Issue 5599 - ext needs to be defined in the postload script

ext/background.js

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-present 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
@@ skipping 728 matching lines @@
       // We are not using extension.getURL to get the absolute path here
       // because of the Edge issue:
       // https://developer.microsoft.com/en-us/microsoft-edge/platform/issues/10276332/
       let optionsUrl = "options.html";
       let fullOptionsUrl = ext.getURL(optionsUrl);
 
       chrome.tabs.query({}, tabs =>
       {
         // We find a tab ourselves because Edge has a bug when quering tabs
         // with extension URL protocol:
-        // https://developer.microsoft.com/en-us/microsoft-edge/platform/issues/8094141/ 
+        // https://developer.microsoft.com/en-us/microsoft-edge/platform/issues/8094141/

[hub, 2017/09/01 20:41:36]

only here to pass eslint (trailing space)

         // https://developer.microsoft.com/en-us/microsoft-edge/platform/issues/8604703/
         let tab = tabs.find(element => element.url == fullOptionsUrl);
         if (tab)
         {
           chrome.windows.update(tab.windowId, {focused: true});
           chrome.tabs.update(tab.id, {active: true});
 
           if (callback)
             callback(new Page(tab));
         }
@@ skipping 17 matching lines @@
   ext.windows = {
     create(createData, callback)
     {
       chrome.windows.create(createData, createdWindow =>
       {
         afterTabLoaded(callback)(createdWindow.tabs[0]);
       });
     }
   };
 }());