Statsd atoms: BatteryVoltage

Add battery voltage to statsd as a pulled atom.

Bug: 114451845
Test: run cts-dev -m CtsStatsdHostTestCases -t android.cts.statsd.atom.HostAtomTests#testBatteryVoltage

Change-Id: If40ed41663b57ad6144c69c52c4c63562f93c774
diff --git a/cmds/statsd/src/atoms.proto b/cmds/statsd/src/atoms.proto
index 2c07431..6fe9177 100644
--- a/cmds/statsd/src/atoms.proto
+++ b/cmds/statsd/src/atoms.proto
@@ -167,6 +167,7 @@
         AppSize app_size = 10027;
         CategorySize category_size = 10028;
         android.service.procstats.ProcessStatsSectionProto proc_stats = 10029;
+        BatteryVoltage battery_voltage = 10030;
     }
 
     // DO NOT USE field numbers above 100,000 in AOSP. Field numbers above
@@ -2155,6 +2156,16 @@
 }
 
 /**
+ * Pulls battery voltage.
+ * Pulled from:
+ *   frameworks/base/cmds/statsd/src/external/ResourceHealthManagerPuller.cpp
+ */
+message BatteryVoltage {
+    // The voltage of the battery, in millivolts.
+    optional int32 voltage_mV = 1;
+}
+
+/**
  * Pulls the temperature of various parts of the device.
  * The units are tenths of a degree Celsius. Eg: 30.3C is reported as 303.
  *