The Tor Browser: browser/metro/base/content/browser.js@6474c204b198 (annotated)

browser/metro/base/content/browser.js@6474c204b198 (annotated)

browser/metro/base/content/browser.js

Wed, 31 Dec 2014 06:09:35 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:09:35 +0100
changeset 0: 6474c204b198
permissions: -rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

 // -*- Mode: js2; tab-width: 2; indent-tabs-mode: nil; js2-basic-offset: 2; js2-skip-preprocessor-directives: t; -*-
 /* 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/. */
 let Cc = Components.classes;
 let Ci = Components.interfaces;
 let Cu = Components.utils;
 let Cr = Components.results;
 Cu.import("resource://gre/modules/PageThumbs.jsm");
 // Page for which the start UI is shown
 const kStartURI = "about:newtab";
 // allow panning after this timeout on pages with registered touch listeners
 const kTouchTimeout = 300;
 const kSetInactiveStateTimeout = 100;
 const kTabThumbnailDelayCapture = 500;
 const XUL_NS = "http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul";
 // See grid.xml, we use this to cache style info across loads of the startui.
 var _richgridTileSizes = {};
 // Override sizeToContent in the main window. It breaks things (bug 565887)
 window.sizeToContent = function() {
   Cu.reportError("window.sizeToContent is not allowed in this window");
 }
 function getTabModalPromptBox(aWindow) {
   let browser = Browser.getBrowserForWindow(aWindow);
   return Browser.getTabModalPromptBox(browser);
 }
 /*
  * Returns the browser for the currently displayed tab.
  */
 function getBrowser() {
   return Browser.selectedBrowser;
 }
 var Browser = {
   _debugEvents: false,
   _tabs: [],
   _selectedTab: null,
   _tabId: 0,
   windowUtils: window.QueryInterface(Ci.nsIInterfaceRequestor)
                      .getInterface(Ci.nsIDOMWindowUtils),
   get defaultBrowserWidth() {
     return window.innerWidth;
   },
   startup: function startup() {
     var self = this;
     try {
       messageManager.loadFrameScript("chrome://browser/content/Util.js", true);
       messageManager.loadFrameScript("chrome://browser/content/contenthandlers/Content.js", true);
       messageManager.loadFrameScript("chrome://browser/content/contenthandlers/FormHelper.js", true);
       messageManager.loadFrameScript("chrome://browser/content/library/SelectionPrototype.js", true);
       messageManager.loadFrameScript("chrome://browser/content/contenthandlers/SelectionHandler.js", true);
       messageManager.loadFrameScript("chrome://browser/content/contenthandlers/ContextMenuHandler.js", true);
       messageManager.loadFrameScript("chrome://browser/content/contenthandlers/ConsoleAPIObserver.js", true);
       messageManager.loadFrameScript("chrome://browser/content/contenthandlers/PluginHelper.js", true);
     } catch (e) {
       // XXX whatever is calling startup needs to dump errors!
       dump("###########" + e + "\n");
     }
     if (!Services.metro) {
       // Services.metro is only available on Windows Metro. We want to be able
       // to test metro on other platforms, too, so we provide a minimal shim.
       Services.metro = {
         activationURI: "",
         pinTileAsync: function () {},
         unpinTileAsync: function () {}
       };
     }
     /* handles dispatching clicks on browser into clicks in content or zooms */
     Elements.browsers.customDragger = new Browser.MainDragger();
     /* handles web progress management for open browsers */
     Elements.browsers.webProgress = WebProgress.init();
     // Call InputSourceHelper first so global listeners get called before
     // we start processing input in TouchModule.
     InputSourceHelper.init();
     ClickEventHandler.init();
     TouchModule.init();
     GestureModule.init();
     BrowserTouchHandler.init();
     PopupBlockerObserver.init();
     APZCObserver.init();
     // Init the touch scrollbox
     this.contentScrollbox = Elements.browsers;
     this.contentScrollboxScroller = {
       scrollBy: function(aDx, aDy) {
         let view = getBrowser().getRootView();
         view.scrollBy(aDx, aDy);
       },
       scrollTo: function(aX, aY) {
         let view = getBrowser().getRootView();
         view.scrollTo(aX, aY);
       },
       getPosition: function(aScrollX, aScrollY) {
         let view = getBrowser().getRootView();
         let scroll = view.getPosition();
         aScrollX.value = scroll.x;
         aScrollY.value = scroll.y;
       }
     };
     ContentAreaObserver.init();
     function fullscreenHandler() {
       if (Browser.selectedBrowser.contentWindow.document.mozFullScreenElement)
         Elements.stack.setAttribute("fullscreen", "true");
       else
         Elements.stack.removeAttribute("fullscreen");
     }
     window.addEventListener("mozfullscreenchange", fullscreenHandler, true);
     BrowserUI.init();
     window.controllers.appendController(this);
     window.controllers.appendController(BrowserUI);
     Services.obs.addObserver(SessionHistoryObserver, "browser:purge-session-history", false);
     window.QueryInterface(Ci.nsIDOMChromeWindow).browserDOMWindow = new nsBrowserAccess();
     Elements.browsers.addEventListener("DOMUpdatePageReport", PopupBlockerObserver.onUpdatePageReport, false);
     // Make sure we're online before attempting to load
     Util.forceOnline();
     // If this is an intial window launch the commandline handler passes us the default
     // page as an argument.
     let commandURL = null;
     try {
       let argsObj = window.arguments[0].wrappedJSObject;
       if (argsObj && argsObj.pageloadURL) {
         // Talos tp-cmdline parameter
         commandURL = argsObj.pageloadURL;
       } else if (window.arguments && window.arguments[0]) {
         // BrowserCLH paramerter
         commandURL = window.arguments[0];
       }
     } catch (ex) {
       Util.dumpLn(ex);
     }
     messageManager.addMessageListener("DOMLinkAdded", this);
     messageManager.addMessageListener("Browser:FormSubmit", this);
     messageManager.addMessageListener("Browser:CanUnload:Return", this);
     messageManager.addMessageListener("scroll", this);
     messageManager.addMessageListener("Browser:CertException", this);
     messageManager.addMessageListener("Browser:BlockedSite", this);
     Task.spawn(function() {
       // Activation URIs come from protocol activations, secondary tiles, and file activations
       let activationURI = yield this.getShortcutOrURI(Services.metro.activationURI);
       let self = this;
       function loadStartupURI() {
         if (activationURI) {
           let webNav = Ci.nsIWebNavigation;
           let flags = webNav.LOAD_FLAGS_ALLOW_THIRD_PARTY_FIXUP |
                       webNav.LOAD_FLAGS_FIXUP_SCHEME_TYPOS;
           self.addTab(activationURI, true, null, { flags: flags });
         } else {
           let uri = commandURL || Browser.getHomePage();
           self.addTab(uri, true);
         }
       }
       // Should we restore the previous session (crash or some other event)
       let ss = Cc["@mozilla.org/browser/sessionstore;1"]
                .getService(Ci.nsISessionStore);
       let shouldRestore = ss.shouldRestore();
       if (shouldRestore) {
         let bringFront = false;
         // First open any commandline URLs, except the homepage
         if (activationURI && activationURI != kStartURI) {
           this.addTab(activationURI, true, null, { flags: Ci.nsIWebNavigation.LOAD_FLAGS_ALLOW_THIRD_PARTY_FIXUP });
         } else if (commandURL && commandURL != kStartURI) {
           this.addTab(commandURL, true);
         } else {
           bringFront = true;
           // Initial window resizes call functions that assume a tab is in the tab list
           // and restored tabs are added too late. We add a dummy to to satisfy the resize
           // code and then remove the dummy after the session has been restored.
