Issue 427 - Remove non-standard function and getter syntax

lib/customizableUI.js

 /*
  * This file is part of Adblock Plus <http://adblockplus.org/>,
  * Copyright (C) 2006-2014 Eyeo GmbH
  *
  * Adblock Plus is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 3 as
  * published by the Free Software Foundation.
  *
  * Adblock Plus is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with Adblock Plus.  If not, see <http://www.gnu.org/licenses/>.
  */
 
 /**
  * @fileOverview This emulates a subset of the CustomizableUI API from Firefox 28.
  */
 
 let {XPCOMUtils} = Cu.import("resource://gre/modules/XPCOMUtils.jsm", null);
 
 let {Utils} = require("utils");
 
 // UI module has to be referenced lazily to avoid circular references
-XPCOMUtils.defineLazyGetter(this, "UI", function() require("ui").UI);
+XPCOMUtils.defineLazyGetter(this, "UI", () => require("ui").UI);
 
 let widgets = Map();
 
 function getToolbox(/**Window*/ window, /**Widget*/ widget) /**Element*/
 {
   if (!("defaultArea" in widget) || !widget.defaultArea)
     return null;
 
   let toolbar = UI.findElement(window, widget.defaultArea);
   if (!toolbar)
@@ skipping 273 matching lines @@
     for (let [id, widget] of widgets)
     {
       let toolbox = getToolbox(window, widget);
       if (toolbox)
         toolbox.removeEventListener("aftercustomization", onToolbarCustomization, false);
 
       removeWidget(window, widget);
     }
   }
 });