Roll Observatory packages and add a roll script

packages/charted/lib/core/utils/object_factory.dart

 //
 // Copyright 2014 Google Inc. All rights reserved.
 //
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file or at
 // https://developers.google.com/open-source/licenses/bsd
 //
 
 part of charted.core.utils;
 
@@ skipping 20 matching lines @@
       throw new ArgumentError('Element $name not found in ComponentFactory');
     }
     var creator = _components[name],
         instance = creator();
     if (instance == null) {
       throw new ArgumentError('Component $name initialization failed.');
     }
     return instance;
   }
 }