The Tor Browser / file revision

 /* This Source Code Form is subject to the terms of the Mozilla Public

  * License, v. 2.0. If a copy of the MPL was not distributed with this

  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

 "use strict";

 this.EXPORTED_SYMBOLS = ["CustomizableUI"];

 const {classes: Cc, interfaces: Ci, utils: Cu, results: Cr} = Components;

 Cu.import("resource://gre/modules/Services.jsm");

 Cu.import("resource://gre/modules/XPCOMUtils.jsm");

 XPCOMUtils.defineLazyModuleGetter(this, "PanelWideWidgetTracker",

   "resource:///modules/PanelWideWidgetTracker.jsm");

 XPCOMUtils.defineLazyModuleGetter(this, "CustomizableWidgets",

   "resource:///modules/CustomizableWidgets.jsm");

 XPCOMUtils.defineLazyModuleGetter(this, "DeferredTask",

   "resource://gre/modules/DeferredTask.jsm");

 XPCOMUtils.defineLazyModuleGetter(this, "PrivateBrowsingUtils",

   "resource://gre/modules/PrivateBrowsingUtils.jsm");

 XPCOMUtils.defineLazyModuleGetter(this, "Promise",

   "resource://gre/modules/Promise.jsm");

 XPCOMUtils.defineLazyGetter(this, "gWidgetsBundle", function() {

   const kUrl = "chrome://browser/locale/customizableui/customizableWidgets.properties";

   return Services.strings.createBundle(kUrl);

 });

 XPCOMUtils.defineLazyModuleGetter(this, "ShortcutUtils",

   "resource://gre/modules/ShortcutUtils.jsm");

 XPCOMUtils.defineLazyServiceGetter(this, "gELS",

   "@mozilla.org/eventlistenerservice;1", "nsIEventListenerService");

 const kNSXUL = "http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul";

 const kSpecialWidgetPfx = "customizableui-special-";

 const kPrefCustomizationState        = "browser.uiCustomization.state";

 const kPrefCustomizationAutoAdd      = "browser.uiCustomization.autoAdd";

 const kPrefCustomizationDebug        = "browser.uiCustomization.debug";

 const kPrefDrawInTitlebar            = "browser.tabs.drawInTitlebar";

 /**

  * The keys are the handlers that are fired when the event type (the value)

  * is fired on the subview. A widget that provides a subview has the option

  * of providing onViewShowing and onViewHiding event handlers.

  */

 const kSubviewEvents = [

   "ViewShowing",

   "ViewHiding"

 ];

 /**

  * gPalette is a map of every widget that CustomizableUI.jsm knows about, keyed

  * on their IDs.

  */

 let gPalette = new Map();

 /**

  * gAreas maps area IDs to Sets of properties about those areas. An area is a

  * place where a widget can be put.

  */

 let gAreas = new Map();

 /**

  * gPlacements maps area IDs to Arrays of widget IDs, indicating that the widgets

  * are placed within that area (either directly in the area node, or in the

  * customizationTarget of the node).

  */

 let gPlacements = new Map();

 /**

  * gFuturePlacements represent placements that will happen for areas that have

  * not yet loaded (due to lazy-loading). This can occur when add-ons register

  * widgets.

  */

 let gFuturePlacements = new Map();

 //XXXunf Temporary. Need a nice way to abstract functions to build widgets

 //       of these types.

 let gSupportedWidgetTypes = new Set(["button", "view", "custom"]);

 /**

  * gPanelsForWindow is a list of known panels in a window which we may need to close

  * should command events fire which target them.

  */

 let gPanelsForWindow = new WeakMap();

 /**

  * gSeenWidgets remembers which widgets the user has seen for the first time

  * before. This way, if a new widget is created, and the user has not seen it

  * before, it can be put in its default location. Otherwise, it remains in the

  * palette.

  */

 let gSeenWidgets = new Set();

 /**

  * gDirtyAreaCache is a set of area IDs for areas where items have been added,

  * moved or removed at least once. This set is persisted, and is used to

  * optimize building of toolbars in the default case where no toolbars should

  * be "dirty".

  */

 let gDirtyAreaCache = new Set();

 /**

  * gPendingBuildAreas is a map from area IDs to map from build nodes to their

  * existing children at the time of node registration, that are waiting

  * for the area to be registered

  */

 let gPendingBuildAreas = new Map();

 let gSavedState = null;

 let gRestoring = false;

 let gDirty = false;

 let gInBatchStack = 0;

 let gResetting = false;

 let gUndoResetting = false;

 /**

  * gBuildAreas maps area IDs to actual area nodes within browser windows.

  */

 let gBuildAreas = new Map();

 /**

  * gBuildWindows is a map of windows that have registered build areas, mapped

  * to a Set of known toolboxes in that window.

  */

 let gBuildWindows = new Map();

 let gNewElementCount = 0;

 let gGroupWrapperCache = new Map();

 let gSingleWrapperCache = new WeakMap();

 let gListeners = new Set();

 let gUIStateBeforeReset = {

   uiCustomizationState: null,

   drawInTitlebar: null,

 };

 let gModuleName = "[CustomizableUI]";

 #include logging.js

 let CustomizableUIInternal = {

   initialize: function() {

     LOG("Initializing");

     this.addListener(this);

     this._defineBuiltInWidgets();

     this.loadSavedState();

     let panelPlacements = [

       "edit-controls",

       "zoom-controls",

       "new-window-button",

       "privatebrowsing-button",

       "save-page-button",

       "print-button",

       "history-panelmenu",

       "fullscreen-button",

       "find-button",

       "preferences-button",

       "add-ons-button",

       "developer-button",

     ];

     if (gPalette.has("switch-to-metro-button")) {

       panelPlacements.push("switch-to-metro-button");

     }

 #ifdef NIGHTLY_BUILD

     if (gPalette.has("e10s-button")) {

       let newWindowIndex = panelPlacements.indexOf("new-window-button");

       if (newWindowIndex > -1) {

         panelPlacements.splice(newWindowIndex + 1, 0, "e10s-button");

       }

     }

 #endif

     let showCharacterEncoding = Services.prefs.getComplexValue(

       "browser.menu.showCharacterEncoding",

       Ci.nsIPrefLocalizedString

     ).data;

     if (showCharacterEncoding == "true") {

       panelPlacements.push("characterencoding-button");

     }

     this.registerArea(CustomizableUI.AREA_PANEL, {

       anchor: "PanelUI-menu-button",

       type: CustomizableUI.TYPE_MENU_PANEL,

       defaultPlacements: panelPlacements

     }, true);

     PanelWideWidgetTracker.init();

     this.registerArea(CustomizableUI.AREA_NAVBAR, {

       legacy: true,

       type: CustomizableUI.TYPE_TOOLBAR,

       overflowable: true,

       defaultPlacements: [

         "urlbar-container",

         "search-container",

         "webrtc-status-button",

         "bookmarks-menu-button",

         "downloads-button",

         "home-button",

         "social-share-button",

       ],

       defaultCollapsed: false,

     }, true);

 #ifndef XP_MACOSX

     this.registerArea(CustomizableUI.AREA_MENUBAR, {

       legacy: true,

       type: CustomizableUI.TYPE_TOOLBAR,

       defaultPlacements: [

         "menubar-items",

       ],

       get defaultCollapsed() {

 #ifdef MENUBAR_CAN_AUTOHIDE

 #if defined(MOZ_WIDGET_GTK) || defined(MOZ_WIDGET_QT)

         return true;

 #else

         // This is duplicated logic from /browser/base/jar.mn

         // for win6BrowserOverlay.xul.

         return Services.appinfo.OS == "WINNT" &&

                Services.sysinfo.getProperty("version") != "5.1";

 #endif

 #endif

         return false;

       }

     }, true);

 #endif

     this.registerArea(CustomizableUI.AREA_TABSTRIP, {

       legacy: true,

       type: CustomizableUI.TYPE_TOOLBAR,

       defaultPlacements: [

         "tabbrowser-tabs",

         "new-tab-button",

         "alltabs-button",

       ],

       defaultCollapsed: null,

     }, true);

     this.registerArea(CustomizableUI.AREA_BOOKMARKS, {

       legacy: true,

       type: CustomizableUI.TYPE_TOOLBAR,

       defaultPlacements: [

         "personal-bookmarks",

       ],

       defaultCollapsed: true,

     }, true);

     this.registerArea(CustomizableUI.AREA_ADDONBAR, {

       type: CustomizableUI.TYPE_TOOLBAR,

       legacy: true,

       defaultPlacements: ["addonbar-closebutton", "status-bar"],

       defaultCollapsed: false,

     }, true);

   },

   get _builtinToolbars() {

     return new Set([

       CustomizableUI.AREA_NAVBAR,

       CustomizableUI.AREA_BOOKMARKS,

       CustomizableUI.AREA_TABSTRIP,

       CustomizableUI.AREA_ADDONBAR,

 #ifndef XP_MACOSX

       CustomizableUI.AREA_MENUBAR,

 #endif

     ]);

   },

   _defineBuiltInWidgets: function() {

     //XXXunf Need to figure out how to auto-add new builtin widgets in new

     //       app versions to already customized areas.

     for (let widgetDefinition of CustomizableWidgets) {

       this.createBuiltinWidget(widgetDefinition);

     }

   },

   wrapWidget: function(aWidgetId) {

     if (gGroupWrapperCache.has(aWidgetId)) {

       return gGroupWrapperCache.get(aWidgetId);

     }

     let provider = this.getWidgetProvider(aWidgetId);

     if (!provider) {

       return null;

     }

     if (provider == CustomizableUI.PROVIDER_API) {

       let widget = gPalette.get(aWidgetId);

       if (!widget.wrapper) {

         widget.wrapper = new WidgetGroupWrapper(widget);

         gGroupWrapperCache.set(aWidgetId, widget.wrapper);

       }

       return widget.wrapper;

     }

     // PROVIDER_SPECIAL gets treated the same as PROVIDER_XUL.

     let wrapper = new XULWidgetGroupWrapper(aWidgetId);

     gGroupWrapperCache.set(aWidgetId, wrapper);

     return wrapper;

   },

   registerArea: function(aName, aProperties, aInternalCaller) {

     if (typeof aName != "string" || !/^[a-z0-9-_]{1,}$/i.test(aName)) {

       throw new Error("Invalid area name");

     }

     let areaIsKnown = gAreas.has(aName);

     let props = areaIsKnown ? gAreas.get(aName) : new Map();

     const kImmutableProperties = new Set(["type", "legacy", "overflowable"]);

     for (let key in aProperties) {

       if (areaIsKnown && kImmutableProperties.has(key) &&

           props.get(key) != aProperties[key]) {

         throw new Error("An area cannot change the property for '" + key + "'");

       }

       //XXXgijs for special items, we need to make sure they have an appropriate ID

       // so we aren't perpetually in a non-default state:

       if (key == "defaultPlacements" && Array.isArray(aProperties[key])) {

         props.set(key, aProperties[key].map(x => this.isSpecialWidget(x) ? this.ensureSpecialWidgetId(x) : x ));

       } else {

         props.set(key, aProperties[key]);

       }

     }

     // Default to a toolbar:

     if (!props.has("type")) {

       props.set("type", CustomizableUI.TYPE_TOOLBAR);

     }

     if (props.get("type") == CustomizableUI.TYPE_TOOLBAR) {

       // Check aProperties instead of props because this check is only interested

       // in the passed arguments, not the state of a potentially pre-existing area.

       if (!aInternalCaller && aProperties["defaultCollapsed"]) {

         throw new Error("defaultCollapsed is only allowed for default toolbars.")

