WebUI: Add JavaScript lifecycle-control to WebUIMessageHandler.

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

Index: chrome/browser/ui/webui/settings/profile_info_handler.h
diff --git a/chrome/browser/ui/webui/settings/profile_info_handler.h b/chrome/browser/ui/webui/settings/profile_info_handler.h
index 015efcdec49f009d90206d0ab65f4140f4ece0bb..e0ab2adbc3688ee78d597cc9ffb892f4643e3104 100644
--- a/chrome/browser/ui/webui/settings/profile_info_handler.h
+++ b/chrome/browser/ui/webui/settings/profile_info_handler.h
@@ -34,7 +34,8 @@ class ProfileInfoHandler : public SettingsPageUIHandler,
 
   // SettingsPageUIHandler implementation.
   void RegisterMessages() override;
-  void RenderViewReused() override;
+  void OnJavascriptAllowed() override;
+  void OnJavascriptDisallowed() override;
 
 #if defined(OS_CHROMEOS)
   // content::NotificationObserver implementation.
@@ -67,8 +68,6 @@ class ProfileInfoHandler : public SettingsPageUIHandler,
   content::NotificationRegistrar registrar_;
 #endif
 
-  bool observers_registered_;
-
   DISALLOW_COPY_AND_ASSIGN(ProfileInfoHandler);
 };