healthd: Set fixed battery level and temperature via properties

setprop persist.sys.battery.capacity 77
setprop persist.sys.battery.temperature 123

and reboot to cause a fixed battery level of 77% and temperature of 12.3C
to be reported to Android.

Typically used on power evaluation boards without batteries connected.

Bug: 14839868
Change-Id: Ibae5e16429d05891cb0787d74a2fe93b07013699
diff --git a/healthd/BatteryMonitor.h b/healthd/BatteryMonitor.h
index 4866cc2..3425f27 100644
--- a/healthd/BatteryMonitor.h
+++ b/healthd/BatteryMonitor.h
@@ -46,6 +46,8 @@
     struct healthd_config *mHealthdConfig;
     Vector<String8> mChargerNames;
     bool mBatteryDevicePresent;
+    int mBatteryFixedCapacity;
+    int mBatteryFixedTemperature;
     struct BatteryProperties props;
 
     int getBatteryStatus(const char* status);