GitLab

Allows clients to implement the BatteryChargeStatusObserver interface
and register themselves as an observer in order to receive updates about
battery charge status.

Bug: 1128204
Change-Id: I7a6d87c44248de132e8318ca77a83ce20263df95
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2427424
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@{#812772}