Ensures that audio tasks cannot run after AudioManager is deleted.

media/audio/mock_audio_manager.cc

Index: media/audio/mock_audio_manager.cc
diff --git a/media/audio/mock_audio_manager.cc b/media/audio/mock_audio_manager.cc
index b89cb5e1a8f89179670b8b7126f42e18352ade25..da24d323fda181a10d9508bbf7ea26c2c68d3524 100644
--- a/media/audio/mock_audio_manager.cc
+++ b/media/audio/mock_audio_manager.cc
@@ -11,19 +11,6 @@
 
 namespace media {
 
-void MockAudioManager::Deleter::operator()(
-    const MockAudioManager* instance) const {
-  CHECK(instance);
-  if (instance->GetTaskRunner()->BelongsToCurrentThread()) {
-    delete instance;
-    return;
-  }
-  // AudioManager must be destroyed on the audio thread.
-  if (!instance->GetTaskRunner()->DeleteSoon(FROM_HERE, instance)) {
-    LOG(WARNING) << "Failed to delete AudioManager instance.";
-  }
-}
-
 MockAudioManager::MockAudioManager(
     scoped_refptr<base::SingleThreadTaskRunner> task_runner)
     : AudioManager(task_runner, task_runner) {}
@@ -31,6 +18,8 @@ MockAudioManager::MockAudioManager(
 MockAudioManager::~MockAudioManager() {
 }
 
+void MockAudioManager::Shutdown() {}
+
 bool MockAudioManager::HasAudioOutputDevices() {
   DCHECK(GetTaskRunner()->BelongsToCurrentThread());
   return has_output_devices_;