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 223 matching lines @@
   DCHECK(network_state_informer_.get());
   set_call_js_prefix(kJsScreenPath);
 }
 
 GaiaScreenHandler::~GaiaScreenHandler() {
   if (network_portal_detector_)
     network_portal_detector_->RemoveObserver(this);
 }
 
 void GaiaScreenHandler::MaybePreloadAuthExtension() {
+  // We shall not have network portal detector initialized, which unnecessarily
+  // polls captive portal checking URL if we don't need to load gaia.

[jdufault, 2017/06/06 23:23:00]

Please add a link to go/bad-portal here.

// Don't create network portal detector if we don't need to load gaia. See
go/bad-portal for more context.

[Qiang(Joe) Xu, 2017/06/06 23:46:51]

Done.

+  if (!signin_screen_handler_->ShouldLoadGaia())
+    return;
+
   VLOG(1) << "MaybePreloadAuthExtension";
 
   if (!network_portal_detector_) {
     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.
-  if (signin_screen_handler_->ShouldLoadGaia() && !gaia_silent_load_ &&
-      !cookies_cleared_ && !dns_clear_task_running_ &&
+  if (!gaia_silent_load_ && !cookies_cleared_ && !dns_clear_task_running_ &&
       network_state_informer_->state() == NetworkStateInformer::ONLINE) {
     gaia_silent_load_ = true;
     gaia_silent_load_network_ = network_state_informer_->network_path();
     LoadAuthExtension(true /* force */, false /* offline */);
   }
 }
 
 void GaiaScreenHandler::DisableRestrictiveProxyCheckForTest() {
   disable_restrictive_proxy_check_for_test_ = true;
 }
@@ skipping 705 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