[giow] (1) Once you close a BroadcastChannel, you can't use it to send anymore either
Fixing https://www.w3.org/Bugs/Public/show_bug.cgi?id=26545
Affected topics: DOM APIs

git-svn-id: http://svn.whatwg.org/webapps@8762 340c8d12-0b0e-0410-8428-c7bf67bfef74