media: Cleanup class/struct forward declarations

media/gpu/ipc/service/gpu_video_encode_accelerator.h

 // Copyright 2013 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_GPU_VIDEO_ENCODE_ACCELERATOR_H_
 #define MEDIA_GPU_IPC_SERVICE_GPU_VIDEO_ENCODE_ACCELERATOR_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <memory>
 #include <vector>
 
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "base/synchronization/waitable_event.h"
 #include "base/threading/thread.h"
 #include "gpu/config/gpu_info.h"
 #include "gpu/ipc/service/gpu_command_buffer_stub.h"
 #include "ipc/ipc_listener.h"
 #include "media/video/video_encode_accelerator.h"
 #include "ui/gfx/geometry/size.h"
 
 struct AcceleratedVideoEncoderMsg_Encode_Params;
 
-namespace base {
-class SharedMemory;
-}  // namespace base
-
 namespace gpu {
 struct GpuPreferences;
 }  // namespace gpu
 
 namespace media {
 
 // This class encapsulates the GPU process view of a VideoEncodeAccelerator,
 // wrapping the platform-specific VideoEncodeAccelerator instance.  It handles
 // IPC coming in from the renderer and passes it to the underlying VEA.
 class GpuVideoEncodeAccelerator
@@ skipping 130 matching lines @@
   // Weak pointer for VideoFrames that refer back to |this| on
   // |main_task_runner| or |io_task_runner_|.
   base::WeakPtrFactory<GpuVideoEncodeAccelerator> weak_this_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(GpuVideoEncodeAccelerator);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_GPU_IPC_SERVICE_GPU_VIDEO_ENCODE_ACCELERATOR_H_