Omnibox: Add Field Trial to Create UWYT When Inlining

chrome/browser/autocomplete/history_url_provider.h

Index: chrome/browser/autocomplete/history_url_provider.h
diff --git a/chrome/browser/autocomplete/history_url_provider.h b/chrome/browser/autocomplete/history_url_provider.h
index 759146287170c7db0f50f59c31556b23a9136564..0fd950d8a09f3e0ec5a405e6ab9a04d0112651ea 100644
--- a/chrome/browser/autocomplete/history_url_provider.h
+++ b/chrome/browser/autocomplete/history_url_provider.h
@@ -245,14 +245,20 @@ class HistoryURLProvider : public HistoryProvider {
 
   // May promote either the what you typed match or first history match in
   // params->matches to the front of |matches_|, depending on the value of
-  // params->promote_type.
-  void PromoteMatchIfNecessary(const HistoryURLProviderParams& params);
+  // params->promote_type.  Also, depending on a field trial state, if it
+  // promotes the first history match, it may decide to append the what you
+  // typed matche immediately after.
+  void PromoteMatchesIfNecessary(const HistoryURLProviderParams& params);
 
   // Dispatches the results to the autocomplete controller. Called on the
   // main thread by ExecuteWithDB when the results are available.
   // Frees params_gets_deleted on exit.
   void QueryComplete(HistoryURLProviderParams* params_gets_deleted);
 
+  // Returns whether we should consider showing the what you typed match.
+  static bool HaveWhatYouTypedMatch(const VisitClassifier& classifier,
+                                    const HistoryURLProviderParams& params);
+
   // Looks up the info for params->what_you_typed_match in the DB.  If found,
   // fills in the title, promotes the match's priority to that of an inline
   // autocomplete match (maybe it should be slightly better?), and places it on