app_list: Add transition for apps grid and search results.

ui/app_list/app_list.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 19 matching lines @@
         'app_list_item_model_observer.h',
         'app_list_item_view.cc',
         'app_list_item_view.h',
         'app_list_model.cc',
         'app_list_model.h',
         'app_list_view.cc',
         'app_list_view.h',
         'app_list_view_delegate.h',
         'apps_grid_view.cc',
         'apps_grid_view.h',
+        'contents_view.cc',
+        'contents_view.h',
         'drop_shadow_label.cc',
         'drop_shadow_label.h',
         'icon_cache.cc',
         'icon_cache.h',
         'page_switcher.cc',
         'page_switcher.h',
         'pagination_model.cc',
         'pagination_model.h',
         'pagination_model_observer.h',
         'search_box_model.h',
@@ skipping 26 matching lines @@
       ],
       'sources': [
         'apps_grid_view_unittest.cc',
         'test/app_list_test_suite.cc',
         'test/app_list_test_suite.h',
         'test/run_all_unittests.cc',
       ],
     },
   ],
 }