35     Segment *Prev;  member
119         DCHECK_NE(S->Prev, &SentinelSegment);
120         S = S->Prev;
222       DCHECK_EQ(Freelist->Prev, &SentinelSegment);  in NewSegment()
241         Freelist->Prev = &SentinelSegment;  in NewSegment()
244       FreeSegment->Prev = &SentinelSegment;  in NewSegment()
247       DCHECK_EQ(Freelist->Prev, &SentinelSegment);  in NewSegment()
269     DCHECK_EQ(S->Prev, &SentinelSegment);  in InitHeadAndTail()
275     DCHECK_EQ(Tail->Prev, &SentinelSegment);  in InitHeadAndTail()
285     DCHECK_EQ(S->Prev, &SentinelSegment);  in AppendNewSegment()
287     S->Prev = Tail;  in AppendNewSegment()
290     DCHECK_EQ(S, S->Prev->Next);  in AppendNewSegment()
556         auto SPT = Tail->Prev;  in trim()
558         Tail->Prev = &SentinelSegment;  in trim()
565         DCHECK_EQ(Freelist->Prev, &SentinelSegment);  in trim()
596         auto SPT = Tail->Prev;  in trim()
598         SFH->Prev = ST;  in trim()
600         ST->Prev = &SentinelSegment;  in trim()
607         DCHECK_EQ(Freelist->Prev, &SentinelSegment);  in trim()
608         DCHECK_EQ(Freelist->Next->Prev, Freelist);  in trim()
622         (Freelist != &SentinelSegment && Freelist->Prev == &SentinelSegment) ||  in trim()