dcsctp: Remove dead code

This was only used for handover state, and not updated at all after
https://webrtc-review.googlesource.com/c/src/+/322623.

Bug: None
Change-Id: I5005902486d1fae76badd9f196e0e3525fe573de
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/349163
Commit-Queue: Victor Boivie <boivie@webrtc.org>
Reviewed-by: Florent Castelli <orphis@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#42175}
diff --git a/net/dcsctp/rx/reassembly_queue.cc b/net/dcsctp/rx/reassembly_queue.cc
index ac1cdd8..6f22806 100644
--- a/net/dcsctp/rx/reassembly_queue.cc
+++ b/net/dcsctp/rx/reassembly_queue.cc
@@ -27,6 +27,7 @@
 #include "net/dcsctp/packet/data.h"
 #include "net/dcsctp/packet/parameter/outgoing_ssn_reset_request_parameter.h"
 #include "net/dcsctp/packet/parameter/reconfiguration_response_parameter.h"
+#include "net/dcsctp/public/dcsctp_handover_state.h"
 #include "net/dcsctp/public/dcsctp_message.h"
 #include "net/dcsctp/public/types.h"
 #include "net/dcsctp/rx/interleaved_reassembly_streams.h"
@@ -56,7 +57,6 @@
     : log_prefix_(log_prefix),
       max_size_bytes_(max_size_bytes),
       watermark_bytes_(max_size_bytes * kHighWatermarkLimit),
-      last_completed_reset_req_seq_nbr_(ReconfigRequestSN(0)),
       streams_(CreateStreams(
           log_prefix_,
           [this](rtc::ArrayView<const UnwrappedTSN> tsns,
@@ -221,17 +221,10 @@
 }
 
 void ReassemblyQueue::AddHandoverState(DcSctpSocketHandoverState& state) {
-  state.rx.last_completed_deferred_reset_req_sn =
-      last_completed_reset_req_seq_nbr_.value();
   streams_->AddHandoverState(state);
 }
 
 void ReassemblyQueue::RestoreFromState(const DcSctpSocketHandoverState& state) {
-  // Validate that the component is in pristine state.
-  RTC_DCHECK(last_completed_reset_req_seq_nbr_ == ReconfigRequestSN(0));
-
-  last_completed_reset_req_seq_nbr_ =
-      ReconfigRequestSN(state.rx.last_completed_deferred_reset_req_sn);
   streams_->RestoreFromState(state);
 }
 }  // namespace dcsctp
diff --git a/net/dcsctp/rx/reassembly_queue.h b/net/dcsctp/rx/reassembly_queue.h
index dc28be4..9e0b6e2 100644
--- a/net/dcsctp/rx/reassembly_queue.h
+++ b/net/dcsctp/rx/reassembly_queue.h
@@ -28,7 +28,6 @@
 #include "net/dcsctp/packet/data.h"
 #include "net/dcsctp/packet/parameter/outgoing_ssn_reset_request_parameter.h"
 #include "net/dcsctp/packet/parameter/reconfiguration_response_parameter.h"
-#include "net/dcsctp/public/dcsctp_handover_state.h"
 #include "net/dcsctp/public/dcsctp_message.h"
 #include "net/dcsctp/rx/reassembly_streams.h"
 #include "rtc_base/containers/flat_set.h"
@@ -154,10 +153,6 @@
   // If present, "deferred reset processing" mode is active.
   absl::optional<DeferredResetStreams> deferred_reset_streams_;
 
-  // Contains the last request sequence number of the
-  // OutgoingSSNResetRequestParameter that was performed.
-  ReconfigRequestSN last_completed_reset_req_seq_nbr_;
-
   // The number of "payload bytes" that are in this queue, in total.
   size_t queued_bytes_ = 0;