Create a ManagedModeNavigationObserver only for managed users.

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

 // Copyright (c) 2013 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_set_passphrase_test.h"
 
 #include "base/command_line.h"
+#include "base/prefs/pref_service.h"
+#include "chrome/browser/managed_mode/managed_mode_navigation_observer.h"
+#include "chrome/browser/profiles/profile.h"
+#include "chrome/browser/ui/browser.h"
+#include "chrome/browser/ui/tabs/tab_strip_model.h"
 #include "chrome/common/chrome_switches.h"
+#include "chrome/common/pref_names.h"
+#include "content/public/browser/web_contents.h"
 
 ManagedUserSetPassphraseTest::ManagedUserSetPassphraseTest() {
 }
 
 ManagedUserSetPassphraseTest::~ManagedUserSetPassphraseTest() {
 }
 
+void ManagedUserSetPassphraseTest::SetUpOnMainThread() {
+  WebUIBrowserTest::SetUpOnMainThread();
+  // Set up the ManagedModeNavigationObserver manually since the profile was
+  // not managed when the browser was created.
+  content::WebContents* web_contents =
+      browser()->tab_strip_model()->GetActiveWebContents();
+  ManagedModeNavigationObserver::CreateForWebContents(web_contents);
+
+  Profile* profile = browser()->profile();
+  profile->GetPrefs()->SetBoolean(prefs::kProfileIsManaged, true);
+}
+
 void ManagedUserSetPassphraseTest::SetUpCommandLine(CommandLine* command_line) {
   command_line->AppendSwitch(switches::kManaged);
   command_line->AppendSwitch(switches::kEnableManagedUsers);
 }