By default use current code page on Windows for decoding string

sdk/lib/_internal/compiler/implementation/lib/io_patch.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.
 
 patch class _BufferUtils {
   patch static bool _isBuiltinList(List buffer) {
     throw new UnsupportedError("_isBuiltinList");
   }
 }
 
@@ skipping 174 matching lines @@
 }
 
 patch class _StdIOUtils {
   patch static _getStdioHandle(Socket socket, int num) {
     throw new UnsupportedError("StdIOUtils._getStdioHandle");
   }
   patch static _getStdioHandleType(int num) {
     throw new UnsupportedError("StdIOUtils._getStdioHandleType");
   }
 }
+
+patch class _WindowsCodePageDecoder {
+  patch static String _decodeBytes(List<int> bytes) {
+    throw new UnsupportedError("_WindowsCodePageDecoder._decodeBytes");
+  }
+}
+
+patch class _WindowsCodePageEncoder {
+  patch static List<int> _encodeString(String string) {
+    throw new UnsupportedError("_WindowsCodePageEncoder._encodeString");
+  }
+}