Reload wallpaper when display configuration changes.

ash/shell/shell_delegate_impl.cc

 // 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.
 
 #include "ash/shell/shell_delegate_impl.h"
 
 #include <limits>
 
 #include "ash/caps_lock_delegate_stub.h"
+#include "ash/default_user_wallpaper_delegate.h"
 #include "ash/host/root_window_host_factory.h"
 #include "ash/keyboard_controller_proxy_stub.h"
 #include "ash/session_state_delegate.h"
 #include "ash/session_state_delegate_stub.h"
 #include "ash/shell/context_menu.h"
 #include "ash/shell/example_factory.h"
 #include "ash/shell/launcher_delegate_impl.h"
 #include "ash/shell/toplevel_window.h"
 #include "ash/shell_window_ids.h"
 #include "ash/system/tray/default_system_tray_delegate.h"
@@ skipping 146 matching lines @@
     ash::LauncherModel* model) {
   launcher_delegate_ = new LauncherDelegateImpl(watcher_);
   return launcher_delegate_;
 }
 
 ash::SystemTrayDelegate* ShellDelegateImpl::CreateSystemTrayDelegate() {
   return new DefaultSystemTrayDelegate;
 }
 
 ash::UserWallpaperDelegate* ShellDelegateImpl::CreateUserWallpaperDelegate() {
-  return NULL;
+  return new DefaultUserWallpaperDelegate();
 }
 
 ash::CapsLockDelegate* ShellDelegateImpl::CreateCapsLockDelegate() {
   return new CapsLockDelegateStub;
 }
 
 ash::SessionStateDelegate* ShellDelegateImpl::CreateSessionStateDelegate() {
   return new SessionStateDelegateStub;
 }
 
@@ skipping 30 matching lines @@
 RootWindowHostFactory* ShellDelegateImpl::CreateRootWindowHostFactory() {
   return RootWindowHostFactory::Create();
 }
 
 base::string16 ShellDelegateImpl::GetProductName() const {
   return base::string16();
 }
 
 }  // namespace shell
 }  // namespace ash