Add --break-at-isolate-spawn to help with isolate debugging.

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 774 matching lines @@
   @observable final rootClasses = new ObservableList<Class>();
 
   @observable Library rootLib;
   @observable ObservableList<Library> libraries =
       new ObservableList<Library>();
   @observable ObservableMap topFrame;
 
   @observable String name;
   @observable String vmName;
   @observable String mainPort;
-  @observable Map entry;
+  @observable ServiceFunction entry;
 
   @observable final Map<String, double> timers =
       toObservable(new Map<String, double>());
 
   final HeapSpace newSpace = new HeapSpace();
   final HeapSpace oldSpace = new HeapSpace();
 
   @observable String fileAndLine;
 
   @observable DartError error;
@@ skipping 1718 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);
     }
   }
 }