commit 6246fad7ff75753ec984c1c008c25b9edc49b6ee
author jackqdyulei <jackqdyulei@google.com> Fri Apr 14 11:42:04 2017 -0700
committer jackqdyulei <jackqdyulei@google.com> Fri Apr 14 15:08:57 2017 -0700
tree 80023da3d8ae08c0ab14e14857e956f10b290577
parent c4f08120b10da944cf4dff0a0eab3477a8978a2e

Make battery status refresh in SettingsActivity

Before this cl, the battery text in SettingsActivity is one time
update, won't refresh based on real battery status.

This cl elicits BatteryBroadcastReceiver from PowerUsageBase and
make it reusable in both SettingsActivity and battery page.

BatteryBroadcastReceiver will invoke callback if:
1. Battery level changed on integer level(100->99)
2. Battery status has changed(i.e. charging)

Bug: 29346753
Test: RunSettingsRoboTests

Change-Id: If522d15a700ccbc8bae24f5712e05ec27ea4cbfa