       }

       if (!props.has("defaultCollapsed")) {

         props.set("defaultCollapsed", true);

       }

     } else if (props.has("defaultCollapsed")) {

       throw new Error("defaultCollapsed only applies for TYPE_TOOLBAR areas.");

     }

     // Sanity check type:

     let allTypes = [CustomizableUI.TYPE_TOOLBAR, CustomizableUI.TYPE_MENU_PANEL];

     if (allTypes.indexOf(props.get("type")) == -1) {

       throw new Error("Invalid area type " + props.get("type"));

     }

     // And to no placements:

     if (!props.has("defaultPlacements")) {

       props.set("defaultPlacements", []);

     }

     // Sanity check default placements array:

     if (!Array.isArray(props.get("defaultPlacements"))) {

       throw new Error("Should provide an array of default placements");

     }

     if (!areaIsKnown) {

       gAreas.set(aName, props);

       if (props.get("legacy") && !gPlacements.has(aName)) {

         // Guarantee this area exists in gFuturePlacements, to avoid checking it in

         // various places elsewhere.

         gFuturePlacements.set(aName, new Set());

       } else {

         this.restoreStateForArea(aName);

       }

       // If we have pending build area nodes, register all of them

       if (gPendingBuildAreas.has(aName)) {

         let pendingNodes = gPendingBuildAreas.get(aName);

         for (let [pendingNode, existingChildren] of pendingNodes) {

           this.registerToolbarNode(pendingNode, existingChildren);

         }

         gPendingBuildAreas.delete(aName);

       }

     }

   },

   unregisterArea: function(aName, aDestroyPlacements) {

     if (typeof aName != "string" || !/^[a-z0-9-_]{1,}$/i.test(aName)) {

       throw new Error("Invalid area name");

     }

     if (!gAreas.has(aName) && !gPlacements.has(aName)) {

       throw new Error("Area not registered");

     }

     // Move all the widgets out

     this.beginBatchUpdate();

     try {

       let placements = gPlacements.get(aName);

       if (placements) {

         // Need to clone this array so removeWidgetFromArea doesn't modify it

         placements = [...placements];

         placements.forEach(this.removeWidgetFromArea, this);

       }

       // Delete all remaining traces.

       gAreas.delete(aName);

       // Only destroy placements when necessary:

       if (aDestroyPlacements) {

         gPlacements.delete(aName);

       } else {

         // Otherwise we need to re-set them, as removeFromArea will have emptied

         // them out:

         gPlacements.set(aName, placements);

       }

       gFuturePlacements.delete(aName);

       let existingAreaNodes = gBuildAreas.get(aName);

       if (existingAreaNodes) {

         for (let areaNode of existingAreaNodes) {

           this.notifyListeners("onAreaNodeUnregistered", aName, areaNode.customizationTarget,

                                CustomizableUI.REASON_AREA_UNREGISTERED);

         }

       }

       gBuildAreas.delete(aName);

     } finally {

       this.endBatchUpdate(true);

     }

   },

   registerToolbarNode: function(aToolbar, aExistingChildren) {

     let area = aToolbar.id;

     if (gBuildAreas.has(area) && gBuildAreas.get(area).has(aToolbar)) {

       return;

     }

     let document = aToolbar.ownerDocument;

     let areaProperties = gAreas.get(area);

     // If this area is not registered, try to do it automatically:

     if (!areaProperties) {

       // If there's no defaultset attribute and this isn't a legacy extra toolbar,

       // we assume that we should wait for registerArea to be called:

       if (!aToolbar.hasAttribute("defaultset") &&

           !aToolbar.hasAttribute("customindex")) {

         if (!gPendingBuildAreas.has(area)) {

           gPendingBuildAreas.set(area, new Map());

         }

         let pendingNodes = gPendingBuildAreas.get(area);

         pendingNodes.set(aToolbar, aExistingChildren);

         return;

       }

       let props = {type: CustomizableUI.TYPE_TOOLBAR, legacy: true};

       let defaultsetAttribute = aToolbar.getAttribute("defaultset") || "";

       props.defaultPlacements = defaultsetAttribute.split(',').filter(s => s);

       this.registerArea(area, props);

       areaProperties = gAreas.get(area);

     }

     this.beginBatchUpdate();

     try {

       let placements = gPlacements.get(area);

       if (!placements && areaProperties.has("legacy")) {

         let legacyState = aToolbar.getAttribute("currentset");

         if (legacyState) {

           legacyState = legacyState.split(",").filter(s => s);

         }

         // Manually restore the state here, so the legacy state can be converted. 

         this.restoreStateForArea(area, legacyState);

         placements = gPlacements.get(area);

       }

       // Check that the current children and the current placements match. If

       // not, mark it as dirty:

       if (aExistingChildren.length != placements.length ||

           aExistingChildren.every((id, i) => id == placements[i])) {

         gDirtyAreaCache.add(area);

       }

       if (areaProperties.has("overflowable")) {

         aToolbar.overflowable = new OverflowableToolbar(aToolbar);

       }

       this.registerBuildArea(area, aToolbar);

       // We only build the toolbar if it's been marked as "dirty". Dirty means

       // one of the following things:

       // 1) Items have been added, moved or removed from this toolbar before.

       // 2) The number of children of the toolbar does not match the length of

       //    the placements array for that area.

       //

       // This notion of being "dirty" is stored in a cache which is persisted

       // in the saved state.

       if (gDirtyAreaCache.has(area)) {

         this.buildArea(area, placements, aToolbar);

       }

       this.notifyListeners("onAreaNodeRegistered", area, aToolbar.customizationTarget);

       aToolbar.setAttribute("currentset", placements.join(","));

     } finally {

       this.endBatchUpdate();

     }

   },

   buildArea: function(aArea, aPlacements, aAreaNode) {

     let document = aAreaNode.ownerDocument;

     let window = document.defaultView;

     let inPrivateWindow = PrivateBrowsingUtils.isWindowPrivate(window);

     let container = aAreaNode.customizationTarget;

     let areaIsPanel = gAreas.get(aArea).get("type") == CustomizableUI.TYPE_MENU_PANEL;

     if (!container) {

       throw new Error("Expected area " + aArea

                       + " to have a customizationTarget attribute.");

     }

     // Restore nav-bar visibility since it may have been hidden

     // through a migration path (bug 938980) or an add-on.

     if (aArea == CustomizableUI.AREA_NAVBAR) {

       aAreaNode.collapsed = false;

     }

     this.beginBatchUpdate();

     try {

       let currentNode = container.firstChild;

       let placementsToRemove = new Set();

       for (let id of aPlacements) {

         while (currentNode && currentNode.getAttribute("skipintoolbarset") == "true") {

           currentNode = currentNode.nextSibling;

         }

         if (currentNode && currentNode.id == id) {

           currentNode = currentNode.nextSibling;

           continue;

         }

         if (this.isSpecialWidget(id) && areaIsPanel) {

           placementsToRemove.add(id);

           continue;

         }

         let [provider, node] = this.getWidgetNode(id, window);

         if (!node) {

           LOG("Unknown widget: " + id);

           continue;

         }

         // If the placements have items in them which are (now) no longer removable,

         // we shouldn't be moving them:

         if (provider == CustomizableUI.PROVIDER_API) {

           let widgetInfo = gPalette.get(id);

           if (!widgetInfo.removable && aArea != widgetInfo.defaultArea) {

             placementsToRemove.add(id);

             continue;

           }

         } else if (provider == CustomizableUI.PROVIDER_XUL &&

                    node.parentNode != container && !this.isWidgetRemovable(node)) {

           placementsToRemove.add(id);

           continue;

         } // Special widgets are always removable, so no need to check them

         if (inPrivateWindow && provider == CustomizableUI.PROVIDER_API) {

           let widget = gPalette.get(id);

           if (!widget.showInPrivateBrowsing && inPrivateWindow) {

             continue;

           }

         }

         this.ensureButtonContextMenu(node, aAreaNode);

         if (node.localName == "toolbarbutton") {

           if (areaIsPanel) {

             node.setAttribute("wrap", "true");

           } else {

             node.removeAttribute("wrap");

           }

         }

         this.insertWidgetBefore(node, currentNode, container, aArea);

         if (gResetting) {

           this.notifyListeners("onWidgetReset", node, container);

         } else if (gUndoResetting) {

           this.notifyListeners("onWidgetUndoMove", node, container);

         }

       }

       if (currentNode) {

         let palette = aAreaNode.toolbox ? aAreaNode.toolbox.palette : null;

         let limit = currentNode.previousSibling;

         let node = container.lastChild;

         while (node && node != limit) {

           let previousSibling = node.previousSibling;

           // Nodes opt-in to removability. If they're removable, and we haven't

           // seen them in the placements array, then we toss them into the palette

           // if one exists. If no palette exists, we just remove the node. If the

           // node is not removable, we leave it where it is. However, we can only

           // safely touch elements that have an ID - both because we depend on

           // IDs, and because such elements are not intended to be widgets

           // (eg, titlebar-placeholder elements).

           if (node.id && node.getAttribute("skipintoolbarset") != "true") {

             if (this.isWidgetRemovable(node)) {

               if (palette && !this.isSpecialWidget(node.id)) {

                 palette.appendChild(node);

                 this.removeLocationAttributes(node);

               } else {

                 container.removeChild(node);

               }

             } else {

               this.setLocationAttributes(currentNode, aArea);

               node.setAttribute("removable", false);

               LOG("Adding non-removable widget to placements of " + aArea + ": " +

                   node.id);

               gPlacements.get(aArea).push(node.id);

               gDirty = true;

             }

           }

           node = previousSibling;

         }

       }

       // If there are placements in here which aren't removable from their original area,

       // we remove them from this area's placement array. They will (have) be(en) added

       // to their original area's placements array in the block above this one.

       if (placementsToRemove.size) {

         let placementAry = gPlacements.get(aArea);

         for (let id of placementsToRemove) {

           let index = placementAry.indexOf(id);

           placementAry.splice(index, 1);

         }

       }

       if (gResetting) {

         this.notifyListeners("onAreaReset", aArea, container);

       }

     } finally {

       this.endBatchUpdate();

     }

   },

   addPanelCloseListeners: function(aPanel) {

     gELS.addSystemEventListener(aPanel, "click", this, false);

     gELS.addSystemEventListener(aPanel, "keypress", this, false);

     let win = aPanel.ownerDocument.defaultView;

     if (!gPanelsForWindow.has(win)) {

       gPanelsForWindow.set(win, new Set());

     }

     gPanelsForWindow.get(win).add(this._getPanelForNode(aPanel));

   },

   removePanelCloseListeners: function(aPanel) {

     gELS.removeSystemEventListener(aPanel, "click", this, false);

     gELS.removeSystemEventListener(aPanel, "keypress", this, false);

     let win = aPanel.ownerDocument.defaultView;

     let panels = gPanelsForWindow.get(win);

     if (panels) {

       panels.delete(this._getPanelForNode(aPanel));

     }

   },

   ensureButtonContextMenu: function(aNode, aAreaNode) {

     const kPanelItemContextMenu = "customizationPanelItemContextMenu";

     let currentContextMenu = aNode.getAttribute("context") ||

                              aNode.getAttribute("contextmenu");

     let place = CustomizableUI.getPlaceForItem(aAreaNode);

     let contextMenuForPlace = place == "panel" ?

