Move Singleton and related structs to namespace base

extensions/common/extension_api.h

 // Copyright 2013 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 EXTENSIONS_COMMON_EXTENSION_API_H_
 #define EXTENSIONS_COMMON_EXTENSION_API_H_
 
 #include <map>
 #include <string>
 
@@ skipping 112 matching lines @@
   std::string GetAPINameFromFullName(const std::string& full_name,
                                      std::string* child_name);
 
   // Gets a feature from any dependency provider registered with ExtensionAPI.
   // Returns NULL if the feature could not be found.
   Feature* GetFeatureDependency(const std::string& dependency_name);
 
  private:
   FRIEND_TEST_ALL_PREFIXES(ExtensionAPITest, DefaultConfigurationFeatures);
   FRIEND_TEST_ALL_PREFIXES(ExtensionAPITest, TypesHaveNamespace);
-  friend struct DefaultSingletonTraits<ExtensionAPI>;
+  friend struct base::DefaultSingletonTraits<ExtensionAPI>;
 
   void InitDefaultConfiguration();
 
   bool default_configuration_initialized_;
 
   // Loads a schema.
   void LoadSchema(const std::string& name, const base::StringPiece& schema);
 
   // Map from each API that hasn't been loaded yet to the schema which defines
   // it. Note that there may be multiple APIs per schema.
   typedef std::map<std::string, int> UnloadedSchemaMap;
   UnloadedSchemaMap unloaded_schemas_;
 
   // Schemas for each namespace.
   typedef std::map<std::string, linked_ptr<const base::DictionaryValue> >
         SchemaMap;
   SchemaMap schemas_;
 
   // FeatureProviders used for resolving dependencies.
   typedef std::map<std::string, const FeatureProvider*> FeatureProviderMap;
   FeatureProviderMap dependency_providers_;
 
   DISALLOW_COPY_AND_ASSIGN(ExtensionAPI);
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_COMMON_EXTENSION_API_H_