Add template parameter to ElementTraversal to iterate over Elements of a specific type

Source/core/dom/TreeWalker.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2000 Frederik Holljen (frederik.holljen@hig.no)
  * Copyright (C) 2001 Peter Kelly (pmk@post.com)
  * Copyright (C) 2006 Samuel Weinig (sam.weinig@gmail.com)
  * Copyright (C) 2004, 2008 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
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Library General Public License for more details.
  *
  * You should have received a copy of the GNU Library General Public License
  * along with this library; see the file COPYING.LIB.  If not, write to
  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  *
  */
 
 #ifndef TreeWalker_h
 #define TreeWalker_h
 
 #include "bindings/v8/ScriptWrappable.h"
 #include "core/dom/NodeFilter.h"
-#include "core/dom/Traversal.h"
+#include "core/dom/NodeIteratorBase.h"
 #include "wtf/PassRefPtr.h"
 #include "wtf/RefCounted.h"
 
 namespace WebCore {
 
 class ExceptionState;
 
-class TreeWalker : public ScriptWrappable, public RefCounted<TreeWalker>, public Traversal {
+class TreeWalker : public ScriptWrappable, public RefCounted<TreeWalker>, public NodeIteratorBase {
 public:
     static PassRefPtr<TreeWalker> create(PassRefPtr<Node> rootNode, unsigned whatToShow, PassRefPtr<NodeFilter> filter)
     {
         return adoptRef(new TreeWalker(rootNode, whatToShow, filter));
     }
 
     Node* currentNode() const { return m_current.get(); }
     void setCurrentNode(PassRefPtr<Node>, ExceptionState&);
 
     Node* parentNode(ScriptState*);
     Node* firstChild(ScriptState*);
     Node* lastChild(ScriptState*);
     Node* previousSibling(ScriptState*);
     Node* nextSibling(ScriptState*);
     Node* previousNode(ScriptState*);
     Node* nextNode(ScriptState*);
 
 private:
     TreeWalker(PassRefPtr<Node>, unsigned whatToShow, PassRefPtr<NodeFilter>);
 
     Node* setCurrent(PassRefPtr<Node>);
 
     RefPtr<Node> m_current;
 };
 
 } // namespace WebCore
 
 #endif // TreeWalker_h