Make AudioDebugFileWriter create its own file worker thread.

media/audio/audio_manager.cc

 // 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.
 
 #include "media/audio/audio_manager.h"
 
 #include <stdint.h>
 
 #include <utility>
 
@@ skipping 263 matching lines @@
   } else {
     // We create multiple instances of AudioManager only when testing.
     // We should not encounter this case in production.
     LOG(WARNING) << "Multiple instances of AudioManager detected";
   }
 }
 
 // static
 std::unique_ptr<AudioManager> AudioManager::Create(
     std::unique_ptr<AudioThread> audio_thread,
-    scoped_refptr<base::SingleThreadTaskRunner> file_task_runner,
     AudioLogFactory* audio_log_factory) {
   std::unique_ptr<AudioManager> manager =
       CreateAudioManager(std::move(audio_thread), audio_log_factory);
 #if BUILDFLAG(ENABLE_WEBRTC)
-  manager->InitializeOutputDebugRecording(std::move(file_task_runner));
+  manager->InitializeOutputDebugRecording();
 #endif
   return manager;
 }
 
 // static
 std::unique_ptr<AudioManager> AudioManager::CreateForTesting(
     std::unique_ptr<AudioThread> audio_thread) {
 #if defined(OS_WIN)
   GetHelper()->InitializeCOMForTesting();
 #endif
-  scoped_refptr<base::SingleThreadTaskRunner> file_task_runner =
-      audio_thread->GetWorkerTaskRunner();
-  return Create(std::move(audio_thread), std::move(file_task_runner),
-                GetHelper()->fake_log_factory());
+  return Create(std::move(audio_thread), GetHelper()->fake_log_factory());
 }
 
 // static
 void AudioManager::StartHangMonitorIfNeeded(
     scoped_refptr<base::SingleThreadTaskRunner> task_runner) {
   if (GetHelper()->monitor_task_runner())
     return;
 
   DCHECK(AudioManager::Get());
   DCHECK(task_runner);
@@ skipping 29 matching lines @@
   } else {
     audio_thread_->GetTaskRunner()->PostTask(
         FROM_HERE, base::Bind(&AudioManager::ShutdownOnAudioThread,
                               base::Unretained(this)));
   }
   audio_thread_->Stop();
   shutdown_ = true;
 }
 
 }  // namespace media