https://bugs.webkit.org/show_bug.cgi?id=228693
Reviewed by Chris Dumez.
Source/WebCore:
The bug was caused by ResizeObserver::removeObservation removing it from the active targets.
Note that there is nothing in the specification which alludes to this behavior,
and the new behavior is consistent with Firefox and the way IntersectionObserver works:
https://drafts.csswg.org/resize-observer/#dom-resizeobserver-unobserve
To keep elements alive while they're in the active targets but not in the observation targets,
this patch also makes each element of the active observation as opaque roots of ResizeObserver
in ResizeObserver::isReachableFromOpaqueRoots.
Test: resize-observer/resize-observer-keeps-element-of-queued-entry-alive.html
* page/ResizeObserver.cpp:
(WebCore::ResizeObserver::deliverObservations):
(WebCore::ResizeObserver::isReachableFromOpaqueRoots const):
(WebCore::ResizeObserver::removeObservation):
LayoutTests:
Added a regression test.
* resize-observer/resize-observer-keeps-element-of-queued-entry-alive-expected.txt: Added.
* resize-observer/resize-observer-keeps-element-of-queued-entry-alive.html: Added.
Canonical link: https://commits.webkit.org/240178@main
git-svn-id: https://svn.webkit.org/repository/webkit/trunk@280551 268f45cc-cd09-0410-ab3c-d52691b4dbfc
00c08681e9