Version 0.3.7.4 Merge revisions 18572, 18615, 18631 and 18633 to trunk. Review URL: https://codereview.chromium.org//12296011 git-svn-id: http://dart.googlecode.com/svn/trunk@18642 260f80e4-7a28-3924-810f-c04153c831b5