[WIP] off-main-thread loading

content/renderer/shared_worker/embedded_shared_worker_stub.cc

Index: content/renderer/shared_worker/embedded_shared_worker_stub.cc
diff --git a/content/renderer/shared_worker/embedded_shared_worker_stub.cc b/content/renderer/shared_worker/embedded_shared_worker_stub.cc
index bd42e96545af6e15b611e1290e066b73732cc078..b655adb6c11be2b13d97998965a9e610e8833280 100644
--- a/content/renderer/shared_worker/embedded_shared_worker_stub.cc
+++ b/content/renderer/shared_worker/embedded_shared_worker_stub.cc
@@ -107,6 +107,8 @@ class WebServiceWorkerNetworkProviderImpl
     return kInvalidServiceWorkerVersionId;
   }
 
+  int providerID() override { return provider_->provider_id(); }
+
  private:
   std::unique_ptr<ServiceWorkerNetworkProvider> provider_;
   const bool is_secure_context_;