Move some files in base to base/memory.

base/memory/singleton.h

Index: base/memory/singleton.h
diff --git a/base/singleton.h b/base/memory/singleton.h
similarity index 98%
rename from base/singleton.h
rename to base/memory/singleton.h
index 0fe5e27825f68745adf027e64693177d28d7023e..f34286b52aca764a8d9f1b98ef4317e0c70b8999 100644
--- a/base/singleton.h
+++ b/base/memory/singleton.h
@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef BASE_SINGLETON_H_
-#define BASE_SINGLETON_H_
+#ifndef BASE_MEMORY_SINGLETON_H_
+#define BASE_MEMORY_SINGLETON_H_
 #pragma once
 
 #include "base/at_exit.h"
@@ -126,7 +126,7 @@ template <typename Type> base::subtle::Atomic32
 // Example usage:
 //
 // In your header:
-//   #include "base/singleton.h"
+//   #include "base/memory/singleton.h"
 //   class FooClass {
 //    public:
 //     static FooClass* GetInstance();  <-- See comment below on this.
@@ -268,4 +268,4 @@ template <typename Type, typename Traits, typename DifferentiatingType>
 base::subtle::AtomicWord Singleton<Type, Traits, DifferentiatingType>::
     instance_ = 0;
 
-#endif  // BASE_SINGLETON_H_
+#endif  // BASE_MEMORY_SINGLETON_H_