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

chrome/test/pyautolib/pyautolib.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/base_paths.h"
 #include "base/json/json_writer.h"
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/path_service.h"
-#include "base/string_util.h"
 #include "base/strings/string_number_conversions.h"
+#include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/time.h"
 #include "base/values.h"
 #include "chrome/common/automation_messages.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/test/automation/automation_proxy.h"
 #include "chrome/test/automation/tab_proxy.h"
 #include "chrome/test/pyautolib/pyautolib.h"
 #include "googleurl/src/gurl.h"
 
@@ skipping 132 matching lines @@
         base::StringPrintf("Chrome automation timed out after %d seconds",
                            static_cast<int>(duration.InSeconds())),
         request, true, response);
   } else {
     // TODO(craigdh): Determine specific cause.
     ErrorResponse(
         "Chrome automation failed prior to timing out, did chrome crash?",
         request, false, response);
   }
 }