Fix the ENABLE(OVERLAY_REGIONS_IN_EVENT_REGION) build
<rdar://problem/102056220>
Pull request: https://github.com/WebKit/WebKit/pull/6219
Committed 256425@main (bbfd4c72af3f): <https://commits.webkit.org/256425@main> Reviewed commits have been landed. Closing PR #6219 and removing active labels.