tree b4a60cd068ff862b6422322a29e9af8203d91371
parent b6bb687fbe7c2494f17c0682e577c6b8dcc961d3
author L. David Baron <dbaron@chromium.org> 1695940935 -0700
committer Blink WPT Bot <blink-w3c-test-autoroller@chromium.org> 1695941895 -0700

Make dir=auto fall back to the parent's directionality rather than ltr.

When dir=auto fails to find text with strong directionality (or a <slot>
element) to determine the directionality of the element, it should fall
back to the directionality that it would have inherited from its parent
(or, for <slot>, its shadow host) rather than falling back to ltr.

This requires updating directionality invalidation to account for the
possibility that elements with dir=auto can inherit directionality.

This is based on the proposed behavior described in:
https://github.com/whatwg/html/issues/3699#issuecomment-951423468
which is in the process of being specified in:
https://github.com/whatwg/html/pull/9554
https://github.com/whatwg/html/pull/9796

This is one of two changes needed to fix the failure of:
external/wpt/html/dom/elements/global-attributes/dir-shadow-41.html
in the still-unlanded WPT PR at
https://github.com/web-platform-tests/wpt/pull/29820

Bug: 576815
Change-Id: I9fc7c85875074ad41704ab45ec70c7632c3f8d31
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4805163
Commit-Queue: David Baron <dbaron@chromium.org>
Reviewed-by: Di Zhang <dizhangg@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1202893}