Remove Pale Moon from the Unified XUL Platform repository

Development will proceed at https://github.com/MoonchildProductions/Pale-Moon

1 files changed, 0 insertions, 4786 deletions

diff --git a/application/palemoon/components/sessionstore/SessionStore.jsm b/application/palemoon/components/sessionstore/SessionStore.jsm
deleted file mode 100644
index e19a578f4..000000000
--- a/application/palemoon/components/sessionstore/SessionStore.jsm
+++ /dev/null
@@ -1,4786 +0,0 @@
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this file,
- * You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-this.EXPORTED_SYMBOLS = ["SessionStore"];
-
-const Cu = Components.utils;
-const Cc = Components.classes;
-const Ci = Components.interfaces;
-const Cr = Components.results;
-
-const STATE_STOPPED = 0;
-const STATE_RUNNING = 1;
-const STATE_QUITTING = -1;
-
-const STATE_STOPPED_STR = "stopped";
-const STATE_RUNNING_STR = "running";
-
-const TAB_STATE_NEEDS_RESTORE = 1;
-const TAB_STATE_RESTORING = 2;
-
-const PRIVACY_NONE = 0;
-const PRIVACY_ENCRYPTED = 1;
-const PRIVACY_FULL = 2;
-
-const NOTIFY_WINDOWS_RESTORED = "sessionstore-windows-restored";
-const NOTIFY_BROWSER_STATE_RESTORED = "sessionstore-browser-state-restored";
-
-// Default maximum number of tabs to restore simultaneously. Controlled by
-// the browser.sessionstore.max_concurrent_tabs pref.
-const DEFAULT_MAX_CONCURRENT_TAB_RESTORES = 3;
-
-// global notifications observed
-const OBSERVING = [
-  "domwindowopened", "domwindowclosed",
-  "quit-application-requested", "quit-application-granted",
-  "browser-lastwindow-close-granted",
-  "quit-application", "browser:purge-session-history",
-  "browser:purge-domain-data"
-];
-
-// XUL Window properties to (re)store
-// Restored in restoreDimensions()
-const WINDOW_ATTRIBUTES = ["width", "height", "screenX", "screenY", "sizemode"];
-
-// Hideable window features to (re)store
-// Restored in restoreWindowFeatures()
-const WINDOW_HIDEABLE_FEATURES = [
-  "menubar", "toolbar", "locationbar", "personalbar", "statusbar", "scrollbars"
-];
-
-const MESSAGES = [
-  // The content script tells us that its form data (or that of one of its
-  // subframes) might have changed. This can be the contents or values of
-  // standard form fields or of ContentEditables.
-  "SessionStore:input",
-
-  // The content script has received a pageshow event. This happens when a
-  // page is loaded from bfcache without any network activity, i.e. when
-  // clicking the back or forward button.
-  "SessionStore:pageshow"
-];
-
-// These are tab events that we listen to.
-const TAB_EVENTS = [
-  "TabOpen", "TabClose", "TabSelect", "TabShow", "TabHide", "TabPinned",
-  "TabUnpinned"
-];
-
-#ifndef XP_WIN
-#define BROKEN_WM_Z_ORDER
-#endif
-
-Cu.import("resource://gre/modules/Services.jsm", this);
-Cu.import("resource://gre/modules/XPCOMUtils.jsm", this);
-// debug.js adds NS_ASSERT. cf. bug 669196
-Cu.import("resource://gre/modules/debug.js", this);
-Cu.import("resource://gre/modules/osfile.jsm", this);
-Cu.import("resource://gre/modules/PrivateBrowsingUtils.jsm", this);
-Cu.import("resource://gre/modules/Promise.jsm", this);
-
-XPCOMUtils.defineLazyServiceGetter(this, "gSessionStartup",
-  "@mozilla.org/browser/sessionstartup;1", "nsISessionStartup");
-XPCOMUtils.defineLazyServiceGetter(this, "gScreenManager",
-  "@mozilla.org/gfx/screenmanager;1", "nsIScreenManager");
-
-// List of docShell capabilities to (re)store. These are automatically
-// retrieved from a given docShell if not already collected before.
-// This is made so they're automatically in sync with all nsIDocShell.allow*
-// properties.
-var gDocShellCapabilities = (function () {
-  let caps;
-
-  return docShell => {
-    if (!caps) {
-      let keys = Object.keys(docShell);
-      caps = keys.filter(k => k.startsWith("allow")).map(k => k.slice(5));
-    }
-
-    return caps;
-  };
-})();
-
-XPCOMUtils.defineLazyModuleGetter(this, "NetUtil",
-  "resource://gre/modules/NetUtil.jsm");
-
-#ifdef MOZ_DEVTOOLS
-XPCOMUtils.defineLazyModuleGetter(this, "ScratchpadManager",
-  "resource://devtools/client/scratchpad/scratchpad-manager.jsm");
-
-Object.defineProperty(this, "HUDService", {
-  get: function HUDService_getter() {
-    let devtools = Cu.import("resource://devtools/shared/Loader.jsm", {}).devtools;
-    return devtools.require("devtools/client/webconsole/hudservice").HUDService;
-  },
-  configurable: true,
-  enumerable: true
-});
-#endif  
-  
-XPCOMUtils.defineLazyModuleGetter(this, "DocumentUtils",
-  "resource:///modules/sessionstore/DocumentUtils.jsm");
-XPCOMUtils.defineLazyModuleGetter(this, "SessionStorage",
-  "resource:///modules/sessionstore/SessionStorage.jsm");
-XPCOMUtils.defineLazyModuleGetter(this, "_SessionFile",
-  "resource:///modules/sessionstore/_SessionFile.jsm");
-
-function debug(aMsg) {
-  aMsg = ("SessionStore: " + aMsg).replace(/\S{80}/g, "$&\n");
-  Services.console.logStringMessage(aMsg);
-}
-
-this.SessionStore = {
-  get promiseInitialized() {
-    return SessionStoreInternal.promiseInitialized.promise;
-  },
-
-  get canRestoreLastSession() {
-    return SessionStoreInternal.canRestoreLastSession;
-  },
-
-  set canRestoreLastSession(val) {
-    SessionStoreInternal.canRestoreLastSession = val;
-  },
-
-  init: function ss_init(aWindow) {
-    return SessionStoreInternal.init(aWindow);
-  },
-
-  getBrowserState: function ss_getBrowserState() {
-    return SessionStoreInternal.getBrowserState();
-  },
-
-  setBrowserState: function ss_setBrowserState(aState) {
-    SessionStoreInternal.setBrowserState(aState);
-  },
-
-  getWindowState: function ss_getWindowState(aWindow) {
-    return SessionStoreInternal.getWindowState(aWindow);
-  },
-
-  setWindowState: function ss_setWindowState(aWindow, aState, aOverwrite) {
-    SessionStoreInternal.setWindowState(aWindow, aState, aOverwrite);
-  },
-
-  getTabState: function ss_getTabState(aTab) {
-    return SessionStoreInternal.getTabState(aTab);
-  },
-
-  setTabState: function ss_setTabState(aTab, aState) {
-    SessionStoreInternal.setTabState(aTab, aState);
-  },
-
-  duplicateTab: function ss_duplicateTab(aWindow, aTab, aDelta) {
-    return SessionStoreInternal.duplicateTab(aWindow, aTab, aDelta);
-  },
-
-  getClosedTabCount: function ss_getClosedTabCount(aWindow) {
-    return SessionStoreInternal.getClosedTabCount(aWindow);
-  },
-
-  getClosedTabData: function ss_getClosedTabDataAt(aWindow) {
-    return SessionStoreInternal.getClosedTabData(aWindow);
-  },
-
-  undoCloseTab: function ss_undoCloseTab(aWindow, aIndex) {
-    return SessionStoreInternal.undoCloseTab(aWindow, aIndex);
-  },
-
-  forgetClosedTab: function ss_forgetClosedTab(aWindow, aIndex) {
-    return SessionStoreInternal.forgetClosedTab(aWindow, aIndex);
-  },
-
-  getClosedWindowCount: function ss_getClosedWindowCount() {
-    return SessionStoreInternal.getClosedWindowCount();
-  },
-
-  getClosedWindowData: function ss_getClosedWindowData() {
-    return SessionStoreInternal.getClosedWindowData();
-  },
-
-  undoCloseWindow: function ss_undoCloseWindow(aIndex) {
-    return SessionStoreInternal.undoCloseWindow(aIndex);
-  },
-
-  forgetClosedWindow: function ss_forgetClosedWindow(aIndex) {
-    return SessionStoreInternal.forgetClosedWindow(aIndex);
-  },
-
-  getWindowValue: function ss_getWindowValue(aWindow, aKey) {
-    return SessionStoreInternal.getWindowValue(aWindow, aKey);
-  },
-
-  setWindowValue: function ss_setWindowValue(aWindow, aKey, aStringValue) {
-    SessionStoreInternal.setWindowValue(aWindow, aKey, aStringValue);
-  },
-
-  deleteWindowValue: function ss_deleteWindowValue(aWindow, aKey) {
-    SessionStoreInternal.deleteWindowValue(aWindow, aKey);
-  },
-
-  getTabValue: function ss_getTabValue(aTab, aKey) {
-    return SessionStoreInternal.getTabValue(aTab, aKey);
-  },
-
-  setTabValue: function ss_setTabValue(aTab, aKey, aStringValue) {
-    SessionStoreInternal.setTabValue(aTab, aKey, aStringValue);
-  },
-
-  deleteTabValue: function ss_deleteTabValue(aTab, aKey) {
-    SessionStoreInternal.deleteTabValue(aTab, aKey);
-  },
-
-  persistTabAttribute: function ss_persistTabAttribute(aName) {
-    SessionStoreInternal.persistTabAttribute(aName);
-  },
-
-  restoreLastSession: function ss_restoreLastSession() {
-    SessionStoreInternal.restoreLastSession();
-  },
-
-  checkPrivacyLevel: function ss_checkPrivacyLevel(aIsHTTPS, aUseDefaultPref) {
-    return SessionStoreInternal.checkPrivacyLevel(aIsHTTPS, aUseDefaultPref);
-  }
-};
-
-// Freeze the SessionStore object. We don't want anyone to modify it.
-Object.freeze(SessionStore);
-
-var SessionStoreInternal = {
-  QueryInterface: XPCOMUtils.generateQI([
-    Ci.nsIDOMEventListener,
-    Ci.nsIObserver,
-    Ci.nsISupportsWeakReference
-  ]),
-
-  // set default load state
-  _loadState: STATE_STOPPED,
-
-  // During the initial restore and setBrowserState calls tracks the number of
-  // windows yet to be restored
-  _restoreCount: -1,
-
-  // whether a setBrowserState call is in progress
-  _browserSetState: false,
-
-  // time in milliseconds (Date.now()) when the session was last written to file
-  _lastSaveTime: 0,
-
-  // time in milliseconds when the session was started (saved across sessions),
-  // defaults to now if no session was restored or timestamp doesn't exist
-  _sessionStartTime: Date.now(),
-
-  // states for all currently opened windows
-  _windows: {},
-
-  // internal states for all open windows (data we need to associate,
-  // but not write to disk)
-  _internalWindows: {},
-
-  // states for all recently closed windows
-  _closedWindows: [],
-
-  // not-"dirty" windows usually don't need to have their data updated
-  _dirtyWindows: {},
-
-  // collection of session states yet to be restored
-  _statesToRestore: {},
-
-  // counts the number of crashes since the last clean start
-  _recentCrashes: 0,
-
-  // whether the last window was closed and should be restored
-  _restoreLastWindow: false,
-
-  // number of tabs currently restoring
-  _tabsRestoringCount: 0,
-  
-  // max number of tabs to restore concurrently
-  _maxConcurrentTabRestores: DEFAULT_MAX_CONCURRENT_TAB_RESTORES,
-  
-  // whether restored tabs load cached versions or force a reload
-  _cacheBehavior: 0,
-  
-  // The state from the previous session (after restoring pinned tabs). This
-  // state is persisted and passed through to the next session during an app
-  // restart to make the third party add-on warning not trash the deferred
-  // session
-  _lastSessionState: null,
-
-  // When starting Firefox with a single private window, this is the place
-  // where we keep the session we actually wanted to restore in case the user
-  // decides to later open a non-private window as well.
-  _deferredInitialState: null,
-
-  // A promise resolved once initialization is complete
-  _promiseInitialization: Promise.defer(),
-
-  // Whether session has been initialized
-  _sessionInitialized: false,
-
-  // True if session store is disabled by multi-process browsing.
-  // See bug 516755.
-  _disabledForMultiProcess: false,
-
-  // The original "sessionstore.resume_session_once" preference value before it
-  // was modified by saveState.  saveState will set the
-  // "sessionstore.resume_session_once" to true when the
-  // the "sessionstore.resume_from_crash" preference is false (crash recovery
-  // is disabled) so that pinned tabs will be restored in the case of a
-  // crash.  This variable is used to restore the original value so the
-  // previous session is not always restored when
-  // "sessionstore.resume_from_crash" is true.
-  _resume_session_once_on_shutdown: null,
-
-  /**
-   * A promise fulfilled once initialization is complete.
-   */
-  get promiseInitialized() {
-    return this._promiseInitialization;
-  },
-
-  /* ........ Public Getters .............. */
-  get canRestoreLastSession() {
-    return this._lastSessionState;
-  },
-
-  set canRestoreLastSession(val) {
-    this._lastSessionState = null;
-  },
-
-  /* ........ Global Event Handlers .............. */
-
-  /**
-   * Initialize the component
-   */
-  initService: function ssi_initService() {
-    if (this._sessionInitialized) {
-      return;
-    }
-    OBSERVING.forEach(function(aTopic) {
-      Services.obs.addObserver(this, aTopic, true);
-    }, this);
-
-    this._initPrefs();
-
-    this._disabledForMultiProcess = false;
-
-    // this pref is only read at startup, so no need to observe it
-    this._sessionhistory_max_entries =
-      this._prefBranch.getIntPref("sessionhistory.max_entries");
-
-    gSessionStartup.onceInitialized.then(
-      this.initSession.bind(this)
-    );
-  },
-
-  initSession: function ssi_initSession() {
-    let ss = gSessionStartup;
-    try {
-      if (ss.doRestore() ||
-          ss.sessionType == Ci.nsISessionStartup.DEFER_SESSION)
-        this._initialState = ss.state;
-    }
-    catch(ex) { dump(ex + "\n"); } // no state to restore, which is ok
-
-    if (this._initialState) {
-      try {
-        // If we're doing a DEFERRED session, then we want to pull pinned tabs
-        // out so they can be restored.
-        if (ss.sessionType == Ci.nsISessionStartup.DEFER_SESSION) {
-          let [iniState, remainingState] = this._prepDataForDeferredRestore(this._initialState);
-          // If we have a iniState with windows, that means that we have windows
-          // with app tabs to restore.
-          if (iniState.windows.length)
-            this._initialState = iniState;
-          else
-            this._initialState = null;
-          if (remainingState.windows.length)
-            this._lastSessionState = remainingState;
-        }
-        else {
-          // Get the last deferred session in case the user still wants to
-          // restore it
-          this._lastSessionState = this._initialState.lastSessionState;
-
-          let lastSessionCrashed =
-            this._initialState.session && this._initialState.session.state &&
-            this._initialState.session.state == STATE_RUNNING_STR;
-          if (lastSessionCrashed) {
-            this._recentCrashes = (this._initialState.session &&
-                                   this._initialState.session.recentCrashes || 0) + 1;
-
-            if (this._needsRestorePage(this._initialState, this._recentCrashes)) {
-              // replace the crashed session with a restore-page-only session
-              let pageData = {
-                url: "about:sessionrestore",
-                formdata: {
-                  id: { "sessionData": this._initialState },
-                  xpath: {}
-                }
-              };
-              this._initialState = { windows: [{ tabs: [{ entries: [pageData] }] }] };
-            }
-          }
-
-          // Load the session start time from the previous state
-          this._sessionStartTime = this._initialState.session &&
-                                   this._initialState.session.startTime ||
-                                   this._sessionStartTime;
-
-          // make sure that at least the first window doesn't have anything hidden
-          delete this._initialState.windows[0].hidden;
-          // Since nothing is hidden in the first window, it cannot be a popup
-          delete this._initialState.windows[0].isPopup;
-          // We don't want to minimize and then open a window at startup.
-          if (this._initialState.windows[0].sizemode == "minimized")
-            this._initialState.windows[0].sizemode = "normal";
-          // clear any lastSessionWindowID attributes since those don't matter
-          // during normal restore
-          this._initialState.windows.forEach(function(aWindow) {
-            delete aWindow.__lastSessionWindowID;
-          });
-        }
-      }
-      catch (ex) { debug("The session file is invalid: " + ex); }
-    }
-
-    // A Lazy getter for the sessionstore.js backup promise.
-    XPCOMUtils.defineLazyGetter(this, "_backupSessionFileOnce", function () {
-      return _SessionFile.createBackupCopy();
-    });
-
-    // at this point, we've as good as resumed the session, so we can
-    // clear the resume_session_once flag, if it's set
-    if (this._loadState != STATE_QUITTING &&
-        this._prefBranch.getBoolPref("sessionstore.resume_session_once"))
-      this._prefBranch.setBoolPref("sessionstore.resume_session_once", false);
-
-    this._initEncoding();
-
-    // Session is ready.
-    this._sessionInitialized = true;
-    this._promiseInitialization.resolve();
-  },
-
-  _initEncoding : function ssi_initEncoding() {
-    // The (UTF-8) encoder used to write to files.
-    XPCOMUtils.defineLazyGetter(this, "_writeFileEncoder", function () {
-      return new TextEncoder();
-    });
-  },
-
-  _initPrefs : function() {
-    XPCOMUtils.defineLazyGetter(this, "_prefBranch", function () {
-      return Services.prefs.getBranch("browser.");
-    });
-
-    // minimal interval between two save operations (in milliseconds)
-    XPCOMUtils.defineLazyGetter(this, "_interval", function () {
-      // used often, so caching/observing instead of fetching on-demand
-      this._prefBranch.addObserver("sessionstore.interval", this, true);
-      return this._prefBranch.getIntPref("sessionstore.interval");
-    });
-
-    // when crash recovery is disabled, session data is not written to disk
-    XPCOMUtils.defineLazyGetter(this, "_resume_from_crash", function () {
-      // get crash recovery state from prefs and allow for proper reaction to state changes
-      this._prefBranch.addObserver("sessionstore.resume_from_crash", this, true);
-      return this._prefBranch.getBoolPref("sessionstore.resume_from_crash");
-    });
-
-    this._max_tabs_undo = this._prefBranch.getIntPref("sessionstore.max_tabs_undo");
-    this._prefBranch.addObserver("sessionstore.max_tabs_undo", this, true);
-    
-    this._max_windows_undo = this._prefBranch.getIntPref("sessionstore.max_windows_undo");
-    this._prefBranch.addObserver("sessionstore.max_windows_undo", this, true);
-    
-    // Straight-up collect the following one-time prefs
-    this._maxConcurrentTabRestores = 
-         Services.prefs.getIntPref("browser.sessionstore.max_concurrent_tabs");
-    // ensure a sane value for concurrency, ignore and set default otherwise
-    if (this._maxConcurrentTabRestores < 1 || this._maxConcurrentTabRestores > 10) {
-      this._maxConcurrentTabRestores = DEFAULT_MAX_CONCURRENT_TAB_RESTORES;
-    }
-    this._cacheBehavior =
-         Services.prefs.getIntPref("browser.sessionstore.cache_behavior");
-    
-  },
-
-  _initWindow: function ssi_initWindow(aWindow) {
-    if (aWindow) {
-      this.onLoad(aWindow);
-    } else if (this._loadState == STATE_STOPPED) {
-      // If init is being called with a null window, it's possible that we
-      // just want to tell sessionstore that a session is live (as is the case
-      // with starting Firefox with -private, for example; see bug 568816),
-      // so we should mark the load state as running to make sure that
-      // things like setBrowserState calls will succeed in restoring the session.
-      this._loadState = STATE_RUNNING;
-    }
-  },
-
-  /**
-   * Start tracking a window.
-   *
-   * This function also initializes the component if it is not
-   * initialized yet.
-   */
-  init: function ssi_init(aWindow) {
-    let self = this;
-    this.initService();
-    return this._promiseInitialization.promise.then(
-      function onSuccess() {
-        self._initWindow(aWindow);
-      }
-    );
-  },
-
-  /**
-   * Called on application shutdown, after notifications:
-   * quit-application-granted, quit-application
-   */
-  _uninit: function ssi_uninit() {
-    // save all data for session resuming
-    if (this._sessionInitialized)
-      this.saveState(true);
-
-    // clear out priority queue in case it's still holding refs
-    TabRestoreQueue.reset();
-
-    // Make sure to break our cycle with the save timer
-    if (this._saveTimer) {
-      this._saveTimer.cancel();
-      this._saveTimer = null;
-    }
-  },
-
-  /**
-   * Handle notifications
-   */
-  observe: function ssi_observe(aSubject, aTopic, aData) {
-    if (this._disabledForMultiProcess)
-      return;
-
-    switch (aTopic) {
-      case "domwindowopened": // catch new windows
-        this.onOpen(aSubject);
-        break;
-      case "domwindowclosed": // catch closed windows
-        this.onClose(aSubject);
-        break;
-      case "quit-application-requested":
-        this.onQuitApplicationRequested();
-        break;
-      case "quit-application-granted":
-        this.onQuitApplicationGranted();
-        break;
-      case "browser-lastwindow-close-granted":
-        this.onLastWindowCloseGranted();
-        break;
-      case "quit-application":
-        this.onQuitApplication(aData);
-        break;
-      case "browser:purge-session-history": // catch sanitization
-        this.onPurgeSessionHistory();
-        break;
-      case "browser:purge-domain-data":
-        this.onPurgeDomainData(aData);
-        break;
-      case "nsPref:changed": // catch pref changes
-        this.onPrefChange(aData);
-        break;
-      case "timer-callback": // timer call back for delayed saving
-        this.onTimerCallback();
-        break;
-    }
-  },
-
-  /**
-   * This method handles incoming messages sent by the session store content
-   * script and thus enables communication with OOP tabs.
-   */
-  receiveMessage: function ssi_receiveMessage(aMessage) {
-    var browser = aMessage.target;
-    var win = browser.ownerDocument.defaultView;
-
-    switch (aMessage.name) {
-      case "SessionStore:pageshow":
-        this.onTabLoad(win, browser);
-        break;
-      case "SessionStore:input":
-        this.onTabInput(win, browser);
-        break;
-      default:
-        debug("received unknown message '" + aMessage.name + "'");
-        break;
-    }
-
-    this._clearRestoringWindows();
-  },
-
-  /* ........ Window Event Handlers .............. */
-
-  /**
-   * Implement nsIDOMEventListener for handling various window and tab events
-   */
-  handleEvent: function ssi_handleEvent(aEvent) {
-    if (this._disabledForMultiProcess)
-      return;
-
-    var win = aEvent.currentTarget.ownerDocument.defaultView;
-    switch (aEvent.type) {
-      case "load":
-        // If __SS_restore_data is set, then we need to restore the document
-        // (form data, scrolling, etc.). This will only happen when a tab is
-        // first restored.
