How to stream audio from PC to android device through USB?
What you just read from the Android developer's guide is actually a specification for an Android device to send, not receive, audio using USB to an external device, such as a charging dock-cum-music player. This is a host mode USB connection. This does not allow your pc to send ( stream) audio to your device via USB. However, if your PC has Bluetooth, maybe you can register your phone as a Bluetooth audio player and stream audio to it that way.