Convert ValidationMessageBubbleView to BubbleDialogDelegate

chrome/browser/ui/cocoa/tab_dialogs_cocoa.mm

 // Copyright 2014 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.
 
 #include "chrome/browser/ui/cocoa/tab_dialogs_cocoa.h"
 
 #include "base/memory/ptr_util.h"
 #import "chrome/browser/ui/cocoa/content_settings/collected_cookies_mac.h"
 #import "chrome/browser/ui/cocoa/hung_renderer_controller.h"
 #import "chrome/browser/ui/cocoa/passwords/passwords_bubble_cocoa.h"
@@ skipping 50 matching lines @@
 }
 
 void TabDialogsCocoa::ShowManagePasswordsBubble(bool user_action) {
   ManagePasswordsBubbleCocoa::Show(web_contents_, user_action);
 }
 
 void TabDialogsCocoa::HideManagePasswordsBubble() {
   // The bubble is closed when it loses the focus.
 }
 
-std::unique_ptr<ValidationMessageBubble> TabDialogsCocoa::ShowValidationMessage(
+base::WeakPtr<ValidationMessageBubble> TabDialogsCocoa::ShowValidationMessage(
     const gfx::Rect& anchor_in_root_view,
     const base::string16& main_text,
     const base::string16& sub_text) {
-  return base::WrapUnique(new ValidationMessageBubbleCocoa(
-      web_contents_, anchor_in_root_view, main_text, sub_text));
+  return (new ValidationMessageBubbleCocoa(
+      web_contents_, anchor_in_root_view, main_text, sub_text))->AsWeakPtr();
 }