Reject push registrations when no sender Id has been provided.

content/public/common/push_messaging_status.cc

 // Copyright 2014 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/public/common/push_messaging_status.h"
 
 #include "base/logging.h"
 
 namespace content {
 
 const char* PushRegistrationStatusToString(PushRegistrationStatus status) {
   switch (status) {
     case PUSH_REGISTRATION_STATUS_SUCCESS:
       return "Registration successful";
 
     case PUSH_REGISTRATION_STATUS_NO_SERVICE_WORKER:
       return "Registration failed - no Service Worker";
 
     case PUSH_REGISTRATION_STATUS_SERVICE_NOT_AVAILABLE:
       return "Registration failed - push service not available";
 
     case PUSH_REGISTRATION_STATUS_LIMIT_REACHED:
       return "Registration failed - registration limit has been reached";
 
     case PUSH_REGISTRATION_STATUS_PERMISSION_DENIED:
       return "Registration failed - permission denied";
 
     case PUSH_REGISTRATION_STATUS_SERVICE_ERROR:
       return "Registration failed - push service error";
+
+    case PUSH_REGISTRATION_STATUS_NO_SENDER_ID:
+      return "Registration failed - no sender id provided";
   }
   NOTREACHED();
   return "";
 }
 
 }  // namespace content