[gtk+] gdk/wayland: Avoid idempotent wl_subsurface.set_position calls

[Carlos Garnacho <carlosg src gnome org>]

commit 1607f8c4c64b95329f0c02fde7070c35b2bfb2ad
Author: Carlos Garnacho <carlosg gnome org>
Date:   Fri Oct 6 01:06:03 2017 +0200

    gdk/wayland: Avoid idempotent wl_subsurface.set_position calls
    
    These may not result on wl_surface.frame callbacks, yet we do trigger
    a frame clock tick that would get stuck on the lack of such callback.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=784314

 gdk/wayland/gdkwindow-wayland.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/gdk/wayland/gdkwindow-wayland.c b/gdk/wayland/gdkwindow-wayland.c
index 1697dcd..cbc7bfb 100644
--- a/gdk/wayland/gdkwindow-wayland.c
+++ b/gdk/wayland/gdkwindow-wayland.c
@@ -2637,7 +2637,8 @@ gdk_window_wayland_move_resize (GdkWindow *window,
   if (with_move)
     {
       /* Each toplevel has in its own "root" coordinate system */
-      if (GDK_WINDOW_TYPE (window) != GDK_WINDOW_TOPLEVEL)
+      if (GDK_WINDOW_TYPE (window) != GDK_WINDOW_TOPLEVEL &&
+          (window->x != x || window->y != y))
         {
           window->x = x;
           window->y = y;