ppapi: Cleanup class/struct forward declarations

ppapi/proxy/video_encoder_resource.h

 // Copyright 2015 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_PROXY_VIDEO_ENCODER_RESOURCE_H_
 #define PPAPI_PROXY_VIDEO_ENCODER_RESOURCE_H_
 
 #include <stdint.h>
 
 #include <deque>
@@ skipping 11 matching lines @@
 namespace base {
 class SharedMemory;
 }
 
 namespace ppapi {
 
 class TrackedCallback;
 
 namespace proxy {
 
-class SerializedHandle;
 class VideoFrameResource;
 
 class PPAPI_PROXY_EXPORT VideoEncoderResource
     : public PluginResource,
       public thunk::PPB_VideoEncoder_API,
       public ppapi::MediaStreamBufferManager::Delegate {
  public:
   VideoEncoderResource(Connection connection, PP_Instance instance);
   ~VideoEncoderResource() override;
 
@@ skipping 116 matching lines @@
   scoped_refptr<TrackedCallback> get_bitstream_buffer_callback_;
   PP_BitstreamBuffer* get_bitstream_buffer_data_;
 
   DISALLOW_COPY_AND_ASSIGN(VideoEncoderResource);
 };
 
 }  // namespace proxy
 }  // namespace ppapi
 
 #endif  // PPAPI_PROXY_VIDEO_ENCODER_RESOURCE_H_