Move Singleton and related structs to namespace base

components/keyed_service/ios/browser_state_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_IOS_BROWSER_STATE_DEPENDENCY_MANAGER_H_
 #define COMPONENTS_KEYED_SERVICE_IOS_BROWSER_STATE_DEPENDENCY_MANAGER_H_
 
 #include "base/callback_forward.h"
 #include "base/callback_list.h"
 #include "base/macros.h"
 #include "components/keyed_service/core/dependency_manager.h"
 #include "components/keyed_service/core/keyed_service_export.h"
 
+namespace base {
 template <typename T>
 struct DefaultSingletonTraits;
+}  // namespace base
 
 namespace web {
 class BrowserState;
 }
 
 namespace user_prefs {
 class PrefRegistrySyncable;
 }
 
 // A singleton that listens for context destruction notifications and
@@ skipping 36 matching lines @@
 
   // Marks |context| as live (i.e., not stale). This method can be called as a
   // safeguard against |AssertBrowserStateWasntDestroyed()| checks going off
   // due to |context| aliasing a BrowserState instance from a prior test
   // (i.e., 0xWhatever might be created, be destroyed, and then a new
   // BrowserState object might be created at 0xWhatever).
   void MarkBrowserStateLiveForTesting(web::BrowserState* context);
 #endif  // NDEBUG
 
  private:
-  friend struct DefaultSingletonTraits<BrowserStateDependencyManager>;
+  friend struct base::DefaultSingletonTraits<BrowserStateDependencyManager>;
 
   BrowserStateDependencyManager();
   ~BrowserStateDependencyManager() override;
 
   // Helper function used by CreateBrowserStateServices[ForTest].
   void DoCreateBrowserStateServices(web::BrowserState* context,
                                     bool is_testing_context);
 
 #ifndef NDEBUG
   // DependencyManager:
   void DumpContextDependencies(base::SupportsUserData* context) const final;
 #endif  // NDEBUG
 
   DISALLOW_COPY_AND_ASSIGN(BrowserStateDependencyManager);
 };
 
 #endif  // COMPONENTS_KEYED_SERVICE_IOS_BROWSER_STATE_DEPENDENCY_MANAGER_H_