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

runtime/bin/io_service_patch.dart

Index: runtime/bin/io_service_patch.dart
diff --git a/runtime/bin/io_service_patch.dart b/runtime/bin/io_service_patch.dart
index 8f46cbfd9683f4ea299d9772ed6038ffd4dba04b..c6a703529cf9fd67fe50451879e337ca6c48ae44 100644
--- a/runtime/bin/io_service_patch.dart
+++ b/runtime/bin/io_service_patch.dart
@@ -2,46 +2,7 @@
 // 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 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 {
+patch class _IOService {
   // Lazy initialize service ports, 32 per isolate.
   static const int _SERVICE_PORT_COUNT = 32;
   static List<SendPort> _servicePort = new List(_SERVICE_PORT_COUNT);
@@ -50,7 +11,7 @@ class IOService {
   static Map<int, Completer> _messageMap = {};
   static int _id = 0;
 
-  static Future dispatch(int request, List data) {
+  /* patch */ static Future dispatch(int request, List data) {
     int id;
     do {
       id = _getNextId();