ppapi: Cleanup class/struct forward declarations

ppapi/cpp/instance.h

 // Copyright (c) 2012 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 PPAPI_CPP_INSTANCE_H_
 #define PPAPI_CPP_INSTANCE_H_
 
 /// @file
 /// This file defines the C++ wrapper for an instance.
 
 #include <map>
 #include <string>
 
 #include "ppapi/c/pp_instance.h"
 #include "ppapi/c/pp_resource.h"
 #include "ppapi/c/pp_stdint.h"
 #include "ppapi/c/ppb_console.h"
 #include "ppapi/cpp/instance_handle.h"
 #include "ppapi/cpp/view.h"
 
 // Windows defines 'PostMessage', so we have to undef it.
 #ifdef PostMessage
 #undef PostMessage
 #endif
 
-struct PP_InputEvent;
-
 /// The C++ interface to the Pepper API.
 namespace pp {
 
 class Compositor;
 class Graphics2D;
 class Graphics3D;
 class InputEvent;
 class InstanceHandle;
 class MessageHandler;
 class MessageLoop;
@@ skipping 594 matching lines @@
  private:
   PP_Instance pp_instance_;
 
   typedef std::map<std::string, void*> InterfaceNameToObjectMap;
   InterfaceNameToObjectMap interface_name_to_objects_;
 };
 
 }  // namespace pp
 
 #endif  // PPAPI_CPP_INSTANCE_H_