Ensures that audio tasks cannot run after AudioManager is deleted.

media/audio/android/audio_manager_android.cc

Index: media/audio/android/audio_manager_android.cc
diff --git a/media/audio/android/audio_manager_android.cc b/media/audio/android/audio_manager_android.cc
index 502a8cbf8dc84955a99546cfabc3858b164e0e4e..70b7ea39796adf73b2ef5b4b1b9f06b42f2e0ee8 100644
--- a/media/audio/android/audio_manager_android.cc
+++ b/media/audio/android/audio_manager_android.cc
@@ -46,13 +46,12 @@ const int kDefaultOutputBufferSize = 2048;
 
 }  // namespace
 
-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 AudioManagerAndroid(
-      std::move(task_runner), std::move(worker_task_runner),
-      audio_log_factory));
+  return base::MakeUnique<AudioManagerAndroid>(
+      std::move(task_runner), std::move(worker_task_runner), audio_log_factory);
 }
 
 AudioManagerAndroid::AudioManagerAndroid(
@@ -68,17 +67,7 @@ AudioManagerAndroid::AudioManagerAndroid(
   SetMaxOutputStreamsAllowed(kMaxOutputStreams);
 }
 
-AudioManagerAndroid::~AudioManagerAndroid() {
-  DCHECK(GetTaskRunner()->BelongsToCurrentThread());
-  Shutdown();
-
-  if (j_audio_manager_.is_null())
-    return;
-  DVLOG(2) << "Destroying Java part of the audio manager";
-  Java_AudioManagerAndroid_close(base::android::AttachCurrentThread(),
-                                 j_audio_manager_);
-  j_audio_manager_.Reset();
-}
+AudioManagerAndroid::~AudioManagerAndroid() = default;
 
 void AudioManagerAndroid::InitializeIfNeeded() {
   GetTaskRunner()->PostTask(
@@ -87,6 +76,17 @@ void AudioManagerAndroid::InitializeIfNeeded() {
                  base::Unretained(this)));
 }
 
+void AudioManagerAndroid::Shutdown() {
+  AudioManagerBase::Shutdown();
+
+  if (!j_audio_manager_.is_null()) {
+    DVLOG(2) << "Destroying Java part of the audio manager";
+    Java_AudioManagerAndroid_close(base::android::AttachCurrentThread(),
+                                   j_audio_manager_);
+    j_audio_manager_.Reset();
+  }
+}
+
 bool AudioManagerAndroid::HasAudioOutputDevices() {
   return true;
 }