Move Singleton and related structs to namespace base

components/sessions/ios/ios_serialized_navigation_driver.cc

 // Copyright 2014 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 "components/sessions/ios/ios_serialized_navigation_driver.h"
 
 #include "base/memory/singleton.h"
 #include "components/sessions/serialized_navigation_entry.h"
 #include "ios/web/public/referrer.h"
 
 namespace sessions {
 
 namespace {
 const int kObsoleteReferrerPolicyAlways = 0;
 const int kObsoleteReferrerPolicyDefault = 1;
 const int kObsoleteReferrerPolicyNever = 2;
 const int kObsoleteReferrerPolicyOrigin = 3;
 }  // namespace
 
 // static
 SerializedNavigationDriver* SerializedNavigationDriver::Get() {
   return IOSSerializedNavigationDriver::GetInstance();
 }
 
 // static
 IOSSerializedNavigationDriver*
 IOSSerializedNavigationDriver::GetInstance() {
-  return Singleton<IOSSerializedNavigationDriver,
-      LeakySingletonTraits<IOSSerializedNavigationDriver>>::get();
+  return base::Singleton<
+      IOSSerializedNavigationDriver,
+      base::LeakySingletonTraits<IOSSerializedNavigationDriver>>::get();
 }
 
 IOSSerializedNavigationDriver::IOSSerializedNavigationDriver() {
 }
 
 IOSSerializedNavigationDriver::~IOSSerializedNavigationDriver() {
 }
 
 int IOSSerializedNavigationDriver::GetDefaultReferrerPolicy() const {
   return web::ReferrerPolicyDefault;
@@ skipping 89 matching lines @@
     navigation->referrer_policy_ = GetDefaultReferrerPolicy();
   }
 }
 
 std::string IOSSerializedNavigationDriver::StripReferrerFromPageState(
       const std::string& page_state) const {
   return std::string();
 }
 
 }  // namespace sessions