                                 kPanelItemContextMenu :

                                 null;

     if (contextMenuForPlace && !currentContextMenu) {

       aNode.setAttribute("context", contextMenuForPlace);

     } else if (currentContextMenu == kPanelItemContextMenu &&

                contextMenuForPlace != kPanelItemContextMenu) {

       aNode.removeAttribute("context");

       aNode.removeAttribute("contextmenu");

     }

   },

   getWidgetProvider: function(aWidgetId) {

     if (this.isSpecialWidget(aWidgetId)) {

       return CustomizableUI.PROVIDER_SPECIAL;

     }

     if (gPalette.has(aWidgetId)) {

       return CustomizableUI.PROVIDER_API;

     }

     // If this was an API widget that was destroyed, return null:

     if (gSeenWidgets.has(aWidgetId)) {

       return null;

     }

     // We fall back to the XUL provider, but we don't know for sure (at this

     // point) whether it exists there either. So the API is technically lying.

     // Ideally, it would be able to return an error value (or throw an

     // exception) if it really didn't exist. Our code calling this function

     // handles that fine, but this is a public API.

     return CustomizableUI.PROVIDER_XUL;

   },

   getWidgetNode: function(aWidgetId, aWindow) {

     let document = aWindow.document;

     if (this.isSpecialWidget(aWidgetId)) {

       let widgetNode = document.getElementById(aWidgetId) ||

                        this.createSpecialWidget(aWidgetId, document);

       return [ CustomizableUI.PROVIDER_SPECIAL, widgetNode];

     }

     let widget = gPalette.get(aWidgetId);

     if (widget) {

       // If we have an instance of this widget already, just use that.

       if (widget.instances.has(document)) {

         LOG("An instance of widget " + aWidgetId + " already exists in this "

             + "document. Reusing.");

         return [ CustomizableUI.PROVIDER_API,

                  widget.instances.get(document) ];

       }

       return [ CustomizableUI.PROVIDER_API,

                this.buildWidget(document, widget) ];

     }

     LOG("Searching for " + aWidgetId + " in toolbox.");

     let node = this.findWidgetInWindow(aWidgetId, aWindow);

     if (node) {

       return [ CustomizableUI.PROVIDER_XUL, node ];

     }

     LOG("No node for " + aWidgetId + " found.");

     return [null, null];

   },

   registerMenuPanel: function(aPanelContents) {

     if (gBuildAreas.has(CustomizableUI.AREA_PANEL) &&

         gBuildAreas.get(CustomizableUI.AREA_PANEL).has(aPanelContents)) {

       return;

     }

     let document = aPanelContents.ownerDocument;

     aPanelContents.toolbox = document.getElementById("navigator-toolbox");

     aPanelContents.customizationTarget = aPanelContents;

     this.addPanelCloseListeners(this._getPanelForNode(aPanelContents));

     let placements = gPlacements.get(CustomizableUI.AREA_PANEL);

     this.buildArea(CustomizableUI.AREA_PANEL, placements, aPanelContents);

     this.notifyListeners("onAreaNodeRegistered", CustomizableUI.AREA_PANEL, aPanelContents);

     for (let child of aPanelContents.children) {

       if (child.localName != "toolbarbutton") {

         if (child.localName == "toolbaritem") {

           this.ensureButtonContextMenu(child, aPanelContents);

         }

         continue;

       }

       this.ensureButtonContextMenu(child, aPanelContents);

       child.setAttribute("wrap", "true");

     }

     this.registerBuildArea(CustomizableUI.AREA_PANEL, aPanelContents);

   },

   onWidgetAdded: function(aWidgetId, aArea, aPosition) {

     this.insertNode(aWidgetId, aArea, aPosition, true);

     if (!gResetting) {

       this._clearPreviousUIState();

     }

   },

   onWidgetRemoved: function(aWidgetId, aArea) {

     let areaNodes = gBuildAreas.get(aArea);

     if (!areaNodes) {

       return;

     }

     let area = gAreas.get(aArea);

     let isToolbar = area.get("type") == CustomizableUI.TYPE_TOOLBAR;

     let isOverflowable = isToolbar && area.get("overflowable");

     let showInPrivateBrowsing = gPalette.has(aWidgetId)

                               ? gPalette.get(aWidgetId).showInPrivateBrowsing

                               : true;

     for (let areaNode of areaNodes) {

       let window = areaNode.ownerDocument.defaultView;

       if (!showInPrivateBrowsing &&

           PrivateBrowsingUtils.isWindowPrivate(window)) {

         continue;

       }

       let widgetNode = window.document.getElementById(aWidgetId);

       if (!widgetNode) {

         INFO("Widget not found, unable to remove");

         continue;

       }

       let container = areaNode.customizationTarget;

       if (isOverflowable) {

         container = areaNode.overflowable.getContainerFor(widgetNode);

       }

       this.notifyListeners("onWidgetBeforeDOMChange", widgetNode, null, container, true);

       // We remove location attributes here to make sure they're gone too when a

       // widget is removed from a toolbar to the palette. See bug 930950.

       this.removeLocationAttributes(widgetNode);

       // We also need to remove the panel context menu if it's there:

       this.ensureButtonContextMenu(widgetNode);

       widgetNode.removeAttribute("wrap");

       if (gPalette.has(aWidgetId) || this.isSpecialWidget(aWidgetId)) {

         container.removeChild(widgetNode);

       } else {

         areaNode.toolbox.palette.appendChild(widgetNode);

       }

       this.notifyListeners("onWidgetAfterDOMChange", widgetNode, null, container, true);

       if (isToolbar) {

         areaNode.setAttribute("currentset", gPlacements.get(aArea).join(','));

       }

       let windowCache = gSingleWrapperCache.get(window);

       if (windowCache) {

         windowCache.delete(aWidgetId);

       }

     }

     if (!gResetting) {

       this._clearPreviousUIState();

     }

   },

   onWidgetMoved: function(aWidgetId, aArea, aOldPosition, aNewPosition) {

     this.insertNode(aWidgetId, aArea, aNewPosition);

     if (!gResetting) {

       this._clearPreviousUIState();

     }

   },

   onCustomizeEnd: function(aWindow) {

     this._clearPreviousUIState();

   },

   registerBuildArea: function(aArea, aNode) {

     // We ensure that the window is registered to have its customization data

     // cleaned up when unloading.

     let window = aNode.ownerDocument.defaultView;

     if (window.closed) {

       return;

     }

     this.registerBuildWindow(window);

     // Also register this build area's toolbox.

     if (aNode.toolbox) {

       gBuildWindows.get(window).add(aNode.toolbox);

     }

     if (!gBuildAreas.has(aArea)) {

       gBuildAreas.set(aArea, new Set());

     }

     gBuildAreas.get(aArea).add(aNode);

     // Give a class to all customize targets to be used for styling in Customize Mode

     let customizableNode = this.getCustomizeTargetForArea(aArea, window);

     customizableNode.classList.add("customization-target");

   },

   registerBuildWindow: function(aWindow) {

     if (!gBuildWindows.has(aWindow)) {

       gBuildWindows.set(aWindow, new Set());

       aWindow.addEventListener("unload", this);

       aWindow.addEventListener("command", this, true);

       this.notifyListeners("onWindowOpened", aWindow);

     }

   },

   unregisterBuildWindow: function(aWindow) {

     aWindow.removeEventListener("unload", this);

     aWindow.removeEventListener("command", this, true);

     gPanelsForWindow.delete(aWindow);

     gBuildWindows.delete(aWindow);

     gSingleWrapperCache.delete(aWindow);

     let document = aWindow.document;

     for (let [areaId, areaNodes] of gBuildAreas) {

       let areaProperties = gAreas.get(areaId);

       for (let node of areaNodes) {

         if (node.ownerDocument == document) {

           this.notifyListeners("onAreaNodeUnregistered", areaId, node.customizationTarget,

                                CustomizableUI.REASON_WINDOW_CLOSED);

           if (areaProperties.has("overflowable")) {

             node.overflowable.uninit();

             node.overflowable = null;

           }

           areaNodes.delete(node);

         }

       }

     }

     for (let [,widget] of gPalette) {

       widget.instances.delete(document);

       this.notifyListeners("onWidgetInstanceRemoved", widget.id, document);

     }

     for (let [area, areaMap] of gPendingBuildAreas) {

       let toDelete = [];

       for (let [areaNode, ] of areaMap) {

         if (areaNode.ownerDocument == document) {

           toDelete.push(areaNode);

         }

       }

       for (let areaNode of toDelete) {

         areaMap.delete(toDelete);

       }

     }

     this.notifyListeners("onWindowClosed", aWindow);

   },

   setLocationAttributes: function(aNode, aArea) {

     let props = gAreas.get(aArea);

     if (!props) {

       throw new Error("Expected area " + aArea + " to have a properties Map " +

                       "associated with it.");

     }

     aNode.setAttribute("cui-areatype", props.get("type") || "");

     let anchor = props.get("anchor");

     if (anchor) {

       aNode.setAttribute("cui-anchorid", anchor);

     } else {

       aNode.removeAttribute("cui-anchorid");

     }

   },

   removeLocationAttributes: function(aNode) {

     aNode.removeAttribute("cui-areatype");

     aNode.removeAttribute("cui-anchorid");

   },

   insertNode: function(aWidgetId, aArea, aPosition, isNew) {

     let areaNodes = gBuildAreas.get(aArea);

     if (!areaNodes) {

       return;

     }

     let placements = gPlacements.get(aArea);

     if (!placements) {

       ERROR("Could not find any placements for " + aArea +

             " when moving a widget.");

       return;

     }

     // Go through each of the nodes associated with this area and move the

     // widget to the requested location.

     for (let areaNode of areaNodes) {

       this.insertNodeInWindow(aWidgetId, areaNode, isNew);

     }

   },

   insertNodeInWindow: function(aWidgetId, aAreaNode, isNew) {

     let window = aAreaNode.ownerDocument.defaultView;

     let showInPrivateBrowsing = gPalette.has(aWidgetId)

                               ? gPalette.get(aWidgetId).showInPrivateBrowsing

                               : true;

     if (!showInPrivateBrowsing && PrivateBrowsingUtils.isWindowPrivate(window)) {

       return;

     }

     let [, widgetNode] = this.getWidgetNode(aWidgetId, window);

     if (!widgetNode) {

       ERROR("Widget '" + aWidgetId + "' not found, unable to move");

       return;

     }

     let areaId = aAreaNode.id;

     if (isNew) {

       this.ensureButtonContextMenu(widgetNode, aAreaNode);

       if (widgetNode.localName == "toolbarbutton" && areaId == CustomizableUI.AREA_PANEL) {

         widgetNode.setAttribute("wrap", "true");

