Norton Pop-up Alert, ref Google chrome extensions

I kept getting a Norton alert pop-up, on start-up, saying I needed to download "Google chrome extensions" for safety on the internet.

I have downloaded it, but now wonder if it really was from Norton, as I now think it should have come through live updates.

I have since reinstalled Norton and the pop-up no longer appears. Full scan has not shown anything wrong so  am I safe ?

 Ollybean