Move Singleton and related structs to namespace base

ui/views/win/windows_session_change_observer.cc

 // Copyright 2015 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 "ui/views/win/windows_session_change_observer.h"
 
 #include <wtsapi32.h>
 #pragma comment(lib, "wtsapi32.lib")
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/callback.h"
 #include "base/location.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/singleton.h"
 #include "base/observer_list.h"
 #include "base/task_runner.h"
 #include "ui/gfx/win/singleton_hwnd.h"
 #include "ui/gfx/win/singleton_hwnd_observer.h"
 #include "ui/views/views_delegate.h"
 
 namespace views {
 
 class WindowsSessionChangeObserver::WtsRegistrationNotificationManager {
  public:
   static WtsRegistrationNotificationManager* GetInstance() {
-    return Singleton<WtsRegistrationNotificationManager>::get();
+    return base::Singleton<WtsRegistrationNotificationManager>::get();
   }
 
   WtsRegistrationNotificationManager() {
     AddSingletonHwndObserver();
   }
 
   ~WtsRegistrationNotificationManager() {
     RemoveSingletonHwndObserver();
   }
 
   void AddObserver(WindowsSessionChangeObserver* observer) {
     DCHECK(singleton_hwnd_observer_);
     observer_list_.AddObserver(observer);
   }
 
   void RemoveObserver(WindowsSessionChangeObserver* observer) {
     observer_list_.RemoveObserver(observer);
   }
 
  private:
-  friend struct DefaultSingletonTraits<WtsRegistrationNotificationManager>;
+  friend struct base::DefaultSingletonTraits<
+      WtsRegistrationNotificationManager>;
 
   void OnWndProc(HWND hwnd, UINT message, WPARAM wparam, LPARAM lparam) {
     switch (message) {
       case WM_WTSSESSION_CHANGE:
         FOR_EACH_OBSERVER(WindowsSessionChangeObserver,
                           observer_list_,
                           OnSessionChange(wparam));
         break;
       case WM_DESTROY:
         RemoveSingletonHwndObserver();
@@ skipping 61 matching lines @@
 }
 
 void WindowsSessionChangeObserver::ClearCallback() {
   if (!callback_.is_null()) {
     callback_.Reset();
     WtsRegistrationNotificationManager::GetInstance()->RemoveObserver(this);
   }
 }
 
 }  // namespace views