LibIDL: Allow overwriting the generated attribute callback name

This will allow the CSSStyleDeclaration IDL attribute generator to
implement it's own C++ acceptable identifier sanitization and
deduplication.

Libraries/LibIDL/IDLParser.cpp

@@ -326,8 +326,16 @@ void Parser::parse_attribute(HashMap<ByteString, ByteString>& extended_attribute
 
     assert_specific(';');
 
-    auto getter_callback_name = ByteString::formatted("{}_getter", name.to_snakecase());
-    auto setter_callback_name = ByteString::formatted("{}_setter", name.to_snakecase());
+    ByteString attribute_callback_name;
+    auto custom_callback_name = extended_attributes.find("AttributeCallbackName");
+    if (custom_callback_name != extended_attributes.end()) {
+        attribute_callback_name = custom_callback_name->value;
+    } else {
+        attribute_callback_name = name.to_snakecase().replace("-"sv, "_"sv, ReplaceMode::All);
+    }
+
+    auto getter_callback_name = ByteString::formatted("{}_getter", attribute_callback_name);
+    auto setter_callback_name = ByteString::formatted("{}_setter", attribute_callback_name);
 
     Attribute attribute {
         inherit,

Meta/Lagom/Tools/CodeGenerators/LibWeb/BindingsGenerator/IDLGenerators.cpp

@@ -2810,14 +2810,15 @@ static void generate_prototype_or_global_mixin_declarations(IDL::Interface const
         if (attribute.extended_attributes.contains("FIXME"))
             continue;
         auto attribute_generator = generator.fork();
-        attribute_generator.set("attribute.name:snakecase", attribute.name.to_snakecase());
+        attribute_generator.set("attribute.getter_callback", attribute.getter_callback_name);
         attribute_generator.append(R"~~~(
-    JS_DECLARE_NATIVE_FUNCTION(@attribute.name:snakecase@_getter);
+    JS_DECLARE_NATIVE_FUNCTION(@attribute.getter_callback@);
 )~~~");
 
         if (!attribute.readonly || attribute.extended_attributes.contains("Replaceable"sv) || attribute.extended_attributes.contains("PutForwards"sv)) {
+            attribute_generator.set("attribute.setter_callback", attribute.setter_callback_name);
             attribute_generator.append(R"~~~(
-    JS_DECLARE_NATIVE_FUNCTION(@attribute.name:snakecase@_setter);
+    JS_DECLARE_NATIVE_FUNCTION(@attribute.setter_callback@);
 )~~~");
         }
     }