs.getStringPref(pref) != value)
+        ) {
+          return false;
+        }
+      }
+    }
+    return true;
+  },
+
+  matchCBCategory() {
+    if (this.switchingCategory) {
+      return;
+    }
+    // If PREF_CB_CATEGORY is not set match users to a Content Blocking category. Check if prefs fit
+    // perfectly into strict or standard, otherwise match with custom. If PREF_CB_CATEGORY has previously been set,
+    // a change of one of these prefs necessarily puts us in "custom".
+    if (this.prefsMatch("standard")) {
+      Services.prefs.setStringPref(this.PREF_CB_CATEGORY, "standard");
+    } else if (this.prefsMatch("strict")) {
+      Services.prefs.setStringPref(this.PREF_CB_CATEGORY, "strict");
+    } else {
+      Services.prefs.setStringPref(this.PREF_CB_CATEGORY, "custom");
+    }
+
+    // If there is a custom policy which changes a related pref, then put the user in custom so
+    // they still have access to other content blocking prefs, and to keep our default definitions
+    // from changing.
+    let policy = Services.policies.getActivePolicies();
+    if (policy && (policy.EnableTrackingProtection || policy.Cookies)) {
+      Services.prefs.setStringPref(this.PREF_CB_CATEGORY, "custom");
+    }
+  },
+
+  updateCBCategory() {
+    if (
+      this.switchingCategory ||
+      !Services.prefs.prefHasUserValue(this.PREF_CB_CATEGORY)
+    ) {
+      return;
+    }
+    // Turn on switchingCategory flag, to ensure that when the individual prefs that change as a result
+    // of the category change do not trigger yet another category change.
+    this.switchingCategory = true;
+    let value = Services.prefs.getStringPref(this.PREF_CB_CATEGORY);
+    this.setPrefsToCategory(value);
+    this.switchingCategory = false;
+  },
+
+  /**
+   * Sets all user-exposed content blocking preferences to values that match the selected category.
+   */
+  setPrefsToCategory(category) {
+    // Leave prefs as they were if we are switching to "custom" category.
+    if (category == "custom") {
+      return;
+    }
+
+    for (let pref in this.CATEGORY_PREFS[category]) {
+      let value = this.CATEGORY_PREFS[category][pref];
+      if (!Services.prefs.prefIsLocked(pref)) {
+        if (value == null) {
+          Services.prefs.clearUserPref(pref);
+        } else {
+          switch (Services.prefs.getPrefType(pref)) {
+            case Services.prefs.PREF_BOOL:
+              Services.prefs.setBoolPref(pref, value);
+              break;
+            case Services.prefs.PREF_INT:
+              Services.prefs.setIntPref(pref, value);
+              break;
+            case Services.prefs.PREF_STRING:
+              Services.prefs.setStringPref(pref, value);
+              break;
+          }
+        }
+      }
+    }
+  },
+};
+
+/**
+ * ContentPermissionIntegration is responsible for showing the user
+ * simple permission prompts when content requests additional
+ * capabilities.
+ *
+ * While there are some built-in permission prompts, createPermissionPrompt
+ * can also be overridden by system add-ons or tests to provide new ones.
+ *
+ * This override ability is provided by Integration.jsm. See
+ * PermissionUI.jsm for an example of how to provide a new prompt
+ * from an add-on.
+ */
+const ContentPermissionIntegration = {
+  /**
+   * Creates a PermissionPrompt for a given permission type and
+   * nsIContentPermissionRequest.
+   *
+   * @param {string} type
+   *        The type of the permission request from content. This normally
+   *        matches the "type" field of an nsIContentPermissionType, but it
+   *        can be something else if the permission does not use the
+   *        nsIContentPermissionRequest model. Note that this type might also
+   *        be different from the permission key used in the permissions
+   *        database.
+   *        Example: "geolocation"
+   * @param {nsIContentPermissionRequest} request
+   *        The request for a permission from content.
+   * @return {PermissionPrompt} (see PermissionUI.jsm),
+   *         or undefined if the type cannot be handled.
+   */
+  createPermissionPrompt(type, request) {
+    switch (type) {
+      case "geolocation": {
+        return new PermissionUI.GeolocationPermissionPrompt(request);
+      }
+      case "xr": {
+        return new PermissionUI.XRPermissionPrompt(request);
+      }
+      case "desktop-notification": {
+        return new PermissionUI.DesktopNotificationPermissionPrompt(request);
+      }
+      case "persistent-storage": {
+        return new PermissionUI.PersistentStoragePermissionPrompt(request);
+      }
+      case "midi": {
+        return new PermissionUI.MIDIPermissionPrompt(request);
+      }
+      case "storage-access": {
+        return new PermissionUI.StorageAccessPermissionPrompt(request);
+      }
+    }
+    return undefined;
+  },
+};
+
+function ContentPermissionPrompt() {}
+
+ContentPermissionPrompt.prototype = {
+  classID: Components.ID("{d8903bf6-68d5-4e97-bcd1-e4d3012f721a}"),
+
+  QueryInterface: ChromeUtils.generateQI(["nsIContentPermissionPrompt"]),
+
+  /**
+   * This implementation of nsIContentPermissionPrompt.prompt ensures
+   * that there's only one nsIContentPermissionType in the request,
+   * and that it's of type nsIContentPermissionType. Failing to
+   * satisfy either of these conditions will result in this method
+   * throwing NS_ERRORs. If the combined ContentPermissionIntegration
+   * cannot construct a prompt for this particular request, an
+   * NS_ERROR_FAILURE will be thrown.
+   *
+   * Any time an error is thrown, the nsIContentPermissionRequest is
+   * cancelled automatically.
+   *
+   * @param {nsIContentPermissionRequest} request
+   *        The request that we're to show a prompt for.
+   */
+  prompt(request) {
+    if (request.element && request.element.fxrPermissionPrompt) {
+      // For Firefox Reality on Desktop, switch to a different mechanism to
+      // prompt the user since fewer permissions are available and since many
+      // UI dependencies are not availabe.
