add Tickmarks to aura overlay scrollbar

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

 /*
  * Copyright (c) 2009, 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 21 matching lines @@
 #define ScrollbarThemeAura_h
 
 #include "base/gtest_prod_util.h"
 #include "platform/scroll/ScrollbarTheme.h"
 
 namespace blink {
 
 class PLATFORM_EXPORT ScrollbarThemeAura : public ScrollbarTheme {
  public:
   int scrollbarThickness(ScrollbarControlSize) override;
+  static void paintAuraTickmarks(GraphicsContext&,

[bokan, 2016/11/04 19:46:25]

Lets just move this implementation into ScrollbarTheme and just override with an
empty implementation in Themes that shouldn't have it. By my count:

-ScrollbarThemeMac overrides with its own impl so that's fine

-ScrollbarThemeMock (and OverlayMock) previously didn't have it but if it
doesn't cause any tests to break it wont hurt to leave it in.

-ScrollbarThemeAndroid didn't have it either but maybe that's ok if it uses its
own implementation through a different path. In any case, we should override
with an empty impl and a comment describing where that happens on Android.

-ScrollbarThemeOverlay and ScrollbarThemeAura can just use the base version we
move into ScrollbarTheme

+                                 const Scrollbar&,
+                                 const IntRect&);
 
  protected:
   bool hasButtons(const ScrollbarThemeClient&) override { return true; }
   bool hasThumb(const ScrollbarThemeClient&) override;
 
   IntRect backButtonRect(const ScrollbarThemeClient&,
                          ScrollbarPart,
                          bool painting = false) override;
   IntRect forwardButtonRect(const ScrollbarThemeClient&,
                             ScrollbarPart,
@@ skipping 29 matching lines @@
   FRIEND_TEST_ALL_PREFIXES(ScrollbarThemeAuraTest, ButtonSizeVertical);
   FRIEND_TEST_ALL_PREFIXES(ScrollbarThemeAuraTest, NoButtonsReturnsSize0);
 
   virtual bool hasScrollbarButtons(ScrollbarOrientation) const;
   IntSize buttonSize(const ScrollbarThemeClient&);
 };
 
 }  // namespace blink
 
 #endif