Issue #303 Part 1: Move basilisk files from /browser to /application/basilisk

15 files changed, 0 insertions, 10796 deletions

diff --git a/browser/components/customizableui/CustomizableUI.jsm b/browser/components/customizableui/CustomizableUI.jsm
deleted file mode 100644
index cb0f519b2..000000000
--- a/browser/components/customizableui/CustomizableUI.jsm
+++ /dev/null
@@ -1,4401 +0,0 @@
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-"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");
-Cu.import("resource://gre/modules/AppConstants.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.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");
-XPCOMUtils.defineLazyModuleGetter(this, "LightweightThemeManager",
-                                  "resource://gre/modules/LightweightThemeManager.jsm");
-
-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";
-const kPrefWebIDEInNavbar            = "devtools.webide.widget.inNavbarByDefault";
-
-const kExpectedWindowURL = "chrome://browser/content/browser.xul";
-
-/**
- * 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"
-];
-
-/**
- * The current version. We can use this to auto-add new default widgets as necessary.
- * (would be const but isn't because of testing purposes)
- */
-var kVersion = 6;
-
-/**
- * Buttons removed from built-ins by version they were removed. kVersion must be
- * bumped any time a new id is added to this. Use the button id as key, and
- * version the button is removed in as the value.  e.g. "pocket-button": 5
- */
-var ObsoleteBuiltinButtons = {
-  "pocket-button": 6
-};
-
-/**
- * gPalette is a map of every widget that CustomizableUI.jsm knows about, keyed
- * on their IDs.
- */
-var 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.
- */
-var 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).
- */
-var 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.
- */
-var gFuturePlacements = new Map();
-
-// XXXunf Temporary. Need a nice way to abstract functions to build widgets
-//       of these types.
-var 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.
- */
-var 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.
- */
-var 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".
- */
-var 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
- */
-var gPendingBuildAreas = new Map();
-
-var gSavedState = null;
-var gRestoring = false;
-var gDirty = false;
-var gInBatchStack = 0;
-var gResetting = false;
-var gUndoResetting = false;
-
-/**
- * gBuildAreas maps area IDs to actual area nodes within browser windows.
- */
-var gBuildAreas = new Map();
-
-/**
- * gBuildWindows is a map of windows that have registered build areas, mapped
- * to a Set of known toolboxes in that window.
- */
-var gBuildWindows = new Map();
-
-var gNewElementCount = 0;
-var gGroupWrapperCache = new Map();
-var gSingleWrapperCache = new WeakMap();
-var gListeners = new Set();
-
-var gUIStateBeforeReset = {
-  uiCustomizationState: null,
-  drawInTitlebar: null,
-  currentTheme: null,
-};
-
-XPCOMUtils.defineLazyGetter(this, "log", () => {
-  let scope = {};
-  Cu.import("resource://gre/modules/Console.jsm", scope);
-  let debug;
-  try {
-    debug = Services.prefs.getBoolPref(kPrefCustomizationDebug);
-  } catch (ex) {}
-  let consoleOptions = {
-    maxLogLevel: debug ? "all" : "log",
-    prefix: "CustomizableUI",
-  };
-  return new scope.ConsoleAPI(consoleOptions);
-});
-
-var CustomizableUIInternal = {
-  initialize: function() {
-    log.debug("Initializing");
-
-    this.addListener(this);
-    this._defineBuiltInWidgets();
-    this.loadSavedState();
-    this._introduceNewBuiltinWidgets();
-    this._markObsoleteBuiltinButtonsSeen();
-
-    /**
-     * Please be advised that adding items to the panel by default could
-     * cause CART talos test regressions. This might happen when the
-     * number of items in the panel causes the area to become "scrollable"
-     * during the last phases of the transition. See bug 1230671 for an
-     * example of this. Be sure that what you're adding really needs to go
-     * into the panel by default, and if it does, consider swapping
-     * something out for it.
-     */
-    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",
-      "sync-button",
-    ];
-
-    if (!AppConstants.MOZ_DEV_EDITION) {
-      panelPlacements.splice(-1, 0, "developer-button");
-    }
-
-    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();
-
-    let navbarPlacements = [
-      "urlbar-container",
-      "search-container",
-      "bookmarks-menu-button",
-      "downloads-button",
-      "home-button",
-    ];
-
-    if (AppConstants.MOZ_DEV_EDITION) {
-      navbarPlacements.splice(2, 0, "developer-button");
-    }
-
-    if (Services.prefs.getBoolPref(kPrefWebIDEInNavbar)) {
-      navbarPlacements.push("webide-button");
-    }
-
-    // Place this last, when createWidget is called for pocket, it will
-    // append to the toolbar.
-    if (Services.prefs.getPrefType("extensions.pocket.enabled") != Services.prefs.PREF_INVALID &&
-        Services.prefs.getBoolPref("extensions.pocket.enabled")) {
-        navbarPlacements.push("pocket-button");
-    }
-
-    this.registerArea(CustomizableUI.AREA_NAVBAR, {
-      legacy: true,
-      type: CustomizableUI.TYPE_TOOLBAR,
-      overflowable: true,
-      defaultPlacements: navbarPlacements,
-      defaultCollapsed: false,
-    }, true);
-
-    if (AppConstants.MENUBAR_CAN_AUTOHIDE) {
-      this.registerArea(CustomizableUI.AREA_MENUBAR, {
-        legacy: true,
-        type: CustomizableUI.TYPE_TOOLBAR,
-        defaultPlacements: [
-          "menubar-items",
-        ],
-        defaultCollapsed: true,
-      }, true);
-    }
-
-    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() {
-    let toolbars = new Set([
-      CustomizableUI.AREA_NAVBAR,
-      CustomizableUI.AREA_BOOKMARKS,
-      CustomizableUI.AREA_TABSTRIP,
-      CustomizableUI.AREA_ADDONBAR,
-    ]);
-    if (AppConstants.platform != "macosx") {
-      toolbars.add(CustomizableUI.AREA_MENUBAR);
-    }
-    return toolbars;
-  },
-
-  _defineBuiltInWidgets: function() {
-    for (let widgetDefinition of CustomizableWidgets) {
-      this.createBuiltinWidget(widgetDefinition);
-    }
-  },
-
-  _introduceNewBuiltinWidgets: function() {
-    // We should still enter even if gSavedState.currentVersion >= kVersion
-    // because the per-widget pref facility is independent of versioning.
-    if (!gSavedState) {
-      // Flip all the prefs so we don't try to re-introduce later:
-      for (let [, widget] of gPalette) {
-        if (widget.defaultArea && widget._introducedInVersion === "pref") {
-          let prefId = "browser.toolbarbuttons.introduced." + widget.id;
-          Services.prefs.setBoolPref(prefId, true);
-        }
-      }
-      return;
-    }
-
-    let currentVersion = gSavedState.currentVersion;
-    for (let [id, widget] of gPalette) {
-      if (widget.defaultArea) {
-        let shouldAdd = false;
-        let shouldSetPref = false;
-        let prefId = "browser.toolbarbuttons.introduced." + widget.id;
-        if (widget._introducedInVersion === "pref") {
-          try {
-            shouldAdd = !Services.prefs.getBoolPref(prefId);
-          } catch (ex) {
-            // Pref doesn't exist:
-            shouldAdd = true;
-          }
-          shouldSetPref = shouldAdd;
-        } else if (widget._introducedInVersion > currentVersion) {
-          shouldAdd = true;
-        }
-
-        if (shouldAdd) {
-          let futurePlacements = gFuturePlacements.get(widget.defaultArea);
-          if (futurePlacements) {
-            futurePlacements.add(id);
-          } else {
-            gFuturePlacements.set(widget.defaultArea, new Set([id]));
-          }
-          if (shouldSetPref) {
-            Services.prefs.setBoolPref(prefId, true);
-          }
-        }
-      }
-    }
-
-    if (currentVersion < 2) {
-      // Nuke the old 'loop-call-button' out of orbit.
-      CustomizableUI.removeWidgetFromArea("loop-call-button");
-    }
-
-    if (currentVersion < 4) {
-      CustomizableUI.removeWidgetFromArea("loop-button-throttled");
-    }
-  },
-
-  /**
-   * _markObsoleteBuiltinButtonsSeen
-   * when upgrading, ensure obsoleted buttons are in seen state.
-   */
-  _markObsoleteBuiltinButtonsSeen: function() {
-    if (!gSavedState)
-      return;
-    let currentVersion = gSavedState.currentVersion;
-    if (currentVersion >= kVersion)
-      return;
-    // we're upgrading, update state if necessary
-    for (let id in ObsoleteBuiltinButtons) {
-      let version = ObsoleteBuiltinButtons[id]
-      if (version == kVersion) {
-        gSeenWidgets.add(id);
-        gDirty = true;
-      }
-    }
-  },
-
-  _placeNewDefaultWidgetsInArea: function(aArea) {
-    let futurePlacedWidgets = gFuturePlacements.get(aArea);
-    let savedPlacements = gSavedState && gSavedState.placements && gSavedState.placements[aArea];
-    let defaultPlacements = gAreas.get(aArea).get("defaultPlacements");
-    if (!savedPlacements || !savedPlacements.length || !futurePlacedWidgets || !defaultPlacements ||
-        !defaultPlacements.length) {
-      return;
-    }
-    let defaultWidgetIndex = -1;
-
-    for (let widgetId of futurePlacedWidgets) {
-      let widget = gPalette.get(widgetId);
-      if (!widget || widget.source !== CustomizableUI.SOURCE_BUILTIN ||
-          !widget.defaultArea || !widget._introducedInVersion ||
-          savedPlacements.indexOf(widget.id) !== -1) {
-        continue;
-      }
-      defaultWidgetIndex = defaultPlacements.indexOf(widget.id);
-      if (defaultWidgetIndex === -1) {
-        continue;
-      }
-      // Now we know that this widget should be here by default, was newly introduced,
-      // and we have a saved state to insert into, and a default state to work off of.
-      // Try introducing after widgets that come before it in the default placements:
-      for (let i = defaultWidgetIndex; i >= 0; i--) {
-        // Special case: if the defaults list this widget as coming first, insert at the beginning:
-        if (i === 0 && i === defaultWidgetIndex) {
-          savedPlacements.splice(0, 0, widget.id);
-          // Before you ask, yes, deleting things inside a let x of y loop where y is a Set is
-          // safe, and we won't skip any items.
-          futurePlacedWidgets.delete(widget.id);
-          gDirty = true;
-          break;
-        }
-        // Otherwise, if we're somewhere other than the beginning, check if the previous
-        // widget is in the saved placements.
-        if (i) {
-          let previousWidget = defaultPlacements[i - 1];
-          let previousWidgetIndex = savedPlacements.indexOf(previousWidget);
-          if (previousWidgetIndex != -1) {
-            savedPlacements.splice(previousWidgetIndex + 1, 0, widget.id);
-            futurePlacedWidgets.delete(widget.id);
-            gDirty = true;
-            break;
-          }
-        }
-      }
-      // The loop above either inserts the item or doesn't - either way, we can get away
-      // with doing nothing else now; if the item remains in gFuturePlacements, we'll
-      // add it at the end in restoreStateForArea.
-    }
-    this.saveState();
-  },
-
-  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);
-
-      // Reconcile new default widgets. Have to do this before we start restoring things.
-      this._placeNewDefaultWidgetsInArea(aName);
-
-      if (props.get("legacy") && !gPlacements.has(aName)) {
-        // Guarantee this area exists in gFuturePlacements, to avoid checking it in
-        // various places elsewhere.
-        if (!gFuturePlacements.has(aName)) {
-          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 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.debug("Unknown widget: " + id);
-          continue;
-        }
-
-        let widget = null;
-        // If the placements have items in them which are (now) no longer removable,
-        // we shouldn't be moving them:
-        if (provider == CustomizableUI.PROVIDER_API) {
-          widget = gPalette.get(id);
-          if (!widget.removable && aArea != widget.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 && widget && !widget.showInPrivateBrowsing) {
-          continue;
-        }
-
-        this.ensureButtonContextMenu(node, aAreaNode);
-        if (node.localName == "toolbarbutton") {
-          if (areaIsPanel) {
-            node.setAttribute("wrap", "true");
-          } else {
-            node.removeAttribute("wrap");
-          }
-        }
-
-        // This needs updating in case we're resetting / undoing a reset.
-        if (widget) {
-          widget.currentArea = aArea;
-        }
-        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 {
-              node.setAttribute("removable", false);
-              log.debug("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.ownerGlobal;
-    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.ownerGlobal;
-    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.debug("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.debug("Searching for " + aWidgetId + " in toolbox.");
-    let node = this.findWidgetInWindow(aWidgetId, aWindow);
-    if (node) {
-      return [ CustomizableUI.PROVIDER_XUL, node ];
-    }
-
-    log.debug("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.ownerGlobal;
-      if (!showInPrivateBrowsing &&
-          PrivateBrowsingUtils.isWindowPrivate(window)) {
-        continue;
-      }
-
-      let container = areaNode.customizationTarget;
-      let widgetNode = window.document.getElementById(aWidgetId);
-      if (widgetNode && isOverflowable) {
-        container = areaNode.overflowable.getContainerFor(widgetNode);
-      }
-
-      if (!widgetNode || !container.contains(widgetNode)) {
-        log.info("Widget " + aWidgetId + " not found, unable to remove from " + aArea);
-        continue;
-      }
-
-      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.ownerGlobal;
-    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 [, areaMap] of gPendingBuildAreas) {
-      let toDelete = [];
-      for (let [areaNode, ] of areaMap) {
-        if (areaNode.ownerDocument == document) {
-          toDelete.push(areaNode);
-        }
-      }
-      for (let areaNode of toDelete) {
-        areaMap.delete(areaNode);
-      }
-    }
-
-    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) {
-      log.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.ownerGlobal;
-    let showInPrivateBrowsing = gPalette.has(aWidgetId)
-                              ? gPalette.get(aWidgetId).showInPrivateBrowsing
-                              : true;
-
-    if (!showInPrivateBrowsing && PrivateBrowsingUtils.isWindowPrivate(window)) {
-      return;
-    }
-
-    let [, widgetNode] = this.getWidgetNode(aWidgetId, window);
-    if (!widgetNode) {
-      log.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) {
-      log.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 (aDocument.documentURI != kExpectedWindowURL) {
-      throw new Error("buildWidget was called for a non-browser window!");
-    }
-    if (typeof aWidget == "string") {
-      aWidget = gPalette.get(aWidget);
-    }
-    if (!aWidget) {
-      throw new Error("buildWidget was passed a non-widget to build.");
-    }
-
-    log.debug("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))
-        log.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);
-      if (aWidget.tabSpecific) {
-        node.setAttribute("tabspecific", aWidget.tabSpecific);
-      }
-      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 {
-          log.error("Key element with id '" + aWidget.shortcutId + "' for widget '" + aWidget.id +
-                    "' not found!");
-        }
-      }
-
-      let tooltip = this.getLocalizedProperty(aWidget, "tooltiptext", additionalTooltipArguments);
-      if (tooltip) {
-        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.debug("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.debug("Widget " + aWidget.id + " showing and hiding event handlers set.");
-        } else {
-          log.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) {
-    const kReqStringProps = ["label"];
-
-    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] != null) {
-      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 an empty string was explicitly passed, treat it as an actual
-      // value rather than a missing property.
-      if (!def && (name != "" || kReqStringProps.includes(aProp))) {
-        log.error("Could not localize property '" + name + "'.");
-      }
-    }
-    return def;
-  },
-
-  addShortcut: function(aShortcutNode, aTargetNode) {
-    if (!aTargetNode)
-      aTargetNode = aShortcutNode;
-    let document = aShortcutNode.ownerDocument;
-
-    // Detect if we've already been here before.
-    if (!aTargetNode || aTargetNode.hasAttribute("shortcut"))
-      return;
-
-    let shortcutId = aShortcutNode.getAttribute("key");
-    let shortcut;
-    if (shortcutId) {
-      shortcut = document.getElementById(shortcutId);
-    } else {
-      let commandId = aShortcutNode.getAttribute("command");
-      if (commandId)
-        shortcut = ShortcutUtils.findShortcut(document.getElementById(commandId));
-    }
-    if (!shortcut) {
-      return;
-    }
-
-    aTargetNode.setAttribute("shortcut", ShortcutUtils.prettifyShortcut(shortcut));
-  },
-
-  handleWidgetCommand: function(aWidget, aNode, aEvent) {
-    log.debug("handleWidgetCommand");
-
-    if (aWidget.type == "button") {
-      if (aWidget.onCommand) {
-        try {
-          aWidget.onCommand.call(null, aEvent);
-        } catch (e) {
-          log.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.ownerGlobal;
-      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.debug("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) {
-      // Skip out of iframes etc:
-      if (target.nodeType == target.DOCUMENT_NODE) {
-        if (!target.defaultView) {
-          // Err, we're done.
-          break;
-        }
-        // Cue some voodoo
-        target = target.defaultView.QueryInterface(Ci.nsIInterfaceRequestor)
-                                   .getInterface(Ci.nsIWebNavigation)
-                                   .QueryInterface(Ci.nsIDocShell)
-                                   .chromeEventHandler;
-        if (!target) {
-          break;
-        }
-      }
-      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";
-      }
-      // Break out of the loop immediately for disabled items, as we need to
-      // keep the menu open in that case.
-      if (target.getAttribute("disabled") == "true") {
-        return true;
-      }
-
-      // 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.debug("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.ownerGlobal;
-    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.debug("Iterating the actual nodes of the window palette");
-    for (let node of aWindowPalette.children) {
-      log.debug("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.debug("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.debug("Error loading saved UI customization state, falling back to defaults.");
-    }
-
-    if (!("placements" in gSavedState)) {
-      gSavedState.placements = {};
-    }
-
-    if (!("currentVersion" in gSavedState)) {
-      gSavedState.currentVersion = 0;
-    }
-
-    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.debug("Restoring " + aArea + " from pre-existing placements");
-        for (let [position, id] of gPlacements.get(aArea).entries()) {
-          this.moveWidgetWithinArea(id, position);
-        }
-        gDirty = false;
-        restored = true;
-      } else {
-        gPlacements.set(aArea, []);
-      }
-
-      if (!restored && gSavedState && aArea in gSavedState.placements) {
-        log.debug("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.debug("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.debug("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);
-        gFuturePlacements.delete(aArea);
-      }
-
-      log.debug("Placements for " + aArea + ":\n\t" + gPlacements.get(aArea).join("\n\t"));
-
-      gRestoring = false;
-    } finally {
-      this.endBatchUpdate();
-    }
-  },
-
-  saveState: function() {
-    if (gInBatchStack || !gDirty) {
-      return;
-    }
-    // Clone because we want to modify this map:
-    let state = { placements: new Map(gPlacements),
-                  seen: gSeenWidgets,
-                  dirtyAreaCache: gDirtyAreaCache,
-                  currentVersion: kVersion,
-                  newElementCount: gNewElementCount };
-
-    // Merge in previously saved areas if not present in gPlacements.
-    // This way, state is still persisted for e.g. temporarily disabled
-    // add-ons - see bug 989338.
-    if (gSavedState && gSavedState.placements) {
-      for (let area of Object.keys(gSavedState.placements)) {
-        if (!state.placements.has(area)) {
-          let placements = gSavedState.placements[area];
-          state.placements.set(area, placements);
-        }
-      }
-    }
-
-    log.debug("Saving state.");
-    let serialized = JSON.stringify(state, this.serializerHelper);
-    log.debug("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) {
-        log.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) {
-      this._dispatchToolboxEventToWindow(aEventType, aDetails, aWindow);
-      return;
-    }
-    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) {
-      log.error("unable to normalize widget");
-      return undefined;
-    }
-
-    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 addToDefaultPlacements = false;
-      let area = gAreas.get(widget.defaultArea);
-      if (!CustomizableUI.isBuiltinToolbar(widget.defaultArea) &&
-          widget.defaultArea != CustomizableUI.AREA_PANEL) {
-        addToDefaultPlacements = true;
-      }
-
-      if (addToDefaultPlacements) {
-        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, ] 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.
-    this.beginBatchUpdate();
-    try {
-      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)) {
-          if (widget.defaultArea) {
-            if (this.isAreaLazy(widget.defaultArea)) {
-              gFuturePlacements.get(widget.defaultArea).add(widget.id);
-            } else {
-              this.addWidgetToArea(widget.id, widget.defaultArea);
-            }
-          }
-        }
-      }
-    } finally {
-      // Ensure we always have this widget in gSeenWidgets, and save
-      // state in case this needs to be done here.
-      gSeenWidgets.add(widget.id);
-      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.
-
-    // This allows a widget to be both built-in by default but also able to be
-    // destroyed and removed from the area based on criteria that may not be
-    // available when the widget is created -- for example, because some other
-    // feature in the browser supersedes the widget.
-    let conditionalDestroyPromise = aData.conditionalDestroyPromise || null;
-    delete aData.conditionalDestroyPromise;
-
-    let widget = this.normalizeWidget(aData, CustomizableUI.SOURCE_BUILTIN);
-    if (!widget) {
-      log.error("Error creating builtin widget: " + aData.id);
-      return;
-    }
-
-    log.debug("Creating built-in widget with id: " + widget.id);
-    gPalette.set(widget.id, widget);
-
-    if (conditionalDestroyPromise) {
-      conditionalDestroyPromise.then(shouldDestroy => {
-        if (shouldDestroy) {
-          this.destroyWidget(widget.id);
-          this.removeWidgetFromArea(widget.id);
-        }
-      }, err => {
-        Cu.reportError(err);
-      });
-    }
-  },
-
-  // 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 || CustomizableUI.SOURCE_EXTERNAL,
-      instances: new Map(),
-      currentArea: null,
-      removable: true,
-      overflows: true,
-      defaultArea: null,
-      shortcutId: null,
-      tabSpecific: false,
-      tooltiptext: null,
-      showInPrivateBrowsing: true,
-      _introducedInVersion: -1,
-    };
-
-    if (typeof aData.id != "string" || !/^[a-z0-9-_]{1,}$/i.test(aData.id)) {
-      log.error("Given an illegal id in normalizeWidget: " + aData.id);
-      return null;
-    }
-
-    delete widget.implementation.currentArea;
-    widget.implementation.__defineGetter__("currentArea", () => widget.currentArea);
-
-    const kReqStringProps = ["id"];
-    for (let prop of kReqStringProps) {
-      if (typeof aData[prop] != "string") {
-        log.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", "tabSpecific"];
-    for (let prop of kOptBoolProps) {
-      if (typeof aData[prop] == "boolean") {
-        widget[prop] = aData[prop];
-      }
-    }
-
-    // When we normalize builtin widgets, areas have not yet been registered:
-    if (aData.defaultArea &&
-        (aSource == CustomizableUI.SOURCE_BUILTIN || gAreas.has(aData.defaultArea))) {
-      widget.defaultArea = aData.defaultArea;
-    } else if (!widget.removable) {
-      log.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;
-
-    if (aSource == CustomizableUI.SOURCE_BUILTIN) {
-      widget._introducedInVersion = aData.introducedInVersion || 0;
-    }
-
-    this.wrapWidgetEventHandler("onBeforeCreated", widget);
-    this.wrapWidgetEventHandler("onClick", widget);
-    this.wrapWidgetEventHandler("onCreated", widget);
-    this.wrapWidgetEventHandler("onDestroyed", widget);
-
-    if (widget.type == "button") {
-      widget.onCommand = typeof aData.onCommand == "function" ?
-                           aData.onCommand :
-                           null;
-    } else if (widget.type == "view") {
-      if (typeof aData.viewId != "string") {
-        log.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);
-        return undefined;
-      }
-    };
-  },
-
-  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);
-            }
-          }
-        }
-      }
-      if (widgetNode && widget.onDestroyed) {
-        widget.onDestroyed(window.document);
-      }
-    }
-
-    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.ownerGlobal == 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();
-
-    for (let [widgetId, widget] of gPalette) {
-      if (widget.source == CustomizableUI.SOURCE_EXTERNAL) {
-        gSeenWidgets.add(widgetId);
-      }
-    }
-    if (gSeenWidgets.size) {
-      gDirty = true;
-    }
-
-    gResetting = false;
-  },
-
-  _resetUIState: function() {
-    try {
-      gUIStateBeforeReset.drawInTitlebar = Services.prefs.getBoolPref(kPrefDrawInTitlebar);
-      gUIStateBeforeReset.uiCustomizationState = Services.prefs.getCharPref(kPrefCustomizationState);
-      gUIStateBeforeReset.currentTheme = LightweightThemeManager.currentTheme;
-    } catch (e) { }
-
-    this._resetExtraToolbars();
-
-    Services.prefs.clearUserPref(kPrefCustomizationState);
-    Services.prefs.clearUserPref(kPrefDrawInTitlebar);
-    LightweightThemeManager.currentTheme = null;
-    log.debug("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.ownerGlobal;
-          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;
-    let currentTheme = gUIStateBeforeReset.currentTheme;
-
-    // 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);
-    LightweightThemeManager.currentTheme = currentTheme;
-    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.ownerGlobal == 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.debug("Found " + areaId + " had non-default toolbar visibility (expected " + defaultCollapsed + ", was " + collapsed + ")");
-            return false;
-          }
-        }
-      }
-      log.debug("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.debug("Found " + currentPlacements[i] + " in " + areaId + " where " +
-                    defaultPlacements[i] + " was expected!");
-          return false;
-        }
-      }
-    }
-
-    if (Services.prefs.prefHasUserValue(kPrefDrawInTitlebar)) {
-      log.debug(kPrefDrawInTitlebar + " pref is non-default");
-      return false;
-    }
-
-    if (LightweightThemeManager.currentTheme) {
-      log.debug(LightweightThemeManager.currentTheme + " theme 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.
-   */
-  AREA_PANEL: "PanelUI-contents",
-  /**
-   * Constant reference to the ID of the navigation toolbar.
-   */
-  AREA_NAVBAR: "nav-bar",
-  /**
-   * Constant reference to the ID of the menubar's toolbar.
-   */
-  AREA_MENUBAR: "toolbar-menubar",
-  /**
-   * Constant reference to the ID of the tabstrip toolbar.
-   */
-  AREA_TABSTRIP: "TabsToolbar",
-  /**
-   * Constant reference to the ID of the bookmarks toolbar.
-   */
-  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
-   */
-  AREA_ADDONBAR: "addon-bar",
-  /**
-   * Constant indicating the area is a menu panel.
-   */
-  TYPE_MENU_PANEL: "menu-panel",
-  /**
-   * Constant indicating the area is a toolbar.
-   */
-  TYPE_TOOLBAR: "toolbar",
-
-  /**
-   * Constant indicating a XUL-type provider.
-   */
-  PROVIDER_XUL: "xul",
-  /**
-   * Constant indicating an API-type provider.
-   */
-  PROVIDER_API: "api",
-  /**
-   * Constant indicating dynamic (special) widgets: spring, spacer, and separator.
-   */
-  PROVIDER_SPECIAL: "special",
-
-  /**
-   * Constant indicating the widget is built-in
-   */
-  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).
-   */
-  SOURCE_EXTERNAL: "external",
-
-  /**
-   * The class used to distinguish items that span the entire menu panel.
-   */
-  WIDE_PANEL_CLASS: "panel-wide-item",
-  /**
-   * The (constant) number of columns in the menu panel.
-   */
-  PANEL_COLUMN_COUNT: 3,
-
-  /**
-   * Constant indicating the reason the event was fired was a window closing
-   */
-  REASON_WINDOW_CLOSED: "window-closed",
-  /**
-   * Constant indicating the reason the event was fired was an area being
-   * unregistered separately from window closing mechanics.
-   */
-  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: {
-    *[Symbol.iterator]() {
-      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
-   *     to determine the width and height of widget aWidgetId when dragged to a
-   *     different area. aArea will be the area the item is dragged to, or
-   *     undefined after the measurements have been done and the node has been
-   *     moved back to its 'regular' area.
-   *
-   *   - onCustomizeStart(aWindow)
-   *     Fired when opening customize mode in aWindow.
-   *   - onCustomizeEnd(aWindow)
-   *     Fired when exiting customize mode in aWindow.
-   *
-   *   - onWidgetOverflow(aNode, aContainer)
-   *     Fired when a widget's DOM node is overflowing its container, a toolbar,
-   *     and will be displayed in the overflow panel.
-   *   - onWidgetUnderflow(aNode, aContainer)
-   *     Fired when a widget's DOM node is *not* overflowing its container, a
-   *     toolbar, anymore.
-   *   - onWindowOpened(aWindow)
-   *     Fired when a window has been opened that is managed by CustomizableUI,
-   *     once all of the prerequisite setup has been done.
-   *   - onWindowClosed(aWindow)
-   *     Fired when a window that has been managed by CustomizableUI has been
-   *     closed.
-   *   - onAreaNodeRegistered(aArea, aContainer)
-   *     Fired after an area node is first built when it is registered. This
-   *     is often when the window has opened, but in the case of add-ons,
-   *     could fire when the node has just been registered with CustomizableUI
-   *     after an add-on update or disable/enable sequence.
-   *   - onAreaNodeUnregistered(aArea, aContainer, aReason)
-   *     Fired when an area node is explicitly unregistered by an API caller,
-   *     or by a window closing. The aReason parameter indicates which of
-   *     these is the case.
-   */
-  addListener: function(aListener) {
-    CustomizableUIInternal.addListener(aListener);
-  },
-  /**
-   * Remove a listener added with addListener
-   * @param aListener the listener object to remove
-   */
-  removeListener: function(aListener) {
-    CustomizableUIInternal.removeListener(aListener);
-  },
-
-  /**
-   * Register a customizable area with CustomizableUI.
-   * @param aName   the name of the area to register. Can only contain
-   *                alphanumeric characters, dashes (-) and underscores (_).
-   * @param aProps  the properties of the area. The following properties are
-   *                recognized:
-   *                - type:   the type of area. Either TYPE_TOOLBAR (default) or
-   *                          TYPE_MENU_PANEL;
-   *                - anchor: for a menu panel or overflowable toolbar, the
-   *                          anchoring node for the panel.
-   *                - legacy: set to true if you want customizableui to
-   *                          automatically migrate the currentset attribute
-   *                - overflowable: set to true if your toolbar is overflowable.
-   *                                This requires an anchor, and only has an
-   *                                effect for toolbars.
-   *                - defaultPlacements: an array of widget IDs making up the
-   *                                     default contents of the area
-   *                - defaultCollapsed: (INTERNAL ONLY) applies if the type is TYPE_TOOLBAR, specifies
-   *                                    if toolbar is collapsed by default (default to true).
-   *                                    Specify null to ensure that reset/inDefaultArea don't care
-   *                                    about a toolbar's collapsed state
-   */
-  registerArea: function(aName, aProperties) {
-    CustomizableUIInternal.registerArea(aName, aProperties);
-  },
-  /**
-   * Register a concrete node for a registered area. This method is automatically
-   * called from any toolbar in the main browser window that has its
-   * "customizable" attribute set to true. There should normally be no need to
-   * call it yourself.
-   *
-   * Note that ideally, you should register your toolbar using registerArea
-   * before any of the toolbars have their XBL bindings constructed (which
-   * will happen when they're added to the DOM and are not hidden). If you
-   * don't, and your toolbar has a defaultset attribute, CustomizableUI will
-   * register it automatically. If your toolbar does not have a defaultset
-   * attribute, the node will be saved for processing when you call
-   * registerArea. Note that CustomizableUI won't restore state in the area,
-   * allow the user to customize it in customize mode, or otherwise deal
-   * with it, until the area has been registered.
-   */
-  registerToolbarNode: function(aToolbar, aExistingChildren) {
-    CustomizableUIInternal.registerToolbarNode(aToolbar, aExistingChildren);
-  },
-  /**
-   * Register the menu panel node. This method should not be called by anyone
-   * apart from the built-in PanelUI.
-   * @param aPanel the panel DOM node being registered.
-   */
-  registerMenuPanel: function(aPanel) {
-    CustomizableUIInternal.registerMenuPanel(aPanel);
-  },
-  /**
-   * Unregister a customizable area. The inverse of registerArea.
-   *
-   * Unregistering an area will remove all the (removable) widgets in the
-   * area, which will return to the panel, and destroy all other traces
-   * of the area within CustomizableUI. Note that this means the *contents*
-   * of the area's DOM nodes will be moved to the panel or removed, but
-   * the area's DOM nodes *themselves* will stay.
-   *
-   * Furthermore, by default the placements of the area will be kept in the
-   * saved state (!) and restored if you re-register the area at a later
-   * point. This is useful for e.g. add-ons that get disabled and then
-   * re-enabled (e.g. when they update).
-   *
-   * You can override this last behaviour (and destroy the placements
-   * information in the saved state) by passing true for aDestroyPlacements.
-   *
-   * @param aName              the name of the area to unregister
-   * @param aDestroyPlacements whether to destroy the placements information
-   *                           for the area, too.
-   */
-  unregisterArea: function(aName, aDestroyPlacements) {
-    CustomizableUIInternal.unregisterArea(aName, aDestroyPlacements);
-  },
-  /**
-   * Add a widget to an area.
-   * If the area to which you try to add is not known to CustomizableUI,
-   * this will throw.
-   * If the area to which you try to add has not yet been restored from its
-   * legacy state, this will postpone the addition.
-   * If the area to which you try to add is the same as the area in which
-   * the widget is currently placed, this will do the same as
-   * moveWidgetWithinArea.
-   * If the widget cannot be removed from its original location, this will
-   * no-op.
-   *
-   * This will fire an onWidgetAdded notification,
-   * and an onWidgetBeforeDOMChange and onWidgetAfterDOMChange notification
-   * for each window CustomizableUI knows about.
-   *
-   * @param aWidgetId the ID of the widget to add
-   * @param aArea     the ID of the area to add the widget to
-   * @param aPosition the position at which to add the widget. If you do not
-   *                  pass a position, the widget will be added to the end
-   *                  of the area.
-   */
-  addWidgetToArea: function(aWidgetId, aArea, aPosition) {
-    CustomizableUIInternal.addWidgetToArea(aWidgetId, aArea, aPosition);
-  },
-  /**
-   * Remove a widget from its area. If the widget cannot be removed from its
-   * area, or is not in any area, this will no-op. Otherwise, this will fire an
-   * onWidgetRemoved notification, and an onWidgetBeforeDOMChange and
-   * onWidgetAfterDOMChange notification for each window CustomizableUI knows
-   * about.
-   *
-   * @param aWidgetId the ID of the widget to remove
-   */
-  removeWidgetFromArea: function(aWidgetId) {
-    CustomizableUIInternal.removeWidgetFromArea(aWidgetId);
-  },
-  /**
-   * Move a widget within an area.
-   * If the widget is not in any area, this will no-op.
-   * If the widget is already at the indicated position, this will no-op.
-   *
-   * Otherwise, this will move the widget and fire an onWidgetMoved notification,
-   * and an onWidgetBeforeDOMChange and onWidgetAfterDOMChange notification for
-   * each window CustomizableUI knows about.
-   *
-   * @param aWidgetId the ID of the widget to move
-   * @param aPosition the position to move the widget to.
-   *                  Negative values or values greater than the number of
-   *                  widgets will be interpreted to mean moving the widget to
-   *                  respectively the first or last position.
-   */
-  moveWidgetWithinArea: function(aWidgetId, aPosition) {
-    CustomizableUIInternal.moveWidgetWithinArea(aWidgetId, aPosition);
-  },
-  /**
-   * Ensure a XUL-based widget created in a window after areas were
-   * initialized moves to its correct position.
-   * This is roughly equivalent to manually looking up the position and using
-   * insertItem in the old API, but a lot less work for consumers.
-   * Always prefer this over using toolbar.insertItem (which might no-op
-   * because it delegates to addWidgetToArea) or, worse, moving items in the
-   * DOM yourself.
-   *
-   * @param aWidgetId the ID of the widget that was just created
-   * @param aWindow the window in which you want to ensure it was added.
-   *
-   * NB: why is this API per-window, you wonder? Because if you need this,
-   * presumably you yourself need to create the widget in all the windows
-   * and need to loop through them anyway.
-   */
-  ensureWidgetPlacedInWindow: function(aWidgetId, aWindow) {
-    return CustomizableUIInternal.ensureWidgetPlacedInWindow(aWidgetId, aWindow);
-  },
-  /**
-   * Start a batch update of items.
-   * During a batch update, the customization state is not saved to the user's
-   * preferences file, in order to reduce (possibly sync) IO.
-   * Calls to begin/endBatchUpdate may be nested.
-   *
-   * Callers should ensure that NO MATTER WHAT they call endBatchUpdate once
-   * for each call to beginBatchUpdate, even if there are exceptions in the
-   * code in the batch update. Otherwise, for the duration of the
-   * Firefox session, customization state is never saved. Typically, you
-   * would do this using a try...finally block.
-   */
-  beginBatchUpdate: function() {
-    CustomizableUIInternal.beginBatchUpdate();
-  },
-  /**
-   * End a batch update. See the documentation for beginBatchUpdate above.
-   *
-   * State is not saved if we believe it is identical to the last known
-   * saved state. State is only ever saved when all batch updates have
-   * finished (ie there has been 1 endBatchUpdate call for each
-   * beginBatchUpdate call). If any of the endBatchUpdate calls pass
-   * aForceDirty=true, we will flush to the prefs file.
-   *
-   * @param aForceDirty force CustomizableUI to flush to the prefs file when
-   *                    all batch updates have finished.
-   */
-  endBatchUpdate: function(aForceDirty) {
-    CustomizableUIInternal.endBatchUpdate(aForceDirty);
-  },
-  /**
-   * Create a widget.
-   *
-   * To create a widget, you should pass an object with its desired
-   * properties. The following properties are supported:
-   *
-   * - id:            the ID of the widget (required).
-   * - type:          a string indicating the type of widget. Possible types
-   *                  are:
-   *                  'button' - for simple button widgets (the default)
-   *                  'view'   - for buttons that open a panel or subview,
-   *                             depending on where they are placed.
-   *                  'custom' - for fine-grained control over the creation
-   *                             of the widget.
-   * - viewId:        Only useful for views (and required there): the id of the
-   *                  <panelview> that should be shown when clicking the widget.
-   * - onBuild(aDoc): Only useful for custom widgets (and required there); a
-   *                  function that will be invoked with the document in which
-   *                  to build a widget. Should return the DOM node that has
-   *                  been constructed.
-   * - onBeforeCreated(aDoc): Attached to all non-custom widgets; a function
-   *                  that will be invoked before the widget gets a DOM node
-   *                  constructed, passing the document in which that will happen.
-   *                  This is useful especially for 'view' type widgets that need
-   *                  to construct their views on the fly (e.g. from bootstrapped
-   *                  add-ons)
-   * - onCreated(aNode): Attached to all widgets; a function that will be invoked
-   *                  whenever the widget has a DOM node constructed, passing the
-   *                  constructed node as an argument.
-   * - onDestroyed(aDoc): Attached to all non-custom widgets; a function that
-   *                  will be invoked after the widget has a DOM node destroyed,
-   *                  passing the document from which it was removed. This is
-   *                  useful especially for 'view' type widgets that need to
-   *                  cleanup after views that were constructed on the fly.
-   * - onCommand(aEvt): Only useful for button widgets; a function that will be
-   *                    invoked when the user activates the button.
-   * - onClick(aEvt): Attached to all widgets; a function that will be invoked
-   *                  when the user clicks the widget.
-   * - onViewShowing(aEvt): Only useful for views; a function that will be
-   *                  invoked when a user shows your view. If any event
-   *                  handler calls aEvt.preventDefault(), the view will
-   *                  not be shown.
-   *
-   *                  The event's `detail` property is an object with an
-   *                  `addBlocker` method. Handlers which need to
-   *                  perform asynchronous operations before the view is
-   *                  shown may pass this method a Promise, which will
-   *                  prevent the view from showing until it resolves.
-   *                  Additionally, if the promise resolves to the exact
-   *                  value `false`, the view will not be shown.
-   * - onViewHiding(aEvt): Only useful for views; a function that will be
-   *                  invoked when a user hides your view.
-   * - tooltiptext:   string to use for the tooltip of the widget
-   * - label:         string to use for the label of the widget
-   * - removable:     whether the widget is removable (optional, default: true)
-   *                  NB: if you specify false here, you must provide a
-   *                  defaultArea, too.
-   * - overflows:     whether widget can overflow when in an overflowable
-   *                  toolbar (optional, default: true)
-   * - defaultArea:   default area to add the widget to
-   *                  (optional, default: none; required if non-removable)
-   * - shortcutId:    id of an element that has a shortcut for this widget
-   *                  (optional, default: null). This is only used to display
-   *                  the shortcut as part of the tooltip for builtin widgets
-   *                  (which have strings inside
-   *                  customizableWidgets.properties). If you're in an add-on,
-   *                  you should not set this property.
-   * - showInPrivateBrowsing: whether to show the widget in private browsing
-   *                          mode (optional, default: true)
-   *
-   * @param aProperties the specifications for the widget.
-   * @return a wrapper around the created widget (see getWidget)
-   */
-  createWidget: function(aProperties) {
-    return CustomizableUIInternal.wrapWidget(
-      CustomizableUIInternal.createWidget(aProperties)
-    );
-  },
-  /**
-   * Destroy a widget
-   *
-   * If the widget is part of the default placements in an area, this will
-   * remove it from there. It will also remove any DOM instances. However,
-   * it will keep the widget in the placements for whatever area it was
-   * in at the time. You can remove it from there yourself by calling
-   * CustomizableUI.removeWidgetFromArea(aWidgetId).
-   *
-   * @param aWidgetId the ID of the widget to destroy
-   */
-  destroyWidget: function(aWidgetId) {
-    CustomizableUIInternal.destroyWidget(aWidgetId);
-  },
-  /**
-   * Get a wrapper object with information about the widget.
