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.