Bring in latest dart:io WebSocket code.

lib/src/copy/bytes_builder.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.
 
 // This is a copy of "dart:io"'s BytesBuilder implementation, from
 // sdk/lib/io/bytes_builder.dart. It's copied here to make it available to
 // non-"dart:io" applications (issue 18348).
 //
 // Because it's copied directly, there are no modifications from the original.
-library http_parser.bytes_builder;
+//
+// This is up-to-date as of sdk revision
+// 86227840d75d974feb238f8b3c59c038b99c05cf.
+library http_parser.copy.bytes_builder;
 
 import 'dart:math';
 import 'dart:typed_data';
 
 /**
  * Builds a list of bytes, allowing bytes and lists of bytes to be added at the
  * end.
  *
  * Used to efficiently collect bytes and lists of bytes.
  */
@@ skipping 58 matching lines @@
    * Returns `true` if the buffer is not empty.
    */
   bool get isNotEmpty;
 
   /**
    * Clear the contents of the builder.
    */
   void clear();
 }
 
+
 class _CopyingBytesBuilder implements BytesBuilder {
   // Start with 1024 bytes.
   static const int _INIT_SIZE = 1024;
 
   int _length = 0;
   Uint8List _buffer;
 
   void add(List<int> bytes) {
     int bytesLength = bytes.length;
     if (bytesLength == 0) return;
@@ skipping 51 matching lines @@
     --x;
     x |= x >> 1;
     x |= x >> 2;
     x |= x >> 4;
     x |= x >> 8;
     x |= x >> 16;
     return x + 1;
   }
 }
 
+
 class _BytesBuilder implements BytesBuilder {
   int _length = 0;
   final List _chunks = [];
 
   void add(List<int> bytes) {
     if (bytes is! Uint8List) {
       bytes = new Uint8List.fromList(bytes);
     }
     _chunks.add(bytes);
     _length += bytes.length;
@@ skipping 33 matching lines @@
 
   bool get isEmpty => _length == 0;
 
   bool get isNotEmpty => _length != 0;
 
   void clear() {
     _length = 0;
     _chunks.clear();
   }
 }