Migrate call sites LoginDisplayHostImpl::default_host to LoginDisplayHost.

chrome/browser/chromeos/login/session/user_session_manager.cc

Index: chrome/browser/chromeos/login/session/user_session_manager.cc
diff --git a/chrome/browser/chromeos/login/session/user_session_manager.cc b/chrome/browser/chromeos/login/session/user_session_manager.cc
index 0a145993d8c347da68a2f27d5198852ce6fd6ee2..305ff991b57406d36c300ef3a286d0b1e4aa9475 100644
--- a/chrome/browser/chromeos/login/session/user_session_manager.cc
+++ b/chrome/browser/chromeos/login/session/user_session_manager.cc
@@ -42,6 +42,7 @@
 #include "chrome/browser/chromeos/login/chrome_restart_request.h"
 #include "chrome/browser/chromeos/login/demo_mode/demo_app_launcher.h"
 #include "chrome/browser/chromeos/login/easy_unlock/easy_unlock_key_manager.h"
+#include "chrome/browser/chromeos/login/existing_user_controller.h"
 #include "chrome/browser/chromeos/login/helper.h"
 #include "chrome/browser/chromeos/login/lock/screen_locker.h"
 #include "chrome/browser/chromeos/login/profile_auth_data.h"
@@ -53,7 +54,6 @@
 #include "chrome/browser/chromeos/login/startup_utils.h"
 #include "chrome/browser/chromeos/login/ui/input_events_blocker.h"
 #include "chrome/browser/chromeos/login/ui/login_display_host.h"
-#include "chrome/browser/chromeos/login/ui/login_display_host_impl.h"
 #include "chrome/browser/chromeos/login/user_flow.h"
 #include "chrome/browser/chromeos/login/users/chrome_user_manager.h"
 #include "chrome/browser/chromeos/login/users/supervised_user_manager.h"
@@ -1181,7 +1181,7 @@ void UserSessionManager::FinalizePrepareProfile(Profile* profile) {
 }
 
 void UserSessionManager::ActivateWizard(const std::string& screen_name) {
-  LoginDisplayHost* host = LoginDisplayHostImpl::default_host();
+  LoginDisplayHost* host = LoginDisplayHost::default_host();
   CHECK(host);
   host->StartWizard(screen_name);
 }
@@ -1271,7 +1271,7 @@ bool UserSessionManager::InitializeUserSession(Profile* profile) {
     }
   }
 
-  DoBrowserLaunch(profile, LoginDisplayHostImpl::default_host());
+  DoBrowserLaunch(profile, LoginDisplayHost::default_host());
   return true;
 }