Teach the Observatory about WeakProperties (ephemerons).

runtime/bin/vmservice/observatory/lib/src/elements/service_view.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 service_object_view_element;
 
 import 'dart:html';
 import 'package:logging/logging.dart';
 import 'package:observatory/service.dart';
 import 'package:observatory/tracer.dart';
@@ skipping 58 matching lines @@
       case 'Int32x4':
       case 'Float32x4':
       case 'Float64x4':
       case 'TypedData':
       case 'ExternalTypedData':
       case 'Capability':
       case 'ReceivePort':
       case 'SendPort':
       case 'Stacktrace':
       case 'JSRegExp':
-      case 'WeakProperty':
       case 'UserTag':
         // TODO(turnidge): The types above this comment are instance
         // types and should be handled by the InstanceViewElement.  We
         // need to go through these and make sure that they print in a
         // reasonable way.
       case 'Type':
       case 'Array':
       case 'Bool':
       case 'Closure':
       case 'Double':
       case 'GrowableObjectArray':
       case 'Instance':
       case 'Smi':
       case 'Mint':
       case 'MirrorReference':
       case 'Null':
       case 'Bigint':
       case 'String':
+      case 'WeakProperty':
         InstanceViewElement element = new Element.tag('instance-view');
         element.instance = object;
         return element;
       case 'IO':
         IOViewElement element = new Element.tag('io-view');
         element.io = object;
         return element;
       case 'HttpServerList':
         IOHttpServerListViewElement element =
             new Element.tag('io-http-server-list-view');
@@ skipping 151 matching lines @@
 
   dynamic expander() {
     return expandEvent;
   }
 
   void expandEvent(bool exp, var done) {
     expand = exp;
     done();
   }
 }