io/system: remove resize actions

Allowing clients to initiate resize gestures is a waste: macOS
doesn't support them, and the only reason we added them was to
implement client-side decorations for Wayland. Now all desktop
platforms implement resize gestures as needed, and we no longer
need the system.Action actions.

Signed-off-by: Elias Naur <mail@eliasnaur.com>

widget/material/decorations.go

@@ -45,9 +45,6 @@ func (d DecorationsStyle) Layout(gtx layout.Context) layout.Dimensions {
 	r := clip.Rect{Max: dims.Size}
 	paint.FillShape(gtx.Ops, d.Background, r.Op())
 	decos.Add(gtx.Ops)
-	if !d.Decorations.Maximized() {
-		d.Decorations.LayoutResize(gtx, d.Actions)
-	}
 	return dims
 }