The alias is left there temporarilly and will be removed completely in a later commit where
also components/style/gecko/generated/structs_{debug|release}.rs are re-generated (they still
use the old alias).
We will need to convert from URLValueData to SpecifiedUrl when cloning the
stylo's data from gecko's data. Because the filter structure on gecko has url as
URLValue type. We will use this convert function when interpolating as
discrete also(Bug 1368610).
It's a bit unfortunate the use separate implementations of SpecifiedUrl for Servo
and Gecko, but they're different enough at this point that I don't think it really
makes sense to try to share everything. Splitting them out has some nice
simplifications as well.
I recognize that there's still some potential correctness issues for Servo using
the resolved URI in various places where the original URI may be the right thing,
but I've got too much on my plate to look into that for now.
MozReview-Commit-ID: BeDu93TQ4Ow
