Unmute Tab Audio For Desktop Share

media/audio/virtual_audio_sink.h

+// Copyright (c) 2016 The Chromium Authors. All rights reserved.

[miu, 2016/05/02 20:06:14]

No "(c)" in copyright headers anymore.

[qiangchen, 2016/05/03 16:58:24]

Done.

+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef MEDIA_AUDIO_VIRTUAL_AUDIO_SINK_H_
+#define MEDIA_AUDIO_VIRTUAL_AUDIO_SINK_H_
+
+#include "base/callback.h"
+#include "base/macros.h"
+#include "media/audio/audio_io.h"
+#include "media/base/audio_converter.h"
+#include "media/base/audio_shifter.h"
+
+namespace media {
+
+class VirtualAudioInputStream;
+
+class MEDIA_EXPORT AudioPushSink {

[miu, 2016/05/02 20:06:14]

This AudioPushSink interface should probably be placed in
audio_source_diverter.h instead (or even its own header file, but that may be
overkill).

[qiangchen, 2016/05/03 16:58:24]

Done.

+ public:
+  virtual void OnData(const AudioBus& source,
+                      base::TimeTicks reference_time) = 0;
+  virtual void Close() = 0;
+};
+
+// This class is an adapter between push model and pull model for audio stream.
+// Audio provider calls OnData() to push audio data into this class.
+// Audio consumer calls ProvideInput() to pull audio data.
+class MEDIA_EXPORT VirtualAudioSink : public AudioPushSink,
+                                      public AudioConverter::InputCallback {
+ public:
+  typedef base::Callback<void(VirtualAudioSink* sink)> AfterCloseCallback;
+
+  // Construct an audio loopback pathway to the given |target| (not owned).
+  // |target| must outlive this instance.
+  VirtualAudioSink(AudioParameters param,
+                   VirtualAudioInputStream* target,
+                   AfterCloseCallback callback);
+  ~VirtualAudioSink() override;
+
+  // AudioPushSink
+  void Close() override;
+  void OnData(const AudioBus& source, base::TimeTicks reference_time) override;
+
+  // AudioConverter::InputCallback
+  double ProvideInput(AudioBus* audio_bus,
+                      base::TimeDelta buffer_delay) override;
+
+ private:
+  AudioParameters params_;

[miu, 2016/05/02 20:06:14]

Since these members should never change after initialization:

  const AudioParameters params_;
  VirtualAudioInputStream* const target_;

[qiangchen, 2016/05/03 16:58:24]

Done.

+  VirtualAudioInputStream* target_;
+  AudioShifter shifter_;
+  AfterCloseCallback after_close_callback_;
+};
+
+}  // namespace media
+
+#endif  // MEDIA_AUDIO_VIRTUAL_AUDIO_SINK_H_