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

chrome/browser/chromeos/login/user_manager_impl.h

Index: chrome/browser/chromeos/login/user_manager_impl.h
diff --git a/chrome/browser/chromeos/login/user_manager_impl.h b/chrome/browser/chromeos/login/user_manager_impl.h
index 1abfdcc7c55a6f9f443a012aba108ed8d83db561..df8ed09a9786e3ef0da40bee65b3271f1e3836dd 100644
--- a/chrome/browser/chromeos/login/user_manager_impl.h
+++ b/chrome/browser/chromeos/login/user_manager_impl.h
@@ -60,6 +60,9 @@ class UserManagerImpl : public UserManager,
                                     const std::string& display_email) OVERRIDE;
   virtual std::string GetUserDisplayEmail(
       const std::string& username) const OVERRIDE;
+  virtual int GetUserWallpaper(const std::string& username) OVERRIDE;
+  virtual void SaveWallpaperDefaultIndex(const std::string& username,
+                                         int wallpaper_index) OVERRIDE;
   virtual void SaveUserDefaultImageIndex(const std::string& username,
                                          int image_index) OVERRIDE;
   virtual void SaveUserImage(const std::string& username,