Add option to skip and avoid captive portals.

Test: ConnectivityServiceTest updated with test cases.
Test: Manually tested against att-wifi in B42.
Bug: 30222699
Change-Id: Ibe63942da04748ab0406e24e0f44be31d47710a0
(cherry picked from commit 3fd101e574f3ae92987a6cf2d72b7e41b20c476b)
2 files changed
tree: 2151ad4dcf9ddf0f56ff297d079c1167aaa86c58
  1. core/
  2. services/
  3. tests/