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

chrome/test/webdriver/commands/log_command.cc

 // Copyright (c) 2011 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/webdriver/commands/log_command.h"
 
-#include "base/string_util.h"
+#include "base/strings/string_util.h"
 #include "base/values.h"
 #include "chrome/test/webdriver/commands/response.h"
 #include "chrome/test/webdriver/webdriver_error.h"
 #include "chrome/test/webdriver/webdriver_session.h"
 
 namespace webdriver {
 
 LogCommand::LogCommand(
     const std::vector<std::string>& path_segments,
     DictionaryValue* parameters)
@@ skipping 22 matching lines @@
 
   if (log_type.type() == LogType::kDriver) {
     response->SetValue(session_->GetLog());
   } else {
     response->SetError(new Error(kUnknownError, "Unrecognized type: " + type));
     return;
   }
 }
 
 }  // namespace webdriver