Add a set passphrase dialog for managed user accounts.

chrome/browser/resources/options/managed_user_settings.js

Index: chrome/browser/resources/options/managed_user_settings.js
diff --git a/chrome/browser/resources/options/managed_user_settings.js b/chrome/browser/resources/options/managed_user_settings.js
index 1151e9f631dc6b5d6b9588cd4c93a714e6cf29ca..9fb76aaf15bc26d552bb4bf5febc308dfa5151a1 100644
--- a/chrome/browser/resources/options/managed_user_settings.js
+++ b/chrome/browser/resources/options/managed_user_settings.js
@@ -47,14 +47,21 @@ cr.define('options', function() {
       };
 
       $('set-passphrase').onclick = function() {
-        // TODO(bauerb): Set passphrase
+        OptionsPage.navigateToPage('setPassphrase');
       };
     },
   };
 
+  var ManagedUserSettingsForTesting = {
+    getSetPassphraseButton: function() {
+      return $('set-passphrase');
+    }
+  };
+
    // Export
   return {
-    ManagedUserSettings: ManagedUserSettings
+    ManagedUserSettings: ManagedUserSettings,
+    ManagedUserSettingsForTesting: ManagedUserSettingsForTesting
   };
 });