add buffering update to GenericSource

Bug: 17182378

Change-Id: Ib86f3f522d7ea635489edd2b512adb7f4b27e381
diff --git a/media/libmediaplayerservice/nuplayer/NuPlayerSource.h b/media/libmediaplayerservice/nuplayer/NuPlayerSource.h
index 74892b6..45657c2 100644
--- a/media/libmediaplayerservice/nuplayer/NuPlayerSource.h
+++ b/media/libmediaplayerservice/nuplayer/NuPlayerSource.h
@@ -45,6 +45,7 @@
         kWhatPrepared,
         kWhatFlagsChanged,
         kWhatVideoSizeChanged,
+        kWhatBufferingUpdate,
         kWhatBufferingStart,
         kWhatBufferingEnd,
         kWhatSubtitleData,