Omnibox: Create DemoteByType Experiment

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 <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;
+
   // 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 83 matching lines @@
   // query suggestions less aggressively so that they don't inline.
   static bool SearchHistoryPreventInlining(
       AutocompleteInput::PageClassification current_page_classification);
 
   // Returns true if the user is in the experiment group that, given the
   // provided |current_page_classification| context, disables all query
   // suggestions from search history.
   static bool SearchHistoryDisable(
       AutocompleteInput::PageClassification current_page_classification);
 
+  // ---------------------------------------------------------
+  // For the DemoteByType experiment that's part of the bundled omnibox field
+  // 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);
+
  private:
   FRIEND_TEST_ALL_PREFIXES(OmniboxFieldTrialTest, GetValueForRuleInContext);
 
   // 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
   // applying the rule are.  For example, the value of a SearchHistory rule
   // in the context of a search results page might indicate that we should
   // prevent search history matches from inlining.
   //
   // This function returns the value associated with the |rule| that applies
   // in the current context (which currently only consists of
   // |page_classification| but will soon contain other features, some not
   // passed in as parameters, such as whether Instant Extended is enabled).
   // If no such rule exists in the current context, looks for that rule in
   // the global context and return its value if found.  If the rule remains
   // unfound in the global context, returns the empty string.  For more
   // details, 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_