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

BUG=461282

Review URL: https://codereview.chromium.org/952853002

Cr-Commit-Position: refs/heads/master@{#318666}

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();
 }
@@ -966,6 +970,10 @@ size_t WallpaperManager::GetPendingListSizeForTesting() const {
   return loading_.size();
 }
 
+void WallpaperManager::UserChangedChildStatus(user_manager::User* user) {
+  SetUserWallpaperNow(user->email());
+}
+
 void WallpaperManager::OnDefaultWallpaperDecoded(
     const base::FilePath& path,
     const wallpaper::WallpaperLayout layout,

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

@@ -21,6 +21,7 @@
 #include "chrome/browser/chromeos/settings/cros_settings.h"
 #include "components/user_manager/user.h"
 #include "components/user_manager/user_image/user_image.h"
+#include "components/user_manager/user_manager.h"
 #include "components/wallpaper/wallpaper_layout.h"
 #include "components/wallpaper/wallpaper_manager_base.h"
 #include "content/public/browser/notification_observer.h"
@@ -30,7 +31,9 @@
 
 namespace chromeos {
 
-class WallpaperManager : public wallpaper::WallpaperManagerBase {
+class WallpaperManager :
+    public wallpaper::WallpaperManagerBase,
+    public user_manager::UserManager::UserSessionStateObserver {
  public:
   class PendingWallpaper;
 
@@ -115,6 +118,9 @@ class WallpaperManager : public wallpaper::WallpaperManagerBase {
   // Returns queue size.
   size_t GetPendingListSizeForTesting() const override;
 
+  // Overridden from user_manager::UserManager::UserSessionStateObserver:
+  void UserChangedChildStatus(user_manager::User* user) override;
+
  private:
   friend class TestApi;
   friend class WallpaperManagerBrowserTest;

chrome/browser/ui/ash/multi_user/multi_user_window_manager_chromeos_unittest.cc

@@ -18,10 +18,12 @@
 #include "base/logging.h"
 #include "base/strings/string_util.h"
 #include "base/time/time.h"
+#include "chrome/browser/chromeos/login/users/scoped_user_manager_enabler.h"
 #include "chrome/browser/ui/ash/multi_user/multi_user_window_manager.h"
 #include "chrome/browser/ui/ash/multi_user/multi_user_window_manager_chromeos.h"
 #include "chrome/browser/ui/ash/multi_user/user_switch_animator_chromeos.h"
 #include "chrome/test/base/testing_profile.h"
+#include "components/user_manager/fake_user_manager.h"
 #include "components/user_manager/user_info.h"
 #include "ui/aura/client/aura_constants.h"
 #include "ui/aura/window_event_dispatcher.h"
@@ -39,7 +41,9 @@ class MultiUserWindowManagerChromeOSTest : public AshTestBase {
  public:
   MultiUserWindowManagerChromeOSTest()
       : multi_user_window_manager_(NULL),
-        session_state_delegate_(NULL) {}
+        session_state_delegate_(NULL),
+        fake_user_manager_(new user_manager::FakeUserManager),
+        user_manager_enabler_(fake_user_manager_) {}
 
   void SetUp() override;
   void TearDown() override;
@@ -158,6 +162,10 @@ class MultiUserWindowManagerChromeOSTest : public AshTestBase {
   // The session state delegate.
   ash::test::TestSessionStateDelegate* session_state_delegate_;
 
+  user_manager::FakeUserManager* fake_user_manager_;  // Not owned.
+
+  chromeos::ScopedUserManagerEnabler user_manager_enabler_;
+
   // The maximized window manager (if enabled).
   scoped_ptr<MaximizeModeWindowManager> maximize_mode_window_manager_;