Have DOMWindow deal with references instead of pointers when possible

Source/core/fetch/ResourceFetcher.cpp

 /*
     Copyright (C) 1998 Lars Knoll (knoll@mpi-hd.mpg.de)
     Copyright (C) 2001 Dirk Mueller (mueller@kde.org)
     Copyright (C) 2002 Waldo Bastian (bastian@kde.org)
     Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
     Copyright (C) 2009 Torch Mobile Inc. http://www.torchmobile.com/
 
     This library is free software; you can redistribute it and/or
     modify it under the terms of the GNU Library General Public
     License as published by the Free Software Foundation; either
@@ skipping 162 matching lines @@
         info->clearLoadTimings();
     info->setLoadFinishTime(resource->loadFinishTime());
 }
 
 static void reportResourceTiming(ResourceTimingInfo* info, Document* initiatorDocument, bool isMainResource)
 {
     if (initiatorDocument && isMainResource)
         initiatorDocument = initiatorDocument->parentDocument();
     if (!initiatorDocument || !initiatorDocument->loader())
         return;
-    if (DOMWindow* initiatorWindow = initiatorDocument->domWindow()) {
-        if (Performance* performance = initiatorWindow->performance())
-            performance->addResourceTiming(*info, initiatorDocument);
-    }
+    if (DOMWindow* initiatorWindow = initiatorDocument->domWindow())
+        initiatorWindow->performance().addResourceTiming(*info, initiatorDocument);
 }
 
 static ResourceRequest::TargetType requestTargetType(const ResourceFetcher* fetcher, const ResourceRequest& request, Resource::Type type)
 {
     switch (type) {
     case Resource::MainResource:
         if (fetcher->frame()->tree().parent())
             return ResourceRequest::TargetIsSubframe;
         return ResourceRequest::TargetIsMainFrame;
     case Resource::XSLStyleSheet:
@@ skipping 1204 matching lines @@
     case Revalidate:
         ++m_revalidateCount;
         return;
     case Use:
         ++m_useCount;
         return;
     }
 }
 
 }