Previously we would just set the attributes to the serialized
descriptors, even if they were the empty string.
We now apply defaults when we have empty descriptors and apply parsing
logic from the various `set_*` methods (only applicable to `font-family`
so far where we now extract the value from either a string or a
custom-ident)
Fixes an issue in some css/css-shapes WPT tests where we weren't
properly matching fonts.
The spec states that updates to descriptors in a `@font-face` rule
should be reflected in the connected `FontFace`'s attributes.
Previously this was achieved by directly accessing those descriptors
when calling the attribute getters, but this has a couple of issues:
a) The changes are only reflected if we use the accessors (i.e.
`FontFace::family()` rather than `FontFace::m_family`) which isn't
the case everywhere
b) The changes aren't persisted after the `FontFace` is disconnected
from it's `CSSFontFaceRule`
To fix these issues we now reparse and store the `FontFace`'s attributes
whenever the `CSSFontFaceRule`'s descriptors change.
This also rearranges the code to follow the spec better: We create an
empty FontFace first and then fill it in, instead of creating it
fully-formed at the end.
Both `@supports` and `@font-face` need this. There may be some automatic
way of querying whether our renderer supports these, but I couldn't
figure it out, so here's a basic hard-coded list. I think the font-tech
list has false negatives, as I don't know enough about fonts to
determine what we support accurately.
Resulting in a massive rename across almost everywhere! Alongside the
namespace change, we now have the following names:
* JS::NonnullGCPtr -> GC::Ref
* JS::GCPtr -> GC::Ptr
* JS::HeapFunction -> GC::Function
* JS::CellImpl -> GC::Cell
* JS::Handle -> GC::Root