+      request.element.fxrPermissionPrompt(request);
+      return;
+    }
+
+    let type;
+    try {
+      // Only allow exactly one permission request here.
+      let types = request.types.QueryInterface(Ci.nsIArray);
+      if (types.length != 1) {
+        throw Components.Exception(
+          "Expected an nsIContentPermissionRequest with only 1 type.",
+          Cr.NS_ERROR_UNEXPECTED
+        );
+      }
+
+      type = types.queryElementAt(0, Ci.nsIContentPermissionType).type;
+      let combinedIntegration = Integration.contentPermission.getCombined(
+        ContentPermissionIntegration
+      );
+
+      let permissionPrompt = combinedIntegration.createPermissionPrompt(
+        type,
+        request
+      );
+      if (!permissionPrompt) {
+        throw Components.Exception(
+          `Failed to handle permission of type ${type}`,
+          Cr.NS_ERROR_FAILURE
+        );
+      }
+
+      permissionPrompt.prompt();
+    } catch (ex) {
+      Cu.reportError(ex);
+      request.cancel();
+      throw ex;
+    }
+
+    let schemeHistogram = Services.telemetry.getKeyedHistogramById(
+      "PERMISSION_REQUEST_ORIGIN_SCHEME"
+    );
+    let scheme = 0;
+    try {
+      if (request.principal.schemeIs("http")) {
+        scheme = 1;
+      } else if (request.principal.schemeIs("https")) {
+        scheme = 2;
+      }
+    } catch (ex) {
+      // If the request principal is not available at this point,
+      // the request has likely been cancelled before being shown to the
+      // user. We shouldn't record this request.
+      if (ex.result != Cr.NS_ERROR_FAILURE) {
+        Cu.reportError(ex);
+      }
+      return;
+    }
+    schemeHistogram.add(type, scheme);
+
+    let userInputHistogram = Services.telemetry.getKeyedHistogramById(
+      "PERMISSION_REQUEST_HANDLING_USER_INPUT"
+    );
+    userInputHistogram.add(type, request.isHandlingUserInput);
+  },
+};
+
+var DefaultBrowserCheck = {
+  prompt(win) {
+    let brandBundle = win.document.getElementById("bundle_brand");
+    let brandShortName = brandBundle.getString("brandShortName");
+
+    let shellBundle = win.document.getElementById("bundle_shell");
+    let buttonPrefix = "setDefaultBrowserAlert";
+    let yesButton = shellBundle.getFormattedString(
+      buttonPrefix + "Confirm.label",
+      [brandShortName]
+    );
+    let notNowButton = shellBundle.getString(buttonPrefix + "NotNow.label");
+
+    let promptTitle = shellBundle.getString("setDefaultBrowserTitle");
+    let promptMessage = shellBundle.getFormattedString(
+      "setDefaultBrowserMessage",
+      [brandShortName]
+    );
+    let askLabel = shellBundle.getFormattedString("setDefaultBrowserDontAsk", [
+      brandShortName,
+    ]);
+
+    let ps = Services.prompt;
+    let shouldAsk = { value: true };
+    let buttonFlags =
+      ps.BUTTON_TITLE_IS_STRING * ps.BUTTON_POS_0 +
+      ps.BUTTON_TITLE_IS_STRING * ps.BUTTON_POS_1 +
+      ps.BUTTON_POS_0_DEFAULT;
+    let rv = ps.confirmEx(
+      win,
+      promptTitle,
+      promptMessage,
+      buttonFlags,
+      yesButton,
+      notNowButton,
+      null,
+      askLabel,
+      shouldAsk
+    );
+    if (rv == 0) {
+      win.getShellService().setAsDefault();
+    } else if (!shouldAsk.value) {
+      win.getShellService().shouldCheckDefaultBrowser = false;
+    }
+
+    try {
+      let resultEnum = rv * 2 + shouldAsk.value;
+      Services.telemetry
+        .getHistogramById("BROWSER_SET_DEFAULT_RESULT")
+        .add(resultEnum);
+    } catch (ex) {
+      /* Don't break if Telemetry is acting up. */
+    }
+  },
+
+  /**
+   * Checks if the default browser check prompt will be shown.
+   * @param {boolean} isStartupCheck
+   *   If true, prefs will be set and telemetry will be recorded.
+   * @returns {boolean} True if the default browser check prompt will be shown.
+   */
+  async willCheckDefaultBrowser(isStartupCheck) {
+    let win = BrowserWindowTracker.getTopWindow();
+    let shellService = win.getShellService();
+
+    // Perform default browser checking.
+    if (!shellService) {
+      return false;
+    }
+
+    let shouldCheck =
+      !AppConstants.DEBUG &&
+      shellService.shouldCheckDefaultBrowser &&
+      !Services.prefs.getBoolPref(
+        "browser.defaultbrowser.notificationbar",
+        false
+      );
+
+    // Even if we shouldn't check the default browser, we still continue when
+    // isStartupCheck = true to set prefs and telemetry.
+    if (!shouldCheck && !isStartupCheck) {
+      return false;
+    }
+
+    // Skip the "Set Default Browser" check during first-run or after the
+    // browser has been run a few times.
+    const skipDefaultBrowserCheck =
+      Services.prefs.getBoolPref(
+        "browser.shell.skipDefaultBrowserCheckOnFirstRun"
+      ) &&
+      !Services.prefs.getBoolPref(
+        "browser.shell.didSkipDefaultBrowserCheckOnFirstRun"
+      );
+
+    let promptCount = Services.prefs.getIntPref(
+      "browser.shell.defaultBrowserCheckCount",
+      0
+    );
+
+    // If SessionStartup's state is not initialized, checking sessionType will set
+    // its internal state to "do not restore".
+    await SessionStartup.onceInitialized;
+    let willRecoverSession =
+      SessionStartup.sessionType == SessionStartup.RECOVER_SESSION;
+
+    // Don't show the prompt if we're already the default browser.
