Make getKeys, getValues getters (keys, values).

samples/tests/samples/lib/layout/layout_test.dart

 // Copyright (c) 2011, 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('layout_tests');
 
 #import('dart:html');
 #import('../../../../ui_lib/base/base.dart');
 #import('../../../../ui_lib/layout/layout.dart');
 #import('../../../../ui_lib/view/view.dart');
@@ skipping 150 matching lines @@
     window.setTimeout(expectAsync0(() { grid.removeFromDocument(); }), 0);
   }, 0); 
 }
 
 verifyGrid(String example, [Map expected = null]) {
   printMetrics(example);
   if (expected == null) {
     return;
   }
 
-  for (String name in expected.getKeys()) {
+  for (String name in expected.keys) {
     final values = expected[name];
     final node = document.body.query('#$name');
     Expect.isNotNull(node);
     node.rect.then(expectAsync0((rect) {
       final offset = rect.offset;
       Expect.equals(values[0], offset.left);
       Expect.equals(values[1], offset.top);
       Expect.equals(values[2], offset.width);
       Expect.equals(values[3], offset.height);
     }));
   }
 }
 
 verifyExample(String example, [Map expected = null]) {
   usingGrid(example, (grid) => verifyGrid(example, expected));
 }