Tentative, but it is more correct and made miri happier.

Differential Revision: https://phabricator.services.mozilla.com/D183625

ThinArc is way more complex than it needs to be, and miri complains
about various things when using the selectors crate with it.

This doesn't fully fix miri, but it gets much closer. ThinArc becomes
just an alias for Arc<HeaderSlice<>>. This allows to simplify the
bindings to ArcSlice too, since now the existing Arc<> code can just be
used.

Differential Revision: https://phabricator.services.mozilla.com/D183011

Bug 1837700 comment 14 is right. I can reproduce it by toggling off
scroll-anchoring by pref, and accessing:

  data:text/html,<div contenteditable>

So that we load contenteditable.css which hits the issue.

Differential Revision: https://phabricator.services.mozilla.com/D182666

Introduce LineWidth (which doesn't snap) and let BorderSideWidth
wrap it and actually do the snapping.

Differential Revision: https://phabricator.services.mozilla.com/D180845

Even tho https://github.com/rust-lang/rust/issues/112337 is IMO a rust
bug, it's easy to work around in our code and it doesn't really affect
expressiveness.

Differential Revision: https://phabricator.services.mozilla.com/D180065

Backed out changeset 8752ecf83874 (bug 1804761) for causing failures on content-visibility-070.html. CLOSED TREE

Bug 1804761 - Make content-visibility: auto forces contain-intrinsic-size to gain an auto value, r=emilio,Oriol

When the content having `content-visibility: auto` and the specific value for `contain-intrinsic-size` is slightly out of the viewport,
its computed value keeps changing.
This patch makes `content-visibilty: auto` forces `contain-intrinsic-size` to gain an auto value to solve this issue.

Differential Revision: https://phabricator.services.mozilla.com/D174583

Backed out changeset 9e2c7d3018de (bug 1804761) for causing wpt failures on content-visibility-068.html CLOSED TREE

Now it supports "normal" keyword. Also, offset-position doesn't create
stacking context and it doesn't have offset transform, so we can
simplify CompareMotionValues() a little bit.

Note: We don't have to add test in [1] because Blink added one to WPT
upstream repo already.

[1] css/motion/parsing/offset-position-parsing-valid.html

Note: the usage of offset-position is in other bugs.

Differential Revision: https://phabricator.services.mozilla.com/D179623

Bug 1804761 - Make content-visibility: auto forces contain-intrinsic-size to gain an auto value, r=emilio,Oriol

When the content having `content-visibility: auto` and the specific value for `contain-intrinsic-size` is slightly out of the viewport,
its computed value keeps changing.
This patch makes `content-visibilty: auto` forces `contain-intrinsic-size` to gain an auto value to solve this issue.

Differential Revision: https://phabricator.services.mozilla.com/D174583

Make the computed value of border-like properties app units (which is
effectively what happens in Gecko already), and clamp at computed value
time.

Differential Revision: https://phabricator.services.mozilla.com/D179481

And add some bindings support to it, which will be used by the next
patch.

Differential Revision: https://phabricator.services.mozilla.com/D178768

$ find servo -name '*.rs' | xargs rustup run nightly rustfmt

Depends on D179380

Differential Revision: https://phabricator.services.mozilla.com/D179381

The std lib has had that macro for a while.

Depends on D179379

Differential Revision: https://phabricator.services.mozilla.com/D179380

Use from_bits_retain where possible to save a few instructions here and there
while at it.

Differential Revision: https://phabricator.services.mozilla.com/D179379

Useless by the reason described at the end of the comment, we no longer
have such a flag.

Differential Revision: https://phabricator.services.mozilla.com/D179269

Anything that doesn't need interior mutability doesn't need Locked<>
around it.

Depends on D179059

Differential Revision: https://phabricator.services.mozilla.com/D179060

This makes me a bit less uncomfortable about the previous changes :)

Note that some of this code gets modified in the following patch.

Differential Revision: https://phabricator.services.mozilla.com/D179059

Depends on D179038

Differential Revision: https://phabricator.services.mozilla.com/D179039

Differential Revision: https://phabricator.services.mozilla.com/D179038

Bug 1793012: Correct style sharing handling for any element that considered `:has()` in selector matching. r=emilio

For any element that anchors a `:has()` selector (i.e. Matches a selector that
contains a `:has()` on its rightmost side), we prevent style sharing altogether,
as evaluation of the `:has()` selector is required in the first place to
determine style sharing.

On the other hand, any element matching a rule containing `:has()` without
anchoring it can do style sharing for siblings, but not cousins.

Differential Revision: https://phabricator.services.mozilla.com/D176836

Bug 1834674 - [css-properties-values-api] Share PropertyRule instance when cloning CssRule::Property r=emilio

Differential Revision: https://phabricator.services.mozilla.com/D178892

This is necessary to properly report changes in our document.

