Separate the logic of popup alignment and workarea handling as delegate.

ui/message_center/message_center.gyp

 # Copyright (c) 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': {
     'chromium_code': 1,
   },
   'targets': [
     {
@@ skipping 54 matching lines @@
         'notification_blocker.h',
         'notification_list.cc',
         'notification_list.h',
         'notification_types.cc',
         'notification_types.h',
         'notifier_settings.cc',
         'notifier_settings.h',
         'views/bounded_label.cc',
         'views/bounded_label.h',
         'views/constants.h',
+        'views/desktop_popup_alignment_delegate.cc',
+        'views/desktop_popup_alignment_delegate.h',
         'views/message_bubble_base.cc',
         'views/message_bubble_base.h',
         'views/message_center_controller.h',
         'views/message_center_bubble.cc',
         'views/message_center_bubble.h',
         'views/message_center_button_bar.cc',
         'views/message_center_button_bar.h',
         'views/message_center_view.cc',
         'views/message_center_view.h',
         'views/message_popup_collection.cc',
         'views/message_popup_collection.h',
         'views/message_view.cc',
         'views/message_view.h',
         'views/message_view_context_menu_controller.cc',
         'views/message_view_context_menu_controller.h',
         'views/notifier_settings_view.cc',
         'views/notifier_settings_view.h',
         'views/notification_button.cc',
         'views/notification_button.h',
         'views/notification_view.cc',
         'views/notification_view.h',
         'views/padded_button.cc',
         'views/padded_button.h',
+        'views/popup_alignment_delegate.cc',
+        'views/popup_alignment_delegate.h',
         'views/proportional_image_view.cc',
         'views/proportional_image_view.h',
         'views/toast_contents_view.cc',
         'views/toast_contents_view.h',
       ],
       # TODO(jschuh): crbug.com/167187 fix size_t to int truncations.
       'msvs_disabled_warnings': [ 4267, ],
       'conditions': [
         # This condition is for Windows 8 Metro mode support.  We need to
         # specify a particular desktop during widget creation in that case.
@@ skipping 130 matching lines @@
         # See http://crbug.com/162998#c4 for why this is needed.
         ['OS=="linux" and use_allocator!="none"', {
           'dependencies': [
             '../../base/allocator/allocator.gyp:allocator',
           ],
         }],
       ],
     },  # target_name: message_center_unittests
   ],
 }