add Tickmarks to aura overlay scrollbar

third_party/WebKit/Source/platform/scroll/ScrollbarThemeMac.h

 /*
  * Copyright (C) 2008 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 36 matching lines @@
                           float autoscrollButtonDelay,
                           NSScrollerStyle preferredScrollerStyle,
                           bool redraw,
                           WebScrollbarButtonsPlacement);
 
   bool supportsControlTints() const override { return true; }
 
   double initialAutoscrollTimerDelay() override;
   double autoscrollTimerDelay() override;
 
   void paintTickmarks(GraphicsContext&,

[bokan, 2016/11/15 02:03:28]

Don't override paintTickmarks. Add a new method `virtual int
tickmarkBorderWidth()` and call it from paintTickmarks. Then just override
tickmarkBorderWidth in ScrollbarThemeMac

                       const Scrollbar&,
                       const IntRect&) override;
 
   bool shouldRepaintAllPartsOnInvalidation() const override { return false; }
   ScrollbarPart invalidateOnThumbPositionChange(
       const ScrollbarThemeClient&,
       float oldPosition,
       float newPosition) const override;
   void updateEnabledState(const ScrollbarThemeClient&) override;
   int scrollbarThickness(ScrollbarControlSize = RegularScrollbar) override;
@@ skipping 15 matching lines @@
 
  protected:
   int maxOverlapBetweenPages() override { return 40; }
 
   bool shouldDragDocumentInsteadOfThumb(const ScrollbarThemeClient&,
                                         const PlatformMouseEvent&) override;
   int scrollbarPartToHIPressedState(ScrollbarPart);
 
   virtual void updateButtonPlacement(WebScrollbarButtonsPlacement) {}
 
-  void paintGivenTickmarks(SkCanvas*,
-                           const Scrollbar&,
-                           const IntRect&,
-                           const Vector<IntRect>&);
-
   IntRect trackRect(const ScrollbarThemeClient&,
                     bool painting = false) override;
   IntRect backButtonRect(const ScrollbarThemeClient&,
                          ScrollbarPart,
                          bool painting = false) override;
   IntRect forwardButtonRect(const ScrollbarThemeClient&,
                             ScrollbarPart,
                             bool painting = false) override;
 
   bool hasButtons(const ScrollbarThemeClient&) override { return false; }
   bool hasThumb(const ScrollbarThemeClient&) override;
 
   int minimumThumbLength(const ScrollbarThemeClient&) override;
 
   RefPtr<Pattern> m_overhangPattern;
 };
 }
 
 #endif  // ScrollbarThemeMac_h