       }

     }

     let [insertionContainer, nextNode] = this.findInsertionPoints(widgetNode, aAreaNode);

     this.insertWidgetBefore(widgetNode, nextNode, insertionContainer, areaId);

     if (gAreas.get(areaId).get("type") == CustomizableUI.TYPE_TOOLBAR) {

       aAreaNode.setAttribute("currentset", gPlacements.get(areaId).join(','));

     }

   },

   findInsertionPoints: function(aNode, aAreaNode) {

     let areaId = aAreaNode.id;

     let props = gAreas.get(areaId);

     // For overflowable toolbars, rely on them (because the work is more complicated):

     if (props.get("type") == CustomizableUI.TYPE_TOOLBAR && props.get("overflowable")) {

       return aAreaNode.overflowable.findOverflowedInsertionPoints(aNode);

     }

     let container = aAreaNode.customizationTarget;

     let placements = gPlacements.get(areaId);

     let nodeIndex = placements.indexOf(aNode.id);

     while (++nodeIndex < placements.length) {

       let nextNodeId = placements[nodeIndex];

       let nextNode = container.getElementsByAttribute("id", nextNodeId).item(0);

       if (nextNode) {

         return [container, nextNode];

       }

     }

     return [container, null];

   },

   insertWidgetBefore: function(aNode, aNextNode, aContainer, aArea) {

     this.notifyListeners("onWidgetBeforeDOMChange", aNode, aNextNode, aContainer);

     this.setLocationAttributes(aNode, aArea);

     aContainer.insertBefore(aNode, aNextNode);

     this.notifyListeners("onWidgetAfterDOMChange", aNode, aNextNode, aContainer);

   },

   handleEvent: function(aEvent) {

     switch (aEvent.type) {

       case "command":

         if (!this._originalEventInPanel(aEvent)) {

           break;

         }

         aEvent = aEvent.sourceEvent;

         // Fall through

       case "click":

       case "keypress":

         this.maybeAutoHidePanel(aEvent);

         break;

       case "unload":

         this.unregisterBuildWindow(aEvent.currentTarget);

         break;

     }

   },

   _originalEventInPanel: function(aEvent) {

     let e = aEvent.sourceEvent;

     if (!e) {

       return false;

     }

     let node = this._getPanelForNode(e.target);

     if (!node) {

       return false;

     }

     let win = e.view;

     let panels = gPanelsForWindow.get(win);

     return !!panels && panels.has(node);

   },

   isSpecialWidget: function(aId) {

     return (aId.startsWith(kSpecialWidgetPfx) ||

             aId.startsWith("separator") ||

             aId.startsWith("spring") ||

             aId.startsWith("spacer"));

   },

   ensureSpecialWidgetId: function(aId) {

     let nodeType = aId.match(/spring|spacer|separator/)[0];

     // If the ID we were passed isn't a generated one, generate one now:

     if (nodeType == aId) {

       // Ids are differentiated through a unique count suffix.

       return kSpecialWidgetPfx + aId + (++gNewElementCount);

     }

     return aId;

   },

   createSpecialWidget: function(aId, aDocument) {

     let nodeName = "toolbar" + aId.match(/spring|spacer|separator/)[0];

     let node = aDocument.createElementNS(kNSXUL, nodeName);

     node.id = this.ensureSpecialWidgetId(aId);

     if (nodeName == "toolbarspring") {

       node.flex = 1;

     }

     return node;

   },

   /* Find a XUL-provided widget in a window. Don't try to use this

    * for an API-provided widget or a special widget.

    */

   findWidgetInWindow: function(aId, aWindow) {

     if (!gBuildWindows.has(aWindow)) {

       throw new Error("Build window not registered");

     }

     if (!aId) {

       ERROR("findWidgetInWindow was passed an empty string.");

       return null;

     }

     let document = aWindow.document;

     // look for a node with the same id, as the node may be

     // in a different toolbar.

     let node = document.getElementById(aId);

     if (node) {

       let parent = node.parentNode;

       while (parent && !(parent.customizationTarget ||

                          parent == aWindow.gNavToolbox.palette)) {

         parent = parent.parentNode;

       }

       if (parent) {

         let nodeInArea = node.parentNode.localName == "toolbarpaletteitem" ?

                          node.parentNode : node;

         // Check if we're in a customization target, or in the palette:

         if ((parent.customizationTarget == nodeInArea.parentNode &&

              gBuildWindows.get(aWindow).has(parent.toolbox)) ||

             aWindow.gNavToolbox.palette == nodeInArea.parentNode) {

           // Normalize the removable attribute. For backwards compat, if

           // the widget is not located in a toolbox palette then absence

           // of the "removable" attribute means it is not removable.

           if (!node.hasAttribute("removable")) {

             // If we first see this in customization mode, it may be in the

             // customization palette instead of the toolbox palette.

             node.setAttribute("removable", !parent.customizationTarget);

           }

           return node;

         }

       }

     }

     let toolboxes = gBuildWindows.get(aWindow);

     for (let toolbox of toolboxes) {

       if (toolbox.palette) {

         // Attempt to locate a node with a matching ID within

         // the palette.

         let node = toolbox.palette.getElementsByAttribute("id", aId)[0];

         if (node) {

           // Normalize the removable attribute. For backwards compat, this

           // is optional if the widget is located in the toolbox palette,

           // and defaults to *true*, unlike if it was located elsewhere.

           if (!node.hasAttribute("removable")) {

             node.setAttribute("removable", true);

           }

           return node;

         }

       }

     }

     return null;

   },

   buildWidget: function(aDocument, aWidget) {

     if (typeof aWidget == "string") {

       aWidget = gPalette.get(aWidget);

     }

     if (!aWidget) {

       throw new Error("buildWidget was passed a non-widget to build.");

     }

     LOG("Building " + aWidget.id + " of type " + aWidget.type);

     let node;

     if (aWidget.type == "custom") {

       if (aWidget.onBuild) {

         node = aWidget.onBuild(aDocument);

       }

       if (!node || !(node instanceof aDocument.defaultView.XULElement))

         ERROR("Custom widget with id " + aWidget.id + " does not return a valid node");

     }

     else {

       if (aWidget.onBeforeCreated) {

         aWidget.onBeforeCreated(aDocument);

       }

       node = aDocument.createElementNS(kNSXUL, "toolbarbutton");

       node.setAttribute("id", aWidget.id);

       node.setAttribute("widget-id", aWidget.id);

       node.setAttribute("widget-type", aWidget.type);

       if (aWidget.disabled) {

         node.setAttribute("disabled", true);

       }

       node.setAttribute("removable", aWidget.removable);

       node.setAttribute("overflows", aWidget.overflows);

       node.setAttribute("label", this.getLocalizedProperty(aWidget, "label"));

       let additionalTooltipArguments = [];

       if (aWidget.shortcutId) {

         let keyEl = aDocument.getElementById(aWidget.shortcutId);

         if (keyEl) {

           additionalTooltipArguments.push(ShortcutUtils.prettifyShortcut(keyEl));

         } else {

           ERROR("Key element with id '" + aWidget.shortcutId + "' for widget '" + aWidget.id +

                 "' not found!");

         }

       }

       let tooltip = this.getLocalizedProperty(aWidget, "tooltiptext", additionalTooltipArguments);

       node.setAttribute("tooltiptext", tooltip);

       node.setAttribute("class", "toolbarbutton-1 chromeclass-toolbar-additional");

       let commandHandler = this.handleWidgetCommand.bind(this, aWidget, node);

       node.addEventListener("command", commandHandler, false);

       let clickHandler = this.handleWidgetClick.bind(this, aWidget, node);

       node.addEventListener("click", clickHandler, false);

       // If the widget has a view, and has view showing / hiding listeners,

       // hook those up to this widget.

       if (aWidget.type == "view") {

         LOG("Widget " + aWidget.id + " has a view. Auto-registering event handlers.");

         let viewNode = aDocument.getElementById(aWidget.viewId);

         if (viewNode) {

           // PanelUI relies on the .PanelUI-subView class to be able to show only

           // one sub-view at a time.

           viewNode.classList.add("PanelUI-subView");

           for (let eventName of kSubviewEvents) {

             let handler = "on" + eventName;

             if (typeof aWidget[handler] == "function") {

               viewNode.addEventListener(eventName, aWidget[handler], false);

             }

           }

           LOG("Widget " + aWidget.id + " showing and hiding event handlers set.");

         } else {

           ERROR("Could not find the view node with id: " + aWidget.viewId +

                 ", for widget: " + aWidget.id + ".");

         }

       }

       if (aWidget.onCreated) {

         aWidget.onCreated(node);

       }

     }

     aWidget.instances.set(aDocument, node);

     return node;

   },

   getLocalizedProperty: function(aWidget, aProp, aFormatArgs, aDef) {

     if (typeof aWidget == "string") {

       aWidget = gPalette.get(aWidget);

     }

     if (!aWidget) {

       throw new Error("getLocalizedProperty was passed a non-widget to work with.");

     }

     let def, name;

     // Let widgets pass their own string identifiers or strings, so that

     // we can use strings which aren't the default (in case string ids change)

     // and so that non-builtin-widgets can also provide labels, tooltips, etc.

     if (aWidget[aProp]) {

       name = aWidget[aProp];

       // By using this as the default, if a widget provides a full string rather

       // than a string ID for localization, we will fall back to that string

       // and return that.

       def = aDef || name;

     } else {

       name = aWidget.id + "." + aProp;

       def = aDef || "";

     }

     try {

       if (Array.isArray(aFormatArgs) && aFormatArgs.length) {

         return gWidgetsBundle.formatStringFromName(name, aFormatArgs,

           aFormatArgs.length) || def;

       }

       return gWidgetsBundle.GetStringFromName(name) || def;

     } catch(ex) {

       if (!def) {

         ERROR("Could not localize property '" + name + "'.");

       }

     }

     return def;

   },

   handleWidgetCommand: function(aWidget, aNode, aEvent) {

     LOG("handleWidgetCommand");

     if (aWidget.type == "button") {

       if (aWidget.onCommand) {

         try {

           aWidget.onCommand.call(null, aEvent);

         } catch (e) {

           ERROR(e);

         }

       } else {

         //XXXunf Need to think this through more, and formalize.

         Services.obs.notifyObservers(aNode,

                                      "customizedui-widget-command",

                                      aWidget.id);

       }

     } else if (aWidget.type == "view") {

       let ownerWindow = aNode.ownerDocument.defaultView;

       let area = this.getPlacementOfWidget(aNode.id).area;

       let anchor = aNode;

       if (area != CustomizableUI.AREA_PANEL) {

         let wrapper = this.wrapWidget(aWidget.id).forWindow(ownerWindow);

         if (wrapper && wrapper.anchor) {

           this.hidePanelForNode(aNode);

           anchor = wrapper.anchor;

         }

       }

       ownerWindow.PanelUI.showSubView(aWidget.viewId, anchor, area);

     }

   },

   handleWidgetClick: function(aWidget, aNode, aEvent) {

     LOG("handleWidgetClick");

     if (aWidget.onClick) {

       try {

         aWidget.onClick.call(null, aEvent);

       } catch(e) {

         Cu.reportError(e);

       }

     } else {

       //XXXunf Need to think this through more, and formalize.

