Use BookmarkAppConfirmationView on Mac. Delete the NSAlert Mac uses currently.

chrome/browser/ui/cocoa/browser_window_cocoa.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_COCOA_BROWSER_WINDOW_COCOA_H_
 #define CHROME_BROWSER_UI_COCOA_BROWSER_WINDOW_COCOA_H_
 
 #include "base/mac/scoped_nsobject.h"
 #include "base/memory/weak_ptr.h"
 #include "chrome/browser/extensions/extension_keybinding_registry.h"
@@ skipping 87 matching lines @@
   void FocusBookmarksToolbar() override;
   void FocusInfobars() override;
   void RotatePaneFocus(bool forwards) override;
   bool IsBookmarkBarVisible() const override;
   bool IsBookmarkBarAnimating() const override;
   bool IsTabStripEditable() const override;
   bool IsToolbarVisible() const override;
   bool IsToolbarShowing() const override;
   void ShowUpdateChromeDialog() override;
   void ShowBookmarkBubble(const GURL& url, bool already_bookmarked) override;
-  void ShowBookmarkAppBubble(
-      const WebApplicationInfo& web_app_info,
-      const ShowBookmarkAppBubbleCallback& callback) override;
   autofill::SaveCardBubbleView* ShowSaveCreditCardBubble(
       content::WebContents* contents,
       autofill::SaveCardBubbleController* controller,
       bool user_gesture) override;
   ShowTranslateBubbleResult ShowTranslateBubble(
       content::WebContents* contents,
       translate::TranslateStep step,
       translate::TranslateErrors::Type error_type,
       bool is_user_gesture) override;
 #if BUILDFLAG(ENABLE_ONE_CLICK_SIGNIN)
@@ skipping 73 matching lines @@
   ui::WindowShowState initial_show_state_;
   NSInteger attention_request_id_;  // identifier from requestUserAttention
 
   // Preserves window alert state to show appropriate icon in the window title
   // which can be audio playing, muting or none (determined by alert state of
   // tabs.
   TabAlertState alert_state_;
 };
 
 #endif  // CHROME_BROWSER_UI_COCOA_BROWSER_WINDOW_COCOA_H_