This should open a local camera feed.
If it does not, there may be a permission problem.
This should create a WebRTC P2P connection and open a remote camera feed.
The remote camera feed on the right will have a slight lag.
The delay is caused by the video stream being encrypted, sent over and being decrypted again.
Audio is muted to prevent feedback noises.
If you see two camera feeds, everything is OK.
If you do NOT see a second camera feed, your System WebView is broken.
More info.