+    let isDefault = false;
+    let isDefaultError = false;
+    try {
+      isDefault = shellService.isDefaultBrowser(isStartupCheck, false);
+    } catch (ex) {
+      isDefaultError = true;
+    }
+
+    if (isDefault && isStartupCheck) {
+      let now = Math.floor(Date.now() / 1000).toString();
+      Services.prefs.setCharPref(
+        "browser.shell.mostRecentDateSetAsDefault",
+        now
+      );
+    }
+
+    let willPrompt = shouldCheck && !isDefault && !willRecoverSession;
+
+    if (willPrompt) {
+      if (skipDefaultBrowserCheck) {
+        if (isStartupCheck) {
+          Services.prefs.setBoolPref(
+            "browser.shell.didSkipDefaultBrowserCheckOnFirstRun",
+            true
+          );
+        }
+        willPrompt = false;
+      } else {
+        promptCount++;
+        if (isStartupCheck) {
+          Services.prefs.setIntPref(
+            "browser.shell.defaultBrowserCheckCount",
+            promptCount
+          );
+        }
+        if (!AppConstants.RELEASE_OR_BETA && promptCount > 3) {
+          willPrompt = false;
+        }
+      }
+    }
+
+    if (isStartupCheck) {
+      try {
+        // Report default browser status on startup to telemetry
+        // so we can track whether we are the default.
+        Services.telemetry
+          .getHistogramById("BROWSER_IS_USER_DEFAULT")
+          .add(isDefault);
+        Services.telemetry
+          .getHistogramById("BROWSER_IS_USER_DEFAULT_ERROR")
+          .add(isDefaultError);
+        Services.telemetry
+          .getHistogramById("BROWSER_SET_DEFAULT_ALWAYS_CHECK")
+          .add(shouldCheck);
+        Services.telemetry
+          .getHistogramById("BROWSER_SET_DEFAULT_DIALOG_PROMPT_RAWCOUNT")
+          .add(promptCount);
+      } catch (ex) {
+        /* Don't break the default prompt if telemetry is broken. */
+      }
+    }
+
+    return willPrompt;
+  },
+};
+
+/*
+ * Prompts users who have an outdated JAWS screen reader informing
+ * them they need to update JAWS or switch to esr. Can be removed
+ * 12/31/2018.
+ */
+var JawsScreenReaderVersionCheck = {
+  _prompted: false,
+
+  init() {
+    Services.obs.addObserver(this, "a11y-init-or-shutdown", true);
+  },
+
+  QueryInterface: ChromeUtils.generateQI([
+    "nsIObserver",
+    "nsISupportsWeakReference",
+  ]),
+
+  observe(subject, topic, data) {
+    if (topic == "a11y-init-or-shutdown" && data == "1") {
+      Services.tm.dispatchToMainThread(() => this._checkVersionAndPrompt());
+    }
+  },
+
+  onWindowsRestored() {
+    Services.tm.dispatchToMainThread(() => this._checkVersionAndPrompt());
+  },
+
+  _checkVersionAndPrompt() {
+    // Make sure we only prompt for versions of JAWS we do not
+    // support and never prompt if e10s is disabled or if we're on
+    // nightly.
+    if (
+      !Services.appinfo.shouldBlockIncompatJaws ||
+      !Services.appinfo.browserTabsRemoteAutostart ||
+      AppConstants.NIGHTLY_BUILD
+    ) {
+      return;
+    }
+
+    let win = BrowserWindowTracker.getTopWindow();
+    if (!win || !win.gBrowser || !win.gBrowser.selectedBrowser) {
+      Services.console.logStringMessage(
+        "Content access support for older versions of JAWS is disabled " +
+          "due to compatibility issues with this version of Firefox."
+      );
+      this._prompted = false;
+      return;
+    }
+
+    // Only prompt once per session
+    if (this._prompted) {
+      return;
+    }
+    this._prompted = true;
+
+    let browser = win.gBrowser.selectedBrowser;
+
+    // Prompt JAWS users to let them know they need to update
+    let promptMessage = win.gNavigatorBundle.getFormattedString(
+      "e10s.accessibilityNotice.jawsMessage",
+      [gBrandBundle.GetStringFromName("brandShortName")]
+    );
+    let notification;
+    // main option: an Ok button, keeps running with content accessibility disabled
+    let mainAction = {
+      label: win.gNavigatorBundle.getString(
+        "e10s.accessibilityNotice.acceptButton.label"
+      ),
+      accessKey: win.gNavigatorBundle.getString(
+        "e10s.accessibilityNotice.acceptButton.accesskey"
+      ),
+      callback() {
+        // If the user invoked the button option remove the notification,
+        // otherwise keep the alert icon around in the address bar.
+        notification.remove();
+      },
+    };
+    let options = {
+      popupIconURL: "chrome://browser/skin/e10s-64@2x.png",
+      persistWhileVisible: true,
+      persistent: true,
+      persistence: 100,
+    };
+
+    notification = win.PopupNotifications.show(
+      browser,
+      "e10s_enabled_with_incompat_jaws",
+      promptMessage,
+      null,
+      mainAction,
+      null,
+      options
+    );
+  },
+};
+
+/**
+ * AboutHomeStartupCache is responsible for reading and writing the
+ * initial about:home document from the HTTP cache as a startup
+ * performance optimization. It only works when the "privileged about
+ * content process" is enabled and when ENABLED_PREF is set to true.
+ *
+ * See https://firefox-source-docs.mozilla.org/browser/components/newtab/docs/v2-system-addon/about_home_startup_cache.html
+ * for further details.
+ */
+var AboutHomeStartupCache = {
+  ABOUT_HOME_URI_STRING: "about:home",
+  SCRIPT_EXTENSION: "script",
+  ENABLED_PREF: "browser.startup.homepage.abouthome_cache.enabled",
+  PRELOADED_NEWTAB_PREF: "browser.newtab.preload",
+  LOG_LEVEL_PREF: "browser.startup.homepage.abouthome_cache.loglevel",
+
+  // It's possible that the layout of about:home will change such that
+  // we want to invalidate any pre-existing caches. We do this by setting
+  // this meta key in the nsICacheEntry for the page.
