Fix wallpaper change to a random one when user first click "set wallpaper".

chrome/browser/chromeos/background/desktop_background_observer.cc

Index: chrome/browser/chromeos/background/desktop_background_observer.cc
diff --git a/chrome/browser/chromeos/background/desktop_background_observer.cc b/chrome/browser/chromeos/background/desktop_background_observer.cc
index bb0372182f110aecd3a6be62dcbd95955e9cc94c..49f7eff5190c9d32dd5473b8babd2e5e26b1ef51 100644
--- a/chrome/browser/chromeos/background/desktop_background_observer.cc
+++ b/chrome/browser/chromeos/background/desktop_background_observer.cc
@@ -28,17 +28,7 @@ class UserWallpaperDelegate: public ash::UserWallpaperDelegate {
   }
 
   virtual const int GetUserWallpaperIndex() OVERRIDE {
-    chromeos::UserManager* user_manager = chromeos::UserManager::Get();
-    // If at login screen or logged in as a guest/incognito user, then use the
-    // default wallpaper.
-    if (user_manager->IsLoggedInAsGuest() || !user_manager->IsUserLoggedIn())
-      return ash::GetGuestWallpaperIndex();
-
-    const chromeos::User& user = user_manager->GetLoggedInUser();
-    DCHECK(!user.email().empty());
-    int index = user_manager->GetUserWallpaper(user.email());
-    DCHECK(index >=0 && index < ash::GetWallpaperCount());
-    return index;
+    return chromeos::UserManager::Get()->GetUserWallpaperIndex();
   }
 
   virtual void OpenSetWallpaperPage() OVERRIDE {