IDL: Support runtime enabled overloads affecting Function.length

Source/bindings/templates/interface_base.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // This file has been auto-generated by {{code_generator}}. DO NOT MODIFY!
 
 #include "config.h"
 {% filter conditional(conditional_string) %}
 #include "{{v8_class_or_partial}}.h"
 
@@ skipping 122 matching lines @@
     {{cpp_class}}* impl = {{v8_class}}::toImpl(host);
     return BindingSecurity::shouldAllowAccessToFrame(v8::Isolate::GetCurrent(), impl->frame(), DoNotReportSecurityError);
 }
 
 {% endif %}
 {% endblock %}
 {##############################################################################}
 {# Methods #}
 {% from 'methods.cpp' import generate_method, overload_resolution_method,
        method_callback, origin_safe_method_getter, generate_constructor,
-       method_implemented_in_private_script
+       method_implemented_in_private_script, runtime_determined_length_method
        with context %}
 {% for method in methods %}
 {% if method.should_be_exposed_to_script %}
 {% for world_suffix in method.world_suffixes %}
 {% if not method.is_custom and method.visible %}
 {{generate_method(method, world_suffix)}}
 {% endif %}
 {% if method.overloads and method.overloads.visible %}
+{% if method.overloads.runtime_determined_lengths %}
+{{runtime_determined_length_method(method.overloads)}}
+{% endif %}
 {{overload_resolution_method(method.overloads, world_suffix)}}
 {% endif %}
 {% if not method.overload_index or method.overloads %}
 {# Document about the following condition: #}
 {# https://docs.google.com/document/d/1qBC7Therp437Jbt_QYAtNYMZs6zQ_7_tnMkNUG_ACqs/edit?usp=sharing #}
 {% if (method.overloads and method.overloads.visible and
         (not method.overloads.has_partial_overloads or not is_partial)) or
       (not method.overloads and method.visible) %}
 {# A single callback is generated for overloaded methods #}
 {# with considering partial overloads #}
@@ skipping 295 matching lines @@
 {% endfor %}
 {% for attribute in attributes if attribute.is_implemented_in_private_script %}
 {{attribute_getter_implemented_in_private_script(attribute)}}
 {% if not attribute.is_read_only or attribute.put_forwards %}
 {{attribute_setter_implemented_in_private_script(attribute)}}
 {% endif %}
 {% endfor %}
 {% block partial_interface %}{% endblock %}
 } // namespace blink
 {% endfilter %}