Fix a ServiceWorker crasher

content/browser/service_worker/service_worker_controllee_request_handler.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/browser/service_worker/service_worker_controllee_request_handler.h"
 
 #include "base/debug/trace_event.h"
 #include "content/browser/service_worker/service_worker_context_core.h"
 #include "content/browser/service_worker/service_worker_metrics.h"
 #include "content/browser/service_worker/service_worker_provider_host.h"
@@ skipping 92 matching lines @@
     return;
   }
   job_->GetExtraResponseInfo(was_fetched_via_service_worker,
                              original_url_via_service_worker);
 }
 
 void ServiceWorkerControlleeRequestHandler::PrepareForMainResource(
     const GURL& url) {
   DCHECK(job_.get());
   DCHECK(context_);
+  DCHECK(provider_host_);
   TRACE_EVENT_ASYNC_BEGIN1(
       "ServiceWorker",
       "ServiceWorkerControlleeRequestHandler::PrepareForMainResource",
       job_.get(),
       "URL", url.spec());
   // The corresponding provider_host may already have associated a registration
   // in redirect case, unassociate it now.
   provider_host_->DisassociateRegistration();
 
   // Also prevent a registrater job for establishing an association to a new
   // registration while we're finding an existing registration.
   provider_host_->SetAllowAssociation(false);
 
   GURL stripped_url = net::SimplifyUrlForRequest(url);
   provider_host_->SetDocumentUrl(stripped_url);
   context_->storage()->FindRegistrationForDocument(
       stripped_url,
       base::Bind(&self::DidLookupRegistrationForMainResource,
                  weak_factory_.GetWeakPtr()));
 }
 
 void
 ServiceWorkerControlleeRequestHandler::DidLookupRegistrationForMainResource(
     ServiceWorkerStatusCode status,
     const scoped_refptr<ServiceWorkerRegistration>& registration) {
   DCHECK(job_.get());
-  provider_host_->SetAllowAssociation(true);
-  if (status != SERVICE_WORKER_OK) {
+  if (provider_host_)
+    provider_host_->SetAllowAssociation(true);
+  if (status != SERVICE_WORKER_OK || !provider_host_) {
     job_->FallbackToNetwork();
     TRACE_EVENT_ASYNC_END1(
         "ServiceWorker",
         "ServiceWorkerControlleeRequestHandler::PrepareForMainResource",
         job_.get(),
         "Status", status);
     return;
   }
   DCHECK(registration.get());
 
@@ skipping 47 matching lines @@
       "ServiceWorkerControlleeRequestHandler::PrepareForMainResource",
       job_.get(),
       "Status", status,
       "Info",
       "Forwarded to the ServiceWorker");
 }
 
 void ServiceWorkerControlleeRequestHandler::OnVersionStatusChanged(
     ServiceWorkerRegistration* registration,
     ServiceWorkerVersion* version) {
-  provider_host_->SetAllowAssociation(true);
+  if (provider_host_)
+    provider_host_->SetAllowAssociation(true);
   if (version != registration->active_version() ||
-      version->status() != ServiceWorkerVersion::ACTIVATED) {
+      version->status() != ServiceWorkerVersion::ACTIVATED ||
+      !provider_host_) {
     job_->FallbackToNetwork();
     return;
   }
 
   ServiceWorkerMetrics::CountControlledPageLoad();
 
   provider_host_->AssociateRegistration(registration);
   job_->ForwardToServiceWorker();
 }
 
 void ServiceWorkerControlleeRequestHandler::PrepareForSubResource() {
   DCHECK(job_.get());
   DCHECK(context_);
   DCHECK(provider_host_->active_version());
   job_->ForwardToServiceWorker();
 }
 
 }  // namespace content