[css-will-change] effect of 'will-change: <shorthand>'

http://dev.w3.org/csswg/css-will-change/#will-change should describe
what happens when the value of the 'will-change' property is a
shorthand.  Presumably it is intended to be the same as specifying
all of the longhand properties that the shorthand sets, but the spec
should say so explicitly.

(Fortunately, 'will-change: all' is explicitly forbidden, so we
don't have to worry about that case.)

-David

-- 
𝄞   L. David Baron                         http://dbaron.org/   𝄂
𝄢   Mozilla                          https://www.mozilla.org/   𝄂
             Before I built a wall I'd ask to know
             What I was walling in or walling out,
             And to whom I was like to give offense.
               - Robert Frost, Mending Wall (1914)