           let dummy = this.addTab("about:blank", true);
           let dummyCleanup = {
             observe: function(aSubject, aTopic, aData) {
               Services.obs.removeObserver(dummyCleanup, "sessionstore-windows-restored");
               if (aData == "fail")
                 loadStartupURI();
               dummy.chromeTab.ignoreUndo = true;
               Browser.closeTab(dummy, { forceClose: true });
             }
           };
           Services.obs.addObserver(dummyCleanup, "sessionstore-windows-restored", false);
         }
         ss.restoreLastSession(bringFront);
       } else {
         loadStartupURI();
       }
       // Notify about our input type
       InputSourceHelper.fireUpdate();
       // Broadcast a UIReady message so add-ons know we are finished with startup
       let event = document.createEvent("Events");
       event.initEvent("UIReady", true, false);
       window.dispatchEvent(event);
     }.bind(this));
   },
   shutdown: function shutdown() {
     APZCObserver.shutdown();
     BrowserUI.uninit();
     ClickEventHandler.uninit();
     ContentAreaObserver.shutdown();
     Appbar.shutdown();
     messageManager.removeMessageListener("Browser:FormSubmit", this);
     messageManager.removeMessageListener("scroll", this);
     messageManager.removeMessageListener("Browser:CertException", this);
     messageManager.removeMessageListener("Browser:BlockedSite", this);
     Services.obs.removeObserver(SessionHistoryObserver, "browser:purge-session-history");
     window.controllers.removeController(this);
     window.controllers.removeController(BrowserUI);
   },
   getHomePage: function getHomePage(aOptions) {
     aOptions = aOptions || { useDefault: false };
     let url = kStartURI;
     try {
       let prefs = aOptions.useDefault ? Services.prefs.getDefaultBranch(null) : Services.prefs;
       url = prefs.getComplexValue("browser.startup.homepage", Ci.nsIPrefLocalizedString).data;
     }
     catch(e) { }
     return url;
   },
   get browsers() {
     return this._tabs.map(function(tab) { return tab.browser; });
   },
   /**
    * Load a URI in the current tab, or a new tab if necessary.
    * @param aURI String
    * @param aParams Object with optional properties that will be passed to loadURIWithFlags:
    *    flags, referrerURI, charset, postData.
    */
   loadURI: function loadURI(aURI, aParams) {
     let browser = this.selectedBrowser;
     // We need to keep about: pages opening in new "local" tabs. We also want to spawn
     // new "remote" tabs if opening web pages from a "local" about: page.
     dump("loadURI=" + aURI + "\ncurrentURI=" + browser.currentURI.spec + "\n");
     let params = aParams || {};
     try {
       let flags = params.flags || Ci.nsIWebNavigation.LOAD_FLAGS_NONE;
       let postData = ("postData" in params && params.postData) ? params.postData.value : null;
       let referrerURI = "referrerURI" in params ? params.referrerURI : null;
       let charset = "charset" in params ? params.charset : null;
       dump("loading tab: " + aURI + "\n");
       browser.loadURIWithFlags(aURI, flags, referrerURI, charset, postData);
     } catch(e) {
       dump("Error: " + e + "\n");
     }
   },
   /**
    * Determine if the given URL is a shortcut/keyword and, if so, expand it
    * @param aURL String
    * @param aPostDataRef Out param contains any required post data for a search
    * @return {Promise}
    * @result the expanded shortcut, or the original URL if not a shortcut
    */
   getShortcutOrURI: function getShortcutOrURI(aURL, aPostDataRef) {
     return Task.spawn(function() {
       if (!aURL)
         throw new Task.Result(aURL);
       let shortcutURL = null;
       let keyword = aURL;
       let param = "";
       let offset = aURL.indexOf(" ");
       if (offset > 0) {
         keyword = aURL.substr(0, offset);
         param = aURL.substr(offset + 1);
       }
       if (!aPostDataRef)
         aPostDataRef = {};
       let engine = Services.search.getEngineByAlias(keyword);
       if (engine) {
         let submission = engine.getSubmission(param);
         aPostDataRef.value = submission.postData;
         throw new Task.Result(submission.uri.spec);
       }
       try {
         [shortcutURL, aPostDataRef.value] = PlacesUtils.getURLAndPostDataForKeyword(keyword);
       } catch (e) {}
       if (!shortcutURL)
         throw new Task.Result(aURL);
       let postData = "";
       if (aPostDataRef.value)
         postData = unescape(aPostDataRef.value);
       if (/%s/i.test(shortcutURL) || /%s/i.test(postData)) {
         let charset = "";
         const re = /^(.*)\&mozcharset=([a-zA-Z][_\-a-zA-Z0-9]+)\s*$/;
         let matches = shortcutURL.match(re);
         if (matches)
           [, shortcutURL, charset] = matches;
         else {
           // Try to get the saved character-set.
           try {
             // makeURI throws if URI is invalid.
             // Will return an empty string if character-set is not found.
             charset = yield PlacesUtils.getCharsetForURI(Util.makeURI(shortcutURL));
           } catch (e) { dump("--- error " + e + "\n"); }
         }
         let encodedParam = "";
         if (charset)
           encodedParam = escape(convertFromUnicode(charset, param));
         else // Default charset is UTF-8
           encodedParam = encodeURIComponent(param);
         shortcutURL = shortcutURL.replace(/%s/g, encodedParam).replace(/%S/g, param);
         if (/%s/i.test(postData)) // POST keyword
           aPostDataRef.value = getPostDataStream(postData, param, encodedParam, "application/x-www-form-urlencoded");
       } else if (param) {
         // This keyword doesn't take a parameter, but one was provided. Just return
         // the original URL.
