Remove the concept of document.documentElement

sky/engine/core/css/resolver/SharedStyleFinder.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 2004-2005 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2006, 2007 Nicholas Shanks (webkit@nickshanks.com)
  * Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Alexey Proskuryakov <ap@webkit.org>
  * Copyright (C) 2007, 2008 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (c) 2011, Code Aurora Forum. All rights reserved.
  * Copyright (C) Research In Motion Limited 2011. All rights reserved.
@@ skipping 123 matching lines @@
         return false;
     if (!sharingCandidateCanShareHostStyles(candidate))
         return false;
     if (!candidate.treeScope().hasSameStyles(element().treeScope()))
         return false;
     return true;
 }
 
 bool SharedStyleFinder::documentContainsValidCandidate() const
 {
-    for (Element* element = document().documentElement(); element; element = ElementTraversal::next(*element)) {
+    for (Element* element = ElementTraversal::firstChild(document()); element; element = ElementTraversal::next(*element)) {
         if (element->supportsStyleSharing() && canShareStyleWithElement(*element))
             return true;
     }
     return false;
 }
 
 inline Element* SharedStyleFinder::findElementForStyleSharing() const
 {
     StyleSharingList& styleSharingList = m_styleResolver.styleSharingList();
     for (StyleSharingList::iterator it = styleSharingList.begin(); it != styleSharingList.end(); ++it) {
@@ skipping 34 matching lines @@
             INCREMENT_STYLE_STATS_COUNTER(m_styleResolver, sharedStyleMissed);
         return 0;
     }
 
     INCREMENT_STYLE_STATS_COUNTER(m_styleResolver, sharedStyleFound);
 
     return shareElement->renderStyle();
 }
 
 }