Move all wallpaper file loading and decoding from DesktopBackgroundController to WallpaperManager.

chrome/browser/ui/ash/user_wallpaper_delegate_win.cc

Index: chrome/browser/ui/ash/user_wallpaper_delegate_win.cc
diff --git a/chrome/browser/ui/ash/user_wallpaper_delegate_win.cc b/chrome/browser/ui/ash/user_wallpaper_delegate_win.cc
index c058b59c0e520460a423f67d73b7d7c232a7a96b..e080c9389a8f4eaac68002e4647ba7d9c23de121 100644
--- a/chrome/browser/ui/ash/user_wallpaper_delegate_win.cc
+++ b/chrome/browser/ui/ash/user_wallpaper_delegate_win.cc
@@ -58,8 +58,8 @@ class UserWallpaperDelegate : public ash::UserWallpaperDelegate {
     }
 #endif
     gfx::ImageSkia wallpaper = gfx::ImageSkia::CreateFrom1xBitmap(bitmap);
-    ash::Shell::GetInstance()->desktop_background_controller()->
-        SetCustomWallpaper(wallpaper, ash::WALLPAPER_LAYOUT_TILE);
+    ash::Shell::GetInstance()->desktop_background_controller()->SetWallpaper(
+        wallpaper, ash::WALLPAPER_LAYOUT_TILE);
   }
 
   virtual void InitializeWallpaper() OVERRIDE {