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      1 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #ifndef CHROME_BROWSER_POLICY_MANAGED_PREFS_BANNER_BASE_H_
      6 #define CHROME_BROWSER_POLICY_MANAGED_PREFS_BANNER_BASE_H_
      7 #pragma once
      8 
      9 #include "base/basictypes.h"
     10 #include "base/memory/scoped_ptr.h"
     11 #include "chrome/browser/ui/options/options_window.h"
     12 #include "content/common/notification_observer.h"
     13 
     14 class PrefService;
     15 class PrefSetObserver;
     16 
     17 namespace policy {
     18 
     19 // Common base functionality for the managed prefs warning banner displayed in
     20 // the preference dialogs when there are options that are controlled by
     21 // configuration policy and thus cannot be changed by the user.
     22 class ManagedPrefsBannerBase : public NotificationObserver {
     23  public:
     24   // Initialize the banner with a set of preferences suitable for the given
     25   // options |page|. Subclasses may change that set by calling AddPref() and
     26   // RemovePref() afterwards.
     27   ManagedPrefsBannerBase(PrefService* local_state,
     28                          PrefService* user_prefs,
     29                          OptionsPage page);
     30 
     31   // Convenience constructor that fetches the local state PrefService from the
     32   // global g_browser_process.
     33   ManagedPrefsBannerBase(PrefService* user_prefs, OptionsPage page);
     34 
     35   virtual ~ManagedPrefsBannerBase();
     36 
     37   // Determine whether the banner should be visible.
     38   bool DetermineVisibility() const;
     39 
     40   // Add a local state preference as visibility trigger.
     41   void AddLocalStatePref(const char* pref);
     42   // Remove a local state preference from being a visibility trigger.
     43   void RemoveLocalStatePref(const char* pref);
     44 
     45   // Add a user preference as visibility trigger.
     46   void AddUserPref(const char* pref);
     47   // Remove a user preference from being a visibility trigger.
     48   void RemoveUserPref(const char* pref);
     49 
     50  protected:
     51   // Update banner visibility. This is called whenever a preference change is
     52   // observed that may lead to changed visibility of the banner. Subclasses may
     53   // override this in order to show/hide the banner.
     54   virtual void OnUpdateVisibility() { }
     55 
     56  private:
     57   // Initialization helper, called from the constructors.
     58   void Init(PrefService* local_state,
     59             PrefService* user_prefs,
     60             OptionsPage page);
     61 
     62   // |NotificationObserver| implementation.
     63   virtual void Observe(NotificationType type,
     64                        const NotificationSource& source,
     65                        const NotificationDetails& details);
     66 
     67   scoped_ptr<PrefSetObserver> local_state_set_;
     68   scoped_ptr<PrefSetObserver> user_pref_set_;
     69 
     70   DISALLOW_COPY_AND_ASSIGN(ManagedPrefsBannerBase);
     71 };
     72 
     73 }  // namespace policy
     74 
     75 #endif  // CHROME_BROWSER_POLICY_MANAGED_PREFS_BANNER_BASE_H_
     76