RE-add the ability to delete notification ids unknown by the display service.

content/browser/notifications/notification_database.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 "content/browser/notifications/notification_database.h"
 
 #include <string>
 
 #include "base/files/file_util.h"
 #include "base/strings/string_number_conversions.h"
@@ skipping 310 matching lines @@
                                                  &notification_database_data);
     if (status != STATUS_OK)
       return status;
 
     if (service_worker_registration_id != kInvalidServiceWorkerRegistrationId &&
         notification_database_data.service_worker_registration_id !=
             service_worker_registration_id) {
       continue;
     }
 
-    // Silently ignore the notification if it doesn't have an ID assigned.
-    // TODO(peter): Remove this clause when Chrome 55 has branched.
-    if (notification_database_data.notification_id.empty())
-      continue;
-
     notification_data_vector->push_back(notification_database_data);
   }
 
   return LevelDBStatusToStatus(iter->status());
 }
 
 NotificationDatabase::Status
 NotificationDatabase::DeleteAllNotificationDataInternal(
     const GURL& origin,
     const std::string& tag,
@@ skipping 42 matching lines @@
         notification_database_data.notification_id);
   }
 
   if (deleted_notification_ids->empty())
     return STATUS_OK;
 
   return LevelDBStatusToStatus(db_->Write(leveldb::WriteOptions(), &batch));
 }
 
 }  // namespace content