d700bba3e4
Some tags don't have their own HTMLElement subclass (because they lack unique DOM properties), but it should still be possible to extend them. R=blois@google.com Review URL: https://codereview.chromium.org//90113002 git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@30833 260f80e4-7a28-3924-810f-c04153c831b5