Remove unnecessary includes from dom.

third_party/WebKit/Source/core/dom/ElementDataCache.h

 /*
  * Copyright (C) 2012, 2013 Apple Inc. All Rights Reserved.
  *
  * 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
@@ skipping 11 matching lines @@
  * (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 ElementDataCache_h
 #define ElementDataCache_h
 
 #include "platform/heap/Handle.h"
 #include "wtf/HashMap.h"
-#include "wtf/PassOwnPtr.h"
-#include "wtf/PassRefPtr.h"
-#include "wtf/RefPtr.h"
 #include "wtf/Vector.h"
 #include "wtf/text/StringHash.h"
 
 namespace blink {
 
 class Attribute;
 class ShareableElementData;
 
 class ElementDataCache final : public GarbageCollected<ElementDataCache>  {
 public:
     static RawPtr<ElementDataCache> create() { return new ElementDataCache; }
 
     RawPtr<ShareableElementData> cachedShareableElementDataWithAttributes(const Vector<Attribute>&);
 
     DECLARE_TRACE();
 
 private:
     ElementDataCache();
 
     typedef HeapHashMap<unsigned, Member<ShareableElementData>, AlreadyHashed> ShareableElementDataCache;
     ShareableElementDataCache m_shareableElementDataCache;
 };
 
 } // namespace blink
 
 #endif