I've reset the chrome://flags to their default and restarted the browser too.

Unable to reproduce the issue on chrome reported version# 67.0.3396.87 using Ubuntu 14.04 with steps mentioned below:
1) Launched chrome reported version, right click on windows and selected 'Inspect' from context menu
2) Able to see Devtools opened

@Reporter: Please find the attached screencast for your reference, if possible try to test this issue by creating new person with no apps and extensions in it or try to test this issue on latest chrome stable and let us know if the issue still persists.
You can download latest chrome stable from URL: https://www.chromium.org/getting-involved/dev-channel.

Thanks!
 

Deleted: 863778.ogv 4.7 MB

	863778.ogv 4.7 MB View Download

Created a new profile without any extensions, but the issue still remains. Created a video to show the bug in action.

Deleted: bug.mkv 1.1 MB

bug.mkv 1.1 MB 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

These are the USE flags that Chromium was built with:

www-client/chromium-67.0.3396.87::gentoo was built with the following:
USE="(pic) suid -component-build -cups -custom-cflags -gnome-keyring -hangouts -jumbo-build -kerberos (-neon) -proprietary-codecs -pulseaudio (-selinux) (-system-ffmpeg) (-system-icu) (-system-libvpx) (-tcmalloc) -widevine" L10N="am ar bg bn ca cs da de el en-GB es es-419 et fa fi fil fr gu he hi hr hu id it ja kn ko lt lv ml mr ms nb nl pl pt-BR pt-PT ro ru sk sl sr sv sw ta te th tr uk vi zh-CN zh-TW"

And this is what's being displayed in the terminal when Chromium is launched from it:

[9746:9746:0717/153316.523988:ERROR:CONSOLE(3571)] "Uncaught SyntaxError: Unexpected identifier", source: chrome-devtools://devtools/bundled/shell.js (3571)
[9746:9746:0717/153316.537828:ERROR:CONSOLE(1)] "Uncaught ReferenceError: allDescriptors is not defined", source: chrome-devtools://devtools/bundled/devtools_app.js (1)
[9746:9746:0717/153316.538006:ERROR:CONSOLE(14)] "Uncaught ReferenceError: Runtime is not defined", source: chrome-devtools://devtools/bundled/devtools_app.html?remoteBase=https://chrome-devtools-frontend.appspot.com/serve_file/@878cd31214ac27a3996927cd5c9c138b10c9fc8d/&can_dock=true&dockSide=undocked&experiments=true (14)
[9746:9746:0717/153316.539758:ERROR:CONSOLE(57)] "Uncaught TypeError: Cannot read property 'setInspectedTabId' of undefined", source: chrome-devtools://devtools/bundled/devtools_compatibility.js (57)

Unable to reproduce the issue on latest chrome stable# 69.0.3497.100 and on chromium build# 69.0.3497.0 with steps mentioned in comment# 3.

@Reporter: Could you please try to test this issue on latest chrome stable with no apps and extensions in it and let us know if the issue still persists. You can download latest chrome stable from the URL: https://www.chromium.org/getting-involved/dev-channel.

Thanks!

**UI mass Triage**

We were unable to reproduce this bug. If this bug still reproduces for you,please reopen or file a new issue.

Thanks!