GitLab

Allows clients to implement the BatteryHealthObserver interface and
register themselves as an observer in order to receive periodic updates
about the battery health.

Bug: 1128204
Change-Id: Ib4ffc60ec5fd30bda37c255bd17b669eaa4b9f74
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2438474
Commit-Queue: Bailey Berro <baileyberro@chromium.org>
Reviewed-by: Dominick Ng <dominickn@chromium.org>
Reviewed-by: Zentaro Kavanagh <zentaro@chromium.org>
Cr-Commit-Position: refs/heads/master@{#812822}