mash: Migrate some system user files to common.

ash/system/user/tray_user_separator.cc

-// Copyright 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 "ash/system/user/tray_user_separator.h"
-
-#include "ash/common/session/session_state_delegate.h"
-#include "ash/common/wm_shell.h"
-#include "ash/shell.h"
-#include "ui/views/view.h"
-
-namespace ash {
-
-TrayUserSeparator::TrayUserSeparator(SystemTray* system_tray)
-    : SystemTrayItem(system_tray),
-      separator_shown_(false) {
-}
-
-views::View* TrayUserSeparator::CreateTrayView(LoginStatus status) {
-  return NULL;
-}
-
-views::View* TrayUserSeparator::CreateDefaultView(LoginStatus status) {
-  if (status == LoginStatus::NOT_LOGGED_IN)
-    return NULL;
-
-  const SessionStateDelegate* session_state_delegate =
-      Shell::GetInstance()->session_state_delegate();
-
-  // If the screen is locked, a system modal dialog or a single user is shown,
-  // show nothing.
-  if (session_state_delegate->IsUserSessionBlocked() ||
-      WmShell::Get()->IsSystemModalWindowOpen() ||
-      session_state_delegate->NumberOfLoggedInUsers() < 2)
-    return NULL;
-
-  separator_shown_ = true;
-  return new views::View();
-}
-
-views::View* TrayUserSeparator::CreateDetailedView(LoginStatus status) {
-  return NULL;
-}
-
-void TrayUserSeparator::DestroyDefaultView() {
-  separator_shown_ = false;
-}
-
-}  // namespace ash