cros: Move wallpaper after login screen is gone

chrome/browser/chromeos/login/ui/login_display_host_impl.h

Index: chrome/browser/chromeos/login/ui/login_display_host_impl.h
diff --git a/chrome/browser/chromeos/login/ui/login_display_host_impl.h b/chrome/browser/chromeos/login/ui/login_display_host_impl.h
index 124f21f3bc2d5276405378477ef2abb107fe996e..931f65a4419fbd77a2c40456f26676db75e40ae7 100644
--- a/chrome/browser/chromeos/login/ui/login_display_host_impl.h
+++ b/chrome/browser/chromeos/login/ui/login_display_host_impl.h
@@ -63,13 +63,13 @@ class LoginDisplayHostImpl : public LoginDisplayHost,
   OobeUI* GetOobeUI() const override;
   WebUILoginView* GetWebUILoginView() const override;
   void BeforeSessionStart() override;
-  void Finalize() override;
+  void Finalize(base::OnceClosure completion_callback) override;
   void OpenProxySettings() override;
   void SetStatusAreaVisible(bool visible) override;
   void StartWizard(OobeScreen first_screen) override;
   WizardController* GetWizardController() override;
   AppLaunchController* GetAppLaunchController() override;
-  void StartUserAdding(const base::Closure& completion_callback) override;
+  void StartUserAdding(base::OnceClosure completion_callback) override;
   void CancelUserAdding() override;
   void StartSignInScreen(const LoginScreenContext& context) override;
   void OnPreferencesChanged() override;
@@ -270,8 +270,8 @@ class LoginDisplayHostImpl : public LoginDisplayHost,
   // Stored parameters for StartWizard, required to restore in case of crash.
   OobeScreen first_screen_;
 
-  // Called before host deletion.
-  base::Closure completion_callback_;
+  // Called after host deletion.
+  std::vector<base::OnceClosure> completion_callbacks_;
 
   // Active instance of authentication prewarmer.
   std::unique_ptr<AuthPrewarmer> auth_prewarmer_;