[mutter] renderer/x11: Enable GPU memory purge error extension if available

[Jonas Ådahl <jadahl src gnome org>]

commit 86ab3878e7b62b74c61b95506042eb438202b23a
Author: Jonas Ådahl <jadahl gmail com>
Date:   Fri Feb 2 14:34:50 2018 +0800

    renderer/x11: Enable GPU memory purge error extension if available
    
    This was done by the clutter X11 backend before prior to introducing
    MetaRenderer, but during that work, enabling of said extension was lost.
    Let's turn it on again.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=739178

 src/backends/x11/meta-backend-x11.c  | 2 --
 src/backends/x11/meta-renderer-x11.c | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)
---
diff --git a/src/backends/x11/meta-backend-x11.c b/src/backends/x11/meta-backend-x11.c
index f447f785f..acb2b1d90 100644
--- a/src/backends/x11/meta-backend-x11.c
+++ b/src/backends/x11/meta-backend-x11.c
@@ -705,8 +705,6 @@ meta_backend_x11_init (MetaBackendX11 *x11)
    */
   XInitThreads();
 
-  clutter_x11_request_reset_on_video_memory_purge ();
-
   /* We do X11 event retrieval ourselves */
   clutter_x11_disable_event_retrieval ();
 }
diff --git a/src/backends/x11/meta-renderer-x11.c b/src/backends/x11/meta-renderer-x11.c
index 2e2958b09..bb52d3caf 100644
--- a/src/backends/x11/meta-renderer-x11.c
+++ b/src/backends/x11/meta-renderer-x11.c
@@ -74,6 +74,7 @@ meta_renderer_x11_create_cogl_renderer (MetaRenderer *renderer)
   cogl_renderer_set_custom_winsys (cogl_renderer, get_x11_cogl_winsys_vtable,
                                    NULL);
   cogl_xlib_renderer_set_foreign_display (cogl_renderer, xdisplay);
+  cogl_xlib_renderer_request_reset_on_video_memory_purge (cogl_renderer, TRUE);
 
   /* Set up things so that if the INTEL_swap_event extension is not present,
    * but the driver is known to have good thread support, we use an extra