Revert of This CL replaces user_manager::UserID with AccountId.

chrome/browser/chromeos/login/users/wallpaper/wallpaper_manager.cc

Index: chrome/browser/chromeos/login/users/wallpaper/wallpaper_manager.cc
diff --git a/chrome/browser/chromeos/login/users/wallpaper/wallpaper_manager.cc b/chrome/browser/chromeos/login/users/wallpaper/wallpaper_manager.cc
index 4b8f6c8d2620135571290f0d9a83e5a82ae5c326..cf3d3afc669cfc76fd59a283f8ee6c6da014bbf5 100644
--- a/chrome/browser/chromeos/login/users/wallpaper/wallpaper_manager.cc
+++ b/chrome/browser/chromeos/login/users/wallpaper/wallpaper_manager.cc
@@ -478,12 +478,12 @@
     return;
   }
 
-  const user_manager::User* user = user_manager::UserManager::Get()->FindUser(
-      AccountId::FromUserEmail(user_id));
+  const user_manager::User* user =
+      user_manager::UserManager::Get()->FindUser(user_id);
   CHECK(user);
-  const bool is_persistent =
+  bool is_persistent =
       !user_manager::UserManager::Get()->IsUserNonCryptohomeDataEphemeral(
-          AccountId::FromUserEmail(user_id)) ||
+          user_id) ||
       (type == user_manager::User::POLICY &&
        user->GetType() == user_manager::USER_TYPE_PUBLIC_ACCOUNT);
 
@@ -556,8 +556,8 @@
 
   const base::FilePath* file = NULL;
 
-  const user_manager::User* user = user_manager::UserManager::Get()->FindUser(
-      AccountId::FromUserEmail(user_id));
+  const user_manager::User* user =
+      user_manager::UserManager::Get()->FindUser(user_id);
 
   if (user_manager::UserManager::Get()->IsLoggedInAsGuest()) {
     file =
@@ -624,9 +624,8 @@
     return;
   }
 
-  const AccountId account_id = AccountId::FromUserEmail(user_id);
   const user_manager::User* user =
-      user_manager::UserManager::Get()->FindUser(account_id);
+      user_manager::UserManager::Get()->FindUser(user_id);
 
   // User is unknown or there is no visible background in kiosk mode.
   if (!user || user->GetType() == user_manager::USER_TYPE_KIOSK_APP)
@@ -634,7 +633,7 @@
 
   // Guest user or regular user in ephemeral mode.
   if ((user_manager::UserManager::Get()->IsUserNonCryptohomeDataEphemeral(
-           account_id) &&
+           user_id) &&
        user->HasGaiaAccount()) ||
       user->GetType() == user_manager::USER_TYPE_GUEST) {
     InitInitialUserWallpaper(user_id, false);
@@ -811,7 +810,7 @@
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
 
   if (user_manager::UserManager::Get()->IsUserNonCryptohomeDataEphemeral(
-          AccountId::FromUserEmail(user_id))) {
+          user_id)) {
     // Default to the values cached in memory.
     *info = current_user_wallpaper_info_;