Ensures that audio tasks cannot run after AudioManager is deleted.

content/browser/renderer_host/media/audio_output_authorization_handler_unittest.cc

Index: content/browser/renderer_host/media/audio_output_authorization_handler_unittest.cc
diff --git a/content/browser/renderer_host/media/audio_output_authorization_handler_unittest.cc b/content/browser/renderer_host/media/audio_output_authorization_handler_unittest.cc
index c6631d2cd5595493b79b09727cb1344d294d5058..a15752aeb59dadb91059d713ca7df0291675df44 100644
--- a/content/browser/renderer_host/media/audio_output_authorization_handler_unittest.cc
+++ b/content/browser/renderer_host/media/audio_output_authorization_handler_unittest.cc
@@ -74,7 +74,12 @@ class AudioOutputAuthorizationHandlerTest : public testing::Test {
     SyncWithAllThreads();
   }
 
-  ~AudioOutputAuthorizationHandlerTest() override { SyncWithAllThreads(); }
+  ~AudioOutputAuthorizationHandlerTest() override {
+    audio_manager_->GetTaskRunner()->PostTask(
+        FROM_HERE, base::Bind(&media::AudioManager::Shutdown,
+                              base::Unretained(audio_manager_.get())));
+    SyncWithAllThreads();
+  }
 
  protected:
   MediaStreamManager* GetMediaStreamManager() {
@@ -139,10 +144,10 @@ class AudioOutputAuthorizationHandlerTest : public testing::Test {
   // DestructionObserver.
   std::unique_ptr<MediaStreamManager> media_stream_manager_;
   std::unique_ptr<TestBrowserThreadBundle> thread_bundle_;
-  std::unique_ptr<AudioManagerThread> audio_thread_;
   media::FakeAudioLogFactory log_factory_;
-  media::ScopedAudioManagerPtr audio_manager_;
+  std::unique_ptr<media::AudioManager> audio_manager_;
   std::unique_ptr<media::AudioSystem> audio_system_;
+  std::unique_ptr<AudioManagerThread> audio_thread_;
 
   DISALLOW_COPY_AND_ASSIGN(AudioOutputAuthorizationHandlerTest);
 };