Migrate call sites LoginDisplayHostImpl::default_host to LoginDisplayHost.

chrome/browser/ui/webui/chromeos/login/signin_screen_handler.cc

Index: chrome/browser/ui/webui/chromeos/login/signin_screen_handler.cc
diff --git a/chrome/browser/ui/webui/chromeos/login/signin_screen_handler.cc b/chrome/browser/ui/webui/chromeos/login/signin_screen_handler.cc
index 5360f4ad4b4af8c3f1a102a9440e58645e89196f..81f1ddb7b097853bde190550ec149ecf6149ced2 100644
--- a/chrome/browser/ui/webui/chromeos/login/signin_screen_handler.cc
+++ b/chrome/browser/ui/webui/chromeos/login/signin_screen_handler.cc
@@ -998,7 +998,7 @@ void SigninScreenHandler::HandleShowSupervisedUserCreationScreen() {
     LOG(ERROR) << "Managed users not allowed.";
     return;
   }
-  LoginDisplayHostImpl::default_host()->
+  LoginDisplayHost::default_host()->
       StartWizard(WizardController::kSupervisedUserCreationScreenName);
 }
 
@@ -1081,7 +1081,7 @@ void SigninScreenHandler::HandleToggleKioskEnableScreen() {
   policy::BrowserPolicyConnectorChromeOS* connector =
       g_browser_process->platform_part()->browser_policy_connector_chromeos();
   if (delegate_ && !connector->IsEnterpriseManaged() &&
-      LoginDisplayHostImpl::default_host()) {
+      LoginDisplayHost::default_host()) {
     delegate_->ShowKioskEnableScreen();
   }
 }
@@ -1142,7 +1142,7 @@ void SigninScreenHandler::HandleSignOutUser() {
 }
 
 void SigninScreenHandler::HandleOpenProxySettings() {
-  LoginDisplayHostImpl::default_host()->OpenProxySettings();
+  LoginDisplayHost::default_host()->OpenProxySettings();
 }
 
 void SigninScreenHandler::HandleLoginVisible(const std::string& source) {