We had `parse_calculated_value()` which parsed the contents of `calc()`,
and `parse_dynamic_value()` which parsed any math function, both of
which produce a CalculatedStyleValue, but return a plain StyleValue.
This was confusing, so let's combine them together, and return a
CalculatedStyleValue.
This also makes the other math functions work in
`StyleComputer::expand_unresolved_values()`.
This would cause a nullptr-deref during painting of invalid
linear-gradients, such as `linear-gradient(top, #f8f9fa, #ececec)`
found in googles sign-in button
We now keep the color value as a StyleValue up until we go to paint the
gradient, which makes `currentColor` work, along with any other color
values that can't be immediately converted into a `Gfx::Color` while
parsing.
Stop worrying about tiny OOMs. Work towards #20449.
While going through these, I also changed the function signature in many
places where returning ThrowCompletionOr<T> is no longer necessary.
We now apply MathML's default user agent style sheet along with other
default styles. This sheet is not mixed in with the other styles in
CSS/Default.css because it is a namespaced stylesheet and so has to
be its own sheet.
We don't yet set the Document's target element in most cases, so this
does not function very well. But that will improve once we *do* set it,
which involves a more complete Navigables implementation.
For now, we parse these, but don't actually consider the namespace when
matching them. `DOM::Element` does not (yet) store attribute namespaces
so we can't check what they are.
Holding the `prefix` as a StringView meant it pointed at string data
held by `token`. `token` gets reassigned shortly afterwards, meaning
`prefix` would hold invalid character data.
This is basically a name with a namespace prefix. It will be used for
adding namespaces to Universal, TagName, and Attribute selectors.
For convenience, this can also optionally parse/store the `*` wildcard
character as the name.
We got some errors while loading https://twinings.co.uk/ about this
interface missing, and it looked fairly simple so I sketched it out.
Note that I did leave some FIXMEs where it's not clear exactly which
metrics we should be returning.
We were already parsing non-function-syntax :host, so let's also do
the :host(...) variant. Note that we don't have matching for these yet.
This fixes many issues on sites generated by Wix, as they often have
selector lists that include some :host() selector, and we'd reject the
entire rule after failing to parse it.
Instead, perform the filtering for each rule as we go. This avoids
creating a separate list of rules, which was ~5% of runtime when
mousing around on the Discord web interface.
...along with `outline-color`, `outline-style`, and `outline-width`.
This re-uses the existing border-painting code, which seems to work well
enough!
This replaces the previous code for drawing focus-outlines, with generic
outline painting for any elements that want it. Focus outlines are now
instead supported by this code in Default.css:
```css
:focus-visible {
outline: auto;
}
```
Don't give up if we can't parse that single value for the property
directly, but let the parsing code carry on and see if we can produce a
CompositeStyleValue.
