Most Visited: remove over-eager optimization that causes a lot of blank thumbnails

chrome/browser/history/top_sites_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.
 
 #ifndef CHROME_BROWSER_HISTORY_TOP_SITES_CACHE_H_
 #define CHROME_BROWSER_HISTORY_TOP_SITES_CACHE_H_
 #pragma once
 
 #include <algorithm>
 #include <map>
@@ skipping 13 matching lines @@
   ~TopSitesCache();
 
   // The top sites.
   void SetTopSites(const MostVisitedURLList& top_sites);
   const MostVisitedURLList& top_sites() const { return top_sites_; }
 
   // The thumbnails.
   void SetThumbnails(const URLToImagesMap& images);
   const URLToImagesMap& images() const { return images_; }
 
-  // Set a thumbnail.
-  void SetPageThumbnail(const GURL& url,
-                        RefCountedBytes* thumbnail,
-                        const ThumbnailScore& score);
-
   // Returns the thumbnail as an Image for the specified url. This adds an entry
   // for |url| if one has not yet been added.
   Images* GetImage(const GURL& url);
 
   // Fetches the thumbnail for the specified url. Returns true if there is a
   // thumbnail for the specified url. It is possible for a URL to be in TopSites
   // but not have an thumbnail.
   bool GetPageThumbnail(const GURL& url,
                         scoped_refptr<RefCountedBytes>* bytes);
 
   // Fetches the thumbnail score for the specified url. Returns true if
   // there is a thumbnail score for the specified url.
   bool GetPageThumbnailScore(const GURL& url, ThumbnailScore* score);
 
   // Returns the canonical URL for |url|.
   GURL GetCanonicalURL(const GURL& url);
 
   // Returns true if |url| is known.
   bool IsKnownURL(const GURL& url);
 
   // Returns the index into |top_sites_| for |url|.
   size_t GetURLIndex(const GURL& url);
 
-  // Removes any thumbnails that are no longer referenced by the top sites.
-  void RemoveUnreferencedThumbnails();
-
  private:
   // The entries in CanonicalURLs, see CanonicalURLs for details. The second
   // argument gives the index of the URL into MostVisitedURLs redirects.
   typedef std::pair<MostVisitedURL*, size_t> CanonicalURLEntry;
 
   // Comparator used for CanonicalURLs.
   class CanonicalURLComparator {
    public:
     bool operator()(const CanonicalURLEntry& e1,
                     const CanonicalURLEntry& e2) const {
@@ skipping 29 matching lines @@
   // Generated from the redirects to and from the most visited pages. See
   // description above typedef for details.
   CanonicalURLs canonical_urls_;
 
   DISALLOW_COPY_AND_ASSIGN(TopSitesCache);
 };
 
 }  // namespace history
 
 #endif  // CHROME_BROWSER_HISTORY_TOP_SITES_CACHE_H_