blink: Cleanup class/struct forward declarations

third_party/WebKit/Source/platform/heap/WrapperVisitor.h

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef WrapperVisitor_h
 #define WrapperVisitor_h
 
 #include "platform/PlatformExport.h"
 #include "wtf/Allocator.h"
 
 namespace v8 {
 class Value;
-class Object;
 template <class T>
 class PersistentBase;
 }
 
 namespace blink {
 
 template <typename T>
 class TraceTrait;
 template <typename T>
 class Member;
@@ skipping 133 matching lines @@
   virtual void markWrappersInAllWorlds(const void*) const = 0;
   virtual void pushToMarkingDeque(
       void (*traceWrappersCallback)(const WrapperVisitor*, const void*),
       HeapObjectHeader* (*heapObjectHeaderCallback)(const void*),
       const void*) const = 0;
 };
 
 }  // namespace blink
 
 #endif  // WrapperVisitor_h