Use new downcast helper for blink::HTMLDetailsElement

This CL has two goals,
1. Use To<HTMLDetailsElement> and DynamicTo<HTMLDetailsElement> as new
   downcast helper.
2. Use IsA<HTMLDetailsElement>(element) in place of
   IsHTMLDetailsElement(element)

Bug: 891908
Change-Id: Ib7d9bc62aced8df6158c3e04610e006996e9b28a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1738456Reviewed-by: Kentaro Hara <haraken@chromium.org>
Commit-Queue: Abhijeet Kandalkar <abhijeet@igalia.com>
Cr-Commit-Position: refs/heads/master@{#684355}

third_party/blink/renderer/core/dom/element.cc

@@ -272,7 +272,7 @@ bool DefinitelyNewFormattingContext(const Node& node,
     // type, though, and may end up disregarding the display type and just
     // create block containers. And those don't necessarily create a formatting
     // context.
-    if (!IsHTMLDetailsElement(node) && !IsHTMLSummaryElement(node))
+    if (!IsA<HTMLDetailsElement>(node) && !IsHTMLSummaryElement(node))
       return true;
   }
   if (!style.IsOverflowVisible())

third_party/blink/renderer/core/dom/slot_assignment.cc

@@ -22,7 +22,7 @@ namespace blink {
 
 namespace {
 bool ShouldAssignToCustomSlot(const Node& node) {
-  if (IsHTMLDetailsElement(node.parentElement()))
+  if (IsA<HTMLDetailsElement>(node.parentElement()))
     return HTMLDetailsElement::IsFirstSummary(node);
   if (IsHTMLSelectElement(node.parentElement()))
     return HTMLSelectElement::CanAssignToSelectSlot(node);

third_party/blink/renderer/core/html/html_details_element.cc

@@ -54,7 +54,7 @@ HTMLDetailsElement::~HTMLDetailsElement() = default;
 
 // static
 bool HTMLDetailsElement::IsFirstSummary(const Node& node) {
-  DCHECK(IsHTMLDetailsElement(node.parentElement()));
+  DCHECK(IsA<HTMLDetailsElement>(node.parentElement()));
   if (!IsHTMLSummaryElement(node))
     return false;
   return node.parentElement() &&

third_party/blink/renderer/core/html/html_summary_element.cc

@@ -67,9 +67,9 @@ void HTMLSummaryElement::DidAddUserAgentShadowRoot(ShadowRoot& root) {
 }
 
 HTMLDetailsElement* HTMLSummaryElement::DetailsElement() const {
-  if (auto* details = ToHTMLDetailsElementOrNull(parentNode()))
+  if (auto* details = DynamicTo<HTMLDetailsElement>(parentNode()))
     return details;
-  if (auto* details = ToHTMLDetailsElementOrNull(OwnerShadowHost()))
+  if (auto* details = DynamicTo<HTMLDetailsElement>(OwnerShadowHost()))
     return details;
   return nullptr;
 }

third_party/blink/renderer/modules/accessibility/ax_node_object.cc

@@ -498,7 +498,7 @@ ax::mojom::Role AXNodeObject::NativeRoleIgnoringAria() const {
     ContainerNode* parent = LayoutTreeBuilderTraversal::Parent(*GetNode());
     if (parent && IsHTMLSlotElement(parent))
       parent = LayoutTreeBuilderTraversal::Parent(*parent);
-    if (parent && IsHTMLDetailsElement(parent))
+    if (parent && IsA<HTMLDetailsElement>(parent))
       return ax::mojom::Role::kDisclosureTriangle;
     return ax::mojom::Role::kUnknown;
   }
@@ -1223,7 +1223,7 @@ AccessibilityExpanded AXNodeObject::IsExpanded() const {
 
   if (GetNode() && IsHTMLSummaryElement(*GetNode())) {
     if (GetNode()->parentNode() &&
-        IsHTMLDetailsElement(GetNode()->parentNode()))
+        IsA<HTMLDetailsElement>(GetNode()->parentNode()))
       return To<Element>(GetNode()->parentNode())->hasAttribute(kOpenAttr)
                  ? kExpandedExpanded
                  : kExpandedCollapsed;