Instead of on-demand resolvage, we now resolve during lookup. The step
is done via
_gtk_css_style_property_compute_value()
which currently calls into
_gtk_css_style_compute_value()
That function has all the old resolving machinery.
The only part missing for now is the handling of win32 code. It will be
added back later.
This will be used as a base both for parsing text-shadow and box-shadow
properties. The type is private, as there's no real use in exporting
this in a public API.
https://bugzilla.gnome.org/show_bug.cgi?id=649314
