Hide notification tray when the user flow doesn't allow

ash/common/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/common/system/web_notification/web_notification_tray.h"
 
 #include "ash/common/material_design/material_design_controller.h"
 #include "ash/common/session/session_state_delegate.h"
 #include "ash/common/shelf/shelf_constants.h"
 #include "ash/common/shelf/wm_shelf.h"
@@ skipping 618 matching lines @@
       visible_notification_count - visible_small_icon_count;
   if (hidden_icon_count != 0) {
     counter_->SetVisible(true);
     counter_->SetNotificationCount(
         (visible_small_icon_count != 0),  // small_icons_exist
         hidden_icon_count);
   } else {
     counter_->SetVisible(false);
   }
 
-  SetVisible(IsLoggedIn());
+  SetVisible(IsLoggedIn() && ShouldShowMessageCenter());
   PreferredSizeChanged();
   Layout();
   SchedulePaint();
   if (IsLoggedIn())
     system_tray_->SetNextFocusableView(this);
 }
 
 void WebNotificationTray::ClickedOutsideBubble() {
   // Only hide the message center
   if (!message_center_bubble())
@@ skipping 21 matching lines @@
 
 message_center::MessageCenterBubble*
 WebNotificationTray::GetMessageCenterBubbleForTest() {
   if (!message_center_bubble())
     return nullptr;
   return static_cast<message_center::MessageCenterBubble*>(
       message_center_bubble()->bubble());
 }
 
 }  // namespace ash