Asynchronously load wallpapers when user pod is selected.

chrome/browser/chromeos/background/ash_user_wallpaper_delegate.cc

Index: chrome/browser/chromeos/background/ash_user_wallpaper_delegate.cc
diff --git a/chrome/browser/chromeos/background/desktop_background_observer.cc b/chrome/browser/chromeos/background/ash_user_wallpaper_delegate.cc
similarity index 68%
rename from chrome/browser/chromeos/background/desktop_background_observer.cc
rename to chrome/browser/chromeos/background/ash_user_wallpaper_delegate.cc
index 3cc21fac8c577678e51da0f4137d1cfd4872052f..ece4f3c50a41f336f838fbecd58ef81ff843b065 100644
--- a/chrome/browser/chromeos/background/desktop_background_observer.cc
+++ b/chrome/browser/chromeos/background/ash_user_wallpaper_delegate.cc
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "chrome/browser/chromeos/background/desktop_background_observer.h"
+#include "chrome/browser/chromeos/background/ash_user_wallpaper_delegate.h"
 
 #include "ash/shell.h"
 #include "ash/desktop_background/desktop_background_controller.h"
@@ -51,28 +51,4 @@ ash::UserWallpaperDelegate* CreateUserWallpaperDelegate() {
   return new chromeos::UserWallpaperDelegate();
 }
 
-DesktopBackgroundObserver::DesktopBackgroundObserver() {
-  registrar_.Add(
-      this,
-      chrome::NOTIFICATION_LOGIN_USER_CHANGED,
-      content::NotificationService::AllSources());
-}
-
-DesktopBackgroundObserver::~DesktopBackgroundObserver() {
-}
-
-void DesktopBackgroundObserver::Observe(int type,
-    const content::NotificationSource& source,
-    const content::NotificationDetails& details) {
-  switch (type) {
-    case chrome::NOTIFICATION_LOGIN_USER_CHANGED: {
-      ash::Shell::GetInstance()->desktop_background_controller()->
-          SetDesktopBackgroundImageMode();
-      break;
-    }
-    default:
-      NOTREACHED();
-  }
-}
-
 }  // namespace chromeos