Use metadata annotation @patch for patch classes

runtime/bin/stdio_patch.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.
 
-patch class _StdIOUtils {
+@patch class _StdIOUtils {
   static Stdin _getStdioInputStream() {
     switch (_getStdioHandleType(0)) {
       case _STDIO_HANDLE_TYPE_TERMINAL:
       case _STDIO_HANDLE_TYPE_PIPE:
       case _STDIO_HANDLE_TYPE_SOCKET:
         return new Stdin._(new _Socket._readPipe(0));
       case _STDIO_HANDLE_TYPE_FILE:
         return new Stdin._(new _FileStream.forStdin());
       default:
         throw new FileSystemException("Unsupported stdin type");
@@ skipping 23 matching lines @@
     if (result is OSError) {
       throw new FileSystemException(
           "Error retrieving socket type", "", result);
     }
     return result;
   }
 
   static _getStdioHandleType(int fd) native "File_GetStdioHandleType";
 }
 
-patch class Stdin {
-  /* patch */ int readByteSync() native "Stdin_ReadByte";
+@patch class Stdin {
+  /* @patch */ int readByteSync() native "Stdin_ReadByte";
 
-  /* patch */ bool get echoMode => _echoMode;
-  /* patch */ void set echoMode(bool enabled) { _echoMode = enabled; }
+  /* @patch */ bool get echoMode => _echoMode;
+  /* @patch */ void set echoMode(bool enabled) { _echoMode = enabled; }
 
-  /* patch */ bool get lineMode => _lineMode;
-  /* patch */ void set lineMode(bool enabled) { _lineMode = enabled; }
+  /* @patch */ bool get lineMode => _lineMode;
+  /* @patch */ void set lineMode(bool enabled) { _lineMode = enabled; }
 
   static bool get _echoMode native "Stdin_GetEchoMode";
   static void set _echoMode(bool enabled) native "Stdin_SetEchoMode";
   static bool get _lineMode native "Stdin_GetLineMode";
   static void set _lineMode(bool enabled) native "Stdin_SetLineMode";
 }
 
-patch class Stdout {
-  /* patch */ bool _hasTerminal(int fd) {
+@patch class Stdout {
+  /* @patch */ bool _hasTerminal(int fd) {
     try {
       _terminalSize(fd);
       return true;
     } catch (_) {
       return false;
     }
   }
 
-  /* patch */ int _terminalColumns(int fd) => _terminalSize(fd)[0];
-  /* patch */ int _terminalLines(int fd) => _terminalSize(fd)[1];
+  /* @patch */ int _terminalColumns(int fd) => _terminalSize(fd)[0];
+  /* @patch */ int _terminalLines(int fd) => _terminalSize(fd)[1];
 
   static List _terminalSize(int fd) {
     var size = _getTerminalSize(fd);
     if (size is! List) {
       throw new StdoutException("Could not get terminal size", size);
     }
     return size;
   }
 
   static _getTerminalSize(int fd) native "Stdout_GetTerminalSize";
 }
 
 
 _getStdioHandle(_NativeSocket socket, int num) native "Socket_GetStdioHandle";
 _getSocketType(_NativeSocket nativeSocket) native "Socket_GetType";