base

collect more stats about the notification API

3.5 times as many bytes, at 1/4th the frequency, so a net reduction
in log size, although it'll seem like an increase due to being bursty
and therefore more noticable.

Bug: 21530763
Change-Id: Icb1a1a1b0dcd4fd8b3c24f317d39b38f1591757e