9a3434cd17
Convert one error message to use the new facility for testing purposes. The rest of the errors will be improved in follow-on changes. Add tests. Minor comment fixes in dart_api_impl.h. Review URL: http://codereview.chromium.org//8492015 git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@1276 260f80e4-7a28-3924-810f-c04153c831b5