Revert "Rename mappedBy to map."

tests/corelib/iterable_join_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.
 
 class IC {
   int count = 0;
   String toString() => "${count++}";
 }
 
 testJoin(String expect, Iterable iterable, [String separator]) {
@@ skipping 24 matching lines @@
   testJoin("0,1,2,3", [ic, ic, ic, ic], ",");
 
   var set = new Set()..add(1)..add(2)..add(3);
   var perm = new Set()..add("123")..add("132")..add("213")
                       ..add("231")..add("312")..add("321");
   var setString = set.join();
   Expect.isTrue(perm.contains(setString), "set: $setString");
 
   void testArray(array) {
     testJoin("1,3,5,7,9", array.where((i) => i.isOdd), ",");
-    testJoin("0,2,4,6,8,10,12,14,16,18", array.map((i) => i * 2), ",");
+    testJoin("0,2,4,6,8,10,12,14,16,18", array.mappedBy((i) => i * 2), ",");
     testJoin("5,6,7,8,9", array.skip(5), ",");
     testJoin("5,6,7,8,9", array.skipWhile((i) => i < 5), ",");
     testJoin("0,1,2,3,4", array.take(5), ",");
     testJoin("0,1,2,3,4", array.takeWhile((i) => i < 5), ",");
   }
   testArray([0, 1, 2, 3, 4, 5, 6, 7, 8, 9]);
   var fixedArray = new List.fixedLength(10);
   for (int i = 0; i < 10; i++) {
     fixedArray[i] = i;
   }
   testArray(fixedArray);
   testArray(const [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]);
 }
 
 main() {
   testCollections();
   // TODO(lrn): test scalar lists.
 }