Disk cache: Remove remaining uses of RankingsNode.pointer....

net/disk_cache/rankings.h

 // Copyright (c) 2006-2008 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.
 
 #ifndef NET_DISK_CACHE_RANKINGS_H_
 #define NET_DISK_CACHE_RANKINGS_H_
 
 #include <list>
@@ skipping 129 matching lines @@
 
  private:
   typedef std::pair<CacheAddr, CacheRankingsBlock*> IteratorPair;
   typedef std::list<IteratorPair> IteratorList;
 
   void ReadHeads();
   void ReadTails();
   void WriteHead(List list);
   void WriteTail(List list);
 
-  // Gets the rankings information for a given rankings node.
+  // Gets the rankings information for a given rankings node. We may end up
+  // sharing the actual memory with a loaded entry, but we are not taking a
+  // reference to that entry, so |rankings| must be short lived.
   bool GetRanking(CacheRankingsBlock* rankings);
 
+  // Makes |rankings| suitable to live a long life.
+  void ConvertToLongLived(CacheRankingsBlock* rankings);
+
   // Finishes a list modification after a crash.
   void CompleteTransaction();
   void FinishInsert(CacheRankingsBlock* rankings);
   void RevertRemove(CacheRankingsBlock* rankings);
 
   // Returns false if this entry will not be recognized as dirty (called during
   // selfcheck).
   bool CheckEntry(CacheRankingsBlock* rankings);
 
   // Returns false if node is not properly linked.
@@ skipping 28 matching lines @@
   BackendImpl* backend_;
   LruData* control_data_;  // Data related to the LRU lists.
   IteratorList iterators_;
 
   DISALLOW_COPY_AND_ASSIGN(Rankings);
 };
 
 }  // namespace disk_cache
 
 #endif  // NET_DISK_CACHE_RANKINGS_H_