Hide the settings button on a notification in MNC.

ui/arc/notification/arc_notification_manager.cc

 // Copyright 2016 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 "ui/arc/notification/arc_notification_manager.h"
 
 #include <memory>
 #include <utility>
 
 #include "ash/common/system/toast/toast_manager.h"
@@ skipping 222 matching lines @@
   auto* notifications_instance = ARC_GET_INSTANCE_FOR_METHOD(
       arc_bridge_service()->notifications(), OpenNotificationSettings);
 
   // On shutdown, the ARC channel may quit earlier than notifications.
   if (!notifications_instance)
     return;
 
   notifications_instance->OpenNotificationSettings(key);
 }
 
+bool ArcNotificationManager::IsOpeningSettingsSupported() const {
+  const auto* notifications_instance = ARC_GET_INSTANCE_FOR_METHOD(
+      arc_bridge_service()->notifications(), OpenNotificationSettings);
+  return notifications_instance != nullptr;
+}
+
 void ArcNotificationManager::OnToastPosted(mojom::ArcToastDataPtr data) {
   const base::string16 text16(
       base::UTF8ToUTF16(data->text.has_value() ? *data->text : std::string()));
   const base::string16 dismiss_text16(base::UTF8ToUTF16(
       data->dismiss_text.has_value() ? *data->dismiss_text : std::string()));
   ash::Shell::GetInstance()->toast_manager()->Show(
       ash::ToastData(data->id, text16, data->duration, dismiss_text16));
 }
 
 void ArcNotificationManager::OnToastCancelled(mojom::ArcToastDataPtr data) {
   ash::Shell::GetInstance()->toast_manager()->Cancel(data->id);
 }
 
 }  // namespace arc