Add the streamListen and streamCancel rpcs to the vm service.

runtime/observatory/lib/src/app/page.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 app;
 
 class IsolateNotFound implements Exception {
   String isolateId;
   IsolateNotFound(this.isolateId);
   String toString() => "IsolateNotFound: $isolateId";
@@ skipping 173 matching lines @@
 
 class DebuggerPage extends SimplePage {
   DebuggerPage(app) : super('debugger', 'debugger-page', app);
 
   void _visit(Uri uri) {
     super._visit(uri);
     getIsolate(uri).then((isolate) {
       if (element != null) {
         /// Update the page.
         DebuggerPageElement page = element;
-        page.app = app;
         page.isolate = isolate;
       }
     });
   }
 }
 
 class CpuProfilerPage extends SimplePage {
   CpuProfilerPage(app) : super('profiler', 'cpu-profile', app);
 
   void _visit(Uri uri) {
@@ skipping 168 matching lines @@
   void _visit(Uri uri) {
     assert(element != null);
     assert(canVisit(uri));
     app.vm.getIsolate(uri.queryParameters['isolateId']).then((i) {
       (element as MetricsPageElement).isolate = i;
     });
   }
 
   bool canVisit(Uri uri) => uri.path == 'metrics';
 }