         aPostDataRef.value = null;
         throw new Task.Result(aURL);
       }
       throw new Task.Result(shortcutURL);
     });
   },
   /**
    * Return the currently active <browser> object
    */
   get selectedBrowser() {
     return (this._selectedTab && this._selectedTab.browser);
   },
   get tabs() {
     return this._tabs;
   },
   getTabModalPromptBox: function(aBrowser) {
     let browser = (aBrowser || getBrowser());
     let stack = browser.parentNode;
     let self = this;
     let promptBox = {
       appendPrompt : function(args, onCloseCallback) {
           let newPrompt = document.createElementNS(XUL_NS, "tabmodalprompt");
           newPrompt.setAttribute("promptType", args.promptType);
           stack.appendChild(newPrompt);
           browser.setAttribute("tabmodalPromptShowing", true);
           newPrompt.clientTop; // style flush to assure binding is attached
           let tab = self.getTabForBrowser(browser);
           tab = tab.chromeTab;
           newPrompt.metroInit(args, tab, onCloseCallback);
           return newPrompt;
       },
       removePrompt : function(aPrompt) {
           stack.removeChild(aPrompt);
           let prompts = this.listPrompts();
           if (prompts.length) {
           let prompt = prompts[prompts.length - 1];
               prompt.Dialog.setDefaultFocus();
           } else {
               browser.removeAttribute("tabmodalPromptShowing");
               browser.focus();
           }
       },
       listPrompts : function(aPrompt) {
           let els = stack.getElementsByTagNameNS(XUL_NS, "tabmodalprompt");
           // NodeList --> real JS array
           let prompts = Array.slice(els);
           return prompts;
       },
     };
     return promptBox;
   },
   getBrowserForWindowId: function getBrowserForWindowId(aWindowId) {
     for (let i = 0; i < this.browsers.length; i++) {
       if (this.browsers[i].contentWindowId == aWindowId)
         return this.browsers[i];
     }
     return null;
   },
   getBrowserForWindow: function(aWindow) {
     let windowID = aWindow.QueryInterface(Ci.nsIInterfaceRequestor)
                           .getInterface(Ci.nsIDOMWindowUtils).currentInnerWindowID;
     return this.getBrowserForWindowId(windowID);
   },
   getTabForBrowser: function getTabForBrowser(aBrowser) {
     let tabs = this._tabs;
     for (let i = 0; i < tabs.length; i++) {
       if (tabs[i].browser == aBrowser)
         return tabs[i];
     }
     return null;
   },
   getTabAtIndex: function getTabAtIndex(index) {
     if (index >= this._tabs.length || index < 0)
       return null;
     return this._tabs[index];
   },
   getTabFromChrome: function getTabFromChrome(chromeTab) {
     for (var t = 0; t < this._tabs.length; t++) {
       if (this._tabs[t].chromeTab == chromeTab)
         return this._tabs[t];
     }
     return null;
   },
   createTabId: function createTabId() {
     return this._tabId++;
   },
   /**
    * Create a new tab and add it to the tab list.
    *
    * If you are opening a new foreground tab in response to a user action, use
    * BrowserUI.addAndShowTab which will also show the tab strip.
    *
    * @param aURI String specifying the URL to load.
    * @param aBringFront Boolean (optional) Open the new tab in the foreground?
    * @param aOwner Tab object (optional) The "parent" of the new tab.
    *   This is the tab responsible for opening the new tab.  When the new tab
    *   is closed, we will return to a parent or "sibling" tab if possible.
    * @param aParams Object (optional) with optional properties:
    *   index: Number specifying where in the tab list to insert the new tab.
    *   private: If true, the new tab should be have Private Browsing active.
    *   flags, postData, charset, referrerURI: See loadURIWithFlags.
    */
   addTab: function browser_addTab(aURI, aBringFront, aOwner, aParams) {
     let params = aParams || {};
     if (aOwner && !('index' in params)) {
       // Position the new tab to the right of its owner...
       params.index = this._tabs.indexOf(aOwner) + 1;
       // ...and to the right of any siblings.
       while (this._tabs[params.index] && this._tabs[params.index].owner == aOwner) {
         params.index++;
       }
     }
     let newTab = new Tab(aURI, params, aOwner);
     if (params.index >= 0) {
       this._tabs.splice(params.index, 0, newTab);
     } else {
       this._tabs.push(newTab);
     }
     if (aBringFront)
       this.selectedTab = newTab;
     this._announceNewTab(newTab);
     return newTab;
   },
   closeTab: function closeTab(aTab, aOptions) {
     let tab = aTab instanceof XULElement ? this.getTabFromChrome(aTab) : aTab;
     if (!tab) {
       return;
     }
     if (aOptions && "forceClose" in aOptions && aOptions.forceClose) {
       this._doCloseTab(tab);
       return;
     }
     tab.browser.messageManager.sendAsyncMessage("Browser:CanUnload", {});
   },
   savePage: function() {
     ContentAreaUtils.saveDocument(this.selectedBrowser.contentWindow.document);
   },
   /*
    * helper for addTab related methods. Fires events related to
    * new tab creation.
    */
   _announceNewTab: function (aTab) {
     let event = document.createEvent("UIEvents");
     event.initUIEvent("TabOpen", true, false, window, 0);
     aTab.chromeTab.dispatchEvent(event);
     aTab.browser.messageManager.sendAsyncMessage("Browser:TabOpen");
   },
   _doCloseTab: function _doCloseTab(aTab) {
     if (this._tabs.length === 1) {
       Browser.addTab(this.getHomePage());
     }
     let nextTab = this.getNextTab(aTab);
     // Tabs owned by the closed tab are now orphaned.
     this._tabs.forEach(function(item, index, array) {
       if (item.owner == aTab)
         item.owner = null;
     });
     // tray tab
     let event = document.createEvent("Events");
     event.initEvent("TabClose", true, false);
     aTab.chromeTab.dispatchEvent(event);
     // tab window
     event = document.createEvent("Events");
     event.initEvent("TabClose", true, false);
     aTab.browser.contentWindow.dispatchEvent(event);
     aTab.browser.messageManager.sendAsyncMessage("Browser:TabClose");
     let container = aTab.chromeTab.parentNode;
     aTab.destroy();
     this._tabs.splice(this._tabs.indexOf(aTab), 1);
     this.selectedTab = nextTab;
     event = document.createEvent("Events");
     event.initEvent("TabRemove", true, false);
     container.dispatchEvent(event);
   },
   getNextTab: function getNextTab(aTab) {
     let tabIndex = this._tabs.indexOf(aTab);
     if (tabIndex == -1)
       return null;
     if (this._selectedTab == aTab || this._selectedTab.chromeTab.hasAttribute("closing")) {
       let nextTabIndex = tabIndex + 1;
       let nextTab = null;
       while (nextTabIndex < this._tabs.length && (!nextTab || nextTab.chromeTab.hasAttribute("closing"))) {
         nextTab = this.getTabAtIndex(nextTabIndex);
         nextTabIndex++;
       }
       nextTabIndex = tabIndex - 1;
       while (nextTabIndex >= 0 && (!nextTab || nextTab.chromeTab.hasAttribute("closing"))) {
         nextTab = this.getTabAtIndex(nextTabIndex);
         nextTabIndex--;
       }
       if (!nextTab || nextTab.chromeTab.hasAttribute("closing"))
         return null;
       // If the next tab is not a sibling, switch back to the parent.
