You can clone with
right now uses moz prefix and needs to be enabled via about:config.
For reference, the flag in FF about:config is media.peerconnection.enabled
Also, some things to be aware of, in addition to prefixing getUserMedia:
UPDATE: video.videoWidth and video.videoHeight properties do exist but only have a non-zero value once the "playing" event (and not the "play" event) has fired.
Closing, if everyone's happy with the merged edits.
Awesome, thanks @tagawa !