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

Source/platform/graphics/Canvas2DLayerBridge.h

 /*
  * Copyright (C) 2012 Google 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
@@ skipping 35 matching lines @@
 class Canvas2DLayerBridgeTest;
 class ImageBuffer;
 class WebGraphicsContext3D;
 class WebGraphicsContext3DProvider;
 
 class PLATFORM_EXPORT Canvas2DLayerBridge : public WebExternalTextureLayerClient, public SkDeferredCanvas::NotificationClient, public DoublyLinkedListNode<Canvas2DLayerBridge>, public RefCounted<Canvas2DLayerBridge> {
     WTF_MAKE_NONCOPYABLE(Canvas2DLayerBridge);
 public:
     static PassRefPtr<Canvas2DLayerBridge> create(const IntSize&, OpacityMode, int msaaSampleCount);
 
-    virtual ~Canvas2DLayerBridge();
+    ~Canvas2DLayerBridge() override;
 
     // WebExternalTextureLayerClient implementation.
-    virtual bool prepareMailbox(WebExternalTextureMailbox*, WebExternalBitmap*) override;
-    virtual void mailboxReleased(const WebExternalTextureMailbox&, bool lostResource) override;
+    bool prepareMailbox(WebExternalTextureMailbox*, WebExternalBitmap*) override;
+    void mailboxReleased(const WebExternalTextureMailbox&, bool lostResource) override;
 
     // SkDeferredCanvas::NotificationClient implementation
-    virtual void prepareForDraw() override;
-    virtual void storageAllocatedForRecordingChanged(size_t) override;
-    virtual void flushedDrawCommands() override;
-    virtual void skippedPendingDrawCommands() override;
+    void prepareForDraw() override;
+    void storageAllocatedForRecordingChanged(size_t) override;
+    void flushedDrawCommands() override;
+    void skippedPendingDrawCommands() override;
 
     // ImageBufferSurface implementation
     void finalizeFrame(const FloatRect &dirtyRect);
     void willAccessPixels();
     SkCanvas* canvas() const { return m_canvas.get(); }
     bool checkSurfaceValid();
     bool restoreSurface();
     WebLayer* layer() const;
     bool isAccelerated() const { return true; }
     void setFilterQuality(SkFilterQuality);
@@ skipping 59 matching lines @@
     };
 
     Deque<MailboxInfo, MaxActiveMailboxes> m_mailboxes;
     GLenum m_lastFilter;
     OpacityMode m_opacityMode;
 };
 
 } // namespace blink
 
 #endif