Able to reproduce the issue on reported chrome version #70.0.3538.102 and latest chrome #70.0.3617,0 using Mac OS 10.12.6 by following steps as per comment#0.The following is the bisect information.
Note: Issue is not seen on Windows and Linux

Bisect Information:
================
Good build: 70.0.3503.0
Bad build: 70.0.3504.0
Change Log: https://chromium.googlesource.com/chromium/src/+log/da08e1808cb0835dd647407869b84e6f30a745d0..5731cb95b0f45cd81e95415d67ba7ec77ade61d7
Note:Unable to provide per-revision as we are getting error "[Errno 2] No such file or directory".Hence providing chromium bisect information. 

As we could not find the correct suspect from the changelog, tentatively marking it as untriaged and requesting someone from Platform>Devtools team to help us in assigning the issue to correct owner.
Adding Release Block Stable as it seems to be a recent regression. Please feel free to remove it if not applicable.

Thanks.!

As this is regressed in M7, not a blocker for M71. Pls target fix for M72.

+dgozman@ & pfeldman@, DevTools Eng.

This issue is marked as a release blocker with no milestone associated. Please add an appropriate milestone.

All release blocking issues should have milestones associated to it, so that the issue can tracked and the fixes can be pushed promptly.

Thanks for your time! To disable nags, add the Disable-Nags label.

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

This issue is marked as a release blocker with no milestone associated. Please add an appropriate milestone.

All release blocking issues should have milestones associated to it, so that the issue can tracked and the fixes can be pushed promptly.

Thanks for your time! To disable nags, add the Disable-Nags label.

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

[bulk update] Just a heads up, M72 stable is about 2 weeks away. This issue is marked as RB-Stable. Please take a look.