ServiceWorker: Initialize EmbeddedWorkerInstanceClientImpl::wrapper_

content/renderer/service_worker/embedded_worker_instance_client_impl.h

 // Copyright (c) 2016 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.
 
 #ifndef CONTENT_RENDERER_SERVICE_WORKER_EMBEDDED_WORKER_INSTANCE_CLIENT_IMPL_H_
 #define CONTENT_RENDERER_SERVICE_WORKER_EMBEDDED_WORKER_INSTANCE_CLIENT_IMPL_H_
 
 #include "base/id_map.h"
 #include "base/optional.h"
 #include "content/child/child_thread_impl.h"
@@ skipping 45 matching lines @@
 
   // This is valid before StartWorker is called. After that, this object
   // will be passed to ServiceWorkerContextClient.
   std::unique_ptr<EmbeddedWorkerInstanceClientImpl> temporal_self_;
 
   // This is drained by ServiceWorkerContextClient after the worker thread is
   // launched.
   service_manager::mojom::InterfaceProviderRequest renderer_request_;
 
   base::Optional<int> embedded_worker_id_;
-  // Owned by EmbeddedWorkerDispatcher
+
+  // Owned by EmbeddedWorkerDispatcher. This can be nullptr while a worker is
+  // not running.
   EmbeddedWorkerDispatcher::WorkerWrapper* wrapper_;
 
   StopWorkerCallback stop_callback_;
 
   DISALLOW_COPY_AND_ASSIGN(EmbeddedWorkerInstanceClientImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_SERVICE_WORKER_EMBEDDED_WORKER_INSTANCE_CLIENT_IMPL_H_