Use a direct include of strings headers in chromeos/.

chromeos/network/onc/onc_validator.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 "chromeos/network/onc/onc_validator.h"
 
 #include <algorithm>
 #include <string>
 
 #include "base/json/json_writer.h"
 #include "base/logging.h"
-#include "base/string_number_conversions.h"
-#include "base/string_util.h"
+#include "base/strings/string_number_conversions.h"
+#include "base/strings/string_util.h"
 #include "base/values.h"
 #include "chromeos/network/onc/onc_constants.h"
 #include "chromeos/network/onc/onc_signature.h"
 
 namespace chromeos {
 namespace onc {
 
 namespace {
 
 std::string ValueToString(const base::Value& value) {
@@ skipping 753 matching lines @@
 }
 
 std::string Validator::MessageHeader() {
   std::string path = path_.empty() ? "toplevel" : JoinString(path_, ".");
   std::string message = "At " + path + ": ";
   return message;
 }
 
 }  // namespace onc
 }  // namespace chromeos