Replace some deprecated usages of readdir_r with readdir

base/files/file_enumerator_posix.cc

 // Copyright (c) 2013 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_enumerator.h"
 
 #include <dirent.h>
 #include <errno.h>
 #include <fnmatch.h>
 #include <stdint.h>
@@ skipping 113 matching lines @@
   DIR* dir = opendir(source.value().c_str());
   if (!dir)
     return false;
 
 #if !defined(OS_LINUX) && !defined(OS_MACOSX) && !defined(OS_BSD) && \
     !defined(OS_SOLARIS) && !defined(OS_ANDROID)
   #error Port warning: depending on the definition of struct dirent, \
          additional space for pathname may be needed
 #endif
 
-  struct dirent dent_buf;
-  struct dirent* dent;
-  while (readdir_r(dir, &dent_buf, &dent) == 0 && dent) {
+  // In all implementations of the C library that Chromium can run with,
+  // concurrent calls to readdir that specify different directory streams are
+  // thread-safe. This is the case here, since the directory stream is scoped to
+  // the current function. See https://codereview.chromium.org/2411833004/#msg3
+  for (struct dirent* dent = readdir(dir); dent; dent = readdir(dir)) {
     FileInfo info;
     info.filename_ = FilePath(dent->d_name);
 
     FilePath full_name = source.Append(dent->d_name);
     int ret;
     if (show_links)
       ret = lstat(full_name.value().c_str(), &info.stat_);
     else
       ret = stat(full_name.value().c_str(), &info.stat_);
     if (ret < 0) {
       // Print the stat() error message unless it was ENOENT and we're
       // following symlinks.
       if (!(errno == ENOENT && !show_links)) {
         DPLOG(ERROR) << "Couldn't stat "
                      << source.Append(dent->d_name).value();
       }
       memset(&info.stat_, 0, sizeof(info.stat_));
     }
     entries->push_back(info);
   }
 
   closedir(dir);
   return true;
 }
 
 }  // namespace base