Dude GoogleAuth is pure nonsense magic. On one line you get your auth-instance from gapi.auth2.init..
But then you render the auth-button with a static method aka gapi.signin2.render (which has some kind of success and error handlers, but don't worry, they fire randomly, they won't help you debug this api mess)
SOME-FUCKING-HOW this static signin2.rendershit knows of your auth2 instance and it works. But actually it makes no sense and is just a big mess of api-calls. Google, get your shit together, this ain't pretty.

Oh and forget your informative console.log.. this shit will get erased everytime you try something because of "Navigated to https://accounts.google.com/o/...". why ever the fuck this clears the console even tho it doesn't affect the top window. So preserve that fucking log and drown in a mass of bullshit.

In the end, as it is with everything, it somehow works. But FFS that's some weird api design Google has going on..