Move Singleton and related structs to namespace base

courgette/courgette_config.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 COURGETTE_COURGETTE_CONFIG_H_
 #define COURGETTE_COURGETTE_CONFIG_H_
 
 #include "base/macros.h"
 #include "base/memory/singleton.h"
 
@@ skipping 13 matching lines @@
 
   bool is_experimental() const { return is_experimental_; }
 
   uint32 ensemble_version() const;
 
  private:
   bool is_experimental_;
 
   CourgetteConfig();
 
-  friend struct DefaultSingletonTraits<CourgetteConfig>;
+  friend struct base::DefaultSingletonTraits<CourgetteConfig>;
 };
 
 }  // namespace courgette
 
 #endif  // COURGETTE_COURGETTE_CONFIG_H_