Add VideoTrackSink interface to content/public

content/public/renderer/media_stream_video_sink.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_PUBLIC_RENDERER_MEDIA_STREAM_VIDEO_SINK_H_
+#define CONTENT_PUBLIC_RENDERER_MEDIA_STREAM_VIDEO_SINK_H_
+
+#include "base/compiler_specific.h"
+#include "base/memory/ref_counted.h"
+#include "content/common/content_export.h"
+#include "content/public/renderer/media_stream_sink.h"
+
+namespace media {
+class VideoFrame;
+}
+
+namespace blink {
+class WebMediaStreamTrack;
+}
+
+namespace content {
+
+class CONTENT_EXPORT MediaStreamVideoSink : public MediaStreamSink {

[Alpha Left Google, 2013/11/27 22:13:15]

I think we should document the threading requirement of this API. For example on
which thread will this method be called?

[perkj_chrome, 2013/11/28 13:32:45]

Done.

+ public:
+  virtual void OnVideoFrame(const scoped_refptr<media::VideoFrame>& frame) = 0;
+
+ protected:
+  virtual ~MediaStreamVideoSink() {}
+};
+
+// An implementation of MediaStreamVideoSink should call AddToVideoTrack when it
+// is ready to receive data from a video track. Before the implementation is
+// destroyed, RemoveFromVideoTrack must be called.
+CONTENT_EXPORT void AddToVideoTrack(MediaStreamVideoSink* sink,

[Alpha Left Google, 2013/11/27 22:13:15]

We should document the threading requirement of this API. On which thread should
this be called? It seems this function should be called on the main thread
because of the use of blink objects.

[perkj_chrome, 2013/11/28 13:32:45]

Done.

+                                    const blink::WebMediaStreamTrack& track);

[no longer working on chromium, 2013/11/28 15:12:34]

nit, add and empty line.

+CONTENT_EXPORT void RemoveFromVideoTrack(
+    MediaStreamVideoSink* sink,
+    const blink::WebMediaStreamTrack& track);
+
+}  // namespace content
+
+#endif  // CONTENT_PUBLIC_RENDERER_MEDIA_STREAM_VIDEO_SINK_H_