Move Singleton and related structs to namespace base

extensions/browser/app_window/app_window_geometry_cache.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 "extensions/browser/app_window/app_window_geometry_cache.h"
 
 #include "base/bind.h"
 #include "base/stl_util.h"
 #include "base/strings/string_number_conversions.h"
 #include "components/keyed_service/content/browser_context_dependency_manager.h"
@@ skipping 249 matching lines @@
 // static
 AppWindowGeometryCache* AppWindowGeometryCache::Factory::GetForContext(
     content::BrowserContext* context,
     bool create) {
   return static_cast<AppWindowGeometryCache*>(
       GetInstance()->GetServiceForBrowserContext(context, create));
 }
 
 AppWindowGeometryCache::Factory*
 AppWindowGeometryCache::Factory::GetInstance() {
-  return Singleton<AppWindowGeometryCache::Factory>::get();
+  return base::Singleton<AppWindowGeometryCache::Factory>::get();
 }
 
 AppWindowGeometryCache::Factory::Factory()
     : BrowserContextKeyedServiceFactory(
           "AppWindowGeometryCache",
           BrowserContextDependencyManager::GetInstance()) {
   DependsOn(ExtensionPrefsFactory::GetInstance());
 }
 
 AppWindowGeometryCache::Factory::~Factory() {}
@@ skipping 15 matching lines @@
 
 void AppWindowGeometryCache::AddObserver(Observer* observer) {
   observers_.AddObserver(observer);
 }
 
 void AppWindowGeometryCache::RemoveObserver(Observer* observer) {
   observers_.RemoveObserver(observer);
 }
 
 }  // namespace extensions