Add UMA to track app launcher discoverability.

chrome/browser/ui/app_list/app_list_service.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 "chrome/browser/ui/app_list/app_list_service.h"
 
 #include "base/command_line.h"
 #include "base/metrics/histogram.h"
 #include "base/prefs/pref_registry_simple.h"
 #include "base/process/process_info.h"
@@ skipping 73 matching lines @@
 // static
 void AppListService::RegisterPrefs(PrefRegistrySimple* registry) {
   registry->RegisterInt64Pref(prefs::kLastAppListLaunchPing, 0);
   registry->RegisterIntegerPref(prefs::kAppListLaunchCount, 0);
   registry->RegisterInt64Pref(prefs::kLastAppListAppLaunchPing, 0);
   registry->RegisterIntegerPref(prefs::kAppListAppLaunchCount, 0);
   registry->RegisterStringPref(prefs::kAppListProfile, std::string());
   registry->RegisterBooleanPref(prefs::kRestartWithAppList, false);
   registry->RegisterBooleanPref(prefs::kAppLauncherIsEnabled, false);
   registry->RegisterBooleanPref(prefs::kAppLauncherHasBeenEnabled, false);
+  registry->RegisterIntegerPref(prefs::kAppListEnableMethod,
+                                ENABLE_NOT_RECORDED);
+  registry->RegisterInt64Pref(prefs::kAppListEnableTime, 0);
 
 #if defined(OS_MACOSX)
   registry->RegisterIntegerPref(prefs::kAppLauncherShortcutVersion, 0);
 #endif
 
   // Identifies whether we should show the app launcher promo or not.
   // Note that a field trial also controls the showing, so the promo won't show
   // unless the pref is set AND the field trial is set to a proper group.
   registry->RegisterBooleanPref(prefs::kShowAppLauncherPromo, true);
 }
@@ skipping 15 matching lines @@
       break;
     case WARM_START_FAST:
       UMA_HISTOGRAM_LONG_TIMES("Startup.ShowAppListWarmStartFast", elapsed);
       break;
   }
 
   RecordStartupInfo(startup, start_time);
   Get(chrome::HOST_DESKTOP_TYPE_NATIVE)->SetAppListNextPaintCallback(
       RecordFirstPaintTiming);
 }