[mutter] xwayland: Init DnD on every Xwayland start

[Marge Bot <marge-bot src gnome org>]

commit de8927e075b43419e0ab7246e1c305af8d6532b2
Author: Olivier Fourdan <ofourdan redhat com>
Date:   Tue Mar 15 14:33:22 2022 +0100

    xwayland: Init DnD on every Xwayland start
    
    Currently, meta_xwayland_shutdown_dnd() is called from the handler
    on_x11_display_closing() triggered from the signal "x11-display-closing"
    hooked up from meta_xwayland_init_display().
    
    Once the signal has been triggered, on_x11_display_closing() removes the
    signal handler, disconnecting from the signal.
    
    As meta_xwayland_init_display() is called from meta_display_new() which
    is issued only once, the signal handler is not restored again.
    
    As a result, meta_xwayland_shutdown_dnd() is not called anymore after
    Xwayland has been restarted, but meta_xwayland_init_dnd() will check and
    assert that the manager's DND object is NULL.
    
    Basically, restarting Xwayland more that once will trigger an assertion
    failure in mutter. That's even more of a problem with autoclose-xwayland
    where Xwayland is expected to terminate when there is no meaningful X11
    client remaining, which can happen multiple times during the lifetime
    of a user session.
    
    To make sure that meta_xwayland_init_display() is called for every new
    instance of Xwayland, simply keep the signal hooked in place by not
    disconnecting it when triggered.
    
    This reverts commit 9a10b8ff94cc9506a4ecd8ade7489fa9a5af406a.
    
    Even though, originally, this issue was first introduced with commit
    b4fe1fdd95d52e8625c66ded1ec7162371dcf32b ("xwayland: Make setup/teardown
    a bit more symmetrical") which didn't actually kept 'x11-display-setup'
    and 'x11-display-closing' connected.
    
    Closes: https://gitlab.gnome.org/GNOME/mutter/-/issues/2168
    Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2339>

 src/wayland/meta-xwayland.c | 3 ---
 1 file changed, 3 deletions(-)
---
diff --git a/src/wayland/meta-xwayland.c b/src/wayland/meta-xwayland.c
index 33058fcfb9..dc96b606fd 100644
--- a/src/wayland/meta-xwayland.c
+++ b/src/wayland/meta-xwayland.c
@@ -1067,9 +1067,6 @@ on_x11_display_closing (MetaDisplay         *display,
   g_signal_handlers_disconnect_by_func (meta_monitor_manager_get (),
                                         monitors_changed_cb,
                                         NULL);
-  g_signal_handlers_disconnect_by_func (display,
-                                        on_x11_display_closing,
-                                        manager);
 }
 
 static void