Update charted to 0.4.8 and roll

packages/charted/lib/charts/cartesian_renderers/cartesian_base_renderer.dart

Index: packages/charted/lib/charts/cartesian_renderers/cartesian_base_renderer.dart
diff --git a/packages/charted/lib/charts/cartesian_renderers/cartesian_base_renderer.dart b/packages/charted/lib/charts/cartesian_renderers/cartesian_base_renderer.dart
index 92ccbd6bb185e0989c7479263c3b620cdb919597..1d682db8e29d2c6cd2e8e2bd1f02d0d29ff6928d 100644
--- a/packages/charted/lib/charts/cartesian_renderers/cartesian_base_renderer.dart
+++ b/packages/charted/lib/charts/cartesian_renderers/cartesian_base_renderer.dart
@@ -79,10 +79,9 @@ abstract class CartesianRendererBase implements CartesianRenderer {
   @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);
@@ -97,6 +96,12 @@ abstract class CartesianRendererBase implements CartesianRenderer {
         }
       }
     }
+
+    // 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);
   }