42   typedef std::map<K, PersistentContainerValue> Impl;  typedef
43   typedef typename Impl::iterator Iterator;
45   static bool Empty(Impl* impl) { return impl->empty(); }  in Empty()
46   static size_t Size(Impl* impl) { return impl->size(); }  in Size()
47   static void Swap(Impl& a, Impl& b) { std::swap(a, b); }  // NOLINT  in Swap()
48   static Iterator Begin(Impl* impl) { return impl->begin(); }  in Begin()
49   static Iterator End(Impl* impl) { return impl->end(); }  in End()
52   static PersistentContainerValue Set(Impl* impl, K key,  in Set()
62   static PersistentContainerValue Get(Impl* impl, K key) {  in Get()
67   static PersistentContainerValue Remove(Impl* impl, K key) {  in Remove()
235       typename Traits::Impl impl;
306   typename Traits::Impl* impl() { return &impl_; }
358   typename Traits::Impl impl_;
539   typedef std::vector<PersistentContainerValue> Impl;
541   static void Append(Impl* impl, PersistentContainerValue value) {
544   static bool IsEmpty(const Impl* impl) {
547   static size_t Size(const Impl* impl) {
550   static PersistentContainerValue Get(const Impl* impl, size_t i) {
553   static void ReserveCapacity(Impl* impl, size_t capacity) {
556   static void Clear(Impl* impl) {
649   typename Traits::Impl impl_;