Repeat ringtones every 3 seconds.

This repeats ringtones at multiples of 3 seconds.  E.g., if the ringtone
is 2 seconds long it will repeat every 3 seconds, if it is 4 secs long
it will repeat every 6 seconds, if it is 7 secs long, it repeats every
9...you get the picture.

Bug: 17466554
Change-Id: I4cad6d03b92cde7d5d1652fc91834c7499c2960a