Was able to reproduce it also in Canary 69.0.3445.0

Able to reproduce the issue on reported chrome version 66.0.3359.181 & latest stable 67.0.3396.62  and on latest chrome 69.0.3446.0 using ,Windows 10, Mac 10.13.1 and ubuntu 14.04. 
 
Same behavior is seen on M60(60.0.3112.113) hence considering it as non-regression and marking it as Untriaged.


Thanks! 

Looks like an issue with skia's gpu-accelerated path rendering.

I wasn't able to repro this on my devices (Ubuntu, Win, Mac). It also didn't seem to be using the tessellating path renderers. Perhaps it's an oval-drawing issue?

Handing over to Brian for further triage.

Here is another example https://marci4.github.io/chromecanvasgpuvscpu/canvasgpuvscpucirclee.html 

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	CPU.PNG 2.8 KB View Download

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	GPU.PNG 2.5 KB View Download

The following revision refers to this bug:
  https://skia.googlesource.com/skia/+/3ac1f959878418828044a5ebbaa42d1298940d0b

commit 3ac1f959878418828044a5ebbaa42d1298940d0b
Author: Brian Salomon <bsalomon@google.com>
Date: Fri Sep 07 20:21:24 2018

Preseve tangents when converting cubics->quads in GrAAHairlinePathRenderer

Bug:  chromium:847759 
Change-Id: I35a6d069f732d906714a640fca59a71fd35b74ec
Reviewed-on: https://skia-review.googlesource.com/152664
Commit-Queue: Brian Salomon <bsalomon@google.com>
Reviewed-by: Greg Daniel <egdaniel@google.com>

[modify] https://crrev.com/3ac1f959878418828044a5ebbaa42d1298940d0b/gn/gm.gni
[add] https://crrev.com/3ac1f959878418828044a5ebbaa42d1298940d0b/gm/crbug_847759.cpp
[modify] https://crrev.com/3ac1f959878418828044a5ebbaa42d1298940d0b/src/gpu/GrPathUtils.h
[modify] https://crrev.com/3ac1f959878418828044a5ebbaa42d1298940d0b/src/gpu/GrPathUtils.cpp

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/d5e69f489d9728630b34a155d5193fea99c25ac2

commit d5e69f489d9728630b34a155d5193fea99c25ac2
Author: skia-chromium-autoroll <skia-chromium-autoroll@skia-buildbots.google.com.iam.gserviceaccount.com>
Date: Fri Sep 07 23:23:32 2018

Roll src/third_party/skia 24de64834600..24e8f58cfa9c (11 commits)

https://skia.googlesource.com/skia.git/+log/24de64834600..24e8f58cfa9c


git log 24de64834600..24e8f58cfa9c --date=short --no-merges --format='%ad %ae %s'
2018-09-07 swiftshader-skia-autoroll@skia-buildbots.google.com.iam.gserviceaccount.com Roll third_party/externals/swiftshader a062f321768d..3655209d86f4 (1 commits)
2018-09-07 reed@google.com Revert "Revert "add flag to soften the blow of removing a legacy api for flutter""
2018-09-07 bsalomon@google.com Preseve tangents when converting cubics->quads in GrAAHairlinePathRenderer
2018-09-07 borenet@google.com [infra] Revert broken recipe rolls, add test for missing patch_ref
2018-09-07 brianosman@google.com Add support for gray + colorspace to SkCodec
2018-09-07 bungeman@google.com Simplify FreeType glyph bounds.
2018-09-07 caryclark@google.com reland fix picture subclass destructor doc
2018-09-07 mtklein@google.com add clamp_gamut
2018-09-07 jvanverth@google.com Revert "add flag to soften the blow of removing a legacy api for flutter"
2018-09-07 borenet@google.com Add new autoroll service accounts to AUTHORS check bypass
2018-09-07 mtklein@google.com remove -k 0 from builds


Created with:
  gclient setdep -r src/third_party/skia@24e8f58cfa9c

The AutoRoll server is located here: https://autoroll.skia.org/r/skia-autoroll

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+/master/autoroll/README.md

If the roll is causing failures, please contact the current sheriff, who should
be CC'd on the roll, and stop the roller if necessary.

CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_trusty_blink_rel;luci.chromium.try:android_optional_gpu_tests_rel;luci.chromium.try:linux_optional_gpu_tests_rel;luci.chromium.try:mac_optional_gpu_tests_rel;luci.chromium.try:win_optional_gpu_tests_rel

BUG= chromium:847759 
TBR=jvanverth@chromium.org

Change-Id: I5346f6bf867e5501abfe07bf4f1a78db070605b9
Reviewed-on: https://chromium-review.googlesource.com/1213446
Reviewed-by: skia-chromium-autoroll <skia-chromium-autoroll@skia-buildbots.google.com.iam.gserviceaccount.com>
Commit-Queue: skia-chromium-autoroll <skia-chromium-autoroll@skia-buildbots.google.com.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/master@{#589716}
[modify] https://crrev.com/d5e69f489d9728630b34a155d5193fea99c25ac2/DEPS