Move Singleton and related structs to namespace base

content/browser/tracing/power_tracing_agent.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 CONTENT_BROWSER_TRACING_POWER_TRACING_AGENT_H_
 #define CONTENT_BROWSER_TRACING_POWER_TRACING_AGENT_H_
 
 #include "base/memory/ref_counted_memory.h"
 #include "base/threading/thread.h"
 
+namespace base {
 template <typename Type>
 struct DefaultSingletonTraits;
+}  // namespace base
 
 namespace content {
 
 class BattorPowerTraceProvider;
 
 class PowerTracingAgent {
  public:
   typedef base::Callback<void(const scoped_refptr<base::RefCountedString>&)>
       OutputCallback;
 
   bool StartTracing();
   void StopTracing(const OutputCallback& callback);
 
   // Retrieve the singleton instance.
   static PowerTracingAgent* GetInstance();
 
  private:
   // This allows constructor and destructor to be private and usable only
   // by the Singleton class.
-  friend struct DefaultSingletonTraits<PowerTracingAgent>;
+  friend struct base::DefaultSingletonTraits<PowerTracingAgent>;
 
   // Constructor.
   PowerTracingAgent();
   virtual ~PowerTracingAgent();
 
   void OnStopTracingDone(const OutputCallback& callback,
                          const scoped_refptr<base::RefCountedString>& result);
 
   void FlushOnThread(const OutputCallback& callback);
 
   scoped_ptr<BattorPowerTraceProvider> battor_trace_provider_;
   bool is_tracing_;
 
   DISALLOW_COPY_AND_ASSIGN(PowerTracingAgent);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_TRACING_POWER_TRACING_AGENT_H_