Fix virtual/override/final usage in Source/core/html/.

Source/core/html/imports/HTMLImportChild.h

Index: Source/core/html/imports/HTMLImportChild.h
diff --git a/Source/core/html/imports/HTMLImportChild.h b/Source/core/html/imports/HTMLImportChild.h
index 5e892de29b54ba3c5ebd8c674ebab003e2aed9a5..543b63cc79722e59ff6be4ef3e663ac5ae391c7f 100644
--- a/Source/core/html/imports/HTMLImportChild.h
+++ b/Source/core/html/imports/HTMLImportChild.h
@@ -52,7 +52,7 @@ class HTMLLinkElement;
 class HTMLImportChild final : public HTMLImport {
 public:
     HTMLImportChild(const KURL&, HTMLImportLoader*, SyncMode);
-    virtual ~HTMLImportChild();
+    ~HTMLImportChild() override;
     void dispose();
 
     HTMLLinkElement* link() const;
@@ -66,15 +66,15 @@ public:
 #endif
 
     // HTMLImport
-    virtual Document* document() const override;
-    virtual bool hasFinishedLoading() const override;
-    virtual HTMLImportLoader* loader() const override;
-    virtual void stateWillChange() override;
-    virtual void stateDidChange() override;
+    Document* document() const override;
+    bool hasFinishedLoading() const override;
+    HTMLImportLoader* loader() const override;
+    void stateWillChange() override;
+    void stateDidChange() override;
     DECLARE_VIRTUAL_TRACE();
 
 #if !defined(NDEBUG)
-    virtual void showThis() override;
+    void showThis() override;
 #endif
 
     void setClient(HTMLImportChildClient*);