Issue 1840 - Fixed memory leak caused by "forward" messages

background.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 542 matching lines @@
     case "add-sitekey":
       processKey(msg.token, sender.page, sender.frame);
       break;
     case "report-html-page":
       htmlPages.set(sender.page, null);
       refreshIconAndContextMenu(sender.page);
       break;
     case "forward":
       if (sender.page)
       {
-        sender.page.sendMessage(msg.payload, sendResponse);
-        // Return true to indicate that we want to call
-        // sendResponse asynchronously
-        return true;
+        if (msg.expectsResponse)
+        {
+          sender.page.sendMessage(msg.payload, sendResponse);
+          return true;
+        }
+
+        sender.page.sendMessage(msg.payload);
       }
       break;
   }
 });
 
 // update icon when page changes location
 ext.pages.onLoading.addListener(function(page)
 {
   page.sendMessage({type: "clickhide-deactivate"});
   refreshIconAndContextMenu(page);
 });
 
 setTimeout(function()
 {
   var notificationToShow = NotificationStorage.getNextToShow();
   if (notificationToShow)
     showNotification(notificationToShow);
 }, 3 * 60 * 1000);