-   * The object provides the following properties
-   * (all read-only unless otherwise indicated):
-   *
-   * - id:            the widget's ID;
-   * - type:          the type of widget (button, view, custom). For
-   *                  XUL-provided widgets, this is always 'custom';
-   * - provider:      the provider type of the widget, id est one of
-   *                  PROVIDER_API or PROVIDER_XUL;
-   * - forWindow(w):  a method to obtain a single window wrapper for a widget,
-   *                  in the window w passed as the only argument;
-   * - instances:     an array of all instances (single window wrappers)
-   *                  of the widget. This array is NOT live;
-   * - areaType:      the type of the widget's current area
-   * - isGroup:       true; will be false for wrappers around single widget nodes;
-   * - source:        for API-provided widgets, whether they are built-in to
-   *                  Firefox or add-on-provided;
-   * - disabled:      for API-provided widgets, whether the widget is currently
-   *                  disabled. NB: this property is writable, and will toggle
-   *                  all the widgets' nodes' disabled states;
-   * - label:         for API-provied widgets, the label of the widget;
-   * - tooltiptext:   for API-provided widgets, the tooltip of the widget;
-   * - showInPrivateBrowsing: for API-provided widgets, whether the widget is
-   *                          visible in private browsing;
-   *
-   * Single window wrappers obtained through forWindow(someWindow) or from the
-   * instances array have the following properties
-   * (all read-only unless otherwise indicated):
-   *
-   * - id:            the widget's ID;
-   * - type:          the type of widget (button, view, custom). For
-   *                  XUL-provided widgets, this is always 'custom';
-   * - provider:      the provider type of the widget, id est one of
-   *                  PROVIDER_API or PROVIDER_XUL;
-   * - node:          reference to the corresponding DOM node;
-   * - anchor:        the anchor on which to anchor panels opened from this
-   *                  node. This will point to the overflow chevron on
-   *                  overflowable toolbars if and only if your widget node
-   *                  is overflowed, to the anchor for the panel menu
-   *                  if your widget is inside the panel menu, and to the
-   *                  node itself in all other cases;
-   * - overflowed:    boolean indicating whether the node is currently in the
-   *                  overflow panel of the toolbar;
-   * - isGroup:       false; will be true for the group widget;
-   * - label:         for API-provided widgets, convenience getter for the
-   *                  label attribute of the DOM node;
-   * - tooltiptext:   for API-provided widgets, convenience getter for the
-   *                  tooltiptext attribute of the DOM node;
-   * - disabled:      for API-provided widgets, convenience getter *and setter*
-   *                  for the disabled state of this single widget. Note that
-   *                  you may prefer to use the group wrapper's getter/setter
-   *                  instead.
-   *
-   * @param aWidgetId the ID of the widget whose information you need
-   * @return a wrapper around the widget as described above, or null if the
-   *         widget is known not to exist (anymore). NB: non-null return
-   *         is no guarantee the widget exists because we cannot know in
-   *         advance if a XUL widget exists or not.
-   */
-  getWidget: function(aWidgetId) {
-    return CustomizableUIInternal.wrapWidget(aWidgetId);
-  },
-  /**
-   * Get an array of widget wrappers (see getWidget) for all the widgets
-   * which are currently not in any area (so which are in the palette).
-   *
-   * @param aWindowPalette the palette (and by extension, the window) in which
-   *                       CustomizableUI should look. This matters because of
-   *                       course XUL-provided widgets could be available in
-   *                       some windows but not others, and likewise
-   *                       API-provided widgets might not exist in a private
-   *                       window (because of the showInPrivateBrowsing
-   *                       property).
-   *
-   * @return an array of widget wrappers (see getWidget)
-   */
-  getUnusedWidgets: function(aWindowPalette) {
-    return CustomizableUIInternal.getUnusedWidgets(aWindowPalette).map(
-      CustomizableUIInternal.wrapWidget,
-      CustomizableUIInternal
-    );
-  },
-  /**
-   * Get an array of all the widget IDs placed in an area. This is roughly
-   * equivalent to fetching the currentset attribute and splitting by commas
-   * in the legacy APIs. Modifying the array will not affect CustomizableUI.
-   *
-   * @param aArea the ID of the area whose placements you want to obtain.
-   * @return an array containing the widget IDs that are in the area.
-   *
-   * NB: will throw if called too early (before placements have been fetched)
-   *     or if the area is not currently known to CustomizableUI.
-   */
-  getWidgetIdsInArea: function(aArea) {
-    if (!gAreas.has(aArea)) {
-      throw new Error("Unknown customization area: " + aArea);
-    }
-    if (!gPlacements.has(aArea)) {
-      throw new Error("Area not yet restored");
-    }
-
-    // We need to clone this, as we don't want to let consumers muck with placements
-    return [...gPlacements.get(aArea)];
-  },
-  /**
-   * Get an array of widget wrappers for all the widgets in an area. This is
-   * the same as calling getWidgetIdsInArea and .map() ing the result through
-   * CustomizableUI.getWidget. Careful: this means that if there are IDs in there
-   * which don't have corresponding DOM nodes (like in the old-style currentset
-   * attribute), there might be nulls in this array, or items for which
-   * wrapper.forWindow(win) will return null.
-   *
-   * @param aArea the ID of the area whose widgets you want to obtain.
-   * @return an array of widget wrappers and/or null values for the widget IDs
-   *         placed in an area.
-   *
-   * NB: will throw if called too early (before placements have been fetched)
-   *     or if the area is not currently known to CustomizableUI.
-   */
-  getWidgetsInArea: function(aArea) {
-    return this.getWidgetIdsInArea(aArea).map(
-      CustomizableUIInternal.wrapWidget,
-      CustomizableUIInternal
-    );
-  },
-  /**
-   * Obtain an array of all the area IDs known to CustomizableUI.
-   * This array is created for you, so is modifiable without CustomizableUI
-   * being affected.
-   */
-  get areas() {
-    return [...gAreas.keys()];
-  },
-  /**
-   * Check what kind of area (toolbar or menu panel) an area is. This is
-   * useful if you have a widget that needs to behave differently depending
-   * on its location. Note that widget wrappers have a convenience getter
-   * property (areaType) for this purpose.
-   *
-   * @param aArea the ID of the area whose type you want to know
-   * @return TYPE_TOOLBAR or TYPE_MENU_PANEL depending on the area, null if
-   *         the area is unknown.
-   */
-  getAreaType: function(aArea) {
-    let area = gAreas.get(aArea);
-    return area ? area.get("type") : null;
-  },
-  /**
-   * Check if a toolbar is collapsed by default.
-   *
-   * @param aArea the ID of the area whose default-collapsed state you want to know.
-   * @return `true` or `false` depending on the area, null if the area is unknown,
-   *         or its collapsed state cannot normally be controlled by the user
-   */
-  isToolbarDefaultCollapsed: function(aArea) {
-    let area = gAreas.get(aArea);
-    return area ? area.get("defaultCollapsed") : null;
-  },
-  /**
-   * Obtain the DOM node that is the customize target for an area in a
-   * specific window.
-   *
-   * Areas can have a customization target that does not correspond to the
-   * node itself. In particular, toolbars that have a customizationtarget
-   * attribute set will have their customization target set to that node.
-   * This means widgets will end up in the customization target, not in the
-   * DOM node with the ID that corresponds to the area ID. This is useful
-   * because it lets you have fixed content in a toolbar (e.g. the panel
-   * menu item in the navbar) and have all the customizable widgets use
-   * the customization target.
-   *
-   * Using this API yourself is discouraged; you should generally not need
-   * to be asking for the DOM container node used for a particular area.
-   * In particular, if you're wanting to check it in relation to a widget's
-   * node, your DOM node might not be a direct child of the customize target
-   * in a window if, for instance, the window is in customization mode, or if
-   * this is an overflowable toolbar and the widget has been overflowed.
-   *
-   * @param aArea   the ID of the area whose customize target you want to have
-   * @param aWindow the window where you want to fetch the DOM node.
-   * @return the customize target DOM node for aArea in aWindow
-   */
-  getCustomizeTargetForArea: function(aArea, aWindow) {
-    return CustomizableUIInternal.getCustomizeTargetForArea(aArea, aWindow);
-  },
-  /**
-   * Reset the customization state back to its default.
-   *
-   * This is the nuclear option. You should never call this except if the user
-   * explicitly requests it. Firefox does this when the user clicks the
-   * "Restore Defaults" button in customize mode.
-   */
-  reset: function() {
-    CustomizableUIInternal.reset();
-  },
-
-  /**
-   * Undo the previous reset, can only be called immediately after a reset.
-   * @return a promise that will be resolved when the operation is complete.
-   */
-  undoReset: function() {
-    CustomizableUIInternal.undoReset();
-  },
-
-  /**
-   * Remove a custom toolbar added in a previous version of Firefox or using
-   * an add-on. NB: only works on the customizable toolbars generated by
-   * the toolbox itself. Intended for use from CustomizeMode, not by
-   * other consumers.
-   * @param aToolbarId the ID of the toolbar to remove
-   */
-  removeExtraToolbar: function(aToolbarId) {
-    CustomizableUIInternal.removeExtraToolbar(aToolbarId);
-  },
-
-  /**
-   * Can the last Restore Defaults operation be undone.
-   *
-   * @return A boolean stating whether an undo of the
-   *         Restore Defaults can be performed.
-   */
-  get canUndoReset() {
-    return gUIStateBeforeReset.uiCustomizationState != null ||
-           gUIStateBeforeReset.drawInTitlebar != null ||
-           gUIStateBeforeReset.currentTheme != null;
-  },
-
-  /**
-   * Get the placement of a widget. This is by far the best way to obtain
-   * information about what the state of your widget is. The internals of
-   * this call are cheap (no DOM necessary) and you will know where the user
-   * has put your widget.
-   *
-   * @param aWidgetId the ID of the widget whose placement you want to know
-   * @return
-   *   {
-   *     area: "somearea", // The ID of the area where the widget is placed
-   *     position: 42 // the index in the placements array corresponding to
-   *                  // your widget.
-   *   }
-   *
-   *   OR
-   *
-   *   null // if the widget is not placed anywhere (ie in the palette)
-   */
-  getPlacementOfWidget: function(aWidgetId, aOnlyRegistered=true, aDeadAreas=false) {
-    return CustomizableUIInternal.getPlacementOfWidget(aWidgetId, aOnlyRegistered, aDeadAreas);
-  },
-  /**
-   * Check if a widget can be removed from the area it's in.
-   *
-   * Note that if you're wanting to move the widget somewhere, you should
-   * generally be checking canWidgetMoveToArea, because that will return
-   * true if the widget is already in the area where you want to move it (!).
-   *
-   * NB: oh, also, this method might lie if the widget in question is a
-   *     XUL-provided widget and there are no windows open, because it
-   *     can obviously not check anything in this case. It will return
-   *     true. You will be able to move the widget elsewhere. However,
-   *     once the user reopens a window, the widget will move back to its
-   *     'proper' area automagically.
-   *
-   * @param aWidgetId a widget ID or DOM node to check
-   * @return true if the widget can be removed from its area,
-   *          false otherwise.
-   */
-  isWidgetRemovable: function(aWidgetId) {
-    return CustomizableUIInternal.isWidgetRemovable(aWidgetId);
-  },
-  /**
-   * Check if a widget can be moved to a particular area. Like
-   * isWidgetRemovable but better, because it'll return true if the widget
-   * is already in the right area.
-   *
-   * @param aWidgetId the widget ID or DOM node you want to move somewhere
-   * @param aArea     the area ID you want to move it to.
-   * @return true if this is possible, false if it is not. The same caveats as
-   *              for isWidgetRemovable apply, however, if no windows are open.
-   */
-  canWidgetMoveToArea: function(aWidgetId, aArea) {
-    return CustomizableUIInternal.canWidgetMoveToArea(aWidgetId, aArea);
-  },
-  /**
-   * Whether we're in a default state. Note that non-removable non-default
-   * widgets and non-existing widgets are not taken into account in determining
-   * whether we're in the default state.
-   *
-   * NB: this is a property with a getter. The getter is NOT cheap, because
-   * it does smart things with non-removable non-default items, non-existent
-   * items, and so forth. Please don't call unless necessary.
-   */
-  get inDefaultState() {
-    return CustomizableUIInternal.inDefaultState;
-  },
-
-  /**
-   * Set a toolbar's visibility state in all windows.
-   * @param aToolbarId    the toolbar whose visibility should be adjusted
-   * @param aIsVisible    whether the toolbar should be visible
-   */
-  setToolbarVisibility: function(aToolbarId, aIsVisible) {
-    CustomizableUIInternal.setToolbarVisibility(aToolbarId, aIsVisible);
-  },
-
-  /**
-   * Get a localized property off a (widget?) object.
-   *
-   * NB: this is unlikely to be useful unless you're in Firefox code, because
-   *     this code uses the builtin widget stringbundle, and can't be told
-   *     to use add-on-provided strings. It's mainly here as convenience for
-   *     custom builtin widgets that build their own DOM but use the same
-   *     stringbundle as the other builtin widgets.
-   *
-   * @param aWidget     the object whose property we should use to fetch a
-   *                    localizable string;
-   * @param aProp       the property on the object to use for the fetching;
-   * @param aFormatArgs (optional) any extra arguments to use for a formatted
-   *                    string;
-   * @param aDef        (optional) the default to return if we don't find the
-   *                    string in the stringbundle;
-   *
-   * @return the localized string, or aDef if the string isn't in the bundle.
-   *         If no default is provided,
-   *           if aProp exists on aWidget, we'll return that,
-   *           otherwise we'll return the empty string
-   *
-   */
-  getLocalizedProperty: function(aWidget, aProp, aFormatArgs, aDef) {
-    return CustomizableUIInternal.getLocalizedProperty(aWidget, aProp,
-      aFormatArgs, aDef);
-  },
-  /**
-   * Utility function to detect, find and set a keyboard shortcut for a menuitem
-   * or (toolbar)button.
-   *
-   * @param aShortcutNode the XUL node where the shortcut will be derived from;
-   * @param aTargetNode   (optional) the XUL node on which the `shortcut`
-   *                      attribute will be set. If NULL, the shortcut will be
-   *                      set on aShortcutNode;
-   */
-  addShortcut: function(aShortcutNode, aTargetNode) {
-    return CustomizableUIInternal.addShortcut(aShortcutNode, aTargetNode);
-  },
-  /**
-   * Given a node, walk up to the first panel in its ancestor chain, and
-   * close it.
-   *
-   * @param aNode a node whose panel should be closed;
-   */
-  hidePanelForNode: function(aNode) {
-    CustomizableUIInternal.hidePanelForNode(aNode);
-  },
-  /**
-   * Check if a widget is a "special" widget: a spring, spacer or separator.
-   *
-   * @param aWidgetId the widget ID to check.
-   * @return true if the widget is 'special', false otherwise.
-   */
-  isSpecialWidget: function(aWidgetId) {
-    return CustomizableUIInternal.isSpecialWidget(aWidgetId);
-  },
-  /**
-   * Add listeners to a panel that will close it. For use from the menu panel
-   * and overflowable toolbar implementations, unlikely to be useful for
-   * consumers.
-   *
-   * @param aPanel the panel to which listeners should be attached.
-   */
-  addPanelCloseListeners: function(aPanel) {
-    CustomizableUIInternal.addPanelCloseListeners(aPanel);
-  },
-  /**
-   * Remove close listeners that have been added to a panel with
-   * addPanelCloseListeners. For use from the menu panel and overflowable
-   * toolbar implementations, unlikely to be useful for consumers.
-   *
-   * @param aPanel the panel from which listeners should be removed.
-   */
-  removePanelCloseListeners: function(aPanel) {
-    CustomizableUIInternal.removePanelCloseListeners(aPanel);
-  },
-  /**
-   * Notify listeners a widget is about to be dragged to an area. For use from
-   * Customize Mode only, do not use otherwise.
-   *
-   * @param aWidgetId the ID of the widget that is being dragged to an area.
-   * @param aArea     the ID of the area to which the widget is being dragged.
-   */
-  onWidgetDrag: function(aWidgetId, aArea) {
-    CustomizableUIInternal.notifyListeners("onWidgetDrag", aWidgetId, aArea);
-  },
-  /**
-   * Notify listeners that a window is entering customize mode. For use from
-   * Customize Mode only, do not use otherwise.
-   * @param aWindow the window entering customize mode
-   */
-  notifyStartCustomizing: function(aWindow) {
-    CustomizableUIInternal.notifyListeners("onCustomizeStart", aWindow);
-  },
-  /**
-   * Notify listeners that a window is exiting customize mode. For use from
-   * Customize Mode only, do not use otherwise.
-   * @param aWindow the window exiting customize mode
-   */
-  notifyEndCustomizing: function(aWindow) {
-    CustomizableUIInternal.notifyListeners("onCustomizeEnd", aWindow);
-  },
-
-  /**
-   * Notify toolbox(es) of a particular event. If you don't pass aWindow,
-   * all toolboxes will be notified. For use from Customize Mode only,
-   * do not use otherwise.
-   * @param aEvent the name of the event to send.
-   * @param aDetails optional, the details of the event.
-   * @param aWindow optional, the window in which to send the event.
-   */
-  dispatchToolboxEvent: function(aEvent, aDetails={}, aWindow=null) {
-    CustomizableUIInternal.dispatchToolboxEvent(aEvent, aDetails, aWindow);
-  },
-
-  /**
-   * Check whether an area is overflowable.
-   *
-   * @param aAreaId the ID of an area to check for overflowable-ness
-   * @return true if the area is overflowable, false otherwise.
-   */
-  isAreaOverflowable: function(aAreaId) {
-    let area = gAreas.get(aAreaId);
-    return area ? area.get("type") == this.TYPE_TOOLBAR && area.get("overflowable")
-                : false;
-  },
-  /**
-   * Obtain a string indicating the place of an element. This is intended
-   * for use from customize mode; You should generally use getPlacementOfWidget
-   * instead, which is cheaper because it does not use the DOM.
-   *
-   * @param aElement the DOM node whose place we need to check
-   * @return "toolbar" if the node is in a toolbar, "panel" if it is in the
-   *         menu panel, "palette" if it is in the (visible!) customization
-   *         palette, undefined otherwise.
-   */
-  getPlaceForItem: function(aElement) {
-    let place;
-    let node = aElement;
-    while (node && !place) {
-      if (node.localName == "toolbar")
-        place = "toolbar";
-      else if (node.id == CustomizableUI.AREA_PANEL)
-        place = "panel";
-      else if (node.id == "customization-palette")
-        place = "palette";
-
-      node = node.parentNode;
-    }
-    return place;
-  },
-
-  /**
-   * Check if a toolbar is builtin or not.
-   * @param aToolbarId the ID of the toolbar you want to check
-   */
-  isBuiltinToolbar: function(aToolbarId) {
-    return CustomizableUIInternal._builtinToolbars.has(aToolbarId);
-  },
-};
-Object.freeze(this.CustomizableUI);
-Object.freeze(this.CustomizableUI.windows);
-
-/**
- * All external consumers of widgets are really interacting with these wrappers
- * which provide a common interface.
- */
-
-/**
- * WidgetGroupWrapper is the common interface for interacting with an entire
- * widget group - AKA, all instances of a widget across a series of windows.
- * This particular wrapper is only used for widgets created via the provider
- * API.
- */
-function WidgetGroupWrapper(aWidget) {
-  this.isGroup = true;
-
-  const kBareProps = ["id", "source", "type", "disabled", "label", "tooltiptext",
-                      "showInPrivateBrowsing", "viewId"];
-  for (let prop of kBareProps) {
-    let propertyName = prop;
-    this.__defineGetter__(propertyName, () => aWidget[propertyName]);
-  }
-
-  this.__defineGetter__("provider", () => CustomizableUI.PROVIDER_API);
-
-  this.__defineSetter__("disabled", function(aValue) {
-    aValue = !!aValue;
-    aWidget.disabled = aValue;
-    for (let [, instance] of aWidget.instances) {
-      instance.disabled = aValue;
-    }
-  });
-
-  this.forWindow = function WidgetGroupWrapper_forWindow(aWindow) {
-    let wrapperMap;
-    if (!gSingleWrapperCache.has(aWindow)) {
-      wrapperMap = new Map();
-      gSingleWrapperCache.set(aWindow, wrapperMap);
-    } else {
-      wrapperMap = gSingleWrapperCache.get(aWindow);
-    }
-    if (wrapperMap.has(aWidget.id)) {
-      return wrapperMap.get(aWidget.id);
-    }
-
-    let instance = aWidget.instances.get(aWindow.document);
-    if (!instance &&
-        (aWidget.showInPrivateBrowsing || !PrivateBrowsingUtils.isWindowPrivate(aWindow))) {
-      instance = CustomizableUIInternal.buildWidget(aWindow.document,
-                                                    aWidget);
-    }
-
-    let wrapper = new WidgetSingleWrapper(aWidget, instance);
-    wrapperMap.set(aWidget.id, wrapper);
-    return wrapper;
-  };
-
-  this.__defineGetter__("instances", function() {
-    // Can't use gBuildWindows here because some areas load lazily:
-    let placement = CustomizableUIInternal.getPlacementOfWidget(aWidget.id);
-    if (!placement) {
-      return [];
-    }
-    let area = placement.area;
-    let buildAreas = gBuildAreas.get(area);
-    if (!buildAreas) {
-      return [];
-    }
-    return Array.from(buildAreas, (node) => this.forWindow(node.ownerGlobal));
-  });
-
-  this.__defineGetter__("areaType", function() {
-    let areaProps = gAreas.get(aWidget.currentArea);
-    return areaProps && areaProps.get("type");
-  });
-
-  Object.freeze(this);
-}
-
-/**
- * A WidgetSingleWrapper is a wrapper around a single instance of a widget in
- * a particular window.
- */
-function WidgetSingleWrapper(aWidget, aNode) {
-  this.isGroup = false;
-
-  this.node = aNode;
-  this.provider = CustomizableUI.PROVIDER_API;
-
-  const kGlobalProps = ["id", "type"];
-  for (let prop of kGlobalProps) {
-    this[prop] = aWidget[prop];
-  }
-
-  const kNodeProps = ["label", "tooltiptext"];
-  for (let prop of kNodeProps) {
-    let propertyName = prop;
-    // Look at the node for these, instead of the widget data, to ensure the
-    // wrapper always reflects this live instance.
-    this.__defineGetter__(propertyName,
-                          () => aNode.getAttribute(propertyName));
-  }
-
-  this.__defineGetter__("disabled", () => aNode.disabled);
-  this.__defineSetter__("disabled", function(aValue) {
-    aNode.disabled = !!aValue;
-  });
-
-  this.__defineGetter__("anchor", function() {
-    let anchorId;
-    // First check for an anchor for the area:
-    let placement = CustomizableUIInternal.getPlacementOfWidget(aWidget.id);
-    if (placement) {
-      anchorId = gAreas.get(placement.area).get("anchor");
-    }
-    if (!anchorId) {
-      anchorId = aNode.getAttribute("cui-anchorid");
-    }
-
-    return anchorId ? aNode.ownerDocument.getElementById(anchorId)
-                    : aNode;
-  });
-
-  this.__defineGetter__("overflowed", function() {
-    return aNode.getAttribute("overflowedItem") == "true";
-  });
-
-  Object.freeze(this);
-}
-
-/**
- * XULWidgetGroupWrapper is the common interface for interacting with an entire
- * widget group - AKA, all instances of a widget across a series of windows.
- * This particular wrapper is only used for widgets created via the old-school
- * XUL method (overlays, or programmatically injecting toolbaritems, or other
- * such things).
- */
-// XXXunf Going to need to hook this up to some events to keep it all live.
-function XULWidgetGroupWrapper(aWidgetId) {
-  this.isGroup = true;
-  this.id = aWidgetId;
-  this.type = "custom";
-  this.provider = CustomizableUI.PROVIDER_XUL;
-
-  this.forWindow = function XULWidgetGroupWrapper_forWindow(aWindow) {
-    let wrapperMap;
-    if (!gSingleWrapperCache.has(aWindow)) {
-      wrapperMap = new Map();
-      gSingleWrapperCache.set(aWindow, wrapperMap);
-    } else {
-      wrapperMap = gSingleWrapperCache.get(aWindow);
-    }
-    if (wrapperMap.has(aWidgetId)) {
-      return wrapperMap.get(aWidgetId);
-    }
-
-    let instance = aWindow.document.getElementById(aWidgetId);
-    if (!instance) {
-      // Toolbar palettes aren't part of the document, so elements in there
-      // won't be found via document.getElementById().
-      instance = aWindow.gNavToolbox.palette.getElementsByAttribute("id", aWidgetId)[0];
-    }
-
-    let wrapper = new XULWidgetSingleWrapper(aWidgetId, instance, aWindow.document);
-    wrapperMap.set(aWidgetId, wrapper);
-    return wrapper;
-  };
-
-  this.__defineGetter__("areaType", function() {
-    let placement = CustomizableUIInternal.getPlacementOfWidget(aWidgetId);
-    if (!placement) {
-      return null;
-    }
-
-    let areaProps = gAreas.get(placement.area);
-    return areaProps && areaProps.get("type");
-  });
-
-  this.__defineGetter__("instances", function() {
-    return Array.from(gBuildWindows, (wins) => this.forWindow(wins[0]));
-  });
-
-  Object.freeze(this);
-}
-
-/**
- * A XULWidgetSingleWrapper is a wrapper around a single instance of a XUL
- * widget in a particular window.
- */
-function XULWidgetSingleWrapper(aWidgetId, aNode, aDocument) {
-  this.isGroup = false;
-
-  this.id = aWidgetId;
-  this.type = "custom";
-  this.provider = CustomizableUI.PROVIDER_XUL;
-
-  let weakDoc = Cu.getWeakReference(aDocument);
-  // If we keep a strong ref, the weak ref will never die, so null it out:
-  aDocument = null;
-
-  this.__defineGetter__("node", function() {
-    // If we've set this to null (further down), we're sure there's nothing to
-    // be gotten here, so bail out early:
-    if (!weakDoc) {
-      return null;
-    }
-    if (aNode) {
-      // Return the last known node if it's still in the DOM...
-      if (aNode.ownerDocument.contains(aNode)) {
-        return aNode;
-      }
-      // ... or the toolbox
-      let toolbox = aNode.ownerGlobal.gNavToolbox;
-      if (toolbox && toolbox.palette && aNode.parentNode == toolbox.palette) {
-        return aNode;
-      }
-      // If it isn't, clear the cached value and fall through to the "slow" case:
-      aNode = null;
-    }
-
-    let doc = weakDoc.get();
-    if (doc) {
-      // Store locally so we can cache the result:
-      aNode = CustomizableUIInternal.findWidgetInWindow(aWidgetId, doc.defaultView);
-      return aNode;
-    }
-    // The weakref to the document is dead, we're done here forever more:
-    weakDoc = null;
-    return null;
-  });
-
-  this.__defineGetter__("anchor", function() {
-    let anchorId;
-    // First check for an anchor for the area:
-    let placement = CustomizableUIInternal.getPlacementOfWidget(aWidgetId);
-    if (placement) {
-      anchorId = gAreas.get(placement.area).get("anchor");
-    }
-
-    let node = this.node;
-    if (!anchorId && node) {
-      anchorId = node.getAttribute("cui-anchorid");
-    }
-
-    return (anchorId && node) ? node.ownerDocument.getElementById(anchorId) : node;
-  });
-
-  this.__defineGetter__("overflowed", function() {
-    let node = this.node;
-    if (!node) {
-      return false;
-    }
-    return node.getAttribute("overflowedItem") == "true";
-  });
-
-  Object.freeze(this);
-}
-
-const LAZY_RESIZE_INTERVAL_MS = 200;
-const OVERFLOW_PANEL_HIDE_DELAY_MS = 500;
-
-function OverflowableToolbar(aToolbarNode) {
-  this._toolbar = aToolbarNode;
-  this._collapsed = new Map();
-  this._enabled = true;
-
-  this._toolbar.setAttribute("overflowable", "true");
-  let doc = this._toolbar.ownerDocument;
-  this._target = this._toolbar.customizationTarget;
-  this._list = doc.getElementById(this._toolbar.getAttribute("overflowtarget"));
-  this._list.toolbox = this._toolbar.toolbox;
-  this._list.customizationTarget = this._list;
-
-  let window = this._toolbar.ownerGlobal;
-  if (window.gBrowserInit.delayedStartupFinished) {
-    this.init();
-  } else {
-    Services.obs.addObserver(this, "browser-delayed-startup-finished", false);
-  }
-}
-
-OverflowableToolbar.prototype = {
-  initialized: false,
-  _forceOnOverflow: false,
-
-  observe: function(aSubject, aTopic, aData) {
-    if (aTopic == "browser-delayed-startup-finished" &&
-        aSubject == this._toolbar.ownerGlobal) {
-      Services.obs.removeObserver(this, "browser-delayed-startup-finished");
-      this.init();
-    }
-  },
-
-  init: function() {
-    let doc = this._toolbar.ownerDocument;
-    let window = doc.defaultView;
-    window.addEventListener("resize", this);
-    window.gNavToolbox.addEventListener("customizationstarting", this);
-    window.gNavToolbox.addEventListener("aftercustomization", this);
-
-    let chevronId = this._toolbar.getAttribute("overflowbutton");
-    this._chevron = doc.getElementById(chevronId);
-    this._chevron.addEventListener("command", this);
-    this._chevron.addEventListener("dragover", this);
-    this._chevron.addEventListener("dragend", this);
-
-    let panelId = this._toolbar.getAttribute("overflowpanel");
-    this._panel = doc.getElementById(panelId);
-    this._panel.addEventListener("popuphiding", this);
-    CustomizableUIInternal.addPanelCloseListeners(this._panel);
-
-    CustomizableUI.addListener(this);
-
-    // The 'overflow' event may have been fired before init was called.
-    if (this._toolbar.overflowedDuringConstruction) {
-      this.onOverflow(this._toolbar.overflowedDuringConstruction);
-      this._toolbar.overflowedDuringConstruction = null;
-    }
-
-    this.initialized = true;
-  },
-
-  uninit: function() {
-    this._toolbar.removeEventListener("overflow", this._toolbar);
-    this._toolbar.removeEventListener("underflow", this._toolbar);
-    this._toolbar.removeAttribute("overflowable");
-
-    if (!this.initialized) {
-      Services.obs.removeObserver(this, "browser-delayed-startup-finished");
-      return;
-    }
-
-    this._disable();
-
-    let window = this._toolbar.ownerGlobal;
-    window.removeEventListener("resize", this);
-    window.gNavToolbox.removeEventListener("customizationstarting", this);
-    window.gNavToolbox.removeEventListener("aftercustomization", this);
-    this._chevron.removeEventListener("command", this);
-    this._chevron.removeEventListener("dragover", this);
-    this._chevron.removeEventListener("dragend", this);
-    this._panel.removeEventListener("popuphiding", this);
-    CustomizableUI.removeListener(this);
-    CustomizableUIInternal.removePanelCloseListeners(this._panel);
-  },
-
-  handleEvent: function(aEvent) {
-    switch (aEvent.type) {
-      case "aftercustomization":
-        this._enable();
-        break;
-      case "command":
-        if (aEvent.target == this._chevron) {
-          this._onClickChevron(aEvent);
-        } else {
-          this._panel.hidePopup();
-        }
-        break;
-      case "customizationstarting":
-        this._disable();
-        break;
-      case "dragover":
-        this._showWithTimeout();
-        break;
-      case "dragend":
-        this._panel.hidePopup();
-        break;
-      case "popuphiding":
-        this._onPanelHiding(aEvent);
-        break;
-      case "resize":
-        this._onResize(aEvent);
-    }
-  },
-
-  show: function() {
-    if (this._panel.state == "open") {
-      return Promise.resolve();
-    }
-    return new Promise(resolve => {
-      let doc = this._panel.ownerDocument;
-      this._panel.hidden = false;
-      let contextMenu = doc.getElementById(this._panel.getAttribute("context"));
-      gELS.addSystemEventListener(contextMenu, 'command', this, true);
-      let anchor = doc.getAnonymousElementByAttribute(this._chevron, "class", "toolbarbutton-icon");
-      this._panel.openPopup(anchor || this._chevron);
-      this._chevron.open = true;
-
-      let overflowableToolbarInstance = this;
-      this._panel.addEventListener("popupshown", function onPopupShown(aEvent) {
-        this.removeEventListener("popupshown", onPopupShown);
-        this.addEventListener("dragover", overflowableToolbarInstance);
-        this.addEventListener("dragend", overflowableToolbarInstance);
-        resolve();
-      });
-    });
-  },
-
-  _onClickChevron: function(aEvent) {
-    if (this._chevron.open) {
-      this._panel.hidePopup();
-      this._chevron.open = false;
-    } else {
-      this.show();
-    }
-  },
-
-  _onPanelHiding: function(aEvent) {
-    this._chevron.open = false;
-    this._panel.removeEventListener("dragover", this);
-    this._panel.removeEventListener("dragend", this);
-    let doc = aEvent.target.ownerDocument;
-    let contextMenu = doc.getElementById(this._panel.getAttribute("context"));
-    gELS.removeSystemEventListener(contextMenu, 'command', this, true);
-  },
-
-  onOverflow: function(aEvent) {
-    // The rangeParent check is here because of bug 1111986 and ensuring that
-    // overflow events from the bookmarks toolbar items or similar things that
-    // manage their own overflow don't trigger an overflow on the entire toolbar
-    if (!this._enabled ||
-        (aEvent && aEvent.target != this._toolbar.customizationTarget) ||
-        (aEvent && aEvent.rangeParent))
-      return;
-
-    let child = this._target.lastChild;
-
-    while (child && this._target.scrollLeftMin != this._target.scrollLeftMax) {
-      let prevChild = child.previousSibling;
-
-      if (child.getAttribute("overflows") != "false") {
-        this._collapsed.set(child.id, this._target.clientWidth);
-        child.setAttribute("overflowedItem", true);
-        child.setAttribute("cui-anchorid", this._chevron.id);
-        CustomizableUIInternal.notifyListeners("onWidgetOverflow", child, this._target);
-
-        this._list.insertBefore(child, this._list.firstChild);
-        if (!this._toolbar.hasAttribute("overflowing")) {
-          CustomizableUI.addListener(this);
-        }
-        this._toolbar.setAttribute("overflowing", "true");
-      }
-      child = prevChild;
-    }
-
-    let win = this._target.ownerGlobal;
-    win.UpdateUrlbarSearchSplitterState();
-  },
-
-  _onResize: function(aEvent) {
-    if (!this._lazyResizeHandler) {
-      this._lazyResizeHandler = new DeferredTask(this._onLazyResize.bind(this),
-                                                 LAZY_RESIZE_INTERVAL_MS);
-    }
-    this._lazyResizeHandler.arm();
-  },
-
-  _moveItemsBackToTheirOrigin: function(shouldMoveAllItems) {
-    let placements = gPlacements.get(this._toolbar.id);
-    while (this._list.firstChild) {
-      let child = this._list.firstChild;
-      let minSize = this._collapsed.get(child.id);
-
-      if (!shouldMoveAllItems &&
-          minSize &&
-          this._target.clientWidth <= minSize) {
-        return;
-      }
-
-      this._collapsed.delete(child.id);
-      let beforeNodeIndex = placements.indexOf(child.id) + 1;
-      // If this is a skipintoolbarset item, meaning it doesn't occur in the placements list,
-      // we're inserting it at the end. This will mean first-in, first-out (more or less)
-      // leading to as little change in order as possible.
-      if (beforeNodeIndex == 0) {
-        beforeNodeIndex = placements.length;
-      }
-      let inserted = false;
-      for (; beforeNodeIndex < placements.length; beforeNodeIndex++) {
-        let beforeNode = this._target.getElementsByAttribute("id", placements[beforeNodeIndex])[0];
-        if (beforeNode) {
-          this._target.insertBefore(child, beforeNode);
-          inserted = true;
-          break;
-        }
-      }
-      if (!inserted) {
-        this._target.appendChild(child);
-      }
-      child.removeAttribute("cui-anchorid");
-      child.removeAttribute("overflowedItem");
-      CustomizableUIInternal.notifyListeners("onWidgetUnderflow", child, this._target);
-    }
-
-    let win = this._target.ownerGlobal;
-    win.UpdateUrlbarSearchSplitterState();
-
-    if (!this._collapsed.size) {
-      this._toolbar.removeAttribute("overflowing");
-      CustomizableUI.removeListener(this);
-    }
-  },
-
-  _onLazyResize: function() {
-    if (!this._enabled)
-      return;
-
-    if (this._target.scrollLeftMin != this._target.scrollLeftMax) {
-      this.onOverflow();
-    } else {
-      this._moveItemsBackToTheirOrigin();
-    }
-  },
-
-  _disable: function() {
-    this._enabled = false;
-    this._moveItemsBackToTheirOrigin(true);
-    if (this._lazyResizeHandler) {
-      this._lazyResizeHandler.disarm();
-    }
-  },
-
-  _enable: function() {
-    this._enabled = true;
-    this.onOverflow();
-  },
-
-  onWidgetBeforeDOMChange: function(aNode, aNextNode, aContainer) {
-    if (aContainer != this._target && aContainer != this._list) {
-      return;
-    }
-    // When we (re)move an item, update all the items that come after it in the list
-    // with the minsize *of the item before the to-be-removed node*. This way, we
-    // ensure that we try to move items back as soon as that's possible.
-    if (aNode.parentNode == this._list) {
-      let updatedMinSize;
-      if (aNode.previousSibling) {
-        updatedMinSize = this._collapsed.get(aNode.previousSibling.id);
-      } else {
-        // Force (these) items to try to flow back into the bar:
-        updatedMinSize = 1;
-      }
-      let nextItem = aNode.nextSibling;
-      while (nextItem) {
-        this._collapsed.set(nextItem.id, updatedMinSize);
-        nextItem = nextItem.nextSibling;
-      }
-    }
-  },
-
-  onWidgetAfterDOMChange: function(aNode, aNextNode, aContainer) {
-    if (aContainer != this._target && aContainer != this._list) {
-      return;
-    }
-
-    let nowInBar = aNode.parentNode == aContainer;
-    let nowOverflowed = aNode.parentNode == this._list;
-    let wasOverflowed = this._collapsed.has(aNode.id);
-
-    // If this wasn't overflowed before...
-    if (!wasOverflowed) {
-      // ... but it is now, then we added to the overflow panel. Exciting stuff:
-      if (nowOverflowed) {
-        // NB: we're guaranteed that it has a previousSibling, because if it didn't,
-        // we would have added it to the toolbar instead. See getOverflowedNextNode.
-        let prevId = aNode.previousSibling.id;
-        let minSize = this._collapsed.get(prevId);
-        this._collapsed.set(aNode.id, minSize);
-        aNode.setAttribute("cui-anchorid", this._chevron.id);
-        aNode.setAttribute("overflowedItem", true);
-        CustomizableUIInternal.notifyListeners("onWidgetOverflow", aNode, this._target);
-      }
-      // If it is not overflowed and not in the toolbar, and was not overflowed
-      // either, it moved out of the toolbar. That means there's now space in there!
-      // Let's try to move stuff back:
-      else if (!nowInBar) {
-        this._moveItemsBackToTheirOrigin(true);
-      }
-      // If it's in the toolbar now, then we don't care. An overflow event may
-      // fire afterwards; that's ok!
-    }
-    // If it used to be overflowed...
-    else if (!nowOverflowed) {
-      // ... and isn't anymore, let's remove our bookkeeping:
-      this._collapsed.delete(aNode.id);
-      aNode.removeAttribute("cui-anchorid");
-      aNode.removeAttribute("overflowedItem");
-      CustomizableUIInternal.notifyListeners("onWidgetUnderflow", aNode, this._target);
-
-      if (!this._collapsed.size) {
-        this._toolbar.removeAttribute("overflowing");
-        CustomizableUI.removeListener(this);
-      }
-    } else if (aNode.previousSibling) {
-      // but if it still is, it must have changed places. Bookkeep:
-      let prevId = aNode.previousSibling.id;
-      let minSize = this._collapsed.get(prevId);
-      this._collapsed.set(aNode.id, minSize);
-    } else {
-      // If it's now the first item in the overflow list,
-      // maybe we can return it:
-      this._moveItemsBackToTheirOrigin();
-    }
-  },
-
-  findOverflowedInsertionPoints: function(aNode) {
-    let newNodeCanOverflow = aNode.getAttribute("overflows") != "false";
-    let areaId = this._toolbar.id;
-    let placements = gPlacements.get(areaId);
-    let nodeIndex = placements.indexOf(aNode.id);
-    let nodeBeforeNewNodeIsOverflown = false;
-
-    let loopIndex = -1;
-    while (++loopIndex < placements.length) {
-      let nextNodeId = placements[loopIndex];
-      if (loopIndex > nodeIndex) {
-        if (newNodeCanOverflow && this._collapsed.has(nextNodeId)) {
-          let nextNode = this._list.getElementsByAttribute("id", nextNodeId).item(0);
-          if (nextNode) {
-            return [this._list, nextNode];
-          }
-        }
-        if (!nodeBeforeNewNodeIsOverflown || !newNodeCanOverflow) {
-          let nextNode = this._target.getElementsByAttribute("id", nextNodeId).item(0);
-          if (nextNode) {
-            return [this._target, nextNode];
-          }
-        }
-      } else if (loopIndex < nodeIndex && this._collapsed.has(nextNodeId)) {
-        nodeBeforeNewNodeIsOverflown = true;
-      }
-    }
-
-    let containerForAppending = (this._collapsed.size && newNodeCanOverflow) ?
