Ensures that audio tasks cannot run after AudioManager is deleted.

media/audio/cras/audio_manager_cras.cc

Index: media/audio/cras/audio_manager_cras.cc
diff --git a/media/audio/cras/audio_manager_cras.cc b/media/audio/cras/audio_manager_cras.cc
index a1d059e5ed91a60f43e365c800b32f247a8dfd68..875904a816c940df2b71e1eeac3f067044e71f27 100644
--- a/media/audio/cras/audio_manager_cras.cc
+++ b/media/audio/cras/audio_manager_cras.cc
@@ -134,21 +134,15 @@ bool AudioManagerCras::HasAudioInputDevices() {
   return false;
 }
 
-AudioManagerCras::AudioManagerCras(
-    scoped_refptr<base::SingleThreadTaskRunner> task_runner,
-    scoped_refptr<base::SingleThreadTaskRunner> worker_task_runner,
-    AudioLogFactory* audio_log_factory)
-    : AudioManagerBase(std::move(task_runner),
-                       std::move(worker_task_runner),
-                       audio_log_factory),
+AudioManagerCras::AudioManagerCras(std::unique_ptr<AudioThread> audio_thread,
+                                   AudioLogFactory* audio_log_factory)
+    : AudioManagerBase(std::move(audio_thread), 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();