[mutter/gbsneto/expose-framebuffer-for-introspection: 5/6] cogl/framebuffer: Mark CoglOffscreen as a CoglFramebuffer implementation

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

commit 546812ab27537b7c9b83e13a54781346a7fa0a73
Author: Georges Basile Stavracas Neto <georges stavracas gmail com>
Date:   Tue Oct 9 19:43:35 2018 -0300

    cogl/framebuffer: Mark CoglOffscreen as a CoglFramebuffer implementation
    
    CoglOffscreen is effectively a CoglFramebuffer, but it isn't being marked as
    such by the GType machinery. This makes it impossible for introspection to
    correctly set this class up.
    
    Fix that by adding a COGL_GTYPE_IMPLEMENT_INTERFACE() code into the declaration
    of CoglOffscreen. This does not have any functional changes though.

 cogl/cogl/cogl-framebuffer.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
---
diff --git a/cogl/cogl/cogl-framebuffer.c b/cogl/cogl/cogl-framebuffer.c
index 73faae670..f2df9c229 100644
--- a/cogl/cogl/cogl-framebuffer.c
+++ b/cogl/cogl/cogl-framebuffer.c
@@ -66,7 +66,8 @@ static void _cogl_offscreen_free (CoglOffscreen *offscreen);
 COGL_OBJECT_DEFINE_WITH_CODE_GTYPE (Offscreen, offscreen,
                                     _cogl_offscreen_class.virt_unref =
                                     _cogl_framebuffer_unref);
-COGL_GTYPE_DEFINE_CLASS (Offscreen, offscreen);
+COGL_GTYPE_DEFINE_CLASS (Offscreen, offscreen,
+                         COGL_GTYPE_IMPLEMENT_INTERFACE (framebuffer));
 COGL_OBJECT_DEFINE_DEPRECATED_REF_COUNTING (offscreen);
 COGL_GTYPE_DEFINE_INTERFACE (Framebuffer, framebuffer);