Fix crash when user closes window prior to the "Confirm Install" prompt showing

chrome/chrome_browser_extensions.gypi

 # Copyright (c) 2013 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.
 
 {
   'variables': {
     'chrome_browser_extensions_chromeos_sources': [
       'browser/extensions/api/diagnostics/diagnostics_api.cc',
       'browser/extensions/api/diagnostics/diagnostics_api.h',
       'browser/extensions/api/diagnostics/diagnostics_api_chromeos.cc',
@@ skipping 589 matching lines @@
       'browser/extensions/extension_icon_manager.cc',
       'browser/extensions/extension_icon_manager.h',
       'browser/extensions/extension_infobar_delegate.cc',
       'browser/extensions/extension_infobar_delegate.h',
       'browser/extensions/extension_install_checker.cc',
       'browser/extensions/extension_install_checker.h',
       'browser/extensions/extension_install_prompt.cc',
       'browser/extensions/extension_install_prompt.h',
       'browser/extensions/extension_install_prompt_experiment.cc',
       'browser/extensions/extension_install_prompt_experiment.h',
+      'browser/extensions/extension_install_prompt_show_params.cc',
+      'browser/extensions/extension_install_prompt_show_params.h',
       'browser/extensions/extension_install_ui_util.cc',
       'browser/extensions/extension_install_ui_util.h',
       'browser/extensions/extension_keybinding_registry.cc',
       'browser/extensions/extension_keybinding_registry.h',
       'browser/extensions/extension_management.cc',
       'browser/extensions/extension_management.h',
       'browser/extensions/extension_management_constants.cc',
       'browser/extensions/extension_management_constants.h',
       'browser/extensions/extension_management_internal.cc',
       'browser/extensions/extension_management_internal.h',
@@ skipping 485 matching lines @@
           ],
         }, {  # use_brlapi==0
           'sources': [
             'browser/extensions/api/braille_display_private/braille_controller_stub.cc',
           ],
         }],
       ],
     },
   ],
 }