container_type member alias for sorted-vector types

Summary: [Folly] container_type member alias for `sorted_vector_set` and `sorted_vector_map`, following the protocol from `std::queue`, `std::priority_queue`, and `std::stack` container adaptors.

Reviewed By: vitaut

Differential Revision: D15194108

fbshipit-source-id: 91332478c66779690f415d598b99274b8ee52df4

folly/sorted_vector_types.h

@@ -240,6 +240,7 @@ class sorted_vector_set : detail::growth_policy_wrapper<GrowthPolicy> {
   typedef Compare key_compare;
   typedef Compare value_compare;
   typedef Allocator allocator_type;
+  typedef Container container_type;
 
   typedef typename Container::pointer pointer;
   typedef typename Container::reference reference;
@@ -649,6 +650,7 @@ class sorted_vector_map : detail::growth_policy_wrapper<GrowthPolicy> {
   typedef typename Container::value_type value_type;
   typedef Compare key_compare;
   typedef Allocator allocator_type;
+  typedef Container container_type;
 
   struct value_compare : private Compare {
     bool operator()(const value_type& a, const value_type& b) const {