Ensures that audio tasks cannot run after AudioManager is deleted.

media/audio/cras/audio_manager_cras.cc

 // Copyright 2013 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/cras/audio_manager_cras.h"
 
 #include <stddef.h>
 
 #include <algorithm>
 
@@ skipping 124 matching lines @@
     scoped_refptr<base::SingleThreadTaskRunner> worker_task_runner,
     AudioLogFactory* audio_log_factory)
     : AudioManagerBase(std::move(task_runner),
                        std::move(worker_task_runner),
                        audio_log_factory),
       beamforming_on_device_id_(nullptr),
       beamforming_off_device_id_(nullptr) {
   SetMaxOutputStreamsAllowed(kMaxOutputStreams);
 }
 
-AudioManagerCras::~AudioManagerCras() {
-  Shutdown();
-}
+AudioManagerCras::~AudioManagerCras() = default;
 
 void AudioManagerCras::ShowAudioInputSettings() {
   NOTIMPLEMENTED();
 }
 
 void AudioManagerCras::GetAudioDeviceNamesImpl(bool is_input,
                                                AudioDeviceNames* device_names) {
   DCHECK(device_names->empty());
   // At least two mic positions indicates we have a beamforming capable mic
   // array. Add the virtual beamforming device to the list. When this device is
@@ skipping 159 matching lines @@
 
 bool AudioManagerCras::IsDefault(const std::string& device_id, bool is_input) {
   AudioDeviceNames device_names;
   GetAudioDeviceNamesImpl(is_input, &device_names);
   DCHECK(!device_names.empty());
   const AudioDeviceName& device_name = device_names.front();
   return device_name.unique_id == device_id;
 }
 
 }  // namespace media