battery charge indicator not updating unless there's a power event

[kevin gunn]

Witness this on build 163 trusty on Manta/Nexus10

Battery was low (low enough to color red)
Left on the appropriate charger overnight (the OEM charger)
In the morning - woke the device, navigated about the ui, including pulling down the indicator panel
the battery status remained red & reflected 0% charge in the panel.
 (this took some time..long enough to freak and ask others if they had charging issues on manta on irc)
The moment I unplugged the device from the charger, the ui corrected to reflect full battery icon along with 100% charge
i suspect there needs to be a read of the status on the wake event at least