BufferingSettings: define internal BufferingSettings API.

Test: compiles
Bug: 32524218
Change-Id: I9a95b2fdfa497179305e031aac69e5a987614dbb
diff --git a/media/libmedia/Android.mk b/media/libmedia/Android.mk
index 2e4cf7d..f4d8bc0 100644
--- a/media/libmedia/Android.mk
+++ b/media/libmedia/Android.mk
@@ -12,6 +12,7 @@
 LOCAL_SRC_FILES += \
     IDataSource.cpp \
     IHDCP.cpp \
+    BufferingSettings.cpp \
     mediaplayer.cpp \
     IMediaCodecList.cpp \
     IMediaCodecService.cpp \