Remove _BufferList from dart:io and now use BytesBuilder.

tests/standalone/io/web_socket_protocol_processor_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.
 
 import "package:expect/expect.dart";
 import "dart:utf";
 import "dart:math";
 import "dart:async";
 import "dart:collection";
 import "dart:typed_data";
 import "dart:isolate";
 
 part '../../../sdk/lib/io/common.dart';
 part "../../../sdk/lib/io/http.dart";
-part "../../../sdk/lib/io/buffer_list.dart";
+part "../../../sdk/lib/io/bytes_builder.dart";
 part "../../../sdk/lib/io/io_sink.dart";
 part "../../../sdk/lib/io/string_transformer.dart";
 part "../../../sdk/lib/io/websocket.dart";
 part "../../../sdk/lib/io/websocket_impl.dart";
 
 class WebSocketFrame {
   WebSocketFrame(int opcode, List<int> data);
 }
 
 // Class that when hooked up to the web socket protocol transformer will
@@ skipping 215 matching lines @@
       true, FRAME_OPCODE_BINARY, null, message, 0, message.length);
   controller.add(frame);
 }
 
 
 void main() {
   testFullMessages();
   testFragmentedMessages();
   testUnmaskedMessage();
 }