MediaTrackConstraints - Web APIs
resizemode a constraindomstring object specifying a mode or an array of modes the ua can use to derive the resolution of a video track.

MediaTrackSettings - Web APIs
resizemode a domstring indicating the current value of the resizemode property, specifying the mode used by the user agent to derive the resolution of the track.

MediaTrackSupportedConstraints - Web APIs
resizemode a boolean value whose value is true if the resizemode constraint is supported in the current environment.