Merge "Add callback registration in ConnectivityService." am: 29edc0ecc9 am: 89a5e805f9 am: 7d4ebb11d6

Change-Id: I596d4788f6d35f1adf110d8edd390f5632b4dc06
tree: a7e7e66c656e3af1d4a921a5c24a0135536f32c5
  1. core/
  2. services/
  3. tests/