Branch: refs/heads/main
Home: https://github.com/WebKit/WebKit
Commit: d08faf9fab62fcbe230979774bacbdc53684e816
https://github.com/WebKit/WebKit/commit/d08faf9fab62fcbe230979774bacbdc53684e816
Author: Antoine Quint <[email protected]>
Date: 2024-07-11 (Thu, 11 Jul 2024)
Changed paths:
A
LayoutTests/imported/w3c/web-platform-tests/css/css-animations/display-none-prevents-starting-in-subtree-expected.txt
A
LayoutTests/imported/w3c/web-platform-tests/css/css-animations/display-none-prevents-starting-in-subtree.html
M Source/WebCore/rendering/updating/RenderTreeUpdater.cpp
M Source/WebCore/style/StyleTreeResolver.cpp
M Source/WebCore/style/StyleTreeResolver.h
M Source/WebCore/style/Styleable.cpp
M Source/WebCore/style/Styleable.h
Log Message:
-----------
REGRESSION (276531@main): Content flash when expanding image viewer on eBay
page
https://bugs.webkit.org/show_bug.cgi?id=275739
rdar://128178476
Reviewed by Alan Baradlay.
Listings on eBay can display a photo gallery which is contained within a
subtree where
the `hidden` presentation attribute is toggled to show and hide the gallery.
The `hidden`
attribute really governs whether `display: none` is applied. In that subtree, a
forwards-filling
`opacity` CSS Animation is applied.
Prior to `276531@main`, when `Style::TreeResolver::resolveElement()` would be
called under
`Style::TreeResolver::resolveComposedTree()` for an element with `display:
none`, an empty
`ElementUpdate` would be returned and `resolveComposedTree()` would not process
its children.
In `276531@main`, we modified `resolveElement()` such that this behavior would
not only apply
to elements with a newly-set `display: none` style associated with them,
excluding those with
a cached `display: none` style. This was done in the static function
`affectsRenderedSubtree()`.
This meant that now, if an element within a `display: none` subtree had its
style modified,
`resolveElement()` would be called for that entire subtree when it previously
wouldn't have.
As a result, `createAnimatedElementUpdate()` would now be called and since this
method had
only ever been called for elements not contained within a `display: none`
subtree, it would
not consider that possibility and start CSS Animations in that subtree.
This is what caused the eBay regression because the forwards-filling animation
meant to fade
the photo gallery in would be reapplied soon after the photo gallery was hidden
after an
additional style update, and when that photo gallery would become visible
again, the animation
was already in effect and the gallery did not have the expected computed
`opacity` value.
To fix this, we capture a new `isInDisplayNoneTree` state on the `Parent`
objects created as
we iterate through the composed tree in `resolveComposedTree()`. That new
member identifies
whether that element or a parent has `display: none` set on it. Now we can pass
that state
down to `createAnimatedElementUpdate()` and ultimately to
`Styleable::updateCSSAnimations()`
and ultimately neglect to start new CSS Animations when the element in question
is contained
within a `display: none` subtree.
We also removed the `affectsRenderedSubtree()` changed introduced in
`276531@main` which simply
did not make much sense, and to ensure that elements with `display: none` that
had their style
updated correctly updated their cached `display: none` style, we now return a
non-empty
`ElementUpdate` and add that `ElementUpdate` to `m_update` in
`resolveComposedTree()`.
Finally, we add a new WPT test that reduces the eBay behavior.
*
LayoutTests/imported/w3c/web-platform-tests/css/css-animations/display-none-prevents-starting-in-subtree-expected.txt:
Added.
*
LayoutTests/imported/w3c/web-platform-tests/css/css-animations/display-none-prevents-starting-in-subtree.html:
Added.
* Source/WebCore/rendering/updating/RenderTreeUpdater.cpp:
(WebCore::RenderTreeUpdater::updateElementRenderer):
* Source/WebCore/style/StyleTreeResolver.cpp:
(WebCore::Style::TreeResolver::Parent::Parent):
(WebCore::Style::affectsRenderedSubtree):
(WebCore::Style::TreeResolver::resolveElement):
(WebCore::Style::TreeResolver::resolvePseudoElement):
(WebCore::Style::TreeResolver::createAnimatedElementUpdate):
(WebCore::Style::TreeResolver::pushParent):
(WebCore::Style::TreeResolver::resolveComposedTree):
* Source/WebCore/style/StyleTreeResolver.h:
* Source/WebCore/style/Styleable.cpp:
(WebCore::Styleable::updateCSSAnimations const):
* Source/WebCore/style/Styleable.h:
Canonical link: https://commits.webkit.org/280876@main
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