Make SurfaceView rendering generic in SysUI

WindowlessWindowManager is not visible as external APIs, so for
launcher / wallpaper to use the API the rendering code has to be in the
SysUI.

Bug: 150224413
Test: Manual. Make sure universal smartspace still works as intended.
Change-Id: If006d622f181f6c8cc7c1cebda3f63b0b2ad85d5