Support for extending native classes

tests/compiler/dart2js_native/subclassing_1_test.dart

+// 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 that subclasses of native classes can be defined by setting the dispatch
+// record.
+
+class A native "A" {
+  foo(x) =>  '$x,${this.oof()}';
+  oof() => 'A';
+}
+
+class B extends A {
+  oof() => 'B';
+}
+
+B makeB1() native;
+B makeB2() native;
+B makeC() native;
+
+@Creates('=Object')
+getBPrototype() native;
+
+@Creates('=Object')
+getCPrototype() native;
+
+void setup() native r"""
+function A() {}
+function B() {}
+function C() {}
+makeA = function(){return new A;};
+makeB1 = function(){return new B;};
+makeB2 = function(){return new B;};
+makeC = function(){return new C;};
+
+getBPrototype = function(){return B.prototype;};
+getCPrototype = function(){return C.prototype;};
+""";
+
+main() {
+  setup();
+
+  setNativeSubclassDispatchRecord(getBPrototype(), findInterceptorForType(B));
+  setNativeSubclassDispatchRecord(getCPrototype(), findInterceptorForType(B));
+
+  B b1 = makeB1();
+  Expect.equals('1,B', b1.foo(1));
+
+  B b2 = makeB2();
+  Expect.equals('2,B', b2.foo(2));
+
+  B b3 = makeC();
+  Expect.equals('3,B', b3.foo(3));
+}