[cros,rlz] Remove RLZ checkbox from OOBE UI.

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/basictypes.h"
 
 namespace prefs {
 
@@ skipping 2148 matching lines @@
 // Tracks the time of the last shown warning. Used to reset
 // |network_profile.warnings_left| after a silence period.
 const char kNetworkProfileLastWarningTime[] =
     "network_profile.last_warning_time";
 
 // 64-bit serialization of the time last policy usage statistics were collected
 // by UMA_HISTOGRAM_ENUMERATION.
 const char kLastPolicyStatisticsUpdate[] = "policy.last_statistics_update";
 
 #if defined(OS_CHROMEOS)
-// Indicates whether the RLZ tracking has been enabled by user.
-const char kRLZEnabled[] = "rlz.enabled";
-
 // The RLZ brand code, if enabled.
 const char kRLZBrand[] = "rlz.brand";
 #endif
 
 }  // namespace prefs