google_battery: keep AC charging stats separate

Keeps AC charging stats separate from tier 2 charging statistics
and do not book elap time spent AC charging to the ttf stats.

Bug: 153043920
Test: regular charge cycle, dumped ttf stats
Test: AC charge cycle, dumped ttf stats
Signed-off-by: AleX Pelosi <[email protected]>
Change-Id: I827001752aeee36ad1a4fe6f74c85a346cd8e766
Signed-off-by: Ken Tsou <[email protected]>
(cherry picked from commit 08473a74a0383c739e3fb4b6bfeed2765828b63f)
3 files changed