Add a lock to the managed user settings page and require authentication for unlocking.

chrome/browser/resources/managed_user_passphrase_dialog.css

+/* Copyright (c) 2012 The Chromium Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file. */
+
+#managed-mode-passphrase-page {
+  min-width: 350px;
+}
+
+#chrome-kid-logo {
+  background-image: url('chrome_kid.png');
+  height: 68px;
+  width: 65px;
+}
+
+#instructions,
+#entry {
+  padding: 5px 15px;
+}
+
+#unlock {
+  float: right;
+}
+
+#buttons {
+  padding: 15px 15px;
+}
+
+#passphrase-entry:invalid {
+  background-color: pink;
+}
+
+#incorrect-passphrase-warning {
+  color: red;
+  font-weight: bold;
+  padding: 5px 15px;

[Bernhard Bauer, 2013/01/08 17:43:14]

Can you move this into the selector above as well?

[Adrian Kuegel, 2013/01/09 12:10:05]

Done.

+}