V4LDM: Add check for HashPrefix match and some tests

components/safe_browsing_db/v4_database.h

 // Copyright 2016 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_SAFE_BROWSING_DB_V4_DATABASE_H_
 #define COMPONENTS_SAFE_BROWSING_DB_V4_DATABASE_H_
 
 #include "base/callback.h"
 #include "base/files/file_path.h"
 #include "base/memory/ref_counted.h"
@@ skipping 63 matching lines @@
   // and calls the db_updated_callback when done.
   void ApplyUpdate(std::unique_ptr<ParsedServerResponse> parsed_server_response,
                    DatabaseUpdatedCallback db_updated_callback);
 
   // Returns the current state of each of the stores being managed.
   std::unique_ptr<StoreStateMap> GetStoreStateMap();
 
   // Searches for a hash prefix matching the |full_hash| in stores in the
   // database, filtered by |stores_to_look|, and returns the identifier of the
   // store along with the matching hash prefix in |matched_hash_prefix_map|.
-  void GetStoresMatchingFullHash(
+  virtual void GetStoresMatchingFullHash(
       const FullHash& full_hash,
       const base::hash_set<UpdateListIdentifier>& stores_to_look,
       MatchedHashPrefixMap* matched_hash_prefix_map);
 
   // Deletes the current database and creates a new one.
   virtual bool ResetDatabase();
 
  protected:
   V4Database(const scoped_refptr<base::SequencedTaskRunner>& db_task_runner,
              std::unique_ptr<StoreMap> store_map);
@@ skipping 45 matching lines @@
   // that needed updating and is ready for the next update. It should only be
   // accessed on the IO thread.
   int pending_store_updates_;
 
   DISALLOW_COPY_AND_ASSIGN(V4Database);
 };
 
 }  // namespace safe_browsing
 
 #endif  // COMPONENTS_SAFE_BROWSING_DB_V4_DATABASE_H_