-        let browser = aEvent.currentTarget;
-        if (browser.__SS_restore_data)
-          this.restoreDocument(win, browser, aEvent);
-        this.onTabLoad(win, browser);
-        break;
-      case "TabOpen":
-        this.onTabAdd(win, aEvent.originalTarget);
-        break;
-      case "TabClose":
-        // aEvent.detail determines if the tab was closed by moving to a different window
-        if (!aEvent.detail)
-          this.onTabClose(win, aEvent.originalTarget);
-        this.onTabRemove(win, aEvent.originalTarget);
-        break;
-      case "TabSelect":
-        this.onTabSelect(win);
-        break;
-      case "TabShow":
-        this.onTabShow(win, aEvent.originalTarget);
-        break;
-      case "TabHide":
-        this.onTabHide(win, aEvent.originalTarget);
-        break;
-      case "TabPinned":
-      case "TabUnpinned":
-        this.saveStateDelayed(win);
-        break;
-    }
-
-    this._clearRestoringWindows();
-  },
-
-  /**
-   * If it's the first window load since app start...
-   * - determine if we're reloading after a crash or a forced-restart
-   * - restore window state
-   * - restart downloads
-   * Set up event listeners for this window's tabs
-   * @param aWindow
-   *        Window reference
-   */
-  onLoad: function ssi_onLoad(aWindow) {
-    // return if window has already been initialized
-    if (aWindow && aWindow.__SSi && this._windows[aWindow.__SSi])
-      return;
-
-    // ignore non-browser windows and windows opened while shutting down
-    if (aWindow.document.documentElement.getAttribute("windowtype") != "navigator:browser" ||
-        this._loadState == STATE_QUITTING)
-      return;
-
-    // assign it a unique identifier (timestamp)
-    aWindow.__SSi = "window" + Date.now();
-
-    // and create its data object
-    this._windows[aWindow.__SSi] = { tabs: [], selected: 0, _closedTabs: [], busy: false };
-
-    // and create its internal data object
-    this._internalWindows[aWindow.__SSi] = { hosts: {} }
-
-    let isPrivateWindow = false;
-    if (PrivateBrowsingUtils.isWindowPrivate(aWindow))
-      this._windows[aWindow.__SSi].isPrivate = isPrivateWindow = true;
-    if (!this._isWindowLoaded(aWindow))
-      this._windows[aWindow.__SSi]._restoring = true;
-    if (!aWindow.toolbar.visible)
-      this._windows[aWindow.__SSi].isPopup = true;
-
-    // perform additional initialization when the first window is loading
-    if (this._loadState == STATE_STOPPED) {
-      this._loadState = STATE_RUNNING;
-      this._lastSaveTime = Date.now();
-
-      // restore a crashed session resp. resume the last session if requested
-      if (this._initialState) {
-        if (isPrivateWindow) {
-          // We're starting with a single private window. Save the state we
-          // actually wanted to restore so that we can do it later in case
-          // the user opens another, non-private window.
-          this._deferredInitialState = gSessionStartup.state;
-          delete this._initialState;
-
-          // Nothing to restore now, notify observers things are complete.
-          Services.obs.notifyObservers(null, NOTIFY_WINDOWS_RESTORED, "");
-        } else {
-          // make sure that the restored tabs are first in the window
-          this._initialState._firstTabs = true;
-          this._restoreCount = this._initialState.windows ? this._initialState.windows.length : 0;
-          this.restoreWindow(aWindow, this._initialState,
-                             this._isCmdLineEmpty(aWindow, this._initialState));
-          delete this._initialState;
-
-          // _loadState changed from "stopped" to "running"
-          // force a save operation so that crashes happening during startup are correctly counted
-          this.saveState(true);
-        }
-      }
-      else {
-        // Nothing to restore, notify observers things are complete.
-        Services.obs.notifyObservers(null, NOTIFY_WINDOWS_RESTORED, "");
-
-        // the next delayed save request should execute immediately
-        this._lastSaveTime -= this._interval;
-      }
-    }
-    // this window was opened by _openWindowWithState
-    else if (!this._isWindowLoaded(aWindow)) {
-      let followUp = this._statesToRestore[aWindow.__SS_restoreID].windows.length == 1;
-      this.restoreWindow(aWindow, this._statesToRestore[aWindow.__SS_restoreID], true, followUp);
-    }
-    // The user opened another, non-private window after starting up with
-    // a single private one. Let's restore the session we actually wanted to
-    // restore at startup.
-    else if (this._deferredInitialState && !isPrivateWindow &&
-             aWindow.toolbar.visible) {
-
-      this._deferredInitialState._firstTabs = true;
-      this._restoreCount = this._deferredInitialState.windows ?
-        this._deferredInitialState.windows.length : 0;
-      this.restoreWindow(aWindow, this._deferredInitialState, false);
-      this._deferredInitialState = null;
-    }
-    else if (this._restoreLastWindow && aWindow.toolbar.visible &&
-             this._closedWindows.length && !isPrivateWindow) {
-
-      // default to the most-recently closed window
-      // don't use popup windows
-      let closedWindowState = null;
-      let closedWindowIndex;
-      for (let i = 0; i < this._closedWindows.length; i++) {
-        // Take the first non-popup, point our object at it, and break out.
-        if (!this._closedWindows[i].isPopup) {
-          closedWindowState = this._closedWindows[i];
-          closedWindowIndex = i;
-          break;
-        }
-      }
-
-      if (closedWindowState) {
-        let newWindowState;
-#ifndef XP_MACOSX
-        if (!this._doResumeSession()) {
-#endif
-          // We want to split the window up into pinned tabs and unpinned tabs.
-          // Pinned tabs should be restored. If there are any remaining tabs,
-          // they should be added back to _closedWindows.
-          // We'll cheat a little bit and reuse _prepDataForDeferredRestore
-          // even though it wasn't built exactly for this.
-          let [appTabsState, normalTabsState] =
-            this._prepDataForDeferredRestore({ windows: [closedWindowState] });
-
-          // These are our pinned tabs, which we should restore
-          if (appTabsState.windows.length) {
-            newWindowState = appTabsState.windows[0];
-            delete newWindowState.__lastSessionWindowID;
-          }
-
-          // In case there were no unpinned tabs, remove the window from _closedWindows
-          if (!normalTabsState.windows.length) {
-            this._closedWindows.splice(closedWindowIndex, 1);
-          }
-          // Or update _closedWindows with the modified state
-          else {
-            delete normalTabsState.windows[0].__lastSessionWindowID;
-            this._closedWindows[closedWindowIndex] = normalTabsState.windows[0];
-          }
-#ifndef XP_MACOSX
-        }
-        else {
-          // If we're just restoring the window, make sure it gets removed from
-          // _closedWindows.
-          this._closedWindows.splice(closedWindowIndex, 1);
-          newWindowState = closedWindowState;
-          delete newWindowState.hidden;
-        }
-#endif
-        if (newWindowState) {
-          // Ensure that the window state isn't hidden
-          this._restoreCount = 1;
-          let state = { windows: [newWindowState] };
-          this.restoreWindow(aWindow, state, this._isCmdLineEmpty(aWindow, state));
-        }
-      }
-      // we actually restored the session just now.
-      this._prefBranch.setBoolPref("sessionstore.resume_session_once", false);
-    }
-    if (this._restoreLastWindow && aWindow.toolbar.visible) {
-      // always reset (if not a popup window)
-      // we don't want to restore a window directly after, for example,
-      // undoCloseWindow was executed.
-      this._restoreLastWindow = false;
-    }
-
-    var tabbrowser = aWindow.gBrowser;
-
-    // add tab change listeners to all already existing tabs
-    for (let i = 0; i < tabbrowser.tabs.length; i++) {
-      this.onTabAdd(aWindow, tabbrowser.tabs[i], true);
-    }
-    // notification of tab add/remove/selection/show/hide
-    TAB_EVENTS.forEach(function(aEvent) {
-      tabbrowser.tabContainer.addEventListener(aEvent, this, true);
-    }, this);
-  },
-
-  /**
-   * On window open
-   * @param aWindow
-   *        Window reference
-   */
-  onOpen: function ssi_onOpen(aWindow) {
-    var _this = this;
-    aWindow.addEventListener("load", function(aEvent) {
-      aEvent.currentTarget.removeEventListener("load", arguments.callee, false);
-      _this.onLoad(aEvent.currentTarget);
-    }, false);
-    return;
-  },
-
-  /**
-   * On window close...
-   * - remove event listeners from tabs
-   * - save all window data
-   * @param aWindow
-   *        Window reference
-   */
-  onClose: function ssi_onClose(aWindow) {
-    // this window was about to be restored - conserve its original data, if any
-    let isFullyLoaded = this._isWindowLoaded(aWindow);
-    if (!isFullyLoaded) {
-      if (!aWindow.__SSi)
-        aWindow.__SSi = "window" + Date.now();
-      this._windows[aWindow.__SSi] = this._statesToRestore[aWindow.__SS_restoreID];
-      delete this._statesToRestore[aWindow.__SS_restoreID];
-      delete aWindow.__SS_restoreID;
-    }
-
-    // ignore windows not tracked by SessionStore
-    if (!aWindow.__SSi || !this._windows[aWindow.__SSi]) {
-      return;
-    }
-
-    // notify that the session store will stop tracking this window so that
-    // extensions can store any data about this window in session store before
-    // that's not possible anymore
-    let event = aWindow.document.createEvent("Events");
-    event.initEvent("SSWindowClosing", true, false);
-    aWindow.dispatchEvent(event);
-
-    if (this.windowToFocus && this.windowToFocus == aWindow) {
-      delete this.windowToFocus;
-    }
-
-    var tabbrowser = aWindow.gBrowser;
-
-    TAB_EVENTS.forEach(function(aEvent) {
-      tabbrowser.tabContainer.removeEventListener(aEvent, this, true);
-    }, this);
-
-    // remove the progress listener for this window
-    tabbrowser.removeTabsProgressListener(gRestoreTabsProgressListener);
-
-    let winData = this._windows[aWindow.__SSi];
-    if (this._loadState == STATE_RUNNING) { // window not closed during a regular shut-down
-      // update all window data for a last time
-      this._collectWindowData(aWindow);
-
-      if (isFullyLoaded) {
-        winData.title = aWindow.content.document.title || tabbrowser.selectedTab.label;
-        winData.title = this._replaceLoadingTitle(winData.title, tabbrowser,
-                                                  tabbrowser.selectedTab);
-        let windows = {};
-        windows[aWindow.__SSi] = winData;
-        this._updateCookies(windows);
-      }
-
-#ifndef XP_MACOSX
-      // Until we decide otherwise elsewhere, this window is part of a series
-      // of closing windows to quit.
-      winData._shouldRestore = true;
-#endif
-
-      // Save the window if it has multiple tabs or a single saveable tab and
-      // it's not private.
-      if (!winData.isPrivate && (winData.tabs.length > 1 ||
-          (winData.tabs.length == 1 && this._shouldSaveTabState(winData.tabs[0])))) {
-        // we don't want to save the busy state
-        delete winData.busy;
-
-        this._closedWindows.unshift(winData);
-        this._capClosedWindows();
-      }
-
-      // clear this window from the list
-      delete this._windows[aWindow.__SSi];
-      delete this._internalWindows[aWindow.__SSi];
-
-      // save the state without this window to disk
-      this.saveStateDelayed();
-    }
-
-    for (let i = 0; i < tabbrowser.tabs.length; i++) {
-      this.onTabRemove(aWindow, tabbrowser.tabs[i], true);
-    }
-
-    // Cache the window state until it is completely gone.
-    DyingWindowCache.set(aWindow, winData);
-
-    delete aWindow.__SSi;
-  },
-
-  /**
-   * On quit application requested
-   */
-  onQuitApplicationRequested: function ssi_onQuitApplicationRequested() {
-    // get a current snapshot of all windows
-    this._forEachBrowserWindow(function(aWindow) {
-      this._collectWindowData(aWindow);
-    });
-    // we must cache this because _getMostRecentBrowserWindow will always
-    // return null by the time quit-application occurs
-    var activeWindow = this._getMostRecentBrowserWindow();
-    if (activeWindow)
-      this.activeWindowSSiCache = activeWindow.__SSi || "";
-    this._dirtyWindows = [];
-  },
-
-  /**
-   * On quit application granted
-   */
-  onQuitApplicationGranted: function ssi_onQuitApplicationGranted() {
-    // freeze the data at what we've got (ignoring closing windows)
-    this._loadState = STATE_QUITTING;
-  },
-
-  /**
-   * On last browser window close
-   */
-  onLastWindowCloseGranted: function ssi_onLastWindowCloseGranted() {
-    // last browser window is quitting.
-    // remember to restore the last window when another browser window is opened
-    // do not account for pref(resume_session_once) at this point, as it might be
-    // set by another observer getting this notice after us
-    this._restoreLastWindow = true;
-  },
-
-  /**
-   * On quitting application
-   * @param aData
-   *        String type of quitting
-   */
-  onQuitApplication: function ssi_onQuitApplication(aData) {
-    if (aData == "restart") {
-      this._prefBranch.setBoolPref("sessionstore.resume_session_once", true);
-      // The browser:purge-session-history notification fires after the
-      // quit-application notification so unregister the
-      // browser:purge-session-history notification to prevent clearing
-      // session data on disk on a restart.  It is also unnecessary to
-      // perform any other sanitization processing on a restart as the
-      // browser is about to exit anyway.
-      Services.obs.removeObserver(this, "browser:purge-session-history");
-    }
-    else if (this._resume_session_once_on_shutdown != null) {
-      // if the sessionstore.resume_session_once preference was changed by
-      // saveState because crash recovery is disabled then restore the
-      // preference back to the value it was prior to that.  This will prevent
-      // SessionStore from always restoring the session when crash recovery is
-      // disabled.
-      this._prefBranch.setBoolPref("sessionstore.resume_session_once",
-                                   this._resume_session_once_on_shutdown);
-    }
-
-    if (aData != "restart") {
-      // Throw away the previous session on shutdown
-      this._lastSessionState = null;
-    }
-
-    this._loadState = STATE_QUITTING; // just to be sure
-    this._uninit();
-  },
-
-  /**
-   * On purge of session history
-   */
-  onPurgeSessionHistory: function ssi_onPurgeSessionHistory() {
-    var _this = this;
-    _SessionFile.wipe();
-    // If the browser is shutting down, simply return after clearing the
-    // session data on disk as this notification fires after the
-    // quit-application notification so the browser is about to exit.
-    if (this._loadState == STATE_QUITTING)
-      return;
-    this._lastSessionState = null;
-    let openWindows = {};
-    this._forEachBrowserWindow(function(aWindow) {
-      Array.forEach(aWindow.gBrowser.tabs, function(aTab) {
-        delete aTab.linkedBrowser.__SS_data;
-        delete aTab.linkedBrowser.__SS_tabStillLoading;
-        delete aTab.linkedBrowser.__SS_formDataSaved;
-        delete aTab.linkedBrowser.__SS_hostSchemeData;
-        if (aTab.linkedBrowser.__SS_restoreState)
-          this._resetTabRestoringState(aTab);
-      }, this);
-      openWindows[aWindow.__SSi] = true;
-    });
-    // also clear all data about closed tabs and windows
-    for (let ix in this._windows) {
-      if (ix in openWindows) {
-        this._windows[ix]._closedTabs = [];
-      }
-      else {
-        delete this._windows[ix];
-        delete this._internalWindows[ix];
-      }
-    }
-    // also clear all data about closed windows
-    this._closedWindows = [];
-    // give the tabbrowsers a chance to clear their histories first
-    var win = this._getMostRecentBrowserWindow();
-    if (win)
-      win.setTimeout(function() { _this.saveState(true); }, 0);
-    else if (this._loadState == STATE_RUNNING)
-      this.saveState(true);
-    // Delete the private browsing backed up state, if any
-    if ("_stateBackup" in this)
-      delete this._stateBackup;
-
-    this._clearRestoringWindows();
-  },
-
-  /**
-   * On purge of domain data
-   * @param aData
-   *        String domain data
-   */
-  onPurgeDomainData: function ssi_onPurgeDomainData(aData) {
-    // does a session history entry contain a url for the given domain?
-    function containsDomain(aEntry) {
-      try {
-        if (this._getURIFromString(aEntry.url).host.hasRootDomain(aData))
-          return true;
-      }
-      catch (ex) { /* url had no host at all */ }
-      return aEntry.children && aEntry.children.some(containsDomain, this);
-    }
-    // remove all closed tabs containing a reference to the given domain
-    for (let ix in this._windows) {
-      let closedTabs = this._windows[ix]._closedTabs;
-      for (let i = closedTabs.length - 1; i >= 0; i--) {
-        if (closedTabs[i].state.entries.some(containsDomain, this))
-          closedTabs.splice(i, 1);
-      }
-    }
-    // remove all open & closed tabs containing a reference to the given
-    // domain in closed windows
-    for (let ix = this._closedWindows.length - 1; ix >= 0; ix--) {
-      let closedTabs = this._closedWindows[ix]._closedTabs;
-      let openTabs = this._closedWindows[ix].tabs;
-      let openTabCount = openTabs.length;
-      for (let i = closedTabs.length - 1; i >= 0; i--)
-        if (closedTabs[i].state.entries.some(containsDomain, this))
-          closedTabs.splice(i, 1);
-      for (let j = openTabs.length - 1; j >= 0; j--) {
-        if (openTabs[j].entries.some(containsDomain, this)) {
-          openTabs.splice(j, 1);
-          if (this._closedWindows[ix].selected > j)
-            this._closedWindows[ix].selected--;
-        }
-      }
-      if (openTabs.length == 0) {
-        this._closedWindows.splice(ix, 1);
-      }
-      else if (openTabs.length != openTabCount) {
-        // Adjust the window's title if we removed an open tab
-        let selectedTab = openTabs[this._closedWindows[ix].selected - 1];
-        // some duplication from restoreHistory - make sure we get the correct title
-        let activeIndex = (selectedTab.index || selectedTab.entries.length) - 1;
-        if (activeIndex >= selectedTab.entries.length)
-          activeIndex = selectedTab.entries.length - 1;
-        this._closedWindows[ix].title = selectedTab.entries[activeIndex].title;
-      }
-    }
-    if (this._loadState == STATE_RUNNING)
-      this.saveState(true);
-
-    this._clearRestoringWindows();
-  },
-
-  /**
-   * On preference change
-   * @param aData
-   *        String preference changed
-   */
-  onPrefChange: function ssi_onPrefChange(aData) {
-    switch (aData) {
-      // if the user decreases the max number of closed tabs they want
-      // preserved update our internal states to match that max
-      case "sessionstore.max_tabs_undo":
-        this._max_tabs_undo = this._prefBranch.getIntPref("sessionstore.max_tabs_undo");
-        for (let ix in this._windows) {
-          this._windows[ix]._closedTabs.splice(this._max_tabs_undo, this._windows[ix]._closedTabs.length);
-        }
-        break;
-      case "sessionstore.max_windows_undo":
-        this._max_windows_undo = this._prefBranch.getIntPref("sessionstore.max_windows_undo");
-        this._capClosedWindows();
-        break;
-      case "sessionstore.interval":
-        this._interval = this._prefBranch.getIntPref("sessionstore.interval");
-        // reset timer and save
-        if (this._saveTimer) {
-          this._saveTimer.cancel();
-          this._saveTimer = null;
-        }
-        this.saveStateDelayed(null, -1);
-        break;
-      case "sessionstore.resume_from_crash":
-        this._resume_from_crash = this._prefBranch.getBoolPref("sessionstore.resume_from_crash");
-        // restore original resume_session_once preference if set in saveState
-        if (this._resume_session_once_on_shutdown != null) {
-          this._prefBranch.setBoolPref("sessionstore.resume_session_once",
-                                       this._resume_session_once_on_shutdown);
-          this._resume_session_once_on_shutdown = null;
-        }
-        // either create the file with crash recovery information or remove it
-        // (when _loadState is not STATE_RUNNING, that file is used for session resuming instead)
-        if (!this._resume_from_crash)
-          _SessionFile.wipe();
-        this.saveState(true);
-        break;
-    }
-  },
-
-  /**
-   * On timer callback
-   */
-  onTimerCallback: function ssi_onTimerCallback() {
-    this._saveTimer = null;
-    this.saveState();
-  },
-
-  /**
-   * set up listeners for a new tab
-   * @param aWindow
-   *        Window reference
-   * @param aTab
-   *        Tab reference
-   * @param aNoNotification
-   *        bool Do not save state if we're updating an existing tab
-   */
-  onTabAdd: function ssi_onTabAdd(aWindow, aTab, aNoNotification) {
-    let browser = aTab.linkedBrowser;
-    browser.addEventListener("load", this, true);
-
-    let mm = browser.messageManager;
-    MESSAGES.forEach(msg => mm.addMessageListener(msg, this));
-
-    if (!aNoNotification) {
-      this.saveStateDelayed(aWindow);
-    }
-  },
-
-  /**
-   * remove listeners for a tab
-   * @param aWindow
-   *        Window reference
-   * @param aTab
-   *        Tab reference
-   * @param aNoNotification
-   *        bool Do not save state if we're updating an existing tab
-   */
-  onTabRemove: function ssi_onTabRemove(aWindow, aTab, aNoNotification) {
-    let browser = aTab.linkedBrowser;
-    browser.removeEventListener("load", this, true);
-
-    let mm = browser.messageManager;
-    MESSAGES.forEach(msg => mm.removeMessageListener(msg, this));
-
-    delete browser.__SS_data;
-    delete browser.__SS_tabStillLoading;
-    delete browser.__SS_formDataSaved;
-    delete browser.__SS_hostSchemeData;
-
-    // If this tab was in the middle of restoring or still needs to be restored,
-    // we need to reset that state. If the tab was restoring, we will attempt to
-    // restore the next tab.
