Remove unnecessary includes from dom.

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

 /*
  * Copyright (C) 2013 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 18 matching lines @@
  */
 
 #ifndef CustomElementRegistrationContext_h
 #define CustomElementRegistrationContext_h
 
 #include "core/dom/QualifiedName.h"
 #include "core/dom/custom/CustomElementDescriptor.h"
 #include "core/dom/custom/CustomElementRegistry.h"
 #include "core/dom/custom/CustomElementUpgradeCandidateMap.h"
 #include "platform/heap/Handle.h"
-#include "wtf/HashMap.h"
-#include "wtf/PassOwnPtr.h"
-#include "wtf/PassRefPtr.h"
 #include "wtf/text/AtomicString.h"
 
 namespace blink {
 
 class CustomElementRegistrationContext final : public GarbageCollectedFinalized<CustomElementRegistrationContext> {
 public:
     static RawPtr<CustomElementRegistrationContext> create()
     {
         return new CustomElementRegistrationContext();
     }
@@ skipping 24 matching lines @@
     CustomElementRegistry m_registry;
 
     // Element creation
     Member<CustomElementUpgradeCandidateMap> m_candidates;
 };
 
 } // namespace blink
 
 #endif // CustomElementRegistrationContext_h