Added API to manage uids in each zone

Added API to set, get zones for each uid. Also added API to
request zone ids.

Bug: 121344631
Test: Though the api is not currently used I build and ran emulator and
everything continues to work as expected.

Change-Id: Iec2ffc7fa78936692ca32a9c8a2be02b0454b03e
5 files changed