[e] (0) Move stroking requirements into the stroking algorithm
Fixing https://www.w3.org/Bugs/Public/show_bug.cgi?id=23917
Affected topics: Canvas

git-svn-id: http://svn.whatwg.org/webapps@8399 340c8d12-0b0e-0410-8428-c7bf67bfef74