Change-Id: I4ba261752750f5087cba810045669512b430b5e0

Unlike on JB, View.setPressed(boolean) is never called when the view
is pressed on ICS. To detect a pressed state of the view, we need to
override View.drawableStateChanged() and check the drawable state
contains state_pressed.

Bug: 8159728
Change-Id: I481051364d6f3d1370742723c3ce19d898ea5463

This is a preliminary implementation because the welcome screen video
is just a placeholder.

Bug: 8159728
Change-Id: I6a2459a266babec2f078fc393b18c77b0b7992a8