Fix nested border radius with composited child.

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

Index: third_party/WebKit/Source/core/layout/compositing/CompositedLayerMapping.h
diff --git a/third_party/WebKit/Source/core/layout/compositing/CompositedLayerMapping.h b/third_party/WebKit/Source/core/layout/compositing/CompositedLayerMapping.h
index e5a74bee86a38da034dc05cf5d517a90b2e62219..49acded2327c41131318ebe80ee6df60aa3e7eb9 100644
--- a/third_party/WebKit/Source/core/layout/compositing/CompositedLayerMapping.h
+++ b/third_party/WebKit/Source/core/layout/compositing/CompositedLayerMapping.h
@@ -488,16 +488,6 @@ class CORE_EXPORT CompositedLayerMapping final : public GraphicsLayerClient {
       const GraphicsLayerPaintInfo&,
       const Vector<GraphicsLayerPaintInfo>& layers);
 
-  // Conservatively check that a border-radius clip does not clip a child.
-  // This is a fast approximate test. Depending on the shape of the child and
-  // the size of the border radius, this method may return false when in fact
-  // the child is not clipped. We accept the approximation because most border
-  // radii are small and the outcome is used to reduce the number of layers,
-  // not influence correctness.
-  bool AncestorRoundedCornersWontClip(
-      const LayoutBoxModelObject& child,
-      const LayoutBoxModelObject& clipping_ancestor);
-
   // Return true in |owningLayerIsClipped| iff |m_owningLayer|'s compositing
   // ancestor is not a descendant (inclusive) of the clipping container for
   // |m_owningLayer|. Return true in |owningLayerIsMasked| iff