cros: Do not initialize gaia portal detector if not loading gaia

chrome/browser/ui/webui/chromeos/login/gaia_screen_handler.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/ui/webui/chromeos/login/gaia_screen_handler.h"
 
 #include "ash/system/devicetype_utils.h"
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/guid.h"
@@ skipping 225 matching lines @@
 }
 
 GaiaScreenHandler::~GaiaScreenHandler() {
   if (network_portal_detector_)
     network_portal_detector_->RemoveObserver(this);
 }
 
 void GaiaScreenHandler::MaybePreloadAuthExtension() {
   VLOG(1) << "MaybePreloadAuthExtension";
 
-  if (!network_portal_detector_) {
+  if (!network_portal_detector_ &&
+      !user_manager::UserManager::Get()->IsUserLoggedIn()) {

[xiyuan, 2017/06/06 21:54:29]

Maybe move ShouldLoadGaia() before this and bail out early if it returns false ?

[jdufault, 2017/06/06 21:58:37]

Add a comment explaining why we need this special case.

[Qiang(Joe) Xu, 2017/06/06 22:51:09]

Done.

[Qiang(Joe) Xu, 2017/06/06 22:51:09]

Done.

     NetworkPortalDetectorImpl* detector = new NetworkPortalDetectorImpl(
         g_browser_process->system_request_context(), false);
     detector->set_portal_test_url(GURL(kRestrictiveProxyURL));
     network_portal_detector_.reset(detector);
     network_portal_detector_->AddObserver(this);
     network_portal_detector_->Enable(true);
   }
 
   // If cookies clearing was initiated or |dns_clear_task_running_| then auth
   // extension showing has already been initiated and preloading is pointless.
@@ skipping 717 matching lines @@
 SigninScreenHandlerDelegate* GaiaScreenHandler::Delegate() {
   return signin_screen_handler_->delegate_;
 }
 
 bool GaiaScreenHandler::IsRestrictiveProxy() const {
   return !disable_restrictive_proxy_check_for_test_ &&
          !IsOnline(captive_portal_status_);
 }
 
 }  // namespace chromeos