WebUI: Add JavaScript lifecycle-control to WebUIMessageHandler.

chrome/browser/ui/webui/settings/profile_info_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_PROFILE_INFO_HANDLER_H_
 #define CHROME_BROWSER_UI_WEBUI_SETTINGS_PROFILE_INFO_HANDLER_H_
 
 #include <memory>
 
 #include "base/macros.h"
@@ skipping 16 matching lines @@
 #endif
                            public ProfileAttributesStorage::Observer {
  public:
   static const char kProfileInfoChangedEventName[];
 
   explicit ProfileInfoHandler(Profile* profile);
   ~ProfileInfoHandler() override {}
 
   // SettingsPageUIHandler implementation.
   void RegisterMessages() override;
-  void RenderViewReused() override;
+  void OnJavascriptAllowed() override;
+  void OnJavascriptDisallowed() override;
 
 #if defined(OS_CHROMEOS)
   // content::NotificationObserver implementation.
   void Observe(int type,
                const content::NotificationSource& source,
                const content::NotificationDetails& details) override;
 #endif
 
   // ProfileAttributesStorage::Observer implementation.
   void OnProfileNameChanged(const base::FilePath& profile_path,
@@ skipping 12 matching lines @@
   std::unique_ptr<base::DictionaryValue> GetAccountNameAndIcon() const;
 
   // Weak pointer.
   Profile* profile_;
 
 #if defined(OS_CHROMEOS)
   // Used to listen to ChromeOS user image changes.
   content::NotificationRegistrar registrar_;
 #endif
 
-  bool observers_registered_;
-
   DISALLOW_COPY_AND_ASSIGN(ProfileInfoHandler);
 };
 
 }  // namespace settings
 
 #endif  // CHROME_BROWSER_UI_WEBUI_SETTINGS_PROFILE_INFO_HANDLER_H_