How to check if browser supports extensions?

I have written a chrome extension for my website, but discovered that extensions do not work on mobile browsers for chrome. Right now, the website checks if the user has the extension installed. If the user doesn’t, the website asks the user to install the extension via inline install.

The issue is that I don’t want to prompt a user to install an extension if they are running chrome on a mobile devise because it won’t work. I would like to add a check for the ability of a browser to run extensions instead of user agent sniffing for mobile devise. Modernizr doesn’t seem to have a check for this. Any ideas?