       if (aTab.owner && nextTab.owner != aTab.owner)
         nextTab = aTab.owner;
       if (!nextTab)
         return null;
       return nextTab;
     }
     return this._selectedTab;
   },
   get selectedTab() {
     return this._selectedTab;
   },
   set selectedTab(tab) {
     if (tab instanceof XULElement)
       tab = this.getTabFromChrome(tab);
     if (!tab)
       return;
     if (this._selectedTab == tab) {
       // Deck does not update its selectedIndex when children
       // are removed. See bug 602708
       Elements.browsers.selectedPanel = tab.notification;
       return;
     }
     let isFirstTab = this._selectedTab == null;
     let lastTab = this._selectedTab;
     let browser = tab.browser;
     this._selectedTab = tab;
     if (lastTab)
       lastTab.active = false;
     if (tab)
       tab.active = true;
     BrowserUI.update();
     if (isFirstTab) {
       BrowserUI._titleChanged(browser);
     } else {
       // Update all of our UI to reflect the new tab's location
       BrowserUI.updateURI();
       let event = document.createEvent("Events");
       event.initEvent("TabSelect", true, false);
       event.lastTab = lastTab;
       tab.chromeTab.dispatchEvent(event);
     }
     tab.lastSelected = Date.now();
   },
   supportsCommand: function(cmd) {
     return false;
   },
   isCommandEnabled: function(cmd) {
     return false;
   },
   doCommand: function(cmd) {
   },
   getNotificationBox: function getNotificationBox(aBrowser) {
     let browser = aBrowser || this.selectedBrowser;
     return browser.parentNode.parentNode;
   },
   /**
    * Handle cert exception message from content.
    */
   _handleCertException: function _handleCertException(aMessage) {
     let json = aMessage.json;
     if (json.action == "leave") {
       // Get the start page from the *default* pref branch, not the user's
       let url = Browser.getHomePage({ useDefault: true });
       this.loadURI(url);
     } else {
       // Handle setting an cert exception and reloading the page
       try {
         // Add a new SSL exception for this URL
         let uri = Services.io.newURI(json.url, null, null);
         let sslExceptions = new SSLExceptions();
         if (json.action == "permanent")
           sslExceptions.addPermanentException(uri, window);
         else
           sslExceptions.addTemporaryException(uri, window);
       } catch (e) {
         dump("EXCEPTION handle content command: " + e + "\n" );
       }
       // Automatically reload after the exception was added
       aMessage.target.reload();
     }
   },
   /**
    * Handle blocked site message from content.
    */
   _handleBlockedSite: function _handleBlockedSite(aMessage) {
     let formatter = Cc["@mozilla.org/toolkit/URLFormatterService;1"].getService(Ci.nsIURLFormatter);
     let json = aMessage.json;
     switch (json.action) {
       case "leave": {
         // Get the start page from the *default* pref branch, not the user's
         let url = Browser.getHomePage({ useDefault: true });
         this.loadURI(url);
         break;
       }
       case "report-malware": {
         // Get the stop badware "why is this blocked" report url, append the current url, and go there.
         try {
           let reportURL = formatter.formatURLPref("browser.safebrowsing.malware.reportURL");
           reportURL += json.url;
           this.loadURI(reportURL);
         } catch (e) {
           Cu.reportError("Couldn't get malware report URL: " + e);
         }
         break;
       }
       case "report-phishing": {
         // It's a phishing site, just link to the generic information page
         let url = Services.urlFormatter.formatURLPref("app.support.baseURL");
         this.loadURI(url + "phishing-malware");
         break;
       }
     }
   },
   pinSite: function browser_pinSite() {
     // Get a path to our app tile
     var file = Components.classes["@mozilla.org/file/directory_service;1"].
            getService(Components.interfaces.nsIProperties).
            get("CurProcD", Components.interfaces.nsIFile);
     // Get rid of the current working directory's metro subidr
     file = file.parent;
     file.append("tileresources");
     file.append("VisualElements_logo.png");
     var ios = Components.classes["@mozilla.org/network/io-service;1"].
               getService(Components.interfaces.nsIIOService);
     var uriSpec = ios.newFileURI(file).spec;
     Services.metro.pinTileAsync(this._currentPageTileID,
                                 Browser.selectedBrowser.contentTitle, // short name
                                 Browser.selectedBrowser.contentTitle, // display name
                                 "-url " + Browser.selectedBrowser.currentURI.spec,
                             uriSpec, uriSpec);
   },
   get _currentPageTileID() {
     // We use a unique ID per URL, so just use an MD5 hash of the URL as the ID.
     let hasher = Cc["@mozilla.org/security/hash;1"].
                  createInstance(Ci.nsICryptoHash);
     hasher.init(Ci.nsICryptoHash.MD5);
     let stringStream = Cc["@mozilla.org/io/string-input-stream;1"].
                        createInstance(Ci.nsIStringInputStream);
     stringStream.data = Browser.selectedBrowser.currentURI.spec;
     hasher.updateFromStream(stringStream, -1);
     let hashASCII = hasher.finish(true);
     // Replace '/' with a valid filesystem character
     return ("FFTileID_" + hashASCII).replace('/', '_', 'g');
   },
   unpinSite: function browser_unpinSite() {
     if (!Services.metro.immersive)
       return;
     Services.metro.unpinTileAsync(this._currentPageTileID);
   },
   isSitePinned: function browser_isSitePinned() {
     if (!Services.metro.immersive)
       return false;
     return Services.metro.isTilePinned(this._currentPageTileID);
   },
   starSite: function browser_starSite(callback) {
     let uri = this.selectedBrowser.currentURI;
     let title = this.selectedBrowser.contentTitle;
     Bookmarks.addForURI(uri, title, callback);
   },
   unstarSite: function browser_unstarSite(callback) {
     let uri = this.selectedBrowser.currentURI;
     Bookmarks.removeForURI(uri, callback);
   },
   isSiteStarredAsync: function browser_isSiteStarredAsync(callback) {
     let uri = this.selectedBrowser.currentURI;
     Bookmarks.isURIBookmarked(uri, callback);
   },
   /**
    * Convenience function for getting the scrollbox position off of a
    * scrollBoxObject interface.  Returns the actual values instead of the
    * wrapping objects.
