Implement offline mode behind a flag

net/http/http_response_info.h

Index: net/http/http_response_info.h
diff --git a/net/http/http_response_info.h b/net/http/http_response_info.h
index e0bb41a03bb7e41cdfdd22b44809b5f05a2a4564..de27825465f7be0092e1b06e115220751e626dbb 100644
--- a/net/http/http_response_info.h
+++ b/net/http/http_response_info.h
@@ -64,6 +64,10 @@ class NET_EXPORT HttpResponseInfo {
   // was unable to contact the server.
   bool server_data_unavailable;
 
+  // True if the request accessed the network in the process of retrieving
+  // data.
+  bool network_accessed;
+
   // True if the request was fetched over a SPDY channel.
   bool was_fetched_via_spdy;