Unify dart:isolate.

lib/isolate/dart2js/timer_provider.dart

-// 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.
-
-
-// We don't want to import the DOM library just because of window.setTimeout,
-// so we reconstruct the Window class here. The only conflict that could happen
-// with the other DOMWindow class would be because of subclasses.
-// Currently, none of the two Dart classes have subclasses.
-typedef void _TimeoutHandler();
-
-class _Window native "@*DOMWindow" {
-  int setTimeout(_TimeoutHandler handler, int timeout) native;
-  int setInterval(_TimeoutHandler handler, int timeout) native;
-}
-
-_Window get _window() =>
-  JS('bool', 'typeof window != "undefined"') ? JS('_Window', 'window') : null;
-
-class _Timer implements Timer {
-  final bool _once;
-  int _handle;
-
-  _Timer(int milliSeconds, void callback(Timer timer))
-      : _once = true {
-    _handle = _window.setTimeout(() => callback(this), milliSeconds);
-  }
-
-  _Timer.repeating(int milliSeconds, void callback(Timer timer))
-      : _once = false {
-    _handle = _window.setInterval(() => callback(this), milliSeconds);
-  }
-
-  void cancel() {
-    if (_once) {
-      _window.clearTimeout(_handle);
-    } else {
-      _window.clearInterval(_handle);
-    }
-  }
-}
-
-Timer _timerFactory(int millis, void callback(Timer timer), bool repeating) =>
-  repeating ? new _Timer.repeating(millis, callback)
-            : new _Timer(millis, callback);