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

Source/core/layout/LayoutFullScreen.cpp

 /*
  * Copyright (C) 2010 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
  *     notice, this list of conditions and the following disclaimer in the
@@ skipping 26 matching lines @@
 
 class LayoutFullScreenPlaceholder final : public LayoutBlockFlow {
 public:
     LayoutFullScreenPlaceholder(LayoutFullScreen* owner)
         : LayoutBlockFlow(nullptr)
         , m_owner(owner)
     {
         setDocumentForAnonymous(&owner->document());
     }
 private:
-    virtual bool isOfType(LayoutObjectType type) const override { return type == LayoutObjectLayoutFullScreenPlaceholder || LayoutBlockFlow::isOfType(type); }
-    virtual void willBeDestroyed() override;
+    bool isOfType(LayoutObjectType type) const override { return type == LayoutObjectLayoutFullScreenPlaceholder || LayoutBlockFlow::isOfType(type); }
+    void willBeDestroyed() override;
     LayoutFullScreen* m_owner;
 };
 
 void LayoutFullScreenPlaceholder::willBeDestroyed()
 {
     m_owner->setPlaceholder(nullptr);
     LayoutBlockFlow::willBeDestroyed();
 }
 
 LayoutFullScreen::LayoutFullScreen()
@@ skipping 135 matching lines @@
         m_placeholder = new LayoutFullScreenPlaceholder(this);
         m_placeholder->setStyle(style);
         if (parent()) {
             parent()->addChild(m_placeholder, this);
             parent()->setNeedsLayoutAndPrefWidthsRecalcAndFullPaintInvalidation(LayoutInvalidationReason::Fullscreen);
         }
     } else {
         m_placeholder->setStyle(style);
     }
 }