Add the "virtual" keyword on method overrides that are missing it.

chrome/browser/gtk/options/passwords_page_gtk.h

 // Copyright (c) 2010 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_GTK_OPTIONS_PASSWORDS_PAGE_GTK_H_
 #define CHROME_BROWSER_GTK_OPTIONS_PASSWORDS_PAGE_GTK_H_
 #pragma once
 
 #include <gtk/gtk.h>
 
@@ skipping 20 matching lines @@
   PasswordStore* GetPasswordStore();
 
   // Sets the password list contents to the given data. We take ownership of
   // the PasswordForms in the vector.
   void SetPasswordList(const std::vector<webkit_glue::PasswordForm*>& result);
 
   // Helper that hides the password.
   void HidePassword();
 
   // NotificationObserver implementation.
-  void Observe(NotificationType type,
-               const NotificationSource& source,
-               const NotificationDetails& details);
+  virtual void Observe(NotificationType type,
+                       const NotificationSource& source,
+                       const NotificationDetails& details);
 
   // Handles changes to the observed preferences and updates the UI.
   void OnPrefChanged(const std::string& pref_name);
 
   CHROMEGTK_CALLBACK_0(PasswordsPageGtk, void, OnRemoveButtonClicked);
   CHROMEGTK_CALLBACK_0(PasswordsPageGtk, void, OnRemoveAllButtonClicked);
   CHROMEGTK_CALLBACK_1(PasswordsPageGtk, void, OnRemoveAllConfirmResponse, int);
   CHROMEGTK_CALLBACK_0(PasswordsPageGtk, void, OnShowPasswordButtonClicked);
   CHROMEGTK_CALLBACK_0(PasswordsPageGtk, void, OnShowPasswordButtonRealized);
 
@@ skipping 50 matching lines @@
   GtkWidget* page_;
 
   Profile* profile_;
   BooleanPrefMember allow_show_passwords_;
   std::vector<webkit_glue::PasswordForm*> password_list_;
 
   DISALLOW_COPY_AND_ASSIGN(PasswordsPageGtk);
 };
 
 #endif  // CHROME_BROWSER_GTK_OPTIONS_PASSWORDS_PAGE_GTK_H_