[gtk] gridview: Make constructor arguments nullable

[Matthias Clasen <matthiasc src gnome org>]

commit 887539e4ff629686cd94a6b144a3a53a3bc40b1d
Author: Matthias Clasen <mclasen redhat com>
Date:   Thu Sep 3 14:18:41 2020 -0400

    gridview: Make constructor arguments nullable
    
    I forgot to adjust the precondition when copying things
    around.

 gtk/gtkgridview.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/gtk/gtkgridview.c b/gtk/gtkgridview.c
index 5e3af58f5b..f20c34ba84 100644
--- a/gtk/gtkgridview.c
+++ b/gtk/gtkgridview.c
@@ -1200,7 +1200,7 @@ gtk_grid_view_new (GtkSelectionModel  *model,
   GtkWidget *result;
 
   g_return_val_if_fail (model == NULL || GTK_IS_SELECTION_MODEL (model), NULL);
-  g_return_val_if_fail (GTK_IS_LIST_ITEM_FACTORY (factory), NULL);
+  g_return_val_if_fail (factory == NULL || GTK_IS_LIST_ITEM_FACTORY (factory), NULL);
 
   result = g_object_new (GTK_TYPE_GRID_VIEW,
                          "model", model,