Support for extending native classes

tests/compiler/dart2js_native/subclassing_2_test.dart

Index: tests/compiler/dart2js_native/subclassing_2_test.dart
diff --git a/tests/compiler/dart2js_native/subclassing_2_test.dart b/tests/compiler/dart2js_native/subclassing_2_test.dart
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+// 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.
+
+import "package:expect/expect.dart";
+import 'dart:_js_helper' show Creates, setNativeSubclassDispatchRecord;
+import 'dart:_interceptors' show findInterceptorForType;
+
+// Test calling convention of methods introduced on subclasses of native
+// classes.
+
+doFoo(r, x) => '$x,${r.oof()}';
+
+class A native "A" {
+  foo(x) => (doFoo)(this, x);
+}
+
+class B extends A {
+  // [oof] is introduced only on this subclass of a native class.  It should
+  // have interceptor calling convention.
+  oof() => 'B';
+}
+
+B makeB() native;
+
+@Creates('=Object')
+getBPrototype() native;
+
+void setup() native r"""
+function A() {}
+function B() {}
+makeA = function(){return new A;};
+makeB = function(){return new B;};
+
+getBPrototype = function(){return B.prototype;};
+""";
+
+main() {
+  setup();
+
+  setNativeSubclassDispatchRecord(getBPrototype(), findInterceptorForType(B));
+
+  B b = makeB();
+  Expect.equals('1,B', b.foo(1));
+}