blink: Cleanup class forward declarations

third_party/WebKit/Source/bindings/core/v8/DOMWrapperWorld.h

 /*
  * Copyright (C) 2009 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 37 matching lines @@
   MainWorldId = 0,
   // Embedder isolated worlds can use IDs in [1, 1<<29).
   EmbedderWorldIdLimit = (1 << 29),
   PrivateScriptIsolatedWorldId,
   IsolatedWorldIdLimit,
   WorkerWorldId,
   TestingWorldId,
 };
 
 class DOMObjectHolderBase;
-class DOMWrapperWorldVisitor;
 template <typename T>
 class DOMObjectHolder;
 
 // This class represent a collection of DOM wrappers for a specific world.
 class CORE_EXPORT DOMWrapperWorld : public RefCounted<DOMWrapperWorld> {
  public:
   static PassRefPtr<DOMWrapperWorld> create(v8::Isolate*,
                                             int worldId = -1,
                                             int extensionGroup = -1);
 
@@ skipping 77 matching lines @@
 
   const int m_worldId;
   const int m_extensionGroup;
   std::unique_ptr<DOMDataStore> m_domDataStore;
   HashSet<std::unique_ptr<DOMObjectHolderBase>> m_domObjectHolders;
 };
 
 }  // namespace blink
 
 #endif  // DOMWrapperWorld_h