Cleanup and fixes to some dart:io files

runtime/bin/websocket_impl.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.
 
 const String _webSocketGUID = "258EAFA5-E914-47DA-95CA-C5AB0DC85B11";
 
 class _WebSocketMessageType {
   static const int NONE = 0;
   static const int BINARY = 1;
   static const int TEXT = 2;
@@ skipping 94 matching lines @@
 
             case _WebSocketOpcode.CLOSE:
             case _WebSocketOpcode.PING:
             case _WebSocketOpcode.PONG:
               // Control frames cannot be fragmented.
               if (!_fin) throw new WebSocketException("Protocol error");
               break;
 
             default:
               throw new WebSocketException("Protocol error");
-              break;
             }
             _state = LEN_FIRST;
             break;
 
           case LEN_FIRST:
             _masked = (byte & 0x80) != 0;
             _len = byte & 0x7F;
             if (_isControlFrame() && _len > 126) {
               throw new WebSocketException("Protocol error");
             }
@@ skipping 57 matching lines @@
                 index += payload;
               }
 
               if (_remainingPayloadBytes == 0) {
                 _controlFrameEnd();
               }
             } else {
               switch (_currentMessageType) {
                 case _WebSocketMessageType.NONE:
                   throw new WebSocketException("Protocol error");
-                  break;
 
                 case _WebSocketMessageType.TEXT:
                 case _WebSocketMessageType.BINARY:
                   if (onMessageData !== null) {
                     onMessageData(buffer, index, payload);
                   }
                   index += payload;
                   if (_remainingPayloadBytes == 0) {
                     _messageFrameEnd();
                   }
                   break;
 
                 default:
                   throw new WebSocketException("Protocol error");
-                  break;
-
               }
             }
 
             // Hack - as we always do index++ below.
             index--;
         }
 
         // Move to the next byte.
         index++;
       }
@@ skipping 630 matching lines @@
 
 class _WebSocketCloseEvent implements CloseEvent {
   _WebSocketCloseEvent(this._wasClean, this._code, this._reason);
   bool get wasClean => _wasClean;
   int get code => _code;
   String get reason => _reason;
   bool _wasClean;
   int _code;
   String _reason;
 }