Add VideoTrackSink interface to content/public

content/public/renderer/media/media_track_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_MEDIA_TRACK_SINK_H_
+#define CONTENT_PUBLIC_RENDERER_MEDIA_MEDIA_TRACK_SINK_H_
+
+#include "base/compiler_specific.h"
+#include "content/common/content_export.h"
+
+namespace blink {
+class WebMediaStreamTrack;
+}
+
+namespace content {
+
+class CONTENT_EXPORT MediaTrackSink {

[Jói, 2013/11/25 14:06:55]

We might want to name this just MediaSink (and VideoSink/AudioSink) since we'll
probably want the same interface e.g. on a track for a source to push to, and
evne on a source for e.g. a microphone to push to.

[perkj_chrome, 2013/11/26 09:16:38]

Do we need anything to say that this is related to MediaStreams in the name? I
like MediaSink but it is very generic.

+ public:
+
+  // TODO(perkj): Can we use blink::WebMediaStreamSource::ReadyState somehow

[Jói, 2013/11/25 14:06:55]

We can include blink types in content/public/ (see e.g.
content/public/renderer/render_view.h which uses blink::NavigationPolicy and
others), so this shouldn't be a problem.

[perkj_chrome, 2013/11/26 09:16:38]

Done.

+  // and skip ReadyState here and below?
+  enum ReadyState {
+      kLive = 0,
+      kMuted = 1,
+      kEnded = 2
+  };
+  //virtual void OnEnabledChanged(bool enabled) {};
+  virtual void OnSourceChangedState(ReadyState state) {};

[no longer working on chromium, 2013/11/25 13:55:07]

Do the sink need to know the source? or only track?

[perkj_chrome, 2013/11/26 09:16:38]

It will problably (as in this cl) need to know the readyState. In blink- this is
implemented on the source. We can call this ReadyStateChanged.

+
+  ReadyState GetSourceState(const blink::WebMediaStreamTrack& track) const;

[Jói, 2013/11/25 14:06:55]

Once you create the sink, it presumably could store a non-owning pointer to its
track, so you shouldn't have to pass the track into this method.

This also makes the interface less specific to a track.

[perkj_chrome, 2013/11/26 09:16:38]

We don't need this if we can use the blink readyState.

+
+ protected:
+  virtual ~MediaTrackSink() {}
+};
+
+}  // namespace content
+
+#endif  // CONTENT_PUBLIC_RENDERER_MEDIA_MEDIA_TRACK_SINK_H_