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

ui/app_list/search/mixer.cc

Index: ui/app_list/search/mixer.cc
diff --git a/ui/app_list/search/mixer.cc b/ui/app_list/search/mixer.cc
index 8bcd8c7e385a6fb5ff84b86f44b81d5c222ed109..3034a0d380dd38131baff074c26d44020d57fae7 100644
--- a/ui/app_list/search/mixer.cc
+++ b/ui/app_list/search/mixer.cc
@@ -10,7 +10,9 @@
 #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"
 
@@ -43,8 +45,21 @@ void UpdateResult(const SearchResult& source, SearchResult* target) {
 // 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;
 }