Add Iterable.fold (and Stream.fold) which replace `reduce`.

sdk/lib/io/http_impl.dart

 // Copyright (c) 2013, 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.
 
 part of dart.io;
 
 class _HttpIncoming extends Stream<List<int>> {
   final int _transferLength;
   final Completer _dataCompleter = new Completer();
   Stream<List<int>> _stream;
@@ skipping 242 matching lines @@
     return statusCode == HttpStatus.UNAUTHORIZED &&
         challenge != null && challenge.length == 1;
   }
 
   Future<HttpClientResponse> _authenticate() {
     Future<HttpClientResponse> retryWithCredentials(_Credentials cr) {
       if (cr != null) {
         // TODO(sgjesse): Support digest.
         if (cr.scheme == _AuthenticationScheme.BASIC) {
           // Drain body and retry.
-          return reduce(null, (x, y) {}).then((_) {
+          return fold(null, (x, y) {}).then((_) {
               return _httpClient._openUrlFromRequest(_httpRequest.method,
                                                      _httpRequest.uri,
                                                      _httpRequest)
                   .then((request) => request.close());
             });
         }
       }
 
       // Fall through to here to perform normal response handling if
       // there is no sensible authorization handling.
@@ skipping 171 matching lines @@
     }
     _writeHeader();
     _ioSink = new IOSink(new _HttpOutboundConsumer(_ioSink, _consume, asGZip));
     _ioSink.encoding = encoding;
   }
 
   Future _consume(IOSink ioSink, Stream<List<int>> stream, bool asGZip) {
     int contentLength = headers.contentLength;
     if (_ignoreBody) {
       ioSink.close();
-      return stream.reduce(null, (x, y) {}).then((_) => this);
+      return stream.fold(null, (x, y) {}).then((_) => this);
     }
     stream = stream.transform(new _BufferTransformer());
     if (headers.chunkedTransferEncoding) {
       if (asGZip) {
         stream = stream.transform(new ZLibDeflater(gzip: true, level: 6));
       }
       stream = stream.transform(new _ChunkedTransformer());
     } else if (contentLength >= 0) {
       stream = stream.transform(new _ContentLengthValidator(contentLength));
     }
@@ skipping 254 matching lines @@
   HttpConnectionInfo get connectionInfo => _httpClientConnection.connectionInfo;
 
   void _onIncoming(_HttpIncoming incoming) {
     var response = new _HttpClientResponse(incoming,
                                            this,
                                           _httpClient);
     Future<HttpClientResponse> future;
     if (followRedirects && response.isRedirect) {
       if (response.redirects.length < maxRedirects) {
         // Redirect and drain response.
-        future = response.reduce(null, (x, y) {})
+        future = response.fold(null, (x, y) {})
           .then((_) => response.redirect());
       } else {
         // End with exception, too many redirects.
-        future = response.reduce(null, (x, y) {})
+        future = response.fold(null, (x, y) {})
             .then((_) => new Future.immediateError(
                 new RedirectLimitExceededException(response.redirects)));
       }
     } else if (response._shouldAuthenticate) {
       future = response._authenticate();
     } else {
       future = new Future<HttpClientResponse>.immediate(response);
     }
     future.then(
         (v) => _responseCompleter.complete(v),
@@ skipping 337 matching lines @@
   }
 
   Future<HttpClientRequest> postUrl(Uri url) {
     return _openUrl("post", url);
   }
 
   void close({bool force: false}) {
     _closing = true;
     // Create flattened copy of _idleConnections, as 'destory' will manipulate
     // it.
-    var idle = _idleConnections.values.reduce(
+    var idle = _idleConnections.values.fold(
         [],
         (l, e) {
           l.addAll(e);
           return l;
         });
     idle.forEach((e) {
       e.close();
     });
     assert(_idleConnections.isEmpty);
     if (force) {
@@ skipping 131 matching lines @@
           // Continue with next proxy.
           return connect(error.error);
         });
     }
     return connect(new HttpException("No proxies given"));
   }
 
   _Credentials _findCredentials(Uri url, [_AuthenticationScheme scheme]) {
     // Look for credentials.
     _Credentials cr =
-        _credentials.reduce(null, (_Credentials prev, _Credentials value) {
+        _credentials.fold(null, (_Credentials prev, _Credentials value) {
           if (value.applies(url, scheme)) {
             if (prev == null) return value;
             return value.uri.path.length > prev.uri.path.length ? value : prev;
           } else {
             return prev;
           }
         });
     return cr;
   }
 
@@ skipping 515 matching lines @@
 
 
 class _RedirectInfo implements RedirectInfo {
   const _RedirectInfo(int this.statusCode,
                       String this.method,
                       Uri this.location);
   final int statusCode;
   final String method;
   final Uri location;
 }