[chromecast] Bind and run mojo media services on cma thread.

chromecast/browser/media/cast_mojo_media_client.h

Index: chromecast/browser/media/cast_mojo_media_client.h
diff --git a/chromecast/browser/media/cast_mojo_media_client.h b/chromecast/browser/media/cast_mojo_media_client.h
index 9dcd6affb412d1d5ffb15c05818d8852a2eb085c..4dd02b0457a14b1e1c76ae89fc2ad2c3b59f05e4 100644
--- a/chromecast/browser/media/cast_mojo_media_client.h
+++ b/chromecast/browser/media/cast_mojo_media_client.h
@@ -13,7 +13,9 @@ namespace media {
 
 class CastMojoMediaClient : public ::media::MojoMediaClient {
  public:
-  CastMojoMediaClient(const CreateMediaPipelineBackendCB& create_backend_cb);
+  CastMojoMediaClient(
+      scoped_refptr<base::SingleThreadTaskRunner> media_task_runner,
+      const CreateMediaPipelineBackendCB& create_backend_cb);
   ~CastMojoMediaClient() override;
 
   // MojoMediaClient overrides.