ServiceWorker: Change worker script fetch error code(1/3).

Source/modules/serviceworkers/ServiceWorkerError.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 37 matching lines @@
         return DOMException::create(AbortError, "The Service Worker operation was aborted.");
     case WebServiceWorkerError::ErrorTypeSecurity:
         return DOMException::create(SecurityError, "The Service Worker security policy prevented an action.");
     case WebServiceWorkerError::ErrorTypeInstall:
         // FIXME: Introduce new InstallError type to ExceptionCodes?
         return DOMException::create(AbortError, "The Service Worker installation failed.");
     case WebServiceWorkerError::ErrorTypeActivate:
         // Not currently returned as a promise rejection.
         // FIXME: Introduce new ActivateError type to ExceptionCodes?
         return DOMException::create(AbortError, "The Service Worker activation failed.");
+    case WebServiceWorkerError::ErrorTypeNetwork:
+        return DOMException::create(NetworkError, "The Service Worker failed by network.");
     case WebServiceWorkerError::ErrorTypeNotFound:
         return DOMException::create(NotFoundError, "The specified Service Worker resource was not found.");
     case WebServiceWorkerError::ErrorTypeUnknown:
         return DOMException::create(UnknownError, "An unknown error occurred within Service Worker.");
     }
     ASSERT_NOT_REACHED();
     return DOMException::create(UnknownError);
 }
 
 // static
 void ServiceWorkerError::dispose(WebType* webErrorRaw)
 {
     delete webErrorRaw;
 }
 
 } // namespace blink