Clean up forward declarations in Source/web

Source/web/WebDevToolsAgentPrivate.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 20 matching lines @@
 #ifndef WebDevToolsAgentPrivate_h
 #define WebDevToolsAgentPrivate_h
 
 #include "public/web/WebDevToolsAgent.h"
 
 namespace blink {
 
 class Page;
 class WebLocalFrameImpl;
 class WebInputEvent;
-struct WebSize;
 
 class WebDevToolsAgentPrivate : public WebDevToolsAgent {
 public:
 
     // Notification from FrameLoaderClientImpl:
     // New context has been created for a given world in given frame. Any
     // processing hat needs to happen before the first script is evaluated
     // in this context should be done here.
     virtual void didCreateScriptContext(WebLocalFrameImpl*, int worldId) = 0;
 
     // DevTools may handle input event from WebViewImpl.
     virtual bool handleInputEvent(Page*, const WebInputEvent&) = 0;
 
     // Notification from WebViewImpl after layout.
     virtual void didLayout() = 0;
 };
 
 } // namespace blink
 
 #endif