Remove invalidate_maybe_recurse and process_updates from the paintable interface

Replace them with two new functions
_gdk_windowing_{before,after}_process_all_updates() that are called
around the guts of gdk_window_process_all_updates(). Add empty ones
for X11 (nothing more needed), quartz ones will be implemented next.

gdk/x11/gdkwindow-x11.c

@@ -5519,6 +5519,16 @@ _gdk_windowing_window_process_updates_recurse (GdkWindow *window,
   _gdk_window_process_updates_recurse (window, expose_region);
 }
 
+void
+_gdk_windowing_after_process_all_updates (void)
+{
+}
+
+void
+_gdk_windowing_after_process_all_updates (void)
+{
+}
+
 static void
 gdk_window_impl_iface_init (GdkWindowImplIface *iface)
 {