healthd: BatteryService dumpstate support

Change-Id: Ia6938b7126751801310632c995af0f96e41f5f64
diff --git a/healthd/healthd.cpp b/healthd/healthd.cpp
index 66b961d..095ce9d 100644
--- a/healthd/healthd.cpp
+++ b/healthd/healthd.cpp
@@ -195,6 +195,11 @@
                 -1 : healthd_config.periodic_chores_interval_fast * 1000;
 }
 
+void healthd_dump_battery_state(int fd) {
+    gBatteryMonitor->dumpState(fd);
+    fsync(fd);
+}
+
 static void periodic_chores() {
     healthd_battery_update();
 }