[gtk+] dialog: Use an element name

[Matthias Clasen <matthiasc src gnome org>]

commit 3e8eacc8b7719b679b5372d77d36c0e429368762
Author: Matthias Clasen <mclasen redhat com>
Date:   Tue Nov 24 07:41:26 2015 -0500

    dialog: Use an element name
    
    This will help differentiating dialogs from other windows, style-wise.

 gtk/gtkdialog.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
---
diff --git a/gtk/gtkdialog.c b/gtk/gtkdialog.c
index a0601f9..e2713b2 100644
--- a/gtk/gtkdialog.c
+++ b/gtk/gtkdialog.c
@@ -665,6 +665,8 @@ gtk_dialog_class_init (GtkDialogClass *class)
   gtk_widget_class_bind_template_child_internal_private (widget_class, GtkDialog, action_area);
   gtk_widget_class_bind_template_child_internal_private (widget_class, GtkDialog, action_box);
   gtk_widget_class_bind_template_callback (widget_class, gtk_dialog_delete_event_handler);
+
+  gtk_widget_class_set_css_name (widget_class, "dialog");
 }
 
 static void