tree dc1a870c0b025616cb558795a776c9836be9868f
parent 94ebf348ec9f6ce2eb3d4ac8c4bc2cef1b82de4a
author Xiaocheng Hu <xiaochengh@chromium.org> 1688684461 -0700
committer Blink WPT Bot <blink-w3c-test-autoroller@chromium.org> 1688685525 -0700

[anchor-position] Implement 'position-fallback-bounds'

This patch implements the 'position-fallback-bounds' property by:
(1) Also checking the additional fallback-bounds rect in
    NGOutOfFlowLayoutParts::CalculateOffset()
(2) Also keep track of the scroll offset of the additional bounds rect
    in AnchorScrollData, and use that as an input (1)
(3) Augments the existing non-overflowing scroll range structure with
    an additional range (see the NonOverflowingScrollRange struct) to
    help determine whether the additional fallback-bounds rect is
    overflown.

Spec: https://drafts.csswg.org/css-anchor-position-1/#fallback-bounds

Fixed: 1455557
Change-Id: I60cd8c22e84d5d70d7f1f73258aa8d60c30480f4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4655384
Commit-Queue: Xiaocheng Hu <xiaochengh@chromium.org>
Reviewed-by: Ian Kilpatrick <ikilpatrick@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1166807}