Make AudioDebugFileWriter create its own file worker thread.

media/audio/audio_manager.h

 // Copyright (c) 2012 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 MEDIA_AUDIO_AUDIO_MANAGER_H_
 #define MEDIA_AUDIO_AUDIO_MANAGER_H_
 
 #include <memory>
 #include <string>
 
@@ skipping 183 matching lines @@
  protected:
   FRIEND_TEST_ALL_PREFIXES(AudioManagerTest, AudioDebugRecording);
   friend class AudioDeviceInfoAccessorForTests;
 
   explicit AudioManager(std::unique_ptr<AudioThread> audio_thread);
 
   virtual void ShutdownOnAudioThread() = 0;
 
   // Initializes output debug recording. Can be called on any thread; will post
   // to the audio thread if not called on it.
-  virtual void InitializeOutputDebugRecording(
-      scoped_refptr<base::SingleThreadTaskRunner> file_task_runner) = 0;
+  virtual void InitializeOutputDebugRecording() = 0;
 
   // Returns true if the OS reports existence of audio devices. This does not
   // guarantee that the existing devices support all formats and sample rates.
   virtual bool HasAudioOutputDevices() = 0;
 
   // Returns true if the OS reports existence of audio recording devices. This
   // does not guarantee that the existing devices support all formats and
   // sample rates.
   virtual bool HasAudioInputDevices() = 0;
 
@@ skipping 58 matching lines @@
   std::unique_ptr<AudioThread> audio_thread_;
   bool shutdown_ = false;  // True after |this| has been shutdown.
 
   THREAD_CHECKER(thread_checker_);
   DISALLOW_COPY_AND_ASSIGN(AudioManager);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_AUDIO_AUDIO_MANAGER_H_