Disabling test for null on getBrowserById for DOM elements without DTD when running on Chrome 11 and beyond

Review at http://gwt-code-reviews.appspot.com/1462805


git-svn-id: https://google-web-toolkit.googlecode.com/svn/trunk@10354 8db76d5a-ed1c-0410-87a9-c151d255dfc7