...after program restart
GimpContext was always supposed to keep the names of objects (brush,
pattern, font etc.) around even if these objects don't exist, for
cases like refreshing the data in a GimpDataFactory (which worked
fine), but also for deserializing the names of objects which don't
exist *yet* (delayed loading, no-data or whatever).
This commit fixes the delayed loading case (particularly affects fonts):
gimp_context_deserialize_property(): always keep the name of the
object around when it is not found, not only in the no-data case.
gimp_context_copy_property(): always copy the object *and* its name to
the dest context.
Add GimpConfig::duplicate() and ::copy() implementations which chain
up for duplicating/copying all properties and additionally copy all
object names to the new/dest context.
(cherry picked from commit ed1e2b1524)
4ea171c50e