[ac] (0) Restrict <main> from having <aside>, <footer>, <header>, or <nav> ancestors
Fixing https://www.w3.org/Bugs/Public/show_bug.cgi?id=21553
Affected topics: HTML

git-svn-id: http://svn.whatwg.org/webapps@7817 340c8d12-0b0e-0410-8428-c7bf67bfef74
(cherry picked from commit ea409172f294ae18432bbc208552deb03d156d93)
[e] (0) Fix example.
Fixing https://www.w3.org/Bugs/Public/show_bug.cgi?id=18702
Affected topics: DOM APIs

git-svn-id: http://svn.whatwg.org/webapps@7818 340c8d12-0b0e-0410-8428-c7bf67bfef74
(cherry picked from commit 9482527c51351de821a1cf5ba8bb010b551f7218)

Fix postMessage example.