Do we know for sure that Blink itself needs to support PNaCL / Pepper? Or is it possible that PNaCL and Pepper can be implemented on top of Blink? Do we know

Do we know for sure that Blink itself needs to support PNaCL / Pepper? Or is it possible that PNaCL and Pepper can be implemented on top of Blink? Do we know for sure that Blink itself is violating any of these principles, to merely expose PNaCL / Pepper in Chrome?