cullable: Check if effects are disabled

Currently we skip culling actors if they have any effects set. But
effects can be disabled, in which case we don't need to do that.

https://gitlab.gnome.org/GNOME/mutter/merge_requests/1052

src/compositor/meta-cullable.c

@@ -28,6 +28,22 @@
 
 G_DEFINE_INTERFACE (MetaCullable, meta_cullable, CLUTTER_TYPE_ACTOR);
 
+static gboolean
+has_active_effects (ClutterActor *actor)
+{
+  g_autoptr (GList) effects = NULL;
+  GList *l;
+
+  effects = clutter_actor_get_effects (actor);
+  for (l = effects; l != NULL; l = l->next)
+    {
+      if (clutter_actor_meta_get_enabled (CLUTTER_ACTOR_META (l->data)))
+        return TRUE;
+    }
+
+  return FALSE;
+}
+
 /**
  * SECTION:meta-cullable
  * @title: MetaCullable
@@ -97,7 +113,7 @@ meta_cullable_cull_out_children (MetaCullable   *cullable,
        * as well for the same reason, but omitted for simplicity in the
        * hopes that no-one will do that.
        */
-      if (needs_culling && clutter_actor_has_effects (child))
+      if (needs_culling && has_active_effects (child))
         needs_culling = FALSE;
 
       if (needs_culling && !meta_cullable_is_untransformed (META_CULLABLE (child)))