Reporter@ Thanks for the issue.

Tested this issue on Windows 10 on the reported version 66.0.3359.33 and the latest Canary 67.0.3377.0 by following the below steps.
 
1. Launched Chrome and opened Devtools.
2. Navigated to settings and Enabled CSS source maps and disabled Preserve log checkbox.
3. Clicked on Network tab and hit the record button.
4. Clicked on Sources tab and blackboxed a js file.
5. Refreshed the page and can see no error logged into the console and no crashes observed.
Attached is the screen cast for reference.

Request you to check and confirm if these are the right steps in reproducing the issue, which will help in further triaging.

Also request you to provide the screen cast of the steps followed to reproduce the issue.

Thanks..

Deleted: 823722.mp4 2.0 MB

	823722.mp4 2.0 MB View Download

Are you sure there is a source map on that page?

I'll search for a public site where I can reproduce so that it is easier to follow the steps, but in the meantime I have a screencast showing the steps I take to reproduce.

Deleted: devtoolserror.mp4 696 KB

	devtoolserror.mp4 696 KB View Download

Thank you for providing more feedback. Adding the requester to the cc list.

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

Just realised it isn't clear in the video, but I hit F5 on the left dev tools at the 11 seconds mark.

Alright, managed to find a public website on which I can (partially) reproduce. I get the same error in the dev tools on dev tools, but frustratingly the console does clear on refresh, which it doesn't on my internal reproduction case...

Any pointers on how I could figure out the difference between these two situations?


Partial reproduction steps:
1. Go to http://getbootstrap.com/
2. Open the dev tools
3. Check settings (JS source map enabled)
4. Open the dist/js/bootstrap.min.js
5. Open dev tools on dev tools
6. Reload the website

I've noticed now that depending on when you blackbox it, you get different errors.

If you already had the script blackboxed from the beginning (as I had in the bootstrapconsoleerror video because I forgot to remove the rule and in normal situations because you're working on a project and the rules had already been set up), you get the "Cannot read property 'removeSourceMap' of undefined" error.

If you blackbox it at step 4 (right click script, click blackbox script), nothing will happen at the first reload. But if you refresh a second time, it will throw a "Cannot read property 'count' of undefined" error. This is shown in the followupblackboxing video.

Deleted: bootstrapconsoleerror.mp4 3.0 MB

	bootstrapconsoleerror.mp4 3.0 MB View Download

Deleted: followupblackboxing.mp4 706 KB

	followupblackboxing.mp4 706 KB View Download

pot@ Thanks for the feedback.

Able to reproduce this issue on Mac 10.12.6, Windows 10 and Ubuntu 14.04 on the latest Canary 67.0.3378.0 and Beta 66.0.3359.45 as per comment #7.

Bisect Information:
===================
Good Build: 66.0.3328.0 
Bad Build : 66.0.3329.0 

On executing the per-revision bisect script, below is the Changelog URL:

https://chromium.googlesource.com/chromium/src/+log/3511e3b146f4f024c292fb2003b9e7315365a11d..6d47d4076e434c6b26e783563edd2ab48533e731

From the above Changelog, suspecting the below change:
Reviewed-on:  https://chromium-review.googlesource.com/875419

lushnikov@ Please check and confirm if this issue is related to your change, else help us in assigning to the right owner.

Adding ReleaseBlock-Stable for M-66 as this is a recent regression. Please feel free to remove it if it is not applicable.

Thanks.

Friendly ping to get an update on this issue as it is marked as stable blocker for M66.

Thanks..!

Just a heads up, M66 Stable cut is on April 12th, 10 days away. This issue is marked as RB-Stable for 66. Please make sure to address this issue prior to stable cut. Thanks! 

Gentle ping to get an update on this issue as it is marked as stable blocker & M66 Stable cut is on April 12th.

Thanks..! 

Reminder: Please note that M66 Stable is only 7 days away. This bug has been marked as ReleaseBlock Stable for M66. So please take a look and appropriately address this bug. 

I think you don't need to block the stable release on it since it only affects developers, who tend to be on beta or canary anyway. But that's just my thoughts as an outsider with limited knowledge of your procedures and all.

Works fine for me on 73.0.3644.0