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

content/browser/service_worker/service_worker_provider_host.h

 // 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.
 
 #ifndef CONTENT_BROWSER_SERVICE_WORKER_SERVICE_WORKER_PROVIDER_HOST_H_
 #define CONTENT_BROWSER_SERVICE_WORKER_SERVICE_WORKER_PROVIDER_HOST_H_
 
 #include <set>
 #include <vector>
 
@@ skipping 75 matching lines @@
   // Returns a handler for a request, the handler may return NULL if
   // the request doesn't require special handling.
   scoped_ptr<ServiceWorkerRequestHandler> CreateRequestHandler(
       ResourceType::Type resource_type,
       base::WeakPtr<webkit_blob::BlobStorageContext> blob_storage_context);
 
   // Dispatches message event to the document.
   void PostMessage(const base::string16& message,
                    const std::vector<int>& sent_message_port_ids);
 
+  // Returns true if the context referred to by this host (i.e. |context_|) is
+  // still alive.
+  bool IsAlive();
+
  private:
   const int process_id_;
   const int provider_id_;
   GURL document_url_;
   scoped_refptr<ServiceWorkerVersion> active_version_;
   scoped_refptr<ServiceWorkerVersion> waiting_version_;
   scoped_refptr<ServiceWorkerVersion> running_hosted_version_;
   base::WeakPtr<ServiceWorkerContextCore> context_;
   ServiceWorkerDispatcherHost* dispatcher_host_;
 
   DISALLOW_COPY_AND_ASSIGN(ServiceWorkerProviderHost);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_SERVICE_WORKER_SERVICE_WORKER_PROVIDER_HOST_H_