Revert of Remove void** from disk_cache interface.

net/disk_cache/blockfile/backend_impl_v3.h

Index: net/disk_cache/blockfile/backend_impl_v3.h
diff --git a/net/disk_cache/blockfile/backend_impl_v3.h b/net/disk_cache/blockfile/backend_impl_v3.h
index ca649972f089459b362a0d1717a084202f350b94..b57bb8914e6a4a4600508588a14b90b526cdc064 100644
--- a/net/disk_cache/blockfile/backend_impl_v3.h
+++ b/net/disk_cache/blockfile/backend_impl_v3.h
@@ -186,15 +186,15 @@
                                  const CompletionCallback& callback) OVERRIDE;
   virtual int DoomEntriesSince(base::Time initial_time,
                                const CompletionCallback& callback) OVERRIDE;
-  virtual scoped_ptr<Iterator> CreateIterator() OVERRIDE;
+  virtual int OpenNextEntry(void** iter, Entry** next_entry,
+                            const CompletionCallback& callback) OVERRIDE;
+  virtual void EndEnumeration(void** iter) OVERRIDE;
   virtual void GetStats(StatsItems* stats) OVERRIDE;
   virtual void OnExternalCacheHit(const std::string& key) OVERRIDE;
 
  private:
   friend class EvictionV3;
   typedef base::hash_map<CacheAddr, EntryImplV3*> EntriesMap;
-  class IteratorImpl;
-  class NotImplementedIterator;
   class Worker;
 
   void AdjustMaxCacheSize();