-                                this._list : this._target;
-    return [containerForAppending, null];
-  },
-
-  getContainerFor: function(aNode) {
-    if (aNode.getAttribute("overflowedItem") == "true") {
-      return this._list;
-    }
-    return this._target;
-  },
-
-  _hideTimeoutId: null,
-  _showWithTimeout: function() {
-    this.show().then(function () {
-      let window = this._toolbar.ownerGlobal;
-      if (this._hideTimeoutId) {
-        window.clearTimeout(this._hideTimeoutId);
-      }
-      this._hideTimeoutId = window.setTimeout(() => {
-        if (!this._panel.firstChild.matches(":hover")) {
-          this._panel.hidePopup();
-        }
-      }, OVERFLOW_PANEL_HIDE_DELAY_MS);
-    }.bind(this));
-  },
-};
-
-CustomizableUIInternal.initialize();
diff --git a/browser/components/customizableui/CustomizableWidgets.jsm b/browser/components/customizableui/CustomizableWidgets.jsm
deleted file mode 100644
index 3e00d385f..000000000
--- a/browser/components/customizableui/CustomizableWidgets.jsm
+++ /dev/null
@@ -1,1219 +0,0 @@
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-"use strict";
-const {classes: Cc, interfaces: Ci, utils: Cu, results: Cr} = Components;
-
-this.EXPORTED_SYMBOLS = ["CustomizableWidgets"];
-
-Cu.import("resource:///modules/CustomizableUI.jsm");
-Cu.import("resource://gre/modules/Services.jsm");
-Cu.import("resource://gre/modules/XPCOMUtils.jsm");
-Cu.import("resource://gre/modules/AppConstants.jsm");
-XPCOMUtils.defineLazyModuleGetter(this, "BrowserUITelemetry",
-  "resource:///modules/BrowserUITelemetry.jsm");
-XPCOMUtils.defineLazyModuleGetter(this, "PlacesUtils",
-  "resource://gre/modules/PlacesUtils.jsm");
-XPCOMUtils.defineLazyModuleGetter(this, "PlacesUIUtils",
-  "resource:///modules/PlacesUIUtils.jsm");
-XPCOMUtils.defineLazyModuleGetter(this, "RecentlyClosedTabsAndWindowsMenuUtils",
-  "resource:///modules/sessionstore/RecentlyClosedTabsAndWindowsMenuUtils.jsm");
-XPCOMUtils.defineLazyModuleGetter(this, "ShortcutUtils",
-  "resource://gre/modules/ShortcutUtils.jsm");
-XPCOMUtils.defineLazyModuleGetter(this, "CharsetMenu",
-  "resource://gre/modules/CharsetMenu.jsm");
-XPCOMUtils.defineLazyModuleGetter(this, "PrivateBrowsingUtils",
-  "resource://gre/modules/PrivateBrowsingUtils.jsm");
-XPCOMUtils.defineLazyModuleGetter(this, "SyncedTabs",
-  "resource://services-sync/SyncedTabs.jsm");
-XPCOMUtils.defineLazyModuleGetter(this, "ContextualIdentityService",
-  "resource://gre/modules/ContextualIdentityService.jsm");
-
-XPCOMUtils.defineLazyGetter(this, "CharsetBundle", function() {
-  const kCharsetBundle = "chrome://global/locale/charsetMenu.properties";
-  return Services.strings.createBundle(kCharsetBundle);
-});
-XPCOMUtils.defineLazyGetter(this, "BrandBundle", function() {
-  const kBrandBundle = "chrome://branding/locale/brand.properties";
-  return Services.strings.createBundle(kBrandBundle);
-});
-
-const kNSXUL = "http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul";
-const kPrefCustomizationDebug = "browser.uiCustomization.debug";
-const kWidePanelItemClass = "panel-wide-item";
-
-XPCOMUtils.defineLazyGetter(this, "log", () => {
-  let scope = {};
-  Cu.import("resource://gre/modules/Console.jsm", scope);
-  let debug;
-  try {
-    debug = Services.prefs.getBoolPref(kPrefCustomizationDebug);
-  } catch (ex) {}
-  let consoleOptions = {
-    maxLogLevel: debug ? "all" : "log",
-    prefix: "CustomizableWidgets",
-  };
-  return new scope.ConsoleAPI(consoleOptions);
-});
-
-
-
-function setAttributes(aNode, aAttrs) {
-  let doc = aNode.ownerDocument;
-  for (let [name, value] of Object.entries(aAttrs)) {
-    if (!value) {
-      if (aNode.hasAttribute(name))
-        aNode.removeAttribute(name);
-    } else {
-      if (name == "shortcutId") {
-        continue;
-      }
-      if (name == "label" || name == "tooltiptext") {
-        let stringId = (typeof value == "string") ? value : name;
-        let additionalArgs = [];
-        if (aAttrs.shortcutId) {
-          let shortcut = doc.getElementById(aAttrs.shortcutId);
-          if (shortcut) {
-            additionalArgs.push(ShortcutUtils.prettifyShortcut(shortcut));
-          }
-        }
-        value = CustomizableUI.getLocalizedProperty({id: aAttrs.id}, stringId, additionalArgs);
-      }
-      aNode.setAttribute(name, value);
-    }
-  }
-}
-
-function updateCombinedWidgetStyle(aNode, aArea, aModifyCloseMenu) {
-  let inPanel = (aArea == CustomizableUI.AREA_PANEL);
-  let cls = inPanel ? "panel-combined-button" : "toolbarbutton-1 toolbarbutton-combined";
-  let attrs = {class: cls};
-  if (aModifyCloseMenu) {
-    attrs.closemenu = inPanel ? "none" : null;
-  }
-  for (let i = 0, l = aNode.childNodes.length; i < l; ++i) {
-    if (aNode.childNodes[i].localName == "separator")
-      continue;
-    setAttributes(aNode.childNodes[i], attrs);
-  }
-}
-
-function fillSubviewFromMenuItems(aMenuItems, aSubview) {
-  let attrs = ["oncommand", "onclick", "label", "key", "disabled",
-               "command", "observes", "hidden", "class", "origin",
-               "image", "checked"];
-
-  let doc = aSubview.ownerDocument;
-  let fragment = doc.createDocumentFragment();
-  for (let menuChild of aMenuItems) {
-    if (menuChild.hidden)
-      continue;
-
-    let subviewItem;
-    if (menuChild.localName == "menuseparator") {
-      // Don't insert duplicate or leading separators. This can happen if there are
-      // menus (which we don't copy) above the separator.
-      if (!fragment.lastChild || fragment.lastChild.localName == "menuseparator") {
-        continue;
-      }
-      subviewItem = doc.createElementNS(kNSXUL, "menuseparator");
-    } else if (menuChild.localName == "menuitem") {
-      subviewItem = doc.createElementNS(kNSXUL, "toolbarbutton");
-      CustomizableUI.addShortcut(menuChild, subviewItem);
-
-      let item = menuChild;
-      if (!item.hasAttribute("onclick")) {
-        subviewItem.addEventListener("click", event => {
-          let newEvent = new doc.defaultView.MouseEvent(event.type, event);
-          item.dispatchEvent(newEvent);
-        });
-      }
-
-      if (!item.hasAttribute("oncommand")) {
-        subviewItem.addEventListener("command", event => {
-          let newEvent = doc.createEvent("XULCommandEvent");
-          newEvent.initCommandEvent(
-            event.type, event.bubbles, event.cancelable, event.view,
-            event.detail, event.ctrlKey, event.altKey, event.shiftKey,
-            event.metaKey, event.sourceEvent);
-          item.dispatchEvent(newEvent);
-        });
-      }
-    } else {
-      continue;
-    }
-    for (let attr of attrs) {
-      let attrVal = menuChild.getAttribute(attr);
-      if (attrVal)
-        subviewItem.setAttribute(attr, attrVal);
-    }
-    // We do this after so the .subviewbutton class doesn't get overriden.
-    if (menuChild.localName == "menuitem") {
-      subviewItem.classList.add("subviewbutton");
-    }
-    fragment.appendChild(subviewItem);
-  }
-  aSubview.appendChild(fragment);
-}
-
-function clearSubview(aSubview) {
-  let parent = aSubview.parentNode;
-  // We'll take the container out of the document before cleaning it out
-  // to avoid reflowing each time we remove something.
-  parent.removeChild(aSubview);
-
-  while (aSubview.firstChild) {
-    aSubview.firstChild.remove();
-  }
-
-  parent.appendChild(aSubview);
-}
-
-const CustomizableWidgets = [
-  {
-    id: "history-panelmenu",
-    type: "view",
-    viewId: "PanelUI-history",
-    shortcutId: "key_gotoHistory",
-    tooltiptext: "history-panelmenu.tooltiptext2",
-    defaultArea: CustomizableUI.AREA_PANEL,
-    onViewShowing: function(aEvent) {
-      // Populate our list of history
-      const kMaxResults = 15;
-      let doc = aEvent.target.ownerDocument;
-      let win = doc.defaultView;
-
-      let options = PlacesUtils.history.getNewQueryOptions();
-      options.excludeQueries = true;
-      options.queryType = options.QUERY_TYPE_HISTORY;
-      options.sortingMode = options.SORT_BY_DATE_DESCENDING;
-      options.maxResults = kMaxResults;
-      let query = PlacesUtils.history.getNewQuery();
-
-      let items = doc.getElementById("PanelUI-historyItems");
-      // Clear previous history items.
-      while (items.firstChild) {
-        items.firstChild.remove();
-      }
-
-      // Get all statically placed buttons to supply them with keyboard shortcuts.
-      let staticButtons = items.parentNode.getElementsByTagNameNS(kNSXUL, "toolbarbutton");
-      for (let i = 0, l = staticButtons.length; i < l; ++i)
-        CustomizableUI.addShortcut(staticButtons[i]);
-
-      PlacesUtils.history.QueryInterface(Ci.nsPIPlacesDatabase)
-                         .asyncExecuteLegacyQueries([query], 1, options, {
-        handleResult: function (aResultSet) {
-          let onItemCommand = function (aEvent) {
-            // Only handle the click event for middle clicks, we're using the command
-            // event otherwise.
-            if (aEvent.type == "click" && aEvent.button != 1) {
-              return;
-            }
-            let item = aEvent.target;
-            win.openUILink(item.getAttribute("targetURI"), aEvent);
-            CustomizableUI.hidePanelForNode(item);
-          };
-          let fragment = doc.createDocumentFragment();
-          let row;
-          while ((row = aResultSet.getNextRow())) {
-            let uri = row.getResultByIndex(1);
-            let title = row.getResultByIndex(2);
-            let icon = row.getResultByIndex(6);
-
-            let item = doc.createElementNS(kNSXUL, "toolbarbutton");
-            item.setAttribute("label", title || uri);
-            item.setAttribute("targetURI", uri);
-            item.setAttribute("class", "subviewbutton");
-            item.addEventListener("command", onItemCommand);
-            item.addEventListener("click", onItemCommand);
-            if (icon) {
-              let iconURL = "moz-anno:favicon:" + icon;
-              item.setAttribute("image", iconURL);
-            }
-            fragment.appendChild(item);
-          }
-          items.appendChild(fragment);
-        },
-        handleError: function (aError) {
-          log.debug("History view tried to show but had an error: " + aError);
-        },
-        handleCompletion: function (aReason) {
-          log.debug("History view is being shown!");
-        },
-      });
-
-      let recentlyClosedTabs = doc.getElementById("PanelUI-recentlyClosedTabs");
-      while (recentlyClosedTabs.firstChild) {
-        recentlyClosedTabs.removeChild(recentlyClosedTabs.firstChild);
-      }
-
-      let recentlyClosedWindows = doc.getElementById("PanelUI-recentlyClosedWindows");
-      while (recentlyClosedWindows.firstChild) {
-        recentlyClosedWindows.removeChild(recentlyClosedWindows.firstChild);
-      }
-
-      let utils = RecentlyClosedTabsAndWindowsMenuUtils;
-      let tabsFragment = utils.getTabsFragment(doc.defaultView, "toolbarbutton", true,
-                                               "menuRestoreAllTabsSubview.label");
-      let separator = doc.getElementById("PanelUI-recentlyClosedTabs-separator");
-      let elementCount = tabsFragment.childElementCount;
-      separator.hidden = !elementCount;
-      while (--elementCount >= 0) {
-        tabsFragment.children[elementCount].classList.add("subviewbutton", "cui-withicon");
-      }
-      recentlyClosedTabs.appendChild(tabsFragment);
-
-      let windowsFragment = utils.getWindowsFragment(doc.defaultView, "toolbarbutton", true,
-                                                     "menuRestoreAllWindowsSubview.label");
-      separator = doc.getElementById("PanelUI-recentlyClosedWindows-separator");
-      elementCount = windowsFragment.childElementCount;
-      separator.hidden = !elementCount;
-      while (--elementCount >= 0) {
-        windowsFragment.children[elementCount].classList.add("subviewbutton", "cui-withicon");
-      }
-      recentlyClosedWindows.appendChild(windowsFragment);
-    },
-    onCreated: function(aNode) {
-      // Middle clicking recently closed items won't close the panel - cope:
-      let onRecentlyClosedClick = function(aEvent) {
-        if (aEvent.button == 1) {
-          CustomizableUI.hidePanelForNode(this);
-        }
-      };
-      let doc = aNode.ownerDocument;
-      let recentlyClosedTabs = doc.getElementById("PanelUI-recentlyClosedTabs");
-      let recentlyClosedWindows = doc.getElementById("PanelUI-recentlyClosedWindows");
-      recentlyClosedTabs.addEventListener("click", onRecentlyClosedClick);
-      recentlyClosedWindows.addEventListener("click", onRecentlyClosedClick);
-    },
-    onViewHiding: function(aEvent) {
-      log.debug("History view is being hidden!");
-    }
-  }, {
-    id: "sync-button",
-    label: "remotetabs-panelmenu.label",
-    tooltiptext: "remotetabs-panelmenu.tooltiptext2",
-    type: "view",
-    viewId: "PanelUI-remotetabs",
-    defaultArea: CustomizableUI.AREA_PANEL,
-    deckIndices: {
-      DECKINDEX_TABS: 0,
-      DECKINDEX_TABSDISABLED: 1,
-      DECKINDEX_FETCHING: 2,
-      DECKINDEX_NOCLIENTS: 3,
-    },
-    onCreated(aNode) {
-      // Add an observer to the button so we get the animation during sync.
-      // (Note the observer sets many attributes, including label and
-      // tooltiptext, but we only want the 'syncstatus' attribute for the
-      // animation)
-      let doc = aNode.ownerDocument;
-      let obnode = doc.createElementNS(kNSXUL, "observes");
-      obnode.setAttribute("element", "sync-status");
-      obnode.setAttribute("attribute", "syncstatus");
-      aNode.appendChild(obnode);
-
-      // A somewhat complicated dance to format the mobilepromo label.
-      let bundle = doc.getElementById("bundle_browser");
-      let formatArgs = ["android", "ios"].map(os => {
-        let link = doc.createElement("label");
-        link.textContent = bundle.getString(`appMenuRemoteTabs.mobilePromo.${os}`);
-        link.setAttribute("mobile-promo-os", os);
-        link.className = "text-link remotetabs-promo-link";
-        return link.outerHTML;
-      });
-      let promoParentElt = doc.getElementById("PanelUI-remotetabs-mobile-promo");
-      // Put it all together...
-      let contents = bundle.getFormattedString("appMenuRemoteTabs.mobilePromo.text2", formatArgs);
-      promoParentElt.innerHTML = contents;
-      // We manually manage the "click" event to open the promo links because
-      // allowing the "text-link" widget handle it has 2 problems: (1) it only
-      // supports button 0 and (2) it's tricky to intercept when it does the
-      // open and auto-close the panel. (1) can probably be fixed, but (2) is
-      // trickier without hard-coding here the knowledge of exactly what buttons
-      // it does support.
-      // So we allow left and middle clicks to open the link in a new tab and
-      // close the panel; not setting a "href" attribute prevents the text-link
-      // widget handling it, and we build the final URL in the click handler to
-      // make testing easier (ie, so tests can change the pref after the links
-      // were created and have the new pref value used.)
-      promoParentElt.addEventListener("click", e => {
-        let os = e.target.getAttribute("mobile-promo-os");
-        if (!os || e.button > 1) {
-          return;
-        }
-        let link = Services.prefs.getCharPref(`identity.mobilepromo.${os}`) + "synced-tabs";
-        doc.defaultView.openUILinkIn(link, "tab");
-        CustomizableUI.hidePanelForNode(e.target);
-      });
-    },
-    onViewShowing(aEvent) {
-      let doc = aEvent.target.ownerDocument;
-      this._tabsList = doc.getElementById("PanelUI-remotetabs-tabslist");
-      Services.obs.addObserver(this, SyncedTabs.TOPIC_TABS_CHANGED, false);
-
-      if (SyncedTabs.isConfiguredToSyncTabs) {
-        if (SyncedTabs.hasSyncedThisSession) {
-          this.setDeckIndex(this.deckIndices.DECKINDEX_TABS);
-        } else {
-          // Sync hasn't synced tabs yet, so show the "fetching" panel.
-          this.setDeckIndex(this.deckIndices.DECKINDEX_FETCHING);
-        }
-        // force a background sync.
-        SyncedTabs.syncTabs().catch(ex => {
-          Cu.reportError(ex);
-        });
-        // show the current list - it will be updated by our observer.
-        this._showTabs();
-      } else {
-        // not configured to sync tabs, so no point updating the list.
-        this.setDeckIndex(this.deckIndices.DECKINDEX_TABSDISABLED);
-      }
-    },
-    onViewHiding() {
-      Services.obs.removeObserver(this, SyncedTabs.TOPIC_TABS_CHANGED);
-      this._tabsList = null;
-    },
-    _tabsList: null,
-    observe(subject, topic, data) {
-      switch (topic) {
-        case SyncedTabs.TOPIC_TABS_CHANGED:
-          this._showTabs();
-          break;
-        default:
-          break;
-      }
-    },
-    setDeckIndex(index) {
-      let deck = this._tabsList.ownerDocument.getElementById("PanelUI-remotetabs-deck");
-      // We call setAttribute instead of relying on the XBL property setter due
-      // to things going wrong when we try and set the index before the XBL
-      // binding has been created - see bug 1241851 for the gory details.
-      deck.setAttribute("selectedIndex", index);
-    },
-
-    _showTabsPromise: Promise.resolve(),
-    // Update the tab list after any existing in-flight updates are complete.
-    _showTabs() {
-      this._showTabsPromise = this._showTabsPromise.then(() => {
-        return this.__showTabs();
-      });
-    },
-    // Return a new promise to update the tab list.
-    __showTabs() {
-      let doc = this._tabsList.ownerDocument;
-      return SyncedTabs.getTabClients().then(clients => {
-        // The view may have been hidden while the promise was resolving.
-        if (!this._tabsList) {
-          return;
-        }
-        if (clients.length === 0 && !SyncedTabs.hasSyncedThisSession) {
-          // the "fetching tabs" deck is being shown - let's leave it there.
-          // When that first sync completes we'll be notified and update.
-          return;
-        }
-
-        if (clients.length === 0) {
-          this.setDeckIndex(this.deckIndices.DECKINDEX_NOCLIENTS);
-          return;
-        }
-
-        this.setDeckIndex(this.deckIndices.DECKINDEX_TABS);
-        this._clearTabList();
-        SyncedTabs.sortTabClientsByLastUsed(clients, 50 /* maxTabs */);
-        let fragment = doc.createDocumentFragment();
-
-        for (let client of clients) {
-          // add a menu separator for all clients other than the first.
-          if (fragment.lastChild) {
-            let separator = doc.createElementNS(kNSXUL, "menuseparator");
-            fragment.appendChild(separator);
-          }
-          this._appendClient(client, fragment);
-        }
-        this._tabsList.appendChild(fragment);
-      }).catch(err => {
-        Cu.reportError(err);
-      }).then(() => {
-        // an observer for tests.
-        Services.obs.notifyObservers(null, "synced-tabs-menu:test:tabs-updated", null);
-      });
-    },
-    _clearTabList () {
-      let list = this._tabsList;
-      while (list.lastChild) {
-        list.lastChild.remove();
-      }
-    },
-    _showNoClientMessage() {
-      this._appendMessageLabel("notabslabel");
-    },
-    _appendMessageLabel(messageAttr, appendTo = null) {
-      if (!appendTo) {
-        appendTo = this._tabsList;
-      }
-      let message = this._tabsList.getAttribute(messageAttr);
-      let doc = this._tabsList.ownerDocument;
-      let messageLabel = doc.createElementNS(kNSXUL, "label");
-      messageLabel.textContent = message;
-      appendTo.appendChild(messageLabel);
-      return messageLabel;
-    },
-    _appendClient: function (client, attachFragment) {
-      let doc = attachFragment.ownerDocument;
-      // Create the element for the remote client.
-      let clientItem = doc.createElementNS(kNSXUL, "label");
-      clientItem.setAttribute("itemtype", "client");
-      let window = doc.defaultView;
-      clientItem.setAttribute("tooltiptext",
-        window.gSyncUI.formatLastSyncDate(new Date(client.lastModified)));
-      clientItem.textContent = client.name;
-
-      attachFragment.appendChild(clientItem);
-
-      if (client.tabs.length == 0) {
-        let label = this._appendMessageLabel("notabsforclientlabel", attachFragment);
-        label.setAttribute("class", "PanelUI-remotetabs-notabsforclient-label");
-      } else {
-        for (let tab of client.tabs) {
-          let tabEnt = this._createTabElement(doc, tab);
-          attachFragment.appendChild(tabEnt);
-        }
-      }
-    },
-    _createTabElement(doc, tabInfo) {
-      let item = doc.createElementNS(kNSXUL, "toolbarbutton");
-      let tooltipText = (tabInfo.title ? tabInfo.title + "\n" : "") + tabInfo.url;
-      item.setAttribute("itemtype", "tab");
-      item.setAttribute("class", "subviewbutton");
-      item.setAttribute("targetURI", tabInfo.url);
-      item.setAttribute("label", tabInfo.title != "" ? tabInfo.title : tabInfo.url);
-      item.setAttribute("image", tabInfo.icon);
-      item.setAttribute("tooltiptext", tooltipText);
-      // We need to use "click" instead of "command" here so openUILink
-      // respects different buttons (eg, to open in a new tab).
-      item.addEventListener("click", e => {
-        doc.defaultView.openUILink(tabInfo.url, e);
-        CustomizableUI.hidePanelForNode(item);
-        BrowserUITelemetry.countSyncedTabEvent("open", "toolbarbutton-subview");
-      });
-      return item;
-    },
-  }, {
-    id: "privatebrowsing-button",
-    shortcutId: "key_privatebrowsing",
-    defaultArea: CustomizableUI.AREA_PANEL,
-    onCommand: function(e) {
-      let win = e.target.ownerGlobal;
-      win.OpenBrowserWindow({private: true});
-    }
-  }, {
-    id: "save-page-button",
-    shortcutId: "key_savePage",
-    tooltiptext: "save-page-button.tooltiptext3",
-    defaultArea: CustomizableUI.AREA_PANEL,
-    onCommand: function(aEvent) {
-      let win = aEvent.target.ownerGlobal;
-      win.saveBrowser(win.gBrowser.selectedBrowser);
-    }
-  }, {
-    id: "find-button",
-    shortcutId: "key_find",
-    tooltiptext: "find-button.tooltiptext3",
-    defaultArea: CustomizableUI.AREA_PANEL,
-    onCommand: function(aEvent) {
-      let win = aEvent.target.ownerGlobal;
-      if (win.gFindBar) {
-        win.gFindBar.onFindCommand();
-      }
-    }
-  }, {
-    id: "open-file-button",
-    shortcutId: "openFileKb",
-    tooltiptext: "open-file-button.tooltiptext3",
-    defaultArea: CustomizableUI.AREA_PANEL,
-    onCommand: function(aEvent) {
-      let win = aEvent.target.ownerGlobal;
-      win.BrowserOpenFileWindow();
-    }
-  }, {
-    id: "sidebar-button",
-    type: "view",
-    viewId: "PanelUI-sidebar",
-    tooltiptext: "sidebar-button.tooltiptext2",
-    onViewShowing: function(aEvent) {
-      // Populate the subview with whatever menuitems are in the
-      // sidebar menu. We skip menu elements, because the menu panel has no way
-      // of dealing with those right now.
-      let doc = aEvent.target.ownerDocument;
-      let menu = doc.getElementById("viewSidebarMenu");
-
-      // First clear any existing menuitems then populate. Add it to the
-      // standard menu first, then copy all sidebar options to the panel.
-      let sidebarItems = doc.getElementById("PanelUI-sidebarItems");
-      clearSubview(sidebarItems);
-      fillSubviewFromMenuItems([...menu.children], sidebarItems);
-    }
-  }, {
-    id: "add-ons-button",
-    shortcutId: "key_openAddons",
-    tooltiptext: "add-ons-button.tooltiptext3",
-    defaultArea: CustomizableUI.AREA_PANEL,
-    onCommand: function(aEvent) {
-      let win = aEvent.target.ownerGlobal;
-      win.BrowserOpenAddonsMgr();
-    }
-  }, {
-    id: "zoom-controls",
-    type: "custom",
-    tooltiptext: "zoom-controls.tooltiptext2",
-    defaultArea: CustomizableUI.AREA_PANEL,
-    onBuild: function(aDocument) {
-      const kPanelId = "PanelUI-popup";
-      let areaType = CustomizableUI.getAreaType(this.currentArea);
-      let inPanel = areaType == CustomizableUI.TYPE_MENU_PANEL;
-      let inToolbar = areaType == CustomizableUI.TYPE_TOOLBAR;
-
-      let buttons = [{
-        id: "zoom-out-button",
-        command: "cmd_fullZoomReduce",
-        label: true,
-        tooltiptext: "tooltiptext2",
-        shortcutId: "key_fullZoomReduce",
-      }, {
-        id: "zoom-reset-button",
-        command: "cmd_fullZoomReset",
-        tooltiptext: "tooltiptext2",
-        shortcutId: "key_fullZoomReset",
-      }, {
-        id: "zoom-in-button",
-        command: "cmd_fullZoomEnlarge",
-        label: true,
-        tooltiptext: "tooltiptext2",
-        shortcutId: "key_fullZoomEnlarge",
-      }];
-
-      let node = aDocument.createElementNS(kNSXUL, "toolbaritem");
-      node.setAttribute("id", "zoom-controls");
-      node.setAttribute("label", CustomizableUI.getLocalizedProperty(this, "label"));
-      node.setAttribute("title", CustomizableUI.getLocalizedProperty(this, "tooltiptext"));
-      // Set this as an attribute in addition to the property to make sure we can style correctly.
-      node.setAttribute("removable", "true");
-      node.classList.add("chromeclass-toolbar-additional");
-      node.classList.add("toolbaritem-combined-buttons");
-      node.classList.add(kWidePanelItemClass);
-
-      buttons.forEach(function(aButton, aIndex) {
-        if (aIndex != 0)
-          node.appendChild(aDocument.createElementNS(kNSXUL, "separator"));
-        let btnNode = aDocument.createElementNS(kNSXUL, "toolbarbutton");
-        setAttributes(btnNode, aButton);
-        node.appendChild(btnNode);
-      });
-
-      // The middle node is the 'Reset Zoom' button.
-      let zoomResetButton = node.childNodes[2];
-      let window = aDocument.defaultView;
-      function updateZoomResetButton() {
-        let updateDisplay = true;
-        // Label should always show 100% in customize mode, so don't update:
-        if (aDocument.documentElement.hasAttribute("customizing")) {
-          updateDisplay = false;
-        }
-        // XXXgijs in some tests we get called very early, and there's no docShell on the
-        // tabbrowser. This breaks the zoom toolkit code (see bug 897410). Don't let that happen:
-        let zoomFactor = 100;
-        try {
-          zoomFactor = Math.round(window.ZoomManager.zoom * 100);
-        } catch (e) {}
-        zoomResetButton.setAttribute("label", CustomizableUI.getLocalizedProperty(
-          buttons[1], "label", [updateDisplay ? zoomFactor : 100]
-        ));
-      }
-
-      // Register ourselves with the service so we know when the zoom prefs change.
-      Services.obs.addObserver(updateZoomResetButton, "browser-fullZoom:zoomChange", false);
-      Services.obs.addObserver(updateZoomResetButton, "browser-fullZoom:zoomReset", false);
-      Services.obs.addObserver(updateZoomResetButton, "browser-fullZoom:location-change", false);
-
-      if (inPanel) {
-        let panel = aDocument.getElementById(kPanelId);
-        panel.addEventListener("popupshowing", updateZoomResetButton);
-      } else {
-        if (inToolbar) {
-          let container = window.gBrowser.tabContainer;
-          container.addEventListener("TabSelect", updateZoomResetButton);
-        }
-        updateZoomResetButton();
-      }
-      updateCombinedWidgetStyle(node, this.currentArea, true);
-
-      let listener = {
-        onWidgetAdded: function(aWidgetId, aArea, aPosition) {
-          if (aWidgetId != this.id)
-            return;
-
-          updateCombinedWidgetStyle(node, aArea, true);
-          updateZoomResetButton();
-
-          let areaType = CustomizableUI.getAreaType(aArea);
-          if (areaType == CustomizableUI.TYPE_MENU_PANEL) {
-            let panel = aDocument.getElementById(kPanelId);
-            panel.addEventListener("popupshowing", updateZoomResetButton);
-          } else if (areaType == CustomizableUI.TYPE_TOOLBAR) {
-            let container = window.gBrowser.tabContainer;
-            container.addEventListener("TabSelect", updateZoomResetButton);
-          }
-        }.bind(this),
-
-        onWidgetRemoved: function(aWidgetId, aPrevArea) {
-          if (aWidgetId != this.id)
-            return;
-
-          let areaType = CustomizableUI.getAreaType(aPrevArea);
-          if (areaType == CustomizableUI.TYPE_MENU_PANEL) {
-            let panel = aDocument.getElementById(kPanelId);
-            panel.removeEventListener("popupshowing", updateZoomResetButton);
-          } else if (areaType == CustomizableUI.TYPE_TOOLBAR) {
-            let container = window.gBrowser.tabContainer;
-            container.removeEventListener("TabSelect", updateZoomResetButton);
-          }
-
-          // When a widget is demoted to the palette ('removed'), it's visual
-          // style should change.
-          updateCombinedWidgetStyle(node, null, true);
-          updateZoomResetButton();
-        }.bind(this),
-
-        onWidgetReset: function(aWidgetNode) {
-          if (aWidgetNode != node)
-            return;
-          updateCombinedWidgetStyle(node, this.currentArea, true);
-          updateZoomResetButton();
-        }.bind(this),
-
-        onWidgetUndoMove: function(aWidgetNode) {
-          if (aWidgetNode != node)
-            return;
-          updateCombinedWidgetStyle(node, this.currentArea, true);
-          updateZoomResetButton();
-        }.bind(this),
-
-        onWidgetMoved: function(aWidgetId, aArea) {
-          if (aWidgetId != this.id)
-            return;
-          updateCombinedWidgetStyle(node, aArea, true);
-          updateZoomResetButton();
-        }.bind(this),
-
-        onWidgetInstanceRemoved: function(aWidgetId, aDoc) {
-          if (aWidgetId != this.id || aDoc != aDocument)
-            return;
-
-          CustomizableUI.removeListener(listener);
-          Services.obs.removeObserver(updateZoomResetButton, "browser-fullZoom:zoomChange");
-          Services.obs.removeObserver(updateZoomResetButton, "browser-fullZoom:zoomReset");
-          Services.obs.removeObserver(updateZoomResetButton, "browser-fullZoom:location-change");
-          let panel = aDoc.getElementById(kPanelId);
-          panel.removeEventListener("popupshowing", updateZoomResetButton);
-          let container = aDoc.defaultView.gBrowser.tabContainer;
-          container.removeEventListener("TabSelect", updateZoomResetButton);
-        }.bind(this),
-
-        onCustomizeStart: function(aWindow) {
-          if (aWindow.document == aDocument) {
-            updateZoomResetButton();
-          }
-        },
-
-        onCustomizeEnd: function(aWindow) {
-          if (aWindow.document == aDocument) {
-            updateZoomResetButton();
-          }
-        },
-
-        onWidgetDrag: function(aWidgetId, aArea) {
-          if (aWidgetId != this.id)
-            return;
-          aArea = aArea || this.currentArea;
-          updateCombinedWidgetStyle(node, aArea, true);
-        }.bind(this)
-      };
-      CustomizableUI.addListener(listener);
-
-      return node;
-    }
-  }, {
-    id: "edit-controls",
-    type: "custom",
-    tooltiptext: "edit-controls.tooltiptext2",
-    defaultArea: CustomizableUI.AREA_PANEL,
-    onBuild: function(aDocument) {
-      let buttons = [{
-        id: "cut-button",
-        command: "cmd_cut",
-        label: true,
-        tooltiptext: "tooltiptext2",
-        shortcutId: "key_cut",
-      }, {
-        id: "copy-button",
-        command: "cmd_copy",
-        label: true,
-        tooltiptext: "tooltiptext2",
-        shortcutId: "key_copy",
-      }, {
-        id: "paste-button",
-        command: "cmd_paste",
-        label: true,
-        tooltiptext: "tooltiptext2",
-        shortcutId: "key_paste",
-      }];
-
-      let node = aDocument.createElementNS(kNSXUL, "toolbaritem");
-      node.setAttribute("id", "edit-controls");
-      node.setAttribute("label", CustomizableUI.getLocalizedProperty(this, "label"));
-      node.setAttribute("title", CustomizableUI.getLocalizedProperty(this, "tooltiptext"));
-      // Set this as an attribute in addition to the property to make sure we can style correctly.
-      node.setAttribute("removable", "true");
-      node.classList.add("chromeclass-toolbar-additional");
-      node.classList.add("toolbaritem-combined-buttons");
-      node.classList.add(kWidePanelItemClass);
-
-      buttons.forEach(function(aButton, aIndex) {
-        if (aIndex != 0)
-          node.appendChild(aDocument.createElementNS(kNSXUL, "separator"));
-        let btnNode = aDocument.createElementNS(kNSXUL, "toolbarbutton");
-        setAttributes(btnNode, aButton);
-        node.appendChild(btnNode);
-      });
-
-      updateCombinedWidgetStyle(node, this.currentArea);
-
-      let listener = {
-        onWidgetAdded: function(aWidgetId, aArea, aPosition) {
-          if (aWidgetId != this.id)
-            return;
-          updateCombinedWidgetStyle(node, aArea);
-        }.bind(this),
-
-        onWidgetRemoved: function(aWidgetId, aPrevArea) {
-          if (aWidgetId != this.id)
-            return;
-          // When a widget is demoted to the palette ('removed'), it's visual
-          // style should change.
-          updateCombinedWidgetStyle(node);
-        }.bind(this),
-
-        onWidgetReset: function(aWidgetNode) {
-          if (aWidgetNode != node)
-            return;
-          updateCombinedWidgetStyle(node, this.currentArea);
-        }.bind(this),
-
-        onWidgetUndoMove: function(aWidgetNode) {
-          if (aWidgetNode != node)
-            return;
-          updateCombinedWidgetStyle(node, this.currentArea);
-        }.bind(this),
-
-        onWidgetMoved: function(aWidgetId, aArea) {
-          if (aWidgetId != this.id)
-            return;
-          updateCombinedWidgetStyle(node, aArea);
-        }.bind(this),
-
-        onWidgetInstanceRemoved: function(aWidgetId, aDoc) {
-          if (aWidgetId != this.id || aDoc != aDocument)
-            return;
-          CustomizableUI.removeListener(listener);
-        }.bind(this),
-
-        onWidgetDrag: function(aWidgetId, aArea) {
-          if (aWidgetId != this.id)
-            return;
-          aArea = aArea || this.currentArea;
-          updateCombinedWidgetStyle(node, aArea);
-        }.bind(this)
-      };
-      CustomizableUI.addListener(listener);
-
-      return node;
-    }
-  },
-  {
-    id: "feed-button",
-    type: "view",
-    viewId: "PanelUI-feeds",
-    tooltiptext: "feed-button.tooltiptext2",
-    defaultArea: CustomizableUI.AREA_PANEL,
-    onClick: function(aEvent) {
-      let win = aEvent.target.ownerGlobal;
-      let feeds = win.gBrowser.selectedBrowser.feeds;
-
-      // Here, we only care about the case where we have exactly 1 feed and the
-      // user clicked...
-      let isClick = (aEvent.button == 0 || aEvent.button == 1);
-      if (feeds && feeds.length == 1 && isClick) {
-        aEvent.preventDefault();
-        aEvent.stopPropagation();
-        win.FeedHandler.subscribeToFeed(feeds[0].href, aEvent);
-        CustomizableUI.hidePanelForNode(aEvent.target);
-      }
-    },
-    onViewShowing: function(aEvent) {
-      let doc = aEvent.target.ownerDocument;
-      let container = doc.getElementById("PanelUI-feeds");
-      let gotView = doc.defaultView.FeedHandler.buildFeedList(container, true);
-
-      // For no feeds or only a single one, don't show the panel.
-      if (!gotView) {
-        aEvent.preventDefault();
-        aEvent.stopPropagation();
-        return;
-      }
-    },
-    onCreated: function(node) {
-      let win = node.ownerGlobal;
-      let selectedBrowser = win.gBrowser.selectedBrowser;
-      let feeds = selectedBrowser && selectedBrowser.feeds;
-      if (!feeds || !feeds.length) {
-        node.setAttribute("disabled", "true");
-      }
-    }
-  }, {
-    id: "characterencoding-button",
-    label: "characterencoding-button2.label",
-    type: "view",
-    viewId: "PanelUI-characterEncodingView",
-    tooltiptext: "characterencoding-button2.tooltiptext",
-    defaultArea: CustomizableUI.AREA_PANEL,
-    maybeDisableMenu: function(aDocument) {
-      let window = aDocument.defaultView;
-      return !(window.gBrowser &&
-               window.gBrowser.selectedBrowser.mayEnableCharacterEncodingMenu);
-    },
-    populateList: function(aDocument, aContainerId, aSection) {
-      let containerElem = aDocument.getElementById(aContainerId);
-
-      containerElem.addEventListener("command", this.onCommand, false);
-
-      let list = this.charsetInfo[aSection];
-
-      for (let item of list) {
-        let elem = aDocument.createElementNS(kNSXUL, "toolbarbutton");
-        elem.setAttribute("label", item.label);
-        elem.setAttribute("type", "checkbox");
-        elem.section = aSection;
-        elem.value = item.value;
-        elem.setAttribute("class", "subviewbutton");
-        containerElem.appendChild(elem);
-      }
-    },
-    updateCurrentCharset: function(aDocument) {
-      let currentCharset = aDocument.defaultView.gBrowser.selectedBrowser.characterSet;
-      currentCharset = CharsetMenu.foldCharset(currentCharset);
-
-      let pinnedContainer = aDocument.getElementById("PanelUI-characterEncodingView-pinned");
-      let charsetContainer = aDocument.getElementById("PanelUI-characterEncodingView-charsets");
-      let elements = [...(pinnedContainer.childNodes), ...(charsetContainer.childNodes)];
-
-      this._updateElements(elements, currentCharset);
-    },
-    updateCurrentDetector: function(aDocument) {
-      let detectorContainer = aDocument.getElementById("PanelUI-characterEncodingView-autodetect");
-      let currentDetector;
-      try {
-        currentDetector = Services.prefs.getComplexValue(
-          "intl.charset.detector", Ci.nsIPrefLocalizedString).data;
-      } catch (e) {}
-
-      this._updateElements(detectorContainer.childNodes, currentDetector);
-    },
-    _updateElements: function(aElements, aCurrentItem) {
-      if (!aElements.length) {
-        return;
-      }
-      let disabled = this.maybeDisableMenu(aElements[0].ownerDocument);
-      for (let elem of aElements) {
-        if (disabled) {
-          elem.setAttribute("disabled", "true");
-        } else {
-          elem.removeAttribute("disabled");
-        }
-        if (elem.value.toLowerCase() == aCurrentItem.toLowerCase()) {
-          elem.setAttribute("checked", "true");
-        } else {
-          elem.removeAttribute("checked");
-        }
-      }
-    },
-    onViewShowing: function(aEvent) {
-      let document = aEvent.target.ownerDocument;
-
-      let autoDetectLabelId = "PanelUI-characterEncodingView-autodetect-label";
-      let autoDetectLabel = document.getElementById(autoDetectLabelId);
-      if (!autoDetectLabel.hasAttribute("value")) {
-        let label = CharsetBundle.GetStringFromName("charsetMenuAutodet");
-        autoDetectLabel.setAttribute("value", label);
-        this.populateList(document,
-                          "PanelUI-characterEncodingView-pinned",
-                          "pinnedCharsets");
-        this.populateList(document,
-                          "PanelUI-characterEncodingView-charsets",
-                          "otherCharsets");
-        this.populateList(document,
-                          "PanelUI-characterEncodingView-autodetect",
-                          "detectors");
-      }
-      this.updateCurrentDetector(document);
-      this.updateCurrentCharset(document);
-    },
-    onCommand: function(aEvent) {
-      let node = aEvent.target;
-      if (!node.hasAttribute || !node.section) {
-        return;
-      }
-
-      let window = node.ownerGlobal;
-      let section = node.section;
-      let value = node.value;
-
-      // The behavior as implemented here is directly based off of the
-      // `MultiplexHandler()` method in browser.js.
-      if (section != "detectors") {
-        window.BrowserSetForcedCharacterSet(value);
-      } else {
-        // Set the detector pref.
-        try {
-          let str = Cc["@mozilla.org/supports-string;1"]
-                      .createInstance(Ci.nsISupportsString);
-          str.data = value;
-          Services.prefs.setComplexValue("intl.charset.detector", Ci.nsISupportsString, str);
-        } catch (e) {
-          Cu.reportError("Failed to set the intl.charset.detector preference.");
-        }
-        // Prepare a browser page reload with a changed charset.
