Add settings:: namespace to MdSettingsUi.

chrome/browser/ui/webui/settings/md_settings_ui.h

 // 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.
 
-#ifndef CHROME_BROWSER_UI_WEBUI_MD_SETTINGS_UI_H_
-#define CHROME_BROWSER_UI_WEBUI_MD_SETTINGS_UI_H_
+#ifndef CHROME_BROWSER_UI_WEBUI_SETTINGS_MD_SETTINGS_UI_H_
+#define CHROME_BROWSER_UI_WEBUI_SETTINGS_MD_SETTINGS_UI_H_
 
 #include "chrome/browser/ui/webui/options/core_options_handler.h"
 #include "chrome/browser/ui/webui/options/options_ui.h"
 #include "content/public/browser/web_ui_controller.h"
 
 // The WebUI handler for chrome://md-settings.
 class MdSettingsUI : public content::WebUIController,
                      public options::OptionsPageUIHandlerHost {
  public:
   explicit MdSettingsUI(content::WebUI* web_ui);
   ~MdSettingsUI() override;
 
   // OptionsPageUIHandlerHost:
   void InitializeHandlers() override;
 
  private:
   options::CoreOptionsHandler* core_handler_;
 
   DISALLOW_COPY_AND_ASSIGN(MdSettingsUI);
 };
 
-#endif  // CHROME_BROWSER_UI_WEBUI_MD_SETTINGS_UI_H_
+#endif  // CHROME_BROWSER_UI_WEBUI_SETTINGS_MD_SETTINGS_UI_H_