Inform disk cache of WebKit memory cache hits.

net/disk_cache/disk_cache.h

 // Copyright (c) 2011 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.
 
 // Defines the public interface of the disk cache. For more details see
 // http://dev.chromium.org/developers/design-documents/network-stack/disk-cache
 
 #ifndef NET_DISK_CACHE_DISK_CACHE_H_
 #define NET_DISK_CACHE_DISK_CACHE_H_
 #pragma once
@@ skipping 119 matching lines @@
 
   // Releases iter without returning the next entry. Whenever OpenNextEntry()
   // returns true, but the caller is not interested in continuing the
   // enumeration by calling OpenNextEntry() again, the enumeration must be
   // ended by calling this method with iter returned by OpenNextEntry().
   virtual void EndEnumeration(void** iter) = 0;
 
   // Return a list of cache statistics.
   virtual void GetStats(
       std::vector<std::pair<std::string, std::string> >* stats) = 0;
+
+  // Improves the rank of the specified resource in the LRU cache as if it had
+  // been used directly. This allows feedback from the renderer's memory cache

[rvargas (doing something else), 2011/07/28 22:27:01]

There should not be a reference to the renderer's memory cache here.

Also, stating that there is an LRU cache is not a good idea, because in fact the
default cache is not LRU... and what does it means to improve the rank of a
resource? That is an implementation detail.

We should just limit the documentation to the invariant part: That this method
should be called whenever there is an  external cache that is serving this entry
and we expect that entry to be stored by this cache. What we do with that
information is implementation specific.

+  // to improve the selection of resources in the disk cache.
+  virtual void OnExternalCacheHit(const std::string& key) = 0;
 };
 
 // This interface represents an entry in the disk cache.
 class NET_TEST Entry {
  public:
   // Marks this cache entry for deletion.
   virtual void Doom() = 0;
 
   // Releases this entry. Calling this method does not cancel pending IO
   // operations on this entry. Even after the last reference to this object has
@@ skipping 141 matching lines @@
   // Note: This method is deprecated.
   virtual int ReadyForSparseIO(CompletionCallback* completion_callback) = 0;
 
  protected:
   virtual ~Entry() {}
 };
 
 }  // namespace disk_cache
 
 #endif  // NET_DISK_CACHE_DISK_CACHE_H_