[gtk+] dnd: Avoid a crash

[Matthias Clasen <matthiasc src gnome org>]

commit e9300e2f7917dd67c8adc8c08390c44ca22f0d9b
Author: Matthias Clasen <mclasen redhat com>
Date:   Sat Feb 20 22:43:43 2016 -0500

    dnd: Avoid a crash
    
    gtk_image_definition_new_icon_name ("") returns NULL. Bail
    out early in this case to avoid unreffing NULL later.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=762392

 gtk/gtkdnd.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/gtk/gtkdnd.c b/gtk/gtkdnd.c
index e00aab2..48be48c 100644
--- a/gtk/gtkdnd.c
+++ b/gtk/gtkdnd.c
@@ -2857,7 +2857,7 @@ gtk_drag_set_icon_name (GdkDragContext *context,
   GtkImageDefinition *def;
 
   g_return_if_fail (GDK_IS_DRAG_CONTEXT (context));
-  g_return_if_fail (icon_name != NULL);
+  g_return_if_fail (icon_name != NULL && icon_name[0] != '\0');
 
   def = gtk_image_definition_new_icon_name (icon_name);
   set_icon_helper (context, def, hot_x, hot_y);