+  //
+  // The version is currently set to the build ID, meaning that the cache
+  // is invalidated after every upgrade (like the main startup cache).
+  CACHE_VERSION_META_KEY: "version",
+
+  LOG_NAME: "AboutHomeStartupCache",
+
+  // These messages are used to request the "privileged about content process"
+  // to create the cached document, and then to receive that document.
+  CACHE_REQUEST_MESSAGE: "AboutHomeStartupCache:CacheRequest",
+  CACHE_RESPONSE_MESSAGE: "AboutHomeStartupCache:CacheResponse",
+  CACHE_USAGE_RESULT_MESSAGE: "AboutHomeStartupCache:UsageResult",
+
+  // When a "privileged about content process" is launched, this message is
+  // sent to give it some nsIInputStream's for the about:home document they
+  // should load.
+  SEND_STREAMS_MESSAGE: "AboutHomeStartupCache:InputStreams",
+
+  // This time in ms is used to debounce messages that are broadcast to
+  // all about:newtab's, or the preloaded about:newtab. We use those
+  // messages as a signal that it's likely time to refresh the cache.
+  CACHE_DEBOUNCE_RATE_MS: 5000,
+
+  // This is how long we'll block the AsyncShutdown while waiting for
+  // the cache to write. If we fail to write within that time, we will
+  // allow the shutdown to proceed.
+  SHUTDOWN_CACHE_WRITE_TIMEOUT_MS: 1000,
+
+  // The following values are as possible values for the
+  // browser.startup.abouthome_cache_result scalar. Keep these in sync with the
+  // scalar definition in Scalars.yaml. See setDeferredResult for more
+  // information.
+  CACHE_RESULT_SCALARS: {
+    UNSET: 0,
+    DOES_NOT_EXIST: 1,
+    CORRUPT_PAGE: 2,
+    CORRUPT_SCRIPT: 3,
+    INVALIDATED: 4,
+    LATE: 5,
+    VALID_AND_USED: 6,
+    DISABLED: 7,
+    NOT_LOADING_ABOUTHOME: 8,
+    PRELOADING_DISABLED: 9,
+  },
+
+  // This will be set to one of the values of CACHE_RESULT_SCALARS
+  // once it is determined which result best suits what occurred.
+  _cacheDeferredResultScalar: -1,
+
+  // A reference to the nsICacheEntry to read from and write to.
+  _cacheEntry: null,
+
+  // These nsIPipe's are sent down to the "privileged about content process"
+  // immediately after the process launches. This allows us to race the loading
+  // of the cache entry in the parent process with the load of the about:home
+  // page in the content process, since we'll connect the InputStream's to
+  // the pipes as soon as the nsICacheEntry is available.
+  //
+  // The page pipe is for the HTML markup for the page.
+  _pagePipe: null,
+  // The script pipe is for the JavaScript that the HTML markup loads
+  // to set its internal state.
+  _scriptPipe: null,
+  _cacheDeferred: null,
+
+  _enabled: false,
+  _initted: false,
+  _hasWrittenThisSession: false,
+  _finalized: false,
+  _firstPrivilegedProcessCreated: false,
+
+  init() {
+    if (this._initted) {
+      throw new Error("AboutHomeStartupCache already initted.");
+    }
+
+    this.setDeferredResult(this.CACHE_RESULT_SCALARS.UNSET);
+
+    this._enabled = Services.prefs.getBoolPref(this.ENABLED_PREF, false);
+
+    if (!this._enabled) {
+      this.recordResult(this.CACHE_RESULT_SCALARS.DISABLED);
+      return;
+    }
+
+    this.log = Log.repository.getLogger(this.LOG_NAME);
+    this.log.manageLevelFromPref(this.LOG_LEVEL_PREF);
+    this._appender = new Log.ConsoleAppender(new Log.BasicFormatter());
+    this.log.addAppender(this._appender);
+
+    this.log.trace("Initting.");
+
+    // If the user is not configured to load about:home at startup, then
+    // let's not bother with the cache - loading it needlessly is more likely
+    // to hinder what we're actually trying to load.
+    let willLoadAboutHome =
+      !HomePage.overridden &&
+      Services.prefs.getIntPref("browser.startup.page") === 1;
+
+    if (!willLoadAboutHome) {
+      this.log.trace("Not configured to load about:home by default.");
+      this.recordResult(this.CACHE_RESULT_SCALARS.NOT_LOADING_ABOUTHOME);
+      return;
+    }
+
+    if (!Services.prefs.getBoolPref(this.PRELOADED_NEWTAB_PREF, false)) {
+      this.log.trace("Preloaded about:newtab disabled.");
+      this.recordResult(this.CACHE_RESULT_SCALARS.PRELOADING_DISABLED);
+      return;
+    }
+
+    Services.obs.addObserver(this, "ipc:content-created");
+    Services.obs.addObserver(this, "process-type-set");
+    Services.obs.addObserver(this, "ipc:content-shutdown");
+    Services.obs.addObserver(this, "intl:app-locales-changed");
+
+    this.log.trace("Constructing pipes.");
+    this._pagePipe = this.makePipe();
+    this._scriptPipe = this.makePipe();
+
+    this._cacheEntryPromise = new Promise(resolve => {
+      this._cacheEntryResolver = resolve;
+    });
+
+    let lci = Services.loadContextInfo.default;
+    let storage = Services.cache2.diskCacheStorage(lci, false);
+    try {
+      storage.asyncOpenURI(
+        this.aboutHomeURI,
+        "",
+        Ci.nsICacheStorage.OPEN_PRIORITY,
+        this
+      );
+    } catch (e) {
+      this.log.error("Failed to open about:home cache entry", e);
+    }
+
+    this._cacheTask = new DeferredTask(async () => {
+      await this.cacheNow();
+    }, this.CACHE_DEBOUNCE_RATE_MS);
+
+    AsyncShutdown.quitApplicationGranted.addBlocker(
+      "AboutHomeStartupCache: Writing cache",
+      async () => {
+        await this.onShutdown();
+      },
+      () => this._cacheProgress
+    );
+
+    this._cacheDeferred = null;
+    this._initted = true;
+    this.log.trace("Initialized.");
+  },
+
+  get initted() {
+    return this._initted;
+  },
+
+  uninit() {
+    if (!this._enabled) {
+      return;
+    }
+
+    try {
+      Services.obs.removeObserver(this, "ipc:content-created");
+      Services.obs.removeObserver(this, "process-type-set");
+      Services.obs.removeObserver(this, "ipc:content-shutdown");
+      Services.obs.removeObserver(this, "intl:app-locales-changed");
+    } catch (e) {
+      // If we failed to initialize and register for these observer
+      // notifications, then attempting to remove them will throw.
