We had a partial implementation of transformation function interpolation
that did not support numerical interpolation of simple functions (e.g.
`scale(0)` -> `scale(1)`). This refactors the interpolation to follow
the spec more closely.
Gains us 267 WPT subtest passes in `css/css-transforms`.
Fixes#6774.
There are some non-math functions (such as tree counting functions)
which we should allow within `calc()`s . This commit implements the
initial infrastructure for this.
We don't yet parse any of these non-math functions in
`parse_a_calculation` so there is no functional change.
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. 😅
If a property is uses discrete interpolation and TransitionBehavior is
not set to `AllowDiscrete` that property should be non-transitionable.
This is now true for properties whose animation type is not discrete,
but the animation type falls back to discrete.
