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

Source/core/html/imports/HTMLImportTreeRoot.h

Index: Source/core/html/imports/HTMLImportTreeRoot.h
diff --git a/Source/core/html/imports/HTMLImportTreeRoot.h b/Source/core/html/imports/HTMLImportTreeRoot.h
index 2562d5eec99638dba66c6111a3750a97ff317ab4..8274643c8327487e8630274e3da579894f15dde6 100644
--- a/Source/core/html/imports/HTMLImportTreeRoot.h
+++ b/Source/core/html/imports/HTMLImportTreeRoot.h
@@ -18,14 +18,14 @@ class HTMLImportTreeRoot : public HTMLImport {
 public:
     static PassOwnPtrWillBeRawPtr<HTMLImportTreeRoot> create(Document*);
 
-    virtual ~HTMLImportTreeRoot();
+    ~HTMLImportTreeRoot() override;
     void dispose();
 
     // HTMLImport
-    virtual Document* document() const override;
-    virtual bool hasFinishedLoading() const override;
-    virtual void stateWillChange() override;
-    virtual void stateDidChange() override;
+    Document* document() const override;
+    bool hasFinishedLoading() const override;
+    void stateWillChange() override;
+    void stateDidChange() override;
 
     void scheduleRecalcState();