Issue 3251 - Simplify messaging from child scripts to parent

lib/utils.js

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-2015 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 545 matching lines @@
 
       if (callbackID)
       {
         let target = message.target.QueryInterface(Ci.nsIMessageSender);
         target.sendAsyncMessage("AdblockPlus:Response", {
           callbackID,
           response
         });
       }
       else
-        return JSON.stringify(response);
+        return response;
     };
     messageManager.addMessageListener(messageName, wrapper);
     onShutdown.add(() => messageManager.removeMessageListener(messageName, wrapper));
   }
 };
 
 /**
  * A cache with a fixed capacity, newer entries replace entries that have been
  * stored first.
  * @constructor
@@ skipping 243 matching lines @@
     Cu.reportError(e);
     // Expected, ctypes isn't supported in Gecko 1.9.2
     return null;
   }
 });
 
 if ("@mozilla.org/messenger/headerparser;1" in Cc)
   XPCOMUtils.defineLazyServiceGetter(Utils, "headerParser", "@mozilla.org/messenger/headerparser;1", "nsIMsgHeaderParser");
 else
   Utils.headerParser = null;