Make getKeys, getValues getters (keys, values).

utils/tests/pub/version_solver_test.dart

 // Copyright (c) 2012, 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 pub_update_test;
 
 import 'dart:io';
 import 'dart:isolate';
 
 import '../../pub/lock_file.dart';
@@ skipping 431 matching lines @@
 class MockSource extends Source {
   final Map<String, Map<Version, Package>> _packages;
 
   final String name;
   bool get shouldCache => true;
 
   MockSource(this.name)
       : _packages = <String, Map<Version, Package>>{};
 
   Future<List<Version>> getVersions(String name, String description) {
-    return fakeAsync(() => _packages[description].getKeys());
+    return fakeAsync(() => _packages[description].keys);
   }
 
   Future<Pubspec> describe(PackageId id) {
     return fakeAsync(() {
       return _packages[id.name][id.version].pubspec;
     });
   }
 
   Future<bool> install(PackageId id, String path) {
     throw 'no';
@@ skipping 61 matching lines @@
   var match = new RegExp(r"(.*) from (.*)").firstMatch(name);
   if (match == null) return new Pair<String, Source>(name, source1);
   switch (match[2]) {
   case 'mock1': return new Pair<String, Source>(match[1], source1);
   case 'mock2': return new Pair<String, Source>(match[1], source2);
   case 'root': return new Pair<String, Source>(match[1], rootSource);
   case 'versionless':
     return new Pair<String, Source>(match[1], versionlessSource);
   }
 }