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

1) Early restart is disabled in "Chrome for ChromeOS" desktop build.
2) Ignore signin profile.

The first change simplifies development.
The second fixes the problem "user session cannot be ended if both
owner and current user both have (different) flags set."

BUG=391357
TEST=none

Review URL: https://codereview.chromium.org/378893003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@281989 0039d316-1c4b-4281-b951-d872f2087c98

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())
+    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;