Improve the encoding/decoding to/from system encoding on Windows

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 386 matching lines @@
         return true;
       }
     }
     i += 1;
     name = main_options[i].option_name;
   }
   return false;
 }
 
 
-// Convert all the arguments to UTF8. On Windows, the arguments are
-// encoded in the current code page and not UTF8.
-//
-// Returns true if the arguments are converted. In that case
-// each of the arguments need to be deallocated using free.
-static bool Utf8ConvertArgv(int argc, char** argv) {
-  int unicode_argc = 0;
-  wchar_t** unicode_argv = ShellUtils::GetUnicodeArgv(&unicode_argc);
-  if (unicode_argv == NULL) return false;
-  for (int i = 0; i < unicode_argc; i++) {
-    wchar_t* arg = unicode_argv[i];
-    argv[i] = StringUtils::WideToUtf8(arg);
-  }
-  ShellUtils::FreeUnicodeArgv(unicode_argv);
-  return true;
-}
-
-
 // Parse out the command line arguments. Returns -1 if the arguments
 // are incorrect, 0 otherwise.
 static int ParseArguments(int argc,
                           char** argv,
                           CommandLineOptions* vm_options,
                           char** script_name,
                           CommandLineOptions* dart_options,
                           bool* print_flags_seen,
                           bool* verbose_debug_seen) {
   const char* kPrefix = "--";
@@ skipping 451 matching lines @@
   bool verbose_debug_seen = false;
 
   vm_options.AddArgument("--no_write_protect_code");
   // Perform platform specific initialization.
   if (!Platform::Initialize()) {
     Log::PrintErr("Initialization failed\n");
   }
 
   // On Windows, the argv strings are code page encoded and not
   // utf8. We need to convert them to utf8.
-  bool argv_converted = Utf8ConvertArgv(argc, argv);
+  bool argv_converted = ShellUtils::GetUtf8Argv(argc, argv);
 
   // Parse command line arguments.
   if (ParseArguments(argc,
                      argv,
                      &vm_options,
                      &script_name,
                      &dart_options,
                      &print_flags_seen,
                      &verbose_debug_seen) < 0) {
     if (has_help_option) {
@@ skipping 195 matching lines @@
   exit(Process::GlobalExitCode());
 }
 
 }  // namespace bin
 }  // namespace dart
 
 int main(int argc, char** argv) {
   dart::bin::main(argc, argv);
   UNREACHABLE();
 }