IDL: Avoid generating empty ConstantConfiguration arrays

Source/bindings/templates/interface.cpp

 {% extends 'interface_base.cpp' %}
 
 
 {##############################################################################}
 {% macro attribute_configuration(attribute) %}
 {% set getter_callback =
        '%sV8Internal::%sAttributeGetterCallback' %
             (cpp_class, attribute.name)
        if not attribute.constructor_type else
        ('%sV8Internal::%sConstructorGetterCallback' %
@@ skipping 1061 matching lines @@
 {% set only_exposed_to_private_script = 'V8DOMConfiguration::OnlyExposedToPrivateScript' if method.only_exposed_to_private_script else 'V8DOMConfiguration::ExposedToAllScripts' %}
 static const V8DOMConfiguration::MethodConfiguration {{method.name}}MethodConfiguration = {
     "{{method.name}}", {{method_callback}}, {{method_callback_for_main_world}}, {{method.length}}, {{only_exposed_to_private_script}},
 };
 V8DOMConfiguration::installMethod({{method.function_template}}, {{method.signature}}, {{property_attribute}}, {{method.name}}MethodConfiguration, isolate);
 {%- endmacro %}
 
 
 {######################################}
 {% macro install_constants() %}
+{% if has_constant_configuration %}
 {# Normal (always enabled) constants #}
 static const V8DOMConfiguration::ConstantConfiguration {{v8_class}}Constants[] = {
     {% for constant in constants if not constant.runtime_enabled_function %}
     {% if constant.idl_type in ('Double', 'Float') %}
         {% set value = '0, %s, 0' % constant.value %}
     {% elif constant.idl_type == 'String' %}
         {% set value = '0, 0, %s' % constant.value %}
     {% else %}
         {# 'Short', 'Long' etc. #}
         {% set value = '%s, 0, 0' % constant.value %}
     {% endif %}
     {"{{constant.name}}", {{value}}, V8DOMConfiguration::ConstantType{{constant.idl_type}}},
     {% endfor %}
 };
 V8DOMConfiguration::installConstants(functionTemplate, prototypeTemplate, {{v8_class}}Constants, WTF_ARRAY_LENGTH({{v8_class}}Constants), isolate);
+{% endif %}
 {# Runtime-enabled constants #}
 {% for constant in constants if constant.runtime_enabled_function %}
 if ({{constant.runtime_enabled_function}}()) {
     {% if constant.idl_type in ('Double', 'Float') %}
         {% set value = '0, %s, 0' % constant.value %}
     {% elif constant.idl_type == 'String' %}
         {% set value = '0, 0, %s' % constant.value %}
     {% else %}
         {# 'Short', 'Long' etc. #}
         {% set value = '%s, 0, 0' % constant.value %}
@@ skipping 258 matching lines @@
 {% endif %}
 }
 
 template<>
 v8::Handle<v8::Value> toV8NoInline({{cpp_class}}* impl, v8::Handle<v8::Object> creationContext, v8::Isolate* isolate)
 {
     return toV8(impl, creationContext, isolate);
 }
 
 {% endblock %}