Ensures that audio tasks cannot run after AudioManager is deleted.

content/browser/renderer_host/media/audio_output_delegate_impl_unittest.cc

Index: content/browser/renderer_host/media/audio_output_delegate_impl_unittest.cc
diff --git a/content/browser/renderer_host/media/audio_output_delegate_impl_unittest.cc b/content/browser/renderer_host/media/audio_output_delegate_impl_unittest.cc
index 2d64eff6d9dddb2b76d9f34c0bb0990ac327264f..b3091e981637e0985546e7495ae7c400b8245378 100644
--- a/content/browser/renderer_host/media/audio_output_delegate_impl_unittest.cc
+++ b/content/browser/renderer_host/media/audio_output_delegate_impl_unittest.cc
@@ -120,6 +120,11 @@ class AudioOutputDelegateTest : public testing::Test {
     media_stream_manager_ =
         base::MakeUnique<MediaStreamManager>(audio_system_.get());
   }
+  ~AudioOutputDelegateTest() {
+    audio_manager_->GetTaskRunner()->PostTask(
+        FROM_HERE, base::Bind(&media::AudioManager::Shutdown,
+                              base::Unretained(audio_manager_.get())));
+  }
 
   // Test bodies are here, so that we can run them on the IO thread.
   void CreateTest(base::Closure done) {
@@ -450,8 +455,8 @@ class AudioOutputDelegateTest : public testing::Test {
   // TestBrowserThreadBundle.
   std::unique_ptr<MediaStreamManager> media_stream_manager_;
   std::unique_ptr<TestBrowserThreadBundle> thread_bundle_;
+  std::unique_ptr<media::AudioManager> audio_manager_;
   std::unique_ptr<AudioManagerThread> audio_thread_;
-  media::ScopedAudioManagerPtr audio_manager_;
   std::unique_ptr<media::AudioSystem> audio_system_;
   StrictMock<MockAudioMirroringManager> mirroring_manager_;
   StrictMock<MockEventHandler> event_handler_;