HP rewrote hpps from HPLIP in 3.8.15 from Python to C.  Now that it's in C, we can integrate it into ChromeOS.  We had believed that we didn't need the filter but there are a number of recently released (in the last year) printers that still use this filter.

If the filter is too large, we'll need to move hplip to a component before this is complete.  That work is covered by https://crbug.com/733069