0.4.6.0
Update trunk to version 0.4.6.0
svn merge -r 20992:21363 https://dart.googlecode.com/svn/branches/bleeding_edge trunk

git-svn-id: http://dart.googlecode.com/svn/trunk@21377 260f80e4-7a28-3924-810f-c04153c831b5