-    let previousState = browser.__SS_restoreState;
-    if (previousState) {
-      this._resetTabRestoringState(aTab);
-      if (previousState == TAB_STATE_RESTORING)
-        this.restoreNextTab();
-    }
-
-    if (!aNoNotification) {
-      this.saveStateDelayed(aWindow);
-    }
-  },
-
-  /**
-   * When a tab closes, collect its properties
-   * @param aWindow
-   *        Window reference
-   * @param aTab
-   *        Tab reference
-   */
-  onTabClose: function ssi_onTabClose(aWindow, aTab) {
-    // notify the tabbrowser that the tab state will be retrieved for the last time
-    // (so that extension authors can easily set data on soon-to-be-closed tabs)
-    var event = aWindow.document.createEvent("Events");
-    event.initEvent("SSTabClosing", true, false);
-    aTab.dispatchEvent(event);
-
-    // don't update our internal state if we don't have to
-    if (this._max_tabs_undo == 0) {
-      return;
-    }
-
-    // make sure that the tab related data is up-to-date
-    var tabState = this._collectTabData(aTab);
-    this._updateTextAndScrollDataForTab(aWindow, aTab.linkedBrowser, tabState);
-
-    // store closed-tab data for undo
-    if (this._shouldSaveTabState(tabState)) {
-      let tabTitle = aTab.label;
-      let tabbrowser = aWindow.gBrowser;
-      tabTitle = this._replaceLoadingTitle(tabTitle, tabbrowser, aTab);
-
-      this._windows[aWindow.__SSi]._closedTabs.unshift({
-        state: tabState,
-        title: tabTitle,
-        image: tabbrowser.getIcon(aTab),
-        pos: aTab._tPos
-      });
-      var length = this._windows[aWindow.__SSi]._closedTabs.length;
-      if (length > this._max_tabs_undo)
-        this._windows[aWindow.__SSi]._closedTabs.splice(this._max_tabs_undo, length - this._max_tabs_undo);
-    }
-  },
-
-  /**
-   * When a tab loads, save state.
-   * @param aWindow
-   *        Window reference
-   * @param aBrowser
-   *        Browser reference
-   */
-  onTabLoad: function ssi_onTabLoad(aWindow, aBrowser) {
-    // react on "load" and solitary "pageshow" events (the first "pageshow"
-    // following "load" is too late for deleting the data caches)
-    // It's possible to get a load event after calling stop on a browser (when
-    // overwriting tabs). We want to return early if the tab hasn't been restored yet.
-    if (aBrowser.__SS_restoreState &&
-        aBrowser.__SS_restoreState == TAB_STATE_NEEDS_RESTORE) {
-      return;
-    }
-
-    delete aBrowser.__SS_data;
-    delete aBrowser.__SS_tabStillLoading;
-    delete aBrowser.__SS_formDataSaved;
-    this.saveStateDelayed(aWindow);
-
-  },
-
-  /**
-   * Called when a browser sends the "input" notification
-   * @param aWindow
-   *        Window reference
-   * @param aBrowser
-   *        Browser reference
-   */
-  onTabInput: function ssi_onTabInput(aWindow, aBrowser) {
-    // deleting __SS_formDataSaved will cause us to recollect form data
-    delete aBrowser.__SS_formDataSaved;
-
-    this.saveStateDelayed(aWindow, 3000);
-  },
-
-  /**
-   * When a tab is selected, save session data
-   * @param aWindow
-   *        Window reference
-   */
-  onTabSelect: function ssi_onTabSelect(aWindow) {
-    if (this._loadState == STATE_RUNNING) {
-      this._windows[aWindow.__SSi].selected = aWindow.gBrowser.tabContainer.selectedIndex;
-
-      let tab = aWindow.gBrowser.selectedTab;
-      // If __SS_restoreState is still on the browser and it is
-      // TAB_STATE_NEEDS_RESTORE, then then we haven't restored
-      // this tab yet. Explicitly call restoreTab to kick off the restore.
-      if (tab.linkedBrowser.__SS_restoreState &&
-          tab.linkedBrowser.__SS_restoreState == TAB_STATE_NEEDS_RESTORE)
-        this.restoreTab(tab);
-
-    }
-  },
-
-  onTabShow: function ssi_onTabShow(aWindow, aTab) {
-    // If the tab hasn't been restored yet, move it into the right bucket
-    if (aTab.linkedBrowser.__SS_restoreState &&
-        aTab.linkedBrowser.__SS_restoreState == TAB_STATE_NEEDS_RESTORE) {
-      TabRestoreQueue.hiddenToVisible(aTab);
-
-      // let's kick off tab restoration again to ensure this tab gets restored
-      // with "restore_hidden_tabs" == false (now that it has become visible)
-      this.restoreNextTab();
-    }
-
-    // Default delay of 2 seconds gives enough time to catch multiple TabShow
-    // events due to changing groups in Panorama.
-    this.saveStateDelayed(aWindow);
-  },
-
-  onTabHide: function ssi_onTabHide(aWindow, aTab) {
-    // If the tab hasn't been restored yet, move it into the right bucket
-    if (aTab.linkedBrowser.__SS_restoreState &&
-        aTab.linkedBrowser.__SS_restoreState == TAB_STATE_NEEDS_RESTORE) {
-      TabRestoreQueue.visibleToHidden(aTab);
-    }
-
-    // Default delay of 2 seconds gives enough time to catch multiple TabHide
-    // events due to changing groups in Panorama.
-    this.saveStateDelayed(aWindow);
-  },
-
-  /* ........ nsISessionStore API .............. */
-
-  getBrowserState: function ssi_getBrowserState() {
-    return this._toJSONString(this._getCurrentState());
-  },
-
-  setBrowserState: function ssi_setBrowserState(aState) {
-    this._handleClosedWindows();
-
-    try {
-      var state = JSON.parse(aState);
-    }
-    catch (ex) { /* invalid state object - don't restore anything */ }
-    if (!state || !state.windows)
-      throw (Components.returnCode = Cr.NS_ERROR_INVALID_ARG);
-
-    this._browserSetState = true;
-
-    // Make sure the priority queue is emptied out
-    this._resetRestoringState();
-
-    var window = this._getMostRecentBrowserWindow();
-    if (!window) {
-      this._restoreCount = 1;
-      this._openWindowWithState(state);
-      return;
-    }
-
-    // close all other browser windows
-    this._forEachBrowserWindow(function(aWindow) {
-      if (aWindow != window) {
-        aWindow.close();
-        this.onClose(aWindow);
-      }
-    });
-
-    // make sure closed window data isn't kept
-    this._closedWindows = [];
-
-    // determine how many windows are meant to be restored
-    this._restoreCount = state.windows ? state.windows.length : 0;
-
-    // restore to the given state
-    this.restoreWindow(window, state, true);
-  },
-
-  getWindowState: function ssi_getWindowState(aWindow) {
-    if ("__SSi" in aWindow) {
-      return this._toJSONString(this._getWindowState(aWindow));
-    }
-
-    if (DyingWindowCache.has(aWindow)) {
-      let data = DyingWindowCache.get(aWindow);
-      return this._toJSONString({ windows: [data] });
-    }
-
-    throw (Components.returnCode = Cr.NS_ERROR_INVALID_ARG);
-  },
-
-  setWindowState: function ssi_setWindowState(aWindow, aState, aOverwrite) {
-    if (!aWindow.__SSi)
-      throw (Components.returnCode = Cr.NS_ERROR_INVALID_ARG);
-
-    this.restoreWindow(aWindow, aState, aOverwrite);
-  },
-
-  getTabState: function ssi_getTabState(aTab) {
-    if (!aTab.ownerDocument || !aTab.ownerDocument.defaultView.__SSi)
-      throw (Components.returnCode = Cr.NS_ERROR_INVALID_ARG);
-
-    var tabState = this._collectTabData(aTab);
-
-    var window = aTab.ownerDocument.defaultView;
-    this._updateTextAndScrollDataForTab(window, aTab.linkedBrowser, tabState);
-
-    return this._toJSONString(tabState);
-  },
-
-  setTabState: function ssi_setTabState(aTab, aState) {
-    var tabState = JSON.parse(aState);
-    if (!tabState.entries || !aTab.ownerDocument || !aTab.ownerDocument.defaultView.__SSi)
-      throw (Components.returnCode = Cr.NS_ERROR_INVALID_ARG);
-
-    var window = aTab.ownerDocument.defaultView;
-    this._setWindowStateBusy(window);
-    this.restoreHistoryPrecursor(window, [aTab], [tabState], 0, 0, 0);
-  },
-
-  duplicateTab: function ssi_duplicateTab(aWindow, aTab, aDelta) {
-    if (!aTab.ownerDocument || !aTab.ownerDocument.defaultView.__SSi ||
-        !aWindow.getBrowser)
-      throw (Components.returnCode = Cr.NS_ERROR_INVALID_ARG);
-
-    var tabState = this._collectTabData(aTab, true);
-    var sourceWindow = aTab.ownerDocument.defaultView;
-    this._updateTextAndScrollDataForTab(sourceWindow, aTab.linkedBrowser, tabState, true);
-    tabState.index += aDelta;
-    tabState.index = Math.max(1, Math.min(tabState.index, tabState.entries.length));
-    tabState.pinned = false;
-
-    this._setWindowStateBusy(aWindow);
-    let newTab = aTab == aWindow.gBrowser.selectedTab ?
-      aWindow.gBrowser.addTab(null, {relatedToCurrent: true, ownerTab: aTab}) :
-      aWindow.gBrowser.addTab();
-
-    this.restoreHistoryPrecursor(aWindow, [newTab], [tabState], 0, 0, 0,
-                                 true /* Load this tab right away. */);
-
-    return newTab;
-  },
-
-  getClosedTabCount: function ssi_getClosedTabCount(aWindow) {
-    if ("__SSi" in aWindow) {
-      return this._windows[aWindow.__SSi]._closedTabs.length;
-    }
-
-    if (DyingWindowCache.has(aWindow)) {
-      return DyingWindowCache.get(aWindow)._closedTabs.length;
-    }
-
-    throw (Components.returnCode = Cr.NS_ERROR_INVALID_ARG);
-  },
-
-  getClosedTabData: function ssi_getClosedTabDataAt(aWindow) {
-    if ("__SSi" in aWindow) {
-      return this._toJSONString(this._windows[aWindow.__SSi]._closedTabs);
-    }
-
-    if (DyingWindowCache.has(aWindow)) {
-      let data = DyingWindowCache.get(aWindow);
-      return this._toJSONString(data._closedTabs);
-    }
-
-    throw (Components.returnCode = Cr.NS_ERROR_INVALID_ARG);
-  },
-
-  undoCloseTab: function ssi_undoCloseTab(aWindow, aIndex) {
-    if (!aWindow.__SSi)
-      throw (Components.returnCode = Cr.NS_ERROR_INVALID_ARG);
-
-    var closedTabs = this._windows[aWindow.__SSi]._closedTabs;
-
-    // default to the most-recently closed tab
-    aIndex = aIndex || 0;
-    if (!(aIndex in closedTabs))
-      throw (Components.returnCode = Cr.NS_ERROR_INVALID_ARG);
-
-    // fetch the data of closed tab, while removing it from the array
-    let closedTab = closedTabs.splice(aIndex, 1).shift();
-    let closedTabState = closedTab.state;
-
-    this._setWindowStateBusy(aWindow);
-    // create a new tab
-    let tabbrowser = aWindow.gBrowser;
-    let tab = tabbrowser.addTab();
-
-    // restore tab content
-    this.restoreHistoryPrecursor(aWindow, [tab], [closedTabState], 1, 0, 0);
-
-    // restore the tab's position
-    tabbrowser.moveTabTo(tab, closedTab.pos);
-
-    // focus the tab's content area (bug 342432)
-    tab.linkedBrowser.focus();
-
-    return tab;
-  },
-
-  forgetClosedTab: function ssi_forgetClosedTab(aWindow, aIndex) {
-    if (!aWindow.__SSi)
-      throw (Components.returnCode = Cr.NS_ERROR_INVALID_ARG);
-
-    var closedTabs = this._windows[aWindow.__SSi]._closedTabs;
-
-    // default to the most-recently closed tab
-    aIndex = aIndex || 0;
-    if (!(aIndex in closedTabs))
-      throw (Components.returnCode = Cr.NS_ERROR_INVALID_ARG);
-
-    // remove closed tab from the array
-    closedTabs.splice(aIndex, 1);
-  },
-
-  getClosedWindowCount: function ssi_getClosedWindowCount() {
-    return this._closedWindows.length;
-  },
-
-  getClosedWindowData: function ssi_getClosedWindowData() {
-    return this._toJSONString(this._closedWindows);
-  },
-
-  undoCloseWindow: function ssi_undoCloseWindow(aIndex) {
-    if (!(aIndex in this._closedWindows))
-      throw (Components.returnCode = Cr.NS_ERROR_INVALID_ARG);
-
-    // reopen the window
-    let state = { windows: this._closedWindows.splice(aIndex, 1) };
-    let window = this._openWindowWithState(state);
-    this.windowToFocus = window;
-    return window;
-  },
-
-  forgetClosedWindow: function ssi_forgetClosedWindow(aIndex) {
-    // default to the most-recently closed window
-    aIndex = aIndex || 0;
-    if (!(aIndex in this._closedWindows))
-      throw (Components.returnCode = Cr.NS_ERROR_INVALID_ARG);
-
-    // remove closed window from the array
-    this._closedWindows.splice(aIndex, 1);
-  },
-
-  getWindowValue: function ssi_getWindowValue(aWindow, aKey) {
-    if ("__SSi" in aWindow) {
-      var data = this._windows[aWindow.__SSi].extData || {};
-      return data[aKey] || "";
-    }
-
-    if (DyingWindowCache.has(aWindow)) {
-      let data = DyingWindowCache.get(aWindow).extData || {};
-      return data[aKey] || "";
-    }
-
-    throw (Components.returnCode = Cr.NS_ERROR_INVALID_ARG);
-  },
-
-  setWindowValue: function ssi_setWindowValue(aWindow, aKey, aStringValue) {
-    if (aWindow.__SSi) {
-      if (!this._windows[aWindow.__SSi].extData) {
-        this._windows[aWindow.__SSi].extData = {};
-      }
-      this._windows[aWindow.__SSi].extData[aKey] = aStringValue;
-      this.saveStateDelayed(aWindow);
-    }
-    else {
-      throw (Components.returnCode = Cr.NS_ERROR_INVALID_ARG);
-    }
-  },
-
-  deleteWindowValue: function ssi_deleteWindowValue(aWindow, aKey) {
-    if (aWindow.__SSi && this._windows[aWindow.__SSi].extData &&
-        this._windows[aWindow.__SSi].extData[aKey])
-      delete this._windows[aWindow.__SSi].extData[aKey];
-  },
-
-  getTabValue: function ssi_getTabValue(aTab, aKey) {
-    let data = {};
-    if (aTab.__SS_extdata) {
-      data = aTab.__SS_extdata;
-    }
-    else if (aTab.linkedBrowser.__SS_data && aTab.linkedBrowser.__SS_data.extData) {
-      // If the tab hasn't been fully restored, get the data from the to-be-restored data
-      data = aTab.linkedBrowser.__SS_data.extData;
-    }
-    return data[aKey] || "";
-  },
-
-  setTabValue: function ssi_setTabValue(aTab, aKey, aStringValue) {
-    // If the tab hasn't been restored, then set the data there, otherwise we
-    // could lose newly added data.
-    let saveTo;
-    if (aTab.__SS_extdata) {
-      saveTo = aTab.__SS_extdata;
-    }
-    else if (aTab.linkedBrowser.__SS_data && aTab.linkedBrowser.__SS_data.extData) {
-      saveTo = aTab.linkedBrowser.__SS_data.extData;
-    }
-    else {
-      aTab.__SS_extdata = {};
-      saveTo = aTab.__SS_extdata;
-    }
-    saveTo[aKey] = aStringValue;
-    this.saveStateDelayed(aTab.ownerDocument.defaultView);
-  },
-
-  deleteTabValue: function ssi_deleteTabValue(aTab, aKey) {
-    // We want to make sure that if data is accessed early, we attempt to delete
-    // that data from __SS_data as well. Otherwise we'll throw in cases where
-    // data can be set or read.
-    let deleteFrom;
-    if (aTab.__SS_extdata) {
-      deleteFrom = aTab.__SS_extdata;
-    }
-    else if (aTab.linkedBrowser.__SS_data && aTab.linkedBrowser.__SS_data.extData) {
-      deleteFrom = aTab.linkedBrowser.__SS_data.extData;
-    }
-
-    if (deleteFrom && deleteFrom[aKey])
-      delete deleteFrom[aKey];
-  },
-
-  persistTabAttribute: function ssi_persistTabAttribute(aName) {
-    if (TabAttributes.persist(aName)) {
-      this.saveStateDelayed();
-    }
-  },
-
-  /**
-   * Restores the session state stored in _lastSessionState. This will attempt
-   * to merge data into the current session. If a window was opened at startup
-   * with pinned tab(s), then the remaining data from the previous session for
-   * that window will be opened into that winddow. Otherwise new windows will
-   * be opened.
-   */
-  restoreLastSession: function ssi_restoreLastSession() {
-    // Use the public getter since it also checks PB mode
-    if (!this.canRestoreLastSession)
-      throw (Components.returnCode = Cr.NS_ERROR_FAILURE);
-
-    // First collect each window with its id...
-    let windows = {};
-    this._forEachBrowserWindow(function(aWindow) {
-      if (aWindow.__SS_lastSessionWindowID)
-        windows[aWindow.__SS_lastSessionWindowID] = aWindow;
-    });
-
-    let lastSessionState = this._lastSessionState;
-
-    // This shouldn't ever be the case...
-    if (!lastSessionState.windows.length)
-      throw (Components.returnCode = Cr.NS_ERROR_UNEXPECTED);
-
-    // We're technically doing a restore, so set things up so we send the
-    // notification when we're done. We want to send "sessionstore-browser-state-restored".
-    this._restoreCount = lastSessionState.windows.length;
-    this._browserSetState = true;
-
-    // We want to re-use the last opened window instead of opening a new one in
-    // the case where it's "empty" and not associated with a window in the session.
-    // We will do more processing via _prepWindowToRestoreInto if we need to use
-    // the lastWindow.
-    let lastWindow = this._getMostRecentBrowserWindow();
-    let canUseLastWindow = lastWindow &&
-                           !lastWindow.__SS_lastSessionWindowID;
-
-    // Restore into windows or open new ones as needed.
-    for (let i = 0; i < lastSessionState.windows.length; i++) {
-      let winState = lastSessionState.windows[i];
-      let lastSessionWindowID = winState.__lastSessionWindowID;
-      // delete lastSessionWindowID so we don't add that to the window again
-      delete winState.__lastSessionWindowID;
-
-      // See if we can use an open window. First try one that is associated with
-      // the state we're trying to restore and then fallback to the last selected
-      // window.
-      let windowToUse = windows[lastSessionWindowID];
-      if (!windowToUse && canUseLastWindow) {
-        windowToUse = lastWindow;
-        canUseLastWindow = false;
-      }
-
-      let [canUseWindow, canOverwriteTabs] = this._prepWindowToRestoreInto(windowToUse);
-
-      // If there's a window already open that we can restore into, use that
-      if (canUseWindow) {
-        // Since we're not overwriting existing tabs, we want to merge _closedTabs,
-        // putting existing ones first. Then make sure we're respecting the max pref.
-        if (winState._closedTabs && winState._closedTabs.length) {
-          let curWinState = this._windows[windowToUse.__SSi];
-          curWinState._closedTabs = curWinState._closedTabs.concat(winState._closedTabs);
-          curWinState._closedTabs.splice(this._prefBranch.getIntPref("sessionstore.max_tabs_undo"), curWinState._closedTabs.length);
-        }
-
-        // Restore into that window - pretend it's a followup since we'll already
-        // have a focused window.
-        //XXXzpao This is going to merge extData together (taking what was in
-        //        winState over what is in the window already. The hack we have
-        //        in _preWindowToRestoreInto will prevent most (all?) Panorama
-        //        weirdness but we will still merge other extData.
-        //        Bug 588217 should make this go away by merging the group data.
-        this.restoreWindow(windowToUse, { windows: [winState] }, canOverwriteTabs, true);
-      }
-      else {
-        this._openWindowWithState({ windows: [winState] });
-      }
-    }
-
-    // Merge closed windows from this session with ones from last session
-    if (lastSessionState._closedWindows) {
-      this._closedWindows = this._closedWindows.concat(lastSessionState._closedWindows);
-      this._capClosedWindows();
-    }
-
-#ifdef MOZ_DEVTOOLS
-    // Scratchpad
-    if (lastSessionState.scratchpads) {
-      ScratchpadManager.restoreSession(lastSessionState.scratchpads);
-    }
-
-    // The Browser Console
-    if (lastSessionState.browserConsole) {
-      HUDService.restoreBrowserConsoleSession();
-    }
-#endif
-
-    // Set data that persists between sessions
-    this._recentCrashes = lastSessionState.session &&
-                          lastSessionState.session.recentCrashes || 0;
-    this._sessionStartTime = lastSessionState.session &&
-                             lastSessionState.session.startTime ||
-                             this._sessionStartTime;
-
-    this._lastSessionState = null;
-  },
-
-  /**
-   * See if aWindow is usable for use when restoring a previous session via
-   * restoreLastSession. If usable, prepare it for use.
-   *
-   * @param aWindow
-   *        the window to inspect & prepare
-   * @returns [canUseWindow, canOverwriteTabs]
-   *          canUseWindow: can the window be used to restore into
-   *          canOverwriteTabs: all of the current tabs are home pages and we
-   *                            can overwrite them
-   */
-  _prepWindowToRestoreInto: function ssi_prepWindowToRestoreInto(aWindow) {
-    if (!aWindow)
-      return [false, false];
-
-    let event = aWindow.document.createEvent("Events");
-    event.initEvent("SSRestoreIntoWindow", true, true);
-
-    // Check if we can use the window.
-    if (!aWindow.dispatchEvent(event))
-      return [false, false];
-
-    // We might be able to overwrite the existing tabs instead of just adding
-    // the previous session's tabs to the end. This will be set if possible.
-    let canOverwriteTabs = false;
-
-    // Look at the open tabs in comparison to home pages. If all the tabs are
-    // home pages then we'll end up overwriting all of them. Otherwise we'll
-    // just close the tabs that match home pages. Tabs with the about:blank
-    // URI will always be overwritten.
-    let homePages = ["about:blank"];
-    let removableTabs = [];
-    let tabbrowser = aWindow.gBrowser;
-    let normalTabsLen = tabbrowser.tabs.length - tabbrowser._numPinnedTabs;
-    let startupPref = this._prefBranch.getIntPref("startup.page");
-    if (startupPref == 1)
-      homePages = homePages.concat(aWindow.gHomeButton.getHomePage().split("|"));
-
-    for (let i = tabbrowser._numPinnedTabs; i < tabbrowser.tabs.length; i++) {
-      let tab = tabbrowser.tabs[i];
-      if (homePages.indexOf(tab.linkedBrowser.currentURI.spec) != -1) {
-        removableTabs.push(tab);
-      }
-    }
-
-    if (tabbrowser.tabs.length == removableTabs.length) {
-      canOverwriteTabs = true;
-    }
-    else {
-      // If we're not overwriting all of the tabs, then close the home tabs.
