Convert ValidationMessageBubbleView to BubbleDialogDelegate

chrome/browser/ui/browser.h

 // Copyright (c) 2012 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_BROWSER_H_
 #define CHROME_BROWSER_UI_BROWSER_H_
 
 #include <stdint.h>
 
 #include <map>
@@ skipping 984 matching lines @@
 
   std::unique_ptr<ExclusiveAccessManager> exclusive_access_manager_;
 
   std::unique_ptr<extensions::WindowController> extension_window_controller_;
 
   std::unique_ptr<chrome::BrowserCommandController> command_controller_;
 
   // True if the browser window has been shown at least once.
   bool window_has_shown_;
 
-  std::unique_ptr<ValidationMessageBubble> validation_message_bubble_;
+  base::WeakPtr<ValidationMessageBubble> validation_message_bubble_;
 
   SigninViewController signin_view_controller_;
 
   std::unique_ptr<ScopedKeepAlive> keep_alive_;
 
   // The following factory is used for chrome update coalescing.
   base::WeakPtrFactory<Browser> chrome_updater_factory_;
 
   // The following factory is used to close the frame at a later time.
   base::WeakPtrFactory<Browser> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(Browser);
 };
 
 #endif  // CHROME_BROWSER_UI_BROWSER_H_