Move Singleton and related structs to namespace base

components/keyed_service/content/browser_context_dependency_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 COMPONENTS_KEYED_SERVICE_CONTENT_BROWSER_CONTEXT_DEPENDENCY_MANAGER_H_
 #define COMPONENTS_KEYED_SERVICE_CONTENT_BROWSER_CONTEXT_DEPENDENCY_MANAGER_H_
 
 #include "base/callback_forward.h"
 #include "base/callback_list.h"
 #include "components/keyed_service/core/dependency_manager.h"
 #include "components/keyed_service/core/keyed_service_export.h"
 
 class BrowserContextKeyedBaseFactory;
+
+namespace base {
 template <typename T>
 struct DefaultSingletonTraits;
+}  // namespace base
 
 namespace content {
 class BrowserContext;
 }
 
 namespace user_prefs {
 class PrefRegistrySyncable;
 }
 
 // A singleton that listens for context destruction notifications and
@@ skipping 47 matching lines @@
   // due to |context| aliasing a BrowserContext instance from a prior test
   // (i.e., 0xWhatever might be created, be destroyed, and then a new
   // BrowserContext object might be created at 0xWhatever).
   void MarkBrowserContextLiveForTesting(content::BrowserContext* context);
 #endif  // NDEBUG
 
   static BrowserContextDependencyManager* GetInstance();
 
  private:
   friend class BrowserContextDependencyManagerUnittests;
-  friend struct DefaultSingletonTraits<BrowserContextDependencyManager>;
+  friend struct base::DefaultSingletonTraits<BrowserContextDependencyManager>;
 
   // Helper function used by CreateBrowserContextServices[ForTest].
   void DoCreateBrowserContextServices(content::BrowserContext* context,
                                       bool is_testing_context);
 
   BrowserContextDependencyManager();
   ~BrowserContextDependencyManager() override;
 
 #ifndef NDEBUG
   // DependencyManager:
   void DumpContextDependencies(base::SupportsUserData* context) const final;
 #endif  // NDEBUG
 
   // A list of callbacks to call just before executing
   // CreateBrowserContextServices() or CreateBrowserContextServicesForTest().
   base::CallbackList<void(content::BrowserContext*)>
       will_create_browser_context_services_callbacks_;
 };
 
 #endif  // COMPONENTS_KEYED_SERVICE_CONTENT_BROWSER_CONTEXT_DEPENDENCY_MANAGER_H_