Dart: Lazy observatory asset loading. Option to disable the observatory.

mojo/dart/embedder/vmservice/main.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 dart_controller_service_isolate;
 
 import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
 import 'dart:isolate';
 import 'dart:_vmservice';
 
 part 'loader.dart';
 part 'server.dart';
 
 // The TCP ip/port that the HTTP server listens on.
 int _port;
 String _ip;
 // Should the HTTP server auto start?
 bool _autoStart;
 
 // HTTP server.
 Server server;
-Map<String, Asset> assets;
+Map<String, Asset> _assets;
+Map<String, Asset> get assets {
+  if (_assets == null) {
+    try {
+      _assets = Asset.request();
+    } catch (e) {
+      print('Could not load Observatory assets: $e');
+    }
+  }
+  return _assets;
+}
 
 _onShutdown() {
   if (server != null) {
     server.close(true).catchError((e, st) {
       print(e);
     }).whenComplete(_shutdown);
   } else {
     _shutdown();
   }
 }
 
 void _bootServer() {
-  try {
-    assets = Asset.request();
-  } catch (e) {
-    print('Could not load Observatory assets: $e');
-  }
   // Lazily create service.
   var service = new VMService();
   service.onShutdown = _onShutdown;
   // Lazily create server.
   server = new Server(service, _ip, _port);
 }
 
 main() {
   if (_autoStart) {
     _bootServer();
     if (server != null) {
       server.startup();
     }
+    // It's just here to push an event on the event loop so that we invoke the
+    // scheduled microtasks.
+    Timer.run(() {});
   }
   scriptLoadPort.handler = _processLoadRequest;
-  // It's just here to push an event on the event loop so that we invoke the
-  // scheduled microtasks.
-  Timer.run(() {});
   return scriptLoadPort;
 }
 
 _shutdown() native "ServiceIsolate_Shutdown";