Issue 5315 - Add support for Microsoft Edge

ext/common.js

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-2017 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/>.
  */
 
 "use strict";
 
 (function()
 {
   // Both Edge and Mozilla Web Extensions use the namespace
   // 'browser' instead of 'chrome'. Edge has chrome namespace defined,
-  // but only with one property: 'app'.
-  if (!chrome || !chrome.extension)
+  // in some cases, but only with one property: 'app'.
+  if (typeof chrome == "undefined" || typeof chrome.extension == "undefined")
     window.chrome = window.browser;
 
   window.ext = {};
 
   let EventTarget = ext._EventTarget = function()
   {
     this._listeners = new Set();
   };
   EventTarget.prototype = {
     addListener(listener)
@@ skipping 38 matching lines @@
       return chrome.extension.getBackgroundPage();
     }
   };
 
 
   /* Utils */
 
   ext.getURL = chrome.extension.getURL;
   ext.i18n = chrome.i18n;
 }());