LibWeb: Make Node::parent_element return GC::Ptr

This is useful for people like myself who run with debug mode to
more reliably get stacktraces without spinning up a debugger.

Libraries/LibWeb/HTML/HTMLElement.cpp

@@ -467,15 +467,15 @@ GC::Ptr<DOM::Element> HTMLElement::offset_parent() const
     //    - The computed value of the position property of the element is static
     //      and the ancestor is one of the following HTML elements: td, th, or table.
 
-    for (auto* ancestor = parent_element(); ancestor; ancestor = ancestor->parent_element()) {
+    for (auto ancestor = parent_element(); ancestor; ancestor = ancestor->parent_element()) {
         if (!ancestor->layout_node())
             continue;
         if (ancestor->layout_node()->is_positioned())
-            return const_cast<Element*>(ancestor);
+            return const_cast<Element*>(ancestor.ptr());
         if (is<HTML::HTMLBodyElement>(*ancestor))
-            return const_cast<Element*>(ancestor);
+            return const_cast<Element*>(ancestor.ptr());
         if (!ancestor->layout_node()->is_positioned() && ancestor->local_name().is_one_of(HTML::TagNames::td, HTML::TagNames::th, HTML::TagNames::table))
-            return const_cast<Element*>(ancestor);
+            return const_cast<Element*>(ancestor.ptr());
     }
 
     // 3. Return null.
@@ -843,7 +843,7 @@ Optional<ARIA::Role> HTMLElement::default_role() const
     // https://www.w3.org/TR/html-aria/#el-aside
     if (local_name() == TagNames::aside) {
         // https://w3c.github.io/html-aam/#el-aside
-        for (auto const* ancestor = parent_element(); ancestor; ancestor = ancestor->parent_element()) {
+        for (auto ancestor = parent_element(); ancestor; ancestor = ancestor->parent_element()) {
             if (ancestor->local_name().is_one_of(TagNames::article, TagNames::aside, TagNames::nav, TagNames::section)
                 && accessible_name(document()).value().is_empty())
                 return ARIA::Role::generic;
@@ -887,7 +887,7 @@ Optional<ARIA::Role> HTMLElement::default_role() const
         // If not a descendant of an article, aside, main, nav or section element, or an element with role=article,
         // complementary, main, navigation or region then (footer) role=contentinfo (header) role=banner. Otherwise,
         // role=generic.
-        for (auto const* ancestor = parent_element(); ancestor; ancestor = ancestor->parent_element()) {
+        for (auto ancestor = parent_element(); ancestor; ancestor = ancestor->parent_element()) {
             if (ancestor->local_name().is_one_of(TagNames::article, TagNames::aside, TagNames::main, TagNames::nav, TagNames::section)) {
                 if (local_name() == TagNames::footer)
                     return ARIA::Role::sectionfooter;

Libraries/LibWeb/HTML/HTMLLIElement.h

@@ -24,7 +24,7 @@ public:
     // https://www.w3.org/TR/html-aria/#el-li
     virtual Optional<ARIA::Role> default_role() const override
     {
-        for (auto const* ancestor = parent_element(); ancestor; ancestor = ancestor->parent_element()) {
+        for (auto ancestor = parent_element(); ancestor; ancestor = ancestor->parent_element()) {
             if (ancestor->role_or_default() == ARIA::Role::list)
                 return ARIA::Role::listitem;
         }

Libraries/LibWeb/HTML/HTMLLegendElement.cpp

@@ -32,8 +32,8 @@ HTMLFormElement* HTMLLegendElement::form()
 {
     // The form IDL attribute's behavior depends on whether the legend element is in a fieldset element or not.
     // If the legend has a fieldset element as its parent, then the form IDL attribute must return the same value as the form IDL attribute on that fieldset element.
-    if (is<HTML::HTMLFieldSetElement>(parent_element())) {
-        return as<HTML::HTMLFieldSetElement>(parent_element())->form();
+    if (auto* field_set = as_if<HTML::HTMLFieldSetElement>(parent_element().ptr())) {
+        return field_set->form();
     }
 
     // Otherwise, it must return null.

Libraries/LibWeb/HTML/HTMLOptionElement.cpp

@@ -250,7 +250,7 @@ void HTMLOptionElement::removed_from(Node* old_parent, Node& old_root)
     if (old_parent) {
         if (is<HTMLSelectElement>(*old_parent))
             static_cast<HTMLSelectElement&>(*old_parent).update_selectedness();
-        else if (is<HTMLOptGroupElement>(*old_parent) && old_parent->parent_element() && is<HTMLSelectElement>(old_parent->parent_element()))
+        else if (is<HTMLOptGroupElement>(*old_parent) && old_parent->parent_element() && is<HTMLSelectElement>(*old_parent->parent_element()))
             static_cast<HTMLSelectElement&>(*old_parent->parent_element()).update_selectedness();
     }
 }

Libraries/LibWeb/HTML/HTMLSummaryElement.cpp

@@ -31,7 +31,7 @@ void HTMLSummaryElement::activation_behavior(DOM::Event const&)
         return;
 
     // 2. Let parent be this summary element's parent.
-    auto* parent = this->parent_element();
+    auto parent = this->parent_element();
 
     // 3. If the open attribute is present on parent, then remove it. Otherwise, set parent's open attribute to the empty string.
     if (parent->has_attribute(HTML::AttributeNames::open))
@@ -50,7 +50,7 @@ bool HTMLSummaryElement::is_summary_for_its_parent_details()
         return false;
 
     // 2. Let parent be this summary element's parent.
-    auto* parent = this->parent_element();
+    auto parent = this->parent_element();
 
     // 3. If parent is not a details element, then return false.
     if (!is<HTMLDetailsElement>(*parent))

Libraries/LibWeb/HTML/HTMLTableCellElement.cpp

@@ -215,7 +215,7 @@ WebIDL::Long HTMLTableCellElement::cell_index() const
 Optional<ARIA::Role> HTMLTableCellElement::default_role() const
 {
     if (local_name() == TagNames::th) {
-        for (auto const* ancestor = parent_element(); ancestor; ancestor = ancestor->parent_element()) {
+        for (auto ancestor = parent_element(); ancestor; ancestor = ancestor->parent_element()) {
             // AD-HOC: The ancestor checks here aren’t explicitly defined in the spec, but implicitly follow from what
             // the spec does state, and from the physical placement/layout of elements. Also, the el-th and el-th-in-row
             // tests at https://wpt.fyi/results/html-aam/table-roles.html require doing these ancestor checks — and

Libraries/LibWeb/HTML/HTMLTrackElement.cpp

@@ -151,7 +151,7 @@ void HTMLTrackElement::start_the_track_processing_model()
         return;
 
     // 3. If the text track's track element does not have a media element as a parent, return.
-    if (!is<HTMLMediaElement>(parent_element()))
+    if (!is<HTMLMediaElement>(parent_element().ptr()))
         return;
 
     // 4. Run the remainder of these steps in parallel, allowing whatever caused these steps to run to continue.