Implement new video-call-related buttons.

- Implemented downgrade/upgrade, switch camera, pause camear.
- Implemented code to find front/back-facing cameraIds.
- Also, cleaned up listener logic in CallButtonFragment to be
more consistent.

Bug: 16014280
Change-Id: I267a73943dc768900b663bb4db6ec52f4a35cac5
3 files changed
tree: 191ac62f84fdf5bde2f96597b707926ef2efc1e9
  1. InCallUI/