Revert "Remove deprecated mappedBy."

utils/pub/utils.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.
 
 /// Generic utility functions. Stuff that should possibly be in core.
 library utils;
 
 import 'dart:async';
 import 'dart:crypto';
 import 'dart:isolate';
@@ skipping 256 matching lines @@
       : new StreamController();
   stream.listen(controller.add,
       onError: (e) => controller.signalError(e),
       onDone: controller.close);
   return controller.stream;
 }
 
 /// Like [Iterable.where], but allows [test] to return [Future]s and uses the
 /// results of those [Future]s as the test.
 Future<Iterable> futureWhere(Iterable iter, test(value)) {
-  return Future.wait(iter.map((e) {
+  return Future.wait(iter.mappedBy((e) {
     var result = test(e);
     if (result is! Future) result = new Future.immediate(result);
     return result.then((result) => new Pair(e, result));
   }))
       .then((pairs) => pairs.where((pair) => pair.last))
-      .then((pairs) => pairs.map((pair) => pair.first));
+      .then((pairs) => pairs.mappedBy((pair) => pair.first));
 }
 
 // TODO(nweiz): unify the following functions with the utility functions in
 // pkg/http.
 
 /// Like [String.split], but only splits on the first occurrence of the pattern.
 /// This will always return an array of two elements or fewer.
 List<String> split1(String toSplit, String pattern) {
   if (toSplit.isEmpty) return <String>[];
 
@@ skipping 41 matching lines @@
 
 /// Add all key/value pairs from [source] to [destination], overwriting any
 /// pre-existing values.
 void mapAddAll(Map destination, Map source) =>
   source.forEach((key, value) => destination[key] = value);
 
 /// Decodes a URL-encoded string. Unlike [decodeUriComponent], this includes
 /// replacing `+` with ` `.
 String urlDecode(String encoded) =>
   decodeUriComponent(encoded.replaceAll("+", " "));