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

chrome/browser/ui/webui/options/managed_user_passphrase_handler.cc

+// 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.
+
+#include "chrome/browser/ui/webui/options/managed_user_passphrase_handler.h"
+
+#include "base/bind.h"
+#include "base/logging.h"
+#include "base/values.h"
+#include "chrome/browser/managed_mode/managed_user_passphrase.h"
+#include "chrome/browser/prefs/pref_service.h"
+#include "chrome/browser/profiles/profile.h"
+#include "chrome/browser/ui/webui/managed_user_passphrase_dialog_webui.h"
+#include "chrome/common/pref_names.h"
+#include "content/public/browser/web_contents.h"
+#include "content/public/browser/web_ui.h"
+#include "grit/generated_resources.h"
+
+namespace options {
+
+ManagedUserPassphraseHandler::ManagedUserPassphraseHandler() {
+}
+
+ManagedUserPassphraseHandler::~ManagedUserPassphraseHandler() {
+}
+
+void ManagedUserPassphraseHandler::InitializeHandler() {
+  Profile* profile = Profile::FromWebUI(web_ui());
+  PrefService* prefs = profile->GetPrefs();
+
+  base::Closure callback = base::Bind(
+      &ManagedUserPassphraseHandler::OnPreferenceChanged,
+      base::Unretained(this));
+
+  registrar_.Init(prefs);
+  registrar_.Add(prefs::kChildLockDisabled, callback);
+}
+
+void ManagedUserPassphraseHandler::RegisterMessages() {
+  web_ui()->RegisterMessageCallback("setPassphrase",
+      base::Bind(&ManagedUserPassphraseHandler::SetLocalPassphrase,
+      base::Unretained(this)));
+    web_ui()->RegisterMessageCallback("displayPassphraseDialog",
+      base::Bind(&ManagedUserPassphraseHandler::DisplayPassphraseDialog,
+      base::Unretained(this)));
+}
+
+void ManagedUserPassphraseHandler::GetLocalizedValues(
+    base::DictionaryValue* localized_strings) {
+  DCHECK(localized_strings);
+
+  static OptionsStringResource resources[] = {
+    { "confirmPassphrase", IDS_CONFIRM_PASSPHRASE_LABEL },
+    { "enterPassphrase", IDS_ENTER_PASSPHRASE_LABEL },
+    { "savePassphrase", IDS_SAVE_PASSPHRASE_BUTTON },
+    { "setPassphraseInstructions", IDS_SET_PASSPHRASE_INSTRUCTIONS },
+  };
+
+  RegisterStrings(localized_strings, resources, arraysize(resources));

[Bernhard Bauer, 2013/01/07 14:20:22]

Could you switch this line with the empty one above? Then they're grouped
together nicely.

+  RegisterTitle(localized_strings, "setPassphraseTitle",
+      IDS_SET_PASSPHRASE_TITLE);
+}
+
+void ManagedUserPassphraseHandler::CorrectPassphraseEntered() {
+  web_ui()->CallJavascriptFunction(callback_function_name_);
+}
+
+void ManagedUserPassphraseHandler::DisplayPassphraseDialog(
+    const base::ListValue* args) {
+  // store the name of the callback function

[Pam (message me for reviews), 2013/01/07 14:51:49]

Capital letter and period please (also below).

+  const base::Value* callbackArg;
+  args->Get(0, &callbackArg);
+  callbackArg->GetAsString(&callback_function_name_);
+  LOG(INFO) << callback_function_name_;

[Pam (message me for reviews), 2013/01/07 14:51:49]

Please remove this, or change it to DLOG, or even better a DVLOG.

+  content::WebContents *web_contents = web_ui()->GetWebContents();
+  ManagedUserPassphraseDialogWebUI::CreateManagedUserPassphraseDialog(
+      web_contents,
+      base::Bind(&ManagedUserPassphraseHandler::CorrectPassphraseEntered,
+      base::Unretained(this)));
+}
+
+void ManagedUserPassphraseHandler::SetLocalPassphrase(
+    const base::ListValue* args) {
+  const base::Value *passphraseArg;
+  args->Get(0, &passphraseArg);
+  std::string passphrase;
+  passphraseArg->GetAsString(&passphrase);
+  PrefService* pref_service = Profile::FromWebUI(web_ui())->GetPrefs();
+  // store a passphrase hash which is derived from the real passphrase
+  std::string encoded_passphrase_hash;
+  ManagedUserPassphrase::GenerateHashFromPassphrase(passphrase,
+      &encoded_passphrase_hash);
+  pref_service->SetString(prefs::kManagedModeLocalPassphrase,
+      encoded_passphrase_hash);
+}
+
+// was used for testing

[Bernhard Bauer, 2013/01/07 14:20:22]

Then remove please :)

+void ManagedUserPassphraseHandler::OnPreferenceChanged() {
+  LOG(INFO) << "Child passphrase pref changed";
+}
+
+}  // namespace options