Fix border radius on composited children.

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

Index: third_party/WebKit/Source/core/paint/LayerClipRecorder.cpp
diff --git a/third_party/WebKit/Source/core/paint/LayerClipRecorder.cpp b/third_party/WebKit/Source/core/paint/LayerClipRecorder.cpp
index 44470cca68a5ce631f99b1453e85e930080470b5..9e33e9b87324b19f0a11540024748c4bb3613513 100644
--- a/third_party/WebKit/Source/core/paint/LayerClipRecorder.cpp
+++ b/third_party/WebKit/Source/core/paint/LayerClipRecorder.cpp
@@ -71,6 +71,18 @@ void LayerClipRecorder::collectRoundedRectClips(PaintLayer& paintLayer, const Pa
         if (layer == localPaintingInfo.rootLayer)
             break;
     }
+
+    // TODO(schenney): Not right, but hack to get something that applies a radius then figure out the correct way to do it.

[chrishtr, 2016/10/21 23:15:08]

This is to get the right positioning relative to the new graphics layer?

[Stephen Chennney, 2016/10/24 20:15:27]

Yes, the clipping container is in one layer (the parent's in the simple case)
and the mask is in another (the child's) and they are not at the same origin.
But it seems like there should be a better way to find their relative transform,
hence the TODO.

+    if (paintFlags & PaintLayerPaintingAncestorClippingMaskPhase) {
+        const LayoutObject* clippingContainer = paintLayer.clippingContainer();
+        LayoutPoint fragmentDelta(fragmentOffset);
+        paintLayer.convertToLayerCoords(paintLayer.root(), fragmentDelta);
+        LayoutPoint containerDelta;
+        clippingContainer->enclosingLayer()->convertToLayerCoords(clippingContainer->enclosingLayer()->root(), containerDelta);
+        LayoutPoint offset(containerDelta.x() - fragmentDelta.x(), containerDelta.y() - fragmentDelta.y());
+        LayoutSize size(toLayoutBox(clippingContainer) ? toLayoutBox(clippingContainer)->size() : LayoutSize(clippingContainer->enclosingLayer()->size()));
+        roundedRectClips.append(clippingContainer->style()->getRoundedInnerBorderFor(LayoutRect(offset, size)));
+    }
 }
 
 LayerClipRecorder::~LayerClipRecorder()