Adding knobs on HQP provider.

chrome/browser/history/scored_history_match.h

Index: chrome/browser/history/scored_history_match.h
diff --git a/chrome/browser/history/scored_history_match.h b/chrome/browser/history/scored_history_match.h
index 15a37e7bd73673dc4efe2ca93a5e29a06d3e8d59..52fac2db2a5188c24446caf9b3a6cdabb3827d37 100644
--- a/chrome/browser/history/scored_history_match.h
+++ b/chrome/browser/history/scored_history_match.h
@@ -83,6 +83,7 @@ class ScoredHistoryMatch : public history::HistoryMatch {
 
  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);
@@ -128,9 +129,34 @@ class ScoredHistoryMatch : public history::HistoryMatch {
 
   // Combines the two component scores into a final score that's
   // an appropriate value to use as a relevancy score.
+  typedef std::pair<double, int> ScoreMaxRelevance;
+
   static float GetFinalRelevancyScore(
       float topicality_score,
-      float frequency_score);
+      float frequency_score,
+      std::vector<ScoreMaxRelevance>& hqp_relevance_buckets);
+
+  // Initializes the HQP experimental params.
+  // If the experimental scoring is enabled, it sets:
+  //
+  // 1. hqp_experimental to true. Default value is set to false.
+  //
+  // 2. It initializes the topicality_threshold_, and hqp_scoring from the
+  //    finch experiment params.
+  //
+  // 3. topicality_threshold_ is used to control the topicality scoring.
+  // If topicality_threshold > 0, then URLs with topicality score < threshold,
+  // are given score 0. It is initalized to -1;
+  //
+  // 4. hqp_relevance_buckets_, buckets that gives the mapping from
+  // (topicality*frequency) to the final relevance scoring.
+  // Please see GetFinalRelevancyScore() for more details and scoring method.
+  bool hqp_experimental_scoring_enabled_;
+  float topicality_threshold_;
+
+  std::vector<ScoreMaxRelevance> hqp_relevance_buckets_;
+
+  void InitializeHQPExperimentalParams();
 
   // Sets |also_do_hup_like_scoring_|,
   // |max_assigned_score_for_non_inlineable_matches_|, |bookmark_value_|,