Remove duplicated code on Windows

runtime/bin/utils_win.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 "platform/globals.h"
 #if defined(TARGET_OS_WINDOWS)
 
 #include <errno.h>  // NOLINT
 #include <time.h>  // NOLINT
 
 #include "bin/utils.h"
+#include "bin/utils_win.h"
 #include "bin/log.h"
 
 
 namespace dart {
 namespace bin {
 
-static void FormatMessageIntoBuffer(DWORD code,
-                                    wchar_t* buffer,
-                                    int buffer_length) {
+void FormatMessageIntoBuffer(DWORD code, wchar_t* buffer, int buffer_length) {
   DWORD message_size =
       FormatMessageW(FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS,
                      NULL,
                      code,
                      MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
                      buffer,
                      buffer_length,
                      NULL);
   if (message_size == 0) {
     if (GetLastError() != ERROR_INSUFFICIENT_BUFFER) {
-      Log::PrintErr("FormatMessage failed %d\n", GetLastError());
+      Log::PrintErr("FormatMessage failed for error code %d (error %d)\n",
+                    code,
+                    GetLastError());
     }
     _snwprintf(buffer, buffer_length, L"OS Error %d", code);
   }
-  buffer[buffer_length - 1] = '\0';
+  // Ensure string termination.
+  buffer[buffer_length - 1] = 0;
 }
 
 
 OSError::OSError() : sub_system_(kSystem), code_(0), message_(NULL) {
   set_code(GetLastError());
 
   static const int kMaxMessageLength = 256;
   wchar_t message[kMaxMessageLength];
   FormatMessageIntoBuffer(code_, message, kMaxMessageLength);
   char* utf8 = StringUtils::WideToUtf8(message);
@@ skipping 100 matching lines @@
 }
 
 void TimerUtils::Sleep(int64_t millis) {
   ::Sleep(millis);
 }
 
 }  // namespace bin
 }  // namespace dart
 
 #endif  // defined(TARGET_OS_WINDOWS)