MediaStream audio: Refactor 3 separate "glue" implementations into one.

content/renderer/media/webrtc/media_stream_remote_audio_track.h

-// Copyright 2015 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_WEBRTC_MEDIA_STREAM_REMOTE_AUDIO_TRACK_H_
-#define CONTENT_RENDERER_MEDIA_WEBRTC_MEDIA_STREAM_REMOTE_AUDIO_TRACK_H_
-
-#include "base/memory/ref_counted.h"
-#include "base/threading/thread_checker.h"
-#include "content/renderer/media/media_stream_audio_track.h"
-#include "third_party/WebKit/public/platform/WebMediaStreamSource.h"
-
-namespace content {
-
-class MediaStreamRemoteAudioSource;
-
-// MediaStreamRemoteAudioTrack is a WebRTC specific implementation of an
-// audio track received from a PeerConnection.
-// TODO(tommi): Chrome shouldn't have to care about remote vs local so
-// we should have a single track implementation that delegates to the
-// sources that do different things depending on the type of source.
-class MediaStreamRemoteAudioTrack : public MediaStreamAudioTrack {
- public:
-  explicit MediaStreamRemoteAudioTrack(
-      const blink::WebMediaStreamSource& source, bool enabled);
-  ~MediaStreamRemoteAudioTrack() override;
-
-  // MediaStreamTrack override.
-  void SetEnabled(bool enabled) override;
-
-  // MediaStreamAudioTrack overrides.
-  void AddSink(MediaStreamAudioSink* sink) override;
-  void RemoveSink(MediaStreamAudioSink* sink) override;
-  media::AudioParameters GetOutputFormat() const override;
-
-  webrtc::AudioTrackInterface* GetAudioAdapter() override;
-
- private:
-  // MediaStreamAudioTrack override.
-  void OnStop() final;
-
-  MediaStreamRemoteAudioSource* source() const;
-
-  blink::WebMediaStreamSource source_;
-  bool enabled_;
-};
-
-// Inheriting from ExtraData directly since MediaStreamAudioSource has
-// too much unrelated bloat.
-// TODO(tommi): MediaStreamAudioSource needs refactoring.
-// TODO(miu): On it!  ;-)
-class MediaStreamRemoteAudioSource
-    : public blink::WebMediaStreamSource::ExtraData {
- public:
-  explicit MediaStreamRemoteAudioSource(
-      const scoped_refptr<webrtc::AudioTrackInterface>& track);
-  ~MediaStreamRemoteAudioSource() override;
-
-  // Controls whether or not the source is included in the main, mixed, audio
-  // output from WebRTC as rendered by WebRtcAudioRenderer (media players).
-  void SetEnabledForMixing(bool enabled);
-
-  // Adds an audio sink for a track belonging to this source.
-  // |enabled| is the enabled state of the track and can be updated via
-  // a call to SetSinksEnabled.
-  void AddSink(MediaStreamAudioSink* sink, MediaStreamAudioTrack* track,
-               bool enabled);
-
-  // Removes an audio sink for a track belonging to this source.
-  void RemoveSink(MediaStreamAudioSink* sink, MediaStreamAudioTrack* track);
-
-  // Turns audio callbacks on/off for all sinks belonging to a track.
-  void SetSinksEnabled(MediaStreamAudioTrack* track, bool enabled);
-
-  // Removes all sinks belonging to a track.
-  void RemoveAll(MediaStreamAudioTrack* track);
-
-  webrtc::AudioTrackInterface* GetAudioAdapter();
-
- private:
-  class AudioSink;
-  scoped_ptr<AudioSink> sink_;
-  const scoped_refptr<webrtc::AudioTrackInterface> track_;
-  base::ThreadChecker thread_checker_;
-};
-
-}  // namespace content
-
-#endif  // CONTENT_RENDERER_MEDIA_WEBRTC_MEDIA_STREAM_REMOTE_AUDIO_TRACK_H_