Add expandable instances and lists to the vm service.

runtime/bin/vmservice/client/lib/src/observatory_elements/instance_ref.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 instance_ref_element;
 
+import 'package:logging/logging.dart';
 import 'package:polymer/polymer.dart';
 import 'service_ref.dart';
 
 @CustomTag('instance-ref')
 class InstanceRefElement extends ServiceRefElement {
   InstanceRefElement.created() : super.created();
 
+  @published bool expanded = false;
+
   String get name {
     if (ref == null) {
       return super.name;
     }
     return ref['preview'];
   }
-}
+
+  void toggleExpand(var a, var b, var c) {
+    if (expanded) {
+      ref['fields'] = null;
+      ref['elements'] = null;
+      expanded = false;
+    } else {
+      app.requestManager.requestMap(url).then((map) {
+          print(map);
+          ref['fields'] = map['fields'];
+          ref['elements'] = map['elements'];
+          ref['length'] = map['length'];
+          expanded = true;
+      }).catchError((e, trace) {
+          Logger.root.severe('Error while expanding instance-ref: $e\n$trace');
+      });
+    }
+  }
+}