Scrollbar width is set using thickness to compute correct rect size

third_party/WebKit/Source/core/paint/PaintLayerScrollableArea.cpp

Index: third_party/WebKit/Source/core/paint/PaintLayerScrollableArea.cpp
diff --git a/third_party/WebKit/Source/core/paint/PaintLayerScrollableArea.cpp b/third_party/WebKit/Source/core/paint/PaintLayerScrollableArea.cpp
index c7b948180fb715adbd86b7663e94cd60effbd650..1eff0d03b5f69ad73abafef6cab1dea943abfccb 100644
--- a/third_party/WebKit/Source/core/paint/PaintLayerScrollableArea.cpp
+++ b/third_party/WebKit/Source/core/paint/PaintLayerScrollableArea.cpp
@@ -949,7 +949,7 @@ IntRect PaintLayerScrollableArea::rectForHorizontalScrollbar(const IntRect& bord
     return IntRect(horizontalScrollbarStart(borderBoxRect.x()),
         borderBoxRect.maxY() - box().borderBottom() - horizontalScrollbar()->height(),
         borderBoxRect.width() - (box().borderLeft() + box().borderRight()) - scrollCorner.width(),
-        horizontalScrollbar()->height());
+        horizontalScrollbar()->scrollbarThickness());
 }
 
 IntRect PaintLayerScrollableArea::rectForVerticalScrollbar(const IntRect& borderBoxRect) const
@@ -961,7 +961,7 @@ IntRect PaintLayerScrollableArea::rectForVerticalScrollbar(const IntRect& border
 
     return IntRect(verticalScrollbarStart(borderBoxRect.x(), borderBoxRect.maxX()),
         borderBoxRect.y() + box().borderTop(),
-        verticalScrollbar()->width(),
+        verticalScrollbar()->scrollbarThickness(),
         borderBoxRect.height() - (box().borderTop() + box().borderBottom()) - scrollCorner.height());
 }