Check the existence of provider_host in ServiceWorkerURLTrackingRequestHandler::MaybeCreateJob()

content/browser/service_worker/service_worker_provider_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_provider_host.h"
 
 #include <utility>
 
 #include "base/guid.h"
 #include "base/memory/ptr_util.h"
@@ skipping 42 matching lines @@
                                     provider_host,
                                     blob_storage_context,
                                     resource_type) {}
   ~ServiceWorkerURLTrackingRequestHandler() override {}
 
   // Called via custom URLRequestJobFactory.
   net::URLRequestJob* MaybeCreateJob(
       net::URLRequest* request,
       net::NetworkDelegate* network_delegate,
       ResourceContext* resource_context) override {
+    // |provider_host_| may have been deleted when the request is resumed.
+    if (!provider_host_)
+      return nullptr;
     const GURL stripped_url = net::SimplifyUrlForRequest(request->url());
     provider_host_->SetDocumentUrl(stripped_url);
     provider_host_->SetTopmostFrameUrl(request->first_party_for_cookies());
     return nullptr;
   }
 
  private:
   DISALLOW_COPY_AND_ASSIGN(ServiceWorkerURLTrackingRequestHandler);
 };
 
@@ skipping 678 matching lines @@
           render_thread_id_, provider_id(),
           GetOrCreateServiceWorkerHandle(
               associated_registration_->active_version()),
           false /* shouldNotifyControllerChange */,
           associated_registration_->active_version()->used_features()));
     }
   }
 }
 
 }  // namespace content