How do I set Google Chrome to close when I swipe away the last tab? On another device, when I swipe away chrome's last open tab, the whole app closes. I don't know how I got it to do that.
On newer Chrome versions, to get the app to close itself when you close tha last tab, setting homepage on is not enough. When you set homepage on, you get to choose between:

Chrome's homepage
(enter custom web adress)

The trick is to select the second option and leave it blank!