A crude cut at incorporating stream 1 footer read into stream 0 read.

net/disk_cache/simple/simple_synchronous_entry.h

 // Copyright (c) 2013 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_DISK_CACHE_SIMPLE_SIMPLE_SYNCHRONOUS_ENTRY_H_
 #define NET_DISK_CACHE_SIMPLE_SIMPLE_SYNCHRONOUS_ENTRY_H_
 
 #include <stdint.h>
 
 #include <algorithm>
@@ skipping 362 matching lines @@
   bool header_and_key_check_needed_[kSimpleEntryFileCount] = {
       false,
   };
 
   base::File files_[kSimpleEntryFileCount];
 
   // True if the corresponding stream is empty and therefore no on-disk file
   // was created to store it.
   bool empty_file_omitted_[kSimpleEntryFileCount];
 
+  uint32_t stream1_crc32_;
+  bool has_stream1_crc32_;
+  bool read_stream1_crc32_;
+
   typedef std::map<int64_t, SparseRange> SparseRangeOffsetMap;
   typedef SparseRangeOffsetMap::iterator SparseRangeIterator;
   SparseRangeOffsetMap sparse_ranges_;
   base::File sparse_file_;
   // Offset of the end of the sparse file (where the next sparse range will be
   // written).
   int64_t sparse_tail_offset_;
 
   // True if the entry was created, or false if it was opened. Used to log
   // SimpleCache.*.EntryCreatedWithStream2Omitted only for created entries.
   bool files_created_;
 };
 
 }  // namespace disk_cache
 
 #endif  // NET_DISK_CACHE_SIMPLE_SIMPLE_SYNCHRONOUS_ENTRY_H_