CmaMediaPipelineClient to watch media pipeline status

chromecast/media/cma/pipeline/media_pipeline_client.h

Index: chromecast/media/cma/pipeline/media_pipeline_client.h
diff --git a/chromecast/media/cma/pipeline/media_pipeline_client.h b/chromecast/media/cma/pipeline/media_pipeline_client.h
index 692263c6e6a3306bbfc170fb75ff8899f2d6f9ea..1918ef17f2fc050144f4706ce51e1ddc49b4459a 100644
--- a/chromecast/media/cma/pipeline/media_pipeline_client.h
+++ b/chromecast/media/cma/pipeline/media_pipeline_client.h
@@ -29,6 +29,11 @@ struct MediaPipelineClient {
 
   // Callback used to report the buffering status.
   ::media::BufferingStateCB buffering_state_cb;
+
+  // Callback used to report the creation and destruction of
+  // MediaPipelineBackend
+  base::Closure pipeline_backend_created_cb;
+  base::Closure pipeline_backend_destroyed_cb;
 };
 
 }  // namespace media