Remove unnecessary includes from dom.

third_party/WebKit/Source/core/dom/custom/CustomElementRegistry.h

 /*
  * Copyright (C) 2012 Google 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
@@ skipping 19 matching lines @@
 
 #ifndef CustomElementRegistry_h
 #define CustomElementRegistry_h
 
 #include "core/dom/custom/CustomElement.h"
 #include "core/dom/custom/CustomElementDefinition.h"
 #include "core/dom/custom/CustomElementDescriptor.h"
 #include "core/dom/custom/CustomElementDescriptorHash.h"
 #include "wtf/HashMap.h"
 #include "wtf/HashSet.h"
-#include "wtf/RefPtr.h"
 #include "wtf/text/AtomicString.h"
 #include "wtf/text/AtomicStringHash.h"
 
 namespace blink {
 
 class CustomElementConstructorBuilder;
 class ExceptionState;
 
 class CustomElementRegistry final {
     WTF_MAKE_NONCOPYABLE(CustomElementRegistry);
@@ skipping 13 matching lines @@
 private:
     typedef HeapHashMap<CustomElementDescriptor, Member<CustomElementDefinition>> DefinitionMap;
     DefinitionMap m_definitions;
     HashSet<AtomicString> m_registeredTypeNames;
     bool m_documentWasDetached;
 };
 
 } // namespace blink
 
 #endif // CustomElementRegistry_h