Show a different banner in chrome://settings for extension-controlled settings.

chrome/browser/policy/managed_prefs_banner_base.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_POLICY_MANAGED_PREFS_BANNER_BASE_H_
-#define CHROME_BROWSER_POLICY_MANAGED_PREFS_BANNER_BASE_H_
-#pragma once
-
-#include "base/basictypes.h"
-#include "base/memory/scoped_ptr.h"
-#include "chrome/browser/ui/options/options_util.h"
-#include "content/common/notification_observer.h"
-
-class PrefService;
-class PrefSetObserver;
-
-namespace policy {
-
-// Common base functionality for the managed prefs warning banner displayed in
-// the preference dialogs when there are options that are controlled by
-// configuration policy and thus cannot be changed by the user.
-class ManagedPrefsBannerBase : public NotificationObserver {
- public:
-  // Initialize the banner with a set of preferences suitable for the given
-  // options |page|. Subclasses may change that set by calling AddPref() and
-  // RemovePref() afterwards.
-  ManagedPrefsBannerBase(PrefService* local_state,
-                         PrefService* user_prefs,
-                         OptionsPage page);
-
-  // Convenience constructor that fetches the local state PrefService from the
-  // global g_browser_process.
-  ManagedPrefsBannerBase(PrefService* user_prefs, OptionsPage page);
-
-  virtual ~ManagedPrefsBannerBase();
-
-  // Determine whether the banner should be visible.
-  bool DetermineVisibility() const;
-
-  // Add a local state preference as visibility trigger.
-  void AddLocalStatePref(const char* pref);
-  // Remove a local state preference from being a visibility trigger.
-  void RemoveLocalStatePref(const char* pref);
-
-  // Add a user preference as visibility trigger.
-  void AddUserPref(const char* pref);
-  // Remove a user preference from being a visibility trigger.
-  void RemoveUserPref(const char* pref);
-
- protected:
-  // Update banner visibility. This is called whenever a preference change is
-  // observed that may lead to changed visibility of the banner. Subclasses may
-  // override this in order to show/hide the banner.
-  virtual void OnUpdateVisibility() { }
-
- private:
-  // Initialization helper, called from the constructors.
-  void Init(PrefService* local_state,
-            PrefService* user_prefs,
-            OptionsPage page);
-
-  // |NotificationObserver| implementation.
-  virtual void Observe(int type,
-                       const NotificationSource& source,
-                       const NotificationDetails& details);
-
-  scoped_ptr<PrefSetObserver> local_state_set_;
-  scoped_ptr<PrefSetObserver> user_pref_set_;
-
-  DISALLOW_COPY_AND_ASSIGN(ManagedPrefsBannerBase);
-};
-
-}  // namespace policy
-
-#endif  // CHROME_BROWSER_POLICY_MANAGED_PREFS_BANNER_BASE_H_