Ensures that audio tasks cannot run after AudioManager is deleted.

media/audio/audio_output_controller_unittest.cc

Index: media/audio/audio_output_controller_unittest.cc
diff --git a/media/audio/audio_output_controller_unittest.cc b/media/audio/audio_output_controller_unittest.cc
index 5b6d883085cd4c5ccc2b68fcd86e73acba73c47c..78b3ff03a67d1e3d7f1dc1e5909156fa0e0cb53d 100644
--- a/media/audio/audio_output_controller_unittest.cc
+++ b/media/audio/audio_output_controller_unittest.cc
@@ -116,7 +116,7 @@ class AudioOutputControllerTest : public testing::Test {
     base::RunLoop().RunUntilIdle();
   }
 
-  ~AudioOutputControllerTest() override {}
+  ~AudioOutputControllerTest() override { audio_manager_->Shutdown(); }
 
  protected:
   void Create(int samples_per_packet) {
@@ -277,7 +277,7 @@ class AudioOutputControllerTest : public testing::Test {
 
  private:
   base::TestMessageLoop message_loop_;
-  ScopedAudioManagerPtr audio_manager_;
+  std::unique_ptr<AudioManager> audio_manager_;
   MockAudioOutputControllerEventHandler mock_event_handler_;
   MockAudioOutputControllerSyncReader mock_sync_reader_;
   MockAudioOutputStream mock_stream_;