media: Cleanup class/struct forward declarations

media/filters/gpu_video_decoder.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 MEDIA_FILTERS_GPU_VIDEO_DECODER_H_
 #define MEDIA_FILTERS_GPU_VIDEO_DECODER_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <list>
 #include <map>
 #include <set>
 #include <utility>
 #include <vector>
 
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "gpu/command_buffer/common/sync_token.h"
 #include "media/base/pipeline_status.h"
 #include "media/base/surface_manager.h"
 #include "media/base/video_decoder.h"
 #include "media/video/video_decode_accelerator.h"
 
 template <class T> class scoped_refptr;
 
 namespace base {
 class SharedMemory;
-class SingleThreadTaskRunner;
 }
 
 namespace gpu {
 struct SyncToken;
 }
 
 namespace media {
 
 class DecoderBuffer;
 class GpuVideoAcceleratorFactories;
@@ skipping 219 matching lines @@
   // Bound to factories_->GetMessageLoop().
   // NOTE: Weak pointers must be invalidated before all other member variables.
   base::WeakPtrFactory<GpuVideoDecoder> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(GpuVideoDecoder);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_FILTERS_GPU_VIDEO_DECODER_H_