healthd: read individual battery property value on demand

Adding support for batteryChargeCounter and batteryCurrentNow as parameters
likely to be useful for power consumption analysis.

Change-Id: Ib23b05d3c31c22ece0d21e55cc481c1b5dabe59e
diff --git a/healthd/BatteryPropertiesRegistrar.h b/healthd/BatteryPropertiesRegistrar.h
index 793ddad..0ce6c04 100644
--- a/healthd/BatteryPropertiesRegistrar.h
+++ b/healthd/BatteryPropertiesRegistrar.h
@@ -44,6 +44,7 @@
 
     void registerListener(const sp<IBatteryPropertiesListener>& listener);
     void unregisterListener(const sp<IBatteryPropertiesListener>& listener);
+    status_t getProperty(int id, struct BatteryProperty *val);
     void binderDied(const wp<IBinder>& who);
 };