Have ScopedStyleResolver deal with ContainerNode references, not pointers

Source/core/dom/Element.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Peter Kelly (pmk@post.com)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2013 Apple Inc. All rights reserved.
  *
  * 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 783 matching lines @@
     ASSERT_WITH_SECURITY_IMPLICATION(!node || node->isElementNode());
     return static_cast<Element*>(node);
 }
 
 inline const Element* toElement(const Node* node)
 {
     ASSERT_WITH_SECURITY_IMPLICATION(!node || node->isElementNode());
     return static_cast<const Element*>(node);
 }
 
+inline const Element& toElement(const Node& node)
+{
+    ASSERT_WITH_SECURITY_IMPLICATION(node.isElementNode());
+    return static_cast<const Element&>(node);
+}
+
 // This will catch anyone doing an unnecessary cast.
 void toElement(const Element*);
 
 inline bool isDisabledFormControl(const Node* node)
 {
     return node->isElementNode() && toElement(node)->isDisabledFormControl();
 }
 
 inline bool Node::hasTagName(const QualifiedName& name) const
 {
@@ skipping 272 matching lines @@
 
 inline const Attribute* ElementData::attributeItem(unsigned index) const
 {
     RELEASE_ASSERT(index < length());
     return attributeBase() + index;
 }
 
 } // namespace
 
 #endif