Move Singleton and related structs to namespace base

extensions/browser/api/device_permissions_manager.h

 // 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.
 
 #ifndef EXTENSIONS_DEVICE_PERMISSION_MANAGER_H_
 #define EXTENSIONS_DEVICE_PERMISSION_MANAGER_H_
 
 #include <map>
 #include <set>
 #include <vector>
 
 #include "base/gtest_prod_util.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/scoped_observer.h"
 #include "base/strings/string16.h"
 #include "base/threading/thread_checker.h"
 #include "components/keyed_service/content/browser_context_keyed_service_factory.h"
 #include "components/keyed_service/core/keyed_service.h"
 #include "device/hid/hid_service.h"
 #include "device/usb/usb_service.h"
 
+namespace base {
 template <typename T>
 struct DefaultSingletonTraits;
-
-namespace base {
 class Value;
 }
 
 namespace content {
 class BrowserContext;
 }
 
 namespace extensions {
 
 // Stores information about a device saved with access granted.
@@ skipping 165 matching lines @@
 };
 
 class DevicePermissionsManagerFactory
     : public BrowserContextKeyedServiceFactory {
  public:
   static DevicePermissionsManager* GetForBrowserContext(
       content::BrowserContext* context);
   static DevicePermissionsManagerFactory* GetInstance();
 
  private:
-  friend struct DefaultSingletonTraits<DevicePermissionsManagerFactory>;
+  friend struct base::DefaultSingletonTraits<DevicePermissionsManagerFactory>;
 
   DevicePermissionsManagerFactory();
   ~DevicePermissionsManagerFactory() override;
 
   // BrowserContextKeyedServiceFactory implementation
   KeyedService* BuildServiceInstanceFor(
       content::BrowserContext* context) const override;
   content::BrowserContext* GetBrowserContextToUse(
       content::BrowserContext* context) const override;
 
   DISALLOW_COPY_AND_ASSIGN(DevicePermissionsManagerFactory);
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_DEVICE_PERMISSION_MANAGER_H_