I am very happy to report that I am running the plug-in in the Chromium browser on Ubuntu 16.04.
Chromium 60.0.3112.78 (Developer Build) Built on Ubuntu , running on Ubuntu 16.04 (64-bit)
User Agent Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Ubuntu Chromium/60.0.3112.78 Chrome/60.0.3112.78 Safari/537.36
Command Line /usr/lib/chromium-browser/chromium-browser --enable-pinch --flag-switches-begin --flag-switches-end
Executable Path /usr/lib/chromium-browser/chromium-browser
Profile Path /home/tim/.config/chromium/Default
The plug-in installed without any issues. I was a bit worried about it because some plug-ins actually require Google's Chrome, but this one seems to work out-of-the box on Chromium. I'm not sure if it is the default for Ubuntu now, but at least it was for a while, and some people prefer a browser without the Google branding and extensions (personally I run Chromium because it was the default when I installed Ubuntu).
1Password Version: Not Provided
Extension Version: Not Provided
OS Version: Ubuntu 16.04
Sync Type: Not Provided