And use it in WebCore/loader/HeaderFieldTokenizer, WebCore/platform/network/HTTPParsers, WebCore/platform/network/RFC7230, WebCore/loader/LinkHeader.cpp, and WebCore/html/track/WebVTTParser (and dependencies). Also replace isASpace in WebCore/html/track/WebVTTParser with isASCIIWhitespace.
<rdar://problem/108426795>
Pull request: https://github.com/WebKit/WebKit/pull/13081
Committed 263354@main (2ae8e53cdb4a): <https://commits.webkit.org/263354@main> Reviewed commits have been landed. Closing PR #13081 and removing active labels.