ffbfc2ce17
First cut at an AST visitor that collects refinable types (with a fix to the type analyzer to flag inferred type nodes). Review URL: https://chromiumcodereview.appspot.com//10512012 git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@8307 260f80e4-7a28-3924-810f-c04153c831b5