add ie9 user.agent with fallback binding to ie8. (in preparation for ie9 support).

Review at http://gwt-code-reviews.appspot.com/1369808


git-svn-id: https://google-web-toolkit.googlecode.com/svn/trunk@9835 8db76d5a-ed1c-0410-87a9-c151d255dfc7
3 files changed