Going to factor shorthand serialization out of the StyleProperties class. One benefit of this is that we will be able to use the logic in computed style too.
<rdar://problem/104517006>
Pull request: https://github.com/WebKit/WebKit/pull/8956
Committed 259211@main (66b28324b8b9): <https://commits.webkit.org/259211@main> Reviewed commits have been landed. Closing PR #8956 and removing active labels.