Check the existence of SWContext in DidUpdateNavigationPreloadEnabled/Hexistence

content/browser/service_worker/service_worker_dispatcher_host.cc

 // Copyright 2013 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/browser/service_worker/service_worker_dispatcher_host.h"
 
 #include <utility>
 
 #include "base/debug/crash_logging.h"
 #include "base/logging.h"
@@ skipping 1534 matching lines @@
     int registration_id,
     bool enable,
     ServiceWorkerStatusCode status) {
   if (status != SERVICE_WORKER_OK) {
     Send(new ServiceWorkerMsg_EnableNavigationPreloadError(
         thread_id, request_id, WebServiceWorkerError::kErrorTypeUnknown,
         std::string(kEnableNavigationPreloadErrorPrefix) +
             std::string(kDatabaseErrorMessage)));
     return;
   }
+  if (!GetContext())
+    return;
   ServiceWorkerRegistration* registration =
       GetContext()->GetLiveRegistration(registration_id);
   if (registration)
     registration->EnableNavigationPreload(enable);
   Send(new ServiceWorkerMsg_DidEnableNavigationPreload(thread_id, request_id));
 }
 
 void ServiceWorkerDispatcherHost::DidUpdateNavigationPreloadHeader(
     int thread_id,
     int request_id,
     int registration_id,
     const std::string& value,
     ServiceWorkerStatusCode status) {
   if (status != SERVICE_WORKER_OK) {
     Send(new ServiceWorkerMsg_SetNavigationPreloadHeaderError(
         thread_id, request_id, WebServiceWorkerError::kErrorTypeUnknown,
         std::string(kSetNavigationPreloadHeaderErrorPrefix) +
             std::string(kDatabaseErrorMessage)));
     return;
   }
+  if (!GetContext())
+    return;
   ServiceWorkerRegistration* registration =
       GetContext()->GetLiveRegistration(registration_id);
   if (registration)
     registration->SetNavigationPreloadHeader(value);
   Send(new ServiceWorkerMsg_DidSetNavigationPreloadHeader(thread_id,
                                                           request_id));
 }
 
 void ServiceWorkerDispatcherHost::OnTerminateWorker(int handle_id) {
   ServiceWorkerHandle* handle = handles_.Lookup(handle_id);
   if (!handle) {
     bad_message::ReceivedBadMessage(this,
                                     bad_message::SWDH_TERMINATE_BAD_HANDLE);
     return;
   }
   handle->version()->StopWorker(
       base::Bind(&ServiceWorkerUtils::NoOpStatusCallback));
 }
 
 }  // namespace content