Import WPT tests for blocked modal dialogs in sanboxed documents
Created attachment 335596 [details] Patch
This patch imports https://github.com/w3c/web-platform-tests/commit/3c5d8637bb57dedaaf2995b56e60502b9e85e516
Committed r229535: <https://trac.webkit.org/changeset/229535>
<rdar://problem/38397897>