A few things fall out of this:
- We no longer need to templatize our color-stop list types.
- A bit more code is required to resolve gradient data.
This results in a slightly different rendering for a couple of the test
gradients, with a larger difference between macOS and Linux. I've
expanded the fuzziness factor to cover for it.
When setting style to a CSSStyleValue we need to convert it to a
StyleValue. If we already have one, we might as well use it avoid the
work of serialization and re-parsing.
I realised I misunderstood what "constructed from a USVString" means, so
I've adjusted based on that. It does raise a question on what the source
USVString is if that string resulted in multiple CSSStyleValues being
created - see the linked issue.
