PositionError Requests

Hello --

I'd like to request an error code 5, UNKNOWN. There are certain errors  
that may occur that are not covered by any of the error codes listed.  
Generally these can be when the native implementation can't determine  
the correct things about the JS code given. You can search for  
UNKNOWN_ERROR in the last patch to https://bugs.webkit.org/show_bug.cgi?id=21475 
  for some examples.

I'd also like to request that the errors have names, such as suggested  
by Olli Pettay on October 15 on this email list.

Thanks,
-- Greg