[sync] Remove unused variable in SyncerProtoUtil::PostAndProcessHeaders

Fixed: 1413954
Change-Id: Ia10ae3e092f9363a97c3f3b7140610ccd2a300de
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4246648
Reviewed-by: Mikel Astiz <mastiz@chromium.org>
Commit-Queue: Ankush Singh <ankushkush@google.com>
Cr-Commit-Position: refs/heads/main@{#1105554}
diff --git a/components/sync/engine/syncer_proto_util.cc b/components/sync/engine/syncer_proto_util.cc
index ab71e75..31aac4d 100644
--- a/components/sync/engine/syncer_proto_util.cc
+++ b/components/sync/engine/syncer_proto_util.cc
@@ -273,8 +273,6 @@
                             msg.message_contents(),
                             ClientToServerMessage::Contents_MAX + 1);
 
-  std::map<int, std::string> progress_marker_token_per_data_type;
-
   if (msg.has_get_updates()) {
     UMA_HISTOGRAM_ENUMERATION("Sync.PostedGetUpdatesOrigin",
                               msg.get_updates().get_updates_origin(),
@@ -282,8 +280,6 @@
 
     for (const sync_pb::DataTypeProgressMarker& progress_marker :
          msg.get_updates().from_progress_marker()) {
-      progress_marker_token_per_data_type[progress_marker.data_type_id()] =
-          progress_marker.token();
       UMA_HISTOGRAM_ENUMERATION(
           "Sync.PostedDataTypeGetUpdatesRequest",
           ModelTypeHistogramValue(GetModelTypeFromSpecificsFieldNumber(