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      1 // Copyright 2013 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #ifndef CONTENT_RENDERER_MEDIA_MEDIA_STREAM_VIDEO_TRACK_H_
      6 #define CONTENT_RENDERER_MEDIA_MEDIA_STREAM_VIDEO_TRACK_H_
      7 
      8 #include <vector>
      9 
     10 #include "base/compiler_specific.h"
     11 #include "base/gtest_prod_util.h"
     12 #include "base/memory/scoped_vector.h"
     13 #include "base/threading/thread_checker.h"
     14 #include "content/common/content_export.h"
     15 #include "content/public/renderer/media_stream_video_sink.h"
     16 #include "content/renderer/media/media_stream_track.h"
     17 #include "content/renderer/media/media_stream_video_source.h"
     18 
     19 namespace content {
     20 
     21 // MediaStreamVideoTrack is a video specific representation of a
     22 // blink::WebMediaStreamTrack in content. It is owned by the blink object
     23 // and can be retrieved from a blink object using
     24 // WebMediaStreamTrack::extraData() or MediaStreamVideoTrack::GetVideoTrack.
     25 class CONTENT_EXPORT MediaStreamVideoTrack : public MediaStreamTrack {
     26  public:
     27   // Help method to create a blink::WebMediaStreamTrack and a
     28   // MediaStreamVideoTrack instance. The MediaStreamVideoTrack object is owned
     29   // by the blink object in its WebMediaStreamTrack::ExtraData member.
     30   // |callback| is triggered if the track is added to the source
     31   // successfully and will receive video frames that match |constraints|
     32   // or if the source fail to provide video frames.
     33   // If |enabled| is true, sinks added to the track will
     34   // receive video frames when the source deliver frames to the track.
     35   static blink::WebMediaStreamTrack CreateVideoTrack(
     36       MediaStreamVideoSource* source,
     37       const blink::WebMediaConstraints& constraints,
     38       const MediaStreamVideoSource::ConstraintsCallback& callback,
     39       bool enabled);
     40 
     41   static MediaStreamVideoTrack* GetVideoTrack(
     42       const blink::WebMediaStreamTrack& track);
     43 
     44   // Constructor for video tracks.
     45   MediaStreamVideoTrack(
     46       MediaStreamVideoSource* source,
     47       const blink::WebMediaConstraints& constraints,
     48       const MediaStreamVideoSource::ConstraintsCallback& callback,
     49       bool enabled);
     50   virtual ~MediaStreamVideoTrack();
     51 
     52   virtual void SetEnabled(bool enabled) OVERRIDE;
     53 
     54   virtual void Stop() OVERRIDE;
     55 
     56   void OnReadyStateChanged(blink::WebMediaStreamSource::ReadyState state);
     57 
     58   const blink::WebMediaConstraints& constraints() const {
     59     return constraints_;
     60   }
     61 
     62  protected:
     63   // Used to DCHECK that we are called on the correct thread.
     64   base::ThreadChecker thread_checker_;
     65 
     66  private:
     67   // MediaStreamVideoSink is a friend to allow it to call AddSink() and
     68   // RemoveSink().
     69   friend class MediaStreamVideoSink;
     70   FRIEND_TEST_ALL_PREFIXES(MediaStreamRemoteVideoSourceTest, StartTrack);
     71   FRIEND_TEST_ALL_PREFIXES(MediaStreamRemoteVideoSourceTest, RemoteTrackStop);
     72   FRIEND_TEST_ALL_PREFIXES(VideoDestinationHandlerTest, PutFrame);
     73 
     74   // Add |sink| to receive state changes on the main render thread and video
     75   // frames in the |callback| method on the IO-thread.
     76   // |callback| will be reset on the render thread.
     77   // These two methods are private such that no subclass can intercept and
     78   // store the callback. This is important to ensure that we can release
     79   // the callback on render thread without reference to it on the IO-thread.
     80   void AddSink(MediaStreamVideoSink* sink,
     81                const VideoCaptureDeliverFrameCB& callback);
     82   void RemoveSink(MediaStreamVideoSink* sink);
     83 
     84   std::vector<MediaStreamVideoSink*> sinks_;
     85 
     86   // |FrameDeliverer| is an internal helper object used for delivering video
     87   // frames on the IO-thread using callbacks to all registered tracks.
     88   class FrameDeliverer;
     89   scoped_refptr<FrameDeliverer> frame_deliverer_;
     90 
     91   blink::WebMediaConstraints constraints_;
     92 
     93   // Weak ref to the source this tracks is connected to.  |source_| is owned
     94   // by the blink::WebMediaStreamSource and is guaranteed to outlive the
     95   // track.
     96   MediaStreamVideoSource* source_;
     97 
     98   DISALLOW_COPY_AND_ASSIGN(MediaStreamVideoTrack);
     99 };
    100 
    101 }  // namespace content
    102 
    103 #endif  // CONTENT_RENDERER_MEDIA_MEDIA_STREAM_VIDEO_TRACK_H_
    104