The intent-to-remove was approved.

https://groups.google.com/a/chromium.org/forum/#!topic/blink-dev/VlbJIDOIIqw

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/b497f749f667199fc86edee499bdb36519fa4407

commit b497f749f667199fc86edee499bdb36519fa4407
Author: tkent <tkent@chromium.org>
Date: Tue Apr 18 03:23:10 2017

Remove non-standard document.createEvent('WebKitAnimationEvent').

Intent-to-remove:
https://groups.google.com/a/chromium.org/forum/#!topic/blink-dev/VlbJIDOIIqw

BUG= 711601 
TBR=haraken@chromium.org

Review-Url: https://codereview.chromium.org/2821863002
Cr-Commit-Position: refs/heads/master@{#465125}

[modify] https://crrev.com/b497f749f667199fc86edee499bdb36519fa4407/third_party/WebKit/LayoutTests/external/wpt/dom/nodes/Document-createEvent-expected.txt
[modify] https://crrev.com/b497f749f667199fc86edee499bdb36519fa4407/third_party/WebKit/LayoutTests/fast/events/event-creation-expected.txt
[modify] https://crrev.com/b497f749f667199fc86edee499bdb36519fa4407/third_party/WebKit/LayoutTests/fast/events/event-creation.html
[modify] https://crrev.com/b497f749f667199fc86edee499bdb36519fa4407/third_party/WebKit/Source/build/scripts/make_event_factory.py
[modify] https://crrev.com/b497f749f667199fc86edee499bdb36519fa4407/third_party/WebKit/Source/core/frame/UseCounter.h
[modify] https://crrev.com/b497f749f667199fc86edee499bdb36519fa4407/tools/metrics/histograms/histograms.xml