Cache failover to LOAD_PREFERRING_CACHE if network response suggests offline.

net/http/http_response_info.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 NET_HTTP_HTTP_RESPONSE_INFO_H_
 #define NET_HTTP_HTTP_RESPONSE_INFO_H_
 
 #include <string>
 
 #include "base/time.h"
@@ skipping 41 matching lines @@
 
   // The following is only defined if the request_time member is set.
   // If this response was resurrected from cache, then this bool is set, and
   // request_time may corresponds to a time "far" in the past.  Note that
   // stale content (perhaps un-cacheable) may be fetched from cache subject to
   // the load flags specified on the request info.  For example, this is done
   // when a user presses the back button to re-render pages, or at startup,
   // when reloading previously visited pages (without going over the network).
   bool was_cached;
 
+  // True if the request was fetched from cache rather than the network
+  // because of a LOAD_FROM_CACHE_IF_OFFLINE flag when the system
+  // was unable to contact the server.
+  bool server_data_unavailable;
+
   // True if the request was fetched over a SPDY channel.
   bool was_fetched_via_spdy;
 
   // True if the npn was negotiated for this request.
   bool was_npn_negotiated;
 
   // True if the request was fetched via an explicit proxy.  The proxy could
   // be any type of proxy, HTTP or SOCKS.  Note, we do not know if a
   // transparent proxy may have been involved.
   bool was_fetched_via_proxy;
@@ skipping 40 matching lines @@
   // The "Vary" header data for this response.
   HttpVaryData vary_data;
 
   // Any metadata asociated with this resource's cached data.
   scoped_refptr<IOBufferWithSize> metadata;
 };
 
 }  // namespace net
 
 #endif  // NET_HTTP_HTTP_RESPONSE_INFO_H_