Implement the invoke methods (invoke, getField, setField, newInstance, apply) as internal natives.

tests/lib/mirrors/constructors_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.
 
 library test.constructors_test;
 
 import 'dart:mirrors';
 
 import 'package:expect/expect.dart';
 
 import 'stringify.dart';
 
 class Foo {
 }
 
 class Bar {
   Bar();
 }
 
 class Baz {
   Baz.named();
 }
 
 class Biz {
   Biz();
   Biz.named();
 }
 
+class Buz {
+  var x;
+  Buz.generative(this.x);
+  Buz.redirecting(y) : this.generative(y*2);
+  factory Buz.faktory(y) => "Buz $y";
+  factory Buz.redirectingFactory(y) = Buz.faktory;
+}
+
 main() {
   MirrorSystem mirrors = currentMirrorSystem();
   ClassMirror fooMirror = reflectClass(Foo);
   Map<Symbol, MethodMirror> fooConstructors = fooMirror.constructors;
   ClassMirror barMirror = reflectClass(Bar);
   Map<Symbol, MethodMirror> barConstructors = barMirror.constructors;
   ClassMirror bazMirror = reflectClass(Baz);
   Map<Symbol, MethodMirror> bazConstructors = bazMirror.constructors;
   ClassMirror bizMirror = reflectClass(Biz);
   Map<Symbol, MethodMirror> bizConstructors = bizMirror.constructors;
@@ skipping 16 matching lines @@
 
   expect('[s()]',
          fooConstructors.values.map((m) => m.constructorName).toList());
   expect('[s()]',
          barConstructors.values.map((m) => m.constructorName).toList());
   expect('[s(named)]',
          bazConstructors.values.map((m) => m.constructorName).toList());
   expect('[s(), s(named)]',
          bizConstructors.values.map((m) => m.constructorName).toList()
              ..sort(compareSymbols));
+
+  ClassMirror buzMirror = reflectClass(Buz);
+  Expect.equals(7,
+                buzMirror.newInstance(const Symbol('generative'),
+                                      [7]).reflectee.x);
+  Expect.equals(14,
+                buzMirror.newInstance(const Symbol('redirecting'),
+                                      [7]).reflectee.x);
+  Expect.equals('Buz 7',
+                buzMirror.newInstance(const Symbol('faktory'),
+                                      [7]).reflectee);
+  Expect.equals('Buz 7',
+                buzMirror.newInstance(const Symbol('redirectingFactory'),
+                                      [7]).reflectee);
 }