Instead of using the raw uint64_t type to represent callbacks, use the purpose built WebKit::CallbackID type.
<rdar://problem/61791784>
Created attachment 396567 [details] Patch
Comment on attachment 396567 [details] Patch r=me (mac-wk2 is orange, so I didn't mark cq+)
It looks like Mac-wk2 is in some horrible state. Every patch I look at claims it is broken.
I confirmed that the test results are the same with or without the patch locally.
Created attachment 396727 [details] Patch for landing
Committed r260231: <https://trac.webkit.org/changeset/260231> All reviewed patches have been landed. Closing bug and clearing flags on attachment 396727 [details].