The test at imported/w3c/web-platform-tests/pointerevents/pointerlock/pointerevent_coordinates_when_locked.html is timing out and is currently skipped.
It appears requesting pointer lock does not work when called within a "pointerdown" event handler.
I think the test is buggy, see https://github.com/web-platform-tests/wpt/issues/16406. However, tweaking the test shows failures.
This test assumes that the pointerlockchange event is dispatched synchronously after calling requestPointerLock(). This is the reason it's timing out. It still fails afterwards though, so there is work to do.
Created attachment 372762 [details] Patch
Committed r246753: <https://trac.webkit.org/changeset/246753>
<rdar://problem/52063912>