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

chrome/browser/managed_mode/managed_user_passphrase.h

Index: chrome/browser/managed_mode/managed_user_passphrase.h
diff --git a/chrome/browser/managed_mode/managed_user_passphrase.h b/chrome/browser/managed_mode/managed_user_passphrase.h
new file mode 100644
index 0000000000000000000000000000000000000000..b8056ebcd50a43e8f19af664c521df7d6e603bde
--- /dev/null
+++ b/chrome/browser/managed_mode/managed_user_passphrase.h
@@ -0,0 +1,27 @@
+// 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.
+
+#ifndef CHROME_BROWSER_MANAGED_MODE_MANAGED_USER_PASSPHRASE_H_
+#define CHROME_BROWSER_MANAGED_MODE_MANAGED_USER_PASSPHRASE_H_
+
+#include <string>
+
+#include "base/basictypes.h"
+
+class ManagedUserPassphrase {
+ public:
+  explicit ManagedUserPassphrase(const std::string &salt);
+  ~ManagedUserPassphrase();
+  std::string GetSalt();
+  void GenerateHashFromPassphrase(const std::string& passphrase,
+      std::string* encoded_passphrase_hash);
+ private:
+  void GetPassphraseHash(const std::string& passphrase,
+      std::string* passphrase_hash);
+  void GenerateRandomSalt();
+  std::string salt_;
+  DISALLOW_COPY_AND_ASSIGN(ManagedUserPassphrase);
+};
+
+#endif  // CHROME_BROWSER_MANAGED_MODE_MANAGED_USER_PASSPHRASE_H_