Roll Observatory packages and add a roll script

packages/charted/lib/charts/cartesian_renderers/bubble_chart_renderer.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.charts;
 
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   }
 
   void _event(StreamController controller, data, int index, Element e) {
     if (controller == null) return;
     var rowStr = e.parent.dataset['row'];
     var row = rowStr != null ? int.parse(rowStr) : null;
     controller.add(
         new DefaultChartEventImpl(_scope.event, area, series, row, index, data));
   }
 }