Porting refactoring changes:...

base/rand_util_posix.cc

+// Copyright (c) 2008 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/rand_util.h"
+
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#include "base/logging.h"
+
+namespace base {
+
+uint64 RandUInt64() {
+  uint64 number;
+
+  int urandom_fd = open("/dev/urandom", O_RDONLY);
+  CHECK(urandom_fd >= 0);
+  ssize_t bytes_read = read(urandom_fd, &number, sizeof(number));
+  CHECK(bytes_read == sizeof(number));
+  close(urandom_fd);
+
+  return number;
+}
+
+}  // namespace base