chrome: Cleanup class/struct forward declarations

chrome/browser/ui/search_engines/keyword_editor_controller.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_SEARCH_ENGINES_KEYWORD_EDITOR_CONTROLLER_H_
 #define CHROME_BROWSER_UI_SEARCH_ENGINES_KEYWORD_EDITOR_CONTROLLER_H_
 
 #include <memory>
 #include <string>
 
 #include "base/macros.h"
 #include "base/strings/string16.h"
 
-class PrefRegistrySimple;
 class Profile;
 class TemplateURL;
 class TemplateURLService;
 class TemplateURLTableModel;
 
 class KeywordEditorController {
  public:
   explicit KeywordEditorController(Profile* profile);
   ~KeywordEditorController();
 
@@ skipping 43 matching lines @@
  private:
   TemplateURLService* url_model_;
 
   // Model for the TableView.
   std::unique_ptr<TemplateURLTableModel> table_model_;
 
   DISALLOW_COPY_AND_ASSIGN(KeywordEditorController);
 };
 
 #endif  // CHROME_BROWSER_UI_SEARCH_ENGINES_KEYWORD_EDITOR_CONTROLLER_H_