Merge more Kernel infrastructure from kernel_sdk SDK fork.

runtime/bin/eventhandler_patch.dart

Index: runtime/bin/eventhandler_patch.dart
diff --git a/runtime/bin/eventhandler_patch.dart b/runtime/bin/eventhandler_patch.dart
index effe402916419fc8dc7cec62978010c509295efa..588a4b82ab129ee7395b14c50b967dd6a34ed19d 100644
--- a/runtime/bin/eventhandler_patch.dart
+++ b/runtime/bin/eventhandler_patch.dart
@@ -2,8 +2,6 @@
 // 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.
 
-import 'dart:nativewrappers';
-
 @patch class _EventHandler {
   @patch static void _sendData(Object sender,
                                     SendPort sendPort,