Allow POSIX callers to specify a new file's mode.

base/files/file_util_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_util.h"
 
 #include <dirent.h>
 #include <errno.h>
 #include <fcntl.h>
 #include <libgen.h>
@@ skipping 659 matching lines @@
   if (fd < 0)
     return -1;
 
   ssize_t bytes_read = HANDLE_EINTR(read(fd, data, max_size));
   if (IGNORE_EINTR(close(fd)) < 0)
     return -1;
   return bytes_read;
 }
 
 int WriteFile(const FilePath& filename, const char* data, int size) {
+  return WriteFileMode(filename, data, size, 0640);
+}
+
+int WriteFileMode(const FilePath& filename, const char* data, int size,
+                  mode_t mode) {
   ThreadRestrictions::AssertIOAllowed();
-  int fd = HANDLE_EINTR(creat(filename.value().c_str(), 0640));
+  int fd = HANDLE_EINTR(creat(filename.value().c_str(), mode));
   if (fd < 0)
     return -1;
 
   int bytes_written = WriteFileDescriptor(fd, data, size) ? size : -1;
   if (IGNORE_EINTR(close(fd)) < 0)
     return -1;
   return bytes_written;
 }
 
 bool WriteFileDescriptor(const int fd, const char* data, int size) {
@@ skipping 222 matching lines @@
     result = false;
   if (IGNORE_EINTR(close(outfile)) < 0)
     result = false;
 
   return result;
 }
 #endif  // !defined(OS_MACOSX)
 
 }  // namespace internal
 }  // namespace base