Code review comment for lp:~mir-team/mir/allow-lock-surf-orientation

> +1 for mir_surface_{get,set}_supported_orientations.
>
> Nit:
> 178 +MirPermittedOrientations
> mir_surface_get_permitted_orientations(MirSurface *surf)
> ...
> 184 + if (surf)
> 185 + {
>
> Incorrect precondition check. If you're going to do a precondition check it
> should be mir_surface_is_valid(surf), and it should abort() if the
> precondition fails.

OK, I guess we ought to fix all the other function preconditions checks as well as this was copy/pasta.