Adding last_forced column to thumbnails database.

chrome/browser/history/top_sites_database.h

 // Copyright (c) 2012 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_DATABASE_H_
 #define CHROME_BROWSER_HISTORY_TOP_SITES_DATABASE_H_
 
 #include <map>
 #include <string>
 
@@ skipping 42 matching lines @@
 
   // Get a thumbnail for a given page. Returns true iff we have the thumbnail.
   bool GetPageThumbnail(const GURL& url, Images* thumbnail);
 
   // Remove the record for this URL. Returns true iff removed successfully.
   bool RemoveURL(const MostVisitedURL& url);
 
  private:
   FRIEND_TEST_ALL_PREFIXES(TopSitesDatabaseTest, Version1);
   FRIEND_TEST_ALL_PREFIXES(TopSitesDatabaseTest, Version2);
+  FRIEND_TEST_ALL_PREFIXES(TopSitesDatabaseTest, Version3);
+  FRIEND_TEST_ALL_PREFIXES(TopSitesDatabaseTest, AddRemoveEditThumbnails);
+
+  // Rank of all URLs that are forced and therefore cannot be automatically
+  // evicted.
+  static const int kRankOfForcedURL = -1;
+
+  // Rank used to indicate that a URL is not stored in the database.
+  static const int kRankOfNonExistingURL = -2;
 
   // Creates the thumbnail table, returning true if the table already exists
   // or was successfully created.
   bool InitThumbnailTable();
 
   // Upgrades the thumbnail table to version 2, returning true if the
   // upgrade was successful.
   bool UpgradeToVersion2();
 
+  // Upgrades the thumbnail table to version 3, returning true if the
+  // upgrade was successful.
+  bool UpgradeToVersion3();
+
   // Adds a new URL to the database.
   void AddPageThumbnail(const MostVisitedURL& url,
                         int new_rank,
                         const Images& thumbnail);
 
   // Sets the page rank. Should be called within an open transaction.
   void UpdatePageRankNoTransaction(const MostVisitedURL& url, int new_rank);
 
   // Updates thumbnail of a URL that's already in the database.
   // Returns true if the database query succeeds.
   bool UpdatePageThumbnail(const MostVisitedURL& url,
                            const Images& thumbnail);
 
-  // Returns the URL's current rank or -1 if it is not present.
+  // Returns |url|'s current rank or kRankOfNonExistingURL if not present.
   int GetURLRank(const MostVisitedURL& url);
 
-  // Returns the number of URLs (rows) in the database.
-  int GetRowCount();
-
   sql::Connection* CreateDB(const base::FilePath& db_name);
 
   // Encodes redirects into a string.
   static std::string GetRedirects(const MostVisitedURL& url);
 
   // Decodes redirects from a string and sets them for the url.
   static void SetRedirects(const std::string& redirects, MostVisitedURL* url);
 
   scoped_ptr<sql::Connection> db_;
   sql::MetaTable meta_table_;
 
   DISALLOW_COPY_AND_ASSIGN(TopSitesDatabase);
 };
 
 }  // namespace history
 
 #endif  // CHROME_BROWSER_HISTORY_TOP_SITES_DATABASE_H_