+      // It's fine to ignore that case on shutdown.
+    }
+
+    if (this._cacheTask) {
+      this._cacheTask.disarm();
+      this._cacheTask = null;
+    }
+
+    this._pagePipe = null;
+    this._scriptPipe = null;
+    this._initted = false;
+    this._cacheEntry = null;
+    this._hasWrittenThisSession = false;
+    this._cacheEntryPromise = null;
+    this._cacheEntryResolver = null;
+    this._cacheDeferredResultScalar = -1;
+
+    if (this.log) {
+      this.log.trace("Uninitialized.");
+      this.log.removeAppender(this._appender);
+      this.log = null;
+    }
+
+    this._procManager = null;
+    this._procManagerID = null;
+    this._appender = null;
+    this._cacheDeferred = null;
+    this._finalized = false;
+    this._firstPrivilegedProcessCreated = false;
+  },
+
+  _aboutHomeURI: null,
+
+  get aboutHomeURI() {
+    if (this._aboutHomeURI) {
+      return this._aboutHomeURI;
+    }
+
+    this._aboutHomeURI = Services.io.newURI(this.ABOUT_HOME_URI_STRING);
+    return this._aboutHomeURI;
+  },
+
+  // For the AsyncShutdown blocker, this is used to populate the progress
+  // value.
+  _cacheProgress: "Not yet begun",
+
+  /**
+   * Called by the AsyncShutdown blocker on quit-application-granted
+   * to potentially flush the most recent cache to disk. If one was
+   * never written during the session, one is generated and written
+   * before the async function resolves.
+   *
+   * @param withTimeout (boolean)
+   *   Whether or not the timeout mechanism should be used. Defaults
+   *   to true.
+   * @returns Promise
+   * @resolves boolean
+   *   If a cache has never been written, or a cache write is in
+   *   progress, resolves true when the cache has been written. Also
+   *   resolves to true if a cache didn't need to be written.
+   *
+   *   Resolves to false if a cache write unexpectedly timed out.
+   */
+  async onShutdown(withTimeout = true) {
+    // If we never wrote this session, arm the task so that the next
+    // step can finalize.
+    if (!this._hasWrittenThisSession) {
+      this.log.trace("Never wrote a cache this session. Arming cache task.");
+      this._cacheTask.arm();
+    }
+
+    Services.telemetry.scalarSet(
+      "browser.startup.abouthome_cache_shutdownwrite",
+      this._cacheTask.isArmed
+    );
+
+    if (this._cacheTask.isArmed) {
+      this.log.trace("Finalizing cache task on shutdown");
+      this._finalized = true;
+
+      // To avoid hanging shutdowns, we'll ensure that we wait a maximum of
+      // SHUTDOWN_CACHE_WRITE_TIMEOUT_MS millseconds before giving up.
+      let { setTimeout, clearTimeout } = ChromeUtils.import(
+        "resource://gre/modules/Timer.jsm"
+      );
+
+      const TIMED_OUT = Symbol();
+      let timeoutID = 0;
+
+      let timeoutPromise = new Promise(resolve => {
+        timeoutID = setTimeout(
+          () => resolve(TIMED_OUT),
+          this.SHUTDOWN_CACHE_WRITE_TIMEOUT_MS
+        );
+      });
+
+      let promises = [this._cacheTask.finalize()];
+      if (withTimeout) {
+        this.log.trace("Using timeout mechanism.");
+        promises.push(timeoutPromise);
+      } else {
+        this.log.trace("Skipping timeout mechanism.");
+      }
+
+      let result = await Promise.race(promises);
+      this.log.trace("Done blocking shutdown.");
+      clearTimeout(timeoutID);
+      if (result === TIMED_OUT) {
+        this.log.error("Timed out getting cache streams. Skipping cache task.");
+        return false;
+      }
+    }
+    this.log.trace("onShutdown is exiting");
+    return true;
+  },
+
+  /**
+   * Called by the _cacheTask DeferredTask to actually do the work of
+   * caching the about:home document.
+   *
+   * @returns Promise
+   * @resolves undefined
+   *   Resolves when a fresh version of the cache has been written.
+   */
+  async cacheNow() {
+    this.log.trace("Caching now.");
+    this._cacheProgress = "Getting cache streams";
+
+    let { pageInputStream, scriptInputStream } = await this.requestCache();
+
+    if (!pageInputStream || !scriptInputStream) {
+      this.log.trace("Failed to get cache streams.");
+      this._cacheProgress = "Failed to get streams";
+      return;
+    }
+
+    this.log.trace("Got cache streams.");
+
+    this._cacheProgress = "Writing to cache";
+
+    try {
+      this.log.trace("Populating cache.");
+      await this.populateCache(pageInputStream, scriptInputStream);
+    } catch (e) {
+      this._cacheProgress = "Failed to populate cache";
+      this.log.error("Populating the cache failed: ", e);
+      return;
+    }
+
+    this._cacheProgress = "Done";
+    this.log.trace("Done writing to cache.");
+    this._hasWrittenThisSession = true;
+  },
+
+  /**
+   * Requests the cached document streams from the "privileged about content
+   * process".
