Fix flaky Kiosk browser_tests failing on wrong widget opacity.

chrome/browser/chromeos/login/ui/webui_login_view.cc

Index: chrome/browser/chromeos/login/ui/webui_login_view.cc
diff --git a/chrome/browser/chromeos/login/ui/webui_login_view.cc b/chrome/browser/chromeos/login/ui/webui_login_view.cc
index 77428688c66a05ba2a90611aef612f22ee1a3bc8..236fcaeca4c158305633721e187bc9ac26c99748 100644
--- a/chrome/browser/chromeos/login/ui/webui_login_view.cc
+++ b/chrome/browser/chromeos/login/ui/webui_login_view.cc
@@ -321,6 +321,7 @@ void WebUILoginView::SetStatusAreaVisible(bool visible) {
       ash::Shell::GetInstance()->HasPrimaryStatusArea()) {
     ash::SystemTray* tray = ash::Shell::GetInstance()->GetPrimarySystemTray();
     tray->SetVisible(visible);
+    tray->GetWidget()->SetOpacity(visible ? 1.0 : 0.0);
     if (visible) {
       // Tray may have been initialized being hidden.
       tray->GetWidget()->Show();