Implement scheduleImmediate for the VM.

runtime/lib/schedule_microtask_patch.dart

 // Copyright (c) 2013, 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.
 
-patch class _AsyncRun {
-  /* patch */ static void _scheduleImmediate(void callback()) {
-    if (_ScheduleImmediate._closure == null) {
-      // TODO(9001): don't default to using the Timer to enqueue the immediate
-      //             callback.
-      _createTimer(Duration.ZERO, callback);
-      return;
-    }
-    _ScheduleImmediate._closure(callback);
-  }
+@deprecated

[floitsch, 2013/11/20 19:37:13]

I need to update Dartium before I can remove this function.
Once this CL is committed it is a trivial patch to switch Dartium (without ever
going red on the buildbot).

+void _setScheduleImmediateClosure(ScheduleImmediateClosure closure) {
+  scheduleImmediateClosure = closure;
 }
-
-typedef void _ScheduleImmediateClosure(void callback());
-
-class _ScheduleImmediate {
-  static _ScheduleImmediateClosure _closure;
-}
-
-void _setScheduleImmediateClosure(_ScheduleImmediateClosure closure) {
-  _ScheduleImmediate._closure = closure;
-}