Clean up IOService implementation to be shared between patched and non-patched code.

sdk/lib/io/io_service.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 int _FILE_EXISTS = 0;
+const int _FILE_CREATE = 1;
+const int _FILE_DELETE = 2;
+const int _FILE_RENAME = 3;
+const int _FILE_OPEN = 4;
+const int _FILE_RESOLVE_SYMBOLIC_LINKS = 5;
+const int _FILE_CLOSE = 6;
+const int _FILE_POSITION = 7;
+const int _FILE_SET_POSITION = 8;
+const int _FILE_TRUNCATE = 9;
+const int _FILE_LENGTH = 10;
+const int _FILE_LENGTH_FROM_PATH = 11;
+const int _FILE_LAST_MODIFIED = 12;
+const int _FILE_FLUSH = 13;
+const int _FILE_READ_BYTE = 14;
+const int _FILE_WRITE_BYTE = 15;
+const int _FILE_READ = 16;
+const int _FILE_READ_INTO = 17;
+const int _FILE_WRITE_FROM = 18;
+const int _FILE_CREATE_LINK = 19;
+const int _FILE_DELETE_LINK = 20;
+const int _FILE_RENAME_LINK = 21;
+const int _FILE_LINK_TARGET = 22;
+const int _FILE_TYPE = 23;
+const int _FILE_IDENTICAL = 24;
+const int _FILE_STAT = 25;
+const int _SOCKET_LOOKUP = 26;
+const int _SOCKET_LIST_INTERFACES = 27;
+const int _SOCKET_REVERSE_LOOKUP = 28;
+const int _DIRECTORY_CREATE = 29;
+const int _DIRECTORY_DELETE = 30;
+const int _DIRECTORY_EXISTS = 31;
+const int _DIRECTORY_CREATE_TEMP = 32;
+const int _DIRECTORY_LIST_START = 33;
+const int _DIRECTORY_LIST_NEXT = 34;
+const int _DIRECTORY_LIST_STOP = 35;
+const int _DIRECTORY_RENAME = 36;
+const int _SSL_PROCESS_FILTER = 37;
+
+class _IOService {
+  external static Future dispatch(int request, List data);
+}