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

chrome/browser/repost_form_warning_controller.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_REPOST_FORM_WARNING_CONTROLLER_H_
 #define CHROME_BROWSER_REPOST_FORM_WARNING_CONTROLLER_H_
 #pragma once
 
 #include "chrome/browser/tab_contents/constrained_window.h"
 #include "chrome/common/notification_observer.h"
@@ skipping 14 matching lines @@
 
   // Cancel the reload.
   void Cancel();
 
   // Continue the reload.
   void Continue();
 
  private:
   // NotificationObserver implementation.
   // Watch for a new load or a closed tab and dismiss the dialog if they occur.
-  void Observe(NotificationType type,
-               const NotificationSource& source,
-               const NotificationDetails& details);
+  virtual void Observe(NotificationType type,
+                       const NotificationSource& source,
+                       const NotificationDetails& details);
 
   // Close the warning dialog.
   void CloseDialog();
 
   NotificationRegistrar registrar_;
 
   // Tab contents, used to continue the reload.
   TabContents* tab_contents_;
 
   ConstrainedWindow* window_;
 
   DISALLOW_COPY_AND_ASSIGN(RepostFormWarningController);
 };
 
 #endif  // CHROME_BROWSER_REPOST_FORM_WARNING_CONTROLLER_H_