       Services.obs.notifyObservers(aNode, "customizedui-widget-click", aWidget.id);

     }

   },

   _getPanelForNode: function(aNode) {

     let panel = aNode;

     while (panel && panel.localName != "panel")

       panel = panel.parentNode;

     return panel;

   },

   /*

    * If people put things in the panel which need more than single-click interaction,

    * we don't want to close it. Right now we check for text inputs and menu buttons.

    * We also check for being outside of any toolbaritem/toolbarbutton, ie on a blank

    * part of the menu.

    */

   _isOnInteractiveElement: function(aEvent) {

     function getMenuPopupForDescendant(aNode) {

       let lastPopup = null;

       while (aNode && aNode.parentNode &&

              aNode.parentNode.localName.startsWith("menu")) {

         lastPopup = aNode.localName == "menupopup" ? aNode : lastPopup;

         aNode = aNode.parentNode;

       }

       return lastPopup;

     }

     let target = aEvent.originalTarget;

     let panel = this._getPanelForNode(aEvent.currentTarget);

     // This can happen in e.g. customize mode. If there's no panel,

     // there's clearly nothing for us to close; pretend we're interactive.

     if (!panel) {

       return true;

     }

     // We keep track of:

     // whether we're in an input container (text field)

     let inInput = false;

     // whether we're in a popup/context menu

     let inMenu = false;

     // whether we're in a toolbarbutton/toolbaritem

     let inItem = false;

     // whether the current menuitem has a valid closemenu attribute

     let menuitemCloseMenu = "auto";

     // whether the toolbarbutton/item has a valid closemenu attribute.

     let closemenu = "auto";

     // While keeping track of that, we go from the original target back up,

     // to the panel if we have to. We bail as soon as we find an input,

     // a toolbarbutton/item, or the panel:

     while (true && target) {

       let tagName = target.localName;

       inInput = tagName == "input" || tagName == "textbox";

       inItem = tagName == "toolbaritem" || tagName == "toolbarbutton";

       let isMenuItem = tagName == "menuitem";

       inMenu = inMenu || isMenuItem;

       if (inItem && target.hasAttribute("closemenu")) {

         let closemenuVal = target.getAttribute("closemenu");

         closemenu = (closemenuVal == "single" || closemenuVal == "none") ?

                     closemenuVal : "auto";

       }

       if (isMenuItem && target.hasAttribute("closemenu")) {

         let closemenuVal = target.getAttribute("closemenu");

         menuitemCloseMenu = (closemenuVal == "single" || closemenuVal == "none") ?

                             closemenuVal : "auto";

       }

       // This isn't in the loop condition because we want to break before

       // changing |target| if any of these conditions are true

       if (inInput || inItem || target == panel) {

         break;

       }

       // We need specific code for popups: the item on which they were invoked

       // isn't necessarily in their parentNode chain:

       if (isMenuItem) {

         let topmostMenuPopup = getMenuPopupForDescendant(target);

         target = (topmostMenuPopup && topmostMenuPopup.triggerNode) ||

                  target.parentNode;

       } else {

         target = target.parentNode;

       }

     }

     // If the user clicked a menu item...

     if (inMenu) {

       // We care if we're in an input also,

       // or if the user specified closemenu!="auto":

       if (inInput || menuitemCloseMenu != "auto") {

         return true;

       }

       // Otherwise, we're probably fine to close the panel

       return false;

     }

     // If we're not in a menu, and we *are* in a type="menu" toolbarbutton,

     // we'll now interact with the menu

     if (inItem && target.getAttribute("type") == "menu") {

       return true;

     }

     // If we're not in a menu, and we *are* in a type="menu-button" toolbarbutton,

     // it depends whether we're in the dropmarker or the 'real' button:

     if (inItem && target.getAttribute("type") == "menu-button") {

       // 'real' button (which has a single action):

       if (target.getAttribute("anonid") == "button") {

         return closemenu != "none";

       }

       // otherwise, this is the outer button, and the user will now

       // interact with the menu:

       return true;

     }

     return inInput || !inItem;

   },

   hidePanelForNode: function(aNode) {

     let panel = this._getPanelForNode(aNode);

     if (panel) {

       panel.hidePopup();

     }

   },

   maybeAutoHidePanel: function(aEvent) {

     if (aEvent.type == "keypress") {

       if (aEvent.keyCode != aEvent.DOM_VK_RETURN) {

         return;

       }

       // If the user hit enter/return, we don't check preventDefault - it makes sense

       // that this was prevented, but we probably still want to close the panel.

       // If consumers don't want this to happen, they should specify the closemenu

       // attribute.

     } else if (aEvent.type != "command") { // mouse events:

       if (aEvent.defaultPrevented || aEvent.button != 0) {

         return;

       }

       let isInteractive = this._isOnInteractiveElement(aEvent);

       LOG("maybeAutoHidePanel: interactive ? " + isInteractive);

       if (isInteractive) {

         return;

       }

     }

     // We can't use event.target because we might have passed a panelview

     // anonymous content boundary as well, and so target points to the

     // panelmultiview in that case. Unfortunately, this means we get

     // anonymous child nodes instead of the real ones, so looking for the 

     // 'stoooop, don't close me' attributes is more involved.

     let target = aEvent.originalTarget;

     let closemenu = "auto";

     let widgetType = "button";

     while (target.parentNode && target.localName != "panel") {

       closemenu = target.getAttribute("closemenu");

       widgetType = target.getAttribute("widget-type");

       if (closemenu == "none" || closemenu == "single" ||

           widgetType == "view") {

         break;

       }

       target = target.parentNode;

     }

     if (closemenu == "none" || widgetType == "view") {

       return;

     }

     if (closemenu == "single") {

       let panel = this._getPanelForNode(target);

       let multiview = panel.querySelector("panelmultiview");

       if (multiview.showingSubView) {

         multiview.showMainView();

         return;

       }

     }

     // If we get here, we can actually hide the popup:

     this.hidePanelForNode(aEvent.target);

   },

   getUnusedWidgets: function(aWindowPalette) {

     let window = aWindowPalette.ownerDocument.defaultView;

     let isWindowPrivate = PrivateBrowsingUtils.isWindowPrivate(window);

     // We use a Set because there can be overlap between the widgets in

     // gPalette and the items in the palette, especially after the first

     // customization, since programmatically generated widgets will remain

     // in the toolbox palette.

     let widgets = new Set();

     // It's possible that some widgets have been defined programmatically and

     // have not been overlayed into the palette. We can find those inside

     // gPalette.

     for (let [id, widget] of gPalette) {

       if (!widget.currentArea) {

         if (widget.showInPrivateBrowsing || !isWindowPrivate) {

           widgets.add(id);

         }

       }

     }

     LOG("Iterating the actual nodes of the window palette");

     for (let node of aWindowPalette.children) {

       LOG("In palette children: " + node.id);

       if (node.id && !this.getPlacementOfWidget(node.id)) {

         widgets.add(node.id);

       }

     }

     return [...widgets];

   },

   getPlacementOfWidget: function(aWidgetId, aOnlyRegistered, aDeadAreas) {

     if (aOnlyRegistered && !this.widgetExists(aWidgetId)) {

       return null;

     }

     for (let [area, placements] of gPlacements) {

       if (!gAreas.has(area) && !aDeadAreas) {

         continue;

       }

       let index = placements.indexOf(aWidgetId);

       if (index != -1) {

         return { area: area, position: index };

       }

     }

     return null;

   },

   widgetExists: function(aWidgetId) {

     if (gPalette.has(aWidgetId) || this.isSpecialWidget(aWidgetId)) {

       return true;

     }

     // Destroyed API widgets are in gSeenWidgets, but not in gPalette:

     if (gSeenWidgets.has(aWidgetId)) {

       return false;

     }

     // We're assuming XUL widgets always exist, as it's much harder to check,

     // and checking would be much more error prone.

     return true;

   },

   addWidgetToArea: function(aWidgetId, aArea, aPosition, aInitialAdd) {

     if (!gAreas.has(aArea)) {

       throw new Error("Unknown customization area: " + aArea);

     }

     // Hack: don't want special widgets in the panel (need to check here as well

     // as in canWidgetMoveToArea because the menu panel is lazy):

     if (gAreas.get(aArea).get("type") == CustomizableUI.TYPE_MENU_PANEL &&

         this.isSpecialWidget(aWidgetId)) {

       return;

     }

     // If this is a lazy area that hasn't been restored yet, we can't yet modify

     // it - would would at least like to add to it. So we keep track of it in

     // gFuturePlacements,  and use that to add it when restoring the area. We

     // throw away aPosition though, as that can only be bogus if the area hasn't

     // yet been restorted (caller can't possibly know where its putting the

     // widget in relation to other widgets).

     if (this.isAreaLazy(aArea)) {

       gFuturePlacements.get(aArea).add(aWidgetId);

       return;

     }

     if (this.isSpecialWidget(aWidgetId)) {

       aWidgetId = this.ensureSpecialWidgetId(aWidgetId);

     }

     let oldPlacement = this.getPlacementOfWidget(aWidgetId, false, true);

     if (oldPlacement && oldPlacement.area == aArea) {

       this.moveWidgetWithinArea(aWidgetId, aPosition);

       return;

     }

     // Do nothing if the widget is not allowed to move to the target area.

     if (!this.canWidgetMoveToArea(aWidgetId, aArea)) {

       return;

     }

     if (oldPlacement) {

       this.removeWidgetFromArea(aWidgetId);

     }

     if (!gPlacements.has(aArea)) {

       gPlacements.set(aArea, [aWidgetId]);

       aPosition = 0;

     } else {

       let placements = gPlacements.get(aArea);

       if (typeof aPosition != "number") {

         aPosition = placements.length;

       }

       if (aPosition < 0) {

         aPosition = 0;

       }

       placements.splice(aPosition, 0, aWidgetId);

     }

     let widget = gPalette.get(aWidgetId);

     if (widget) {

       widget.currentArea = aArea;

       widget.currentPosition = aPosition;

     }

     // We initially set placements with addWidgetToArea, so in that case

     // we don't consider the area "dirtied".

     if (!aInitialAdd) {

       gDirtyAreaCache.add(aArea);

     }

     gDirty = true;

     this.saveState();

     this.notifyListeners("onWidgetAdded", aWidgetId, aArea, aPosition);

   },

   removeWidgetFromArea: function(aWidgetId) {

     let oldPlacement = this.getPlacementOfWidget(aWidgetId, false, true);

     if (!oldPlacement) {

       return;

     }

     if (!this.isWidgetRemovable(aWidgetId)) {

       return;

     }

     let placements = gPlacements.get(oldPlacement.area);

     let position = placements.indexOf(aWidgetId);

     if (position != -1) {

       placements.splice(position, 1);

     }

     let widget = gPalette.get(aWidgetId);

     if (widget) {

       widget.currentArea = null;

       widget.currentPosition = null;

     }

     gDirty = true;

     this.saveState();

     gDirtyAreaCache.add(oldPlacement.area);

     this.notifyListeners("onWidgetRemoved", aWidgetId, oldPlacement.area);

   },

   moveWidgetWithinArea: function(aWidgetId, aPosition) {

     let oldPlacement = this.getPlacementOfWidget(aWidgetId);

     if (!oldPlacement) {

       return;

     }

     let placements = gPlacements.get(oldPlacement.area);

     if (typeof aPosition != "number") {

       aPosition = placements.length;

     } else if (aPosition < 0) {

       aPosition = 0;

     } else if (aPosition > placements.length) {

       aPosition = placements.length;

     }

     let widget = gPalette.get(aWidgetId);

     if (widget) {

       widget.currentPosition = aPosition;

       widget.currentArea = oldPlacement.area;

     }

     if (aPosition == oldPlacement.position) {

       return;

     }

     placements.splice(oldPlacement.position, 1);

     // If we just removed the item from *before* where it is now added,

     // we need to compensate the position offset for that:

     if (oldPlacement.position < aPosition) {

       aPosition--;

     }

     placements.splice(aPosition, 0, aWidgetId);

     gDirty = true;

     gDirtyAreaCache.add(oldPlacement.area);

     this.saveState();

     this.notifyListeners("onWidgetMoved", aWidgetId, oldPlacement.area,

                          oldPlacement.position, aPosition);

   },

   // Note that this does not populate gPlacements, which is done lazily so that

   // the legacy state can be migrated, which is only available once a browser

   // window is openned.

