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

Source/platform/graphics/ContentLayerDelegate.h

Index: Source/platform/graphics/ContentLayerDelegate.h
diff --git a/Source/platform/graphics/ContentLayerDelegate.h b/Source/platform/graphics/ContentLayerDelegate.h
index 8843afda92e4a8776b37565121c723a3a9863a20..a49919ddd26e8d4f9cd4469f96c4816e571d9c34 100644
--- a/Source/platform/graphics/ContentLayerDelegate.h
+++ b/Source/platform/graphics/ContentLayerDelegate.h
@@ -53,11 +53,11 @@ class PLATFORM_EXPORT ContentLayerDelegate : public WebContentLayerClient {
 
 public:
     explicit ContentLayerDelegate(GraphicsContextPainter*);
-    virtual ~ContentLayerDelegate();
+    ~ContentLayerDelegate() override;
 
     // WebContentLayerClient implementation.
-    virtual void paintContents(SkCanvas*, const WebRect& clip, WebContentLayerClient::PaintingControlSetting = PaintDefaultBehavior) override;
-    virtual void paintContents(WebDisplayItemList*, const WebRect& clip, WebContentLayerClient::PaintingControlSetting = PaintDefaultBehavior) override;
+    void paintContents(SkCanvas*, const WebRect& clip, WebContentLayerClient::PaintingControlSetting = PaintDefaultBehavior) override;
+    void paintContents(WebDisplayItemList*, const WebRect& clip, WebContentLayerClient::PaintingControlSetting = PaintDefaultBehavior) override;
 
 private:
     GraphicsContextPainter* m_painter;