Move Singleton and related structs to namespace base

ios/chrome/browser/content_settings/cookie_settings_factory.cc

 // Copyright 2015 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 "ios/chrome/browser/content_settings/cookie_settings_factory.h"
 
 #include "base/memory/singleton.h"
 #include "components/content_settings/core/browser/cookie_settings.h"
 #include "components/keyed_service/ios/browser_state_dependency_manager.h"
 #include "ios/chrome/browser/browser_state/browser_state_otr_helper.h"
 #include "ios/public/provider/chrome/browser/browser_state/chrome_browser_state.h"
 
 namespace {
 const char kDummyExtensionScheme[] = ":no-extension-scheme:";
 }
 
 namespace ios {
 
 // static
 scoped_refptr<content_settings::CookieSettings>
 CookieSettingsFactory::GetForBrowserState(
     ios::ChromeBrowserState* browser_state) {
   return static_cast<content_settings::CookieSettings*>(
       GetInstance()->GetServiceForBrowserState(browser_state, true).get());
 }
 
 // static
 CookieSettingsFactory* CookieSettingsFactory::GetInstance() {
-  return Singleton<CookieSettingsFactory>::get();
+  return base::Singleton<CookieSettingsFactory>::get();
 }
 
 CookieSettingsFactory::CookieSettingsFactory()
     : RefcountedBrowserStateKeyedServiceFactory(
           "CookieSettings",
           BrowserStateDependencyManager::GetInstance()) {
 }
 
 CookieSettingsFactory::~CookieSettingsFactory() {
 }
@@ skipping 14 matching lines @@
 CookieSettingsFactory::BuildServiceInstanceFor(
     web::BrowserState* context) const {
   ios::ChromeBrowserState* browser_state =
       ios::ChromeBrowserState::FromBrowserState(context);
   return new content_settings::CookieSettings(
       browser_state->GetHostContentSettingsMap(), browser_state->GetPrefs(),
       kDummyExtensionScheme);
 }
 
 }  // namespace ios