[session_manager] Move user session initialization code out of ExistingUserController

chrome/browser/chromeos/login/supervised/supervised_user_login_flow.cc

Index: chrome/browser/chromeos/login/supervised/supervised_user_login_flow.cc
diff --git a/chrome/browser/chromeos/login/supervised/supervised_user_login_flow.cc b/chrome/browser/chromeos/login/supervised/supervised_user_login_flow.cc
index 0f9a84eab4a7524d8146f30617d9e8bdc2da4f58..3d4bd83836afe1fe0a1cd81b2c7a477ee1e54054 100644
--- a/chrome/browser/chromeos/login/supervised/supervised_user_login_flow.cc
+++ b/chrome/browser/chromeos/login/supervised/supervised_user_login_flow.cc
@@ -5,6 +5,7 @@
 #include "chrome/browser/chromeos/login/supervised/supervised_user_login_flow.h"
 
 #include "base/base64.h"
+#include "base/command_line.h"
 #include "base/logging.h"
 #include "base/metrics/histogram.h"
 #include "base/prefs/pref_registry_simple.h"
@@ -18,6 +19,7 @@
 #include "chrome/browser/chromeos/login/users/chrome_user_manager.h"
 #include "chrome/browser/chromeos/login/users/supervised_user_manager.h"
 #include "chrome/browser/chromeos/login/wizard_controller.h"
+#include "chrome/common/chrome_switches.h"
 #include "chromeos/login/auth/key.h"
 #include "components/user_manager/user_manager.h"
 #include "content/public/browser/browser_thread.h"
@@ -35,6 +37,14 @@ SupervisedUserLoginFlow::SupervisedUserLoginFlow(
 
 SupervisedUserLoginFlow::~SupervisedUserLoginFlow() {}
 
+void SupervisedUserLoginFlow::AppendAdditionalCommandLineSwitches() {
+  user_manager::UserManager* user_manager = user_manager::UserManager::Get();
+  if (user_manager->IsCurrentUserNew()) {
+    // Supervised users should launch into empty desktop on first run.
+    CommandLine::ForCurrentProcess()->AppendSwitch(::switches::kSilentLaunch);
+  }
+}
+
 bool SupervisedUserLoginFlow::CanLockScreen() {
   return true;
 }
@@ -55,10 +65,6 @@ bool SupervisedUserLoginFlow::HandlePasswordChangeDetected() {
   return false;
 }
 
-void SupervisedUserLoginFlow::HandleOAuthTokenStatusChange(
-    user_manager::User::OAuthTokenStatus status) {
-}
-
 void SupervisedUserLoginFlow::OnSyncSetupDataLoaded(
     const std::string& token) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));