Chrome MediaStream VideoTrack implementation.

content/renderer/media/media_stream_video_source.h

 // Copyright 2014 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_MEDIA_STREAM_VIDEO_SOURCE_H_
 #define CONTENT_RENDERER_MEDIA_MEDIA_STREAM_VIDEO_SOURCE_H_
 
 #include <vector>
 
 #include "base/compiler_specific.h"
 #include "content/common/content_export.h"
 #include "content/renderer/media/media_stream_dependency_factory.h"
 #include "content/renderer/media/media_stream_source.h"
+#include "content/renderer/media/media_stream_video_track.h"
 #include "media/base/video_frame.h"
 #include "media/video/capture/video_capture_types.h"
 #include "third_party/WebKit/public/platform/WebMediaConstraints.h"
 #include "third_party/WebKit/public/platform/WebMediaStreamSource.h"
 #include "third_party/WebKit/public/platform/WebMediaStreamTrack.h"
 
 namespace media {
 class VideoFrame;
 }
 
 namespace content {
 
 class MediaStreamDependencyFactory;
+class MediaStreamVideoTrack;
 class WebRtcVideoCapturerAdapter;
 
 // MediaStreamVideoSource is an interface used for sending video frames to a
 // MediaStreamVideoTrack.
 // http://dev.w3.org/2011/webrtc/editor/getusermedia.html
 // The purpose of this base class is to be able to implement different
 // MediaStreaVideoSources such as local video capture, video sources received
 // on a PeerConnection or a source created in NaCl.
 // All methods calls will be done from the main render thread.
 //
 // When  the first track is added to the source by calling AddTrack
 // the MediaStreamVideoSource implementation calls GetCurrentSupportedFormats.
 // the source implementation must call OnSupportedFormats.
 // MediaStreamVideoSource then match the constraints provided in AddTrack with
 // the formats and call StartSourceImpl. The source implementation must call
 // OnStartDone when the underlying source has been started or failed to
 // start.
 class CONTENT_EXPORT MediaStreamVideoSource
     : public MediaStreamSource,
       NON_EXPORTED_BASE(public base::NonThreadSafe) {
  public:
   explicit MediaStreamVideoSource(MediaStreamDependencyFactory* factory);
   virtual ~MediaStreamVideoSource();
 
+  static MediaStreamVideoSource* GetVideoSource(

[Ronghua Wu (Left Chromium), 2014/03/01 01:26:04]

Put comments.

[perkj_chrome, 2014/03/02 09:20:44]

Done.

+      const blink::WebMediaStreamSource& source);
+
   // Puts |track| in the registered tracks list.
   virtual void AddTrack(const blink::WebMediaStreamTrack& track,

[Alpha Left Google, 2014/02/28 02:49:22]

This is odd. I think it should just take the native track instead of a web
track. The implementation of this method doesn't actually need a
WebMediaStreamTrack. Also it is more consistent to match RemoveTrack() below.

[Ronghua Wu (Left Chromium), 2014/03/01 01:26:04]

Make sense.

And I saw you called RemoveTrack from the ~MediaStreamVideoTrack, I think it
should be possible to call AddTrack in MediaStreamVideoTrack ctor.

[perkj_chrome, 2014/03/02 09:20:44]

I can not call AddTrack in the ctor. gUM needs to know the result of AddTrack.
On 2014/03/01 01:26:04, Ronghua Wu wrote:

[perkj_chrome, 2014/03/02 09:20:44]

ok - but then I need to change the base class and have separate AddTrack for
audio and video. But it probably make sence. 

[Alpha Left Google, 2014/03/03 06:45:04]

Okay.

                         const blink::WebMediaConstraints& constraints,
                         const ConstraintsCallback& callback) OVERRIDE;
-  virtual void RemoveTrack(const blink::WebMediaStreamTrack& track) OVERRIDE;
+  void RemoveTrack(MediaStreamVideoTrack* track);
 
   // TODO(ronghuawu): Remove webrtc::VideoSourceInterface from the public
   // interface of this class.
   // This creates a VideoSourceInterface implementation if it does not already
   // exist.
   webrtc::VideoSourceInterface* GetAdapter();
 
   // Constraint keys used by a video source.
   // Specified by draft-alvestrand-constraints-resolution-00b
   static const char kMinAspectRatio[];  // minAspectRatio
@@ skipping 81 matching lines @@
                          const ConstraintsCallback& callback);
     ~RequestedConstraints();
 
     blink::WebMediaConstraints constraints;
     ConstraintsCallback callback;
   };
   std::vector<RequestedConstraints> requested_constraints_;
 
   media::VideoCaptureFormats supported_formats_;
 
+  // Tracks that currently are receiving video frames.
+  std::vector<MediaStreamVideoTrack*> tracks_;
+
   // TODO(perkj): The below classes use webrtc/libjingle types. The goal is to
   // get rid of them as far as possible.
   MediaStreamDependencyFactory* factory_;
   scoped_refptr<webrtc::VideoSourceInterface> adapter_;
   WebRtcVideoCapturerAdapter* capture_adapter_;
 
   DISALLOW_COPY_AND_ASSIGN(MediaStreamVideoSource);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_MEDIA_MEDIA_STREAM_VIDEO_SOURCE_H_