2006-04-11  Anders Carlsson  <andersca@imendio.com>

        * gdk/gdkinternals.h:
        * gdk/gdkwindow.c:
        (_gdk_paintable_get_type):
        (gdk_window_begin_paint_region):
        (gdk_window_end_paint):
        (gdk_window_process_updates):
        (gdk_window_invalidate_maybe_recurse):
        Add new GdkPaintable interface which implementation objects can
        implement in order to override gdk painting functions.