Revert of Remove Enable Exits On Suspend flags on iOS

ios/chrome/ios_chrome.gyp

 # 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.
 
 {
   'variables': {
     'chromium_code': 1,
   },
   'targets': [
     {
       # GN version: //ios/chrome/app
       'target_name': 'ios_chrome_app',
       'type': 'static_library',
       'include_dirs': [
         '../..',
       ],
       'dependencies': [
         '../../base/base.gyp:base',
         'ios_chrome_browser',
       ],
       'link_settings': {
         'libraries': [
           '$(SDKROOT)/System/Library/Frameworks/Foundation.framework',
           '$(SDKROOT)/System/Library/Frameworks/UIKit.framework',
         ],
       },
       'sources': [
+        'app/UIApplication+ExitsOnSuspend.h',
+        'app/UIApplication+ExitsOnSuspend.mm',
         'app/application_delegate/memory_warning_helper.h',
         'app/application_delegate/memory_warning_helper.mm',
         'app/deferred_initialization_runner.h',
         'app/deferred_initialization_runner.mm',
         'app/safe_mode_crashing_modules_config.h',
         'app/safe_mode_crashing_modules_config.mm',
         'app/safe_mode_util.cc',
         'app/safe_mode_util.h',
       ],
     },
@@ skipping 845 matching lines @@
             '../../components/components.gyp:omnibox_browser',
             '../../components/components.gyp:rlz',
             '../../components/components.gyp:search_engines',
             '../../rlz/rlz.gyp:rlz_lib',
           ],
         },
       ],
     }],
   ],
 }