Ensures that audio tasks cannot run after AudioManager is deleted.

media/audio/win/audio_manager_win.cc

Index: media/audio/win/audio_manager_win.cc
diff --git a/media/audio/win/audio_manager_win.cc b/media/audio/win/audio_manager_win.cc
index 119ac3a2f4a2f078ce44135e499de67498f46a57..66a805d9d26ac5141ed692aad32c18935d857474 100644
--- a/media/audio/win/audio_manager_win.cc
+++ b/media/audio/win/audio_manager_win.cc
@@ -157,8 +157,11 @@ AudioManagerWin::AudioManagerWin(
                             base::Unretained(this)));
 }
 
-AudioManagerWin::~AudioManagerWin() {
-  Shutdown();
+AudioManagerWin::~AudioManagerWin() = default;
+
+void AudioManagerWin::Shutdown() {
+  AudioManagerBase::Shutdown();
+  output_device_listener_.reset();
 }
 
 bool AudioManagerWin::HasAudioOutputDevices() {
@@ -464,13 +467,12 @@ AudioParameters AudioManagerWin::GetPreferredOutputStreamParameters(
 }
 
 // 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