Use a #fefefe solid color wallpaper background before user login for GAIA login flow

chrome/browser/ui/webui/options2/chromeos/set_wallpaper_options_handler2.cc

Index: chrome/browser/ui/webui/options2/chromeos/set_wallpaper_options_handler2.cc
diff --git a/chrome/browser/ui/webui/options2/chromeos/set_wallpaper_options_handler2.cc b/chrome/browser/ui/webui/options2/chromeos/set_wallpaper_options_handler2.cc
index 8c27ac2ed23ebed05212c47fbf2f4760b90a754a..e8b44cb029396f50d10dd5c2ddc81dfbc4135a21 100644
--- a/chrome/browser/ui/webui/options2/chromeos/set_wallpaper_options_handler2.cc
+++ b/chrome/browser/ui/webui/options2/chromeos/set_wallpaper_options_handler2.cc
@@ -219,8 +219,7 @@ void SetWallpaperOptionsHandler::HandleDefaultWallpaper(const ListValue* args) {
   if (IsDefaultWallpaperURL(image_url, &user_image_index)) {
     UserManager::Get()->SaveLoggedInUserWallpaperProperties(User::DEFAULT,
                                                             user_image_index);
-    ash::Shell::GetInstance()->user_wallpaper_delegate()->
-        SetLoggedInUserWallpaper();
+    ash::Shell::GetInstance()->user_wallpaper_delegate()->InitializeWallpaper();
   }
 }