Change Widget subclasses to use a CullRect instead of an IntRect for painting.

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

Index: third_party/WebKit/Source/core/paint/ScrollableAreaPainter.cpp
diff --git a/third_party/WebKit/Source/core/paint/ScrollableAreaPainter.cpp b/third_party/WebKit/Source/core/paint/ScrollableAreaPainter.cpp
index bd4e107f1a7b5ae5ed9895117dcbe465ab86533d..8b62703b457138f2882ac74ceaf50561467b90de 100644
--- a/third_party/WebKit/Source/core/paint/ScrollableAreaPainter.cpp
+++ b/third_party/WebKit/Source/core/paint/ScrollableAreaPainter.cpp
@@ -95,9 +95,6 @@ void ScrollableAreaPainter::paintOverflowControls(GraphicsContext* context, cons
     if (paintingOverlayControls)
         adjustedPaintOffset = scrollableArea().cachedOverlayScrollbarOffset();
 
-    IntRect localDamageRect = cullRect.m_rect;
-    localDamageRect.moveBy(-adjustedPaintOffset);
-
     CullRect adjustedCullRect(cullRect, -adjustedPaintOffset);
 
     // Overlay scrollbars paint in a second pass through the layer tree so that they will paint
@@ -131,11 +128,11 @@ void ScrollableAreaPainter::paintOverflowControls(GraphicsContext* context, cons
     {
         if (scrollableArea().horizontalScrollbar() && !scrollableArea().layerForHorizontalScrollbar()) {
             TransformRecorder translateRecorder(*context, *scrollableArea().horizontalScrollbar(), AffineTransform::translation(adjustedPaintOffset.x(), adjustedPaintOffset.y()));
-            scrollableArea().horizontalScrollbar()->paint(context, localDamageRect);
+            scrollableArea().horizontalScrollbar()->paint(context, adjustedCullRect);
         }
         if (scrollableArea().verticalScrollbar() && !scrollableArea().layerForVerticalScrollbar()) {
             TransformRecorder translateRecorder(*context, *scrollableArea().verticalScrollbar(), AffineTransform::translation(adjustedPaintOffset.x(), adjustedPaintOffset.y()));
-            scrollableArea().verticalScrollbar()->paint(context, localDamageRect);
+            scrollableArea().verticalScrollbar()->paint(context, adjustedCullRect);
         }
     }