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

content/renderer/media/webrtc/webrtc_local_audio_track_adapter.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_WEBRTC_WEBRTC_LOCAL_AUDIO_TRACK_ADAPTER_H_
-#define CONTENT_RENDERER_MEDIA_WEBRTC_WEBRTC_LOCAL_AUDIO_TRACK_ADAPTER_H_
-
-#include <vector>
-
-#include "base/memory/ref_counted.h"
-#include "base/memory/scoped_vector.h"
-#include "base/single_thread_task_runner.h"
-#include "base/synchronization/lock.h"
-#include "content/common/content_export.h"
-#include "content/renderer/media/media_stream_audio_level_calculator.h"
-#include "content/renderer/media/media_stream_audio_processor.h"
-#include "third_party/webrtc/api/mediastreamtrack.h"
-#include "third_party/webrtc/media/base/audiorenderer.h"
-
-namespace cricket {
-class AudioRenderer;
-}
-
-namespace webrtc {
-class AudioSourceInterface;
-class AudioProcessorInterface;
-}
-
-namespace content {
-
-class MediaStreamAudioProcessor;
-class WebRtcAudioSinkAdapter;
-class WebRtcLocalAudioTrack;
-
-// Provides an implementation of the webrtc::AudioTrackInterface that can be
-// bound/unbound to/from a MediaStreamAudioTrack.  In other words, this is an
-// adapter that sits between the media stream object graph and WebRtc's object
-// graph and proxies between the two.
-class CONTENT_EXPORT WebRtcLocalAudioTrackAdapter
-    : NON_EXPORTED_BASE(
-          public webrtc::MediaStreamTrack<webrtc::AudioTrackInterface>) {
- public:
-  static scoped_refptr<WebRtcLocalAudioTrackAdapter> Create(
-      const std::string& label,
-      webrtc::AudioSourceInterface* track_source);
-
-  WebRtcLocalAudioTrackAdapter(
-      const std::string& label,
-      webrtc::AudioSourceInterface* track_source,
-      scoped_refptr<base::SingleThreadTaskRunner> signaling_task_runner);
-
-  ~WebRtcLocalAudioTrackAdapter() override;
-
-  void Initialize(WebRtcLocalAudioTrack* owner);
-
-  // Set the object that provides shared access to the current audio signal
-  // level.  This method may only be called once, before the audio data flow
-  // starts, and before any calls to GetSignalLevel() might be made.
-  void SetLevel(scoped_refptr<MediaStreamAudioLevelCalculator::Level> level);
-
-  // Method called by the WebRtcLocalAudioTrack to set the processor that
-  // applies signal processing on the data of the track.
-  // This class will keep a reference of the |processor|.
-  // Called on the main render thread.
-  // This method may only be called once, before the audio data flow starts, and
-  // before any calls to GetAudioProcessor() might be made.
-  void SetAudioProcessor(scoped_refptr<MediaStreamAudioProcessor> processor);
-
-  // webrtc::MediaStreamTrack implementation.
-  std::string kind() const override;
-  bool set_enabled(bool enable) override;
-
- private:
-  // webrtc::AudioTrackInterface implementation.
-  void AddSink(webrtc::AudioTrackSinkInterface* sink) override;
-  void RemoveSink(webrtc::AudioTrackSinkInterface* sink) override;
-  bool GetSignalLevel(int* level) override;
-  rtc::scoped_refptr<webrtc::AudioProcessorInterface> GetAudioProcessor()
-      override;
-  webrtc::AudioSourceInterface* GetSource() const override;
-
-  // Weak reference.
-  WebRtcLocalAudioTrack* owner_;
-
-  // The source of the audio track which handles the audio constraints.
-  // TODO(xians): merge |track_source_| to |capturer_| in WebRtcLocalAudioTrack.
-  rtc::scoped_refptr<webrtc::AudioSourceInterface> track_source_;
-
-  // Libjingle's signaling thread.
-  const scoped_refptr<base::SingleThreadTaskRunner> signaling_task_runner_;
-
-  // The audio processsor that applies audio processing on the data of audio
-  // track.  This must be set before calls to GetAudioProcessor() are made.
-  scoped_refptr<MediaStreamAudioProcessor> audio_processor_;
-
-  // A vector of the peer connection sink adapters which receive the audio data
-  // from the audio track.
-  ScopedVector<WebRtcAudioSinkAdapter> sink_adapters_;
-
-  // Thread-safe accessor to current audio signal level.  This must be set
-  // before calls to GetSignalLevel() are made.
-  scoped_refptr<MediaStreamAudioLevelCalculator::Level> level_;
-};
-
-}  // namespace content
-
-#endif  // CONTENT_RENDERER_MEDIA_WEBRTC_WEBRTC_LOCAL_AUDIO_TRACK_ADAPTER_H_