[giow] (3) Changes to a CSS style sheet take effect immediately
Fixing https://www.w3.org/Bugs/Public/show_bug.cgi?id=26971
Affected topics: HTML

git-svn-id: https://svn.whatwg.org/webapps@8838 340c8d12-0b0e-0410-8428-c7bf67bfef74