[mutter] clutter/root-node: Require non-null framebuffer on construction

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

commit 61026d181b693d4ae3fcbb2f7dea343452402877
Author: Jonas Ådahl <jadahl gmail com>
Date:   Fri Nov 22 10:12:58 2019 +0100

    clutter/root-node: Require non-null framebuffer on construction
    
    It's the only way it's used, and it removes a usage of deprecated Cogl
    implicit stack API.
    
    https://gitlab.gnome.org/GNOME/mutter/merge_requests/935

 clutter/clutter/clutter-paint-nodes.c | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)
---
diff --git a/clutter/clutter/clutter-paint-nodes.c b/clutter/clutter/clutter-paint-nodes.c
index a0692e6b6..51ebf0739 100644
--- a/clutter/clutter/clutter-paint-nodes.c
+++ b/clutter/clutter/clutter-paint-nodes.c
@@ -165,6 +165,8 @@ clutter_root_node_new (CoglFramebuffer    *framebuffer,
 {
   ClutterRootNode *res;
 
+  g_return_val_if_fail (framebuffer, NULL);
+
   res = _clutter_paint_node_create (CLUTTER_TYPE_ROOT_NODE);
 
   cogl_color_init_from_4ub (&res->clear_color,
@@ -174,11 +176,7 @@ clutter_root_node_new (CoglFramebuffer    *framebuffer,
                             clear_color->alpha);
   cogl_color_premultiply (&res->clear_color);
 
-  if (G_LIKELY (framebuffer != NULL))
-    res->framebuffer = cogl_object_ref (framebuffer);
-  else
-    res->framebuffer = cogl_object_ref (cogl_get_draw_framebuffer ());
-
+  res->framebuffer = cogl_object_ref (framebuffer);
   res->clear_flags = clear_flags;
 
   return (ClutterPaintNode *) res;