It's a little verbose to repeat these in cases like the borders, but if
everything has an initial value, we can guarantee that
`property_initial_value()` will return something! :^)
- `align-items`: `normal` is the initial value in the CSS-ALIGN spec,
but `stretch` is in CSS-FLEXBOX. The FLEXBOX spec is the one we've
actually implemented elsewhere, and ALIGN adds new values with special
syntax, so it's not trivial to add it here.
- `border-spacing`: `0` is equivalent to `0px 0px` and we don't yet
parse the double-value syntax.
- `text-decoration-thickness`: Had the wrong value.
While right now this doesn't save much complexity, it will do once we
care about multiple background layers per node. Then, having a single
repeat value per layer will simplify things.
It also means we can remove the pseudo-property concept entirely! :^)
Previously, `box-shadow: none` would fail to parse, meaning that in this
example:
```css
p {
box-shadow: 20px 10px 5px magenta;
}
p.foo {
box-shadow: none;
}
```
... a `<p class="foo">` would still have a box-shadow, when it should
not have one. Now, we handle the `none` value. :^)
For `number` and `integer` types, you can add a range afterwards to add
a range check, using similar syntax to that used in the CSS specs. For
example:
```json
"font-weight": {
...
"valid-types": [
"number [1,1000]"
],
...
}
```
This limits any numbers to the range `1 <= n <= 1000`.
- The `text-decoration-foo` values now match the spec.
- Added values for `border-foo` since those are needed soon.
- Make `color`'s initial value be `-libweb-palette-base-text`.
In the spec, `fill` and `stroke` are supposed to be a shorthands for
various properties. But since the spec is still a working draft, and
neither Firefox or Chrome support the `fill-color` or `stroke-color`
properties, we'll stick with `fill` and `stroke` as simple colors for
now.
Also, note that SVG expects things in "user units", and we are assuming
that 1px = 1 user unit for now.
This is just to make the CSS parser stop whining when it encounters some
very common properties and identifiers. More work will be required to
actually support these things. :^)
Two CSS quirks are specced to only apply to specific properties:
- The hashless hex color quirk
https://quirks.spec.whatwg.org/#the-hashless-hex-color-quirk
- The unitless length quirk
https://quirks.spec.whatwg.org/#the-unitless-length-quirk
These are now represented in `Properties.json` like so:
```json
"property-name-here": {
"quirks": [
"hashless-hex-color",
"unitless-length"
]
}
```
Every property that either of those two quirks applies to is included in
`Properties.json` and now has their quirks listed. :^)
We already include the inheritance for each property in Properties.json,
so made sense to use that instead of a list in StyleResolver.
Added `inherited: true` to a couple of properties to match the previous
code's behavior. One of those had a FIXME which I've moved to the JSON
file, which is hacky, but it works.
The background-repeat value may be specified as either one- or two-value
identifiers (to be interpreted as horizontal and vertical repeat). This
adds two pseudo-properties, background-repeat-x and background-repeat-y,
to handle this. One-value identifiers are mapped to two-value in
accordance with the spec.
