Tray elements behave appropriately on the multiple signin screen (more like lock screen)

chrome/browser/ui/ash/session_state_delegate_views.cc

 // Copyright (c) 2013 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/ui/ash/session_state_delegate_views.h"
 
 #include "ash/session/user_info.h"
 #include "base/logging.h"
 #include "base/strings/string16.h"
 #include "base/strings/utf_string_conversions.h"
@@ skipping 120 matching lines @@
 
 void SessionStateDelegate::AddSessionStateObserver(
     ash::SessionStateObserver* observer) {
   NOTIMPLEMENTED();
 }
 
 void SessionStateDelegate::RemoveSessionStateObserver(
     ash::SessionStateObserver* observer) {
   NOTIMPLEMENTED();
 }
+
+void SessionStateDelegate::HideMultipleSigninScreen() {
+  NOTIMPLEMENTED();
+}