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

chrome/browser/chromeos/login/existing_user_controller.cc

Index: chrome/browser/chromeos/login/existing_user_controller.cc
diff --git a/chrome/browser/chromeos/login/existing_user_controller.cc b/chrome/browser/chromeos/login/existing_user_controller.cc
index cfe8624c5c0263a32d67c6a4476bca8dba893fed..5dba465893e8eb88b5f4bf2e7f8a733e6cb5aab7 100644
--- a/chrome/browser/chromeos/login/existing_user_controller.cc
+++ b/chrome/browser/chromeos/login/existing_user_controller.cc
@@ -66,9 +66,6 @@ namespace chromeos {
 
 namespace {
 
-// Major version where we still show GSG as "Release Notes" after the update.
-const long int kReleaseNotesTargetRelease = 19;
-
 // URL for account creation.
 const char kCreateAccountURL[] =
     "https://accounts.google.com/NewAccount?service=mail";
@@ -84,9 +81,6 @@ const long int kAuthCacheTransferDelayMs = 2000;
 // Delay for restarting the ui if safe-mode login has failed.
 const long int kSafeModeRestartUiDelayMs = 30000;
 
-// Delay for rebooting machine if TPM critical error was encountered.
-const long int kCriticalErrorRebootDelayMs = 3500;
-
 // Makes a call to the policy subsystem to reload the policy when we detect
 // authentication change.
 void RefreshPoliciesOnUIThread() {