Rename mappedBy to map.

pkg/serialization/test/serialization_test.dart

Index: pkg/serialization/test/serialization_test.dart
diff --git a/pkg/serialization/test/serialization_test.dart b/pkg/serialization/test/serialization_test.dart
index 9279ffa384b1b4061eac3681335582d0a3005254..1662f8aac8ba76bd2b803e53068f4d258144ea47 100644
--- a/pkg/serialization/test/serialization_test.dart
+++ b/pkg/serialization/test/serialization_test.dart
@@ -636,7 +636,7 @@ runRoundTripTestFlat(serializerSetUp) {
 /** 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. */
@@ -648,4 +648,4 @@ class NodeRule extends CustomRule {
     node.parent = state[0];
     node.children = state[2];
   }
-}
+}