tree f67323b6396eebca6f63cf0f9b488b6609c18c8d
parent be2693965b5b1d4dacca6e57ff00ea01272fa2d6
author Philip Rogers <pdr@chromium.org> 1712163545 -0700
committer Blink WPT Bot <blink-w3c-test-autoroller@chromium.org> 1712164323 -0700

[css-anchor-position] Support basic position-visibility: anchors-visible

This patch implements basic support for position-visibility:
anchors-visible with a single anchor. There is active discussion about
whether to track the visibility of multiple anchors at:
https://github.com/w3c/csswg-drafts/issues/7758#issuecomment-2026137829.
The high-level approach in this patch is to use a post-layout
intersection observer for the tracked anchor. On visibility changes, the
anchored element's paint layer is updated via
`PaintLayer::SetInvisibleForPositionVisibility`.

Spec:
https://github.com/w3c/csswg-drafts/issues/7758#issuecomment-1965540529

Bug: 329703412
Change-Id: Icedcb43510a0c6a491cf463e7dc8a114ab7abf5f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5410539
Commit-Queue: Xianzhu Wang <wangxianzhu@chromium.org>
Auto-Submit: Philip Rogers <pdr@chromium.org>
Reviewed-by: Xianzhu Wang <wangxianzhu@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1281911}