-      for (let i = removableTabs.length - 1; i >= 0; i--) {
-        tabbrowser.removeTab(removableTabs.pop(), { animate: false });
-      }
-    }
-
-    return [true, canOverwriteTabs];
-  },
-
-  /* ........ Saving Functionality .............. */
-
-  /**
-   * Store all session data for a window
-   * @param aWindow
-   *        Window reference
-   */
-  _saveWindowHistory: function ssi_saveWindowHistory(aWindow) {
-    var tabbrowser = aWindow.gBrowser;
-    var tabs = tabbrowser.tabs;
-    var tabsData = this._windows[aWindow.__SSi].tabs = [];
-
-    for (var i = 0; i < tabs.length; i++)
-      tabsData.push(this._collectTabData(tabs[i]));
-
-    this._windows[aWindow.__SSi].selected = tabbrowser.mTabBox.selectedIndex + 1;
-  },
-
-  /**
-   * Collect data related to a single tab
-   * @param aTab
-   *        tabbrowser tab
-   * @param aFullData
-   *        always return privacy sensitive data (use with care)
-   * @returns object
-   */
-  _collectTabData: function ssi_collectTabData(aTab, aFullData) {
-    var tabData = { entries: [], lastAccessed: aTab.lastAccessed };
-    var browser = aTab.linkedBrowser;
-
-    if (!browser || !browser.currentURI)
-      // can happen when calling this function right after .addTab()
-      return tabData;
-    else if (browser.__SS_data && browser.__SS_tabStillLoading) {
-      // use the data to be restored when the tab hasn't been completely loaded
-      tabData = browser.__SS_data;
-      if (aTab.pinned)
-        tabData.pinned = true;
-      else
-        delete tabData.pinned;
-      tabData.hidden = aTab.hidden;
-
-      // If __SS_extdata is set then we'll use that since it might be newer.
-      if (aTab.__SS_extdata)
-        tabData.extData = aTab.__SS_extdata;
-      // If it exists but is empty then a key was likely deleted. In that case just
-      // delete extData.
-      if (tabData.extData && !Object.keys(tabData.extData).length)
-        delete tabData.extData;
-      return tabData;
-    }
-
-    var history = null;
-    try {
-      history = browser.sessionHistory;
-    }
-    catch (ex) { } // this could happen if we catch a tab during (de)initialization
-
-    // Limit number of back/forward button history entries to save
-    let oldest, newest;
-    let maxSerializeBack = this._prefBranch.getIntPref("sessionstore.max_serialize_back");
-    if (maxSerializeBack >= 0) {
-      oldest = Math.max(0, history.index - maxSerializeBack);
-    } else { // History.getEntryAtIndex(0, ...) is the oldest.
-      oldest = 0;
-    }
-    let maxSerializeFwd = this._prefBranch.getIntPref("sessionstore.max_serialize_forward");
-    if (maxSerializeFwd >= 0) {
-      newest = Math.min(history.count - 1, history.index + maxSerializeFwd);
-    } else { // History.getEntryAtIndex(history.count - 1, ...) is the newest.
-      newest = history.count - 1;
-    }
-
-    // XXXzeniko anchor navigation doesn't reset __SS_data, so we could reuse
-    //           data even when we shouldn't (e.g. Back, different anchor)
-    // Warning: this is required to save form data and scrolling position!
-    if (history && browser.__SS_data &&
-        browser.__SS_data.entries[history.index] &&
-        browser.__SS_data.entries[history.index].url == browser.currentURI.spec &&
-        history.index < this._sessionhistory_max_entries - 1 && !aFullData) {
-      try {
-        tabData.entries = browser.__SS_data.entries.slice(oldest, newest + 1);
-      }
-      catch (ex) {
-        // No errors are expected above, but we use try-catch to keep sessionstore.js safe
-        NS_ASSERT(false, "SessionStore failed to slice history from browser.__SS_data");
-      }
-
-      // Set the one-based index of the currently active tab, ensuring it isn't out of bounds
-      tabData.index = Math.min(history.index - oldest + 1, tabData.entries.length);
-    }
-    else if (history && history.count > 0) {
-      browser.__SS_hostSchemeData = [];
-      try {
-        for (var j = oldest; j <= newest; j++) {
-          let entry = this._serializeHistoryEntry(history.getEntryAtIndex(j, false),
-                                                  aFullData, aTab.pinned, browser.__SS_hostSchemeData);
-          tabData.entries.push(entry);
-        }
-      }
-      catch (ex) {
-        // In some cases, getEntryAtIndex will throw. This seems to be due to
-        // history.count being higher than it should be. By doing this in a
-        // try-catch, we'll update history to where it breaks, assert for
-        // non-release builds, and still save sessionstore.js.
-        NS_ASSERT(false, "SessionStore failed gathering complete history " +
-                         "for the focused window/tab. See bug 669196.");
-      }
-
-      // Set the one-based index of the currently active tab, ensuring it isn't out of bounds
-      tabData.index = Math.min(history.index - oldest + 1, tabData.entries.length);
-
-      // make sure not to cache privacy sensitive data which shouldn't get out
-      if (!aFullData)
-        browser.__SS_data = tabData;
-    }
-    else if (browser.currentURI.spec != "about:blank" ||
-             browser.contentDocument.body.hasChildNodes()) {
-      tabData.entries[0] = { url: browser.currentURI.spec };
-      tabData.index = 1;
-    }
-
-    // If there is a userTypedValue set, then either the user has typed something
-    // in the URL bar, or a new tab was opened with a URI to load. userTypedClear
-    // is used to indicate whether the tab was in some sort of loading state with
-    // userTypedValue.
-    if (browser.userTypedValue) {
-      tabData.userTypedValue = browser.userTypedValue;
-      // We always used to keep track of the loading state as an integer, where
-      // '0' indicated the user had typed since the last load (or no load was
-      // ongoing), and any positive value indicated we had started a load since
-      // the last time the user typed in the URL bar. Mimic this to keep the
-      // session store representation in sync, even though we now represent this
-      // more explicitly:
-      tabData.userTypedClear = browser.didStartLoadSinceLastUserTyping() ? 1 : 0;
-    } else {
-      delete tabData.userTypedValue;
-      delete tabData.userTypedClear;
-    }
-
-    if (aTab.pinned)
-      tabData.pinned = true;
-    else
-      delete tabData.pinned;
-    tabData.hidden = aTab.hidden;
-
-    var disallow = [];
-    for (let cap of gDocShellCapabilities(browser.docShell))
-      if (!browser.docShell["allow" + cap])
-        disallow.push(cap);
-    if (disallow.length > 0)
-      tabData.disallow = disallow.join(",");
-    else if (tabData.disallow)
-      delete tabData.disallow;
-
-    // Save tab attributes.
-    tabData.attributes = TabAttributes.get(aTab);
-
-    // Store the tab icon.
-    let tabbrowser = aTab.ownerDocument.defaultView.gBrowser;
-    tabData.image = tabbrowser.getIcon(aTab);
-
-    if (aTab.__SS_extdata)
-      tabData.extData = aTab.__SS_extdata;
-    else if (tabData.extData)
-      delete tabData.extData;
-
-    if (history && browser.docShell instanceof Ci.nsIDocShell) {
-      let storageData = SessionStorage.serialize(browser.docShell, aFullData)
-      if (Object.keys(storageData).length)
-        tabData.storage = storageData;
-    }
-
-    return tabData;
-  },
-
-  /**
-   * Get an object that is a serialized representation of a History entry
-   * Used for data storage
-   * @param aEntry
-   *        nsISHEntry instance
-   * @param aFullData
-   *        always return privacy sensitive data (use with care)
-   * @param aIsPinned
-   *        the tab is pinned and should be treated differently for privacy
-   * @param aHostSchemeData
-   *        an array of objects with host & scheme keys
-   * @returns object
-   */
-  _serializeHistoryEntry:
-    function ssi_serializeHistoryEntry(aEntry, aFullData, aIsPinned, aHostSchemeData) {
-    var entry = { url: aEntry.URI.spec };
-
-    try {
-      // throwing is expensive, we know that about: pages will throw
-      if (entry.url.indexOf("about:") != 0)
-        aHostSchemeData.push({ host: aEntry.URI.host, scheme: aEntry.URI.scheme });
-    }
-    catch (ex) {
-      // We just won't attempt to get cookies for this entry.
-    }
-
-    if (aEntry.title && aEntry.title != entry.url) {
-      entry.title = aEntry.title;
-    }
-    if (aEntry.isSubFrame) {
-      entry.subframe = true;
-    }
-    if (!(aEntry instanceof Ci.nsISHEntry)) {
-      return entry;
-    }
-
-    var cacheKey = aEntry.cacheKey;
-    if (cacheKey && cacheKey instanceof Ci.nsISupportsPRUint32 &&
-        cacheKey.data != 0) {
-      // XXXbz would be better to have cache keys implement
-      // nsISerializable or something.
-      entry.cacheKey = cacheKey.data;
-    }
-    entry.ID = aEntry.ID;
-    entry.docshellID = aEntry.docshellID;
-
-    if (aEntry.referrerURI)
-      entry.referrer = aEntry.referrerURI.spec;
-
-    if (aEntry.srcdocData)
-      entry.srcdocData = aEntry.srcdocData;
-
-    if (aEntry.isSrcdocEntry)
-      entry.isSrcdocEntry = aEntry.isSrcdocEntry;
-
-    if (aEntry.contentType)
-      entry.contentType = aEntry.contentType;
-
-    var x = {}, y = {};
-    aEntry.getScrollPosition(x, y);
-    if (x.value != 0 || y.value != 0)
-      entry.scroll = x.value + "," + y.value;
-
-    try {
-      var prefPostdata = this._prefBranch.getIntPref("sessionstore.postdata");
-      if (aEntry.postData && (aFullData || prefPostdata &&
-            this.checkPrivacyLevel(aEntry.URI.schemeIs("https"), aIsPinned))) {
-        aEntry.postData.QueryInterface(Ci.nsISeekableStream).
-                        seek(Ci.nsISeekableStream.NS_SEEK_SET, 0);
-        var stream = Cc["@mozilla.org/binaryinputstream;1"].
-                     createInstance(Ci.nsIBinaryInputStream);
-        stream.setInputStream(aEntry.postData);
-        var postBytes = stream.readByteArray(stream.available());
-        var postdata = String.fromCharCode.apply(null, postBytes);
-        if (aFullData || prefPostdata == -1 ||
-            postdata.replace(/^(Content-.*\r\n)+(\r\n)*/, "").length <=
-              prefPostdata) {
-          // We can stop doing base64 encoding once our serialization into JSON
-          // is guaranteed to handle all chars in strings, including embedded
-          // nulls.
-          entry.postdata_b64 = btoa(postdata);
-        }
-      }
-    }
-    catch (ex) { debug(ex); } // POSTDATA is tricky - especially since some extensions don't get it right
-
-    if (aEntry.triggeringPrincipal) {
-      // Not catching anything specific here, just possible errors
-      // from writeCompoundObject and the like.
-      try {
-        var binaryStream = Cc["@mozilla.org/binaryoutputstream;1"].
-                           createInstance(Ci.nsIObjectOutputStream);
-        var pipe = Cc["@mozilla.org/pipe;1"].createInstance(Ci.nsIPipe);
-        pipe.init(false, false, 0, 0xffffffff, null);
-        binaryStream.setOutputStream(pipe.outputStream);
-        binaryStream.writeCompoundObject(aEntry.triggeringPrincipal, Ci.nsIPrincipal, true);
-        binaryStream.close();
-
-        // Now we want to read the data from the pipe's input end and encode it.
-        var scriptableStream = Cc["@mozilla.org/binaryinputstream;1"].
-                               createInstance(Ci.nsIBinaryInputStream);
-        scriptableStream.setInputStream(pipe.inputStream);
-        var triggeringPrincipalBytes =
-          scriptableStream.readByteArray(scriptableStream.available());
-        // We can stop doing base64 encoding once our serialization into JSON
-        // is guaranteed to handle all chars in strings, including embedded
-        // nulls.
-        entry.triggeringPrincipal_b64 = btoa(String.fromCharCode.apply(null, triggeringPrincipalBytes));
-      }
-      catch (ex) { debug(ex); }
-    }
-
-    entry.docIdentifier = aEntry.BFCacheEntry.ID;
-
-    if (aEntry.stateData != null) {
-      entry.structuredCloneState = aEntry.stateData.getDataAsBase64();
-      entry.structuredCloneVersion = aEntry.stateData.formatVersion;
-    }
-
-    if (!(aEntry instanceof Ci.nsISHContainer)) {
-      return entry;
-    }
-
-    if (aEntry.childCount > 0) {
-      let children = [];
-      for (var i = 0; i < aEntry.childCount; i++) {
-        var child = aEntry.GetChildAt(i);
-
-        if (child) {
-          // don't try to restore framesets containing wyciwyg URLs (cf. bug 424689 and bug 450595)
-          if (child.URI.schemeIs("wyciwyg")) {
-            children = [];
-            break;
-          }
-
-          children.push(this._serializeHistoryEntry(child, aFullData,
-                                                    aIsPinned, aHostSchemeData));
-        }
-      }
-
-      if (children.length)
-        entry.children = children;
-    }
-
-    return entry;
-  },
-
-  /**
-   * go through all tabs and store the current scroll positions
-   * and innerHTML content of WYSIWYG editors
-   * @param aWindow
-   *        Window reference
-   */
-  _updateTextAndScrollData: function ssi_updateTextAndScrollData(aWindow) {
-    var browsers = aWindow.gBrowser.browsers;
-    this._windows[aWindow.__SSi].tabs.forEach(function (tabData, i) {
-      try {
-        this._updateTextAndScrollDataForTab(aWindow, browsers[i], tabData);
-      }
-      catch (ex) { debug(ex); } // get as much data as possible, ignore failures (might succeed the next time)
-    }, this);
-  },
-
-  /**
-   * go through all frames and store the current scroll positions
-   * and innerHTML content of WYSIWYG editors
-   * @param aWindow
-   *        Window reference
-   * @param aBrowser
-   *        single browser reference
-   * @param aTabData
-   *        tabData object to add the information to
-   * @param aFullData
-   *        always return privacy sensitive data (use with care)
-   */
-  _updateTextAndScrollDataForTab:
-    function ssi_updateTextAndScrollDataForTab(aWindow, aBrowser, aTabData, aFullData) {
-    // we shouldn't update data for incompletely initialized tabs
-    if (aBrowser.__SS_data && aBrowser.__SS_tabStillLoading)
-      return;
-
-    var tabIndex = (aTabData.index || aTabData.entries.length) - 1;
-    // entry data needn't exist for tabs just initialized with an incomplete session state
-    if (!aTabData.entries[tabIndex])
-      return;
-
-    let selectedPageStyle = aBrowser.markupDocumentViewer.authorStyleDisabled ? "_nostyle" :
-                            this._getSelectedPageStyle(aBrowser.contentWindow);
-    if (selectedPageStyle)
-      aTabData.pageStyle = selectedPageStyle;
-    else if (aTabData.pageStyle)
-      delete aTabData.pageStyle;
-
-    this._updateTextAndScrollDataForFrame(aWindow, aBrowser.contentWindow,
-                                          aTabData.entries[tabIndex],
-                                          !aBrowser.__SS_formDataSaved, aFullData,
-                                          !!aTabData.pinned);
-    aBrowser.__SS_formDataSaved = true;
-    if (aBrowser.currentURI.spec == "about:config")
-      aTabData.entries[tabIndex].formdata = {
-        id: {
-          "textbox": aBrowser.contentDocument.getElementById("textbox").value
-        },
-        xpath: {}
-      };
-  },
-
-  /**
-   * go through all subframes and store all form data, the current
-   * scroll positions and innerHTML content of WYSIWYG editors
-   * @param aWindow
-   *        Window reference
-   * @param aContent
-   *        frame reference
-   * @param aData
-   *        part of a tabData object to add the information to
-   * @param aUpdateFormData
-   *        update all form data for this tab
-   * @param aFullData
-   *        always return privacy sensitive data (use with care)
-   * @param aIsPinned
-   *        the tab is pinned and should be treated differently for privacy
-   */
-  _updateTextAndScrollDataForFrame:
-    function ssi_updateTextAndScrollDataForFrame(aWindow, aContent, aData,
-                                                 aUpdateFormData, aFullData, aIsPinned) {
-    for (var i = 0; i < aContent.frames.length; i++) {
-      if (aData.children && aData.children[i])
-        this._updateTextAndScrollDataForFrame(aWindow, aContent.frames[i],
-                                              aData.children[i], aUpdateFormData,
-                                              aFullData, aIsPinned);
-    }
-    var isHTTPS = this._getURIFromString((aContent.parent || aContent).
-                                         document.location.href).schemeIs("https");
-    let isAboutSR = aContent.top.document.location.href == "about:sessionrestore";
-    if (aFullData || this.checkPrivacyLevel(isHTTPS, aIsPinned) || isAboutSR) {
-      if (aFullData || aUpdateFormData) {
-        let formData = DocumentUtils.getFormData(aContent.document);
-
-        // We want to avoid saving data for about:sessionrestore as a string.
-        // Since it's stored in the form as stringified JSON, stringifying further
-        // causes an explosion of escape characters. cf. bug 467409
-        if (formData && isAboutSR) {
-          formData.id["sessionData"] = JSON.parse(formData.id["sessionData"]);
-        }
-
-        if (Object.keys(formData.id).length ||
-            Object.keys(formData.xpath).length) {
-          aData.formdata = formData;
-        } else if (aData.formdata) {
-          delete aData.formdata;
-        }
-      }
-
-      // designMode is undefined e.g. for XUL documents (as about:config)
-      if ((aContent.document.designMode || "") == "on" && aContent.document.body)
-        aData.innerHTML = aContent.document.body.innerHTML;
-    }
-
-    // get scroll position from nsIDOMWindowUtils, since it allows avoiding a
-    // flush of layout
-    let domWindowUtils = aContent.QueryInterface(Ci.nsIInterfaceRequestor)
-                                 .getInterface(Ci.nsIDOMWindowUtils);
-    let scrollX = {}, scrollY = {};
-    domWindowUtils.getScrollXY(false, scrollX, scrollY);
-    aData.scroll = scrollX.value + "," + scrollY.value;
-  },
-
-  /**
-   * determine the title of the currently enabled style sheet (if any)
-   * and recurse through the frameset if necessary
-   * @param   aContent is a frame reference
-   * @returns the title style sheet determined to be enabled (empty string if none)
-   */
-  _getSelectedPageStyle: function ssi_getSelectedPageStyle(aContent) {
-    const forScreen = /(?:^|,)\s*(?:all|screen)\s*(?:,|$)/i;
-    for (let i = 0; i < aContent.document.styleSheets.length; i++) {
-      let ss = aContent.document.styleSheets[i];
-      let media = ss.media.mediaText;
-      if (!ss.disabled && ss.title && (!media || forScreen.test(media)))
-        return ss.title
-    }
-    for (let i = 0; i < aContent.frames.length; i++) {
-      let selectedPageStyle = this._getSelectedPageStyle(aContent.frames[i]);
-      if (selectedPageStyle)
-        return selectedPageStyle;
-    }
-    return "";
-  },
-
-  /**
-   * extract the base domain from a history entry and its children
-   * @param aEntry
-   *        the history entry, serialized
-   * @param aHosts
-   *        the hash that will be used to store hosts eg, { hostname: true }
-   * @param aCheckPrivacy
-   *        should we check the privacy level for https
-   * @param aIsPinned
-   *        is the entry we're evaluating for a pinned tab; used only if
-   *        aCheckPrivacy
-   */
-  _extractHostsForCookiesFromEntry:
-    function ssi_extractHostsForCookiesFromEntry(aEntry, aHosts, aCheckPrivacy, aIsPinned) {
-
-    let host = aEntry._host,
-        scheme = aEntry._scheme;
-
-    // If host & scheme aren't defined, then we are likely here in the startup
-    // process via _splitCookiesFromWindow. In that case, we'll turn aEntry.url
-    // into an nsIURI and get host/scheme from that. This will throw for about:
-    // urls in which case we don't need to do anything.
-    if (!host && !scheme) {
-      try {
-        let uri = this._getURIFromString(aEntry.url);
-        host = uri.host;
-        scheme = uri.scheme;
-        this._extractHostsForCookiesFromHostScheme(host, scheme, aHosts, aCheckPrivacy, aIsPinned);
-      }
-      catch(ex) { }
-    }
-
-    if (aEntry.children) {
-      aEntry.children.forEach(function(entry) {
-        this._extractHostsForCookiesFromEntry(entry, aHosts, aCheckPrivacy, aIsPinned);
-      }, this);
-    }
-  },
-
-  /**
-   * extract the base domain from a host & scheme
-   * @param aHost
-   *        the host of a uri (usually via nsIURI.host)
-   * @param aScheme
-   *        the scheme of a uri (usually via nsIURI.scheme)
-   * @param aHosts
-   *        the hash that will be used to store hosts eg, { hostname: true }
-   * @param aCheckPrivacy
-   *        should we check the privacy level for https
-   * @param aIsPinned
-   *        is the entry we're evaluating for a pinned tab; used only if
-   *        aCheckPrivacy
-   */
-  _extractHostsForCookiesFromHostScheme:
-    function ssi_extractHostsForCookiesFromHostScheme(aHost, aScheme, aHosts, aCheckPrivacy, aIsPinned) {
-    // host and scheme may not be set (for about: urls for example), in which
-    // case testing scheme will be sufficient.
-    if (/https?/.test(aScheme) && !aHosts[aHost] &&
-        (!aCheckPrivacy ||
-         this.checkPrivacyLevel(aScheme == "https", aIsPinned))) {
-      // By setting this to true or false, we can determine when looking at
-      // the host in _updateCookies if we should check for privacy.
-      aHosts[aHost] = aIsPinned;
-    }
-    else if (aScheme == "file") {
-      aHosts[aHost] = true;
-    }
-  },
-
-  /**
-   * store all hosts for a URL
-   * @param aWindow
-   *        Window reference
-   */
-  _updateCookieHosts: function ssi_updateCookieHosts(aWindow) {
-    var hosts = this._internalWindows[aWindow.__SSi].hosts = {};
-
-    // Since _updateCookiesHosts is only ever called for open windows during a
-    // session, we can call into _extractHostsForCookiesFromHostScheme directly
-    // using data that is attached to each browser.
