LineCandidate.inlineContent is the candidate content for the line and when the line breaker says revert (move back to an earlier position on the line) this candidate content is simply not part of the line at all and should be ignored.
Created attachment 426447 [details] Patch
<rdar://76760857>
Created attachment 426456 [details] Patch
Committed r276269 (236751@main): <https://commits.webkit.org/236751@main> All reviewed patches have been landed. Closing bug and clearing flags on attachment 426456 [details].