[gtk] print portal: don't leak window handles

[Matthias Clasen <matthiasc src gnome org>]

commit 79b87cc543ec0b6206fbe0b733cfe4db06858f06
Author: Matthias Clasen <mclasen redhat com>
Date:   Wed Aug 15 23:21:15 2018 +0000

    print portal: don't leak window handles
    
    Pointed out by Christian Persch.
    
    Closes https://gitlab.gnome.org/GNOME/gtk/issues/1274

 gtk/gtkprintoperation-portal.c | 2 ++
 1 file changed, 2 insertions(+)
---
diff --git a/gtk/gtkprintoperation-portal.c b/gtk/gtkprintoperation-portal.c
index a6683fd212..ded550262b 100644
--- a/gtk/gtkprintoperation-portal.c
+++ b/gtk/gtkprintoperation-portal.c
@@ -62,6 +62,8 @@ portal_data_free (gpointer data)
 {
   PortalData *portal = data;
 
+  if (portal->parent)
+    gtk_window_unexport_handle (portal->parent);
   g_object_unref (portal->op);
   g_object_unref (portal->proxy);
   if (portal->loop)