Aura Overlay Scrollbars appear when mouse hovers over scroller edge

ui/native_theme/overlay_scrollbar_constants_aura.h

Index: ui/native_theme/overlay_scrollbar_constants_aura.h
diff --git a/ui/native_theme/overlay_scrollbar_constants_aura.h b/ui/native_theme/overlay_scrollbar_constants_aura.h
index 4022705dcb5971e6e2f1ef4d8a1db0082372506f..6d8ef45a4c3fe1d13fce5a2db49079ca2433edd8 100644
--- a/ui/native_theme/overlay_scrollbar_constants_aura.h
+++ b/ui/native_theme/overlay_scrollbar_constants_aura.h
@@ -14,6 +14,8 @@ constexpr int kOverlayScrollbarThumbWidthNormal = 6;
 constexpr int kOverlayScrollbarThumbWidthHovered = 10;
 constexpr int kOverlayScrollbarThumbWidthPressed = 10;
 
+constexpr base::TimeDelta kOverlayScrollbarFadeInDelay =

[bokan, 2017/02/27 23:13:56]

Could you add a comment describing this value and mentioning that it's only for
the case where the mouse hovers near the screen edge.

+    base::TimeDelta::FromMilliseconds(1000);
 constexpr base::TimeDelta kOverlayScrollbarFadeOutDelay =
     base::TimeDelta::FromMilliseconds(1000);
 constexpr base::TimeDelta kOverlayScrollbarFadeOutDuration =