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 273 matching lines @@
   // is a pending operation that has not been cancelled, this method will return
   // OK although another IO operation cannot be issued at this time; in this
   // case the caller should just wait for the regular callback to be invoked
   // instead of using this method to provide another callback.
   //
   // Note that CancelSparseIO may have been called on another instance of this
   // object that refers to the same physical disk entry.
   // Note: This method is deprecated.
   virtual int ReadyForSparseIO(CompletionCallback* completion_callback) = 0;
 
+  // Improves the rank of this entry in the LRU cache as if it had been used
+  // directly. This allows feedback from the renderer's memory cache to improve

[rvargas (doing something else), 2011/07/27 23:26:17]

net is not aware of what a renderer is. I think that the name of this method is
a bit too specific... it implies that the caller knows what a "rank" is, and the
comments talks about LRU...

Maybe something closer to OnExternalCacheHit(), OnEntryReused(),
EntryReused()...

Also, this should be a member of the backend and not the entry: if the user has
an open entry there is little to do, and if it has to open the entry that should
do the trick by itself. (note that making this change implies that my previous
comment about the location of the test is no longer valid)

+  // the selection of resources in the disk cache.
+  virtual void UpdateRankForExternalCacheHit() = 0;
+
  protected:
   virtual ~Entry() {}
 };
 
 }  // namespace disk_cache
 
 #endif  // NET_DISK_CACHE_DISK_CACHE_H_