Fix a couple of notification TODOs

Delete obsolete notifiations from the database
Stop silently ignoring notifications without an ID

BUG=596161

Review-Url: https://codereview.chromium.org/2671603005
Cr-Commit-Position: refs/heads/master@{#448721}

content/browser/notifications/notification_database.cc

@@ -328,11 +328,6 @@ NotificationDatabase::ReadAllNotificationDataInternal(
       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);
   }
 

content/browser/notifications/platform_notification_context_impl.cc

@@ -252,10 +252,10 @@ void PlatformNotificationContextImpl::
   UMA_HISTOGRAM_ENUMERATION("Notifications.Database.ReadForServiceWorkerResult",
                             status, NotificationDatabase::STATUS_COUNT);
 
+  std::vector<std::string> obsolete_notifications;
+
   if (status == NotificationDatabase::STATUS_OK) {
     if (synchronization_supported) {
-      // Filter out notifications that are not actually on display anymore.
-      // TODO(miguelg) synchronize the database if there are inconsistencies.
       for (auto it = notification_datas.begin();
            it != notification_datas.end();) {
         // The database is only used for persistent notifications.
@@ -264,6 +264,7 @@ void PlatformNotificationContextImpl::
         if (displayed_notifications->count(it->notification_id)) {
           ++it;
         } else {
+          obsolete_notifications.push_back(it->notification_id);
           it = notification_datas.erase(it);
         }
       }
@@ -272,6 +273,10 @@ void PlatformNotificationContextImpl::
     BrowserThread::PostTask(
         BrowserThread::IO, FROM_HERE,
         base::Bind(callback, true /* success */, notification_datas));
+
+    // Remove notifications that are not actually on display anymore.
+    for (const auto& it : obsolete_notifications)
+      database_->DeleteNotificationData(it, origin);
     return;
   }