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

chrome/test/perf/perf_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 "chrome/test/perf/perf_test.h"
 
 #include <stdio.h>
 
 #include "base/logging.h"
-#include "base/stringprintf.h"
 #include "base/strings/string_number_conversions.h"
+#include "base/strings/stringprintf.h"
 #include "chrome/test/base/chrome_process_util.h"
 
 namespace {
 
 std::string ResultsToString(const std::string& measurement,
                             const std::string& modifier,
                             const std::string& trace,
                             const std::string& values,
                             const std::string& prefix,
                             const std::string& suffix,
@@ skipping 552 matching lines @@
                "commit_charge",
                std::string(),
                "cc" + trace_name,
                charge,
                "kb",
                important);
   return output;
 }
 
 }  // namespace perf_test