base: Remove non-const refs from the MRUCache implementation.

components/dom_distiller/core/distilled_content_store.h

 // Copyright 2014 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.
 
 #ifndef COMPONENTS_DOM_DISTILLER_CORE_DOM_DISTILLER_CONTENT_STORE_H_
 #define COMPONENTS_DOM_DISTILLER_CORE_DOM_DISTILLER_CONTENT_STORE_H_
 
 #include <string>
 
 #include "base/bind.h"
@@ skipping 45 matching lines @@
   // Synchronously saves the content.
   void InjectContent(const ArticleEntry& entry,
                      const DistilledArticleProto& proto);
 
  private:
   // The CacheDeletor gets called when anything is removed from the ContentMap.
   class CacheDeletor {
    public:
     explicit CacheDeletor(InMemoryContentStore* store);
     ~CacheDeletor();
-    void operator()(const DistilledArticleProto& proto);
+    void operator()(DistilledArticleProto* proto);
 
    private:
     InMemoryContentStore* store_;
   };
 
   void AddUrlToIdMapping(const ArticleEntry& entry,
                          const DistilledArticleProto& proto);
 
   void EraseUrlToIdMapping(const DistilledArticleProto& proto);
 
   typedef base::MRUCacheBase<std::string,
                              DistilledArticleProto,
                              InMemoryContentStore::CacheDeletor> ContentMap;
   typedef base::hash_map<std::string, std::string> UrlMap;
 
   ContentMap cache_;
   UrlMap url_to_id_;
 };
 
 }  // dom_distiller
 
 #endif  // COMPONENTS_DOM_DISTILLER_CORE_DOM_DISTILLER_CONTENT_CACHE_H_