Refactor video capture to new design

ppapi/thunk/ppb_buffer_api.h

 // Copyright (c) 2011 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_PPB_BUFFER_API_H_
 #define PPAPI_THUNK_PPB_BUFFER_API_H_
 
 #include "ppapi/c/pp_bool.h"
 #include "ppapi/c/pp_stdint.h"
+#include "ppapi/thunk/ppapi_thunk_export.h"
 
 namespace ppapi {
 namespace thunk {
 
-class PPB_Buffer_API {
+class PPAPI_THUNK_EXPORT PPB_Buffer_API {
  public:
   virtual ~PPB_Buffer_API() {}
 
   virtual PP_Bool Describe(uint32_t* size_in_bytes) = 0;
   virtual PP_Bool IsMapped() = 0;
   virtual void* Map() = 0;
   virtual void Unmap() = 0;
 };
 
 }  // namespace thunk
 }  // namespace ppapi
 
 #endif  // PPAPI_THUNK_PPB_BUFFER_API_H_