Remove unnecessary override of Node#cloneNode in ShadowRoot's WebIDL

third_party/WebKit/Source/core/dom/shadow/ShadowRoot.h

Index: third_party/WebKit/Source/core/dom/shadow/ShadowRoot.h
diff --git a/third_party/WebKit/Source/core/dom/shadow/ShadowRoot.h b/third_party/WebKit/Source/core/dom/shadow/ShadowRoot.h
index 420e4a08172bf2773c0d06cab780e0987ba76dd9..c8bcbda9b237b5c3a0bf866e192b4e2577278ed4 100644
--- a/third_party/WebKit/Source/core/dom/shadow/ShadowRoot.h
+++ b/third_party/WebKit/Source/core/dom/shadow/ShadowRoot.h
@@ -140,7 +140,7 @@ class CORE_EXPORT ShadowRoot final : public DocumentFragment, public TreeScope {
   String innerHTML() const;
   void setInnerHTML(const String&, ExceptionState& = ASSERT_NO_EXCEPTION);
 
-  Node* cloneNode(bool, ExceptionState&);
+  Node* cloneNode(bool, ExceptionState&) override;
 
   void setDelegatesFocus(bool flag) { m_delegatesFocus = flag; }
   bool delegatesFocus() const { return m_delegatesFocus; }
@@ -172,9 +172,6 @@ class CORE_EXPORT ShadowRoot final : public DocumentFragment, public TreeScope {
   }
   void invalidateDescendantInsertionPoints();
 
-  // ShadowRoots should never be cloned.
-  Node* cloneNode(bool) override { return nullptr; }
-
   Member<ShadowRootRareDataV0> m_shadowRootRareDataV0;
   Member<StyleSheetList> m_styleSheetList;
   Member<SlotAssignment> m_slotAssignment;