Make it possible to inherit from any constructable host object

sky/engine/bindings/scripts/templates/methods_cpp.template

 {##############################################################################}
 {# FIXME: We should return a rejected Promise if an error occurs in this
 function when ALL methods in this overload return Promise. In order to do so,
 we must ensure either ALL or NO methods in this overload return Promise #}
 {% macro overload_resolution_method(method) %}
 {% set overloads = method.overloads %}
 {% if method.is_static %}
   {% set offset = 0 %}
 {% else %}
   {% set offset = 1 %}
@@ skipping 317 matching lines @@
             exception = ToDart("Failed to fetch domWindow");
             goto fail;
         }
         Document& document = *domWindow->document();
 {% endif %}
         int argCount /* FIXME(vsm): Remove this. */ ALLOW_UNUSED = Dart_GetNativeArgumentCount(args);
 {% if constructor.has_exception_state %}
         ExceptionState es;
 {% endif %}
         {{generate_arguments(constructor) | indent(8)}}
-        {{callback_return(constructor, constructor.dart_set_return_value, constructor.cpp_value) | indent(8)}}
+        {{constructor.cpp_value}}->AssociateWithDartWrapper(args);
 {% if constructor.has_exception_state %}
         if (es.had_exception()) {
             exception = es.GetDartException(args, {{constructor.auto_scope}});
             goto fail;
         }
 
 {% endif %}
         return;
     }
 
@@ skipping 12 matching lines @@
 {
     Dart_SetReturnValue(args, Dart_Null());
 }
 {% endmacro %}
 
 ,
 {##############################################################################}
 {% macro generate_resolver_constructor(dart_class, class_name, constructor) %}
 {% for native_entry in constructor.native_entries %}
 {% set resolver_string = native_entry.resolver_string %}
+{% set args_one_based = constructor.number_of_arguments + 1 %}
+{% set args_required_one_based = constructor.number_of_required_arguments + 1 %}
 {% if constructor.overload_index %}
   {% set constructor_name = static_method_name(constructor.name) + "Dispatcher" %}
 {% else %}
   {% set constructor_name = static_method_name(constructor.name) %}
 {% endif %}
 {% if has_custom_constructor %}
 if (name == "{{resolver_string}}") {
 {% elif constructor.number_of_arguments == constructor.number_of_required_arguments %}
-if (argumentCount == {{constructor.number_of_arguments}} && name == "{{resolver_string}}") {
+if (argumentCount == {{args_one_based}} && name == "{{resolver_string}}") {
 {% else %}
-if (argumentCount >= {{constructor.number_of_required_arguments}} && argumentCount <= {{constructor.number_of_arguments}} && name == "{{resolver_string}}") {
+if (argumentCount >= {{args_required_one_based}} && argumentCount <= {{args_one_based}} && name == "{{resolver_string}}") {
 {% endif %}
     *autoSetupScope = {{constructor.auto_scope}};
     return {{dart_class}}Internal::{{constructor_name}};
 }
 {% endfor %}
 {% endmacro %}
 
 {##############################################################################}
 {% macro generate_resolver_event_constructor(dart_class, class_name) %}
 {% set resolver_string = interface_name + "_constructorCallback" %}
 if (argumentCount == 2 && name == "{{resolver_string}}") {
     *autoSetupScope = 1;
     return {{dart_class}}Internal::eventConstructorCallback;
 }
 {% endmacro %}
 
 {##############################################################################}
 {% macro generate_symbolizer_constructor(dart_class, class_name, constructor) %}
 {% for native_entry in constructor.native_entries %}
 {% set resolver_string = native_entry.resolver_string %}
 if (native_function == {{dart_class}}Internal::{{static_method_name(constructor.name, constructor.overload_index)}}) {
   return reinterpret_cast<const uint8_t*>("{{resolver_string}}");
 }
 {% endfor %}
 {% endmacro %}