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

chrome/browser/ui/BUILD.gn

 # 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.
 
 import("//build/config/chromecast_build.gni")
 import("//build/config/crypto.gni")
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
 import("//build/split_static_library.gni")
 import("//chrome/common/features.gni")
@@ skipping 1474 matching lines @@
       "views/cookie_info_view.cc",
       "views/cookie_info_view.h",
       "views/device_chooser_content_view.cc",
       "views/device_chooser_content_view.h",
       "views/download/download_danger_prompt_views.cc",
       "views/elevation_icon_setter.cc",
       "views/elevation_icon_setter.h",
       "views/exclusive_access_bubble_views.cc",
       "views/exclusive_access_bubble_views.h",
       "views/exclusive_access_bubble_views_context.h",
+      "views/extensions/bookmark_app_confirmation_view.cc",
+      "views/extensions/bookmark_app_confirmation_view.h",
       "views/extensions/chooser_dialog_view.cc",
       "views/extensions/chooser_dialog_view.h",
       "views/extensions/extension_install_dialog_view.cc",
       "views/extensions/extension_install_dialog_view.h",
       "views/extensions/extension_keybinding_registry_views.cc",
       "views/extensions/extension_keybinding_registry_views.h",
       "views/frame/native_widget_mac_frameless_nswindow.h",
       "views/frame/native_widget_mac_frameless_nswindow.mm",
       "views/global_error_bubble_view.cc",
       "views/global_error_bubble_view.h",
@@ skipping 137 matching lines @@
     # TODO(tonikitoo): It seems sensible to make it possible to opt-in
     # the use of these files in case Gtk is available with its Wayland.
     if (use_aura && !use_ozone && is_desktop_linux) {
       sources += [
         "views/chrome_browser_main_extra_parts_views_linux.cc",
         "views/chrome_browser_main_extra_parts_views_linux.h",
       ]
     }
     if (enable_extensions && (!is_mac || mac_views_browser)) {
       sources += [
-        "views/extensions/bookmark_app_confirmation_view.cc",
-        "views/extensions/bookmark_app_confirmation_view.h",
         "views/extensions/browser_action_drag_data.cc",
         "views/extensions/browser_action_drag_data.h",
         "views/extensions/extension_action_platform_delegate_views.cc",
         "views/extensions/extension_action_platform_delegate_views.h",
         "views/extensions/extension_dialog.cc",
         "views/extensions/extension_dialog.h",
         "views/extensions/extension_dialog_observer.cc",
         "views/extensions/extension_dialog_observer.h",
         "views/extensions/extension_installed_bubble_view.cc",
         "views/extensions/extension_popup.cc",
@@ skipping 1939 matching lines @@
     deps += [
       "//chrome/test:test_support_ui",
       "//components/zoom",
     ]
   }
 
   if (enable_extensions) {
     deps += [ "//extensions/browser" ]
   }
 }