Fix and re-enable "early restart" feature on ChromeOS.

chrome/browser/chromeos/login/login_utils.cc

Index: chrome/browser/chromeos/login/login_utils.cc
diff --git a/chrome/browser/chromeos/login/login_utils.cc b/chrome/browser/chromeos/login/login_utils.cc
index a6b7c488f7afa5e104842e35404a6fe889fda288..f8612bde921f2cb3e849a3e07d50bf7e4d306ad3 100644
--- a/chrome/browser/chromeos/login/login_utils.cc
+++ b/chrome/browser/chromeos/login/login_utils.cc
@@ -120,9 +120,9 @@ bool NeedRestartToApplyPerSessionFlags(const CommandLine& user_flags) {
 }
 
 bool CanPerformEarlyRestart() {
-  // TODO(alemate): crbug/391357 - temporary disabling early restart before
-  // crbug.com/391793 is fixed.
-  return false;
+  // Desktop build is used for development only. Early restart is not supported.
+  if (!base::SysInfo::IsRunningOnChromeOS())

[Nikita (slow), 2014/07/09 04:04:08]

FYI we can emulate that at least somehow since Guest mode that  requires restart
as well is supported on desktop.

+    return false;
 
   const ExistingUserController* controller =
       ExistingUserController::current_controller();
@@ -351,6 +351,9 @@ void LoginUtilsImpl::DelegateDeleted(LoginUtils::Delegate* delegate) {
 
 bool LoginUtilsImpl::RestartToApplyPerSessionFlagsIfNeed(Profile* profile,
                                                          bool early_restart) {
+  if (ProfileHelper::IsSigninProfile(profile))
+    return false;
+
   if (early_restart && !CanPerformEarlyRestart())
     return false;