Remove a renderer -> browser roundtrip for resolving the showNotification promise.

content/common/platform_notification_messages.h

 // Copyright 2014 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.
 
 // Messages for platform-native notifications using the Web Notification API.
 // Multiply-included message file, hence no include guard.
 
 #include "content/public/common/platform_notification_data.h"
 #include "ipc/ipc_message_macros.h"
 #include "third_party/WebKit/public/platform/WebNotificationPermission.h"
@@ skipping 12 matching lines @@
   IPC_STRUCT_TRAITS_MEMBER(title)
   IPC_STRUCT_TRAITS_MEMBER(direction)
   IPC_STRUCT_TRAITS_MEMBER(lang)
   IPC_STRUCT_TRAITS_MEMBER(body)
   IPC_STRUCT_TRAITS_MEMBER(tag)
   IPC_STRUCT_TRAITS_MEMBER(icon)
 IPC_STRUCT_TRAITS_END()
 
 // Messages sent from the browser to the renderer.
 
-// Informs the renderer that the browser has displayed the persistent
-// notification.
-IPC_MESSAGE_CONTROL1(PlatformNotificationMsg_DidShowPersistent,
-                     int /* request_id */)
-
 // Informs the renderer that the browser has displayed the notification.
 IPC_MESSAGE_CONTROL1(PlatformNotificationMsg_DidShow,
                      int /* notification_id */)
 
 // Informs the renderer that the notification has been closed.
 IPC_MESSAGE_CONTROL1(PlatformNotificationMsg_DidClose,
                      int /* notification_id */)
 
 // Informs the renderer that the notification has been clicked on.
 IPC_MESSAGE_CONTROL1(PlatformNotificationMsg_DidClick,
                      int /* notification_id */)
 
 // Messages sent from the renderer to the browser.
 
 IPC_MESSAGE_CONTROL4(PlatformNotificationHostMsg_Show,
                      int /* notification_id */,
                      GURL /* origin */,
                      SkBitmap /* icon */,
                      content::PlatformNotificationData /* notification_data */)
 
-IPC_MESSAGE_CONTROL5(PlatformNotificationHostMsg_ShowPersistent,
-                     int /* request_id */,
+IPC_MESSAGE_CONTROL4(PlatformNotificationHostMsg_ShowPersistent,
                      int64 /* service_worker_provider_id */,
                      GURL /* origin */,
                      SkBitmap /* icon */,
                      content::PlatformNotificationData /* notification_data */)
 
 IPC_MESSAGE_CONTROL1(PlatformNotificationHostMsg_Close,
                      int /* notification_id */)
 
 IPC_MESSAGE_CONTROL1(PlatformNotificationHostMsg_ClosePersistent,
                      std::string /* persistent_notification_id */)
 
 IPC_SYNC_MESSAGE_CONTROL1_1(PlatformNotificationHostMsg_CheckPermission,
                             GURL /* origin */,
                             blink::WebNotificationPermission /* result */)