Really fix build after r193020.

chrome/browser/ui/webui/extensions/pack_extension_handler.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/browser/ui/webui/extensions/pack_extension_handler.h"
 
 #include "chrome/browser/extensions/extension_creator.h"
 #include "chrome/browser/ui/chrome_select_file_policy.h"
 #include "base/bind.h"
 #include "base/utf_string_conversions.h"
@@ skipping 171 matching lines @@
   }
 
   load_extension_dialog_ = ui::SelectFileDialog::Create(
       this, new ChromeSelectFilePolicy(web_ui()->GetWebContents()));
   load_extension_dialog_->SelectFile(
       type,
       select_title,
       base::FilePath(),
       &info,
       file_type_index,
-      FILE_PATH_LITERAL(std::string()),
+      base::FilePath::StringType(),
       web_ui()->GetWebContents()->GetView()->GetTopLevelNativeWindow(),
       NULL);
 }
 
 void PackExtensionHandler::ShowAlert(const std::string& message) {
   ListValue arguments;
   arguments.Append(Value::CreateStringValue(message));
   web_ui()->CallJavascriptFunction("PackExtensionOverlay.showError", arguments);
 }