Pass task runners to AudioManager constructor.

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 7183405a19063f1e44800336e1867ba7d4a9c733..dc650a16170831ca608dec4bc6ce98daed463ff1 100644
--- a/media/audio/mock_audio_manager.cc
+++ b/media/audio/mock_audio_manager.cc
@@ -12,7 +12,7 @@ namespace media {
 
 MockAudioManager::MockAudioManager(
     const scoped_refptr<base::SingleThreadTaskRunner>& task_runner)
-    : task_runner_(task_runner) {}
+    : AudioManager(task_runner, task_runner) {}
 
 MockAudioManager::~MockAudioManager() {
 }
@@ -63,15 +63,6 @@ media::AudioInputStream* MockAudioManager::MakeAudioInputStream(
   return NULL;
 }
 
-scoped_refptr<base::SingleThreadTaskRunner> MockAudioManager::GetTaskRunner() {
-  return task_runner_;
-}
-
-scoped_refptr<base::SingleThreadTaskRunner>
-MockAudioManager::GetWorkerTaskRunner() {
-  return task_runner_;
-}
-
 void MockAudioManager::AddOutputDeviceChangeListener(
     AudioDeviceListener* listener) {
 }