Add error handling to random access file

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 "bin/file.h"
 
 #include <fcntl.h>
 #include <io.h>
 #include <stdio.h>
 #include <string.h>
@@ skipping 64 matching lines @@
   return (lseek(handle_->fd(), position, SEEK_SET) != -1);
 }
 
 
 bool File::Truncate(int64_t length) {
   ASSERT(handle_->fd() >= 0);
   return (chsize(handle_->fd(), length) != -1);
 }
 
 
-void File::Flush() {
+bool File::Flush() {
   ASSERT(handle_->fd());
-  _commit(handle_->fd());
+  return _commit(handle_->fd()) != -1;
 }
 
 
 off_t File::Length() {
   ASSERT(handle_->fd() >= 0);
   off_t position = lseek(handle_->fd(), 0, SEEK_CUR);
   if (position < 0) {
     // The file is not capable of seeking. Return an error.
     return -1;
   }
@@ skipping 114 matching lines @@
 const char* File::StringEscapedPathSeparator() {
   return "\\\\";
 }
 
 
 File::StdioHandleType File::GetStdioHandleType(int fd) {
   // Treat all stdio handles as pipes. The Windows event handler and
   // socket code will handle the different handle types.
   return kPipe;
 }