ApplicationStateTracker::m_isBackground initialization does not account for UIScenes, it merely checks the visibility state of the whole app. It should instead check the visibility state of the window's UIScene.
Created attachment 379245 [details] Patch
Created attachment 379248 [details] Patch
Comment on attachment 379248 [details] Patch r=me
Comment on attachment 379248 [details] Patch Clearing flags on attachment: 379248 Committed r250154: <https://trac.webkit.org/changeset/250154>
All reviewed patches have been landed. Closing bug.
<rdar://problem/55572613>