The FB/google share buttons on websites totally break MVC. It's just a button but it has cookie & network traffic.

I hate those buttons, people often argue they 'break the web' because of weird privacy/performance side effects, but developers use them because it's convenient to 'drop in' the platform integrations.

By comparison -- integrating an android app with GMS requires modifying a bunch of files (xml layouts, java source, multiple build dependency files). You can't just 'drop it in'.