Fix File truncate on Windows.

runtime/bin/file_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 "bin/file.h"
 
 #include <fcntl.h>  // NOLINT
@@ skipping 68 matching lines @@
 
 
 bool File::SetPosition(off64_t position) {
   ASSERT(handle_->fd() >= 0);
   return _lseeki64(handle_->fd(), position, SEEK_SET) >= 0;
 }
 
 
 bool File::Truncate(off64_t length) {
   ASSERT(handle_->fd() >= 0);
-  return (_chsize_s(handle_->fd(), length) != -1);
+  return _chsize_s(handle_->fd(), length) == 0;
 }
 
 
 bool File::Flush() {
   ASSERT(handle_->fd());
   return _commit(handle_->fd()) != -1;
 }
 
 
 off64_t File::Length() {
@@ skipping 506 matching lines @@
     return kIdentical;
   } else {
     return kDifferent;
   }
 }
 
 }  // namespace bin
 }  // namespace dart
 
 #endif  // defined(TARGET_OS_WINDOWS)