pathLength="" affecting stroke dashing

There was an issue in the Painting chapter to describe how the
pathLength="" attribute affects stroke dashing.  I’ve fixed that in the
spec, but upon testing I found that implementations differ.  Firefox
(and old Presto Opera) do scale stroke-dasharray and stroke-dashoffset
by the factor that results from pathLength="", while WebKit/Blink/Edge
don’t.  I think it does make sense for pathLength="" to affect these, as
anything that is specified relative to the length of the path should.

I made an example that uses pathLength="" and dashing, which obviously
looks “correct” in Firefox and not in other browsers:

https://github.com/w3c/svgwg/blob/master/master/images/painting/dash-pathlength.svg

Is this something that WebKit/Blink/Edge would be willing to fix?

-- 
Cameron McCormack ≝ http://mcc.id.au/