Modal window in user session not blocks user adding screen.

chrome/browser/ui/ash/session_state_delegate_views.cc

Index: chrome/browser/ui/ash/session_state_delegate_views.cc
diff --git a/chrome/browser/ui/ash/session_state_delegate_views.cc b/chrome/browser/ui/ash/session_state_delegate_views.cc
index d649ff316b21c7814a57430da101c341717206d9..a1389ca8546677a6788cae63aff0c8288cb12a5c 100644
--- a/chrome/browser/ui/ash/session_state_delegate_views.cc
+++ b/chrome/browser/ui/ash/session_state_delegate_views.cc
@@ -46,6 +46,10 @@ void SessionStateDelegate::LockScreen() {
 void SessionStateDelegate::UnlockScreen() {
 }
 
+bool SessionStateDelegate::IsUserSessionBlocked() const {
+  return false;
+}
+
 const base::string16 SessionStateDelegate::GetUserDisplayName(
     ash::MultiProfileIndex index) const {
   NOTIMPLEMENTED();