Clean forward declaration in public

Source/web/tests/FakeWebPlugin.h

 /*
  * Copyright (C) 2012 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 23 matching lines @@
 #include "public/web/WebPlugin.h"
 
 namespace blink {
 
 class WebDragData;
 class WebFrame;
 class WebInputEvent;
 class WebPluginContainer;
 class WebURL;
 class WebURLResponse;
+struct WebPluginParams;
 
 class FakeWebPlugin : public WebPlugin {
 public:
     FakeWebPlugin(WebFrame*, const WebPluginParams&);
 
     // WebPlugin methods:
     virtual bool initialize(WebPluginContainer*) override;
     virtual void destroy() override;
     virtual NPObject* scriptableObject() override { return 0; }
     virtual bool canProcessDrag() const override { return false; }
@@ skipping 16 matching lines @@
     virtual ~FakeWebPlugin();
 
 private:
     WebFrame* m_frame;
     WebPluginContainer* m_container;
 };
 
 } // namespace blink
 
 #endif // FakeWebPlugin_h