bug#73862: [PATCH] Add `header-line-active` and `header-line-inactive` faces.

[Eli Zaretskii]

> From: Aaron Jensen <aaronjensen@gmail.com>
> Date: Mon, 23 Dec 2024 13:19:32 -0800
> Cc: Eli Zaretskii <eliz@gnu.org>, trevor.m.murphy@gmail.com, 
> monnier@iro.umontreal.ca, 
>       73862@debbugs.gnu.org, yantar92@posteo.net
> 
> On Mon, Dec 23, 2024 at 2:20 AM, Eshel Yaron <me@eshelyaron.com> wrote:
> 
>  Eli Zaretskii <eliz@gnu.org> writes: 
> 
>  Please try the patch below. If it gives good results, please run with it for 
> awhile, and tell if you see
>  anything unusual or unexpected. 
> 
>  Thanks, so far so good.
> 
> Same for me, it's also working so far.
> 
> Are there any tradeoffs with this approach other than additional code 
> complexity? Any performance
> concerns?

I didn't time the code.  It is a bit more expensive, but I don't know
by how much.  Maybe you could see what happens in a session with lots
and lots of faces and report?