Signing in with redirect prevent events to be fired

[masonlouchart]

When the element use redirect, it's re-initialized on the authentication callback. So events are not always fired and the user can't continue its login process.

This issue should be solved at the same time of the #31 but I wanted to notify it.

[masonlouchart]

OK guys, I confirm my thought.

The redirect cuts the flux of the signing-in process so the event signedin is never thrown.

Moreover, the firebase-auth element get the last snapshot of the user when it client API is ready. Because this snapshot is a connected user, the property user of login-fire elements changes.

Maybe the right moment to fire the signedin (and signedout) event(s) is when the user has actually be updated by firebase-auth. After all, we want fire an event when the property user changed right? So why not simply observe these changes...

NB: I'm using the v1.1.0 so I guess this issue is not related to Polymer v1 only

[masonlouchart]

It's working with Polymer 2 when the user allow the domain that authenticate him to use cookies. I guess the issue with Polymer 1 has the same origin.

Ref #91