In WinAura, also kill the Metro viewer process in AttemptExit().

chrome/chrome_browser.gypi

 # Copyright 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.
 
 {
   'targets': [
     {
       'target_name': 'browser',
       'type': 'static_library',
       'variables': { 'enable_wexit_time_destructors': 1, },
@@ skipping 260 matching lines @@
         'browser/bookmarks/bookmark_utils.h',
         'browser/bookmarks/imported_bookmark_entry.cc',
         'browser/bookmarks/imported_bookmark_entry.h',
         'browser/browser_about_handler.cc',
         'browser/browser_about_handler.h',
         'browser/browser_process.cc',
         'browser/browser_process.h',
         'browser/browser_process_impl.cc',
         'browser/browser_process_impl.h',
         'browser/browser_process_platform_part.h',
+        'browser/browser_process_platform_part_android.cc',
+        'browser/browser_process_platform_part_android.h',
         'browser/browser_process_platform_part_aurawin.cc',
         'browser/browser_process_platform_part_aurawin.h',
         'browser/browser_process_platform_part_base.cc',
         'browser/browser_process_platform_part_base.h',
         'browser/browser_process_platform_part_chromeos.cc',
         'browser/browser_process_platform_part_chromeos.h',
+        'browser/browser_process_platform_part_mac.h',
+        'browser/browser_process_platform_part_mac.mm',
         'browser/browser_shutdown.cc',
         'browser/browser_shutdown.h',
         'browser/browser_util_win.cc',
         'browser/browser_util_win.h',
         'browser/browsing_data/browsing_data_appcache_helper.cc',
         'browser/browsing_data/browsing_data_appcache_helper.h',
         'browser/browsing_data/browsing_data_database_helper.cc',
         'browser/browsing_data/browsing_data_database_helper.h',
         'browser/browsing_data/browsing_data_file_system_helper.cc',
         'browser/browsing_data/browsing_data_file_system_helper.h',
@@ skipping 2914 matching lines @@
             'package_name': 'org/chromium/chrome/browser/ui/toolbar',
             'template_deps': ['browser/ui/toolbar/toolbar_model_security_level_list.h'],
           },
           'includes': [ '../build/android/java_cpp_template.gypi' ],
         },
       ],
      },
     ],
   ],
 }