Remove _BufferList from dart:io and now use BytesBuilder.

sdk/lib/io/http_body_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 _HttpBodyHandlerTransformer
     extends StreamEventTransformer<HttpRequest, HttpRequestBody> {
   final Encoding _defaultEncoding;
   _HttpBodyHandlerTransformer(this._defaultEncoding);
@@ skipping 26 matching lines @@
         .then((body) => new _HttpClientResponseBody(response, body));
   }
 
   static Future<HttpBody> process(Stream<List<int>> stream,
                                   HttpHeaders headers,
                                   Encoding defaultEncoding) {
     ContentType contentType = headers.contentType;
 
     Future<HttpBody> asBinary() {
       return stream
-          .fold(new _BufferList(), (buffer, data) => buffer..add(data))
-          .then((buffer) => new _HttpBody(contentType,
-                                          "binary",
-                                          buffer.readBytes()));
+          .fold(new BytesBuilder(), (builder, data) => builder..add(data))
+          .then((builder) => new _HttpBody(contentType,
+                                           "binary",
+                                           builder.takeBytes()));
     }
 
     Future<HttpBody> asText(Encoding defaultEncoding) {
       var encoding;
       var charset = contentType.charset;
       if (charset != null) encoding = Encoding.fromName(charset);
       if (encoding == null) encoding = defaultEncoding;
       return stream
           .transform(new StringDecoder(encoding))
           .fold(new StringBuffer(), (buffer, data) => buffer..write(data))
           .then((buffer) => new _HttpBody(contentType,
                                           "text",
                                           buffer.toString()));
     }
 
     Future<HttpBody> asFormData() {
       return stream
           .transform(new MimeMultipartTransformer(
                 contentType.parameters['boundary']))
           .map((HttpMultipartFormData.parse))
           .map((multipart) {
             var future;
             if (multipart.isText) {
               future = multipart
                   .fold(new StringBuffer(), (b, s) => b..write(s))
                   .then((b) => b.toString());
             } else {
               future = multipart
-                  .fold(new _BufferList(), (b, d) => b..add(d))
-                  .then((b) => b.readBytes());
+                  .fold(new BytesBuilder(), (b, d) => b..add(d))
+                  .then((b) => b.takeBytes());
             }
             return future.then((data) {
               var filename =
                   multipart.contentDisposition.parameters['filename'];
               if (filename != null) {
                 data = new _HttpBodyFileUpload(multipart.contentType,
                                                filename,
                                                data);
               }
               return [multipart.contentDisposition.parameters['name'], data];
@@ skipping 99 matching lines @@
   _HttpClientResponseBody(HttpClientResponse response, HttpBody body)
       : super(body.contentType, body.type, body.body),
         this.response = response;
 
   int get statusCode => response.statusCode;
 
   String get reasonPhrase => response.reasonPhrase;
 
   HttpHeaders get headers => response.headers;
 }