Clean up forward declarations in WebKit/Source

Source/core/xml/XMLSerializer.h

 /*
  *  Copyright (C) 2003, 2006 Apple Computer, Inc.
  *  Copyright (C) 2006 Samuel Weinig (sam@webkit.org)
  *
  *  This library is free software; you can redistribute it and/or
  *  modify it under the terms of the GNU Lesser General Public
  *  License as published by the Free Software Foundation; either
  *  version 2 of the License, or (at your option) any later version.
  *
  *  This library is distributed in the hope that it will be useful,
@@ skipping 10 matching lines @@
 #define XMLSerializer_h
 
 #include "bindings/core/v8/ScriptWrappable.h"
 #include "platform/heap/Handle.h"
 #include "wtf/Forward.h"
 #include "wtf/PassRefPtr.h"
 #include "wtf/RefCounted.h"
 
 namespace blink {
 
-class ExceptionState;
 class Node;
 
 class XMLSerializer final : public RefCountedWillBeGarbageCollected<XMLSerializer>, public ScriptWrappable {
     DEFINE_WRAPPERTYPEINFO();
 public:
     static PassRefPtrWillBeRawPtr<XMLSerializer> create()
     {
         return adoptRefWillBeNoop(new XMLSerializer);
     }
 
     String serializeToString(Node*);
 
     void trace(Visitor*) { }
 
 private:
     XMLSerializer() { }
 };
 
 } // namespace blink
 
 #endif // XMLSerializer_h