Implement scheduleImmediate for the VM.

runtime/bin/builtin.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.
 
 library builtin;
 import 'dart:io';
+import 'dart:async';
 // import 'root_library'; happens here from C Code
 
 // The root library (aka the script) is imported into this library. The
 // standalone embedder uses this to lookup the main entrypoint in the
 // root library's namespace.
 Function _getMainClosure() => main;
 
 
 // Corelib 'print' implementation.
 void _print(arg) {
@@ skipping 67 matching lines @@
               .fold(new BytesBuilder(), (b, d) => b..add(d))
               .then((builder) {
                 _requestCompleted(builder.takeBytes(), response);
               });
         }).catchError((error) {
           _requestFailed(error);
         });
   } catch (error) {
     _requestFailed(error);
   }
+  // TODO(floitsch): remove this line. It's just here to push an event on the
+  // event loop so that we invoke the scheduled microtasks. Also remove the
+  // import of dart:async when this line is not needed anymore.
+  Timer.run(() {});
 }
 
 
 // Are we running on Windows?
 var _isWindows = false;
 var _workingWindowsDrivePrefix;
 // The current working directory
 var _workingDirectoryUri;
 // The URI that the entry point script was loaded from. Remembered so that
 // package imports can be resolved relative to it.
@@ skipping 158 matching lines @@
 
     throw "URIs using the 'package:' scheme should look like "
           "'$right', not '$wrong'.";
   }
 
   var packageRoot = _packageRoot == null ?
                     _entryPointScript.resolve('packages/') :
                     _packageRoot;
   return _filePathFromUri(packageRoot.resolve(uri.path).toString());
 }