Issue 1663 - Emulate background page and implement proper message responder

background.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
@@ skipping 138 matching lines @@
     }
     else
       return undefined;
   }
 
   global.openOptions = function()
   {
     window.open("http://example.com/options.html", "_blank");
   };
 
+  global.Services = {
+    vc: {
+      compare: function(v1, v2)
+      {
+        return parseFloat(v1) - parseFloat(v2);
+      }
+    }
+  };
+
   var issues = {seenDataCorruption: false, filterlistsReinitialized: false};
   updateFromURL(issues);
   global.seenDataCorruption = issues.seenDataCorruption;
   global.filterlistsReinitialized = issues.filterlistsReinitialized;
 })(this);