Move WriteFile and WriteFileDescriptor from file_util to base namespace.

chrome/browser/chromeos/system/automatic_reboot_manager.cc

Index: chrome/browser/chromeos/system/automatic_reboot_manager.cc
diff --git a/chrome/browser/chromeos/system/automatic_reboot_manager.cc b/chrome/browser/chromeos/system/automatic_reboot_manager.cc
index 5ac91e7aaf066fd961e192ce62d6e4efe7c88614..1e00316530cd5a237536a8e183e7849a8a7d215b 100644
--- a/chrome/browser/chromeos/system/automatic_reboot_manager.cc
+++ b/chrome/browser/chromeos/system/automatic_reboot_manager.cc
@@ -117,9 +117,8 @@ void SaveUpdateRebootNeededUptime() {
 
   std::string update_reboot_needed_uptime =
       base::DoubleToString(uptime.InSecondsF());
-  file_util::WriteFileDescriptor(fd,
-                                 update_reboot_needed_uptime.c_str(),
-                                 update_reboot_needed_uptime.size());
+  base::WriteFileDescriptor(fd, update_reboot_needed_uptime.c_str(),
+                            update_reboot_needed_uptime.size());
 }
 
 }  // namespace