Roll Observatory packages and add a roll script

packages/charted/examples/charts/renderers/demo_stacked_bar_charts.dart

+
+library charted.demo.charts.stacked_bar_charts;
+
+import "dart:html";
+import "package:charted/charts/charts.dart";
+import "../demo_charts.dart";
+
+void drawSimpleStackedChart(String selector) {
+  var wrapper = document.querySelector(selector),
+      areaHost = wrapper.querySelector('.chart-host'),
+      legendHost = wrapper.querySelector('.chart-legend-host');
+
+  var series = new ChartSeries("one", [1, 2, 3], new StackedBarChartRenderer()),
+      config = new ChartConfig([series], [0])
+        ..legend = new ChartLegend(legendHost),
+      data = new ChartData(
+          ORDINAL_DATA_COLUMNS, ORDINAL_DATA),
+      state = new ChartState();
+
+  var area = new CartesianArea(areaHost, data, config, state: state);
+
+  createDefaultCartesianBehaviors().forEach((behavior) {
+    area.addChartBehavior(behavior);
+  });
+  area.draw();
+}
+
+void drawHorizontalStackedChart(String selector) {
+  var wrapper = document.querySelector(selector),
+      areaHost = wrapper.querySelector('.chart-host'),
+      legendHost = wrapper.querySelector('.chart-legend-host');
+
+  var series = new ChartSeries("one", [1, 2, 3], new StackedBarChartRenderer()),
+      config = new ChartConfig([series], [0])
+        ..legend = new ChartLegend(legendHost)
+        ..isLeftAxisPrimary = true,
+      data = new ChartData(
+          ORDINAL_DATA_COLUMNS, ORDINAL_DATA),
+      state = new ChartState();
+
+  var area = new CartesianArea(areaHost, data, config, state: state);
+
+  createDefaultCartesianBehaviors().forEach((behavior) {
+    area.addChartBehavior(behavior);
+  });
+  area.draw();
+}
+
+main() {
+  drawSimpleStackedChart('#simple-stacked-chart');
+  drawHorizontalStackedChart('#horizontal-stacked-chart');
+}
+