Reapply "Rename mappedBy to map."

pkg/serialization/test/serialization_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 serialization_test;
 
 import 'dart:json' as json;
 import 'package:unittest/unittest.dart';
 import 'package:serialization/serialization.dart';
 import 'package:serialization/src/serialization_helpers.dart';
@@ skipping 623 matching lines @@
   expect(m2.name, "2");
   expect(m3.name, "3");
   expect(m2.parent, m1);
   expect(m3.parent, m1);
   expect(m1.parent, isNull);
 }
 
 /** Extract the state from [object] using the rules in [s] and return it. */
 states(object, Serialization s) {
   var rules = s.rulesFor(object, null);
-  return rules.mappedBy((x) => x.extractState(object, doNothing)).toList();
+  return rules.map((x) => x.extractState(object, doNothing)).toList();
 }
 
 /** A hard-coded rule for serializing Node instances. */
 class NodeRule extends CustomRule {
   bool appliesTo(instance, _) => instance.runtimeType == Node;
   getState(instance) => [instance.parent, instance.name, instance.children];
   create(state) => new Node(state[1]);
   setState(Node node, state) {
     node.parent = state[0];
     node.children = state[2];
   }
 }