[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 {
+
+class TaskRunnerImpl;
+
+namespace media {
+
+class MediaPipelineBackend;
+
+class AudioManager : public ::media::AudioManagerBase {

[gunsch, 2015/09/18 21:23:07]

I know it's namespaced, but can we call this CastAudioManager to better
distinguish from ::media::AudioManager? This is already a convention with our
other implementation classes (CastBrowserCdmFactory, CastBrowserContext,
CastMetricsServiceClient, etc.

[alokp, 2015/09/18 21:42:14]

SGTM. Should I rename AudioOutputStream to CastAudioOutputStream too?

[gunsch, 2015/09/18 21:57:06]

Please do, thanks.

+ public:
+  AudioManager(::media::AudioLogFactory* audio_log_factory);

[gunsch, 2015/09/18 21:23:07]

nit: explicit

[alokp, 2015/09/18 21:42:14]

Done.

+  ~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.

[gunsch, 2015/09/18 21:23:07]

Why "in production"? Shouldn't this assumption either always or never be the
case?

[alokp, 2015/09/18 21:42:14]

This is not true in unittest, where I do not create an audio thread. I will
check if I can fake the audio thread in the unittest.

+  // See AudioManager::GetTaskRunner.
+  virtual scoped_ptr<MediaPipelineBackend> CreateMediaPipelineBackend();
+
+ 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);

[gunsch, 2015/09/18 21:23:07]

nit: #include "base/macros.h"

[alokp, 2015/09/18 21:42:15]

Done.

+};
+
+}  // namespace media
+}  // namespace chromecast
+
+#endif  // CHROMECAST_MEDIA_AUDIO_AUDIO_MANAGER_H_