   // The panel area is an exception here, since it has no legacy state and is 

   // built lazily - and therefore wouldn't otherwise result in restoring its

   // state immediately when a browser window opens, which is important for

   // other consumers of this API.

   loadSavedState: function() {

     let state = null;

     try {

       state = Services.prefs.getCharPref(kPrefCustomizationState);

     } catch (e) {

       LOG("No saved state found");

       // This will fail if nothing has been customized, so silently fall back to

       // the defaults.

     }

     if (!state) {

       return;

     }

     try {

       gSavedState = JSON.parse(state);

       if (typeof gSavedState != "object" || gSavedState === null) {

         throw "Invalid saved state";

       }

     } catch(e) {

       Services.prefs.clearUserPref(kPrefCustomizationState);

       gSavedState = {};

       LOG("Error loading saved UI customization state, falling back to defaults.");

     }

     if (!("placements" in gSavedState)) {

       gSavedState.placements = {};

     }

     gSeenWidgets = new Set(gSavedState.seen || []);

     gDirtyAreaCache = new Set(gSavedState.dirtyAreaCache || []);

     gNewElementCount = gSavedState.newElementCount || 0;

   },

   restoreStateForArea: function(aArea, aLegacyState) {

     let placementsPreexisted = gPlacements.has(aArea);

     this.beginBatchUpdate();

     try {

       gRestoring = true;

       let restored = false;

       if (placementsPreexisted) {

         LOG("Restoring " + aArea + " from pre-existing placements");

         for (let [position, id] in Iterator(gPlacements.get(aArea))) {

           this.moveWidgetWithinArea(id, position);

         }

         gDirty = false;

         restored = true;

       } else {

         gPlacements.set(aArea, []);

       }

       if (!restored && gSavedState && aArea in gSavedState.placements) {

         LOG("Restoring " + aArea + " from saved state");

         let placements = gSavedState.placements[aArea];

         for (let id of placements)

           this.addWidgetToArea(id, aArea);

         gDirty = false;

         restored = true;

       }

       if (!restored && aLegacyState) {

         LOG("Restoring " + aArea + " from legacy state");

         for (let id of aLegacyState)

           this.addWidgetToArea(id, aArea);

         // Don't override dirty state, to ensure legacy state is saved here and

         // therefore only used once.

         restored = true;

       }

       if (!restored) {

         LOG("Restoring " + aArea + " from default state");

         let defaults = gAreas.get(aArea).get("defaultPlacements");

         if (defaults) {

           for (let id of defaults)

             this.addWidgetToArea(id, aArea, null, true);

         }

         gDirty = false;

       }

       // Finally, add widgets to the area that were added before the it was able

       // to be restored. This can occur when add-ons register widgets for a

       // lazily-restored area before it's been restored.

       if (gFuturePlacements.has(aArea)) {

         for (let id of gFuturePlacements.get(aArea))

           this.addWidgetToArea(id, aArea);

       }

       LOG("Placements for " + aArea + ":\n\t" + gPlacements.get(aArea).join("\n\t"));

       gRestoring = false;

     } finally {

       this.endBatchUpdate();

     }

   },

   saveState: function() {

     if (gInBatchStack || !gDirty) {

       return;

     }

     let state = { placements: gPlacements,

                   seen: gSeenWidgets,

                   dirtyAreaCache: gDirtyAreaCache,

                   newElementCount: gNewElementCount };

     LOG("Saving state.");

     let serialized = JSON.stringify(state, this.serializerHelper);

     LOG("State saved as: " + serialized);

     Services.prefs.setCharPref(kPrefCustomizationState, serialized);

     gDirty = false;

   },

   serializerHelper: function(aKey, aValue) {

     if (typeof aValue == "object" && aValue.constructor.name == "Map") {

       let result = {};

       for (let [mapKey, mapValue] of aValue)

         result[mapKey] = mapValue;

       return result;

     }

     if (typeof aValue == "object" && aValue.constructor.name == "Set") {

       return [...aValue];

     }

     return aValue;

   },

   beginBatchUpdate: function() {

     gInBatchStack++;

   },

   endBatchUpdate: function(aForceDirty) {

     gInBatchStack--;

     if (aForceDirty === true) {

       gDirty = true;

     }

     if (gInBatchStack == 0) {

       this.saveState();

     } else if (gInBatchStack < 0) {

       throw new Error("The batch editing stack should never reach a negative number.");

     }

   },

   addListener: function(aListener) {

     gListeners.add(aListener);

   },

   removeListener: function(aListener) {

     if (aListener == this) {

       return;

     }

     gListeners.delete(aListener);

   },

   notifyListeners: function(aEvent, ...aArgs) {

     if (gRestoring) {

       return;

     }

     for (let listener of gListeners) {

       try {

         if (typeof listener[aEvent] == "function") {

           listener[aEvent].apply(listener, aArgs);

         }

       } catch (e) {

         ERROR(e + " -- " + e.fileName + ":" + e.lineNumber);

       }

     }

   },

   _dispatchToolboxEventToWindow: function(aEventType, aDetails, aWindow) {

     let evt = new aWindow.CustomEvent(aEventType, {

       bubbles: true,

       cancelable: true,

       detail: aDetails

     });

     aWindow.gNavToolbox.dispatchEvent(evt);

   },

   dispatchToolboxEvent: function(aEventType, aDetails={}, aWindow=null) {

     if (aWindow) {

       return this._dispatchToolboxEventToWindow(aEventType, aDetails, aWindow);

     }

     for (let [win, ] of gBuildWindows) {

       this._dispatchToolboxEventToWindow(aEventType, aDetails, win);

     }

   },

   createWidget: function(aProperties) {

     let widget = this.normalizeWidget(aProperties, CustomizableUI.SOURCE_EXTERNAL);

     //XXXunf This should probably throw.

     if (!widget) {

       return;

     }

     gPalette.set(widget.id, widget);

     // Clear our caches:

     gGroupWrapperCache.delete(widget.id);

     for (let [win, ] of gBuildWindows) {

       let cache = gSingleWrapperCache.get(win);

       if (cache) {

         cache.delete(widget.id);

       }

     }

     this.notifyListeners("onWidgetCreated", widget.id);

     if (widget.defaultArea) {

       let area = gAreas.get(widget.defaultArea);

       //XXXgijs this won't have any effect for legacy items. Sort of OK because

       // consumers can modify currentset? Maybe?

       if (area.has("defaultPlacements")) {

         area.get("defaultPlacements").push(widget.id);

       } else {

         area.set("defaultPlacements", [widget.id]);

       }

     }

     // Look through previously saved state to see if we're restoring a widget.

     let seenAreas = new Set();

     let widgetMightNeedAutoAdding = true;

     for (let [area, placements] of gPlacements) {

       seenAreas.add(area);

       let areaIsRegistered = gAreas.has(area);

       let index = gPlacements.get(area).indexOf(widget.id);

       if (index != -1) {

         widgetMightNeedAutoAdding = false;

         if (areaIsRegistered) {

           widget.currentArea = area;

           widget.currentPosition = index;

         }

         break;

       }

     }

     // Also look at saved state data directly in areas that haven't yet been

     // restored. Can't rely on this for restored areas, as they may have

     // changed.

     if (widgetMightNeedAutoAdding && gSavedState) {

       for (let area of Object.keys(gSavedState.placements)) {

         if (seenAreas.has(area)) {

           continue;

         }

         let areaIsRegistered = gAreas.has(area);

         let index = gSavedState.placements[area].indexOf(widget.id);

         if (index != -1) {

           widgetMightNeedAutoAdding = false;

           if (areaIsRegistered) {

             widget.currentArea = area;

             widget.currentPosition = index;

           }

           break;

         }

       }

     }

     // If we're restoring the widget to it's old placement, fire off the

     // onWidgetAdded event - our own handler will take care of adding it to

     // any build areas.

     if (widget.currentArea) {

       this.notifyListeners("onWidgetAdded", widget.id, widget.currentArea,

                            widget.currentPosition);

     } else if (widgetMightNeedAutoAdding) {

       let autoAdd = true;

       try {

         autoAdd = Services.prefs.getBoolPref(kPrefCustomizationAutoAdd);

       } catch (e) {}

       // If the widget doesn't have an existing placement, and it hasn't been

       // seen before, then add it to its default area so it can be used.

       // If the widget is not removable, we *have* to add it to its default

       // area here.

       let canBeAutoAdded = autoAdd && !gSeenWidgets.has(widget.id);

       if (!widget.currentArea && (!widget.removable || canBeAutoAdded)) {

         this.beginBatchUpdate();

         try {

           gSeenWidgets.add(widget.id);

           if (widget.defaultArea) {

             if (this.isAreaLazy(widget.defaultArea)) {

               gFuturePlacements.get(widget.defaultArea).add(widget.id);

             } else {

               this.addWidgetToArea(widget.id, widget.defaultArea);

             }

           }

         } finally {

           this.endBatchUpdate(true);

         }

       }

     }

     this.notifyListeners("onWidgetAfterCreation", widget.id, widget.currentArea);

     return widget.id;

   },

   createBuiltinWidget: function(aData) {

     // This should only ever be called on startup, before any windows are

     // opened - so we know there's no build areas to handle. Also, builtin

     // widgets are expected to be (mostly) static, so shouldn't affect the

     // current placement settings.

     let widget = this.normalizeWidget(aData, CustomizableUI.SOURCE_BUILTIN);

     if (!widget) {

       ERROR("Error creating builtin widget: " + aData.id);

       return;

     }

     LOG("Creating built-in widget with id: " + widget.id);

     gPalette.set(widget.id, widget);

   },

   // Returns true if the area will eventually lazily restore (but hasn't yet).

   isAreaLazy: function(aArea) {

     if (gPlacements.has(aArea)) {

       return false;

     }

     return gAreas.get(aArea).has("legacy");

   },

   //XXXunf Log some warnings here, when the data provided isn't up to scratch.

