Refactor Future constructors.

runtime/lib/deferred_load_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.
 
 final Set<String> _loadedLibraries = new Set<String>();
 
 patch class DeferredLibrary {
   /* patch */ Future<bool> load() {
     // Dummy implementation that should eventually be replaced by real
     // implementation.
     Future future =
-        new Future<bool>.immediate(!_loadedLibraries.contains(libraryName));
+        new Future<bool>.value(!_loadedLibraries.contains(libraryName));
     _loadedLibraries.add(libraryName);
     return future;
   }
 }