This can be used in the future to test NV12 video frames with encoders, both
from unittests and from tools like video_loopback.
Tested using video_loopback with generator NV12.
Bug: webrtc:11978
Change-Id: I0d24ae3ebab2267f076703cbda81e99cec465ec8
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/185045
Commit-Queue: Evan Shrubsole <eshr@google.com>
Reviewed-by: Stefan Holmer <stefan@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#32206}