XMLHttpRequest.open should use USVString as mentioned in the FIXMEs and the spec [1]. [1] https://xhr.spec.whatwg.org/#ref-for-dom-xmlhttprequest-open
Created attachment 406946 [details] Patch
Created attachment 406951 [details] Patch
Committed r265963: <https://trac.webkit.org/changeset/265963> All reviewed patches have been landed. Closing bug and clearing flags on attachment 406951 [details].
<rdar://problem/67504479>