The RandR extension is obviously tied to X.Org, but similar functionality now exists via a "wlrandr" protocol extension. The "wlrandr" extension allows for switching modes and also ships a weston-switch-mode utility for changing modes just like xrandr. Right now only the DRM back-end is supported by this work. The patch can be found on the mailing list.
However, right now there is some uncertainty whether this will be accepted since previously it's been talked about for not exposing resolution information over the Wayland protocol. For more details on that see this reply.