Switching audio clients to using RestartableAudioRendererSink interface as a sink.

content/renderer/media/restartable_audio_output_device_factory.cc

+// Copyright (c) 2012 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 "content/renderer/media/restartable_audio_output_device_factory.h"
+
+#include "content/renderer/media/audio_device_factory.h"
+#include "content/renderer/media/audio_renderer_mixer_manager.h"
+#include "content/renderer/render_thread_impl.h"
+#include "media/audio/audio_output_device.h"
+#include "media/audio/restartable_audio_output_device_impl.h"
+#include "media/base/audio_renderer_mixer_input.h"
+#include "url/origin.h"
+
+namespace content {
+
+RestartableAudioOutputDeviceFactory*
+    RestartableAudioOutputDeviceFactory::factory_ = nullptr;
+
+namespace {
+
+// This is where we decide which audio will go to mixers and wich one to
+// AudioOutpuDevice directly.
+bool IsMixable(RestartableAudioOutputDeviceFactory::SourceType source_type) {
+  if (source_type == RestartableAudioOutputDeviceFactory::kSourceHighLatency)
+    return true;  // Must ALWAYS go through mixer.
+
+  // TODO(olka): make a decision for the rest of the sources basing on OS
+  // type and configuration parameters.
+  return false;
+}
+
+scoped_refptr<media::RestartableAudioRendererSink> NewMixableSink(
+    int render_frame_id,
+    const std::string& device_id,
+    const url::Origin& security_origin) {
+  RenderThreadImpl* render_thread = RenderThreadImpl::current();
+  return render_thread->GetAudioRendererMixerManager()->CreateInput(
+      render_frame_id, device_id, security_origin);
+}
+
+scoped_refptr<media::RestartableAudioRendererSink> NewUnmixableSink(
+    int render_frame_id,
+    int session_id,
+    const std::string& device_id,
+    const url::Origin& security_origin) {
+  return new media::RestartableAudioOutputDeviceImpl(
+      base::Bind(&AudioDeviceFactory::NewOutputDevice, render_frame_id,
+                 session_id, device_id, security_origin),
+      base::Bind(&RestartableAudioOutputDeviceFactory::GetOutputHWParams,
+                 render_frame_id, session_id, device_id, security_origin));
+}
+
+}  // namespace
+
+// static
+scoped_refptr<media::RestartableAudioRendererSink>
+RestartableAudioOutputDeviceFactory::NewOutputDevice(
+    SourceType source_type,
+    int render_frame_id,
+    int session_id,
+    const std::string& device_id,
+    const url::Origin& security_origin) {
+  if (factory_) {
+    media::RestartableAudioRendererSink* const device =
+        factory_->CreateOutputDevice(source_type, render_frame_id, session_id,
+                                     device_id, security_origin);
+    if (device)
+      return device;
+  }
+
+  if (IsMixable(source_type))
+    return NewMixableSink(render_frame_id, device_id, security_origin);
+
+  return NewUnmixableSink(render_frame_id, session_id, device_id,
+                          security_origin);
+}
+
+RestartableAudioOutputDeviceFactory::RestartableAudioOutputDeviceFactory() {
+  DCHECK(!factory_) << "Can't register two factories at once.";
+  factory_ = this;
+}
+
+RestartableAudioOutputDeviceFactory::~RestartableAudioOutputDeviceFactory() {
+  factory_ = NULL;
+}
+
+// static
+media::AudioParameters RestartableAudioOutputDeviceFactory::GetOutputHWParams(

[DaleCurtis, 2016/02/08 19:10:25]

This adds overhead that I don't think we want. When I was looking at a similar
change, I was thinking that instead the ARMM could first try to find an existing
mixer that has an open sink for the given device/origin and return its
parameters. Failing that it can create a sink into a temporary pool which will
be kept alive for a subsequent GetMixer() request; if no request comes in within
some time the pool can be released.

I don't believe this ends up creating shmem or a thread (since those happen on
CreateStream), but still the round trip w/ a waitable event is unfortunate to do
more than necessary.

[o1ka, 2016/02/09 14:15:38]

This is a great idea. I'll take care of it.

+    int render_frame_id,
+    int session_id,
+    const std::string& device_id,
+    const url::Origin& security_origin) {
+  media::AudioParameters params;  // Invalid parameters to return by default.
+
+  // AudioOutputDevice is the only interface we have to communicate with output
+  // device via IPC. So, that's how we get the parameters when there is no
+  // AudioOutputDevice:
+  scoped_refptr<media::AudioOutputDevice> aod =
+      AudioDeviceFactory::NewOutputDevice(render_frame_id, session_id,
+                                          device_id, security_origin);
+
+  if (aod->GetDeviceStatus() == media::OUTPUT_DEVICE_STATUS_OK)
+    params = aod->GetOutputParameters();
+
+  aod->Stop();  // Must be stopped.
+  return params;
+}
+
+}  // namespace content