Map STATE_VR to STATE_ON for Battery Stats.

Also, sets STATE_VR to be a public API value for Android O release.

Test: Switch to VR mode, ensure "Unexpected screen state: 5" no
longer logs from BatteryStatsImpl
Bug: 35636815

Change-Id: I1f8be334967e1af1f92a3ed571c063e7b00106b1
6 files changed