Take type arguments into account in interface type subtype check.

tests/compiler/dart2js/type_test_helper.dart

Index: tests/compiler/dart2js/type_test_helper.dart
diff --git a/tests/compiler/dart2js/type_test_helper.dart b/tests/compiler/dart2js/type_test_helper.dart
new file mode 100644
index 0000000000000000000000000000000000000000..94faaced6fc73d986ecabb64dd008ee8fa42094c
--- /dev/null
+++ b/tests/compiler/dart2js/type_test_helper.dart
@@ -0,0 +1,50 @@
+// 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.
+
+library type_test_helper;
+
+import '../../../sdk/lib/_internal/compiler/implementation/dart_types.dart';
+import "compiler_helper.dart";
+
+InterfaceType instantiate(ClassElement element, List<DartType> arguments) {
+  return new InterfaceType(element, new Link<DartType>.fromList(arguments));
+}
+
+class TypeEnvironment {
+  final MockCompiler compiler;
+
+  factory TypeEnvironment(String source) {
+    var uri = new Uri.fromComponents(scheme: 'source');
+    MockCompiler compiler = compilerFor('''
+        main() {}
+        $source''',
+        uri);
+    compiler.runCompiler(uri);
+    return new TypeEnvironment._(compiler);
+  }
+
+  TypeEnvironment._(MockCompiler this.compiler);
+
+  Element getElement(String name) {
+    var element = findElement(compiler, name);
+    Expect.isNotNull(element);
+    if (identical(element.kind, ElementKind.CLASS)) {
+      element.ensureResolved(compiler);
+    }
+    return element;
+  }
+
+  DartType getElementType(String name) {
+    return getElement(name).computeType(compiler);
+  }
+
+  DartType operator[] (String name) {
+    if (name == 'dynamic') return compiler.types.dynamicType;
+    return getElementType(name);
+  }
+
+  bool isSubtype(DartType T, DartType S) {
+    return compiler.types.isSubtype(T, S);
+  }
+}