linux and chromeos: Turn on -Wunused-const-variable.

chrome/browser/chromeos/login/chrome_restart_request.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/chromeos/login/chrome_restart_request.h"
 
 #include <vector>
 
 #include "ash/ash_switches.h"
 #include "base/command_line.h"
@@ skipping 36 matching lines @@
 namespace chromeos {
 
 namespace {
 
 // Increase logging level for Guest mode to avoid LOG(INFO) messages in logs.
 const char kGuestModeLoggingLevel[] = "1";
 
 // Format of command line switch.
 const char kSwitchFormatString[] = " --%s=\"%s\"";
 
-// User name which is used in the Guest session.
-const char kGuestUserName[] = "";
-
 // Derives the new command line from |base_command_line| by doing the following:
 // - Forward a given switches list to new command;
 // - Set start url if given;
 // - Append/override switches using |new_switches|;
 std::string DeriveCommandLine(const GURL& start_url,
                               const CommandLine& base_command_line,
                               const base::DictionaryValue& new_switches,
                               CommandLine* command_line) {
   DCHECK_NE(&base_command_line, command_line);
 
@@ skipping 294 matching lines @@
     // Relaunch chrome without session manager on dev box.
     ReLaunch(command_line);
     return;
   }
 
   // ChromeRestartRequest deletes itself after request sent to session manager.
   (new ChromeRestartRequest(command_line))->Start();
 }
 
 }  // namespace chromeos