ntp: remove ShownSectionHandler and all references to it

chrome/browser/ui/webui/ntp/shown_sections_handler.h

-// 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.
-
-#ifndef CHROME_BROWSER_UI_WEBUI_NTP_SHOWN_SECTIONS_HANDLER_H_
-#define CHROME_BROWSER_UI_WEBUI_NTP_SHOWN_SECTIONS_HANDLER_H_
-#pragma once
-
-#include "chrome/browser/prefs/pref_change_registrar.h"
-#include "content/browser/webui/web_ui.h"
-#include "content/public/browser/notification_observer.h"
-
-class Extension;
-class PrefService;
-
-namespace base {
-class Value;
-}
-
-// Use for the shown sections bitmask.
-// Currently, only the THUMB and APPS sections can be toggled by the user. Other
-// sections are shown automatically if they have data, and hidden otherwise.
-enum Section {
-  // If one of these is set, the corresponding section shows large thumbnails,
-  // else it shows only a small overview list.
-  THUMB = 1 << 0,
-  APPS = 1 << 6,
-
-  // We use the low 16 bits for sections, the high 16 bits for menu mode.
-  ALL_SECTIONS_MASK = 0x0000FFFF,
-
-  // If one of these is set, then the corresponding section is shown in a menu
-  // at the bottom of the NTP and no data is directly visible on the NTP.
-  MENU_THUMB = 1 << (0 + 16),
-  MENU_RECENT = 1 << (2 + 16),
-  MENU_APPS = 1 << (6 + 16),
-};
-
-class ShownSectionsHandler : public WebUIMessageHandler,
-                             public content::NotificationObserver {
- public:
-  explicit ShownSectionsHandler(PrefService* pref_service);
-  virtual ~ShownSectionsHandler() {}
-
-  // Helper to get the current shown sections.
-  static int GetShownSections(PrefService* pref_service);
-
-  // Expands |section|, collapsing any previously expanded section. This is the
-  // same thing that happens if a user clicks on |section|.
-  static void SetShownSection(PrefService* prefs, Section section);
-
-  // WebUIMessageHandler implementation.
-  virtual void RegisterMessages() OVERRIDE;
-
-  // content::NotificationObserver implementation.
-  virtual void Observe(int type,
-                       const content::NotificationSource& source,
-                       const content::NotificationDetails& details) OVERRIDE;
-
-  // Callback for "setShownSections" message.
-  void HandleSetShownSections(const base::ListValue* args);
-
-  static void RegisterUserPrefs(PrefService* pref_service);
-
-  static void MigrateUserPrefs(PrefService* pref_service,
-                               int old_pref_version,
-                               int new_pref_version);
-
-  static void OnExtensionInstalled(PrefService* prefs,
-                                   const Extension* extension);
-
- private:
-  PrefService* pref_service_;
-  PrefChangeRegistrar pref_registrar_;
-
-  DISALLOW_COPY_AND_ASSIGN(ShownSectionsHandler);
-};
-
-#endif  // CHROME_BROWSER_UI_WEBUI_NTP_SHOWN_SECTIONS_HANDLER_H_