Disk Cache: Make Stats independent of the backend implementation.

net/disk_cache/backend_impl.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.
 
 // See net/disk_cache/disk_cache.h for the public interface of the cache.
 
 #ifndef NET_DISK_CACHE_BACKEND_IMPL_H_
 #define NET_DISK_CACHE_BACKEND_IMPL_H_
 
 #include "base/files/file_path.h"
@@ skipping 262 matching lines @@
   virtual void OnExternalCacheHit(const std::string& key) OVERRIDE;
 
  private:
   typedef base::hash_map<CacheAddr, EntryImpl*> EntriesMap;
 
   // Creates a new backing file for the cache index.
   bool CreateBackingStore(disk_cache::File* file);
   bool InitBackingStore(bool* file_created);
   void AdjustMaxCacheSize(int table_len);
 
+  bool InitStats();
+  void StoreStats();
+
   // Deletes the cache and starts again.
   void RestartCache(bool failure);
   void PrepareForRestart();
 
   // Creates a new entry object. Returns zero on success, or a disk_cache error
   // on failure.
   int NewEntry(Addr address, EntryImpl** entry);
 
   // Returns a given entry from the cache. The entry to match is determined by
   // key and hash, and the returned entry may be the matched one or it's parent
@@ skipping 93 matching lines @@
 
   DISALLOW_COPY_AND_ASSIGN(BackendImpl);
 };
 
 // Returns the preferred max cache size given the available disk space.
 NET_EXPORT_PRIVATE int PreferedCacheSize(int64 available);
 
 }  // namespace disk_cache
 
 #endif  // NET_DISK_CACHE_BACKEND_IMPL_H_