ServiceWorker: Confirm the liveness of the associated context before handling message

content/browser/service_worker/service_worker_register_job.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_register_job.h"
 
 #include <vector>
 
 #include "base/message_loop/message_loop.h"
 #include "content/browser/service_worker/service_worker_context_core.h"
@@ skipping 394 matching lines @@
     base::WeakPtr<ServiceWorkerContextCore> context,
     ServiceWorkerVersion* version) {
   DCHECK(context);
   DCHECK(version);
 
   for (scoped_ptr<ServiceWorkerContextCore::ProviderHostIterator> it =
            context->GetProviderHostIterator();
        !it->IsAtEnd();
        it->Advance()) {
     ServiceWorkerProviderHost* host = it->GetProviderHost();
+    if (!host->IsContextAlive())
+      continue;
     if (ServiceWorkerUtils::ScopeMatches(version->scope(),
                                          host->document_url())) {
       // The spec's _Update algorithm says, "upgrades active version to a new
       // version for the same URL scope.", so skip if the scope (registration)
       // of |version| is different from that of the current active/waiting
       // version.
       if (!host->ValidateVersionForAssociation(version))
         continue;
 
       // TODO(nhiroki): Keep |host->waiting_version()| to be replaced and set
       // status of them to 'redandunt' after breaking the loop.
 
       host->SetWaitingVersion(version);
       // TODO(nhiroki): Set |host|'s installing version to null.
     }
   }
 }
 
 // static
 void ServiceWorkerRegisterJob::DisassociateWaitingVersionFromDocuments(
     base::WeakPtr<ServiceWorkerContextCore> context,
     int64 version_id) {
   DCHECK(context);
   for (scoped_ptr<ServiceWorkerContextCore::ProviderHostIterator> it =
            context->GetProviderHostIterator();
        !it->IsAtEnd();
        it->Advance()) {
     ServiceWorkerProviderHost* host = it->GetProviderHost();
+    if (!host->IsContextAlive())
+      continue;
     if (host->waiting_version() &&
         host->waiting_version()->version_id() == version_id) {
       host->SetWaitingVersion(NULL);
     }
   }
 }
 
 }  // namespace content