[gtk+] box: Use an element name

[Matthias Clasen <matthiasc src gnome org>]

commit 95df0fb6f5ad8fb24a0c99e593c17a20782ef307
Author: Matthias Clasen <mclasen redhat com>
Date:   Thu Nov 19 07:07:26 2015 -0500

    box: Use an element name

 gtk/gtkbox.c |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)
---
diff --git a/gtk/gtkbox.c b/gtk/gtkbox.c
index ab0ce03..945f928 100644
--- a/gtk/gtkbox.c
+++ b/gtk/gtkbox.c
@@ -71,6 +71,10 @@
  *
  * Note that a single-row or single-column #GtkGrid provides exactly
  * the same functionality as #GtkBox.
+ *
+ * # CSS names
+ *
+ * GtkBox uses a single CSS node with name box.
  */
 
 #include "config.h"
@@ -343,6 +347,7 @@ gtk_box_class_init (GtkBoxClass *class)
   gtk_container_class_install_child_properties (container_class, LAST_CHILD_PROP, child_props);
 
   gtk_widget_class_set_accessible_role (widget_class, ATK_ROLE_FILLER);
+  gtk_widget_class_set_css_name (widget_class, "box");
 }
 
 static void