Ensures that audio tasks cannot run after AudioManager is deleted.

media/audio/win/audio_manager_win.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/win/audio_manager_win.h"
 
 #include <windows.h>
 #include <objbase.h>  // This has to be before initguid.h
 #include <initguid.h>
 #include <mmsystem.h>
@@ skipping 139 matching lines @@
   // loads libraries or attempts to call out into the OS.  Instead add such code
   // to the InitializeOnAudioThread() method below.
 
   // Task must be posted last to avoid races from handing out "this" to the
   // audio thread.
   GetTaskRunner()->PostTask(
       FROM_HERE, base::Bind(&AudioManagerWin::InitializeOnAudioThread,
                             base::Unretained(this)));
 }
 
-AudioManagerWin::~AudioManagerWin() {
-  Shutdown();
+AudioManagerWin::~AudioManagerWin() = default;
+
+void AudioManagerWin::Shutdown() {
+  AudioManagerBase::Shutdown();
+  output_device_listener_.reset();
 }
 
 bool AudioManagerWin::HasAudioOutputDevices() {
   return (::waveOutGetNumDevs() != 0);
 }
 
 bool AudioManagerWin::HasAudioInputDevices() {
   return (::waveInGetNumDevs() != 0);
 }
 
@@ skipping 285 matching lines @@
   if (user_buffer_size)
     buffer_size = user_buffer_size;
 
   AudioParameters params(AudioParameters::AUDIO_PCM_LOW_LATENCY, channel_layout,
                          sample_rate, bits_per_sample, buffer_size);
   params.set_effects(effects);
   return params;
 }
 
 // static
-ScopedAudioManagerPtr CreateAudioManager(
+std::unique_ptr<AudioManager> CreateAudioManager(
     scoped_refptr<base::SingleThreadTaskRunner> task_runner,
     scoped_refptr<base::SingleThreadTaskRunner> worker_task_runner,
     AudioLogFactory* audio_log_factory) {
-  return ScopedAudioManagerPtr(
-      new AudioManagerWin(std::move(task_runner), std::move(worker_task_runner),
-                          audio_log_factory));
+  return base::MakeUnique<AudioManagerWin>(
+      std::move(task_runner), std::move(worker_task_runner), audio_log_factory);
 }
 
 }  // namespace media