Add Observatory to sky dart_controller

sky/engine/core/script/dart_service_isolate/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;
+library sky_shell_dart_controller_service_isolate;
 
 import 'dart:async';
 import 'dart:convert';
-import 'dart:mojo.io';
+import 'dart:io';
 import 'dart:isolate';
 import 'dart:vmservice';
 
 part 'loader.dart';
 part 'resources.dart';
 part 'server.dart';
 
 // The TCP ip/port that the HTTP server listens on.
 int _port;
 String _ip;
@@ skipping 31 matching lines @@
     }
   }
   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";