[WIP] Proxy RtcVideoDecoder calls to a media::VideoDecoder.

content/renderer/media/gpu/rtc_video_decoder_factory.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 CONTENT_RENDERER_MEDIA_GPU_RTC_VIDEO_DECODER_FACTORY_H_
 #define CONTENT_RENDERER_MEDIA_GPU_RTC_VIDEO_DECODER_FACTORY_H_
 
+#include <memory>
+
+#include "base/callback.h"
 #include "base/macros.h"
-#include "base/threading/thread.h"
+#include "base/single_thread_task_runner.h"
 #include "content/common/content_export.h"
 #include "third_party/webrtc/media/engine/webrtcvideodecoderfactory.h"
 #include "third_party/webrtc/modules/video_coding/include/video_codec_interface.h"
 
 namespace webrtc {
 class VideoDecoder;
 }  // namespace webrtc
 
 namespace media {
-class GpuVideoAcceleratorFactories;
+class VideoDecoder;
 }  // namespace media
 
 namespace content {
 
 // TODO(wuchengli): add unittest.
 class CONTENT_EXPORT RTCVideoDecoderFactory
     : NON_EXPORTED_BASE(public cricket::WebRtcVideoDecoderFactory) {
  public:
-  explicit RTCVideoDecoderFactory(
-      media::GpuVideoAcceleratorFactories* gpu_factories);
+  using CreateVideoDecoderCB =
+      base::Callback<std::unique_ptr<media::VideoDecoder>()>;
+
+  // |create_video_decoder_cb| will be passed to the created RtcVideoDecoder,
+  // which will run it on |decoder_task_runner|'s thread. All calls made on
+  // RtcVideoDecoder will be proxied on this thread to the media::VideoDecoder
+  // returned by this callback. For more information, see RtcVideoDeocder.
+  RTCVideoDecoderFactory(
+      const CreateVideoDecoderCB& create_video_decoder_cb,
+      const scoped_refptr<base::SingleThreadTaskRunner>& decoder_task_runner);
   ~RTCVideoDecoderFactory() override;
 
   // Runs on Chrome_libJingle_WorkerThread. The child thread is blocked while
   // this runs.
   webrtc::VideoDecoder* CreateVideoDecoder(
       webrtc::VideoCodecType type) override;
 
   // Runs on Chrome_libJingle_WorkerThread. The child thread is blocked while
   // this runs.
   void DestroyVideoDecoder(webrtc::VideoDecoder* decoder) override;
 
  private:
-  media::GpuVideoAcceleratorFactories* gpu_factories_;
+  // These are cached and passed into RtcVideoDecoder::Create().
+  const CreateVideoDecoderCB create_video_decoder_cb_;
+  const scoped_refptr<base::SingleThreadTaskRunner> decoder_task_runner_;
 
   DISALLOW_COPY_AND_ASSIGN(RTCVideoDecoderFactory);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_MEDIA_GPU_RTC_VIDEO_DECODER_FACTORY_H_