Move ReadFileToString to the base namespace.

chrome/browser/chromeos/login/screens/update_screen.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 "chrome/browser/chromeos/login/screens/update_screen.h"
 
 #include <algorithm>
 
 #include "base/bind.h"
 #include "base/command_line.h"
@@ skipping 442 matching lines @@
 
 bool UpdateScreen::HasCriticalUpdate() {
   if (is_ignore_update_deadlines_)
     return true;
 
   std::string deadline;
   // Checking for update flag file causes us to do blocking IO on UI thread.
   // Temporarily allow it until we fix http://crosbug.com/11106
   base::ThreadRestrictions::ScopedAllowIO allow_io;
   base::FilePath update_deadline_file_path(kUpdateDeadlineFile);
-  if (!file_util::ReadFileToString(update_deadline_file_path, &deadline) ||
+  if (!base::ReadFileToString(update_deadline_file_path, &deadline) ||
       deadline.empty()) {
     return false;
   }
 
   // TODO(dpolukhin): Analyze file content. Now we can just assume that
   // if the file exists and not empty, there is critical update.
   return true;
 }
 
 void UpdateScreen::OnActorDestroyed(UpdateScreenActor* actor) {
@@ skipping 63 matching lines @@
       GetErrorScreen()->SetErrorState(ErrorScreen::ERROR_STATE_PROXY,
                                       std::string());
       break;
     default:
       NOTREACHED();
       break;
   }
 }
 
 }  // namespace chromeos