Use a direct include of strings headers in base/.

base/file_util.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/file_util.h"
 
 #if defined(OS_WIN)
 #include <io.h>
 #endif
 #include <stdio.h>
 
 #include <fstream>
 
 #include "base/files/file_enumerator.h"
 #include "base/files/file_path.h"
 #include "base/logging.h"
-#include "base/string_util.h"
-#include "base/stringprintf.h"
 #include "base/strings/string_piece.h"
+#include "base/strings/string_util.h"
+#include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
 
 using base::FileEnumerator;
 using base::FilePath;
 
 namespace {
 
 const FilePath::CharType kExtensionSeparator = FILE_PATH_LITERAL('.');
 
 // The maximum number of 'uniquified' files we will try to create.
@@ skipping 238 matching lines @@
 
 int64 ComputeDirectorySize(const FilePath& root_path) {
   int64 running_size = 0;
   FileEnumerator file_iter(root_path, true, FileEnumerator::FILES);
   while (!file_iter.Next().empty())
     running_size += file_iter.GetInfo().GetSize();
   return running_size;
 }
 
 }  // namespace