UserAgent: Mozilla/5.0 (X11; CrOS x86_64 10452.99.0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/66.0.3359.203 Safari/537.36
Platform: 10452.99.0 (Official Build) stable-channel samus

Steps to reproduce the problem:
I have several extensions with content scripts. They work fine on Chrome-linux and on several pages, but on ChromeOS on youtube.com the content scripts don't load. They are not visible in devtools and the extensions don't work.

One example is:
https://chrome.google.com/webstore/detail/youtube-extension/eldmonccecopkemecmgoceebmckkahjd

Its manifest:
{
  "name": "YouTube extension",
  "version": "0.4",
  "description": "More control over the player",
  "content_scripts": [{
    "js": [ "content.js" ],
    "matches": [
      "https://www.youtube.com/*",
      "https://www.netflix.com/*",
      "https://vimeo.com/*"
    ]
  }],
  "manifest_version": 2
}

What is the expected behavior?
Content script loads and extension works.

What went wrong?
No content script loads and extension doesn't work.

Did this work before? N/A 

Does this work in other browsers? Yes

Chrome version: 66.0.3359.203  Channel: n/a
OS Version: 10452.99.0
Flash Version: