Define PushMessagingApplicationId and replace ad-hoc code.

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.
 
 {
   'variables': {
     # All .cc, .h, .m, and .mm files under browser except for:
     # * tests and mocks.
     # * code below browser/chromeos
     # * code below browser/extensions
@@ skipping 1156 matching lines @@
       'browser/search_engines/ui_thread_search_terms_data.cc',
       'browser/search_engines/ui_thread_search_terms_data.h',
       'browser/search_engines/ui_thread_search_terms_data_android.cc',
       'browser/search_engines/ui_thread_search_terms_data_android.h',
       'browser/services/gcm/gcm_account_tracker.cc',
       'browser/services/gcm/gcm_account_tracker.h',
       'browser/services/gcm/gcm_profile_service.cc',
       'browser/services/gcm/gcm_profile_service.h',
       'browser/services/gcm/gcm_profile_service_factory.cc',
       'browser/services/gcm/gcm_profile_service_factory.h',
+      'browser/services/gcm/push_messaging_application_id.cc',
+      'browser/services/gcm/push_messaging_application_id.h',
       'browser/services/gcm/push_messaging_infobar_delegate.cc',
       'browser/services/gcm/push_messaging_infobar_delegate.h',
       'browser/services/gcm/push_messaging_permission_context.cc',
       'browser/services/gcm/push_messaging_permission_context.h',
       'browser/services/gcm/push_messaging_permission_context_factory.cc',
       'browser/services/gcm/push_messaging_permission_context_factory.h',
       'browser/services/gcm/push_messaging_service_impl.cc',
       'browser/services/gcm/push_messaging_service_impl.h',
       'browser/sessions/base_session_service.cc',
       'browser/sessions/base_session_service.h',
@@ skipping 2406 matching lines @@
             'package_name': 'org/chromium/chrome/browser',
             'template_deps': ['browser/android/tab_load_status.h'],
           },
           'includes': [ '../build/android/java_cpp_template.gypi' ],
         },
       ],
      },
     ],
   ],
 }