[Merge to M58]Chrome OS: revert the device wallpaper change within a user session.

components/wallpaper/wallpaper_manager_base.h

 // Copyright 2014 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 COMPONENTS_WALLPAPER_WALLPAPER_MANAGER_BASE_H_
 #define COMPONENTS_WALLPAPER_WALLPAPER_MANAGER_BASE_H_
 
 #include <stddef.h>
 
 #include <deque>
@@ skipping 336 matching lines @@
       const GURL& wallpaper_url,
       const base::FilePath& downloaded_file,
       const base::FilePath& resized_directory);
 
   // Returns queue size.
   virtual size_t GetPendingListSizeForTesting() const = 0;
 
   // Ruturns files identifier for the |account_id|.
   virtual WallpaperFilesId GetFilesId(const AccountId& account_id) const = 0;
 
-  // If the device is enterprise managed and we're at the login screen, set the
-  // device wallpaper as the login screen wallpaper. If the device is enterprise
-  // managed and we're in a user session, only set the device wallpaper if there
-  // is no user policy wallpaper and the user hasn't changed the default or the
-  // device wallpaper. Returns true if the device wallpaper should be set as the
-  // wallpaper, otherwise returns false.
+  // If the device is enterprise managed and the device wallpaper policy exists,
+  // set the device wallpaper as the login screen wallpaper.
   virtual bool SetDeviceWallpaperIfApplicable(const AccountId& account_id) = 0;
 
  protected:
   friend class TestApi;
   friend class WallpaperManagerBrowserTest;
   friend class WallpaperManagerBrowserTestDefaultWallpaper;
   friend class WallpaperManagerPolicyTest;
 
   // The |CustomWallpaperElement| contains |first| the path of the image which
   // is currently being loaded and or in progress of being loaded and |second|
@@ skipping 258 matching lines @@
 
   base::WeakPtrFactory<WallpaperManagerBase> weak_factory_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(WallpaperManagerBase);
 };
 
 }  // namespace wallpaper
 
 #endif  // COMPONENTS_WALLPAPER_WALLPAPER_MANAGER_BASE_H_