Ensures that audio tasks cannot run after AudioManager is deleted.

media/audio/mac/audio_manager_mac.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/mac/audio_manager_mac.h"
 
 #include <algorithm>
 #include <limits>
 #include <vector>
 
@@ skipping 400 matching lines @@
   SetMaxOutputStreamsAllowed(kMaxOutputStreams);
 
   // Task must be posted last to avoid races from handing out "this" to the
   // audio thread.  Always PostTask even if we're on the right thread since
   // AudioManager creation is on the startup path and this may be slow.
   GetTaskRunner()->PostTask(
       FROM_HERE, base::Bind(&AudioManagerMac::InitializeOnAudioThread,
                             base::Unretained(this)));
 }
 
-AudioManagerMac::~AudioManagerMac() {
-  DCHECK(GetTaskRunner()->BelongsToCurrentThread());
+AudioManagerMac::~AudioManagerMac() = default;
+
+void AudioManagerMac::Shutdown() {
   // We are now in shutdown mode. This flag disables MaybeChangeBufferSize()
   // and IncreaseIOBufferSizeIfPossible() which both touches native Core Audio
   // APIs and they can fail and disrupt tests during shutdown.
   in_shutdown_ = true;
-  Shutdown();
+  AudioManagerBase::Shutdown();
 }
 
 bool AudioManagerMac::HasAudioOutputDevices() {
   return HasAudioHardware(kAudioHardwarePropertyDefaultOutputDevice);
 }
 
 bool AudioManagerMac::HasAudioInputDevices() {
   return HasAudioHardware(kAudioHardwarePropertyDefaultInputDevice);
 }
 
@@ skipping 720 matching lines @@
                              basic_input_streams_.end(),
                              stream);
   if (stream_it == basic_input_streams_.end())
     low_latency_input_streams_.remove(static_cast<AUAudioInputStream*>(stream));
   else
     basic_input_streams_.erase(stream_it);
 
   AudioManagerBase::ReleaseInputStream(stream);
 }
 
-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 AudioManagerMac(std::move(task_runner), std::move(worker_task_runner),
-                          audio_log_factory));
+  return base::MakeUnique<AudioManagerMac>(
+      std::move(task_runner), std::move(worker_task_runner), audio_log_factory);
 }
 
 }  // namespace media