Revert of Pass task runners to AudioManager constructor.

media/audio/win/audio_manager_win.cc

Index: media/audio/win/audio_manager_win.cc
diff --git a/media/audio/win/audio_manager_win.cc b/media/audio/win/audio_manager_win.cc
index df7faf452eae1c6b2112968396fc299647bb0fac..a3d5ead202f401e31f25c54713b657e7a02c48fb 100644
--- a/media/audio/win/audio_manager_win.cc
+++ b/media/audio/win/audio_manager_win.cc
@@ -126,19 +126,14 @@
   return (base::win::GetVersion() == base::win::VERSION_VISTA) ? 4 : 3;
 }
 
-AudioManagerWin::AudioManagerWin(
-    scoped_refptr<base::SingleThreadTaskRunner> task_runner,
-    scoped_refptr<base::SingleThreadTaskRunner> worker_task_runner,
-    AudioLogFactory* audio_log_factory)
-    : AudioManagerBase(std::move(task_runner),
-                       std::move(worker_task_runner),
-                       audio_log_factory),
+AudioManagerWin::AudioManagerWin(AudioLogFactory* audio_log_factory)
+    : AudioManagerBase(audio_log_factory),
       // |CoreAudioUtil::IsSupported()| uses static variables to avoid doing
       // multiple initializations.  This is however not thread safe.
       // So, here we call it explicitly before we kick off the audio thread
       // or do any other work.
-      enumeration_type_(CoreAudioUtil::IsSupported() ? kMMDeviceEnumeration
-                                                     : kWaveEnumeration) {
+      enumeration_type_(CoreAudioUtil::IsSupported() ?
+          kMMDeviceEnumeration : kWaveEnumeration) {
   SetMaxOutputStreamsAllowed(kMaxOutputStreams);
 
   // WARNING: This is executed on the UI loop, do not add any code here which
@@ -152,6 +147,10 @@
 }
 
 AudioManagerWin::~AudioManagerWin() {
+  // It's safe to post a task here since Shutdown() will wait for all tasks to
+  // complete before returning.
+  GetTaskRunner()->PostTask(FROM_HERE, base::Bind(
+      &AudioManagerWin::ShutdownOnAudioThread, base::Unretained(this)));
   Shutdown();
 }
 
@@ -173,6 +172,11 @@
         base::Bind(&AudioManagerWin::NotifyAllOutputDeviceChangeListeners,
                    base::Unretained(this)))));
   }
+}
+
+void AudioManagerWin::ShutdownOnAudioThread() {
+  DCHECK(GetTaskRunner()->BelongsToCurrentThread());
+  output_device_listener_.reset();
 }
 
 base::string16 AudioManagerWin::GetAudioInputDeviceModel() {
@@ -533,13 +537,8 @@
 }
 
 /// static
-ScopedAudioManagerPtr CreateAudioManager(
-    scoped_refptr<base::SingleThreadTaskRunner> task_runner,
-    scoped_refptr<base::SingleThreadTaskRunner> worker_task_runner,
-    AudioLogFactory* audio_log_factory) {
-  return ScopedAudioManagerPtr(
-      new AudioManagerWin(std::move(task_runner), std::move(worker_task_runner),
-                          audio_log_factory));
+AudioManager* CreateAudioManager(AudioLogFactory* audio_log_factory) {
+  return new AudioManagerWin(audio_log_factory);
 }
 
 }  // namespace media