We don't need ContentChangeObserver since we have a direct pointer with proper hover events. <rdar://problem/49039957>
Created attachment 368264 [details] Patch
Created attachment 368266 [details] Patch
Comment on attachment 368266 [details] Patch Clearing flags on attachment: 368266 Committed r244665: <https://trac.webkit.org/changeset/244665>
All reviewed patches have been landed. Closing bug.