am 58e0eefe: Improve power tracking of WIFI use.

Merge commit '58e0eefeb5e2e270e2b04369bbf29fc22abda8d5' into gingerbread-plus-aosp

* commit '58e0eefeb5e2e270e2b04369bbf29fc22abda8d5':
  Improve power tracking of WIFI use.