Add support for native extension notifications

chrome/browser/notifications/non_persistent_notification_handler.cc

Index: chrome/browser/notifications/non_persistent_notification_handler.cc
diff --git a/chrome/browser/notifications/non_persistent_notification_handler.cc b/chrome/browser/notifications/non_persistent_notification_handler.cc
index 6222cd2fd94a227cdc02c548dd2e878e0c6739fe..e40b79ce2ff3b8c0a604be79cc1ecda96a1f5d79 100644
--- a/chrome/browser/notifications/non_persistent_notification_handler.cc
+++ b/chrome/browser/notifications/non_persistent_notification_handler.cc
@@ -8,8 +8,8 @@
 #include "chrome/browser/notifications/notification_delegate.h"
 #include "chrome/browser/notifications/platform_notification_service_impl.h"
 
-NonPersistentNotificationHandler::NonPersistentNotificationHandler() {}
-NonPersistentNotificationHandler::~NonPersistentNotificationHandler() {}
+NonPersistentNotificationHandler::NonPersistentNotificationHandler() = default;
+NonPersistentNotificationHandler::~NonPersistentNotificationHandler() = default;
 
 void NonPersistentNotificationHandler::OnClose(
     Profile* profile,
@@ -28,8 +28,6 @@ void NonPersistentNotificationHandler::OnClick(
     const std::string& notification_id,
     int action_index,
     const base::NullableString16& reply) {
-  // Buttons and replies not supported for non persistent notifications.
-  DCHECK_EQ(action_index, -1);
   DCHECK(reply.is_null());
 
   if (notifications_.find(notification_id) != notifications_.end()) {