This replaces the ACCURACY_METERS constant and all derived values with
a secure setting. This value defaults to 2km and has a hardcoded floor
of 500m.
Bug: 6982024
Change-Id: Ibf97ab57145abf28c4a9747444f40250adddf23c
Fix a couple of bugs, and modify the behavior of the random offset.
The random offset now slowly changes over time, to mitigate against
applications averaging out the offset over time while at a
grid boundary.
Change-Id: Iecffff29145b8c2b30d1eca1662cf9d3e8cff756