-    for (let i = 0; i < aWindow.gBrowser.tabs.length; i++) {
-      let tab = aWindow.gBrowser.tabs[i];
-      let hostSchemeData = tab.linkedBrowser.__SS_hostSchemeData || [];
-      for (let j = 0; j < hostSchemeData.length; j++) {
-        this._extractHostsForCookiesFromHostScheme(hostSchemeData[j].host,
-                                                   hostSchemeData[j].scheme,
-                                                   hosts, true, tab.pinned);
-      }
-    }
-  },
-
-  /**
-   * Serialize cookie data
-   * @param aWindows
-   *        JS object containing window data references
-   *        { id: winData, etc. }
-   */
-  _updateCookies: function ssi_updateCookies(aWindows) {
-    function addCookieToHash(aHash, aHost, aPath, aName, aCookie) {
-      // lazily build up a 3-dimensional hash, with
-      // aHost, aPath, and aName as keys
-      if (!aHash[aHost])
-        aHash[aHost] = {};
-      if (!aHash[aHost][aPath])
-        aHash[aHost][aPath] = {};
-      aHash[aHost][aPath][aName] = aCookie;
-    }
-
-    var jscookies = {};
-    var _this = this;
-    // MAX_EXPIRY should be 2^63-1, but JavaScript can't handle that precision
-    var MAX_EXPIRY = Math.pow(2, 62);
-
-    for (let [id, window] in Iterator(aWindows)) {
-      window.cookies = [];
-      let internalWindow = this._internalWindows[id];
-      if (!internalWindow.hosts)
-        return;
-      for (var [host, isPinned] in Iterator(internalWindow.hosts)) {
-        let list;
-        try {
-          list = Services.cookies.getCookiesFromHost(host, {});
-        }
-        catch (ex) {
-          debug("getCookiesFromHost failed. Host: " + host);
-        }
-        while (list && list.hasMoreElements()) {
-          var cookie = list.getNext().QueryInterface(Ci.nsICookie2);
-          // window._hosts will only have hosts with the right privacy rules,
-          // so there is no need to do anything special with this call to
-          // checkPrivacyLevel.
-          if (cookie.isSession && _this.checkPrivacyLevel(cookie.isSecure, isPinned)) {
-            // use the cookie's host, path, and name as keys into a hash,
-            // to make sure we serialize each cookie only once
-            if (!(cookie.host in jscookies &&
-                  cookie.path in jscookies[cookie.host] &&
-                  cookie.name in jscookies[cookie.host][cookie.path])) {
-              var jscookie = { "host": cookie.host, "value": cookie.value };
-              // only add attributes with non-default values (saving a few bits)
-              if (cookie.path) jscookie.path = cookie.path;
-              if (cookie.name) jscookie.name = cookie.name;
-              if (cookie.isSecure) jscookie.secure = true;
-              if (cookie.isHttpOnly) jscookie.httponly = true;
-              if (cookie.expiry < MAX_EXPIRY) jscookie.expiry = cookie.expiry;
-
-              addCookieToHash(jscookies, cookie.host, cookie.path, cookie.name, jscookie);
-            }
-            window.cookies.push(jscookies[cookie.host][cookie.path][cookie.name]);
-          }
-        }
-      }
-
-      // don't include empty cookie sections
-      if (!window.cookies.length)
-        delete window.cookies;
-    }
-  },
-
-  /**
-   * Store window dimensions, visibility, sidebar
-   * @param aWindow
-   *        Window reference
-   */
-  _updateWindowFeatures: function ssi_updateWindowFeatures(aWindow) {
-    var winData = this._windows[aWindow.__SSi];
-
-    WINDOW_ATTRIBUTES.forEach(function(aAttr) {
-      winData[aAttr] = this._getWindowDimension(aWindow, aAttr);
-    }, this);
-
-    var hidden = WINDOW_HIDEABLE_FEATURES.filter(function(aItem) {
-      return aWindow[aItem] && !aWindow[aItem].visible;
-    });
-    if (hidden.length != 0)
-      winData.hidden = hidden.join(",");
-    else if (winData.hidden)
-      delete winData.hidden;
-
-    var sidebar = aWindow.document.getElementById("sidebar-box").getAttribute("sidebarcommand");
-    if (sidebar)
-      winData.sidebar = sidebar;
-    else if (winData.sidebar)
-      delete winData.sidebar;
-  },
-
-  /**
-   * gather session data as object
-   * @param aUpdateAll
-   *        Bool update all windows
-   * @param aPinnedOnly
-   *        Bool collect pinned tabs only
-   * @returns object
-   */
-  _getCurrentState: function ssi_getCurrentState(aUpdateAll, aPinnedOnly) {
-    this._handleClosedWindows();
-
-    var activeWindow = this._getMostRecentBrowserWindow();
-
-    if (this._loadState == STATE_RUNNING) {
-      // update the data for all windows with activities since the last save operation
-      this._forEachBrowserWindow(function(aWindow) {
-        if (!this._isWindowLoaded(aWindow)) // window data is still in _statesToRestore
-          return;
-        if (aUpdateAll || this._dirtyWindows[aWindow.__SSi] || aWindow == activeWindow) {
-          this._collectWindowData(aWindow);
-        }
-        else { // always update the window features (whose change alone never triggers a save operation)
-          this._updateWindowFeatures(aWindow);
-        }
-      });
-      this._dirtyWindows = [];
-    }
-
-    // collect the data for all windows
-    var total = [], windows = {}, ids = [];
-    var nonPopupCount = 0;
-    var ix;
-    for (ix in this._windows) {
-      if (this._windows[ix]._restoring) // window data is still in _statesToRestore
-        continue;
-      total.push(this._windows[ix]);
-      ids.push(ix);
-      windows[ix] = this._windows[ix];
-      if (!this._windows[ix].isPopup)
-        nonPopupCount++;
-    }
-    this._updateCookies(windows);
-
-    // collect the data for all windows yet to be restored
-    for (ix in this._statesToRestore) {
-      for each (let winData in this._statesToRestore[ix].windows) {
-        total.push(winData);
-        if (!winData.isPopup)
-          nonPopupCount++;
-      }
-    }
-
-    // shallow copy this._closedWindows to preserve current state
-    let lastClosedWindowsCopy = this._closedWindows.slice();
-
-#ifndef XP_MACOSX
-    // If no non-popup browser window remains open, return the state of the last
-    // closed window(s). We only want to do this when we're actually "ending"
-    // the session.
-    //XXXzpao We should do this for _restoreLastWindow == true, but that has
-    //        its own check for popups. c.f. bug 597619
-    if (nonPopupCount == 0 && lastClosedWindowsCopy.length > 0 &&
-        this._loadState == STATE_QUITTING) {
-      // prepend the last non-popup browser window, so that if the user loads more tabs
-      // at startup we don't accidentally add them to a popup window
-      do {
-        total.unshift(lastClosedWindowsCopy.shift())
-      } while (total[0].isPopup && lastClosedWindowsCopy.length > 0)
-    }
-#endif
-
-    if (aPinnedOnly) {
-      // perform a deep copy so that existing session variables are not changed.
-      total = JSON.parse(this._toJSONString(total));
-      total = total.filter(function (win) {
-        win.tabs = win.tabs.filter(function (tab) tab.pinned);
-        // remove closed tabs
-        win._closedTabs = [];
-        // correct selected tab index if it was stripped out
-        if (win.selected > win.tabs.length)
-          win.selected = 1;
-        return win.tabs.length > 0;
-      });
-      if (total.length == 0)
-        return null;
-
-      lastClosedWindowsCopy = [];
-    }
-
-    if (activeWindow) {
-      this.activeWindowSSiCache = activeWindow.__SSi || "";
-    }
-    ix = ids.indexOf(this.activeWindowSSiCache);
-    // We don't want to restore focus to a minimized window or a window which had all its
-    // tabs stripped out (doesn't exist).
-    if (ix != -1 && total[ix] && total[ix].sizemode == "minimized")
-      ix = -1;
-
-    let session = {
-      state: this._loadState == STATE_RUNNING ? STATE_RUNNING_STR : STATE_STOPPED_STR,
-      lastUpdate: Date.now(),
-      startTime: this._sessionStartTime,
-      recentCrashes: this._recentCrashes
-    };
-
-    var scratchpads = null;
-    var browserConsole = null;
-#ifdef MOZ_DEVTOOLS
-    // Scratchpad
-    // get open Scratchpad window states too
-    scratchpads = ScratchpadManager.getSessionState();
-
-    // The Browser Console
-    browserConsole = HUDService.getBrowserConsoleSessionState();
-#endif
-
-    return {
-      windows: total,
-      selectedWindow: ix + 1,
-      _closedWindows: lastClosedWindowsCopy,
-#ifdef MOZ_DEVTOOLS
-      session: session,
-      scratchpads: scratchpads,
-      browserConsole: browserConsole
-#else
-      session: session
-#endif
-    };
-  },
-
-  /**
-   * serialize session data for a window
-   * @param aWindow
-   *        Window reference
-   * @returns string
-   */
-  _getWindowState: function ssi_getWindowState(aWindow) {
-    if (!this._isWindowLoaded(aWindow))
-      return this._statesToRestore[aWindow.__SS_restoreID];
-
-    if (this._loadState == STATE_RUNNING) {
-      this._collectWindowData(aWindow);
-    }
-
-    var winData = this._windows[aWindow.__SSi];
-    let windows = {};
-    windows[aWindow.__SSi] = winData;
-    this._updateCookies(windows);
-
-    return { windows: [winData] };
-  },
-
-  _collectWindowData: function ssi_collectWindowData(aWindow) {
-    if (!this._isWindowLoaded(aWindow))
-      return;
-
-    // update the internal state data for this window
-    this._saveWindowHistory(aWindow);
-    this._updateTextAndScrollData(aWindow);
-    this._updateCookieHosts(aWindow);
-    this._updateWindowFeatures(aWindow);
-
-    // Make sure we keep __SS_lastSessionWindowID around for cases like entering
-    // or leaving PB mode.
-    if (aWindow.__SS_lastSessionWindowID)
-      this._windows[aWindow.__SSi].__lastSessionWindowID =
-        aWindow.__SS_lastSessionWindowID;
-
-    this._dirtyWindows[aWindow.__SSi] = false;
-  },
-
-  /* ........ Restoring Functionality .............. */
-
-  /**
-   * restore features to a single window
-   * @param aWindow
-   *        Window reference
-   * @param aState
-   *        JS object or its eval'able source
-   * @param aOverwriteTabs
-   *        bool overwrite existing tabs w/ new ones
-   * @param aFollowUp
-   *        bool this isn't the restoration of the first window
-   */
-  restoreWindow: function ssi_restoreWindow(aWindow, aState, aOverwriteTabs, aFollowUp) {
-    if (!aFollowUp) {
-      this.windowToFocus = aWindow;
-    }
-    // initialize window if necessary
-    if (aWindow && (!aWindow.__SSi || !this._windows[aWindow.__SSi]))
-      this.onLoad(aWindow);
-
-    try {
-      var root = typeof aState == "string" ? JSON.parse(aState) : aState;
-      if (!root.windows[0]) {
-        this._sendRestoreCompletedNotifications();
-        return; // nothing to restore
-      }
-    }
-    catch (ex) { // invalid state object - don't restore anything
-      debug(ex);
-      this._sendRestoreCompletedNotifications();
-      return;
-    }
-
-    // We're not returning from this before we end up calling restoreHistoryPrecursor
-    // for this window, so make sure we send the SSWindowStateBusy event.
-    this._setWindowStateBusy(aWindow);
-
-    if (root._closedWindows)
-      this._closedWindows = root._closedWindows;
-
-    var winData;
-    if (!root.selectedWindow || root.selectedWindow > root.windows.length) {
-      root.selectedWindow = 0;
-    }
-
-    // open new windows for all further window entries of a multi-window session
-    // (unless they don't contain any tab data)
-    for (var w = 1; w < root.windows.length; w++) {
-      winData = root.windows[w];
-      if (winData && winData.tabs && winData.tabs[0]) {
-        var window = this._openWindowWithState({ windows: [winData] });
-        if (w == root.selectedWindow - 1) {
-          this.windowToFocus = window;
-        }
-      }
-    }
-    winData = root.windows[0];
-    if (!winData.tabs) {
-      winData.tabs = [];
-    }
-    // don't restore a single blank tab when we've had an external
-    // URL passed in for loading at startup (cf. bug 357419)
-    else if (root._firstTabs && !aOverwriteTabs && winData.tabs.length == 1 &&
-             (!winData.tabs[0].entries || winData.tabs[0].entries.length == 0)) {
-      winData.tabs = [];
-    }
-
-    var tabbrowser = aWindow.gBrowser;
-    var openTabCount = aOverwriteTabs ? tabbrowser.browsers.length : -1;
-    var newTabCount = winData.tabs.length;
-    var tabs = [];
-
-    // disable smooth scrolling while adding, moving, removing and selecting tabs
-    var tabstrip = tabbrowser.tabContainer.mTabstrip;
-    var smoothScroll = tabstrip.smoothScroll;
-    tabstrip.smoothScroll = false;
-
-    // unpin all tabs to ensure they are not reordered in the next loop
-    if (aOverwriteTabs) {
-      for (let t = tabbrowser._numPinnedTabs - 1; t > -1; t--)
-        tabbrowser.unpinTab(tabbrowser.tabs[t]);
-    }
-
-    // make sure that the selected tab won't be closed in order to
-    // prevent unnecessary flickering
-    if (aOverwriteTabs && tabbrowser.selectedTab._tPos >= newTabCount)
-      tabbrowser.moveTabTo(tabbrowser.selectedTab, newTabCount - 1);
-
-    let numVisibleTabs = 0;
-
-    for (var t = 0; t < newTabCount; t++) {
-      tabs.push(t < openTabCount ?
-                tabbrowser.tabs[t] :
-                tabbrowser.addTab("about:blank",
-                                  {skipAnimation: true,
-                                   skipBackgroundNotify: true}));
-      // when resuming at startup: add additionally requested pages to the end
-      if (!aOverwriteTabs && root._firstTabs) {
-        tabbrowser.moveTabTo(tabs[t], t);
-      }
-
-      if (winData.tabs[t].pinned)
-        tabbrowser.pinTab(tabs[t]);
-
-      if (winData.tabs[t].hidden) {
-        tabbrowser.hideTab(tabs[t]);
-      }
-      else {
-        tabbrowser.showTab(tabs[t]);
-        numVisibleTabs++;
-      }
-    }
-
-    // if all tabs to be restored are hidden, make the first one visible
-    if (!numVisibleTabs && winData.tabs.length) {
-      winData.tabs[0].hidden = false;
-      tabbrowser.showTab(tabs[0]);
-    }
-
-    // If overwriting tabs, we want to reset each tab's "restoring" state. Since
-    // we're overwriting those tabs, they should no longer be restoring. The
-    // tabs will be rebuilt and marked if they need to be restored after loading
-    // state (in restoreHistoryPrecursor).
-    if (aOverwriteTabs) {
-      for (let i = 0; i < tabbrowser.tabs.length; i++) {
-        if (tabbrowser.browsers[i].__SS_restoreState)
-          this._resetTabRestoringState(tabbrowser.tabs[i]);
-      }
-    }
-
-    // We want to set up a counter on the window that indicates how many tabs
-    // in this window are unrestored. This will be used in restoreNextTab to
-    // determine if gRestoreTabsProgressListener should be removed from the window.
-    // If we aren't overwriting existing tabs, then we want to add to the existing
-    // count in case there are still tabs restoring.
-    if (!aWindow.__SS_tabsToRestore)
-      aWindow.__SS_tabsToRestore = 0;
-    if (aOverwriteTabs)
-      aWindow.__SS_tabsToRestore = newTabCount;
-    else
-      aWindow.__SS_tabsToRestore += newTabCount;
-
-    // We want to correlate the window with data from the last session, so
-    // assign another id if we have one. Otherwise clear so we don't do
-    // anything with it.
-    delete aWindow.__SS_lastSessionWindowID;
-    if (winData.__lastSessionWindowID)
-      aWindow.__SS_lastSessionWindowID = winData.__lastSessionWindowID;
-
-    // when overwriting tabs, remove all superflous ones
-    if (aOverwriteTabs && newTabCount < openTabCount) {
-      Array.slice(tabbrowser.tabs, newTabCount, openTabCount)
-           .forEach(tabbrowser.removeTab, tabbrowser);
-    }
-
-    if (aOverwriteTabs) {
-      this.restoreWindowFeatures(aWindow, winData);
-      delete this._windows[aWindow.__SSi].extData;
-    }
-    if (winData.cookies) {
-      this.restoreCookies(winData.cookies);
-    }
-    if (winData.extData) {
-      if (!this._windows[aWindow.__SSi].extData) {
-        this._windows[aWindow.__SSi].extData = {};
-      }
-      for (var key in winData.extData) {
-        this._windows[aWindow.__SSi].extData[key] = winData.extData[key];
-      }
-    }
-    if (aOverwriteTabs || root._firstTabs) {
-      this._windows[aWindow.__SSi]._closedTabs = winData._closedTabs || [];
-    }
-
-    this.restoreHistoryPrecursor(aWindow, tabs, winData.tabs,
-      (aOverwriteTabs ? (parseInt(winData.selected) || 1) : 0), 0, 0);
-
-#ifdef MOZ_DEVTOOLS
-    if (aState.scratchpads) {
-      ScratchpadManager.restoreSession(aState.scratchpads);
-    }
-
-    // The Browser Console
-    if (aState.browserConsole) {
-      HUDService.restoreBrowserConsoleSession();
-    }
-
-#endif
-    // set smoothScroll back to the original value
-    tabstrip.smoothScroll = smoothScroll;
-
-    this._sendRestoreCompletedNotifications();
-  },
-
-  /**
-   * Sets the tabs restoring order with the following priority:
-   * Selected tab, pinned tabs, optimized visible tabs, other visible tabs and
-   * hidden tabs.
-   * @param aTabBrowser
-   *        Tab browser object
-   * @param aTabs
-   *        Array of tab references
-   * @param aTabData
-   *        Array of tab data
-   * @param aSelectedTab
-   *        Index of selected tab (1 is first tab, 0 no selected tab)
-   */
-  _setTabsRestoringOrder : function ssi__setTabsRestoringOrder(
-    aTabBrowser, aTabs, aTabData, aSelectedTab) {
-
-    // Store the selected tab. Need to substract one to get the index in aTabs.
-    let selectedTab;
-    if (aSelectedTab > 0 && aTabs[aSelectedTab - 1]) {
-      selectedTab = aTabs[aSelectedTab - 1];
-    }
-
-    // Store the pinned tabs and hidden tabs.
-    let pinnedTabs = [];
-    let pinnedTabsData = [];
-    let hiddenTabs = [];
-    let hiddenTabsData = [];
-    if (aTabs.length > 1) {
-      for (let t = aTabs.length - 1; t >= 0; t--) {
-        if (aTabData[t].pinned) {
-          pinnedTabs.unshift(aTabs.splice(t, 1)[0]);
-          pinnedTabsData.unshift(aTabData.splice(t, 1)[0]);
-        } else if (aTabData[t].hidden) {
-          hiddenTabs.unshift(aTabs.splice(t, 1)[0]);
-          hiddenTabsData.unshift(aTabData.splice(t, 1)[0]);
-        }
-      }
-    }
-
-    // Optimize the visible tabs only if there is a selected tab.
-    if (selectedTab) {
-      let selectedTabIndex = aTabs.indexOf(selectedTab);
-      if (selectedTabIndex > 0) {
-        let scrollSize = aTabBrowser.tabContainer.mTabstrip.scrollClientSize;
-        let tabWidth = aTabs[0].getBoundingClientRect().width;
-        let maxVisibleTabs = Math.ceil(scrollSize / tabWidth);
-        if (maxVisibleTabs < aTabs.length) {
-          let firstVisibleTab = 0;
-          let nonVisibleTabsCount = aTabs.length - maxVisibleTabs;
-          if (nonVisibleTabsCount >= selectedTabIndex) {
-            // Selected tab is leftmost since we scroll to it when possible.
-            firstVisibleTab = selectedTabIndex;
-          } else {
-            // Selected tab is rightmost or no more room to scroll right.
-            firstVisibleTab = nonVisibleTabsCount;
-          }
-          aTabs = aTabs.splice(firstVisibleTab, maxVisibleTabs).concat(aTabs);
-          aTabData =
-            aTabData.splice(firstVisibleTab, maxVisibleTabs).concat(aTabData);
-        }
-      }
-    }
-
-    // Merge the stored tabs in order.
-    aTabs = pinnedTabs.concat(aTabs, hiddenTabs);
-    aTabData = pinnedTabsData.concat(aTabData, hiddenTabsData);
-
-    // Load the selected tab to the first position and select it.
-    if (selectedTab) {
-      let selectedTabIndex = aTabs.indexOf(selectedTab);
-      if (selectedTabIndex > 0) {
-        aTabs = aTabs.splice(selectedTabIndex, 1).concat(aTabs);
-        aTabData = aTabData.splice(selectedTabIndex, 1).concat(aTabData);
-      }
-      aTabBrowser.selectedTab = selectedTab;
-    }
-
-    return [aTabs, aTabData];
-  },
-  
-  /**
-   * Manage history restoration for a window
-   * @param aWindow
-   *        Window to restore the tabs into
-   * @param aTabs
-   *        Array of tab references
-   * @param aTabData
-   *        Array of tab data
-   * @param aSelectTab
-   *        Index of selected tab
-   * @param aIx
-   *        Index of the next tab to check readyness for
-   * @param aCount
-   *        Counter for number of times delaying b/c browser or history aren't ready
-   * @param aRestoreImmediately
-   *        Flag to indicate whether the given set of tabs aTabs should be
-   *        restored/loaded immediately even if restore_on_demand = true
-   */
-  restoreHistoryPrecursor:
-    function ssi_restoreHistoryPrecursor(aWindow, aTabs, aTabData, aSelectTab,
-                                         aIx, aCount, aRestoreImmediately = false) {
-    var tabbrowser = aWindow.gBrowser;
-
-    // make sure that all browsers and their histories are available
-    // - if one's not, resume this check in 100ms (repeat at most 10 times)
-    for (var t = aIx; t < aTabs.length; t++) {
-      try {
-        if (!tabbrowser.getBrowserForTab(aTabs[t]).webNavigation.sessionHistory) {
-          throw new Error();
-        }
-      }
-      catch (ex) { // in case browser or history aren't ready yet
-        if (aCount < 10) {
-          var restoreHistoryFunc = function(self) {
-            self.restoreHistoryPrecursor(aWindow, aTabs, aTabData, aSelectTab,
-                                         aIx, aCount + 1, aRestoreImmediately);
-          }
-          aWindow.setTimeout(restoreHistoryFunc, 100, this);
-          return;
-        }
-      }
-    }
-
-    if (!this._isWindowLoaded(aWindow)) {
-      // from now on, the data will come from the actual window
-      delete this._statesToRestore[aWindow.__SS_restoreID];
-      delete aWindow.__SS_restoreID;
-      delete this._windows[aWindow.__SSi]._restoring;
-
-      // It's important to set the window state to dirty so that
-      // we collect their data for the first time when saving state.
