[Sync] ModelTypeWorker should delete tracker for entity deleted on the server

components/sync/engine_impl/model_type_worker.cc

Index: components/sync/engine_impl/model_type_worker.cc
diff --git a/components/sync/engine_impl/model_type_worker.cc b/components/sync/engine_impl/model_type_worker.cc
index de5b19d8e4bcc4e4b7ee2549dd92684c7bd21b98..32282a9cbd0557b3360152c32cf3a74dad677377 100644
--- a/components/sync/engine_impl/model_type_worker.cc
+++ b/components/sync/engine_impl/model_type_worker.cc
@@ -304,7 +304,15 @@ void ModelTypeWorker::OnCommitResponse(CommitResponseDataList* response_list) {
       continue;
     }
 
+    // Remember if entity was deleted. After ReceiveCommitResponse this flag
+    // will not be available.
+    bool is_tombstone = entity->IsTombstone();
+
     entity->ReceiveCommitResponse(&response);
+
+    if (is_tombstone) {
+      entities_.erase(response.client_tag_hash);
+    }
   }
 
   // Send the responses back to the model thread. It needs to know which