-        window.BrowserCharsetReload();
-      }
-    },
-    onCreated: function(aNode) {
-      const kPanelId = "PanelUI-popup";
-      let document = aNode.ownerDocument;
-
-      let updateButton = () => {
-        if (this.maybeDisableMenu(document))
-          aNode.setAttribute("disabled", "true");
-        else
-          aNode.removeAttribute("disabled");
-      };
-
-      if (this.currentArea == CustomizableUI.AREA_PANEL) {
-        let panel = document.getElementById(kPanelId);
-        panel.addEventListener("popupshowing", updateButton);
-      }
-
-      let listener = {
-        onWidgetAdded: (aWidgetId, aArea) => {
-          if (aWidgetId != this.id)
-            return;
-          if (aArea == CustomizableUI.AREA_PANEL) {
-            let panel = document.getElementById(kPanelId);
-            panel.addEventListener("popupshowing", updateButton);
-          }
-        },
-        onWidgetRemoved: (aWidgetId, aPrevArea) => {
-          if (aWidgetId != this.id)
-            return;
-          aNode.removeAttribute("disabled");
-          if (aPrevArea == CustomizableUI.AREA_PANEL) {
-            let panel = document.getElementById(kPanelId);
-            panel.removeEventListener("popupshowing", updateButton);
-          }
-        },
-        onWidgetInstanceRemoved: (aWidgetId, aDoc) => {
-          if (aWidgetId != this.id || aDoc != document)
-            return;
-
-          CustomizableUI.removeListener(listener);
-          let panel = aDoc.getElementById(kPanelId);
-          panel.removeEventListener("popupshowing", updateButton);
-        }
-      };
-      CustomizableUI.addListener(listener);
-      if (!this.charsetInfo) {
-        this.charsetInfo = CharsetMenu.getData();
-      }
-    }
-  }, {
-    id: "email-link-button",
-    tooltiptext: "email-link-button.tooltiptext3",
-    onCommand: function(aEvent) {
-      let win = aEvent.view;
-      win.MailIntegration.sendLinkForBrowser(win.gBrowser.selectedBrowser)
-    }
-  }, {
-    id: "containers-panelmenu",
-    type: "view",
-    viewId: "PanelUI-containers",
-    hasObserver: false,
-    onCreated: function(aNode) {
-      let doc = aNode.ownerDocument;
-      let win = doc.defaultView;
-      let items = doc.getElementById("PanelUI-containersItems");
-
-      let onItemCommand = function (aEvent) {
-        let item = aEvent.target;
-        if (item.hasAttribute("usercontextid")) {
-          let userContextId = parseInt(item.getAttribute("usercontextid"));
-          win.openUILinkIn(win.BROWSER_NEW_TAB_URL, "tab", {userContextId});
-        }
-      };
-      items.addEventListener("command", onItemCommand);
-
-      if (PrivateBrowsingUtils.isWindowPrivate(win)) {
-        aNode.setAttribute("disabled", "true");
-      }
-
-      this.updateVisibility(aNode);
-
-      if (!this.hasObserver) {
-        Services.prefs.addObserver("privacy.userContext.enabled", this, true);
-        this.hasObserver = true;
-      }
-    },
-    onViewShowing: function(aEvent) {
-      let doc = aEvent.target.ownerDocument;
-
-      let items = doc.getElementById("PanelUI-containersItems");
-
-      while (items.firstChild) {
-        items.firstChild.remove();
-      }
-
-      let fragment = doc.createDocumentFragment();
-      let bundle = doc.getElementById("bundle_browser");
-
-      ContextualIdentityService.getIdentities().forEach(identity => {
-        let label = ContextualIdentityService.getUserContextLabel(identity.userContextId);
-
-        let item = doc.createElementNS(kNSXUL, "toolbarbutton");
-        item.setAttribute("label", label);
-        item.setAttribute("usercontextid", identity.userContextId);
-        item.setAttribute("class", "subviewbutton");
-        item.setAttribute("data-identity-color", identity.color);
-        item.setAttribute("data-identity-icon", identity.icon);
-
-        fragment.appendChild(item);
-      });
-
-      fragment.appendChild(doc.createElementNS(kNSXUL, "menuseparator"));
-
-      let item = doc.createElementNS(kNSXUL, "toolbarbutton");
-      item.setAttribute("label", bundle.getString("userContext.aboutPage.label"));
-      item.setAttribute("command", "Browser:OpenAboutContainers");
-      item.setAttribute("class", "subviewbutton");
-      fragment.appendChild(item);
-
-      items.appendChild(fragment);
-    },
-
-    updateVisibility(aNode) {
-      aNode.hidden = !Services.prefs.getBoolPref("privacy.userContext.enabled");
-    },
-
-    observe(aSubject, aTopic, aData) {
-      let {instances} = CustomizableUI.getWidget("containers-panelmenu");
-      for (let {node} of instances) {
-	if (node) {
-	  this.updateVisibility(node);
-	}
-      }
-    },
-
-    QueryInterface: XPCOMUtils.generateQI([
-      Ci.nsISupportsWeakReference,
-      Ci.nsIObserver
-    ]),
-  }];
-
-let preferencesButton = {
-  id: "preferences-button",
-  defaultArea: CustomizableUI.AREA_PANEL,
-  onCommand: function(aEvent) {
-    let win = aEvent.target.ownerGlobal;
-    win.openPreferences();
-  }
-};
-if (AppConstants.platform == "macosx") {
-  preferencesButton.tooltiptext = "preferences-button.tooltiptext.withshortcut";
-  preferencesButton.shortcutId = "key_preferencesCmdMac";
-} else {
-  preferencesButton.tooltiptext = "preferences-button.tooltiptext2";
-}
-CustomizableWidgets.push(preferencesButton);
-
-if (Services.prefs.getBoolPref("privacy.panicButton.enabled")) {
-  CustomizableWidgets.push({
-    id: "panic-button",
-    type: "view",
-    viewId: "PanelUI-panicView",
-    _sanitizer: null,
-    _ensureSanitizer: function() {
-      if (!this.sanitizer) {
-        let scope = {};
-        Services.scriptloader.loadSubScript("chrome://browser/content/sanitize.js",
-                                            scope);
-        this._Sanitizer = scope.Sanitizer;
-        this._sanitizer = new scope.Sanitizer();
-        this._sanitizer.ignoreTimespan = false;
-      }
-    },
-    _getSanitizeRange: function(aDocument) {
-      let group = aDocument.getElementById("PanelUI-panic-timeSpan");
-      return this._Sanitizer.getClearRange(+group.value);
-    },
-    forgetButtonCalled: function(aEvent) {
-      let doc = aEvent.target.ownerDocument;
-      this._ensureSanitizer();
-      this._sanitizer.range = this._getSanitizeRange(doc);
-      let group = doc.getElementById("PanelUI-panic-timeSpan");
-      BrowserUITelemetry.countPanicEvent(group.selectedItem.id);
-      group.selectedItem = doc.getElementById("PanelUI-panic-5min");
-      let itemsToClear = [
-        "cookies", "history", "openWindows", "formdata", "sessions", "cache", "downloads"
-      ];
-      let newWindowPrivateState = PrivateBrowsingUtils.isWindowPrivate(doc.defaultView) ?
-                                  "private" : "non-private";
-      this._sanitizer.items.openWindows.privateStateForNewWindow = newWindowPrivateState;
-      let promise = this._sanitizer.sanitize(itemsToClear);
-      promise.then(function() {
-        let otherWindow = Services.wm.getMostRecentWindow("navigator:browser");
-        if (otherWindow.closed) {
-          Cu.reportError("Got a closed window!");
-        }
-        if (otherWindow.PanicButtonNotifier) {
-          otherWindow.PanicButtonNotifier.notify();
-        } else {
-          otherWindow.PanicButtonNotifierShouldNotify = true;
-        }
-      });
-    },
-    handleEvent: function(aEvent) {
-      switch (aEvent.type) {
-        case "command":
-          this.forgetButtonCalled(aEvent);
-          break;
-      }
-    },
-    onViewShowing: function(aEvent) {
-      let forgetButton = aEvent.target.querySelector("#PanelUI-panic-view-button");
-      forgetButton.addEventListener("command", this);
-    },
-    onViewHiding: function(aEvent) {
-      let forgetButton = aEvent.target.querySelector("#PanelUI-panic-view-button");
-      forgetButton.removeEventListener("command", this);
-    },
-  });
-}
diff --git a/browser/components/customizableui/CustomizeMode.jsm b/browser/components/customizableui/CustomizeMode.jsm
deleted file mode 100644
index e63e25b0a..000000000
--- a/browser/components/customizableui/CustomizeMode.jsm
+++ /dev/null
@@ -1,2297 +0,0 @@
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-"use strict";
-
-this.EXPORTED_SYMBOLS = ["CustomizeMode"];
-
-const {classes: Cc, interfaces: Ci, utils: Cu, results: Cr} = Components;
-
-const kPrefCustomizationDebug = "browser.uiCustomization.debug";
-const kPrefCustomizationAnimation = "browser.uiCustomization.disableAnimation";
-const kPaletteId = "customization-palette";
-const kDragDataTypePrefix = "text/toolbarwrapper-id/";
-const kPlaceholderClass = "panel-customization-placeholder";
-const kSkipSourceNodePref = "browser.uiCustomization.skipSourceNodeCheck";
-const kToolbarVisibilityBtn = "customization-toolbar-visibility-button";
-const kDrawInTitlebarPref = "browser.tabs.drawInTitlebar";
-const kMaxTransitionDurationMs = 2000;
-
-const kPanelItemContextMenu = "customizationPanelItemContextMenu";
-const kPaletteItemContextMenu = "customizationPaletteItemContextMenu";
-
-Cu.import("resource://gre/modules/Services.jsm");
-Cu.import("resource:///modules/CustomizableUI.jsm");
-Cu.import("resource://gre/modules/XPCOMUtils.jsm");
-Cu.import("resource://gre/modules/Task.jsm");
-Cu.import("resource://gre/modules/Promise.jsm");
-Cu.import("resource://gre/modules/AddonManager.jsm");
-Cu.import("resource://gre/modules/AppConstants.jsm");
-
-XPCOMUtils.defineLazyModuleGetter(this, "DragPositionManager",
-                                  "resource:///modules/DragPositionManager.jsm");
-XPCOMUtils.defineLazyModuleGetter(this, "BrowserUITelemetry",
-                                  "resource:///modules/BrowserUITelemetry.jsm");
-XPCOMUtils.defineLazyModuleGetter(this, "LightweightThemeManager",
-                                  "resource://gre/modules/LightweightThemeManager.jsm");
-XPCOMUtils.defineLazyModuleGetter(this, "SessionStore",
-                                  "resource:///modules/sessionstore/SessionStore.jsm");
-
-let gDebug;
-XPCOMUtils.defineLazyGetter(this, "log", () => {
-  let scope = {};
-  Cu.import("resource://gre/modules/Console.jsm", scope);
-  try {
-    gDebug = Services.prefs.getBoolPref(kPrefCustomizationDebug);
-  } catch (ex) {}
-  let consoleOptions = {
-    maxLogLevel: gDebug ? "all" : "log",
-    prefix: "CustomizeMode",
-  };
-  return new scope.ConsoleAPI(consoleOptions);
-});
-
-var gDisableAnimation = null;
-
-var gDraggingInToolbars;
-
-var gTab;
-
-function closeGlobalTab() {
-  let win = gTab.ownerGlobal;
-  if (win.gBrowser.browsers.length == 1) {
-    win.BrowserOpenTab();
-  }
-  win.gBrowser.removeTab(gTab);
-  gTab = null;
-}
-
-function unregisterGlobalTab() {
-  gTab.removeEventListener("TabClose", unregisterGlobalTab);
-  gTab.ownerGlobal.removeEventListener("unload", unregisterGlobalTab);
-  gTab.removeAttribute("customizemode");
-  gTab = null;
-}
-
-function CustomizeMode(aWindow) {
-  if (gDisableAnimation === null) {
-    gDisableAnimation = Services.prefs.getPrefType(kPrefCustomizationAnimation) == Ci.nsIPrefBranch.PREF_BOOL &&
-                        Services.prefs.getBoolPref(kPrefCustomizationAnimation);
-  }
-  this.window = aWindow;
-  this.document = aWindow.document;
-  this.browser = aWindow.gBrowser;
-  this.areas = new Set();
-
-  // There are two palettes - there's the palette that can be overlayed with
-  // toolbar items in browser.xul. This is invisible, and never seen by the
-  // user. Then there's the visible palette, which gets populated and displayed
-  // to the user when in customizing mode.
-  this.visiblePalette = this.document.getElementById(kPaletteId);
-  this.paletteEmptyNotice = this.document.getElementById("customization-empty");
-  if (Services.prefs.getCharPref("general.skins.selectedSkin") != "classic/1.0") {
-    let lwthemeButton = this.document.getElementById("customization-lwtheme-button");
-    lwthemeButton.setAttribute("hidden", "true");
-  }
-  if (AppConstants.CAN_DRAW_IN_TITLEBAR) {
-    this._updateTitlebarButton();
-    Services.prefs.addObserver(kDrawInTitlebarPref, this, false);
-  }
-  this.window.addEventListener("unload", this);
-}
-
-CustomizeMode.prototype = {
-  _changed: false,
-  _transitioning: false,
-  window: null,
-  document: null,
-  // areas is used to cache the customizable areas when in customization mode.
-  areas: null,
-  // When in customizing mode, we swap out the reference to the invisible
-  // palette in gNavToolbox.palette for our visiblePalette. This way, for the
-  // customizing browser window, when widgets are removed from customizable
-  // areas and added to the palette, they're added to the visible palette.
-  // _stowedPalette is a reference to the old invisible palette so we can
-  // restore gNavToolbox.palette to its original state after exiting
-  // customization mode.
-  _stowedPalette: null,
-  _dragOverItem: null,
-  _customizing: false,
-  _skipSourceNodeCheck: null,
-  _mainViewContext: null,
-
-  get panelUIContents() {
-    return this.document.getElementById("PanelUI-contents");
-  },
-
-  get _handler() {
-    return this.window.CustomizationHandler;
-  },
-
-  uninit: function() {
-    if (AppConstants.CAN_DRAW_IN_TITLEBAR) {
-      Services.prefs.removeObserver(kDrawInTitlebarPref, this);
-    }
-  },
-
-  toggle: function() {
-    if (this._handler.isEnteringCustomizeMode || this._handler.isExitingCustomizeMode) {
-      this._wantToBeInCustomizeMode = !this._wantToBeInCustomizeMode;
-      return;
-    }
-    if (this._customizing) {
-      this.exit();
-    } else {
-      this.enter();
-    }
-  },
-
-  _updateLWThemeButtonIcon: function() {
-    let lwthemeButton = this.document.getElementById("customization-lwtheme-button");
-    let lwthemeIcon = this.document.getAnonymousElementByAttribute(lwthemeButton,
-                        "class", "button-icon");
-    lwthemeIcon.style.backgroundImage = LightweightThemeManager.currentTheme ?
-      "url(" + LightweightThemeManager.currentTheme.iconURL + ")" : "";
-  },
-
-  setTab: function(aTab) {
-    if (gTab == aTab) {
-      return;
-    }
-
-    if (gTab) {
-      closeGlobalTab();
-    }
-
-    gTab = aTab;
-
-    gTab.setAttribute("customizemode", "true");
-    SessionStore.persistTabAttribute("customizemode");
-
-    gTab.linkedBrowser.stop();
-
-    let win = gTab.ownerGlobal;
-
-    win.gBrowser.setTabTitle(gTab);
-    win.gBrowser.setIcon(gTab,
-                         "chrome://browser/skin/customizableui/customizeFavicon.ico");
-
-    gTab.addEventListener("TabClose", unregisterGlobalTab);
-    win.addEventListener("unload", unregisterGlobalTab);
-
-    if (gTab.selected) {
-      win.gCustomizeMode.enter();
-    }
-  },
-
-  enter: function() {
-    this._wantToBeInCustomizeMode = true;
-
-    if (this._customizing || this._handler.isEnteringCustomizeMode) {
-      return;
-    }
-
-    // Exiting; want to re-enter once we've done that.
-    if (this._handler.isExitingCustomizeMode) {
-      log.debug("Attempted to enter while we're in the middle of exiting. " +
-                "We'll exit after we've entered");
-      return;
-    }
-
-    if (!gTab) {
-      this.setTab(this.browser.loadOneTab("about:blank",
-                                          { inBackground: false,
-                                            forceNotRemote: true,
-                                            skipAnimation: true }));
-      return;
-    }
-    if (!gTab.selected) {
-      // This will force another .enter() to be called via the
-      // onlocationchange handler of the tabbrowser, so we return early.
-      gTab.ownerGlobal.gBrowser.selectedTab = gTab;
-      return;
-    }
-    gTab.ownerGlobal.focus();
-    if (gTab.ownerDocument != this.document) {
-      return;
-    }
-
-    let window = this.window;
-    let document = this.document;
-
-    this._handler.isEnteringCustomizeMode = true;
-
-    // Always disable the reset button at the start of customize mode, it'll be re-enabled
-    // if necessary when we finish entering:
-    let resetButton = this.document.getElementById("customization-reset-button");
-    resetButton.setAttribute("disabled", "true");
-
-    Task.spawn(function*() {
-      // We shouldn't start customize mode until after browser-delayed-startup has finished:
-      if (!this.window.gBrowserInit.delayedStartupFinished) {
-        yield new Promise(resolve => {
-          let delayedStartupObserver = aSubject => {
-            if (aSubject == this.window) {
-              Services.obs.removeObserver(delayedStartupObserver, "browser-delayed-startup-finished");
-              resolve();
-            }
-          };
-
-          Services.obs.addObserver(delayedStartupObserver, "browser-delayed-startup-finished", false);
-        });
-      }
-
-      let toolbarVisibilityBtn = document.getElementById(kToolbarVisibilityBtn);
-      let togglableToolbars = window.getTogglableToolbars();
-      if (togglableToolbars.length == 0) {
-        toolbarVisibilityBtn.setAttribute("hidden", "true");
-      } else {
-        toolbarVisibilityBtn.removeAttribute("hidden");
-      }
-
-      this.updateLWTStyling();
-
-      CustomizableUI.dispatchToolboxEvent("beforecustomization", {}, window);
-      CustomizableUI.notifyStartCustomizing(this.window);
-
-      // Add a keypress listener to the document so that we can quickly exit
-      // customization mode when pressing ESC.
-      document.addEventListener("keypress", this);
-
-      // Same goes for the menu button - if we're customizing, a click on the
-      // menu button means a quick exit from customization mode.
-      window.PanelUI.hide();
-      window.PanelUI.menuButton.addEventListener("command", this);
-      window.PanelUI.menuButton.open = true;
-      window.PanelUI.beginBatchUpdate();
-
-      // The menu panel is lazy, and registers itself when the popup shows. We
-      // need to force the menu panel to register itself, or else customization
-      // is really not going to work. We pass "true" to ensureReady to
-      // indicate that we're handling calling startBatchUpdate and
-      // endBatchUpdate.
-      if (!window.PanelUI.isReady) {
-        yield window.PanelUI.ensureReady(true);
-      }
-
-      // Hide the palette before starting the transition for increased perf.
-      this.visiblePalette.hidden = true;
-      this.visiblePalette.removeAttribute("showing");
-
-      // Disable the button-text fade-out mask
-      // during the transition for increased perf.
-      let panelContents = window.PanelUI.contents;
-      panelContents.setAttribute("customize-transitioning", "true");
-
-      // Move the mainView in the panel to the holder so that we can see it
-      // while customizing.
-      let mainView = window.PanelUI.mainView;
-      let panelHolder = document.getElementById("customization-panelHolder");
-      panelHolder.appendChild(mainView);
-
-      let customizeButton = document.getElementById("PanelUI-customize");
-      customizeButton.setAttribute("enterLabel", customizeButton.getAttribute("label"));
-      customizeButton.setAttribute("label", customizeButton.getAttribute("exitLabel"));
-      customizeButton.setAttribute("enterTooltiptext", customizeButton.getAttribute("tooltiptext"));
-      customizeButton.setAttribute("tooltiptext", customizeButton.getAttribute("exitTooltiptext"));
-
-      this._transitioning = true;
-
-      let customizer = document.getElementById("customization-container");
-      customizer.parentNode.selectedPanel = customizer;
-      customizer.hidden = false;
-
-      this._wrapToolbarItemSync(CustomizableUI.AREA_TABSTRIP);
-
-      let customizableToolbars = document.querySelectorAll("toolbar[customizable=true]:not([autohide=true]):not([collapsed=true])");
-      for (let toolbar of customizableToolbars)
-        toolbar.setAttribute("customizing", true);
-
-      yield this._doTransition(true);
-
-      Services.obs.addObserver(this, "lightweight-theme-window-updated", false);
-
-      // Let everybody in this window know that we're about to customize.
-      CustomizableUI.dispatchToolboxEvent("customizationstarting", {}, window);
-
-      this._mainViewContext = mainView.getAttribute("context");
-      if (this._mainViewContext) {
-        mainView.removeAttribute("context");
-      }
-
-      this._showPanelCustomizationPlaceholders();
-
-      yield this._wrapToolbarItems();
-      this.populatePalette();
-
-      this._addDragHandlers(this.visiblePalette);
-
-      window.gNavToolbox.addEventListener("toolbarvisibilitychange", this);
-
-      document.getElementById("PanelUI-help").setAttribute("disabled", true);
-      document.getElementById("PanelUI-quit").setAttribute("disabled", true);
-
-      this._updateResetButton();
-      this._updateUndoResetButton();
-
-      this._skipSourceNodeCheck = Services.prefs.getPrefType(kSkipSourceNodePref) == Ci.nsIPrefBranch.PREF_BOOL &&
-                                  Services.prefs.getBoolPref(kSkipSourceNodePref);
-
-      CustomizableUI.addListener(this);
-      window.PanelUI.endBatchUpdate();
-      this._customizing = true;
-      this._transitioning = false;
-
-      // Show the palette now that the transition has finished.
-      this.visiblePalette.hidden = false;
-      window.setTimeout(() => {
-        // Force layout reflow to ensure the animation runs,
-        // and make it async so it doesn't affect the timing.
-        this.visiblePalette.clientTop;
-        this.visiblePalette.setAttribute("showing", "true");
-      }, 0);
-      this._updateEmptyPaletteNotice();
-
-      this._updateLWThemeButtonIcon();
-
-      this._handler.isEnteringCustomizeMode = false;
-      panelContents.removeAttribute("customize-transitioning");
-
-      CustomizableUI.dispatchToolboxEvent("customizationready", {}, window);
-      this._enableOutlinesTimeout = window.setTimeout(() => {
-        this.document.getElementById("nav-bar").setAttribute("showoutline", "true");
-        this.panelUIContents.setAttribute("showoutline", "true");
-        delete this._enableOutlinesTimeout;
-      }, 0);
-
-      if (!this._wantToBeInCustomizeMode) {
-        this.exit();
-      }
-    }.bind(this)).then(null, function(e) {
-      log.error("Error entering customize mode", e);
-      // We should ensure this has been called, and calling it again doesn't hurt:
-      window.PanelUI.endBatchUpdate();
-      this._handler.isEnteringCustomizeMode = false;
-      // Exit customize mode to ensure proper clean-up when entering failed.
-      this.exit();
-    }.bind(this));
-  },
-
-  exit: function() {
-    this._wantToBeInCustomizeMode = false;
-
-    if (!this._customizing || this._handler.isExitingCustomizeMode) {
-      return;
-    }
-
-    // Entering; want to exit once we've done that.
-    if (this._handler.isEnteringCustomizeMode) {
-      log.debug("Attempted to exit while we're in the middle of entering. " +
-                "We'll exit after we've entered");
-      return;
-    }
-
-    if (this.resetting) {
-      log.debug("Attempted to exit while we're resetting. " +
-                "We'll exit after resetting has finished.");
-      return;
-    }
-
-    this._handler.isExitingCustomizeMode = true;
-
-    if (this._enableOutlinesTimeout) {
-      this.window.clearTimeout(this._enableOutlinesTimeout);
-    } else {
-      this.document.getElementById("nav-bar").removeAttribute("showoutline");
-      this.panelUIContents.removeAttribute("showoutline");
-    }
-
-    this._removeExtraToolbarsIfEmpty();
-
-    CustomizableUI.removeListener(this);
-
-    this.document.removeEventListener("keypress", this);
-    this.window.PanelUI.menuButton.removeEventListener("command", this);
-    this.window.PanelUI.menuButton.open = false;
-
-    this.window.PanelUI.beginBatchUpdate();
-
-    this._removePanelCustomizationPlaceholders();
-
-    let window = this.window;
-    let document = this.document;
-
-    // Hide the palette before starting the transition for increased perf.
-    this.visiblePalette.hidden = true;
-    this.visiblePalette.removeAttribute("showing");
-    this.paletteEmptyNotice.hidden = true;
-
-    // Disable the button-text fade-out mask
-    // during the transition for increased perf.
-    let panelContents = window.PanelUI.contents;
-    panelContents.setAttribute("customize-transitioning", "true");
-
-    // Disable the reset and undo reset buttons while transitioning:
-    let resetButton = this.document.getElementById("customization-reset-button");
-    let undoResetButton = this.document.getElementById("customization-undo-reset-button");
-    undoResetButton.hidden = resetButton.disabled = true;
-
-    this._transitioning = true;
-
-    Task.spawn(function*() {
-      yield this.depopulatePalette();
-
-      yield this._doTransition(false);
-      this.removeLWTStyling();
-
-      Services.obs.removeObserver(this, "lightweight-theme-window-updated", false);
-
-      if (this.browser.selectedTab == gTab) {
-        if (gTab.linkedBrowser.currentURI.spec == "about:blank") {
-          closeGlobalTab();
-        } else {
-          unregisterGlobalTab();
-        }
-      }
-      let browser = document.getElementById("browser");
-      browser.parentNode.selectedPanel = browser;
-      let customizer = document.getElementById("customization-container");
-      customizer.hidden = true;
-
-      window.gNavToolbox.removeEventListener("toolbarvisibilitychange", this);
-
-      DragPositionManager.stop();
-      this._removeDragHandlers(this.visiblePalette);
-
-      yield this._unwrapToolbarItems();
-
-      if (this._changed) {
-        // XXXmconley: At first, it seems strange to also persist the old way with
-        //             currentset - but this might actually be useful for switching
-        //             to old builds. We might want to keep this around for a little
-        //             bit.
-        this.persistCurrentSets();
-      }
-
-      // And drop all area references.
-      this.areas.clear();
-
-      // Let everybody in this window know that we're starting to
-      // exit customization mode.
-      CustomizableUI.dispatchToolboxEvent("customizationending", {}, window);
-
-      window.PanelUI.setMainView(window.PanelUI.mainView);
-      window.PanelUI.menuButton.disabled = false;
-
-      let customizeButton = document.getElementById("PanelUI-customize");
-      customizeButton.setAttribute("exitLabel", customizeButton.getAttribute("label"));
-      customizeButton.setAttribute("label", customizeButton.getAttribute("enterLabel"));
-      customizeButton.setAttribute("exitTooltiptext", customizeButton.getAttribute("tooltiptext"));
-      customizeButton.setAttribute("tooltiptext", customizeButton.getAttribute("enterTooltiptext"));
-
-      // We have to use setAttribute/removeAttribute here instead of the
-      // property because the XBL property will be set later, and right
-      // now we'd be setting an expando, which breaks the XBL property.
-      document.getElementById("PanelUI-help").removeAttribute("disabled");
-      document.getElementById("PanelUI-quit").removeAttribute("disabled");
-
-      panelContents.removeAttribute("customize-transitioning");
-
-      // We need to set this._customizing to false before removing the tab
-      // or the TabSelect event handler will think that we are exiting
-      // customization mode for a second time.
-      this._customizing = false;
-
-      let mainView = window.PanelUI.mainView;
-      if (this._mainViewContext) {
-        mainView.setAttribute("context", this._mainViewContext);
-      }
-
-      let customizableToolbars = document.querySelectorAll("toolbar[customizable=true]:not([autohide=true])");
-      for (let toolbar of customizableToolbars)
-        toolbar.removeAttribute("customizing");
-
-      this.window.PanelUI.endBatchUpdate();
-      delete this._lastLightweightTheme;
-      this._changed = false;
-      this._transitioning = false;
-      this._handler.isExitingCustomizeMode = false;
-      CustomizableUI.dispatchToolboxEvent("aftercustomization", {}, window);
-      CustomizableUI.notifyEndCustomizing(window);
-
-      if (this._wantToBeInCustomizeMode) {
-        this.enter();
-      }
-    }.bind(this)).then(null, function(e) {
-      log.error("Error exiting customize mode", e);
-      // We should ensure this has been called, and calling it again doesn't hurt:
-      window.PanelUI.endBatchUpdate();
-      this._handler.isExitingCustomizeMode = false;
-    }.bind(this));
-  },
-
-  /**
-   * The customize mode transition has 4 phases when entering:
-   * 1) Pre-customization mode
-   *    This is the starting phase of the browser.
-   * 2) LWT swapping
-   *    This is where we swap some of the lightweight theme styles in order
-   *    to make them work in customize mode. We set/unset a customization-
-   *    lwtheme attribute iff we're using a lightweight theme.
-   * 3) customize-entering
-   *    This phase is a transition, optimized for smoothness.
-   * 4) customize-entered
-   *    After the transition completes, this phase draws all of the
-   *    expensive detail that isn't necessary during the second phase.
-   *
-   * Exiting customization mode has a similar set of phases, but in reverse
-   * order - customize-entered, customize-exiting, remove LWT swapping,
-   * pre-customization mode.
-   *
-   * When in the customize-entering, customize-entered, or customize-exiting
-   * phases, there is a "customizing" attribute set on the main-window to simplify
-   * excluding certain styles while in any phase of customize mode.
-   */
-  _doTransition: function(aEntering) {
-    let deck = this.document.getElementById("content-deck");
-    let customizeTransitionEndPromise = new Promise(resolve => {
-      let customizeTransitionEnd = (aEvent) => {
-        if (aEvent != "timedout" &&
-            (aEvent.originalTarget != deck || aEvent.propertyName != "margin-left")) {
-          return;
-        }
-        this.window.clearTimeout(catchAllTimeout);
-        // We request an animation frame to do the final stage of the transition
-        // to improve perceived performance. (bug 962677)
-        this.window.requestAnimationFrame(() => {
-          deck.removeEventListener("transitionend", customizeTransitionEnd);
-
-          if (!aEntering) {
-            this.document.documentElement.removeAttribute("customize-exiting");
-            this.document.documentElement.removeAttribute("customizing");
-          } else {
-            this.document.documentElement.setAttribute("customize-entered", true);
-            this.document.documentElement.removeAttribute("customize-entering");
-          }
-          CustomizableUI.dispatchToolboxEvent("customization-transitionend", aEntering, this.window);
-
-          resolve();
-        });
-      };
-      deck.addEventListener("transitionend", customizeTransitionEnd);
-      let catchAll = () => customizeTransitionEnd("timedout");
-      let catchAllTimeout = this.window.setTimeout(catchAll, kMaxTransitionDurationMs);
-    });
-
-    if (gDisableAnimation) {
-      this.document.getElementById("tab-view-deck").setAttribute("fastcustomizeanimation", true);
-    }
-
-    if (aEntering) {
-      this.document.documentElement.setAttribute("customizing", true);
-      this.document.documentElement.setAttribute("customize-entering", true);
-    } else {
-      this.document.documentElement.setAttribute("customize-exiting", true);
-      this.document.documentElement.removeAttribute("customize-entered");
-    }
-
-    return customizeTransitionEndPromise;
-  },
-
-  updateLWTStyling: function(aData) {
-    let docElement = this.document.documentElement;
-    if (!aData) {
-      let lwt = docElement._lightweightTheme;
-      aData = lwt.getData();
-    }
-    let headerURL = aData && aData.headerURL;
-    if (!headerURL) {
-      this.removeLWTStyling();
-      return;
-    }
-
-    let deck = this.document.getElementById("tab-view-deck");
-    let headerImageRef = this._getHeaderImageRef(aData);
-    docElement.setAttribute("customization-lwtheme", "true");
-
-    let toolboxRect = this.window.gNavToolbox.getBoundingClientRect();
-    let height = toolboxRect.bottom;
-
-    if (AppConstants.platform == "macosx") {
-      let drawingInTitlebar = !docElement.hasAttribute("drawtitle");
-      let titlebar = this.document.getElementById("titlebar");
-      if (drawingInTitlebar) {
-        titlebar.style.backgroundImage = headerImageRef;
-      } else {
-        titlebar.style.removeProperty("background-image");
-      }
-    }
-
-    let limitedBG = "-moz-image-rect(" + headerImageRef + ", 0, 100%, " +
-                    height + ", 0)";
-
-    let ridgeStart = height - 1;
-    let ridgeCenter = (ridgeStart + 1) + "px";
-    let ridgeEnd = (ridgeStart + 2) + "px";
-    ridgeStart = ridgeStart + "px";
-
-    let ridge = "linear-gradient(to bottom, " +
-                                 "transparent " + ridgeStart +
-                                 ", rgba(0,0,0,0.25) " + ridgeStart +
-                                 ", rgba(0,0,0,0.25) " + ridgeCenter +
-                                 ", rgba(255,255,255,0.5) " + ridgeCenter +
-                                 ", rgba(255,255,255,0.5) " + ridgeEnd + ", " +
-                                 "transparent " + ridgeEnd + ")";
-    deck.style.backgroundImage = ridge + ", " + limitedBG;
-
-    /* Remove the background styles from the <window> so we can style it instead. */
-    docElement.style.removeProperty("background-image");
-    docElement.style.removeProperty("background-color");
-  },
-
-  removeLWTStyling: function() {
-    let affectedNodes = AppConstants.platform == "macosx" ?
-                          ["tab-view-deck", "titlebar"] :
-                          ["tab-view-deck"];
-    for (let id of affectedNodes) {
-      let node = this.document.getElementById(id);
-      node.style.removeProperty("background-image");
-    }
-    let docElement = this.document.documentElement;
-    docElement.removeAttribute("customization-lwtheme");
-    let data = docElement._lightweightTheme.getData();
-    if (data && data.headerURL) {
-      docElement.style.backgroundImage = this._getHeaderImageRef(data);
-      docElement.style.backgroundColor = data.accentcolor || "white";
-    }
-  },
-
-  _getHeaderImageRef: function(aData) {
-    return "url(\"" + aData.headerURL.replace(/"/g, '\\"') + "\")";
-  },
-
-  _getCustomizableChildForNode: function(aNode) {
-    // NB: adjusted from _getCustomizableParent to keep that method fast
-    // (it's used during drags), and avoid multiple DOM loops
-    let areas = CustomizableUI.areas;
-    // Caching this length is important because otherwise we'll also iterate
-    // over items we add to the end from within the loop.
-    let numberOfAreas = areas.length;
-    for (let i = 0; i < numberOfAreas; i++) {
-      let area = areas[i];
-      let areaNode = aNode.ownerDocument.getElementById(area);
-      let customizationTarget = areaNode && areaNode.customizationTarget;
-      if (customizationTarget && customizationTarget != areaNode) {
-        areas.push(customizationTarget.id);
-      }
-      let overflowTarget = areaNode && areaNode.getAttribute("overflowtarget");
-      if (overflowTarget) {
-        areas.push(overflowTarget);
-      }
-    }
-    areas.push(kPaletteId);
-
-    while (aNode && aNode.parentNode) {
-      let parent = aNode.parentNode;
-      if (areas.indexOf(parent.id) != -1) {
-        return aNode;
-      }
-      aNode = parent;
-    }
-    return null;
-  },
-
-  addToToolbar: function(aNode) {
-    aNode = this._getCustomizableChildForNode(aNode);
-    if (aNode.localName == "toolbarpaletteitem" && aNode.firstChild) {
-      aNode = aNode.firstChild;
-    }
-    CustomizableUI.addWidgetToArea(aNode.id, CustomizableUI.AREA_NAVBAR);
-    if (!this._customizing) {
-      CustomizableUI.dispatchToolboxEvent("customizationchange");
-    }
-  },
-
-  addToPanel: function(aNode) {
-    aNode = this._getCustomizableChildForNode(aNode);
-    if (aNode.localName == "toolbarpaletteitem" && aNode.firstChild) {
-      aNode = aNode.firstChild;
-    }
-    CustomizableUI.addWidgetToArea(aNode.id, CustomizableUI.AREA_PANEL);
-    if (!this._customizing) {
-      CustomizableUI.dispatchToolboxEvent("customizationchange");
-    }
-  },
-
-  removeFromArea: function(aNode) {
-    aNode = this._getCustomizableChildForNode(aNode);
-    if (aNode.localName == "toolbarpaletteitem" && aNode.firstChild) {
-      aNode = aNode.firstChild;
-    }
-    CustomizableUI.removeWidgetFromArea(aNode.id);
-    if (!this._customizing) {
-      CustomizableUI.dispatchToolboxEvent("customizationchange");
-    }
-  },
-
-  populatePalette: function() {
-    let fragment = this.document.createDocumentFragment();
-    let toolboxPalette = this.window.gNavToolbox.palette;
-
-    try {
-      let unusedWidgets = CustomizableUI.getUnusedWidgets(toolboxPalette);
-      for (let widget of unusedWidgets) {
-        let paletteItem = this.makePaletteItem(widget, "palette");
-        if (!paletteItem) {
-          continue;
-        }
-        fragment.appendChild(paletteItem);
-      }
-
-      this.visiblePalette.appendChild(fragment);
-      this._stowedPalette = this.window.gNavToolbox.palette;
-      this.window.gNavToolbox.palette = this.visiblePalette;
-    } catch (ex) {
-      log.error(ex);
-    }
-  },
-
-  // XXXunf Maybe this should use -moz-element instead of wrapping the node?
-  //       Would ensure no weird interactions/event handling from original node,
-  //       and makes it possible to put this in a lazy-loaded iframe/real tab
-  //       while still getting rid of the need for overlays.
-  makePaletteItem: function(aWidget, aPlace) {
-    let widgetNode = aWidget.forWindow(this.window).node;
-    if (!widgetNode) {
-      log.error("Widget with id " + aWidget.id + " does not return a valid node");
-      return null;
-    }
-    // Do not build a palette item for hidden widgets; there's not much to show.
-    if (widgetNode.hidden) {
-      return null;
-    }
-
-    let wrapper = this.createOrUpdateWrapper(widgetNode, aPlace);
-    wrapper.appendChild(widgetNode);
-    return wrapper;
-  },
-
-  depopulatePalette: function() {
-    return Task.spawn(function*() {
-      this.visiblePalette.hidden = true;
-      let paletteChild = this.visiblePalette.firstChild;
-      let nextChild;
-      while (paletteChild) {
-        nextChild = paletteChild.nextElementSibling;
-        let provider = CustomizableUI.getWidget(paletteChild.id).provider;
-        if (provider == CustomizableUI.PROVIDER_XUL) {
-          let unwrappedPaletteItem =
-            yield this.deferredUnwrapToolbarItem(paletteChild);
-          this._stowedPalette.appendChild(unwrappedPaletteItem);
-        } else if (provider == CustomizableUI.PROVIDER_API) {
-          // XXXunf Currently this doesn't destroy the (now unused) node. It would
-          //       be good to do so, but we need to keep strong refs to it in
-          //       CustomizableUI (can't iterate of WeakMaps), and there's the
-          //       question of what behavior wrappers should have if consumers
-          //       keep hold of them.
-          // widget.destroyInstance(widgetNode);
-        } else if (provider == CustomizableUI.PROVIDER_SPECIAL) {
-          this.visiblePalette.removeChild(paletteChild);
-        }
-
-        paletteChild = nextChild;
-      }
-      this.visiblePalette.hidden = false;
-      this.window.gNavToolbox.palette = this._stowedPalette;
-    }.bind(this)).then(null, log.error);
-  },
-
-  isCustomizableItem: function(aNode) {
-    return aNode.localName == "toolbarbutton" ||
-           aNode.localName == "toolbaritem" ||
-           aNode.localName == "toolbarseparator" ||
-           aNode.localName == "toolbarspring" ||
-           aNode.localName == "toolbarspacer";
-  },
-
-  isWrappedToolbarItem: function(aNode) {
-    return aNode.localName == "toolbarpaletteitem";
-  },
-
-  deferredWrapToolbarItem: function(aNode, aPlace) {
-    return new Promise(resolve => {
-      dispatchFunction(() => {
-        let wrapper = this.wrapToolbarItem(aNode, aPlace);
-        resolve(wrapper);
-      });
-    });
-  },
-
-  wrapToolbarItem: function(aNode, aPlace) {
-    if (!this.isCustomizableItem(aNode)) {
-      return aNode;
-    }
-    let wrapper = this.createOrUpdateWrapper(aNode, aPlace);
-
-    // It's possible that this toolbar node is "mid-flight" and doesn't have
-    // a parent, in which case we skip replacing it. This can happen if a
-    // toolbar item has been dragged into the palette. In that case, we tell
-    // CustomizableUI to remove the widget from its area before putting the
-    // widget in the palette - so the node will have no parent.
-    if (aNode.parentNode) {
-      aNode = aNode.parentNode.replaceChild(wrapper, aNode);
-    }
-    wrapper.appendChild(aNode);
-    return wrapper;
-  },
-
-  createOrUpdateWrapper: function(aNode, aPlace, aIsUpdate) {
-    let wrapper;
-    if (aIsUpdate && aNode.parentNode && aNode.parentNode.localName == "toolbarpaletteitem") {
-      wrapper = aNode.parentNode;
-      aPlace = wrapper.getAttribute("place");
-    } else {
-      wrapper = this.document.createElement("toolbarpaletteitem");
-      // "place" is used by toolkit to add the toolbarpaletteitem-palette
-      // binding to a toolbarpaletteitem, which gives it a label node for when
-      // it's sitting in the palette.
-      wrapper.setAttribute("place", aPlace);
-    }
-
-
-    // Ensure the wrapped item doesn't look like it's in any special state, and
-    // can't be interactved with when in the customization palette.
