Fields 'allocation' and 'server_allocation' are surface specific. Fields
'saved_allocation', 'min_allocation', and 'pending_allocation' are
window specific, and will not be moved.
Field 'toysurface' is naturally surface specific, since it provides the
backing storage for the wl_surface.
Signed-off-by: Pekka Paalanen <ppaalanen@gmail.com>