Reduce platform/heap/ wtf includes.

Source/platform/heap/Visitor.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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 22 matching lines @@
 
 #include "platform/PlatformExport.h"
 #include "platform/heap/StackFrameDepth.h"
 #include "platform/heap/ThreadState.h"
 #include "wtf/Assertions.h"
 #include "wtf/Atomics.h"
 #include "wtf/Deque.h"
 #include "wtf/Forward.h"
 #include "wtf/HashMap.h"
 #include "wtf/HashTraits.h"
+#include "wtf/TypeTraits.h"
+#if ENABLE(GC_PROFILING)
 #include "wtf/InstanceCounter.h"
-#include "wtf/OwnPtr.h"
-#include "wtf/RefPtr.h"
-#include "wtf/TypeTraits.h"
-#include "wtf/WeakPtr.h"
-#if ENABLE(GC_PROFILING)
 #include "wtf/text/WTFString.h"
 #endif
 
-#if ENABLE(ASSERT)
-#define DEBUG_ONLY(x) x
-#else
-#define DEBUG_ONLY(x)
-#endif
-
 namespace blink {
 
 template<typename T> class GarbageCollected;
 template<typename T> class GarbageCollectedFinalized;
 class GarbageCollectedMixin;
 class HeapObjectHeader;
 class InlinedGlobalMarkingVisitor;
 template<typename T> class Member;
 template<typename T> class WeakMember;
 class Visitor;
@@ skipping 32 matching lines @@
     bool m_nonTrivialFinalizer;
     bool m_hasVTable;
 #if ENABLE(GC_PROFILING)
     // |m_className| is held as a reference to prevent dtor being called at exit.
     const String& m_className;
 #endif
 };
 
 #if ENABLE(ASSERT)
 PLATFORM_EXPORT void assertObjectHasGCInfo(const void*, size_t gcInfoIndex);
-
 #endif
 
-
 // The FinalizerTraitImpl specifies how to finalize objects. Object
 // that inherit from GarbageCollectedFinalized are finalized by
 // calling their 'finalize' method which by default will call the
 // destructor on the object.
 template<typename T, bool isGarbageCollectedFinalized>
 struct FinalizerTraitImpl;
 
 template<typename T>
 struct FinalizerTraitImpl<T, true> {
     static void finalize(void* obj) { static_cast<T*>(obj)->finalizeGarbageCollectedObject(); };
@@ skipping 889 matching lines @@
 };
 
 template<typename T>
 struct GCInfoTrait {
     static size_t index()
     {
         return GCInfoAtBase<typename GetGarbageCollectedBase<T>::type>::index();
     }
 };
 
-}
+} // namespace blink
 
-#endif
+#endif // Visitor_h