Trim scoped_ptr.h down to just #include <memory>.

base/memory/scoped_ptr.h

Index: base/memory/scoped_ptr.h
diff --git a/base/memory/scoped_ptr.h b/base/memory/scoped_ptr.h
index 50a4e09cf834f64c9a0ec641251b72f8e9368aaf..63bb7bd3fd68e708b30f525f10c3e1b774c95643 100644
--- a/base/memory/scoped_ptr.h
+++ b/base/memory/scoped_ptr.h
@@ -90,10 +90,6 @@
 // This is an implementation designed to match the anticipated future TR2
 // implementation of the scoped_ptr class.
 
-// TODO(dcheng): Clean up these headers, but there are likely lots of existing
-// IWYU violations.
-#include <stdlib.h>
-
 #include <memory>
 
 template <typename T, typename D = std::default_delete<T>>