ui: Have shell_dialogs into its own gyp file under its shell_dialogs/ directory.

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 146 matching lines @@
       ],
     },  # target_name: message_center_test_support
     {
       'target_name': 'message_center_unittests',
       'type': 'executable',
       'dependencies': [
         '../../base/base.gyp:base',
         '../../base/base.gyp:test_support_base',
         '../../skia/skia.gyp:skia',
         '../../testing/gtest.gyp:gtest',
+        '../../url/url.gyp:url_lib',
         '../events/events.gyp:events',
         '../gfx/gfx.gyp:gfx',
-        '../ui.gyp:run_ui_unittests',
         '../ui.gyp:ui',
-        '../../url/url.gyp:url_lib',
+        '../ui_unittests.gyp:run_ui_unittests',
         'message_center',
         'message_center_test_support',
       ],
       'sources': [
         'cocoa/notification_controller_unittest.mm',
         'cocoa/popup_collection_unittest.mm',
         'cocoa/popup_controller_unittest.mm',
         'cocoa/settings_controller_unittest.mm',
         'cocoa/status_item_view_unittest.mm',
         'cocoa/tray_controller_unittest.mm',
         'cocoa/tray_view_controller_unittest.mm',
         'message_center_tray_unittest.cc',
         'message_center_impl_unittest.cc',
         'notification_list_unittest.cc',
         'test/run_all_unittests.cc',
       ],
       'conditions': [
         ['OS=="mac"', {
           'dependencies': [
-            '../ui.gyp:ui_test_support',
+            '../ui_unittests.gyp:ui_test_support',
           ],
         }],
         ['toolkit_views==1', {
           'dependencies': [
             # Compositor is needed by message_center_view_unittest.cc
             # and for the fonts used by bounded_label_unittest.cc.
             '../compositor/compositor.gyp:compositor',
             '../views/views.gyp:views',
             '../views/views.gyp:views_test_support',
           ],
@@ skipping 13 matching lines @@
         # See http://crbug.com/162998#c4 for why this is needed.
         ['OS=="linux" and linux_use_tcmalloc==1', {
           'dependencies': [
             '../../base/allocator/allocator.gyp:allocator',
           ],
         }],
       ],
     },  # target_name: message_center_unittests
   ],
 }