Counts may differ from user perception. For example, if notifications arrive
after the shade is open (even if it is only peeking) there will not be another
panel_reveal before the user sees the shade. User perception is more accurately
measured by visibility events.
Peek events will report the notificaiton load as 1.
Bug: 20088581
Change-Id: I10221d4b66a18c223aae21e616615f087c65b1e1
b659c4f44a