Fix overflow:overlay scrollbar width for paint.

third_party/WebKit/Source/core/layout/compositing/CompositedLayerMapping.cpp

Index: third_party/WebKit/Source/core/layout/compositing/CompositedLayerMapping.cpp
diff --git a/third_party/WebKit/Source/core/layout/compositing/CompositedLayerMapping.cpp b/third_party/WebKit/Source/core/layout/compositing/CompositedLayerMapping.cpp
index 84f64b1d3bc19c228698baa43e2c857d17b93c23..e6d0ca0144470c1fc16ad5232bdba202f1426bdc 100644
--- a/third_party/WebKit/Source/core/layout/compositing/CompositedLayerMapping.cpp
+++ b/third_party/WebKit/Source/core/layout/compositing/CompositedLayerMapping.cpp
@@ -545,7 +545,7 @@ void CompositedLayerMapping::
   // FIXME: this should use cached clip rects, but this sometimes give
   // inaccurate results (and trips the ASSERTS in PaintLayerClipper).
   ClipRectsContext clipRectsContext(compositingAncestor, UncachedClipRects,
-                                    IgnoreOverlayScrollbarSize);
+                                    IgnorePlatformOverlayScrollbarSize);
   clipRectsContext.setIgnoreOverflowClip();
   LayoutRect unsnappedParentClipRect =
       m_owningLayer.clipper(PaintLayer::DoNotUseGeometryMapper)
@@ -1143,7 +1143,7 @@ void CompositedLayerMapping::updateAncestorClippingLayerGeometry(
 
   ClipRectsContext clipRectsContext(compositingContainer,
                                     PaintingClipRectsIgnoringOverflowClip,
-                                    IgnoreOverlayScrollbarSize);
+                                    IgnorePlatformOverlayScrollbarSize);
   IntRect parentClipRect = pixelSnappedIntRect(
       m_owningLayer.clipper(PaintLayer::DoNotUseGeometryMapper)
           .backgroundClipRect(clipRectsContext)