This is only possible via user interaction so we need to synthesize a user gesture indicator. This is done properly in the WK1/DRT case, but not in the WK2 case.
<rdar://problem/38388641>
Created attachment 335722 [details] Patch
Comment on attachment 335722 [details] Patch Clearing flags on attachment: 335722 Committed r229588: <https://trac.webkit.org/changeset/229588>
All reviewed patches have been landed. Closing bug.