Omnibox - Boost Frequency Scores Based on Number of Matching Pages

components/omnibox/browser/omnibox_field_trial.h

 // Copyright 2014 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_OMNIBOX_BROWSER_OMNIBOX_FIELD_TRIAL_H_
 #define COMPONENTS_OMNIBOX_BROWSER_OMNIBOX_FIELD_TRIAL_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 85 matching lines @@
 };
 
 // This class manages the Omnibox field trials.
 class OmniboxFieldTrial {
  public:
   // A mapping that contains multipliers indicating that matches of the
   // specified type should have their relevance score multiplied by the
   // given number.  Omitted types are assumed to have multipliers of 1.0.
   typedef std::map<AutocompleteMatchType::Type, float> DemotionMultipliers;
 
+  // A vector that maps from the number of matching pages to the document
+  // specificity score used in HistoryQuick provider / ScoredHistoryMatch
+  // scoring. The vector is sorted by the size_t (the number of matching pages).
+  // If an entry is omitted, the appropriate value is assumed to be the one in
+  // the later bucket.  For example, with a vector containing {{1, 2.0},
+  // {3, 1.5}}, the score for 2 is inferred to be 1.5.  Values beyond the
+  // end of the vector are assumed to have scores of 1.0.
+  typedef std::vector<std::pair<size_t, double>> NumMatchesScores;
+
   // Do not change these values as they need to be in sync with values
   // specified in experiment configs on the variations server.
   enum EmphasizeTitlesCondition {
     EMPHASIZE_WHEN_NONEMPTY = 0,
     EMPHASIZE_WHEN_TITLE_MATCHES = 1,
     EMPHASIZE_WHEN_ONLY_TITLE_MATCHES = 2,
     EMPHASIZE_NEVER = 3
   };
 
   // ---------------------------------------------------------
@@ skipping 179 matching lines @@
   static bool HQPFreqencyUsesSum();
 
   // Returns the number of visits HQP should use when computing frequency
   // scores.  Returns 10 if the epxeriment isn't active.
   static size_t HQPMaxVisitsToScore();
 
   // Returns the score that should be given to typed transitions.  (The score
   // of non-typed transitions is 1.)  Returns 20 if the experiment isn't active.
   static float HQPTypedValue();
 
+  // Returns NumMatchesScores; see comment by the declaration of it.
+  // Returns an empty NumMatchesScores if the experiment isn't active.
+  static NumMatchesScores HQPNumMatchesScores();
+
   // ---------------------------------------------------------
   // For the HQPNumTitleWords experiment that's part of the
   // bundled omnibox field trial.
 
   // Returns the number of title words that are allowed to contribute
   // to the topicality score.  Words later in the title are ignored.
   // Returns 20 as a default if the experiment isn't active.
   static size_t HQPNumTitleWordsToAllow();
 
   // ---------------------------------------------------------
@@ skipping 60 matching lines @@
   static const char kHQPAllowMatchInSchemeRule[];
   static const char kZeroSuggestRule[];
   static const char kZeroSuggestVariantRule[];
   static const char kSuggestVariantRule[];
   static const char kDisableResultsCachingRule[];
   static const char kMeasureSuggestPollingDelayFromLastKeystrokeRule[];
   static const char kSuggestPollingDelayMsRule[];
   static const char kHQPFixFewVisitsBugRule[];
   static const char kHQPFreqencyUsesSumRule[];
   static const char kHQPMaxVisitsToScoreRule[];
+  static const char kHQPNumMatchesScoresRule[];
   static const char kHQPNumTitleWordsRule[];
   static const char kHQPAlsoDoHUPLikeScoringRule[];
   static const char kHUPSearchDatabaseRule[];
   static const char kPreventUWYTDefaultForNonURLInputsRule[];
   static const char kKeywordRequiresRegistryRule[];
   static const char kKeywordRequiresPrefixMatchRule[];
   static const char kKeywordScoreForSufficientlyCompleteMatchRule[];
   static const char kHQPAllowDupMatchesForScoringRule[];
   static const char kEmphasizeTitlesRule[];
 
@@ skipping 36 matching lines @@
   // prioritize different wildcard contexts, see the implementation.  How to
   // interpret the value is left to the caller; this is rule-dependent.
   static std::string GetValueForRuleInContext(
       const std::string& rule,
       metrics::OmniboxEventProto::PageClassification page_classification);
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(OmniboxFieldTrial);
 };
 
 #endif  // COMPONENTS_OMNIBOX_BROWSER_OMNIBOX_FIELD_TRIAL_H_