Upgrade Observatory to Polymer 0.10.x

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

 // Copyright (c) 2013, 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.
 
 library observatory_application_element;
 
 import 'observatory_element.dart';
 import 'package:observatory/app.dart';
 import 'package:polymer/polymer.dart';
 
 /// Main application tag. Responsible for instantiating an instance of
 /// [ObservatoryApplication] which is passed declaratively to all child
 /// elements.
 @CustomTag('observatory-application')
 class ObservatoryApplicationElement extends ObservatoryElement {
   @published bool devtools = false;
-  @observable ObservatoryApplication app;
+  @published ObservatoryApplication app;
 
-  ObservatoryApplicationElement.created() : super.created() {
+  ObservatoryApplicationElement.created() : super.created();
+
+  enteredView() {
+    super.enteredView();
     if (devtools) {
       app = new ObservatoryApplication.devtools();
     } else {
       app = new ObservatoryApplication();
     }
   }
 }