First, if you saved passwords, change those passwords now.
Nest read https://support.google.com/accounts/answer/6160500?hl=en
"Remotely ring, lock, or erase a lost device" Looks like what you want.
I have a Samsung Galaxy j3 (2016). I live in the UK. I have saved a few passwords in my Bookmarks, and I now realise that if my phone was lost or stolen, my details would be shown. Can you please tell me how to cancel these passwords. My browser is Google Chrome.