Allow for overriding functions in visualization (#3900)

src/ngraph/pass/visualize_tree.hpp

@@ -49,13 +49,13 @@ public:
     bool run_on_module(std::vector<std::shared_ptr<ngraph::Function>>&) override;
 
     void set_ops_to_details(const visualize_tree_ops_map_t& ops_map) { m_ops_to_details = ops_map; }
-private:
+protected:
     void add_node_arguments(std::shared_ptr<Node> node,
                             std::unordered_map<Node*, HeightMap>& height_maps,
                             size_t& fake_node_ctr);
     std::string add_attributes(std::shared_ptr<Node> node);
-    std::string get_attributes(std::shared_ptr<Node> node);
-    std::string get_node_name(std::shared_ptr<Node> node);
+    virtual std::string get_attributes(std::shared_ptr<Node> node);
+    virtual std::string get_node_name(std::shared_ptr<Node> node);
     void render() const;
 
     std::stringstream m_ss;