Use the existing PointerEventListener infrastructure to listen for
gestures that look like flings and hint to the power system when they
happen. Since we don't actually have a bound for the fling like a
regular application would, limit them to five seconds and refresh
every time a new fling is seen until the five second time period is
up.
bug 24059298
Change-Id: I5757a1e88f2ab2ef08cccefa8221d809ae71bb6f
a4d22d718a