LibWeb: Cache HTMLInputElement's parsed type attribute when it changes

This will let us avoid parsing the type each time type() or type_state()
are invoked.

Userland/Libraries/LibWeb/HTML/HTMLInputElement.cpp

@@ -207,9 +207,25 @@ void HTMLInputElement::parse_attribute(FlyString const& name, String const& valu
         // the user agent must set the checkedness of the element to true
         if (!m_dirty_checkedness)
             set_checked(true, ChangeSource::Programmatic);
+    } else if (name == HTML::AttributeNames::type) {
+        m_type = parse_type_attribute(value);
     }
 }
 
+HTMLInputElement::TypeAttributeState HTMLInputElement::parse_type_attribute(StringView type)
+{
+#define __ENUMERATE_HTML_INPUT_TYPE_ATTRIBUTE(keyword, state) \
+    if (type.equals_ignoring_case(#keyword))                  \
+        return HTMLInputElement::TypeAttributeState::state;
+    ENUMERATE_HTML_INPUT_TYPE_ATTRIBUTES
+#undef __ENUMERATE_HTML_INPUT_TYPE_ATTRIBUTE
+
+    // The missing value default and the invalid value default are the Text state.
+    // https://html.spec.whatwg.org/multipage/input.html#the-input-element:missing-value-default
+    // https://html.spec.whatwg.org/multipage/input.html#the-input-element:invalid-value-default
+    return HTMLInputElement::TypeAttributeState::Text;
+}
+
 void HTMLInputElement::did_remove_attribute(FlyString const& name)
 {
     FormAssociatedElement::did_remove_attribute(name);

Userland/Libraries/LibWeb/HTML/HTMLInputElement.h

@@ -105,6 +105,7 @@ private:
     virtual void legacy_cancelled_activation_behavior() override;
     virtual void legacy_cancelled_activation_behavior_was_not_called() override;
 
+    static TypeAttributeState parse_type_attribute(StringView);
     void create_shadow_tree_if_needed();
     void run_input_activation_behavior();
     void set_checked_within_group();
@@ -121,6 +122,8 @@ private:
     // https://html.spec.whatwg.org/multipage/input.html#the-input-element:legacy-pre-activation-behavior
     bool m_before_legacy_pre_activation_behavior_checked { false };
     RefPtr<HTMLInputElement> m_legacy_pre_activation_behavior_checked_element_in_group;
+
+    TypeAttributeState m_type { TypeAttributeState::Text };
 };
 
 }