Revert 152946 - Replace HistoryQuickProvider protobuf-based caching with an SQLite-based database.

chrome/browser/history/scored_history_match.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_SCORED_HISTORY_MATCH_H_
 #define CHROME_BROWSER_HISTORY_SCORED_HISTORY_MATCH_H_
 
 #include <map>
 #include <set>
 #include <vector>
 
 #include "base/string16.h"
 #include "chrome/browser/history/history_types.h"
 #include "chrome/browser/autocomplete/history_provider_util.h"
 #include "chrome/browser/history/in_memory_url_index_types.h"
 
 namespace history {
 
 // An HistoryMatch that has a score as well as metrics defining where in the
 // history item's URL and/or page title matches have occurred.
 struct ScoredHistoryMatch : public history::HistoryMatch {
   ScoredHistoryMatch();  // Required by STL.
 
   // Creates a new match with a raw score calculated for the history item given
-  // in |row|. First determines if the row qualifies by seeing if all of the
-  // terms in |terms_vector| occur in |row|. If so, calculates a raw score.
-  // This raw score allows the results to be ordered and can be used to
-  // influence the final score calculated by the client of this index.
-  // If the row does not qualify the raw score will be 0.
+  // in |row| by first determining if all of the terms in |terms_vector| occur
+  // in |row| and, if so, calculating a raw score based on 1) starting position
+  // of each term in the user input, 2) completeness of each term's match,
+  // 3) ordering of the occurrence of each term (i.e. they appear in order),
+  // 4) last visit time (compared to |now|), and 5) number of visits.
+  // This raw score allows the results to be ordered and can be used
+  // to influence the final score calculated by the client of this
+  // index.
   ScoredHistoryMatch(const URLRow& row,
                      const string16& lower_string,
                      const String16Vector& terms_vector,
                      const RowWordStarts& word_starts,
                      const base::Time now);
   ~ScoredHistoryMatch();
 
   // Calculates a component score based on position, ordering and total
   // substring match size using metrics recorded in |matches|. |max_length|
   // is the length of the string against which the terms are being searched.
@@ skipping 91 matching lines @@
 
   // Whether to use new-score or old-scoring.  Set in the constructor
   // by examining command line flags.
   static bool use_new_scoring;
 };
 typedef std::vector<ScoredHistoryMatch> ScoredHistoryMatches;
 
 }  // namespace history
 
 #endif  // CHROME_BROWSER_HISTORY_SCORED_HISTORY_MATCH_H_