Revert of Pass task runners to AudioManager constructor.

media/audio/android/audio_manager_android.h

Index: media/audio/android/audio_manager_android.h
diff --git a/media/audio/android/audio_manager_android.h b/media/audio/android/audio_manager_android.h
index 22b48c82173d9627251e103c30a613a671c4e92c..f9b7db253498d42185c671d2d48d29e7b8484579 100644
--- a/media/audio/android/audio_manager_android.h
+++ b/media/audio/android/audio_manager_android.h
@@ -20,10 +20,7 @@
 // Android implemention of AudioManager.
 class MEDIA_EXPORT AudioManagerAndroid : public AudioManagerBase {
  public:
-  AudioManagerAndroid(
-      scoped_refptr<base::SingleThreadTaskRunner> task_runner,
-      scoped_refptr<base::SingleThreadTaskRunner> worker_task_runner,
-      AudioLogFactory* audio_log_factory);
+  explicit AudioManagerAndroid(AudioLogFactory* audio_log_factory);
 
   // Implementation of AudioManager.
   bool HasAudioOutputDevices() override;
@@ -74,6 +71,7 @@
 
  private:
   void InitializeOnAudioThread();
+  void ShutdownOnAudioThread();
 
   bool HasNoAudioInputStreams();
   void SetCommunicationAudioModeOn(bool on);