Add Video API unit tests, fix auto speakerphone logic.

- Move some of the single call Telecom system tests to a new BasicCallTests
class.
- Change visibility of some methods in TelecomSystemTest to faciliate the
creation of other system test classes.
- Added VideoProviderTest which exercises the Video APIs.
- Created Mock Video Provider.

Change-Id: Id314c18b77e8c635fbde0232a1ccfae851a3071c