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

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

Index: chrome/browser/chromeos/login/users/wallpaper/wallpaper_manager.cc
diff --git a/chrome/browser/chromeos/login/users/wallpaper/wallpaper_manager.cc b/chrome/browser/chromeos/login/users/wallpaper/wallpaper_manager.cc
index a65d9797f6713dcb4d24887d818f9b488815de95..589a1570795d4d3689bfbdc9af13bfb13de07261 100644
--- a/chrome/browser/chromeos/login/users/wallpaper/wallpaper_manager.cc
+++ b/chrome/browser/chromeos/login/users/wallpaper/wallpaper_manager.cc
@@ -307,6 +307,8 @@ WallpaperManager::WallpaperManager()
           base::SequencedWorkerPool::CONTINUE_ON_SHUTDOWN);
   wallpaper_loader_ = new UserImageLoader(ImageDecoder::ROBUST_JPEG_CODEC,
                                           task_runner_);
+
+  user_manager::UserManager::Get()->AddSessionStateObserver(this);
 }
 
 WallpaperManager::~WallpaperManager() {
@@ -314,6 +316,8 @@ WallpaperManager::~WallpaperManager() {
   // http://crbug.com/171694
   DCHECK(!show_user_name_on_signin_subscription_);
 
+  user_manager::UserManager::Get()->RemoveSessionStateObserver(this);
+
   ClearObsoleteWallpaperPrefs();
   weak_factory_.InvalidateWeakPtrs();
 }
@@ -951,6 +955,10 @@ 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,