   normalizeWidget: function(aData, aSource) {

     let widget = {

       implementation: aData,

       source: aSource || "addon",

       instances: new Map(),

       currentArea: null,

       removable: true,

       overflows: true,

       defaultArea: null,

       shortcutId: null,

       tooltiptext: null,

       showInPrivateBrowsing: true,

     };

     if (typeof aData.id != "string" || !/^[a-z0-9-_]{1,}$/i.test(aData.id)) {

       ERROR("Given an illegal id in normalizeWidget: " + aData.id);

       return null;

     }

     delete widget.implementation.currentArea;

     widget.implementation.__defineGetter__("currentArea", function() widget.currentArea);

     const kReqStringProps = ["id"];

     for (let prop of kReqStringProps) {

       if (typeof aData[prop] != "string") {

         ERROR("Missing required property '" + prop + "' in normalizeWidget: "

               + aData.id);

         return null;

       }

       widget[prop] = aData[prop];

     }

     const kOptStringProps = ["label", "tooltiptext", "shortcutId"];

     for (let prop of kOptStringProps) {

       if (typeof aData[prop] == "string") {

         widget[prop] = aData[prop];

       }

     }

     const kOptBoolProps = ["removable", "showInPrivateBrowsing", "overflows"];

     for (let prop of kOptBoolProps) {

       if (typeof aData[prop] == "boolean") {

         widget[prop] = aData[prop];

       }

     }

     if (aData.defaultArea && gAreas.has(aData.defaultArea)) {

       widget.defaultArea = aData.defaultArea;

     } else if (!widget.removable) {

       ERROR("Widget '" + widget.id + "' is not removable but does not specify " +

             "a valid defaultArea. That's not possible; it must specify a " +

             "valid defaultArea as well.");

       return null;

     }

     if ("type" in aData && gSupportedWidgetTypes.has(aData.type)) {

       widget.type = aData.type;

     } else {

       widget.type = "button";

     }

     widget.disabled = aData.disabled === true;

     this.wrapWidgetEventHandler("onBeforeCreated", widget);

     this.wrapWidgetEventHandler("onClick", widget);

     this.wrapWidgetEventHandler("onCreated", widget);

     if (widget.type == "button") {

       widget.onCommand = typeof aData.onCommand == "function" ?

                            aData.onCommand :

                            null;

     } else if (widget.type == "view") {

       if (typeof aData.viewId != "string") {

         ERROR("Expected a string for widget " + widget.id + " viewId, but got "

               + aData.viewId);

         return null;

       }

       widget.viewId = aData.viewId;

       this.wrapWidgetEventHandler("onViewShowing", widget);

       this.wrapWidgetEventHandler("onViewHiding", widget);

     } else if (widget.type == "custom") {

       this.wrapWidgetEventHandler("onBuild", widget);

     }

     if (gPalette.has(widget.id)) {

       return null;

     }

     return widget;

   },

   wrapWidgetEventHandler: function(aEventName, aWidget) {

     if (typeof aWidget.implementation[aEventName] != "function") {

       aWidget[aEventName] = null;

       return;

     }

     aWidget[aEventName] = function(...aArgs) {

       // Wrap inside a try...catch to properly log errors, until bug 862627 is

       // fixed, which in turn might help bug 503244.

       try {

         // Don't copy the function to the normalized widget object, instead

         // keep it on the original object provided to the API so that

         // additional methods can be implemented and used by the event

         // handlers.

         return aWidget.implementation[aEventName].apply(aWidget.implementation,

                                                         aArgs);

       } catch (e) {

         Cu.reportError(e);

       }

     };

   },

   destroyWidget: function(aWidgetId) {

     let widget = gPalette.get(aWidgetId);

     if (!widget) {

       gGroupWrapperCache.delete(aWidgetId);

       for (let [window, ] of gBuildWindows) {

         let windowCache = gSingleWrapperCache.get(window);

         if (windowCache) {

           windowCache.delete(aWidgetId);

         }

       }

       return;

     }

     // Remove it from the default placements of an area if it was added there:

     if (widget.defaultArea) {

       let area = gAreas.get(widget.defaultArea);

       if (area) {

         let defaultPlacements = area.get("defaultPlacements");

         // We can assume this is present because if a widget has a defaultArea,

         // we automatically create a defaultPlacements array for that area.

         let widgetIndex = defaultPlacements.indexOf(aWidgetId);

         if (widgetIndex != -1) {

           defaultPlacements.splice(widgetIndex, 1);

         }

       }

     }

     // This will not remove the widget from gPlacements - we want to keep the

     // setting so the widget gets put back in it's old position if/when it

     // returns.

     for (let [window, ] of gBuildWindows) {

       let windowCache = gSingleWrapperCache.get(window);

       if (windowCache) {

         windowCache.delete(aWidgetId);

       }

       let widgetNode = window.document.getElementById(aWidgetId) ||

                        window.gNavToolbox.palette.getElementsByAttribute("id", aWidgetId)[0];

       if (widgetNode) {

         let container = widgetNode.parentNode

         this.notifyListeners("onWidgetBeforeDOMChange", widgetNode, null,

                              container, true);

         widgetNode.remove();

         this.notifyListeners("onWidgetAfterDOMChange", widgetNode, null,

                              container, true);

       }

       if (widget.type == "view") {

         let viewNode = window.document.getElementById(widget.viewId);

         if (viewNode) {

           for (let eventName of kSubviewEvents) {

             let handler = "on" + eventName;

             if (typeof widget[handler] == "function") {

               viewNode.removeEventListener(eventName, widget[handler], false);

             }

           }

         }

       }

     }

     gPalette.delete(aWidgetId);

     gGroupWrapperCache.delete(aWidgetId);

     this.notifyListeners("onWidgetDestroyed", aWidgetId);

   },

   getCustomizeTargetForArea: function(aArea, aWindow) {

     let buildAreaNodes = gBuildAreas.get(aArea);

     if (!buildAreaNodes) {

       return null;

     }

     for (let node of buildAreaNodes) {

       if (node.ownerDocument.defaultView === aWindow) {

         return node.customizationTarget ? node.customizationTarget : node;

       }

     }

     return null;

   },

   reset: function() {

     gResetting = true;

     this._resetUIState();

     // Rebuild each registered area (across windows) to reflect the state that

     // was reset above.

     this._rebuildRegisteredAreas();

     gResetting = false;

   },

   _resetUIState: function() {

     try {

       gUIStateBeforeReset.drawInTitlebar = Services.prefs.getBoolPref(kPrefDrawInTitlebar);

       gUIStateBeforeReset.uiCustomizationState = Services.prefs.getCharPref(kPrefCustomizationState);

     } catch(e) { }

     this._resetExtraToolbars();

     Services.prefs.clearUserPref(kPrefCustomizationState);

     Services.prefs.clearUserPref(kPrefDrawInTitlebar);

     LOG("State reset");

     // Reset placements to make restoring default placements possible.

     gPlacements = new Map();

     gDirtyAreaCache = new Set();

     gSeenWidgets = new Set();

     // Clear the saved state to ensure that defaults will be used.

     gSavedState = null;

     // Restore the state for each area to its defaults

     for (let [areaId,] of gAreas) {

       this.restoreStateForArea(areaId);

     }

   },

   _resetExtraToolbars: function(aFilter = null) {

     let firstWindow = true; // Only need to unregister and persist once

     for (let [win, ] of gBuildWindows) {

       let toolbox = win.gNavToolbox;

       for (let child of toolbox.children) {

         let matchesFilter = !aFilter || aFilter == child.id;

         if (child.hasAttribute("customindex") && matchesFilter) {

           let toolbarId = "toolbar" + child.getAttribute("customindex");

           toolbox.toolbarset.removeAttribute(toolbarId);

           if (firstWindow) {

             win.document.persist(toolbox.toolbarset.id, toolbarId);

             // We have to unregister it properly to ensure we don't kill

             // XUL widgets which might be in here

             this.unregisterArea(child.id, true);

           }

           child.remove();

         }

       }

       firstWindow = false;

     }

   },

   _rebuildRegisteredAreas: function() {

     for (let [areaId, areaNodes] of gBuildAreas) {

       let placements = gPlacements.get(areaId);

       let isFirstChangedToolbar = true;

       for (let areaNode of areaNodes) {

         this.buildArea(areaId, placements, areaNode);

         let area = gAreas.get(areaId);

         if (area.get("type") == CustomizableUI.TYPE_TOOLBAR) {

           let defaultCollapsed = area.get("defaultCollapsed");

           let win = areaNode.ownerDocument.defaultView;

           if (defaultCollapsed !== null) {

             win.setToolbarVisibility(areaNode, !defaultCollapsed, isFirstChangedToolbar);

           }

         }

         isFirstChangedToolbar = false;

       }

     }

   },

   /**

    * Undoes a previous reset, restoring the state of the UI to the state prior to the reset.

    */

   undoReset: function() {

     if (gUIStateBeforeReset.uiCustomizationState == null ||

         gUIStateBeforeReset.drawInTitlebar == null) {

       return;

     }

     gUndoResetting = true;

     let uiCustomizationState = gUIStateBeforeReset.uiCustomizationState;

     let drawInTitlebar = gUIStateBeforeReset.drawInTitlebar;

     // Need to clear the previous state before setting the prefs

     // because pref observers may check if there is a previous UI state.

     this._clearPreviousUIState();

     Services.prefs.setCharPref(kPrefCustomizationState, uiCustomizationState);

     Services.prefs.setBoolPref(kPrefDrawInTitlebar, drawInTitlebar);

     this.loadSavedState();

     // If the user just customizes toolbar/titlebar visibility, gSavedState will be null

     // and we don't need to do anything else here:

     if (gSavedState) {

       for (let areaId of Object.keys(gSavedState.placements)) {

         let placements = gSavedState.placements[areaId];

         gPlacements.set(areaId, placements);

       }

       this._rebuildRegisteredAreas();

     }

     gUndoResetting = false;

   },

   _clearPreviousUIState: function() {

     Object.getOwnPropertyNames(gUIStateBeforeReset).forEach((prop) => {

       gUIStateBeforeReset[prop] = null;

     });

   },

   removeExtraToolbar: function(aToolbarId) {

     this._resetExtraToolbars(aToolbarId);

   },

   /**

    * @param {String|Node} aWidget - widget ID or a widget node (preferred for performance).

