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

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

Index: chrome/browser/ui/webui/options/managed_user_settings_handler.cc
diff --git a/chrome/browser/ui/webui/options/managed_user_settings_handler.cc b/chrome/browser/ui/webui/options/managed_user_settings_handler.cc
index 0af71b88b3e3f4d9aab78df9fb74211cef3d1932..a528e9eca72cdabc575c735a20f154ebef960bab 100644
--- a/chrome/browser/ui/webui/options/managed_user_settings_handler.cc
+++ b/chrome/browser/ui/webui/options/managed_user_settings_handler.cc
@@ -8,10 +8,13 @@
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "base/metrics/histogram.h"
+#include "base/prefs/pref_service.h"
 #include "base/time.h"
 #include "base/values.h"
 #include "chrome/browser/first_run/first_run.h"
+#include "chrome/browser/profiles/profile.h"
 #include "chrome/common/chrome_switches.h"
+#include "chrome/common/pref_names.h"
 #include "content/public/browser/user_metrics.h"
 #include "content/public/browser/web_ui.h"
 #include "grit/generated_resources.h"
@@ -27,9 +30,23 @@ ManagedUserSettingsHandler::ManagedUserSettingsHandler() {
 ManagedUserSettingsHandler::~ManagedUserSettingsHandler() {
 }
 
+void ManagedUserSettingsHandler::InitializeHandler() {
+  passphrase_.Init(
+      prefs::kManagedModeLocalPassphrase,
+      Profile::FromWebUI(web_ui())->GetPrefs(),
+      base::Bind(&ManagedUserSettingsHandler::OnLocalPassphraseChanged,
+                 base::Unretained(this)));
+}
+
 void ManagedUserSettingsHandler::InitializePage() {
   start_time_ = base::TimeTicks::Now();
   content::RecordAction(UserMetricsAction("ManagedMode_OpenSettings"));
+  PrefService* pref_service = Profile::FromWebUI(web_ui())->GetPrefs();
+  base::FundamentalValue is_passphrase_set(!pref_service->GetString(
+      prefs::kManagedModeLocalPassphrase).empty());
+  web_ui()->CallJavascriptFunction(
+      "ManagedUserSettings.initializeSetPassphraseButton",
+      is_passphrase_set);
 }
 
 void ManagedUserSettingsHandler::GetLocalizedValues(
@@ -37,6 +54,8 @@ void ManagedUserSettingsHandler::GetLocalizedValues(
   DCHECK(localized_strings);
 
   static OptionsStringResource resources[] = {
+    // Unlock the settings page to allow editing.
+    { "unlockSettings", IDS_UNLOCK_PASSPHRASE_BUTTON },
     // Installed content packs.
     { "installedContentPacks", IDS_INSTALLED_CONTENT_PACKS_LABEL },
     { "getContentPacks", IDS_GET_CONTENT_PACKS_BUTTON },
@@ -82,4 +101,10 @@ void ManagedUserSettingsHandler::SaveMetrics(const ListValue* args) {
   }
 }
 
+void ManagedUserSettingsHandler::OnLocalPassphraseChanged() {
+  base::FundamentalValue is_passphrase_set(!passphrase_.GetValue().empty());
+  web_ui()->CallJavascriptFunction("ManagedUserSettings.passphraseChanged",
+                                   is_passphrase_set);
+}
+
 }  // namespace options