Unless I'm mistaken, this is the way that Android already works. If you plug in a locked phone, you must unlock it to get any USB data connection to the phone. When a phone with a data connection is unplugged, the permissions immediately reset and you have to unlock the phone again to restart a data connection.

Not only that, on my Nexus 5x, I have to manually switch from charging mode to data transfer mode every time (the setting doesn't stick).

Unless I've misunderstood the significance of this change, Android actually provides much more security since you can't download files off a locked phone, not even within 7 days.