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

content/child/service_worker/web_service_worker_registration_impl.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/web_service_worker_registration_impl.h"
 
 #include <utility>
 
 #include "base/macros.h"
 #include "base/memory/ptr_util.h"
@@ skipping 39 matching lines @@
 
 WebServiceWorkerRegistrationImpl::WebServiceWorkerRegistrationImpl(
     std::unique_ptr<ServiceWorkerRegistrationHandleReference> handle_ref)
     : handle_ref_(std::move(handle_ref)), proxy_(nullptr) {
   DCHECK(handle_ref_);
   DCHECK_NE(kInvalidServiceWorkerRegistrationHandleId,
             handle_ref_->handle_id());
   ServiceWorkerDispatcher* dispatcher =
       ServiceWorkerDispatcher::GetThreadSpecificInstance();
   DCHECK(dispatcher);
+  if (!dispatcher)
+    return;
   dispatcher->AddServiceWorkerRegistration(handle_ref_->handle_id(), this);
 }
 
 void WebServiceWorkerRegistrationImpl::SetInstalling(
     const scoped_refptr<WebServiceWorkerImpl>& service_worker) {
   if (proxy_)
     proxy_->setInstalling(WebServiceWorkerImpl::CreateHandle(service_worker));
   else
     queued_tasks_.push_back(QueuedTask(INSTALLING, service_worker));
 }
@@ skipping 97 matching lines @@
 }
 
 WebServiceWorkerRegistrationImpl::~WebServiceWorkerRegistrationImpl() {
   ServiceWorkerDispatcher* dispatcher =
       ServiceWorkerDispatcher::GetThreadSpecificInstance();
   if (dispatcher)
     dispatcher->RemoveServiceWorkerRegistration(handle_ref_->handle_id());
 }
 
 }  // namespace content