LibWeb: Map all the IDL string types to AK::String for now

DOMString, CSSOMString and USVString can all map to AK::String for now,
until we figure something better out.

Userland/Libraries/LibWeb/CodeGenerators/WrapperGenerator.cpp

@@ -102,6 +102,7 @@ static size_t get_function_length(FunctionType& function)
 struct Type {
  String name;
  bool nullable { false };
+ bool is_string() const { return name.is_one_of("DOMString", "USVString", "CSSOMString"); }
 };
 
 struct Parameter {
@@ -517,7 +518,7 @@ static void generate_to_cpp(SourceGenerator& generator, ParameterType& parameter
  scoped_generator.set("return_statement", "return {};");
 
  // FIXME: Add support for optional to all types
- if (parameter.type.name == "DOMString") {
+ if (parameter.type.is_string()) {
  if (!optional) {
  scoped_generator.append(R"~~~(
  auto @cpp_name@ = @js_name@@[email protected]_string(global_object, @legacy_null_to_empty_string@);
@@ -1255,7 +1256,7 @@ static @fully_qualified_name@* impl_from(JS::VM& vm, JS::GlobalObject& global_ob
  }
 
  if (return_type.nullable) {
- if (return_type.name == "DOMString") {
+ if (return_type.is_string()) {
  scoped_generator.append(R"~~~(
  if (retval.is_null())
  return JS::js_null();
@@ -1268,7 +1269,7 @@ static @fully_qualified_name@* impl_from(JS::VM& vm, JS::GlobalObject& global_ob
  }
  }
 
- if (return_type.name == "DOMString") {
+ if (return_type.is_string()) {
  scoped_generator.append(R"~~~(
  return JS::js_string(vm, retval);
 )~~~");