    *
    * @param scroller a scrollBoxObject on which to call scroller.getPosition()
    */
   getScrollboxPosition: function getScrollboxPosition(scroller) {
     let x = {};
     let y = {};
     scroller.getPosition(x, y);
     return new Point(x.value, y.value);
   },
   forceChromeReflow: function forceChromeReflow() {
     let dummy = getComputedStyle(document.documentElement, "").width;
   },
   receiveMessage: function receiveMessage(aMessage) {
     let json = aMessage.json;
     let browser = aMessage.target;
     switch (aMessage.name) {
       case "DOMLinkAdded": {
         // checks for an icon to use for a web app
         // apple-touch-icon size is 57px and default size is 16px
         let rel = json.rel.toLowerCase().split(" ");
         if (rel.indexOf("icon") != -1) {
           // We use the sizes attribute if available
           // see http://www.whatwg.org/specs/web-apps/current-work/multipage/links.html#rel-icon
           let size = 16;
           if (json.sizes) {
             let sizes = json.sizes.toLowerCase().split(" ");
             sizes.forEach(function(item) {
               if (item != "any") {
                 let [w, h] = item.split("x");
                 size = Math.max(Math.min(w, h), size);
               }
             });
           }
           if (size > browser.appIcon.size) {
             browser.appIcon.href = json.href;
             browser.appIcon.size = size;
           }
         }
         else if ((rel.indexOf("apple-touch-icon") != -1) && (browser.appIcon.size < 57)) {
           // XXX should we support apple-touch-icon-precomposed ?
           // see http://developer.apple.com/safari/library/documentation/appleapplications/reference/safariwebcontent/configuringwebapplications/configuringwebapplications.html
           browser.appIcon.href = json.href;
           browser.appIcon.size = 57;
         }
         break;
       }
       case "Browser:FormSubmit":
         browser.lastLocation = null;
         break;
       case "Browser:CanUnload:Return": {
         if (json.permit) {
           let tab = this.getTabForBrowser(browser);
           BrowserUI.animateClosingTab(tab);
         }
         break;
       }
       case "Browser:CertException":
         this._handleCertException(aMessage);
         break;
       case "Browser:BlockedSite":
         this._handleBlockedSite(aMessage);
         break;
     }
   },
 };
 Browser.MainDragger = function MainDragger() {
   this._horizontalScrollbar = document.getElementById("horizontal-scroller");
   this._verticalScrollbar = document.getElementById("vertical-scroller");
   this._scrollScales = { x: 0, y: 0 };
   Elements.browsers.addEventListener("PanBegin", this, false);
   Elements.browsers.addEventListener("PanFinished", this, false);
 };
 Browser.MainDragger.prototype = {
   isDraggable: function isDraggable(target, scroller) {
     return { x: true, y: true };
   },
   dragStart: function dragStart(clientX, clientY, target, scroller) {
     let browser = getBrowser();
     let bcr = browser.getBoundingClientRect();
     this._contentView = browser.getViewAt(clientX - bcr.left, clientY - bcr.top);
   },
   dragStop: function dragStop(dx, dy, scroller) {
     if (this._contentView && this._contentView._updateCacheViewport)
       this._contentView._updateCacheViewport();
     this._contentView = null;
   },
   dragMove: function dragMove(dx, dy, scroller, aIsKinetic) {
     let doffset = new Point(dx, dy);
     this._panContent(doffset);
     if (aIsKinetic && doffset.x != 0)
       return false;
     this._updateScrollbars();
     return !doffset.equals(dx, dy);
   },
   handleEvent: function handleEvent(aEvent) {
     let browser = getBrowser();
     switch (aEvent.type) {
       case "PanBegin": {
         let width = ContentAreaObserver.width, height = ContentAreaObserver.height;
         let contentWidth = browser.contentDocumentWidth * browser.scale;
         let contentHeight = browser.contentDocumentHeight * browser.scale;
         // Allow a small margin on both sides to prevent adding scrollbars
         // on small viewport approximation
         const ALLOWED_MARGIN = 5;
         const SCROLL_CORNER_SIZE = 8;
         this._scrollScales = {
           x: (width + ALLOWED_MARGIN) < contentWidth ? (width - SCROLL_CORNER_SIZE) / contentWidth : 0,
           y: (height + ALLOWED_MARGIN) < contentHeight ? (height - SCROLL_CORNER_SIZE) / contentHeight : 0
         }
         this._showScrollbars();
         break;
       }
       case "PanFinished":
         this._hideScrollbars();
         // Update the scroll position of the content
         browser._updateCSSViewport();
         break;
     }
   },
   _panContent: function md_panContent(aOffset) {
     if (this._contentView && !this._contentView.isRoot()) {
       this._panContentView(this._contentView, aOffset);
       // XXX we may need to have "escape borders" for iframe panning
       // XXX does not deal with scrollables within scrollables
     }
     // Do content panning
     this._panContentView(getBrowser().getRootView(), aOffset);
   },
   /** Pan scroller by the given amount. Updates doffset with leftovers. */
   _panContentView: function _panContentView(contentView, doffset) {
     let pos0 = contentView.getPosition();
     contentView.scrollBy(doffset.x, doffset.y);
     let pos1 = contentView.getPosition();
     doffset.subtract(pos1.x - pos0.x, pos1.y - pos0.y);
   },
   _updateScrollbars: function _updateScrollbars() {
     let scaleX = this._scrollScales.x, scaleY = this._scrollScales.y;
     let contentScroll = Browser.getScrollboxPosition(Browser.contentScrollboxScroller);
     if (scaleX)
       this._horizontalScrollbar.style.MozTransform =
         "translateX(" + Math.round(contentScroll.x * scaleX) + "px)";
     if (scaleY) {
       let y = Math.round(contentScroll.y * scaleY);
       let x = 0;
       this._verticalScrollbar.style.MozTransform =
         "translate(" + x + "px," + y + "px)";
     }
   },
   _showScrollbars: function _showScrollbars() {
     this._updateScrollbars();
     let scaleX = this._scrollScales.x, scaleY = this._scrollScales.y;
     if (scaleX) {
       this._horizontalScrollbar.width = ContentAreaObserver.width * scaleX;
       this._horizontalScrollbar.setAttribute("panning", "true");
     }
     if (scaleY) {
       this._verticalScrollbar.height = ContentAreaObserver.height * scaleY;
       this._verticalScrollbar.setAttribute("panning", "true");
     }
   },
   _hideScrollbars: function _hideScrollbars() {
     this._scrollScales.x = 0;
     this._scrollScales.y = 0;
     this._horizontalScrollbar.removeAttribute("panning");
     this._verticalScrollbar.removeAttribute("panning");
     this._horizontalScrollbar.removeAttribute("width");
     this._verticalScrollbar.removeAttribute("height");
     this._horizontalScrollbar.style.MozTransform = "";
     this._verticalScrollbar.style.MozTransform = "";
   }
 };
 function nsBrowserAccess() { }
 nsBrowserAccess.prototype = {
   QueryInterface: function(aIID) {
     if (aIID.equals(Ci.nsIBrowserDOMWindow) || aIID.equals(Ci.nsISupports))
       return this;
     throw Cr.NS_NOINTERFACE;
   },
   _getOpenAction: function _getOpenAction(aURI, aOpener, aWhere, aContext) {
     let where = aWhere;
     /*
      * aWhere:
      * OPEN_DEFAULTWINDOW: default action
      * OPEN_CURRENTWINDOW: current window/tab
      * OPEN_NEWWINDOW: not allowed, converted to newtab below
      * OPEN_NEWTAB: open a new tab
      * OPEN_SWITCHTAB: open in an existing tab if it matches, otherwise open
      * a new tab. afaict we always open these in the current tab.
