Handle audio device changes on Mac

media/audio/mac/audio_manager_mac.cc

Index: media/audio/mac/audio_manager_mac.cc
diff --git a/media/audio/mac/audio_manager_mac.cc b/media/audio/mac/audio_manager_mac.cc
index a0562837d43ec7fbb82a408e7e5826b5e675505b..ca9485503e44d61a47dd8f535689d9460251d412 100644
--- a/media/audio/mac/audio_manager_mac.cc
+++ b/media/audio/mac/audio_manager_mac.cc
@@ -6,10 +6,12 @@
 
 #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"
@@ -17,6 +19,7 @@
 #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"
 
@@ -235,6 +238,10 @@ AudioManagerMac::AudioManagerMac() {
 }
 
 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();
 }
 
@@ -305,6 +312,17 @@ AudioInputStream* AudioManagerMac::MakeLowLatencyInputStream(
   return stream;
 }
 
+void AudioManagerMac::InitializeOnAudioThread() {
+  output_device_listener_.reset(new AudioDeviceListenerMac(BindToLoop(
+      GetMessageLoop(),
+      base::Bind(&AudioManagerMac::NotifyAllOutputDeviceChangeListeners,
+                 base::Unretained(this)))));
+}
+
+void AudioManagerMac::DestructOnAudioThread() {
+  output_device_listener_.reset();
+}
+
 AudioManager* CreateAudioManager() {
   return new AudioManagerMac();
 }