-      this._dirtyWindows[aWindow.__SSi] = true;
-    }
-
-    if (aTabs.length == 0) {
-      // this is normally done in restoreHistory() but as we're returning early
-      // here we need to take care of it.
-      this._setWindowStateReady(aWindow);
-      return;
-    }
-
-    // Sets the tabs restoring order. 
-    [aTabs, aTabData] =
-      this._setTabsRestoringOrder(tabbrowser, aTabs, aTabData, aSelectTab);
-
-    // Prepare the tabs so that they can be properly restored. We'll pin/unpin
-    // and show/hide tabs as necessary. We'll also set the labels, user typed
-    // value, and attach a copy of the tab's data in case we close it before
-    // it's been restored.
-    for (t = 0; t < aTabs.length; t++) {
-      let tab = aTabs[t];
-      let browser = tabbrowser.getBrowserForTab(tab);
-      let tabData = aTabData[t];
-
-      if (tabData.pinned)
-        tabbrowser.pinTab(tab);
-      else
-        tabbrowser.unpinTab(tab);
-
-      if (tabData.hidden)
-        tabbrowser.hideTab(tab);
-      else
-        tabbrowser.showTab(tab);
-
-      if ("attributes" in tabData) {
-        // Ensure that we persist tab attributes restored from previous sessions.
-        Object.keys(tabData.attributes).forEach(a => TabAttributes.persist(a));
-      }
-
-      browser.__SS_tabStillLoading = true;
-
-      // keep the data around to prevent dataloss in case
-      // a tab gets closed before it's been properly restored
-      browser.__SS_data = tabData;
-      browser.__SS_restoreState = TAB_STATE_NEEDS_RESTORE;
-      browser.setAttribute("pending", "true");
-      tab.setAttribute("pending", "true");
-
-      // Make sure that set/getTabValue will set/read the correct data by
-      // wiping out any current value in tab.__SS_extdata.
-      delete tab.__SS_extdata;
-
-      if (!tabData.entries || tabData.entries.length == 0) {
-        // make sure to blank out this tab's content
-        // (just purging the tab's history won't be enough)
-        browser.contentDocument.location = "about:blank";
-        continue;
-      }
-
-      browser.stop(); // in case about:blank isn't done yet
-
-      // wall-paper fix for bug 439675: make sure that the URL to be loaded
-      // is always visible in the address bar
-      let activeIndex = (tabData.index || tabData.entries.length) - 1;
-      let activePageData = tabData.entries[activeIndex] || null;
-      let uri = activePageData ? activePageData.url || null : null;
-      browser.userTypedValue = uri;
-
-      // Also make sure currentURI is set so that switch-to-tab works before
-      // the tab is restored. We'll reset this to about:blank when we try to
-      // restore the tab to ensure that docshell doeesn't get confused.
-      if (uri)
-        browser.docShell.setCurrentURI(this._getURIFromString(uri));
-
-      // If the page has a title, set it.
-      if (activePageData) {
-        if (activePageData.title) {
-          tab.label = activePageData.title;
-          tab.crop = "end";
-        } else if (activePageData.url != "about:blank") {
-          tab.label = activePageData.url;
-          tab.crop = "center";
-        }
-      }
-    }
-
-    // helper hashes for ensuring unique frame IDs and unique document
-    // identifiers.
-    var idMap = { used: {} };
-    var docIdentMap = {};
-    this.restoreHistory(aWindow, aTabs, aTabData, idMap, docIdentMap,
-                        aRestoreImmediately);
-  },
-
-  /**
-   * Restore history for a window
-   * @param aWindow
-   *        Window reference
-   * @param aTabs
-   *        Array of tab references
-   * @param aTabData
-   *        Array of tab data
-   * @param aIdMap
-   *        Hash for ensuring unique frame IDs
-   * @param aRestoreImmediately
-   *        Flag to indicate whether the given set of tabs aTabs should be
-   *        restored/loaded immediately even if restore_on_demand = true
-   */
-  restoreHistory:
-    function ssi_restoreHistory(aWindow, aTabs, aTabData, aIdMap, aDocIdentMap,
-                                aRestoreImmediately) {
-    var _this = this;
-    // if the tab got removed before being completely restored, then skip it
-    while (aTabs.length > 0 && !(this._canRestoreTabHistory(aTabs[0]))) {
-      aTabs.shift();
-      aTabData.shift();
-    }
-    if (aTabs.length == 0) {
-      // At this point we're essentially ready for consumers to read/write data
-      // via the sessionstore API so we'll send the SSWindowStateReady event.
-      this._setWindowStateReady(aWindow);
-      return; // no more tabs to restore
-    }
-
-    var tab = aTabs.shift();
-    var tabData = aTabData.shift();
-
-    var browser = aWindow.gBrowser.getBrowserForTab(tab);
-    var history = browser.webNavigation.sessionHistory;
-
-    if (history.count > 0) {
-      history.PurgeHistory(history.count);
-    }
-    history.QueryInterface(Ci.nsISHistoryInternal);
-
-    browser.__SS_shistoryListener = new SessionStoreSHistoryListener(tab);
-    history.addSHistoryListener(browser.__SS_shistoryListener);
-
-    if (!tabData.entries) {
-      tabData.entries = [];
-    }
-    if (tabData.extData) {
-      tab.__SS_extdata = {};
-      for (let key in tabData.extData)
-        tab.__SS_extdata[key] = tabData.extData[key];
-    }
-    else
-      delete tab.__SS_extdata;
-
-    for (var i = 0; i < tabData.entries.length; i++) {
-      //XXXzpao Wallpaper patch for bug 514751
-      if (!tabData.entries[i].url)
-        continue;
-      history.addEntry(this._deserializeHistoryEntry(tabData.entries[i],
-                                                     aIdMap, aDocIdentMap), true);
-    }
-
-    // make sure to reset the capabilities and attributes, in case this tab gets reused
-    let disallow = new Set(tabData.disallow && tabData.disallow.split(","));
-    for (let cap of gDocShellCapabilities(browser.docShell))
-      browser.docShell["allow" + cap] = !disallow.has(cap);
-
-    // Restore tab attributes.
-    if ("attributes" in tabData) {
-      TabAttributes.set(tab, tabData.attributes);
-    }
-
-    // Restore the tab icon.
-    if ("image" in tabData) {
-      // Using null as the loadingPrincipal because serializing
-      // the principal would be overkill. Within SetIcon we
-      // default to the systemPrincipal if aLoadingPrincipal is
-      // null which will allow the favicon to load.
-      aWindow.gBrowser.setIcon(tab, tabData.image, null);
-    }
-
-    if (tabData.storage && browser.docShell instanceof Ci.nsIDocShell)
-      SessionStorage.deserialize(browser.docShell, tabData.storage);
-
-    // notify the tabbrowser that the tab chrome has been restored
-    var event = aWindow.document.createEvent("Events");
-    event.initEvent("SSTabRestoring", true, false);
-    tab.dispatchEvent(event);
-
-    // Restore the history in the next tab
-    aWindow.setTimeout(function(){
-      _this.restoreHistory(aWindow, aTabs, aTabData, aIdMap, aDocIdentMap,
-                           aRestoreImmediately);
-    }, 0);
-
-    // This could cause us to ignore max_concurrent_tabs pref a bit, but
-    // it ensures each window will have its selected tab loaded.
-    if (aRestoreImmediately || aWindow.gBrowser.selectedBrowser == browser) {
-      this.restoreTab(tab);
-    }
-    else {
-      TabRestoreQueue.add(tab);
-      this.restoreNextTab();
-    }
-  },
-
-  /**
-   * Restores the specified tab. If the tab can't be restored (eg, no history or
-   * calling gotoIndex fails), then state changes will be rolled back.
-   * This method will check if gTabsProgressListener is attached to the tab's
-   * window, ensuring that we don't get caught without one.
-   * This method removes the session history listener right before starting to
-   * attempt a load. This will prevent cases of "stuck" listeners.
-   * If this method returns false, then it is up to the caller to decide what to
-   * do. In the common case (restoreNextTab), we will want to then attempt to
-   * restore the next tab. In the other case (selecting the tab, reloading the
-   * tab), the caller doesn't actually want to do anything if no page is loaded.
-   *
-   * @param aTab
-   *        the tab to restore
-   *
-   * @returns true/false indicating whether or not a load actually happened
-   */
-  restoreTab: function ssi_restoreTab(aTab) {
-    let window = aTab.ownerDocument.defaultView;
-    let browser = aTab.linkedBrowser;
-    let tabData = browser.__SS_data;
-
-    // There are cases within where we haven't actually started a load. In that
-    // that case we'll reset state changes we made and return false to the caller
-    // can handle appropriately.
-    let didStartLoad = false;
-
-    // Make sure that the tabs progress listener is attached to this window
-    this._ensureTabsProgressListener(window);
-
-    // Make sure that this tab is removed from the priority queue.
-    TabRestoreQueue.remove(aTab);
-
-    // Increase our internal count.
-    this._tabsRestoringCount++;
-
-    // Set this tab's state to restoring
-    browser.__SS_restoreState = TAB_STATE_RESTORING;
-    browser.removeAttribute("pending");
-    aTab.removeAttribute("pending");
-
-    // Remove the history listener, since we no longer need it once we start restoring
-    this._removeSHistoryListener(aTab);
-
-    let activeIndex = (tabData.index || tabData.entries.length) - 1;
-    if (activeIndex >= tabData.entries.length)
-      activeIndex = tabData.entries.length - 1;
-    // Reset currentURI.  This creates a new session history entry with a new
-    // doc identifier, so we need to explicitly save and restore the old doc
-    // identifier (corresponding to the SHEntry at activeIndex) below.
-    browser.webNavigation.setCurrentURI(this._getURIFromString("about:blank"));
-    // Attach data that will be restored on "load" event, after tab is restored.
-    if (activeIndex > -1) {
-      // restore those aspects of the currently active documents which are not
-      // preserved in the plain history entries (mainly scroll state and text data)
-      browser.__SS_restore_data = tabData.entries[activeIndex] || {};
-      browser.__SS_restore_pageStyle = tabData.pageStyle || "";
-      browser.__SS_restore_tab = aTab;
-      didStartLoad = true;
-      try {
-        // In order to work around certain issues in session history, we need to
-        // force session history to update its internal index and call reload
-        // instead of gotoIndex. See bug 597315.
-        browser.webNavigation.sessionHistory.getEntryAtIndex(activeIndex, true);
-        browser.webNavigation.sessionHistory.reloadCurrentEntry();
-        // If the user prefers it, bypass cache and always load from the network.
-        let flags = Ci.nsIWebNavigation.LOAD_FLAGS_NONE;
-        switch (this._cacheBehavior) {
-          case 2: // hard refresh
-            flags = Ci.nsIWebNavigation.LOAD_FLAGS_BYPASS_PROXY |
-                    Ci.nsIWebNavigation.LOAD_FLAGS_BYPASS_CACHE;
-            browser.webNavigation.reload(flags);
-            break;
-          case 1: // soft refresh
-            browser.webNavigation.reload(flags);
-            break;
-          default: // 0 or other: use cache, so do nothing.
-            break;
-        }
-      }
-      catch (ex) {
-        // ignore page load errors
-        aTab.removeAttribute("busy");
-        didStartLoad = false;
-      }
-    }
-
-    // Handle userTypedValue. Setting userTypedValue seems to update gURLbar
-    // as needed. Calling loadURI will cancel form filling in restoreDocument
-    if (tabData.userTypedValue) {
-      browser.userTypedValue = tabData.userTypedValue;
-      if (tabData.userTypedClear) {
-        // Make it so that we'll enter restoreDocument on page load. We will
-        // fire SSTabRestored from there. We don't have any form data to restore
-        // so we can just set the URL to null.
-        browser.__SS_restore_data = { url: null };
-        browser.__SS_restore_tab = aTab;
-        if (didStartLoad)
-          browser.stop();
-        didStartLoad = true;
-        browser.loadURIWithFlags(tabData.userTypedValue,
-                                 Ci.nsIWebNavigation.LOAD_FLAGS_ALLOW_THIRD_PARTY_FIXUP);
-      }
-    }
-
-    // If we didn't start a load, then we won't reset this tab through the usual
-    // channel (via the progress listener), so reset the tab ourselves. We will
-    // also send SSTabRestored since this tab has technically been restored.
-    if (!didStartLoad) {
-      this._sendTabRestoredNotification(aTab);
-      this._resetTabRestoringState(aTab);
-    }
-
-    return didStartLoad;
-  },
-
-  /**
-   * This _attempts_ to restore the next available tab. If the restore fails,
-   * then we will attempt the next one.
-   * There are conditions where this won't do anything:
-   *   if we're in the process of quitting
-   *   if there are no tabs to restore
-   *   if we have already reached the limit for number of tabs to restore
-   */
-  restoreNextTab: function ssi_restoreNextTab() {
-    // If we call in here while quitting, we don't actually want to do anything
-    if (this._loadState == STATE_QUITTING)
-      return;
-
-    // Don't exceed the maximum number of concurrent tab restores.
-    if (this._tabsRestoringCount >= this._maxConcurrentTabRestores)
-      return;
-
-    let tab = TabRestoreQueue.shift();
-    if (tab) {
-      let didStartLoad = this.restoreTab(tab);
-      // If we don't start a load in the restored tab (eg, no entries) then we
-      // want to attempt to restore the next tab.
-      if (!didStartLoad)
-        this.restoreNextTab();
-    }
-  },
-
-  /**
-   * expands serialized history data into a session-history-entry instance
-   * @param aEntry
-   *        Object containing serialized history data for a URL
-   * @param aIdMap
-   *        Hash for ensuring unique frame IDs
-   * @returns nsISHEntry
-   */
-  _deserializeHistoryEntry:
-    function ssi_deserializeHistoryEntry(aEntry, aIdMap, aDocIdentMap) {
-
-    var shEntry = Cc["@mozilla.org/browser/session-history-entry;1"].
-                  createInstance(Ci.nsISHEntry);
-
-    shEntry.setURI(this._getURIFromString(aEntry.url));
-    shEntry.setTitle(aEntry.title || aEntry.url);
-    if (aEntry.subframe)
-      shEntry.setIsSubFrame(aEntry.subframe || false);
-    shEntry.loadType = Ci.nsIDocShellLoadInfo.loadHistory;
-    if (aEntry.contentType)
-      shEntry.contentType = aEntry.contentType;
-    if (aEntry.referrer)
-      shEntry.referrerURI = this._getURIFromString(aEntry.referrer);
-    if (aEntry.isSrcdocEntry)
-      shEntry.srcdocData = aEntry.srcdocData;
-
-    if (aEntry.cacheKey) {
-      var cacheKey = Cc["@mozilla.org/supports-PRUint32;1"].
-                     createInstance(Ci.nsISupportsPRUint32);
-      cacheKey.data = aEntry.cacheKey;
-      shEntry.cacheKey = cacheKey;
-    }
-
-    if (aEntry.ID) {
-      // get a new unique ID for this frame (since the one from the last
-      // start might already be in use)
-      var id = aIdMap[aEntry.ID] || 0;
-      if (!id) {
-        for (id = Date.now(); id in aIdMap.used; id++);
-        aIdMap[aEntry.ID] = id;
-        aIdMap.used[id] = true;
-      }
-      shEntry.ID = id;
-    }
-
-    if (aEntry.docshellID)
-      shEntry.docshellID = aEntry.docshellID;
-
-    if (aEntry.structuredCloneState && aEntry.structuredCloneVersion) {
-      shEntry.stateData =
-        Cc["@mozilla.org/docshell/structured-clone-container;1"].
-        createInstance(Ci.nsIStructuredCloneContainer);
-
-      shEntry.stateData.initFromBase64(aEntry.structuredCloneState,
-                                       aEntry.structuredCloneVersion);
-    }
-
-    if (aEntry.scroll) {
-      var scrollPos = (aEntry.scroll || "0,0").split(",");
-      scrollPos = [parseInt(scrollPos[0]) || 0, parseInt(scrollPos[1]) || 0];
-      shEntry.setScrollPosition(scrollPos[0], scrollPos[1]);
-    }
-
-    if (aEntry.postdata_b64) {
-      var postdata = atob(aEntry.postdata_b64);
-      var stream = Cc["@mozilla.org/io/string-input-stream;1"].
-                   createInstance(Ci.nsIStringInputStream);
-      stream.setData(postdata, postdata.length);
-      shEntry.postData = stream;
-    }
-
-    let childDocIdents = {};
-    if (aEntry.docIdentifier) {
-      // If we have a serialized document identifier, try to find an SHEntry
-      // which matches that doc identifier and adopt that SHEntry's
-      // BFCacheEntry.  If we don't find a match, insert shEntry as the match
-      // for the document identifier.
-      let matchingEntry = aDocIdentMap[aEntry.docIdentifier];
-      if (!matchingEntry) {
-        matchingEntry = {shEntry: shEntry, childDocIdents: childDocIdents};
-        aDocIdentMap[aEntry.docIdentifier] = matchingEntry;
-      }
-      else {
-        shEntry.adoptBFCacheEntry(matchingEntry.shEntry);
-        childDocIdents = matchingEntry.childDocIdents;
-      }
-    }
-
-    // The field aEntry.owner_b64 got renamed to aEntry.triggeringPricipal_b64 in
-    // Bug 1286472. To remain backward compatible we still have to support that
-    // field for a few cycles before we can remove it within Bug 1289785.
-     if (aEntry.owner_b64) {
-      aEntry.triggeringPrincipal_b64 = aEntry.owner_b64;
-      delete aEntry.owner_b64;
-    }
-
-    if (aEntry.triggeringPrincipal_b64) {
-      var triggeringPrincipalInput = Cc["@mozilla.org/io/string-input-stream;1"].
-                                     createInstance(Ci.nsIStringInputStream);
-      var binaryData = atob(aEntry.triggeringPrincipal_b64);
-      triggeringPrincipalInput.setData(binaryData, binaryData.length);
-      var binaryStream = Cc["@mozilla.org/binaryinputstream;1"].
-                         createInstance(Ci.nsIObjectInputStream);
-      binaryStream.setInputStream(triggeringPrincipalInput);
-      try { // Catch possible deserialization exceptions
-        shEntry.triggeringPrincipal = binaryStream.readObject(true);
-      } catch (ex) { debug(ex); }
-    }
-
-    if (aEntry.children && shEntry instanceof Ci.nsISHContainer) {
-      for (var i = 0; i < aEntry.children.length; i++) {
-        //XXXzpao Wallpaper patch for bug 514751
-        if (!aEntry.children[i].url)
-          continue;
-
-        // We're getting sessionrestore.js files with a cycle in the
-        // doc-identifier graph, likely due to bug 698656.  (That is, we have
-        // an entry where doc identifier A is an ancestor of doc identifier B,
-        // and another entry where doc identifier B is an ancestor of A.)
-        //
-        // If we were to respect these doc identifiers, we'd create a cycle in
-        // the SHEntries themselves, which causes the docshell to loop forever
-        // when it looks for the root SHEntry.
-        //
-        // So as a hack to fix this, we restrict the scope of a doc identifier
-        // to be a node's siblings and cousins, and pass childDocIdents, not
-        // aDocIdents, to _deserializeHistoryEntry.  That is, we say that two
-        // SHEntries with the same doc identifier have the same document iff
-        // they have the same parent or their parents have the same document.
-
-        shEntry.AddChild(this._deserializeHistoryEntry(aEntry.children[i], aIdMap,
-                                                       childDocIdents), i);
-      }
-    }
-
-    return shEntry;
-  },
-
-  /**
-   * Restore properties to a loaded document
-   */
-  restoreDocument: function ssi_restoreDocument(aWindow, aBrowser, aEvent) {
-    // wait for the top frame to be loaded completely
-    if (!aEvent || !aEvent.originalTarget || !aEvent.originalTarget.defaultView ||
-        aEvent.originalTarget.defaultView != aEvent.originalTarget.defaultView.top) {
-      return;
-    }
-
-    // always call this before injecting content into a document!
-    function hasExpectedURL(aDocument, aURL)
-      !aURL || aURL.replace(/#.*/, "") == aDocument.location.href.replace(/#.*/, "");
-
-    let selectedPageStyle = aBrowser.__SS_restore_pageStyle;
-    function restoreTextDataAndScrolling(aContent, aData, aPrefix) {
-      if (aData.formdata && hasExpectedURL(aContent.document, aData.url)) {
-        let formdata = aData.formdata;
-
-        // handle backwards compatibility
-        // this is a migration from pre-firefox 15. cf. bug 742051
-        if (!("xpath" in formdata || "id" in formdata)) {
-          formdata = { xpath: {}, id: {} };
-
-          for each (let [key, value] in Iterator(aData.formdata)) {
-            if (key.charAt(0) == "#") {
-              formdata.id[key.slice(1)] = value;
-            } else {
-              formdata.xpath[key] = value;
-            }
-          }
-        }
-
-        // for about:sessionrestore we saved the field as JSON to avoid
-        // nested instances causing humongous sessionstore.js files.
