[gdk-pixbuf] Plug a memory leak when using GBytes

[Emmanuele Bassi <ebassi src gnome org>]

commit a17ef43a3c25e09d33a686ba3575667eaf084760
Author: Vitaly Kirsanov <krokoziabla gmail com>
Date:   Wed Sep 13 13:07:00 2017 +0000

    Plug a memory leak when using GBytes
    
    Calling g_bytes_unref_to_data() will copy the contents of the bytes
    buffer, so we need to free the data.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=787626

 gdk-pixbuf/gdk-pixbuf.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
---
diff --git a/gdk-pixbuf/gdk-pixbuf.c b/gdk-pixbuf/gdk-pixbuf.c
index a0454c3..c86d096 100644
--- a/gdk-pixbuf/gdk-pixbuf.c
+++ b/gdk-pixbuf/gdk-pixbuf.c
@@ -715,6 +715,8 @@ gdk_pixbuf_get_pixels_with_length (const GdkPixbuf *pixbuf,
                 gsize len;
                 mut_pixbuf->pixels = g_bytes_unref_to_data (pixbuf->bytes, &len);
                 mut_pixbuf->bytes = NULL;
+                mut_pixbuf->destroy_fn = free_buffer;
+                mut_pixbuf->destroy_fn_data = NULL;
         }
 
         if (length)