Face realization (was: face-remapping patch)

[Stefan Monnier]

> My experience with this infrastructure, using `color-themes' and
> plenty of frames, has been less than stellar.  When switching color
> themes, more and more faces get defined during the session. This slows
> the creation of frames down to the point where it takes 2+ seconds to
> create one.  I had to install a patch in my own version to keep it
> from making frame-specific copies of all global faces for each
> new  frame.

This is a separate problem (at least, given the current code).  It would
be good to try and realize faces lazily as they get encountered rather
than realize them all everytime we create a new frame.

Also, as you point out, there's a gross inefficiency in that most faces
are really terminal-local rather than frame-local (after all, the
defface spec does not allow per-frame customizations), so we should
share the resulting realized faces.  If you have a patch for it, maybe
you should post it here,


        Stefan