Merge changes Ia68f482a,I4911e214,Ied379654,I66d18512,Ie8e1bd63

* changes:
  Check registering system default callback needs NETWORK_SETTINGS.
  Move VPN code from ConnectivityService to VpnManagerService.
  Add a skeleton VpnManagerService, and start it on boot.
  Convert LockdownVpnTracker to NetworkCallbacks.
  Minor fixes to VpnTransportInfo.
tree: 1829860251f0e191b3c9f7ce7b30e0534aec5367
  1. core/
  2. framework/
  3. service/
  4. services/
  5. tests/
  6. OWNERS