Have Node::diff() take a Document reference in argument

Source/core/dom/Node.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (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 149 matching lines @@
 
     // All Nodes are placed in their own heap partition for security.
     // See http://crbug.com/246860 for detail.
     void* operator new(size_t);
     void operator delete(void*);
 
     static bool isSupported(const String& feature, const String& version);
     static void dumpStatistics();
 
     enum StyleChange { NoChange, NoInherit, Inherit, Force, Reattach };
-    static StyleChange diff(const RenderStyle*, const RenderStyle*, Document*);
+    static StyleChange diff(const RenderStyle*, const RenderStyle*, const Document&);
 
     virtual ~Node();
     void willBeDeletedFrom(Document*);
 
     // DOM methods & attributes for Node
 
     bool hasTagName(const QualifiedName&) const;
     bool hasLocalName(const AtomicString&) const;
     virtual String nodeName() const = 0;
     virtual String nodeValue() const;
@@ skipping 762 matching lines @@
 
 } //namespace
 
 #ifndef NDEBUG
 // Outside the WebCore namespace for ease of invocation from gdb.
 void showTree(const WebCore::Node*);
 void showNodePath(const WebCore::Node*);
 #endif
 
 #endif