C++ overload resolution in bindings layer

Source/bindings/dart/scripts/templates/interface_cpp.template

 {% extends 'interface_base_cpp.template' %}
 
 
 {##############################################################################}
 {# Mangled Blink name used by resolver to map to static function.             #}
 {##############################################################################}
 {% macro resolver_callback_string(class_name, name, argument) -%}
 {% set name = '__' + name + '___' -%}
 {% if argument -%}
 {{class_name}}_{{name}}Callback_{{argument}}
@@ skipping 119 matching lines @@
 {% endblock %}
 
 {##############################################################################}
 {% block to_dart_no_inline %}
 template<>
 Dart_Handle toDartNoInline({{cpp_class}}* impl, DartDOMData* domData)
 {
     return {{dart_class}}::toDart(impl);
 }
 {% endblock %}
+
+{% from 'methods_cpp.template' import static_method_name with context %}
+
+{##############################################################################}
+{% block overloaded_constructor %}
+{% if constructor_overloads %}
+static void constructorCallbackDispatcher(Dart_NativeArguments args)
+{
+    Dart_Handle exception = 0;
+    const int argOffset = 0;
+    int argCount = Dart_GetNativeArgumentCount(args) + argOffset;
+    {# 2. Initialize argcount to be min(maxarg, n). #}
+    switch (std::min({{constructor_overloads.maxarg}}, argCount)) {
+    {# 3. Remove from S all entries whose type list is not of length argcount. #}
+    {% for length, tests_constructors in constructor_overloads.length_tests_methods %}
+    case {{length}}:
+        {# Then resolve by testing argument #}
+        {% for test, constructor in tests_constructors %}
+        {# 10. If i = d, then: #}
+        if ({{test}}) {
+          {% if constructor.is_custom %}
+            {{static_method_name(constructor.name)}}(args);
+          {% else %}
+            {{static_method_name(constructor.name, constructor.overload_index)}}(args);
+          {% endif %}
+            return;
+        }
+        {% endfor %}
+        break;
+    {% endfor %}
+    default:
+        {# Invalid arity, throw error #}
+        {# Report full list of valid arities if gaps and above minimum #}
+        {% if constructor_overloads.valid_arities %}
+        if (argCount >= {{overloads.minarg}}) {
+            const String message = "Wrong arity, expected one of {{constructor_overloads.valid_arities}}";
+            exception = DartUtilities::coreArgumentErrorException(message);
+            goto fail;
+        }
+        {% endif %}
+        {# Otherwise just report "not enough arguments" #}
+        {
+            const String message = "Not enough arguments (at least {{constructor_overloads.minarg}} required)";
+            exception = DartUtilities::coreArgumentErrorException(message);
+            goto fail;
+        }
+        return;
+    }
+    {# No match, throw error #}
+    {
+        const String message = "No matching constructor signature.";
+        exception = DartUtilities::coreArgumentErrorException(message);
+        goto fail;
+    }
+    return;
+fail:
+    Dart_ThrowException(exception);
+    ASSERT_NOT_REACHED();
+}
+{% endif %}
+{% endblock %}
+
+
+{##############################################################################}