Make AudioDebugFileWriter create its own file worker thread.

media/audio/audio_manager_base.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_BASE_H_
 #define MEDIA_AUDIO_AUDIO_MANAGER_BASE_H_
 
 #include <memory>
 #include <string>
 #include <unordered_set>
@@ skipping 134 matching lines @@
   // Appends a list of available output devices to |device_names|,
   // which must initially be empty.
   virtual void GetAudioOutputDeviceNames(AudioDeviceNames* device_names);
 
   // Returns the ID of the default audio output device.
   // Implementations that don't yet support this should return an empty string.
   virtual std::string GetDefaultOutputDeviceID();
 
   virtual std::unique_ptr<AudioDebugRecordingManager>
   CreateAudioDebugRecordingManager(
-      scoped_refptr<base::SingleThreadTaskRunner> task_runner,
-      scoped_refptr<base::SingleThreadTaskRunner> file_task_runner);
+      scoped_refptr<base::SingleThreadTaskRunner> task_runner);
 
  private:
   FRIEND_TEST_ALL_PREFIXES(AudioManagerTest, AudioDebugRecording);
 
   struct DispatcherParams;
   typedef std::vector<std::unique_ptr<DispatcherParams>> AudioOutputDispatchers;
 
   class CompareByParams;
 
   // AudioManager:
-  void InitializeOutputDebugRecording(
-      scoped_refptr<base::SingleThreadTaskRunner> file_task_runner) final;
+  void InitializeOutputDebugRecording() final;
 
   // These functions assign group ids to devices based on their device ids.
   // The default implementation is an attempt to do this based on
   // GetAssociatedOutputDeviceID. Must be called on the audio worker thread
   // (see GetTaskRunner()).
   std::string GetGroupIDOutput(const std::string& output_device_id);
   std::string GetGroupIDInput(const std::string& input_device_id);
 
   // Max number of open output streams, modified by
   // SetMaxOutputStreamsAllowed().
@@ skipping 20 matching lines @@
 
   // Debug recording manager.
   std::unique_ptr<AudioDebugRecordingManager> debug_recording_manager_;
 
   DISALLOW_COPY_AND_ASSIGN(AudioManagerBase);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_AUDIO_AUDIO_MANAGER_BASE_H_