Adds getCameraFacing() API for CCA

This CL adds getCameraFacing() API for CCA to get camera facing.

Bug: None
Test: Manually
Change-Id: Ic400ed3012416f6d22f61fb553f9a74e7a1c24dd
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1624425
Reviewed-by: Robert Sesek <rsesek@chromium.org>
Reviewed-by: Sheng-hao Tsao <shenghao@chromium.org>
Reviewed-by: Ricky Liang <jcliang@chromium.org>
Commit-Queue: Wei Lee <wtlee@chromium.org>
Cr-Commit-Position: refs/heads/master@{#663003}
12 files changed