Misc fixes for throttling.

Cleanup of duplicate code
Caching Ntp data so we don't hit the network as often
Clearing out of MRU data when we switch to a new sim
Sending notification after we reset byte counts

bug:2605277
bug:2605272
bug:2597530
bug:2576057
Change-Id: I3df526bae6374f6ae56fed67b0defad2b4fabefd