Add an abstraction for a job in the AppCacheRequestHandler class.

content/browser/appcache/appcache_request.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_REQUEST_H_
 #define CONTENT_BROWSER_APPCACHE_APPCACHE_REQUEST_H_
 
 #include "base/logging.h"
 #include "base/strings/string16.h"
 #include "base/threading/non_thread_safe.h"
@@ skipping 43 matching lines @@
   // wasn't found,
   virtual std::string GetResponseHeaderByName(
       const std::string& name) const = 0;
 
   // Returns true if the scheme and method are supported for AppCache.
   static bool IsSchemeAndMethodSupportedForAppCache(
       const AppCacheRequest* request);
 
  protected:
   friend class AppCacheRequestHandler;
+  // Enables the AppCacheJob to call GetURLRequest() and GetResourceRequest().
+  friend class AppCacheJob;
 
   AppCacheRequest() {}
 
   // Getters for the request types we currently support.
   virtual net::URLRequest* GetURLRequest();
 
   // Returns the underlying ResourceRequest. Please note that only one of
   // GetURLRequest() and GetResourceRequest() should return valid results.
   virtual ResourceRequest* GetResourceRequest();
 
   DISALLOW_COPY_AND_ASSIGN(AppCacheRequest);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_APPCACHE_APPCACHE_REQUEST_H_