NTP: Allow hiding tips and bookmark sync....

chrome/browser/dom_ui/new_tab_ui.h

 // Copyright (c) 2006-2008 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_DOM_UI_NEW_TAB_UI_H_
 #define CHROME_BROWSER_DOM_UI_NEW_TAB_UI_H_
 
 #include <string>
 
 #include "chrome/browser/dom_ui/dom_ui.h"
 #include "chrome/browser/dom_ui/chrome_url_data_manager.h"
 #include "chrome/common/notification_registrar.h"
+#include "testing/gtest/include/gtest/gtest_prod.h"
 
 class GURL;
 class MessageLoop;
 class PrefService;
 class Profile;
 
 // The TabContents used for the New Tab page.
 class NewTabUI : public DOMUI,
                  public NotificationObserver {
  public:
   explicit NewTabUI(TabContents* manager);
   ~NewTabUI();
 
   // Override DOMUI methods so we can hook up the paint timer to the render
   // view host.
   virtual void RenderViewCreated(RenderViewHost* render_view_host);
   virtual void RenderViewReused(RenderViewHost* render_view_host);
 
   static void RegisterUserPrefs(PrefService* prefs);
+  static void MigrateUserPrefs(PrefService* prefs, int old_pref_version,
+                               int new_pref_version);
 
   // Whether we should disable the web resources backend service
   static bool WebResourcesEnabled();
 
   // Whether we should disable the first run notification based on the command
   // line switch.
   static bool FirstRunDisabled();
 
   // Adds "url", "title", and "direction" keys on incoming dictionary, setting
   // title as the url as a fallback on empty title.
   static void SetURLTitleAndDirection(DictionaryValue* dictionary,
                                       const string16& title,
                                       const GURL& gurl);
 
+  // The current preference version.
+  static const int current_pref_version() { return current_pref_version_; }
+
   class NewTabHTMLSource : public ChromeURLDataManager::DataSource {
    public:
     explicit NewTabHTMLSource(Profile* profile);
 
     // Called when the network layer has requested a resource underneath
     // the path we registered.
     virtual void StartDataRequest(const std::string& path, int request_id);
 
     virtual std::string GetMimeType(const std::string&) const {
       return "text/html";
@@ skipping 39 matching lines @@
     // Whether this is the first run.
     static bool first_run_;
 
     // The user's profile.
     Profile* profile_;
 
     DISALLOW_COPY_AND_ASSIGN(NewTabHTMLSource);
   };
 
  private:
+  FRIEND_TEST(NewTabUITest, UpdateUserPrefsVersion);
+
   void Observe(NotificationType type,
                const NotificationSource& source,
                const NotificationDetails& details);
 
   // Reset the CSS caches.
   void InitializeCSSCaches();
 
+  // Updates the user prefs version and calls |MigrateUserPrefs| if needed.
+  // Returns true if the version was updated.
+  static bool UpdateUserPrefsVersion(PrefService* prefs);
+
   NotificationRegistrar registrar_;
 
   // The message id that should be displayed in this NewTabUIContents
   // instance's motd area.
   int motd_message_id_;
 
   // Whether the user is in incognito mode or not, used to determine
   // what HTML to load.
   bool incognito_;
 
+  // The preference version. This used for migrating prefs of the NTP.
+  static const int current_pref_version_ = 1;
+
   DISALLOW_COPY_AND_ASSIGN(NewTabUI);
 };
 
 #endif  // CHROME_BROWSER_DOM_UI_NEW_TAB_UI_H_