How to suppress system bars on Android?

I can’t submit my app to the Daydream store because “the app does not suppress system bars.” I’ve looked everywhere and can’t find anything that explains how to do this within Unity. I have “Virtual Reality supported” checked which should disable the notification and navigation bars automatically, and I haven’t found anything else I can add to the AndroidManifest.xml file to keep everything full screen.

Shouldn’t Unity be hiding the system bars automatically? Is there anything else I can put in the manifest or code to ensure the app remains full screen?

I’m using Unity 5.6.0b9 with no splash screen.

FYI
It reproduced and will be fixed by Unity.

https://forum.unity3d.com/threads/daydream-bug-causing-google-play-rejection-the-app-does-not-suppress-system-bars.457605/