Remove ProcessPendingPointerCaptureForPointerLock

We already moved the PointerEvent creation for pointerlock to PEM, so
the update pending capture can be done within the event dispatching and
avoid creating an extra PE for pointer capture events.

Test=wpt/.../pointerevent_pointerlock_after_pointercapture-manual.html

Bug: 802067
Change-Id: I7ed5396eb9814c3ea3ba6c692d3c6ec137a30d8b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1617138
Reviewed-by: Navid Zolghadr <nzolghadr@chromium.org>
Reviewed-by: David Bokan <bokan@chromium.org>
Commit-Queue: Ella Ge <eirage@chromium.org>
Cr-Commit-Position: refs/heads/master@{#661941}