Fix the crash in DesktopBackgroundView::OnPaint

chrome/browser/chromeos/login/wallpaper_manager.h

 // 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.
 
 #ifndef CHROME_BROWSER_CHROMEOS_LOGIN_WALLPAPER_MANAGER_H_
 #define CHROME_BROWSER_CHROMEOS_LOGIN_WALLPAPER_MANAGER_H_
 
 #include <string>
 
 #include "ash/desktop_background/desktop_background_resources.h"
@@ skipping 247 matching lines @@
   void OnWallpaperDecoded(const std::string& email,
                           ash::WallpaperLayout layout,
                           bool update_wallpaper,
                           const UserImage& wallpaper);
 
   // Saves encoded wallpaper to |path|. This callback is called after encoding
   // to PNG completes.
   void OnWallpaperEncoded(const FilePath& path,
                           scoped_refptr<base::RefCountedBytes> data);
 
+  // Generates thumbnail of custom wallpaper on FILE thread. If |persistent| is
+  // true, saves original custom image and resized images to disk.
+  void ProcessCustomWallpaper(const std::string& email,
+                              bool persistent,
+                              const WallpaperInfo& info,
+                              base::WeakPtr<WallpaperDelegate> delegate,
+                              scoped_ptr<gfx::ImageSkia> image,
+                              const UserImage::RawImage& raw_image);
+
   // Record data for User Metrics Analysis.
   void RecordUma(User::WallpaperType type, int index);
 
   // Saves original custom wallpaper to |path| (absolute path) on filesystem
   // and starts resizing operation of the custom wallpaper if necessary.
   void SaveCustomWallpaper(const std::string& email,
                            const FilePath& path,
                            ash::WallpaperLayout layout,
                            const UserImage& wallpaper);
 
@@ skipping 60 matching lines @@
   content::NotificationRegistrar registrar_;
 
   base::OneShotTimer<WallpaperManager> timer_;
 
   DISALLOW_COPY_AND_ASSIGN(WallpaperManager);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_LOGIN_WALLPAPER_MANAGER_H_