Pass task runners to AudioManager constructor.

media/mojo/services/mojo_media_client.h

Index: media/mojo/services/mojo_media_client.h
diff --git a/media/mojo/services/mojo_media_client.h b/media/mojo/services/mojo_media_client.h
index 4b55c9f9fac616a198750b1a51143ec7f8bf1e4d..95016413a497525063a35653c92a14c0ac734358 100644
--- a/media/mojo/services/mojo_media_client.h
+++ b/media/mojo/services/mojo_media_client.h
@@ -34,6 +34,10 @@ class MojoMediaClient {
 
   // Called exactly once before any other method.
   virtual void Initialize();
+  // Called before the host application is scheduled to quit.
+  // The application message loop is still valid at this point, so all clean
+  // up tasks requiring the message loop must be completed before returning.
+  virtual void WillQuit();
 
   virtual std::unique_ptr<AudioDecoder> CreateAudioDecoder(
       scoped_refptr<base::SingleThreadTaskRunner> task_runner);