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

ash/desktop_background/desktop_background_controller.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/desktop_background/desktop_background_controller.h"
+
+#include "ash/desktop_background/desktop_background_resources.h"
+#include "ash/shell.h"
+#include "base/logging.h"
+#include "chrome/browser/chromeos/login/user_manager.h"
+#include "chrome/common/chrome_notification_types.h"
+#include "content/public/browser/notification_service.h"
+#include "ui/gfx/image/image.h"
+#include "grit/ui_resources.h"

[flackr, 2012/03/06 17:16:49]

nit: Sort

[bshe, 2012/03/06 19:56:16]

Done.

+#include "ui/base/resource/resource_bundle.h"
+
+namespace ash {
+
+DesktopBackgroundController::DesktopBackgroundController(){
+  registrar_.Add(
+      this,
+      chrome::NOTIFICATION_DESKTOP_BACKGROUND_CHANGED,
+      content::NotificationService::AllSources());
+  registrar_.Add(
+      this,
+      chrome::NOTIFICATION_LOGIN_USER_CHANGED,
+      content::NotificationService::AllSources());
+}
+
+DesktopBackgroundController::~DesktopBackgroundController() {
+}
+
+void DesktopBackgroundController::OnDesktopBackgroundChange(int index) {
+  DCHECK(index >=0 && index < kDefaultWallpaperCount);
+  Shell::GetInstance()->SetDesktopBackgroundWallpaper(
+      GetDefaultWallpaper(index));
+}
+
+void  DesktopBackgroundController::Observe(int type,
+    const content::NotificationSource& source,
+    const content::NotificationDetails& details) {
+  switch (type) {
+    case chrome::NOTIFICATION_DESKTOP_BACKGROUND_CHANGED: {
+      int index = *content::Details<int>(details).ptr();
+      Shell::GetInstance()->desktop_background_controller()
+          ->OnDesktopBackgroundChange(index);
+      break;
+    }
+    case chrome::NOTIFICATION_LOGIN_USER_CHANGED: {
+      chromeos::UserManager* user_manager = chromeos::UserManager::Get();
+      const chromeos::User& user = user_manager->logged_in_user();
+      int index = user_manager->GetUserWallpaper(user.email());
+      Shell::GetInstance()->desktop_background_controller()

[flackr, 2012/03/06 17:16:49]

Shell::GetInstance()->desktop_background_controller() should be the same as
"this". Just directly call OnDesktopBackgroundChange(index);

[bshe, 2012/03/06 19:56:16]

Done. The desktop_background_controller function in Shell will probably be used
in the future for customized wallpaper. Should I keep it in shell for future use
or just remove it for sanity?

+          ->OnDesktopBackgroundChange(index);
+      break;
+    }
+    default:
+      NOTREACHED();
+  }
+}
+
+}  // namespace ash