Switching AudioInputDeviceManager from using AudioManager interface to AudioSystem one.

media/audio/audio_system_impl.cc

 // Copyright 2017 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 "media/audio/audio_system_impl.h"
 
 #include "base/memory/ptr_util.h"
 #include "base/single_thread_task_runner.h"
 #include "base/task_runner_util.h"
 #include "media/audio/audio_device_description.h"
 #include "media/audio/audio_manager.h"
+#include "media/base/bind_to_current_loop.h"
 
 // Using base::Unretained for |audio_manager_| is safe since it is deleted after
 // its task runner, and AudioSystemImpl is deleted on the UI thread after the IO
 // thread has been stopped and before |audio_manager_| deletion is scheduled.
 namespace media {
 
 namespace {
 
 AudioParameters GetInputParametersOnDeviceThread(AudioManager* audio_manager,
                                                  const std::string& device_id) {
@@ skipping 28 matching lines @@
     bool for_input) {
   DCHECK(audio_manager->GetTaskRunner()->BelongsToCurrentThread());
   AudioDeviceDescriptions descriptions;
   if (for_input)
     audio_manager->GetAudioInputDeviceDescriptions(&descriptions);
   else
     audio_manager->GetAudioOutputDeviceDescriptions(&descriptions);
   return descriptions;
 }
 
+void GetInputDeviceInfoOnDeviceThread(
+    AudioManager* audio_manager,
+    const std::string& input_device_id,
+    AudioSystem::OnInputDeviceInfoCallback on_input_device_info_cb) {
+  DCHECK(audio_manager->GetTaskRunner()->BelongsToCurrentThread());
+  const std::string associated_output_device_id =
+      audio_manager->GetAssociatedOutputDeviceID(input_device_id);
+
+  on_input_device_info_cb.Run(
+      GetInputParametersOnDeviceThread(audio_manager, input_device_id),
+      associated_output_device_id.empty()
+          ? AudioParameters()
+          : GetOutputParametersOnDeviceThread(audio_manager,
+                                              associated_output_device_id),
+      associated_output_device_id);
+}
+
 }  // namespace
 
 AudioSystemImpl::AudioSystemImpl(AudioManager* audio_manager)
     : audio_manager_(audio_manager) {
   DCHECK(audio_manager_);
   AudioSystem::SetInstance(this);
 }
 
 AudioSystemImpl::~AudioSystemImpl() {
   AudioSystem::ClearInstance(this);
@@ skipping 45 matching lines @@
     return;
   }
   base::PostTaskAndReplyWithResult(
       GetTaskRunner(), FROM_HERE,
       base::Bind(&AudioManager::HasAudioInputDevices,
                  base::Unretained(audio_manager_)),
       std::move(on_has_devices_cb));
 }
 
 void AudioSystemImpl::GetDeviceDescriptions(
-    OnDeviceDescriptionsCallback on_descriptions_cp,
+    OnDeviceDescriptionsCallback on_descriptions_cb,
     bool for_input) {
   if (GetTaskRunner()->BelongsToCurrentThread()) {
     GetTaskRunner()->PostTask(
-        FROM_HERE, base::Bind(on_descriptions_cp,
+        FROM_HERE, base::Bind(on_descriptions_cb,
                               base::Passed(GetDeviceDescriptionsOnDeviceThread(
                                   audio_manager_, for_input))));
     return;
   }
 
   base::PostTaskAndReplyWithResult(
       GetTaskRunner(), FROM_HERE,
       base::Bind(&GetDeviceDescriptionsOnDeviceThread,
                  base::Unretained(audio_manager_), for_input),
-      std::move(on_descriptions_cp));
+      std::move(on_descriptions_cb));
 }
 
-AudioManager* AudioSystemImpl::GetAudioManager() const {
-  return audio_manager_;
+void AudioSystemImpl::GetAssociatedOutputDeviceID(
+    const std::string& input_device_id,
+    OnDeviceIdCallback on_device_id_cb) {
+  if (GetTaskRunner()->BelongsToCurrentThread()) {
+    GetTaskRunner()->PostTask(
+        FROM_HERE,
+        base::Bind(on_device_id_cb, audio_manager_->GetAssociatedOutputDeviceID(
+                                        input_device_id)));
+    return;
+  }
+  base::PostTaskAndReplyWithResult(
+      GetTaskRunner(), FROM_HERE,
+      base::Bind(&AudioManager::GetAssociatedOutputDeviceID,
+                 base::Unretained(audio_manager_), input_device_id),
+      std::move(on_device_id_cb));
+}
+
+void AudioSystemImpl::GetInputDeviceInfo(
+    const std::string& input_device_id,
+    OnInputDeviceInfoCallback on_input_device_info_cb) {
+  // No need to bind |on_input_device_info_cb| to the current loop if we are on
+  // the audio thread. However, the client still expect to receive the reply
+  // asynchronously, so we always post GetInputDeviceInfoOnDeviceThread(), which
+  // will syncronously call the (bound to current loop or not) callback.
+  GetTaskRunner()->PostTask(
+      FROM_HERE, base::Bind(&GetInputDeviceInfoOnDeviceThread,
+                            base::Unretained(audio_manager_), input_device_id,

[Guido Urdaneta, 2017/04/06 14:26:41]

When using Unretained, always explain why it is safe to do so.

[o1ka, 2017/04/07 12:22:17]

see ll.14-16: there is a file-wide comment there (otherwise I need to add it in
10+ places here).

+                            GetTaskRunner()->BelongsToCurrentThread()
+                                ? std::move(on_input_device_info_cb)
+                                : media::BindToCurrentLoop(
+                                      std::move(on_input_device_info_cb))));
 }
 
 base::SingleThreadTaskRunner* AudioSystemImpl::GetTaskRunner() const {
   return audio_manager_->GetTaskRunner();
 }
 
 }  // namespace media