OP_OPEN_PREV      125 net/disk_cache/blockfile/in_flight_backend_io.cc   operation_ = OP_OPEN_PREV;
OP_OPEN_PREV      221 net/disk_cache/blockfile/in_flight_backend_io.cc           operation_ == OP_OPEN_NEXT || operation_ == OP_OPEN_PREV);
OP_OPEN_PREV      255 net/disk_cache/blockfile/in_flight_backend_io.cc     case OP_OPEN_PREV: