[mutter] display: Don't call x11 backend code when running native

[Adel Gadllah <agadllah src gnome org>]

commit 4e584c2cf00b97a2c9da8786c9211ed0563d3586
Author: Adel Gadllah <adel gadllah gmail com>
Date:   Sun Apr 27 20:22:47 2014 +0200

    display: Don't call x11 backend code when running native
    
    https://bugzilla.gnome.org/show_bug.cgi?id=729044

 src/core/display.c |   12 ++++++++++++
 1 files changed, 12 insertions(+), 0 deletions(-)
---
diff --git a/src/core/display.c b/src/core/display.c
index d087940..718540b 100644
--- a/src/core/display.c
+++ b/src/core/display.c
@@ -2128,6 +2128,12 @@ void
 meta_display_grab_focus_window_button (MetaDisplay *display,
                                        MetaWindow  *window)
 {
+  MetaBackend *backend = meta_get_backend ();
+
+  /* Do nothing under non-X11 backends */
+  if (!META_IS_BACKEND_X11 (backend))
+    return;
+
   /* Grab button 1 for activating unfocused windows */
   meta_verbose ("Grabbing unfocused window buttons for %s\n", window->desc);
 
@@ -2177,6 +2183,12 @@ void
 meta_display_ungrab_focus_window_button (MetaDisplay *display,
                                          MetaWindow  *window)
 {
+  MetaBackend *backend = meta_get_backend ();
+
+  /* Do nothing under non-X11 backends */
+  if (!META_IS_BACKEND_X11 (backend))
+    return;
+
   meta_verbose ("Ungrabbing unfocused window buttons for %s\n", window->desc);
 
   if (!window->have_focus_click_grab)