Move Singleton and related structs to namespace base

crypto/mac_security_services_lock.cc

Index: crypto/mac_security_services_lock.cc
diff --git a/crypto/mac_security_services_lock.cc b/crypto/mac_security_services_lock.cc
index c0b8712089e9c76003ed2b47db7f7ba42fb1c052..af66918f3cae106ed89a411dedcf7b518134d692 100644
--- a/crypto/mac_security_services_lock.cc
+++ b/crypto/mac_security_services_lock.cc
@@ -14,14 +14,15 @@ namespace {
 class SecurityServicesSingleton {
  public:
   static SecurityServicesSingleton* GetInstance() {
-    return Singleton<SecurityServicesSingleton,
-                     LeakySingletonTraits<SecurityServicesSingleton> >::get();
+    return base::Singleton<
+        SecurityServicesSingleton,
+        base::LeakySingletonTraits<SecurityServicesSingleton>>::get();
   }
 
   base::Lock& lock() { return lock_; }
 
  private:
-  friend struct DefaultSingletonTraits<SecurityServicesSingleton>;
+  friend struct base::DefaultSingletonTraits<SecurityServicesSingleton>;
 
   SecurityServicesSingleton() {}
   ~SecurityServicesSingleton() {}