Make sure we get to discover that the cache is sufficiently full again

by posting buffering events while in the CACHE_UNDERRUN state.

Change-Id: Ic60c8d57f0ae502aa2b6eec7160dc4224b989604
related-to-bug: 11262689
diff --git a/media/libstagefright/AwesomePlayer.cpp b/media/libstagefright/AwesomePlayer.cpp
index c912f75..52bd896 100644
--- a/media/libstagefright/AwesomePlayer.cpp
+++ b/media/libstagefright/AwesomePlayer.cpp
@@ -798,7 +798,7 @@
         }
     }
 
-    if (mFlags & (PLAYING | PREPARING)) {
+    if (mFlags & (PLAYING | PREPARING | CACHE_UNDERRUN)) {
         postBufferingEvent_l();
     }
 }