[css-pseudo] Apply ::marker styles to markers

Currently markers are assigned a mostly empty style, it just inherits
from the list item and has some customizations like `display`.

This patch makes them use the style of the ::marker pseudo-element.
The inheritance is also from the list item, and the customizations are
applied afterwards.

The change only affects markers originated by real elements. Markers
originated by ::before or ::after pseudo-elements should get the styles
from ::before::marker or ::after::marker, but this will be addressed in
a follow-up patch.

Spec: https://drafts.csswg.org/css-pseudo-4/#marker-pseudo



Change-Id: Ide2fbc344e4732257044ebd3e7966906af21c434
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1893265
Reviewed-by: Rune Lillesveen <futhark@chromium.org>
Commit-Queue: Oriol Brufau <obrufau@igalia.com>
Cr-Commit-Position: refs/heads/master@{#711883}
5 files changed