Add a test of updating cached height for popup notifications

ash/system/web_notification/web_notification_tray.cc

 // Copyright (c) 2012 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/web_notification/web_notification_tray.h"
 
 #include "ash/ash_switches.h"
 #include "ash/root_window_controller.h"
 #include "ash/shelf/shelf_layout_manager.h"
 #include "ash/shelf/shelf_layout_manager_observer.h"
@@ skipping 268 matching lines @@
   show_message_center_on_unlock_ = false;
   status_area_widget()->SetHideSystemNotifications(false);
   GetShelfLayoutManager()->UpdateAutoHideState();
   button_->SetBubbleVisible(false);
 }
 
 void WebNotificationTray::SetSystemTrayHeight(int height) {
   popup_alignment_delegate_->SetSystemTrayHeight(height);
 }
 
+int WebNotificationTray::system_tray_height() const {
+  return popup_alignment_delegate_->system_tray_height();
+}
+
 bool WebNotificationTray::ShowPopups() {
   if (message_center_bubble())
     return false;
 
   popup_collection_->DoUpdateIfPossible();
   return true;
 }
 
 void WebNotificationTray::HidePopups() {
   DCHECK(popup_collection_.get());
@@ skipping 205 matching lines @@
 
 message_center::MessageCenterBubble*
 WebNotificationTray::GetMessageCenterBubbleForTest() {
   if (!message_center_bubble())
     return NULL;
   return static_cast<message_center::MessageCenterBubble*>(
       message_center_bubble()->bubble());
 }
 
 }  // namespace ash