Remove AppListMixer field trial.

ui/app_list/search_controller.cc

 // Copyright 2013 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.
 
 #include "ui/app_list/search_controller.h"
 
 #include <algorithm>
 #include <memory>
 #include <utility>
 #include <vector>
@@ skipping 94 matching lines @@
   }
 }
 
 void SearchController::InvokeResultAction(SearchResult* result,
                                           int action_index,
                                           int event_flags) {
   // TODO(xiyuan): Hook up with user learning.
   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,
                                    std::unique_ptr<SearchProvider> provider) {
   provider->set_result_changed_callback(base::Bind(
       &SearchController::OnResultsChanged,
       base::Unretained(this)));
   mixer_->AddProviderToGroup(group_id, provider.get());
   providers_.push_back(std::move(provider));
 }
 
 void SearchController::OnResultsChanged() {
   if (dispatching_query_)
     return;
 
   KnownResults known_results;
   if (history_ && history_->IsReady()) {
     history_->GetKnownResults(base::UTF16ToUTF8(search_box_->text()))
         ->swap(known_results);
   }
 
   mixer_->MixAndPublish(is_voice_query_, known_results);
 }
 
 }  // namespace app_list