[gtk+] wayland: Set a null cursor surface when cursor buffer is null

[Matthias Clasen <matthiasc src gnome org>]

commit dc65abc44c403e980b0f74815d63d979d8f663d9
Author: Jonas Ådahl <jadahl gmail com>
Date:   Fri Nov 20 16:49:12 2015 +0800

    wayland: Set a null cursor surface when cursor buffer is null
    
    If the buffer of a cursor is NULL, for example if its an empty cursor,
    just set the cursor surface to NULL as well. Not doing this we'll use
    uninitialized hotspot coordinates, dimensions and scales.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=758025

 gdk/wayland/gdkdevice-wayland.c |   19 +++++++++++++++----
 1 files changed, 15 insertions(+), 4 deletions(-)
---
diff --git a/gdk/wayland/gdkdevice-wayland.c b/gdk/wayland/gdkdevice-wayland.c
index 74aba25..2f86ee1 100644
--- a/gdk/wayland/gdkdevice-wayland.c
+++ b/gdk/wayland/gdkdevice-wayland.c
@@ -225,16 +225,27 @@ gdk_wayland_device_update_window_cursor (GdkWaylandDeviceData *wd)
   if (!wd->wl_pointer)
     return retval;
 
-  wl_pointer_set_cursor (wd->wl_pointer,
-                         wd->enter_serial,
-                         wd->pointer_surface,
-                         x, y);
   if (buffer)
     {
       wl_surface_attach (wd->pointer_surface, buffer, 0, 0);
       wl_surface_set_buffer_scale (wd->pointer_surface, scale);
       wl_surface_damage (wd->pointer_surface,  0, 0, w, h);
       wl_surface_commit (wd->pointer_surface);
+
+      wl_pointer_set_cursor (wd->wl_pointer,
+                             wd->enter_serial,
+                             wd->pointer_surface,
+                             x, y);
+    }
+  else
+    {
+      wl_pointer_set_cursor (wd->wl_pointer,
+                             wd->enter_serial,
+                             NULL,
+                             0, 0);
+
+      wl_surface_attach (wd->pointer_surface, NULL, 0, 0);
+      wl_surface_commit (wd->pointer_surface);
     }
 
   if (wd->grab_cursor)