Adding audio support to the new webmediaplyer

media/base/rtc_audio_renderer.h

+// Copyright (c) 2012 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 MEDIA_BASE_RTC_AUDIO_RENDERER_H_
+#define MEDIA_BASE_RTC_AUDIO_RENDERER_H_
+
+#include "base/memory/ref_counted.h"
+#include "media/base/media_export.h"
+
+namespace media {
+
+class MEDIA_EXPORT RtcAudioRenderer

[scherkus (not reviewing), 2012/10/25 17:47:39]

I don't see any reason why this has to be in ./media (there's no code inside of
./media that makes use of this interface). Can you move this beside
VideoFrameProvider under ./webkit/media?

Also the name isn't very descriptive. It's returned by MediaStreamClient and is
used by the MediaStream version of WebMediaPlayer -- perhaps have the word
"Stream" in there as opposed to "RTC"? (media streams don't necessarily go over
RTC...)

[no longer working on chromium, 2012/10/26 09:35:29]

Good idea, I was also not sure if the location and name of this interface are
correct. I will move it to webkit/media, and change the name to
media_stream_audio_renderer.h

+    : public base::RefCountedThreadSafe<RtcAudioRenderer> {

[scherkus (not reviewing), 2012/10/25 17:47:39]

what necessitates this being refcounted?

[no longer working on chromium, 2012/10/26 09:35:29]

This needs to be ref-counted because it is used by both WebAudioDeviceImpl and
WebMediaPlayerMS, and it is unsure who will go away first.
And in the future, we also need to keep a ref of the object in the AudioTrack,
for features like connecting one remote AudioTrack's rendered data to a local
AudioTrack's capture source, and send it out via peerconnection.

+ public:
+  // Starts rendering audio.
+  virtual void Play() = 0;
+
+  // Temporarily suspends rendering audio.
+  virtual void Pause() = 0;
+
+  // Stops all operations in preparation for being deleted.
+  virtual void Stop() = 0;
+
+  // Sets the output volume.
+  virtual void SetVolume(float volume) = 0;
+
+ protected:
+  friend class base::RefCountedThreadSafe<RtcAudioRenderer>;
+
+  RtcAudioRenderer();
+  virtual ~RtcAudioRenderer();
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(RtcAudioRenderer);
+};
+
+}  // namespace media
+
+#endif  // MEDIA_BASE_AUDIO_RENDERER_H_