Wallpaper manager now observing user child user status to update default wallpaper.

chrome/browser/chromeos/login/users/wallpaper/wallpaper_manager.cc

 // 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.
 
 #include "chrome/browser/chromeos/login/users/wallpaper/wallpaper_manager.h"
 
 #include <numeric>
 #include <vector>
 
 #include "ash/ash_constants.h"
@@ skipping 289 matching lines @@
                  chrome::NOTIFICATION_WALLPAPER_ANIMATION_FINISHED,
                  content::NotificationService::AllSources());
   sequence_token_ = BrowserThread::GetBlockingPool()->GetNamedSequenceToken(
       wallpaper::kWallpaperSequenceTokenName);
   task_runner_ = BrowserThread::GetBlockingPool()->
       GetSequencedTaskRunnerWithShutdownBehavior(
           sequence_token_,
           base::SequencedWorkerPool::CONTINUE_ON_SHUTDOWN);
   wallpaper_loader_ = new UserImageLoader(ImageDecoder::ROBUST_JPEG_CODEC,
                                           task_runner_);
+
+  user_manager::UserManager::Get()->AddSessionStateObserver(this);
 }
 
 WallpaperManager::~WallpaperManager() {
   // TODO(bshe): Lifetime of WallpaperManager needs more consideration.
   // http://crbug.com/171694
   DCHECK(!show_user_name_on_signin_subscription_);
 
+  user_manager::UserManager::Get()->RemoveSessionStateObserver(this);
+
   ClearObsoleteWallpaperPrefs();
   weak_factory_.InvalidateWeakPtrs();
 }
 
 WallpaperManager::WallpaperResolution
 WallpaperManager::GetAppropriateResolution() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   gfx::Size size =
       ash::DesktopBackgroundController::GetMaxDisplaySizeInNative();
   return (size.width() > wallpaper::kSmallWallpaperMaxWidth ||
@@ skipping 617 matching lines @@
   }
 
   if (loading_.empty())
     FOR_EACH_OBSERVER(Observer, observers_, OnPendingListEmptyForTesting());
 }
 
 size_t WallpaperManager::GetPendingListSizeForTesting() const {
   return loading_.size();
 }
 
+void WallpaperManager::UserChangedChildStatus(user_manager::User* user) {

[Mr4D (OOO till 08-26), 2015/02/25 15:23:16]

This will probably mess up the user animation. If you look into "
UserSwichAnimatorChromeOS::TransitionWallpaper" you will find the place where
the wallpaper gets changed when switching between users.

I am not entirely sure why this is breaking in your particular case, but there
must be a better way to change this.

[merkulova, 2015/02/25 15:30:14]

It's not change between different users. It's a change that happens inside the
session. When we get an update that user is actually kid account.

+  SetUserWallpaperNow(user->email());
+}
+
 void WallpaperManager::OnDefaultWallpaperDecoded(
     const base::FilePath& path,
     const wallpaper::WallpaperLayout layout,
     scoped_ptr<user_manager::UserImage>* result_out,
     MovableOnDestroyCallbackHolder on_finish,
     const user_manager::UserImage& user_image) {
   result_out->reset(new user_manager::UserImage(user_image));
   ash::Shell::GetInstance()->desktop_background_controller()->SetWallpaperImage(
       user_image.image(), layout);
 }
@@ skipping 53 matching lines @@
     }
   }
 
   if (need_update_screen) {
     DoSetDefaultWallpaper(std::string(),
                           MovableOnDestroyCallbackHolder().Pass());
   }
 }
 
 }  // namespace chromeos