Add flutter_web samples (#75)

web/charts/flutter/lib/src/scatter_plot_chart.dart

@@ -0,0 +1,82 @@
+// Copyright 2018 the Charts project authors. Please see the AUTHORS file
+// for details.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+import 'dart:collection' show LinkedHashMap;
+
+import 'package:charts_common/common.dart' as common
+    show
+        AxisSpec,
+        NumericAxisSpec,
+        PointRendererConfig,
+        RTLSpec,
+        ScatterPlotChart,
+        SeriesRendererConfig,
+        Series;
+import 'behaviors/chart_behavior.dart' show ChartBehavior;
+import 'base_chart.dart' show LayoutConfig;
+import 'base_chart_state.dart' show BaseChartState;
+import 'cartesian_chart.dart' show CartesianChart;
+import 'selection_model_config.dart' show SelectionModelConfig;
+import 'user_managed_state.dart' show UserManagedState;
+
+class ScatterPlotChart extends CartesianChart<num> {
+  ScatterPlotChart(
+    List<common.Series> seriesList, {
+    bool animate,
+    Duration animationDuration,
+    common.AxisSpec domainAxis,
+    common.AxisSpec primaryMeasureAxis,
+    common.AxisSpec secondaryMeasureAxis,
+    LinkedHashMap<String, common.NumericAxisSpec> disjointMeasureAxes,
+    common.PointRendererConfig<num> defaultRenderer,
+    List<common.SeriesRendererConfig<num>> customSeriesRenderers,
+    List<ChartBehavior> behaviors,
+    List<SelectionModelConfig<num>> selectionModels,
+    common.RTLSpec rtlSpec,
+    LayoutConfig layoutConfig,
+    bool defaultInteractions: true,
+    bool flipVerticalAxis,
+    UserManagedState<num> userManagedState,
+  }) : super(
+          seriesList,
+          animate: animate,
+          animationDuration: animationDuration,
+          domainAxis: domainAxis,
+          primaryMeasureAxis: primaryMeasureAxis,
+          secondaryMeasureAxis: secondaryMeasureAxis,
+          disjointMeasureAxes: disjointMeasureAxes,
+          defaultRenderer: defaultRenderer,
+          customSeriesRenderers: customSeriesRenderers,
+          behaviors: behaviors,
+          selectionModels: selectionModels,
+          rtlSpec: rtlSpec,
+          layoutConfig: layoutConfig,
+          defaultInteractions: defaultInteractions,
+          flipVerticalAxis: flipVerticalAxis,
+          userManagedState: userManagedState,
+        );
+
+  @override
+  common.ScatterPlotChart createCommonChart(BaseChartState chartState) {
+    // Optionally create primary and secondary measure axes if the chart was
+    // configured with them. If no axes were configured, then the chart will
+    // use its default types (usually a numeric axis).
+    return new common.ScatterPlotChart(
+        layoutConfig: layoutConfig?.commonLayoutConfig,
+        primaryMeasureAxis: primaryMeasureAxis?.createAxis(),
+        secondaryMeasureAxis: secondaryMeasureAxis?.createAxis(),
+        disjointMeasureAxes: createDisjointMeasureAxes());
+  }
+}