Fix incorrect use of coords conversion for sticky elements

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

Index: third_party/WebKit/Source/core/paint/PaintLayer.cpp
diff --git a/third_party/WebKit/Source/core/paint/PaintLayer.cpp b/third_party/WebKit/Source/core/paint/PaintLayer.cpp
index d32a33b2099e1afdf3d1bd22c7f86039d7e7428b..6970d489fcac0acbc4cd83166bf325261c1113cb 100644
--- a/third_party/WebKit/Source/core/paint/PaintLayer.cpp
+++ b/third_party/WebKit/Source/core/paint/PaintLayer.cpp
@@ -1488,7 +1488,8 @@ static inline const PaintLayer* AccumulateOffsetTowardsAncestor(
 }
 
 void PaintLayer::ConvertToLayerCoords(const PaintLayer* ancestor_layer,
-                                      LayoutPoint& location) const {
+                                      LayoutPoint& location,
+                                      bool* is_descendant) const {
   if (ancestor_layer == this)
     return;
 
@@ -1496,6 +1497,9 @@ void PaintLayer::ConvertToLayerCoords(const PaintLayer* ancestor_layer,
   while (curr_layer && curr_layer != ancestor_layer)
     curr_layer =
         AccumulateOffsetTowardsAncestor(curr_layer, ancestor_layer, location);
+
+  if (is_descendant)
+    *is_descendant = curr_layer == ancestor_layer;
 }
 
 void PaintLayer::ConvertToLayerCoords(const PaintLayer* ancestor_layer,