LibWeb: Move enabled() to FormAssociatedElement and follow the spec

Userland/Libraries/LibWeb/HTML/FormAssociatedElement.cpp

@@ -5,7 +5,13 @@
  */
 
 #include <LibWeb/HTML/FormAssociatedElement.h>
+#include <LibWeb/HTML/HTMLButtonElement.h>
+#include <LibWeb/HTML/HTMLFieldSetElement.h>
 #include <LibWeb/HTML/HTMLFormElement.h>
+#include <LibWeb/HTML/HTMLInputElement.h>
+#include <LibWeb/HTML/HTMLLegendElement.h>
+#include <LibWeb/HTML/HTMLSelectElement.h>
+#include <LibWeb/HTML/HTMLTextAreaElement.h>
 
 namespace Web::HTML {
 
@@ -18,4 +24,25 @@ void FormAssociatedElement::set_form(HTMLFormElement* form)
         m_form->add_associated_element({}, *this);
 }
 
+bool FormAssociatedElement::enabled() const
+{
+    // https://html.spec.whatwg.org/multipage/form-control-infrastructure.html#concept-fe-disabled
+
+    // A form control is disabled if any of the following conditions are met:
+    // 1. The element is a button, input, select, textarea, or form-associated custom element, and the disabled attribute is specified on this element (regardless of its value).
+    // FIXME: This doesn't check for form-associated custom elements.
+    if ((is<HTMLButtonElement>(this) || is<HTMLInputElement>(this) || is<HTMLSelectElement>(this) || is<HTMLTextAreaElement>(this)) && has_attribute(HTML::AttributeNames::disabled))
+        return false;
+
+    // 2. The element is a descendant of a fieldset element whose disabled attribute is specified, and is not a descendant of that fieldset element's first legend element child, if any.
+    auto* fieldset_ancestor = first_ancestor_of_type<HTMLFieldSetElement>();
+    if (fieldset_ancestor && fieldset_ancestor->has_attribute(HTML::AttributeNames::disabled)) {
+        auto* first_legend_element_child = fieldset_ancestor->first_child_of_type<HTMLLegendElement>();
+        if (!first_legend_element_child || !is_descendant_of(*first_legend_element_child))
+            return false;
+    }
+
+    return true;
+}
+
 }

Userland/Libraries/LibWeb/HTML/FormAssociatedElement.h

@@ -19,6 +19,8 @@ public:
 
     void set_form(HTMLFormElement*);
 
+    bool enabled() const;
+
 protected:
     FormAssociatedElement(DOM::Document& document, DOM::QualifiedName qualified_name)
         : HTMLElement(document, move(qualified_name))

Userland/Libraries/LibWeb/HTML/HTMLInputElement.cpp

@@ -138,11 +138,6 @@ void HTMLInputElement::did_edit_text_node(Badge<BrowsingContext>)
     });
 }
 
-bool HTMLInputElement::enabled() const
-{
-    return !has_attribute(HTML::AttributeNames::disabled);
-}
-
 String HTMLInputElement::value() const
 {
     if (m_text_node)

Userland/Libraries/LibWeb/HTML/HTMLInputElement.h

@@ -73,8 +73,6 @@ public:
     };
     void set_checked(bool, ChangeSource = ChangeSource::Programmatic, ShouldRunActivationBehavior = ShouldRunActivationBehavior::Yes);
 
-    bool enabled() const;
-
     void did_click_button(Badge<Layout::ButtonBox>);
     void did_click_checkbox(Badge<Layout::CheckBox>);