Addresses a long-standing TODO. Now, when calling IpClient's
startProvisioning(), the interface has to be available (i.e.
InterfaceParams#getByName() must return non-null).
Also:
- add a test
- refactor for testability
- delete some constructors no longer used
- properly handle passed-in null IpClient.Callback
- some more IpManager -> IpClient renaming
- permit recording metrics before starting a provisioning
attempt (logging immediate errors) without Log.wtf().
Test: as follows
- built
- flashed
- booted
- runtest frameworks/opt/net/wifi/tests/wifitests/runtests.sh passes
- runtest frameworks-net passes
- basic WiFi IpClient connections works fine
Bug: 62476366
Bug: 73487570
Change-Id: Ic83ad2a65637277dcb273feb27b2d1bb7a11eb2b
b152cd0aa4