Omnibox: Create HistoryQuickProvider new scoring field trial.

chrome/browser/history/scored_history_match.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_HISTORY_SCORED_HISTORY_MATCH_H_
 #define CHROME_BROWSER_HISTORY_SCORED_HISTORY_MATCH_H_
 #pragma once
 
 #include <map>
 #include <set>
@@ skipping 79 matching lines @@
 
   // Pre-calculates days_ago_to_recency_numerator_, used in
   // GetRecencyScore().
   static void FillInDaysAgoToRecencyScoreArray();
 
   // Returns a popularity score based on |typed_count| and
   // |visit_count|.
   static float GetPopularityScore(int typed_count,
                                   int visit_count);
 
+  // Sets use_new_scoring based on command line flags and/or
+  // field trial state.
+  static void InitializeNewScoringField();
+
   // End of functions used only in "new" scoring --------------------------
 
   // An interim score taking into consideration location and completeness
   // of the match.
   int raw_score;
   TermMatches url_matches;  // Term matches within the URL.
   TermMatches title_matches;  // Term matches within the page title.
   bool can_inline;  // True if this is a candidate for in-line autocompletion.
 
   // Pre-computed information to speed up calculating recency scores.
@@ skipping 21 matching lines @@
 
   // Whether to use new-score or old-scoring.  Set in the constructor
   // by examining command line flags.
   static bool use_new_scoring;
 };
 typedef std::vector<ScoredHistoryMatch> ScoredHistoryMatches;
 
 }  // namespace history
 
 #endif  // CHROME_BROWSER_HISTORY_SCORED_HISTORY_MATCH_H_