There is an extension called Keep Awake in the Chrome Web Store. I was reading an article in the Chomium forum about it. It allows you to toggle the power setting on/off. The other way is good until reboot. Here are the steps I found.
Login with the admin user.
Open a terminal by hiting CTRL+ALT+T
Type the following
shell (to drop into a standard bash shell)
sudo stop powerm - to disable sleep when lid is closed. You could go with the longer version of: sudo initctl stop powerm but there is no reason to type more…
sudo stop powerd - to disable all other power management features.
Now logout from the menu – But do not restart!