[Sync] Handle reassociation of tabs where the old tab is already mapped.

components/sync_sessions/sessions_sync_manager.cc

Index: components/sync_sessions/sessions_sync_manager.cc
diff --git a/components/sync_sessions/sessions_sync_manager.cc b/components/sync_sessions/sessions_sync_manager.cc
index f985b3db1e34608ee6d25fbcfa61ec780fb92c79..47351d79953bc71ccd4f0ba4731720f14a33dc85 100644
--- a/components/sync_sessions/sessions_sync_manager.cc
+++ b/components/sync_sessions/sessions_sync_manager.cc
@@ -864,9 +864,6 @@ bool SessionsSyncManager::InitFromSyncModel(
               rewritten_specifics.tab_node_id(), new_tab_id);
           UpdateTrackerWithSpecifics(rewritten_specifics,
                                      remote.GetModifiedTime());
-
-          session_tracker_.ReassociateLocalTab(
-              rewritten_specifics.tab_node_id(), new_tab_id);
         }
       }
     }