      */
     if (where == Ci.nsIBrowserDOMWindow.OPEN_DEFAULTWINDOW) {
       // query standard browser prefs indicating what to do for default action
       switch (aContext) {
         // indicates this is an open request from a 3rd party app.
         case Ci.nsIBrowserDOMWindow.OPEN_EXTERNAL :
           where = Services.prefs.getIntPref("browser.link.open_external");
           break;
         // internal request
         default :
           where = Services.prefs.getIntPref("browser.link.open_newwindow");
       }
     }
     if (where == Ci.nsIBrowserDOMWindow.OPEN_NEWWINDOW) {
       Util.dumpLn("Invalid request - we can't open links in new windows.");
       where = Ci.nsIBrowserDOMWindow.OPEN_NEWTAB;
     }
     return where;
   },
   _getBrowser: function _getBrowser(aURI, aOpener, aWhere, aContext) {
     let isExternal = (aContext == Ci.nsIBrowserDOMWindow.OPEN_EXTERNAL);
     // We don't allow externals apps opening chrome docs
     if (isExternal && aURI && aURI.schemeIs("chrome"))
       return null;
     let location;
     let browser;
     let loadflags = isExternal ?
                       Ci.nsIWebNavigation.LOAD_FLAGS_FROM_EXTERNAL :
                       Ci.nsIWebNavigation.LOAD_FLAGS_NONE;
     let openAction = this._getOpenAction(aURI, aOpener, aWhere, aContext);
     if (openAction == Ci.nsIBrowserDOMWindow.OPEN_NEWTAB) {
       let owner = isExternal ? null : Browser.selectedTab;
       let tab = BrowserUI.openLinkInNewTab("about:blank", true, owner);
       browser = tab.browser;
     } else {
       browser = Browser.selectedBrowser;
     }
     try {
       let referrer;
       if (aURI && browser) {
         if (aOpener) {
           location = aOpener.location;
           referrer = Services.io.newURI(location, null, null);
         }
         browser.loadURIWithFlags(aURI.spec, loadflags, referrer, null, null);
       }
       browser.focus();
     } catch(e) { }
     return browser;
   },
   openURI: function browser_openURI(aURI, aOpener, aWhere, aContext) {
     let browser = this._getBrowser(aURI, aOpener, aWhere, aContext);
     return browser ? browser.contentWindow : null;
   },
   openURIInFrame: function browser_openURIInFrame(aURI, aOpener, aWhere, aContext) {
     let browser = this._getBrowser(aURI, aOpener, aWhere, aContext);
     return browser ? browser.QueryInterface(Ci.nsIFrameLoaderOwner) : null;
   },
   isTabContentWindow: function(aWindow) {
     return Browser.browsers.some(function (browser) browser.contentWindow == aWindow);
   },
   get contentWindow() {
     return Browser.selectedBrowser.contentWindow;
   }
 };
 /**
  * Handler for blocked popups, triggered by DOMUpdatePageReport events in browser.xml
  */
 var PopupBlockerObserver = {
   init: function init() {
     Elements.browsers.addEventListener("mousedown", this, true);
   },
   handleEvent: function handleEvent(aEvent) {
     switch (aEvent.type) {
       case "mousedown":
         let box = Browser.getNotificationBox();
         let notification = box.getNotificationWithValue("popup-blocked");
         if (notification && !notification.contains(aEvent.target))
           box.removeNotification(notification);
         break;
     }
   },
   onUpdatePageReport: function onUpdatePageReport(aEvent) {
     var cBrowser = Browser.selectedBrowser;
     if (aEvent.originalTarget != cBrowser)
       return;
     if (!cBrowser.pageReport)
       return;
     let result = Services.perms.testExactPermission(Browser.selectedBrowser.currentURI, "popup");
     if (result == Ci.nsIPermissionManager.DENY_ACTION)
       return;
     // Only show the notification again if we've not already shown it. Since
     // notifications are per-browser, we don't need to worry about re-adding
     // it.
     if (!cBrowser.pageReport.reported) {
       if (Services.prefs.getBoolPref("privacy.popups.showBrowserMessage")) {
         var brandShortName = Strings.brand.GetStringFromName("brandShortName");
         var popupCount = cBrowser.pageReport.length;
         let strings = Strings.browser;
         let message = PluralForm.get(popupCount, strings.GetStringFromName("popupWarning.message"))
                                 .replace("#1", brandShortName)
                                 .replace("#2", popupCount);
         var notificationBox = Browser.getNotificationBox();
         var notification = notificationBox.getNotificationWithValue("popup-blocked");
         if (notification) {
           notification.label = message;
         }
         else {
           var buttons = [
             {
               isDefault: false,
               label: strings.GetStringFromName("popupButtonAllowOnce2"),
               accessKey: "",
               callback: function() { PopupBlockerObserver.showPopupsForSite(); }
             },
             {
               label: strings.GetStringFromName("popupButtonAlwaysAllow3"),
               accessKey: "",
               callback: function() { PopupBlockerObserver.allowPopupsForSite(true); }
             },
             {
               label: strings.GetStringFromName("popupButtonNeverWarn3"),
               accessKey: "",
               callback: function() { PopupBlockerObserver.allowPopupsForSite(false); }
             }
           ];
           const priority = notificationBox.PRIORITY_WARNING_MEDIUM;
           notificationBox.appendNotification(message, "popup-blocked",
                                              "chrome://browser/skin/images/infobar-popup.png",
                                              priority, buttons);
         }
       }
       // Record the fact that we've reported this blocked popup, so we don't
       // show it again.
       cBrowser.pageReport.reported = true;
     }
   },
   allowPopupsForSite: function allowPopupsForSite(aAllow) {
     var currentURI = Browser.selectedBrowser.currentURI;
     Services.perms.add(currentURI, "popup", aAllow
                        ?  Ci.nsIPermissionManager.ALLOW_ACTION
                        :  Ci.nsIPermissionManager.DENY_ACTION);
     Browser.getNotificationBox().removeCurrentNotification();
   },
   showPopupsForSite: function showPopupsForSite() {
     let uri = Browser.selectedBrowser.currentURI;
     let pageReport = Browser.selectedBrowser.pageReport;
     if (pageReport) {
       for (let i = 0; i < pageReport.length; ++i) {
         var popupURIspec = pageReport[i].popupWindowURI.spec;
         // Sometimes the popup URI that we get back from the pageReport
         // isn't useful (for instance, netscape.com's popup URI ends up
         // being "http://www.netscape.com", which isn't really the URI of
         // the popup they're trying to show).  This isn't going to be
         // useful to the user, so we won't create a menu item for it.
         if (popupURIspec == "" || !Util.isURLMemorable(popupURIspec) || popupURIspec == uri.spec)
           continue;
         let popupFeatures = pageReport[i].popupWindowFeatures;
         let popupName = pageReport[i].popupWindowName;
         Browser.addTab(popupURIspec, false, Browser.selectedTab);
       }
     }
   }
 };
 var SessionHistoryObserver = {
   observe: function sho_observe(aSubject, aTopic, aData) {
     if (aTopic != "browser:purge-session-history")
       return;
     let newTab = Browser.addTab("about:start", true);
     let tab = Browser._tabs[0];
     while(tab != newTab) {
       Browser.closeTab(tab, { forceClose: true } );
       tab = Browser._tabs[0];
     }
     PlacesUtils.history.removeAllPages();
     // Clear undo history of the URL bar
     BrowserUI._edit.editor.transactionManager.clear();
   }
 };
 function getNotificationBox(aBrowser) {
   return Browser.getNotificationBox(aBrowser);
 }
 function showDownloadManager(aWindowContext, aID, aReason) {
   // TODO: Bug 883962: Toggle the downloads infobar as our current "download manager".
