[gimp] app: add precondition checks to gimp_gegl_convert_color_profile()

[Michael Natterer <mitch src gnome org>]

commit 6798f7d4cdb90d1461fc5343bc6ea7c8e4cd9dee
Author: Michael Natterer <mitch gimp org>
Date:   Wed Aug 8 23:04:08 2018 +0200

    app: add precondition checks to gimp_gegl_convert_color_profile()

 app/gegl/gimp-gegl-loops.cc | 6 ++++++
 1 file changed, 6 insertions(+)
---
diff --git a/app/gegl/gimp-gegl-loops.cc b/app/gegl/gimp-gegl-loops.cc
index 6e7929c9d2..f123edc7a0 100644
--- a/app/gegl/gimp-gegl-loops.cc
+++ b/app/gegl/gimp-gegl-loops.cc
@@ -955,6 +955,12 @@ gimp_gegl_convert_color_profile (GeglBuffer               *src_buffer,
   const Babl         *src_format;
   const Babl         *dest_format;
 
+  g_return_if_fail (GEGL_IS_BUFFER (src_buffer));
+  g_return_if_fail (GIMP_IS_COLOR_PROFILE (src_profile));
+  g_return_if_fail (GEGL_IS_BUFFER (dest_buffer));
+  g_return_if_fail (GIMP_IS_COLOR_PROFILE (dest_profile));
+  g_return_if_fail (progress == NULL || GIMP_IS_PROGRESS (progress));
+
   src_format  = gegl_buffer_get_format (src_buffer);
   dest_format = gegl_buffer_get_format (dest_buffer);