This is the first glimmer of hope for Android music makers in a very long time. Android has always been playing catch-up. Firstly they had the notorious audio latency to contend with. By the time apps like Audio Evolution Mobile got the latency down, iOS was already leagues ahead with all of our inter-app audio and MIDI routing. Today's announcement is a big step towards bringing Google's platform into parity with iOS.
There is even a sample host app available today for developers to test their apps on.