LibWeb: Return a HTMLFormControlsCollection from HTMLFormElement element

Instead of a HTMLCollection

Tests/LibWeb/Text/expected/html-form-controls-collection.txt

@@ -0,0 +1,8 @@
+      HTMLFormControlsCollection
+RadioNodeList
+2
+button
+text
+null
+HTMLInputElement
+text

Tests/LibWeb/Text/input/html-form-controls-collection.html

@@ -0,0 +1,24 @@
+<form>
+  <input name="one" id="my-form-control" type="button" />
+  <input name="two" id="my-form-control" type="text" />
+</form>
+<script src="include.js"></script>
+<script>
+    test(() => {
+        const formElements = document.forms[0].elements;
+        const radioNodeList = formElements.namedItem("my-form-control");
+
+        println(formElements.constructor.name);
+        println(radioNodeList.constructor.name);
+        println(radioNodeList.length);
+        println(radioNodeList[0].type);
+        println(radioNodeList[1].type);
+
+        const nonMatching = formElements.namedItem("no match");
+        println(nonMatching);
+
+        const singleElement = formElements.namedItem("two");
+        println(singleElement.constructor.name);
+        println(singleElement.type);
+    })
+</script>

Userland/Libraries/LibWeb/HTML/HTMLFormElement.cpp

@@ -11,6 +11,7 @@
 #include <LibWeb/Bindings/ExceptionOrUtils.h>
 #include <LibWeb/DOM/Document.h>
 #include <LibWeb/DOM/Event.h>
+#include <LibWeb/DOM/HTMLFormControlsCollection.h>
 #include <LibWeb/HTML/BrowsingContext.h>
 #include <LibWeb/HTML/EventNames.h>
 #include <LibWeb/HTML/FormControlInfrastructure.h>
@@ -406,10 +407,10 @@ static bool is_form_control(DOM::Element const& element)
 }
 
 // https://html.spec.whatwg.org/multipage/forms.html#dom-form-elements
-JS::NonnullGCPtr<DOM::HTMLCollection> HTMLFormElement::elements() const
+JS::NonnullGCPtr<DOM::HTMLFormControlsCollection> HTMLFormElement::elements() const
 {
     if (!m_elements) {
-        m_elements = DOM::HTMLCollection::create(const_cast<HTMLFormElement&>(*this), DOM::HTMLCollection::Scope::Descendants, [](Element const& element) {
+        m_elements = DOM::HTMLFormControlsCollection::create(const_cast<HTMLFormElement&>(*this), DOM::HTMLCollection::Scope::Descendants, [](Element const& element) {
             return is_form_control(element);
         });
     }

Userland/Libraries/LibWeb/HTML/HTMLFormElement.h

@@ -67,7 +67,7 @@ public:
 
     ErrorOr<Vector<JS::NonnullGCPtr<DOM::Element>>> get_submittable_elements();
 
-    JS::NonnullGCPtr<DOM::HTMLCollection> elements() const;
+    JS::NonnullGCPtr<DOM::HTMLFormControlsCollection> elements() const;
     unsigned length() const;
 
     WebIDL::ExceptionOr<bool> check_validity();
@@ -110,7 +110,7 @@ private:
 
     Vector<JS::GCPtr<HTMLElement>> m_associated_elements;
 
-    JS::GCPtr<DOM::HTMLCollection> mutable m_elements;
+    JS::GCPtr<DOM::HTMLFormControlsCollection> mutable m_elements;
 
     bool m_constructing_entry_list { false };
 

Userland/Libraries/LibWeb/HTML/HTMLFormElement.idl

@@ -1,4 +1,4 @@
-#import <DOM/HTMLCollection.idl>
+#import <DOM/HTMLFormControlsCollection.idl>
 #import <HTML/HTMLElement.idl>
 
 // https://html.spec.whatwg.org/multipage/semantics.html#htmlformelement
@@ -20,8 +20,7 @@ interface HTMLFormElement : HTMLElement {
     boolean checkValidity();
     boolean reportValidity();
 
-    // FIXME: Should be a HTMLFormControlsCollection
-    [SameObject] readonly attribute HTMLCollection elements;
+    [SameObject] readonly attribute HTMLFormControlsCollection elements;
 
     readonly attribute unsigned long length;