Move Singleton and related structs to namespace base

chrome/browser/ui/libgtk2ui/g_object_destructor_filo.h

 // Copyright (c) 2012 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_UI_LIBGTK2UI_G_OBJECT_DESTRUCTOR_FILO_H_
 #define CHROME_BROWSER_UI_LIBGTK2UI_G_OBJECT_DESTRUCTOR_FILO_H_
 
 #include <glib.h>
 #include <list>
 #include <map>
 
 #include "base/basictypes.h"
 
+namespace base {
 template <typename T> struct DefaultSingletonTraits;
+}
 
 typedef struct _GObject GObject;
 
 namespace libgtk2ui {
 
 // This class hooks calls to g_object_weak_ref()/unref() and executes them in
 // FILO order. This is important if there are several hooks to the single object
 // (set up at different levels of class hierarchy) and the lowest hook (set up
 // first) is deleting self - it must be called last (among hooks for the given
 // object). Unfortunately Glib does not provide this guarantee.
@@ skipping 40 matching lines @@
     }
     GObject* object;
     DestructorHook callback;
     void* context;
   };
   typedef std::list<Hook> HandlerList;
   typedef std::map<GObject*, HandlerList> HandlerMap;
 
   GObjectDestructorFILO();
   ~GObjectDestructorFILO();
-  friend struct DefaultSingletonTraits<GObjectDestructorFILO>;
+  friend struct base::DefaultSingletonTraits<GObjectDestructorFILO>;
 
   void WeakNotify(GObject* where_the_object_was);
   static void WeakNotifyThunk(gpointer data, GObject* where_the_object_was) {
     reinterpret_cast<GObjectDestructorFILO*>(data)->WeakNotify(
         where_the_object_was);
   }
 
   HandlerMap handler_map_;
 
   DISALLOW_COPY_AND_ASSIGN(GObjectDestructorFILO);
 };
 
 }  // namespace libgtk2ui
 
 #endif  // CHROME_BROWSER_UI_LIBGTK2UI_G_OBJECT_DESTRUCTOR_FILO_H_