[giow] (1) <track>.kind: Back off on over-zealous enumming
Fixing https://www.w3.org/Bugs/Public/show_bug.cgi?id=22221
Affected topics: DOM APIs

git-svn-id: http://svn.whatwg.org/webapps@7961 340c8d12-0b0e-0410-8428-c7bf67bfef74

Author:    ianh <ianh@340c8d12-0b0e-0410-8428-c7bf67bfef74>