-    if (aNode.hasAttribute("command")) {
-      wrapper.setAttribute("itemcommand", aNode.getAttribute("command"));
-      aNode.removeAttribute("command");
-    }
-
-    if (aNode.hasAttribute("observes")) {
-      wrapper.setAttribute("itemobserves", aNode.getAttribute("observes"));
-      aNode.removeAttribute("observes");
-    }
-
-    if (aNode.getAttribute("checked") == "true") {
-      wrapper.setAttribute("itemchecked", "true");
-      aNode.removeAttribute("checked");
-    }
-
-    if (aNode.hasAttribute("id")) {
-      wrapper.setAttribute("id", "wrapper-" + aNode.getAttribute("id"));
-    }
-
-    if (aNode.hasAttribute("label")) {
-      wrapper.setAttribute("title", aNode.getAttribute("label"));
-      wrapper.setAttribute("tooltiptext", aNode.getAttribute("label"));
-    } else if (aNode.hasAttribute("title")) {
-      wrapper.setAttribute("title", aNode.getAttribute("title"));
-      wrapper.setAttribute("tooltiptext", aNode.getAttribute("title"));
-    }
-
-    if (aNode.hasAttribute("flex")) {
-      wrapper.setAttribute("flex", aNode.getAttribute("flex"));
-    }
-
-    if (aPlace == "panel") {
-      if (aNode.classList.contains(CustomizableUI.WIDE_PANEL_CLASS)) {
-        wrapper.setAttribute("haswideitem", "true");
-      } else if (wrapper.hasAttribute("haswideitem")) {
-        wrapper.removeAttribute("haswideitem");
-      }
-    }
-
-    let removable = aPlace == "palette" || CustomizableUI.isWidgetRemovable(aNode);
-    wrapper.setAttribute("removable", removable);
-
-    let contextMenuAttrName = "";
-    if (aNode.getAttribute("context")) {
-      contextMenuAttrName = "context";
-    } else if (aNode.getAttribute("contextmenu")) {
-      contextMenuAttrName = "contextmenu";
-    }
-    let currentContextMenu = aNode.getAttribute(contextMenuAttrName);
-    let contextMenuForPlace = aPlace == "panel" ?
-                                kPanelItemContextMenu :
-                                kPaletteItemContextMenu;
-    if (aPlace != "toolbar") {
-      wrapper.setAttribute("context", contextMenuForPlace);
-    }
-    // Only keep track of the menu if it is non-default.
-    if (currentContextMenu &&
-        currentContextMenu != contextMenuForPlace) {
-      aNode.setAttribute("wrapped-context", currentContextMenu);
-      aNode.setAttribute("wrapped-contextAttrName", contextMenuAttrName)
-      aNode.removeAttribute(contextMenuAttrName);
-    } else if (currentContextMenu == contextMenuForPlace) {
-      aNode.removeAttribute(contextMenuAttrName);
-    }
-
-    // Only add listeners for newly created wrappers:
-    if (!aIsUpdate) {
-      wrapper.addEventListener("mousedown", this);
-      wrapper.addEventListener("mouseup", this);
-    }
-
-    return wrapper;
-  },
-
-  deferredUnwrapToolbarItem: function(aWrapper) {
-    return new Promise(resolve => {
-      dispatchFunction(() => {
-        let item = null;
-        try {
-          item = this.unwrapToolbarItem(aWrapper);
-        } catch (ex) {
-          Cu.reportError(ex);
-        }
-        resolve(item);
-      });
-    });
-  },
-
-  unwrapToolbarItem: function(aWrapper) {
-    if (aWrapper.nodeName != "toolbarpaletteitem") {
-      return aWrapper;
-    }
-    aWrapper.removeEventListener("mousedown", this);
-    aWrapper.removeEventListener("mouseup", this);
-
-    let place = aWrapper.getAttribute("place");
-
-    let toolbarItem = aWrapper.firstChild;
-    if (!toolbarItem) {
-      log.error("no toolbarItem child for " + aWrapper.tagName + "#" + aWrapper.id);
-      aWrapper.remove();
-      return null;
-    }
-
-    if (aWrapper.hasAttribute("itemobserves")) {
-      toolbarItem.setAttribute("observes", aWrapper.getAttribute("itemobserves"));
-    }
-
-    if (aWrapper.hasAttribute("itemchecked")) {
-      toolbarItem.checked = true;
-    }
-
-    if (aWrapper.hasAttribute("itemcommand")) {
-      let commandID = aWrapper.getAttribute("itemcommand");
-      toolbarItem.setAttribute("command", commandID);
-
-      // XXX Bug 309953 - toolbarbuttons aren't in sync with their commands after customizing
-      let command = this.document.getElementById(commandID);
-      if (command && command.hasAttribute("disabled")) {
-        toolbarItem.setAttribute("disabled", command.getAttribute("disabled"));
-      }
-    }
-
-    let wrappedContext = toolbarItem.getAttribute("wrapped-context");
-    if (wrappedContext) {
-      let contextAttrName = toolbarItem.getAttribute("wrapped-contextAttrName");
-      toolbarItem.setAttribute(contextAttrName, wrappedContext);
-      toolbarItem.removeAttribute("wrapped-contextAttrName");
-      toolbarItem.removeAttribute("wrapped-context");
-    } else if (place == "panel") {
-      toolbarItem.setAttribute("context", kPanelItemContextMenu);
-    }
-
-    if (aWrapper.parentNode) {
-      aWrapper.parentNode.replaceChild(toolbarItem, aWrapper);
-    }
-    return toolbarItem;
-  },
-
-  _wrapToolbarItem: function*(aArea) {
-    let target = CustomizableUI.getCustomizeTargetForArea(aArea, this.window);
-    if (!target || this.areas.has(target)) {
-      return null;
-    }
-
-    this._addDragHandlers(target);
-    for (let child of target.children) {
-      if (this.isCustomizableItem(child) && !this.isWrappedToolbarItem(child)) {
-        yield this.deferredWrapToolbarItem(child, CustomizableUI.getPlaceForItem(child)).then(null, log.error);
-      }
-    }
-    this.areas.add(target);
-    return target;
-  },
-
-  _wrapToolbarItemSync: function(aArea) {
-    let target = CustomizableUI.getCustomizeTargetForArea(aArea, this.window);
-    if (!target || this.areas.has(target)) {
-      return null;
-    }
-
-    this._addDragHandlers(target);
-    try {
-      for (let child of target.children) {
-        if (this.isCustomizableItem(child) && !this.isWrappedToolbarItem(child)) {
-          this.wrapToolbarItem(child, CustomizableUI.getPlaceForItem(child));
-        }
-      }
-    } catch (ex) {
-      log.error(ex, ex.stack);
-    }
-
-    this.areas.add(target);
-    return target;
-  },
-
-  _wrapToolbarItems: function*() {
-    for (let area of CustomizableUI.areas) {
-      yield this._wrapToolbarItem(area);
-    }
-  },
-
-  _addDragHandlers: function(aTarget) {
-    aTarget.addEventListener("dragstart", this, true);
-    aTarget.addEventListener("dragover", this, true);
-    aTarget.addEventListener("dragexit", this, true);
-    aTarget.addEventListener("drop", this, true);
-    aTarget.addEventListener("dragend", this, true);
-  },
-
-  _wrapItemsInArea: function(target) {
-    for (let child of target.children) {
-      if (this.isCustomizableItem(child)) {
-        this.wrapToolbarItem(child, CustomizableUI.getPlaceForItem(child));
-      }
-    }
-  },
-
-  _removeDragHandlers: function(aTarget) {
-    aTarget.removeEventListener("dragstart", this, true);
-    aTarget.removeEventListener("dragover", this, true);
-    aTarget.removeEventListener("dragexit", this, true);
-    aTarget.removeEventListener("drop", this, true);
-    aTarget.removeEventListener("dragend", this, true);
-  },
-
-  _unwrapItemsInArea: function(target) {
-    for (let toolbarItem of target.children) {
-      if (this.isWrappedToolbarItem(toolbarItem)) {
-        this.unwrapToolbarItem(toolbarItem);
-      }
-    }
-  },
-
-  _unwrapToolbarItems: function() {
-    return Task.spawn(function*() {
-      for (let target of this.areas) {
-        for (let toolbarItem of target.children) {
-          if (this.isWrappedToolbarItem(toolbarItem)) {
-            yield this.deferredUnwrapToolbarItem(toolbarItem);
-          }
-        }
-        this._removeDragHandlers(target);
-      }
-      this.areas.clear();
-    }.bind(this)).then(null, log.error);
-  },
-
-  _removeExtraToolbarsIfEmpty: function() {
-    let toolbox = this.window.gNavToolbox;
-    for (let child of toolbox.children) {
-      if (child.hasAttribute("customindex")) {
-        let placements = CustomizableUI.getWidgetIdsInArea(child.id);
-        if (!placements.length) {
-          CustomizableUI.removeExtraToolbar(child.id);
-        }
-      }
-    }
-  },
-
-  persistCurrentSets: function(aSetBeforePersisting)  {
-    let document = this.document;
-    let toolbars = document.querySelectorAll("toolbar[customizable='true'][currentset]");
-    for (let toolbar of toolbars) {
-      if (aSetBeforePersisting) {
-        let set = toolbar.currentSet;
-        toolbar.setAttribute("currentset", set);
-      }
-      // Persist the currentset attribute directly on hardcoded toolbars.
-      document.persist(toolbar.id, "currentset");
-    }
-  },
-
-  reset: function() {
-    this.resetting = true;
-    // Disable the reset button temporarily while resetting:
-    let btn = this.document.getElementById("customization-reset-button");
-    BrowserUITelemetry.countCustomizationEvent("reset");
-    btn.disabled = true;
-    return Task.spawn(function*() {
-      this._removePanelCustomizationPlaceholders();
-      yield this.depopulatePalette();
-      yield this._unwrapToolbarItems();
-
-      CustomizableUI.reset();
-
-      this._updateLWThemeButtonIcon();
-
-      yield this._wrapToolbarItems();
-      this.populatePalette();
-
-      this.persistCurrentSets(true);
-
-      this._updateResetButton();
-      this._updateUndoResetButton();
-      this._updateEmptyPaletteNotice();
-      this._showPanelCustomizationPlaceholders();
-      this.resetting = false;
-      if (!this._wantToBeInCustomizeMode) {
-        this.exit();
-      }
-    }.bind(this)).then(null, log.error);
-  },
-
-  undoReset: function() {
-    this.resetting = true;
-
-    return Task.spawn(function*() {
-      this._removePanelCustomizationPlaceholders();
-      yield this.depopulatePalette();
-      yield this._unwrapToolbarItems();
-
-      CustomizableUI.undoReset();
-
-      this._updateLWThemeButtonIcon();
-
-      yield this._wrapToolbarItems();
-      this.populatePalette();
-
-      this.persistCurrentSets(true);
-
-      this._updateResetButton();
-      this._updateUndoResetButton();
-      this._updateEmptyPaletteNotice();
-      this.resetting = false;
-    }.bind(this)).then(null, log.error);
-  },
-
-  _onToolbarVisibilityChange: function(aEvent) {
-    let toolbar = aEvent.target;
-    if (aEvent.detail.visible && toolbar.getAttribute("customizable") == "true") {
-      toolbar.setAttribute("customizing", "true");
-    } else {
-      toolbar.removeAttribute("customizing");
-    }
-    this._onUIChange();
-    this.updateLWTStyling();
-  },
-
-  onWidgetMoved: function(aWidgetId, aArea, aOldPosition, aNewPosition) {
-    this._onUIChange();
-  },
-
-  onWidgetAdded: function(aWidgetId, aArea, aPosition) {
-    this._onUIChange();
-  },
-
-  onWidgetRemoved: function(aWidgetId, aArea) {
-    this._onUIChange();
-  },
-
-  onWidgetBeforeDOMChange: function(aNodeToChange, aSecondaryNode, aContainer) {
-    if (aContainer.ownerGlobal != this.window || this.resetting) {
-      return;
-    }
-    if (aContainer.id == CustomizableUI.AREA_PANEL) {
-      this._removePanelCustomizationPlaceholders();
-    }
-    // If we get called for widgets that aren't in the window yet, they might not have
-    // a parentNode at all.
-    if (aNodeToChange.parentNode) {
-      this.unwrapToolbarItem(aNodeToChange.parentNode);
-    }
-    if (aSecondaryNode) {
-      this.unwrapToolbarItem(aSecondaryNode.parentNode);
-    }
-  },
-
-  onWidgetAfterDOMChange: function(aNodeToChange, aSecondaryNode, aContainer) {
-    if (aContainer.ownerGlobal != this.window || this.resetting) {
-      return;
-    }
-    // If the node is still attached to the container, wrap it again:
-    if (aNodeToChange.parentNode) {
-      let place = CustomizableUI.getPlaceForItem(aNodeToChange);
-      this.wrapToolbarItem(aNodeToChange, place);
-      if (aSecondaryNode) {
-        this.wrapToolbarItem(aSecondaryNode, place);
-      }
-    } else {
-      // If not, it got removed.
-
-      // If an API-based widget is removed while customizing, append it to the palette.
-      // The _applyDrop code itself will take care of positioning it correctly, if
-      // applicable. We need the code to be here so removing widgets using CustomizableUI's
-      // API also does the right thing (and adds it to the palette)
-      let widgetId = aNodeToChange.id;
-      let widget = CustomizableUI.getWidget(widgetId);
-      if (widget.provider == CustomizableUI.PROVIDER_API) {
-        let paletteItem = this.makePaletteItem(widget, "palette");
-        this.visiblePalette.appendChild(paletteItem);
-      }
-    }
-    if (aContainer.id == CustomizableUI.AREA_PANEL) {
-      this._showPanelCustomizationPlaceholders();
-    }
-  },
-
-  onWidgetDestroyed: function(aWidgetId) {
-    let wrapper = this.document.getElementById("wrapper-" + aWidgetId);
-    if (wrapper) {
-      let wasInPanel = wrapper.parentNode == this.panelUIContents;
-      wrapper.remove();
-      if (wasInPanel) {
-        this._showPanelCustomizationPlaceholders();
-      }
-    }
-  },
-
-  onWidgetAfterCreation: function(aWidgetId, aArea) {
-    // If the node was added to an area, we would have gotten an onWidgetAdded notification,
-    // plus associated DOM change notifications, so only do stuff for the palette:
-    if (!aArea) {
-      let widgetNode = this.document.getElementById(aWidgetId);
-      if (widgetNode) {
-        this.wrapToolbarItem(widgetNode, "palette");
-      } else {
-        let widget = CustomizableUI.getWidget(aWidgetId);
-        this.visiblePalette.appendChild(this.makePaletteItem(widget, "palette"));
-      }
-    }
-  },
-
-  onAreaNodeRegistered: function(aArea, aContainer) {
-    if (aContainer.ownerDocument == this.document) {
-      this._wrapItemsInArea(aContainer);
-      this._addDragHandlers(aContainer);
-      DragPositionManager.add(this.window, aArea, aContainer);
-      this.areas.add(aContainer);
-    }
-  },
-
-  onAreaNodeUnregistered: function(aArea, aContainer, aReason) {
-    if (aContainer.ownerDocument == this.document && aReason == CustomizableUI.REASON_AREA_UNREGISTERED) {
-      this._unwrapItemsInArea(aContainer);
-      this._removeDragHandlers(aContainer);
-      DragPositionManager.remove(this.window, aArea, aContainer);
-      this.areas.delete(aContainer);
-    }
-  },
-
-  openAddonsManagerThemes: function(aEvent) {
-    aEvent.target.parentNode.parentNode.hidePopup();
-    this.window.BrowserOpenAddonsMgr('addons://list/theme');
-  },
-
-  getMoreThemes: function(aEvent) {
-    aEvent.target.parentNode.parentNode.hidePopup();
-    let getMoreURL = Services.urlFormatter.formatURLPref("lightweightThemes.getMoreURL");
-    this.window.openUILinkIn(getMoreURL, "tab");
-  },
-
-  onLWThemesMenuShowing: function(aEvent) {
-    const DEFAULT_THEME_ID = "{972ce4c6-7e08-4474-a285-3208198ce6fd}";
-    const RECENT_LWT_COUNT = 5;
-
-    this._clearLWThemesMenu(aEvent.target);
-
-    function previewTheme(aEvent) {
-      LightweightThemeManager.previewTheme(aEvent.target.theme.id != DEFAULT_THEME_ID ?
-                                           aEvent.target.theme : null);
-    }
-
-    function resetPreview() {
-      LightweightThemeManager.resetPreview();
-    }
-
-    let onThemeSelected = panel => {
-      this._updateLWThemeButtonIcon();
-      this._onUIChange();
-      panel.hidePopup();
-    };
-
-    AddonManager.getAddonByID(DEFAULT_THEME_ID, function(aDefaultTheme) {
-      let doc = this.window.document;
-
-      function buildToolbarButton(aTheme) {
-        let tbb = doc.createElement("toolbarbutton");
-        tbb.theme = aTheme;
-        tbb.setAttribute("label", aTheme.name);
-        if (aDefaultTheme == aTheme) {
-          // The actual icon is set up so it looks nice in about:addons, but
-          // we'd like the version that's correct for the OS we're on, so we set
-          // an attribute that our styling will then use to display the icon.
-          tbb.setAttribute("defaulttheme", "true");
-        } else {
-          tbb.setAttribute("image", aTheme.iconURL);
-        }
-        if (aTheme.description)
-          tbb.setAttribute("tooltiptext", aTheme.description);
-        tbb.setAttribute("tabindex", "0");
-        tbb.classList.add("customization-lwtheme-menu-theme");
-        tbb.setAttribute("aria-checked", aTheme.isActive);
-        tbb.setAttribute("role", "menuitemradio");
-        if (aTheme.isActive) {
-          tbb.setAttribute("active", "true");
-        }
-        tbb.addEventListener("focus", previewTheme);
-        tbb.addEventListener("mouseover", previewTheme);
-        tbb.addEventListener("blur", resetPreview);
-        tbb.addEventListener("mouseout", resetPreview);
-
-        return tbb;
-      }
-
-      let themes = [aDefaultTheme];
-      let lwts = LightweightThemeManager.usedThemes;
-      if (lwts.length > RECENT_LWT_COUNT)
-        lwts.length = RECENT_LWT_COUNT;
-      let currentLwt = LightweightThemeManager.currentTheme;
-      for (let lwt of lwts) {
-        lwt.isActive = !!currentLwt && (lwt.id == currentLwt.id);
-        themes.push(lwt);
-      }
-
-      let footer = doc.getElementById("customization-lwtheme-menu-footer");
-      let panel = footer.parentNode;
-      let recommendedLabel = doc.getElementById("customization-lwtheme-menu-recommended");
-      for (let theme of themes) {
-        let button = buildToolbarButton(theme);
-        button.addEventListener("command", () => {
-          if ("userDisabled" in button.theme)
-            button.theme.userDisabled = false;
-          else
-            LightweightThemeManager.currentTheme = button.theme;
-          onThemeSelected(panel);
-        });
-        panel.insertBefore(button, recommendedLabel);
-      }
-
-      let lwthemePrefs = Services.prefs.getBranch("lightweightThemes.");
-      let recommendedThemes = lwthemePrefs.getComplexValue("recommendedThemes",
-                                                           Ci.nsISupportsString).data;
-      recommendedThemes = JSON.parse(recommendedThemes);
-      let sb = Services.strings.createBundle("chrome://browser/locale/lightweightThemes.properties");
-      for (let theme of recommendedThemes) {
-        theme.name = sb.GetStringFromName("lightweightThemes." + theme.id + ".name");
-        theme.description = sb.GetStringFromName("lightweightThemes." + theme.id + ".description");
-        let button = buildToolbarButton(theme);
-        button.addEventListener("command", () => {
-          LightweightThemeManager.setLocalTheme(button.theme);
-          recommendedThemes = recommendedThemes.filter((aTheme) => { return aTheme.id != button.theme.id; });
-          let string = Cc["@mozilla.org/supports-string;1"]
-                         .createInstance(Ci.nsISupportsString);
-          string.data = JSON.stringify(recommendedThemes);
-          lwthemePrefs.setComplexValue("recommendedThemes",
-                                       Ci.nsISupportsString, string);
-          onThemeSelected(panel);
-        });
-        panel.insertBefore(button, footer);
-      }
-      let hideRecommendedLabel = (footer.previousSibling == recommendedLabel);
-      recommendedLabel.hidden = hideRecommendedLabel;
-    }.bind(this));
-  },
-
-  _clearLWThemesMenu: function(panel) {
-    let footer = this.document.getElementById("customization-lwtheme-menu-footer");
-    let recommendedLabel = this.document.getElementById("customization-lwtheme-menu-recommended");
-    for (let element of [footer, recommendedLabel]) {
-      while (element.previousSibling &&
-             element.previousSibling.localName == "toolbarbutton") {
-        element.previousSibling.remove();
-      }
-    }
-
-    // Workaround for bug 1059934
-    panel.removeAttribute("height");
-  },
-
-  _onUIChange: function() {
-    this._changed = true;
-    if (!this.resetting) {
-      this._updateResetButton();
-      this._updateUndoResetButton();
-      this._updateEmptyPaletteNotice();
-    }
-    CustomizableUI.dispatchToolboxEvent("customizationchange");
-  },
-
-  _updateEmptyPaletteNotice: function() {
-    let paletteItems = this.visiblePalette.getElementsByTagName("toolbarpaletteitem");
-    this.paletteEmptyNotice.hidden = !!paletteItems.length;
-  },
-
-  _updateResetButton: function() {
-    let btn = this.document.getElementById("customization-reset-button");
-    btn.disabled = CustomizableUI.inDefaultState;
-  },
-
-  _updateUndoResetButton: function() {
-    let undoResetButton =  this.document.getElementById("customization-undo-reset-button");
-    undoResetButton.hidden = !CustomizableUI.canUndoReset;
-  },
-
-  handleEvent: function(aEvent) {
-    switch (aEvent.type) {
-      case "toolbarvisibilitychange":
-        this._onToolbarVisibilityChange(aEvent);
-        break;
-      case "dragstart":
-        this._onDragStart(aEvent);
-        break;
-      case "dragover":
-        this._onDragOver(aEvent);
-        break;
-      case "drop":
-        this._onDragDrop(aEvent);
-        break;
-      case "dragexit":
-        this._onDragExit(aEvent);
-        break;
-      case "dragend":
-        this._onDragEnd(aEvent);
-        break;
-      case "command":
-        if (aEvent.originalTarget == this.window.PanelUI.menuButton) {
-          this.exit();
-          aEvent.preventDefault();
-        }
-        break;
-      case "mousedown":
-        this._onMouseDown(aEvent);
-        break;
-      case "mouseup":
-        this._onMouseUp(aEvent);
-        break;
-      case "keypress":
-        if (aEvent.keyCode == aEvent.DOM_VK_ESCAPE) {
-          this.exit();
-        }
-        break;
-      case "unload":
-        this.uninit();
-        break;
-    }
-  },
-
-  observe: function(aSubject, aTopic, aData) {
-    switch (aTopic) {
-      case "nsPref:changed":
-        this._updateResetButton();
-        this._updateUndoResetButton();
-        if (AppConstants.CAN_DRAW_IN_TITLEBAR) {
-          this._updateTitlebarButton();
-        }
-        break;
-      case "lightweight-theme-window-updated":
-        if (aSubject == this.window) {
-          aData = JSON.parse(aData);
-          if (!aData) {
-            this.removeLWTStyling();
-          } else {
-            this.updateLWTStyling(aData);
-          }
-        }
-        break;
-    }
-  },
-
-  _updateTitlebarButton: function() {
-    if (!AppConstants.CAN_DRAW_IN_TITLEBAR) {
-      return;
-    }
-    let drawInTitlebar = true;
-    try {
-      drawInTitlebar = Services.prefs.getBoolPref(kDrawInTitlebarPref);
-    } catch (ex) { }
-    let button = this.document.getElementById("customization-titlebar-visibility-button");
-    // Drawing in the titlebar means 'hiding' the titlebar:
-    if (drawInTitlebar) {
-      button.removeAttribute("checked");
-    } else {
-      button.setAttribute("checked", "true");
-    }
-  },
-
-  toggleTitlebar: function(aShouldShowTitlebar) {
-    if (!AppConstants.CAN_DRAW_IN_TITLEBAR) {
-      return;
-    }
-    // Drawing in the titlebar means not showing the titlebar, hence the negation:
-    Services.prefs.setBoolPref(kDrawInTitlebarPref, !aShouldShowTitlebar);
-  },
-
-  _onDragStart: function(aEvent) {
-    __dumpDragData(aEvent);
-    let item = aEvent.target;
-    while (item && item.localName != "toolbarpaletteitem") {
-      if (item.localName == "toolbar") {
-        return;
-      }
-      item = item.parentNode;
-    }
-
-    let draggedItem = item.firstChild;
-    let placeForItem = CustomizableUI.getPlaceForItem(item);
-    let isRemovable = placeForItem == "palette" ||
-                      CustomizableUI.isWidgetRemovable(draggedItem);
-    if (item.classList.contains(kPlaceholderClass) || !isRemovable) {
-      return;
-    }
-
-    let dt = aEvent.dataTransfer;
-    let documentId = aEvent.target.ownerDocument.documentElement.id;
-    let isInToolbar = placeForItem == "toolbar";
-
-    dt.mozSetDataAt(kDragDataTypePrefix + documentId, draggedItem.id, 0);
-    dt.effectAllowed = "move";
-
-    let itemRect = draggedItem.getBoundingClientRect();
-    let itemCenter = {x: itemRect.left + itemRect.width / 2,
-                      y: itemRect.top + itemRect.height / 2};
-    this._dragOffset = {x: aEvent.clientX - itemCenter.x,
-                        y: aEvent.clientY - itemCenter.y};
-
-    gDraggingInToolbars = new Set();
-
-    // Hack needed so that the dragimage will still show the
-    // item as it appeared before it was hidden.
-    this._initializeDragAfterMove = function() {
-      // For automated tests, we sometimes start exiting customization mode
-      // before this fires, which leaves us with placeholders inserted after
-      // we've exited. So we need to check that we are indeed customizing.
-      if (this._customizing && !this._transitioning) {
-        item.hidden = true;
-        this._showPanelCustomizationPlaceholders();
-        DragPositionManager.start(this.window);
-        if (item.nextSibling) {
-          this._setDragActive(item.nextSibling, "before", draggedItem.id, isInToolbar);
-          this._dragOverItem = item.nextSibling;
-        } else if (isInToolbar && item.previousSibling) {
-          this._setDragActive(item.previousSibling, "after", draggedItem.id, isInToolbar);
-          this._dragOverItem = item.previousSibling;
-        }
-      }
-      this._initializeDragAfterMove = null;
-      this.window.clearTimeout(this._dragInitializeTimeout);
-    }.bind(this);
-    this._dragInitializeTimeout = this.window.setTimeout(this._initializeDragAfterMove, 0);
-  },
-
-  _onDragOver: function(aEvent) {
-    if (this._isUnwantedDragDrop(aEvent)) {
-      return;
-    }
-    if (this._initializeDragAfterMove) {
-      this._initializeDragAfterMove();
-    }
-
-    __dumpDragData(aEvent);
-
-    let document = aEvent.target.ownerDocument;
-    let documentId = document.documentElement.id;
-    if (!aEvent.dataTransfer.mozTypesAt(0)) {
-      return;
-    }
-
-    let draggedItemId =
-      aEvent.dataTransfer.mozGetDataAt(kDragDataTypePrefix + documentId, 0);
-    let draggedWrapper = document.getElementById("wrapper-" + draggedItemId);
-    let targetArea = this._getCustomizableParent(aEvent.currentTarget);
-    let originArea = this._getCustomizableParent(draggedWrapper);
-
-    // Do nothing if the target or origin are not customizable.
-    if (!targetArea || !originArea) {
-      return;
-    }
-
-    // Do nothing if the widget is not allowed to be removed.
-    if (targetArea.id == kPaletteId &&
-       !CustomizableUI.isWidgetRemovable(draggedItemId)) {
-      return;
-    }
-
-    // Do nothing if the widget is not allowed to move to the target area.
-    if (targetArea.id != kPaletteId &&
-        !CustomizableUI.canWidgetMoveToArea(draggedItemId, targetArea.id)) {
-      return;
-    }
-
-    let targetIsToolbar = CustomizableUI.getAreaType(targetArea.id) == "toolbar";
-    let targetNode = this._getDragOverNode(aEvent, targetArea, targetIsToolbar, draggedItemId);
-
-    // We need to determine the place that the widget is being dropped in
-    // the target.
-    let dragOverItem, dragValue;
-    if (targetNode == targetArea.customizationTarget) {
-      // We'll assume if the user is dragging directly over the target, that
-      // they're attempting to append a child to that target.
-      dragOverItem = (targetIsToolbar ? this._findVisiblePreviousSiblingNode(targetNode.lastChild) :
-                                        targetNode.lastChild) || targetNode;
-      dragValue = "after";
-    } else {
-      let targetParent = targetNode.parentNode;
-      let position = Array.indexOf(targetParent.children, targetNode);
-      if (position == -1) {
-        dragOverItem = targetIsToolbar ? this._findVisiblePreviousSiblingNode(targetNode.lastChild) :
-                                         targetParent.lastChild;
-        dragValue = "after";
-      } else {
-        dragOverItem = targetParent.children[position];
-        if (!targetIsToolbar) {
-          dragValue = "before";
-        } else {
-          // Check if the aDraggedItem is hovered past the first half of dragOverItem
-          let window = dragOverItem.ownerGlobal;
-          let direction = window.getComputedStyle(dragOverItem, null).direction;
-          let itemRect = dragOverItem.getBoundingClientRect();
-          let dropTargetCenter = itemRect.left + (itemRect.width / 2);
-          let existingDir = dragOverItem.getAttribute("dragover");
-          if ((existingDir == "before") == (direction == "ltr")) {
-            dropTargetCenter += (parseInt(dragOverItem.style.borderLeftWidth) || 0) / 2;
-          } else {
-            dropTargetCenter -= (parseInt(dragOverItem.style.borderRightWidth) || 0) / 2;
-          }
-          let before = direction == "ltr" ? aEvent.clientX < dropTargetCenter : aEvent.clientX > dropTargetCenter;
-          dragValue = before ? "before" : "after";
-        }
-      }
-    }
-
-    if (this._dragOverItem && dragOverItem != this._dragOverItem) {
-      this._cancelDragActive(this._dragOverItem, dragOverItem);
-    }
-
-    if (dragOverItem != this._dragOverItem || dragValue != dragOverItem.getAttribute("dragover")) {
-      if (dragOverItem != targetArea.customizationTarget) {
-        this._setDragActive(dragOverItem, dragValue, draggedItemId, targetIsToolbar);
-      } else if (targetIsToolbar) {
-        this._updateToolbarCustomizationOutline(this.window, targetArea);
-      }
-      this._dragOverItem = dragOverItem;
-    }
-
-    aEvent.preventDefault();
-    aEvent.stopPropagation();
-  },
-
-  _onDragDrop: function(aEvent) {
-    if (this._isUnwantedDragDrop(aEvent)) {
-      return;
-    }
-
-    __dumpDragData(aEvent);
-    this._initializeDragAfterMove = null;
-    this.window.clearTimeout(this._dragInitializeTimeout);
-
-    let targetArea = this._getCustomizableParent(aEvent.currentTarget);
-    let document = aEvent.target.ownerDocument;
-    let documentId = document.documentElement.id;
-    let draggedItemId =
-      aEvent.dataTransfer.mozGetDataAt(kDragDataTypePrefix + documentId, 0);
-    let draggedWrapper = document.getElementById("wrapper-" + draggedItemId);
-    let originArea = this._getCustomizableParent(draggedWrapper);
-    if (this._dragSizeMap) {
-      this._dragSizeMap = new WeakMap();
-    }
-    // Do nothing if the target area or origin area are not customizable.
-    if (!targetArea || !originArea) {
-      return;
-    }
-    let targetNode = this._dragOverItem;
-    let dropDir = targetNode.getAttribute("dragover");
-    // Need to insert *after* this node if we promised the user that:
-    if (targetNode != targetArea && dropDir == "after") {
-      if (targetNode.nextSibling) {
-        targetNode = targetNode.nextSibling;
-      } else {
-        targetNode = targetArea;
-      }
-    }
-    // If the target node is a placeholder, get its sibling as the real target.
-    while (targetNode.classList.contains(kPlaceholderClass) && targetNode.nextSibling) {
-      targetNode = targetNode.nextSibling;
-    }
-    if (targetNode.tagName == "toolbarpaletteitem") {
-      targetNode = targetNode.firstChild;
-    }
-
-    this._cancelDragActive(this._dragOverItem, null, true);
-    this._removePanelCustomizationPlaceholders();
-
-    try {
-      this._applyDrop(aEvent, targetArea, originArea, draggedItemId, targetNode);
-    } catch (ex) {
-      log.error(ex, ex.stack);
-    }
-
-    this._showPanelCustomizationPlaceholders();
-  },
-
-  _applyDrop: function(aEvent, aTargetArea, aOriginArea, aDraggedItemId, aTargetNode) {
-    let document = aEvent.target.ownerDocument;
-    let draggedItem = document.getElementById(aDraggedItemId);
-    draggedItem.hidden = false;
-    draggedItem.removeAttribute("mousedown");
-
-    // Do nothing if the target was dropped onto itself (ie, no change in area
-    // or position).
-    if (draggedItem == aTargetNode) {
-      return;
-    }
-
-    // Is the target area the customization palette?
-    if (aTargetArea.id == kPaletteId) {
-      // Did we drag from outside the palette?
-      if (aOriginArea.id !== kPaletteId) {
-        if (!CustomizableUI.isWidgetRemovable(aDraggedItemId)) {
-          return;
-        }
-
-        CustomizableUI.removeWidgetFromArea(aDraggedItemId);
-        BrowserUITelemetry.countCustomizationEvent("remove");
-        // Special widgets are removed outright, we can return here:
-        if (CustomizableUI.isSpecialWidget(aDraggedItemId)) {
-          return;
-        }
-      }
-      draggedItem = draggedItem.parentNode;
-
-      // If the target node is the palette itself, just append
-      if (aTargetNode == this.visiblePalette) {
-        this.visiblePalette.appendChild(draggedItem);
-      } else {
-        // The items in the palette are wrapped, so we need the target node's parent here:
-        this.visiblePalette.insertBefore(draggedItem, aTargetNode.parentNode);
-      }
-      if (aOriginArea.id !== kPaletteId) {
-        // The dragend event already fires when the item moves within the palette.
-        this._onDragEnd(aEvent);
-      }
-      return;
-    }
-
-    if (!CustomizableUI.canWidgetMoveToArea(aDraggedItemId, aTargetArea.id)) {
-      return;
-    }
-
-    // Skipintoolbarset items won't really be moved:
-    if (draggedItem.getAttribute("skipintoolbarset") == "true") {
-      // These items should never leave their area:
-      if (aTargetArea != aOriginArea) {
-        return;
-      }
-      let place = draggedItem.parentNode.getAttribute("place");
-      this.unwrapToolbarItem(draggedItem.parentNode);
-      if (aTargetNode == aTargetArea.customizationTarget) {
-        aTargetArea.customizationTarget.appendChild(draggedItem);
-      } else {
-        this.unwrapToolbarItem(aTargetNode.parentNode);
-        aTargetArea.customizationTarget.insertBefore(draggedItem, aTargetNode);
-        this.wrapToolbarItem(aTargetNode, place);
-      }
-      this.wrapToolbarItem(draggedItem, place);
-      BrowserUITelemetry.countCustomizationEvent("move");
-      return;
-    }
-
-    // Is the target the customization area itself? If so, we just add the
-    // widget to the end of the area.
-    if (aTargetNode == aTargetArea.customizationTarget) {
-      CustomizableUI.addWidgetToArea(aDraggedItemId, aTargetArea.id);
-      // For the purposes of BrowserUITelemetry, we consider both moving a widget
-      // within the same area, and adding a widget from one area to another area
-      // as a "move". An "add" is only when we move an item from the palette into
-      // an area.
-      let custEventType = aOriginArea.id == kPaletteId ? "add" : "move";
-      BrowserUITelemetry.countCustomizationEvent(custEventType);
-      this._onDragEnd(aEvent);
-      return;
-    }
-
-    // We need to determine the place that the widget is being dropped in
-    // the target.
-    let placement;
-    let itemForPlacement = aTargetNode;
-    // Skip the skipintoolbarset items when determining the place of the item:
-    while (itemForPlacement && itemForPlacement.getAttribute("skipintoolbarset") == "true" &&
-           itemForPlacement.parentNode &&
-           itemForPlacement.parentNode.nodeName == "toolbarpaletteitem") {
-      itemForPlacement = itemForPlacement.parentNode.nextSibling;
-      if (itemForPlacement && itemForPlacement.nodeName == "toolbarpaletteitem") {
-        itemForPlacement = itemForPlacement.firstChild;
-      }
-    }
-    if (itemForPlacement && !itemForPlacement.classList.contains(kPlaceholderClass)) {
-      let targetNodeId = (itemForPlacement.nodeName == "toolbarpaletteitem") ?
-                            itemForPlacement.firstChild && itemForPlacement.firstChild.id :
-                            itemForPlacement.id;
-      placement = CustomizableUI.getPlacementOfWidget(targetNodeId);
-    }
-    if (!placement) {
-      log.debug("Could not get a position for " + aTargetNode.nodeName + "#" + aTargetNode.id + "." + aTargetNode.className);
-    }
-    let position = placement ? placement.position : null;
-
-    // Is the target area the same as the origin? Since we've already handled
-    // the possibility that the target is the customization palette, we know
-    // that the widget is moving within a customizable area.
-    if (aTargetArea == aOriginArea) {
-      CustomizableUI.moveWidgetWithinArea(aDraggedItemId, position);
-    } else {
-      CustomizableUI.addWidgetToArea(aDraggedItemId, aTargetArea.id, position);
-    }
-
-    this._onDragEnd(aEvent);
-
-    // For BrowserUITelemetry, an "add" is only when we move an item from the palette
-    // into an area. Otherwise, it's a move.
-    let custEventType = aOriginArea.id == kPaletteId ? "add" : "move";
-    BrowserUITelemetry.countCustomizationEvent(custEventType);
-
-    // If we dropped onto a skipintoolbarset item, manually correct the drop location:
-    if (aTargetNode != itemForPlacement) {
-      let draggedWrapper = draggedItem.parentNode;
-      let container = draggedWrapper.parentNode;
-      container.insertBefore(draggedWrapper, aTargetNode.parentNode);
-    }
-  },
-
-  _onDragExit: function(aEvent) {
-    if (this._isUnwantedDragDrop(aEvent)) {
-      return;
-    }
-
-    __dumpDragData(aEvent);
-
-    // When leaving customization areas, cancel the drag on the last dragover item
-    // We've attached the listener to areas, so aEvent.currentTarget will be the area.
-    // We don't care about dragexit events fired on descendants of the area,
-    // so we check that the event's target is the same as the area to which the listener
-    // was attached.
-    if (this._dragOverItem && aEvent.target == aEvent.currentTarget) {
-      this._cancelDragActive(this._dragOverItem);
-      this._dragOverItem = null;
-    }
-  },
-
-  /**
-   * To workaround bug 460801 we manually forward the drop event here when dragend wouldn't be fired.
-   */
-  _onDragEnd: function(aEvent) {
-    if (this._isUnwantedDragDrop(aEvent)) {
-      return;
-    }
-    this._initializeDragAfterMove = null;
-    this.window.clearTimeout(this._dragInitializeTimeout);
-    __dumpDragData(aEvent, "_onDragEnd");
-
-    let document = aEvent.target.ownerDocument;
-    document.documentElement.removeAttribute("customizing-movingItem");
-
-    let documentId = document.documentElement.id;
-    if (!aEvent.dataTransfer.mozTypesAt(0)) {
-      return;
-    }
-
-    let draggedItemId =
-      aEvent.dataTransfer.mozGetDataAt(kDragDataTypePrefix + documentId, 0);
-
-    let draggedWrapper = document.getElementById("wrapper-" + draggedItemId);
-
-    // DraggedWrapper might no longer available if a widget node is
-    // destroyed after starting (but before stopping) a drag.
-    if (draggedWrapper) {
-      draggedWrapper.hidden = false;
-      draggedWrapper.removeAttribute("mousedown");
-    }
-
-    if (this._dragOverItem) {
-      this._cancelDragActive(this._dragOverItem);
-      this._dragOverItem = null;
-    }
-    this._updateToolbarCustomizationOutline(this.window);
-    this._showPanelCustomizationPlaceholders();
-    DragPositionManager.stop();
-  },
-
-  _isUnwantedDragDrop: function(aEvent) {
-    // The simulated events generated by synthesizeDragStart/synthesizeDrop in
-    // mochitests are used only for testing whether the right data is being put
-    // into the dataTransfer. Neither cause a real drop to occur, so they don't
-    // set the source node. There isn't a means of testing real drag and drops,
-    // so this pref skips the check but it should only be set by test code.
-    if (this._skipSourceNodeCheck) {
-      return false;
-    }
-
-    /* Discard drag events that originated from a separate window to
-       prevent content->chrome privilege escalations. */
-    let mozSourceNode = aEvent.dataTransfer.mozSourceNode;
-    // mozSourceNode is null in the dragStart event handler or if
-    // the drag event originated in an external application.
-    return !mozSourceNode ||
-           mozSourceNode.ownerGlobal != this.window;
-  },
-
-  _setDragActive: function(aItem, aValue, aDraggedItemId, aInToolbar) {
-    if (!aItem) {
-      return;
-    }
-
-    if (aItem.getAttribute("dragover") != aValue) {
-      aItem.setAttribute("dragover", aValue);
-
-      let window = aItem.ownerGlobal;
-      let draggedItem = window.document.getElementById(aDraggedItemId);
-      if (!aInToolbar) {
-        this._setGridDragActive(aItem, draggedItem, aValue);
-      } else {
-        let targetArea = this._getCustomizableParent(aItem);
-        this._updateToolbarCustomizationOutline(window, targetArea);
-        let makeSpaceImmediately = false;
-        if (!gDraggingInToolbars.has(targetArea.id)) {
-          gDraggingInToolbars.add(targetArea.id);
-          let draggedWrapper = this.document.getElementById("wrapper-" + aDraggedItemId);
-          let originArea = this._getCustomizableParent(draggedWrapper);
-          makeSpaceImmediately = originArea == targetArea;
-        }
-        // Calculate width of the item when it'd be dropped in this position
-        let width = this._getDragItemSize(aItem, draggedItem).width;
-        let direction = window.getComputedStyle(aItem).direction;
-        let prop, otherProp;
-        // If we're inserting before in ltr, or after in rtl:
-        if ((aValue == "before") == (direction == "ltr")) {
-          prop = "borderLeftWidth";
-          otherProp = "border-right-width";
-        } else {
-          // otherwise:
-          prop = "borderRightWidth";
-          otherProp = "border-left-width";
-        }
-        if (makeSpaceImmediately) {
-          aItem.setAttribute("notransition", "true");
-        }
-        aItem.style[prop] = width + 'px';
-        aItem.style.removeProperty(otherProp);
-        if (makeSpaceImmediately) {
-          // Force a layout flush:
-          aItem.getBoundingClientRect();
-          aItem.removeAttribute("notransition");
-        }
-      }
-    }
-  },
-  _cancelDragActive: function(aItem, aNextItem, aNoTransition) {
-    this._updateToolbarCustomizationOutline(aItem.ownerGlobal);
-    let currentArea = this._getCustomizableParent(aItem);
-    if (!currentArea) {
-      return;
-    }
-    let isToolbar = CustomizableUI.getAreaType(currentArea.id) == "toolbar";
-    if (isToolbar) {
-      if (aNoTransition) {
-        aItem.setAttribute("notransition", "true");
-      }
-      aItem.removeAttribute("dragover");
-      // Remove both property values in the case that the end padding
-      // had been set.
