web/chart: fix sample (#909)

web/charts/lib/behaviors/slider.dart

@@ -36,11 +36,11 @@ class SliderLine extends StatefulWidget {
   final List<charts.Series> seriesList;
   final bool animate;
 
-  SliderLine(this.seriesList, {this.animate});
+  const SliderLine(this.seriesList, {this.animate, Key key}) : super(key: key);
 
   /// Creates a [LineChart] with sample data and no transition.
   factory SliderLine.withSampleData() {
-    return new SliderLine(
+    return SliderLine(
       _createSampleData(),
       // Disable animations for image tests.
       animate: false,
@@ -52,22 +52,22 @@ class SliderLine extends StatefulWidget {
   // It is used for creating random series data to demonstrate animation in
   // the example app only.
   factory SliderLine.withRandomData() {
-    return new SliderLine(_createRandomData());
+    return SliderLine(_createRandomData());
   }
 
   /// Create random data.
   static List<charts.Series<LinearSales, num>> _createRandomData() {
-    final random = new Random();
+    final random = Random();
 
     final data = [
-      new LinearSales(0, random.nextInt(100)),
-      new LinearSales(1, random.nextInt(100)),
-      new LinearSales(2, random.nextInt(100)),
-      new LinearSales(3, random.nextInt(100)),
+      LinearSales(0, random.nextInt(100)),
+      LinearSales(1, random.nextInt(100)),
+      LinearSales(2, random.nextInt(100)),
+      LinearSales(3, random.nextInt(100)),
     ];
 
     return [
-      new charts.Series<LinearSales, int>(
+      charts.Series<LinearSales, int>(
         id: 'Sales',
         domainFn: (LinearSales sales, _) => sales.year,
         measureFn: (LinearSales sales, _) => sales.sales,
@@ -80,19 +80,19 @@ class SliderLine extends StatefulWidget {
   // We need a Stateful widget to build the selection details with the current
   // selection as the state.
   @override
-  State<StatefulWidget> createState() => new _SliderCallbackState();
+  State<StatefulWidget> createState() => _SliderCallbackState();
 
   /// Create one series with sample hard coded data.
   static List<charts.Series<LinearSales, int>> _createSampleData() {
     final data = [
-      new LinearSales(0, 5),
-      new LinearSales(1, 25),
-      new LinearSales(2, 100),
-      new LinearSales(3, 75),
+      LinearSales(0, 5),
+      LinearSales(1, 25),
+      LinearSales(2, 100),
+      LinearSales(3, 75),
     ];
 
     return [
-      new charts.Series<LinearSales, int>(
+      charts.Series<LinearSales, int>(
         id: 'Sales',
         domainFn: (LinearSales sales, _) => sales.year,
         measureFn: (LinearSales sales, _) => sales.sales,
@@ -126,9 +126,9 @@ class _SliderCallbackState extends State<SliderLine> {
   Widget build(BuildContext context) {
     // The children consist of a Chart and Text widgets below to hold the info.
     final children = <Widget>[
-      new SizedBox(
+      SizedBox(
           height: 150.0,
-          child: new charts.LineChart(
+          child: charts.LineChart(
             widget.seriesList,
             animate: widget.animate,
             // Configures a [Slider] behavior.
@@ -159,7 +159,7 @@ class _SliderCallbackState extends State<SliderLine> {
             // [style] takes in a [SliderStyle] configuration object, and
             // configures the color and sizing of the slider line and handle.
             behaviors: [
-              new charts.Slider(
+              charts.Slider(
                   initialDomainValue: 1.0, onChangeCallback: _onSliderChange),
             ],
           )),
@@ -167,23 +167,23 @@ class _SliderCallbackState extends State<SliderLine> {
 
     // If there is a slider change event, then include the details.
     if (_sliderDomainValue != null) {
-      children.add(new Padding(
-          padding: new EdgeInsets.only(top: 5.0),
-          child: new Text('Slider domain value: $_sliderDomainValue')));
+      children.add(Padding(
+          padding: const EdgeInsets.only(top: 5.0),
+          child: Text('Slider domain value: $_sliderDomainValue')));
     }
     if (_sliderPosition != null) {
-      children.add(new Padding(
-          padding: new EdgeInsets.only(top: 5.0),
-          child: new Text(
+      children.add(Padding(
+          padding: const EdgeInsets.only(top: 5.0),
+          child: Text(
               'Slider position: ${_sliderPosition.x}, ${_sliderPosition.y}')));
     }
     if (_sliderDragState != null) {
-      children.add(new Padding(
-          padding: new EdgeInsets.only(top: 5.0),
-          child: new Text('Slider drag state: $_sliderDragState')));
+      children.add(Padding(
+          padding: const EdgeInsets.only(top: 5.0),
+          child: Text('Slider drag state: $_sliderDragState')));
     }
 
-    return new Column(children: children);
+    return Column(children: children);
   }
 }