[gtk+] csswidgetnode: Fix container condition for GtkInvisible

[Timm Bäder <baedert src gnome org>]

commit 6eb3d98de0ef186f56fdec12772b83f319546cba
Author: Timm Bäder <mail baedert org>
Date:   Tue Oct 25 16:52:27 2016 +0200

    csswidgetnode: Fix container condition for GtkInvisible
    
    ... which is a toplevel, but not a container.

 gtk/gtkcsswidgetnode.c |    6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)
---
diff --git a/gtk/gtkcsswidgetnode.c b/gtk/gtkcsswidgetnode.c
index 3983e83..4e63c3f 100644
--- a/gtk/gtkcsswidgetnode.c
+++ b/gtk/gtkcsswidgetnode.c
@@ -94,7 +94,8 @@ gtk_css_widget_node_queue_validate (GtkCssNode *node)
 {
   GtkCssWidgetNode *widget_node = GTK_CSS_WIDGET_NODE (node);
 
-  if (widget_node->widget && _gtk_widget_is_toplevel (widget_node->widget))
+  if (widget_node->widget && _gtk_widget_is_toplevel (widget_node->widget) &&
+      GTK_IS_CONTAINER (widget_node->widget))
     widget_node->validate_cb_id = gtk_widget_add_tick_callback (widget_node->widget,
                                                                 gtk_css_widget_node_queue_callback,
                                                                 node,
@@ -106,7 +107,8 @@ gtk_css_widget_node_dequeue_validate (GtkCssNode *node)
 {
   GtkCssWidgetNode *widget_node = GTK_CSS_WIDGET_NODE (node);
 
-  if (widget_node->widget && _gtk_widget_is_toplevel (widget_node->widget))
+  if (widget_node->widget && _gtk_widget_is_toplevel (widget_node->widget) &&
+      GTK_IS_CONTAINER (widget_node->widget))
     gtk_widget_remove_tick_callback (widget_node->widget,
                                      widget_node->validate_cb_id);
 }