[grilo] GrlPlsFilterFunc: Document how the refcounting works

[Xavier Claessens <xclaesse src gnome org>]

commit 0a33601db466b167a8d732e00b172eeea53a5f9e
Author: Xavier Claessens <xavier claessens collabora com>
Date:   Wed Apr 23 15:34:29 2014 -0400

    GrlPlsFilterFunc: Document how the refcounting works
    
    https://bugzilla.gnome.org/show_bug.cgi?id=728812

 libs/pls/grl-pls.h |    7 +++++--
 1 files changed, 5 insertions(+), 2 deletions(-)
---
diff --git a/libs/pls/grl-pls.h b/libs/pls/grl-pls.h
index 6809d1b..659d90e 100644
--- a/libs/pls/grl-pls.h
+++ b/libs/pls/grl-pls.h
@@ -31,14 +31,17 @@ G_BEGIN_DECLS
 /**
  * GrlPlsFilterFunc:
  * @source: the #GrlSource the browse call came from
- * @media: a #GrlMedia to operate on
+ * @media: (transfer full): a #GrlMedia to operate on
  * @user_data: user data passed to the browse call
  *
  * Callback type to filter, or modify #GrlMedia created
  * when parsing a playlist using one of grl_pls_browse(),
  * grl_pls_browse_sync() or grl_pls_browse_by_spec().
  *
- * Returns: %NULL to not add this entry to the results,
+ * The callback is responsible for unreffing @media when returning %NULL or
+ * another #GrlMedia.
+ *
+ * Returns: (transfer full): %NULL to not add this entry to the results,
  *   or a new #GrlMedia populated with metadata of your choice.
  */
 typedef GrlMedia * (*GrlPlsFilterFunc) (GrlSource *source,