[gtk+] window: Clear the renderer un unrealize

[Benjamin Otte <otte src gnome org>]

commit 8059f9bb3a8a4991a364db797965efffee2dba1d
Author: Benjamin Otte <otte redhat com>
Date:   Wed Nov 1 15:46:20 2017 +0100

    window: Clear the renderer un unrealize
    
    We disconnect from the GDK window, so the renderer can't keep any useful
    state.
    
    Plus, we might be using an entirely different window next time we
    realize (after a call to gtk_window_set_display() for example) that should
    use a completely different renderer anyway.

 gtk/gtkwindow.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/gtk/gtkwindow.c b/gtk/gtkwindow.c
index c06b59d..c9716a6 100644
--- a/gtk/gtkwindow.c
+++ b/gtk/gtkwindow.c
@@ -6995,8 +6995,8 @@ gtk_window_unrealize (GtkWidget *widget)
                         (GtkCallback) gtk_widget_unrealize,
                         NULL);
 
-  if (priv->renderer != NULL)
-    gsk_renderer_unrealize (priv->renderer);
+  gsk_renderer_unrealize (priv->renderer);
+  g_clear_object (&priv->renderer);
 
   GTK_WIDGET_CLASS (gtk_window_parent_class)->unrealize (widget);