Adding knobs on HQP provider.

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>
@@ skipping 11 matching lines @@
 
 // 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.
 class ScoredHistoryMatch : public history::HistoryMatch {
  public:
   // The maximum number of recent visits to examine in GetFrequency().
   // Public so url_index_private_data.cc knows how many visits it is
   // expected to deliver (at minimum) to this class.
   static const size_t kMaxVisitsToScore;
 
+  // ScoreMaxRelevance maps from an intermediate-score to the maximum
+  // final-relevance score given to a URL for this intermediate score.
+  // This is used to store the score ranges of HQP relevance buckets.
+  // Please see GetFinalRelevancyScore() for details.
+  typedef std::pair<double, int> ScoreMaxRelevance;
+
   ScoredHistoryMatch();  // Required by STL.
 
   // Creates a new match with a raw score calculated for the history item
   // given in |row| with recent visits as indicated in |visits|.  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 is in part determined by whether the matches occur at word
   // boundaries, the locations of which are stored in |word_starts|.  For some
   // terms, it's appropriate to look for the word boundary within the term.
   // For instance, the term ".net" should look for a word boundary at the "n".
@@ skipping 34 matching lines @@
   // end_pos == string::npos is treated as end_pos = length of string.
   static TermMatches FilterTermMatchesByWordStarts(
       const TermMatches& term_matches,
       const WordStarts& terms_to_word_starts_offsets,
       const WordStarts& word_starts,
       size_t start_pos,
       size_t end_pos);
 
  private:
   friend class ScoredHistoryMatchTest;
+  FRIEND_TEST_ALL_PREFIXES(ScoredHistoryMatchTest, GetFinalRelevancyScore);
   FRIEND_TEST_ALL_PREFIXES(ScoredHistoryMatchTest, ScoringBookmarks);
   FRIEND_TEST_ALL_PREFIXES(ScoredHistoryMatchTest, ScoringDiscountFrecency);
   FRIEND_TEST_ALL_PREFIXES(ScoredHistoryMatchTest, ScoringScheme);
   FRIEND_TEST_ALL_PREFIXES(ScoredHistoryMatchTest, ScoringTLD);
 
   // The number of days of recency scores to precompute.
   static const int kDaysToPrecomputeRecencyScoresFor;
 
   // The number of raw term score buckets use; raw term scores
   // greater this are capped at the score of the largest bucket.
@@ skipping 24 matching lines @@
   // Examines the first kMaxVisitsToScore and return a score (higher is
   // better) based the rate of visits, whether the page is bookmarked, and
   // how often those visits are typed navigations (i.e., explicitly
   // invoked by the user).  |now| is passed in to avoid unnecessarily
   // recomputing it frequently.
   static float GetFrequency(const base::Time& now,
                             const bool bookmarked,
                             const VisitInfoVector& visits);
 
   // Combines the two component scores into a final score that's
-  // an appropriate value to use as a relevancy score.
+  // an appropriate value to use as a relevancy score. Scoring buckets are
+  // specified through |hqp_relevance_buckets|. Please see the function
+  // implementation for more details.
   static float GetFinalRelevancyScore(
       float topicality_score,
-      float frequency_score);
+      float frequency_score,
+      const std::vector<ScoreMaxRelevance>& hqp_relevance_buckets);
+
+  // Initializes the HQP experimental params,

[Mark P, 2015/02/18 00:03:32]

nit: should this be a ":" or "("/")", not a ","?  What experimental params are
not included in the below list?

[Ashok vardhan, 2015/02/18 01:11:21]

Done.

+  // |hqp_experimental_scoring_enabled_|, |topicality_threshold_| and
+  // |hqp_relevance_buckets_| specified through omnibox field trials.

[Mark P, 2015/02/18 00:03:32]

You missed this earlier comment:
By the way, this comment is wrong as written.  In particular, you end up seeing
some of these variables even if hqp_experimental_scoring is not enabled (and you
rely on these settings in the code even when experimental scoring is not
enabled).

[Ashok vardhan, 2015/02/18 01:11:21]

Done.

+  static void InitializeHQPExperimentalParams();
 
   // Sets |also_do_hup_like_scoring_|,
   // |max_assigned_score_for_non_inlineable_matches_|, |bookmark_value_|,
   // |allow_tld_matches_|, and |allow_scheme_matches_| based on the field
   // trial state.
   static void Init();
 
   // An interim score taking into consideration location and completeness
   // of the match.
   int raw_score_;
@@ skipping 49 matching lines @@
   // state.
   static bool also_do_hup_like_scoring_;
 
   // The maximum score that can be assigned to non-inlineable matches.
   // This is useful because often we want inlineable matches to come
   // first (even if they don't sometimes score as well as non-inlineable
   // matches) because if a non-inlineable match comes first than all matches
   // will get demoted later in HistoryQuickProvider to non-inlineable scores.
   // Set to -1 to indicate no maximum score.
   static int max_assigned_score_for_non_inlineable_matches_;
+
+  // True, if we enable hqp experimental scoring.

[Mark P, 2015/02/18 00:03:32]

nit:
True, if we enable hqp experimental scoring.
->
True if hqp experimental scoring is enabled.

[Ashok vardhan, 2015/02/18 01:11:21]

Done.

+  static bool hqp_experimental_scoring_enabled_;
+
+  // |topicality_threshold_| is used to control the topicality scoring.
+  // If |topicality_threshold_| > 0, then URLs with topicality-score < threshold
+  // are given score 0. By default it is initalized to -1.

[Mark P, 2015/02/18 00:03:32]

"score of 0" or "topicality score of 0"?  I think you meant the former.  Yet, it
appears that topicality score of 0 doesn't translate into a final score of 0. 
(With current parameters as you point out, it gets assigned a score of 400.)

[Ashok vardhan, 2015/02/18 01:11:21]

Done.

+  static float topicality_threshold_;
+
+  // |hqp_relevance_buckets_| gives mapping from (topicality*frequency)
+  // to the final relevance scoring. Please see GetFinalRelevancyScore()
+  // for more details and scoring method.
+  static std::vector<ScoreMaxRelevance>* hqp_relevance_buckets_;
+
 };
 typedef std::vector<ScoredHistoryMatch> ScoredHistoryMatches;
 
 }  // namespace history
 
 #endif  // CHROME_BROWSER_HISTORY_SCORED_HISTORY_MATCH_H_