Android execution permissions on Android versions below M?

Recently my ola cabs app after the last update asked for permission to host at runtime. It did not open the location settings screen, but by simply clicking Yes, my device's location (GPS) was turned on and the app continued without going to the location settings or settings screen. This feature was supposed to appear in android M and is only available for MNC preview, so I guess it cannot be used in devices at this point in time. So how does this application implement this feature?