 }
 function Tab(aURI, aParams, aOwner) {
   this._id = null;
   this._browser = null;
   this._notification = null;
   this._loading = false;
   this._progressActive = false;
   this._progressCount = 0;
   this._chromeTab = null;
   this._eventDeferred = null;
   this._updateThumbnailTimeout = null;
   this._private = false;
   if ("private" in aParams) {
     this._private = aParams.private;
   } else if (aOwner) {
     this._private = aOwner._private;
   }
   this.owner = aOwner || null;
   // Set to 0 since new tabs that have not been viewed yet are good tabs to
   // toss if app needs more memory.
   this.lastSelected = 0;
   // aParams is an object that contains some properties for the initial tab
   // loading like flags, a referrerURI, a charset or even a postData.
   this.create(aURI, aParams || {}, aOwner);
   // default tabs to inactive (i.e. no display port)
   this.active = false;
 }
 Tab.prototype = {
   get browser() {
     return this._browser;
   },
   get notification() {
     return this._notification;
   },
   get chromeTab() {
     return this._chromeTab;
   },
   get isPrivate() {
     return this._private;
   },
   get pageShowPromise() {
     return this._eventDeferred ? this._eventDeferred.promise : null;
   },
   startLoading: function startLoading() {
     if (this._loading) {
       let stack = new Error().stack;
       throw "Already Loading!\n" + stack;
     }
     this._loading = true;
   },
   endLoading: function endLoading() {
     this._loading = false;
     this.updateFavicon();
   },
   isLoading: function isLoading() {
     return this._loading;
   },
   create: function create(aURI, aParams, aOwner) {
     this._eventDeferred = Promise.defer();
     this._chromeTab = Elements.tabList.addTab(aParams.index);
     if (this.isPrivate) {
       this._chromeTab.setAttribute("private", "true");
     }
     this._id = Browser.createTabId();
     let browser = this._createBrowser(aURI, null);
     let self = this;
     function onPageShowEvent(aEvent) {
       browser.removeEventListener("pageshow", onPageShowEvent);
       if (self._eventDeferred) {
         self._eventDeferred.resolve(self);
       }
       self._eventDeferred = null;
     }
     browser.addEventListener("pageshow", onPageShowEvent, true);
     browser.addEventListener("DOMWindowCreated", this, false);
     browser.addEventListener("StartUIChange", this, false);
     Elements.browsers.addEventListener("SizeChanged", this, false);
     browser.messageManager.addMessageListener("Content:StateChange", this);
     if (aOwner)
       this._copyHistoryFrom(aOwner);
     this._loadUsingParams(browser, aURI, aParams);
   },
   updateViewport: function (aEvent) {
     // <meta name=viewport> is not yet supported; just use the browser size.
     let browser = this.browser;
     // On the start page we add padding to keep the browser above the navbar.
     let paddingBottom = parseInt(getComputedStyle(browser).paddingBottom, 10);
     let height = browser.clientHeight - paddingBottom;
     browser.setWindowSize(browser.clientWidth, height);
   },
   handleEvent: function (aEvent) {
     switch (aEvent.type) {
       case "DOMWindowCreated":
       case "StartUIChange":
         this.updateViewport();
         break;
       case "SizeChanged":
         this.updateViewport();
         this._delayUpdateThumbnail();
         break;
       case "AlertClose": {
         if (this == Browser.selectedTab) {
           this.updateViewport();
         }
         break;
       }
     }
   },
   receiveMessage: function(aMessage) {
     switch (aMessage.name) {
       case "Content:StateChange":
         // update the thumbnail now...
         this.updateThumbnail();
         // ...and in a little while to capture page after load.
         if (aMessage.json.stateFlags & Ci.nsIWebProgressListener.STATE_STOP) {
           this._delayUpdateThumbnail();
         }
         break;
     }
   },
   _delayUpdateThumbnail: function() {
     clearTimeout(this._updateThumbnailTimeout);
     this._updateThumbnailTimeout = setTimeout(() => {
       this.updateThumbnail();
     }, kTabThumbnailDelayCapture);
   },
   destroy: function destroy() {
     this._browser.messageManager.removeMessageListener("Content:StateChange", this);
     this._browser.removeEventListener("DOMWindowCreated", this, false);
     this._browser.removeEventListener("StartUIChange", this, false);
     Elements.browsers.removeEventListener("SizeChanged", this, false);
     clearTimeout(this._updateThumbnailTimeout);
     Elements.tabList.removeTab(this._chromeTab);
     this._chromeTab = null;
     this._destroyBrowser();
   },
   resurrect: function resurrect() {
     let dead = this._browser;
     let active = this.active;
     // Hold onto the session store data
     let session = { data: dead.__SS_data, extra: dead.__SS_extdata };
     // We need this data to correctly create and position the new browser
     // If this browser is already a zombie, fallback to the session data
     let currentURL = dead.__SS_restore ? session.data.entries[0].url : dead.currentURI.spec;
     let sibling = dead.nextSibling;
     // Destory and re-create the browser
     this._destroyBrowser();
     let browser = this._createBrowser(currentURL, sibling);
     if (active)
       this.active = true;
     // Reattach session store data and flag this browser so it is restored on select
     browser.__SS_data = session.data;
     browser.__SS_extdata = session.extra;
     browser.__SS_restore = true;
   },
   _copyHistoryFrom: function _copyHistoryFrom(tab) {
     let otherHistory = tab._browser._webNavigation.sessionHistory;
     let history = this._browser._webNavigation.sessionHistory;
     // Ensure that history is initialized
     history.QueryInterface(Ci.nsISHistoryInternal);
     for (let i = 0, length = otherHistory.index; i <= length; i++)
       history.addEntry(otherHistory.getEntryAtIndex(i, false), true);
   },
   _loadUsingParams: function _loadUsingParams(aBrowser, aURI, aParams) {
     let flags = aParams.flags || Ci.nsIWebNavigation.LOAD_FLAGS_NONE;
     let postData = ("postData" in aParams && aParams.postData) ? aParams.postData.value : null;
     let referrerURI = "referrerURI" in aParams ? aParams.referrerURI : null;
     let charset = "charset" in aParams ? aParams.charset : null;
     aBrowser.loadURIWithFlags(aURI, flags, referrerURI, charset, postData);
   },
   _createBrowser: function _createBrowser(aURI, aInsertBefore) {
     if (this._browser)
       throw "Browser already exists";
     // Create a notification box around the browser. Note this includes
     // the input overlay we use to shade content from input events when
     // we're intercepting touch input.
