The CSSOM spec tells us to potentially add up to three different IDL
attributes to CSSStyleDeclaration for every CSS property we support:
- A camelCased attribute, where a dash indicates the next character
should be uppercase
- A camelCased attribute for every -webkit- prefixed property, with the
first letter always being lowercase
- A dashed-attribute for every property with a dash in it.
Additionally, every attribute must have the CEReactions and
LegacyNullToEmptyString extended attributes specified on it.
Since we specify every property we support with Properties.json, we can
use that file to generate the IDL file and it's implementation.
We import it from the Build directory with the help of multiple import
base paths. Then, we add it to CSSStyleDeclaration via the mixin
functionality and inheriting the generated class in
CSSStyleDeclaration.
(cherry picked from commit aacf9b08ed8c4286c84145b52fa70f399ed0bdff;
amended to fix tiny conflict in libweb_generators.cmake, and to change
the default value of all gap-related properties from 'auto' to 'normal'
since serenity does not yet have LadybirdBrowser/ladybird#2253 and
cherry-picking that has a pretty long dependency tree. It's easy to
update the test once that is cherry-picked)
When a property is a "legacy name alias", any time it is used in CSS or
via the CSSOM its aliased name is used instead.
(See https://drafts.csswg.org/css-cascade-5/#legacy-name-alias)
This means we only care about the alias when parsing a string as a
PropertyID - and we can just return the PropertyID it is an alias for.
No need for a distinct PropertyID for it, and no need for LibWeb to
care about it at all.
Previously, we had a bunch of these properties, which misused our code
for "logical aliases", some of which I've discovered were not even
fully implemented. But with this change, all that code can go away, and
making a legacy alias is just a case of putting it in the JSON. This
also shrinks `StyleProperties` as it doesn't need to contain data for
these aliases, and removes a whole load of `-webkit-*` spam from the
style inspector.
(cherry picked from commit fdcece2e88b91b9ec6cf63c3466525fb77540316;
amended to:
* resolve a conflict on height: in getComputedStyle-print-all.txt
* run prettier on CSSGeneratedFiles.md)