-        // cf. bug 467409
-        if (aData.url == "about:sessionrestore" &&
-            "sessionData" in formdata.id &&
-            typeof formdata.id["sessionData"] == "object") {
-          formdata.id["sessionData"] =
-            JSON.stringify(formdata.id["sessionData"]);
-        }
-
-        // update the formdata
-        aData.formdata = formdata;
-        // merge the formdata
-        DocumentUtils.mergeFormData(aContent.document, formdata);
-      }
-
-      if (aData.innerHTML) {
-        aWindow.setTimeout(function() {
-          if (aContent.document.designMode == "on" &&
-              hasExpectedURL(aContent.document, aData.url) &&
-              aContent.document.body) {
-            aContent.document.body.innerHTML = aData.innerHTML;
-          }
-        }, 0);
-      }
-      var match;
-      if (aData.scroll && (match = /(\d+),(\d+)/.exec(aData.scroll)) != null) {
-        aContent.scrollTo(match[1], match[2]);
-      }
-      Array.forEach(aContent.document.styleSheets, function(aSS) {
-        aSS.disabled = aSS.title && aSS.title != selectedPageStyle;
-      });
-      for (var i = 0; i < aContent.frames.length; i++) {
-        if (aData.children && aData.children[i] &&
-          hasExpectedURL(aContent.document, aData.url)) {
-          restoreTextDataAndScrolling(aContent.frames[i], aData.children[i], aPrefix + i + "|");
-        }
-      }
-    }
-
-    // don't restore text data and scrolling state if the user has navigated
-    // away before the loading completed (except for in-page navigation)
-    if (hasExpectedURL(aEvent.originalTarget, aBrowser.__SS_restore_data.url)) {
-      var content = aEvent.originalTarget.defaultView;
-      restoreTextDataAndScrolling(content, aBrowser.__SS_restore_data, "");
-      aBrowser.markupDocumentViewer.authorStyleDisabled = selectedPageStyle == "_nostyle";
-    }
-
-    // notify the tabbrowser that this document has been completely restored
-    this._sendTabRestoredNotification(aBrowser.__SS_restore_tab);
-
-    delete aBrowser.__SS_restore_data;
-    delete aBrowser.__SS_restore_pageStyle;
-    delete aBrowser.__SS_restore_tab;
-  },
-
-  /**
-   * Restore visibility and dimension features to a window
-   * @param aWindow
-   *        Window reference
-   * @param aWinData
-   *        Object containing session data for the window
-   */
-  restoreWindowFeatures: function ssi_restoreWindowFeatures(aWindow, aWinData) {
-    var hidden = (aWinData.hidden)?aWinData.hidden.split(","):[];
-    WINDOW_HIDEABLE_FEATURES.forEach(function(aItem) {
-      aWindow[aItem].visible = hidden.indexOf(aItem) == -1;
-    });
-
-    if (aWinData.isPopup) {
-      this._windows[aWindow.__SSi].isPopup = true;
-      if (aWindow.gURLBar) {
-        aWindow.gURLBar.readOnly = true;
-        aWindow.gURLBar.setAttribute("enablehistory", "false");
-      }
-    }
-    else {
-      delete this._windows[aWindow.__SSi].isPopup;
-      if (aWindow.gURLBar) {
-        aWindow.gURLBar.readOnly = false;
-        aWindow.gURLBar.setAttribute("enablehistory", "true");
-      }
-    }
-
-    var _this = this;
-    aWindow.setTimeout(function() {
-      _this.restoreDimensions.apply(_this, [aWindow,
-        +aWinData.width || 0,
-        +aWinData.height || 0,
-        "screenX" in aWinData ? +aWinData.screenX : NaN,
-        "screenY" in aWinData ? +aWinData.screenY : NaN,
-        aWinData.sizemode || "", aWinData.sidebar || ""]);
-    }, 0);
-  },
-
-  /**
-   * Restore a window's dimensions
-   * @param aWidth
-   *        Window width
-   * @param aHeight
-   *        Window height
-   * @param aLeft
-   *        Window left
-   * @param aTop
-   *        Window top
-   * @param aSizeMode
-   *        Window size mode (eg: maximized)
-   * @param aSidebar
-   *        Sidebar command
-   */
-  restoreDimensions: function ssi_restoreDimensions(aWindow, aWidth, aHeight, aLeft, aTop, aSizeMode, aSidebar) {
-    var win = aWindow;
-    var _this = this;
-    function win_(aName) { return _this._getWindowDimension(win, aName); }
-
-    // Find available space on the screen where this window is being placed
-    let screen = gScreenManager.screenForRect(aLeft, aTop, aWidth, aHeight);
-    if (screen && !this._prefBranch.getBoolPref("sessionstore.exactPos")) {
-      let screenLeft = {}, screenTop = {}, screenWidth = {}, screenHeight = {};
-      screen.GetAvailRectDisplayPix(screenLeft, screenTop, screenWidth, screenHeight);
-
-      // Screen X/Y are based on the origin of the screen's desktop-pixel coordinate space
-      let screenLeftCss = screenLeft.value;
-      let screenTopCss = screenTop.value;
-      
-      // Convert the screen's device pixel dimensions to CSS px dimensions
-      screen.GetAvailRect(screenLeft, screenTop, screenWidth, screenHeight);
-      let cssToDevScale = screen.defaultCSSScaleFactor;
-      let screenRightCss = screenLeftCss + screenWidth.value / cssToDevScale;
-      let screenBottomCss = screenTopCss + screenHeight.value / cssToDevScale;
-      
-      // Pull the window within the screen's bounds.
-      // First, ensure the left edge is on-screen
-      if (aLeft < screenLeftCss) {
-        aLeft = screenLeftCss;
-      }
-      // Then check the resulting right edge, and reduce it if necessary.
-      let right = aLeft + aWidth;
-      if (right > screenRightCss) {
-        right = screenRightCss;
-        // See if we can move the left edge leftwards to maintain width.
-        if (aLeft > screenLeftCss) {
-          aLeft = Math.max(right - aWidth, screenLeftCss);
-        }
-      }
-      // Finally, update aWidth to account for the adjusted left and right edges.
-      aWidth = right - aLeft;
-
-      // Do the same in the vertical dimension.
-      // First, ensure the top edge is on-screen
-      if (aTop < screenTopCss) {
-        aTop = screenTopCss;
-      }
-      // Then check the resulting right edge, and reduce it if necessary.
-      let bottom = aTop + aHeight;
-      if (bottom > screenBottomCss) {
-        bottom = screenBottomCss;
-        // See if we can move the top edge upwards to maintain height.
-        if (aTop > screenTopCss) {
-          aTop = Math.max(bottom - aHeight, screenTopCss);
-        }
-      }
-      // Finally, update aHeight to account for the adjusted top and bottom edges.
-      aHeight = bottom - aTop;
-    }
-
-    // Only modify those aspects which aren't correct yet
-    if (!isNaN(aLeft) && !isNaN(aTop) && (aLeft != win_("screenX") || aTop != win_("screenY"))) {
-      aWindow.moveTo(aLeft, aTop);
-    }
-    if (aWidth && aHeight && (aWidth != win_("width") || aHeight != win_("height"))) {
-      // Don't resize the window if it's currently maximized and we would
-      // maximize it again shortly after.
-      if (aSizeMode != "maximized" || win_("sizemode") != "maximized") {
-        aWindow.resizeTo(aWidth, aHeight);
-      }
-    }
-    
-    // Restore window state
-    if (aSizeMode && win_("sizemode") != aSizeMode)
-    {
-      switch (aSizeMode)
-      {
-      case "maximized":
-        aWindow.maximize();
-        break;
-      case "minimized":
-        aWindow.minimize();
-        break;
-      case "normal":
-        aWindow.restore();
-        break;
-      }
-    }
-    var sidebar = aWindow.document.getElementById("sidebar-box");
-    if (sidebar.getAttribute("sidebarcommand") != aSidebar) {
-      aWindow.toggleSidebar(aSidebar);
-    }
-    // since resizing/moving a window brings it to the foreground,
-    // we might want to re-focus the last focused window
-    if (this.windowToFocus) {
-      this.windowToFocus.focus();
-    }
-  },
-
-  /**
-   * Restores cookies
-   * @param aCookies
-   *        Array of cookie objects
-   */
-  restoreCookies: function ssi_restoreCookies(aCookies) {
-    // MAX_EXPIRY should be 2^63-1, but JavaScript can't handle that precision
-    var MAX_EXPIRY = Math.pow(2, 62);
-    for (let i = 0; i < aCookies.length; i++) {
-      var cookie = aCookies[i];
-      try {
-        Services.cookies.add(cookie.host, cookie.path || "", cookie.name || "",
-                             cookie.value, !!cookie.secure, !!cookie.httponly, true,
-                             "expiry" in cookie ? cookie.expiry : MAX_EXPIRY, {});
-      }
-      catch (ex) { Cu.reportError(ex); } // don't let a single cookie stop recovering
-    }
-  },
-
-  /* ........ Disk Access .............. */
-
-  /**
-   * save state delayed by N ms
-   * marks window as dirty (i.e. data update can't be skipped)
-   * @param aWindow
-   *        Window reference
-   * @param aDelay
-   *        Milliseconds to delay
-   */
-  saveStateDelayed: function ssi_saveStateDelayed(aWindow, aDelay) {
-    if (aWindow) {
-      this._dirtyWindows[aWindow.__SSi] = true;
-    }
-
-    if (!this._saveTimer) {
-      // interval until the next disk operation is allowed
-      var minimalDelay = this._lastSaveTime + this._interval - Date.now();
-
-      // if we have to wait, set a timer, otherwise saveState directly
-      aDelay = Math.max(minimalDelay, aDelay || 2000);
-      if (aDelay > 0) {
-        this._saveTimer = Cc["@mozilla.org/timer;1"].createInstance(Ci.nsITimer);
-        this._saveTimer.init(this, aDelay, Ci.nsITimer.TYPE_ONE_SHOT);
-      }
-      else {
-        this.saveState();
-      }
-    }
-  },
-
-  /**
-   * save state to disk
-   * @param aUpdateAll
-   *        Bool update all windows
-   */
-  saveState: function ssi_saveState(aUpdateAll) {
-    // If crash recovery is disabled, we only want to resume with pinned tabs
-    // if we crash.
-    let pinnedOnly = this._loadState == STATE_RUNNING && !this._resume_from_crash;
-
-    var oState = this._getCurrentState(aUpdateAll, pinnedOnly);
-    if (!oState) {
-      return;
-    }
-
-    // Forget about private windows.
-    for (let i = oState.windows.length - 1; i >= 0; i--) {
-      if (oState.windows[i].isPrivate) {
-        oState.windows.splice(i, 1);
-        if (oState.selectedWindow >= i) {
-          oState.selectedWindow--;
-        }
-      }
-    }
-
-    for (let i = oState._closedWindows.length - 1; i >= 0; i--) {
-      if (oState._closedWindows[i].isPrivate) {
-        oState._closedWindows.splice(i, 1);
-      }
-    }
-
-#ifndef XP_MACOSX
-    // We want to restore closed windows that are marked with _shouldRestore.
-    // We're doing this here because we want to control this only when saving
-    // the file.
-    while (oState._closedWindows.length) {
-      let i = oState._closedWindows.length - 1;
-      if (oState._closedWindows[i]._shouldRestore) {
-        delete oState._closedWindows[i]._shouldRestore;
-        oState.windows.unshift(oState._closedWindows.pop());
-      }
-      else {
-        // We only need to go until we hit !needsRestore since we're going in reverse
-        break;
-      }
-    }
-#endif
-
-    if (pinnedOnly) {
-      // Save original resume_session_once preference for when quiting browser,
-      // otherwise session will be restored next time browser starts and we
-      // only want it to be restored in the case of a crash.
-      if (this._resume_session_once_on_shutdown == null) {
-        this._resume_session_once_on_shutdown =
-          this._prefBranch.getBoolPref("sessionstore.resume_session_once");
-        this._prefBranch.setBoolPref("sessionstore.resume_session_once", true);
-        // flush the preference file so preference will be saved in case of a crash
-        Services.prefs.savePrefFile(null);
-      }
-    }
-
-    // Persist the last session if we deferred restoring it
-    if (this._lastSessionState)
-      oState.lastSessionState = this._lastSessionState;
-
-    // Make sure that we keep the previous session if we started with a single
-    // private window and no non-private windows have been opened, yet.
-    if (this._deferredInitialState) {
-      oState.windows = this._deferredInitialState.windows || [];
-    }
-
-    this._saveStateObject(oState);
-  },
-
-  /**
-   * write a state object to disk
-   */
-  _saveStateObject: function ssi_saveStateObject(aStateObj) {
-    let data = this._toJSONString(aStateObj);
-
-    let stateString = this._createSupportsString(data);
-    Services.obs.notifyObservers(stateString, "sessionstore-state-write", "");
-    data = stateString.data;
-
-    // Don't touch the file if an observer has deleted all state data.
-    if (!data) {
-      return;
-    }
-
-    let promise;
-    // If "sessionstore.resume_from_crash" is true, attempt to backup the
-    // session file first, before writing to it.
-    if (this._resume_from_crash) {
-      // Note that we do not have race conditions here as _SessionFile
-      // guarantees that any I/O operation is completed before proceeding to
-      // the next I/O operation.
-      // Note backup happens only once, on initial save.
-      promise = this._backupSessionFileOnce;
-    } else {
-      promise = Promise.resolve();
-    }
-
-    // Attempt to write to the session file (potentially, depending on
-    // "sessionstore.resume_from_crash" preference, after successful backup).
-    promise = promise.then(function onSuccess() {
-      // Write (atomically) to a session file, using a tmp file.
-      return _SessionFile.write(data);
-    });
-
-    // Once the session file is successfully updated, save the time stamp of the
-    // last save and notify the observers.
-    promise = promise.then(() => {
-      this._lastSaveTime = Date.now();
-      Services.obs.notifyObservers(null, "sessionstore-state-write-complete",
-        "");
-    });
-  },
-
-  /* ........ Auxiliary Functions .............. */
-
-  // Wrap a string as a nsISupports
-  _createSupportsString: function ssi_createSupportsString(aData) {
-    let string = Cc["@mozilla.org/supports-string;1"]
-                   .createInstance(Ci.nsISupportsString);
-    string.data = aData;
-    return string;
-  },
-
-  /**
-   * call a callback for all currently opened browser windows
-   * (might miss the most recent one)
-   * @param aFunc
-   *        Callback each window is passed to
-   */
-  _forEachBrowserWindow: function ssi_forEachBrowserWindow(aFunc) {
-    var windowsEnum = Services.wm.getEnumerator("navigator:browser");
-
-    while (windowsEnum.hasMoreElements()) {
-      var window = windowsEnum.getNext();
-      if (window.__SSi && !window.closed) {
-        aFunc.call(this, window);
-      }
-    }
-  },
-
-  /**
-   * Returns most recent window
-   * @returns Window reference
-   */
-  _getMostRecentBrowserWindow: function ssi_getMostRecentBrowserWindow() {
-    var win = Services.wm.getMostRecentWindow("navigator:browser");
-    if (!win)
-      return null;
-    if (!win.closed)
-      return win;
-
-#ifdef BROKEN_WM_Z_ORDER
-    win = null;
-    var windowsEnum = Services.wm.getEnumerator("navigator:browser");
-    // this is oldest to newest, so this gets a bit ugly
-    while (windowsEnum.hasMoreElements()) {
-      let nextWin = windowsEnum.getNext();
-      if (!nextWin.closed)
-        win = nextWin;
-    }
-    return win;
-#else
-    var windowsEnum =
-      Services.wm.getZOrderDOMWindowEnumerator("navigator:browser", true);
-    while (windowsEnum.hasMoreElements()) {
-      win = windowsEnum.getNext();
-      if (!win.closed)
-        return win;
-    }
-    return null;
-#endif
-  },
-
-  /**
-   * Calls onClose for windows that are determined to be closed but aren't
-   * destroyed yet, which would otherwise cause getBrowserState and
-   * setBrowserState to treat them as open windows.
-   */
-  _handleClosedWindows: function ssi_handleClosedWindows() {
-    var windowsEnum = Services.wm.getEnumerator("navigator:browser");
-
-    while (windowsEnum.hasMoreElements()) {
-      var window = windowsEnum.getNext();
-      if (window.closed) {
-        this.onClose(window);
-      }
-    }
-  },
-
-  /**
-   * open a new browser window for a given session state
-   * called when restoring a multi-window session
-   * @param aState
-   *        Object containing session data
-   */
-  _openWindowWithState: function ssi_openWindowWithState(aState) {
-    var argString = Cc["@mozilla.org/supports-string;1"].
-                    createInstance(Ci.nsISupportsString);
-    argString.data = "";
-
-    // Build feature string
-    let features = "chrome,dialog=no,macsuppressanimation,all";
-    let winState = aState.windows[0];
-    WINDOW_ATTRIBUTES.forEach(function(aFeature) {
-      // Use !isNaN as an easy way to ignore sizemode and check for numbers
-      if (aFeature in winState && !isNaN(winState[aFeature]))
-        features += "," + aFeature + "=" + winState[aFeature];
-    });
-
-    if (winState.isPrivate) {
-      features += ",private";
-    }
-
-    var window =
-      Services.ww.openWindow(null, this._prefBranch.getCharPref("chromeURL"),
-                             "_blank", features, argString);
-
-    do {
-      var ID = "window" + Math.random();
-    } while (ID in this._statesToRestore);
-    this._statesToRestore[(window.__SS_restoreID = ID)] = aState;
-
-    return window;
-  },
-
-  /**
-   * Whether or not to resume session, if not recovering from a crash.
-   * @returns bool
-   */
-  _doResumeSession: function ssi_doResumeSession() {
-    return this._prefBranch.getIntPref("startup.page") == 3 ||
-           this._prefBranch.getBoolPref("sessionstore.resume_session_once");
-  },
-
-  /**
-   * whether the user wants to load any other page at startup
-   * (except the homepage) - needed for determining whether to overwrite the current tabs
-   * C.f.: nsBrowserContentHandler's defaultArgs implementation.
-   * @returns bool
-   */
-  _isCmdLineEmpty: function ssi_isCmdLineEmpty(aWindow, aState) {
-    var pinnedOnly = aState.windows &&
-                     aState.windows.every(function (win)
-                       win.tabs.every(function (tab) tab.pinned));
-
-    let hasFirstArgument = aWindow.arguments && aWindow.arguments[0];
-    if (!pinnedOnly) {
-      let defaultArgs = Cc["@mozilla.org/browser/clh;1"].
-                        getService(Ci.nsIBrowserHandler).defaultArgs;
-      if (aWindow.arguments &&
-          aWindow.arguments[0] &&
-          aWindow.arguments[0] == defaultArgs)
-        hasFirstArgument = false;
-    }
-
-    return !hasFirstArgument;
-  },
-
-  /**
-   * don't save sensitive data if the user doesn't want to
-   * (distinguishes between encrypted and non-encrypted sites)
-   * @param aIsHTTPS
-   *        Bool is encrypted
-   * @param aUseDefaultPref
-   *        don't do normal check for deferred
-   * @returns bool
-   */
-  checkPrivacyLevel: function ssi_checkPrivacyLevel(aIsHTTPS, aUseDefaultPref) {
-    let pref = "sessionstore.privacy_level";
-    // If we're in the process of quitting and we're not autoresuming the session
-    // then we should treat it as a deferred session. We have a different privacy
-    // pref for that case.
-    if (!aUseDefaultPref && this._loadState == STATE_QUITTING && !this._doResumeSession())
-      pref = "sessionstore.privacy_level_deferred";
-    return this._prefBranch.getIntPref(pref) < (aIsHTTPS ? PRIVACY_ENCRYPTED : PRIVACY_FULL);
-  },
-
-  /**
-   * on popup windows, the XULWindow's attributes seem not to be set correctly
-   * we use thus JSDOMWindow attributes for sizemode and normal window attributes
-   * (and hope for reasonable values when maximized/minimized - since then
-   * outerWidth/outerHeight aren't the dimensions of the restored window)
-   * @param aWindow
-   *        Window reference
-   * @param aAttribute
-   *        String sizemode | width | height | other window attribute
-   * @returns string
-   */
-  _getWindowDimension: function ssi_getWindowDimension(aWindow, aAttribute) {
-    if (aAttribute == "sizemode") {
-      switch (aWindow.windowState) {
-      case aWindow.STATE_FULLSCREEN:
-      case aWindow.STATE_MAXIMIZED:
-        return "maximized";
-      case aWindow.STATE_MINIMIZED:
-        return "minimized";
-      default:
-        return "normal";
-      }
-    }
-
-    var dimension;
-    switch (aAttribute) {
-    case "width":
-      dimension = aWindow.outerWidth;
-      break;
-    case "height":
-      dimension = aWindow.outerHeight;
-      break;
-    default:
-      dimension = aAttribute in aWindow ? aWindow[aAttribute] : "";
-      break;
-    }
-
-    if (aWindow.windowState == aWindow.STATE_NORMAL) {
-      return dimension;
-    }
-    return aWindow.document.documentElement.getAttribute(aAttribute) || dimension;
-  },
-
-  /**
-   * Get nsIURI from string
-   * @param string
-   * @returns nsIURI
-   */
-  _getURIFromString: function ssi_getURIFromString(aString) {
-    return Services.io.newURI(aString, null, null);
-  },
-
-  /**
-   * @param aState is a session state
-   * @param aRecentCrashes is the number of consecutive crashes
-   * @returns whether a restore page will be needed for the session state
-   */
-  _needsRestorePage: function ssi_needsRestorePage(aState, aRecentCrashes) {
-    const SIX_HOURS_IN_MS = 6 * 60 * 60 * 1000;
-
-    // don't display the page when there's nothing to restore
-    let winData = aState.windows || null;
-    if (!winData || winData.length == 0)
-      return false;
-
-    // don't wrap a single about:sessionrestore page
-    if (winData.length == 1 && winData[0].tabs &&
-        winData[0].tabs.length == 1 && winData[0].tabs[0].entries &&
-        winData[0].tabs[0].entries.length == 1 &&
-        winData[0].tabs[0].entries[0].url == "about:sessionrestore")
-      return false;
-
-    // don't automatically restore in Safe Mode
-    if (Services.appinfo.inSafeMode)
-      return true;
-
-    let max_resumed_crashes =
-      this._prefBranch.getIntPref("sessionstore.max_resumed_crashes");
-    let sessionAge = aState.session && aState.session.lastUpdate &&
-                     (Date.now() - aState.session.lastUpdate);
-
-    return max_resumed_crashes != -1 &&
-           (aRecentCrashes > max_resumed_crashes ||
-            sessionAge && sessionAge >= SIX_HOURS_IN_MS);
-  },
-
-  /**
-   * Determine if the tab state we're passed is something we should save. This
-   * is used when closing a tab or closing a window with a single tab
-   *
-   * @param aTabState
-   *        The current tab state
-   * @returns boolean
-   */
-  _shouldSaveTabState: function ssi_shouldSaveTabState(aTabState) {
-    // If the tab has only a transient about: history entry, no other
-    // session history, and no userTypedValue, then we don't actually want to
-    // store this tab's data.
-    return aTabState.entries.length &&
-           !(aTabState.entries.length == 1 &&
-                (aTabState.entries[0].url == "about:blank" ||
-                 aTabState.entries[0].url == "about:newtab") &&
-                 !aTabState.userTypedValue);
-  },
-
-  /**
-   * Determine if we can restore history into this tab.
-   * This will be false when a tab has been removed (usually between
-   * restoreHistoryPrecursor && restoreHistory) or if the tab is still marked
-   * as loading.
-   *
-   * @param aTab
-   * @returns boolean
-   */
-  _canRestoreTabHistory: function ssi_canRestoreTabHistory(aTab) {
-    return aTab.parentNode && aTab.linkedBrowser &&
-           aTab.linkedBrowser.__SS_tabStillLoading;
-  },
-
-  /**
-   * This is going to take a state as provided at startup (via
-   * nsISessionStartup.state) and split it into 2 parts. The first part
-   * (defaultState) will be a state that should still be restored at startup,
-   * while the second part (state) is a state that should be saved for later.
