Remove AppListMixer field trial.

ui/app_list/search_controller.cc

Index: ui/app_list/search_controller.cc
diff --git a/ui/app_list/search_controller.cc b/ui/app_list/search_controller.cc
index c72080e6ca9d0fbec55eb5cdbb37ff20fd464275..5891341544cf885ddc0f038d7ecb2785ee7fab3d 100644
--- a/ui/app_list/search_controller.cc
+++ b/ui/app_list/search_controller.cc
@@ -112,16 +112,8 @@ void SearchController::InvokeResultAction(SearchResult* result,
   result->InvokeAction(action_index, event_flags);
 }
 
-size_t SearchController::AddGroup(size_t max_results,
-                                  double boost,
-                                  double multiplier) {
-  return mixer_->AddGroup(max_results, boost, multiplier);
-}
-
-size_t SearchController::AddOmniboxGroup(size_t max_results,
-                                         double boost,
-                                         double multiplier) {
-  return mixer_->AddOmniboxGroup(max_results, boost, multiplier);
+size_t SearchController::AddGroup(size_t max_results, double multiplier) {
+  return mixer_->AddGroup(max_results, multiplier);
 }
 
 void SearchController::AddProvider(size_t group_id,