We'll use these accessors to make sure that the notificationclick and notificationclose events are routed to the right data store.
<rdar://problem/105287995>
Pull request: https://github.com/WebKit/WebKit/pull/9945
Committed 260379@main (f8d4e263f3a9): <https://commits.webkit.org/260379@main> Reviewed commits have been landed. Closing PR #9945 and removing active labels.