Remove deprecated StringBuffer.add, addAll and addCharCode.

sdk/lib/io/websocket_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;
 
 const String _webSocketGUID = "258EAFA5-E914-47DA-95CA-C5AB0DC85B11";
 
 class _WebSocketMessageType {
   static const int NONE = 0;
@@ skipping 168 matching lines @@
 
               if (_remainingPayloadBytes == 0) {
                 _controlFrameEnd(sink);
               }
             } else {
               switch (_currentMessageType) {
                 case _WebSocketMessageType.NONE:
                   throw new WebSocketException("Protocol error");
 
                 case _WebSocketMessageType.TEXT:
-                  _buffer.add(_decodeString(buffer.getRange(index, payload)));
+                  _buffer.write(_decodeString(buffer.getRange(index, payload)));
                   index += payload;
                   if (_remainingPayloadBytes == 0) {
                     _messageFrameEnd(sink);
                   }
                   break;
 
                 case _WebSocketMessageType.BINARY:
-                  _buffer.add(buffer.getRange(index, payload));
+                  _buffer.write(buffer.getRange(index, payload));
                   index += payload;
                   if (_remainingPayloadBytes == 0) {
                     _messageFrameEnd(sink);
                   }
                   break;
 
                 default:
                   throw new WebSocketException("Protocol error");
               }
             }
@@ skipping 455 matching lines @@
       if (data != null) {
         _socket.add(data);
       }
     } catch (_) {
       // The socket can be closed before _socket.done have a chance
       // to complete.
       _writeClosed = true;
     }
   }
 }