Dart: Simplifies the handle watcher. Various cleanups and bugfixes.

mojo/dart/test/handle_finalizer_test.dart

 // Copyright 2014 The Chromium Authors. 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:async';
 import 'dart:isolate';
 import 'dart:mojo_core';
 import 'dart:typed_data';
 
 import 'package:mojo/dart/testing/expect.dart';
 
-RawMojoHandle leakMojoHandle() {
+MojoHandle leakMojoHandle() {
   var pipe = new MojoMessagePipe();
   Expect.isNotNull(pipe);
 
   var endpoint = pipe.endpoints[0];
   Expect.isTrue(endpoint.handle.isValid);
 
-  var handle = new MojoHandle(endpoint.handle);
+  var eventStream = new MojoEventStream(endpoint.handle);
   // After making a high-level MojoHandle, the underlying mojo handle will have
   // the native MojoClose called on it when the MojoHandle is GC'd or the VM
   // shuts down.
 
   return endpoint.handle;
 }
 
 // vmoptions: --new-gen-semi-max-size=1 --old_gen_growth_rate=1
 List<int> triggerGC() {
   var l = new List.filled(1000000, 7);
   return l;
 }
 
 test() {
-  RawMojoHandle handle = leakMojoHandle();
+  MojoHandle handle = leakMojoHandle();
   triggerGC();
 
   // The handle will be closed by the MojoHandle finalizer during GC, so the
   // attempt to close it again will fail.
   MojoResult result = handle.close();
   Expect.isTrue(result.isInvalidArgument);
 }
 
 main() {
   test();
 }