-   * defaultState will be comprised of windows with only pinned tabs, extracted
-   * from state. It will contain the cookies that go along with the history
-   * entries in those tabs. It will also contain window position information.
-   *
-   * defaultState will be restored at startup. state will be placed into
-   * this._lastSessionState and will be kept in case the user explicitly wants
-   * to restore the previous session (publicly exposed as restoreLastSession).
-   *
-   * @param state
-   *        The state, presumably from nsISessionStartup.state
-   * @returns [defaultState, state]
-   */
-  _prepDataForDeferredRestore: function ssi_prepDataForDeferredRestore(state) {
-    // Make sure that we don't modify the global state as provided by
-    // nsSessionStartup.state. Converting the object to a JSON string and
-    // parsing it again is the easiest way to do that, although not the most
-    // efficient one. Deferred sessions that don't have automatic session
-    // restore enabled tend to be a lot smaller though so that this shouldn't
-    // be a big perf hit.
-    state = JSON.parse(JSON.stringify(state));
-
-    let defaultState = { windows: [], selectedWindow: 1 };
-
-    state.selectedWindow = state.selectedWindow || 1;
-
-    // Look at each window, remove pinned tabs, adjust selectedindex,
-    // remove window if necessary.
-    for (let wIndex = 0; wIndex < state.windows.length;) {
-      let window = state.windows[wIndex];
-      window.selected = window.selected || 1;
-      // We're going to put the state of the window into this object
-      let pinnedWindowState = { tabs: [], cookies: []};
-      for (let tIndex = 0; tIndex < window.tabs.length;) {
-        if (window.tabs[tIndex].pinned) {
-          // Adjust window.selected
-          if (tIndex + 1 < window.selected)
-            window.selected -= 1;
-          else if (tIndex + 1 == window.selected)
-            pinnedWindowState.selected = pinnedWindowState.tabs.length + 2;
-            // + 2 because the tab isn't actually in the array yet
-
-          // Now add the pinned tab to our window
-          pinnedWindowState.tabs =
-            pinnedWindowState.tabs.concat(window.tabs.splice(tIndex, 1));
-          // We don't want to increment tIndex here.
-          continue;
-        }
-        tIndex++;
-      }
-
-      // At this point the window in the state object has been modified (or not)
-      // We want to build the rest of this new window object if we have pinnedTabs.
-      if (pinnedWindowState.tabs.length) {
-        // First get the other attributes off the window
-        WINDOW_ATTRIBUTES.forEach(function(attr) {
-          if (attr in window) {
-            pinnedWindowState[attr] = window[attr];
-            delete window[attr];
-          }
-        });
-        // We're just copying position data into the pinned window.
-        // Not copying over:
-        // - _closedTabs
-        // - extData
-        // - isPopup
-        // - hidden
-
-        // Assign a unique ID to correlate the window to be opened with the
-        // remaining data
-        window.__lastSessionWindowID = pinnedWindowState.__lastSessionWindowID
-                                     = "" + Date.now() + Math.random();
-
-        // Extract the cookies that belong with each pinned tab
-        this._splitCookiesFromWindow(window, pinnedWindowState);
-
-        // Actually add this window to our defaultState
-        defaultState.windows.push(pinnedWindowState);
-        // Remove the window from the state if it doesn't have any tabs
-        if (!window.tabs.length) {
-          if (wIndex + 1 <= state.selectedWindow)
-            state.selectedWindow -= 1;
-          else if (wIndex + 1 == state.selectedWindow)
-            defaultState.selectedIndex = defaultState.windows.length + 1;
-
-          state.windows.splice(wIndex, 1);
-          // We don't want to increment wIndex here.
-          continue;
-        }
-
-
-      }
-      wIndex++;
-    }
-
-    return [defaultState, state];
-  },
-
-  /**
-   * Splits out the cookies from aWinState into aTargetWinState based on the
-   * tabs that are in aTargetWinState.
-   * This alters the state of aWinState and aTargetWinState.
-   */
-  _splitCookiesFromWindow:
-    function ssi_splitCookiesFromWindow(aWinState, aTargetWinState) {
-    if (!aWinState.cookies || !aWinState.cookies.length)
-      return;
-
-    // Get the hosts for history entries in aTargetWinState
-    let cookieHosts = {};
-    aTargetWinState.tabs.forEach(function(tab) {
-      tab.entries.forEach(function(entry) {
-        this._extractHostsForCookiesFromEntry(entry, cookieHosts, false);
-      }, this);
-    }, this);
-
-    // By creating a regex we reduce overhead and there is only one loop pass
-    // through either array (cookieHosts and aWinState.cookies).
-    let hosts = Object.keys(cookieHosts).join("|").replace("\\.", "\\.", "g");
-    // If we don't actually have any hosts, then we don't want to do anything.
-    if (!hosts.length)
-      return;
-    let cookieRegex = new RegExp(".*(" + hosts + ")");
-    for (let cIndex = 0; cIndex < aWinState.cookies.length;) {
-      if (cookieRegex.test(aWinState.cookies[cIndex].host)) {
-        aTargetWinState.cookies =
-          aTargetWinState.cookies.concat(aWinState.cookies.splice(cIndex, 1));
-        continue;
-      }
-      cIndex++;
-    }
-  },
-
-  /**
-   * Converts a JavaScript object into a JSON string
-   * (see http://www.json.org/ for more information).
-   *
-   * The inverse operation consists of JSON.parse(JSON_string).
-   *
-   * @param aJSObject is the object to be converted
-   * @returns the object's JSON representation
-   */
-  _toJSONString: function ssi_toJSONString(aJSObject) {
-    return JSON.stringify(aJSObject);
-  },
-
-  _sendRestoreCompletedNotifications: function ssi_sendRestoreCompletedNotifications() {
-    // not all windows restored, yet
-    if (this._restoreCount > 1) {
-      this._restoreCount--;
-      return;
-    }
-
-    // observers were already notified
-    if (this._restoreCount == -1)
-      return;
-
-    // This was the last window restored at startup, notify observers.
-    Services.obs.notifyObservers(null,
-      this._browserSetState ? NOTIFY_BROWSER_STATE_RESTORED : NOTIFY_WINDOWS_RESTORED,
-      "");
-
-    this._browserSetState = false;
-    this._restoreCount = -1;
-  },
-
-   /**
-   * Set the given window's busy state
-   * @param aWindow the window
-   * @param aValue the window's busy state
-   */
-  _setWindowStateBusyValue:
-    function ssi_changeWindowStateBusyValue(aWindow, aValue) {
-
-    this._windows[aWindow.__SSi].busy = aValue;
-
-    // Keep the to-be-restored state in sync because that is returned by
-    // getWindowState() as long as the window isn't loaded, yet.
-    if (!this._isWindowLoaded(aWindow)) {
-      let stateToRestore = this._statesToRestore[aWindow.__SS_restoreID].windows[0];
-      stateToRestore.busy = aValue;
-    }
-  },
-
-  /**
-   * Set the given window's state to 'not busy'.
-   * @param aWindow the window
-   */
-  _setWindowStateReady: function ssi_setWindowStateReady(aWindow) {
-    this._setWindowStateBusyValue(aWindow, false);
-    this._sendWindowStateEvent(aWindow, "Ready");
-  },
-
-  /**
-   * Set the given window's state to 'busy'.
-   * @param aWindow the window
-   */
-  _setWindowStateBusy: function ssi_setWindowStateBusy(aWindow) {
-    this._setWindowStateBusyValue(aWindow, true);
-    this._sendWindowStateEvent(aWindow, "Busy");
-  },
-
-  /**
-   * Dispatch an SSWindowState_____ event for the given window.
-   * @param aWindow the window
-   * @param aType the type of event, SSWindowState will be prepended to this string
-   */
-  _sendWindowStateEvent: function ssi_sendWindowStateEvent(aWindow, aType) {
-    let event = aWindow.document.createEvent("Events");
-    event.initEvent("SSWindowState" + aType, true, false);
-    aWindow.dispatchEvent(event);
-  },
-
-  /**
-   * Dispatch the SSTabRestored event for the given tab.
-   * @param aTab the which has been restored
-   */
-  _sendTabRestoredNotification: function ssi_sendTabRestoredNotification(aTab) {
-      let event = aTab.ownerDocument.createEvent("Events");
-      event.initEvent("SSTabRestored", true, false);
-      aTab.dispatchEvent(event);
-  },
-
-  /**
-   * @param aWindow
-   *        Window reference
-   * @returns whether this window's data is still cached in _statesToRestore
-   *          because it's not fully loaded yet
-   */
-  _isWindowLoaded: function ssi_isWindowLoaded(aWindow) {
-    return !aWindow.__SS_restoreID;
-  },
-
-  /**
-   * Replace "Loading..." with the tab label (with minimal side-effects)
-   * @param aString is the string the title is stored in
-   * @param aTabbrowser is a tabbrowser object, containing aTab
-   * @param aTab is the tab whose title we're updating & using
-   *
-   * @returns aString that has been updated with the new title
-   */
-  _replaceLoadingTitle : function ssi_replaceLoadingTitle(aString, aTabbrowser, aTab) {
-    if (aString == aTabbrowser.mStringBundle.getString("tabs.connecting")) {
-      aTabbrowser.setTabTitle(aTab);
-      [aString, aTab.label] = [aTab.label, aString];
-    }
-    return aString;
-  },
-
-  /**
-   * Resize this._closedWindows to the value of the pref, except in the case
-   * where we don't have any non-popup windows on Windows and Linux. Then we must
-   * resize such that we have at least one non-popup window.
-   */
-  _capClosedWindows : function ssi_capClosedWindows() {
-    if (this._closedWindows.length <= this._max_windows_undo)
-      return;
-    let spliceTo = this._max_windows_undo;
-#ifndef XP_MACOSX
-    let normalWindowIndex = 0;
-    // try to find a non-popup window in this._closedWindows
-    while (normalWindowIndex < this._closedWindows.length &&
-           !!this._closedWindows[normalWindowIndex].isPopup)
-      normalWindowIndex++;
-    if (normalWindowIndex >= this._max_windows_undo)
-      spliceTo = normalWindowIndex + 1;
-#endif
-    this._closedWindows.splice(spliceTo, this._closedWindows.length);
-  },
-
-  _clearRestoringWindows: function ssi_clearRestoringWindows() {
-    for (let i = 0; i < this._closedWindows.length; i++) {
-      delete this._closedWindows[i]._shouldRestore;
-    }
-  },
-
-  /**
-   * Reset state to prepare for a new session state to be restored.
-   */
-  _resetRestoringState: function ssi_initRestoringState() {
-    TabRestoreQueue.reset();
-    this._tabsRestoringCount = 0;
-  },
-
-  /**
-   * Reset the restoring state for a particular tab. This will be called when
-   * removing a tab or when a tab needs to be reset (it's being overwritten).
-   *
-   * @param aTab
-   *        The tab that will be "reset"
-   */
-  _resetTabRestoringState: function ssi_resetTabRestoringState(aTab) {
-    let window = aTab.ownerDocument.defaultView;
-    let browser = aTab.linkedBrowser;
-
-    // Keep the tab's previous state for later in this method
-    let previousState = browser.__SS_restoreState;
-
-    // The browser is no longer in any sort of restoring state.
-    delete browser.__SS_restoreState;
-
-    aTab.removeAttribute("pending");
-    browser.removeAttribute("pending");
-
-    // We want to decrement window.__SS_tabsToRestore here so that we always
-    // decrement it AFTER a tab is done restoring or when a tab gets "reset".
-    window.__SS_tabsToRestore--;
-
-    // Remove the progress listener if we should.
-    this._removeTabsProgressListener(window);
-
-    if (previousState == TAB_STATE_RESTORING) {
-      if (this._tabsRestoringCount)
-        this._tabsRestoringCount--;
-    }
-    else if (previousState == TAB_STATE_NEEDS_RESTORE) {
-      // Make sure the session history listener is removed. This is normally
-      // done in restoreTab, but this tab is being removed before that gets called.
-      this._removeSHistoryListener(aTab);
-
-      // Make sure that the tab is removed from the list of tabs to restore.
-      // Again, this is normally done in restoreTab, but that isn't being called
-      // for this tab.
-      TabRestoreQueue.remove(aTab);
-    }
-  },
-
-  /**
-   * Add the tabs progress listener to the window if it isn't already
-   *
-   * @param aWindow
-   *        The window to add our progress listener to
-   */
-  _ensureTabsProgressListener: function ssi_ensureTabsProgressListener(aWindow) {
-    let tabbrowser = aWindow.gBrowser;
-    if (tabbrowser.mTabsProgressListeners.indexOf(gRestoreTabsProgressListener) == -1)
-      tabbrowser.addTabsProgressListener(gRestoreTabsProgressListener);
-  },
-
-  /**
-   * Attempt to remove the tabs progress listener from the window.
-   *
-   * @param aWindow
-   *        The window from which to remove our progress listener from
-   */
-  _removeTabsProgressListener: function ssi_removeTabsProgressListener(aWindow) {
-    // If there are no tabs left to restore (or restoring) in this window, then
-    // we can safely remove the progress listener from this window.
-    if (!aWindow.__SS_tabsToRestore)
-      aWindow.gBrowser.removeTabsProgressListener(gRestoreTabsProgressListener);
-  },
-
-  /**
-   * Remove the session history listener from the tab's browser if there is one.
-   *
-   * @param aTab
-   *        The tab who's browser to remove the listener
-   */
-  _removeSHistoryListener: function ssi_removeSHistoryListener(aTab) {
-    let browser = aTab.linkedBrowser;
-    if (browser.__SS_shistoryListener) {
-      browser.webNavigation.sessionHistory.
-                            removeSHistoryListener(browser.__SS_shistoryListener);
-      delete browser.__SS_shistoryListener;
-    }
-  }
-};
-
-/**
- * Priority queue that keeps track of a list of tabs to restore and returns
- * the tab we should restore next, based on priority rules. We decide between
- * pinned, visible and hidden tabs in that and FIFO order. Hidden tabs are only
- * restored with restore_hidden_tabs=true.
- */
-var TabRestoreQueue = {
-  // The separate buckets used to store tabs.
-  tabs: {priority: [], visible: [], hidden: []},
-
-  // Preferences used by the TabRestoreQueue to determine which tabs
-  // are restored automatically and which tabs will be on-demand.
-  prefs: {
-    // Lazy getter that returns whether tabs are restored on demand.
-    get restoreOnDemand() {
-      let updateValue = () => {
-        let value = Services.prefs.getBoolPref(PREF);
-        let definition = {value: value, configurable: true};
-        Object.defineProperty(this, "restoreOnDemand", definition);
-        return value;
-      }
-
-      const PREF = "browser.sessionstore.restore_on_demand";
-      Services.prefs.addObserver(PREF, updateValue, false);
-      return updateValue();
-    },
-
-    // Lazy getter that returns whether pinned tabs are restored on demand.
-    get restorePinnedTabsOnDemand() {
-      let updateValue = () => {
-        let value = Services.prefs.getBoolPref(PREF);
-        let definition = {value: value, configurable: true};
-        Object.defineProperty(this, "restorePinnedTabsOnDemand", definition);
-        return value;
-      }
-
-      const PREF = "browser.sessionstore.restore_pinned_tabs_on_demand";
-      Services.prefs.addObserver(PREF, updateValue, false);
-      return updateValue();
-    },
-
-    // Lazy getter that returns whether we should restore hidden tabs.
-    get restoreHiddenTabs() {
-      let updateValue = () => {
-        let value = Services.prefs.getBoolPref(PREF);
-        let definition = {value: value, configurable: true};
-        Object.defineProperty(this, "restoreHiddenTabs", definition);
-        return value;
-      }
-
-      const PREF = "browser.sessionstore.restore_hidden_tabs";
-      Services.prefs.addObserver(PREF, updateValue, false);
-      return updateValue();
-    }
-  },
-
-  // Resets the queue and removes all tabs.
-  reset: function () {
-    this.tabs = {priority: [], visible: [], hidden: []};
-  },
-
-  // Adds a tab to the queue and determines its priority bucket.
-  add: function (tab) {
-    let {priority, hidden, visible} = this.tabs;
-
-    if (tab.pinned) {
-      priority.push(tab);
-    } else if (tab.hidden) {
-      hidden.push(tab);
-    } else {
-      visible.push(tab);
-    }
-  },
-
-  // Removes a given tab from the queue, if it's in there.
-  remove: function (tab) {
-    let {priority, hidden, visible} = this.tabs;
-
-    // We'll always check priority first since we don't
-    // have an indicator if a tab will be there or not.
-    let set = priority;
-    let index = set.indexOf(tab);
-
-    if (index == -1) {
-      set = tab.hidden ? hidden : visible;
-      index = set.indexOf(tab);
-    }
-
-    if (index > -1) {
-      set.splice(index, 1);
-    }
-  },
-
-  // Returns and removes the tab with the highest priority.
-  shift: function () {
-    let set;
-    let {priority, hidden, visible} = this.tabs;
-
-    let {restoreOnDemand, restorePinnedTabsOnDemand} = this.prefs;
-    let restorePinned = !(restoreOnDemand && restorePinnedTabsOnDemand);
-    if (restorePinned && priority.length) {
-      set = priority;
-    } else if (!restoreOnDemand) {
-      if (visible.length) {
-        set = visible;
-      } else if (this.prefs.restoreHiddenTabs && hidden.length) {
-        set = hidden;
-      }
-    }
-
-    return set && set.shift();
-  },
-
-  // Moves a given tab from the 'hidden' to the 'visible' bucket.
-  hiddenToVisible: function (tab) {
-    let {hidden, visible} = this.tabs;
-    let index = hidden.indexOf(tab);
-
-    if (index > -1) {
-      hidden.splice(index, 1);
-      visible.push(tab);
-    } else {
-      throw new Error("restore queue: hidden tab not found");
-    }
-  },
-
-  // Moves a given tab from the 'visible' to the 'hidden' bucket.
-  visibleToHidden: function (tab) {
-    let {visible, hidden} = this.tabs;
-    let index = visible.indexOf(tab);
-
-    if (index > -1) {
-      visible.splice(index, 1);
-      hidden.push(tab);
-    } else {
-      throw new Error("restore queue: visible tab not found");
-    }
-  }
-};
-
-// A map storing a closed window's state data until it goes aways (is GC'ed).
-// This ensures that API clients can still read (but not write) states of
-// windows they still hold a reference to but we don't.
-var DyingWindowCache = {
-  _data: new WeakMap(),
-
-  has: function (window) {
-    return this._data.has(window);
-  },
-
-  get: function (window) {
-    return this._data.get(window);
-  },
-
-  set: function (window, data) {
-    this._data.set(window, data);
-  },
-
-  remove: function (window) {
-    this._data.delete(window);
-  }
-};
-
-// A set of tab attributes to persist. We will read a given list of tab
-// attributes when collecting tab data and will re-set those attributes when
-// the given tab data is restored to a new tab.
-var TabAttributes = {
-  _attrs: new Set(),
-
-  // We never want to directly read or write those attributes.
-  // 'image' should not be accessed directly but handled by using the
-  //         gBrowser.getIcon()/setIcon() methods.
-  // 'pending' is used internal by sessionstore and managed accordingly.
-  // 'skipbackgroundnotify' is used internal by tabbrowser.xml.
-  _skipAttrs: new Set(["image", "pending", "skipbackgroundnotify"]),
-
-  persist: function (name) {
-    if (this._attrs.has(name) || this._skipAttrs.has(name)) {
-      return false;
-    }
-
-    this._attrs.add(name);
-    return true;
-  },
-
-  get: function (tab) {
-    let data = {};
-
-    for (let name of this._attrs) {
-      if (tab.hasAttribute(name)) {
-        data[name] = tab.getAttribute(name);
-      }
-    }
-
-    return data;
-  },
-
-  set: function (tab, data = {}) {
-    // Clear attributes.
-    for (let name of this._attrs) {
-      tab.removeAttribute(name);
-    }
-
-    // Set attributes.
-    for (let name in data) {
-      tab.setAttribute(name, data[name]);
-    }
-  }
-};
-
-// This is used to help meter the number of restoring tabs. This is the control
-// point for telling the next tab to restore. It gets attached to each gBrowser
-// via gBrowser.addTabsProgressListener
-var gRestoreTabsProgressListener = {
-  onStateChange: function(aBrowser, aWebProgress, aRequest, aStateFlags, aStatus) {
-    // Ignore state changes on browsers that we've already restored and state
-    // changes that aren't applicable.
-    if (aBrowser.__SS_restoreState &&
-        aBrowser.__SS_restoreState == TAB_STATE_RESTORING &&
-        aStateFlags & Ci.nsIWebProgressListener.STATE_STOP &&
-        aStateFlags & Ci.nsIWebProgressListener.STATE_IS_NETWORK &&
-        aStateFlags & Ci.nsIWebProgressListener.STATE_IS_WINDOW) {
-      // We need to reset the tab before starting the next restore.
-      let win = aBrowser.ownerDocument.defaultView;
-      let tab = win.gBrowser.getTabForBrowser(aBrowser);
-      SessionStoreInternal._resetTabRestoringState(tab);
-      SessionStoreInternal.restoreNextTab();
-    }
-  }
-};
-
-// A SessionStoreSHistoryListener will be attached to each browser before it is
-// restored. We need to catch reloads that occur before the tab is restored
-// because otherwise, docShell will reload an old URI (usually about:blank).
-function SessionStoreSHistoryListener(aTab) {
-  this.tab = aTab;
-}
-SessionStoreSHistoryListener.prototype = {
-  QueryInterface: XPCOMUtils.generateQI([
-    Ci.nsISHistoryListener,
-    Ci.nsISupportsWeakReference
-  ]),
-  browser: null,
-  OnHistoryNewEntry: function(aNewURI) { },
-  OnHistoryGoBack: function(aBackURI) { return true; },
-  OnHistoryGoForward: function(aForwardURI) { return true; },
-  OnHistoryGotoIndex: function(aIndex, aGotoURI) { return true; },
-  OnHistoryPurge: function(aNumEntries) { return true; },
-  OnHistoryReload: function(aReloadURI, aReloadFlags) {
-    // On reload, we want to make sure that session history loads the right
-    // URI. In order to do that, we will juet call restoreTab. That will remove
-    // the history listener and load the right URI.
-    SessionStoreInternal.restoreTab(this.tab);
-    // Returning false will stop the load that docshell is attempting.
-    return false;
-  }
-}
-
-// See toolkit/forgetaboutsite/ForgetAboutSite.jsm
-String.prototype.hasRootDomain = function hasRootDomain(aDomain) {
-  let index = this.indexOf(aDomain);
-  if (index == -1)
-    return false;
-
-  if (this == aDomain)
-    return true;
-
-  let prevChar = this[index - 1];
-  return (index == (this.length - aDomain.length)) &&
-         (prevChar == "." || prevChar == "/");
-}