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

Source/platform/scroll/ScrollbarThemeNonMacCommon.h

Index: Source/platform/scroll/ScrollbarThemeNonMacCommon.h
diff --git a/Source/platform/scroll/ScrollbarThemeNonMacCommon.h b/Source/platform/scroll/ScrollbarThemeNonMacCommon.h
index cde17190b21613355fd91a9bd3f9ff28a1458d42..104fd2ae6a9362c6ee273fe81fceca20c01655a0 100644
--- a/Source/platform/scroll/ScrollbarThemeNonMacCommon.h
+++ b/Source/platform/scroll/ScrollbarThemeNonMacCommon.h
@@ -37,15 +37,15 @@ namespace blink {
 
 class PLATFORM_EXPORT ScrollbarThemeNonMacCommon : public ScrollbarTheme {
 protected:
-    virtual bool hasButtons(ScrollbarThemeClient*) override { return true; }
-    virtual bool hasThumb(ScrollbarThemeClient*) override;
+    bool hasButtons(ScrollbarThemeClient*) override { return true; }
+    bool hasThumb(ScrollbarThemeClient*) override;
 
-    virtual IntRect backButtonRect(ScrollbarThemeClient*, ScrollbarPart, bool painting = false) override;
-    virtual IntRect forwardButtonRect(ScrollbarThemeClient*, ScrollbarPart, bool painting = false) override;
-    virtual IntRect trackRect(ScrollbarThemeClient*, bool painting = false) override;
+    IntRect backButtonRect(ScrollbarThemeClient*, ScrollbarPart, bool painting = false) override;
+    IntRect forwardButtonRect(ScrollbarThemeClient*, ScrollbarPart, bool painting = false) override;
+    IntRect trackRect(ScrollbarThemeClient*, bool painting = false) override;
 
-    virtual void paintTrackBackground(GraphicsContext*, ScrollbarThemeClient*, const IntRect&) override;
-    virtual void paintTickmarks(GraphicsContext*, ScrollbarThemeClient*, const IntRect&) override;
+    void paintTrackBackground(GraphicsContext*, ScrollbarThemeClient*, const IntRect&) override;
+    void paintTickmarks(GraphicsContext*, ScrollbarThemeClient*, const IntRect&) override;
 
     virtual IntSize buttonSize(ScrollbarThemeClient*) = 0;
 };