NTP4: remove unused promo C++

chrome/browser/chrome_notification_types.h

Index: chrome/browser/chrome_notification_types.h
diff --git a/chrome/browser/chrome_notification_types.h b/chrome/browser/chrome_notification_types.h
index 0b1e2dd10546bd233bde6a6b288d31891bdd3e95..cf093ce6d2d1b44a689a3b734a0766cdae0e93ec 100644
--- a/chrome/browser/chrome_notification_types.h
+++ b/chrome/browser/chrome_notification_types.h
@@ -251,11 +251,6 @@ enum NotificationType {
 
   // Non-history storage services --------------------------------------------
 
-  // The state of a web resource has been changed. A resource may have been
-  // added, removed, or altered. Source is WebResourceService, and the
-  // details are NoDetails.
-  NOTIFICATION_PROMO_RESOURCE_STATE_CHANGED,
-
   // A safe browsing database update completed.  Source is the
   // SafeBrowsingService and the details are a bool indicating whether the
   // update was successful.