We have a number of classes which implement `_addToLog`, we should share code instead of re-implementing the function.
<rdar://problem/91383969>
Pull request: https://github.com/WebKit/WebKit/pull/253
Committed r292536 (249374@main): <https://commits.webkit.org/249374@main> Reviewed commits have been landed. Closing #253 and removing active labels.