That would require a lot of work. There are parts, at least, of the Nik collection that use deep hooks into Photoshop; it's not just a set of typical 8BA/8BF "give me a pointer to a TIFF I can play with" plugins.
This didn't happen in the last years. I doubt it will happen at all. I think they're more interested in the algorithms to reuse them in Google Apps the one or the other way.