Suspected Malware phishing on Chrome

A window pops up with the chrome-extension://h**************/password-reprompt.html and it asks "Enter your master password to continue for my gmail.com account" It seems like a hacker is on my computer. I can get rid of the window by turning my computer off and then back on! It eventually pops back up. Malewarebytes doesn't detect it. Google doesn't detect it either. How can I find out if I've been hacked?

[Edited by Moderator]