[chromecast] Moves CastAudioOutputStream::Backend to CMA thread.

chromecast/media/audio/cast_audio_manager.cc

 // 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.
 
 #include "chromecast/media/audio/cast_audio_manager.h"
 
 #include <algorithm>
 #include <string>
 
 #include "base/bind.h"
+#include "base/memory/ptr_util.h"
 #include "chromecast/media/audio/cast_audio_mixer.h"
 #include "chromecast/media/audio/cast_audio_output_stream.h"
-#include "chromecast/media/cma/backend/media_pipeline_backend_manager.h"
+#include "chromecast/media/cma/backend/media_pipeline_backend_factory.h"
+#include "chromecast/public/media/media_pipeline_backend.h"
 
 namespace {
 // TODO(alokp): Query the preferred value from media backend.
 const int kDefaultSampleRate = 48000;
 
 // Define bounds for the output buffer size (in frames).
 // Note: These values are copied from AudioManagerPulse implementation.
 // TODO(alokp): Query the preferred value from media backend.
 static const int kMinimumOutputBufferSize = 512;
 static const int kMaximumOutputBufferSize = 8192;
 static const int kDefaultOutputBufferSize = 2048;
 }  // namespace
 
 namespace chromecast {
 namespace media {
 
 CastAudioManager::CastAudioManager(
     std::unique_ptr<::media::AudioThread> audio_thread,
     ::media::AudioLogFactory* audio_log_factory,
-    MediaPipelineBackendManager* backend_manager)
-    : CastAudioManager(std::move(audio_thread),
-                       audio_log_factory,
-                       backend_manager,
-                       new CastAudioMixer(
-                           base::Bind(&CastAudioManager::MakeMixerOutputStream,
-                                      base::Unretained(this)))) {}
-
-CastAudioManager::CastAudioManager(
-    std::unique_ptr<::media::AudioThread> audio_thread,
-    ::media::AudioLogFactory* audio_log_factory,
-    MediaPipelineBackendManager* backend_manager,
-    CastAudioMixer* audio_mixer)
+    std::unique_ptr<MediaPipelineBackendFactory> backend_factory,
+    scoped_refptr<base::SingleThreadTaskRunner> backend_task_runner,
+    bool use_mixer)
     : AudioManagerBase(std::move(audio_thread), audio_log_factory),
-      backend_manager_(backend_manager),
-      mixer_(audio_mixer) {}
+      backend_factory_(std::move(backend_factory)),
+      backend_task_runner_(std::move(backend_task_runner)) {
+  if (use_mixer)
+    mixer_ = base::MakeUnique<CastAudioMixer>(this);
+}
 
 CastAudioManager::~CastAudioManager() = default;
 
 bool CastAudioManager::HasAudioOutputDevices() {
   return true;
 }
 
 bool CastAudioManager::HasAudioInputDevices() {
   return false;
 }
@@ skipping 14 matching lines @@
   // Need to send a valid AudioParameters object even when it will unused.
   return ::media::AudioParameters(
       ::media::AudioParameters::AUDIO_PCM_LOW_LATENCY,
       ::media::CHANNEL_LAYOUT_STEREO, 48000, 16, 1024);
 }
 
 const char* CastAudioManager::GetName() {
   return "Cast";
 }
 
-std::unique_ptr<MediaPipelineBackend>
-CastAudioManager::CreateMediaPipelineBackend(
-    const MediaPipelineDeviceParams& params) {
-  return backend_manager_->CreateMediaPipelineBackend(params);
-}
-
 void CastAudioManager::ReleaseOutputStream(::media::AudioOutputStream* stream) {
   // If |stream| is |mixer_output_stream_|, we should not use
   // AudioManagerBase::ReleaseOutputStream as we do not want the release
   // function to decrement |AudioManagerBase::num_output_streams_|. This is
   // because the stream generated from MakeMixerOutputStream was not created
   // using AudioManagerBase::MakeAudioOutputStream, which appropriately
   // increments this variable.
   if (mixer_output_stream_.get() == stream) {
     DCHECK(mixer_);  // Should only occur if |mixer_| exists
     mixer_output_stream_.reset();
   } else {
     AudioManagerBase::ReleaseOutputStream(stream);
   }
 }
 
 ::media::AudioOutputStream* CastAudioManager::MakeLinearOutputStream(
     const ::media::AudioParameters& params,
     const ::media::AudioManager::LogCallback& log_callback) {
   DCHECK_EQ(::media::AudioParameters::AUDIO_PCM_LINEAR, params.format());
 
   // If |mixer_| exists, return a mixing stream.
   if (mixer_)
-    return mixer_->MakeStream(params, this);
+    return mixer_->MakeStream(params);
   else
     return new CastAudioOutputStream(params, this);
 }
 
 ::media::AudioOutputStream* CastAudioManager::MakeLowLatencyOutputStream(
     const ::media::AudioParameters& params,
     const std::string& device_id,
     const ::media::AudioManager::LogCallback& log_callback) {
   DCHECK_EQ(::media::AudioParameters::AUDIO_PCM_LOW_LATENCY, params.format());
 
   // If |mixer_| exists, return a mixing stream.
   if (mixer_)
-    return mixer_->MakeStream(params, this);
+    return mixer_->MakeStream(params);
   else
     return new CastAudioOutputStream(params, this);
 }
 
 ::media::AudioInputStream* CastAudioManager::MakeLinearInputStream(
     const ::media::AudioParameters& params,
     const std::string& device_id,
     const ::media::AudioManager::LogCallback& log_callback) {
   LOG(WARNING) << "No support for input audio devices";
   return nullptr;
@@ skipping 37 matching lines @@
   DCHECK(!mixer_output_stream_);  // Only allow 1 |mixer_output_stream_|.
 
   // Keep a reference to this stream for proper behavior on
   // CastAudioManager::ReleaseOutputStream.
   mixer_output_stream_.reset(new CastAudioOutputStream(params, this));
   return mixer_output_stream_.get();
 }
 
 }  // namespace media
 }  // namespace chromecast