Refine error code returned by ServiceWorkerVersion::StartWorker (e.g. PROCESS_NOT_FOUND etc)

content/common/service_worker/service_worker_status_code.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/common/service_worker/service_worker_status_code.h"
 
 #include "base/logging.h"
 
 namespace content {
 
 const char* ServiceWorkerStatusToString(ServiceWorkerStatusCode status) {
   switch (status) {
     case SERVICE_WORKER_OK:
       return "Operation has succeeded";
     case SERVICE_WORKER_ERROR_FAILED:
       return "Operation has failed (unknown reason)";
     case SERVICE_WORKER_ERROR_ABORT:
       return "Operation has been aborted";
     case SERVICE_WORKER_ERROR_PROCESS_NOT_FOUND:
       return "Could not find a renderer process to run a service worker";
     case SERVICE_WORKER_ERROR_START_WORKER_FAILED:
       return "ServiceWorker cannot be started";
     case SERVICE_WORKER_ERROR_INSTALL_WORKER_FAILED:
       return "ServiceWorker failed to install";
     case SERVICE_WORKER_ERROR_ACTIVATE_WORKER_FAILED:
       return "ServiceWorker failed to activate";
+    case SERVICE_WORKER_ERROR_IPC_FAILED:
+      return "IPC connection was closed or IPC error has occured";
   }
   NOTREACHED();
   return "";
 }
 
 }  // namespace content