+   *
+   * @returns Promise
+   * @resolves Object
+   *   Resolves with an Object with the following properties:
+   *
+   *   pageInputStream (nsIInputStream)
+   *     The page content to write to the cache, or null if request the streams
+   *     failed.
+   *
+   *   scriptInputStream (nsIInputStream)
+   *     The script content to write to the cache, or null if request the streams
+   *     failed.
+   */
+  requestCache() {
+    this.log.trace("Parent is requesting Activity Stream state object.");
+    if (!this._procManager) {
+      this.log.error("requestCache called with no _procManager!");
+      return { pageInputStream: null, scriptInputStream: null };
+    }
+
+    if (this._procManager.remoteType != E10SUtils.PRIVILEGEDABOUT_REMOTE_TYPE) {
+      this.log.error("Somehow got the wrong process type.");
+      return { pageInputStream: null, scriptInputStream: null };
+    }
+
+    let state = AboutNewTab.activityStream.store.getState();
+    return new Promise(resolve => {
+      this._cacheDeferred = resolve;
+      this.log.trace("Parent is requesting cache streams.");
+      this._procManager.sendAsyncMessage(this.CACHE_REQUEST_MESSAGE, { state });
+    });
+  },
+
+  /**
+   * Helper function that returns a newly constructed nsIPipe instance.
+   *
+   * @return nsIPipe
+   */
+  makePipe() {
+    let pipe = Cc["@mozilla.org/pipe;1"].createInstance(Ci.nsIPipe);
+    pipe.init(
+      true /* non-blocking input */,
+      true /* non-blocking output */,
+      0 /* segment size */,
+      0 /* max segments */
+    );
+    return pipe;
+  },
+
+  get pagePipe() {
+    return this._pagePipe;
+  },
+
+  get scriptPipe() {
+    return this._scriptPipe;
+  },
+
+  /**
+   * Called when the nsICacheEntry has been accessed. If the nsICacheEntry
+   * has content that we want to send down to the "privileged about content
+   * process", then we connect that content to the nsIPipe's that may or
+   * may not have already been sent down to the process.
+   *
+   * In the event that the nsICacheEntry doesn't contain anything usable,
+   * the nsInputStreams on the nsIPipe's are closed.
+   */
+  connectToPipes() {
+    this.log.trace(`Connecting nsICacheEntry to pipes.`);
+
+    // If the cache doesn't yet exist, we'll know because the version metadata
+    // won't exist yet.
+    let version;
+    try {
+      this.log.trace("");
+      version = this._cacheEntry.getMetaDataElement(
+        this.CACHE_VERSION_META_KEY
+      );
+    } catch (e) {
+      if (e.result == Cr.NS_ERROR_NOT_AVAILABLE) {
+        this.log.debug("Cache meta data does not exist. Closing streams.");
+        this.pagePipe.outputStream.close();
+        this.scriptPipe.outputStream.close();
+        this.setDeferredResult(this.CACHE_RESULT_SCALARS.DOES_NOT_EXIST);
+        return;
+      }
+
+      throw e;
+    }
+
+    this.log.info("Version retrieved is", version);
+
+    if (version != Services.appinfo.appBuildID) {
+      this.log.info("Version does not match! Dooming and closing streams.\n");
+      // This cache is no good - doom it, and prepare for a new one.
+      this.clearCache();
+      this.pagePipe.outputStream.close();
+      this.scriptPipe.outputStream.close();
+      this.setDeferredResult(this.CACHE_RESULT_SCALARS.INVALIDATED);
+      return;
+    }
+
+    let cachePageInputStream;
+
+    try {
+      cachePageInputStream = this._cacheEntry.openInputStream(0);
+    } catch (e) {
+      this.log.error("Failed to open main input stream for cache entry", e);
+      this.pagePipe.outputStream.close();
+      this.scriptPipe.outputStream.close();
+      this.setDeferredResult(this.CACHE_RESULT_SCALARS.CORRUPT_PAGE);
+      return;
+    }
+
+    this.log.trace("Connecting page stream to pipe.");
+    NetUtil.asyncCopy(cachePageInputStream, this.pagePipe.outputStream, () => {
+      this.log.info("Page stream connected to pipe.");
+    });
+
+    let cacheScriptInputStream;
+    try {
+      this.log.trace("Connecting script stream to pipe.");
+      cacheScriptInputStream = this._cacheEntry.openAlternativeInputStream(
+        "script"
+      );
+      NetUtil.asyncCopy(
+        cacheScriptInputStream,
+        this.scriptPipe.outputStream,
+        () => {
+          this.log.info("Script stream connected to pipe.");
+        }
+      );
+    } catch (e) {
+      if (e.result == Cr.NS_ERROR_NOT_AVAILABLE) {
+        // For some reason, the script was not available. We'll close the pipe
+        // without sending anything into it. The privileged about content process
+        // will notice that there's nothing available in the pipe, and fall back
+        // to dynamically generating the page.
+        this.log.error("Script stream not available! Closing pipe.");
+        this.scriptPipe.outputStream.close();
+        this.setDeferredResult(this.CACHE_RESULT_SCALARS.CORRUPT_SCRIPT);
+      } else {
+        throw e;
+      }
+    }
+
+    this.setDeferredResult(this.CACHE_RESULT_SCALARS.VALID_AND_USED);
+    this.log.trace("Streams connected to pipes.");
+  },
+
+  /**
+   * Called when we have received a the cache values from the "privileged
+   * about content process". The page and script streams are written to
+   * the nsICacheEntry.
+   *
+   * This writing is asynchronous, and if a write happens to already be
+   * underway when this function is called, that latter call will be
+   * ignored.
+   *
+   * @param pageInputStream (nsIInputStream)
+   *   A stream containing the HTML markup to be saved to the cache.
+   * @param scriptInputStream (nsIInputStream)
+   *   A stream containing the JS hydration script to be saved to the cache.
+   * @returns Promise
+   * @resolves undefined
+   *   When the cache has been successfully written to.
