Move Singleton and related structs to namespace base

ui/views/accessibility/ax_aura_obj_cache.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 UI_VIEWS_ACCESSIBILITY_AX_AURA_OBJ_CACHE_H_
 #define UI_VIEWS_ACCESSIBILITY_AX_AURA_OBJ_CACHE_H_
 
 #include <map>
 #include <vector>
 
 #include "base/basictypes.h"
 #include "ui/views/views_export.h"
 
+namespace base {
 template <typename T> struct DefaultSingletonTraits;
+}
 
 namespace aura {
 class Window;
 }  // namespace aura
 
 namespace views {
 class AXAuraObjWrapper;
 class View;
 class Widget;
 
@@ skipping 31 matching lines @@
   // Remove a cached entry based on an id.
   void Remove(int32 id);
 
   // Get all top level windows this cache knows about.
   void GetTopLevelWindows(std::vector<AXAuraObjWrapper*>* children);
 
   // Indicates if this object's currently being destroyed.
   bool is_destroying() { return is_destroying_; }
 
  private:
-  friend struct DefaultSingletonTraits<AXAuraObjCache>;
+  friend struct base::DefaultSingletonTraits<AXAuraObjCache>;
 
   AXAuraObjCache();
   virtual ~AXAuraObjCache();
 
   template <typename AuraViewWrapper, typename AuraView>
       AXAuraObjWrapper* CreateInternal(
           AuraView* aura_view, std::map<AuraView*, int32>& aura_view_to_id_map);
 
   template<typename AuraView> int32 GetIDInternal(
       AuraView* aura_view, std::map<AuraView*, int32>& aura_view_to_id_map);
@@ skipping 10 matching lines @@
 
   // True immediately when entering this object's destructor.
   bool is_destroying_;
 
   DISALLOW_COPY_AND_ASSIGN(AXAuraObjCache);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_ACCESSIBILITY_AX_AURA_OBJ_CACHE_H_