Fix issue #3074745: Crash in system process

Also some tweaks to battery history collection to hopefully
improve the data we have.

Change-Id: I178a54a8c2d15cf38dcceaeef939406f50059aa4
diff --git a/core/java/android/os/BatteryStats.java b/core/java/android/os/BatteryStats.java
index d49c8be..d67e6f5 100644
--- a/core/java/android/os/BatteryStats.java
+++ b/core/java/android/os/BatteryStats.java
@@ -449,6 +449,10 @@
         public static final int STATE_WAKE_LOCK_FLAG = 1<<17;
         public static final int STATE_SENSOR_ON_FLAG = 1<<16;
         
+        public static final int MOST_INTERESTING_STATES =
+            STATE_BATTERY_PLUGGED_FLAG | STATE_SCREEN_ON_FLAG
+            | STATE_GPS_ON_FLAG | STATE_PHONE_IN_CALL_FLAG;
+
         public int states;
 
         public HistoryItem() {