+   * @rejects Error
+   *   Rejects with a JS Error if writing any part of the cache happens to
+   *   fail.
+   */
+  async populateCache(pageInputStream, scriptInputStream) {
+    await this.ensureCacheEntry();
+
+    await new Promise((resolve, reject) => {
+      // Doom the old cache entry, so we can start writing to a new one.
+      this.log.trace("Populating the cache. Dooming old entry.");
+      this.clearCache();
+
+      this.log.trace("Opening the page output stream.");
+      let pageOutputStream;
+      try {
+        pageOutputStream = this._cacheEntry.openOutputStream(0, -1);
+      } catch (e) {
+        reject(e);
+        return;
+      }
+
+      this.log.info("Writing the page cache.");
+      NetUtil.asyncCopy(pageInputStream, pageOutputStream, pageResult => {
+        if (!Components.isSuccessCode(pageResult)) {
+          this.log.error("Failed to write page. Result: " + pageResult);
+          reject(new Error(pageResult));
+          return;
+        }
+
+        this.log.trace(
+          "Writing the page data is complete. Now opening the " +
+            "script output stream."
+        );
+
+        let scriptOutputStream;
+        try {
+          scriptOutputStream = this._cacheEntry.openAlternativeOutputStream(
+            "script",
+            -1
+          );
+        } catch (e) {
+          reject(e);
+          return;
+        }
+
+        this.log.info("Writing the script cache.");
+        NetUtil.asyncCopy(
+          scriptInputStream,
+          scriptOutputStream,
+          scriptResult => {
+            if (!Components.isSuccessCode(scriptResult)) {
+              this.log.error("Failed to write script. Result: " + scriptResult);
+              reject(new Error(scriptResult));
+              return;
+            }
+
+            this.log.trace(
+              "Writing the script cache is done. Setting version."
+            );
+            try {
+              this._cacheEntry.setMetaDataElement(
+                "version",
+                Services.appinfo.appBuildID
+              );
+            } catch (e) {
+              this.log.error("Failed to write version.");
+              reject(e);
+              return;
+            }
+            this.log.trace(`Version is set to ${Services.appinfo.appBuildID}.`);
+            this.log.info("Caching of page and script is done.");
+            resolve();
+          }
+        );
+      });
+    });
+
+    this.log.trace("populateCache has finished.");
+  },
+
+  /**
+   * Returns a Promise that resolves once the nsICacheEntry for the cache
+   * is available to write to and read from.
+   *
+   * @returns Promise
+   * @resolves nsICacheEntry
+   *   Once the cache entry has become available.
+   * @rejects String
+   *   Rejects with an error message if getting the cache entry is attempted
+   *   before the AboutHomeStartupCache component has been initialized.
+   */
+  ensureCacheEntry() {
+    if (!this._initted) {
+      return Promise.reject(
+        "Cannot ensureCacheEntry - AboutHomeStartupCache is not initted"
+      );
+    }
+
+    return this._cacheEntryPromise;
+  },
+
+  /**
+   * Clears the contents of the cache.
+   */
+  clearCache() {
+    this.log.trace("Clearing the cache.");
+    this._cacheEntry = this._cacheEntry.recreate();
+    this._cacheEntryPromise = new Promise(resolve => {
+      resolve(this._cacheEntry);
+    });
+    this._hasWrittenThisSession = false;
+  },
+
+  /**
+   * Called when a content process is created. If this is the "privileged
+   * about content process", then the cache streams will be sent to it.
+   *
+   * @param childID (Number)
+   *   The unique ID for the content process that was created, as passed by
+   *   ipc:content-created.
+   * @param procManager (ProcessMessageManager)
+   *   The ProcessMessageManager for the created content process.
+   * @param processParent
+   *   The nsIDOMProcessParent for the tab.
+   */
+  onContentProcessCreated(childID, procManager, processParent) {
+    if (procManager.remoteType == E10SUtils.PRIVILEGEDABOUT_REMOTE_TYPE) {
+      if (this._finalized) {
+        this.log.trace(
+          "Ignoring privileged about content process launch after finalization."
+        );
+        return;
+      }
+
+      if (this._firstPrivilegedProcessCreated) {
+        this.log.trace(
+          "Ignoring non-first privileged about content processes."
+        );
+        return;
+      }
+
+      this.log.trace(
+        `A privileged about content process is launching with ID ${childID}.`
+      );
+
+      this.log.info("Sending input streams down to content process.");
+      let actor = processParent.getActor("BrowserProcess");
+      actor.sendAsyncMessage(this.SEND_STREAMS_MESSAGE, {
+        pageInputStream: this.pagePipe.inputStream,
+        scriptInputStream: this.scriptPipe.inputStream,
+      });
+
+      procManager.addMessageListener(this.CACHE_RESPONSE_MESSAGE, this);
+      procManager.addMessageListener(this.CACHE_USAGE_RESULT_MESSAGE, this);
+      this._procManager = procManager;
+      this._procManagerID = childID;
+      this._firstPrivilegedProcessCreated = true;
+    }
+  },
+
+  /**
+   * Called when a content process is destroyed. Either it shut down normally,
+   * or it crashed. If this is the "privileged about content process", then some
+   * internal state is cleared.
+   *
+   * @param childID (Number)
+   *   The unique ID for the content process that was created, as passed by
+   *   ipc:content-shutdown.
+   */
+  onContentProcessShutdown(childID) {
+    this.log.info(`Content process shutdown: ${childID}`);
+    if (this._procManagerID == childID) {
+      this.log.info("It was the current privileged about process.");
+      if (this._cacheDeferred) {
+        this.log.error(
+          "A privileged about content process shut down while cache streams " +
+            "were still en route."
+        );
+        // The crash occurred while we were waiting on cache input streams to
+        // be returned to us. Resolve with null streams instead.
