Why Is My Browser Diverting to a Porn Site or a 'Virus Detected' Pop up When I Browse the Internet on Chrome?

I have a Nexus 5 running Kit Kat 4.4.4. Whenever I'm browsing on Chrome, I will get redirected to a porn site or a pop up will 'pop up' which says I have a virus and the only only button I can press is "OKAY" which redirects me to a site that says is scanning my phone...

I decided to reset to factory settings and changed all my account passwords, but the redirecting in Chrome remains. All apps I have downloaded from the Play Store. The problem started when I downloaded the GrooveShark app. I have since deleted that app and reset factory settings and still I get the same problem.

I have run multiple anti virus apps and none of them report a virus. Please help?