Move Singleton and related structs to namespace base

content/browser/renderer_host/media/media_capture_devices_impl.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 CONTENT_BROWSER_RENDERER_HOST_MEDIA_MEDIA_CAPTURE_DEVICES_IMPL_H_
 #define CONTENT_BROWSER_RENDERER_HOST_MEDIA_MEDIA_CAPTURE_DEVICES_IMPL_H_
 
 #include "base/memory/singleton.h"
 #include "content/public/browser/media_capture_devices.h"
 
 namespace content {
 
 class MediaCaptureDevicesImpl : public MediaCaptureDevices {
  public:
   static MediaCaptureDevicesImpl* GetInstance();
 
   // Overriden from MediaCaptureDevices
   const MediaStreamDevices& GetAudioCaptureDevices() override;
   const MediaStreamDevices& GetVideoCaptureDevices() override;
 
   // Called by MediaStreamManager to notify the change of media capture
   // devices, these 2 methods are called in IO thread.
   void OnAudioCaptureDevicesChanged(const MediaStreamDevices& devices);
   void OnVideoCaptureDevicesChanged(const MediaStreamDevices& devices);
 
  private:
-  friend struct DefaultSingletonTraits<MediaCaptureDevicesImpl>;
+  friend struct base::DefaultSingletonTraits<MediaCaptureDevicesImpl>;
   MediaCaptureDevicesImpl();
   ~MediaCaptureDevicesImpl() override;
 
   void UpdateAudioDevicesOnUIThread(const content::MediaStreamDevices& devices);
   void UpdateVideoDevicesOnUIThread(const content::MediaStreamDevices& devices);
 
   // Flag to indicate if device enumeration has been done/doing.
   // Only accessed on UI thread.
   bool devices_enumerated_;
 
   // A list of cached audio capture devices.
   MediaStreamDevices audio_devices_;
 
   // A list of cached video capture devices.
   MediaStreamDevices video_devices_;
 
   DISALLOW_COPY_AND_ASSIGN(MediaCaptureDevicesImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_MEDIA_MEDIA_CAPTURE_DEVICES_IMPL_H_