Update charted to 0.4.8 and roll

packages/charted/lib/charts/behaviors/chart_tooltip.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;
 
@@ skipping 73 matching lines @@
       }
       _tooltipRoot.append('div')
         ..classed('tooltip-total')
         ..text((formatter != null) ? formatter(total) : total.toString());
     }
 
     // Find the currently selectedMeasures and hoveredMeasures and show
     // tooltip for them, if none is selected/hovered, show all.
     var activeMeasures = [];
     if (showSelectedMeasure) {
-      if(_state != null) {
+      if (_state != null) {
         activeMeasures.addAll(_state.selection);
-        activeMeasures
-            .add(_state.preview != null
-                ? _state.preview
-                : _state.hovered.first);
+        activeMeasures.add(
+            _state.preview != null ? _state.preview : _state.hovered.first);
       } else {
-
         // If state is null, chart tooltip will not capture selection, but only
         // display for the currently hovered measure column.
         activeMeasures.add(e.column);
       }
       if (activeMeasures.isEmpty) {
         for (var series in _area.config.series) {
           activeMeasures.addAll(series.measures);
         }
       }
       activeMeasures.sort();
@@ skipping 48 matching lines @@
         : orientation;
 
     if (direction == ORIENTATION_LEFT) {
       x = coord.x - rect.width - _TOOLTIP_OFFSET;
       y = coord.y + _TOOLTIP_OFFSET;
     } else {
       x = coord.x + _TOOLTIP_OFFSET;
       y = coord.y + _TOOLTIP_OFFSET;
     }
     return boundTooltipPosition(
-        new math.Rectangle(x, y, rect.width, rect.height));
+        new math.Rectangle(x as num, y as num, rect.width, rect.height));
   }
 
   /// Positions the tooltip to be inside of the chart boundary.
   math.Point boundTooltipPosition(math.Rectangle rect) {
     var hostRect = _area.host.getBoundingClientRect();
 
     var top = rect.top;
     var left = rect.left;
 
     // Checks top and bottom.
@@ skipping 14 matching lines @@
   }
 
   FormatFunction _getFormatterForColumn(int column) =>
       _area.data.columns.elementAt(column).formatter;
 
   hide(ChartEvent e) {
     if (_tooltipRoot == null) return;
     _tooltipRoot.style('opacity', '0');
   }
 }