Simplified and removed memory leaks from code dealing with frames on Chrome

popupBlocker.js

 /*
  * This file is part of Adblock Plus <http://adblockplus.org/>,
  * Copyright (C) 2006-2013 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/>.
  */
 
 if (require("info").platform == "chromium" && "webNavigation" in chrome)
 {
   var tabsLoading = {};
 
   chrome.webNavigation.onCreatedNavigationTarget.addListener(function(details)
   {
     var sourcePage = new ext.Page({id: details.sourceTabId});
-    var sourceFrame = new ext.Frame({frameId: details.sourceFrameId, tabId: details.sourceTabId});
+    var sourceFrame = ext.getFrame(details.sourceTabId, details.sourceFrameId);
 
-    if (isFrameWhitelisted(sourcePage, sourceFrame))
+    if (!sourceFrame || isFrameWhitelisted(sourcePage, sourceFrame))
       return;
 
     var openerUrl = sourceFrame.url;
     if (!openerUrl)
     {
       // We don't know the opener tab
       return;
     }
     tabsLoading[details.tabId] = openerUrl;
 
@@ skipping 18 matching lines @@
 
 function checkPotentialPopup(tabId, url, opener)
 {
   var requestHost = extractHostFromURL(url);
   var documentHost = extractHostFromURL(opener);
   var thirdParty = isThirdParty(requestHost, documentHost);
   var filter = defaultMatcher.matchesAny(url || "about:blank", "POPUP", documentHost, thirdParty);
   if (filter instanceof BlockingFilter)
     chrome.tabs.remove(tabId);
 }