libbatteryservice: add interface to read individual battery properties

Change-Id: I089eb6348053a8a9c8bca59e57ed97b4af14825a
diff --git a/services/batteryservice/Android.mk b/services/batteryservice/Android.mk
index 0a29c36..9354b99 100644
--- a/services/batteryservice/Android.mk
+++ b/services/batteryservice/Android.mk
@@ -3,6 +3,7 @@
 
 LOCAL_SRC_FILES:= \
 	BatteryProperties.cpp \
+	BatteryProperty.cpp \
 	IBatteryPropertiesListener.cpp \
 	IBatteryPropertiesRegistrar.cpp