Auto Shutdown (WebExtension) от Sarah Av., Andy Portmen

Auto Shutdown extension executes a custom OS level command when all downloading jobs are finished. This extension can be used to turn off computer, hibernate it, or even run a custom command like playing a music song using a desktop application!

For this extension to work, a native messaging application needs to be installed. For more info please visit
http://add0n.com/auto-shutdown.html

To report bugs use:
https://github.com/andy-portmen/auto-shutdown