getIsolate rpc now returns collected sentinel for expired isolate.

runtime/vm/service/vmservice.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 vmservice;
 
 import 'dart:async';
 import 'dart:convert';
 import 'dart:isolate';
 import 'dart:typed_data';
@@ skipping 33 matching lines @@
     },
   };
   if (details != null) {
     response['error']['data'] = {
       'details': details,
     };
   }
   return JSON.encode(response);
 }
 
+String encodeResult(Message message, Map result) {
+  var response = {
+    'jsonrpc': '2.0',
+    'id' : message.serial,
+    'result' : result,
+  };
+  return JSON.encode(response);
+}
+
+
 class VMService extends MessageRouter {
   static VMService _instance;
 
   /// Collection of currently connected clients.
   final Set<Client> clients = new Set<Client>();
 
   /// Collection of currently running isolates.
   RunningIsolates runningIsolates = new RunningIsolates();
 
   /// A port used to receive events from the VM.
@@ skipping 102 matching lines @@
     var members = [];
     var result = {};
     clients.forEach((client) {
       members.add(client.toJson());
     });
     result['type'] = 'ClientList';
     result['members'] = members;
     message.setResponse(JSON.encode(result));
   }
 
-  String _encodeResult(Message message, Map result) {
-    var response = {
-      'jsonrpc': '2.0',
-      'id' : message.serial,
-      'result' : result,
-    };
-    return JSON.encode(response);
-  }
-
   bool _isAnyClientSubscribed(String streamId) {
     for (var client in clients) {
       if (client.streams.contains(streamId)) {
         return true;
       }
     }
     return false;
   }
 
   Future<String> _streamListen(Message message) async {
     var client = message.client;
     var streamId = message.params['streamId'];
 
     if (client.streams.contains(streamId)) {
       return encodeRpcError(message, kStreamAlreadySubscribed);
     }
     if (!_isAnyClientSubscribed(streamId)) {
       if (!_vmListenStream(streamId)) {
         return encodeRpcError(
             message, kInvalidParams,
             details:"streamListen: invalid 'streamId' parameter: ${streamId}");
       }
     }
     client.streams.add(streamId);
 
     var result = { 'type' : 'Success' };
-    return _encodeResult(message, result);
+    return encodeResult(message, result);
   }
 
   Future<String> _streamCancel(Message message) async {
     var client = message.client;
     var streamId = message.params['streamId'];
 
     if (!client.streams.contains(streamId)) {
       return encodeRpcError(message, kStreamNotSubscribed);
     }
     client.streams.remove(streamId);
     if (!_isAnyClientSubscribed(streamId)) {
       _vmCancelStream(streamId);
     }
 
     var result = { 'type' : 'Success' };
-    return _encodeResult(message, result);
+    return encodeResult(message, result);
   }
 
   // TODO(johnmccutchan): Turn this into a command line tool that uses the
   // service library.
   Future<String> _getCrashDump(Message message) async {
     var client = message.client;
     final perIsolateRequests = [
         // ?isolateId=<isolate id> will be appended to each of these requests.
         // Isolate information.
         Uri.parse('getIsolate'),
@@ skipping 37 matching lines @@
       var response = JSON.decode(await isolate.route(message));
       // Insert getObject requests into responses map.
       for (var object in response['result']['objects']) {
         final requestUri =
             'getObject&isolateId=${isolate.serviceId}?objectId=${object["id"]}';
         responses[requestUri] = object;
       }
     }
 
     // Encode the entire crash dump.
-    return _encodeResult(message, responses);
+    return encodeResult(message, responses);
   }
 
   Future<String> route(Message message) {
     if (message.completed) {
       return message.response;
     }
     // TODO(turnidge): Update to json rpc.  BEFORE SUBMIT.
     if ((message.path.length == 1) && (message.path[0] == 'clients')) {
       _clientCollection(message);
       return message.response;
@@ skipping 24 matching lines @@
   service.runningIsolates.isolateStartup(port_id, sp, name);
 }
 
 void _onStart() native "VMService_OnStart";
 
 void _onExit() native "VMService_OnExit";
 
 bool _vmListenStream(String streamId) native "VMService_ListenStream";
 
 void _vmCancelStream(String streamId) native "VMService_CancelStream";