[totem] icon-helpers: Add guard in totem_grilo_get_icon()

[Bastien Nocera <hadess src gnome org>]

commit 5a789a8780d61b08ea011271c9b9fa61d36030cb
Author: Bastien Nocera <hadess hadess net>
Date:   Fri Mar 6 17:09:07 2015 +0100

    icon-helpers: Add guard in totem_grilo_get_icon()
    
    To avoid crashing when we use the API badly.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=743247

 src/icon-helpers.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
---
diff --git a/src/icon-helpers.c b/src/icon-helpers.c
index 9c91afc..db50752 100644
--- a/src/icon-helpers.c
+++ b/src/icon-helpers.c
@@ -451,6 +451,8 @@ GdkPixbuf *
 totem_grilo_get_icon (GrlMedia *media,
                      gboolean *thumbnailing)
 {
+       g_return_val_if_fail (thumbnailing != NULL, NULL);
+
        *thumbnailing = FALSE;
 
        if (GRL_IS_MEDIA_BOX (media)) {