Migrate upgrade notifications to observer

chrome/browser/ui/webui/settings/about_handler.h

 // Copyright 2016 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_SETTINGS_ABOUT_HANDLER_H_
 #define CHROME_BROWSER_UI_WEBUI_SETTINGS_ABOUT_HANDLER_H_
 
 #include <memory>
 #include <string>
 
 #include "base/compiler_specific.h"
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "base/strings/string16.h"
 #include "build/build_config.h"
 #include "chrome/browser/ui/webui/help/version_updater.h"
 #include "chrome/browser/ui/webui/settings/settings_page_ui_handler.h"
+#include "chrome/browser/upgrade_observer.h"
 #include "components/policy/core/common/policy_service.h"
-#include "content/public/browser/notification_observer.h"
-#include "content/public/browser/notification_registrar.h"
 #include "content/public/browser/web_ui_message_handler.h"
 
 #if defined(OS_CHROMEOS)
 #include "base/task/cancelable_task_tracker.h"
 #include "chromeos/system/version_loader.h"
 #endif  // defined(OS_CHROMEOS)
 
 namespace base {
 class DictionaryValue;
 class FilePath;
 class ListValue;
 }
 
 namespace content {
 class WebUIDataSource;
 }
 
 class Profile;
 
 namespace settings {
 
 // WebUI message handler for the help page.
 class AboutHandler : public settings::SettingsPageUIHandler,
-                     public content::NotificationObserver {
+                     public UpgradeObserver {
  public:
   AboutHandler();
   ~AboutHandler() override;
 
   static AboutHandler* Create(content::WebUIDataSource* html_source,
                               Profile* profile);
 
   // WebUIMessageHandler implementation.
   void RegisterMessages() override;
   void OnJavascriptAllowed() override;
   void OnJavascriptDisallowed() override;
 
-  // NotificationObserver implementation.
-  void Observe(int type,
-               const content::NotificationSource& source,
-               const content::NotificationDetails& details) override;
+  // UpgradeObserver implementation.
+  void OnUpgradeRecommended() override;
 
   // Returns the browser version as a string.
   static base::string16 BuildBrowserVersionString();
 
  private:
   void OnDeviceAutoUpdatePolicyChanged(const base::Value* previous_policy,
                                        const base::Value* current_policy);
 
   // Called once the JS page is ready to be called, serves as a signal to the
   // handler to register C++ observers.
@@ skipping 73 matching lines @@
 
   // Callback for when the regulatory text has been read.
   void OnRegulatoryLabelTextRead(std::string callback_id,
                                  const base::FilePath& label_dir_path,
                                  const std::string& text);
 #endif
 
   // Specialized instance of the VersionUpdater used to update the browser.
   std::unique_ptr<VersionUpdater> version_updater_;
 
-  // Used to observe notifications.
-  content::NotificationRegistrar registrar_;
-
   // Used to observe changes in the |kDeviceAutoUpdateDisabled| policy.
   std::unique_ptr<policy::PolicyChangeRegistrar> policy_registrar_;
 
+  // If true changes to UpgradeObserver are applied, if false they are ignored.
+  bool apply_changes_from_upgrade_observer_;
+
   // Used for callbacks.
   base::WeakPtrFactory<AboutHandler> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(AboutHandler);
 };
 
 }  // namespace settings
 
 #endif  // CHROME_BROWSER_UI_WEBUI_SETTINGS_ABOUT_HANDLER_H_