ppapi: Cleanup class/struct forward declarations

ppapi/thunk/ppb_instance_api.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_THUNK_INSTANCE_API_H_
 #define PPAPI_THUNK_INSTANCE_API_H_
 
 #include <stdint.h>
 
 #include "base/memory/ref_counted.h"
@@ skipping 25 matching lines @@
 struct PPP_MessageHandler_0_2;
 
 namespace ppapi {
 
 class Resource;
 class TrackedCallback;
 struct ViewData;
 
 namespace thunk {
 
-class PPB_Flash_API;
-
 class PPB_Instance_API {
  public:
   virtual ~PPB_Instance_API() {}
 
   virtual PP_Bool BindGraphics(PP_Instance instance, PP_Resource device) = 0;
   virtual PP_Bool IsFullFrame(PP_Instance instance) = 0;
 
   // Unexposed PPAPI functions for proxying.
   // Returns the internal view data struct.
   virtual const ViewData* GetViewData(PP_Instance instance) = 0;
@@ skipping 155 matching lines @@
                                       PP_URLComponents_Dev* components) = 0;
 #endif  // !defined(OS_NACL)
 
   static const ApiID kApiID = API_ID_PPB_INSTANCE;
 };
 
 }  // namespace thunk
 }  // namespace ppapi
 
 #endif  // PPAPI_THUNK_INSTANCE_API_H_