Move Singleton and related structs to namespace base

components/tracing/trace_config_file.h

 // Copyright (c) 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 COMPONENTS_TRACING_TRACE_CONFIG_FILE_H_
 #define COMPONENTS_TRACING_TRACE_CONFIG_FILE_H_
 
 #include "base/files/file_path.h"
 #include "base/macros.h"
 #include "base/trace_event/trace_config.h"
 #include "components/tracing/tracing_export.h"
 
+namespace base {
 template <typename Type> struct DefaultSingletonTraits;
+}  // namespace base
 
 namespace tracing {
 
 // TraceConfigFile is a singleton that contains the configurations of tracing.
 // One can create a trace config file and use it to configure startup and/or
 // shutdown tracing.
 //
 // The trace config file should be JSON formated. One example is:
 //   {
 //     "trace_config": {
@@ skipping 44 matching lines @@
   bool IsEnabled() const;
   base::trace_event::TraceConfig GetTraceConfig() const;
   int GetStartupDuration() const;
 #if !defined(OS_ANDROID)
   base::FilePath GetResultFile() const;
 #endif
 
  private:
   // This allows constructor and destructor to be private and usable only
   // by the Singleton class.
-  friend struct DefaultSingletonTraits<TraceConfigFile>;
+  friend struct base::DefaultSingletonTraits<TraceConfigFile>;
   TraceConfigFile();
   ~TraceConfigFile();
 
   bool ParseTraceConfigFileContent(std::string content);
 
   bool is_enabled_;
   base::trace_event::TraceConfig trace_config_;
   int startup_duration_;
   base::FilePath result_file_;
 
   DISALLOW_COPY_AND_ASSIGN(TraceConfigFile);
 };
 
 }  // namespace tracing
 
 #endif  // COMPONENTS_TRACING_TRACE_CONFIG_FILE_H_