Service Worker: Add metrics and timeout for starting a Service Worker.

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 {
 
@@ skipping 21 matching lines @@
       return "IPC connection was closed or IPC error has occured";
     case SERVICE_WORKER_ERROR_NETWORK:
       return "Operation failed by network issue";
     case SERVICE_WORKER_ERROR_SECURITY:
       return "Operation failed by security issue";
     case SERVICE_WORKER_ERROR_EVENT_WAITUNTIL_REJECTED:
       return "ServiceWorker failed to handle event (event.waitUntil "
              "Promise rejected)";
     case SERVICE_WORKER_ERROR_STATE:
       return "The ServiceWorker state was not valid";
+    case SERVICE_WORKER_ERROR_TIMEOUT:
+      return "The ServiceWorker timed out";
+    case SERVICE_WORKER_ERROR_MAX_VALUE:
+      NOTREACHED();
   }
   NOTREACHED();
   return "";
 }
 
 }  // namespace content