Use CheckedLock more in WTF to benefit from Clang Thread Safety Analysis.
Created attachment 429225 [details] Patch
Created attachment 429227 [details] Patch
Created attachment 429228 [details] Patch
Committed r277847 (237989@main): <https://commits.webkit.org/237989@main> All reviewed patches have been landed. Closing bug and clearing flags on attachment 429228 [details].
<rdar://problem/78290307>