Cache failover to LOAD_PREFERRING_CACHE if network response suggests offline.

net/http/http_cache_transaction.h

 // Copyright (c) 2012 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.
 
 // This file declares HttpCache::Transaction, a private class of HttpCache so
 // it should only be included by http_cache.cc
 
 #ifndef NET_HTTP_HTTP_CACHE_TRANSACTION_H_
 #define NET_HTTP_HTTP_CACHE_TRANSACTION_H_
 
@@ skipping 295 matching lines @@
   // partial entry.
   bool ValidatePartialResponse();
 
   // Handles a response validation error by bypassing the cache.
   void IgnoreRangeRequest();
 
   // Changes the response code of a range request to be 416 (Requested range not
   // satisfiable).
   void FailRangeRequest();
 
+  // Setups the transaction for reading from the cache entry.
+  int SetupEntryForRead();
+
   // Reads data from the network.
   int ReadFromNetwork(IOBuffer* data, int data_len);
 
   // Reads data from the cache entry.
   int ReadFromEntry(IOBuffer* data, int data_len);
 
   // Called to write data to the cache entry.  If the write fails, then the
   // cache entry is destroyed.  Future calls to this function will just do
   // nothing without side-effect.  Returns a network error code.
   int WriteToEntry(int index, int offset, IOBuffer* data, int data_len,
@@ skipping 84 matching lines @@
   State target_state_;
   bool reading_;  // We are already reading.
   bool invalid_range_;  // We may bypass the cache for this request.
   bool truncated_;  // We don't have all the response data.
   bool is_sparse_;  // The data is stored in sparse byte ranges.
   bool range_requested_;  // The user requested a byte range.
   bool handling_206_;  // We must deal with this 206 response.
   bool cache_pending_;  // We are waiting for the HttpCache.
   bool done_reading_;
   bool vary_mismatch_;  // The request doesn't match the stored vary data.
+  bool couldnt_conditionalize_request_;
   scoped_refptr<IOBuffer> read_buf_;
   int io_buf_len_;
   int read_offset_;
   int effective_load_flags_;
   int write_len_;
   scoped_ptr<PartialData> partial_;  // We are dealing with range requests.
   UploadProgress final_upload_progress_;
   base::WeakPtrFactory<Transaction> weak_factory_;
   CompletionCallback io_callback_;
 
@@ skipping 22 matching lines @@
 
 #if !defined(NDEBUG)
   // Record of all states this transaction has moved through.
   std::vector<int> state_path_;
 #endif
 };
 
 }  // namespace net
 
 #endif  // NET_HTTP_HTTP_CACHE_TRANSACTION_H_