[gtk+] file chooser button: Set a CSS name

[Matthias Clasen <matthiasc src gnome org>]

commit 07e6eae3e59c9c0eba9fde23492b566b9c474840
Author: Matthias Clasen <mclasen redhat com>
Date:   Fri Mar 11 18:30:36 2016 -0500

    file chooser button: Set a CSS name
    
    This lets us differentiate the main node from regular boxes.

 gtk/gtkfilechooserbutton.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
---
diff --git a/gtk/gtkfilechooserbutton.c b/gtk/gtkfilechooserbutton.c
index e9e8147..5178b77 100644
--- a/gtk/gtkfilechooserbutton.c
+++ b/gtk/gtkfilechooserbutton.c
@@ -471,6 +471,8 @@ gtk_file_chooser_button_class_init (GtkFileChooserButtonClass * class)
   gtk_widget_class_bind_template_callback (widget_class, button_clicked_cb);
   gtk_widget_class_bind_template_callback (widget_class, combo_box_changed_cb);
   gtk_widget_class_bind_template_callback (widget_class, combo_box_notify_popup_shown_cb);
+
+  gtk_widget_class_set_css_name (widget_class, "filechooserbutton");
 }
 
 static void