Fix border radius on composited children.

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

Index: third_party/WebKit/Source/core/paint/PaintLayerClipper.cpp
diff --git a/third_party/WebKit/Source/core/paint/PaintLayerClipper.cpp b/third_party/WebKit/Source/core/paint/PaintLayerClipper.cpp
index 3f8a6de6090b6dedea8057046b768ba5a7b09be4..d3e32b324007a5fee898b2b78ced120a2ae3cbf6 100644
--- a/third_party/WebKit/Source/core/paint/PaintLayerClipper.cpp
+++ b/third_party/WebKit/Source/core/paint/PaintLayerClipper.cpp
@@ -345,9 +345,10 @@ void PaintLayerClipper::calculateRects(
 
   // Update the clip rects that will be passed to child layers.
   if (shouldClipOverflow(context)) {
-    foregroundRect.intersect(
+    LayoutRect offsetOverflowClipRect =
         toLayoutBox(layoutObject)
-            .overflowClipRect(offset, context.overlayScrollbarClipBehavior));
+            .overflowClipRect(offset, context.overlayScrollbarClipBehavior);
+    foregroundRect.intersect(offsetOverflowClipRect);
     if (layoutObject.styleRef().hasBorderRadius())
       foregroundRect.setHasRadius(true);