[WIP] IDL: Add limited serializer support and use for RTCIceCandidate

Source/bindings/templates/methods.cpp

 {% from 'conversions.cpp' import v8_value_to_local_cpp_value %}
 
 
 {##############################################################################}
 {% macro generate_method(method, world_suffix) %}
 {% filter conditional(method.conditional_string) %}
 {% if method.returns_promise and method.has_exception_state %}
 static void {{method.name}}{{method.overload_index}}Method{{world_suffix}}Promise(const v8::FunctionCallbackInfo<v8::Value>& info, ExceptionState& exceptionState)
 {% else %}
 static void {{method.name}}{{method.overload_index}}Method{{world_suffix}}(const v8::FunctionCallbackInfo<v8::Value>& info)
@@ skipping 226 matching lines @@
 Document& document = *toDocument(currentExecutionContext(info.GetIsolate()));
 {% endif %}
 {# Call #}
 {% if method.idl_type == 'void' %}
 {{cpp_value}};
 {% elif method.is_implemented_in_private_script %}
 {{method.cpp_type}} result{{method.cpp_type_initializer}};
 if (!{{method.cpp_value}})
     return;
 {% elif method.use_output_parameter_for_result %}
-{{method.cpp_type}} result;
+{{method.cpp_type}} result{{method.cpp_type_initializer}};
 {{cpp_value}};
 {% elif method.is_constructor %}
 {{method.cpp_type}} impl = {{cpp_value}};
 {% elif method.use_local_result %}
 {{method.cpp_type}} result = {{cpp_value}};
 {% endif %}
 {# Post-call #}
 {% if method.is_raises_exception %}
 if (exceptionState.hadException()) {
     {{propagate_error_with_exception_state(method) | indent}}
@@ skipping 395 matching lines @@
                               if method.overloads else
                               method.runtime_enabled_function) %}
     prototypeObject->Set(v8AtomicString(isolate, "{{method.name}}"), v8::FunctionTemplate::New(isolate, {{cpp_class_or_partial}}V8Internal::{{method.name}}MethodCallback, v8Undefined(), defaultSignature, {{method.number_of_required_arguments}})->GetFunction());
     {% endfilter %}{# runtime_enabled() #}
     {% endfilter %}{# exposed() #}
     {% endfilter %}{# per_context_enabled() #}
     {% endfor %}
     {% endif %}
 }
 {%- endmacro %}