bug#21012: 25.0.50; eww: last char of a line sometimes not fully visible

[Eli Zaretskii <eliz@gnu.org>]

> From: Michael Heerdegen <michael_heerdegen@web.de>
> Cc: 21012@debbugs.gnu.org
> Date: Sat, 11 Jul 2015 14:02:42 +0200
> 
> > It should be possible, in principle, to write something similar to
> > posn-at-point that would not depend on the text being visible, or
> > rewrite posn-at-point to free it from this limitation, but we don't
> > have such a function at this time.  Maybe we should.
> 
> Of course would that be useful, not only for this issue.  But I guess it
> would be a lot of work.

Actually, it's not a lot of work.  Patches welcome, and I will look
into doing that if no one does until I have enough free time (which
currently could take a while).

> I try now what you suggested, subtracting one more column width when
> calculating `shr-internal-width'.  I.e., I subtract one more
> `frame-char-width' now.  Looks good so far.  I'll use it for some time
> and tell you what I think.
> 
> So, here is what I'm testing, based on your first patch:

Thanks.