Handle audio device changes on Mac (Take 2).

media/audio/mac/audio_manager_mac.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 <CoreAudio/AudioHardware.h>
 
 #include <string>
 
+#include "base/bind.h"
 #include "base/command_line.h"
 #include "base/mac/mac_logging.h"
 #include "base/mac/scoped_cftyperef.h"
 #include "base/sys_string_conversions.h"
+#include "media/audio/mac/audio_device_listener_mac.h"
 #include "media/audio/mac/audio_input_mac.h"
 #include "media/audio/mac/audio_low_latency_input_mac.h"
 #include "media/audio/mac/audio_low_latency_output_mac.h"
 #include "media/audio/mac/audio_manager_mac.h"
 #include "media/audio/mac/audio_output_mac.h"
 #include "media/audio/mac/audio_synchronized_mac.h"
 #include "media/audio/mac/audio_unified_mac.h"
+#include "media/base/bind_to_loop.h"
 #include "media/base/limits.h"
 #include "media/base/media_switches.h"
 
 namespace media {
 
 // Maximum number of output streams that can be open simultaneously.
 static const int kMaxOutputStreams = 50;
 
 static bool HasAudioHardware(AudioObjectPropertySelector selector) {
   AudioDeviceID output_device_id = kAudioObjectUnknown;
@@ skipping 198 matching lines @@
   }
 
   return audio_device_id;
 }
 
 AudioManagerMac::AudioManagerMac() {
   SetMaxOutputStreamsAllowed(kMaxOutputStreams);
 }
 
 AudioManagerMac::~AudioManagerMac() {
+  // It's safe to post a task here since Shutdown() will wait for all tasks to
+  // complete before returning.
+  GetMessageLoop()->PostTask(FROM_HERE, base::Bind(
+      &AudioManagerMac::DestructOnAudioThread, base::Unretained(this)));
   Shutdown();
 }
 
 bool AudioManagerMac::HasAudioOutputDevices() {
   return HasAudioHardware(kAudioHardwarePropertyDefaultOutputDevice);
 }
 
 bool AudioManagerMac::HasAudioInputDevices() {
   return HasAudioHardware(kAudioHardwarePropertyDefaultInputDevice);
 }
@@ skipping 50 matching lines @@
   // Gets the AudioDeviceID that refers to the AudioOutputDevice with the device
   // unique id. This AudioDeviceID is used to set the device for Audio Unit.
   AudioDeviceID audio_device_id = GetAudioDeviceIdByUId(true, device_id);
   AudioInputStream* stream = NULL;
   if (audio_device_id != kAudioObjectUnknown)
     stream = new AUAudioInputStream(this, params, audio_device_id);
 
   return stream;
 }
 
+void AudioManagerMac::InitializeOnAudioThread() {
+  listener_cb_ = BindToLoop(GetMessageLoop(), base::Bind(
+      &AudioManagerMac::NotifyAllOutputDeviceChangeListeners,
+      base::Unretained(this)));
+  output_device_listener_.reset(new AudioDeviceListenerMac(&listener_cb_));
+}
+
+void AudioManagerMac::DestructOnAudioThread() {
+  output_device_listener_.reset();
+}
+
 AudioManager* CreateAudioManager() {
   return new AudioManagerMac();
 }
 
 }  // namespace media