update elements and fix some bugs

lib/src/google-chart/google-chart.html

 <link rel="import" href="../polymer/polymer.html">
 <link rel="import" href="../iron-ajax/iron-ajax.html">
 <link rel="import" href="../google-apis/google-legacy-loader.html">
 
 <!--
 `google-chart` encapsulates Google Charts as a web component, allowing you to easily visualize
 data. From simple line charts to complex hierarchical tree maps, the chart element provides a
 number of ready-to-use chart types.
 
     <google-chart
@@ skipping 58 matching lines @@
      * @param {object} detail
      *   @param {array} detail.selection The user-defined selection.
      */
 
     properties: {
       /**
        * Sets the type of the chart.
        *
        * Should be one of:
        * - `area`, `bar`, `bubble`, `candlestick`, `column`, `combo`, `geo`,
-       *   `histogram`, `line`, `pie`, `scatter`, `stepped-area`
+       *   `histogram`, `line`, `pie`, `scatter`, `stepped-area`, `treemap`
        *
        * See <a href="https://google-developers.appspot.com/chart/interactive/docs/gallery">Google Visualization API reference (Chart Gallery)</a> for details.
        *
        */
       type: {
         type: String,
         value: 'column',
         observer: '_typeChanged'
       },
 
@@ skipping 200 matching lines @@
         'candlestick': google.visualization.CandlestickChart,
         'column': google.visualization.ColumnChart,
         'combo': google.visualization.ComboChart,
         'geo': google.visualization.GeoChart,
         'histogram': google.visualization.Histogram,
         'line': google.visualization.LineChart,
         'pie': google.visualization.PieChart,
         'scatter': google.visualization.ScatterChart,
         'stepped-area': google.visualization.SteppedAreaChart,
         'table': google.visualization.Table,
-        'gauge': google.visualization.Gauge
+        'gauge': google.visualization.Gauge,
+        'treemap': google.visualization.TreeMap
       };
     },
 
     _loadPackageByChartType: function() {
       this._packages = {
         'area': 'corechart',
         'bar': 'corechart',
         'bubble': 'corechart',
         'candlestick': 'corechart',
         'column': 'corechart',
         'combo': 'corechart',
         'geo': 'corechart',
         'histogram': 'corechart',
         'line': 'corechart',
         'pie': 'corechart',
         'scatter': 'corechart',
         'stepped-area': 'corechart',
         'table': 'table',
-        'gauge': 'gauge'
+        'gauge': 'gauge',
+        'treemap': 'treemap'
       };
     },
 
     _loadData: function() {
       this._canDraw = false;
       if (this._isReady) {
         if (typeof this.data == 'string' || this.data instanceof String) {
           // Load data asynchronously, from external URL.
           this.$.ajax.generateRequest();
         } else {
@@ skipping 47 matching lines @@
         } else if (data.length > 0) {
           dataTable = google.visualization.arrayToDataTable(data);
         }
       }
 
       return dataTable;
     }
   });
 })();
 </script>