Make getKeys, getValues getters (keys, values).

samples/tests/samples/lib/layout/grid_layout_demo.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.
 
 /**
  * An app for testing the grid layout system.
  */
 
 /** Creates a grid view structure given the CSS styles. */
 View createGrid(Map<String, Map<String, String>> styles) {
   final gridStyle = styles['#grid'];
 
   final children = new List<MockView>();
-  for (final String id in styles.getKeys()) {
+  for (final String id in styles.keys) {
     // All selectors in this test are id selectors string the # prefix.
     assert(id.startsWith('#'));
     String elemId = id.substring(1);
     if (elemId != 'grid') {
       children.add(new MockView(elemId, styles[id]));
     }
   }
 
   return new MockCompositeView('grid', gridStyle, children);
 }
 
 void _onLoad() {
   var query = Uri.parseQuery(window.location.search)['q'];
   if (query != null && query.length == 1) {
     query = Uri.decodeComponent(query[0]);
     addGridStyles('100%', '100%', 'margin:0px;');
     final view = createGrid(GridExamples.styles[query]);
     view.addToDocument(document.body);
     _addColorStyles();
     printMetrics(query);
   } else {
     final html = new StringBuffer();
-    for (String ex in GridExamples.styles.getKeys()) {
+    for (String ex in GridExamples.styles.keys) {
       html.add('<div><a href="?q=$ex">Grid Example $ex</a></div>');
     }
     document.body.innerHTML = html.toString();
   }
 }
 
 void addGridStyles(String width, String height, [String margin = '']) {
   // Use monospace font and fixed line-height so the text size is predictable.
   // TODO(jmesserly): only tested on Chromium Mac/Linux
   Dom.addStyle('''
@@ skipping 75 matching lines @@
 }
 
 void _appendMetrics(StringBuffer sb, Element node, ElementRect rect,
     [String indent = '']) {
   String id = node.id;
   final offset = rect.offset;
   num left = offset.left, top = offset.top;
   num width = offset.width, height = offset.height;
   sb.add("${indent}'$id': [$left, $top, $width, $height],\n");
 }