bug#53636: 29.0.50; face-remapping broken on master

[martin rudalics]

>> And what happens when you call make-frame from another buffer is not a
>> bug?  Is face-remapping-alist supposed to affect the buffer in which
>> it is set on all frames or just on the single frame where
>> face-remap-add-relative was called?
>
> I'm not sure.  But the current behaviour (affecting all buffers on the
> new frame) has to be a bug.

Face remapping has never been properly synchronized with windows and
frames.  What's needed is a simple hierarchy window > window's buffer >
window's frame where the first should be implemented with the help of a
'face-remapping' window parameter and the last with the help of a
'face-remapping' frame parameter.  Just like we (should) do for things
like the scroll bars or fringes.  But we need a consensus on this first.

martin