core: Include wtf files using "wtf/foo.h" form.

Source/core/xml/XPathUtil.h

 /*
  * Copyright 2005 Frerich Raabe <raabe@kde.org>
  * Copyright (C) 2006 Apple Computer, Inc.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #ifndef XPathUtil_h
 #define XPathUtil_h
 
-#include <wtf/Forward.h>
-#include <wtf/Vector.h>
+#include "wtf/Forward.h"
+#include "wtf/Vector.h"
 
 namespace WebCore {
 
     class Node;
 
     namespace XPath {
 
         /* @return whether the given node is the root node */
         bool isRootDomNode(Node*);
 
         /* @return the 'string-value' of the given node as specified by http://www.w3.org/TR/xpath */
         String stringValue(Node*);
 
         /* @return whether the given node is a valid context node */
         bool isValidContextNode(Node*);
 
     }
 
 }
 
 #endif // XPath_Util_H