on-size in frame:size-pref-mixin

Called when the window is resized. The window's new size (in pixels) is provided to the method. The size values are for the entire window, not just the client area.

• (send a-frame:size-pref-mixin on-size width height void
     width : number
     height : number

  Updates the preferences, according to the width and height. The preferences key is the one passed to the initialization argument of the class.