[gtk/wip/matthiasc/popup4: 113/115] Revert "wayland: Remove a mistaken check"

[Matthias Clasen <matthiasc src gnome org>]

commit 6429cc88315ce7601c1584ecbfdfaddc6f6e8581
Author: Jonas Ådahl <jadahl gmail com>
Date:   Wed Apr 24 13:28:10 2019 +0200

    Revert "wayland: Remove a mistaken check"
    
    This reverts commit e07206d1e0b9d5b26445954bfdf77e537cb27b1f.

 gdk/wayland/gdksurface-wayland.c | 8 ++++++++
 1 file changed, 8 insertions(+)
---
diff --git a/gdk/wayland/gdksurface-wayland.c b/gdk/wayland/gdksurface-wayland.c
index 69730277e1..bf553670c1 100644
--- a/gdk/wayland/gdksurface-wayland.c
+++ b/gdk/wayland/gdksurface-wayland.c
@@ -2155,6 +2155,14 @@ gdk_wayland_surface_create_xdg_popup (GdkSurface     *surface,
       g_warning ("Can't map popup, already mapped");
       return;
     }
+  if ((display->current_popups &&
+       g_list_last (display->current_popups)->data != parent) ||
+      (!display->current_popups &&
+       !is_realized_toplevel (parent)))
+    {
+      g_warning ("Tried to map a popup with a non-top most parent");
+      return;
+    }
 
   gdk_surface_freeze_updates (surface);