[mutter] frame: Only XSync when we're on the X11 compositor backend

[Jasper St. Pierre <jstpierre src gnome org>]

commit 1749a85e96855240652cef423e90879b05118040
Author: Jasper St. Pierre <jstpierre mecheye net>
Date:   Thu Jul 10 13:29:20 2014 -0400

    frame: Only XSync when we're on the X11 compositor backend
    
    The only case we have is the case where the two X11 connections are the
    same. When on Wayland, the XSync is costly and expensive, and we should
    minimize it.

 src/core/frame.c |   15 +++++++++++----
 1 files changed, 11 insertions(+), 4 deletions(-)
---
diff --git a/src/core/frame.c b/src/core/frame.c
index 8901aad..13cbbd2 100644
--- a/src/core/frame.c
+++ b/src/core/frame.c
@@ -26,6 +26,7 @@
 #include "bell.h"
 #include <meta/errors.h>
 #include "keybindings-private.h"
+#include "backends/x11/meta-backend-x11.h"
 
 #define EVENT_MASK (SubstructureRedirectMask |                     \
                     StructureNotifyMask | SubstructureNotifyMask | \
@@ -159,10 +160,16 @@ meta_window_ensure_frame (MetaWindow *window)
 
   meta_ui_map_frame (frame->window->screen->ui, frame->xwindow);
 
-  /* Since the backend takes keygrabs on another connection, make sure
-   * to sync the GTK+ connection to ensure that the frame window has
-   * been created on the server at this point. */
-  XSync (window->display->xdisplay, False);
+  {
+    MetaBackend *backend = meta_get_backend ();
+    if (META_IS_BACKEND_X11 (backend))
+      {
+        /* Since the backend takes keygrabs on another connection, make sure
+         * to sync the GTK+ connection to ensure that the frame window has
+         * been created on the server at this point. */
+        XSync (window->display->xdisplay, False);
+      }
+  }
 
   /* Move keybindings to frame instead of window */
   meta_window_grab_keys (window);