[proof-of-concept] SW thread independent of the main thread

content/child/service_worker/service_worker_registration_handle_reference.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/child/service_worker/service_worker_registration_handle_reference.h"
 
 #include "base/memory/ptr_util.h"
 #include "content/child/thread_safe_sender.h"
 #include "content/common/service_worker/service_worker_messages.h"
 
@@ skipping 19 matching lines @@
 ServiceWorkerRegistrationHandleReference(
     const ServiceWorkerRegistrationObjectInfo& info,
     ThreadSafeSender* sender,
     bool increment_ref_in_ctor)
     : info_(info),
       sender_(sender) {
   DCHECK_NE(kInvalidServiceWorkerRegistrationHandleId, info_.handle_id);
   DCHECK(sender_.get());
   if (!increment_ref_in_ctor)
     return;
+  if (!sender_)
+    return;
   sender_->Send(
       new ServiceWorkerHostMsg_IncrementRegistrationRefCount(info_.handle_id));
 }
 
 ServiceWorkerRegistrationHandleReference::
 ~ServiceWorkerRegistrationHandleReference() {
+  if (!sender_)
+    return;
   sender_->Send(
       new ServiceWorkerHostMsg_DecrementRegistrationRefCount(info_.handle_id));
 }
 
 }  // namespace content