[webkit-changes] [WebKit/WebKit] 1c6a14: [scroll-anchoring] Add extra checks to viablePrior...

[Nikos Mouchtaris]

  Branch: refs/heads/main
  Home:   https://github.com/WebKit/WebKit
  Commit: 1c6a14248561e2b8b643d85f75968d761940008f
      https://github.com/WebKit/WebKit/commit/1c6a14248561e2b8b643d85f75968d761940008f
  Author: Nikolaos Mouchtaris <nmouchtaris at apple.com>
  Date:   2023-12-08 (Fri, 08 Dec 2023)

  Changed paths:
    A LayoutTests/imported/w3c/web-platform-tests/css/css-scroll-anchoring/focused-element-outside-scroller-expected.txt
    A LayoutTests/imported/w3c/web-platform-tests/css/css-scroll-anchoring/focused-element-outside-scroller.html
    M Source/WebCore/page/scrolling/ScrollAnchoringController.cpp
    M Source/WebCore/page/scrolling/ScrollAnchoringController.h

  Log Message:
  -----------
  [scroll-anchoring] Add extra checks to viablePriorityCandidateForElement to ensure a sensible priority candidate
https://bugs.webkit.org/show_bug.cgi?id=266096
rdar://119203528

Reviewed by Simon Fraser.

Add checks to ensure that the priority candidate is a descendant of the current scroller and that it
is not an excluded subtree.

* LayoutTests/imported/w3c/web-platform-tests/css/css-scroll-anchoring/focused-element-outside-scroller-expected.txt: Added.
* LayoutTests/imported/w3c/web-platform-tests/css/css-scroll-anchoring/focused-element-outside-scroller.html: Added.
* Source/WebCore/page/scrolling/ScrollAnchoringController.cpp:
(WebCore::ScrollAnchoringController::didFindPriorityCandidate):

Canonical link: https://commits.webkit.org/271783@main