Purge the App Launcher code from Windows.

chrome/common/pref_names.cc

 // Copyright (c) 2012 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/common/pref_names.h"
 
 #include "base/macros.h"
 #include "build/build_config.h"
 #include "chrome/common/pref_font_webkit_names.h"
 
@@ skipping 2058 matching lines @@
 const char kAppLauncherHasBeenEnabled[] =
     "apps.app_launcher.has_been_enabled";
 
 // An enum indicating how the app launcher was enabled. E.g., via webstore, app
 // install, command line, etc. For UMA.
 const char kAppListEnableMethod[] = "app_list.how_enabled";
 
 // The time that the app launcher was enabled. Cleared when UMA is recorded.
 const char kAppListEnableTime[] = "app_list.when_enabled";
 
-// The last time the app list was launched.
-const char kAppListLastLaunchTime[] = "app_list.last_launch";
-
 #if defined(OS_MACOSX)
 // Integer representing the version of the app launcher shortcut installed on
 // the system. Incremented, e.g., when embedded icons change.
 const char kAppLauncherShortcutVersion[] = "apps.app_launcher.shortcut_version";
 #endif
 
 // A boolean identifying if we should show the app launcher promo or not.
 const char kShowAppLauncherPromo[] = "app_launcher.show_promo";
 
 // A dictionary that tracks the Drive app to Chrome app mapping. The key is
@@ skipping 150 matching lines @@
 #endif
 
 // The base64-encoded representation of the public key to use to validate origin
 // trial token signatures.
 const char kOriginTrialPublicKey[] = "origin_trials.public_key";
 
 // A list of origin trial features to disable by policy.
 const char kOriginTrialDisabledFeatures[] = "origin_trials.disabled_features";
 
 }  // namespace prefs