Overlay scrollbars flush with window edge

content/child/webthemeengine_impl_default.cc

Index: content/child/webthemeengine_impl_default.cc
diff --git a/content/child/webthemeengine_impl_default.cc b/content/child/webthemeengine_impl_default.cc
index 6014d2b3072dc1736959040af04788d9c6140649..9bf10502afd35d26cb865d4e9ec1ce83e502bcb5 100644
--- a/content/child/webthemeengine_impl_default.cc
+++ b/content/child/webthemeengine_impl_default.cc
@@ -199,6 +199,14 @@ static void GetNativeThemeExtraParams(
       native_theme_extra_params->scrollbar_thumb.scrollbar_theme =
           NativeThemeScrollbarOverlayColorTheme(
               extra_params->scrollbarThumb.scrollbarTheme);
+      native_theme_extra_params->scrollbar_thumb.isVerticalScrollbar =
+          extra_params->scrollbarThumb.isVerticalScrollbar;
+      native_theme_extra_params->scrollbar_thumb.isLeftVerticalScrollbar =
+          extra_params->scrollbarThumb.isLeftVerticalScrollbar;
+      native_theme_extra_params->scrollbar_thumb.hitStart =
+          extra_params->scrollbarThumb.hitStart;
+      native_theme_extra_params->scrollbar_thumb.hitEnd =
+          extra_params->scrollbarThumb.hitEnd;
       break;
     default:
       break;  // Parts that have no extra params get here.