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

base/files/file_posix.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 <errno.h>
 #include <fcntl.h>
 #include <stdint.h>
 #include <sys/stat.h>
@@ skipping 493 matching lines @@
 
   if (flags & FLAG_DELETE_ON_CLOSE)
     unlink(path.value().c_str());
 
   async_ = ((flags & FLAG_ASYNC) == FLAG_ASYNC);
   error_details_ = FILE_OK;
   file_.reset(descriptor);
 }
 #endif  // !defined(OS_NACL)
 
-bool File::DoFlush() {
+bool File::Flush() {
   ThreadRestrictions::AssertIOAllowed();
   DCHECK(IsValid());
+  SCOPED_FILE_TRACE("Flush");
 
 #if defined(OS_NACL)
   NOTIMPLEMENTED();  // NaCl doesn't implement fsync.
   return true;
 #elif defined(OS_LINUX) || defined(OS_ANDROID)
   return !HANDLE_EINTR(fdatasync(file_.get()));
 #else
   return !HANDLE_EINTR(fsync(file_.get()));
 #endif
 }
 
 void File::SetPlatformFile(PlatformFile file) {
   DCHECK(!file_.is_valid());
   file_.reset(file);
 }
 
 }  // namespace base