Use StyleValue's computational-independence predicate when deciding
which specified values to retain for inherited-style recomputation.
Compound values such as shadows, filters, lists, and calc trees now
reuse their existing dependency tracking instead of the old bare-length
check.
Treat missing tuple entries and keyword-only edge offsets as
computationally independent. These nullable slots are part of the
parsed value representation, and the inherited dependency tracking now
uses the shared computational-independence query for specified values.
Add viewport resize coverage for media query changes that update root
font metrics while a descendant uses font-relative lengths inside
box-shadow and filter values.
Previously, some StyleValues created a large number of intermediate
strings during serialization. Passing a StringBUilder into the
serialization function allows us to avoid a large number of these
unnecessary allocations.
`EdgeStyleValues` which consist of an offset of a `calc()`s which
resolves to 50% should be considered "centered" for
`SerializationMode::ResolvedValue` for the purpose of omitting the
position value from gradient serialization.
As well as being required to implement absolutization this also means we
now bypass a limitation with `LengthPercentage` where we would always
use `SerializationMode::Normal` for the constituent lengths which gains
us some WPT passes
This reverts 0e3487b9ab.
Back when I made that change, I thought we could make our StyleValue
classes match the typed-om definitions directly. However, they have
different requirements. Typed-om types need to be mutable and GCed,
whereas StyleValues are immutable and ideally wouldn't require a JS VM.
While I was already making such a cataclysmic change, I've moved it into
the StyleValues directory, because it *not* being there has bothered me
for a long time. 😅
