Updates to TestconnectionService.

1. Added test pattern video -- useful for testing animation of the
display surface.
2. Retrieve camera video dimensions.
3. Implemented camera setup flow which InCall UI expected (i.e.
set camera, communicate capabilities, set surface).

Bug: 16043064
Change-Id: Ia69fc091dcbb5fa2e207b56dce21e01e671a8a3e