Aura overlay scrollbars adjust color for dark backgrounds

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

Index: third_party/WebKit/Source/platform/scroll/ScrollableArea.h
diff --git a/third_party/WebKit/Source/platform/scroll/ScrollableArea.h b/third_party/WebKit/Source/platform/scroll/ScrollableArea.h
index d921b2d2da5ffc99455b6c1fbf51ea7aba599a2b..888aa52b49ace23f375cad17b6df3048d80a0f20 100644
--- a/third_party/WebKit/Source/platform/scroll/ScrollableArea.h
+++ b/third_party/WebKit/Source/platform/scroll/ScrollableArea.h
@@ -121,8 +121,10 @@ class PLATFORM_EXPORT ScrollableArea : public GarbageCollectedMixin {
 
   bool hasOverlayScrollbars() const;
   void setScrollbarOverlayStyle(ScrollbarOverlayStyle);
-  void recalculateScrollbarOverlayStyle(Color);
-  ScrollbarOverlayStyle getScrollbarOverlayStyle() const {
+  static ScrollbarOverlayStyle calculateScrollbarOverlayStyle(
+      Color backgroundColor);
+  void recalculateScrollbarOverlayStyle(Color, bool isTransparent);
+  virtual ScrollbarOverlayStyle getScrollbarOverlayStyle() const {
     return static_cast<ScrollbarOverlayStyle>(m_scrollbarOverlayStyle);
   }