Update charted to 0.4.8 and roll

packages/charted/lib/charts/cartesian_renderers/cartesian_base_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;
 
@@ skipping 61 matching lines @@
     _valueFilterCache.clear();
     _computeColumnStates();
   }
 
   /// Override this method to handle state changes.
   void handleStateChanges(List<ChangeRecord> changes);
 
   @override
   Extent get extent {
     assert(series != null && area != null);
-    var rows = area.data.rows,
-        measures = series.measures,
-        max = SMALL_INT_MIN,
-        min = SMALL_INT_MAX;
+    var rows = area.data.rows, measures = series.measures;
+    num max = SMALL_INT_MIN;
+    num min = SMALL_INT_MAX;
 
     for (int i = 0, len = rows.length; i < len; ++i) {
       var row = rows.elementAt(i);
       for (int j = 0, jLen = measures.length; j < jLen; ++j) {
         var value = row.elementAt(measures.elementAt(j));
         if (value != null && value.isFinite) {
           if (value > max) {
             max = value;
           } else if (value < min) {
             min = value;
           }
         }
       }
     }
+
+    // If all values are null or non finite, set the extent to be 0.
+    if (max == SMALL_INT_MIN && min == SMALL_INT_MAX) {
+      max = 0;
+      min = 0;
+    }
     return new Extent(min, max);
   }
 
   @override
   Extent extentForRow(Iterable row) {
     assert(series != null && area != null);
     var measures = series.measures, max = SMALL_INT_MIN, min = SMALL_INT_MAX;
 
     for (int i = 0, len = measures.length; i < len; ++i) {
       var measure = measures.elementAt(i), value = row.elementAt(measure);
@@ skipping 159 matching lines @@
       }
       if (state.hovered != null && state.hovered.last == row) {
         flags |= ChartState.VAL_HOVERED;
       }
       _valueColorCache[hash] =
           theme.getColorForKey(area.useRowColoring ? row : column, flags);
       _valueFilterCache[hash] = theme.getFilterForState(flags);
     }
   }
 }