First pass at asynchronous input loading in dart2js.

tests/compiler/dart2js/simple_inferrer_final_field2_test.dart

Index: tests/compiler/dart2js/simple_inferrer_final_field2_test.dart
diff --git a/tests/compiler/dart2js/simple_inferrer_final_field2_test.dart b/tests/compiler/dart2js/simple_inferrer_final_field2_test.dart
index e03c4f37fe64f7d61eeac03561d6abcb840a197a..86e03b3f21d53889fcd6aaec4b005a6bcb108448 100644
--- a/tests/compiler/dart2js/simple_inferrer_final_field2_test.dart
+++ b/tests/compiler/dart2js/simple_inferrer_final_field2_test.dart
@@ -26,15 +26,16 @@ main() {
 void main() {
   Uri uri = new Uri(scheme: 'source');
   var compiler = compilerFor(TEST, uri);
-  compiler.runCompiler(uri);
-  var typesInferrer = compiler.typesTask.typesInferrer;
-
-  checkFieldTypeInClass(String className, String fieldName, type) {
-    var cls = findElement(compiler, className);
-    var element = cls.lookupLocalMember(buildSourceString(fieldName));
-    Expect.equals(type, typesInferrer.internal.typeOf[element]);
-  }
-
-  checkFieldTypeInClass('A', 'intField', typesInferrer.intType);
-  checkFieldTypeInClass('A', 'stringField', typesInferrer.stringType);
+  compiler.runCompiler(uri).then((_) {
+    var typesInferrer = compiler.typesTask.typesInferrer;
+
+    checkFieldTypeInClass(String className, String fieldName, type) {
+      var cls = findElement(compiler, className);
+      var element = cls.lookupLocalMember(buildSourceString(fieldName));
+      Expect.equals(type, typesInferrer.internal.typeOf[element]);
+    }
+
+    checkFieldTypeInClass('A', 'intField', typesInferrer.intType);
+    checkFieldTypeInClass('A', 'stringField', typesInferrer.stringType);
+  });
 }