[gtk/fix-scrollbar-sizing] gizmo: Chain up in css_changed

[Matthias Clasen <matthiasc src gnome org>]

commit bb0a1b0cfe74d74c97ba2711d1827843d21a2c81
Author: Matthias Clasen <mclasen redhat com>
Date:   Mon Feb 15 14:26:52 2021 -0500

    gizmo: Chain up in css_changed
    
    css_changed is a vfunc that *must* chain up.
    Failure to do so broke the resizing of overlay scrollbars,
    amongst other things.
    
    This bug was introduced in 39f72b38341d2ff2d67.

 gtk/gtkgizmo.c | 2 ++
 1 file changed, 2 insertions(+)
---
diff --git a/gtk/gtkgizmo.c b/gtk/gtkgizmo.c
index 45b23b20eb..d1af37aa65 100644
--- a/gtk/gtkgizmo.c
+++ b/gtk/gtkgizmo.c
@@ -88,6 +88,8 @@ gtk_gizmo_css_changed (GtkWidget         *widget,
 {
   GtkGizmo *self = GTK_GIZMO (widget);
 
+  GTK_WIDGET_CLASS (gtk_gizmo_parent_class)->css_changed (widget, change);
+
   if (self->css_changed_func)
     self->css_changed_func (self, change);
 }