[css3-background] computed value of 'border-width'

The computed value of 'border-width' in
http://www.w3.org/TR/2005/WD-css3-background-20050216/#the-border-width
needs to be updated to match
http://www.w3.org/TR/CSS21/box.html#border-width-properties which
says:

  absolute length; '0' if the border style is 'none' or 'hidden' 

(It should also probably be specified explicitly whether the
computed value of 'border-width' should be affected by width values
in 'border-image', whether or not it is.)

-David

-- 
L. David Baron                                 http://dbaron.org/
Mozilla Corporation                       http://www.mozilla.com/