Update GpsLocationProvider construction sequence to save time on startup.

b/20127262

This change moves long running operations: such as IO and broadcast receivers registration
to its internal handler. This sets the time to execute GpsLocationProvider ctor() to ~14ms.
A significant improvement from the 285ms reported originally in the bug.

Change-Id: I4ee4183a1afea86117004c0a052957b8bc1e4ce5