Don't demote top match for certain match types.

chrome/browser/omnibox/omnibox_field_trial.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_OMNIBOX_OMNIBOX_FIELD_TRIAL_H_
 #define CHROME_BROWSER_OMNIBOX_OMNIBOX_FIELD_TRIAL_H_
 
 #include <map>
+#include <set>
 #include <string>
 #include <vector>
 
 #include "base/basictypes.h"
 #include "base/gtest_prod_util.h"
 #include "chrome/browser/autocomplete/autocomplete_input.h"
 #include "chrome/common/autocomplete_match_type.h"
 
 // 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 set of types that should not be demoted when they are the top match.
+  typedef std::set<AutocompleteMatchType::Type> UndemotableTopMatchTypes;
+
   // Creates the static field trial groups.
   // *** MUST NOT BE CALLED MORE THAN ONCE. ***
   static void ActivateStaticTrials();
 
   // Activates all dynamic field trials.  The main difference between
   // the autocomplete dynamic and static field trials is that the former
   // don't require any code changes on the Chrome side as they are controlled
   // on the server side.  Chrome binary simply propagates all necessary
   // information through the X-Chrome-Variations header.
   // This method, unlike ActivateStaticTrials(), may be called multiple times.
@@ skipping 106 matching lines @@
   // trial.
 
   // If the user is in an experiment group that, in the provided
   // |current_page_classification| context, demotes the relevance scores
   // of certain types of matches, populates the |demotions_by_type| map
   // appropriately.  Otherwise, clears |demotions_by_type|.
   static void GetDemotionsByType(
       AutocompleteInput::PageClassification current_page_classification,
       DemotionMultipliers* demotions_by_type);
 
+  // Get the set of types that should not be demoted if they are the top
+  // match.
+  static UndemotableTopMatchTypes GetUndemotableTopTypes(
+      AutocompleteInput::PageClassification current_page_classification);
+
   // ---------------------------------------------------------
   // For the ReorderForLegalDefaultMatch experiment that's part of the
   // bundled omnibox field trial.
 
   // Returns true if the omnibox will reorder matches, in the provided
   // |current_page_classification| context so that a match that's allowed to
   // be the default match will appear first.  This means AutocompleteProviders
   // can score matches however they desire without regard to making sure the
   // top match when all the matches from all providers are merged is a legal
   // default match.
   static bool ReorderForLegalDefaultMatch(
       AutocompleteInput::PageClassification current_page_classification);
 
   // ---------------------------------------------------------
   // Exposed publicly for the sake of unittests.
   static const char kBundledExperimentFieldTrialName[];
   // Rule names used by the bundled experiment.
   static const char kShortcutsScoringMaxRelevanceRule[];
   static const char kSearchHistoryRule[];
   static const char kDemoteByTypeRule[];
+  static const char kUndemotableTopTypeRule[];
   static const char kReorderForLegalDefaultMatchRule[];
   // Rule values.
   static const char kReorderForLegalDefaultMatchRuleEnabled[];
 
  private:
   friend class OmniboxFieldTrialTest;
 
   // The bundled omnibox experiment comes with a set of parameters
   // (key-value pairs).  Each key indicates a certain rule that applies in
   // a certain context.  The value indicates what the consequences of
@@ skipping 10 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,
       AutocompleteInput::PageClassification page_classification);
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(OmniboxFieldTrial);
 };
 
 #endif  // CHROME_BROWSER_OMNIBOX_OMNIBOX_FIELD_TRIAL_H_