Switch from Google charts to Charted

runtime/observatory/web/main.dart

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 import 'package:logging/logging.dart';
-import 'package:observatory/app.dart';
 import 'package:polymer/polymer.dart';
 
 main() {
   Logger.root.level = Level.INFO;
   Logger.root.onRecord.listen((LogRecord rec) {
       if (rec.level == Level.WARNING &&
           rec.message.startsWith('Error evaluating expression') &&
           (rec.message.contains("Can't assign to null: ") ||
            rec.message.contains('Expression is not assignable: '))) {
         // Suppress flaky polymer errors.
         return;
       }
       print('${rec.level.name}: ${rec.time}: ${rec.message}');
   });
   Logger.root.info('Starting Observatory');
-  var chartsLoaded = GoogleChart.initOnce();
-  chartsLoaded.then((_) {
-    // Charts loaded, initialize polymer.
-    initPolymer().then((zone) {
-      Logger.root.info('Polymer initialized');
-      // Code here is in the polymer Zone, which ensures that
-      // @observable properties work correctly.
-      Polymer.onReady.then((_) {
-        Logger.root.info('Polymer elements have been upgraded');
-      });
+  initPolymer().then((zone) {
+    Logger.root.info('Polymer initialized');
+    // Code here is in the polymer Zone, which ensures that
+    // @observable properties work correctly.
+    Polymer.onReady.then((_) {
+      Logger.root.info('Polymer elements have been upgraded');
     });
   });
 }