ConnectivityManager: improve argument validation

Using Preconditions and dedicated static methods for checking arguments
to improve error stack traces without error messages.

Test: covered by previously added unit test
Bug: 36701874
Change-Id: Id872b2c887a4bca43a8c3644622add1c2ee57c6d
1 file changed
tree: 6fea84ae6ca450128903c94f7a7143b361fa8188
  1. core/
  2. services/
  3. tests/