Add more dart:io related precompilation roots.

runtime/bin/main.cc

 // 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.
 
 #include <stdlib.h>
 #include <string.h>
 #include <stdio.h>
 
 #include "include/dart_api.h"
 #include "include/dart_tools_api.h"
@@ skipping 1227 matching lines @@
         { "dart:_builtin", "::", "_setWorkingDirectory" },
         { "dart:_builtin", "::", "_setPackageRoot" },
         { "dart:_builtin", "::", "_addPackageMapEntry" },
         { "dart:_builtin", "::", "_loadPackagesMap" },
         { "dart:_builtin", "::", "_loadDataAsync" },
         { "dart:io", "::", "_makeUint8ListView" },
         { "dart:io", "::", "_makeDatagram" },
         { "dart:io", "::", "_setupHooks" },
         { "dart:io", "::", "_getWatchSignalInternal" },
         { "dart:io", "CertificateException", "CertificateException." },
+        { "dart:io", "Directory", "Directory." },
+        { "dart:io", "File", "File." },
+        { "dart:io", "FileSystemException", "FileSystemException." },
         { "dart:io", "HandshakeException", "HandshakeException." },
+        { "dart:io", "Link", "Link." },
         { "dart:io", "OSError", "OSError." },
         { "dart:io", "TlsException", "TlsException." },
         { "dart:io", "X509Certificate", "X509Certificate._" },
         { "dart:io", "_ExternalBuffer", "set:data" },
         { "dart:io", "_Platform", "set:_nativeScript" },
         { "dart:io", "_ProcessStartStatus", "set:_errorCode" },
         { "dart:io", "_ProcessStartStatus", "set:_errorMessage" },
         { "dart:io", "_SecureFilterImpl", "get:ENCRYPTED_SIZE" },
         { "dart:io", "_SecureFilterImpl", "get:SIZE" },
         { "dart:vmservice_io", "::", "main" },
@@ skipping 294 matching lines @@
   Platform::Exit(Process::GlobalExitCode());
 }
 
 }  // namespace bin
 }  // namespace dart
 
 int main(int argc, char** argv) {
   dart::bin::main(argc, argv);
   UNREACHABLE();
 }