Fix virtual/override/final usage in the rest of Source/core/.

Source/core/page/CustomContextMenuProvider.h

Index: Source/core/page/CustomContextMenuProvider.h
diff --git a/Source/core/page/CustomContextMenuProvider.h b/Source/core/page/CustomContextMenuProvider.h
index f7d1a6379e4a491b3e49d6a1ce59942935b9f6b1..08745f63234d4ea2ffe2012923e74cc5ef2d47e1 100644
--- a/Source/core/page/CustomContextMenuProvider.h
+++ b/Source/core/page/CustomContextMenuProvider.h
@@ -18,7 +18,7 @@ class HTMLMenuItemElement;
 
 class CustomContextMenuProvider final : public ContextMenuProvider {
 public:
-    virtual ~CustomContextMenuProvider();
+    ~CustomContextMenuProvider() override;
 
     static PassRefPtrWillBeRawPtr<CustomContextMenuProvider> create(HTMLMenuElement& menu, HTMLElement& subject)
     {
@@ -30,9 +30,9 @@ public:
 private:
     CustomContextMenuProvider(HTMLMenuElement&, HTMLElement&);
 
-    virtual void populateContextMenu(ContextMenu*) override;
-    virtual void contextMenuItemSelected(const ContextMenuItem*) override;
-    virtual void contextMenuCleared() override;
+    void populateContextMenu(ContextMenu*) override;
+    void contextMenuItemSelected(const ContextMenuItem*) override;
+    void contextMenuCleared() override;
     void populateContextMenuItems(const HTMLMenuElement&, ContextMenu&);
     void appendSeparator(ContextMenu&);
     void appendMenuItem(HTMLMenuItemElement*, ContextMenu&);