The remaining failures are about change event scheduling, which is a
pre-existing issue. Will fix, but in a separate bug.

Differential Revision: https://phabricator.services.mozilla.com/D178917

If this happens again, it might be worth not matching rather than
potentially crashing. Though I guess crashing is a very good way getting
it reported soon...

Differential Revision: https://phabricator.services.mozilla.com/D178921

Differential Revision: https://phabricator.services.mozilla.com/D178920

Bug 1833403 - Simplify some appearance code. r=stransky,mac-reviewers,handyman,devtools-reviewers,mstange

I was looking into simplifying our scrollbar styles:

 * StyleAppearance::Resizer is not used in content, and some of the
   values were only for <xul:window> which are not supported anymore.

 * Statusbarpanel and Resizerpanel aren't used. Statusbar is only used
   once on macOS so we only need to keep it there.

Differential Revision: https://phabricator.services.mozilla.com/D178374

This adds two prefs to configure the parallel traversal work item size
and kick-off threshold, but otherwise shouldn't change behavior.

I switched from iterator generics to just a slice while at it, mostly
for simplicity, but there is a trade-off:

 * When switching from sequential to parallel traversal, we potentially
   pay the price of memmoving the VecDeque around once to make them a
   contiguous slice.

 * However we win in the common case of the smaller-than-work-unit size
   in which case we no longer need to copy stuff to a WorkItem. So I
   think overall this should be an improvement.

Differential Revision: https://phabricator.services.mozilla.com/D178656

Backed out changeset f020820671c4 (bug 1833403) for causing reftest failures on resizer-bottomend.xhtml. CLOSED TREE

Bug 1833403 - Simplify some appearance code. r=stransky,mac-reviewers,handyman,devtools-reviewers,mstange

I was looking into simplifying our scrollbar styles:

 * StyleAppearance::Resizer is not used in content, and some of the
   values were only for <xul:window> which are not supported anymore.

 * Statusbarpanel and Resizerpanel aren't used. Statusbar is only used
   once on macOS so we only need to keep it there.

Differential Revision: https://phabricator.services.mozilla.com/D178374

Bug 1834144 - Make stylo thread pool size configurable via pref rather than just env. r=smaug,perftest-reviewers,jgraham,afinder

Remove a variety of code which we don't use to change the pool size. We
can just use the pref as needed in the future.

Differential Revision: https://phabricator.services.mozilla.com/D178575

Added NaN/inf serialization of <number> and changed calc() code to not
remove NaN/infinity in code using it.

This change is unfortunately imperfect as some things using <number>
still refuse to serialize NaN/infinity for some reason (scale()?), but
this bug/patch is just for <number> so leaving that out of scope for this.

Also added new WPT test file for number NaN/inf serialization based
on existing serialization tests (all pass already!).

5 other WPT subtests now newly pass.

Differential Revision: https://phabricator.services.mozilla.com/D178587

Backed out changeset e2d6154400a7 (bug 1833403) for causing reftest failures on resizer-bottomend.xhtml

Removed overflow-block optional-paged value and reftesting as it was
removed from the spec in 2020: https://github.com/w3c/csswg-drafts/issues/5287

1 WPT subtest now newly passes.

WPT tests: https://wpt.fyi/results/css/mediaqueries/test_media_queries.html

Differential Revision: https://phabricator.services.mozilla.com/D178710

Bug 1833403 - Simplify some appearance code. r=stransky,mac-reviewers,handyman,devtools-reviewers,mstange

I was looking into simplifying our scrollbar styles:

 * StyleAppearance::Resizer is not used in content, and some of the
   values were only for <xul:window> which are not supported anymore.

 * Statusbarpanel and Resizerpanel aren't used. Statusbar is only used
   once on macOS so we only need to keep it there.

Differential Revision: https://phabricator.services.mozilla.com/D178374

Bug 1833540 - [css-properties-values-api] Implement parsing and serialization for @property at-rule r=emilio

Implemented behind the new properties-and-values pref.

Support for the CSSPropertyRule WebIDL interface is also added in this
patch, because until it's added, any attempt to access the rule using
the CSSOM would crash the browser.

Depends on D178268

Differential Revision: https://phabricator.services.mozilla.com/D178270

Added NaN/inf serialization of <number> and changed calc() code to not
remove NaN/infinity in code using it.

This change is unfortunately imperfect as some things using <number>
still refuse to serialize NaN/infinity for some reason (scale()?), but
this bug/patch is just for <number> so leaving that out of scope for this.

Also added new WPT test file for number NaN/inf serialization based
on existing serialization tests (all pass already!).

5 other WPT subtests now newly pass.

Differential Revision: https://phabricator.services.mozilla.com/D178587