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

tests/lib/mirrors/constructors_test.dart

Index: tests/lib/mirrors/constructors_test.dart
===================================================================
--- tests/lib/mirrors/constructors_test.dart	(revision 24825)
+++ tests/lib/mirrors/constructors_test.dart	(working copy)
@@ -26,6 +26,14 @@
   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);
@@ -62,4 +70,18 @@
   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);
 }