Cache Backend Proxy to intercept all cache events from the IO thread.

net/disk_cache/simple/simple_disk_format.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_DISK_FORMAT_H_
 #define NET_DISK_CACHE_SIMPLE_SIMPLE_DISK_FORMAT_H_
 
 #include <string>
 
 #include "base/basictypes.h"
 #include "base/port.h"
 
 namespace base {
 class Time;
 }
 
 namespace disk_cache {
 
 const uint64 kSimpleInitialMagicNumber = GG_UINT64_C(0xfcfb6d1ba7725c30);
 const uint64 kSimpleIndexInitialMagicNumber = GG_UINT64_C(0x656e74657220796f);
 
 // A file in the Simple cache consists of a SimpleFileHeader followed
 // by data.
 
 const uint32 kSimpleVersion = 1;
 
 static const int kSimpleEntryFileCount = 3;
 
 struct SimpleFileHeader {
+  SimpleFileHeader();
   uint64 initial_magic_number;
   uint32 version;
   uint32 key_length;
   uint32 key_hash;
 };
 
 // kHashKeySize must conform to the pattern in the GetHashForKey function.
 const int kEntryHashKeySize = 10;
 std::string GetEntryHashForKey(const std::string& key);
 
@@ skipping 63 matching lines @@
   struct Footer {
     Footer();
     uint32 crc;
   };
 
 }  // namespace SimpleIndexFile
 
 }  // namespace disk_cache
 
 #endif  // NET_DISK_CACHE_SIMPLE_SIMPLE_DISK_FORMAT_H_