Make AudioDebugFileWriter create its own file worker thread.

media/audio/audio_debug_recording_manager.h

 // Copyright 2017 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_DEBUG_RECORDING_MANAGER_H_
 #define MEDIA_AUDIO_AUDIO_DEBUG_RECORDING_MANAGER_H_
 
 #include <map>
 #include <memory>
 #include <string>
@@ skipping 43 matching lines @@
 // AudioManager::InitializeOutputDebugRecording() is called. That is done
 // in AudioManager::Create() in WebRTC enabled builds, but not in non WebRTC
 // enabled builds.
 // If AudioDebugRecordingManager is not created, neither is
 // AudioDebugRecordingHelper or AudioDebugFileWriter. In this case the pointers
 // to AudioDebugRecordingManager and AudioDebugRecordingHelper are null.
 //
 class MEDIA_EXPORT AudioDebugRecordingManager {
  public:
   AudioDebugRecordingManager(
-      scoped_refptr<base::SingleThreadTaskRunner> task_runner,
-      scoped_refptr<base::SingleThreadTaskRunner> file_task_runner);
+      scoped_refptr<base::SingleThreadTaskRunner> task_runner);
   virtual ~AudioDebugRecordingManager();
 
   // Enables and disables debug recording.
   virtual void EnableDebugRecording(const base::FilePath& base_file_name);
   virtual void DisableDebugRecording();
 
   // Registers a source and returns a wrapped recorder. |file_name_extension| is
   // added to the base filename, along with a unique running ID.
   std::unique_ptr<AudioDebugRecorder> RegisterDebugRecordingSource(
       const base::FilePath::StringType& file_name_extension,
       const AudioParameters& params);
 
  protected:
   // Creates a AudioDebugRecordingHelper. Overridden by test.
   virtual std::unique_ptr<AudioDebugRecordingHelper>
   CreateAudioDebugRecordingHelper(
       const AudioParameters& params,
       scoped_refptr<base::SingleThreadTaskRunner> task_runner,
-      scoped_refptr<base::SingleThreadTaskRunner> file_task_runner,
       base::OnceClosure on_destruction_closure);
 
   // The task runner this class lives on. Also handed to
   // AudioDebugRecordingHelpers.
   scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
 
  private:
   FRIEND_TEST_ALL_PREFIXES(AudioDebugRecordingManagerTest,
                            RegisterAutomaticUnregisterAtDelete);
   FRIEND_TEST_ALL_PREFIXES(AudioDebugRecordingManagerTest,
@@ skipping 11 matching lines @@
 
   bool IsDebugRecordingEnabled();
 
   // Recorders, one per source.
   DebugRecordingHelperMap debug_recording_helpers_;
 
   // The base file name for debug recording files. If this is non-empty, debug
   // recording is enabled.
   base::FilePath debug_recording_base_file_name_;
 
-  // Task runner that the file writer does file output operations on. Handed to
-  // AudioDebugRecordingHelpers
-  scoped_refptr<base::SingleThreadTaskRunner> file_task_runner_;
-
   base::WeakPtrFactory<AudioDebugRecordingManager> weak_factory_;
   DISALLOW_COPY_AND_ASSIGN(AudioDebugRecordingManager);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_AUDIO_AUDIO_DEBUG_RECORDING_MANAGER_H_