Google chrome DOMException: Permission denied by system for navigator.mediaDevices.getUserMedia
Since MacOS Mojave, camera and microphone require OS permissions.
This applies to all non-Apple products, including all browsers other than Safari.
Check System Preferences > Security & Privacy > Privacy > Camera & Microphone. Make sure Chrome is listed and has a checkbox.
You should have gotten a special OS prompt about this the first time Chrome tried to access them. But if it accidentally got blocked somehow, you won't ever be prompted again.