kernel->ssa: get simple constructors working

tests/compiler/dart2js/kernel/constructors_test.dart

Index: tests/compiler/dart2js/kernel/constructors_test.dart
diff --git a/tests/compiler/dart2js/kernel/constructors_test.dart b/tests/compiler/dart2js/kernel/constructors_test.dart
new file mode 100644
index 0000000000000000000000000000000000000000..1d30c1c548c02003058b1b7c0320a8f1bfccbff6
--- /dev/null
+++ b/tests/compiler/dart2js/kernel/constructors_test.dart
@@ -0,0 +1,41 @@
+// Copyright (c) 2016, 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.
+
+import 'package:compiler/src/compiler.dart' show Compiler;
+import 'package:compiler/src/elements/elements.dart';
+import 'package:test/test.dart';
+
+import 'helper.dart' show check;
+
+main() {
+  test('simple default constructor', () {
+    String code = '''
+class A {
+}
+
+main() {
+  var a = new A();
+  return a;
+}''';
+    return check(code, lookup: defaultConstructorFor('A'));
+  });
+
+  test('simple default constructor with field', () {
+    String code = '''
+class A {
+  int x = 1;
+}
+
+main() {
+  var a = new A();
+  return a;
+}''';
+    return check(code, lookup: defaultConstructorFor('A'));
+  });
+}
+
+defaultConstructorFor(String className) => (Compiler compiler) {
+      ClassElement clazz = compiler.mainApp.find(className);
+      return clazz.lookupDefaultConstructor();
+    };