[mutter/gnome-3-28] wayland/xdg-foreign: Fix child surface validation check

[Jonas Ådahl <jadahl src gnome org>]

commit 889c56c776520c1bf430cc13cd87da2ab78d6161
Author: Jonas Ådahl <jadahl gmail com>
Date:   Fri May 4 21:52:45 2018 +0200

    wayland/xdg-foreign: Fix child surface validation check
    
    The role type should be either an xdg-shell toplevel, or a
    xdg-shell unstable v6 toplevel.
    
    Closes: https://gitlab.gnome.org/GNOME/mutter/issues/138
    
    
    (cherry picked from commit 332d55f7f6b5d646ea9bc2586b2135113c9d3074)

 src/wayland/meta-wayland-xdg-foreign.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)
---
diff --git a/src/wayland/meta-wayland-xdg-foreign.c b/src/wayland/meta-wayland-xdg-foreign.c
index cecef50a9..49ada7ada 100644
--- a/src/wayland/meta-wayland-xdg-foreign.c
+++ b/src/wayland/meta-wayland-xdg-foreign.c
@@ -252,10 +252,8 @@ is_valid_child (MetaWaylandSurface *surface)
   if (!surface->role)
     return FALSE;
 
-  if (!META_IS_WAYLAND_XDG_SURFACE (surface->role))
-    return FALSE;
-
-  if (!META_IS_WAYLAND_ZXDG_SURFACE_V6 (surface->role))
+  if (!META_IS_WAYLAND_XDG_TOPLEVEL (surface->role) &&
+      !META_IS_WAYLAND_ZXDG_TOPLEVEL_V6 (surface->role))
     return FALSE;
 
   if (!surface->window)