media: Cleanup class/struct forward declarations

media/gpu/ipc/service/media_gpu_channel.h

 // Copyright 2016 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 MEDIA_GPU_IPC_SERVICE_MEDIA_GPU_CHANNEL_H_
 #define MEDIA_GPU_IPC_SERVICE_MEDIA_GPU_CHANNEL_H_
 
 #include <memory>
 
 #include "ipc/ipc_listener.h"
 #include "ipc/ipc_sender.h"
 #include "media/gpu/ipc/service/gpu_jpeg_decode_accelerator.h"
 #include "media/video/video_decode_accelerator.h"
 
 namespace media {
 struct CreateVideoEncoderParams;
 }
 
 namespace gpu {
 class GpuChannel;
-class GpuCommandBufferStub;
 }
 
 namespace media {
 
 class MediaGpuChannelDispatchHelper;
 
 class MediaGpuChannel : public IPC::Listener, public IPC::Sender {
  public:
   explicit MediaGpuChannel(gpu::GpuChannel* channel);
   ~MediaGpuChannel() override;
@@ skipping 18 matching lines @@
                             IPC::Message* reply_message);
 
   gpu::GpuChannel* const channel_;
   std::unique_ptr<GpuJpegDecodeAccelerator> jpeg_decoder_;
   DISALLOW_COPY_AND_ASSIGN(MediaGpuChannel);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_GPU_IPC_SERVICE_MEDIA_GPU_CHANNEL_H_