Add some words of caution to File::Flush().

base/files/file_win.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/files/file.h"
 
 #include <io.h>
 #include <stdint.h>
 
 #include "base/logging.h"
@@ skipping 378 matching lines @@
 
     if (flags & (FLAG_OPEN_ALWAYS))
       created_ = (ERROR_ALREADY_EXISTS != GetLastError());
     else if (flags & (FLAG_CREATE_ALWAYS | FLAG_CREATE))
       created_ = true;
   } else {
     error_details_ = OSErrorToFileError(GetLastError());
   }
 }
 
-bool File::DoFlush() {
+bool File::Flush() {
   ThreadRestrictions::AssertIOAllowed();
   DCHECK(IsValid());
+  SCOPED_FILE_TRACE("Flush");
   return ::FlushFileBuffers(file_.Get()) != FALSE;
 }
 
 void File::SetPlatformFile(PlatformFile file) {
   file_.Set(file);
 }
 
 }  // namespace base