[Chromecast] Plumbs raw audio through CMA backend.

chromecast/media/audio/audio_manager.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 CHROMECAST_MEDIA_AUDIO_AUDIO_MANAGER_H_
+#define CHROMECAST_MEDIA_AUDIO_AUDIO_MANAGER_H_
+
+#include "media/audio/audio_manager_base.h"
+
+namespace chromecast {

[slan, 2015/08/31 16:59:56]

nit: This can simply be declared inside the namespace below, I think. Is there
preference in Chrome?

[alokp, 2015/09/01 00:23:11]

Done.

+class TaskRunnerImpl;
+}  // namespace chromecast
+
+namespace chromecast {
+namespace media {
+
+class MediaPipelineBackend;
+
+class AudioManager : public ::media::AudioManagerBase {
+ public:
+  AudioManager(::media::AudioLogFactory* audio_log_factory);
+  ~AudioManager() override;
+
+  // AudioManager implementation.
+  bool HasAudioOutputDevices() override;
+  bool HasAudioInputDevices() override;
+  void ShowAudioInputSettings() override;
+  void GetAudioInputDeviceNames(
+      ::media::AudioDeviceNames* device_names) override;
+  ::media::AudioParameters GetInputStreamParameters(
+      const std::string& device_id) override;
+
+  // In production, this must be called on audio thread.
+  // See AudioManager::GetTaskRunner.
+  virtual scoped_ptr<MediaPipelineBackend> CreateMediaPipelineBackend();

[halliwell, 2015/08/28 15:14:18]

I'm not clear what this is for.  Can't we always just create the media pipeline
backend through CastMediaShlib?

[alokp, 2015/09/01 00:23:11]

Will explain offline.

+
+ private:
+  // AudioManagerBase implementation.
+  ::media::AudioOutputStream* MakeLinearOutputStream(
+      const ::media::AudioParameters& params) override;
+  ::media::AudioOutputStream* MakeLowLatencyOutputStream(
+      const ::media::AudioParameters& params,
+      const std::string& device_id) override;
+  ::media::AudioInputStream* MakeLinearInputStream(
+      const ::media::AudioParameters& params,
+      const std::string& device_id) override;
+  ::media::AudioInputStream* MakeLowLatencyInputStream(
+      const ::media::AudioParameters& params,
+      const std::string& device_id) override;
+  ::media::AudioParameters GetPreferredOutputStreamParameters(
+      const std::string& output_device_id,
+      const ::media::AudioParameters& input_params) override;
+
+  scoped_ptr<TaskRunnerImpl> audio_task_runner_;
+
+  DISALLOW_COPY_AND_ASSIGN(AudioManager);
+};
+
+}  // namespace media
+}  // namespace chromecast
+
+#endif  // CHROMECAST_MEDIA_AUDIO_AUDIO_MANAGER_H_