Fix virtual/override/final usage in Source/platform/.

Source/platform/graphics/paint/CompositingDisplayItem.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CompositingDisplayItem_h
 #define CompositingDisplayItem_h
 
 #include "platform/geometry/FloatRect.h"
 #include "platform/graphics/GraphicsTypes.h"
 #include "platform/graphics/paint/DisplayItem.h"
@@ skipping 11 matching lines @@
         : PairedBeginDisplayItem(client, BeginCompositing)
         , m_xferMode(xferMode)
         , m_opacity(opacity)
         , m_hasBounds(bounds)
         , m_colorFilter(colorFilter)
     {
         if (bounds)
             m_bounds = FloatRect(*bounds);
     }
 
-    virtual void replay(GraphicsContext&) override;
-    virtual void appendToWebDisplayItemList(WebDisplayItemList*) const override;
+    void replay(GraphicsContext&) override;
+    void appendToWebDisplayItemList(WebDisplayItemList*) const override;
 
 private:
 #ifndef NDEBUG
-    virtual void dumpPropertiesAsDebugString(WTF::StringBuilder&) const override;
+    void dumpPropertiesAsDebugString(WTF::StringBuilder&) const override;
 #endif
     const SkXfermode::Mode m_xferMode;
     const float m_opacity;
     bool m_hasBounds;
     FloatRect m_bounds;
     ColorFilter m_colorFilter;
 };
 
 class PLATFORM_EXPORT EndCompositingDisplayItem : public PairedEndDisplayItem {
 public:
     EndCompositingDisplayItem(const DisplayItemClientWrapper& client)
         : PairedEndDisplayItem(client, EndCompositing) { }
 
-    virtual void replay(GraphicsContext&) override;
-    virtual void appendToWebDisplayItemList(WebDisplayItemList*) const override;
+    void replay(GraphicsContext&) override;
+    void appendToWebDisplayItemList(WebDisplayItemList*) const override;
 
 private:
 #if ENABLE(ASSERT)
-    virtual bool isEndAndPairedWith(DisplayItem::Type otherType) const override final { return otherType == BeginCompositing; }
+    bool isEndAndPairedWith(DisplayItem::Type otherType) const final { return otherType == BeginCompositing; }
 #endif
 };
 
 } // namespace blink
 
 #endif // CompositingDisplayItem_h