A known leaker and SteamVR data miner named Bradley Lynch reports that Valve is working on an Android emulator. Lynch has spotted five apps in a package on SteamDB, with two of them displaying new artwork that references Waydroid, an open-source and free Android emulator.
Hmm something about this has me fantasizing about a phone sized deck. But considering Valves development of VR and this development, I think they are going to tap into the android based VR dev pool for porting titles to an official Android on Steam platform.