Provide skeleton functionality for AppCache handling in the network service.

content/browser/appcache/appcache_network_service_handler.h

+// Copyright (c) 2017 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_NETWORK_SERVICE_HANDLER_
+#define CONTENT_BROWSER_APPCACHE_APPCACHE_NETWORK_SERVICE_HANDLER_
+
+#include <memory>
+
+#include "base/macros.h"
+#include "content/browser/appcache/appcache_service_impl.h"
+#include "content/browser/appcache/appcache_storage.h"
+#include "content/common/content_export.h"
+#include "content/common/url_loader_factory.mojom.h"
+#include "content/public/common/resource_type.h"
+
+namespace content {
+class AppCacheEntry;
+class AppCacheHost;
+class AppCacheNavigationHandleCore;
+class AppCacheStorage;
+class ResourceContext;
+struct ResourceRequest;
+
+// This class is instantiated during navigation, to check if the URL being
+// navigated to can be served out of the AppCache.
+// The AppCacheRequestHandler class provides this functionality as well.
+// However it is tightly coupled with the underlying job and the lifetime
+// of that class gets a touch complicated. The AppCacheRequestHandler is
+// generally associated with a request and it dies when the request goes away.
+// For this case, we are just checking if the URL can be served out of the
+// cache. If yes, then the plan is to create a URLLoaderFactory which can serve
+// URL requests from the cache.
+// TODO(ananta)
+// Look into whether we can get rid of this class when the overall picture of
+// how AppCache interacts with the network service gets clearer.
+class CONTENT_EXPORT AppCacheNetworkServiceHandler
+    : public AppCacheStorage::Delegate {
+ public:
+  AppCacheNetworkServiceHandler(
+      std::unique_ptr<ResourceRequest> resource_request,
+      AppCacheNavigationHandleCore* navigation_handle_core,
+      base::Callback<void(mojom::URLLoaderFactoryPtrInfo,
+                          std::unique_ptr<ResourceRequest>)> callback);
+
+  ~AppCacheNetworkServiceHandler() override;
+
+  // Called to start the process of looking up the URL in the AppCache
+  // database,
+  void Start();
+
+  // AppCacheStorage::Delegate methods
+  // The AppCacheNetworkServiceHandler instance is deleted on return from this
+  // function.
+  void OnMainResponseFound(const GURL& url,
+                           const AppCacheEntry& entry,
+                           const GURL& fallback_url,
+                           const AppCacheEntry& fallback_entry,
+                           int64_t cache_id,
+                           int64_t group_id,
+                           const GURL& mainfest_url) override;
+
+ private:
+  std::unique_ptr<ResourceRequest> resource_request_;
+
+  // Callback to invoke when we make a determination on whether the request is
+  // to be served from the cache or network.
+  base::Callback<void(mojom::URLLoaderFactoryPtrInfo,
+                      std::unique_ptr<ResourceRequest>)> callback_;
+
+  AppCacheStorage* storage_;
+
+  // The precreated host pointer from the AppCacheNavigationHandleCore class.
+  // The ownership of this pointer stays with the AppCacheNavigationHandleCore
+  // class.
+  AppCacheHost* host_;
+
+  DISALLOW_COPY_AND_ASSIGN(AppCacheNetworkServiceHandler);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_APPCACHE_APPCACHE_NETWORK_SERVICE_HANDLER_