Cache the ScrollView platformWidget to avoid [WebAccessibilityObjectWrapper scrollViewParent] hitting the main thread too often.
Created attachment 393402 [details] Patch
Comment on attachment 393402 [details] Patch this looks like it will work. holding onto a NSView off the main thread shouldn't be problematic in and of itself. however, if AppKit makes ax calls on that object outside of WebKit it might require a change in AppKit
Comment on attachment 393402 [details] Patch Clearing flags on attachment: 393402 Committed r258356: <https://trac.webkit.org/changeset/258356>
All reviewed patches have been landed. Closing bug.
<rdar://problem/60386610>