Fix getField/setField optimization for private members.

tests/lib/mirrors/hot_get_field_test.dart

Index: tests/lib/mirrors/hot_get_field_test.dart
diff --git a/tests/lib/mirrors/hot_get_field_test.dart b/tests/lib/mirrors/hot_get_field_test.dart
new file mode 100644
index 0000000000000000000000000000000000000000..ca798d377addca8cc8cfd693843a53d7825dad2e
--- /dev/null
+++ b/tests/lib/mirrors/hot_get_field_test.dart
@@ -0,0 +1,51 @@
+// Copyright (c) 2014, 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.hot_get_field;
+
+import 'dart:mirrors';
+import 'package:expect/expect.dart';
+
+class C {
+  var field;
+  var _field;
+}
+
+const int optimizationThreshold = 20;
+
+testPublic() {
+  var c = new C();
+  var im = reflect(c);
+
+  for (int i = 0; i < (2 * optimizationThreshold); i++) {
+    c.field = i;
+    Expect.equals(i, im.getField(#field).reflectee);
+  }
+}
+
+testPrivate() {
+  var c = new C();
+  var im = reflect(c);
+
+  for (int i = 0; i < (2 * optimizationThreshold); i++) {
+    c._field = i;
+    Expect.equals(i, im.getField(#_field).reflectee);
+  }
+}
+
+testPrivateWrongLibrary() {
+  var c = new C();
+  var im = reflect(c);
+  var selector = MirrorSystem.getSymbol('_field', reflectClass(Mirror).owner);
+
+  for (int i = 0; i < (2 * optimizationThreshold); i++) {
+    Expect.throws(() => im.getField(selector), (e) => e is NoSuchMethodError);
+  }
+}
+
+main() {
+  testPublic();
+  testPrivate();
+  testPrivateWrongLibrary();
+}