Use WTF::ThreadSafeRefCountedAndCanMakeThreadSafeWeakPtr<> more in WebCore. <rdar://problem/104436726>
Pull request: https://github.com/WebKit/WebKit/pull/8915
Committed 260107@main (8f33f11f2a7f): <https://commits.webkit.org/260107@main> Reviewed commits have been landed. Closing PR #8915 and removing active labels.