[mutter] xwayland: Fix windows disappearing on reparenting

[Rui Matos <rtcm src gnome org>]

commit 69c267b1424bcba2cf0f0bb6ed4e3d02b374f05f
Author: Rui Matos <tiagomatos gmail com>
Date:   Fri Sep 25 16:18:55 2015 +0200

    xwayland: Fix windows disappearing on reparenting
    
    If the wayland surface isn't available yet when we process the
    WL_SURFACE_ID ClientMessage, we schedule a later function to try the
    association again after we get a chance to process wayland requests.
    
    This works fine except on cases where the MetaWindow already had a
    previous surface attached (i.e. when the xwindow is reparented) since
    we only break the existing association on the later function which
    means that when processing the old surface's destruction we destroy
    the MetaWindow and cancel the pending later function leaving us
    without a MetaWindow and an invisible surface.
    
    Fix this by detaching the old surface as soon as possible so that the
    MetaWindow survives.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=743339

 src/wayland/meta-xwayland.c |   17 ++++++++++-------
 1 files changed, 10 insertions(+), 7 deletions(-)
---
diff --git a/src/wayland/meta-xwayland.c b/src/wayland/meta-xwayland.c
index dc7e83f..179b94c 100644
--- a/src/wayland/meta-xwayland.c
+++ b/src/wayland/meta-xwayland.c
@@ -55,13 +55,6 @@ associate_window_with_surface (MetaWindow         *window,
 {
   MetaDisplay *display = window->display;
 
-  /* If the window has an existing surface, like if we're
-   * undecorating or decorating the window, then we need
-   * to detach the window from its old surface.
-   */
-  if (window->surface)
-    window->surface->window = NULL;
-
   if (!meta_wayland_surface_assign_role (surface,
                                          META_TYPE_WAYLAND_SURFACE_ROLE_XWAYLAND))
     {
@@ -88,6 +81,16 @@ associate_window_with_surface_id (MetaXWaylandManager *manager,
 {
   struct wl_resource *resource;
 
+  /* If the window has an existing surface, like if we're
+   * undecorating or decorating the window, then we need
+   * to detach the window from its old surface.
+   */
+  if (window->surface)
+    {
+      meta_wayland_surface_set_window (window->surface, NULL);
+      window->surface = NULL;
+    }
+
   resource = wl_client_get_object (manager->client, surface_id);
   if (resource)
     {