The Chrome update detector mechanism also does another "fun" thing: it prevents use of your camera (and probably mic too) if it sees an update is available. But, obviously, it doesn't tell you that this is why your camera isn't working.

So, if you are trying to join an interview or exam and your camera and/or mic aren't working, check if you happen to have a small orange excalamtion point somewhere in your Chrome UI, chances are that's the reason.