Automatically close the default push notification when a real one appears.

chrome/browser/push_messaging/push_messaging_notification_manager.cc

 // Copyright 2015 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 "chrome/browser/push_messaging/push_messaging_notification_manager.h"
 
 #include <bitset>
 
 #include "base/metrics/histogram_macros.h"
 #include "base/strings/utf_string_conversions.h"
@@ skipping 131 matching lines @@
     if (requesting_origin == active_url.GetOrigin()) {
       notification_needed = false;
       break;
     }
 #if defined(OS_ANDROID)
   }
 #else
   }
 #endif
 
+  // If more than two notifications are showing for this Service Worker, close
+  // the default notification if it happens to be part of this group.
+  if (notification_count >= 2) {
+    for (const auto& notification_database_data : data) {
+      if (notification_database_data.notification_data.tag !=
+          kPushMessagingForcedNotificationTag)
+        continue;
+
+      PlatformNotificationServiceImpl* platform_notification_service =
+          PlatformNotificationServiceImpl::GetInstance();
+
+      // First close the notification for the user's point of view, and then
+      // manually tell the service that the notification has been closed in
+      // order to avoid duplicating the thread-jump logic.
+      platform_notification_service->ClosePersistentNotification(
+          profile_, notification_database_data.notification_id);
+      platform_notification_service->OnPersistentNotificationClose(
+          profile_, notification_database_data.notification_id,
+          notification_database_data.origin);
+
+      break;
+    }
+  }
+
   // Don't track push messages that didn't show a notification but were exempt
   // from needing to do so.
   if (notification_shown || notification_needed) {
     content::ServiceWorkerContext* service_worker_context =
         content::BrowserContext::GetStoragePartitionForSite(
             profile_, requesting_origin)->GetServiceWorkerContext();
 
     content::PushMessagingService::GetNotificationsShownByLastFewPushes(
         service_worker_context, service_worker_registration_id,
         base::Bind(&PushMessagingNotificationManager
@@ skipping 132 matching lines @@
     return;
   }
   PlatformNotificationServiceImpl::GetInstance()->DisplayPersistentNotification(
       profile_,
       persistent_notification_id,
       requesting_origin,
       SkBitmap() /* icon */,
       notification_data);
   message_handled_closure.Run();
 }