Reverting setTimeout removal.

tools/dom/templates/html/dartium/impl_Window.darttemplate

+// 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.
+
+part of $LIBRARYNAME;
+
+$(ANNOTATIONS)class $CLASSNAME$EXTENDS$IMPLEMENTS$NATIVESPEC {
+
+  /**
+   * Executes a [callback] after the immediate execution stack has completed.
+   *
+   * This will cause the callback to be executed after all processing has
+   * completed for the current event, but before any subsequent events.
+   */
+  void setImmediate(TimeoutHandler callback) {
+    _addMicrotaskCallback(callback);
+  }
+
+  /**
+   * Lookup a port by its [name].  Return null if no port is
+   * registered under [name].
+   */
+  lookupPort(String name) {
+    var port = json.parse(document.documentElement.attributes['dart-port:$name']);
+    return _deserialize(port);
+  }
+
+  /**
+   * Register a [port] on this window under the given [name].  This
+   * port may be retrieved by any isolate (or JavaScript script)
+   * running in this window.
+   */
+  registerPort(String name, var port) {
+    var serialized = _serialize(port);
+    document.documentElement.attributes['dart-port:$name'] = json.stringify(serialized);
+  }
+
+  /// Checks if _setImmediate is supported.
+  static bool get _supportsSetImmediate => false;
+
+  /// Dartium stub for IE's setImmediate.
+  void _setImmediate(void callback()) {
+    throw new UnsupportedError('setImmediate is not supported');
+  }
+
+$!MEMBERS
+}