    * @return {Boolean} whether the widget is removable

    */

   isWidgetRemovable: function(aWidget) {

     let widgetId;

     let widgetNode;

     if (typeof aWidget == "string") {

       widgetId = aWidget;

     } else {

       widgetId = aWidget.id;

       widgetNode = aWidget;

     }

     let provider = this.getWidgetProvider(widgetId);

     if (provider == CustomizableUI.PROVIDER_API) {

       return gPalette.get(widgetId).removable;

     }

     if (provider == CustomizableUI.PROVIDER_XUL) {

       if (gBuildWindows.size == 0) {

         // We don't have any build windows to look at, so just assume for now

         // that its removable.

         return true;

       }

       if (!widgetNode) {

         // Pick any of the build windows to look at.

         let [window,] = [...gBuildWindows][0];

         [, widgetNode] = this.getWidgetNode(widgetId, window);

       }

       // If we don't have a node, we assume it's removable. This can happen because

       // getWidgetProvider returns PROVIDER_XUL by default, but this will also happen

       // for API-provided widgets which have been destroyed.

       if (!widgetNode) {

         return true;

       }

       return widgetNode.getAttribute("removable") == "true";

     }

     // Otherwise this is either a special widget, which is always removable, or

     // an API widget which has already been removed from gPalette. Returning true

     // here allows us to then remove its ID from any placements where it might

     // still occur.

     return true;

   },

   canWidgetMoveToArea: function(aWidgetId, aArea) {

     let placement = this.getPlacementOfWidget(aWidgetId);

     if (placement && placement.area != aArea) {

       // Special widgets can't move to the menu panel.

       if (this.isSpecialWidget(aWidgetId) && gAreas.has(aArea) &&

           gAreas.get(aArea).get("type") == CustomizableUI.TYPE_MENU_PANEL) {

         return false;

       }

       // For everything else, just return whether the widget is removable.

       return this.isWidgetRemovable(aWidgetId);

     }

     return true;

   },

   ensureWidgetPlacedInWindow: function(aWidgetId, aWindow) {

     let placement = this.getPlacementOfWidget(aWidgetId);

     if (!placement) {

       return false;

     }

     let areaNodes = gBuildAreas.get(placement.area);

     if (!areaNodes) {

       return false;

     }

     let container = [...areaNodes].filter((n) => n.ownerDocument.defaultView == aWindow);

     if (!container.length) {

       return false;

     }

     let existingNode = container[0].getElementsByAttribute("id", aWidgetId)[0];

     if (existingNode) {

       return true;

     }

     this.insertNodeInWindow(aWidgetId, container[0], true);

     return true;

   },

   get inDefaultState() {

     for (let [areaId, props] of gAreas) {

       let defaultPlacements = props.get("defaultPlacements");

       // Areas without default placements (like legacy ones?) get skipped

       if (!defaultPlacements) {

         continue;

       }

       let currentPlacements = gPlacements.get(areaId);

       // We're excluding all of the placement IDs for items that do not exist,

       // and items that have removable="false",

       // because we don't want to consider them when determining if we're

       // in the default state. This way, if an add-on introduces a widget

       // and is then uninstalled, the leftover placement doesn't cause us to

       // automatically assume that the buttons are not in the default state.

       let buildAreaNodes = gBuildAreas.get(areaId);

       if (buildAreaNodes && buildAreaNodes.size) {

         let container = [...buildAreaNodes][0];

         let removableOrDefault = (itemNodeOrItem) => {

           let item = (itemNodeOrItem && itemNodeOrItem.id) || itemNodeOrItem;

           let isRemovable = this.isWidgetRemovable(itemNodeOrItem);

           let isInDefault = defaultPlacements.indexOf(item) != -1;

           return isRemovable || isInDefault;

         };

         // Toolbars have a currentSet property which also deals correctly with overflown

         // widgets (if any) - use that instead:

         if (props.get("type") == CustomizableUI.TYPE_TOOLBAR) {

           let currentSet = container.currentSet;

           currentPlacements = currentSet ? currentSet.split(',') : [];

           currentPlacements = currentPlacements.filter(removableOrDefault);

         } else {

           // Clone the array so we don't modify the actual placements...

           currentPlacements = [...currentPlacements];

           currentPlacements = currentPlacements.filter((item) => {

             let itemNode = container.getElementsByAttribute("id", item)[0];

             return itemNode && removableOrDefault(itemNode || item);

           });

         }

         if (props.get("type") == CustomizableUI.TYPE_TOOLBAR) {

           let attribute = container.getAttribute("type") == "menubar" ? "autohide" : "collapsed";

           let collapsed = container.getAttribute(attribute) == "true";

           let defaultCollapsed = props.get("defaultCollapsed");

           if (defaultCollapsed !== null && collapsed != defaultCollapsed) {

             LOG("Found " + areaId + " had non-default toolbar visibility (expected " + defaultCollapsed + ", was " + collapsed + ")");

             return false;

           }

         }

       }

       LOG("Checking default state for " + areaId + ":\n" + currentPlacements.join(",") +

           "\nvs.\n" + defaultPlacements.join(","));

       if (currentPlacements.length != defaultPlacements.length) {

         return false;

       }

       for (let i = 0; i < currentPlacements.length; ++i) {

         if (currentPlacements[i] != defaultPlacements[i]) {

           LOG("Found " + currentPlacements[i] + " in " + areaId + " where " +

               defaultPlacements[i] + " was expected!");

           return false;

         }

       }

     }

     if (Services.prefs.prefHasUserValue(kPrefDrawInTitlebar)) {

       LOG(kPrefDrawInTitlebar + " pref is non-default");

       return false;

     }

     return true;

   },

   setToolbarVisibility: function(aToolbarId, aIsVisible) {

     // We only persist the attribute the first time.

     let isFirstChangedToolbar = true;

     for (let window of CustomizableUI.windows) {

       let toolbar = window.document.getElementById(aToolbarId);

       if (toolbar) {

         window.setToolbarVisibility(toolbar, aIsVisible, isFirstChangedToolbar);

         isFirstChangedToolbar = false;

       }

     }

   },

 };

 Object.freeze(CustomizableUIInternal);

 this.CustomizableUI = {

   /**

    * Constant reference to the ID of the menu panel.

    */

   get AREA_PANEL() "PanelUI-contents",

   /**

    * Constant reference to the ID of the navigation toolbar.

    */

   get AREA_NAVBAR() "nav-bar",

   /**

    * Constant reference to the ID of the menubar's toolbar.

    */

   get AREA_MENUBAR() "toolbar-menubar",

   /**

    * Constant reference to the ID of the tabstrip toolbar.

    */

   get AREA_TABSTRIP() "TabsToolbar",

   /**

    * Constant reference to the ID of the bookmarks toolbar.

    */

   get AREA_BOOKMARKS() "PersonalToolbar",

   /**

    * Constant reference to the ID of the addon-bar toolbar shim.

    * Do not use, this will be removed as soon as reasonably possible.

    * @deprecated

    */

   get AREA_ADDONBAR() "addon-bar",

   /**

    * Constant indicating the area is a menu panel.

    */

   get TYPE_MENU_PANEL() "menu-panel",

   /**

    * Constant indicating the area is a toolbar.

    */

   get TYPE_TOOLBAR() "toolbar",

   /**

    * Constant indicating a XUL-type provider.

    */

   get PROVIDER_XUL() "xul",

   /**

    * Constant indicating an API-type provider.

    */

   get PROVIDER_API() "api",

   /**

    * Constant indicating dynamic (special) widgets: spring, spacer, and separator.

    */

   get PROVIDER_SPECIAL() "special",

   /**

    * Constant indicating the widget is built-in

    */

   get SOURCE_BUILTIN() "builtin",

   /**

    * Constant indicating the widget is externally provided

    * (e.g. by add-ons or other items not part of the builtin widget set).

    */

   get SOURCE_EXTERNAL() "external",

   /**

    * The class used to distinguish items that span the entire menu panel.

    */

   get WIDE_PANEL_CLASS() "panel-wide-item",

   /**

    * The (constant) number of columns in the menu panel.

    */

   get PANEL_COLUMN_COUNT() 3,

   /**

    * Constant indicating the reason the event was fired was a window closing

    */

   get REASON_WINDOW_CLOSED() "window-closed",

   /**

    * Constant indicating the reason the event was fired was an area being

    * unregistered separately from window closing mechanics.

    */

   get REASON_AREA_UNREGISTERED() "area-unregistered",

   /**

    * An iteratable property of windows managed by CustomizableUI.

    * Note that this can *only* be used as an iterator. ie:

    *     for (let window of CustomizableUI.windows) { ... }

    */

   windows: {

     "@@iterator": function*() {

       for (let [window,] of gBuildWindows)

         yield window;

     }

   },

   /**

    * Add a listener object that will get fired for various events regarding

    * customization.

    *

    * @param aListener the listener object to add

    *

    * Not all event handler methods need to be defined.

    * CustomizableUI will catch exceptions. Events are dispatched

    * synchronously on the UI thread, so if you can delay any/some of your

    * processing, that is advisable. The following event handlers are supported:

    *   - onWidgetAdded(aWidgetId, aArea, aPosition)

    *     Fired when a widget is added to an area. aWidgetId is the widget that

    *     was added, aArea the area it was added to, and aPosition the position

    *     in which it was added.

    *   - onWidgetMoved(aWidgetId, aArea, aOldPosition, aNewPosition)

    *     Fired when a widget is moved within its area. aWidgetId is the widget

    *     that was moved, aArea the area it was moved in, aOldPosition its old

    *     position, and aNewPosition its new position.

    *   - onWidgetRemoved(aWidgetId, aArea)

    *     Fired when a widget is removed from its area. aWidgetId is the widget

    *     that was removed, aArea the area it was removed from.

    *

    *   - onWidgetBeforeDOMChange(aNode, aNextNode, aContainer, aIsRemoval)

    *     Fired *before* a widget's DOM node is acted upon by CustomizableUI

    *     (to add, move or remove it). aNode is the DOM node changed, aNextNode

    *     the DOM node (if any) before which a widget will be inserted,

    *     aContainer the *actual* DOM container (could be an overflow panel in

    *     case of an overflowable toolbar), and aWasRemoval is true iff the

    *     action about to happen is the removal of the DOM node.

    *   - onWidgetAfterDOMChange(aNode, aNextNode, aContainer, aWasRemoval)

    *     Like onWidgetBeforeDOMChange, but fired after the change to the DOM

    *     node of the widget.

    *

    *   - onWidgetReset(aNode, aContainer)

    *     Fired after a reset to default placements moves a widget's node to a

    *     different location. aNode is the widget's node, aContainer is the

    *     area it was moved into (NB: it might already have been there and been

    *     moved to a different position!)

    *   - onWidgetUndoMove(aNode, aContainer)

    *     Fired after undoing a reset to default placements moves a widget's

    *     node to a different location. aNode is the widget's node, aContainer

    *     is the area it was moved into (NB: it might already have been there

    *     and been moved to a different position!)

    *   - onAreaReset(aArea, aContainer)

    *     Fired after a reset to default placements is complete on an area's

    *     DOM node. Note that this is fired for each DOM node. aArea is the area

    *     that was reset, aContainer the DOM node that was reset.

    *

    *   - onWidgetCreated(aWidgetId)

    *     Fired when a widget with id aWidgetId has been created, but before it

    *     is added to any placements or any DOM nodes have been constructed.

    *     Only fired for API-based widgets.

    *   - onWidgetAfterCreation(aWidgetId, aArea)

    *     Fired after a widget with id aWidgetId has been created, and has been

    *     added to either its default area or the area in which it was placed

    *     previously. If the widget has no default area and/or it has never

    *     been placed anywhere, aArea may be null. Only fired for API-based

    *     widgets.

    *   - onWidgetDestroyed(aWidgetId)

    *     Fired when widgets are destroyed. aWidgetId is the widget that is

    *     being destroyed. Only fired for API-based widgets.

    *   - onWidgetInstanceRemoved(aWidgetId, aDocument)

    *     Fired when a window is unloaded and a widget's instance is destroyed

    *     because of this. Only fired for API-based widgets.

    *

    *   - onWidgetDrag(aWidgetId, aArea)

    *     Fired both when and after customize mode drag handling system tries