Introduce incognito preference settings.

chrome/browser/dom_ui/new_tab_ui_uitest.cc

 // Copyright (c) 2010 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/test/ui/ui_test.h"
 
 #include "chrome/app/chrome_command_ids.h"
 #include "chrome/browser/dom_ui/new_tab_ui.h"
 #include "chrome/browser/prefs/pref_value_store.h"
 #include "chrome/browser/sync/signin_manager.h"
@@ skipping 113 matching lines @@
   ASSERT_TRUE(tab->ExecuteAndExtractInt(L"",
       L"window.domAutomationController.send("
       L"document.getElementsByClassName('thumbnail-container').length)",
       &thumbnails_count));
   EXPECT_GT(thumbnails_count, 0);
 }
 
 // Flaky on XP bots: http://crbug.com/51726
 TEST_F(NewTabUITest, FLAKY_UpdateUserPrefsVersion) {
   // PrefService with JSON user-pref file only, no enforced or advised prefs.
-  scoped_ptr<PrefService> prefs(new TestingPrefService);
+  scoped_ptr<PrefService> prefs(TestingPrefService::CreateTestingPrefService());
 
   // Does the migration
   NewTabUI::RegisterUserPrefs(prefs.get());
 
   ASSERT_EQ(NewTabUI::current_pref_version(),
             prefs->GetInteger(prefs::kNTPPrefVersion));
 
   // Reset the version
   prefs->ClearPref(prefs::kNTPPrefVersion);
   ASSERT_EQ(0, prefs->GetInteger(prefs::kNTPPrefVersion));
 
   bool migrated = NewTabUI::UpdateUserPrefsVersion(prefs.get());
   ASSERT_TRUE(migrated);
   ASSERT_EQ(NewTabUI::current_pref_version(),
             prefs->GetInteger(prefs::kNTPPrefVersion));
 
   migrated = NewTabUI::UpdateUserPrefsVersion(prefs.get());
   ASSERT_FALSE(migrated);
 }