Fix border radius on composited children.

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

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "core/paint/LayerClipRecorder.h"
 
 #include "core/layout/ClipRect.h"
 #include "core/layout/LayoutView.h"
 #include "core/paint/PaintLayer.h"
 #include "platform/geometry/IntRect.h"
@@ skipping 53 matching lines @@
 
             // The PaintLayer's size is pixel-snapped if it is a LayoutBox. We can't use a pre-snapped border rect for clipping, since getRoundedInnerBorderFor assumes
             // it has not been snapped yet.
             LayoutSize size(layer->layoutBox() ? toLayoutBox(layer->layoutObject())->size() : LayoutSize(layer->size()));
             roundedRectClips.append(layer->layoutObject()->style()->getRoundedInnerBorderFor(LayoutRect(delta, size)));
         }
 
         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()
 {
     m_graphicsContext.getPaintController().endItem<EndClipDisplayItem>(m_layoutObject, DisplayItem::clipTypeToEndClipType(m_clipType));
 }
 
 } // namespace blink