First pass at asynchronous input loading in dart2js.

tests/compiler/dart2js/static_closure_test.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.
 
 // Test that static functions are closurized as expected.
 
 import "package:expect/expect.dart";
+import "package:async_helper/async_helper.dart";
 import 'compiler_helper.dart';
 
 main() {
-  String code = compileAll(r'''main() { print(main); }''');
+  asyncTest(() => compileAll(r'''main() { print(main); }''').then((code) {
+    // At some point, we will have to closurize global functions
+    // differently, at which point this test will break. Then it is time
+    // to implement a way to call a Dart closure from JS foreign
+    // functions.
 
-  // At some point, we will have to closurize global functions
-  // differently, at which point this test will break. Then it is time
-  // to implement a way to call a Dart closure from JS foreign
-  // functions.
-
-  // If this test fail, please take a look at the use of
-  // toStringWrapper in captureStackTrace in js_helper.dart.
-  Expect.isTrue(code.contains(new RegExp(r'print\([$a-z]+\.main\$closure\);')));
+    // If this test fail, please take a look at the use of
+    // toStringWrapper in captureStackTrace in js_helper.dart.
+    Expect.isTrue(code.contains(
+        new RegExp(r'print\([$a-z]+\.main\$closure\);')));
+  }));
 }