Teach CrOS's OfflineResourceThrottle about ServiceWorkers so it know longer presents its offline in…

chrome/browser/renderer_host/offline_resource_throttle.h

Index: chrome/browser/renderer_host/offline_resource_throttle.h
diff --git a/chrome/browser/renderer_host/offline_resource_throttle.h b/chrome/browser/renderer_host/offline_resource_throttle.h
index 0d12842d5d2895d88eca59f0b6a2641cbd31f7f0..728421ba83817959a44c8981db9f4a1e44bd4302 100644
--- a/chrome/browser/renderer_host/offline_resource_throttle.h
+++ b/chrome/browser/renderer_host/offline_resource_throttle.h
@@ -51,6 +51,8 @@ class OfflineResourceThrottle
   // Safe to keep a pointer around since AppCacheService outlives all requests.
   content::AppCacheService* appcache_service_;
   net::CancelableCompletionCallback appcache_completion_callback_;
+  net::CancelableCompletionCallback service_worker_completion_callback_;
+  int pending_callbacks_;
 
   DISALLOW_COPY_AND_ASSIGN(OfflineResourceThrottle);
 };