Keep track of discharge while screen is on vs. off.
Checkin looks like:
5,0,u,dc,1,1,1,0
The last four numbers are, from left:
- Maximum battery drain over time period.
- Minimum battery drain over time period.
- Battery drain while screen was on.
- Battery drain while screen was off.
Change-Id: Ie4026a7cc8aabb2a6d47d03d2e278aa51c2d5ddf