Upgrade Observatory to Polymer 0.10.x

runtime/bin/vmservice/client/lib/src/elements/isolate_summary.dart

Index: runtime/bin/vmservice/client/lib/src/elements/isolate_summary.dart
diff --git a/runtime/bin/vmservice/client/lib/src/elements/isolate_summary.dart b/runtime/bin/vmservice/client/lib/src/elements/isolate_summary.dart
index 7054ba18b5c549cf77f36e62bcfe44e7b43cc93d..53357828a13096ed48932552047d850539ccb81d 100644
--- a/runtime/bin/vmservice/client/lib/src/elements/isolate_summary.dart
+++ b/runtime/bin/vmservice/client/lib/src/elements/isolate_summary.dart
@@ -89,12 +89,19 @@ class IsolateCounterChartElement extends ObservatoryElement {
   IsolateCounterChartElement.created() : super.created();
 
   @published ObservableMap counters;
-  CounterChart chart = new CounterChart();
+  CounterChart chart;
 
   void countersChanged(oldValue) {
     if (counters == null) {
       return;
     }
+    // Lazily create the chart.
+    if (GoogleChart.ready && chart == null) {
+      chart = new CounterChart();
+    }
+    if (chart == null) {
+      return;
+    }
     chart.update(counters);
     var element = shadowRoot.querySelector('#counterPieChart');
     if (element != null) {