Add a convenience typedef LazyInstance<T>::Leaky to avoid repeating T.

base/tracked_objects.h

Index: base/tracked_objects.h
diff --git a/base/tracked_objects.h b/base/tracked_objects.h
index a088ee201bac95b754e36dff68bfe17f219134e4..785712ff800e61d81139fc939f21a66e40ca0e0f 100644
--- a/base/tracked_objects.h
+++ b/base/tracked_objects.h
@@ -575,8 +575,7 @@ class BASE_EXPORT ThreadData {
   // unregistered_thread_data_pool_.  This lock is leaked at shutdown.
   // The lock is very infrequently used, so we can afford to just make a lazy
   // instance and be safe.
-  static base::LazyInstance<base::Lock,
-      base::LeakyLazyInstanceTraits<base::Lock> > list_lock_;
+  static base::LazyInstance<base::Lock>::Leaky list_lock_;
 
   // We set status_ to SHUTDOWN when we shut down the tracking service.
   static Status status_;