-      aItem.style.removeProperty("border-left-width");
-      aItem.style.removeProperty("border-right-width");
-      if (aNoTransition) {
-        // Force a layout flush:
-        aItem.getBoundingClientRect();
-        aItem.removeAttribute("notransition");
-      }
-    } else  {
-      aItem.removeAttribute("dragover");
-      if (aNextItem) {
-        let nextArea = this._getCustomizableParent(aNextItem);
-        if (nextArea == currentArea) {
-          // No need to do anything if we're still dragging in this area:
-          return;
-        }
-      }
-      // Otherwise, clear everything out:
-      let positionManager = DragPositionManager.getManagerForArea(currentArea);
-      positionManager.clearPlaceholders(currentArea, aNoTransition);
-    }
-  },
-
-  _setGridDragActive: function(aDragOverNode, aDraggedItem, aValue) {
-    let targetArea = this._getCustomizableParent(aDragOverNode);
-    let draggedWrapper = this.document.getElementById("wrapper-" + aDraggedItem.id);
-    let originArea = this._getCustomizableParent(draggedWrapper);
-    let positionManager = DragPositionManager.getManagerForArea(targetArea);
-    let draggedSize = this._getDragItemSize(aDragOverNode, aDraggedItem);
-    let isWide = aDraggedItem.classList.contains(CustomizableUI.WIDE_PANEL_CLASS);
-    positionManager.insertPlaceholder(targetArea, aDragOverNode, isWide, draggedSize,
-                                      originArea == targetArea);
-  },
-
-  _getDragItemSize: function(aDragOverNode, aDraggedItem) {
-    // Cache it good, cache it real good.
-    if (!this._dragSizeMap)
-      this._dragSizeMap = new WeakMap();
-    if (!this._dragSizeMap.has(aDraggedItem))
-      this._dragSizeMap.set(aDraggedItem, new WeakMap());
-    let itemMap = this._dragSizeMap.get(aDraggedItem);
-    let targetArea = this._getCustomizableParent(aDragOverNode);
-    let currentArea = this._getCustomizableParent(aDraggedItem);
-    // Return the size for this target from cache, if it exists.
-    let size = itemMap.get(targetArea);
-    if (size)
-      return size;
-
-    // Calculate size of the item when it'd be dropped in this position.
-    let currentParent = aDraggedItem.parentNode;
-    let currentSibling = aDraggedItem.nextSibling;
-    const kAreaType = "cui-areatype";
-    let areaType, currentType;
-
-    if (targetArea != currentArea) {
-      // Move the widget temporarily next to the placeholder.
-      aDragOverNode.parentNode.insertBefore(aDraggedItem, aDragOverNode);
-      // Update the node's areaType.
-      areaType = CustomizableUI.getAreaType(targetArea.id);
-      currentType = aDraggedItem.hasAttribute(kAreaType) &&
-                    aDraggedItem.getAttribute(kAreaType);
-      if (areaType)
-        aDraggedItem.setAttribute(kAreaType, areaType);
-      this.wrapToolbarItem(aDraggedItem, areaType || "palette");
-      CustomizableUI.onWidgetDrag(aDraggedItem.id, targetArea.id);
-    } else {
-      aDraggedItem.parentNode.hidden = false;
-    }
-
-    // Fetch the new size.
-    let rect = aDraggedItem.parentNode.getBoundingClientRect();
-    size = {width: rect.width, height: rect.height};
-    // Cache the found value of size for this target.
-    itemMap.set(targetArea, size);
-
-    if (targetArea != currentArea) {
-      this.unwrapToolbarItem(aDraggedItem.parentNode);
-      // Put the item back into its previous position.
-      currentParent.insertBefore(aDraggedItem, currentSibling);
-      // restore the areaType
-      if (areaType) {
-        if (currentType === false)
-          aDraggedItem.removeAttribute(kAreaType);
-        else
-          aDraggedItem.setAttribute(kAreaType, currentType);
-      }
-      this.createOrUpdateWrapper(aDraggedItem, null, true);
-      CustomizableUI.onWidgetDrag(aDraggedItem.id);
-    } else {
-      aDraggedItem.parentNode.hidden = true;
-    }
-    return size;
-  },
-
-  _getCustomizableParent: function(aElement) {
-    let areas = CustomizableUI.areas;
-    areas.push(kPaletteId);
-    while (aElement) {
-      if (areas.indexOf(aElement.id) != -1) {
-        return aElement;
-      }
-      aElement = aElement.parentNode;
-    }
-    return null;
-  },
-
-  _getDragOverNode: function(aEvent, aAreaElement, aInToolbar, aDraggedItemId) {
-    let expectedParent = aAreaElement.customizationTarget || aAreaElement;
-    // Our tests are stupid. Cope:
-    if (!aEvent.clientX  && !aEvent.clientY) {
-      return aEvent.target;
-    }
-    // Offset the drag event's position with the offset to the center of
-    // the thing we're dragging
-    let dragX = aEvent.clientX - this._dragOffset.x;
-    let dragY = aEvent.clientY - this._dragOffset.y;
-
-    // Ensure this is within the container
-    let boundsContainer = expectedParent;
-    // NB: because the panel UI itself is inside a scrolling container, we need
-    // to use the parent bounds (otherwise, if the panel UI is scrolled down,
-    // the numbers we get are in window coordinates which leads to various kinds
-    // of weirdness)
-    if (boundsContainer == this.panelUIContents) {
-      boundsContainer = boundsContainer.parentNode;
-    }
-    let bounds = boundsContainer.getBoundingClientRect();
-    dragX = Math.min(bounds.right, Math.max(dragX, bounds.left));
-    dragY = Math.min(bounds.bottom, Math.max(dragY, bounds.top));
-
-    let targetNode;
-    if (aInToolbar) {
-      targetNode = aAreaElement.ownerDocument.elementFromPoint(dragX, dragY);
-      while (targetNode && targetNode.parentNode != expectedParent) {
-        targetNode = targetNode.parentNode;
-      }
-    } else {
-      let positionManager = DragPositionManager.getManagerForArea(aAreaElement);
-      // Make it relative to the container:
-      dragX -= bounds.left;
-      // NB: but if we're in the panel UI, we need to use the actual panel
-      // contents instead of the scrolling container to determine our origin
-      // offset against:
-      if (expectedParent == this.panelUIContents) {
-        dragY -= this.panelUIContents.getBoundingClientRect().top;
-      } else {
-        dragY -= bounds.top;
-      }
-      // Find the closest node:
-      targetNode = positionManager.find(aAreaElement, dragX, dragY, aDraggedItemId);
-    }
-    return targetNode || aEvent.target;
-  },
-
-  _onMouseDown: function(aEvent) {
-    log.debug("_onMouseDown");
-    if (aEvent.button != 0) {
-      return;
-    }
-    let doc = aEvent.target.ownerDocument;
-    doc.documentElement.setAttribute("customizing-movingItem", true);
-    let item = this._getWrapper(aEvent.target);
-    if (item && !item.classList.contains(kPlaceholderClass) &&
-        item.getAttribute("removable") == "true") {
-      item.setAttribute("mousedown", "true");
-    }
-  },
-
-  _onMouseUp: function(aEvent) {
-    log.debug("_onMouseUp");
-    if (aEvent.button != 0) {
-      return;
-    }
-    let doc = aEvent.target.ownerDocument;
-    doc.documentElement.removeAttribute("customizing-movingItem");
-    let item = this._getWrapper(aEvent.target);
-    if (item) {
-      item.removeAttribute("mousedown");
-    }
-  },
-
-  _getWrapper: function(aElement) {
-    while (aElement && aElement.localName != "toolbarpaletteitem") {
-      if (aElement.localName == "toolbar")
-        return null;
-      aElement = aElement.parentNode;
-    }
-    return aElement;
-  },
-
-  _showPanelCustomizationPlaceholders: function() {
-    let doc = this.document;
-    let contents = this.panelUIContents;
-    let narrowItemsAfterWideItem = 0;
-    let node = contents.lastChild;
-    while (node && !node.classList.contains(CustomizableUI.WIDE_PANEL_CLASS) &&
-           (!node.firstChild || !node.firstChild.classList.contains(CustomizableUI.WIDE_PANEL_CLASS))) {
-      if (!node.hidden && !node.classList.contains(kPlaceholderClass)) {
-        narrowItemsAfterWideItem++;
-      }
-      node = node.previousSibling;
-    }
-
-    let orphanedItems = narrowItemsAfterWideItem % CustomizableUI.PANEL_COLUMN_COUNT;
-    let placeholders = CustomizableUI.PANEL_COLUMN_COUNT - orphanedItems;
-
-    let currentPlaceholderCount = contents.querySelectorAll("." + kPlaceholderClass).length;
-    if (placeholders > currentPlaceholderCount) {
-      while (placeholders-- > currentPlaceholderCount) {
-        let placeholder = doc.createElement("toolbarpaletteitem");
-        placeholder.classList.add(kPlaceholderClass);
-        // XXXjaws The toolbarbutton child here is only necessary to get
-        //  the styling right here.
-        let placeholderChild = doc.createElement("toolbarbutton");
-        placeholderChild.classList.add(kPlaceholderClass + "-child");
-        placeholder.appendChild(placeholderChild);
-        contents.appendChild(placeholder);
-      }
-    } else if (placeholders < currentPlaceholderCount) {
-      while (placeholders++ < currentPlaceholderCount) {
-        contents.querySelectorAll("." + kPlaceholderClass)[0].remove();
-      }
-    }
-  },
-
-  _removePanelCustomizationPlaceholders: function() {
-    let contents = this.panelUIContents;
-    let oldPlaceholders = contents.getElementsByClassName(kPlaceholderClass);
-    while (oldPlaceholders.length) {
-      contents.removeChild(oldPlaceholders[0]);
-    }
-  },
-
-  /**
-   * Update toolbar customization targets during drag events to add or remove
-   * outlines to indicate that an area is customizable.
-   *
-   * @param aWindow                       The XUL window in which outlines should be updated.
-   * @param {Element} [aToolbarArea=null] The element of the customizable toolbar area to add the
-   *                                      outline to. If aToolbarArea is falsy, the outline will be
-   *                                      removed from all toolbar areas.
-   */
-  _updateToolbarCustomizationOutline: function(aWindow, aToolbarArea = null) {
-    // Remove the attribute from existing customization targets
-    for (let area of CustomizableUI.areas) {
-      if (CustomizableUI.getAreaType(area) != CustomizableUI.TYPE_TOOLBAR) {
-        continue;
-      }
-      let target = CustomizableUI.getCustomizeTargetForArea(area, aWindow);
-      target.removeAttribute("customizing-dragovertarget");
-    }
-
-    // Now set the attribute on the desired target
-    if (aToolbarArea) {
-      if (CustomizableUI.getAreaType(aToolbarArea.id) != CustomizableUI.TYPE_TOOLBAR)
-        return;
-      let target = CustomizableUI.getCustomizeTargetForArea(aToolbarArea.id, aWindow);
-      target.setAttribute("customizing-dragovertarget", true);
-    }
-  },
-
-  _findVisiblePreviousSiblingNode: function(aReferenceNode) {
-    while (aReferenceNode &&
-           aReferenceNode.localName == "toolbarpaletteitem" &&
-           aReferenceNode.firstChild.hidden) {
-      aReferenceNode = aReferenceNode.previousSibling;
-    }
-    return aReferenceNode;
-  },
-};
-
-function __dumpDragData(aEvent, caller) {
-  if (!gDebug) {
-    return;
-  }
-  let str = "Dumping drag data (" + (caller ? caller + " in " : "") + "CustomizeMode.jsm) {\n";
-  str += "  type: " + aEvent["type"] + "\n";
-  for (let el of ["target", "currentTarget", "relatedTarget"]) {
-    if (aEvent[el]) {
-      str += "  " + el + ": " + aEvent[el] + "(localName=" + aEvent[el].localName + "; id=" + aEvent[el].id + ")\n";
-    }
-  }
-  for (let prop in aEvent.dataTransfer) {
-    if (typeof aEvent.dataTransfer[prop] != "function") {
-      str += "  dataTransfer[" + prop + "]: " + aEvent.dataTransfer[prop] + "\n";
-    }
-  }
-  str += "}";
-  log.debug(str);
-}
-
-function dispatchFunction(aFunc) {
-  Services.tm.currentThread.dispatch(aFunc, Ci.nsIThread.DISPATCH_NORMAL);
-}
diff --git a/browser/components/customizableui/DragPositionManager.jsm b/browser/components/customizableui/DragPositionManager.jsm
deleted file mode 100644
index 1b4eb59dc..000000000
--- a/browser/components/customizableui/DragPositionManager.jsm
+++ /dev/null
@@ -1,420 +0,0 @@
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-"use strict";
-
-Components.utils.import("resource:///modules/CustomizableUI.jsm");
-
-var gManagers = new WeakMap();
-
-const kPaletteId = "customization-palette";
-const kPlaceholderClass = "panel-customization-placeholder";
-
-this.EXPORTED_SYMBOLS = ["DragPositionManager"];
-
-function AreaPositionManager(aContainer) {
-  // Caching the direction and bounds of the container for quick access later:
-  let window = aContainer.ownerGlobal;
-  this._dir = window.getComputedStyle(aContainer).direction;
-  let containerRect = aContainer.getBoundingClientRect();
-  this._containerInfo = {
-    left: containerRect.left,
-    right: containerRect.right,
-    top: containerRect.top,
-    width: containerRect.width
-  };
-  this._inPanel = aContainer.id == CustomizableUI.AREA_PANEL;
-  this._horizontalDistance = null;
-  this.update(aContainer);
-}
-
-AreaPositionManager.prototype = {
-  _nodePositionStore: null,
-  _wideCache: null,
-
-  update: function(aContainer) {
-    this._nodePositionStore = new WeakMap();
-    this._wideCache = new Set();
-    let last = null;
-    let singleItemHeight;
-    for (let child of aContainer.children) {
-      if (child.hidden) {
-        continue;
-      }
-      let isNodeWide = this._checkIfWide(child);
-      if (isNodeWide) {
-        this._wideCache.add(child.id);
-      }
-      let coordinates = this._lazyStoreGet(child);
-      // We keep a baseline horizontal distance between non-wide nodes around
-      // for use when we can't compare with previous/next nodes
-      if (!this._horizontalDistance && last && !isNodeWide) {
-        this._horizontalDistance = coordinates.left - last.left;
-      }
-      // We also keep the basic height of non-wide items for use below:
-      if (!isNodeWide && !singleItemHeight) {
-        singleItemHeight = coordinates.height;
-      }
-      last = !isNodeWide ? coordinates : null;
-    }
-    if (this._inPanel) {
-      this._heightToWidthFactor = CustomizableUI.PANEL_COLUMN_COUNT;
-    } else {
-      this._heightToWidthFactor = this._containerInfo.width / singleItemHeight;
-    }
-  },
-
-  /**
-   * Find the closest node in the container given the coordinates.
-   * "Closest" is defined in a somewhat strange manner: we prefer nodes
-   * which are in the same row over nodes that are in a different row.
-   * In order to implement this, we use a weighted cartesian distance
-   * where dy is more heavily weighted by a factor corresponding to the
-   * ratio between the container's width and the height of its elements.
-   */
-  find: function(aContainer, aX, aY, aDraggedItemId) {
-    let closest = null;
-    let minCartesian = Number.MAX_VALUE;
-    let containerX = this._containerInfo.left;
-    let containerY = this._containerInfo.top;
-    for (let node of aContainer.children) {
-      let coordinates = this._lazyStoreGet(node);
-      let offsetX = coordinates.x - containerX;
-      let offsetY = coordinates.y - containerY;
-      let hDiff = offsetX - aX;
-      let vDiff = offsetY - aY;
-      // For wide widgets, we're always going to be further from the center
-      // horizontally. Compensate:
-      if (this.isWide(node)) {
-        hDiff /= CustomizableUI.PANEL_COLUMN_COUNT;
-      }
-      // Then compensate for the height/width ratio so that we prefer items
-      // which are in the same row:
-      hDiff /= this._heightToWidthFactor;
-
-      let cartesianDiff = hDiff * hDiff + vDiff * vDiff;
-      if (cartesianDiff < minCartesian) {
-        minCartesian = cartesianDiff;
-        closest = node;
-      }
-    }
-
-    // Now correct this node based on what we're dragging
-    if (closest) {
-      let doc = aContainer.ownerDocument;
-      let draggedItem = doc.getElementById(aDraggedItemId);
-      // If dragging a wide item, always pick the first item in a row:
-      if (this._inPanel && draggedItem &&
-          draggedItem.classList.contains(CustomizableUI.WIDE_PANEL_CLASS)) {
-        return this._firstInRow(closest);
-      }
-      let targetBounds = this._lazyStoreGet(closest);
-      let farSide = this._dir == "ltr" ? "right" : "left";
-      let outsideX = targetBounds[farSide];
-      // Check if we're closer to the next target than to this one:
-      // Only move if we're not targeting a node in a different row:
-      if (aY > targetBounds.top && aY < targetBounds.bottom) {
-        if ((this._dir == "ltr" && aX > outsideX) ||
-            (this._dir == "rtl" && aX < outsideX)) {
-          return closest.nextSibling || aContainer;
-        }
-      }
-    }
-    return closest;
-  },
-
-  /**
-   * "Insert" a "placeholder" by shifting the subsequent children out of the
-   * way. We go through all the children, and shift them based on the position
-   * they would have if we had inserted something before aBefore. We use CSS
-   * transforms for this, which are CSS transitioned.
-   */
-  insertPlaceholder: function(aContainer, aBefore, aWide, aSize, aIsFromThisArea) {
-    let isShifted = false;
-    let shiftDown = aWide;
-    for (let child of aContainer.children) {
-      // Don't need to shift hidden nodes:
-      if (child.getAttribute("hidden") == "true") {
-        continue;
-      }
-      // If this is the node before which we're inserting, start shifting
-      // everything that comes after. One exception is inserting at the end
-      // of the menupanel, in which case we do not shift the placeholders:
-      if (child == aBefore && !child.classList.contains(kPlaceholderClass)) {
-        isShifted = true;
-        // If the node before which we're inserting is wide, we should
-        // shift everything one row down:
-        if (!shiftDown && this.isWide(child)) {
-          shiftDown = true;
-        }
-      }
-      // If we're moving items before a wide node that were already there,
-      // it's possible it's not necessary to shift nodes
-      // including & after the wide node.
-      if (this.__undoShift) {
-        isShifted = false;
-      }
-      if (isShifted) {
-        // Conversely, if we're adding something before a wide node, for
-        // simplicity's sake we move everything including the wide node down:
-        if (this.__moveDown) {
-          shiftDown = true;
-        }
-        if (aIsFromThisArea && !this._lastPlaceholderInsertion) {
-          child.setAttribute("notransition", "true");
-        }
-        // Determine the CSS transform based on the next node:
-        child.style.transform = this._getNextPos(child, shiftDown, aSize);
-      } else {
-        // If we're not shifting this node, reset the transform
-        child.style.transform = "";
-      }
-    }
-    if (aContainer.lastChild && aIsFromThisArea &&
-        !this._lastPlaceholderInsertion) {
-      // Flush layout:
-      aContainer.lastChild.getBoundingClientRect();
-      // then remove all the [notransition]
-      for (let child of aContainer.children) {
-        child.removeAttribute("notransition");
-      }
-    }
-    delete this.__moveDown;
-    delete this.__undoShift;
-    this._lastPlaceholderInsertion = aBefore;
-  },
-
-  isWide: function(aNode) {
-    return this._wideCache.has(aNode.id);
-  },
-
-  _checkIfWide: function(aNode) {
-    return this._inPanel && aNode && aNode.firstChild &&
-           aNode.firstChild.classList.contains(CustomizableUI.WIDE_PANEL_CLASS);
-  },
-
-  /**
-   * Reset all the transforms in this container, optionally without
-   * transitioning them.
-   * @param aContainer    the container in which to reset transforms
-   * @param aNoTransition if truthy, adds a notransition attribute to the node
-   *                      while resetting the transform.
-   */
-  clearPlaceholders: function(aContainer, aNoTransition) {
-    for (let child of aContainer.children) {
-      if (aNoTransition) {
-        child.setAttribute("notransition", true);
-      }
-      child.style.transform = "";
-      if (aNoTransition) {
-        // Need to force a reflow otherwise this won't work.
-        child.getBoundingClientRect();
-        child.removeAttribute("notransition");
-      }
-    }
-    // We snapped back, so we can assume there's no more
-    // "last" placeholder insertion point to keep track of.
-    if (aNoTransition) {
-      this._lastPlaceholderInsertion = null;
-    }
-  },
-
-  _getNextPos: function(aNode, aShiftDown, aSize) {
-    // Shifting down is easy:
-    if (this._inPanel && aShiftDown) {
-      return "translate(0, " + aSize.height + "px)";
-    }
-    return this._diffWithNext(aNode, aSize);
-  },
-
-  _diffWithNext: function(aNode, aSize) {
-    let xDiff;
-    let yDiff = null;
-    let nodeBounds = this._lazyStoreGet(aNode);
-    let side = this._dir == "ltr" ? "left" : "right";
-    let next = this._getVisibleSiblingForDirection(aNode, "next");
-    // First we determine the transform along the x axis.
-    // Usually, there will be a next node to base this on:
-    if (next) {
-      let otherBounds = this._lazyStoreGet(next);
-      xDiff = otherBounds[side] - nodeBounds[side];
-      // If the next node is a wide item in the panel, check if we could maybe
-      // just move further out in the same row, without snapping to the next
-      // one. This happens, for example, if moving an item that's before a wide
-      // node within its own row of items. There will be space to drop this
-      // item within the row, and the rest of the items do not need to shift.
-      if (this.isWide(next)) {
-        let otherXDiff = this._moveNextBasedOnPrevious(aNode, nodeBounds,
-                                                       this._firstInRow(aNode));
-        // If this has the same sign as our original shift, we're still
-        // snapping to the start of the row. In this case, we should move
-        // everything after us a row down, so as not to display two nodes on
-        // top of each other:
-        // (we would be able to get away with checking for equality instead of
-        //  equal signs here, but one of these is based on the x coordinate of
-        //  the first item in row N and one on that for row N - 1, so this is
-        //  safer, as their margins might differ)
-        if ((otherXDiff < 0) == (xDiff < 0)) {
-          this.__moveDown = true;
-        } else {
-          // Otherwise, we succeeded and can move further out. This also means
-          // we can stop shifting the rest of the content:
-          xDiff = otherXDiff;
-          this.__undoShift = true;
-        }
-      } else {
-        // We set this explicitly because otherwise some strange difference
-        // between the height and the actual difference between line creeps in
-        // and messes with alignments
-        yDiff = otherBounds.top - nodeBounds.top;
-      }
-    } else {
-      // We don't have a sibling whose position we can use. First, let's see
-      // if we're also the first item (which complicates things):
-      let firstNode = this._firstInRow(aNode);
-      if (aNode == firstNode) {
-        // Maybe we stored the horizontal distance between non-wide nodes,
-        // if not, we'll use the width of the incoming node as a proxy:
-        xDiff = this._horizontalDistance || aSize.width;
-      } else {
-        // If not, we should be able to get the distance to the previous node
-        // and use the inverse, unless there's no room for another node (ie we
-        // are the last node and there's no room for another one)
-        xDiff = this._moveNextBasedOnPrevious(aNode, nodeBounds, firstNode);
-      }
-    }
-
-    // If we've not determined the vertical difference yet, check it here
-    if (yDiff === null) {
-      // If the next node is behind rather than in front, we must have moved
-      // vertically:
-      if ((xDiff > 0 && this._dir == "rtl") || (xDiff < 0 && this._dir == "ltr")) {
-        yDiff = aSize.height;
-      } else {
-        // Otherwise, we haven't
-        yDiff = 0;
-      }
-    }
-    return "translate(" + xDiff + "px, " + yDiff + "px)";
-  },
-
-  /**
-   * Helper function to find the transform a node if there isn't a next node
-   * to base that on.
-   * @param aNode           the node to transform
-   * @param aNodeBounds     the bounding rect info of this node
-   * @param aFirstNodeInRow the first node in aNode's row
-   */
-  _moveNextBasedOnPrevious: function(aNode, aNodeBounds, aFirstNodeInRow) {
-    let next = this._getVisibleSiblingForDirection(aNode, "previous");
-    let otherBounds = this._lazyStoreGet(next);
-    let side = this._dir == "ltr" ? "left" : "right";
-    let xDiff = aNodeBounds[side] - otherBounds[side];
-    // If, however, this means we move outside the container's box
-    // (i.e. the row in which this item is placed is full)
-    // we should move it to align with the first item in the next row instead
-    let bound = this._containerInfo[this._dir == "ltr" ? "right" : "left"];
-    if ((this._dir == "ltr" && xDiff + aNodeBounds.right > bound) ||
-        (this._dir == "rtl" && xDiff + aNodeBounds.left < bound)) {
-      xDiff = this._lazyStoreGet(aFirstNodeInRow)[side] - aNodeBounds[side];
-    }
-    return xDiff;
-  },
-
-  /**
-   * Get position details from our cache. If the node is not yet cached, get its position
-   * information and cache it now.
-   * @param aNode  the node whose position info we want
-   * @return the position info
-   */
-  _lazyStoreGet: function(aNode) {
-    let rect = this._nodePositionStore.get(aNode);
-    if (!rect) {
-      // getBoundingClientRect() returns a DOMRect that is live, meaning that
-      // as the element moves around, the rects values change. We don't want
-      // that - we want a snapshot of what the rect values are right at this
-      // moment, and nothing else. So we have to clone the values.
-      let clientRect = aNode.getBoundingClientRect();
-      rect = {
-        left: clientRect.left,
-        right: clientRect.right,
-        width: clientRect.width,
-        height: clientRect.height,
-        top: clientRect.top,
-        bottom: clientRect.bottom,
-      };
-      rect.x = rect.left + rect.width / 2;
-      rect.y = rect.top + rect.height / 2;
-      Object.freeze(rect);
-      this._nodePositionStore.set(aNode, rect);
-    }
-    return rect;
-  },
-
-  _firstInRow: function(aNode) {
-    // XXXmconley: I'm not entirely sure why we need to take the floor of these
-    // values - it looks like, periodically, we're getting fractional pixels back
-    // from lazyStoreGet. I've filed bug 994247 to investigate.
-    let bound = Math.floor(this._lazyStoreGet(aNode).top);
-    let rv = aNode;
-    let prev;
-    while (rv && (prev = this._getVisibleSiblingForDirection(rv, "previous"))) {
-      if (Math.floor(this._lazyStoreGet(prev).bottom) <= bound) {
-        return rv;
-      }
-      rv = prev;
-    }
-    return rv;
-  },
-
-  _getVisibleSiblingForDirection: function(aNode, aDirection) {
-    let rv = aNode;
-    do {
-      rv = rv[aDirection + "Sibling"];
-    } while (rv && rv.getAttribute("hidden") == "true")
-    return rv;
-  }
-}
-
-var DragPositionManager = {
-  start: function(aWindow) {
-    let areas = CustomizableUI.areas.filter((area) => CustomizableUI.getAreaType(area) != "toolbar");
-    areas = areas.map((area) => CustomizableUI.getCustomizeTargetForArea(area, aWindow));
-    areas.push(aWindow.document.getElementById(kPaletteId));
-    for (let areaNode of areas) {
-      let positionManager = gManagers.get(areaNode);
-      if (positionManager) {
-        positionManager.update(areaNode);
-      } else {
-        gManagers.set(areaNode, new AreaPositionManager(areaNode));
-      }
-    }
-  },
-
-  add: function(aWindow, aArea, aContainer) {
-    if (CustomizableUI.getAreaType(aArea) != "toolbar") {
-      return;
-    }
-
-    gManagers.set(aContainer, new AreaPositionManager(aContainer));
-  },
-
-  remove: function(aWindow, aArea, aContainer) {
-    if (CustomizableUI.getAreaType(aArea) != "toolbar") {
-      return;
-    }
-
-    gManagers.delete(aContainer);
-  },
-
-  stop: function() {
-    gManagers = new WeakMap();
-  },
-
-  getManagerForArea: function(aArea) {
-    return gManagers.get(aArea);
-  }
-};
-
-Object.freeze(DragPositionManager);
diff --git a/browser/components/customizableui/PanelWideWidgetTracker.jsm b/browser/components/customizableui/PanelWideWidgetTracker.jsm
deleted file mode 100644
index 768cebbca..000000000
--- a/browser/components/customizableui/PanelWideWidgetTracker.jsm
+++ /dev/null
@@ -1,172 +0,0 @@
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-"use strict";
-const {classes: Cc, interfaces: Ci, utils: Cu, results: Cr} = Components;
-
-this.EXPORTED_SYMBOLS = ["PanelWideWidgetTracker"];
-
-Cu.import("resource://gre/modules/XPCOMUtils.jsm");
-XPCOMUtils.defineLazyModuleGetter(this, "CustomizableUI",
-  "resource:///modules/CustomizableUI.jsm");
-
-var gPanel = CustomizableUI.AREA_PANEL;
-// We keep track of the widget placements for the panel locally:
-var gPanelPlacements = [];
-
-// All the wide widgets we know of:
-var gWideWidgets = new Set();
-// All the widgets we know of:
-var gSeenWidgets = new Set();
-
-var PanelWideWidgetTracker = {
-  // Listeners used to validate panel contents whenever they change:
-  onWidgetAdded: function(aWidgetId, aArea, aPosition) {
-    if (aArea == gPanel) {
-      gPanelPlacements = CustomizableUI.getWidgetIdsInArea(gPanel);
-      let moveForward = this.shouldMoveForward(aWidgetId, aPosition);
-      this.adjustWidgets(aWidgetId, moveForward);
-    }
-  },
-  onWidgetMoved: function(aWidgetId, aArea, aOldPosition, aNewPosition) {
-    if (aArea == gPanel) {
-      gPanelPlacements = CustomizableUI.getWidgetIdsInArea(gPanel);
-      let moveForward = this.shouldMoveForward(aWidgetId, aNewPosition);
-      this.adjustWidgets(aWidgetId, moveForward);
-    }
-  },
-  onWidgetRemoved: function(aWidgetId, aPrevArea) {
-    if (aPrevArea == gPanel) {
-      gPanelPlacements = CustomizableUI.getWidgetIdsInArea(gPanel);
-      this.adjustWidgets(aWidgetId, false);
-    }
-  },
-  onWidgetReset: function(aWidgetId) {
-    gPanelPlacements = CustomizableUI.getWidgetIdsInArea(gPanel);
-  },
-  // Listener to keep abreast of any new nodes. We use the DOM one because
-  // we need access to the actual node's classlist, so we can't use the ones above.
-  // Furthermore, onWidgetCreated only fires for API-based widgets, not for XUL ones.
-  onWidgetAfterDOMChange: function(aNode, aNextNode, aContainer) {
-    if (!gSeenWidgets.has(aNode.id)) {
-      if (aNode.classList.contains(CustomizableUI.WIDE_PANEL_CLASS)) {
-        gWideWidgets.add(aNode.id);
-      }
-      gSeenWidgets.add(aNode.id);
-    }
-  },
-  // When widgets get destroyed, we remove them from our sets of stuff we care about:
-  onWidgetDestroyed: function(aWidgetId) {
-    gSeenWidgets.delete(aWidgetId);
-    gWideWidgets.delete(aWidgetId);
-  },
-  shouldMoveForward: function(aWidgetId, aPosition) {
-    let currentWidgetAtPosition = gPanelPlacements[aPosition + 1];
-    let rv = gWideWidgets.has(currentWidgetAtPosition) && !gWideWidgets.has(aWidgetId);
-    // We might now think we can move forward, but for that we need at least 2 more small
-    // widgets to be present:
-    if (rv) {
-      let furtherWidgets = gPanelPlacements.slice(aPosition + 2);
-      let realWidgets = 0;
-      if (furtherWidgets.length >= 2) {
-        while (furtherWidgets.length && realWidgets < 2) {
-          let w = furtherWidgets.shift();
-          if (!gWideWidgets.has(w) && this.checkWidgetStatus(w)) {
-            realWidgets++;
-          }
-        }
-      }
-      if (realWidgets < 2) {
-        rv = false;
-      }
-    }
-    return rv;
-  },
-  adjustWidgets: function(aWidgetId, aMoveForwards) {
-    if (this.adjusting) {
-      return;
-    }
-    this.adjusting = true;
-    let widgetsAffected = gPanelPlacements.filter((w) => gWideWidgets.has(w));
-    // If we're moving the wide widgets forwards (down/to the right in the panel)
-    // we want to start with the last widgets. Otherwise we move widgets over other wide
-    // widgets, which might mess up their order. Likewise, if moving backwards we should start with
-    // the first widget and work our way down/right from there.
-    let compareFn = aMoveForwards ? ((a, b) => a < b) : ((a, b) => a > b);
-    widgetsAffected.sort((a, b) => compareFn(gPanelPlacements.indexOf(a),
-                                             gPanelPlacements.indexOf(b)));
-    for (let widget of widgetsAffected) {
-      this.adjustPosition(widget, aMoveForwards);
-    }
-    this.adjusting = false;
-  },
-  // This function is called whenever an item gets moved in the menu panel. It
-  // adjusts the position of widgets within the panel to prevent "gaps" between
-  // wide widgets that could be filled up with single column widgets
-  adjustPosition: function(aWidgetId, aMoveForwards) {
-    // Make sure that there are n % columns = 0 narrow buttons before the widget.
-    let placementIndex = gPanelPlacements.indexOf(aWidgetId);
-    let prevSiblingCount = 0;
-    let fixedPos = null;
-    while (placementIndex--) {
-      let thisWidgetId = gPanelPlacements[placementIndex];
-      if (gWideWidgets.has(thisWidgetId)) {
-        continue;
-      }
-      let widgetStatus = this.checkWidgetStatus(thisWidgetId);
-      if (!widgetStatus) {
-        continue;
-      }
-      if (widgetStatus == "public-only") {
-        fixedPos = !fixedPos ? placementIndex : Math.min(fixedPos, placementIndex);
-        prevSiblingCount = 0;
-      } else {
-        prevSiblingCount++;
-      }
-    }
-
-    if (fixedPos !== null || prevSiblingCount % CustomizableUI.PANEL_COLUMN_COUNT) {
-      let desiredPos = (fixedPos !== null) ? fixedPos : gPanelPlacements.indexOf(aWidgetId);
-      let desiredChange = -(prevSiblingCount % CustomizableUI.PANEL_COLUMN_COUNT);
-      if (aMoveForwards && fixedPos == null) {
-        // +1 because otherwise we'd count ourselves:
-        desiredChange = CustomizableUI.PANEL_COLUMN_COUNT + desiredChange + 1;
-      }
-      desiredPos += desiredChange;
-      CustomizableUI.moveWidgetWithinArea(aWidgetId, desiredPos);
-    }
-  },
-
-  /*
-   * Check whether a widget id is actually known anywhere.
-   * @returns false if the widget doesn't exist,
-   *          "public-only" if it's not shown in private windows
-   *          "real" if it does exist and is shown even in private windows
-   */
-  checkWidgetStatus: function(aWidgetId) {
-    let widgetWrapper = CustomizableUI.getWidget(aWidgetId);
-    // This widget might not actually exist:
-    if (!widgetWrapper) {
-      return false;
-    }
-    // This widget might still not actually exist:
-    if (widgetWrapper.provider == CustomizableUI.PROVIDER_XUL &&
-        widgetWrapper.instances.length == 0) {
-      return false;
-    }
-
-    // Or it might only be there some of the time:
-    if (widgetWrapper.provider == CustomizableUI.PROVIDER_API &&
-        widgetWrapper.showInPrivateBrowsing === false) {
-      return "public-only";
-    }
-    return "real";
-  },
-
-  init: function() {
-    // Initialize our local placements copy and register the listener
-    gPanelPlacements = CustomizableUI.getWidgetIdsInArea(gPanel);
-    CustomizableUI.addListener(this);
-  },
-};
diff --git a/browser/components/customizableui/ScrollbarSampler.jsm b/browser/components/customizableui/ScrollbarSampler.jsm
deleted file mode 100644
index 44736e4c4..000000000
--- a/browser/components/customizableui/ScrollbarSampler.jsm
+++ /dev/null
@@ -1,65 +0,0 @@
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-"use strict";
-
-this.EXPORTED_SYMBOLS = ["ScrollbarSampler"];
-
-const {classes: Cc, interfaces: Ci, utils: Cu, results: Cr} = Components;
-
-Cu.import("resource://gre/modules/Services.jsm");
-Cu.import("resource://gre/modules/XPCOMUtils.jsm");
-
-var gSystemScrollbarWidth = null;
-
-this.ScrollbarSampler = {
-  getSystemScrollbarWidth: function() {
-    if (gSystemScrollbarWidth !== null) {
-      return Promise.resolve(gSystemScrollbarWidth);
-    }
-
-    return new Promise(resolve => {
-      this._sampleSystemScrollbarWidth().then(function(systemScrollbarWidth) {
-        gSystemScrollbarWidth = systemScrollbarWidth;
-        resolve(gSystemScrollbarWidth);
-      });
-    });
-  },
-
-  resetSystemScrollbarWidth: function() {
-    gSystemScrollbarWidth = null;
-  },
-
-  _sampleSystemScrollbarWidth: function() {
-    let hwin = Services.appShell.hiddenDOMWindow;
-    let hdoc = hwin.document.documentElement;
-    let iframe = hwin.document.createElementNS("http://www.w3.org/1999/xhtml",
-                                               "html:iframe");
-    iframe.setAttribute("srcdoc", '<body style="overflow-y: scroll"></body>');
-    hdoc.appendChild(iframe);
-
-    let cwindow = iframe.contentWindow;
-    let utils = cwindow.QueryInterface(Ci.nsIInterfaceRequestor)
-                       .getInterface(Ci.nsIDOMWindowUtils);
-
-    return new Promise(resolve => {
-      cwindow.addEventListener("load", function onLoad(aEvent) {
-        cwindow.removeEventListener("load", onLoad);
-        let sbWidth = {};
-        try {
-          utils.getScrollbarSize(true, sbWidth, {});
-        } catch (e) {
-          Cu.reportError("Could not sample scrollbar size: " + e + " -- " +
-                         e.stack);
-          sbWidth.value = 0;
-        }
-        // Minimum width of 10 so that we have enough padding:
-        sbWidth.value = Math.max(sbWidth.value, 10);
-        resolve(sbWidth.value);
-        iframe.remove();
-      });
-    });
-  }
-};
-Object.freeze(this.ScrollbarSampler);
diff --git a/browser/components/customizableui/content/customizeMode.inc.xul b/browser/components/customizableui/content/customizeMode.inc.xul
deleted file mode 100644
index b665630a2..000000000
--- a/browser/components/customizableui/content/customizeMode.inc.xul
+++ /dev/null
@@ -1,82 +0,0 @@
-<!-- This Source Code Form is subject to the terms of the Mozilla Public
-   - License, v. 2.0. If a copy of the MPL was not distributed with this
-   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
-
-<hbox id="customization-container" flex="1" hidden="true">
-  <vbox flex="1" id="customization-palette-container">
-    <label id="customization-header">
-      &customizeMode.menuAndToolbars.header2;
-    </label>
-    <hbox id="customization-empty" hidden="true">
-      <label>&customizeMode.menuAndToolbars.empty;</label>
-      <label onclick="BrowserOpenAddonsMgr('addons://discover/');"
-             onkeypress="BrowserOpenAddonsMgr('addons://discover/');"
-             id="customization-more-tools"
-             class="text-link">
-        &customizeMode.menuAndToolbars.emptyLink;
-      </label>
-    </hbox>
-    <vbox id="customization-palette" class="customization-palette"/>
-    <spacer id="customization-spacer"/>
-    <hbox id="customization-footer">
-#ifdef CAN_DRAW_IN_TITLEBAR
-      <button id="customization-titlebar-visibility-button" class="customizationmode-button"
-              label="&customizeMode.titlebar;" type="checkbox"
-#NB: because oncommand fires after click, by the time we've fired, the checkbox binding
-#    will already have switched the button's state, so this is correct:
-              oncommand="gCustomizeMode.toggleTitlebar(this.hasAttribute('checked'))"/>
-#endif
-      <button id="customization-toolbar-visibility-button" label="&customizeMode.toolbars;" class="customizationmode-button" type="menu">
-        <menupopup id="customization-toolbar-menu" onpopupshowing="onViewToolbarsPopupShowing(event)"/>
-      </button>
-      <button id="customization-lwtheme-button" label="&customizeMode.lwthemes;" class="customizationmode-button" type="menu">
-        <panel type="arrow" id="customization-lwtheme-menu"
-               onpopupshowing="gCustomizeMode.onLWThemesMenuShowing(event);"
-               position="topcenter bottomleft"
-               flip="none"
-               role="menu">
-          <label id="customization-lwtheme-menu-header" value="&customizeMode.lwthemes.myThemes;"/>
-          <label id="customization-lwtheme-menu-recommended" value="&customizeMode.lwthemes.recommended;"/>
-          <hbox id="customization-lwtheme-menu-footer">
-            <toolbarbutton class="customization-lwtheme-menu-footeritem"
-                           label="&customizeMode.lwthemes.menuManage;"
-                           accesskey="&customizeMode.lwthemes.menuManage.accessKey;"
-                           tabindex="0"
-                           oncommand="gCustomizeMode.openAddonsManagerThemes(event);"/>
-            <toolbarbutton class="customization-lwtheme-menu-footeritem"
-                           label="&customizeMode.lwthemes.menuGetMore;"
-                           accesskey="&customizeMode.lwthemes.menuGetMore.accessKey;"
-                           tabindex="0"
-                           oncommand="gCustomizeMode.getMoreThemes(event);"/>
-          </hbox>
-        </panel>
-      </button>
-
-      <spacer id="customization-footer-spacer"/>
-      <button id="customization-undo-reset-button"
-              class="customizationmode-button"
-              hidden="true"
-              oncommand="gCustomizeMode.undoReset();"
-              label="&undoCmd.label;"/>
-      <button id="customization-reset-button"
-              oncommand="gCustomizeMode.reset();"
-              label="&customizeMode.restoreDefaults;"
-              class="customizationmode-button"/>
-    </hbox>
-  </vbox>
-  <vbox id="customization-panel-container">
-    <vbox id="customization-panelWrapper">
-      <html:style html:type="text/html" scoped="scoped">
-        @import url(chrome://global/skin/popup.css);
-      </html:style>
-      <box class="panel-arrowbox">
-        <box flex="1"/>
-        <image class="panel-arrow" side="top"/>
-      </box>
-      <box class="panel-arrowcontent" side="top" flex="1">
-        <hbox id="customization-panelHolder"/>
-        <box class="panel-inner-arrowcontentfooter" hidden="true"/>
-      </box>
-    </vbox>
-  </vbox>
-</hbox>
diff --git a/browser/components/customizableui/content/jar.mn b/browser/components/customizableui/content/jar.mn
deleted file mode 100644
index 05c0112cd..000000000
--- a/browser/components/customizableui/content/jar.mn
+++ /dev/null
@@ -1,10 +0,0 @@
-# This Source Code Form is subject to the terms of the Mozilla Public
-# License, v. 2.0. If a copy of the MPL was not distributed with this
-# file, You can obtain one at http://mozilla.org/MPL/2.0/.
