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

chrome/browser/chromeos/login/user_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_USER_MANAGER_H_
 #define CHROME_BROWSER_CHROMEOS_LOGIN_USER_MANAGER_H_
 #pragma once
 
 #include <string>
 
@@ skipping 83 matching lines @@
 
   // Indicates that user just logged on as the demo user.
   virtual void DemoUserLoggedIn() = 0;
 
   // Indicates that user just started incognito session.
   virtual void GuestUserLoggedIn() = 0;
 
   // Indicates that a user just logged in as ephemeral.
   virtual void EphemeralUserLoggedIn(const std::string& email) = 0;
 
-  // Loads logged in user wallpaper asynchronously and sets to current wallpaper
-  // after loaded. If not logged in or logged in as stub user, uses an empty
-  // wallpaper.
-  virtual void SetLoggedInUserWallpaper() = 0;
+  // Initalize wallpaper. If logged in, load user's wallpaper. If not logged in
+  // or logged in as stub user, uses an empty wallpaper or a solid color
+  // wallpaper when GAIA login flow.
+  virtual void InitializeWallpaper() = 0;
 
   // Called when user pod with |email| is selected.
   virtual void UserSelected(const std::string& email) = 0;
 
   // Called when browser session is started i.e. after
   // browser_creator.LaunchBrowser(...) was called after user sign in.
   // When user is at the image screen IsUserLoggedIn() will return true
   // but SessionStarted() will return false.
   // Fires NOTIFICATION_SESSION_STARTED.
   virtual void SessionStarted() = 0;
@@ skipping 121 matching lines @@
   virtual void NotifyLocalStateChanged() = 0;
 
   // Returns the result of the last successful profile image download, if any.
   // Otherwise, returns an empty bitmap.
   virtual const SkBitmap& DownloadedProfileImage() const = 0;
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_LOGIN_USER_MANAGER_H_