Use new downcast helpers for blink::SpinButtonElement

Bug: 891908
Change-Id: I2107c9975d3605a4937d4e6946d8ea716fab2789
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1652391
Commit-Queue: Abhijeet Kandalkar <abhijeet@igalia.com>
Reviewed-by: Jeremy Roman <jbroman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#668491}

third_party/blink/renderer/core/html/forms/spin_button_element.h

@@ -102,16 +102,11 @@ class CORE_EXPORT SpinButtonElement final : public HTMLDivElement,
   TaskRunnerTimer<SpinButtonElement> repeating_timer_;
 };
 
-DEFINE_TYPE_CASTS(SpinButtonElement,
-                  Node,
-                  node,
-                  To<Element>(node)->IsSpinButtonElement(),
-                  To<Element>(node).IsSpinButtonElement());
-
 template <>
 struct DowncastTraits<SpinButtonElement> {
   static bool AllowFrom(const Node& node) {
-    return ToElement(node).IsSpinButtonElement();
+    auto* element = DynamicTo<Element>(node);
+    return element && element->IsSpinButtonElement();
   }
 };
 

third_party/blink/renderer/core/layout/layout_theme.cc

@@ -378,7 +378,7 @@ bool LayoutTheme::IsSpinUpButtonPartPressed(const Node* node) {
   if (!node || !node->IsActive() || !node->IsElementNode() ||
       !ToElement(node)->IsSpinButtonElement())
     return false;
-  const SpinButtonElement* element = ToSpinButtonElement(node);
+  const auto* element = To<SpinButtonElement>(node);
   return element->GetUpDownState() == SpinButtonElement::kUp;
 }
 
@@ -395,7 +395,7 @@ bool LayoutTheme::IsHovered(const Node* node) {
     return false;
   if (!node->IsElementNode() || !ToElement(node)->IsSpinButtonElement())
     return node->IsHovered();
-  const SpinButtonElement* element = ToSpinButtonElement(node);
+  const auto* element = To<SpinButtonElement>(node);
   return element->IsHovered() &&
          element->GetUpDownState() != SpinButtonElement::kIndeterminate;
 }
@@ -404,7 +404,7 @@ bool LayoutTheme::IsSpinUpButtonPartHovered(const Node* node) {
   if (!node || !node->IsElementNode() ||
       !ToElement(node)->IsSpinButtonElement())
     return false;
-  const SpinButtonElement* element = ToSpinButtonElement(node);
+  const auto* element = To<SpinButtonElement>(node);
   return element->GetUpDownState() == SpinButtonElement::kUp;
 }