-
-browser.jar:
-  content/browser/customizableui/panelUI.css
-  content/browser/customizableui/panelUI.js
-  content/browser/customizableui/panelUI.xml
-  content/browser/customizableui/toolbar.xml
-
diff --git a/browser/components/customizableui/content/moz.build b/browser/components/customizableui/content/moz.build
deleted file mode 100644
index eb4454d28..000000000
--- a/browser/components/customizableui/content/moz.build
+++ /dev/null
@@ -1,7 +0,0 @@
-# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
-# vim: set filetype=python:
-# 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/.
-
-JAR_MANIFESTS += ['jar.mn']
\ No newline at end of file
diff --git a/browser/components/customizableui/content/panelUI.css b/browser/components/customizableui/content/panelUI.css
deleted file mode 100644
index ba44636f1..000000000
--- a/browser/components/customizableui/content/panelUI.css
+++ /dev/null
@@ -1,31 +0,0 @@
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-.panel-viewstack[viewtype="main"] > .panel-clickcapturer {
-  pointer-events: none;
-}
-
-.panel-mainview,
-.panel-viewcontainer,
-.panel-viewstack {
-  overflow: hidden;
-}
-
-.panel-viewstack {
-  position: relative;
-}
-
-.panel-subviews {
-  -moz-stack-sizing: ignore;
-  transform: translateX(0);
-  overflow-y: auto;
-}
-
-.panel-subviews[panelopen] {
-  transition: transform var(--panelui-subview-transition-duration);
-}
-
-.panel-viewcontainer[panelopen]:-moz-any(:not([viewtype="main"]),[transitioning="true"]) {
-  transition: height var(--panelui-subview-transition-duration);
-}
diff --git a/browser/components/customizableui/content/panelUI.inc.xul b/browser/components/customizableui/content/panelUI.inc.xul
deleted file mode 100644
index e389b14bf..000000000
--- a/browser/components/customizableui/content/panelUI.inc.xul
+++ /dev/null
@@ -1,386 +0,0 @@
-<!-- This Source Code Form is subject to the terms of the Mozilla Public
-   - License, v. 2.0. If a copy of the MPL was not distributed with this
-   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
-
-<panel id="PanelUI-popup"
-       role="group"
-       type="arrow"
-       hidden="true"
-       flip="slide"
-       position="bottomcenter topright"
-       noautofocus="true">
-  <panelmultiview id="PanelUI-multiView" mainViewId="PanelUI-mainView">
-    <panelview id="PanelUI-mainView" context="customizationPanelContextMenu">
-      <vbox id="PanelUI-contents-scroller">
-        <vbox id="PanelUI-contents" class="panelUI-grid"/>
-      </vbox>
-
-      <footer id="PanelUI-footer">
-        <toolbarbutton id="PanelUI-update-status"
-                       oncommand="gMenuButtonUpdateBadge.onMenuPanelCommand(event);"
-                       wrap="true"
-                       hidden="true"/>
-        <hbox id="PanelUI-footer-fxa">
-          <hbox id="PanelUI-fxa-status"
-                defaultlabel="&fxaSignIn.label;"
-                signedinTooltiptext="&fxaSignedIn.tooltip;"
-                tooltiptext="&fxaSignedIn.tooltip;"
-                errorlabel="&fxaSignInError.label;"
-                unverifiedlabel="&fxaUnverified.label;"
-                onclick="if (event.which == 1) gFxAccounts.onMenuPanelCommand();">
-            <image id="PanelUI-fxa-avatar"/>
-            <toolbarbutton id="PanelUI-fxa-label"
-                           fxabrandname="&syncBrand.fxAccount.label;"/>
-          </hbox>
-          <toolbarseparator/>
-          <toolbarbutton id="PanelUI-fxa-icon"
-                         oncommand="gSyncUI.doSync();"
-                         closemenu="none">
-            <observes element="sync-status" attribute="syncstatus"/>
-            <observes element="sync-status" attribute="tooltiptext"/>
-          </toolbarbutton>
-        </hbox>
-
-        <hbox id="PanelUI-footer-inner">
-          <toolbarbutton id="PanelUI-customize" label="&appMenuCustomize.label;"
-                         exitLabel="&appMenuCustomizeExit.label;"
-                         tooltiptext="&appMenuCustomize.tooltip;"
-                         exitTooltiptext="&appMenuCustomizeExit.tooltip;"
-                         closemenu="none"
-                         oncommand="gCustomizeMode.toggle();"/>
-          <toolbarseparator/>
-          <toolbarbutton id="PanelUI-help" label="&helpMenu.label;"
-                         closemenu="none"
-                         tooltiptext="&appMenuHelp.tooltip;"
-                         oncommand="PanelUI.showHelpView(this);"/>
-          <toolbarseparator/>
-          <toolbarbutton id="PanelUI-quit"
-#ifdef XP_WIN
-                         label="&quitApplicationCmdWin2.label;"
-                         tooltiptext="&quitApplicationCmdWin2.tooltip;"
-#else
-#ifdef XP_MACOSX
-                         label="&quitApplicationCmdMac2.label;"
-#else
-                         label="&quitApplicationCmd.label;"
-#endif
-#endif
-                         command="cmd_quitApplication"/>
-        </hbox>
-      </footer>
-    </panelview>
-
-    <panelview id="PanelUI-history" flex="1">
-      <label value="&appMenuHistory.label;" class="panel-subview-header"/>
-      <vbox class="panel-subview-body">
-        <toolbarbutton id="appMenuViewHistorySidebar"
-                       label="&appMenuHistory.viewSidebar.label;"
-                       type="checkbox"
-                       class="subviewbutton"
-                       key="key_gotoHistory"
-                       oncommand="SidebarUI.toggle('viewHistorySidebar'); PanelUI.hide();">
-          <observes element="viewHistorySidebar" attribute="checked"/>
-        </toolbarbutton>
-        <toolbarbutton id="appMenuClearRecentHistory"
-                       label="&appMenuHistory.clearRecent.label;"
-                       class="subviewbutton"
-                       command="Tools:Sanitize"/>
-        <toolbarbutton id="appMenuRestoreLastSession"
-                       label="&appMenuHistory.restoreSession.label;"
-                       class="subviewbutton"
-                       command="Browser:RestoreLastSession"/>
-        <menuseparator id="PanelUI-recentlyClosedTabs-separator"/>
-        <vbox id="PanelUI-recentlyClosedTabs" tooltip="bhTooltip"/>
-        <menuseparator id="PanelUI-recentlyClosedWindows-separator"/>
-        <vbox id="PanelUI-recentlyClosedWindows" tooltip="bhTooltip"/>
-        <menuseparator id="PanelUI-historyItems-separator"/>
-        <vbox id="PanelUI-historyItems" tooltip="bhTooltip"/>
-      </vbox>
-      <toolbarbutton id="PanelUI-historyMore"
-                     class="panel-subview-footer subviewbutton"
-                     label="&appMenuHistory.showAll.label;"
-                     oncommand="PlacesCommandHook.showPlacesOrganizer('History'); CustomizableUI.hidePanelForNode(this);"/>
-    </panelview>
-
-    <panelview id="PanelUI-remotetabs" flex="1" class="PanelUI-subView">
-      <label value="&appMenuRemoteTabs.label;" class="panel-subview-header"/>
-      <vbox class="panel-subview-body">
-        <!-- this widget has 3 boxes in the body, but only 1 is ever visible -->
-        <!-- When Sync is ready to sync -->
-        <vbox id="PanelUI-remotetabs-main" observes="sync-syncnow-state">
-          <vbox id="PanelUI-remotetabs-buttons">
-            <toolbarbutton id="PanelUI-remotetabs-view-sidebar"
-                           class="subviewbutton"
-                           observes="viewTabsSidebar"
-                           label="&appMenuRemoteTabs.sidebar.label;"/>
-            <toolbarbutton id="PanelUI-remotetabs-syncnow"
-                           observes="sync-status"
-                           class="subviewbutton"
-                           oncommand="gSyncUI.doSync();"
-                           closemenu="none"/>
-            <menuseparator id="PanelUI-remotetabs-separator"/>
-          </vbox>
-          <deck id="PanelUI-remotetabs-deck">
-            <!-- Sync is ready to Sync and the "tabs" engine is enabled -->
-            <vbox id="PanelUI-remotetabs-tabspane">
-              <vbox id="PanelUI-remotetabs-tabslist"
-                    notabsforclientlabel="&appMenuRemoteTabs.notabs.label;"
-                    />
-            </vbox>
-            <!-- Sync is ready to Sync but the "tabs" engine isn't enabled-->
-            <hbox id="PanelUI-remotetabs-tabsdisabledpane" pack="center" flex="1">
-              <vbox class="PanelUI-remotetabs-instruction-box">
-                <hbox pack="center">
-                  <image class="fxaSyncIllustration" alt=""/>
-                </hbox>
-                <label class="PanelUI-remotetabs-instruction-label">&appMenuRemoteTabs.tabsnotsyncing.label;</label>
-                <hbox pack="center">
-                  <toolbarbutton class="PanelUI-remotetabs-prefs-button"
-                                 label="&appMenuRemoteTabs.openprefs.label;"
-                                 oncommand="gSyncUI.openSetup(null, 'synced-tabs');"/>
-                </hbox>
-              </vbox>
-            </hbox>
-            <!-- Sync is ready to Sync but we are still fetching the tabs to show -->
-            <vbox id="PanelUI-remotetabs-fetching">
-              <!-- Show intentionally blank panel, see bug 1239845 -->
-            </vbox>
-            <!-- Sync has only 1 (ie, this) device connected -->
-            <hbox id="PanelUI-remotetabs-nodevicespane" pack="center" flex="1">
-              <vbox class="PanelUI-remotetabs-instruction-box">
-                <hbox pack="center">
-                  <image class="fxaSyncIllustration" alt=""/>
-                </hbox>
-                <label class="PanelUI-remotetabs-instruction-title">&appMenuRemoteTabs.noclients.title;</label>
-                <label class="PanelUI-remotetabs-instruction-label">&appMenuRemoteTabs.noclients.subtitle;</label>
-                <!-- The inner HTML for PanelUI-remotetabs-mobile-promo is built at runtime -->
-                <label id="PanelUI-remotetabs-mobile-promo" fxAccountsBrand="&syncBrand.fxAccount.label;"/>
-              </vbox>
-            </hbox>
-          </deck>
-        </vbox>
-        <!-- a box to ensure contained boxes are centered horizonally -->
-        <hbox pack="center" flex="1">
-          <!-- When Sync is not configured -->
-          <vbox id="PanelUI-remotetabs-setupsync"
-                flex="1"
-                align="center"
-                class="PanelUI-remotetabs-instruction-box"
-                observes="sync-setup-state">
-            <image class="fxaSyncIllustration" alt=""/>
-            <label class="PanelUI-remotetabs-instruction-label">&appMenuRemoteTabs.notsignedin.label;</label>
-            <toolbarbutton class="PanelUI-remotetabs-prefs-button"
-                           label="&appMenuRemoteTabs.signin.label;"
-                           oncommand="gSyncUI.openSetup(null, 'synced-tabs');"/>
-          </vbox>
-          <!-- When Sync needs re-authentication. This uses the exact same messaging
-               as "Sync is not configured" but remains a separate box so we get
-               the goodness of observing broadcasters to manage the hidden states -->
-          <vbox id="PanelUI-remotetabs-reauthsync"
-                flex="1"
-                align="center"
-                class="PanelUI-remotetabs-instruction-box"
-                observes="sync-reauth-state">
-            <image class="fxaSyncIllustration" alt=""/>
-            <label class="PanelUI-remotetabs-instruction-label">&appMenuRemoteTabs.notsignedin.label;</label>
-            <toolbarbutton class="PanelUI-remotetabs-prefs-button"
-                           label="&appMenuRemoteTabs.signin.label;"
-                           oncommand="gSyncUI.openSetup(null, 'synced-tabs');"/>
-          </vbox>
-        </hbox>
-      </vbox>
-    </panelview>
-
-    <panelview id="PanelUI-bookmarks" flex="1" class="PanelUI-subView">
-      <label value="&bookmarksMenu.label;" class="panel-subview-header"/>
-      <vbox class="panel-subview-body">
-        <toolbarbutton id="panelMenuBookmarkThisPage"
-                       class="subviewbutton"
-                       observes="bookmarkThisPageBroadcaster"
-                       command="Browser:AddBookmarkAs"
-                       onclick="PanelUI.hide();"/>
-        <toolbarseparator/>
-        <toolbarbutton id="panelMenu_viewBookmarksSidebar"
-                       label="&viewBookmarksSidebar2.label;"
-                       class="subviewbutton"
-                       key="viewBookmarksSidebarKb"
-                       oncommand="SidebarUI.toggle('viewBookmarksSidebar'); PanelUI.hide();">
-          <observes element="viewBookmarksSidebar" attribute="checked"/>
-        </toolbarbutton>
-        <toolbarbutton id="panelMenu_viewBookmarksToolbar"
-                       label="&viewBookmarksToolbar.label;"
-                       type="checkbox"
-                       toolbarId="PersonalToolbar"
-                       class="subviewbutton"
-                       oncommand="onViewToolbarCommand(event); PanelUI.hide();"/>
-        <toolbarseparator/>
-        <toolbarbutton id="panelMenu_bookmarksToolbar"
-                       label="&personalbarCmd.label;"
-                       class="subviewbutton cui-withicon"
-                       oncommand="PlacesCommandHook.showPlacesOrganizer('BookmarksToolbar'); PanelUI.hide();"/>
-        <toolbarbutton id="panelMenu_unsortedBookmarks"
-                       label="&otherBookmarksCmd.label;"
-                       class="subviewbutton cui-withicon"
-                       oncommand="PlacesCommandHook.showPlacesOrganizer('UnfiledBookmarks'); PanelUI.hide();"/>
-        <toolbarseparator class="small-separator"/>
-        <toolbaritem id="panelMenu_bookmarksMenu"
-                     orient="vertical"
-                     smoothscroll="false"
-                     onclick="if (event.button == 1) BookmarkingUI.onPanelMenuViewCommand(event, this._placesView);"
-                     oncommand="BookmarkingUI.onPanelMenuViewCommand(event, this._placesView);"
-                     flatList="true"
-                     tooltip="bhTooltip">
-          <!-- bookmarks menu items will go here -->
-        </toolbaritem>
-      </vbox>
-      <toolbarbutton id="panelMenu_showAllBookmarks"
-                     label="&showAllBookmarks2.label;"
-                     class="subviewbutton panel-subview-footer"
-                     command="Browser:ShowAllBookmarks"
-                     onclick="PanelUI.hide();"/>
-    </panelview>
-
-    <panelview id="PanelUI-feeds" flex="1" oncommand="FeedHandler.subscribeToFeed(null, event);">
-      <label value="&feedsMenu2.label;" class="panel-subview-header"/>
-    </panelview>
-
-    <panelview id="PanelUI-containers" flex="1">
-      <label value="&containersMenu.label;" class="panel-subview-header"/>
-      <vbox id="PanelUI-containersItems"/>
-    </panelview>
-
-    <panelview id="PanelUI-helpView" flex="1" class="PanelUI-subView">
-      <label value="&helpMenu.label;" class="panel-subview-header"/>
-      <vbox id="PanelUI-helpItems" class="panel-subview-body"/>
-    </panelview>
-
-    <panelview id="PanelUI-developer" flex="1">
-      <label value="&webDeveloperMenu.label;" class="panel-subview-header"/>
-      <vbox id="PanelUI-developerItems" class="panel-subview-body"/>
-    </panelview>
-
-    <panelview id="PanelUI-sidebar" flex="1">
-      <label value="&appMenuSidebars.label;" class="panel-subview-header"/>
-      <vbox id="PanelUI-sidebarItems" class="panel-subview-body"/>
-    </panelview>
-
-    <panelview id="PanelUI-characterEncodingView" flex="1">
-      <label value="&charsetMenu2.label;" class="panel-subview-header"/>
-      <vbox class="panel-subview-body">
-        <vbox id="PanelUI-characterEncodingView-pinned"
-              class="PanelUI-characterEncodingView-list"/>
-        <toolbarseparator/>
-        <vbox id="PanelUI-characterEncodingView-charsets"
-              class="PanelUI-characterEncodingView-list"/>
-        <toolbarseparator/>
-        <vbox>
-          <label id="PanelUI-characterEncodingView-autodetect-label"/>
-          <vbox id="PanelUI-characterEncodingView-autodetect"
-                class="PanelUI-characterEncodingView-list"/>
-        </vbox>
-      </vbox>
-    </panelview>
-
-    <panelview id="PanelUI-panicView" flex="1">
-      <vbox class="panel-subview-body">
-        <hbox id="PanelUI-panic-timeframe">
-          <image id="PanelUI-panic-timeframe-icon" alt=""/>
-          <vbox flex="1">
-            <hbox id="PanelUI-panic-header">
-              <image id="PanelUI-panic-timeframe-icon-small" alt=""/>
-              <description id="PanelUI-panic-mainDesc" flex="1">&panicButton.view.mainTimeframeDesc;</description>
-            </hbox>
-            <radiogroup id="PanelUI-panic-timeSpan" aria-labelledby="PanelUI-panic-mainDesc" closemenu="none">
-              <radio id="PanelUI-panic-5min" label="&panicButton.view.5min;" selected="true"
-                     value="5" class="subviewradio"/>
-              <radio id="PanelUI-panic-2hr" label="&panicButton.view.2hr;"
-                     value="2" class="subviewradio"/>
-              <radio id="PanelUI-panic-day" label="&panicButton.view.day;"
-                     value="6" class="subviewradio"/>
-            </radiogroup>
-          </vbox>
-        </hbox>
-        <vbox id="PanelUI-panic-explanations">
-          <label id="PanelUI-panic-actionlist-main-label">&panicButton.view.mainActionDesc;</label>
-
-          <label id="PanelUI-panic-actionlist-windows" class="PanelUI-panic-actionlist">&panicButton.view.deleteTabsAndWindows;</label>
-          <label id="PanelUI-panic-actionlist-cookies" class="PanelUI-panic-actionlist">&panicButton.view.deleteCookies;</label>
-          <label id="PanelUI-panic-actionlist-history" class="PanelUI-panic-actionlist">&panicButton.view.deleteHistory;</label>
-          <label id="PanelUI-panic-actionlist-newwindow" class="PanelUI-panic-actionlist">&panicButton.view.openNewWindow;</label>
-
-          <label id="PanelUI-panic-warning">&panicButton.view.undoWarning;</label>
-        </vbox>
-        <button id="PanelUI-panic-view-button"
-                label="&panicButton.view.forgetButton;"/>
-      </vbox>
-    </panelview>
-
-  </panelmultiview>
-  <!-- These menupopups are located here to prevent flickering,
-       see bug 492960 comment 20. -->
-  <menupopup id="customizationPanelItemContextMenu">
-    <menuitem oncommand="gCustomizeMode.addToToolbar(document.popupNode)"
-              closemenu="single"
-              class="customize-context-moveToToolbar"
-              accesskey="&customizeMenu.moveToToolbar.accesskey;"
-              label="&customizeMenu.moveToToolbar.label;"/>
-    <menuitem oncommand="gCustomizeMode.removeFromArea(document.popupNode)"
-              closemenu="single"
-              class="customize-context-removeFromPanel"
-              accesskey="&customizeMenu.removeFromMenu.accesskey;"
-              label="&customizeMenu.removeFromMenu.label;"/>
-    <menuseparator/>
-    <menuitem command="cmd_CustomizeToolbars"
-              class="viewCustomizeToolbar"
-              accesskey="&viewCustomizeToolbar.accesskey;"
-              label="&viewCustomizeToolbar.label;"/>
-  </menupopup>
-
-  <menupopup id="customizationPaletteItemContextMenu">
-    <menuitem oncommand="gCustomizeMode.addToToolbar(document.popupNode)"
-              class="customize-context-addToToolbar"
-              accesskey="&customizeMenu.addToToolbar.accesskey;"
-              label="&customizeMenu.addToToolbar.label;"/>
-    <menuitem oncommand="gCustomizeMode.addToPanel(document.popupNode)"
-              class="customize-context-addToPanel"
-              accesskey="&customizeMenu.addToPanel.accesskey;"
-              label="&customizeMenu.addToPanel.label;"/>
-  </menupopup>
-
-  <menupopup id="customizationPanelContextMenu">
-    <menuitem command="cmd_CustomizeToolbars"
-              accesskey="&customizeMenu.addMoreItems.accesskey;"
-              label="&customizeMenu.addMoreItems.label;"/>
-  </menupopup>
-</panel>
-
-<panel id="widget-overflow"
-       role="group"
-       type="arrow"
-       noautofocus="true"
-       context="toolbar-context-menu"
-       position="bottomcenter topright"
-       hidden="true">
-  <vbox id="widget-overflow-scroller">
-    <vbox id="widget-overflow-list" class="widget-overflow-list"
-          overflowfortoolbar="nav-bar"/>
-  </vbox>
-</panel>
-
-<panel id="panic-button-success-notification"
-       type="arrow"
-       position="bottomcenter topright"
-       hidden="true"
-       role="alert"
-       orient="vertical">
-  <hbox id="panic-button-success-header">
-    <image id="panic-button-success-icon" alt=""/>
-    <vbox>
-      <description>&panicButton.thankyou.msg1;</description>
-      <description>&panicButton.thankyou.msg2;</description>
-    </vbox>
-  </hbox>
-  <button label="&panicButton.thankyou.buttonlabel;"
-          id="panic-button-success-closebutton"
-          oncommand="PanicButtonNotifier.close()"/>
-</panel>
diff --git a/browser/components/customizableui/content/panelUI.js b/browser/components/customizableui/content/panelUI.js
deleted file mode 100644
index 66fa0c184..000000000
--- a/browser/components/customizableui/content/panelUI.js
+++ /dev/null
@@ -1,558 +0,0 @@
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this file,
- * You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-XPCOMUtils.defineLazyModuleGetter(this, "CustomizableUI",
-                                  "resource:///modules/CustomizableUI.jsm");
-XPCOMUtils.defineLazyModuleGetter(this, "ScrollbarSampler",
-                                  "resource:///modules/ScrollbarSampler.jsm");
-XPCOMUtils.defineLazyModuleGetter(this, "ShortcutUtils",
-                                  "resource://gre/modules/ShortcutUtils.jsm");
-XPCOMUtils.defineLazyModuleGetter(this, "AppConstants",
-                                  "resource://gre/modules/AppConstants.jsm");
-
-/**
- * Maintains the state and dispatches events for the main menu panel.
- */
-
-const PanelUI = {
-  /** Panel events that we listen for. **/
-  get kEvents() {
-    return ["popupshowing", "popupshown", "popuphiding", "popuphidden"];
-  },
-  /**
-   * Used for lazily getting and memoizing elements from the document. Lazy
-   * getters are set in init, and memoizing happens after the first retrieval.
-   */
-  get kElements() {
-    return {
-      contents: "PanelUI-contents",
-      mainView: "PanelUI-mainView",
-      multiView: "PanelUI-multiView",
-      helpView: "PanelUI-helpView",
-      menuButton: "PanelUI-menu-button",
-      panel: "PanelUI-popup",
-      scroller: "PanelUI-contents-scroller"
-    };
-  },
-
-  _initialized: false,
-  init: function() {
-    for (let [k, v] of Object.entries(this.kElements)) {
-      // Need to do fresh let-bindings per iteration
-      let getKey = k;
-      let id = v;
-      this.__defineGetter__(getKey, function() {
-        delete this[getKey];
-        return this[getKey] = document.getElementById(id);
-      });
-    }
-
-    this.menuButton.addEventListener("mousedown", this);
-    this.menuButton.addEventListener("keypress", this);
-    this._overlayScrollListenerBoundFn = this._overlayScrollListener.bind(this);
-    window.matchMedia("(-moz-overlay-scrollbars)").addListener(this._overlayScrollListenerBoundFn);
-    CustomizableUI.addListener(this);
-    this._initialized = true;
-  },
-
-  _eventListenersAdded: false,
-  _ensureEventListenersAdded: function() {
-    if (this._eventListenersAdded)
-      return;
-    this._addEventListeners();
-  },
-
-  _addEventListeners: function() {
-    for (let event of this.kEvents) {
-      this.panel.addEventListener(event, this);
-    }
-
-    this.helpView.addEventListener("ViewShowing", this._onHelpViewShow, false);
-    this._eventListenersAdded = true;
-  },
-
-  uninit: function() {
-    for (let event of this.kEvents) {
-      this.panel.removeEventListener(event, this);
-    }
-    this.helpView.removeEventListener("ViewShowing", this._onHelpViewShow);
-    this.menuButton.removeEventListener("mousedown", this);
-    this.menuButton.removeEventListener("keypress", this);
-    window.matchMedia("(-moz-overlay-scrollbars)").removeListener(this._overlayScrollListenerBoundFn);
-    CustomizableUI.removeListener(this);
-    this._overlayScrollListenerBoundFn = null;
-  },
-
-  /**
-   * Customize mode extracts the mainView and puts it somewhere else while the
-   * user customizes. Upon completion, this function can be called to put the
-   * panel back to where it belongs in normal browsing mode.
-   *
-   * @param aMainView
-   *        The mainView node to put back into place.
-   */
-  setMainView: function(aMainView) {
-    this._ensureEventListenersAdded();
-    this.multiView.setMainView(aMainView);
-  },
-
-  /**
-   * Opens the menu panel if it's closed, or closes it if it's
-   * open.
-   *
-   * @param aEvent the event that triggers the toggle.
-   */
-  toggle: function(aEvent) {
-    // Don't show the panel if the window is in customization mode,
-    // since this button doubles as an exit path for the user in this case.
-    if (document.documentElement.hasAttribute("customizing")) {
-      return;
-    }
-    this._ensureEventListenersAdded();
-    if (this.panel.state == "open") {
-      this.hide();
-    } else if (this.panel.state == "closed") {
-      this.show(aEvent);
-    }
-  },
-
-  /**
-   * Opens the menu panel. If the event target has a child with the
-   * toolbarbutton-icon attribute, the panel will be anchored on that child.
-   * Otherwise, the panel is anchored on the event target itself.
-   *
-   * @param aEvent the event (if any) that triggers showing the menu.
-   */
-  show: function(aEvent) {
-    return new Promise(resolve => {
-      this.ensureReady().then(() => {
-        if (this.panel.state == "open" ||
-            document.documentElement.hasAttribute("customizing")) {
-          resolve();
-          return;
-        }
-
-        let editControlPlacement = CustomizableUI.getPlacementOfWidget("edit-controls");
-        if (editControlPlacement && editControlPlacement.area == CustomizableUI.AREA_PANEL) {
-          updateEditUIVisibility();
-        }
-
-        let personalBookmarksPlacement = CustomizableUI.getPlacementOfWidget("personal-bookmarks");
-        if (personalBookmarksPlacement &&
-            personalBookmarksPlacement.area == CustomizableUI.AREA_PANEL) {
-          PlacesToolbarHelper.customizeChange();
-        }
-
-        let anchor;
-        if (!aEvent ||
-            aEvent.type == "command") {
-          anchor = this.menuButton;
-        } else {
-          anchor = aEvent.target;
-        }
-
-        this.panel.addEventListener("popupshown", function onPopupShown() {
-          this.removeEventListener("popupshown", onPopupShown);
-          resolve();
-        });
-
-        let iconAnchor =
-          document.getAnonymousElementByAttribute(anchor, "class",
-                                                  "toolbarbutton-icon");
-        this.panel.openPopup(iconAnchor || anchor);
-      }, (reason) => {
-        console.error("Error showing the PanelUI menu", reason);
-      });
-    });
-  },
-
-  /**
-   * If the menu panel is being shown, hide it.
-   */
-  hide: function() {
-    if (document.documentElement.hasAttribute("customizing")) {
-      return;
-    }
-
-    this.panel.hidePopup();
-  },
-
-  handleEvent: function(aEvent) {
-    // Ignore context menus and menu button menus showing and hiding:
-    if (aEvent.type.startsWith("popup") &&
-        aEvent.target != this.panel) {
-      return;
-    }
-    switch (aEvent.type) {
-      case "popupshowing":
-        this._adjustLabelsForAutoHyphens();
-        // Fall through
-      case "popupshown":
-        // Fall through
-      case "popuphiding":
-        // Fall through
-      case "popuphidden":
-        this._updatePanelButton(aEvent.target);
-        break;
-      case "mousedown":
-        if (aEvent.button == 0)
-          this.toggle(aEvent);
-        break;
-      case "keypress":
-        this.toggle(aEvent);
-        break;
-    }
-  },
-
-  get isReady() {
-    return !!this._isReady;
-  },
-
-  /**
-   * Registering the menu panel is done lazily for performance reasons. This
-   * method is exposed so that CustomizationMode can force panel-readyness in the
-   * event that customization mode is started before the panel has been opened
-   * by the user.
-   *
-   * @param aCustomizing (optional) set to true if this was called while entering
-   *        customization mode. If that's the case, we trust that customization
-   *        mode will handle calling beginBatchUpdate and endBatchUpdate.
-   *
-   * @return a Promise that resolves once the panel is ready to roll.
-   */
-  ensureReady: function(aCustomizing=false) {
-    if (this._readyPromise) {
-      return this._readyPromise;
-    }
-    this._readyPromise = Task.spawn(function*() {
-      if (!this._initialized) {
-        yield new Promise(resolve => {
-          let delayedStartupObserver = (aSubject, aTopic, aData) => {
-            if (aSubject == window) {
-              Services.obs.removeObserver(delayedStartupObserver, "browser-delayed-startup-finished");
-              resolve();
-            }
-          };
-          Services.obs.addObserver(delayedStartupObserver, "browser-delayed-startup-finished", false);
-        });
-      }
-
-      this.contents.setAttributeNS("http://www.w3.org/XML/1998/namespace", "lang",
-                                   getLocale());
-      if (!this._scrollWidth) {
-        // In order to properly center the contents of the panel, while ensuring
-        // that we have enough space on either side to show a scrollbar, we have to
-        // do a bit of hackery. In particular, we calculate a new width for the
-        // scroller, based on the system scrollbar width.
-        this._scrollWidth =
-          (yield ScrollbarSampler.getSystemScrollbarWidth()) + "px";
-        let cstyle = window.getComputedStyle(this.scroller);
-        let widthStr = cstyle.width;
-        // Get the calculated padding on the left and right sides of
-        // the scroller too. We'll use that in our final calculation so
-        // that if a scrollbar appears, we don't have the contents right
-        // up against the edge of the scroller.
-        let paddingLeft = cstyle.paddingLeft;
-        let paddingRight = cstyle.paddingRight;
-        let calcStr = [widthStr, this._scrollWidth,
-                       paddingLeft, paddingRight].join(" + ");
-        this.scroller.style.width = "calc(" + calcStr + ")";
-      }
-
-      if (aCustomizing) {
-        CustomizableUI.registerMenuPanel(this.contents);
-      } else {
-        this.beginBatchUpdate();
-        try {
-          CustomizableUI.registerMenuPanel(this.contents);
-        } finally {
-          this.endBatchUpdate();
-        }
-      }
-      this._updateQuitTooltip();
-      this.panel.hidden = false;
-      this._isReady = true;
-    }.bind(this)).then(null, Cu.reportError);
-
-    return this._readyPromise;
-  },
-
-  /**
-   * Switch the panel to the main view if it's not already
-   * in that view.
-   */
-  showMainView: function() {
-    this._ensureEventListenersAdded();
-    this.multiView.showMainView();
-  },
-
-  /**
-   * Switch the panel to the help view if it's not already
-   * in that view.
-   */
-  showHelpView: function(aAnchor) {
-    this._ensureEventListenersAdded();
-    this.multiView.showSubView("PanelUI-helpView", aAnchor);
-  },
-
-  /**
-   * Shows a subview in the panel with a given ID.
-   *
-   * @param aViewId the ID of the subview to show.
-   * @param aAnchor the element that spawned the subview.
-   * @param aPlacementArea the CustomizableUI area that aAnchor is in.
-   */
-  showSubView: Task.async(function*(aViewId, aAnchor, aPlacementArea) {
-    this._ensureEventListenersAdded();
-    let viewNode = document.getElementById(aViewId);
-    if (!viewNode) {
-      Cu.reportError("Could not show panel subview with id: " + aViewId);
-      return;
-    }
-
-    if (!aAnchor) {
-      Cu.reportError("Expected an anchor when opening subview with id: " + aViewId);
-      return;
-    }
-
-    if (aPlacementArea == CustomizableUI.AREA_PANEL) {
-      this.multiView.showSubView(aViewId, aAnchor);
-    } else if (!aAnchor.open) {
-      aAnchor.open = true;
-
-      let tempPanel = document.createElement("panel");
-      tempPanel.setAttribute("type", "arrow");
-      tempPanel.setAttribute("id", "customizationui-widget-panel");
-      tempPanel.setAttribute("class", "cui-widget-panel");
-      tempPanel.setAttribute("viewId", aViewId);
-      if (aAnchor.getAttribute("tabspecific")) {
-        tempPanel.setAttribute("tabspecific", true);
-      }
-      if (this._disableAnimations) {
-        tempPanel.setAttribute("animate", "false");
-      }
-      tempPanel.setAttribute("context", "");
-      document.getElementById(CustomizableUI.AREA_NAVBAR).appendChild(tempPanel);
-      // If the view has a footer, set a convenience class on the panel.
-      tempPanel.classList.toggle("cui-widget-panelWithFooter",
-                                 viewNode.querySelector(".panel-subview-footer"));
-
-      let multiView = document.createElement("panelmultiview");
-      multiView.setAttribute("id", "customizationui-widget-multiview");
-      multiView.setAttribute("nosubviews", "true");
-      tempPanel.appendChild(multiView);
-      multiView.setAttribute("mainViewIsSubView", "true");
-      multiView.setMainView(viewNode);
-      viewNode.classList.add("cui-widget-panelview");
-
-      let viewShown = false;
-      let panelRemover = () => {
-        viewNode.classList.remove("cui-widget-panelview");
-        if (viewShown) {
-          CustomizableUI.removePanelCloseListeners(tempPanel);
-          tempPanel.removeEventListener("popuphidden", panelRemover);
-
-          let evt = new CustomEvent("ViewHiding", {detail: viewNode});
-          viewNode.dispatchEvent(evt);
-        }
-        aAnchor.open = false;
-
-        this.multiView.appendChild(viewNode);
-        tempPanel.remove();
-      };
-
-      // Emit the ViewShowing event so that the widget definition has a chance
-      // to lazily populate the subview with things.
-      let detail = {
-        blockers: new Set(),
-        addBlocker(aPromise) {
-          this.blockers.add(aPromise);
-        },
-      };
-
-      let evt = new CustomEvent("ViewShowing", { bubbles: true, cancelable: true, detail });
-      viewNode.dispatchEvent(evt);
-
-      let cancel = evt.defaultPrevented;
-      if (detail.blockers.size) {
-        try {
-          let results = yield Promise.all(detail.blockers);
-          cancel = cancel || results.some(val => val === false);
-        } catch (e) {
-          Components.utils.reportError(e);
-          cancel = true;
-        }
-      }
-
-      if (cancel) {
-        panelRemover();
-        return;
-      }
-
-      viewShown = true;
-      CustomizableUI.addPanelCloseListeners(tempPanel);
-      tempPanel.addEventListener("popuphidden", panelRemover);
-
-      let iconAnchor =
-        document.getAnonymousElementByAttribute(aAnchor, "class",
-                                                "toolbarbutton-icon");
-
-      if (iconAnchor && aAnchor.id) {
-        iconAnchor.setAttribute("consumeanchor", aAnchor.id);
-      }
-      tempPanel.openPopup(iconAnchor || aAnchor, "bottomcenter topright");
-    }
-  }),
-
-  /**
-   * NB: The enable- and disableSingleSubviewPanelAnimations methods only
-   * affect the hiding/showing animations of single-subview panels (tempPanel
-   * in the showSubView method).
-   */
-  disableSingleSubviewPanelAnimations: function() {
-    this._disableAnimations = true;
-  },
-
-  enableSingleSubviewPanelAnimations: function() {
-    this._disableAnimations = false;
-  },
-
-  onWidgetAfterDOMChange: function(aNode, aNextNode, aContainer, aWasRemoval) {
-    if (aContainer != this.contents) {
-      return;
-    }
-    if (aWasRemoval) {
-      aNode.removeAttribute("auto-hyphens");
-    }
-  },
-
-  onWidgetBeforeDOMChange: function(aNode, aNextNode, aContainer, aIsRemoval) {
-    if (aContainer != this.contents) {
-      return;
-    }
-    if (!aIsRemoval &&
-        (this.panel.state == "open" ||
-         document.documentElement.hasAttribute("customizing"))) {
-      this._adjustLabelsForAutoHyphens(aNode);
-    }
-  },
-
-  /**
-   * Signal that we're about to make a lot of changes to the contents of the
-   * panels all at once. For performance, we ignore the mutations.
-   */
-  beginBatchUpdate: function() {
-    this._ensureEventListenersAdded();
-    this.multiView.ignoreMutations = true;
-  },
-
-  /**
-   * Signal that we're done making bulk changes to the panel. We now pay
-   * attention to mutations. This automatically synchronizes the multiview
-   * container with whichever view is displayed if the panel is open.
-   */
-  endBatchUpdate: function(aReason) {
-    this._ensureEventListenersAdded();
-    this.multiView.ignoreMutations = false;
-  },
-
-  _adjustLabelsForAutoHyphens: function(aNode) {
-    let toolbarButtons = aNode ? [aNode] :
-                                 this.contents.querySelectorAll(".toolbarbutton-1");
-    for (let node of toolbarButtons) {
-      let label = node.getAttribute("label");
-      if (!label) {
-        continue;
-      }
-      if (label.includes("\u00ad")) {
-        node.setAttribute("auto-hyphens", "off");
-      } else {
-        node.removeAttribute("auto-hyphens");
-      }
-    }
-  },
-
-  /**
-   * Sets the anchor node into the open or closed state, depending
-   * on the state of the panel.
-   */
-  _updatePanelButton: function() {
-    this.menuButton.open = this.panel.state == "open" ||
-                           this.panel.state == "showing";
-  },
-
-  _onHelpViewShow: function(aEvent) {
-    // Call global menu setup function
-    buildHelpMenu();
-
-    let helpMenu = document.getElementById("menu_HelpPopup");
-    let items = this.getElementsByTagName("vbox")[0];
-    let attrs = ["oncommand", "onclick", "label", "key", "disabled"];
-    let NSXUL = "http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul";
-
-    // Remove all buttons from the view
-    while (items.firstChild) {
-      items.removeChild(items.firstChild);
-    }
-
-    // Add the current set of menuitems of the Help menu to this view
-    let menuItems = Array.prototype.slice.call(helpMenu.getElementsByTagName("menuitem"));
-    let fragment = document.createDocumentFragment();
-    for (let node of menuItems) {
-      if (node.hidden)
-        continue;
-      let button = document.createElementNS(NSXUL, "toolbarbutton");
-      // Copy specific attributes from a menuitem of the Help menu
-      for (let attrName of attrs) {
-        if (!node.hasAttribute(attrName))
-          continue;
-        button.setAttribute(attrName, node.getAttribute(attrName));
-      }
-      button.setAttribute("class", "subviewbutton");
-      fragment.appendChild(button);
-    }
-    items.appendChild(fragment);
-  },
-
-  _updateQuitTooltip: function() {
-    if (AppConstants.platform == "win") {
-      return;
-    }
-
-    let tooltipId = AppConstants.platform == "macosx" ?
