Use a direct include of strings headers in chrome/test/.

chrome/test/perf/url_fetch_test.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/command_line.h"
 #include "base/file_util.h"
 #include "base/files/file_path.h"
 #include "base/path_service.h"
-#include "base/string_util.h"
-#include "base/stringprintf.h"
 #include "base/strings/string_number_conversions.h"
+#include "base/strings/string_util.h"
+#include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/test/test_timeouts.h"
 #include "chrome/common/chrome_paths.h"
 #include "chrome/test/automation/tab_proxy.h"
 #include "chrome/test/ui/ui_perf_test.h"
 
 namespace {
 
 // Provides a UI Test that lets us take the browser to a url, and
 // wait for a cookie value to be set or a JavaScript expression to evaluate
@@ skipping 153 matching lines @@
   // Write out the JS Variable if requested
   base::FilePath jsvar_output_path =
       cmd_line->GetSwitchValuePath("jsvar_output");
   if (!jsvar_output_path.value().empty()) {
     ASSERT_TRUE(WriteValueToFile(result.javascript_variable,
                                  jsvar_output_path));
   }
 }
 
 }  // namespace