Add VMService GC events

runtime/bin/vmservice/observatory/lib/src/service/object.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.
 
 part of service;
 
 /// A [ServiceObject] is an object known to the VM service and is tied
 /// to an owning [Isolate].
 abstract class ServiceObject extends Observable {
   static int LexicalSortName(ServiceObject o1, ServiceObject o2) {
@@ skipping 252 matching lines @@
       }
       if (map['type'] != 'ServiceEvent') {
         Logger.root.severe(
             "Expected 'ServiceEvent' but found '${map['type']}'");
         return;
       }
 
       // Extract the owning isolate from the event itself.
       String owningIsolateId = map['isolate']['id'];
       _getIsolate(owningIsolateId).then((owningIsolate) {
-          var event = new ServiceObject._fromMap(owningIsolate, map);
-          events.add(event);
+          if (owningIsolate == null) {
+            // TODO(koda): Do we care about GC events in VM isolate?
+            Logger.root.severe(
+                'Ignoring event with unknown isolate id: $owningIsolateId');
+          } else {
+            var event = new ServiceObject._fromMap(owningIsolate, map);
+            events.add(event);
+          }
       });
   }
 
   static final RegExp _currentIsolateMatcher = new RegExp(r'isolates/\d+');
   static final RegExp _currentObjectMatcher = new RegExp(r'isolates/\d+/');
   static final String _isolatesPrefix = 'isolates/';
 
   String _parseObjectId(String id) {
     Match m = _currentObjectMatcher.matchAsPrefix(id);
     if (m == null) {
@@ skipping 1948 matching lines @@
     var v = list[i];
     if ((v is ObservableMap) && _isServiceMap(v)) {
       list[i] = owner.getFromMap(v);
     } else if (v is ObservableList) {
       _upgradeObservableList(v, owner);
     } else if (v is ObservableMap) {
       _upgradeObservableMap(v, owner);
     }
   }
 }