What browser are you using? I've seen it too. At first I thought it was a new Firefox feature but I've seen it on fennec and the desktop Firefox. I'm thinking its a back end integration with specific sites. Hopefully its not Firefox.
I miss Firefox and prefer it. Something happened to it one day and now I'm unable to use/reinstall Firefox on my computer (see comment history. Could use help with that too...)
So is this my internet life now? If I have to close this popup on pretty much every site I visit I'm definitely going to pull a Ron Swanson throwing the computer in the dumpster scene.
127.0.0.1 id.google.com
127.0.0.1 accounts.google.com
pretty sure that popup is being served from those domains, that might break other things elsewhere, but might be worth a shot just to see what happens