[Gallery app] Make the background page use BackgroundBase class

ui/file_manager/gallery/js/compiled_resources.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.
 {
   'targets': [
     {
       'target_name': 'background',
       'variables': {
         'depends': [
           '../../../../third_party/jstemplate/compiled_resources.gyp:jstemplate',
           '../../../webui/resources/js/cr.js',
           '../../../webui/resources/js/cr/event_target.js',
           '../../../webui/resources/js/cr/ui.js',
           '../../../webui/resources/js/cr/ui/array_data_model.js',
           '../../../webui/resources/js/cr/ui/dialogs.js',
           '../../../webui/resources/js/load_time_data.js',
           '../../../webui/resources/js/util.js',
           '../../file_manager/common/js/util.js',
           '../../file_manager/common/js/async_util.js',
           '../../file_manager/common/js/volume_manager_common.js',
           '../../file_manager/common/js/error_util.js',
           '../../file_manager/common/js/file_type.js',
+          '../../file_manager/background/js/app_window_wrapper.js',
+          '../../file_manager/background/js/background_base.js',
           '../../file_manager/background/js/volume_manager.js',
         ],
         'externs': [
           '<(CLOSURE_DIR)/externs/chrome_send_externs.js',
           '<(CLOSURE_DIR)/externs/chrome_extensions.js',
           '<(CLOSURE_DIR)/externs/file_manager_private.js',
           '../../externs/chrome_test.js',
           '../../externs/gallery_background.js',
           '../../externs/platform.js',
         ],
@@ skipping 15 matching lines @@
           '../../../webui/resources/js/cr/event_target.js',
           '../../../webui/resources/js/cr/ui/touch_handler.js',
           '../../../webui/resources/js/cr/ui/array_data_model.js',
           '../../../webui/resources/js/cr/ui/dialogs.js',
           '../../../webui/resources/js/cr/ui/list_item.js',
           '../../../webui/resources/js/cr/ui/list_selection_model.js',
           '../../../webui/resources/js/cr/ui/list_single_selection_model.js',
           '../../../webui/resources/js/cr/ui/list_selection_controller.js',
           '../../../webui/resources/js/cr/ui/list.js',
           '../../../webui/resources/js/cr/ui/grid.js',
+          '../../../webui/resources/js/i18n_template_no_process.js',
           '../../file_manager/common/js/volume_manager_common.js',
           '../../file_manager/common/js/lru_cache.js',
           '../../file_manager/common/js/async_util.js',
           '../../file_manager/common/js/file_type.js',
           '../../file_manager/common/js/util.js',
           '../../file_manager/foreground/js/metrics_base.js',
           '../../file_manager/foreground/js/metrics.js',
           '../../file_manager/foreground/js/metadata/metadata_cache.js',
           '../../file_manager/foreground/js/metadata/exif_constants.js',
           '../../file_manager/foreground/js/mouse_inactivity_watcher.js',
@@ skipping 35 matching lines @@
           '../../externs/platform.js',
           '../../externs/webview_tag.js',
         ],
       },
       'includes': [
         '../../../../third_party/closure_compiler/compile_js.gypi'
       ],
     }
   ],
 }