predictors: Version the resource_prefetch_predictor database.

chrome/browser/predictors/resource_prefetch_predictor_tables.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 CHROME_BROWSER_PREDICTORS_RESOURCE_PREFETCH_PREDICTOR_TABLES_H_
 #define CHROME_BROWSER_PREDICTORS_RESOURCE_PREFETCH_PREDICTOR_TABLES_H_
 
 #include <stddef.h>
 
 #include <map>
@@ skipping 134 matching lines @@
                         const std::vector<std::string>& keys);
 
   // Returns true if the strings in the |data| are less than |kMaxStringLength|
   // in length.
   bool StringsAreSmallerThanDBLimit(const PrefetchData& data) const;
 
   // PredictorTableBase methods.
   void CreateTableIfNonExistent() override;
   void LogDatabaseStats() override;
 
-  bool DropTablesIfOutdated(sql::Connection* db);
+  static bool DropTablesIfOutdated(sql::Connection* db);
 
   // Helpers to return Statements for cached Statements. The caller must take
   // ownership of the return Statements.
   sql::Statement* GetUrlResourceDeleteStatement();
   sql::Statement* GetUrlResourceUpdateStatement();
   sql::Statement* GetUrlMetadataDeleteStatement();
   sql::Statement* GetUrlMetadataUpdateStatement();
 
   sql::Statement* GetHostResourceDeleteStatement();
   sql::Statement* GetHostResourceUpdateStatement();
   sql::Statement* GetHostMetadataDeleteStatement();
   sql::Statement* GetHostMetadataUpdateStatement();
 
   DISALLOW_COPY_AND_ASSIGN(ResourcePrefetchPredictorTables);
 };
 
 }  // namespace predictors
 
 #endif  // CHROME_BROWSER_PREDICTORS_RESOURCE_PREFETCH_PREDICTOR_TABLES_H_