Revert of Pass task runners to AudioManager constructor.

chromecast/media/audio/cast_audio_manager_factory.h

 // Copyright 2015 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.
 
 #ifndef CHROMECAST_MEDIA_AUDIO_CAST_AUDIO_MANAGER_FACTORY_H_
 #define CHROMECAST_MEDIA_AUDIO_CAST_AUDIO_MANAGER_FACTORY_H_
 
 #include "base/macros.h"
 #include "media/audio/audio_manager_factory.h"
 
 namespace chromecast {
 namespace media {
 
 class MediaPipelineBackendManager;
 
 class CastAudioManagerFactory : public ::media::AudioManagerFactory {
  public:
   explicit CastAudioManagerFactory(
       MediaPipelineBackendManager* backend_manager);
   ~CastAudioManagerFactory() override;
 
   // ::media::AudioManagerFactory overrides.
-  scoped_ptr<::media::AudioManager, ::media::AudioManagerDeleter>
-  CreateInstance(scoped_refptr<base::SingleThreadTaskRunner> task_runner,
-                 scoped_refptr<base::SingleThreadTaskRunner> worker_task_runner,
-                 ::media::AudioLogFactory* audio_log_factory) override;
+  ::media::AudioManager* CreateInstance(
+      ::media::AudioLogFactory* audio_log_factory) override;
 
  private:
   MediaPipelineBackendManager* const backend_manager_;
 
   DISALLOW_COPY_AND_ASSIGN(CastAudioManagerFactory);
 };
 
 }  // namespace media
 }  // namespace chromecast
 
 #endif  // CHROMECAST_MEDIA_AUDIO_CAST_AUDIO_MANAGER_FACTORY_H_