Update screen locker UI to match webui login

chrome/browser/chromeos/login/screen_lock_view.cc

Index: chrome/browser/chromeos/login/screen_lock_view.cc
diff --git a/chrome/browser/chromeos/login/screen_lock_view.cc b/chrome/browser/chromeos/login/screen_lock_view.cc
index 00f88e8139f11dd79180368809a7b091820226b5..91a3ff382eb65d2c1832bc42ad6423def991c8ee 100644
--- a/chrome/browser/chromeos/login/screen_lock_view.cc
+++ b/chrome/browser/chromeos/login/screen_lock_view.cc
@@ -124,13 +124,10 @@ void ScreenLockView::Init() {
                             false,  // is_login
                             true);  // need_background
   main_ = new views::View();
-  // Use rounded rect background.
-  views::Painter* painter =
-      CreateWizardPainter(&BorderDefinition::kUserBorder);
-
   main_->set_background(
-      views::Background::CreateBackgroundPainter(true, painter));
-  main_->set_border(CreateWizardBorder(&BorderDefinition::kUserBorder));
+      views::Background::CreateVerticalGradientBackground(
+          BorderDefinition::kUserBorder.top_color,
+          BorderDefinition::kUserBorder.bottom_color));
 
   // Password field.
   password_field_ = new PasswordField();