Aura overlay scrollbars adjust color for dark backgrounds

ui/native_theme/native_theme_base.h

Index: ui/native_theme/native_theme_base.h
diff --git a/ui/native_theme/native_theme_base.h b/ui/native_theme/native_theme_base.h
index 716f72e94261bbeac3893df189ca3463515b568e..4577af24458f43e117383716a9ceee194ee9abab 100644
--- a/ui/native_theme/native_theme_base.h
+++ b/ui/native_theme/native_theme_base.h
@@ -40,7 +40,8 @@ class NATIVE_THEME_EXPORT NativeThemeBase : public NativeTheme {
                             State startState,
                             State endState,
                             double progress,
-                            const gfx::Rect& rect) const override;
+                            const gfx::Rect& rect,
+                            ScrollbarOverlayColorTheme theme) const override;
 
  protected:
   NativeThemeBase();
@@ -65,7 +66,8 @@ class NATIVE_THEME_EXPORT NativeThemeBase : public NativeTheme {
       SkCanvas* canvas,
       Part part,
       State state,
-      const gfx::Rect& rect) const;
+      const gfx::Rect& rect,
+      NativeTheme::ScrollbarOverlayColorTheme theme) const;
 
   virtual void PaintScrollbarCorner(SkCanvas* canvas,
                                     State state,
@@ -136,13 +138,14 @@ class NATIVE_THEME_EXPORT NativeThemeBase : public NativeTheme {
       const gfx::Rect& rect,
       const ProgressBarExtraParams& progress_bar) const;
 
-  virtual void PaintScrollbarThumbStateTransition(SkCanvas* canvas,
-                                                  Part part,
-                                                  State startState,
-                                                  State endState,
-                                                  double progress,
-                                                  const gfx::Rect& rect) const {
-  }
+  virtual void PaintScrollbarThumbStateTransition(
+      SkCanvas* canvas,
+      Part part,
+      State startState,
+      State endState,
+      double progress,
+      const gfx::Rect& rect,
+      ScrollbarOverlayColorTheme theme) const {}
 
   // Shrinks checkbox/radio button rect, if necessary, to make room for padding
   // and drop shadow.