22   explicit LRUElement() : next_(nullptr), prev_(nullptr), refs_(0) {}  in LRUElement()
27   T* prev_;  member
48     assert(!t->prev_);  in Push()
53     assert(!head_ || !head_->prev_);  in Push()
58       head_->prev_ = t;  in Push()
79     assert(!head_->prev_);  in Pop()
119     assert(t->prev_ || head_ == t);  in UnlinkImpl()
122     if (t->prev_) {  in UnlinkImpl()
123       t->prev_->next_ = t->next_;  in UnlinkImpl()
126       t->next_->prev_ = t->prev_;  in UnlinkImpl()
130       tail_ = tail_->prev_;  in UnlinkImpl()
136     t->next_ = t->prev_ = nullptr;  in UnlinkImpl()
148     assert(!t->prev_);  in PushBackImpl()
153     assert(!head_ || !head_->prev_);  in PushBackImpl()
156     t->prev_ = tail_;  in PushBackImpl()