+        this._cacheDeferred({ pageInputStream: null, scriptInputStream: null });
+        this._cacheDeferred = null;
+      }
+
+      this._procManager.removeMessageListener(
+        this.CACHE_RESPONSE_MESSAGE,
+        this
+      );
+      this._procManager.removeMessageListener(
+        this.CACHE_USAGE_RESULT_MESSAGE,
+        this
+      );
+      this._procManager = null;
+      this._procManagerID = null;
+    }
+  },
+
+  /**
+   * Called externally by ActivityStreamMessageChannel anytime
+   * a message is broadcast to all about:newtabs, or sent to the
+   * preloaded about:newtab. This is used to determine if we need
+   * to refresh the cache.
+   */
+  onPreloadedNewTabMessage() {
+    if (!this._initted || !this._enabled) {
+      return;
+    }
+
+    if (this._finalized) {
+      this.log.trace("Ignoring preloaded newtab update after finalization.");
+      return;
+    }
+
+    this.log.trace("Preloaded about:newtab was updated.");
+
+    this._cacheTask.disarm();
+    this._cacheTask.arm();
+  },
+
+  /**
+   * Stores the CACHE_RESULT_SCALARS value that most accurately represents
+   * the current notion of how the cache has operated so far. It is stored
+   * temporarily like this because we need to hear from the privileged
+   * about content process to hear whether or not retrieving the cache
+   * actually worked on that end. The success state reported back from
+   * the privileged about content process will be compared against the
+   * deferred result scalar to compute what will be recorded to
+   * Telemetry.
+   *
+   * Note that this value will only be recorded if its value is GREATER
+   * than the currently recorded value. This is because it's possible for
+   * certain functions that record results to re-enter - but we want to record
+   * the _first_ condition that caused the cache to not be read from.
+   *
+   * @param result (Number)
+   *   One of the CACHE_RESULT_SCALARS values. If this value is less than
+   *   the currently recorded value, it is ignored.
+   */
+  setDeferredResult(result) {
+    if (this._cacheDeferredResultScalar < result) {
+      this._cacheDeferredResultScalar = result;
+    }
+  },
+
+  /**
+   * Records the final result of how the cache operated for the user
+   * during this session to Telemetry.
+   */
+  recordResult(result) {
+    // Note: this can be called very early on in the lifetime of
+    // AboutHomeStartupCache, so things like this.log might not exist yet.
+    Services.telemetry.scalarSet(
+      "browser.startup.abouthome_cache_result",
+      result
+    );
+  },
+
+  /**
+   * Called when the parent process receives a message from the privileged
+   * about content process saying whether or not reading from the cache
+   * was successful.
+   *
+   * @param success (boolean)
+   *   True if reading from the cache succeeded.
+   */
+  onUsageResult(success) {
+    this.log.trace(`Received usage result. Success = ${success}`);
+    if (success) {
+      if (
+        this._cacheDeferredResultScalar !=
+        this.CACHE_RESULT_SCALARS.VALID_AND_USED
+      ) {
+        this.log.error(
+          "Somehow got a success result despite having never " +
+            "successfully sent down the cache streams"
+        );
+        this.recordResult(this._cacheDeferredResultScalar);
+      } else {
+        this.recordResult(this.CACHE_RESULT_SCALARS.VALID_AND_USED);
+      }
+
+      return;
+    }
+
+    if (
+      this._cacheDeferredResultScalar ==
+      this.CACHE_RESULT_SCALARS.VALID_AND_USED
+    ) {
+      // We failed to read from the cache despite having successfully
+      // sent it down to the content process. We presume then that the
+      // streams just didn't provide any bytes in time.
+      this.recordResult(this.CACHE_RESULT_SCALARS.LATE);
+    } else {
+      // We failed to read the cache, but already knew why. We can
+      // now record that value.
+      this.recordResult(this._cacheDeferredResultScalar);
+    }
+  },
+
+  QueryInterface: ChromeUtils.generateQI([
+    "nsICacheEntryOpenallback",
+    "nsIObserver",
+  ]),
+
+  /** MessageListener **/
+
+  receiveMessage(message) {
+    // Only the privileged about content process can write to the cache.
+    if (message.target.remoteType != E10SUtils.PRIVILEGEDABOUT_REMOTE_TYPE) {
+      this.log.error(
+        "Received a message from a non-privileged content process!"
+      );
+      return;
+    }
+
+    switch (message.name) {
+      case this.CACHE_RESPONSE_MESSAGE: {
+        this.log.trace("Parent received cache streams.");
+        if (!this._cacheDeferred) {
+          this.log.error("Parent doesn't have _cacheDeferred set up!");
+          return;
+        }
+
+        this._cacheDeferred(message.data);
+        this._cacheDeferred = null;
+        break;
+      }
+      case this.CACHE_USAGE_RESULT_MESSAGE: {
+        this.onUsageResult(message.data.success);
+        break;
+      }
+    }
+  },
+
+  /** nsIObserver **/
+
+  observe(aSubject, aTopic, aData) {
+    switch (aTopic) {
+      case "intl:app-locales-changed": {
+        this.clearCache();
+        break;
+      }
+      case "process-type-set":
+      // Intentional fall-through
+      case "ipc:content-created": {
+        let childID = aData;
+        let procManager = aSubject
+          .QueryInterface(Ci.nsIInterfaceRequestor)
+          .getInterface(Ci.nsIMessageSender);
+        let pp = aSubject.QueryInterface(Ci.nsIDOMProcessParent);
+        this.onContentProcessCreated(childID, procManager, pp);
+        break;
+      }
+
+      case "ipc:content-shutdown": {
+        let childID = aData;
+        this.onContentProcessShutdown(childID);
+        break;
+      }
+    }
+  },
+
+  /** nsICacheEntryOpenCallback **/
+
+  onCacheEntryCheck(aEntry, aApplicationCache) {
+    return Ci.nsICacheEntryOpenCallback.ENTRY_WANTED;
+  },
+
+  onCacheEntryAvailable(aEntry, aNew, aApplicationCache, aResult) {
+    this.log.trace("Cache entry is available.");
+
+    this._cacheEntry = aEntry;
+    this.connectToPipes();
+    this._cacheEntryResolver(this._cacheEntry);
+  },
+};