Use patching for dart:io.

runtime/bin/eventhandler.dart

Index: runtime/bin/eventhandler.dart
diff --git a/runtime/bin/eventhandler.dart b/runtime/bin/eventhandler.dart
deleted file mode 100644
index 2e0a8fc1910a626b6d5e1dbec68331c966670193..0000000000000000000000000000000000000000
--- a/runtime/bin/eventhandler.dart
+++ /dev/null
@@ -1,27 +0,0 @@
-// Copyright (c) 2012, 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.
-
-class _EventHandler extends NativeFieldWrapperClass1 {
-  _EventHandler() { }
-
-  static void _start() {
-    if (_eventHandler === null) {
-      _eventHandler = new _EventHandler();
-      _eventHandler._doStart();
-    }
-  }
-
-  void _doStart() native "EventHandler_Start";
-
-  static _sendData(Object sender, ReceivePort receivePort, int data) {
-    if (_eventHandler !== null) {
-      _eventHandler._doSendData(sender, receivePort, data);
-    }
-  }
-
-  void _doSendData(Object sender, ReceivePort receivePort, int data)
-      native "EventHandler_SendData";
-
-  static _EventHandler _eventHandler;
-}