mobile

I'm considering upgrading from my S2 to the S6 but I'm concerned about situations where, in the past, my S2 was locked up such that the only way to fix it was to pop out the battery.
Trying to power it off through the button didn't work, screen was unresponsive.
With the S6, since you can't just pop the back off and pop the battery out, what would one do in this situation?