Move Singleton and related structs to namespace base

chrome/browser/extensions/api/desktop_capture/desktop_capture_base.h

 // 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.
 
 #ifndef CHROME_BROWSER_EXTENSIONS_API_DESKTOP_CAPTURE_DESKTOP_CAPTURE_BASE_H_
 #define CHROME_BROWSER_EXTENSIONS_API_DESKTOP_CAPTURE_DESKTOP_CAPTURE_BASE_H_
 
 #include <map>
 
 #include "base/memory/singleton.h"
@@ skipping 79 matching lines @@
 
   static DesktopCaptureRequestsRegistry* GetInstance();
 
   void AddRequest(int process_id,
                   int request_id,
                   DesktopCaptureChooseDesktopMediaFunctionBase* handler);
   void RemoveRequest(int process_id, int request_id);
   void CancelRequest(int process_id, int request_id);
 
  private:
-  friend struct DefaultSingletonTraits<DesktopCaptureRequestsRegistry>;
+  friend struct base::DefaultSingletonTraits<DesktopCaptureRequestsRegistry>;
 
   struct RequestId {
     RequestId(int process_id, int request_id);
 
     // Need to use RequestId as a key in std::map<>.
     bool operator<(const RequestId& other) const;
 
     int process_id;
     int request_id;
   };
 
   using RequestsMap =
       std::map<RequestId, DesktopCaptureChooseDesktopMediaFunctionBase*>;
 
   RequestsMap requests_;
 
   DISALLOW_COPY_AND_ASSIGN(DesktopCaptureRequestsRegistry);
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_API_DESKTOP_CAPTURE_DESKTOP_CAPTURE_BASE_H_