Move all wallpaper file loading and decoding from DesktopBackgroundController to WallpaperManager.

ash/ash.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,
     'grit_out_dir': '<(SHARED_INTERMEDIATE_DIR)/chrome',
   },
   'includes': [
@@ skipping 735 matching lines @@
       'dependencies': [
         '../skia/skia.gyp:skia',
         '../testing/gtest.gyp:gtest',
         '../ui/accessibility/accessibility.gyp:ax_gen',
         '../ui/app_list/app_list.gyp:app_list_test_support',
         '../ui/views/views.gyp:views_test_support',
         'ash',
         'ash_resources',
       ],
       'sources': [
+        'desktop_background/desktop_background_controller_test_api.cc',
+        'desktop_background/desktop_background_controller_test_api.h',
         'shell/keyboard_controller_proxy_stub.cc',
         'shell/keyboard_controller_proxy_stub.h',
         'shell/toplevel_window.cc',
         'shell/toplevel_window.h',
         'test/app_list_controller_test_api.cc',
         'test/app_list_controller_test_api.h',
         'test/ash_test_base.cc',
         'test/ash_test_base.h',
         'test/ash_test_helper.cc',
         'test/ash_test_helper.h',
@@ skipping 373 matching lines @@
         }],
         ['chromeos==1', {
           'dependencies': [
             '../device/bluetooth/bluetooth.gyp:device_bluetooth',
           ],
         }],
       ],
     },
   ],
 }