Remove use of index in wallpaper picker code and some refactor

chrome/browser/chromeos/login/webui_login_display.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 "chrome/browser/chromeos/login/webui_login_display.h"
 
 #include "chrome/browser/chromeos/accessibility/accessibility_util.h"
 #include "chrome/browser/chromeos/input_method/input_method_manager.h"
 #include "chrome/browser/chromeos/input_method/xkeyboard.h"
 #include "chrome/browser/chromeos/login/screen_locker.h"
@@ skipping 209 matching lines @@
   DCHECK(delegate_);
   if (delegate_)
     delegate_->CreateAccount();
 }
 
 void WebUILoginDisplay::LoadWallpaper(const std::string& username) {
   WallpaperManager::Get()->SetUserWallpaper(username);
 }
 
 void WebUILoginDisplay::LoadSigninWallpaper() {
-  WallpaperManager::Get()->SetSigninWallpaper();
+  WallpaperManager::Get()->SetDefaultWallpaper();
 }
 
 void WebUILoginDisplay::RemoveUser(const std::string& username) {
   UserManager::Get()->RemoveUser(username, this);
 }
 
 void WebUILoginDisplay::ShowEnterpriseEnrollmentScreen() {
   if (delegate_)
     delegate_->OnStartEnterpriseEnrollment();
 }
@@ skipping 30 matching lines @@
 bool WebUILoginDisplay::IsShowNewUser() const {
   return show_new_user_;
 }
 
 void WebUILoginDisplay::SetDisplayEmail(const std::string& email) {
   if (delegate_)
     delegate_->SetDisplayEmail(email);
 }
 
 }  // namespace chromeos