[cogl] pixel-buffer: add missing transfer annotation

[Robert Bragg <rbragg src gnome org>]

commit 9c37ace84f54a330625ca2ffefcc8c6e9006caf6
Author: Lionel Landwerlin <llandwerlin gmail com>
Date:   Tue Sep 3 16:16:20 2013 +0100

    pixel-buffer: add missing transfer annotation
    
    Reviewed-by: Robert Bragg <robert linux intel com>
    
    (cherry picked from commit c1597a3364996a17669b83dae40984840b26af04)

 cogl/cogl-pixel-buffer.h |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
---
diff --git a/cogl/cogl-pixel-buffer.h b/cogl/cogl-pixel-buffer.h
index 9c32d06..bde8ddd 100644
--- a/cogl/cogl-pixel-buffer.h
+++ b/cogl/cogl-pixel-buffer.h
@@ -58,6 +58,8 @@ COGL_BEGIN_DECLS
  * If @data isn't %NULL then @size bytes will be read from @data and
  * immediately copied into the new buffer.
  *
+ * Return value: (transfer full): a newly allocated #CoglPixelBuffer
+ *
  * Since: 1.10
  * Stability: unstable
  */