Update charted to 0.4.8 and roll

packages/charted/lib/charts/src/chart_config_impl.dart

Index: packages/charted/lib/charts/src/chart_config_impl.dart
diff --git a/packages/charted/lib/charts/src/chart_config_impl.dart b/packages/charted/lib/charts/src/chart_config_impl.dart
index 80bedafbbbb449be42490989a246170387f35a0f..3290dcab2892cec6fb0a9ecb1d8b8cd5a4595634 100644
--- a/packages/charted/lib/charts/src/chart_config_impl.dart
+++ b/packages/charted/lib/charts/src/chart_config_impl.dart
@@ -8,7 +8,7 @@
 
 part of charted.charts;
 
-class DefaultChartConfigImpl extends ChangeNotifier implements ChartConfig {
+class DefaultChartConfigImpl extends Observable implements ChartConfig {
   final Map<String, ChartAxisConfig> _measureAxisRegistry = {};
   final Map<int, ChartAxisConfig> _dimensionAxisRegistry = {};
   final SubscriptionsDisposer _disposer = new SubscriptionsDisposer();
@@ -110,6 +110,7 @@ class DefaultChartConfigImpl extends ChangeNotifier implements ChartConfig {
   void registerMeasureAxis(String id, ChartAxisConfig config) {
     assert(config != null);
     _measureAxisRegistry[id] = config;
+    notifyChange(const ChartConfigChangeRecord());
   }
 
   @override
@@ -120,6 +121,7 @@ class DefaultChartConfigImpl extends ChangeNotifier implements ChartConfig {
     assert(config != null);
     assert(dimensions.contains(column));
     _dimensionAxisRegistry[column] = config;
+    notifyChange(const ChartConfigChangeRecord());
   }
 
   @override