Add a size estimation mechanism to StoragePartitionHttpCacheDataRemover.

net/disk_cache/blockfile/backend_impl_v3.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_BLOCKFILE_BACKEND_IMPL_V3_H_
 #define NET_DISK_CACHE_BLOCKFILE_BACKEND_IMPL_V3_H_
 
 #include "base/containers/hash_tables.h"
@@ skipping 170 matching lines @@
                   Entry** entry,
                   const CompletionCallback& callback) override;
   int DoomEntry(const std::string& key,
                 const CompletionCallback& callback) override;
   int DoomAllEntries(const CompletionCallback& callback) override;
   int DoomEntriesBetween(base::Time initial_time,
                          base::Time end_time,
                          const CompletionCallback& callback) override;
   int DoomEntriesSince(base::Time initial_time,
                        const CompletionCallback& callback) override;
+  int CalculateSizeOfAllEntries(const CompletionCallback& callback) override;
   scoped_ptr<Iterator> CreateIterator() override;
   void GetStats(StatsItems* stats) override;
   void OnExternalCacheHit(const std::string& key) override;
 
  private:
   friend class EvictionV3;
   typedef base::hash_map<CacheAddr, EntryImplV3*> EntriesMap;
   class IteratorImpl;
   class NotImplementedIterator;
   class Worker;
@@ skipping 73 matching lines @@
   scoped_ptr<base::RepeatingTimer> timer_;   // Usage timer.
   scoped_refptr<TraceObject> trace_object_;  // Initializes internal tracing.
   base::WeakPtrFactory<BackendImplV3> ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(BackendImplV3);
 };
 
 }  // namespace disk_cache
 
 #endif  // NET_DISK_CACHE_BLOCKFILE_BACKEND_IMPL_V3_H_