Added flag --enable-new-app-list-mixer.

ui/app_list/search/mixer.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/mixer.h"
 
 #include <algorithm>
 #include <map>
 #include <set>
 #include <string>
 #include <vector>
 
+#include "base/command_line.h"
 #include "base/metrics/field_trial.h"
+#include "ui/app_list/app_list_switches.h"
 #include "ui/app_list/search_provider.h"
 #include "ui/app_list/search_result.h"
 
 namespace app_list {
 
 namespace {
 
 // Maximum number of results to show. Ignored if the AppListMixer field trial is
 // "Blended".
 const size_t kMaxResults = 6;
@@ skipping 12 matching lines @@
   target->set_title(source.title());
   target->set_title_tags(source.title_tags());
   target->set_details(source.details());
   target->set_details_tags(source.details_tags());
 }
 
 // Returns true if the "AppListMixer" trial is set to "Blended". This is an
 // experiment on the new Mixer logic that allows results from different groups
 // to be blended together, rather than stratified.
 bool IsBlendedMixerTrialEnabled() {
+  // Note: It's important to query the field trial state first, to ensure that
+  // UMA reports the correct group.
   const std::string group_name =
       base::FieldTrialList::FindFullName(kAppListMixerFieldTrialName);
+
+  if (base::CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kDisableNewAppListMixer)) {
+    return false;
+  }
+
+  if (base::CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kEnableNewAppListMixer)) {
+    return true;
+  }
+
   return group_name == kAppListMixerFieldTrialEnabled;
 }
 
 }  // namespace
 
 Mixer::SortData::SortData() : result(NULL), score(0.0) {
 }
 
 Mixer::SortData::SortData(SearchResult* result, double score)
     : result(result), score(score) {
@@ skipping 258 matching lines @@
   results->swap(final);
 }
 
 void Mixer::FetchResults(bool is_voice_query,
                          const KnownResults& known_results) {
   for (auto* group : groups_)
     group->FetchResults(is_voice_query, known_results);
 }
 
 }  // namespace app_list