ShorthandSerializer::serializeGridTemplate bails out early if it has to serialize the third version of the shorthand ([ <line-names>? <string> <track-size>? <line-names>? ]+ [ / <explicit-track-list> ]?) and the values were not set from the shorthand. We should be checking these values directly and see if they can be represented in this syntax
<rdar://problem/114224504>
Pull request: https://github.com/WebKit/WebKit/pull/16909
Submitted web-platform-tests pull request: https://github.com/web-platform-tests/wpt/pull/41592
Committed 267155@main (74849b01b119): <https://commits.webkit.org/267155@main> Reviewed commits have been landed. Closing PR #16909 and removing active labels.