Add support for subresource request fallback in AppCache for the network service..

content/browser/appcache/appcache_request_handler.h

 // Copyright (c) 2011 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_APPCACHE_APPCACHE_REQUEST_HANDLER_H_
 #define CONTENT_BROWSER_APPCACHE_APPCACHE_REQUEST_HANDLER_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 106 matching lines @@
 
   // Called just before the request is restarted. Grabs the reason for
   // restarting, so can correctly continue to handle the request.
   void OnPrepareToRestart();
 
   // Helper method to create an AppCacheJob and populate job_.
   // Caller takes ownership of returned value.
   std::unique_ptr<AppCacheJob> CreateJob(
       net::NetworkDelegate* network_delegate);
 
+  // Helper method to create an AppCacheJob for fallback responses.
+  std::unique_ptr<AppCacheJob> MaybeCreateJobForFallback(
+      net::NetworkDelegate* network_delegate);
+
   // Helper to retrieve a pointer to the storage object.
   AppCacheStorage* storage() const;
 
   bool is_main_resource() const {
     return IsMainResourceType(resource_type_);
   }
 
   // Main-resource loading -------------------------------------
   // Frame and SharedWorker main resources are handled here.
 
@@ skipping 106 matching lines @@
   // The AppCache host instance. We pass this to the
   // AppCacheSubresourceURLFactory instance on creation.
   base::WeakPtr<AppCacheHost> appcache_host_;
 
   DISALLOW_COPY_AND_ASSIGN(AppCacheRequestHandler);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_APPCACHE_APPCACHE_REQUEST_HANDLER_H_