Adding knobs on HQP provider.

components/omnibox/omnibox_field_trial.h

Index: components/omnibox/omnibox_field_trial.h
diff --git a/components/omnibox/omnibox_field_trial.h b/components/omnibox/omnibox_field_trial.h
index 5a439e2f384a6dd62e2d1a5ceba56938d58b8325..6998768f90cd6cf42009a94fcf0498f913cb03b9 100644
--- a/components/omnibox/omnibox_field_trial.h
+++ b/components/omnibox/omnibox_field_trial.h
@@ -270,6 +270,27 @@ class OmniboxFieldTrial {
                                         int* polling_delay_ms);
 
   // ---------------------------------------------------------
+  // For HQP scoring related experiments to control the topicality and scoring
+  // ranges of relevancy scores.
+
+  // Returns true if HQP experimental scoring is enabled. Returns false if
+  // |kHQPExperimentalScoringEnabledParam| is not specified in the field trial.
+  static bool HQPExperimentalScoringEnabled();
+
+  // Returns the scoring buckets for HQP experiments. Returns empty string
+  // in case |kHQPExperimentalScoringBucketsParam| is specified in the field

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

This sentence is wrong in two ways:
(1) you meant "is not specified"
(2) you missed my earlier correction that you return the empty string even if it
is specified by the enabled param is not specified.

This second comment also applies below.

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

Done.

+  // trial. Scoring buckets are stored in string form giving mapping from
+  // (topicality_score, frequency_score) to final relevance score.
+  // Please see GetRelevancyScore() under
+  // chrome/browser/history::ScoredHistoryMatch for details.
+  static std::string HQPExperimentalScoringBuckets();
+
+  // Returns the topicality threshold for HQP experiments. Returns -1 if
+  // |kHQPExperimentalScoringTopicalityThresholdParam| is not specified in the
+  // field trial.
+  static float HQPExperimentalTopicalityThreshold();
+
+  // ---------------------------------------------------------
   // Exposed publicly for the sake of unittests.
   static const char kBundledExperimentFieldTrialName[];
   // Rule names used by the bundled experiment.
@@ -298,6 +319,11 @@ class OmniboxFieldTrial {
   static const char kHUPNewScoringVisitedCountHalfLifeTimeParam[];
   static const char kHUPNewScoringVisitedCountScoreBucketsParam[];
 
+  // Parameter names used by the HQP experimental scoring experiments.
+  static const char kHQPExperimentalScoringEnabledParam[];
+  static const char kHQPExperimentalScoringBucketsParam[];
+  static const char kHQPExperimentalScoringTopicalityThresholdParam[];
+
   // The amount of time to wait before sending a new suggest request after the
   // previous one unless overridden by a field trial parameter.
   // Non-const because some unittests modify this value.