Allow partial update for notification update API

chrome/browser/notifications/notification_ui_manager_impl.cc

Index: chrome/browser/notifications/notification_ui_manager_impl.cc
diff --git a/chrome/browser/notifications/notification_ui_manager_impl.cc b/chrome/browser/notifications/notification_ui_manager_impl.cc
index 6e15592f004e9a36938be8c9c0a3a76d3bdcf316..9b65dd5a88905a62ccaa5a0bb9a7812b29a83c9f 100644
--- a/chrome/browser/notifications/notification_ui_manager_impl.cc
+++ b/chrome/browser/notifications/notification_ui_manager_impl.cc
@@ -74,11 +74,15 @@ void NotificationUIManagerImpl::Add(const Notification& notification,
   CheckAndShowNotifications();
 }
 
-bool NotificationUIManagerImpl::DoesIdExist(const std::string& id) {
+bool NotificationUIManagerImpl::DoesIdExist(
+    const std::string& id, Notification* matched_notification) {
   for (NotificationDeque::iterator iter = show_queue_.begin();
        iter != show_queue_.end(); ++iter) {
-    if ((*iter)->notification().notification_id() == id)
+    if ((*iter)->notification().notification_id() == id) {
+      if (matched_notification)
+        *matched_notification = (*iter)->notification();
       return true;
+    }
   }
   return false;
 }