dart:io | Implement asynchronous versions of FileSystemEntity methods.

sdk/lib/_internal/compiler/implementation/lib/io_patch.dart

Index: sdk/lib/_internal/compiler/implementation/lib/io_patch.dart
diff --git a/sdk/lib/_internal/compiler/implementation/lib/io_patch.dart b/sdk/lib/_internal/compiler/implementation/lib/io_patch.dart
index fab0cf59f4e7fa236e22691613e7538ace770afb..a31da5738fe96537e69b873c6284d248dc083b67 100644
--- a/sdk/lib/_internal/compiler/implementation/lib/io_patch.dart
+++ b/sdk/lib/_internal/compiler/implementation/lib/io_patch.dart
@@ -57,10 +57,10 @@ patch class _FileUtils {
 }
 
 patch class FileSystemEntity {
-  patch static int _getType(String path, bool followLinks) {
+  patch static _getType(String path, bool followLinks) {
     throw new UnsupportedError("FileSystemEntity._getType");
   }
-  patch static bool _identical(String path1, String path2) {
+  patch static _identical(String path1, String path2) {
     throw new UnsupportedError("FileSystemEntity._identical");
   }
 }