Enable user change background image in settings page in Aura build.

chrome/chrome_browser.gypi

 # 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.
 
 {
   'targets': [
     {
       'target_name': 'browser',
       'type': 'static_library',
       'variables': { 'enable_wexit_time_destructors': 1, },
@@ skipping 391 matching lines @@
         'browser/chrome_to_mobile_service.h',
         'browser/chrome_to_mobile_service_factory.cc',
         'browser/chrome_to_mobile_service_factory.h',
         'browser/chromeos/accessibility/accessibility_util.cc',
         'browser/chromeos/accessibility/accessibility_util.h',
         'browser/chromeos/audio/audio_handler.cc',
         'browser/chromeos/audio/audio_handler.h',
         'browser/chromeos/audio/audio_mixer.h',
         'browser/chromeos/audio/audio_mixer_alsa.cc',
         'browser/chromeos/audio/audio_mixer_alsa.h',
+        'browser/chromeos/background/desktop_background_observer.cc',
+        'browser/chromeos/background/desktop_background_observer.h',
         'browser/chromeos/bluetooth/bluetooth_adapter.cc',
         'browser/chromeos/bluetooth/bluetooth_adapter.h',
         'browser/chromeos/bluetooth/bluetooth_device.cc',
         'browser/chromeos/bluetooth/bluetooth_device.h',
         'browser/chromeos/boot_times_loader.cc',
         'browser/chromeos/boot_times_loader.h',
         'browser/chromeos/choose_mobile_network_dialog.cc',
         'browser/chromeos/choose_mobile_network_dialog.h',
         'browser/chromeos/chrome_browser_main_chromeos.cc',
         'browser/chromeos/chrome_browser_main_chromeos.h',
@@ skipping 3427 matching lines @@
         'browser/ui/webui/options2/chromeos/language_mozc_handler2.cc',
         'browser/ui/webui/options2/chromeos/language_mozc_handler2.h',
         'browser/ui/webui/options2/chromeos/language_options_util2.cc',
         'browser/ui/webui/options2/chromeos/language_options_util2.h',
         'browser/ui/webui/options2/chromeos/language_pinyin_handler2.cc',
         'browser/ui/webui/options2/chromeos/language_pinyin_handler2.h',
         'browser/ui/webui/options2/chromeos/pointer_handler2.cc',
         'browser/ui/webui/options2/chromeos/pointer_handler2.h',
         'browser/ui/webui/options2/chromeos/proxy_handler2.cc',
         'browser/ui/webui/options2/chromeos/proxy_handler2.h',
+        'browser/ui/webui/options2/chromeos/set_wallpaper_options_handler2.cc',
+        'browser/ui/webui/options2/chromeos/set_wallpaper_options_handler2.h',
         'browser/ui/webui/options2/chromeos/stats_options_handler2.cc',
         'browser/ui/webui/options2/chromeos/stats_options_handler2.h',
         'browser/ui/webui/options2/chromeos/system_settings_provider2.cc',
         'browser/ui/webui/options2/chromeos/system_settings_provider2.h',
         'browser/ui/webui/options2/chromeos/user_image_source2.cc',
         'browser/ui/webui/options2/chromeos/user_image_source2.h',
         'browser/ui/webui/options2/chromeos/virtual_keyboard_manager_handler2.cc',
         'browser/ui/webui/options2/chromeos/virtual_keyboard_manager_handler2.h',
         'browser/ui/webui/options2/clear_browser_data_handler2.cc',
         'browser/ui/webui/options2/clear_browser_data_handler2.h',
@@ skipping 1481 matching lines @@
          'variables': {
           'proto_in_dir': '../third_party/cros_system_api/dbus/',
           'proto_out_dir': 'chrome/browser/chromeos/dbus',
          },
          'includes': ['../build/protoc.gypi'],
         }],
       ],
     },
   ],
 }