-                    "quit-button.tooltiptext.mac" :
-                    "quit-button.tooltiptext.linux2";
-
-    let brands = Services.strings.createBundle("chrome://branding/locale/brand.properties");
-    let stringArgs = [brands.GetStringFromName("brandShortName")];
-
-    let key = document.getElementById("key_quitApplication");
-    stringArgs.push(ShortcutUtils.prettifyShortcut(key));
-    let tooltipString = CustomizableUI.getLocalizedProperty({x: tooltipId}, "x", stringArgs);
-    let quitButton = document.getElementById("PanelUI-quit");
-    quitButton.setAttribute("tooltiptext", tooltipString);
-  },
-
-  _overlayScrollListenerBoundFn: null,
-  _overlayScrollListener: function(aMQL) {
-    ScrollbarSampler.resetSystemScrollbarWidth();
-    this._scrollWidth = null;
-  },
-};
-
-XPCOMUtils.defineConstant(this, "PanelUI", PanelUI);
-
-/**
- * Gets the currently selected locale for display.
- * @return  the selected locale or "en-US" if none is selected
- */
-function getLocale() {
-  try {
-    let chromeRegistry = Cc["@mozilla.org/chrome/chrome-registry;1"]
-                           .getService(Ci.nsIXULChromeRegistry);
-    return chromeRegistry.getSelectedLocale("browser");
-  } catch (ex) {
-    return "en-US";
-  }
-}
diff --git a/browser/components/customizableui/content/panelUI.xml b/browser/components/customizableui/content/panelUI.xml
deleted file mode 100644
index 6893bd8ff..000000000
--- a/browser/components/customizableui/content/panelUI.xml
+++ /dev/null
@@ -1,509 +0,0 @@
-<?xml version="1.0"?>
-<!-- This Source Code Form is subject to the terms of the Mozilla Public
-   - License, v. 2.0. If a copy of the MPL was not distributed with this
-   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
-
-<bindings id="browserPanelUIBindings"
-          xmlns="http://www.mozilla.org/xbl"
-          xmlns:xul="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
-          xmlns:xbl="http://www.mozilla.org/xbl">
-
-  <binding id="panelmultiview">
-    <resources>
-      <stylesheet src="chrome://browser/content/customizableui/panelUI.css"/>
-    </resources>
-    <content>
-      <xul:box anonid="viewContainer" class="panel-viewcontainer" xbl:inherits="panelopen,viewtype,transitioning">
-        <xul:stack anonid="viewStack" xbl:inherits="viewtype,transitioning" viewtype="main" class="panel-viewstack">
-          <xul:vbox anonid="mainViewContainer" class="panel-mainview" xbl:inherits="viewtype"/>
-
-          <!-- Used to capture click events over the PanelUI-mainView if we're in
-               subview mode. That way, any click on the PanelUI-mainView causes us
-               to revert to the mainView mode, whereupon PanelUI-click-capture then
-               allows click events to go through it. -->
-          <xul:vbox anonid="clickCapturer" class="panel-clickcapturer"/>
-
-          <!-- We manually set display: none (via a CSS attribute selector) on the
-               subviews that are not being displayed. We're using this over a deck
-               because a deck assumes the size of its largest child, regardless of
-               whether or not it is shown. That's not good for our case, since we
-               want to allow each subview to be uniquely sized. -->
-          <xul:vbox anonid="subViews" class="panel-subviews" xbl:inherits="panelopen">
-            <children includes="panelview"/>
-          </xul:vbox>
-        </xul:stack>
-      </xul:box>
-    </content>
-    <implementation implements="nsIDOMEventListener">
-      <field name="_clickCapturer" readonly="true">
-        document.getAnonymousElementByAttribute(this, "anonid", "clickCapturer");
-      </field>
-      <field name="_viewContainer" readonly="true">
-        document.getAnonymousElementByAttribute(this, "anonid", "viewContainer");
-      </field>
-      <field name="_mainViewContainer" readonly="true">
-        document.getAnonymousElementByAttribute(this, "anonid", "mainViewContainer");
-      </field>
-      <field name="_subViews" readonly="true">
-        document.getAnonymousElementByAttribute(this, "anonid", "subViews");
-      </field>
-      <field name="_viewStack" readonly="true">
-        document.getAnonymousElementByAttribute(this, "anonid", "viewStack");
-      </field>
-      <field name="_panel" readonly="true">
-        this.parentNode;
-      </field>
-
-      <field name="_currentSubView">null</field>
-      <field name="_anchorElement">null</field>
-      <field name="_mainViewHeight">0</field>
-      <field name="_subViewObserver">null</field>
-      <field name="__transitioning">false</field>
-      <field name="_ignoreMutations">false</field>
-
-      <property name="showingSubView" readonly="true"
-                onget="return this._viewStack.getAttribute('viewtype') == 'subview'"/>
-      <property name="_mainViewId" onget="return this.getAttribute('mainViewId');" onset="this.setAttribute('mainViewId', val); return val;"/>
-      <property name="_mainView" readonly="true"
-                onget="return this._mainViewId ? document.getElementById(this._mainViewId) : null;"/>
-      <property name="showingSubViewAsMainView" readonly="true"
-                onget="return this.getAttribute('mainViewIsSubView') == 'true'"/>
-
-      <property name="ignoreMutations">
-        <getter>
-          return this._ignoreMutations;
-        </getter>
-        <setter><![CDATA[
-          this._ignoreMutations = val;
-          if (!val && this._panel.state == "open") {
-            if (this.showingSubView) {
-              this._syncContainerWithSubView();
-            } else {
-              this._syncContainerWithMainView();
-            }
-          }
-        ]]></setter>
-      </property>
-
-      <property name="_transitioning">
-        <getter>
-          return this.__transitioning;
-        </getter>
-        <setter><![CDATA[
-          this.__transitioning = val;
-          if (val) {
-            this.setAttribute("transitioning", "true");
-          } else {
-            this.removeAttribute("transitioning");
-          }
-        ]]></setter>
-      </property>
-      <constructor><![CDATA[
-        this._clickCapturer.addEventListener("click", this);
-        this._panel.addEventListener("popupshowing", this);
-        this._panel.addEventListener("popupshown", this);
-        this._panel.addEventListener("popuphidden", this);
-        this._subViews.addEventListener("overflow", this);
-        this._mainViewContainer.addEventListener("overflow", this);
-
-        // Get a MutationObserver ready to react to subview size changes. We
-        // only attach this MutationObserver when a subview is being displayed.
-        this._subViewObserver =
-          new MutationObserver(this._syncContainerWithSubView.bind(this));
-        this._mainViewObserver =
-          new MutationObserver(this._syncContainerWithMainView.bind(this));
-
-        this._mainViewContainer.setAttribute("panelid",
-                                             this._panel.id);
-
-        if (this._mainView) {
-          this.setMainView(this._mainView);
-        }
-        this.setAttribute("viewtype", "main");
-      ]]></constructor>
-
-      <destructor><![CDATA[
-        if (this._mainView) {
-          this._mainView.removeAttribute("mainview");
-        }
-        this._mainViewObserver.disconnect();
-        this._subViewObserver.disconnect();
-        this._panel.removeEventListener("popupshowing", this);
-        this._panel.removeEventListener("popupshown", this);
-        this._panel.removeEventListener("popuphidden", this);
-        this._subViews.removeEventListener("overflow", this);
-        this._mainViewContainer.removeEventListener("overflow", this);
-        this._clickCapturer.removeEventListener("click", this);
-      ]]></destructor>
-
-      <method name="setMainView">
-        <parameter name="aNewMainView"/>
-        <body><![CDATA[
-        if (this._mainView) {
-          this._mainViewObserver.disconnect();
-          this._subViews.appendChild(this._mainView);
-          this._mainView.removeAttribute("mainview");
-        }
-        this._mainViewId = aNewMainView.id;
-        aNewMainView.setAttribute("mainview", "true");
-        this._mainViewContainer.appendChild(aNewMainView);
-        ]]></body>
-      </method>
-
-      <method name="showMainView">
-        <body><![CDATA[
-          if (this.showingSubView) {
-            let viewNode = this._currentSubView;
-            let evt = document.createEvent("CustomEvent");
-            evt.initCustomEvent("ViewHiding", true, true, viewNode);
-            viewNode.dispatchEvent(evt);
-
-            viewNode.removeAttribute("current");
-            this._currentSubView = null;
-
-            this._subViewObserver.disconnect();
-
-            this._setViewContainerHeight(this._mainViewHeight);
-
-            this.setAttribute("viewtype", "main");
-          }
-
-          this._shiftMainView();
-        ]]></body>
-      </method>
-
-      <method name="showSubView">
-        <parameter name="aViewId"/>
-        <parameter name="aAnchor"/>
-        <body><![CDATA[
-          Task.spawn(function*() {
-            let viewNode = this.querySelector("#" + aViewId);
-            viewNode.setAttribute("current", true);
-            // Emit the ViewShowing event so that the widget definition has a chance
-            // to lazily populate the subview with things.
-            let detail = {
-              blockers: new Set(),
-              addBlocker(aPromise) {
-                this.blockers.add(aPromise);
-              },
-            };
-
-            let evt = new CustomEvent("ViewShowing", { bubbles: true, cancelable: true, detail });
-            viewNode.dispatchEvent(evt);
-
-            let cancel = evt.defaultPrevented;
-            if (detail.blockers.size) {
-              try {
-                let results = yield Promise.all(detail.blockers);
-                cancel = cancel || results.some(val => val === false);
-              } catch (e) {
-                Components.utils.reportError(e);
-                cancel = true;
-              }
-            }
-
-            if (cancel) {
-              return;
-            }
-
-            this._currentSubView = viewNode;
-
-            // Now we have to transition the panel. There are a few parts to this:
-            //
-            // 1) The main view content gets shifted so that the center of the anchor
-            //    node is at the left-most edge of the panel.
-            // 2) The subview deck slides in so that it takes up almost all of the
-            //    panel.
-            // 3) If the subview is taller then the main panel contents, then the panel
-            //    must grow to meet that new height. Otherwise, it must shrink.
-            //
-            // All three of these actions make use of CSS transformations, so they
-            // should all occur simultaneously.
-            this.setAttribute("viewtype", "subview");
-            this._shiftMainView(aAnchor);
-
-            this._mainViewHeight = this._viewStack.clientHeight;
-
-            let newHeight = this._heightOfSubview(viewNode, this._subViews);
-            this._setViewContainerHeight(newHeight);
-
-            this._subViewObserver.observe(viewNode, {
-              attributes: true,
-              characterData: true,
-              childList: true,
-              subtree: true
-            });
-          }.bind(this));
-        ]]></body>
-      </method>
-
-      <method name="_setViewContainerHeight">
-        <parameter name="aHeight"/>
-        <body><![CDATA[
-          let container = this._viewContainer;
-          this._transitioning = true;
-
-          let onTransitionEnd = () => {
-            container.removeEventListener("transitionend", onTransitionEnd);
-            this._transitioning = false;
-          };
-
-          container.addEventListener("transitionend", onTransitionEnd);
-          container.style.height = `${aHeight}px`;
-        ]]></body>
-      </method>
-
-      <method name="_shiftMainView">
-        <parameter name="aAnchor"/>
-        <body><![CDATA[
-          if (aAnchor) {
-            // We need to find the edge of the anchor, relative to the main panel.
-            // Then we need to add half the width of the anchor. This is the target
-            // that we need to transition to.
-            let anchorRect = aAnchor.getBoundingClientRect();
-            let mainViewRect = this._mainViewContainer.getBoundingClientRect();
-            let center = aAnchor.clientWidth / 2;
-            let direction = aAnchor.ownerDocument.defaultView.getComputedStyle(aAnchor, null).direction;
-            let edge;
-            if (direction == "ltr") {
-              edge = anchorRect.left - mainViewRect.left;
-            } else {
-              edge = mainViewRect.right - anchorRect.right;
-            }
-
-            // If the anchor is an element on the far end of the mainView we
-            // don't want to shift the mainView too far, we would reveal empty
-            // space otherwise.
-            let cstyle = window.getComputedStyle(document.documentElement, null);
-            let exitSubViewGutterWidth =
-              cstyle.getPropertyValue("--panel-ui-exit-subview-gutter-width");
-            let maxShift = mainViewRect.width - parseInt(exitSubViewGutterWidth);
-            let target = Math.min(maxShift, edge + center);
-
-            let neg = direction == "ltr" ? "-" : "";
-            this._mainViewContainer.style.transform = `translateX(${neg}${target}px)`;
-            aAnchor.setAttribute("panel-multiview-anchor", true);
-          } else {
-            this._mainViewContainer.style.transform = "";
-            if (this.anchorElement)
-              this.anchorElement.removeAttribute("panel-multiview-anchor");
-          }
-          this.anchorElement = aAnchor;
-        ]]></body>
-      </method>
-
-      <method name="handleEvent">
-        <parameter name="aEvent"/>
-        <body><![CDATA[
-          if (aEvent.type.startsWith("popup") && aEvent.target != this._panel) {
-            // Shouldn't act on e.g. context menus being shown from within the panel.
-            return;
-          }
-          switch (aEvent.type) {
-            case "click":
-              if (aEvent.originalTarget == this._clickCapturer) {
-                this.showMainView();
-              }
-              break;
-            case "overflow":
-              if (aEvent.target.localName == "vbox") {
-                // Resize the right view on the next tick.
-                if (this.showingSubView) {
-                  setTimeout(this._syncContainerWithSubView.bind(this), 0);
-                } else if (!this.transitioning) {
-                  setTimeout(this._syncContainerWithMainView.bind(this), 0);
-                }
-              }
-              break;
-            case "popupshowing":
-              this.setAttribute("panelopen", "true");
-              // Bug 941196 - The panel can get taller when opening a subview. Disabling
-              // autoPositioning means that the panel won't jump around if an opened
-              // subview causes the panel to exceed the dimensions of the screen in the
-              // direction that the panel originally opened in. This property resets
-              // every time the popup closes, which is why we have to set it each time.
-              this._panel.autoPosition = false;
-              this._syncContainerWithMainView();
-
-              this._mainViewObserver.observe(this._mainView, {
-                attributes: true,
-                characterData: true,
-                childList: true,
-                subtree: true
-              });
-
-              break;
-            case "popupshown":
-              this._setMaxHeight();
-              break;
-            case "popuphidden":
-              this.removeAttribute("panelopen");
-              this._mainView.style.removeProperty("height");
-              this.showMainView();
-              this._mainViewObserver.disconnect();
-              break;
-          }
-        ]]></body>
-      </method>
-
-      <method name="_shouldSetPosition">
-        <body><![CDATA[
-          return this.getAttribute("nosubviews") == "true";
-        ]]></body>
-      </method>
-
-      <method name="_shouldSetHeight">
-        <body><![CDATA[
-          return this.getAttribute("nosubviews") != "true";
-        ]]></body>
-      </method>
-
-      <method name="_setMaxHeight">
-        <body><![CDATA[
-          if (!this._shouldSetHeight())
-            return;
-
-          // Ignore the mutation that'll fire when we set the height of
-          // the main view.
-          this.ignoreMutations = true;
-          this._mainView.style.height =
-            this.getBoundingClientRect().height + "px";
-          this.ignoreMutations = false;
-        ]]></body>
-      </method>
-      <method name="_adjustContainerHeight">
-        <body><![CDATA[
-          if (!this.ignoreMutations && !this.showingSubView && !this._transitioning) {
-            let height;
-            if (this.showingSubViewAsMainView) {
-              height = this._heightOfSubview(this._mainView);
-            } else {
-              height = this._mainView.scrollHeight;
-            }
-            this._viewContainer.style.height = height + "px";
-          }
-        ]]></body>
-      </method>
-      <method name="_syncContainerWithSubView">
-        <body><![CDATA[
-          // Check that this panel is still alive:
-          if (!this._panel || !this._panel.parentNode) {
-            return;
-          }
-
-          if (!this.ignoreMutations && this.showingSubView) {
-            let newHeight = this._heightOfSubview(this._currentSubView, this._subViews);
-            this._viewContainer.style.height = newHeight + "px";
-          }
-        ]]></body>
-      </method>
-      <method name="_syncContainerWithMainView">
-        <body><![CDATA[
-          // Check that this panel is still alive:
-          if (!this._panel || !this._panel.parentNode) {
-            return;
-          }
-
-          if (this._shouldSetPosition()) {
-            this._panel.adjustArrowPosition();
-          }
-
-          if (this._shouldSetHeight()) {
-            this._adjustContainerHeight();
-          }
-        ]]></body>
-      </method>
-
-      <!-- Call this when the height of one of your views (the main view or a
-           subview) changes and you want the heights of the multiview and panel
-           to be the same as the view's height.
-           If the caller can give a hint of the expected height change with the
-           optional aExpectedChange parameter, it prevents flicker. -->
-      <method name="setHeightToFit">
-        <parameter name="aExpectedChange"/>
-        <body><![CDATA[
-          // Set the max-height to zero, wait until the height is actually
-          // updated, and then remove it.  If it's not removed, weird things can
-          // happen, like widgets in the panel won't respond to clicks even
-          // though they're visible.
-          let count = 5;
-          let height = getComputedStyle(this).height;
-          if (aExpectedChange)
-            this.style.maxHeight = (parseInt(height) + aExpectedChange) + "px";
-          else
-            this.style.maxHeight = "0";
-          let interval = setInterval(() => {
-            if (height != getComputedStyle(this).height || --count == 0) {
-              clearInterval(interval);
-              this.style.removeProperty("max-height");
-            }
-          }, 0);
-        ]]></body>
-      </method>
-
-      <method name="_heightOfSubview">
-        <parameter name="aSubview"/>
-        <parameter name="aContainerToCheck"/>
-        <body><![CDATA[
-          function getFullHeight(element) {
-            // XXXgijs: unfortunately, scrollHeight rounds values, and there's no alternative
-            // that works with overflow: auto elements. Fortunately for us,
-            // we have exactly 1 (potentially) scrolling element in here (the subview body),
-            // and rounding 1 value is OK - rounding more than 1 and adding them means we get
-            // off-by-1 errors. Now we might be off by a subpixel, but we care less about that.
-            // So, use scrollHeight *only* if the element is vertically scrollable.
-            let height;
-            let elementCS;
-            if (element.scrollTopMax) {
-              height = element.scrollHeight;
-              // Bounding client rects include borders, scrollHeight doesn't:
-              elementCS = win.getComputedStyle(element);
-              height += parseFloat(elementCS.borderTopWidth) +
-                        parseFloat(elementCS.borderBottomWidth);
-            } else {
-              height = element.getBoundingClientRect().height;
-              if (height > 0) {
-                elementCS = win.getComputedStyle(element);
-              }
-            }
-            if (elementCS) {
-              // Include margins - but not borders or paddings because they
-              // were dealt with above.
-              height += parseFloat(elementCS.marginTop) + parseFloat(elementCS.marginBottom);
-            }
-            return height;
-          }
-          let win = aSubview.ownerDocument.defaultView;
-          let body = aSubview.querySelector(".panel-subview-body");
-          let height = getFullHeight(body || aSubview);
-          if (body) {
-            let header = aSubview.querySelector(".panel-subview-header");
-            let footer = aSubview.querySelector(".panel-subview-footer");
-            height += (header ? getFullHeight(header) : 0) +
-                      (footer ? getFullHeight(footer) : 0);
-          }
-          if (aContainerToCheck) {
-            let containerCS = win.getComputedStyle(aContainerToCheck);
-            height += parseFloat(containerCS.paddingTop) + parseFloat(containerCS.paddingBottom);
-          }
-          return Math.ceil(height);
-        ]]></body>
-      </method>
-
-    </implementation>
-  </binding>
-
-  <binding id="panelview">
-    <implementation>
-      <property name="panelMultiView" readonly="true">
-        <getter><![CDATA[
-          if (this.parentNode.localName != "panelmultiview") {
-            return document.getBindingParent(this.parentNode);
-          }
-
-          return this.parentNode;
-        ]]></getter>
-      </property>
-    </implementation>
-  </binding>
-</bindings>
diff --git a/browser/components/customizableui/content/toolbar.xml b/browser/components/customizableui/content/toolbar.xml
deleted file mode 100644
index 4e6964c9f..000000000
--- a/browser/components/customizableui/content/toolbar.xml
+++ /dev/null
@@ -1,618 +0,0 @@
-<?xml version="1.0"?>
-<!-- This Source Code Form is subject to the terms of the Mozilla Public
-   - License, v. 2.0. If a copy of the MPL was not distributed with this
-   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
-
-<bindings id="browserToolbarBindings"
-          xmlns="http://www.mozilla.org/xbl"
-          xmlns:xul="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
-          xmlns:xbl="http://www.mozilla.org/xbl">
-
-  <binding id="toolbar" role="xul:toolbar">
-    <resources>
-      <stylesheet src="chrome://global/skin/toolbar.css"/>
-    </resources>
-    <implementation>
-      <field name="overflowedDuringConstruction">null</field>
-
-      <constructor><![CDATA[
-          let scope = {};
-          Cu.import("resource:///modules/CustomizableUI.jsm", scope);
-          // Add an early overflow event listener that will mark if the
-          // toolbar overflowed during construction.
-          if (scope.CustomizableUI.isAreaOverflowable(this.id)) {
-            this.addEventListener("overflow", this);
-            this.addEventListener("underflow", this);
-          }
-
-          if (document.readyState == "complete") {
-            this._init();
-          } else {
-            // Need to wait until XUL overlays are loaded. See bug 554279.
-            let self = this;
-            document.addEventListener("readystatechange", function onReadyStateChange() {
-              if (document.readyState != "complete")
-                return;
-              document.removeEventListener("readystatechange", onReadyStateChange, false);
-              self._init();
-            }, false);
-          }
-      ]]></constructor>
-
-      <method name="_init">
-        <body><![CDATA[
-          let scope = {};
-          Cu.import("resource:///modules/CustomizableUI.jsm", scope);
-          let CustomizableUI = scope.CustomizableUI;
-
-          // Bug 989289: Forcibly set the now unsupported "mode" and "iconsize"
-          // attributes, just in case they accidentally get restored from
-          // persistence from a user that's been upgrading and downgrading.
-          if (CustomizableUI.isBuiltinToolbar(this.id)) {
-            const kAttributes = new Map([["mode", "icons"], ["iconsize", "small"]]);
-            for (let [attribute, value] of kAttributes) {
-              if (this.getAttribute(attribute) != value) {
-                this.setAttribute(attribute, value);
-                document.persist(this.id, attribute);
-              }
-              if (this.toolbox) {
-                if (this.toolbox.getAttribute(attribute) != value) {
-                  this.toolbox.setAttribute(attribute, value);
-                  document.persist(this.toolbox.id, attribute);
-                }
-              }
-            }
-          }
-
-          // Searching for the toolbox palette in the toolbar binding because
-          // toolbars are constructed first.
-          let toolbox = this.toolbox;
-          if (toolbox && !toolbox.palette) {
-            for (let node of toolbox.children) {
-              if (node.localName == "toolbarpalette") {
-                // Hold on to the palette but remove it from the document.
-                toolbox.palette = node;
-                toolbox.removeChild(node);
-                break;
-              }
-            }
-          }
-
-          // pass the current set of children for comparison with placements:
-          let children = Array.from(this.childNodes)
-                              .filter(node => node.getAttribute("skipintoolbarset") != "true" && node.id)
-                              .map(node => node.id);
-          CustomizableUI.registerToolbarNode(this, children);
-        ]]></body>
-      </method>
-
-      <method name="handleEvent">
-        <parameter name="aEvent"/>
-        <body><![CDATA[
-          if (aEvent.type == "overflow" && aEvent.detail > 0) {
-            if (this.overflowable && this.overflowable.initialized) {
-              this.overflowable.onOverflow(aEvent);
-            } else {
-              this.overflowedDuringConstruction = aEvent;
-            }
-          } else if (aEvent.type == "underflow" && aEvent.detail > 0) {
-            this.overflowedDuringConstruction = null;
-          }
-        ]]></body>
-      </method>
-
-      <method name="insertItem">
-        <parameter name="aId"/>
-        <parameter name="aBeforeElt"/>
-        <parameter name="aWrapper"/>
-        <body><![CDATA[
-          if (aWrapper) {
-            Cu.reportError("Can't insert " + aId + ": using insertItem " +
-                           "no longer supports wrapper elements.");
-            return null;
-          }
-
-          // Hack, the customizable UI code makes this be the last position
-          let pos = null;
-          if (aBeforeElt) {
-            let beforeInfo = CustomizableUI.getPlacementOfWidget(aBeforeElt.id);
-            if (beforeInfo.area != this.id) {
-              Cu.reportError("Can't insert " + aId + " before " +
-                             aBeforeElt.id + " which isn't in this area (" +
-                             this.id + ").");
-              return null;
-            }
-            pos = beforeInfo.position;
-          }
-
-          CustomizableUI.addWidgetToArea(aId, this.id, pos);
-          return this.ownerDocument.getElementById(aId);
-        ]]></body>
-      </method>
-
-      <property name="toolbarName"
-                onget="return this.getAttribute('toolbarname');"
-                onset="this.setAttribute('toolbarname', val); return val;"/>
-
-      <property name="customizationTarget" readonly="true">
-        <getter><![CDATA[
-          if (this._customizationTarget)
-            return this._customizationTarget;
-
-          let id = this.getAttribute("customizationtarget");
-          if (id)
-            this._customizationTarget = document.getElementById(id);
-
-          if (this._customizationTarget)
-            this._customizationTarget.insertItem = this.insertItem.bind(this);
-          else
-            this._customizationTarget = this;
-
-          return this._customizationTarget;
-        ]]></getter>
-      </property>
-
-      <property name="toolbox" readonly="true">
-        <getter><![CDATA[
-          if (this._toolbox)
-            return this._toolbox;
-
-          let toolboxId = this.getAttribute("toolboxid");
-          if (toolboxId) {
-            let toolbox = document.getElementById(toolboxId);
-            if (toolbox) {
-              if (toolbox.externalToolbars.indexOf(this) == -1)
-                toolbox.externalToolbars.push(this);
-
-              this._toolbox = toolbox;
-            }
-          }
-
-          if (!this._toolbox && this.parentNode &&
-              this.parentNode.localName == "toolbox") {
-            this._toolbox = this.parentNode;
-          }
-
-          return this._toolbox;
-        ]]></getter>
-      </property>
-
-      <property name="currentSet">
-        <getter><![CDATA[
-          let currentWidgets = new Set();
-          for (let node of this.customizationTarget.children) {
-            let realNode = node.localName == "toolbarpaletteitem" ? node.firstChild : node;
-            if (realNode.getAttribute("skipintoolbarset") != "true") {
-              currentWidgets.add(realNode.id);
-            }
-          }
-          if (this.getAttribute("overflowing") == "true") {
-            let overflowTarget = this.getAttribute("overflowtarget");
-            let overflowList = this.ownerDocument.getElementById(overflowTarget);
-            for (let node of overflowList.children) {
-              let realNode = node.localName == "toolbarpaletteitem" ? node.firstChild : node;
-              if (realNode.getAttribute("skipintoolbarset") != "true") {
-                currentWidgets.add(realNode.id);
-              }
-            }
-          }
-          let orderedPlacements = CustomizableUI.getWidgetIdsInArea(this.id);
-          return orderedPlacements.filter((x) => currentWidgets.has(x)).join(',');
-        ]]></getter>
-        <setter><![CDATA[
-          // Get list of new and old ids:
-          let newVal = (val || '').split(',').filter(x => x);
-          let oldIds = CustomizableUI.getWidgetIdsInArea(this.id);
-
-          // Get a list of items only in the new list
-          let newIds = newVal.filter(id => oldIds.indexOf(id) == -1);
-          CustomizableUI.beginBatchUpdate();
-          try {
-            for (let newId of newIds) {
-              oldIds = CustomizableUI.getWidgetIdsInArea(this.id);
-              let nextId = newId;
-              let pos;
-              do {
-                // Get the next item
-                nextId = newVal[newVal.indexOf(nextId) + 1];
-                // Figure out where it is in the old list
-                pos = oldIds.indexOf(nextId);
-                // If it's not in the old list, repeat:
-              } while (pos == -1 && nextId);
-              if (pos == -1) {
-                pos = null; // We didn't find anything, insert at the end
-              }
-              CustomizableUI.addWidgetToArea(newId, this.id, pos);
-            }
-
-            let currentIds = this.currentSet.split(',');
-            let removedIds = currentIds.filter(id => newIds.indexOf(id) == -1 && newVal.indexOf(id) == -1);
-            for (let removedId of removedIds) {
-              CustomizableUI.removeWidgetFromArea(removedId);
-            }
-          } finally {
-            CustomizableUI.endBatchUpdate();
-          }
-        ]]></setter>
-      </property>
-
-
-    </implementation>
-  </binding>
-
-  <binding id="toolbar-menubar-stub">
-    <implementation>
-      <property name="toolbox" readonly="true">
-        <getter><![CDATA[
-          if (this._toolbox)
-            return this._toolbox;
-
-          if (this.parentNode && this.parentNode.localName == "toolbox") {
-            this._toolbox = this.parentNode;
-          }
-
-          return this._toolbox;
-        ]]></getter>
-      </property>
-      <property name="currentSet" readonly="true">
-        <getter><![CDATA[
-          return this.getAttribute("defaultset");
-        ]]></getter>
-      </property>
-      <method name="insertItem">
-        <body><![CDATA[
-          return null;
-        ]]></body>
-      </method>
-    </implementation>
-  </binding>
-
-  <!-- The toolbar-menubar-autohide and toolbar-drag bindings are almost
-       verbatim copies of their toolkit counterparts - they just inherit from
-       the customizableui's toolbar binding instead of toolkit's. We're currently
-       OK with the maintainance burden of having two copies of a binding, since
-       the long term goal is to move the customization framework into toolkit. -->
-
-  <binding id="toolbar-menubar-autohide"
-           extends="chrome://browser/content/customizableui/toolbar.xml#toolbar">
-    <implementation>
-      <constructor>
-        this._setInactive();
-      </constructor>
-      <destructor>
-        this._setActive();
-      </destructor>
-
-      <field name="_inactiveTimeout">null</field>
-
-      <field name="_contextMenuListener"><![CDATA[({
-        toolbar: this,
-        contextMenu: null,
-
-        get active () {
-          return !!this.contextMenu;
-        },
-
-        init: function (event) {
-          let node = event.target;
-          while (node != this.toolbar) {
-            if (node.localName == "menupopup")
-              return;
-            node = node.parentNode;
-          }
-
-          let contextMenuId = this.toolbar.getAttribute("context");
-          if (!contextMenuId)
-            return;
-
-          this.contextMenu = document.getElementById(contextMenuId);
-          if (!this.contextMenu)
-            return;
-
-          this.contextMenu.addEventListener("popupshown", this, false);
-          this.contextMenu.addEventListener("popuphiding", this, false);
-          this.toolbar.addEventListener("mousemove", this, false);
-        },
-        handleEvent: function (event) {
-          switch (event.type) {
-            case "popupshown":
-              this.toolbar.removeEventListener("mousemove", this, false);
-              break;
-            case "popuphiding":
-            case "mousemove":
-              this.toolbar._setInactiveAsync();
-              this.toolbar.removeEventListener("mousemove", this, false);
-              this.contextMenu.removeEventListener("popuphiding", this, false);
-              this.contextMenu.removeEventListener("popupshown", this, false);
-              this.contextMenu = null;
-              break;
-          }
-        }
-      })]]></field>
-
-      <method name="_setInactive">
-        <body><![CDATA[
-          this.setAttribute("inactive", "true");
-        ]]></body>
-      </method>
-
-      <method name="_setInactiveAsync">
-        <body><![CDATA[
-          this._inactiveTimeout = setTimeout(function (self) {
-            if (self.getAttribute("autohide") == "true") {
-              self._inactiveTimeout = null;
-              self._setInactive();
-            }
-          }, 0, this);
-        ]]></body>
-      </method>
-
-      <method name="_setActive">
-        <body><![CDATA[
-          if (this._inactiveTimeout) {
-            clearTimeout(this._inactiveTimeout);
-            this._inactiveTimeout = null;
-          }
-          this.removeAttribute("inactive");
-        ]]></body>
-      </method>
-    </implementation>
-
-    <handlers>
-      <handler event="DOMMenuBarActive"     action="this._setActive();"/>
-      <handler event="popupshowing"         action="this._setActive();"/>
-      <handler event="mousedown" button="2" action="this._contextMenuListener.init(event);"/>
-      <handler event="DOMMenuBarInactive"><![CDATA[
-        if (!this._contextMenuListener.active)
-          this._setInactiveAsync();
-      ]]></handler>
-    </handlers>
-  </binding>
-
-  <binding id="toolbar-drag"
-           extends="chrome://browser/content/customizableui/toolbar.xml#toolbar">
-    <implementation>
-      <field name="_dragBindingAlive">true</field>
-      <constructor><![CDATA[
-        if (!this._draggableStarted) {
-          this._draggableStarted = true;
-          try {
-            let tmp = {};
-            Components.utils.import("resource://gre/modules/WindowDraggingUtils.jsm", tmp);
-            let draggableThis = new tmp.WindowDraggingElement(this);
-            draggableThis.mouseDownCheck = function(e) {
-              return this._dragBindingAlive;
-            };
-          } catch (e) {}
-        }
-      ]]></constructor>
-    </implementation>
-  </binding>
-
-
-<!-- This is a peculiar binding. It is here to deal with overlayed/inserted add-on content,
-      and immediately direct such content elsewhere. -->
-  <binding id="addonbar-delegating">
-    <implementation>
-      <constructor><![CDATA[
-          // Reading these immediately so nobody messes with them anymore:
-          this._delegatingToolbar = this.getAttribute("toolbar-delegate");
-          this._wasCollapsed = this.getAttribute("collapsed") == "true";
-          // Leaving those in here to unbreak some code:
-          if (document.readyState == "complete") {
-            this._init();
-          } else {
-            // Need to wait until XUL overlays are loaded. See bug 554279.
-            let self = this;
-            document.addEventListener("readystatechange", function onReadyStateChange() {
-              if (document.readyState != "complete")
-                return;
-              document.removeEventListener("readystatechange", onReadyStateChange, false);
-              self._init();
-            }, false);
-          }
-      ]]></constructor>
-
-      <method name="_init">
-        <body><![CDATA[
-          // Searching for the toolbox palette in the toolbar binding because
-          // toolbars are constructed first.
-          let toolbox = this.toolbox;
-          if (toolbox && !toolbox.palette) {
-            for (let node of toolbox.children) {
-              if (node.localName == "toolbarpalette") {
-                // Hold on to the palette but remove it from the document.
-                toolbox.palette = node;
-                toolbox.removeChild(node);
-              }
-            }
-          }
-
-          // pass the current set of children for comparison with placements:
-          let children = [];
-          for (let node of this.childNodes) {
-            if (node.getAttribute("skipintoolbarset") != "true" && node.id) {
-              // Force everything to be removable so that buildArea can chuck stuff
-              // out if the user has customized things / we've been here before:
-              if (!this._whiteListed.has(node.id)) {
-                node.setAttribute("removable", "true");
-              }
-              children.push(node);
-            }
-          }
-          CustomizableUI.registerToolbarNode(this, children);
-          let existingMigratedItems = (this.getAttribute("migratedset") || "").split(',');
-          for (let migratedItem of existingMigratedItems.filter((x) => !!x)) {
-            this._currentSetMigrated.add(migratedItem);
-          }
-          this.evictNodes();
-          // We can't easily use |this| or strong bindings for the observer fn here
-          // because that creates leaky circular references when the node goes away,
-          // and XBL destructors are unreliable.
-          let mutationObserver = new MutationObserver(function(mutations) {
-            if (!mutations.length) {
-              return;
-            }
-            let toolbar = mutations[0].target;
-            // Can't use our own attribute because we might not have one if we're set to
-            // collapsed
-            let areCustomizing = toolbar.ownerDocument.documentElement.getAttribute("customizing");
-            if (!toolbar._isModifying && !areCustomizing) {
-              toolbar.evictNodes();
-            }
-          });
-          mutationObserver.observe(this, {childList: true});
-        ]]></body>
-      </method>
-      <method name="evictNodes">
-        <body><![CDATA[
-          this._isModifying = true;
-          let i = this.childNodes.length;
-          while (i--) {
-            let node = this.childNodes[i];
-            if (this.childNodes[i].id) {
-              this.evictNode(this.childNodes[i]);
-            } else {
-              node.remove();
-            }
-          }
-          this._isModifying = false;
-          this._updateMigratedSet();
-        ]]></body>
-      </method>
-      <method name="evictNode">
-        <parameter name="aNode"/>
-        <body>
-        <![CDATA[
-          if (this._whiteListed.has(aNode.id) || CustomizableUI.isSpecialWidget(aNode.id)) {
-            return;
-          }
-          const kItemMaxWidth = 100;
-          let oldParent = aNode.parentNode;
-          aNode.setAttribute("removable", "true");
-          this._currentSetMigrated.add(aNode.id);
-
-          let movedOut = false;
-          if (!this._wasCollapsed) {
-            try {
-              let nodeWidth = aNode.getBoundingClientRect().width;
-              if (nodeWidth == 0 || nodeWidth > kItemMaxWidth) {
-                throw new Error(aNode.id + " is too big (" + nodeWidth +
-                                "px wide), moving to the palette");
-              }
-              CustomizableUI.addWidgetToArea(aNode.id, this._delegatingToolbar);
-              movedOut = true;
-            } catch (ex) {
-              // This will throw if the node is too big, or can't be moved there for
-              // some reason. Report this:
-              Cu.reportError(ex);
-            }
-          }
-
-          /* We won't have moved the widget if either the add-on bar was collapsed,
-           * or if it was too wide to be inserted into the navbar. */
-          if (!movedOut) {
-            try {
-              CustomizableUI.removeWidgetFromArea(aNode.id);
-            } catch (ex) {
-              Cu.reportError(ex);
-              aNode.remove();
-            }
-          }
-
-          // Surprise: addWidgetToArea(palette) will get you nothing if the palette
-          // is not constructed yet. Fix:
-          if (aNode.parentNode == oldParent) {
-            let palette = this.toolbox.palette;
-            if (palette && oldParent != palette) {
-              palette.appendChild(aNode);
-            }
-          }
-        ]]></body>
-      </method>
-      <method name="insertItem">
-        <parameter name="aId"/>
-        <parameter name="aBeforeElt"/>
-        <parameter name="aWrapper"/>
-        <body><![CDATA[
-          if (aWrapper) {
-            Cu.reportError("Can't insert " + aId + ": using insertItem " +
-                           "no longer supports wrapper elements.");
-            return null;
-          }
-
-          let widget = CustomizableUI.getWidget(aId);
-          widget = widget && widget.forWindow(window);
-          let node = widget && widget.node;
-          if (!node) {
-            return null;
-          }
-
-          this._isModifying = true;
-          // Temporarily add it here so it can have a width, then ditch it:
-          this.appendChild(node);
-          this.evictNode(node);
-          this._isModifying = false;
-          this._updateMigratedSet();
-          // We will now have moved stuff around; kick off some events
-          // so add-ons know we've just moved their stuff:
-          // XXXgijs: only in this window. It's hard to know for sure what's the right
-          // thing to do here - typically insertItem is used on each window, so
-          // this seems to make the most sense, even if some of the effects of
-          // evictNode might affect multiple windows.
-          CustomizableUI.dispatchToolboxEvent("customizationchange", {}, window);
-          CustomizableUI.dispatchToolboxEvent("aftercustomization", {}, window);
-          return node;
-        ]]></body>
-      </method>
-      <method name="getMigratedItems">
-        <body><![CDATA[
-          return [... this._currentSetMigrated];
-        ]]></body>
-      </method>
-      <method name="_updateMigratedSet">
-        <body><![CDATA[
-          let newMigratedItems = this.getMigratedItems().join(',');
-          if (this.getAttribute("migratedset") != newMigratedItems) {
-            this.setAttribute("migratedset", newMigratedItems);
-            this.ownerDocument.persist(this.id, "migratedset");
-          }
-        ]]></body>
-      </method>
-      <property name="customizationTarget" readonly="true">
-        <getter><![CDATA[
-          return this;
-        ]]></getter>
-      </property>
-      <property name="currentSet">
-        <getter><![CDATA[
-          return Array.from(this.children, node => node.id).join(",");
-        ]]></getter>
-        <setter><![CDATA[
-          let v = val.split(',');
-          let newButtons = v.filter(x => x && (!this._whiteListed.has(x) &&
-                                               !CustomizableUI.isSpecialWidget(x) &&
-                                               !this._currentSetMigrated.has(x)));
-          for (let newButton of newButtons) {
-            this._currentSetMigrated.add(newButton);
-            this.insertItem(newButton);
-          }
-          this._updateMigratedSet();
-        ]]></setter>
-      </property>
-      <property name="toolbox" readonly="true">
-        <getter><![CDATA[
-          if (!this._toolbox && this.parentNode &&
-              this.parentNode.localName == "toolbox") {
-            this._toolbox = this.parentNode;
-          }
-
-          return this._toolbox;
-        ]]></getter>
-      </property>
-      <field name="_whiteListed" readonly="true">new Set(["addonbar-closebutton", "status-bar"])</field>
-      <field name="_isModifying">false</field>
-      <field name="_currentSetMigrated">new Set()</field>
-    </implementation>
-  </binding>
-</bindings>
diff --git a/browser/components/customizableui/moz.build b/browser/components/customizableui/moz.build
deleted file mode 100644
index 034630dc9..000000000
--- a/browser/components/customizableui/moz.build
+++ /dev/null
@@ -1,21 +0,0 @@
-# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
-# vim: set filetype=python:
-# 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/.
-
-DIRS += [
-    'content',
-]
-
-EXTRA_JS_MODULES += [
-    'CustomizableUI.jsm',
-    'CustomizableWidgets.jsm',
-    'CustomizeMode.jsm',
-    'DragPositionManager.jsm',
-    'PanelWideWidgetTracker.jsm',
-    'ScrollbarSampler.jsm',
-]
-
-if CONFIG['MOZ_WIDGET_TOOLKIT'] in ('windows', 'cocoa'):
-    DEFINES['CAN_DRAW_IN_TITLEBAR'] = 1