blink: Cleanup class forward declarations

third_party/WebKit/Source/platform/heap/ThreadState.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 39 matching lines @@
 namespace v8 {
 class Isolate;
 };
 
 namespace blink {
 
 class BasePage;
 class CallbackStack;
 struct GCInfo;
 class GarbageCollectedMixinConstructorMarker;
-class HeapObjectHeader;
 class PersistentNode;
 class PersistentRegion;
 class BaseArena;
 class SafePointAwareMutexLocker;
 class SafePointBarrier;
 class ThreadHeap;
 class ThreadState;
 class Visitor;
 
 // Declare that a class has a pre-finalizer. The pre-finalizer is called
@@ skipping 682 matching lines @@
 class ThreadStateFor<AnyThread> {
   STATIC_ONLY(ThreadStateFor);
 
  public:
   static ThreadState* state() { return ThreadState::current(); }
 };
 
 }  // namespace blink
 
 #endif  // ThreadState_h