Revert r43217, r43215, r43208, r43207, and r43202.

runtime/bin/vmservice/vmservice_io.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_io;
 
 import 'dart:async';
 import 'dart:convert';
 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;
 // Should the HTTP server auto start?
 bool _autoStart;
 
 bool _isWindows = false;
 
-var _signalWatch;
-
 // HTTP servr.
 Server server;
 Future<Server> serverFuture;
 
 void _bootServer() {
   // Load resources.
   _triggerResourceLoad();
   // Lazily create service.
   var service = new VMService();
   // Lazily create server.
@@ skipping 13 matching lines @@
     _bootServer();
   }
   // Toggle HTTP server.
   if (server.running) {
     serverFuture = server.shutdown(true).then(_clearFuture);
   } else {
     serverFuture = server.startup().then(_clearFuture);
   }
 }
 
-void _registerSignalHandler() {
+void _registerSignalHandler(Stream signalWatch(ProcessSignal signal)) {
   if (_isWindows) {
     // Cannot register for signals on Windows.
     return;
   }
-  _signalWatch(ProcessSignal.SIGQUIT).listen(_onSignal);
+  signalWatch(ProcessSignal.SIGQUIT).listen(_onSignal);
 }
 
-const _shortDelay = const Duration(milliseconds: 10);
-
-main() {
+main(Stream signalWatch(ProcessSignal signal)) {
   if (_autoStart) {
     _bootServer();
     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;
-  // Register signal handler after a small delay to avoid stalling main
-  // isolate startup.
-  new Timer(_shortDelay, _registerSignalHandler);
-  return scriptLoadPort;
+  _registerSignalHandler(signalWatch);
 }