bindings: Ignores the last undefined arguments when counting the args.

third_party/WebKit/Source/bindings/templates/methods.cpp

 {% from 'conversions.cpp' import declare_enum_validation_variable, 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 56 matching lines @@
 {% endfilter %}
 {% endmacro %}
 
 
 {######################################}
 {% macro generate_arguments(method, world_suffix) %}
 {% for argument in method.arguments %}
 {{generate_argument_var_declaration(argument)}};
 {% endfor %}
 {
+    {% if method.has_optional_argument_without_default_value %}
+    {# Count the effective number of arguments.  (arg1, arg2, undefined) is
+       interpreted as two arguments are passed and (arg1, undefined, arg3) is
+       interpreted as three arguments are passed. #}
+    int numArgsPassed = info.Length();
+    while (numArgsPassed > 0) {
+        if (!info[numArgsPassed - 1]->IsUndefined())
+            break;
+        --numArgsPassed;
+    }
+    {% endif %}
     {% for argument in method.arguments %}
     {% if argument.set_default_value %}
     if (!info[{{argument.index}}]->IsUndefined()) {
         {{generate_argument(method, argument, world_suffix) | indent(8)}}
     } else {
         {{argument.set_default_value}};
     }
     {% else %}
     {{generate_argument(method, argument, world_suffix) | indent}}
     {% endif %}
     {% endfor %}
 }
 {% endmacro %}
 
 
 {######################################}
 {% macro generate_argument_var_declaration(argument) %}
 {# FIXME: remove EventListener special case #}
 {% if argument.idl_type == 'EventListener' %}
 RefPtrWillBeRawPtr<{{argument.idl_type}}> {{argument.name}}
 {%- else %}
 {{argument.cpp_type}} {{argument.name}}
 {%- endif %}{# argument.idl_type == 'EventListener' #}
 {% endmacro %}
 
 
 {######################################}
 {% macro generate_argument(method, argument, world_suffix) %}
-{% if argument.is_optional and not argument.has_default and
-      not argument.is_dictionary and
-      not argument.is_callback_interface %}
+{% if argument.is_optional_without_default_value %}
 {# Optional arguments without a default value generate an early call with
    fewer arguments if they are omitted.
    Optional Dictionary arguments default to empty dictionary. #}
-if (UNLIKELY(info.Length() <= {{argument.index}})) {
+if (UNLIKELY(numArgsPassed <= {{argument.index}})) {
     {% if world_suffix %}
     {{cpp_method_call(method, argument.v8_set_return_value_for_main_world, argument.cpp_value) | indent}}
     {% else %}
     {{cpp_method_call(method, argument.v8_set_return_value, argument.cpp_value) | indent}}
     {% endif %}
     {% if argument.has_event_listener_argument %}
     {{hidden_dependency_action(method.name) | indent}}
     {% endif %}
     return;
 }
@@ skipping 561 matching lines @@
 {% filter runtime_enabled(method.overloads.runtime_enabled_function_all
                           if method.overloads else
                           method.runtime_enabled_function) %}
 const V8DOMConfiguration::MethodConfiguration {{method.name}}MethodConfiguration = {{method_configuration(method)}};
 V8DOMConfiguration::installMethod(isolate, v8::Local<v8::Object>(), prototypeObject, interfaceObject, defaultSignature, {{method.name}}MethodConfiguration);
 {% endfilter %}{# runtime_enabled() #}
 {% endfilter %}{# exposed() #}
 {% endfor %}
 {% endif %}
 {%- endmacro %}