Move Singleton and related structs to namespace base

components/keyed_service/ios/browser_state_dependency_manager.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/keyed_service/ios/browser_state_dependency_manager.h"
 
 #include "base/memory/singleton.h"
 #include "base/trace_event/trace_event.h"
 #include "ios/web/public/browser_state.h"
 
 // static
 BrowserStateDependencyManager* BrowserStateDependencyManager::GetInstance() {
-  return Singleton<BrowserStateDependencyManager>::get();
+  return base::Singleton<BrowserStateDependencyManager>::get();
 }
 
 void BrowserStateDependencyManager::RegisterBrowserStatePrefsForServices(
     web::BrowserState* context,
     user_prefs::PrefRegistrySyncable* pref_registry) {
   RegisterPrefsForServices(context, pref_registry);
 }
 
 void BrowserStateDependencyManager::CreateBrowserStateServices(
     web::BrowserState* context) {
@@ skipping 34 matching lines @@
   TRACE_EVENT0("browser",
                "BrowserStateDependencyManager::DoCreateBrowserStateServices")
   DependencyManager::CreateContextServices(context, is_testing_context);
 }
 
 #ifndef NDEBUG
 void BrowserStateDependencyManager::DumpContextDependencies(
     base::SupportsUserData* context) const {
 }
 #endif  // NDEBUG