xwayland: Pass MetaWaylandCompositor pointer when initializing

This way we can initialize without having any way to retrieve it via
some global variable. This isn't needed now, but will be once Wayland
infrastructure initializiation is done in a single step.

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1863>

src/wayland/meta-wayland.c

@@ -558,6 +558,7 @@ meta_wayland_compositor_setup (MetaWaylandCompositor *compositor)
       g_autoptr (GError) error = NULL;
 
       if (!meta_xwayland_init (&compositor->xwayland_manager,
+                               compositor,
                                compositor->wayland_display,
                                &error))
         g_error ("Failed to start X Wayland: %s", error->message);

src/wayland/meta-xwayland-private.h

@@ -25,9 +25,10 @@
 #include "wayland/meta-wayland-private.h"
 
 gboolean
-meta_xwayland_init (MetaXWaylandManager  *manager,
-                    struct wl_display    *display,
-                    GError              **error);
+meta_xwayland_init (MetaXWaylandManager    *manager,
+                    MetaWaylandCompositor  *compositor,
+                    struct wl_display      *display,
+                    GError                **error);
 
 void
 meta_xwayland_complete_init (MetaDisplay *display,

src/wayland/meta-xwayland.c

@@ -568,6 +568,7 @@ xserver_died (GObject      *source,
         meta_display_shutdown_x11 (display);
 
       if (!meta_xwayland_init (&compositor->xwayland_manager,
+                               compositor,
                                compositor->wayland_display,
                                &error))
         g_warning ("Failed to init X sockets: %s", error->message);
@@ -1137,9 +1138,10 @@ meta_xwayland_stop_xserver (MetaXWaylandManager *manager)
 }
 
 gboolean
-meta_xwayland_init (MetaXWaylandManager  *manager,
-                    struct wl_display    *wl_display,
-                    GError              **error)
+meta_xwayland_init (MetaXWaylandManager    *manager,
+                    MetaWaylandCompositor  *compositor,
+                    struct wl_display      *wl_display,
+                    GError                **error)
 {
   MetaX11DisplayPolicy policy;
   int display = 0;