[mutter] backends/x11: Make the X11 backend derivable

[Jonas Ådahl <jadahl src gnome org>]

commit d188949101b4b6328741645d15ebdd3274b1570d
Author: Jonas Ådahl <jadahl gmail com>
Date:   Mon Dec 5 18:33:19 2016 +0800

    backends/x11: Make the X11 backend derivable
    
    Make the X11 backend derivable so that we can base a nested test backend
    on it.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=777732

 src/backends/meta-monitor-manager-private.h |    2 ++
 src/backends/x11/meta-backend-x11.c         |    5 -----
 src/backends/x11/meta-backend-x11.h         |    9 +++++++--
 3 files changed, 9 insertions(+), 7 deletions(-)
---
diff --git a/src/backends/meta-monitor-manager-private.h b/src/backends/meta-monitor-manager-private.h
index 7e61d0e..3328870 100644
--- a/src/backends/meta-monitor-manager-private.h
+++ b/src/backends/meta-monitor-manager-private.h
@@ -278,6 +278,8 @@ struct _MetaOutputInfo {
 #define META_IS_MONITOR_MANAGER_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE ((klass),  META_TYPE_MONITOR_MANAGER))
 #define META_MONITOR_MANAGER_GET_CLASS(obj)  (G_TYPE_INSTANCE_GET_CLASS ((obj),  META_TYPE_MONITOR_MANAGER, 
MetaMonitorManagerClass))
 
+G_DEFINE_AUTOPTR_CLEANUP_FUNC (MetaMonitorManager, g_object_unref)
+
 struct _MetaMonitorManager
 {
   MetaDBusDisplayConfigSkeleton parent_instance;
diff --git a/src/backends/x11/meta-backend-x11.c b/src/backends/x11/meta-backend-x11.c
index a545859..9237f27 100644
--- a/src/backends/x11/meta-backend-x11.c
+++ b/src/backends/x11/meta-backend-x11.c
@@ -55,11 +55,6 @@
 #include "display-private.h"
 #include "compositor/compositor-private.h"
 
-struct _MetaBackendX11
-{
-  MetaBackend parent;
-};
-
 typedef enum {
   /* We're a traditional CM running under the host. */
   META_BACKEND_X11_MODE_COMPOSITOR,
diff --git a/src/backends/x11/meta-backend-x11.h b/src/backends/x11/meta-backend-x11.h
index b24e518..8bb3388 100644
--- a/src/backends/x11/meta-backend-x11.h
+++ b/src/backends/x11/meta-backend-x11.h
@@ -32,8 +32,13 @@
 #include "backends/x11/meta-clutter-backend-x11.h"
 
 #define META_TYPE_BACKEND_X11 (meta_backend_x11_get_type ())
-G_DECLARE_FINAL_TYPE (MetaBackendX11, meta_backend_x11,
-                      META, BACKEND_X11, MetaBackend)
+G_DECLARE_DERIVABLE_TYPE (MetaBackendX11, meta_backend_x11,
+                          META, BACKEND_X11, MetaBackend)
+
+struct _MetaBackendX11Class
+{
+  MetaBackendClass parent_class;
+};
 
 Display * meta_backend_x11_get_xdisplay (MetaBackendX11 *backend);