Roll Observatory packages and add a roll script

packages/intl/lib/src/http_request_data_reader.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 /**
  * This contains a reader that accesses data using the HttpRequest
  * facility, and thus works only in the web browser.
  */
 
 library http_request_data_reader;
@@ skipping 34 matching lines @@
         completer.completeError(e);
       }
     });
 
     xhr.onError.listen(completer.completeError);
     xhr.send();
 
     return completer.future;
   }
 }