blink: Cleanup core class forward declarations

third_party/WebKit/Source/core/observer/ResizeObserverEntry.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 ResizeObserverEntry_h
 #define ResizeObserverEntry_h
 
 #include "bindings/core/v8/ScriptWrappable.h"
 #include "platform/heap/Handle.h"
 
 namespace blink {
 
 class Element;
 class ClientRect;
 class LayoutRect;
-class LayoutSize;
 
 class ResizeObserverEntry final : public GarbageCollected<ResizeObserverEntry>,
                                   public ScriptWrappable {
   DEFINE_WRAPPERTYPEINFO();
 
  public:
   ResizeObserverEntry(Element* target, const LayoutRect& contentRect);
 
   Element* target() const { return m_target; }
   // FIXME(atotic): should return DOMRectReadOnly once https://crbug.com/388780
   // lands
   ClientRect* contentRect() const { return m_contentRect; }
 
   DECLARE_VIRTUAL_TRACE();
 
  private:
   Member<Element> m_target;
   Member<ClientRect> m_contentRect;
 };
 
 }  // namespace blink
 
 #endif  // ResizeObserverEntry_h