     let notification = this._notification = document.createElement("notificationbox");
     let browser = this._browser = document.createElement("browser");
     browser.id = "browser-" + this._id;
     this._chromeTab.linkedBrowser = browser;
     browser.setAttribute("type", "content-targetable");
     let useRemote = Services.appinfo.browserTabsRemote;
     let useLocal = Util.isLocalScheme(aURI);
     browser.setAttribute("remote", (!useLocal && useRemote) ? "true" : "false");
     // Append the browser to the document, which should start the page load
     let stack = document.createElementNS(XUL_NS, "stack");
     stack.className = "browserStack";
     stack.appendChild(browser);
     stack.setAttribute("flex", "1");
     notification.appendChild(stack);
     Elements.browsers.insertBefore(notification, aInsertBefore);
     notification.dir = "reverse";
     notification.addEventListener("AlertClose", this);
      // let the content area manager know about this browser.
     ContentAreaObserver.onBrowserCreated(browser);
     if (this.isPrivate) {
       let ctx = browser.docShell.QueryInterface(Ci.nsILoadContext);
       ctx.usePrivateBrowsing = true;
     }
     // stop about:blank from loading
     browser.stop();
     let fl = browser.QueryInterface(Ci.nsIFrameLoaderOwner).frameLoader;
     fl.renderMode = Ci.nsIFrameLoader.RENDER_MODE_ASYNC_SCROLL;
     return browser;
   },
   _destroyBrowser: function _destroyBrowser() {
     if (this._browser) {
       let notification = this._notification;
       notification.removeEventListener("AlertClose", this);
       let browser = this._browser;
       browser.active = false;
       this._notification = null;
       this._browser = null;
       this._loading = false;
       Elements.browsers.removeChild(notification);
     }
   },
   updateThumbnail: function updateThumbnail() {
     if (!this.isPrivate) {
       PageThumbs.captureToCanvas(this.browser.contentWindow, this._chromeTab.thumbnailCanvas);
     }
   },
   updateFavicon: function updateFavicon() {
     this._chromeTab.updateFavicon(this._browser.mIconURL);
   },
   set active(aActive) {
     if (!this._browser)
       return;
     let notification = this._notification;
     let browser = this._browser;
     if (aActive) {
       notification.classList.add("active-tab-notificationbox");
       browser.setAttribute("type", "content-primary");
       Elements.browsers.selectedPanel = notification;
       browser.active = true;
       Elements.tabList.selectedTab = this._chromeTab;
       browser.focus();
     } else {
       notification.classList.remove("active-tab-notificationbox");
       browser.messageManager.sendAsyncMessage("Browser:Blur", { });
       browser.setAttribute("type", "content-targetable");
       browser.active = false;
     }
   },
   get active() {
     if (!this._browser)
       return false;
     return this._browser.getAttribute("type") == "content-primary";
   },
   toString: function() {
     return "[Tab " + (this._browser ? this._browser.currentURI.spec : "(no browser)") + "]";
   }
 };
 // Helper used to hide IPC / non-IPC differences for rendering to a canvas
 function rendererFactory(aBrowser, aCanvas) {
   let wrapper = {};
   if (aBrowser.contentWindow) {
     let ctx = aCanvas.getContext("2d");
     let draw = function(browser, aLeft, aTop, aWidth, aHeight, aColor, aFlags) {
       ctx.drawWindow(browser.contentWindow, aLeft, aTop, aWidth, aHeight, aColor, aFlags);
       let e = document.createEvent("HTMLEvents");
       e.initEvent("MozAsyncCanvasRender", true, true);
       aCanvas.dispatchEvent(e);
     };
     wrapper.checkBrowser = function(browser) {
       return browser.contentWindow;
     };
     wrapper.drawContent = function(callback) {
       callback(ctx, draw);
     };
   }
   else {
     let ctx = aCanvas.MozGetIPCContext("2d");
     let draw = function(browser, aLeft, aTop, aWidth, aHeight, aColor, aFlags) {
       ctx.asyncDrawXULElement(browser, aLeft, aTop, aWidth, aHeight, aColor, aFlags);
     };
     wrapper.checkBrowser = function(browser) {
       return !browser.contentWindow;
     };
     wrapper.drawContent = function(callback) {
       callback(ctx, draw);
     };
   }
   return wrapper;
 };
 // Based on ClickEventHandler from /browser/base/content/content.js
 let ClickEventHandler = {
   init: function () {
     gEventListenerService.addSystemEventListener(Elements.browsers, "click", this, true);
   },
   uninit: function () {
     gEventListenerService.removeSystemEventListener(Elements.browsers, "click", this, true);
   },
   handleEvent: function (aEvent) {
     if (!aEvent.isTrusted || aEvent.defaultPrevented) {
       return;
     }
     let [href, node] = this._hrefAndLinkNodeForClickEvent(aEvent);
     if (href && (aEvent.button == 1 || aEvent.ctrlKey)) {
       // Open link in a new tab for middle-click or ctrl-click
       BrowserUI.openLinkInNewTab(href, aEvent.shiftKey, Browser.selectedTab);
     }
   },
   /**
    * Extracts linkNode and href for the current click target.
    *
    * @param event
    *        The click event.
    * @return [href, linkNode].
    *
    * @note linkNode will be null if the click wasn't on an anchor
    *       element (or XLink).
    */
   _hrefAndLinkNodeForClickEvent: function(event) {
     function isHTMLLink(aNode) {
       return ((aNode instanceof content.HTMLAnchorElement && aNode.href) ||
               (aNode instanceof content.HTMLAreaElement && aNode.href) ||
               aNode instanceof content.HTMLLinkElement);
     }
     let node = event.target;
     while (node && !isHTMLLink(node)) {
       node = node.parentNode;
     }
     if (node)
       return [node.href, node];
     // If there is no linkNode, try simple XLink.
     let href, baseURI;
     node = event.target;
     while (node && !href) {
       if (node.nodeType == content.Node.ELEMENT_NODE) {
         href = node.getAttributeNS("http://www.w3.org/1999/xlink", "href");
         if (href)
           baseURI = node.ownerDocument.baseURIObject;
       }
       node = node.parentNode;
     }
     // In case of XLink, we don't return the node we got href from since
     // callers expect <a>-like elements.
     // Note: makeURI() will throw if aUri is not a valid URI.
     return [href ? Services.io.newURI(href, null, baseURI).spec : null, null];
   }
 };