Add the streamListen and streamCancel rpcs to the vm service.

runtime/observatory/lib/service_common.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.
 
 library service_common;
 
 import 'dart:async';
 import 'dart:convert';
 import 'dart:typed_data';
 
@@ skipping 192 matching lines @@
       offset += metaSize;
       var data = new ByteData.view(
           bytes.buffer,
           bytes.offsetInBytes + offset,
           bytes.lengthInBytes - offset);
       var map = _parseJSON(meta);
       if (map == null) {
         return;
       }
       var event = map['event'];
-      postServiceEvent(event, data);
+      var streamId = map['streamId'];
+      postServiceEvent(streamId, event, data);
     });
   }
 
   void _onStringMessage(String data) {
     var map = _parseJSON(data);
     if (map == null) {
       return;
     }
     var event = map['event'];
     if (event != null) {
-      postServiceEvent(event, null);
+      var streamId = map['streamId'];
+      postServiceEvent(streamId, event, null);
       return;
     }
 
     // Extract serial and result.
     var serial = map['id'];
 
     // Complete request.
     var request = _pendingRequests.remove(serial);
     if (request == null) {
       Logger.root.severe('Received unexpected message: ${map}');
@@ skipping 84 matching lines @@
     if (request.method != 'getTagProfile' &&
         request.method != 'getIsolateMetric' &&
         request.method != 'getVMMetric') {
       Logger.root.info(
           'GET [${serial}] ${request.method}(${request.params}) from ${target.networkAddress}');
     }
     // Send message.
     _webSocket.send(message);
   }
 }