[mutter] clutter/features: Remove 'swap-events' feature

[Marge Bot <marge-bot src gnome org>]

commit 57964becb6214aa1d62df2ee5b9db83281a90eef
Author: Jonas Ådahl <jadahl gmail com>
Date:   Fri Sep 17 09:52:23 2021 +0200

    clutter/features: Remove 'swap-events' feature
    
    We still use swap events, but it's a backend detail, doesn't need to be
    exposed anywhere else.
    
    Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2002>

 clutter/clutter/clutter-backend.c | 6 ------
 clutter/clutter/clutter-enums.h   | 2 --
 2 files changed, 8 deletions(-)
---
diff --git a/clutter/clutter/clutter-backend.c b/clutter/clutter/clutter-backend.c
index 1e41c2af7b..d11cd8682b 100644
--- a/clutter/clutter/clutter-backend.c
+++ b/clutter/clutter/clutter-backend.c
@@ -381,12 +381,6 @@ clutter_backend_real_get_features (ClutterBackend *backend)
       flags |= CLUTTER_FEATURE_STAGE_STATIC;
     }
 
-  if (cogl_clutter_winsys_has_feature (COGL_WINSYS_FEATURE_SWAP_BUFFERS_EVENT))
-    {
-      CLUTTER_NOTE (BACKEND, "Cogl supports swap buffers complete events");
-      flags |= CLUTTER_FEATURE_SWAP_EVENTS;
-    }
-
   return flags;
 }
 
diff --git a/clutter/clutter/clutter-enums.h b/clutter/clutter/clutter-enums.h
index 3bfe3412b9..38f3ee55be 100644
--- a/clutter/clutter/clutter-enums.h
+++ b/clutter/clutter/clutter-enums.h
@@ -901,7 +901,6 @@ typedef enum /*< prefix=CLUTTER_SCROLL >*/
  * @CLUTTER_FEATURE_STAGE_STATIC: Set if stage size if fixed (i.e framebuffer)
  * @CLUTTER_FEATURE_SHADERS_GLSL: Set if the backend supports GLSL shaders.
  * @CLUTTER_FEATURE_STAGE_MULTIPLE: Set if multiple stages are supported.
- * @CLUTTER_FEATURE_SWAP_EVENTS: Set if the GLX_INTEL_swap_event is supported.
  *
  * Runtime flags indicating specific features available via Clutter window
  * system and graphics backend.
@@ -913,7 +912,6 @@ typedef enum
   CLUTTER_FEATURE_STAGE_STATIC           = (1 << 6),
   CLUTTER_FEATURE_SHADERS_GLSL           = (1 << 9),
   CLUTTER_FEATURE_STAGE_MULTIPLE         = (1 << 11),
-  CLUTTER_FEATURE_SWAP_EVENTS            = (1 << 12)
 } ClutterFeatureFlags;
 
 /**