Share more code between FormAssociatedElement and HTMLImageElement.
Pull request: https://github.com/WebKit/WebKit/pull/6503
Committed 256697@main (5780eeea65cd): <https://commits.webkit.org/256697@main> Reviewed commits have been landed. Closing PR #6503 and removing active labels.
<rdar://problem/102369636>
Re-opening for pull request https://github.com/WebKit/WebKit/pull/6541
Committed 256723@main (ef6010c748c3): <https://commits.webkit.org/256723@main> Reviewed commits have been landed. Closing PR #6541 and removing active labels.