If this is true, it's insane that this would work:
- why does CWS respond to cross-site requests?
- why is chrome sending the credentials (or equivalent) in these requests?
- why is the button enabled server-side and not via JS? Google must be confident in knowing the exact and latest state of your installed extensions enough to store it on their servers, I guess
It's not true. The person you're responding to has a habit of posting implausible-but-plausibly-plausible nonsense, and it's not how this works at all.