Use Traversal<>::firstChild() instead of firstWithin() when iterating over children

Source/core/dom/Document.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2008, 2009, 2011, 2012 Google Inc. All rights reserved.
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) Research In Motion Limited 2010-2011. All rights reserved.
@@ skipping 2380 matching lines @@
     setReadyState(Loading);
 
     return m_parser;
 }
 
 HTMLElement* Document::body() const
 {
     if (!documentElement())
         return 0;
 
-    for (HTMLElement* child = Traversal<HTMLElement>::firstWithin(*documentElement()); child; child = Traversal<HTMLElement>::nextSibling(*child)) {
+    for (HTMLElement* child = Traversal<HTMLElement>::firstChild(*documentElement()); child; child = Traversal<HTMLElement>::nextSibling(*child)) {
         if (isHTMLFrameSetElement(*child) || isHTMLBodyElement(*child))
             return child;
     }
 
     return 0;
 }
 
 void Document::setBody(PassRefPtrWillBeRawPtr<HTMLElement> prpNewBody, ExceptionState& exceptionState)
 {
     RefPtrWillBeRawPtr<HTMLElement> newBody = prpNewBody;
@@ skipping 3475 matching lines @@
 using namespace blink;
 void showLiveDocumentInstances()
 {
     WeakDocumentSet& set = liveDocumentSet();
     fprintf(stderr, "There are %u documents currently alive:\n", set.size());
     for (WeakDocumentSet::const_iterator it = set.begin(); it != set.end(); ++it) {
         fprintf(stderr, "- Document %p URL: %s\n", *it, (*it)->url().string().utf8().data());
     }
 }
 #endif