The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/04a79336f09692707d9983abfa18f39126cb1a63

commit 04a79336f09692707d9983abfa18f39126cb1a63
Author: Navid Zolghadr <nzolghadr@chromium.org>
Date: Wed May 09 14:55:35 2018

Send boundary events rightaway after pointerup

If pointerup implicitly releases the pointer
capture this change sends the boundary events
rightaway after that without waiting for the
next event.

Bug:  834824 
Change-Id: I538e0b35d1420574f964666aac394c0bde00f4fb
Reviewed-on: https://chromium-review.googlesource.com/1019347
Commit-Queue: Navid Zolghadr <nzolghadr@chromium.org>
Reviewed-by: Dave Tapuska <dtapuska@chromium.org>
Reviewed-by: Mustaq Ahmed <mustaq@chromium.org>
Reviewed-by: Ella Ge <eirage@chromium.org>
Cr-Commit-Position: refs/heads/master@{#557184}
[add] https://crrev.com/04a79336f09692707d9983abfa18f39126cb1a63/third_party/WebKit/LayoutTests/external/wpt/pointerevents/pointerevent_boundary_events_at_implicit_release_hoverable_pointers-manual.html
[add] https://crrev.com/04a79336f09692707d9983abfa18f39126cb1a63/third_party/WebKit/LayoutTests/external/wpt_automation/pointerevents/pointerevent_boundary_events_at_implicit_release_hoverable_pointers-manual-automation.js
[modify] https://crrev.com/04a79336f09692707d9983abfa18f39126cb1a63/third_party/WebKit/LayoutTests/fast/events/pointerevents/mouse-pointer-capture-expected.txt
[modify] https://crrev.com/04a79336f09692707d9983abfa18f39126cb1a63/third_party/blink/renderer/core/input/pointer_event_manager.cc