Revert of Pass task runners to AudioManager constructor.

media/audio/win/audio_manager_win.h

Index: media/audio/win/audio_manager_win.h
diff --git a/media/audio/win/audio_manager_win.h b/media/audio/win/audio_manager_win.h
index 66b2426048335b0ade2b22af13d6bd0e8dbec8cf..583a98beb89fa5859d1178fecdcb9ae2551bc36d 100644
--- a/media/audio/win/audio_manager_win.h
+++ b/media/audio/win/audio_manager_win.h
@@ -19,10 +19,7 @@
 // the AudioManager class.
 class MEDIA_EXPORT AudioManagerWin : public AudioManagerBase {
  public:
-  AudioManagerWin(
-      scoped_refptr<base::SingleThreadTaskRunner> task_runner,
-      scoped_refptr<base::SingleThreadTaskRunner> worker_task_runner,
-      AudioLogFactory* audio_log_factory);
+  AudioManagerWin(AudioLogFactory* audio_log_factory);
 
   // Implementation of AudioManager.
   bool HasAudioOutputDevices() override;
@@ -88,6 +85,7 @@
   // Helper methods for performing expensive initialization tasks on the audio
   // thread instead of on the UI thread which AudioManager is constructed on.
   void InitializeOnAudioThread();
+  void ShutdownOnAudioThread();
 
   void GetAudioDeviceNamesImpl(bool input, AudioDeviceNames* device_names);